Optical emission spectroscopic study for diagnostics in high gravity DC-plasma CVD diamond growth

The effect of gravity on materials processing is rather complicated, and a large number of considerably unexpected results due to high gravity or sometimes centrifugation have been reported. The authors have been conducting high gravity diamond thin film growth by the DC-plasma CVD method up to 100 G. The effects of high gravity appeared in the nucleation site density, growth rate, grain size, uniformity, film coverage and morphology. With the increase in gravity, the nucleation site density, growth rate, grain size were all found to be increased, the uniformity and film coverage were improved, and {100} facet became dominant rather than {111} facet. To understand the deposition mechanism in these effects observed in high gravity, a diagnostic apparatus for spectroscopic study of the optical emission from the DC-plasma was developed, and the OES (optical emission spectroscopy) apparatus has been employed in high gravity CVD experiments. The influence of gravity on the most active species in the plasma, such as H, CH, C₂ was discussed together with the results from the Raman spectroscopy and X-ray diffraction study.     

CuPc/PbZr0.2Ti0.8O3/(La,Ba)MnO3 field effect transistor heterojunction photomemory

We investigated a photoconductor(PC)/ferroelectric oxide(OF)/semiconductor oxide(SO) POS-FET structure photomemory consisting of organic photoconductor CuPc/inorganic ferroelectric PbZr_0.2Ti_0.8O₃ heterojunction gate and a ferromagnetic oxide semiconductor La_0.87Ba_0.13MnO₃ channel. Visible light information detected by photoconductor CuPc can be memorized in ferroelectric PbZr_0.2Ti_0.8O₃, and non-volatile and non-destructive reading out process of light information memorized in this ferroelectric layer were achieved by reading out the resistance modulation of ferromagnetic semiconductor oxide La_0.87Ba_0.13MnO₃ channel under the photoconductor/ferroelectric gate.     

Mitotic chromatin regulates phosphorylation of Stathmin/Op18

Meiotic and mitotic spindles are required for the even segregation of duplicated chromosomes to the two daughter cells. The mechanism of spindle assembly is not fully understood, but two have been proposed that are not mutually exclusive. The 'search and capture' model suggests that dynamic microtubules become progressively captured and stabilized by the kinetochores on chromosomes, leading to spindle assembly. The 'local stabilization' model proposes that chromosomes change the state of the cytoplasm around them, making it more favourable to microtubule polymerization. It has been shown that Stathmin/Op18 inhibits microtubule polymerization in vitro by interaction with tubulin, and that overexpression in tissue culture cells of non-phosphorylatable mutants of Stathmin/Op18 prevents the assembly of mitotic spindles. We have used Xenopus egg extracts and magnetic chromatin beads to show that mitotic chromatin induces phosphorylation of Stathmin/Op18. We have also shown that Stathmin/Op18 is one of the factors regulated by mitotic chromatin that governs preferential microtubule growth around chromosomes during spindle assembly.     

Sequence analysis of functional regions of homoserine dehydrogenase genes from L-lysine and L-threonine-producing mutants of Brevibacterium lactofermentum

The homoserine dehydrogenase (HD) genes from Brevibacterium lactofermentum lysine- and threonine-producing mutants were cloned, using the polymerase chain reaction, and sequenced. We found the amino acid substitutions, Val104Ile in the lysine-producing mutants in which HD may cause leaky mutation and Ser393Phe in the threonine-producing mutant with feedback-insensitive HD.     

Theory and clinical application of functional MRI: 3D-functional brain mapping

Functional magnetic resonance imaging (fMRI) was performed using a clinical 1.5 T MR scanner. Normal volunteers and patients with several neurological disorders were studied with somatosensory stimulation using sponge at right hand and visual stimulation using checkerboard pattern. Both fMR images by gradient echo echo planar imaging and three dimensional gradient echo images were studied. Reconstructed 3 dimensional functional brain mapping was superimposed on 3D anatomical images. Apparent signal increase was observed at contra lateral sensorimotor cortex and secondary sensory cortex with sponge stimulation. In the case of left homonymous hemianopia due to cerebral infarction, increasing signal was only observed surrounding left calcarine fissure by using stimulation of all visual field. In conclusion, fMRI and 3-D functional brain mapping has extremely high potentiality to examine pathophysiology of various neurological disorders.     

A minimal role for selectins in the recruitment of leukocytes into the inflamed liver microvasculature

A two-step paradigm for leukocyte recruitment has been established in a number of tissues including the mesentery, skin, and muscle, and necessitates an initial rolling step via the selectins before firm leukocyte adhesion via the integrins. In view of the many inflammatory diseases that involve the liver, we investigated the importance of rolling and the selectins in the hepatic microvasculature and compared the responses to that of the commonly used mesentery or cremaster microvasculature. We visualized the liver microvasculature using intravital microscopy and we determined that within the liver the majority of leukocytes adhere within the sinusoids (80%) in response to a chemotactic stimulus such as FMLP (20% in postsinusoidal venules) whereas leukocytes adhere exclusively within postcapillary venules in tissue like the mouse cremaster. In the sinusoids, the adhesive response to FMLP is not dependent upon selectins inasmuch as adhesion was not reduced in the sinusoidal vessels of P-selectin-deficient mice or E-selectin/P-selectin- deficient animals in the presence or absence of L-selectin antibody. No rolling or adhesion was detected in response to FMLP in the selectin-deficient cremaster microvasculature. Immunoneutralization of selectins with fucoidan in wildtype mice eliminated rolling and adhesion in the cremaster but failed to affect adhesion in the liver sinusoids in response to FMLP. More long-term leukocyte recruitment with lipopolysaccharide (4 h) was also impaired in the cremaster but not the liver microvasculature in selectin-deficient animals. Leukocyte adhesion in the sinusoids was reduced in P-selectin-deficient mice also lacking intercellular adhesion molecule-1 (ICAM-1). This study for the first time demonstrates that selectins are not an essential step for leukocyte recruitment into the inflamed liver microvasculature.     

Mseleni and Handigodu familial osteoarthropathies: syndromic identity?

New procedures of laser therapy and chemotherapy have extended the scope of application of organ-saving treatment at advanced stages of retinoblastoma in childhood, thus making it possible to preserve the eye fully functional or cosmetic. Not having to perform such mutilating procedures as ophthalmectomy or eye socket exenteration contributes to psychological and physical rehabilitation. At the same time, as a comparison of the results of surgery carried out at initial stages and surgery-free treatment showed that palliative therapy is characterized by impressive rates of 5-year survival. New vistas have opened of in the management of pediatric retinoblastoma, particularly in cases of stage III tumor and bilateral involvement.     

Ca2+ release induced by rapid cooling and caffeine in ferret ventricular muscles

The cytotoxic effects of a novel compound, conjugate Se-Pt [(NH3)2Pt (SeO3)] on blood platelet function (aggregation, release of adenine nucleotides) were studied. Contrary to the action of cisplatin or selenite alone, [(NH3)2Pt(SeO3)] did not inhibit ADP-induced platelet aggregation, thrombin-induced release of adenine nucleotides from platelets, and had no effect on the metabolism of platelet arachidonate. The tested compound seems to be less toxic than cisplatin alone, and has no effect on blood platelet activation.     

Cultured postnatal rat septohippocampal neurons change intracellular calcium in response to ethanol and nerve growth factor

Ethanol exposure affects cellular mechanisms involved in the regulation of calcium (Ca2+) homeostasis. Neurotrophins, such as nerve growth factor (NGF), stabilize intracellular Ca2+([Ca2+]i) during a variety of neurotoxic insults. In this study, changes in [Ca2+]i during treatment with ethanol and NGF were measured at the cell body of neurons using the Ca2+ indicator indo-1. Cultured postnatal day-of-birth (P0) septohippocampal (SH) neurons that were labeled with 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanine perchlorate (DiI), increased [Ca2+]i in response to ethanol. This response was dose-related. P0 SH neurons treated with NGF had lower [Ca2+]i than neurons withdrawn from NGF, implying that NGF may modulate Ca2+ homeostasis in these neurons. NGF also prevented the dose-related increase in [Ca2+]i in ethanol-treated SH neurons. The SH neurons increased [Ca2+]i when they were stimulated with 30 mM potassium chloride (KCl). Ethanol inhibited the potassium-stimulated change in [Ca2+]i but the combination of ethanol and NGF caused [Ca2+]i to increase with 100 mg% and 400 mg% ethanol and to decrease to a lower level with 200 mg% ethanol. These data were compared to data from previously published similar aged medial septal (MS) neurons (B. Webb, S.S. Suarez, M.B. Heaton, D.W. Walker, Clin. Exp. Res. 20 (1996) 1385-1394) and with embryonic gestational day 21 (E21) SH neurons (B. Webb, S.S. Suarez, M.B. Heaton, D.W. Walker, Brain Res. 729 (1996) 176-189). Differences in [Ca2+]i responses were observed in ethanol and NGF-treated postnatal SH neurons compared with P0 MS neurons and E21 SH neurons. Of these differences, most occurred during the combined treatment with ethanol and NGF compared with either treatment alone.