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Abstract  

The purpose of this note is to show that there exist two Tychonoff spaces X, Y, a subset A of X and a subset B of Y such that A is weakly almost Lindelf in X and B is weakly almost Lindelf in Y, but A B is not weakly almost Lindelf in X Y.

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Abstract  

Some characterizations of S-paracompact spaces are given. We introduce a class of S-expandable spaces and study topological properties of S-expandable spaces.

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Both melatonin and leptin show a circadian variation in circulating levels and participate in energy metabolism. An interrelationship between these two hormones has thus been proposed. In addition, melatonin has been shown to be capable of influencing circulating leptin concentration. However, whether melatonin will increase or decrease leptin production is still uncertain. This study was undertaken to examine the effect of melatonin on leptin production using male C57BL/6 adult mice treated with or without daily melatonin supplements (10 μg/mL) in drinking water for 1 month. In addition, in vitro experiments using adipose tissue fragments derived from epididymal fat pads of adult mice incubated with or without melatonin (1 nM) administration were also conducted. The results showed that melatonin-supplemented mice had significantly higher plasma leptin levels than control mice. However, melatonin incubation did not cause any marked changes in the amount of leptin secreted from adipose tissue fragments. Our findings from this study indicate that melatonin does not affect leptin secretion via mouse adipose tissue. Nevertheless, melatonin could still influence leptinemia indirectly via regulatory effects in intact animals.

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Abstract  

This paper presents a rapid and quantitative radiochemical separation method for the Pu, Am and Cm isotopes with an anion exchange resin and a TRU resin. After the Pu isotopes were purified with an anion exchange resin method and the Am and Cm isotopes were purified with the TRU resin method, micro-coprecipitation method was applied for an alpha-source preparation. The activity concentrations and activity ratios for the Pu, Am and Cm isotopes in a radioactive sample were measured by radiation counting methods such as an alpha-spectrometry and a liquid scintillation counting as well as by a mass spectroscopic method such as a thermal ionization mass spectrometry.

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Abstract  

In this work, an easy, fast and reliable measurement technique for the quantitative determination of retained fission gases in an irradiated oxide fuel was developed. Many experiments were conducted to determine the optimum conditions for fusion of an oxide fuel, for the quantitative collection and measurements of the released gases. Ion implantation technology was applied to make a krypton or xenon references in a solid matrix. A fragment of oxide fuel, about 0.1 g of an unirradiated SIMFUEL, was completely fused with excess metallic fluxes, 1.0 g of nickel and 1.0 g of tin, in a graphite crucible of a helium atmosphere for 120 s at 850 A as a mixture of metals and alloys. About 96 ± 3 to 98 ± 4% of the krypton and xenon that were injected into the instrument using a standard gas mixture was reproducibly recovered by collecting the releasing gas through the instrument for 120 s. Using the same fusion and collection conditions, it was possible to recover about 97 ± 3% of the injected krypton and xenon by fusing a fragment of SIMFUEL which was wrapped with krypton or xenon implanted aluminum foils. The recovery test results of krypton and xenon using ion planted aluminum foils gave encouraging results suggesting their potential use as a reference specimen. It was confirmed that a fragment of irradiated oxide fuel, 0.051 g, with a code burn-up of 56.9 MWd/MtU, was completely fused as the mixture of metals and alloys through the fusion conditions and more than 99% of the retained fission gases were recovered during the first fusion. Since no cryogenic trap was needed, the collected gas could be measured directly and thus the analysis time could be further reduced. Approximately 7 min was sufficient to finish the measurement of retained fission gases in the irradiated oxide fuel using the developed procedure.

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Barley yellow dwarf virus-GAV (BYDV-GAV) is one of the most serious viruses on wheat in China. In this study, five BYDV-GAV isolates collected from five regions in Northwestern China were sequenced. The complete genome sequences generated in this study along with nine genome sequences of BYDV-GAV isolates available in GeneBank were compared and analyzed. The comparative analysis indicated that the complete genomes of BYDV-GAV showed a low level of genetic diversity with nucleotide sequence identities ranging between 97.0% and 99.7%, and the RNA-dependent RNA polymerase gene (ORF1 + ORF2) was the most variable within the complete genome. Phylogenetic analysis indicated that the BYDV-GAV isolates in Northwestern China could be divided into two groups. In addition, two potential recombination events were detected among the 14 BYDV-GAV isolates. This study provided a detailed description of molecular characterization of BYDV-GAV in Northwestern China based on the complete genome sequences, which increased the understanding of genetic diversity of barley yellow dwarf viruses.

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Zinc (Zn) has the potential of regulating the action of thiazolidinedione (TZD), an anti-diabetic drug. Since some diabetic patients cannot achieve optimal glycemic control when receiving TZD, we investigated if Zn deficiency affects TZD’s efficacy in glucose metabolism. Diabetic mice were fed diets containing 3 or 30 mg/kg Zn for 6 weeks. Thereafter, all mice were oral gavaged with 2,4-thiazolidinedione. Our results showed that blood glucose values at fasting and during the glucose tolerance test were significantly higher in low-Zn mice than those of adequate-Zn mice. Thus, low Zn intake may attenuate TZD’s efficacy on reducing diabetic hyperglycemia.

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Background and aims

Sedentary lifestyles have recently been identified as potential mechanism for obesity and associated metabolic diseases linked to ill health. The aim of this study was to investigate the effects of standing and sitting–standing positional changes on energy cost and consequently interrupting sedentary sitting time while working.

Methods

A total of 26 healthy male volunteers performed normal typing and editing work for 100 min under three conditions. The conditions included sustained sitting, sustained standing, and sitting–standing alternation every 20 min using a sit–stand desk. Respiratory parameters measured included minute ventilation (VE), oxygen consumption (VO2), and energy expenditure (EE). Measurements were recorded using a calibrated Cosmed K4b2 portable gas analysis system.

Results

The mean value for VE was the highest in the standing position (VE = 13.33 ± 0.71), followed by sitting–standing alternation (VE = 12.04 ± 0.62). Both were significantly different from sitting (VE = 10.59 ± 0.69). The maximum VE and EE for standing (VE = 14.81 ± 0.43 and EE = 1.84 ± 0.10) and sitting–standing alternation (VE = 14.80 ± 0.40 and EE = 1.93 ± 0.08) were significantly higher than that of sitting (VE = 12.15 ± 0.42 and EE = 1.67 ± 0.07). No significant differences were observed in the mean VO2 among the three conditions. However, the maximum VO2 for both standing (VO2 = 5.40 ± 0.20) and sitting–standing alternation (VO2 = 5.14 ± 0.17) had shown to be significantly higher than sitting (VO2 = 4.50 ± 0.18). There were no significant differences observed in the mean EE levels between sitting (EE = 1.43 ± 0.07) and sitting–standing alternation (EE = 1.55 ± 0.08). However, the mean EE while standing (EE = 1.62 ± 0.09) significantly increased compared to sitting.

Conclusions

The findings of this study indicate that sitting–standing alternations may be implemented as an effective intervention to interrupt prolonged sitting while working.

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Summary  

PM10 and PM2.5 samples were collected simultaneously in Beijing, China, and analyzed by INAA and ICP-MS. Seasonal variations of the concentrations of ambient particles and their elemental compositions were found. The main sources of PM10 and PM2.5 in spring were the crust, coal burning and vehicle exhaust, in which the former was significant. During a strong dust storm, the concentrations of the crustal elements in PM10 and PM2.5 increased remarkably, but the concentrations of some anthropogenic elements decreased. The enrichment factors of these anthropogenic elements also decreased sharply during the dust storm, which indicated that they were mostly originated from local anthropogenic pollution and diluted by the huge amount of dust.

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Some wild species of the genus Oryza such as O. rufipogon and O. longistaminata show a high level of resistance to pests and diseases including rice blast (caused by Magnaporthe grisea). To transfer blast resistance from wild species into cultivatedvarieties (O. sativa), interspecific hybrids were produced and anther culture was used toaccelerate the procedure of resistance breeding. Anther culture efficiency depended onboth the medium and the genotype of the cultivated varieties and the wild species. Afterinoculation with a mixture of six strains with wide spectrum virulence, all the F1 hybridswere resistant to blast; the F2 plants segregated, from high resistance to susceptibility, anda similar result was obtained for the H1 and H2 plants. At the H3 stage, blast resistancetended to be stable and almost 100% of inoculated H5 plants were highly resistant to riceblast. For agronomic characteristics, the F2 and H1 showed segregation, but no significantdifferences were seen between the cultivated parents and the H2 to H5 generations. Theresults demonstrate that blast resistance genes can be transferred from wild rice speciesinto cultivated varieties through crossing and anther culture, and the H5 can be used asstable lines in future breeding programmes.

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