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  • 1
    ISSN: 1432-1238
    Keywords: Key words Nitric oxide ; Distribution ; Uptake ; Monitoring ; ARDS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Objectives : The concentrations of nitric oxide (NO) in the ventilatory circuits and the patient's airways were compared between sequential (SQA) and continuous (CTA) administration during inspiratory limb delivery. Design: Prospective controlled study. Setting: 14-bed Surgical Intensive Care Unit of a teaching University hospital. Patients and participants: Eleven patients with acute lung injury on mechanical ventilation and two healthy volunteers. Interventions: A prototype NO delivery device (Opti-NO) and César ventilator were set up in order to deliver 1, 3 and 6 parts per million (ppm) of NO into the bellows of a lung model in SQA and CTA. Using identical ventilatory and Opti-NO settings, NO was administered to the patients with acute lung injury. Measurements and results: NO concentrations measured from the inspiratory limb [INSP-NOMeas] and the trachea [TRACH-NOMeas] using fast response chemiluminescence were compared between the lung model and the patients using controlled mechanical ventilation with a constant inspiratory flow. INSP-NOMeas were stable during SQA and fluctuated widely during CTA (fluctuation at 6 ppm = 61 % in the lung model and 58 ± 3 % in patients). In patients, [TRACH-NOMeas] fluctuated widely during both modes (fluctuation at 6 ppm = 55 ± 3 % during SQA and 54 ± 5 % during CTA). The NO flow requirement was significantly lower during SQA than during CTA (74 ± 0.5 vs 158 ± 2.2 ml.min–1 to attain 6 ppm, p = 0.0001). INSP-NOMeas were close to the values predicted using a classical formula only during SQA (bias = –0.1 ppm, precision = ± 1 ppm during SQA; bias = 2.93 ppm and precision = ± 3.54 ppm during CTA). During SQA, INSP-NOMeas varied widely in healthy volunteers on pressure support ventilation. Conclusions: CTA did not provide homogenous mixing of NO with the tidal volume and resulted in fluctuating INSP-NOMeas. In contrast, SQA delivered stable and predictable NO concentrations during controlled mechanical ventilation with a constant inspiratory flow and was economical compared to CTA. However, SQA did not provide stable and predictable NO concentrations during pressure support ventilation.
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  • 2
    ISSN: 1432-0630
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: 1-x CaxMnO3 films under the influence of temperature, topographic sample defects and external magnetic field. At low temperatures, typically about 140 degrees below Tc=245 K, domains were strongly coupled to each other, but could still be affected by thermal fluctuations. As we warmed the sample up, domains became highly mobile near Tc. Near Tc, sample scratches were able to capture nearby domains, whereas they did not affect domains when temperature is much lower than Tc. Above Tc all domains disappeared, with some of them disappearing earlier.
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  • 3
    ISSN: 1432-0630
    Keywords: 75.60.Jp ; 75.30.Gw
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The iron granular solid, in which ultrafine iron particles are dispersed, has been prepared with both SiO2 and Cu matrices using the sol-gel method. The structure and morphology of these granular solid samples are investigated by X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The magnetic properties are measured using a vibrating sample magnetometer with 20 kOe maximum applied field. It is found that the coereivity decreases very slightly with temperature from 80 to 300 K for these Fe−SiO2 and Fe−Cu granular solid samples with different average size of iron particles from 50 to 300 Å. The magnetic anisotropy has been obtained from the measured magnetization curves for these granular solid samples using the law of approach to saturation, and the obtained values of the effective magnetic anisotropy are all more than 106 erg/cm3, which are larger than the value of the magnetocrystalline anisotropy for bulk iron. The coercivity vs temperature for these granular solid samples has been calculated using the Kneller and Luborsky theory, in which the magnetic anisotropy values obtained from the law of approach to saturation are used. The trends of the calculated coercivity as a function of temperature are in reasonable agreement with the observations.
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  • 4
    ISSN: 1432-0630
    Keywords: PACS: 75.60.Jp; 75.30.Gw
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract.  The iron granular solid, in which ultrafine iron particles are dispersed, has been prepared with both SiO2 and Cu matrices using the sol-gel method. The structure and morphology of these granular solid samples are investigated by X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The magnetic properties are measured using a vibrating sample magnetometer with 20 kOe maximum applied field. It is found that the coercivity decreases very slightly with temperature from 80 to 300 K for these Fe–SiO2 and Fe–Cu granular solid samples with different average size of iron particles from 50 to 300 AÅ. The magnetic anisotropy has been obtained from the measured magnetization curves for these granular solid samples using the law of approach to saturation, and the obtained values of the effective magnetic anisotropy are all more than 106 erg/cm3, which are larger than the value of the magnetocrystalline anisotropy for bulk iron. The coercivity vs temperature for these granular solid samples has been calculated using the Kneller and Luborsky theory, in which the magnetic anisotropy values obtained from the law of approach to saturation are used. The trends of the calculated coercivity as a function of temperature are in reasonable agreement with the observations.
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  • 5
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Based on the variational-cumulant expansion (VCE), a new approach is adopted to determine the critical couplings for the deconfinement phase transition in SU(2) gauge theory for $N_\tau=2,3,4$ , and with both the standard Wilson action and the improved tree-level Symansik action. New results of the VCE which are close to the data of Monte Carlo (MC) simulations make manifest that the new approach is much more effective than the traditional one and show the consistence of a VCE analysis with an MC simulation.
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  • 6
    ISSN: 1434-6079
    Keywords: PACS. 32.70.Cs Oscillator strengths, lifetimes, transition moments - 32.80.Hd Auger effect and inner-shell excitation or ionization - 32.80.Fb Photoionization of atoms and ions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: Extensive configuration interaction wave functions are determined to calculate the energies of the inner-shell excited states and the oscillator strengths of the optically allowed inner-shell transitions of C IV ion. Photoionization cross-sections of the ground and the first excited states of C IV ion are also obtained by using the R-matrix method. The positions of some inner-shell excited states are redetermined more accurately by analyzing the resonance structures of the photoionization processes. Some of the results are compared with other available theories and experiments.
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  • 7
    ISSN: 1617-4623
    Keywords: Key words Proline dehydrogenase cDNA ; Prolineoxidase ; Transcriptional regulation ; Osmotic stress ; Arabidopsis thaliana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Plants generally accumulate free proline under osmotic stress conditions. Upon removal of the osmotic stress, the proline levels return to normal. In order to understand the mechanisms involved in regulating the levels of proline, we cloned and characterized a proline dehydrogenase (PDH) cDNA from Arabidopsis thaliana (AtPDH). The 1745 bp cDNA contains a major open reading frame encoding a peptide of 499 amino acids. The deduced amino acid sequence has high homology with both Saccharomyces cerevisiae and Drosophila melanogaster proline oxidases and contains a putative mitochondrial targeting sequence. When expressed in yeast, the AtPDH cDNA complemented a yeast put1 mutation and exhibited proline oxidase activity. We also determined the free proline contents and the Δ1-pyrroline-5-carboxylate synthetase (P5CS) and PDH mRNA levels under different osmotic stress and recovery conditions. The results demonstrated that the removal of free proline during the recovery from salinity or dehydration stress involves an induction of the PDH gene while the activity of P5CS declines. The reciprocal regulation of P5CS and PDH genes appears to be a key mechanism in the control of the levels of proline during and after osmotic stress. The PDH gene was also significantly induced by exogenously applied proline. The induction of PDH by proline, however, was inhibited by salt stress.
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  • 8
    ISSN: 1573-7217
    Keywords: aromatase ; biochemical activity ; intratumoural ; immunohistochemistry ; response
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The role of intratumoural aromatase in human breast cancer growth remains controversial. At the same time as the use of aromatase inhibitors in the clinical setting continues to increase, so does the need for a tool to predict the likely response to this treatment. Intratumoural aromatase is a candidate predictive marker. The presently accepted 'gold standard' methods of assessment of aromatase activity are biochemical assays. However, these are time-consuming and require relatively large amounts of fresh or frozen tissue which are frequently not available. The development of a reliable immunohistochemical technique for the assessment of intratumoural aromatase which could be applied rapidly to more readily available paraffin-embedded material is therefore highly desirable. Unfortunately aromatase immunohistochemistry is also an area of controversy; some authors describe localisation to the stromal compartment but others to the malignant epithelial cells themselves. The aim of this study was therefore to compare immunohistochemical scores using two different antibodies with biochemical aromatase activity. Taking a group of 29 human breast carcinomas we demonstrated a strong correlation between immunoreactivity with a monoclonal antibody (p = 0.01) but not with a polyclonal (p = 0.16). The monoclonal produced reactivity in both epithelial and stromal cells but the polyclonal in only stromal cells. The implications of these results are discussed together with the need for further studies.
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  • 9
    ISSN: 1432-1238
    Keywords: Key words Adult respiratory distress syndrome ; Outcome ; Computed tomography ; Lung morphology ; Lung mechanics ; Lung volumes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objectives: (a) To assess whether differences in lung morphology observed in patients with adult respiratory distress syndrome (ARDS) are associated with differences in cardiorespiratory parameters, lung mechanics, and outcome. (b) To propose a new ARDS Severity Score to identify patients with a high mortality risk. Design: Prospective study over a 53-month period. Setting: Fourteen-bed surgical intensive care unit of a university hospital. Patients and participants: Seventy-one consecutive patients with early ARDS. Measurements and results: Cardiorespiratory parameters were measured using a Swan-Ganz catheter, the pressure-volume (PV) curve was measured using the gross syringe method, and fast spiral computed tomography (CT) was performed. Patients with diffuse attenuations (n = 16) differed from patients with lobar attenuations (n = 26) regarding: (a) mortality rate (75 % vs. 42 %, p = 0.05), (b) incidence of primary ARDS (82 % vs. 50 %, p = 0.03), (c) respiratory compliance (47 ± 12 vs. 64 ± 16 ml per cmH2O–1 p = 0.04), and (d) lower inflexion point (8.4 ± 2.0 vs. 4.6 ± 2.0 cmH2O, p = 0.001). A third group of patients with patchy attenuations (n = 29) had a mortality rate of 41 %, a respiratory compliance of 56 ± 18 ml per cmH2O–1 and a lower inflexion point of 6.3 ± 2.7 cmH2O. The bedside chest radiograph accurately assessed lung morphology in only 42 % of the patients. In contrast to the scores based on the bedside chest radiograph, a new ARDS Severity Score based on CT lung morphology and cardiorespiratory parameters identified a subgroup of patients with a high mortality rate (≥ 60 %). Conclusions: In patients with ARDS, differences in lung morphology are associated with differences in outcome and lung mechanics. A new ARDS Severity Score based on CT lung morphology and cardiorespiratory parameters accurately identified patients with the most severe forms of ARDS and a mortality rate above 60 %.
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  • 10
    ISSN: 1573-4935
    Keywords: Transmembrane Ca2+ gradient ; anion transport activity ; Band 3 ; freeze-fracture ; resealed erythrocyte ghosts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The role of a transmembrane Ca2+ gradient in anion transport by Band 3 of human resealed erythrocyte ghosts has been studied. The results show that a transmembrane Ca2+ gradient is essential for the conformation of erythrocyte Band 3 with higher anion transport activity. The dissipation of the transmembrane Ca2+ gradient by the ionophore A23187 inhibits the anion transport activity. The extent of this inhibition approaches 90% as the Ca2+ concentration on both sides of the ghost membrane is increased to 1.0 mM and half-maximum inhibition is observed at 0.25 mM Ca2+. Addition of ATP (0.4 mM) to the resealing medium can partly reestablish the transmembrane Ca2+ gradient by activation of Ca2+-ATPase and alleviate the inhibition to some extent. N-ethylmaleimide, an inhibitor of erythrocyte Ca2+-ATPase, prevents such restoration. Electron micrographs reveal that numerous larger intramembranous particles can be observed on the P-faces of freeze-fractured resealed ghosts in the absence of a transmembrane Ca2+ gradient.
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