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  • 1
    ISSN: 1433-0350
    Keywords: Key words Quantitative measurement ; CSF flow dynamic ; Phase-contrast cine MR ; Hydrocephalus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  This investigation was undertaken to characterize CSF flow at the level of the aqueduct of Sylvius with a phase-contrast cine MR pulse sequence in 28 healthy volunteers. Sixteen patients with obstructive hydrocephalus and 11 patients with normal pressure hydrocephalus (NPH) were investigated with the same sequence before and after CSF diversion. The peak CSF flow velocity and stroke volume in the aqueduct increased significantly in the NPH group and decreased significantly in the obstructive hydrocephalus group. After lumboperitoneal shunting in the NPH group, the retrograde flow of CSF was anterogradely converted and the peak flow velocities decreased somewhat. The clinical diagnosis of NPH was well correlated with the results of cine MRI. After endoscopic III ventriculostomy in the obstructive hydrocephalus group we noted increased CSF flow velocity with markedly increased stroke volume at the prepontine cistern. Phase-contrast cine MR is useful in evaluating CSF dynamics in patients with hyperdynamic aqueductal CSF or aqueductal obstruction.
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  • 2
    ISSN: 1433-0350
    Keywords: Key words Hydrocephalus model ; Kaolin ; Micro-balloon ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We used three types of specialized micro-balloons 0.7–1.35 mm in outer diameter instead of kaolin to develop a reproducible rat model of hydrocephalus with a low experimental mortality. The micro-balloon was inserted 6 mm deep into the cisterna magna via a burr hole immediately behind the lambda. The angle of introduction was 50°. We also set up kaolin-induced hydrocephalic models in 25 rats as controls. The kaolin model revealed 52% mortality with an 80% induction rate of hydrocephalus, while the balloon model showed 9% mortality with a 60% induction rate. Balloon-induced hydrocephalus was maximal at 1 week and tended to decrease after 2–3 weeks. The pathological findings were not different between the two models. We concluded that the micro-balloon model for hydrocephalus is an easily reproducible model with low experimental mortality.
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  • 3
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Biofilm formation by bacterial cells can be used to modify the subsurface permeability for the purpose of microbial enhanced oil recovery, bio-barrier formation, and in situ bioremediation. Once injected into the subsurface, the bacteria undergo starvation due to a decrease in nutrient supply and diffusion limitations in biofilms. To help understand the starvation response of bacteria in biofilms, the relationship between exopolymer formation and cell culturability was examined in a batch culture. The average cell diameter was observed to decrease from 0.8 μm to 0.35 μm 3 days after starvation began. Cell chain fragmentation was also observed during starvation. Cells that underwent starvation in the presence of insoluble exopolymers showed a slower rate of decrease in cell diameter and in cell chain length than cells without insoluble exopolymers. The rate of decrease in the average cell diameter and cell chain length were determined using a first order decay model. Cells starved in the presence of exopolymers showed greater culturability than cells starved without exopolymers. After 200 days starvation, 2.5 × 10−3% cells were culturable, but no increase in cell number was observed. During starvation, the exopolymer concentration remained constant, an indication that the exopolymer was not consumed by the starving bacteria as an alternative carbon or energy source.
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  • 4
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A chitinase gene (chiA) from Pseudomonas sp. YHS-A2 was cloned into Escherichia coli using pUC19. The nucleotide sequence determination revealed a single open reading frame of chiA comprised of 1902 nucleotide base pairs and 633 deduced amino acids with a molecular weight of 67,452 Da. Amino acid sequence alignment showed that ChiA contains two putative chitin-binding domains and a single catalytic domain. Two proline-threonine repeat regions, which are linkers between catalytic and substrate-binding domains in some cellulases and xylanases, were also found. From E. coli, ChiA was purified 12.8-fold relative to the periplasmic fraction. The Michaelis constant and maximum initial velocity for p-nitrophenyl-N,N′-diacetylchitobiose were 1.06 mM and 44.4 μmol/h per mg protein, respectively. The purified ChiA binds not only to colloidal chitin but also to other substrates (avicel, chitosan, and xylan), but the binding affinity of avicel, chitosan, and xylan is around 10 times lower than that of colloidal chitin. The reaction of ChiA with colloidal chitin and chitooligosaccharides (trimer-hexamer) produced an end product of N,N′-diacetylchitobiose, indicating that ChiA is a chitobiosidase.
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  • 5
    ISSN: 1432-069X
    Keywords: Keywords HSP70 ; Human melanoma cells ; Ultraviolet B ; Apoptosis ; Caspase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The heat shock response is a highly conserved reaction common to all cells and organisms. It has been reported that hyperthermic treatment can induce the expression of the heat shock protein (HSP) and can protect cells from ultraviolet (UV) B radiation. In this study, we evaluated the effects of induced HSP70 on resistance to UV radiation. G361 amelanotic human melanoma cells were irradiated with increasing doses of UVB. UVB irradiation caused apoptotic cell death in these cells. Following transfection with MFG.hsp70.puro plasmid, the expression of HSP70 was determined. Compared to control vector-transfected cells, hsp70-transfected cells showed significantly elevated levels of HSP70 and were highly resistant to UVB irradiation. In order to investigate the effects of HSP70 on the apoptotic pathway, the changes in caspase-3 and PARP were analyzed. Following UVB irradiation, activation of caspase-3 and cleavage of PARP were observed in control vector-transfected cells, and the changes in these molecules were inhibited in the hsp70-transfected cells. These results suggest that UVB-induced apoptosis of melanoma cells is accompanied by caspase-3 activation and PARP cleavage, which can be prevented by an overexpression of HSP70.
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  • 6
    ISSN: 1434-4726
    Keywords: Neuroendocrine carcinoma ; Paranasal sinuses ; Radiation therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The paranasal sinuses are a rare site for neuroendocrine carcinoma (NEC). In contrast to the other regions, NEC of the sinuses has been reported to be recurrent and locally destructive. We report a case of NEC of the ethmoid sinuses. The patient was a 16-year-old Indian boy and was treated with radiation therapy to 6500 rad. He has been disease free for the past 5 years. All the cases reported to date were also reviewed.
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  • 7
    ISSN: 0178-515X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The optimum pH conditions of Pb2+ accumulation in Saccharomyces cerevisiae and Aureobasidium pullulans were 4∼5 and 6∼7, respectively. The initial Pb2+ accumulation rates according to the increase of initial Pb2+ concentration and pH were increased both in S. cerevisie and A. pullulans. And the initial Pb2+ accumulation rate of A. pullulans was much higher than that of S. cerevisiae because of the difference of Pb2+ accumulation mechanism. The Pb2+ accumulation isotherm of S. cerevisae obeyed a fully competitive inhibition, whereas that of A. pullulans showed a mixed inhibition of competition and non-competition associated with the proton (H+) as an accumulation inhibitor.
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  • 8
    ISSN: 0178-515X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  Pb2+ accumulation in Saccharomyces cerevisiae changed by Hg2+ and cell conditions. The accumulated Pb2+ amounts decreased from 0.22 to 0.02 mmol Pb2+/g cell dry weight by the existence of Hg2+. But the total metals accumulation (0.42 mmol metal ions/g cell dry weight) was not changed. The order of accumulated Pb2+ amounts (mg Pb2+/g cell dry weight) according to the cell conditions at an equilibrium state was shown as the original cell (260) 〉 5 times autoclaved cell for 15 min (150) 〉 grinded cell after drying (100) 〉 autoclaved cell for 5 min (30).
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  • 9
    ISSN: 0178-515X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract In Pb2+ accumulation by Aureobasidium pullulans, the time to reach an equilibrium state was not dependent on the initial cell dry weight. The Pb2+ accumulation capacity was increased from 56.9 to 215.6 mg Pb2+/g cell dry weight as the biomass was stored from 1 to 53 days, and correlated with the amount of excreted extracellular polymeric substances (EPS). It was observed that Pb2+ accumulated only on the surface of the intact cells of A. pullulans due to the existence of EPS, whereas Pb2+ penetrated into the inner cellular parts of the EPS-extracted cells.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Bioprocess engineering 22 (2000), S. 533-537 
    ISSN: 0178-515X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The objectives of this study were twofold: to determine the specific oxygen consumption rate of mixed sludges by means of a respirometry study, and to investigate the applicability of a developed model to a pilot-scale reactor containing nightsoil and brewery sludges. The results of the study revealed the specific oxygen consumption rates to be 87.7 mg O2/kg VS-hr and 117.7 mg O2/kg VS-hr at temperatures of 25 °C and 35 °C, respectively. Oxygen was found to be consumed at a higher rate in the reactor operated at the higher temperature. The computer simulation for temperature variations in the pilot-scale reactor showed a good relationship between the simulated and the measured temperatures. After three days operation, the highest simulated temperature was 65 °C, whereas the highest measured temperature was 60 °C. In addition, results suggest that the model can provide an accurate air supply rate to indicate economical reactor operation.
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