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Half Times (half + time)
Selected AbstractsWide-bore hydrodynamic chromatography in sub-second rangeJOURNAL OF SEPARATION SCIENCE, JSS, Issue 3 2009Ryoji Umehara Abstract Wide-bore hydrodynamic chromatography (HDC) is a very simple method based on the passage of analytes through an open capillary. As shown in previous papers, an analyte, which diffuses over the entire cross-section of a capillary before it is detected, gives a Gaussian-shaped peak; such an analyte is called diffusive. In contrast, an analyte with poor diffusivity gives an asymmetrical peak with the apex at the half time of the peak of a diffusive analyte. Their diffusivity is determined by the diffusion coefficients, dimensions of a capillary, and a flow rate. A consideration of the diffusivity evaluated on the basis of these variables allows us to realize fast wide-bore HDC separation. Sub-second separation is demonstrated using test analytes, such as fluorescein and polystyrene latexes. [source] Influence of lanthanum stearate on the crystallization behavior of isotactic polypropyleneASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009Xiaojing Guo Abstract The influence of a nucleating agent, lanthanum stearate (LaSt), on the crystallization behavior of isotactic polypropylene (iPP) was investigated using differential scanning calorimetry (DSC), polarized optical microscopy (POM) and wide-angle x-ray scattering (WAXD). It was found that LaSt can act as a ,-nucleating agent and induce the formation of a high content of ,-form during the crystallization of iPP. The content of ,-form is greatly affected by crystallization temperature and cooling rate. High crystallization temperature and low cooling rate are favorable to the formation of ,-form. The results of isothermal crystallization kinetics show that LaSt shortens the crystallization half time (t1/2) and accelerates the crystallization of iPP. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Pre-steady state kinetics of ATP hydrolysis by Na,K-ATPaseCELL BIOCHEMISTRY AND FUNCTION, Issue 3 2009Nikhat Manzoor Abstract Fast reaction kinetics of ATP hydrolysis by Na,K-ATPase has been investigated by following absorption pattern of pH sensitive dye in stopped flow spectrophotometer. Distinct pre-steady state phase signal could be recorded with an initial decrease in acidity followed by increase in acidity. Average half time for H+ absorption and peak alkalinity was, respectively, 30,ms and 60,ms. Under optimal Na+ (120,mM) and K+ (30,mM) concentrations, magnitude of both H+ absorption and H+ release are found to be about 1.0,H+/ATPase molecule. H+ absorption and release decreased with decrease in Na+ concentration, H+ release was more affected. Both H+ absorption and H+ release are found to be independent of K+ concentration in the pre-steady state phase. No H+ absorption or release was observed following mixing of either ADP, Na+ or K+ alone with ATPase. Effect of delayed mixing of Na+ or K+ on two phases of pre-steady state cycle indicates that ATP hydrolytic cycle starts without K+ ions if optimal Na+ is present. ATP hydrolytic cycle does not start in the absence of Na+ ions. Results obtained have been interpreted in terms of an extended kinetic scheme for Na,K-ATPase. Copyright © 2009 John Wiley & Sons, Ltd. [source] Peptide-coated vascular grafts: An in vivo study in sheepHEMODIALYSIS INTERNATIONAL, Issue 4 2004Cheng Li Abstract The data on function and patency of prosthetic vascular grafts in various clinical settings are limited. The purpose of this in vivo study was to compare the function and patency of P15-coated expanded polytetrafluoroethylene (ePTFE) vascular grafts to uncoated ePTFE grafts in sheep. The P15 cell-binding peptide was covalently immobilized onto the surface of ePTFE grafts by a novel atmospheric plasma coating method. We evaluated the amount of neointimal tissue ingrowth present at the arterial and venous sides of the anastomoses and the degree of endothelial cell resurfacing of the luminal surface of the graft. Four P15-coated grafts and two control grafts were implanted as arteriovenous grafts between the femoral artery and vein and the carotid artery and jugular vein in two sheep (n = 6). One animal was euthanized after 14 days and the other after 28 days. The study showed the intimal ingrowth was significantly less. The average intimal thickness of P15-coated grafts (658 µm) was approximately two and a half times less than that of uncoated samples (1657 µm). The newly formed endothelial cell lining was thicker and its coverage was more uniform for P15-coated grafts compared to the uncoated controls. [source] Distribution, Inequality and Concentration of Incomeamong Older Immigrants in CanadaINTERNATIONAL MIGRATION, Issue 1 2000K.G. Basavarajappa While there are many studies on differences in earnings between immigrants and the native-born or among immigrant groups, they do not consider distribution and concentration of income among immigrants explicitly. These aspects are important for understanding the distribution of economic welfare and consumer behaviour among members and hence are policy relevant. Using the 1991 Census data, the distribution and concentration of incomehave been examined among 15 broad birthplace groups for population aged55 years and over. About 19 per cent of males and 15 per cent of femalesreceive less than half the median income and obtain 5 per cent and 3 per centof the aggregate income respectively. About 30 per cent of males and29 per cent of females receive more than one and half times the medianincome and obtain 61 per cent and 59 per cent of aggregate incomerespectively. About 51 per cent of males and 56 per cent of females whoreceive incomes between half and one and half times the median income aretermed middle-class and their shares of aggregate income amount to 34 and38 per cent respectively. Although older immigrants aged 55 years and over, as a group, have roughlythe same quartile distribution and concentration of income as theirCanadian-born counterparts, the birthplace groups differ considerably. Those from the developing regions, that is, the groups that have loweraverage annual incomes, also have more inequitable distribution of incomethan the Canadian-born or their counterparts from the developed regions. Thus, income distribution is more polarized in populations from developingregions than in populations from developed regions or in the Canadian-bornpopulation. On average, females receive 45 per cent less income than males, and thereis less polarization of income among them than among males regardless ofthe place of birth. A part of the explanation lies in the receipt of government transfers, whichtend to equalize rather than polarize incomes, and older women derive ahigher proportion of their income from government transfers than older men. [source] Wealth Transfer Effects of Analysts' Misleading BehaviorJOURNAL OF ACCOUNTING RESEARCH, Issue 1 2007GUS DE FRANCO ABSTRACT We investigate a sample of 50 firm-events, identified in the Global Research Analysts Settlement, in which analysts were discovered to have acted misleadingly ex post. In this setting, analysts' incentives caused them to issue public disclosures that differed from their private beliefs. We document that these firms' institutional holdings decline significantly during the period in which the analysts issued misleading disclosures. During this period daily small-size trades (a proxy for individual investors) are dominated by buy orders while daily large-size trades (a proxy for institutional investors) are dominated by sell orders. Short interest increases during the event period, consistent with the idea that sophisticated investors are selling. Our estimates of investors' trading losses show that individual investors lost about two and a half times the amount lost by institutions. Overall, the results suggest a wealth transfer from individuals to institutions that is likely attributable to analysts' misleading behavior. [source] LIPOXYGENASE ACTIVITY IN PRICKLY PEAR FRUIT (OPUNTIA FICUS INDICA [L.] MILL.JOURNAL OF FOOD BIOCHEMISTRY, Issue 2 2010CACTACEAE) ABSTRACT Prickly pear LOX activity was detected in the membrane fractions of the fruit extracts at various stages of ripening. LOX specific activity was very low in the fruit of wild plants at the green stage (0.49 ± 0.04) and increased with fruit ripening, more than doubling in the ripened fruit (1.22 ± 0.06). Moreover, it was not influenced by the cultivar, whereas it was considerably increased (13.3 ± 1.4) by agronomic processes to which prickly pear plants are submitted to improve the organoleptic properties of fruits. The apparent molecular mass of the enzyme was estimated to be 96 kDa. The enzyme had an optimum pH value of 5.5 and a clear specificity for linolenic acid, which was oxidized at a rate one and a half times that of linoleic acid, under the same reaction conditions. The involvement of prickly pear LOX in the flavor biosynthesis of the fruit is supposed. PRACTICAL APPLICATIONS Over the last decade in particular, prickly pear fruits have been widely used as food, not only the whole fruit but also processed to make juices, jams and liquors popular the world over. Prickly pear production has therefore risen considerably and consequently both the labor force employed and revenues generated have increased. For those engaged in this sector it is therefore a prime objective to maximise the profile and thereby profitability of the fruit. It is here that our research into lipoxygenase activity can play a part, as it is known that this enzyme is responsible for the organoleptic properties of fruits and vegetables. The results are presented below. The relationship between lipoxygenase specific activity and specific agronomic processes utilized to improve the fruit quality is also addressed. [source] Early bone in-growth ability of alumina ceramic implants loaded with tissue-engineered boneJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2006Yasuaki Tohma Abstract To enhance early bonding of an alumina ceramic implant to bone, we evaluated a method of seeding the implant surface with bone marrow mesenchymal cells that differentiated to osteoblasts and bone matrix prior to implantation. The usefulness of the method was evaluated in Japanese white rabbits. In our study, an alumina ceramic test piece loaded with differentiated osteoblasts and bone matrix by a tissue engineering technique was implanted into rabbit bones. Three weeks after the procedure, evaluation of mechanical bonding and histological examination were performed. Histological examination of the noncell-loaded implant surfaces showed no bone infiltration into the implant gap. However, the cell-loaded implant surfaces exhibited new bone infiltration into the implant gap with mechanical bonding. In the mechanical test, the average failure load was 0.60 kgf for the noncell-loaded side and 1.49 kgf for the cell-loaded side. Preculturing mesenchymal cells on the surface of the alumina ceramic prior to implantation increased the debonding strength by two and half times. The present findings indicate early bonding between the implant and bone three weeks after the procedure. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source] Oxidative gating of water channels (aquaporins) in corn rootsPLANT CELL & ENVIRONMENT, Issue 4 2006QING YE ABSTRACT An oxidative gating of water channels (aquaporins: AQPs) was observed in roots of corn seedlings as already found for the green alga Chara corallina. In the presence of 35 m m hydrogen peroxide (H2O2) , a precursor of hydroxyl radicals (*OH) , half times of water flow (as measured with the aid of pressure probes) increased at the level of both entire roots and individual cortical cells by factors of three and nine, respectively. This indicated decreases in the hydrostatic hydraulic conductivity of roots (Lphr) and of cells (Lph) by the same factors. Unlike other stresses, the plant hormone abscisic acid (ABA) had no ameliorative effect either on root Lphr or on cell Lph when AQPs were inhibited by oxidative stress. Closure of AQPs reduced the permeability of acetone by factors of two in roots and 1.5 in cells. This indicated that AQPs were not ideally selective for water but allowed the passage of the organic solute acetone. In the presence of H2O2, channel closure caused anomalous (negative) osmosis at both the root and the cell level. This was interpreted by the fact that in the case of the rapidly permeating solute acetone, channel closure caused the solute to move faster than the water and the reflection coefficient (,s) reversed its sign. When H2O2 was removed from the medium, the effects were reversible, again at both the root and the cell level. The results provide evidence of oxidative gating of AQPs, which leads on to inhibition of water uptake by the roots. Possible mechanisms of the oxidative gating of AQPs induced by H2O2 (*OH) are discussed. [source] The prevalence of mental health problems in Ethiopian child laborersTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 9 2006Daniel Fekadu Background:, Child labor refers to a state when a child is involved in exploitative economical activities that are mentally, physically, and socially hazardous. There are no prevalence studies on the magnitude of psychiatric disorders among child laborers. Methods:, A cross-sectional population survey was conducted in Addis Ababa using the Diagnostic Interview for Children and Adolescents (DICA). Subjects were a random sample of 528 child laborers aged between 5 and 15 years and comprising child domestics, street-workers and private enterprise workers. These were compared with 472 non-economically active controls. Results:, The aggregate prevalence of any DSM-III-R childhood emotional and behavioral disorders was found to be 16.5%, with 20.1% and 12.5% among child laborers and controls respectively, OR = 1.89 (95% CI, 1.34,2.67, p < .01). Internalizing disorders such as mood disorders were significantly higher among the laborers than the non-laborers, OR = 6.65 (95% CI, 2.20,22.52, p = .0001). Anxiety disorder was seen over twofold among child laborers while psychosocial stressors were one and half times more likely among the study subjects than controls. When all factors were taken into account, child labor status was the only significant factor in determining DSM-III-R diagnosis. Conclusion:, In this study childhood emotional and behavioral disorders are found to be more common among child laborers than among non-laborers. We recommend a larger study to look into childhood disorders and risk factors in child labor. As part of the concerted effort, government, NGOs, and the public should at least view child labor as a menace in a child's development, with risk of psychosocial difficulties. [source] Pt Thin Film Collectors Prepared by Liquid-Delivery Metal,Organic CVD Using Pt(C2H5C5H4)(CH3)3 for LiCoO2 Thin Film Cathodes,CHEMICAL VAPOR DEPOSITION, Issue 6 2003W.-G. Choi Abstract Platinum thin film collectors were deposited onto p-type Si(100) planar and trench substrates by liquid-delivery metal,organic (LD-MO) CVD using Pt(EtCp)Me3, Pt(C2H5C5H4)(CH3)3, for microbatteries. The resistivity and root-mean-square (rms) roughness of Pt thin films with (111) preferred orientation increased with the increase of both deposition temperature and system pressure. The deposition of Pt thin films was controlled by a gas-phase mass-transfer mechanism and Pt thin films deposited at 350,°C showed the lowest resistivity, rms roughness, and the highest step coverage, 57,%, in trench structure. The LiCoO2 cathode films (step coverage,=,51,%) deposited on the trench Pt collector showed an increase in discharge capacity of approximately two and half times that of the planar Pt collector. Platinum thin films deposited by LD-MOCVD have a possible application as collector materials for LiCoO2 thin film cathodes. [source] | |||||||||||||