The biotype and genetic characteristics of an isolate of the cowpox virus causing infection in a child

The study included 138 patients operated on for endo-extracellular pituitary adenomas which extend both intracranially and into the structures of the base of the skull. Operations via transcranial and transsphenoidal access to various tumor sites were performed in 38 patients (a main group), while 100 patients (a control group) underwent one of these operations. Two-stage operations, followed by removal of the suprasellar and basal regions of a tumor, are expedient for enhancing the efficiency of surgical treatment, reducing the incidence of complications associated with traumatic attempts at removing tumor parts hard-to-reach by transcranial or transsphenoidal approaches, as well as at reducing the number of relapses. At the first stage of surgical treatment it is advisable to make an intervention via transcranial access especially in cases of complex configuration of the suprasellar part of a tumor. The recommended interval between transcranial and transsphenoidal surgeries is 3-5 months. Two-stage surgical treatment does not lead to significant structural changes and to the increased number of complications, and to higher mortality rates as compared to one-stage surgery (transcranial or transsphenoidal surgeries alone).     

Metabolism, intensity of lipid peroxidation and the antioxidant defense system in humans during chamber experiments with long-term isolation

Blood biochemical parameters of lipid, protein, carbohydrate and energy metabolism were measured in a 135-day chamber experiment. Also, dynamics of the intensity of lipid peroxidation and status of the antioxidant defence system were evaluated. Results of the investigation showed that extended chamber isolation led to modifications of several biochemical parameters including hemoglobin, bilirubin, cholesterol and its fractions, elevated transaminase activity which are typical for long-term space mission. However, these were not accompanied by substantive changes in protein, energy and carbohydrate metabolisms, or intensity of free radical processes. Effects of prolonged stay in chamber was successfully counterbalanced by organism.     

Defects in a-Si:H films induced by Si ion implantation

Undoped a-Si:H films implanted with silicon ions (dose 10¹²–10¹⁴ cm⁻², mean energy ɛ=60 keV) at room temperature have been studied. The following results of the interaction of such films with ion beams have been established: formation of defects (dangling Si-Si bonds) in the neutral state (D ⁰), change in the charge state D ⁰→D ⁻, the a-Si:H→a-Si transition, and growth of inhomogeneity of the structure. It is shown that these effects depend on the initial structures and electronic characteristics of the films. Fiz. Tekh. Poluprovodn. 33, 464–468 (April 1999)     

Fabrication of a plane-parallel interface in Ni/PbZr<Subscript>0.2</Subscript>Ti<Subscript>0.8</Subscript>O<Subscript>3</Subscript> heterostructures

A process has been proposed for producing a plane-parallel ferromagnetic/ferroelectric interface, which ensures a reproducible magnetoelectric performance of Ni/PbZr_0.2Ti_0.8O₃ (PZT) heterostructures. Its principle is to smooth the initial surface profile of the PZT ceramic substrate to a submicron level by sequential deposition/sputtering of three layers 0.2, 0.1, and 0.05 μm in thickness through ion beam sputtering of a target having the same composition as the substrate, followed by the growth of a nickel film on the smoothed surface. This allows one to preclude film bulging and spalling and ensures high quality of the interface.     

Separately bounded InGaAsP high-power laser heterostructures obtained by VPE of organometallic compounds

InGaAsP/InP laser heterostructures with two stressed quantum wells operating in the wavelength range 1.3–1.55 μm were obtained by VPE of organometallic compounds. An optical emission power of 2.4 W was reached for the laser diodes with 100-μm wide strips operated in the continuous lasing mode at 20°C. A minimum threshold current density was 260 A/cm². A differential quantum efficiency η_d= 40% was obtained with a 1.9-mm-long Fabry-Perot resonator. The internal optical losses of the heterostructures are reduced to 2.6–4.2 cm⁻¹.     

Properties of wide-mesastripe InGaAsP/InP lasers

Wide-mesastripe InGaAsP/InP heterostructure lasers emitting at 1.3–1.5 µm were grown by metal-organic chemical vapor deposition (MOCVD). Radiation-power-current and spectral characteristics of the lasers have been studied in pulsed and continuous wave (cw) operation in the temperature range of 10–60°C. The temperature of the active region of the diode laser is higher by 30–60°C than that of the copper heatsink upon saturation of the cw output power. The temperature dependence of the differential quantum efficiency strongly affects the cw output power. Output powers of 3 and 2.6 W are achieved in mesastripe lasers in cw operation, and 9 and 6.5 W in pulsed operation, at wavelengths of 1.3 and 1.5 µm, respectively.     

Self-organization processes in the organic-inorganic disperse system containing silver nanoparticles

The morphology of complexly organized structures formed in polymer matrix under the action of silver nanoparticles has been investigated using atomic-force microscopy. The analysis of the set of experimental data and the results of the theoretical calculations of the pair interaction potentials has made it possible to propose the mechanism of formation of the “flower” structure, which is based on the interactions in the far potential minimum.     

Short-range and long-range aggregation of particles in the γ-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> sol: II. Photometric and ultramicroscopic investigation of the aggregate stability of the positively charged γ-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> sol

The aggregate stability of the positively charged γ-Al₂O₃ (alundum) sol has been investigated using photometry and flow ultramicroscopy over a wide range of KCl concentrations. The data on the sol stability have been compared with the results of the calculations in the framework of the extended Derjaguin-Landau-Verwey-Overbeek theory. The parameters of the long-range structural forces for γ-Al₂O₃ particles have been evaluated. The role of the far potential minimum in the sol stability has been discussed.