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The effects of thermal annealing on electrical and structural characteristics of iridium (Ir) Schottky contacts to n‐type InGaN have been studied using current–voltage (I–V), capacitance–voltage (C–V), secondary ion mass spectrometer (SIMS), and X‐ray diffraction (XRD) measurements. Measurements showed that the Schottky barrier height (SBH) of as‐deposited sample is 0.79 eV (I–V) and 1.07 eV (C–V). It is observed that the barrier height increases to 0.85 eV (I–V) and 1.21 eV (C–V) after annealing at 300 °C for 1 min in N2ambient. However, it is found that the SBH slightly decreases when the contacts are annealed at 400 and 500 °C and the corresponding values are 0.84 eV (I–V), 1.17 eV (C–V) for 400 °C and 0.80 eV (I–V), 1.11 eV (C–V) for 500 °C, respectively. Using Cheung's functions, the barrier height (Φb), ideality factor (n), and series resistance (Rs) are also calculated. From the above results, it is clear that the optimum annealing temperature for Ir Schottky contact is 300 °C. SIMS and XRD results shows that the formation of gallide phases at Ir/n‐InGaN interfaces could be the reason for variation in the SBHs upon annealing at elevated temperatures. Atomic force microscopy (AFM) results show that the overall surface morphology of Ir Schottky contacts on n‐InGaN stays reasonably smooth. These results make Ir Schottky contacts attractive for high‐temperature device applications.

Among several bacteria examined in this study, a hyper acidophil and thermostable Micrococcussp.NS 211 designated as M.Amy NS 211 was selected for production of amylase using starch agar plates with following incubation at 85°C. Identification by 16SrRNA on selected bacterium disclosed the highest similarity for protean regions of this gene, 27 F and 1492R as Micrococcussp.NS 211. Although activity of M.Amy NS 211 was established at temperatures between 70 and 110°C and pH ranges 1.2–8.0, the optimum temperature and pH was achieved at 85°C and 3.5 in sodium citrate buffer system respectively. Two‐step chromatography was performed using (CM Bio‐Gel A) and (Bio‐Gel A‐150) columns to purify 84 kDa hyper acidophil and thermostable α‐amylase. SDS‐PAGE analysis showed molecular mass and amylolytic activity as single band. Enhancement of enzyme activity was obtained in presence of 5 mM MnCl2(298%), CaCl2(347%), FeCl2(211%), MgCl2(253%), ZnCl2(146%), NiCl (142%), NaCl (141%), Na‐sulfate (153%) while inhibition was observed with (5 mM) EDTA, PMSF (3 mM), urea (8 M), and SDS (1%) at 143, 134, 43, and 119%, respectively. M.Amy NS 211 can be applied in laundry detergents, textile, and modern relevant industrial processes at extreme temperatures and under acidic conditions.

Mechanisms regulating coronary vascularization are not well understood. To test hypotheses regarding the influence of key growth factors and their interactions, we studied vascular tube formation (vasculogenesis) in collagen gels onto which quail embryonic ventricles were placed and incubated in the presence of growth factors or inhibitors. Vasculogenesis in this model is dependent on tyrosine kinase receptors, since tube formation was totally blocked by genestein. Tube formation was attenuated when anti-bFGF or anti-VEGF neutralizing antibodies were added to the medium and nearly completely inhibited when the both were added. The attenuation associated with anti-VEGF was due primarily to a decrease in assembly of endothelial cells, while that associated with bFGF was primarily due to a reduction in endothelial cells. Soluble tie-2, the receptor for angiopoietins, also had an inhibitory effect and, when added with either anti-bFGF or anti-VEGF, markedly attenuated tube formation. At optimal doses, tube formation was enhanced 6.5-fold by bFGF and 2.5-fold by VEGF over the controls. Each of these growth factors was dependent upon the other for optimal induction of tube formation, since neutralizing antibodies to one markedly reduced the potency of the other. VEGF potency was also markedly reduced when soluble tie-2 was added to the medium. Tube formation was virtually totally blocked by exogenous TGF-β at doses > 1 ng/ml, while neutralizing TGF-β antibodies enhanced tube formation 2-fold in the 30 ng–30 μg range. These data provide the first documentation of multiple growth factor regulation of coronary tube formation. © 2001 Wiley-Liss, Inc.

A theoretical model is proposed to investigate the coupled effects of thermal radiation and electromagnetic field on the blood flow in a stenosed tapered artery. Here, blood is treated as a non-Newtonian Jeffrey fluid model which includes magnetic particles. The magneto-hydrodynamic flow is pulsatile, and exhibits slip velocity at the complaint wall. The flow medium consists of a cylindrical rigid tube with porous medium that is subjected to periodic body acceleration, transverse external magnetic field and applied electric field in the axial direction. Assuming the existence of mild stenosis, a set of flow governing equations is solved using integral transform method. Further, exact solutions are computed for non-dimensional temperature and velocity profiles of fluid and particles. Additionally, equations for different flow characteristics such as wall shear stress, volumetric flow rate, and flow resistance are derived and discussed through graphical illustrations. Results demonstrate that the temperature of blood increases with the increase of heat absorption coefficient and time. However, the temperature decreases with the increase of radiation number and Peclet number. While the velocity profile is directly proportional to the Grashof number and heat absorption coefficient, it is inversely proportional to the radiation number and Peclet number. The applied electric field diminishes the magnitude of fluid’s flow resistance, but it increases with the increase of the magnetic field strength. By combining heat radiation with electromagnetic field, this study contributes to new insights to the physical properties of blood.

In view of the evidence that thyroid hormone administration has angiogenic effects on the hypertrophic myocardium, we tested the hypothesis that the capillary supply in the hypertrophic myocardium surviving infarction would be improved by administration of the thyroid hormone analog, diiodothyroproprionic acid (DITPA). We administered DITPA (MI-DITPA) or saline (MI-saline), s.c., to rats for 10 days following experimental infarction of the left ventricle (LV). Morphometric methods were used to assess capillarity and myocyte cross-sectional area in three regions of the left ventricle: (1) border (next to the scar of infarction); (2) adjacent (next to the border); and (3) remote (interventricular septum). Infarct size ranged from 20–85% of the LV free-wall, and both groups had similar mean infarct size. Capillary length density (Lv) was significantly higher in the remote region of the treated group than in the MI-saline rats. Lvin the border region, which experienced the most marked increase in cardiocyte cross-sectional area, was not significantly lower than in the other regions, indicating a more marked angiogenic response. In hearts with large infarcts (≥40%) Lvin the border region was higher in the DITPA group than in the non-treated rats. In the MI-DITPA group, cardiocyte size in the border region was positively correlated with that of the other regions, which contrasts with the negative correlations noted for the MI-saline rats. These data suggest that DITPA therapy (1) may improve maximal perfusion potential of the hypertrophied myocardium surviving a myocardial infarction, and (2) is selectively effective in the border region of hearts with large infarcts.

TheV-I characteristics of thermally grown titanium oxide films on titanium are described and are explained using a model for current transport in the films.

This paper describes a theoretical model for the growth of titanium oxide by thermal oxidation of titanium. It is shown that this model can explain the formation of layers of different oxides of titanium and the changes in these layers with variations in the conditions of oxidation. Some experimental X-ray diffraction results which support the model are also given.

Letf(x)∈Q[X] be a cubic such thaty2=f(x) is an elliptic curve with complex multiplication by[formula],[formula],[formula]or[formula]. We want to calculate the character sum[formula]where (·/p) is the Legendre symbol. We show that it is enough to calculate the sum for a finite number of primes and this has been done.

A new scale of electronegativity based on X-ray spectroscopic data was earlier presented by Mande and others for the elements3Li to54Xe. The present paper reports an extension of this scale carried out for most of the heavier elements lying between55Cs and92U. The present approach is based on the physical interpretation of electronegativity of an atom as the attractive electrostatic force it exerts at a distance equal to its covalent radius. To estimate this force, experimental spectroscopic data have been employed. The merits of such an approach have been pointed out recently by Mullay and may be of interest in the context of the intimate relation found between electronegativity and superconducting transition temperature.

SEVERAL claims have been made about the successful separation of Y-bearing spermatozoa in the past1. The most recent claim by Ericsson et al.2has been disputed3,4. We have attempted to develop a method for separating human X- and Y-bearing spermatozoa, without affecting the motility or the variability of these vital cells. We report here a successful separation of human X- and Y-bearing spermatozoa using a two-step procedure with Ficoll–Sodium metrizoate density gradient. The motility and viability of enriched fractions of spermatozoa was found to be slightly reduced. The reduction was mainly due to centrifugation and not the density gradient. The ability to predetermine the sex of the offspring before conception would have great clinical and sociological significance5.

Summary.Dithiothreitol was used to decondense the nuclear chromatin before staining human spermatozoa with quinacrine for the F body present in Y-bearing spermatozoa. In unseparated fractions and those enriched in X- or Y-bearing spermatozoa, the number of spermatozoa with F bodies increased by 2–9% after dithiothreitol treatment.

Healthy and mosaic infected leaves ofL. nudicaulishave been cultivated onMSand modifiedMSmedia (MC). Profuse growth and differentiation of tissue have been obtained onMSmedium in diseased tissues as compared to the modified medium. It has been found on bioassay that although there is no difference between the concentration of the virus in tissue culture and glasshouse material yet the incubation period of the virus is decreased in tissue cultures. Zdravé a infikované listyLaunaea nudicaulisbyly kultivovány na mediu podleMurashigeaSkoog-a bez (MS) a ś příměsí 15% kokosového mléka a 4 ppm 2,4-D (MC). Mohutnějšího růstu a diferenciace infikovaných pletiv bylo dosaženo na mediuMSve srovnání sMC. Biologickým testem bylo zjištěno, že inkubační doba viru se v tkáňové kultuře zkracuje, ačkoli koncentrace viru v tkáňové kultuře a ve skleníkovém materiálu byla stejná.

Poly (ethylene oxide) (PEO) based gel polymer electrolytes (GPEs) with added acetamide, NaI/I2 have been prepared for dye-sensitized solar cells application (DSSC). The Dye-sensitized solar cell investigated the performance of the optimized gel polymer electrolyte. GPEs synthesized by adding up of acetamide with different wt% in poly (ethylene oxide) (PEO) and poly (ethylene glycol) dimethyl ether (PEGDME) with NaI/I2. A maximum power conversion efficiency of 5.92% is achieved for PEO/PEGDME with 10 wt% acetamide in the photovoltaic performance under 100 mW/cm2 illumination and it exhibits maximum ionic conductivity (s = 2.81x10-3 S/cm) among all electrolytes, compared to PEO without acetamide (e = 4.35%). The gain in open circuit voltage (Voc) was observed for GPEs due to the decrease in the recombination effect and electron lifetime increases by the addition of acetamide on the PEO. The fill factor (FF) is increased due to the growth in the ionic conductivity and amorphous nature of the GPE increases by the addition of acetamide on the PEO.

An increase in the number of amino acids inAmaranthus viridisplants infected with pigweed mosaic virus was found.

Microbial growth and antimicrobial bacterial killing are both diminished in abscesses. It was postulated that zinc depletion in abscesses, perhaps secondary to a neutrophil protein resembling calprotectin, may be partly responsible for these effects. In a rabbit tissue-cage abscess model, pooled abscess supernatant concentration of zinc was <1.531µM. The addition of 41.7 µM zinc had no effect on Staphylococcus aureus growth or the bacterial killing effect ofcefazolin in serum. In abscess fluid supernatants, bacterial growth without antibiotic and bacterial killing by cefazolin were both enhanced by the addition of zinc. Fractionation of the abscess fluid with ultrafiltration membranes showed that these effects could be reproduced with the fraction between 30 and 50 kDa. These findings suggest that a protein in abscess fluid supernatants that resembles the neutrophil protein calprotectin may, through its zinc binding effects, inhibit microbial growth within an abscess but also inhibit the activity of bactericidal antibiotics.