The Study of a Proportional Chamber in the Plasma Mode for the Electromagnetic Calorimeter

The proportional chambers operating in the plasma mode were investigated with the aim of being used in calorimetric measurements. The chambers, simple in design, were blown through with a cheap two-component mixture. Amplitude spectra of the showers produced by 10-GeV electrons were measured with lead plates of differing thicknesses. The chambers were investigated in the absence and presence of the magnetic field aligned with their electric field. The experimental results show that this type of detectors can be used to measure the energy of -quanta.     

Thermoelectric Properties of n-Mg2(SiGe)0.8Sn0.2 Solid Solution

Semiconductors - High values of the thermoelectric figure of merit (ZT = 1.5) in Mg2Si–Mg2Sn solid solutions are caused by a low thermal conductivity and a complex band structure, which is...     

Mechanisms of Molding,Phase Formation,and Structuring of Materials Based in Titanium Borides under the Conditions of Combustion Processes and High-Temperature Shear Deformation

Journal of Engineering Physics and Thermophysics - By the method of x-ray diffraction with a high time resolution, the authors have investigated the phase formation and structuring of titanium...     

Hernia development in CAPD patients and the effect of 2.5 l dialysate volume in selected patients

Merkel cell carcinoma (MCC) of the skin is a rare, primary malignant skin neoplasm which can present as a cutaneous nodule. These neoplasms are seen primarily in the elderly and located in the head and neck area or extremities. Twenty-nine aspirates from primary and metastatic lesions obtained by percutaneous fine-needle aspiration in 19 patients have been studied. The cytomorphologic features, clinical information, and immunocytochemical (ICC) findings are detailed. Aspirate smears demonstrated small-to-intermediate-sized cells with a loosely cohesive pattern. Nuclei were round with finely granular chromatin and multiple, small nucleoli. Cells possessed a thin rim of cytoplasm, and infrequent pseudorosette formations were noted in cell groups. ICC results were universally positive for cytokeratin, which showed a paranuclear "dot-like" pattern. Neuron-specific enolase, epithelial membrane antigen, and S-100 protein were positive in varying degrees. Leukocyte common antigen was universally negative. The diagnosis of MCC of the skin by FNA can be made by applying cytologic features in addition to ancillary studies and clinical information.     

A comparison of the temperature dependences of photoeffect quantum efficiencies in GaAs p-n structures and Schottky diodes

A comparison is made of how the quantum efficiencies for photoelectric conversion in p-n-and m-s-structures based on GaAs depend on temperature. For photon energies less than or the same order as the width of the band gap, the temperature dependences of the p-n-and m-s-structures are similar. In the range of photon energies larger than the width of the band gap, the quantum efficiency of p-n-structures is temperature independent, whereas the quantum efficiency of m-s-structures exhibits a strong temperature dependence. A qualitative explanation of this phenomenon is given. Fiz. Tekh. Poluprovodn. 33, 876–879 (July 1999)     

Epidermal growth factor (EGF) receptor blockade inhibits the action of EGF, insulin-like growth factor I, and a protein kinase A activator on the mitogen-activated protein kinase pathway in prostate cancer cell lines

For assays involving glycosyltransferases or transporters, several GDP-sugars are either commercially unavailable or expensive. We describe an enzymatic synthesis of GDP-d-[3H]arabinosep and GDP-l-[3H]fucose that yields 66-95% nucleotide-sugar from the appropriate radiolabeled sugar in less than 30 min. The coupled reaction requires Mg2+, ATP, and GTP along with the appropriate radioactive monosaccharide, sugar-1-kinase, and pyrophosphorylase. The latter two activities are present in a cytosolic fraction of Crithidia fasciculata, which is easily grown at room temperature in simple culture medium without serum or added CO2. Addition of commercial yeast inorganic pyrophosphatase shifts the equilibrium of the pyrophosphorylase reaction toward nucleotide-sugar formation. To verify that these nucleotide-sugars are biologically active, we tested their ability to serve as substrates for glycosyltransferases. GDP-l-[3H]fucose functions as the donor substrate for recombinant human fucosyltransferase V, and GDP-d-[3H]arabinosep serves as the donor substrate for the arabinosyltransferase activities present in Leishmania major microsomes.     

Structure and Superconducting Properties of Cd0.8Ba2(Y0.7Ca0.4)Cu3.5Oy

A new Cd-containing superconductor with nominal composition ofCd_0.8Ba₂(Y_0.7Ca_0.4)Cu_3.5O _y was synthesized and investigated. The obtained Cd and Ca-doped 123 phase exhibits an orthorhombic (T _c=80 K) or tetragonal (T _c=65 K) modification depending on the reaction atmosphere. It was shown that the combined Cd and Ca substitution facilitates the 123 phase formation. The results of the EDX analysis, as well as the comparison of the obtained lattice parameters with those of undoped, Cd-doped, and Ca-doped 123 have shown that both Cd and Ca enter the 123 phase and form a new Cd–Ba–Y–Ca–Cu–O superconducting compound.     

Synthesis and application of triazinyl-2,2,6,6-tetramethyl-piperidine derivatives as stabilizers for polymeric materials

Two new unsaturated compounds, i. e. triazinyl-2,2,6,6-tetramethylpiperidine derivatives (TTMP), were synthesized under conditions of phase-transfer catalysis and their copolymers with styrene (St) were prepared. The participation of TTMP in the polymerization did not affect the rate of copolymerization, molecular weight and polydispersity of the St polymers. At low concentrations (0.1 wt.-%) a significant stabilizing effect against photodegradation was determined.     

Macro- and Micromechanics of Pearlitic-Steel Deformation in Multistage Wire Production

Ninefold drawing of pearlitic steel wire is investigated. On the basis of multiscale computer models, the behavior of pearlite colonies at the surface of the wire and in its central layer is analyzed. The key factors are the orientation of the cementite lamellae relative to the drawing axis, the interlamellae distance, and the shape of the cementite inclusions. On the basis of finite-element models, the laws governing the reorientation of the pearlite colonies, change in shape and size of the cementite lamellae, and localization of the deformation in the ferrite are determined. The model results are verified by means of metallographic results and industrial experiments.     

In vivo and in vitro debromination of decabromodiphenyl ether (BDE 209) by juvenile rainbow trout and common carp

Decabromodiphenyl ether (BDE 209), the major congener in the high volume industrial flame retardant mixture "DecaBDE", has recently been shown to be metabolized by carp. To further explore this phenomenon, juvenile rainbow trout were exposed to BDE 209 via the diet for a five month period. Analysis of the whole body homogenate, liver, serum, and intestinal tissues revealed that BDE 209 accumulated in rainbow trout tissues and was most concentrated in the liver. In addition to BDE 209, several hepta-, octa-, and nonaBDE congeners also accumulated in rainbow trout tissues over the same period as a result of BDE 209 debromination. Based on the total body burden of the hepta- through decaBDE congeners, uptake of BDE 209 was estimated at 3.2%. Congener profiles were different among whole body homogenate, liver, and serum, with the whole body homogenates having a greater contribution of the debrominated biotransformation products. Extracts of the rainbow trout whole body homogenates were compared with extracts from a previous experiment with common carp. This comparison revealed that BDE 202 (2,2',3,3',5,5',6,6'-octabromodiphenyl ether) was a dominant debromination product in both studies. To determine whether the observed debromination was metabolically driven, liver microsomal fractions were prepared from both common carp and rainbow trout. Analysis of the microsomal fractions following incubation with BDE 209 revealed that rainbow trout biotransformed as much as 22% of the BDE 209 mass, primarily to octa- and nonaBDE congeners. In contrast, carp liver microsomes biotransformed up to 65% of the BDE 209 mass, primarily down to hexaBDE congeners. These microsomal incubations confirm a metabolic pathway for BDE 209 debromination.