Regulatory variants for the expression of H-2 antigens. I. Isolation and characterization

By subjecting "mutagenized" mouse myeloma cells repeatedly to selection with antiserum against H-2Kd, we isolated variants that expressed little or no H-2Kd alloantigens. The phenotype was unstable, with the culture accumulating revertants in the absence of selective pressure. The variants not only failed to express the selected antigen, but also the antigen coded by the closely liked H-2Dd gene. The cells reexpressed this antigen with the same kinetics as for the selected antigen. Several physiologic parameters (karyotype, cell morphology, size, and growth curves) were not altered by the loss of H-2 antigens.However,when injected iv, the H-2-deficient cells did not lodge in the spleen as readily as did the wild-type cells.     

Effect of Oxygen Doping on the IR Transmission and Cathodoluminescence of ZnSe

The effect of oxygen doping (0.9 and 4.3 vol % O₂in the gas phase) on the transmission and cathodoluminescence of CVD ZnSe was studied. The incorporation of oxygen was found to reduce the transmission in the spectral range 700–1900 cm^–1. Examination by scanning electron microscopy shows that Se excesses and high O₂concentrations lead to tabular growth. ZnO precipitation at structural defects during cooling was observed only in the end portion of the deposit. The dimensions of microinhomogeneities are shown to have a significant effect on the transmission of ZnSe. The oxygen-containing species present in the deposits were identified using cathodoluminescence spectra. The CL spectrum of Se-enriched p-type ZnSe is dominated by the band at 490 nm (SAL) at 80 K and the band at 640 nm (SA) at 300 K. The 640-nm band is attributed to recharging of the SALcenters upon a variation of the Fermi energy with temperature. Decreasing the Se excess leads to the quenching of the SALemission and appearance of the shorter wavelength component of the SAband at 600 nm (80–300 K), characteristic of slightly Zn-enriched ZnSe. The intensity of the self-activated bands is shown to increase as the concentration of dissolved oxygen increases.     

Fabrication and magnetic properties of submicro-textured magnetostrictive alloys

A novel method for fabrication of submicro-textured magnetostrictive alloys (Fe₈₅Ga₁₅) by using mechanochemical treatment of iron and gallium reactants followed high-temperature sintering is reported. To reduce the surface tension and enhance the chemical reaction between iron and gallium up to 1% of surfactant (oleic acid) was used during the mechanochemical synthesis of Fe₈₅Ga₁₅ particles. The sintered sample was processed using a flat-roll machine to obtain 100 μm thick ribbons at room temperature. The ribbons were annealed at 600 °C in argon and slowly cooled down for over 3 h. SEM analysis of the ribbons shows a submicron structure of the fabricated alloys. XRD data for annealed ribbons confirm a long-range ordering of Ga atoms into a DO₃ structure. The magnetization plot M (H) at 5 and 280 K of the Fe₈₅Ga₁₅ ribbon did not display a visible magnetic hysteresis loop and exhibited a very low coercivity of H _c = 4.7 and 1.9 Oe and remnant moment of M _rem = 0.28 and 0.1 emu/g, respectively, with a saturation magnetization of about 162 emu/g. A largest magnetostriction up to 220 ppm was measured along the ribbon length in a perpendicular magnetic field.     

The roles of muscarinic receptor subtypes in modulation of nasal ciliary action

OBJECTIVE: Clinicopathological features of mycobacteriosis were studied by means of microscopical examination of 34 autopsy cases in patients with acquired immunodeficiency syndrome (AIDS) and the diagnostic methods were evaluated. METHODS: All cases were anatomized, sampled, fixed and embedded routinely and stained with hematoxylin-eosin. Acid fast stain was applied to identify the mycobacteria. The pathological sections and files were reviewed systemically and retrospectively. RESULTS: Thirty-four cases of mycobacteriosis, including Mycobacterium avium-intracellular complex (MAI) infection (20 cases) and Mycobacterium tuberculosis (10 cases) and mixed infection of both pathogens (4 cases) were found out of 151 autopsy AIDS patients. MAI infection involved mostly the lymph nodes (21 cases) and followed by spleen, liver and lung, etc. The infection were often disseminated and characterized by proliferation of histocytes with foamy or vacuolar cytoplasm containing acid fast bacilli and formation of granulomatous nodules. Tuberculosis often involved the lung (10 cases) and lymph node (8 cases), the typical manifestations of which were caseous necrosis and tuberculation. Other opportunistic infections and neoplasmas occurred with mycobacteriosis in 25 cases. CONCLUSIONS: Mycobacteriosis, especially the tuberculosis and MAI infection are common in patients with AIDS, which are often disseminated and involved the lung and lymph node. The diagnosis can be made according to the specific pathological appearances and positive acid fast stain.     

Mathematical Model of Foraging in a Group of Robots: Effect of Interference

In multi-robot applications, such as foraging or collection tasks, interference, which results from competition for space between spatially extended robots, can significantly affect the performance of the group. We present a mathematical model of foraging in a homogeneous multi-robot system, with the goal of understanding quantitatively the effects of interference. We examine two foraging scenarios: a simplified collection task where the robots only collect objects, and a foraging task, where they find objects and deliver them to some pre-specified home location. In the first case we find that the overall group performance improves as the system size grows; however, interference causes this improvement to be sublinear, and as a result, each robot's individual performance decreases as the group size increases. We also examine the full foraging task where robots collect objects and deliver them home. We find an optimal group size that maximizes group performance. For larger group sizes, the group performance declines. However, again due to the effects of interference, the individual robot's performance is a monotonically decreasing function of the group size. We validate both models by comparing their predictions to results of sensor-based simulations in a multi-robot system and find good agreement between theory and simulations data.     

Various aspects of price formation in public health

The main problems involved in estimating the cost of medical service are discussed. Up to the present time, there was no universal approaches to price formation in practical public health. Economists and public health organizers are not trained to cope with this task. Based on the results of five-year studies and published data, the author present in detail the methodology of practical price formation and offer the typical problems in price estimation. The recommendations contained in this paper will help improve the work of specialists in price formation and aid all those engaged in the sphere of paid medical service.     

The localization and functional significance of arylsulfatases in parasitic sarcosporidian protozoa in the tissue-cyst life cycle phase

Ten patients with perennial allergic rhinitis and 10 healthy subjects were studied to determine most discriminative nasal irrigation fluid marker(s) and to compare samples that were collected at baseline and over a 1-hour period, every 15 minutes. The latter were pooled and designated 1-hour sample. In the nasal irrigation we investigated the following inflammatory cells and soluble mediators: eosinophils, neutrophils, granulocyte-macrophage colony-stimulating factor, interleukin-4, interleukin-6, interleukin-8, ECP, EPX, MPO, leukotriene C4, leukotriene B4, prostaglandin E2, tryptase and fibrinogen. Patients with PAR were then treated for 2 weeks with the topical nasal steroid. The only marker that discriminated patients with perennial allergic rhinitis and healthy subjects was eosinophil count (EO%): correspondingly 14.01 +/- 5.8 and 0.18 +/- 0.09, (M +/- SD). Difference between the studied groups did not depend on the time of irrigation, baseline or 1-hour. EO% was also the only marker of a clinically successful treatment with the nasal steroid, 14.01 +/- 5.8 and 0.87 +/- 0.4, before and after treatment respectively. We conclude that EO% is the most sensitive inflammatory marker of perennial allergic rhinitis, and that baseline nasal irrigation can be used to study nasal mucosal inflammation.     

SEM-CL studies of plastic deformation processes in crystals

Cathode luminescence investigation in the scanning electron microscope showed that, under a concentrated load, enormous stresses (near G) under the indenter relaxed due to the creation and movement of interstitials giving rise to structure reconstruction and the formation of an ultradispersed state. Such reconstruction is accompanied by significant changes in material stoichiomentry. The formation of a volume with nanocrystal structure affects microindentation activation energy. The formation and displacement of dislocations around the impression should be considered as a process secondary to stress relaxation, that is, as a result of the reorganization of material structure under the indenter tip described.