656 research outputs found
The effect of surface and Coulomb interaction on the liquid-gas phase transition of finite nuclei
By means of the Furnstahl, Serot and Tang's model, the effects of surface
tension and Coulomb interaction on the liquid-gas phase transition for finite
nuclei are investigated. A limit pressure p-lim above which the liquid-gas
phase transition cannot take place has been found. It is found that comparing
to the Coulomb interaction, the contribution of surface tension is dominate in
low temperature regions. The binodal surface is also addressed.Comment: LaTex, 8 pages with 6 fig
Improved quark mass density- dependent model with quark and non-linear scalar field coupling
The improved quark mass density- dependent model which includes the coupling
between the quarks and a non-linear scalar field is presented. Numerical
analysis of solutions of the model is performed over a wide range of
parameters. The wave functions of ground state and the lowest one-particle
excited states with even and odd parity are given. The root-mean squared
radius, the magnetic moment and the ratio between the axial-vector and the
vector beta-decay coupling constants of the nucleon are calculated. We found
that the present model is successful to describe the properties of nucleon.Comment: 7pages, 6 figure
Improved quark mass density- dependent model with quark-sigma meson and quark-omega meson couplings
An improved quark mass density- dependent model with the non-linear scalar
sigma field and the -meson field is presented. We show that the present
model can describe saturation properties, the equation of state, the
compressibility and the effective nuclear mass of nuclear matter under mean
field approximation successfully. The comparison of the present model and the
quark-meson coupling model is addressed.Comment: 15 pages, 6 figure
Effect of Baicalin on inflammatory mediator levels and microcirculation disturbance in rats with severe acute pancreatitis
Objective: To investigate the effect of Bacailin on inflammatory mediator levels and microcirculation disturbance in severe acute pancreatitis (SAP) rats and explore its therapeutic mechanism on this disease. Methods: SAP model rats were randomly divided into model control group and Baicalin treated group, 45 rats in each group. The same number of normal rats were included in sham-operated group. These groups were further subdivided into 3 h, 6 h and 12 h subgroups, respectively (15 rats in each subgroup). At 3, 6 and 12 hours after operation, rats were killed to conduct the following experiments: (1) to examine the mortality rates of rats, the ascites volume and pancreatic pathological changes in each group; (2) to determine the contents of amylase, PLA~2~, TXB~2~, PGE~2~, PAF and IL-1[beta]; in blood as well as the changes in blood viscosity.Results: (1) Compared to model control group, treatment with Baicalin is able to improve the pathological damage of the pancreas, lower the contents of amylase and multiple inflammatory mediators in blood, decrease the amount of ascitic fluid and reduce the mortality rates of SAP rats; (2) at 3 hours after operation, the low-shear whole blood viscosity in Baicalin treated group was significantly lower than that in model control group;at 12 hours after operation, both the high-shear and low-shear whole blood viscosity in Baicalin treated group were also significantly lower than those in model control group.Conclusion: Baicalin, as a new drug, has good prospects in the treatment of SAP since it can exert therapeutic effects on this disease through inhibiting the production of inflammatory mediators, lowering blood viscosity, improving microcirculation and mitigating the pathological damage of the pancreas
Bibliometric analysis of research relating to refractive cataract surgery over a 20-year period: from 2003 to 2022
AIM: To investigate the research trend on refractive cataract surgery, compare the contributions of different countries, institutions, journals, and authors in the past 20y, and explore its potential research hotspots. METHODS: All publications were extracted relating to refractive cataract surgery from 2003 to 2022 from Web of Science. Document types were limited to original articles and reviews, and the language was limited to English. Quantitatively and qualitatively of the publications were analyzed through Microsoft Excel and GraphPad Prism. VOSviewer and CiteSpace were used for bibliometric and visualized analysis. RESULTS: A total of 2090 publications were enrolled. The United States contributed the most publications (434, 20.8%), followed by China (345, 16.5%) and England (163, 7.80%). Publications from the United States were cited more frequently (9552 citations) with the highest H-index of 48. China ranked second in the total number of publications, the papers were not cited that frequently (3237 citations), and the H-index ranked sixth (H-index=29). Journal of Cataract and Refractive Surgery published the most papers (333, 15.9%), and the University of London had the highest number of publications (75, 3.59%). Dick HB from Germany published the most papers. Corneal astigmatism-related research, cataract surgery method-related research, postoperative visual-quality relate to research, and postoperative complications-relate research are the hotspots in this field. The most significant limitation was that the database was updated frequently and the latest publications were not included. CONCLUSION: The bibliometric analysis shows a brief summarization of the contribution of the authors, institutions, countries, and journals. Corneal astigmatism, cataract surgery method, postoperative visual-quality and postoperative complications related researches have become the emerging hotspots, which can give a direction in the future researches
Three-Dimensional Simulation of the Shrinkage Behavior of Injection-Molded Poly Lactic Acid (PLA): Effects of Temperature, Shear Rate and Part Thickness
The effects of injection temperature, shear and part thickness on the linear shrinkage of injection-molded poly (lactic acid) (PLA) were intensively analyzed using the Autodesk Moldflow software. The obtained results showed that both melt temperature and shear rate had obvious effects on the linear shrinkage of PLA, i.e., the linear shrinkage of PLA increases significantly with the increase of melt temperature and shear rate. In addition, the shrinkage of high-crystallinity PLA was remarkably larger than that of low-crystallinity PLA, and thin-walled parts was larger than thick-walled ones in shrinkage
β2 Adrenergic receptor activation induces microglial NADPH oxidase activation and dopaminergic neurotoxicity through an ERK-dependent/protein kinase A-independent pathway
Activation of the β2 adrenergic receptor (β2AR) on immune cells has been reported to possess anti-inflammatory properties, however, the pro-inflammatory properties of β2AR activation remain unclear. In this study, using rat primary mesencephalic neuron-glia cultures, we report that salmeterol, a long-acting β2AR agonist, selectively induces dopaminergic (DA) neurotoxicity through its ability to activate microglia. Salmeterol selectively increased the production of reactive oxygen species (ROS) by NADPH oxidase (PHOX), the superoxide-producing enzyme in microglia. A key role of PHOX in mediating salmeterol-induced neurotoxicity was demonstrated by the inhibition of DA neurotoxicity in cultures pretreated with diphenylene-iodonium (DPI), an inhibitor of PHOX activity. Mechanistic studies revealed the activation of microglia by salmeterol results in the selective phosphorylation of ERK, a signaling pathway required for the translocation of the PHOX cytosolic subunit p47phox to the cell membrane. Furthermore, we found ERK inhibition, but not protein kinase A (PKA) inhibition, significantly abolished salmeterol-induced superoxide production, p47phox translocation, and its ability to mediate neurotoxicity. Together, these findings indicate that β2AR activation induces microglial PHOX activation and DA neurotoxicity through an ERK-dependent/PKA-independent pathway
Response of Mouse Zygotes Treated with Mild Hydrogen Peroxide as a Model to Reveal Novel Mechanisms of Oxidative Stress-Induced Injury in Early Embryos
Our study aimed to develop embryo models to evaluate the impact of oxidative stress on embryo development. Mouse zygotes, which stayed at G1 phase, were treated with prepared culture medium (containing 0.00, 0.01, 0.02, 0.03, 0.04, 0.05, or 0.1 mM hydrogen peroxide (H2O2)) for 30 min in experiment 1. The dose-effects of H2O2 on embryo development were investigated via comparisons of the formation rate at each stage (2- and 4-cell embryos and blastocysts). Experiment 2 was carried out to compare behaviors of embryos in a mild oxidative-stressed status (0.03 mM H2O2) with those in a control (0 mM H2O2). Reactive oxygen species (ROS) levels, variation of mitochondrial membrane potential (MMP), expression of γH2AX, and cell apoptosis rate of blastocyst were detected. We observed a dose-dependent decrease on cleavage and blastocyst rates. Besides, higher level of ROS, rapid reduction of MMP, and the appearance of γH2AX revealed that embryos are injured early in mild oxidative stress. Additionally, γH2AX may involve during DNA damage response in early embryos. And the apoptotic rate of blastocyst may significantly increase when DNA damage repair is inadequate. Most importantly, our research provides embryo models to study cell cycle regulation and DNA damage response under condition of different levels of oxidative stress
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