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  • Author or Editor: Yu. Liu x
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Abstract  

The phase behaviour and phase stability of lipids are of importance in an understanding of the biological functions of cell membranes. Among a variety of physical techniques employed to study the phase behaviour and structural properties of polar lipids, differential scanning calorimetry and X-ray diffraction have proved to be successful and are the most frequently used methods. Applications involving a combination of the two techniques, particularly when synchrotron radiation is used as the light source of X-ray diffraction, are reviewed in this article.

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The paper focuses on the Top 500 foreign investment corporations (FICs) in China, by conducting data mining and system searching on the data-base of patent from the State Intellectual Property Office of the People's Republic of China (SIPO). Structure of patent applications, industrial distribution of patent applications, monopolistic tendency, technological innovation of Chinese companies and directions of foreign investment are studied.

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Abstract

We study global and local Q-measures, as well as betweenness centrality, as indicators of international collaboration in research. After a brief review of their definitions, we introduce the concepts of external and internal inter-group geodesics. These concepts are applied to a collaboration network of 1129 researchers from different countries, which is based on publications in bibliometrics, informetrics, webometrics, and scientometrics (BIWS in short) from the period 1990–2009. It is thus illustrated how international collaboration (among authors from different countries) in BIWS is carried out. Our results suggest that average scores for local Q-measures are typically higher, indicating a relatively low degree of international collaboration in BIWS. The dominating form of international collaboration is bilateral, whereas multilateral collaboration is relatively rare in the field of BIWS. We also identify and visualize the most important global and local actors. Dividing the entire period in four 5-year periods, it is found that most international collaboration in the field has happened in the last time slice (2005–2009). A comparison of the different time slices reveals the non-linear growth of the indicators studied and the international expansion of the field.

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Abstract

This study builds the interdisciplinary knowledge network of China, which is used to catch the knowledge exchange structure of disciplines, and investigates the evolution process from 1981 to 2010. A network analysis was performed to examine the special structure and we compare state of the networks in different periods to determine how the network has got such properties. The dataset are get from the reference relationship in literature on important Chinese academic journals from 1980 to 2010. The analytical results reveal the hidden network structure of interdisciplinary knowledge flows in China and demonstrate that the network is highly connected and has a homogeneous link structure and heterogeneous weight distribution. Through comparing of the network in three periods, that is 1981–1990, 1991–2000 and 2001–2010, we find that the special evolution process, which is limited by the number of nodes, play an important influence on interdisciplinary knowledge flows.

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Abortion in dairy cattle causes considerable economic losses to the dairy industry. Aborted fetuses and samples from the corresponding aborting dams from 12 dairy herds in Beijing were tested for 9 abortifacient infectious pathogens by PCR between 2008 and 2010. From a total of 80 abortion cases collected during this period, infectious agents were detected in 45 (56.3%) cases, 22 (48.9%) of which represented co-infections with two or three infectious agents. The detected pathogens included infectious bovine rhinotracheitis virus (36.3%) and Neospora caninum (31.3%), followed by bovine viral diarrhoea virus (7.5%), Brucella abortus (6.3%), Tritrichomonas foetus (5%) and Toxoplasma gondii (1.3%). Campylobacter fetus, Coxiella burnetii and Chlamydophila psittaci were not detected in any abortion case. Findings from this study indicated that infectious bovine rhinotracheitis virus and Neospora caninum were the main potential causes of abortions in Beijing dairy herds, whereas the bacterial pathogens were not, in contrast to reports from other countries. This is the first study to test nine abortifacient infectious agents by PCR at the same time, and it is also the first time to report the involvement of a variety of infectious agents in bovine abortion cases in China.

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In this preliminary study, we determined the effect of a modified method involving the administration of two low doses of prostaglandin F (PGF) at an interval of 24 h on luteolysis in dairy cows, and compared it with the standard single-dose method. Twenty-six cows were assigned to three groups treated with two low doses (TLD group, n = 10), one standard dose (SD group, n = 10), and one low dose (OLD group, n = 6) on day 9 to 10 of the oestrous cycle (day 0 = the day of PGF administration). Their serum progesterone (P4) levels and corpus luteum (CL) sizes were measured daily from day 0 to 4 to assess CL regression. The results indicated that the proportion of complete luteolysis, indicating a P4 value ≤ 1 ng/mL on day 3, was higher in the TLD group (100.0%) than in the SD (60.0%) and OLD (66.7%) groups. Ultrasonically detected changes in the CL area correlated with the shifts in the P4 values in both the TLD and the SD groups. The remaining CL area was significantly smaller in the TLD group (17.8% ± 3.3%) than in the SD or OLD group on day 4. Thus, we concluded that the proportion of luteolysis in cows was increased with two low doses of PGF as compared to a single PGF dose, indicating the necessity of the second dose of PGF. However, further studies with larger sample sizes in the field are required.

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Three yeasts from the genus Williopsis (W. saturnus var. mrakii NCYC500, W. saturnus var. saturnus CBS254 and W. californica NCYC2590) were examined for their ability to ferment longan juice and to enhance formation of longan wine aroma compounds. The three yeasts showed similar growth kinetics and pH changes during fermentation. W. californica was the least sugar consumer. Many of the naturally occurring volatiles (ethyl esters, fatty acids, aldehydes, and terpenes) in the juice were partially or completely degraded. The three yeasts varied with their ability to produce and utilise volatiles. Esters were the major volatiles produced with some esters being catabolised while other esters remained stable. The amount of most alcohols increased while of aldehydes decreased. W. saturnus CBS254 was the best producer of ethyl acetate, isobutyl acetate, isoamyl acetate and 2-phenethyl acetate, whereas W. californica NCYC2590 was the highest producer of butyl acetate. Ethanol was produced in similar amounts by W. mrakii and W. saturnus but at a minimal level by W. californica. W. mrakii formed the highest amount of isobutyl alcohol, isoamyl alcohol and 2-phenylethyl alcohol. Although the amounts of most of the major volatiles at the end of fermentation (day 14) differed statistically among the yeasts, it remained to be seen whether the quantitative differences can be detected organoleptically. These fi ndings suggest that yeasts from the genus Williopsis could be exploited for longan wine aroma enhancement either singly or in co-inoculation with Saccharomyces.

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Abstract  

A method for211At labeling of human IgG via DTPA anhydride is described. DTPA-IgD was prepared and211At was conjugated to human IgG by adding Na211At to the DTPA-IgG and reaction for 30 minutes at room temperature. The astatinated IgG was isolated by a Sephadex G50 column and identified by size exclusion HPLC. The labeling procedure was executed in 1.5 hours and at least 60% of the added211At was found in the product. The in vitro and in vivo stability of211At-DTPA-IgG was evaluated.

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Abstract  

Batch adsorption technique was applied to study the adsorption of radiocobalt on multiwalled carbon nanotubes (CNTs) with deferent sizes. The aim of this work was to examine the effect of contact time, pH, solid content, foreign ions and CNT particle sizes on the removal of Co(II) ions from aqueous solutions by CNTs. The results indicated that the adsorption of Co(II) was strongly dependent on pH and the adsorption capacity was in inverse proportion to the particle sizes of CNTs. The adsorption of Co(II) was weakly affected by ionic strength and foreign ions. Ion exchange and surface complexation were the main adsorption mechanisms. The kinetics of Co(II) adsorption on CNTs was described well by pseudo-second-order model. The Langmuir and Freundlich models were applied to interpret the adsorption data. The results are important to understand the physicochemical behavior of Co(II) with CNTs, and for the application of CNTs in the preconcentration of radiocobalt from large volumes of aqueous solutions.

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Abstract  

In this study, a local bentonite from Gaomiaozi county (Inner Mongolia, China) was converted to Na-bentonite and was characterized by FTIR and XRD to determine its chemical constituents and micro-structure. The removal of cobalt from aqueous solutions by Na-bentonite was investigated as a function of contact time, pH, ionic strength, foreign ions and temperature by batch technique under ambient conditions. The results indicated that the sorption of Co(II) was strongly dependent on pH. At low pH, the sorption of Co(II) was dominated by outer-sphere surface complexation or ion exchange whereas inner-sphere surface complexation was the main sorption mechanism at high pH. The Langmuir, Freundlich, and D-R models were used to simulate the sorption isotherms of Co(II) at the temperatures of 293.15, 313.15 and 333.15 K, respectively. The thermodynamic parameters (∆, ∆, ∆) of Co(II) sorption on GMZ bentonite calculated from the temperature-dependent sorption isotherms indicated that the sorption of Co(II) on GMZ bentonite was an exothermic and spontaneous process. The Na-bentonite is a suitable material for the preconcentration and solidification of Co(II) from aqueous solutions.

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