Cyclosporine protects glomeruli from FSGS factor via an increase in glomerular cAMP

Cyclosporine (CsA) administration to patients with recurrent focal segmental glomerulosclerosis (FSGS) after transplantation results in remission of proteinuria. We have shown that sera from patients with recurrent FSGS can increase the glomerular albumin permeability (Palbumin) and that increase in glomerular cAMP levels can alter the permeability characteristics of glomeruli in vitro. The purpose of this study was to determine if the increased glomerular levels of cAMP were related to the protective effects of CsA on an increase in Palbumin by FSGS sera. Glomeruli from Sprague-Dawley rats following intraperitoneal administration of CsA (25 mg/kg/day), cremophore (25 mg/kg/day), or saline for 5 days were incubated with 1:50 dilution of serum from three FSGS patients or with pooled normal human serum prior to calculation of Palbumin. Glomerular cAMP was measured by radioimmunoassay. Glomerular ultrastructural changes were assessed by transmission electron microscopy (TEM). Serum from three FSGS patients markedly increased Palbumin of glomeruli from saline or cremophore treated rats (saline, 0.68+/-0.08; 0.72+/-0.07; 0.70+/-0.07; and cremophore, 0.79+/-0.05; 0.81+/-0.02; 0.79+/-0.01; n=25 glomeruli in each group). In contrast Palbumin of glomeruli from CsA treated rats was not increased by any of the three FSGS sera tested (0.03+/-0.02; 0.04+/-0.05; 0.02+/-0.07, n=25 glomeruli in each group). Glomerular cAMP (pmol/mg of protein) increased 5 fold in CsA treated rats (328+/-26; 5 rats) compared with cremophore or saline treated rats (87+/-24 and 65+/-23, P<0.01; 5 rats in each group). The glomerular basement membrane appeared to be thickened and the lamina densa had an irregular appearance after treatment with CsA. No ultrastructural changes of glomerular epithelial or endothelial cells were evident. We conclude that CsA may have a direct protective effect on the glomerular filtration barrier in FSGS. We postulate that increased levels of glomerular cAMP by CsA may play an important role in protecting the glomerular Palbumin effect of the FSGS factor and may contribute to remission of proteinuria in FSGS patients.     

Use of glycidyls in the modification of polyurethane membrane structures

Aromatic glycidyl ethers have been used for modifying the structure of polyurethane membranes and improving their properties. The changes of chemical structure of the polyurethane in the membrane network have been followed by IR spectroscopy. The structural uniformity of the membrane has been elucidated by osmotic measurements and SEM. The structure of the membranes obtained has been related to their permeability towards distilled water.     

Étude expérimentale sur le fluage du béton. Vérification du principe de superposition

Résumé Une étude expérimentale ayant pour but de vérifier le principe de superposition a été effectuée sur des éprowettes de béton soumises à des contraintes permanentes de compression. Une série d'éprouvettes a été chargée sous une contrainte σ à 7 jours, une autre sous la même contrainte à 28 jours et une troisième série d'éprouvettes chargée de 7 jours à 28 jours sous une contrainte σ, la contrainte étant ensuite doublée. L'étude des déformations après 1 700 jours de chargement sous trois contraintes (25, 50 et 75 bar), a été effectuée. L'interprétation des résultats prenant en compte les différentes sortes d'imprécisions expérimentales conduit à la vérification du principe de superposition de Boltzmann, bien qu'une différence de 10% existe entre la théorie et l'expérience.

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Summary Experiments to check the principle of superposition have been carried out on concrete test pieces subjected to permanent compressive stresses. A series of test pieces was loaded under a stress σ for 7 days another under the same stress for 28 days and a third series tras loaded from 7 to 28 days under a stress σ, the stress there being doubled for 28 days. Deformation after 1,700 days loading was measured under three stresses (25, 50 and 75 bar). The Boltzmann principle of superposition is proved valid by interpretation of results taking into account the different types of testing inaccuracies although there remained a difference, of 10% between theory and test figures.

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Ing. école polytechnique féminine, Stagiaire à la Direction de la Recherche de l'UTI.     

Estimating monitoring reliability when the measurement error is dependent on a work-piece parameter

Component parameter monitoring reliability is estimated when the errors of measurement are dependent on the parameters. The solution amounts to a standard classical evaluation of monitoring reliability with statistical independence between the errors of measurement and the parameters.Translated from Izmeritel'naya Tekhnika, No. 2, pp. 10–12, February, 1994.     

Investigation of the hydrodynamics in the near-wall boundary layer of a semi-infinite jet

The velocity profiles and friction stresses at the wall in a semi-infinite jet are investigated.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 17, No. 4, pp. 733–736, October, 1969.     

Impact of phosphorus gettering parameters and initial iron level on silicon solar cell properties

We have studied experimentally the effect of different initial iron contamination levels on the electrical device properties of p‐type Czochralski‐silicon solar cells. By systematically varying phosphorus diffusion gettering (PDG) parameters, we demonstrate a strong correlation between the open‐circuit voltage (V_oc) and the gettering efficiency. Similar correlation is also obtained for the short‐circuit current (J_sc), but phosphorus dependency somewhat complicates the interpretation: the higher the phosphorus content not only the better the gettering efficiency but also the stronger the emitter recombination. With initial bulk iron concentration as high as 2 × 10¹⁴ cm⁻³, conversion efficiencies comparable with non‐contaminated cells were obtained, which demonstrates the enormous potential of PDG. The results also clearly reveal the importance of well‐designed PDG: to achieve best results, the gettering parameters used for high purity silicon should be chosen differently as compared with for a material with high impurity content. Finally we discuss the possibility of achieving efficient gettering without deteriorating the emitter performance by combining a selective emitter with a PDG treatment. Copyright © 2012 John Wiley & Sons, Ltd.     

Transition to film boiling of helium under stepped thermal loading

The results of an experimental investigation of the transition to film boiling of helium under stepped thermal loading, obtained in a wide range of pressures, are presented.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 48, No. 4, pp. 551–554, April, 1985.