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  • Munksgaard International Publishers  (154)
  • 1990-1994  (154)
  • 1970-1974
  • 1955-1959
  • 1992  (78)
  • 1991  (76)
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  • 1990-1994  (154)
  • 1970-1974
  • 1955-1959
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  • 1
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The cleaning effectiveness of different treatment methods for titanium abutments was evaluated using scanning electron microscopy (SEM). In the mandible of 4 beagle dogs, 25 titanium abutments were installed (modum Brånemark). After 16 weeks of plaque accumulation, mineralized deposits had formed on 23 abutments. Each of these abutments was subjected to one of the following treatment methods: scaling with (1) metal, (2) plastic, or (3) ultrasonic instruments;(4) air-polishing, (5) weekly rubber cup polishing or (6) daily brushing with a conventional toothbrush. Fourteen abutments were removed immediately after treatment. On 9 abutments, the scaling procedures and air-polishing were repeated after another 16 weeks of plaque accumulation. The abutments were prepared for SEM, and each of them was viewed and photographed at 3 different magnifications. The photomicrographs were evaluated by 3 examiners who, guided by reference pictures, gave each abutment a “cleanliness” score, ranking from 0 to 5. Regular rubber cup polishing and regular brushing resulted in the highest surface cleanliness, while the air-polishing procedure showed the lowest cleanliness score. None of the 3 scaling methods created a cleanliness score better than 3. The 3 scaling methods were considered equal in their cleaning effectiveness. No differences could be observed between surfaces treated 1 x or 2 x Taken the present findings and those of other studies concerning the effects of scaling on the surface roughness and biocompatibility into consideration, it was concluded that plastic scalers may be the instruments of choice for debridement of titanium implant surfaces.
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  • 2
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Speech may be affected by the transition from complete dentures to fixed prosthesis on osseointegrated implants (OIB). If so, is there any correlation between interdental spaces (open or closed) in the prosthodontic construction and deteriorated speech? 21 individuals advocated for maxillary OIB were randomised so that one half of the group got constructions with wide interdental spaces and the other half with minimised inter-dental spaces. All patients were examined audiologically and their speech was individually tape-recorded before and after treatment. Perceptual, acoustic, model and audiological analyses were made. Approximately 60% of the patients were judged to have indistinct speech after the treatment. The s-sound was perceptually and acoustically distorted. 67% of the patients suffered from hearing defects. No correlation between interdental spaces (open or closed) and deteriorated speech could be found. It is supposed, that hearing plays a part in the effort to adjust speech to a new maxillary OIB, and thus reduced hearing can enhance speech difficulties.
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  • 3
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The installment of endosseous dental implants has become an accepted treatment procedure, and the long-term clinical results appear excellent. The composition of the soft tissue environment, however, is different from that around natural teeth. One characteristic of original junctional epithelium is its association with plasminogen activator (PA) activity. In 11 patients with a total of 30 IT1 hollow-screw titanium dental implants, 16 biopsies were taken. Histologic cryostat sections were assayed for the presence of PA in the junctional epithelium. The results demonstrated that junctional epithelium around titanium implants yields PA activity in a manner very similar to that of natural teeth. The ability to produce this enzyme activity is not related to the developmental origin of the junctional cells, but to their position and function at the base of the gingival sulcus.
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  • 4
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The microflora around titanium implants and teeth in 4 beagle dogs was analyzed in order to follow the longitudinal development from healthy conditions to experimental gingivitis and periodontitis. A 2-month plaque control program was performed to establish healthy conditions on titanium implants and control teeth (baseline, day 0). Subgingival bacterial samples and radiographs were obtained. The plaque control was ceased and all measurements were repeated on day 21 (gingivitis). A new period of plaque control was initiated to re-establish healthy conditions (day 49). A cotton ligature was placed subgingivally around the implants and the control teeth to induce tissue breakdown. The ligatures were removed on day 91. The study was completed with registrations on day 121 (periodontitis). No significant microbiological difference was found between titanium implants and teeth in healthy conditions and in gingivitis and periodontitis. The mean total viable count increased 10 times on implants as well as on teeth. Streptococci were dominating at baseline: 40.2% on implants and 60.6% on teeth and decreased in gingivitis to 11.7% and 5.4%. When periodontitis had developed, the proportion of streptococci was 〈 1%. At baseline few Porphyromonas gingivalis and Prevotella intermedia were detected. They increased at gingivitis to 37.4% and 21.0%; when periodontitis developed, they comprised about 25.0%. Microbial colonization and establishment on titanium implants with healthy gingiva, experimental gingivitis and periodontitis follow the same pattern as on teeth.
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  • 5
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: An intimate contact between bone and titanium implants was first demonstrated in 1969. and since then the bone-implant interface of osseointegrated implants has been investigated extensively. However. investigations of the marginal tissues and the microflora associated with osseointegrated implants have almost exclusively been carried out over the last decade. This review covers the clinical, radiographic, histologic, and microbiologic studies of marginal tissues of osseointegrated oral implants. In general, successfully osseointegrated implants exhibit low amounts of plaque con-comitant with the absence of marginal inflammation. However, plaque accumulation may cause inflammatory reactions around the implants, sometimes giving rise to mucosal hyperplasia. Apparently, keratinized mucosa is not a requisite for the maintenance of peri-implant health if oral hygiene is adequate, but the presence of peri-implant keratinized mucosa is generally advocated. Alveolar bone loss around successful implants is minimal, but significant focal loss may occur due to plaque-induced inflammation or perhaps repeatedly extensive implant load. The progression of plaque-induced alveolar bone loss of osseointegrated implants may be different from that of teeth. It is unknown whether simultaneous marginal inflammation and excessive implant load further increase the loss of alveolar bone height. Both the light microscopic and ultrastructural characteristics of marginal tissues of implants and teeth are similar except for a lack of root cementum with inserting gingival collagen fibers of implants. Clinical inflammatory reactions are histologically characterized by an increased number of inflammatory cells infiltrating the connective tissue. The scattered subgingival microbiota associated with osseointegrated implants surrounded by healthy or slightly inflamed marginal tissues is similar to that of teeth with healthy gingiva. The microbiota associated with implants affected by marginal inflammation and bone loss is complex and consists predominantly of gram-negative anaerobic rods: this. again, is a similarity to periodontal disease.
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  • 6
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Eight non-submerged titanium implant screws were placed in the first upper molar edentulous sites of monkeys and subsequently kept loaded with single crown prosthesis 1 month following implantation. The animals were killed after a further 14 months and specimens including implant and adjacent teeth were processed for light and electron microscopy. Histological pictures of all samples showed the neck and most of the screw body to be surrounded by new bone. The soft tissue surrounding the implant post included pocket epithelium and supra-crestal connective tissue displaying collagen fiber bundles comparable to gingival ligaments. These peri-implant collagen fiber bundles arose from the neighboring alveolar crest, root cementum of adjacent teeth or, superficially, from the epithelium and followed a circular array around the implant neck.
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  • 7
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The purpose of this study was to investigate the possibility of antimicrobial treatment of peri-implant infections associated with a periodontitis-like subgingival microbiota. Nine partially or fully edentulous patients with titanium hollow cylinder implants were selected which showed loss of bone and probing depths ≥ 5 mm on one or several implants after at least 6 months following installation. They also yielded subgingival microbial samples with ≥ 106 CFU/ml, including ≥ 20% gram-negative anaerobic bacteria, The treatment included mechanical cleaning, irrigation of all peri-implant pockets 〉 3 mm with 0.5% chlorhexidine and systemic antimicrobial therapy (1000 mg ornidazole for 10 consecutive days). After therapy, bleeding scores decreased immediately and, over a one-year observation period, remained significantly lower than before treatment. A significant gradual reduction in mean probing depths was detected over this one-year period; only one case showed no improvement of local probing depth. Microbiological parameters indicated an instantaneous quantitative and qualitative change following treatment. Subsequently, several of these parameters tended to shift back towards pre-treatment values. In the second half of the observation period, however. this tendency was reversed, and levels significantly different from baseline were eventually established. This study demonstrated that treatment aiming at reducing the subgingival bacterial mass and suppressing the anaerobic segment had a beneficial effect in patients suffering from peri-implantitis.
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  • 8
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Several parameters have been described to determine success or failure in long-term evaluations of dental implants. One of these parameters is the observation of changes in peri-implant bone levels. Studies on submerged implants have analyzed the bone level changes in the pre- and post-loading phases. No such data exist for intentionally nonsubmerged implants. The purposes of this study were: (1) to test the applicability and reproducibillity of a simple computer-assisted method in the evaluation of changes in peri-implant bone levels;(2) to establish a baseline for the longterm radiographic follow-up; and (3) to evaluate changes in crestal bone levels adjacent to nonsubmerged IT1 implants between the 1-year and 2-year examination. Standardized periapical radiographs were obtained from 80 implants at the l-year and 2-year follow-up examinations after their placement. The implants were located in different jaw areas of 55 patients and supported single crowns or short-span fixed partial dentures. For each implant, the distance from implant shoulder to first crestal bone contact (DIB) was measured at the proximal surfaces with a digitizer/computer assembly. Statistically significant greater mean DIB were found at the l-year (baseline) evaluation for: (I) maxillary sites overall (4.10 x 1.02 mm (SD)) compared with mandibular sites overall (3.61 ± 1.03 mm);(2) maxillary anterior sites (4.08 ± 0.97 mm) compared with mandibular posterior sites (3.60 ± 1.05 mm); and (3) maxillary posterior sites (4.13 ± 1.12 mm) compared with mandibular posterior sites. No statistically significant changes in DIB occurred in any of the jaw locations between the l-year and 2-year evaluations. These results indicate similar changes in peri-implant bone levels for non-submerged implants over a 2-year period 1 as reported for submerged fixtures.
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  • 9
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The purpose of this research was to determine the nature of the residual hydroxyapatite (HA)-coated implant surface after treatment with various chemotherapeutic modalities, including: citric acid, chlorhexidine gluconate, hydrogen peroxide, tetracycline HCl, stannous fluoride, polymyxin B and a prototype plastic Cavitron tip. Implant surfaces were evaluated macroscopically, microscopically (scanning electron microscopy (SEM)) and spectrometrically (energy-dispersive spectrometry and X-ray diffraction). HA-substrate bond strength and dissolution testing was also performed for surfaces treated with a supersaturated citric acid solution. All treatments left either microscopic residues or a loss of surface roughness when viewed on SEM. A 30- to 60-s application of citric acid left a significantly greater coating thickness than all other treatments, whereas a 3-min application of citric acid removed significantly more HA than untreated controls. Significant changes in CaiP ratios were seen with most treatments. The clinical significance of this phenomenon is not known. No treatments altered the crystallinity of the residual HA coating. A l-min application of citric acid did not significantly alter the tensile bond strength of the coating to the substrate. The clinical significance of these findings is not known at present. However. when taken with results from previous studies. it appears that in treating the infected HA-coated implant surface, a 30- to 60-s application of citric acid (pH 1) may be beneficial in detoxifying the HA coating prior to regenerative procedures. Further in vitvo and in viva studies are necessary to evaluate the biological response to citric acid when used to detoxify the infected implant surface.
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  • 10
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The experiment was performed to evaluate the effects of long-standing plaque on the gingiva and peri-implant mucosa. 5 beagle dogs were used in the study. The mandibular right premolars were extracted. 3 months later, 3 titanium fixtures were installed and after another 3 months, abutment connection was performed. Plaque control, in the implant as well as the contralateral tooth regions, was maintained during a 4-month period prior to the start of the main experiment. On Day 0, the teeth and implant sections were examined with respect to plaque and gingivitis. The plaque control program was terminated. The animals were subsequently fed a diet which allowed gross plaque accumulation. After 90 days of undisturbed plaque formation, the dogs were re-examined and biopsies harvested from implants and contralateral teeth. On day 90, all teeth and implants had accumulated large amounts of plaque. The soft tissue at implants and teeth bled on gentle probing. The histological examination of the gingiva and the peri-implant mucosa revealed:(i) both tissues contained an inflammatory cell infiltrate; ICT, (ii) the apical extension of ICT was more pronounced in the peri-implant mucosa than in the gingiva and (iii) the composition of the 2 lesions had many features in common.
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  • 11
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: It has been documented that the long-term clinical outcome of the Brånemark® system is very favourable. However, failures do occur before and after loading. This study examined the differences in marginal bone loss between standard and self-tapping fixtures and attempted to explain excessive marginal bone loss or loss of osseointegration during the first 3 years of loading. Marginal bone loss (scored on long cone radiographs) and fixture failure rate were compared for different fixture designs. For standard fixtures, in comparison with self-tapping fixtures, the failure rate was clearly higher before as well as after loading. However, for successful fixtures no difference in marginal bone loss was observed. For the conical fixtures an increased marginal bone loss around the smooth part was observed. The effect of fixture overload, marginal bone height and loss of osseointegration was examined in 69 patients with 1 and 15 patients with 2 fixed full prostheses, and in 9 patients with an overdenture in the upper jaw. Excessive marginal bone loss (more than 1 mm) after the first year of loading and/or fixture loss correlated well with the presence of overload due to a lack of anterior contact. the presence of parafunctional activity and osseointegrated full fixed prostheses in both jaws.
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  • 12
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In order to improve the prosthetic versatility of the ITI-Bonefit implant system, a clinical technique was tested whereby a custom made post and core buildup was cemented into implants. Specially designed threaded and serrated posts were machined in precious metal. After the posts were seated into the threaded channel of the implants, cores were built using autopolymerizing resin. Those were then cast and cemented into the implants. For the remainder of the procedure, the buildups were treated like natural abutments using conventional prosthodontic techniques. Mechanical tests were performed to assess the clinical viability of these buildups. The ultimate tensile strength of annealed posts lies in the 700–800 N range. By comparison, the pull-out resistance of posts cemented into natural roots ranged between 108 and 177 N, and the maximum pull-out resistance of manufactured abutments is about 1040 N. When the resistance against lateral forces was tested, the cemented build-ups ranged between 981 and 1128 N. whereas natural teeth fractured between 206 and 903 N depending on the diameter of the root. Manufactured abutments failed at stress levels of about 1020 N. Considering these favorable results, we conclude that the technique described above can be applied clinically for further investigation. Additionally, we suggest some modifications in implant design that would enhance the versatility of the system.
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  • 13
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The aim of this study was to test whether healing of extensive transosseous defects in the calvaria can successfully be achieved using guided bone regeneration. The results demonstrated complete osseous bridging of the skull defect in the test specimen. In the control specimen, fibrous connective tissue occupied the area of the skull defect.
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  • 14
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: For several years, osseointegrated implant-supported overdentures have been used in the rehabilitation of full edentulism with excellent results, at least in the lower jaw. This study involved 3 groups of patients with different prosthetic reconstructions:(1) mandibular overdentures supported by 2 implants connected by a bar (30 patients), (2) mandibular fixed prostheses supported by 4–6 implants (25 patients) and (3) mandibular complete dentures without implant support as controls (85 patients). The primary aim of this study was to examine on orthopantomograms (by means of the area index to minimize distortion and magnification errors), posterior mandibular ridge resorption in the 3 treatment groups. The present data demonstrated a minimal posterior mandibular ridge resorption in patients with fixed implant-supported prostheses. A more considerableposterior ridge resorption was observed in the complete denture group and especially in the overdenture wearers. For the latter, the annual posterior jaw bone resorption after the post-extraction remodeling period of 6 months, was 2- to 3-fold that of full denture wearers. When patients were edentulous for more than 10 years, the difference between the 2 latter groups disappeared. It is suggested that although the overdenture design on 2 implants offers advantages from a financial and failure rate point of view, its indications in younger patients should cautiously be evaluated in a long-term perspective concerning posterior mandibular bone resorption.
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  • 15
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The aim of the present investigation was to assess the effect of de novo plaque formation on the gingiva and masticatory mucosa around teeth and implants. The study was performed in 5 beagle dogs which at the initiation of the experiment were 15 months old. During a preparatory period, the mandibular right premolars were extracted, 3 fixtures installed, abutment connection performed and a 4-month period of plaque control completed. A clinical examination was performed and biopsies of the second mandibular premolar (Pz) and the contralateral implant site (2P) were sampled. The dogs were allowed to form plaque during a period of 3 weeks. The clinical examination was repeated and biopsies harvested from the 2 remaining implants and the contralateral tooth sites. The tissue samples were prepared for histometric and morphometric analysis. Both the masticatory mucosa at implants and the gingiva responded to de novo plaque formation with the development of an inflammatory lesion. The size as well as the composition of the lesions in the 2 tissues had many features in common. It was concluded that the mucosa around implants and the gingiva around teeth had a similar potential to respond to early plaque formation.
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  • 16
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The purpose of this study was to develop a repeatable method for measurement of bone support around root form and blade implants suitable for use in high-quality but unstandardized radiographs. 10 phantoms were fabricated to simulate progressive osseous defects around implants. Radiographs were taken in triplicate and digitized. Specialized software was written which placed a grid of known dimensions over the implant so that the top and the bottom of the grid were at the neck and the base of the implant, respectively. The investigators selected the edge of the bone at each point where the grid intersected the implant and the software automatically detected the implant edge. The software also outlined and displayed the defect on the computer monitor. Measurements were performed 5 times and the standard deviation was taken as a measure of the repeatability of the method. Repeatability for blades and root forms was 0.19 ± 0.07 mm and 0.08 ± 0.03 mm, respectively. There was no significant difference in the ability to measure bone loss in the blade versus the root form (pequals;0.17, NS). These results indicate that this semi-automated computer-assisted method for measuring bone loss around implants is repeatable and may be of value for clinical trials using either root form or blade implants.
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  • 17
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: This report derives an exact, but practical, expression for calculating the stack effect from air densities and leakage distribution using the power law formulation of envelope leakage. The neutral height-the height at which there is no stack-related indoor-outdoor pressure difference-is a key intermediate in stack modeling. This report defines a computable parameter called stack height, which contains all of the leakage distribution information necessary for estimating stack flows, thus freeing the model from specific assumptions (e.g. that the leakage is separable into evenly distributed floor, wall, and ceiling components). Example calculations, including comparisons with other models, as well as validations using measured data from dwellings, are also presented. The dimensionless neutral level, which is related to the neutral height, is often used as an indicator of leakage distribution and in superposition. Its definition and role in these instances are discussed in detail. The more exact formulation is then used to analyze the simple box cases normally assumed in infiltration modeling and other approximations. Measured ventilation data will be used to infer leakage distributions and neutral levels as well as for example calculations.
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  • 18
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The vertical temperature profiles have been measured in a full-scale office room ventilated by displacement. Different wall radiative emissivities have been employed to study the effect of thermal radiation. The change of the vertical locations of the heat source does not affect the stationary front, but modifies the temperature profile.Two new nodal models, i.e. a four-node model and a multi-node model, are developed for predicting the temperature profile based on the flow and thermal characterization in the room. Agreement between the models and the experiments are very good. The calculated results are applied to show that the temperature profile is influenced considerably by the heat conduction through the walls and the thermal radiation between the wall surfaces. The models developed can be used for design purposes, as well as to supply the thermal boundary conditions in a CFD code.
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  • 19
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 20
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The indoor air quality (IAQ) programme of the World Health Organization Regional office for Europe was initiated in the mid-seventies when it was realized that over 70% of the general population spends its time indoors in homes, office buildings, schools, hospitals, transportation means, etc. The first meting of experts on health aspects related to IAQ was convened in 1979, being probably the first international meeting on IAQ with participation from eastern and western Europe as well as from North America. Seven meetings followed between 1982 and 1990, at which the “sick building” syndrome, IAQ research, formaldehyde and radon, organic pollutants, biological contaminants, combustion products, and mineral fibres were discussed. A ninth meeting on sources, control and mitigation is planned for 1991.
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  • 21
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: In order to cumpare the peformance of different supply diffuers of ventilation air, the airflow passern, temperature stratifiation and contaminant dispersion in a furnitured office ventilated by three kinds of air diffuer were numerically investigated. The air diffuers studied in this paper are a quarter-cylinder displacement diffuer on the floor and mixing diffuers (linear and vortex diffuers) on the ceiling. The heat sources in the of-fice are considered to be 50% convective and 50% radiative. The k-ɛ two-equatwn model of turbulence is employed to predict the turbulent diffusion.The results show that the displacement diffuser provides a rather uniform flow field with low velocify in most areas, and the vertical temperature difference from floor to ceiling is as high as 6 K. With the linear diffuser, the air velociry is high, and the temperature is uniform both horizontally and vertically. The air velocity generated by the vortex diffuser is moderate. The distributions of the temperature and the contaminant are rather uniform.
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  • 22
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Residual airborne concentrations of methyl bromide (MB) were measured in 10 houses after fumigation with MB at a mean exposure of 53, 369 ppm. hr to control drywood termites. Sulfuryl fluoride (SF) residues were measured in 10 and 3 houses after SF fumigation at 59,161 and 33,531 ppm. hr, respectively. Prior to sampling, all 23 houses were aerated to MB and SF threshold limit values (TLVs) of 5 ppm following label-directed procedures. Immediately following aeration, doors and windows of houses were closed and ventilation system deactivated. During this initial 2-h closure period, the mean concentration among MB-fumigated houses increased to 17.5 ppm MB at 90 min with room means of all 10 MB houses exceeding TLV. Residue means at 120 min among SF-fumigated houses were 4.6 and 5.0 ppm SF with 3 and 2 houses exceeding TLV for the high and low SF exposures, respectively. After a second aeration and closure, levels exceeded TLV in 5 of 6 MB houses monitored during this period, but not in any of the 9 SF houses sampled. Post-aeration residues tended to be higher in bedrooms and bathrooms. Because of the excessive transient desorption and diffusion of both fumigants revealed by this study, modified aeration procedures are needed to ensure that occupant exposure levels do not exceed safety standards.
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  • 23
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Indoor air bacteria and fingal spore levels were studied in 71 non-complaint homes. lk data were analyzed according to the season and the higher limit of the range within which 95% of the cases fall was computed. On the basis of the data the following highest normal levels are proposed for winter: for bacteria 5000 cfulm3 and for fingal spores 500 cfulm3. The recommended levels apply in a subarctic climate for urban and suburban homes when the measurements are made using the same method as in this study. We recommend that if abnormal indoor sources are suspected, indoor samples should be taken in winter when the ground is frozen and covered with snow. At that time, the background levels are at their lowest and the abnormal indoor sources are most easily detected. lk recommended levels should not be used as an indicator of a health risk, but as an indication of abnormal indoor sources or insufficient ventilation.
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  • 24
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Indoor carbon dioxide (CO2) concentration can be used to estimate the degree of air recirculation and outdoor air supply rate. Three types of CO2 detector tubes were evaluated by using Fourier Transform Infra-Red (FTIR) Spectroscopy as a reference method. Two types of detector tubes (Draeger CH 30801 and Kitagawa 126 B) showed a good correlation with the reference method (r = 0.98), the 95% confidence interval of the slope being 0.89-1.06 and 0.80-0.95, respectively in linear regression analysis. The third type (Gastec 2LL.) showed lower correlation (r = 0.91) and a wider 95% confidence interval (0.52-0.80) of the slope. A t CO2 concentrations in the range 800-1000 5 l/l(ppm), control values suggested for the indoor environment, the Draeger and the Gastec tubes underestimated the CO2 concentration, while the Kitagawa tube showed a correct value. The difference in reading between observers was similar for all three brands of detector tubes (5-7%), expressed as relative standard error No significant influence of the air humidity or temperature on the readings could be demonstrated. It is concluded that some brands of CO2 detector tubes can be used to measure indoor carbon dioxide concentration with sufficient precision and accuracy. Since the relative error is relatively large at lower CO2 concentrations, the use of such tubes for the determination of air recirculation in ventilation systems should be avoided. As a crude estimate of the outdoor air supply rate, however, CO2 detector tubes may be used. In order to minimize the error in reading, the type of detector tube and the need for recalibration should be considered. When using CO2 measurements as an estimate of outdoor air supply rate, the influence of age and work-load on the individual's emission of CO2 and the time needed to reach equilibrium, should also be taken into consideration.
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  • 25
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Where indoor concentrations are high, radon entry into houses with basements is usually due primarily to the convective transport of soil gas through openings in the subsurface part of the building shell. The factors determining the rate of entry may conveniently be divided into those associated with the undisturbed soil and those associated with the structure and its surroundings. This paper uses a numerical model to determine the influence of the latter factors on the soil gas and radon entry rates. The most important of these is the presence or absence of a gravel layer below the slab; the presence of the gravel can increase the radon entry rate through the perimeter gap betureen the foundation footer, slab, and wall (slab-footer gap) by as much as a factor of 5 over that for homogazeous soil. The permeability of the gravel becomes important when the soil permeability is unusually high, i.e., greater than 10−10 m2. Of lesser importance are the thickness of the gravel layer and the radium content of the gravel. The sizes and numbers of openings in the slab are relatively unimportant so long as the total opening area is vey small compared to the slab area. If cracks in the basement walls are major radon entry paths, as in concrete-block construction, the permeability of the soil restored to the region adjacent to the walls after completion of construction (backfill) is the determining factor in convective radon entry through these openings; if the soil is packed loosely, so that there is a gap between wall and soil, radon entry through a wall crack may be further increased by as much as a factor of 7.5. Radon entry rates through the slab-footer gap and through openings in the slab are only weakly influenced by the permeability of the backfill. The resistance of the perimeter gap to soil gas entry becomes significant when the gap width falls below 0.001 m, assuming a soil permeability of 10−11 m2.
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  • 26
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: A six-week study of indoor and outdoor air pollutants was conducted in central New Jersey during the summer months of 1989. Three institutional settings for elderly and child care were investigated for the potential of acidic aerosol exposures. The indoor penetration by fine aerosols was 〈 70% at all three institutions. For locations with closed ventilation, it was 15-25% lower than for the open-window setting. Relative to outdoor levels, indoor acidic sulfate aerosols were 30-57% neutralized. Indoor levels of ammonia were = 10 × higher than corresponding outdoor values, which were consistent with calculated emission rates from human occupants. From estimates of total daily exposure, 75% of the daily dose of aerosol acidity for the elderly was due to indoor exposures. Doses received by the elderly and children ranged from 290 to 1100 nmoles of acid (15 to 55 ug as H2SO4) in a 24—h period with “worst-case” dose received by children as high as 3400 nmoles of acid in the daytime. These doses were comparable to the levels observed in clinical and epdemiological studies where health effects result. The daily dose of acid delivered to children was calculated to be 2 to 4 × higher than the dose to the elderly population. The calculations for children indicate that more than 90% of their dose on a summer day may come from outdoor exposures. These data suggest that indoor settings are protective, but children may still be at risk from summertime acidic aerosol exposure, depending on their activities outdoors.
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  • 27
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The main source of high radon concentration indoors is the exhalation of radon from the soil. In the western part of Germany, two interesting regions, “Eifel” and “Hunsrück”, are selected for these radon investigations. The first region is an area with silt and sandstone of low uranium content but with tectonic fractures caused by postvolcanic activity, whereas in the part of the “Hunsrück” under consideration, the uranium concentration in the ground formerly allowed the extraction of uranium ores. An electrostatic deposit of the first radon daughter (Polonium-218-ion) onto a surface barrier detector and the subsequent analysis of the measured alpha spectra enables the determination of the concentration of radon in dwellings, its diffusion through and its exhalation rate from the soil. A maximum indoor concentration of radon of 8 kBq★m−3 in a bedroom and approximately 35 kBq★m−3 in a cellar room were determined in a house built in 1976. The daily variation between the minimum and the maximum concentration indoors amounts to a factor of ten. In these regions the radon concentration outdoors varies between 20 and 150 Bq★m−3. The exhalation rates of radon from the soil are found to range from 0.002 to 1 Bq★m−2★S−1 The effects of sealing the ground slab with polyurethane and removing the air under the ground slab by suction will be presented.
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  • 28
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: This paper is based on field measurements in auditoria, carried out in Norway and in Switzerland. In both cases carbon dioxide (CO2 was chosen as the relevant indicator to establish ventilation demand.Investigations in Norway focus on the aspects of airflow, patterns, ventilation efficiency and air quality. Intensive monitoring and numerical calculations with the computer code KAMELEON were performed.The Swiss project places more emphasis on impacts of demand control on energy consumption and occupant response. The results of the fild measurements, of the questioning of occupants, as well as of simulations which were carried out with the simulation code TRNSYS are presented.Results show that demand control with CO2, as indicator for ventilation demand can maintain an acceptable indoor climate while allowing substantial energy savings.These investigations were conducted as part of the IEA (International Energy Agency) research programme “Annex 18: Demand Controlled Ventilating Systems”.
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  • 29
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The TVOC summation of masses of non-reactive substances has often been used as a practical way of reporting environmental measurements of volatile organic compounds. This total concentration, moreover, is often used as an indication of the potential of a multiomponent atmospheric pollution with substances of low chemical reactivity to cause chemically induced sensory irritation. This use of the TVOC indicator has never been standardized. Various authors have used different measuring techniques and the results have been used to predict certain types of health effect. This article discusses the toxicological background for the TVOC concept in relation to nonspecific sensory irritation and identifies some theoretical limitations in its use within this context. The TVOC indicator of nonspecific sensory irritations should be based only on a limited range of compounds and should be interpreted as a lower limit of the possible intensity of sensory irritation. Based on the discussions, some precautions are recommended with respect to measurements of TVOC and interpretation of the measurements.
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  • 30
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Air cleaning as a means of mitigating the risks arising from exposure to indoor radon progeny has been evaluated in a single-family house in the north eastem US. using an automated, semi-continuous activity-weighted size distribution measurement system. The measurements included radon concentration, condensation nuclei count, and activity-weighted size distribution of radon decay products. Measurements were made in the house with and without an operating air filtration system and with various particle sources common to normal indoor activities operating. Aerosols were generated by running water in a shower, candle burning, cigarette smoking, vacuuming, opening doors, and cooking. Using a room model, the changes in attachment rates, average attachment diameters, and deposition rates of the unattached fraction with and without the air cleaning system were calculated. In the presence of active aerosol sources, the air filtration unit typically reduced the concentration of particles within the hour following the end of particle generation. After candle burning, cigarette smoking, and vacuuming in the bedroom, the reductions of PAEC by air filtration are about 60% with the air filtration system operating in the bedroom. During cooking in the kitchen, the reductions of PAEC in the bedroom with the air filtration system were about 40%. However, for all cases the dose reductions were smaller than the particle and PAEC reductions. For those particles that were generated within the bedroom, there was a 20% to 50% reduction in dose. In the case of cooking where the door was open and particles infiltrated from the rest of the house, the dose reduction was only 5% on average and appears to be insignificant. Thus, the dose reductions were h e r than the reductions in activity concentration, but there were no cases where the estimated dose actually increased.
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  • 31
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The paper presents the results of preliminary investigations on the applicability of commercial polyethylene films to permeation-type passive samplers for the preconcentration of organic indoor air pollutants. The samplers were calibrated in exposure chambers in the atmosphere of standard gaseous mixtures containing vapours of m-xylene, styrene, m-dichhobenzene and cyclohexanone – volatile organics often encountered in indoor atmospheres. The permeation rates remained constant for all the film in the entire investigation period (9 months). Of the materials examined, the most suitable proved to be Cryovac EFDX 003 (28 μm), ensuring the highest permeation rates.
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  • 32
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: A total of 115 Danish dwellings were investigated during the winter season in order to evaluate the indoor environment. The sample was considered representative of Danish dwellings. Measurements of air-exchange rates in the bedrm showed a very low natural venthtion with a median air-exchange rate of 0.28 air changes per hour (ach) (interqmmle range (IQR): 0.12 –0.56).18% of the dwellings had a natural air-exchange below a detectable limit of 0.10 ach and 72% had air-exchanges rates below the requirements in Danish Building Codes of 0.50 ach. The investigations showed a statistically signifiant inverse correlation between air-exchange rates and absolute indoor humidity. Concentrations of formaldehyde and volatile organic compounds were measured in 36 dwellings. The median formaldehyde concentration was 0.037 mg/m3 which is well below the recommended indoor TLV The concentration of VOC in some cases reached a level that may be of importance for persons with sensitive airways. It is concluded that natural ventilation in a great number of Danish dwellings is too low fiom a health point of view and that the requirements in Danish Building codes are insufficient to ensure acceptable air-exchange rates.
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  • 33
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Two models, one physical and the other empirical, have been applied to the characterization of emission data of thin film products tested in small environmental chambers and have been compared in temts of emission results and m e of use. The physical model, being based on equations with coefficients bearing a physical meaning, is, in principle, more informative than the empirical one. However, it is uncertain whether it always gives accurate and unambiguous results. Moreover, in orakr to be exploited in a reasonable amount of time, it requires the use of non-linear regression routines, e.g. those fom SAS Institute Inc., implemented on mainframes and, even then, it is often quite diffiult to handle. The empirical model does not rely explicitly on physical effects. Although by definition it can only describe but not interpret the experimental data, it does estimate parameters describing the emission with an accuracy comparable to that of the physical model. It is easier to handle than the latter as it can employ non-linear regression routines such as those used on personal computers.
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  • 34
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Screening of complementary DNA (cDNA) libraries constructed from poly(A) rich RNA isolated from young developing ovaries of Narcissus cv. Fortune and Hippeastrum hybr. resulted in the isolation of multiple lectin cDNA clones. Although the lectin clones show a high degree of overall homology within their coding region, they clearly differ from each other at some positions in their nucleotide sequence and deduced amino acid sequence. Moreover, since some differences in the sequence result in different charges along the lectin polypeptides, the different cDNA clones encode lectins with different isoelectric points, which explains the occurrence of multiple lectin isoforms in Narcissus and Hippeastrum at the molecular level. Furthermore, Southern blot analysis of genomic DNA isolated from Narcissus and Hippeastrum yielded numerous restriction fragments hybridizing with lectin cDNA probes leaving no doubt that the Narcissus and Hippeastrum lectins, like the Galanthus nivalis lectin, are encoded by families of closely related lectin genes.
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  • 35
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In many organisms, the synthesis of heat shock proteins during heat shock is concomitant with the cessation of at least a portion of normal cellular protein synthesis. Heat shocked barley aleurone layers selectively stop the synthesis and secretion of secretory proteins. Exposure to 40°C causes a disruption of endoplasmic reticulum (ER) lamellae, which we have hypothesized leads to the destabilization of otherwise stable mRNA previously associated with ER-bound polyribosomes. We report here that this was also observed in wounded carrot (Daucus carota L.) root parenchyma tissue which synthesizes and secretes cell wall proteins when mechanically wounded. Nondenaturing cationic polyacrylamide gel electrophoresis of radiolabeled proteins indicated that heat shock caused the cessation of the synthesis and secretion of extensin, a hydroxyproline-rich cell wall glycoprotein. Northern blot analyses indicated that the mRNA levels for both extensin and another cell wall protein (p33) were rapidly diminished during heat shock. Under nonheat shock conditions extensin mRNA had a half-life of greater than 4 h, but this appeared to be reduced to less than 30 min during heat shock. There was also a concomitant dissociation of ER lamellae in wounded, heat shocked carrot root tissue, as observed by transmission electron microscopy. These observations indicate that this response may be universal among plant secretory tissues.
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  • 36
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    Physiologia plantarum 86 (1992), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The gas exchange characteristics of intact attached nodulated roots of pea (Pisum sativum cv. Finale X) and lupin (Lupinus albus cv. Ultra) were studied under a number of environmental conditions to determine whether or not the nodules regulate resistance to oxygen diffusion. Nitrogenase activity (H2 evolution) in both species was inhibited by an increase in rhizosphere pO2 from 20% to 30%, but recovered within 30 min without a significant increase in nodulated root respiration (CO2 evolution). These data suggest that the nodules possess a variable barrier to O2 diffusion. Also, nitrogenase activity in both species declined when the roots were either exposed to an atmosphere of Ar:O2 or when the shoots of the plants were excised. These declines could be reversed by elevating rhizosphere pO2, indicating that the inhibition of nitrogenase activity resulted from an increase in gas diffusion resistance and consequent O2-limitation of nitrogenase-linked respiration. These results indicate that nodules of pea and lupin regulate their internal O2 concentration in a manner similar to nodules of soybean, despite the distinct morphological and biochemical differences that exist between the nodules of the 3 species. Experiments in which total nitrogenase activity (TNA = H2 production in Ar:O2) in pea and lupin nodules was monitored while rhizosphere pO2 was increased gradually to 100%, showed that the resistance of the nodules to O2 diffusion maintains nitrogenase activity at about 80% of its potential activity (PNA) under normal atmospheric conditions. The O2-limitation coefficient of nitrogenase (OLCN= TNA/PNA) declined significantly with prolonged exposure to Ar:O2 or with shoot excision. Together, these results indicate a significant degree of O2-limitation of nitrogenase activity in pea and lupin nodules, and that yields may be increased by realizing full potential activity.
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  • 37
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In order to manipulate the shoot demand for mineral nutrients per unit root weight, maize (Zea mays L.) seedlings were grown in nutrient solution with different temperatures in the root zone and at the shoot base. The aerial temperature was kept uniform at 24/20°C day/night. At a root zone temperature (RZT) of 24°C, shoot growth was reduced by decreasing the shoot base temperature (SBT) to 12°C; at a RZT of 12°C, shoot growth was increased by raising the SBT to 24°C. At both RZT root growth was not affected by the SBT. Thus, the shoot demand for nutrients per unit root was either increased by raising, or decreased by lowering the SBT. The net uptake rate of potassium (K), as determined from accumulation rates between sequential harvests, was not affected within the first 3 days after lowering the SBT, whereas net translocation rates of K into the shoot and translocation rates in the xylem exudate of decapitated plants were markedly reduced. Obviously, translocation of K into the shoot seems to be regulated independently from K uptake into the root cells. Translocation rates of K in the xylem exudate of decapitated plants were markedly reduced when the nutrient solution was replaced by CaCl2 solution during exudation. But, depending on the SBT before decapitation, significant differences remained in the translocation rates of K even when K uptake from the nutrient solution was prevented.From the results it is suggested that xylem loading of K is regulated separately from K uptake from the external solution and that the adaptation of K translocation to shoot demand is coupled with an altered capacity of the root for xylem loading.
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  • 38
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Previous work has shown that the presence of kaempferol triglucoside (K9) in soybean (Glycine max L. Merr.) leaves is associated with reduced numbers of stomata, especially on the upper surface. In the present test, shade was imposed on soybean plants as a means of altering the level of K9, and thus testing the relationship between quantities of K9 and stomatal density. Five lines of soybean that differ in their complement of flavonol glycosides were grown in the field unshaded and also with a 64 and 80% reduction in daylight intensity. Samples of the second, sixth and tenth trifoliate leaves were taken at 34, 53 and 77 days after planting. Shade reduced the quantities of flavonoids on a per leaf and a per unit area basis. Shade had no effect on stomatal density in lines containing K9, but reduced stomatal density in lines lacking K9. We envisage two opposing effects of shade on stomatal density: a direct effect in which shade reduces numbers, and an indirect effect in which a decrease in K9 content allows an increase in stomatal density. The net effect of shade on lines containing K9 appears to be the maintenance of a constant stomatal density. The quantity of K9 was highly correlated with stomatal density within all treatment combinations, and with all treatments combined.
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  • 39
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Seeds of white clover (Trifolium repens L., cv. Podkowa) were germinated at water potential ψ=−0.3 MPa in darkness, at 25°C. A short exposure to blue light (B) inhibited germination in a manner similar to that described earlier for red (R) and far-red (FR) light (Niedźwiedź-Siegień and Lewak 1989). No reversibility of B, R and FR effects was observed. Saturation irradiance and energy was the lowest for R and the highest for B. The reciprocity of irradiance versus time of exposure was observed only for non-saturating irradiances of B, R and FR.
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  • 40
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    Physiologia plantarum 86 (1992), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The relationship between water availability and ethylene production was studied in 24-year-old trees of Norway spruce [Picea abies (L.) Karst.] growing on experimental plots with different water availability. Ethylene and oxygen were collected from the cambial/xylem region and heartwood in the stem using non-destructive sampling methods. Xylem sap flow was measured in stems using a heat-balance technique. Pre-dawn water potential of shoots was used to assess the water status of the trees. Growth was calculated from increments in stem basal area. The highest ethylene concentrations were found in irrigated trees that also, as compared to the other treatments, showed the most rapid flow rate of sap, the highest pre-dawn water potential, and the most rapid growth. By contrast, the lowest ethylene concentrations were measured in trees to which artificial drought was induced. Such trees also showed the lowest water transport, lowest water potential and relatively slow growth. Thus, no signs of drought-induced ethylene production were found in this study, contrary to the general contention of a positive relation between drought stress and ethylene production.
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  • 41
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: We have studied the role of endogenous auxin on adventitious rooting in hypocotyls of derooted sunflower (Helianthus annuus L. var. Dahlgren 131) seedlings. Endogenous free and conjugated indole-3-acetic acid (IAA) were measured in three segments of hypocotyls of equal length (apical, middle, basal) by using gas chromatography-mass spectrometry with [13C6]-IAA as an internal standard. At the time original roots were excised (0 h), the free IAA level in the hypocotyls showed an acropetally decreasing gradient, but conjugated IAA level increased acropetally; i.e. free to total IAA ratio was highest in the basal portion of hypocotyls. The basal portion is the region where most of root primordia were found. Some primordia were seen in this region within 24 h after the roots were excised. The quantity of free IAA in the middle portion of the hypocotyl increased up to 15 h after excision and then decreased. In this middle region there were fewer root primordia, and they could not be seen until 72 h. In the apical portion the amount of free IAA steadily increased and no root primordia were seen by 72 h.Surgical removal of various parts of the hypocotyl tissues caused adventitious root formation in the hypocotyl regions where basipetally transported IAA could accumulate. Reduction in the basipetal flow of auxin by N-1-naphthylphthalamic acid and 2,3,5-tri-iodobenzoic acid resulted in fewer adventitious roots. The fewest root primordia were seen if the major sources of endogenous auxin were removed by decapitation of the cotyledons and apical bud. Exogenous auxins promoted rooting and were able to completely overcome the inhibitory effect of 2,3,5-tri-iodobenzoic acid. Exogenous auxins were only partially able to overcome the inhibitory effect of decapitation. We conclude that in sunflower hypocotyls endogenously produced auxin is necessary for adventitious root formation. The higher concentrations of auxin in the basal portion may be partially responsible for that portion of the hypocotyl producing the greatest number of primordia. In addition to auxins, other factors such as wound ethylene and lowered cytokinin levels caused by excision of the original root system cuttings must also be important.
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  • 42
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Tomato (Lycopersicon esculentum L. cv. Rutgers) seedlings germinated on 2% agar containing the inhibitor of ethylene action, silver thiosulfate (STS), failed to insert their radicles into the agar. The growing seedlings developed a corkscrew morphology because of their inability to develop a gravitropic axis. Treatment with STS increased root length, and decreased hypocotyl elongation. These effects were also observed in seedlings germinated in atmospheres containing 2 000 µl 1−1 2,5-norbornadiene (NBD), another inhibitor of ethylene action. Neither of the inhibitors suppressed root penetration by seedlings grown on soft agar (0.5%). The altered pattern of growth appears to be due to restricted water uptake, since water application restored normal growth but not root penetration. Under low impedance, the rate of ethylene production was higher on STS- or NBD-treated roots. Increasing the concentration of agar in the growing medium increased ethylene production in untreated roots, and reduced that of those treated with inhibitors. The inability of roots to penetrate impeding agar surfaces was also observed in seedlings of an ethylene-resistant mutant (er) of Arabidopsis thaliana. These data indicate that ethylene plays a role in the response of roots to mechanical impedance, and that inhibition of their action impaired root insertion through compressed media. Possible mechanisms involved in these processes are discussed.
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  • 43
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Although the inhibitory effects of high concentrations of mineral N (〉 1.0 mM) on nodule development and function have often been studied, the effects of low, static concentrations of NH4+ (〈 1.0 mM) on nodulation are unknown. In the present experiments we examine the effects of static concentrations of NH4+ at 0, 0.1 and 0.5 mM in flowing, hydroponic culture on nodule establishment and nitrogenase activity in field peas [Pisum sativum L. cv. Express (Svalöf AB)] for the initial 28 days after planting (DAP). Peas grown in the presence of low concentrations of NH4+ had significantly greater nodule numbers (up to 4-fold) than plants grown without NH4+. Nodule dry weight per plant was significantly higher at 14, 21 and 28 DAP in plants grown in the presence of NH4+, but individual nodule mass was lower than in plants grown without NH4+. The nodulation pattern of the plants supplied with NH4+ was similar to that often reported for supernodulating mutants, however the plants did not express other growth habits associated with supernodulation. Estimates of N2 fixation indicate that the plus-NH4+ peas fixed as much or more N2 than the plants supplied with minus-NH4+ nutrient solution. There were no significant differences in nodule numbers, nodule mass or NH4+ uptake between the plants grown at the two concentrations of NH4+. Nodulation appeared to autoregulate by 14 DAP in the minus-NH4+ treatment. Plant growth and N accumulation in the minus-NH4+ plants lagged behind those of the plus-NH4+ treatments prior to N2 fixation becoming well established in the final week of the experiment. The plus-NH4+ treatments appeared not to elicit autoregulation and plants continued to initiate nodules throughout the experiment.
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  • 44
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The specific activity of NADH-glutamate dehydrogenase (GDH, EC 1.4.1.2) in leaf protoplasts (Brassica napus L. cv. Bronowski) was initially low and progressively increased during culture in Murashige and Skoog (MS) medium and MS (−NH4) (ammonium nitrate-free MS) medium in the dark. Native polyacrylamide gel electrophoresis (PAGE) and tetrazolium staining revealed that the high specific activity of NAD-GDH (deamination) in leaves correlated with the cathodal isoenzymes, and the high specific activity of NADH-GDH (amination) in leaf protoplasts to the anodal ones. Changes in isoenzyme pattern were correlated with an increase in the specific activity of NADH-GDH but not with the NADH-GDH/NAD-GDH ratio. The increase in NADH-GDH (amination) activity of leaf protoplasts was correlated with the occurrence of the isoenzyme GDH7, which was not detected in leaves.
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  • 45
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: We observed that guard cell protoplasts isolated from leaves collected at midday from Nicotiana glauca Graham (tree tobacco) did not give the same physiological responses to light as those isolated from leaves collected in early morning. Based on that observation, we attempted to determine whether there were significant differences between the physiological responses of guard cell protoplasts isolated from leaves collected before dawn (with closed stomata) and those isolated from leaves collected at midday (with open stomata). We isolated guard cell protoplasts from leaves collected before dawn and at midday and compared (1) rates of red and blue light-induced pH changes in weakly buffered media caused by changes in their metabolism, (2) their rates of oxygen consumption in darkness and oxygen evolution in light and (3) relative rates of decay of variable chlorophyll a fluorescence in their chloroplasts. Studies with the vital stain fluorescein diacetate failed to reveal any significant differences in the viabilities of protoplast preparations from leaves collected before dawn and at midday. Furthermore, protoplasts from leaves collected at these times swelled to similar extents in an osmotic medium containing 10 µM fusicoccin and 5 mM KCI. Nevertheless, rates of light-induced pH changes, rates of oxygen consumption and evolution and rates of decay of variable chlorophyll a fluorescence were all lower in preparations of guard cell protoplasts from leaves collected at midday than in preparations from leaves collected before dawn. Initial volumes of guard cell protoplasts isolated from leaves collected at midday were 150% of those of guard cell protoplasts isolated from leaves collected before dawn. We suggest that the differences in responses of guard cell protoplasts isolated from leaves collected before dawn and at midday may be caused by (1) nonoptimal isolation conditions for guard cell protoplasts prepared from leaves collected at midday, (2) the lower surface-to-volume ratio of guard cell protoplasts isolated from leaves collected at midday or (3) diurnal and/or circadian regulation of guard cell metabolism over the course of a day.
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  • 46
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    Physiologia plantarum 86 (1992), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The physiological response of cowpea (Vigna sinensis L.) epicotyl explants to far-red light (FR) and its interaction with gibberellins (GAs) have been investigated. The effect of FR and GA1 varied with the age of the seedlings from which the explants were made: for FR, it decreased progressively with age (though the sensitivity of the epicotyls to FR did not change significantly until at least day 11), whereas it remained essentially constant for applied GA1 between days 5 and 9 after sowing. This indicates that the loss of response to FR may be due to a decrease in endogenous GA levels in the epicotyl. For a range of GA1 and GA20 (0.01–1 µg explant−1), both hormones were more active in FR than in R irradiated epicotyls, suggesting that phytochrome may affect GA sensitivity besides GA metabolism. The location of the epicotyl region most sensitive to FR (between 5 and 20 mm below the apex) was different from that to GAs (the upper 10 mm). Nevertheless, FR extended the region responsive to applied GAs, even in paclobutrazol-treated epicotyls where elongation was due entirely to exogenous GAs. This means that modulation of epicotyl elongation by phytochrome, that occurs in a zone different from though overlapping with the GA-sensitive subapical zone, is also mediated by GAs. Growth in the most FR-sensitive region of the epicotyl stimulated by FR or GA1 was due to cell elongation, and in the most GA-sensitive region to both cell division and elongation. The effect of FR and GA1 was negated by colchicine, indicating that microtubules may be involved in the response to both factors.
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  • 47
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The aim of these animal experiments was to characterize and evaluate the healing-in of root analogue titanium implants fitting with high precision to the alveolar wall. Four beagle dogs were used in the study. The roots of the 3rd and 4th mandibular premolars in both quadrants of 3 dogs and in 1 quadrant of 1 dog (dog 4) were extracted after hemisection. Each root was machine-copied to 1 titanium analogue. In dog 4, however, 2 titanium analogues were fabricated from each of the 4 extracted roots. This enabled insertion of analogues also into the contralateral sockets obtained by extraction of the corresponding roots immediately before implant installation, which was undertaken 2 weeks after the first extractions. Thus, in all, 32 analogues were implanted in their respective (or contralateral) sockets following ridge incision and elevation of mucoperiosteal flaps. The analogues were carefully covered by the repositioned flaps. In dog 4, 2 analogues from the immediate sockets and 2 from the 2-week sockets were surgically exposed and supplied with titanium crowns after a healing period of 2 months. The healing after implantation was evaluated by clinical, radiographic and histological measures after 2, 12 or 36 months. Two analogues (6%) were lost due to early (during the 1st week) exposure to the oral cavity. Another 2 analogues (6%) were, although not exposed, encapsulated by soft tissue and were easily removed with a surgical forceps. Twenty-eight analogues (88%) were healed-in by contact between bone and implant (osseointegration). The mean percentages of bone tissue in contact with the implant of such analogues were 30.5% after 2 months, 64.8% after 12 months and 68.1% after 36 months, as evaluated by histomorphometric analysis. The 4 analogues supplied with titanium crowns carried those with maintained bone anchorage throughout an experimental period of 36 months. The character of the interface between the analogue and the surrounding bone tissue was the same regardless of whether the implantation was performed immediately 1 or 2 weeks after extraction of the roots.
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  • 48
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Hydroxyapatite-coated and uncoated titanium screws were inserted in the rabbit tibial metaphysis and evaluated by histomorphometry after 6 months of follow-up. There was no difference in direct bone contact between the HA-coated implants and the uncoated controls. The effect of HA-coating on screw-shaped implants seems to be uncertain, in contrast to unthreaded cylindrical designs, where there is more abundant documentation in favour of HA-coated implants.
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  • 49
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: 6 mandibles were radiographically examined bilaterally to visualise the mandibular canal. 5 imaging techniques were used: periapical radiography, panoramic radiography, hypocycloidal tomography, spiral tomography and computed tomography (CT). Panoramic radiographs were obtained with 2 different X-ray machines. The CT-examinations comprised direct images and standard reconstructions based on axial slices. The specimens were subsequently sectioned for contact radiography. The visibility of the mandibular canal was estimated by 3 observers at special reference points on all radiographs and classified as clearly visible, questionable visibility or not visible. The contact radiographs served as the “gold standard”. The inter-observer and the intra-observer agreement were assessed by calculating the overall agreement and the x. value. Direct coronal computed tomography, as well as spiral and hypocycloidal tomography, gave better visualisation of the mandibular canal than periapical and panoramic radiography.
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  • 50
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The clinical success of 85 Screw Vent® and 107 Bråemark® implants, consecutively installed in a private periodontal clinic under the same conditions and by the same operator, is compared. Mobile implants were removed and considered as failures. Intraoral radiographs were assessed for the presence of peri-implant radiolucencies and for analysis of bone loss after functional loading. 85 Screw Vent implants were installed in 31 patients. Of 23 implants installed in 9 mandibles, none failed after 16.8 (range 12–25) months of function. Of 62 Screw Vent implants installed in 23 maxillae, 6 failed at abutment connection, 1 failed after 2 months and 2 after 13 months of function. The absolute failure rate after 13.2 (range 6–24) months was 9162. Mean loss of bone was 1.47 mm (-l.O–+4) after 12 months of functional loading. 107 Brånemark fixtures were installed in 25 patients. Of 51 fixtures inserted in 12 mandibles, none failed; of 56 fixtures installed in 13 maxillae 1 failed before and 2 failed during abutment connection. The absolute failure is 3156. All remaining fixtures were immobile after loading. 13 fixtures were more than 6 months in function. Only short-term comparison between both systems is possible because the observation time is longer for the Screw Vent implants. In the 1st year, only 1 implant system was available to the periodontist. Short-term comparison reveals 11.3% versus 5.3% of cumulative failure after 6 months for the Screw Vent and Brånemark implants, respectively. The results indicate that clinical efficacy is as effectively obtained with Screw Vent as with Brånemark implants in the mandible. The outcome of treatment with Screw Vent implants in the maxilla seems less predictable.
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  • 51
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: A dedicated research house is used to investigate the interactions of the house, and atmosphere on indoor radon concentrations. Semi-diurnal variations of atmospheric pressure, resulting from atmospheric tides, are observed to produce differential pres- sures capable of driving radon-containing sail gas into slab-on-grade structures built over low permeability soils. These naturally induced pressure differentials could continue to provide major contributions to radon entry when other sources of house pressurization or depressurization, and consequently outdoor air infiltration rates, are small. The observed driving force pressure differentials are well predicted from atmospheric pressure changes by a simple model based on an exponentially damped response of the sub-slab pressures to changes in atmospheric pressure. The observed radon entry rates are in good agreement with the predictions of radon entry models developed by other investigators when time-averaging of the driving forces is applied.
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  • 52
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The most important features of Tenax and Carbotrap, solid sorbents used widely for sampling organic pollutants in air, have been tested under the conditions requested for surveys in indoor spaces and for determinations of VOC emitted from indoor sources by chamber experiments. The performances of samplers, tested with 10 nonpolar and polar (mostly lipophilic) hydrocarbons, present as vapours in 0.5 to 2.0 litre air samples, include: (a) accuracy and reproducibility of the measured concentration, (b) background or “blank” of samplers, (c) stability upon storage (at ambient and below ambient temperatures) of clean samplers and of samplers loaded with VOC, and (d) performance stability after several sampling desorption cycles. The results fulfil the requirements for both adsorbents, though each presents some different drawbacks. In particular (a) Tenax samplers show a “blank” (90 percentile) of 16 ng of benzene and 5 ng of toluene, Carbotrap samplers roughly twice as much; (b) the samplers may be stored for one month either before or after use and (c) they may withstand many cycles without discernible deterioration.
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  • 53
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The emission charaaaistics of four organic compounds (non-ane, decam, undecane, and 1, 2, 4-trimethylbenzene)from wood stain have been measured in an environmental chamber It was found that the emission patterns of the four organic compounds can be described by a two-phase model. Phase 1 represents the period when the wood stain is relatively wet. Phase 2 is when the wood stain becomes relatively dry. The changes of emission mechanisms between the two phases were reflcted by the significantly different emission rate canstants measured during the two periods and the relationship between the relative rate constant, the relative vapor pressure, and the relative diffusivity. A double-exponential model was established that can be used to predict the relative emission rates of the four organic compounds fiom the wood stain.
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  • 54
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: During the winter of 1988/1989, the relationships between the prevalence of work-related health and indoor climate complaints and a number of building, management, workplace and personal characteristics have been investigated in a study in more than 60 office buildings located throughout the Netherlands.To collect the information, a questionnaire was prepared on health and indoor climate complaints and personal and workplace characteristics. A checklist was used to obtain information on building characteristics More than 7000 questionnaires were completed by the regular users of the buildings investigated.The results showed that the prevalence of symptoms was higher in air-conditioned buildings than in naturally or mechanically ventilated buildings. some other variables were also related with most work-related complaints after adjustment for selected management, personal, workplace and job characteristics. These included gender, work satisfaction in general, presence of allergies and/or respiratory symptoms, and personal control over temperature at the workplace. No differences were found in symptom prevalences between buildings with spray and steam humidification. The combination of air-conditioning and humidification did not lead to further increases in the prevalence of complaints as compared to buildings with only airconditioning or only humidification.
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  • 55
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 56
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: An analysis has been completed of the performance, mechanisms, and costs of alternative technologies for preventing radon entry into the living areas of houses having crawl-space foundations. Sub-membrane depressurization (SMD) is consistently the most effective technique, often providing radon reductions of 80-98% in the living area. It has a relatively high installation cost, but a moderate annual operating cost. Forced crawl-space depressurization is the second most effective, giving reductions of 70-96%. Crawl-space depressurization is less well demonstrated than is SMD, and performance will vary with crawl-space tightness and weather, but it will be a primary option when large radon reductions are needed in buildings with crawl-spaces which are inaccessible for installation of SMD. Crawl-space depressurization has a lower installation cost than SMD, but its operating cost may be three times higher.Natural crawl-space ventilation and forced crawl-space pressurization each typically provides roughly 50% reduction or less in the living area. The lack of a clear benefit of crawl-space pressurization in most installations probably indicates that the crawl space is in fact not being pressurized. Crawl-space sealing and barriers (as stand-alone methods) usually give little or no reduction.
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  • 57
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The purpose of the study was to gather information about the actual ventilation and indoor air quality and to evaluate the differences between houses and apartments with different ventilation systems. A sample of 242 dwellings in the Helsinki metropolitan area was studied over periods of no weeks during the 1988-1989 heating season. The mean air-exchange rates had a high variation (average 0.52 l/h, range 0.07-1.55 l/h). The ASHRAE minimum value of 0.35 l/h was not achieved in 28% of the dwellings. The air-exchange rates were significantly her in the houses than in the apartments (averages 0.45/0.64 l/h, p 〈 0.001); in the natural ventilation systems they, were slightly her than in the mechanical systems. The average temperature in the bedrooms was approximately 22 °C (range 18–27 °C), slightly but significantly higher in the apartment than in the houses. The average dust depositions were higher in the balanced ventilation systems than in the other systems. The median radon concentration was 82 Bq/m3 (range 5-866 Bq/m3); the Finnish target value of 200 Bq/m3 was exceeded in 17% of the houses but in none of the apartment. The measurements indicate that the indoor air quality in Finnish dwellings is not always satisfactory with reference to human health and comfort.
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  • 58
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: The influence of location of airborne particle source, ventilation rate, air inlet size, supply air velocity, air outlet location, and heat source on the dkributiuns of airborne particle concentration and draught risk in an operating room is investigated. The investigation is carried out by using a flow program with the k-E mdel of turbulence. Based on a standard case, five cases, each with one changed parameter, are computed, and the detailed field distributions of air velocity, temperature, airborne particle concentration, and draught risk are presented.The parametric study concludes that, for a better air quality and thermal comfort, it is desirable to use a higher inflow rate, a larger inlet area, and a uniform velocity profile of supply air. Outlet location and heat source have little influence on the disrributions of the particle concentration in the room. It has also been found that the distributions of particle concentration in the recirculating zone are very sensitive to the location of the particle sources.
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  • 59
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    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: Simplified, physical models for calculating infiltration and ventilation in a single zone usually calculate the airflows from the two natural driving forces (i.e., wind and stack effects) separately, and then use a superposition rule to combine them. Similarly, superposition rules may be used to ascertain the effects of mechanical systems on infiltration. In this report a general superposition rule will be derived for combining wind, stack, and mechanical ventilation systems together. The superposition rule will be derived using general principles of leakage dismbution and airflow and will not depend on the details of a particular infiltration model. In the process of generating this rule, a quantity called leakage distribution angle is developed to quantify the separation of areas of the building envelope which are subject to infiltration and exfiltration. The general superposition rule is compared to other proposed superposition rules including those based on measured data, and the general rule is shown to have strong explanatory power Results are generated for typical buildings. The concept of fan addition efficency is developed to determine the effectiveness of unbalanced (mechanical) ventilation systems at augmenting infiltration.
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  • 60
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
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  • 61
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: This article contains a summary discussion of human health effects linked to indoor air pollution (UP) in homes and other non-industrial environments. Rather than discussing the health effects of the many different pollutants which can be found in indoor air, the approach has been to group broad categories of adverse health effects in separate chapters, and describe the relevant indoor exposures which may give rise to these health effects.The following groups of effects have been comdered: effects on the respiratory system; allergy and other effects on the immune system; cancer and effects on reproduction: effects on the skin and mucous membranes in the eyes, nose and throat; sensory effects and other effects on the nervous system; effects on the cardiovascular system; systemic effects on the liver, kidney and gastro-intestinal system. For each of these groups, effects associated with IAP the principal agents and sources, evidence linking IAP to the effects, susceptible groups, the public health relevance, methods for assessment, and major research needs are briefly discussed.For some groups of effects, clear relationships with exposure to IAP have been reported in the world literature. Among these are respiratory disease (particularly among children), allergy (particularly to house dust mites) and mucous membrane irritation (particularly due to formaldehyde). Large numbers of people have been, and are still being affected.Many chemicals encountered in indoor air are known or suspected to cause sensory irritation or stimulation. These, in turn, may give rise to a sense of discomfort and other symptums cummonly reported in so-called “sick” buildings. Camplex mixtures of organic chemicals in indoor air also have the potential to invoke subtle effects on the central and peripheral nervous system, leading to changes in behaviour and performance.An increased risk of developing lung cancer has been linked to exposure to environmental tobacco smoke (ETS) and to radon decay products. Lung cancer is a very serious disease with a high fatality rate; however, the number of people affected is much lower than the number of people contracting resparatory disease or alhgies, or experiencing irritative effects due to exposure to indoor pollution.The effects of IAP on reproduction, cardiovascular disease and on other systems and organs have not been well documented to date. To a certain extent, this may mean that no serious effects occur, but there has been little by way of research to clearly document the absence of these tvpes of effects.
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  • 62
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    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: A two-season survey of indoor 222Rn concentrations was conducted in 226 occupied houses in Roane County, TN, during 1985 and 1986. A similar survey of 86 houses in Madison County, AL, was conducted in 1988 and 1989. Alpha track detectors were placed in each of the houses for three or more months during the winter heating season. Detectors were placed at the same sampling sites during the following cooling season. In this study, comparisons were made between winter and summer sampling times and between building types. For the data from Madison County, additional comparisons were made among regions of the county that differed in geological characteristics, especially the thickness of overburden above the Chattanooga Shale layer a geological stratum that has high concentrations of 226Ra and is widely found in the southeastern United States. The geometric means of summer and winter measurements in Roane County were 33 and 54 Bq m−3, respectively. For Madison County, the summer and winter geometric means were 121 and 88 Bq m−3, respectively. The winter 222Rn concentrations for houses in Roane Coutuy exceeded summer 222Rn concentrations, as is generally the case for houses in the US. For houses in Madison County, we found the opposite and atypical situation of higher 222Rn concentrations in the summertime. 222Rn concentrations differed significantly among groups of houses in distinguishable regions of Madison County. Substructure and other building factors had no observable effect on indoor 222Rn concentrations found in this study.
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  • 63
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    Copenhagen : Munksgaard International Publishers
    Physiologia plantarum 86 (1992), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Daylily (Hemerocallis hybrid cv. Cradle Song) flower development and senescence was categorised into seven stages, each separated by one day. As the bud developed (Stages I to III) its fresh and dry weight increased, but during flower opening (Stages III to IV) only the fresh weight increased, reaching a maximum when the flower was fully open (Stage IV). Fresh and dry weight declined as the flower senesced (Stages V to VII), and the petal tissue became water-soaked. Flower respiration was relatively constant through Stages I to III, but during opening the CO2 production increased, then declined as the flowers senesced. Ethylene production was low throughout flower development, and there was a transient increase, up to 2.5 nl flower−1 h−1, as flowers senesced. Petal protein content per gram fresh weight decreased throughout flower development and senescence either on or off the plant. One-dimensional SDS-PAGE revealed a general gradual loss of protein bands during flower senescence and loss of some specific bands (e.g. at M, 30 000 and 40 000). Flowers, detached from the plant at Stage III, placed in deionised (DI) water for 7 h and then transferred to fresh DI water or actinomycin D (25 mg l−1), showed an increase in fresh weight up to a maximum at about 12 h after transfer, followed by a rapid decline. By 48 h the flowers had completely senesced, the tissue becoming watersoaked and free moisture appearing on the tips of collapsed petals. In contrast, senescence of flowers treated during opening with cycloheximide (1 mM) was greatly delayed, with little loss of fresh weight or reduction in flower diameter, even up to 181 h after transfer. When such flowers did finally senesce, they did not show the same pattern of senescence as seen with those in water or actinomycin D. Cycloheximide-treated flowers wilted gradually and showed no water-soaking and no free moisture at the petal tips. Cycloheximide treatment retarded the decline in protein content of the petals; and the protein population, as visualised by SDS-PAGE, was maintained for up to 204 h after transfer to cycloheximide.
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  • 64
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    Copenhagen : Munksgaard International Publishers
    Physiologia plantarum 86 (1992), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The distribution of phosphoenolpyruvate carboxylase (PEPCase, EC 4.1.1.31) in different leaf-cell-types and tissues of Vicia faba L. cv. 3-fach Weiße was studied. The highest specific PEPCase activity was found in guard cell protoplasts (16.3 µmol mg−1 protein h−1) whereas for epidermal and mesophyll protoplasts remarkably lower specific activities were found (1.6 and 1.0 µmol mg−1 protein h−1, respectively). On chlorophyll and protoplast basis, a similar distribution of enzyme activity was observed. Compared with epidermal extracts, the specific PEPCase activity of mesophyll tissue was 17-fold lower. Immunological studies with polyclonal antibodies to PEPCase indicated 3 immunoreactive proteins in epidermal tissue and guard cell protoplasts with molecular masses of 107 000, 110 000, and 112 000. Only the Mr 107 000 protein was found in extracts of mesophyll and epidermis protoplasts. Western immunoblots after native electrophoresis of epidermal and mesophyll proteins showed a significant difference in PEPCase mobility. It is assumed, that the immunostained proteins of Mr 110 000 and 112 000 represent isoforms or subunits of the PEPCase and that they are involved in stomatal movements.
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  • 65
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    Copenhagen : Munksgaard International Publishers
    Physiologia plantarum 86 (1992), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Seedlings of Scots pine (Pinus sylvestris L.) and Norway spruce [Picea abies (L) Karst.] were subjected to low root temperatures, and 10 days later the roots were examined by NMR imaging. The amount of NMR detectable roots decreased with decreasing temperature, with the signal from the younger roots at the bottom of the container being the first to disappear. The origin of the loss of NMR signal is unclear but may be due to changes in the NMR properties of root water after cold damage. A recent method is discussed for obtaining unbiased estimates of root lengths from a series of total vertical projections; the method is particularly suited to evaluating NMR projection images. Since NMR imaging methods can apparently distinguish between control and cold damaged roots, it may be possible to design more routine applications using low resolution NMR methods.
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  • 66
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Studies of root morphology or root architecture are limited by the problems of observing roots in soil. NMR imaging can preferentially detect the water in roots rather than soil and can therefore produce a map of the distribution of the water in roots, even though there is much more water in the soil than in the roots. The gradient echo imaging technique was shown to detect less signal from water in soil than the more usual spin-echo technique, probably because the signal loss due to magnetic field inhomogeneities was not refocused in the gradient echo experiments. The gradient echo sequence produced images of a water-filled capillary tube in soil and of the main roots of a 31-day-old oat plant, images which had better contrast than those from the spin-echo sequence. The improvement was particularly noticeable in the wetter soils. The finer roots could only be observed in the driest of soil and with the spin-echo sequence. Magnetic field inhomogeneities have a greater effect on thinner roots than on thicker ones, and because the initial signal from thin roots was so small, the additional signal loss due to magnetic field inhomogeneities made the fine roots undetectable with the gradient echo sequence. The problem of loss of perspective associated with projection images was overcome by taking a number of images with different projection planes. By comparing images, a set of (x, y, z) coordinates was obtained for the 4 main roots of a 31-day-old oat plant. Computer graphics methods made it possible to compare the digitised root coordinate data set with the original images, thereby confirming the accuracy of the digitised data.
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  • 67
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    Copenhagen : Munksgaard International Publishers
    Physiologia plantarum 86 (1992), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The effects of (−)jasmonic acid (JA) on germination of embryos isolated from dormant seeds of apple (Malus domestica Borb. cv. Antonówka) cultured in darkness or at 12-h photoperiod were studied, as well as its effects on the activity of alkaline lipase (AlkL, EC 3.1.1.3) in these embryos. The maximum sensitivity of germination to JA occurred on days 3 and 4 of embryo culture. Both germination and enzyme activity were stimulated by JA, its effect being additive to that of light. Inhibitors of lipoxygenase inhibited embryo germination and AlkL activity, both effects being partially reversed by JA treatment. We suggest that (1) JA is implicated in an endogenous complex controlling apple seed germination, and that (2) it acts independently of the mechanism triggered by light.
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  • 68
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Gibberellin A4/7 (GA4/7) was applied twice weekly to 2-year-old Pinus sylvestris (L.) seedlings in each of two years, starting close to budbreak and ending after shoot elongation, but before cambial activity ceased. In 1988, the GA4/7 was injected into the 1987 terminal shoot (0, 0.2 or 2 mg seedling−1 application−1), while in 1990 it was applied as a soil drench (0, 10 or 50 mg seedling−1 application−1). In the 1988 experiment, GA4/7 treatment promoted diameter growth, and tended to increase both longitudinal growth and the indole-3-acetic acid (IAA) level in the 1988 terminal. In the 1990 experiment, GA4/7 treatment increased tracheid production, longitudinal growth, and the cambial region IAA concentration in the 1990 terminal, but did not affect its pith diameter, needle number, needle dry weight, or needle IAA level. Tracheid production in the previous-year's terminal was also promoted in both experiments. The 50 mg GA4/7 soil drench markedly elevated the concentrations of GA4, GA7 and GA9 in the needles and cambial region of the 1990 terminal, while the 10 mg treatment raised the GA4 level in the cambial region, providing evidence that GA4 and GA7 applied to the roots reaches the shoot system. The results support the hypothesis that the exogenous GA4/7-induced stimulation of tracheid production in the terminal shoot of intact plants is mediated through an increase in the IAA level in the cambial region. However, per se activity of GA4, GA7 or their metabolites cannot be ruled out.
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  • 69
    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In 21 individuals, edentulous in the upper jaw, the speech function was evaluated. In an earlier study, registrations were made when the patients wore complete dentures in the upper jaw and 3–6 months after they had been treated with fixed prostheses on osseointegrated implants in the maxilla. These patients were re-examined after 3 years, as reported in this follow-up study. An expert group as well as a non-expert group participated in a perceptual analysis. Acoustic, audiological and cast analyses were performed. In addition, a questionnaire was filled in. The results indicated that, after initial phonetic problems, 94% of the individuals considered themselves free from speech problems at the 3-year follow-up. The patients' experience of the change of the s-sound corresponded well with the judgement of both the expert and the non-expert groups. Difficulties with pronouncing the s-sound were associated with decreased bite force, the number of occluding contacts, the frontal width of the fixed prosthesis and tenderness at palpation of the masticatory muscles. These oral functional factors will contribute to the s-sound production.
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    ISSN: 1600-0501
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The objective of the present experiment was to study lesions in the peri-implant and periodontal tissues resulting from ligature placement and subgingival plaque formation. The experiment was performed in 5 beagle dogs which at the start of the study were about 15 months old. They were given a diet which allowed gross plaque formation. The mandibular right premolars were extracted, 3 fixtures (a.m. Brånemark) installed and abutment connection performed. Towards the end of a 6-month plaque control period, a clinical and radiographic examination was performed. Ligatures were placed in a subgingival position at 2 of the implants and the contralateral premolars. Plaque was allowed to accumulate. After 6 weeks, the ligatures were removed. 1 month later, the clinical and radiographical examination was repeated and samples from the subgingival microbiota obtained. Biopsies from the teeth and implant sites were harvested and processed for histometric and morphometric analyses. The results from the clinical and histological examinations revealed that:(i) clinical and radiographic signs of tissue destruction were more pronounced at implants than at teeth;(ii) the size of the soft tissue lesion was larger at implants than at teeth;(iii) the lesion at implants but 1 not at teeth extended into the bone marrow.
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