65 research outputs found
Twist-3 Distribute Amplitude of the Pion in QCD Sum Rules
We apply the background field method to calculate the moments of the pion
two-particles twist-3 distribution amplitude (DA) in QCD sum
rules. In this paper,we do not use the equation of motion for the quarks inside
the pion since they are not on shell and introduce a new parameter to
be determined. We get the parameter in this approach. If
assuming the expansion of in the series in Gegenbauer polynomials
, one can obtain its approximate expression which can be
determined by its first few moments.Comment: 12 pages, 3 figure
HighPâTNano-Mechanics of Polycrystalline Nickel
We have conducted highPâTsynchrotron X-ray and time-of-flight neutron diffraction experiments as well as indentation measurements to study equation of state, constitutive properties, and hardness of nanocrystalline and bulk nickel. Our lattice volumeâpressure data present a clear evidence of elastic softening in nanocrystalline Ni as compared with the bulk nickel. We show that the enhanced overall compressibility of nanocrystalline Ni is a consequence of the higher compressibility of the surface shell of Ni nanocrystals, which supports the results of molecular dynamics simulation and a generalized model of a nanocrystal with expanded surface layer. The analytical methods we developed based on the peak-profile of diffraction data allow us to identify âmicro/localâ yield due to high stress concentration at the grain-to-grain contacts and âmacro/bulkâ yield due to deviatoric stress over the entire sample. The graphic approach of our strain/stress analyses can also reveal the corresponding yield strength, grain crushing/growth, work hardening/softening, and thermal relaxation under highPâTconditions, as well as the intrinsic residual/surface strains in the polycrystalline bulks. From micro-indentation measurements, we found that a low-temperature annealing (T < 0.4 Tm) hardens nanocrystalline Ni, leading to an inverse HallâPetch relationship. We explain this abnormal HallâPetch effect in terms of impurity segregation to the grain boundaries of the nanocrystalline Ni
Meta-analysis of adherence to highly active antiretroviral therapy in patients with 55 HIV infection in China
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.With the widespread implementation of antiretroviral therapy in many countries, the HIV/AIDS epidemic has declined. However, little is known about the prevalence of adherence rate to Highly Active Antiretroviral Therapy (HAART) in patients with HIV infection in China. We conducted the first meta-analysis of cross-sectional studies of treatment adherence ( 95%) to HAART in Chinese patients. Both English (PubMed, PsycINFO, Embase, and Web of Science) and Chinese (WanFang Database, CNKI, and SinoMed) databases were systematically and independently searched by three investigators. Studies with adherence rate estimates of HAART were included. Adherence rate estimates of each eligible study were extracted and pooled using the random-effects model. A total of 40 studies conducted in China were eligible and analyzed. The mean rate of 95% HAART adherence was 81.1% (95%CI: 75.1%- 88.0%, I2 = 97.3%) at one week, 80.9% (95%CI: 74.7%- 85.9%, I2 =96.6%) at one month, and 68.3% (95%CI: 46.1%- 84.4%, I2 = 97.1%) at 3 months or longer. Subgroup analyses revealed that samples with no gender predominance, low education level, middle economic region, rural area, older age (42.3 years or older), recent publication year (2013 or later) were correlated to higher HAART adherence. The average rate of HAART adherence was relatively high in China, which suggests effective HIV/AIDS prevention and control measures and policy. However, the level of HAART adherence tended to decrease over the treatment course
Informed Consent and Ethical Review in Chinese Human Experimentation: Reflections on the âGolden Rice Eventâ
Synergistic Inhibition of Acetylcholinesterase by Alkaloids Derived from Stephaniae Tetrandrae Radix, Coptidis Rhizoma and Phellodendri Chinensis Cortex
Alkaloids having acetylcholinesterase (AChE) inhibitory activity are commonly found in traditional Chinese medicine (TCM); for example, berberine from Coptis chinensis, galantamine from Lycoris radiata, and huperzine A from Huperzia serrata. In practice of TCM, Stephaniae Tetrandrae Radix (STR) is often combined with Coptidis Rhizoma (CR) or Phellodendri Chinensis Cortex (PCC) as paired herbs during clinical application. Fangchinoline from STR and coptisine and/or berberine from CR and/or PCC are active alkaloids in inhibiting AChE. The traditional usage of paired herbs suggests the synergistic effect of fangchinoline–coptisine or fangchinoline–berberine pairing in AChE inhibition. HPLC was applied to identify the main components in herbal extracts of STR, CR, and PCC, and the AChE inhibition of their main components was determined by Ellman assay. The synergism of herb combination and active component combination was calculated by median-effect principle. Molecular docking was applied to investigate the underlying binding mechanisms of the active components with the AChE protein. It was found that fangchinoline showed AChE inhibitory potency; furthermore, fangchinoline–coptisine/berberine pairs (at ratios of 1:5, 1:2, 1:1, and 2:1) synergistically inhibited AChE; the combination index (CI) at different ratios was less than one when Fa = 0.5, suggesting synergistic inhibition of AChE. Furthermore, the molecular docking simulation supported this enzymatic inhibition. Therefore, fangchinoline–coptisine/berberine pairs, or their parental herbal mixtures, may potentially be developed as a possible therapeutic strategy for Alzheimer’s patients
Influence of Polycarboxylate Dispersants with Different Molecular Structures on the Performance of Coal Water Slurry
Laboratory Study on EOR in Offshore Oilfields by Variable Concentrations Polymer Flooding
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