Showing papers by "Henan Normal University published in 2002"
TL;DR: Values of R = sigma(e(+e(-)-->hadrons)/sigma( e(+)e (-)-->mu(+)mu(-)) for 85 center-of-mass energies between 2 and 5 GeV measured with the upgraded Beijing Spectrometer at the Beijing Electron-Positron Collider are reported.
Abstract: We report values of $R\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{\sigma}({e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\mathrm{hadrons})/\ensuremath{\sigma}({e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})$ for 85 center-of-mass energies between 2 and $5\mathrm{GeV}$ measured with the upgraded Beijing Spectrometer at the Beijing Electron-Positron Collider.
239 citations
TL;DR: In this paper, the viscosities of glycine, α-alanine, dl-amino-n -butyric acid, Dl-valine and Dl -leucine have been determined in water-sodium acetate mixtures at 298.15 and 308.15 K. The results have been interpreted in the light of the solute-solvent interactions in aqueous media.
95 citations
TL;DR: In this paper, the existence and uniqueness results for large positive solutions are obtained for a class of quasilinear elliptic eigenvalue problems in general bounded smooth domains via a generalization of a sweeping principle of Serrin.
58 citations
TL;DR: It has been shown that the carbonyl stretch bands for PC andDEC are very sensitive to the interaction between Li+ and the solvent molecules, indicating a strong interaction of Li+ with PC and DEC through the oxygen group of PC and both oxygen and ether oxygen atoms of DEC.
58 citations
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TL;DR: In this article, the authors generalize and unify Morita contexts introduced by Chase and Sweedler, Doi and Cohen, Fischman and Montgomery, and apply their theory corings arising from entwining structures.
Abstract: Using the theory of corings, we generalize and unify Morita contexts introduced by Chase and Sweedler, Doi, and Cohen, Fischman and Montgomery. We discuss when the contexts are strict. We apply our theory corings arising from entwining structures, and this leads us to the notion of cleft entwining structure.
43 citations
TL;DR: In this paper, a reduction of phenacyl azides induced by SmI 2 was investigated and 2,4-diarylpyrroles were prepared in moderate to good yields under mild conditions.
32 citations
TL;DR: In this paper, the authors calculate the contributions of the non-universal gauge bosons Z, predicted by top-color-assisted technicolor (TC2) models and flavor-universal TC2 models, to the lepton flavor-violating tau decays τ → l i γ and τ → L i l j l k.
32 citations
TL;DR: In this article, an azobenzene derivative was synthesized and the physisorbed monolayers of the molecule at the liquid/solid interface were investigated by scanning tunneling microscopy (STM).
29 citations
TL;DR: It was observed that supplementation of CLA in the diet of laying hens decreased the concentration of oleic acid, arachidonic acid, and docosahexaenoic acid but increased that of linolenic acid and stearic acid in the egg yolk, suggesting that CLA may inhibit Delta6 and Delta9 desaturases.
Abstract: The incorporation pattern of conjugated linoleic acids (CLA) isomers into the egg yolk of hens in relation to that in the diet was studied. Silver-ion high-performance liquid chromatography (Ag-HPLC) was used to separate individual CLA isomers. It was found that the isomeric distribution pattern in the egg yolk lipids was different from that in the dietary fat. Total cis/trans isomers accounted for 81.2% of total CLA incorporated into the egg yolk, which was in contrast to the value of 92.0% of total CLA in the diet. Total cis/cis isomers accounted for 3.8% total CLA in the diet but they were 6.6% of the total CLA in the egg yolk lipids. In contrast, total trans/trans isomers were 12.2% of the total CLA isomers in the egg yolk lipids, whereas they were only 4.2% of total CLA in the diet. The results showed that total trans/trans-CLA was preferentially incorporated into the egg yolk, whereas the incorporation of total cis/trans-CLA isomers was partially discriminated. Within each group, the incorporation of individual isomers into the egg yolk lipids was also selective. cis-9,trans-11/trans-9,cis-11 and cis-10,trans-12/trans-10,cis-12 were the two major isomers in the diet. Ag-HPLC analysis showed that the former was preferentially transferred into the egg yolk compared with the latter. It was observed that supplementation of CLA in the diet of laying hens decreased the concentration of oleic acid (18:1n-9), arachidonic acid (20:4n-6), and docosahexaenoic acid (22:6n-3) but increased that of linolenic acid (18:3n-3), stearic acid (18:0), and palmitic acid (16:0) in the egg yolk, suggesting that CLA may inhibit Delta6 and Delta9 desaturases.
29 citations
TL;DR: In this article, the BESII detector operated at the BEPC has been used to measure the cross sections for e{sup +}e{sup -} {yields} hadrons, {pi}{sup+} {pi+{pi} = J/{psi} = 85.4 {+-} 8.7 keV; and corresponding branching fractions have been determined.
27 citations
TL;DR: In this article, a model is proposed to describe the relationship between positron short lifetime component τ 1 and the concentrations of oxygen vacancy and twin boundary, and the experimental results can be satisfactorily explained by this model.
Abstract: A series of YBa 2 Cu 3− x Co x O y ( x =0–0.50) samples have been studied by means of SEM, TEM, XRD and positron annihilation technology. Oxygen contents of the samples have been measured using a new volumetric method. The microstructure evolution of the Co-doped YBCO is very similar to that in the Fe-doped YBCO. YBa 2 Cu 3− x Co x O y undergoes a structure phase transition from orthorhombic to tetragonal between x =0.12 and 0.15. Twin structure predominates when x is low ( x x , tweed structure appears and its proportion increases till it becomes dominant. When x >0.12, the tweed structure disappears completely. The grain boundary density increases with x and shows a sudden drop when x >0.12. Similarly, the positron short lifetime component τ 1 shows a sudden drop between x =0.12 and 0.15. Therefore, positron can be used as a sensitive probe for the O–T phase transition in this system. A possible model is proposed to describe the relationship between positron short lifetime component τ 1 and the concentrations of oxygen vacancy and twin (tweed) boundary. The experimental results can be satisfactorily explained by this model.
TL;DR: In this paper, the structure of positive solutions to quasilinear elliptic problems is studied when λ is sufficiently large, for a class of logistic-type nonlinearities satisfying that f(0) = f(a) = 0, a > 0, f(u) > 0 for u ∈ (0,a), while u = a is a zero point of f with order ω.
Abstract: The structure of positive solutions to the quasilinear elliptic problems
–div(|Du|p–2Du = λf(u) in Ω, u = 0 on ∂Ω,
p > 1, Ω ⊂ RNa bounded smooth domain, is precisely studied when λ is sufficiently large, for a class of logistic-type nonlinearities f(u) satisfying that f(0) = f(a) = 0, a > 0, f(u) > 0 for u ∈ (0,a), , while u = a is a zero point of f with order ω. It is shown that if ω ≥ p – 1, the problem has a unique positive solution uλ with sup Ωuλ < a, which develops a boundary layer near ∂Ω. It is shown that if 0 < ω < p – 1, the problem also has a unique positive solution uλ, but the flat core {x ∈ Ω : uλ(x) = a} ≠ ∅ exists. Moreover, the asymptotic behaviour of the flat core is studied as λ → ∞.
TL;DR: In the framework of the minimal supersymmetric model, the Z-peak constraints on the scenario of one light bottom squark and light gluino is examined, which has been successfully used to explain the excess of bottom quark production in hadron collisions.
Abstract: In the framework of the minimal supersymmetric model we examine the Z-peak constraints on the scenario of one light bottom squark (sbottom) (similar to2-5.5 GeV) and light gluino (similar to12-16 GeV) which has been successfully used to explain the excess of bottom quark production in hadron collisions. Such a scenario is found to be severely constrained by the CERN LEP Z-peak observables, especially by R-b, due to the large effect of gluino-sbottom loops. To account for the Rb data in this scenario, the other mass eigenstate of sbottom, i.e., the heavier one, must be lighter than 125 ( 195) GeV at 2sigma(3sigma) level, which, however, is disfavored by CERN LEP II experiments.
TL;DR: In this article, a new synthesized chromogenic reagent N-dodecyl-N′-(sodium p-amino-benzenesulfonate)-thiourea (DOPT) was developed for determination of copper and palladium.
Abstract: Highly sensitive spectrophotometric methods for determination of copper and palladium by a new synthesized chromogenic reagent N-dodecyl-N′-(sodium p-amino-benzenesulfonate)-thiourea (DOPT) were developed. In the presence of CTMAB and NaAc-HAc buffer solution, under the optimum conditions for color reaction of copper and palladium with DOPT, their molar absorptivities are e300.4 nm = 1.56 × 105 l mol−1 cm−1 at 300.4 nm for copper and e296.0 nm = 7.41 × 104 l mol−1 cm−1 at 296.0 nm for palladium. Microamounts of copper and palladium in samples were satisfactorily determined by the methods.
TL;DR: In this paper, a simple and highly sensitive kinetic fluorimetric method is proposed for the determination of trace tannins, based on the activation of tannin on the oxidation of rhodamine 6G (Rh 6G) by hydrogen peroxide catalyzed by Cu(II) ion.
TL;DR: In this article, the authors calculate the lepton flavor violating (LFV) Z → l i l j decays and find that the extra U (1) gauge boson Z can give significant contributions to these LFV processes.
TL;DR: In this paper, aryl methyl ketones are added to the reaction mixture prior to protonation, and the desired 2,4-diarylquinolines can be obtained in moderate yields under mild conditions.
TL;DR: In this article, a non-liquid-junction electrochemical cell composed of a potassium ion selective electrode (K-ISE) against a chloride ion selective electrodes (Cl-ISE as a reference electrode was employed to study the thermodynamic parameters of weak interactions between aqueous cesium chloride and the monosaccharides (d -glucose, d -galactose,d -xylose, and d -arabinose) at T=298.15 K.
TL;DR: In this article, a Hopf algebra with invertible antipode, a Yetter-Drinfeld module algebra and the category of Hopf YetterDrinfeld -module is discussed when the category is braided monoidal.
Abstract: Let be a Hopf algebra with invertible antipode, a Yetter-Drinfeld module algebra and the category of Hopf Yetter-Drinfeld -module. In this note it is discussed when the category is braided monoidal. In fact the following is proved: assume that is -commutative. Then the braiding on the category of Yetter-Drinfeld modules induces a braiding on if and only if every object of is dyslectic.
TL;DR: In this article, the stoichio metry of gallium (III) was determined on the basis of slope analysis and IR spectra, and the authors compared the extraction characteristics among carboxylic acids (NA, CA-12 and CA-100) in kerosene and acidic aqueous chloride media.
Abstract: The extraction behavior and mechanism of gallium(III) with Naphthenic Acid (NA), Sec-octylphenoxy acetic Acid (CA-12) and Sec-nonylphenoxy acetic Acid (CA-100) from hydrochloric acid solution was studied. The distribution equilibria of gallium (III) between carboxylic acids (NA, CA-12 and CA-100) dissolved in kerosene and acidic aqueous chloride media has been investigated as a function of the concentration of extractants in organic phase and concentration of hydrogen ion in aqueous phase. To get further information, we compared the extraction characteristics among NA, CA-12 and CA-100. The stoichio metry of the extracted species is determined on the basis of slope analysis and IR spectra. Gallium is extracted by a cation exchange mechanism as Ga(OH)R2·2HR by NA and as GaR3·HR by CA-12 and CA-100.
TL;DR: A chemiluminescence (CL) system for metoclopramide combined with a flow-injection system is presented in this article, which is based on CL produced by the oxidation of metocarboxylic acid by permanganate.
Abstract: A chemiluminescence (CL) system for metoclopramide combined with a flow-injection system is presented in this paper. It is based on CL produced by the oxidation of metoclopramide by permanganate. It was found that formaldehyde could highly enhance the CL intensity. The method permits the determination of metoclopramide over a concentration range of 0.06–60 µg/mL with the detection limit (signal/noise) of 0.03 µg/mL. The relative standard deviation (RSD) for 2 µg/mL metoclopramide standard solution was 1.6% (n = 11). The method has been applied successfully to the determination of metoclopramide in tablets and injections.
TL;DR: In this article, a recurrent method for constructing the generalized Hadamard matrices D(rm(r+1),rm( r+1);p), m⩾1, has been given under the condition that both D(r,r;r) and D(m+1,r+ 1;p) are known.
TL;DR: Wang et al. as discussed by the authors investigated the shedding of tumor necrosis factor receptor 1 (TNFR1) in liver regeneration and its mechanism to regulate this shedding process, and the relationship between shedding and apoptosis of hepatocytes induced by TNFα was studied by detecting apoptotic index.
Abstract: AIM: Liver regeneration is associated with apoptosis of hepatocytes, which is mediated via tumor necrosis factor receptor 1(TNFR1). The shedding of TNFR1 in liver regeneration and its mechanism to regulate this shedding were investigated.
METHODS: The shedding of TNFR1 in liver regeneration and changes of TNF-α, PMA and plasma membrane purified from hepatocytes on this shedding process were measured with Western blot. Then, the relationship between TNFR1 shedding and apoptosis of hepatocytes induced by TNFα was studied by detecting apoptotic index.
RESULTS: The shedding of TNFR1 began at 4 hours and terminated before 2 months after partial hepatectomy. In culture system, serum from rats at 36 h after partial hepatectomy could also promote this shedding process. With the stimulation of TNF α, PMA or purified plasma membrane from hepatocytes at 36 h after partial hepatectomy or from hepatocytes treated with TNF α for 2 h, membranous TNFR1 was also shed. With the stimulation of both TNF α and plasma membrane from hepatocytes affected with TNF α for 2 h or from hepatocytes at 36 h after partial hepatectomy, apoptotic index of hepatocytes decreased from 21% to 7.52% and 8.45%, respectively. PMA could also reduce apoptotic index to 13.67%. This descent occurred in hepatocytes cultured in serum from rats at 36 h after partial hepatectomy too, but not in serum from rats at 2 months after partial hepatectomy and sham-operated rats.
CONCLUSION: Shedding of TNFR1 may help reduce apoptosis of hepatocytes induced by TNF α. Membrane-anchored metalloprotases could play a role in shedding membranous TNFR1. At the same time, PKC may take part in regulation of this shedding process.
TL;DR: In this article, an efficient synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives using samarium chloride as a catalyst from aldehyde, β-keto ester and urea or thiourea in ethanol is described.
Abstract: An efficient synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives using samarium chloride as a catalyst from aldehyde, β-keto ester and urea or thiourea in ethanol is described; compared to the ...
TL;DR: In this article, a neutral toppion production process was proposed in the framework of top-color-assisted technicolor (TC2) model, and the results showed that the production cross section of $e^{-}gamma\to e^{-}\Pi^{0}_{t}$ can reach the level of several tens fb, and over $10^{3}$ neutral toppions can be produced in the planned linear colliders each year.
Abstract: In the framework of topcolor-assisted technicolor(TC2) model, we study a neutral toppion production process $e^{-}\gamma\to e^{-}\Pi^{0}_{t}$ in this paper. Our results show that the production cross section of $e^{-}\gamma\to e^{-}\Pi^{0}_{t}$ can reach the level of several tens fb, and over $10^{3}$ neutral toppion events can be produced in the planned $e^+e^-$ linear colliders each year. Therefore, such a toppion production process provides us a unique chance to detect toppion events and test the TC2 model. On the other hand, the cross section of $e^{-}\gamma\to e^{-}\Pi^{0}_{t}$ is about one order of magnitude larger than those of some similar processes in SM and MSSM(i.e., $e^{-}\gamma\to e^{-}H$ in SM and $e^{-}\gamma\to e^{-}H^{0}(A^0,h^0)$ in MSSM). So, we can easily distinguish the neutral toppion from other neutral Higgs bosons in SM and MSSM.
TL;DR: In this paper, a poly(4-aminopyridine) modified electrode (POAPE) was deposited on the surface of glassy carbon electrode (GCE) by the electrooxidation of 4-amino acid.
Abstract: A novel Poly(4-aminopyridine) modified electrode (POAPE) was deposited on the surface of glassy carbon electrode (GCE) by the electrooxidation of 4-aminopyridine. The POAPE exhibited an excellent electrocatalytic activity toward uric acid (UA) oxidation and marked enhancement of the current response. The lifetime of this modified electrode was more than two years. The oxidation overpotential of UA at the POAPE was reduced by 160 mV compared with a bare GCE. The POAPE could be used for the determination of uric acid (UA) in the presence of 1000-fold excess of ascorbic acid (AA) with multiple semi-differential voltammetry. The oxidation peak current was proportional to the concentration of UA over the range of 5.0 × 10−9–8.0 × 10−6 M. The detection limit had been estimated as 1.0 × 10−9 M (S/N = 3). The POAPE showed a high sensitivity and selectivity for UA oxidation. The proposed procedure was utilized to determine UA in human urine without any pretreatment.
TL;DR: A new method is used to analyze the nature and preference of collaboration based on an extended database and observed values of two- three- and four-dimensional collaboration were compared respectively with their expected values.
Abstract: This paper is the continued study on age structure of scientific collaboration in Chinese computer science. Based on an extended database a new method is used to analyze the nature and preference of collaboration. Observed values of two- three- and four-dimensional collaboration were compared respectively with their expected values. Investigation covered co-authors" combination patterns, name permutations in their papers, especially the age of the first author.
TL;DR: In this article, the authors calculate the associated production of the neutral top pion with a pair of top quarks via the process and find that the production cross section is larger than that of the process in the standard model (SM) and in the minimal supersymmetric SM.
Abstract: In the context of top-color-assisted technicolor (TC2) models, we calculate the associated production of the neutral top pion ${\ensuremath{\pi}}_{t}^{0}$ with a pair of top quarks via the process ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}t\overline{t}{\ensuremath{\pi}}_{t}^{0}.$ We find that the production cross section is larger than that of the process ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}t\overline{t}H$ both in the standard model (SM) and in the minimal supersymmetric SM. With reasonable values of the parameters in TC2 models, the cross section can reach 20 fb. The neutral top pion ${\ensuremath{\pi}}_{t}^{0}$ may be directly observed via this process.
TL;DR: The S-S bond in disulfides was reduced by the Zn/ZrCl 4 system in THF to produce sulfur anions, which react with alkyl halides, α,β-unsaturated esters and acyl chlorides or anhydrides to afford unsymmetrical sulfides, thioesters and β-thioesters, respectively as mentioned in this paper.
Abstract: The S-S bond in disulfides was reduced by the Zn/ZrCl 4 system in THF to produce sulfur anions, which react with alkyl halides, α,β-unsaturated esters and acyl chlorides or anhydrides to afford unsymmetrical sulfides, thioesters and β-thioesters, respectively.
TL;DR: Fas ectodomain shedding might be an important mechanism in controlling hepatocyte apoptosis during liver regeneration, and the expression of Fas mRNA and Fas protein did not affect the liver regeneration.
Abstract: On the basis of comprehending several membrane proteins undergoing ectodomain shedding, including tumor necrosis factor (TNF) α receptors, we want to know if Fas (CD95/APO-1), which belongs to the TNF receptor (TNFR) superfamily and transduces signals resulting in apoptosis upon binding of Fas ligand (L) or agonistic anti-Fas antibody, is shed on its ectodomain during liver regeneration Methods: After purification of the total membrane protein of hepatocytes, we analyzed Fas ectodomain shedding, using Western blotting, and determined the effect of Fas shedding on the apoptosis of hepatocytes by a statistical method relevant to apoptosis. Results: Fas protein ectodomain shedding occurred at 2, 12, and 36 h after partial hepatectomy, and its level decreased at 2 months after partial hepatectomy. The same results were gained from in-vitro cultured hepatocytes induced by serum from rats after partial hepatectomy. The sensivitity of hepatocytes to agonistic anti-Fas antibody increased significantly after they were treated with serum from rats after partial hepatectomy. However, the expression of Fas mRNA and Fas protein did not affect the liver regeneration. Conclusions: Fas ectodomain shedding might be an important mechanism in controlling hepatocyte apoptosis during liver regeneration.