2,240 research outputs found
FUNCTION OF NAD GLYCOHYDROLASE IN ADP-RIBOSE UPTAKE FROM NAD BY HUMAN ERYTHROCYTES
No full textThe function of the ectoenzyme NAD glycohydrolase (NADase) in ADP-ribose uptake from extracellular NAD was studied in human erythrocytes that express relatively high NADase activity (adult erythrocytes) and erythrocytes expressing very low activity (newborn erythrocytes). The rates of ADP-ribose uptake from NAD in human erythrocytes were correlated with their NADase activities. In contrast, there was no significant difference in the rates of ADP-ribose uptake among these cells when incubated with ADP-ribose. These results indicate that ecto-NADase may have a role as supplier of ADP-ribose for its uptake into the cells and that the cleavage of NAD by NADase is necessary for the ADP-ribose uptake by human erythrocytes. From ADP-ribose uptake studies at 37-degrees-C a K(m) of 0.7 +/- 0.05 muM and a V(max) of 2.04 +/- 0.1 pmol/min per mul cell water was found for the uptake of [H-3]ADP-ribose. The thiol-reactive reagents p-chloromercuribenzene sulfonic acid and N-ethylmaleimide inhibited the uptake ADP-ribose with IC50 values of 50 +/- 4 and 750 +/- 25 mM, respectively. Since efflux of [H-3]ADP-ribose was negligible, the ADP-ribose transport system appears to be unidirectional. The unidirectionality was supported by the evidence that transported ADP-ribose was rapidly degraded to AMP which is impermeable to the membrane.
Preparation of a-SiNx thin film with low hydrogen content by inductively coupled plasma enhanced chemical vapor deposition
No full textAmorphous silicon nitride (a-SiNx) thin films are deposited at low temperature by remote-type inductively coupled plasma enhanced chemical vapor deposition (ICP-CVD) using N-2/SiH4 gases as reactant gases to obtain low hydrogen content in the films. Refractive index, deposition rate, stoichiometry, hydrogen content, and hydrogen configuration in the films are analyzed with the varation of deposition parameters. As RF power and N-2 flow rate increase, refractive index decreases due to the decrease of Si/N ratio, total hydrogen content is constant with N-H changing hydrogen bond configurations (Si-H, N-H) reversely. However, as substrate temperature increases, refractive index increases due to the reduction of Si/N ratio, and total hydrogen content as well as both hydrogen bond configurations (Si-PI, N-H) decrease. In remote-type ICP-CVD using N-2/SiH4 gases, N rich a-SiNx films with low refractive index and density are deposited due to efficient dissociation of N-2 gas by high density plasma, and hydrogen content in the films is greatly reduced.This work was supported by Ministry of Education through Interuniversity Semiconductor Research Center(ISRC 96-E-4021)in Seoul National University.
Korea Advanced Institute of Science and Technology assisted in meeting the publication costs of this article
Formation identification of Y2BaCuO5 and BaCeO3 in MOCVD-processed YBCO films with Ce doping
No full textThe influence of nanosized secondary particles, such as those produced via rare-earth doping for example, on magnetic-field-induced flux motion in YBa2Cu3O7-delta (YBCO)-coated conductors has been investigated. In this study, we investigated the influence of Ce doping on nanosized secondary phase formation in YBCO films. Ce-doped YBCO films on single SrTiO3 crystals were prepared viametal-organic chemical vapor deposition (MOCVD). For the first time, a Y2BaCuO5 (Y211) secondary phase was observed in the Ce-doped YBCO film, while the pure YBCO film contained only a Y2O3 secondary phase. As Ce doping concentration increased to 3 wt%, a BaCeO3 secondary phase developed. This was due to the low solubility limit of Ce for Y in the MOCVD YBCO film. Additionally, outgrowths on the Ce-doped YBCO film surfaces and defect structures, such as a-axis grains, were examined
Interpolating sequences for H∞(BH)
No full textWe prove that under the extended Carleson’s condition, a sequence (xn) ⊂ BH is linear interpolating for H∞(BH) for an infinite dimensional Hilbert space H. In particular, we construct the interpolating functions for each sequence and find a bound for the constant of interpolation.The author is supported by Project MTM 2011-22457 (Ministerio de Economía y Competitividad, Spain) and Project P1-1B2014-35 (Universitat Jaume I, Spain
NOVEL TRANSFORMER ACTIVE-FILTERS
No full textNovel transformer active filters are proposed to obtain high attenuation of voltage or current ripple without deteriorating transient response of the considered system. Experimental results show that the proposed scheme gives good steady-state performance of the power supply.X114sciescopu
Caregiver-administered neuropsychiatric inventory (CGA-NPI)
No full textThe Neuropsychiatric Inventory (NPI) is used to assess neuropsychiatric symptoms in dementia patients. To reduce clinicians' time taken to administer the NPI, the authors studied a caregiver-administered NPI (CGA-NPI), in which caregivers completed the written form of the NPI worksheet. After a brief presupervision session, the caregivers of 61 dementia patients completed the CGA-NPI by reading through the worksheet. This was followed by a postsupervision session to check if the caregivers had completed the form appropriately. The correlation between the prevalence rates of each neuropsychiatric symptom obtained by the CGA-NPI and those obtained by the NPI was fair to good (kappa = 0.57-0.90) in all domains. All frequency, severity, and caregivers' distress scores of the CGA-NPI correlated significantly with those of the NPI (r > 0.6, P < .001). Total CGA-NPI scores also correlated highly with total NPI scores (r = 0.86, P < .001). These results suggest that the CGA-NPI can substitute for the NPI, saving administration time
Analysis of poly(3-hydroxybutyrate) granule-associated proteome in recombinant Escherichia coli
No full textPoly(3-hydroxybutyrate) [P(3HB)] is a microbial polyester intracellularly accumulated as distinct granules ill numerous microorganisms as an energy and carbon storage material. Recombinant Escherichia coli harboring the heterologous P(3HB) biosynthesis genes accumulates large amounts of P(3HB) granules, yet the granule-associated proteins have not been identified. Therefore, this study reports oil an analysis of the P(3HB) granule-associated proteome in recombinant E. coli. Five proteins out of 7 spots identified were found to be involved in functions of translation, heat-stress responses, and P(3HB) biosynthesis. Two of the major granule-associated proteins, IbpA/B, which are already known to bind to recombinant proteins forming inclusion bodies in E. coli, were further analyzed. Immunoblotting and immunoelectron microscopic studies with IbpA/B antibodies clearly demonstrated the binding and localization of lbpA/B to P(3HB) granules. IbpA/B seemed to play an important role in recombinant E. coli producing P(3HB) by stabilizing the interface between the hydrophobic P(3HB) granules and the hydrophilic cytoplasm. Thus, IbpA/B were found to act like phasins in recombinant E. coli, as they are the major proteins bound to the P(3HB) granules, affect the morphology of the granules, and reduce the amount of cytosolic proteins bound to the P(3HB) granules.The authors would like to thank E. Laskowska (Gdansk,
Poland) for the anti-IbpA/B sera. This work was supported by
a Korean Systems Biology Research Grant (M10309020000-
03B5002-00000) from the Ministry of Science and
Technology. Further support from the CUPS, LG Chem
Chair Professorship, IBM SUR program, Microsoft, and
Brain Korea 21 project is appreciated
Significance of ecto-cyclase activity of CD38 in insulin secretion of mouse pancreatic islet cells
No full textCyclic ADP-ribose (cADPR), a product of CD38, has a second messenger role for in intracellular Ca2+ mobilization from microsomes of pancreatic islets as well as from a variety of other cells. ADP-ribosylation of CD38 by ecto-mono ADP-ribosyltransferase in activated T cells results in apoptosis as well as inactivation of its activities. We, therefore, examined the effect of ADP-ribosylation of CD38 in mouse pancreatic islet cells. NAD-dependent inactivation and ADP-ribosylation of CD38, intracellular concentrations of cADPR and Ca2+ and insulin secretion were measured following incubation of mouse pancreatic islet cells with NAD, ADP-ribosylation of CD38 inactivated its ecto-enzyme activities, and abolished glucose-induced increase of cADPR production, intracellular concentration of Ca2+, and insulin secretion. Taken together, ecto-cyclase activity of CD38 to produce intracellular cADPR seems to be indispensable for insulin secretion. (C) 2001 Academic Press.
NF-κB-dependent lymphocyte hyperadhesiveness to synovial fibroblasts by hypoxia and reoxygenation:: potential role in rheumatoid arthritis
No full textHypoxia/reoxygenation has been incriminated as a major factor in the pathogenesis of ischemia/reperfusion injury in various ischemic diseases such as rheumatoid arthritis (RA). In this study, we have investigated the effect of hypoxia/ reoxygenation on the expression of intercellular adhesion molecule-1 (ICAM-1) in synovial fibroblasts and adherence of lymphocytes to synovial fibroblasts. Hypoxia/reoxygenation strongly activated nuclear factor-kappaB (NF-kappaB) in synovial fibroblasts to the levels produced by phorbol 12-myristate 13-acetate and caused lymphocyte hyperadhesiveness to synovial fibroblasts as well as up-regulation of ICAM-1, both of which were completely blocked by a NF-kappaB antagonist (pyrrolidine dithiocarbamate). These results indicate that hypoxia/reoxygenation has a major role in sequestration of inflammatory cells to synovium. mediated by the activation of NF-kappaB. Our data suggest that hypoxia/ reoxygenation could be an important target for the development of new, therapeutic strategies in RA. J. Leukoc. Biol. 73: 525-529; 2003.
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