Penetration of hydrogen isotopes through the superalloy ÉI698 at high pressures and temperatures

Conclusions We determined the parameters of the processes of penetration and diffusion of the hydrogen isotopes through the superalloy ÉI698 in the 600–1050°K range at pressures up to 100 MPa. It was shown that the penetrating flux is in proportional to p in the 0.1–100 MPa pressure range.The diffusion coefficient of hydrogen (deuterium) does not depend on the concentration of the dissolved hydrogen (deuterium) that attains a value of 1.3·10⁶ cm³/cm³ Me at a pressure of 100 MPa and a temperature of 1050°K. The concentration of the dissolved hydrogen is not critical with respect to hydrogen-embrittlement of the ÉI698 alloy subjected to loading for a period of 600 h under an internal pressure of 100 MPa. Based on the obtained values of the penetration rates of hydrogen and deuterium through the ÉI698 alloy, the decrease in the quantity of the gas in the vessel can be taken into account properly when carrying out experimental studies on the processes of mu-catalysis.Translated from Atomnaya Énergiya, Vol. 65, No. 6, pp. 395–399, December, 1988.     

A benign form of chronic lympholeukemia]

According to the classification of chronic lymphocytic leukemia (CLL) proposed by A. I. Vorob'ev and M. D. Brilliant in 1983, benign CLL is a distinct form of CLL which is characterized by low level of absolute lymphocytosis, absent or mild peripheral lymphadenopathy, slow progression. No specific therapy is needed. The paper presents clinical, morphological and immunological analysis of 34 cases of benign CLL (17 males and 17 females, mean age 58 years). Patients were included in the study if they had lymphocyte count less than 30,000 and no significant growth of lymphoid tissue for at least 3 years. They were followed up from 3 to 24 years (11 years, on the average). The main features of benign CLL are the following: no "B" symptoms, no essential enlargement of the lymphoid organs, a stable low level of absolute lymphocytosis, low prolymphocyte count in the blood smear (0.95% +/- 0.2), nodular or nodular-interstitial proliferation in the bone marrow. We failed to find any cases with paraprotein secretion. There was immunophenotype typical for CLL in 91% of cases (CD19+, CD20+, CD23+, CD5+, EM+, CR1-/CR2+, sIg+(-)). None was positive for CD38 activation marker. One trisomy 12 cases was detected by FISH method. 8 patients died so far, but not because of the tumor progression or transformation, median survival was 22 years.     

Sites of selective cAMP-dependent phosphorylation of the L-type calcium channel alpha 1 subunit from intact rabbit skeletal muscle myotubes

The principal (alpha 1) subunit of purified skeletal muscle dihydropyridine-sensitive (L-type) calcium channels is present in full-length (212 kDa) and COOH-terminal truncated (190 kDa) forms, which are both phosphorylated by cAMP-dependent protein kinase (cA-PK) in vitro. Immunoprecipitation of the calcium channel from rabbit muscle myotubes in primary cell culture followed by phosphorylation with cA-PK, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and two-dimensional phosphopeptide mapping revealed comparable phosphorylation of three COOH-terminal phosphopeptides found in the purified full-length alpha 1 subunit. Stimulation of muscle myotubes with a permeant cAMP analogue, 8-(4-chlorophenylthio) adenosine 3',5'-cyclic monophosphate, prior to immunoprecipitation of alpha 1 results in a 60-80% reduction of cA-PK catalyzed "back" phosphorylation of each of these sites in vitro in calcium channels purified from the cells, indicating that these sites are phosphorylated in vivo in response to increased intracellular cAMP. Serine 687, the most rapidly phosphorylated site in the truncated 190-kDa alpha 1 subunit, was observed as a minor phosphopeptide whose level of phosphorylation was not significantly affected by stimulation of endogenous cA-PK in the myotubes. The COOH-terminal sites, designated tryptic phosphopeptides 4, 5, and 6, were identified as serine 1757 (phosphopeptides 4 and 6) and 1854 (phosphopeptide 5) by a combination of protease cleavage, phosphorylation of synthetic peptides and fusion proteins, specific immunoprecipitation, and phosphopeptide mapping. Phosphorylation of serines 1757 and 1854 in the COOH-terminal region of the 212-kDa alpha 1 subunit in intact skeletal muscle cells may play a pivotal role in the regulation of calcium channel function by cA-PK.     

Inducible NO synthase II and neuronal NO synthase I are constitutively expressed in different structures of guinea pig skeletal muscle: implications for contractile function

The expression of NOS isoforms was studied in guinea pig skeletal muscle at the mRNA and protein level, and the effect of NO on contractile response was examined. Ribonuclease protection analyses demonstrated NOS I and NOS II mRNAs in diaphragm and gastrocnemius muscle. In Western blots, NOS I and NOS II immunoreactivities were found in the particulate but not the soluble fraction of skeletal muscle. NOS activity was found almost exclusively in the particulate fraction. About 50% of this activity was Ca2+ independent. In immunohistochemistry, the anti-NOS I antibody stained distinct membrane regions of muscle fibers. The most intense staining was seen in neuromuscular endplates identified by labeling with alpha-bungarotoxin. The anti-NOS II antibody labeled muscle fibers that contained alkali-labile myosin ATPase (type I fibers). NOS II was located to intracellular structures and was also seen in "specific pathogen-free" animals. Pretreatment of guinea pigs with bacterial lipopolysaccharide (LPS) markedly intensified NOS II staining. Significant NOS III immunoreactivity was detected only in vascular endothelium. In functional experiments, tetanic muscle contractions were induced in diaphragm and gastrocnemius muscle by electrical stimulation of the innervating nerves. Pretreatment of guinea pigs with LPS or addition of S-nitroso-N-acetyl-D,L-penicillamine to the organ bath markedly decreased tetanic contractions. N(G)-nitro-L-arginine, on the other hand, increased contractile force and reversed the effect of LPS. Our data indicate that NOS II and NOS I are expressed in different structures of skeletal muscle and are involved in the regulation of contractile response.     

Impact and biocompatibility studies on Mg2+-substituted Apatite-derived 3D porous scaffolds for hard tissue engineering

The objective of this study was to develop Mg²⁺-substituted Apatite scaffolds by slip-casting method. The Apatite scaffolds were prepared as engineering constructs with interconnected pore structure with a pore size of 128-194 μm range. The physicochemical properties such as crystalline phase, functional group, microstructure, pore size distribution, and elemental compositions of the scaffolds were characterized. The bioactivity of the developed porous scaffolds was investigated in Simulated Body Fluid (SBF) for various time periods (3 and 7 days). In vitro bioactivity results confirm the hydroxyl Apatite layer formation of the scaffolds and results suggest that the developed microporous scaffold could be used as suitable candidates in bone tissue engineering.     

Hydrogen and hydrocarbon interaction with plasma-facing materials of thermonuclear facilities

The modeling of hydrocarbon radical transport and deposition in the pumping ducts of thermonuclear facilities is overviewed, and hydrogen isotopes accumulation in beryllium and its compounds is analyzed. Special features of the hydrogen permeability of metals under conditions of facing plasma, as well as behavior of boron-hydrogen films used as protecting coatings in operating tokamaks, are discussed. Original Russian Text ? V.Kh. Alimov, A.E. Gorodetsky, R.Kh. Zalavutdinov, A.P. Zakharov, V.M. Sharapov, 2007, published in Zashchita Metallov, 2007, Vol. 43, No. 6, pp. 565–588.     

MODELLING OF THE DRYING PROCESS OF WOOD IN 3-DIMENSIONS

The process of drying parallelepipedic samples of wood is studied, by considering 3-dimensional transport of water along the 3 principal axes of diffusion, as well as evaporation out of the surface. During a large part of the process, the water content is considerably higher than the value associated with the fiber saturation point. A numerical model with finite differences, based on the assumption that the transport of water is controlled by transient diffusion through the sample and evaporation from the surface, is successfully tested with a beam in the following two cases : the initial concentration of water is uniform, or not. The model is capable of predicting not only the kinetics of drying, but also the profiles of concentration developed through the samples at various times. The principal diffusivities are determined by using a short test technique in transient condition.