89 research outputs found

    Photoionization Studies of Intramolecular Dynamics: A Closer Look.

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    Using synchrotron radiation as an excitation source, dispersed fluorescence measurements of two different molecular systems are presented in this dissertation with the intention to study the two fundamental aspects of shape resonances-complexity and completeness. \rm C\sb6F\sb6 is a relative large and complex molecule in the sense that nonradiative transitions can take place unimolecularly in the free species. The elucidation of the ionization dynamics of this molecule helps to bridge the gap from simple molecules to matter in condensed phases. In the \rm 2a\sb{2u}\sp{-1} photoionization study of \rm C\sb6F\sb6, the non-Franck-Condon behavior of the vibrational distributions at around 20 eV indicates the existence of shape resonances in this energy range. This is the first time a shape resonance of such a complex molecule is characterized with vibrational resolution detail over such a broad energy range. While the study of \rm C\sb6F\sb6 is to disentangle the complexity aspect of shape resonance, the investigation of CO is an attempt to carry the shape resonant study to its completeness. The original goal of the 4\sigma\sp{-1} photoionization study of CO was to investigate the vibrational-rotational-electronic (V-R-E) coupling. To be specific, we intended to study the shape resonant effects on the rotational population distributions for alternative vibrational levels. While the 4σ→kσ4\sigma\to k\sigma shape resonance influences do not seem to be very significant, the results brought to attention another issue--continuum-continuum channel coupling. The study shows that the R-dependent aspects of shape-resonance-induced continuum coupling affects rotational population distributions for alternative vibrational states differently. In modern scientific researches, the development of instruments plays a critical role. The trend today is for computers to serve as the engine for instrumentation-virtual instruments. By walking through the development processes of a real-time instrument control and data acquisition system, the hardware setup as well as the software design and implementation, this dissertation intends to illustrate the advantage of virtual instruments over traditional instruments

    Quercetin Pretreatment Attenuates Hepatic Ischemia Reperfusion-Induced Apoptosis and Autophagy by Inhibiting ERK/NF- κ

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    Background. Hepatic ischemia reperfusion (IR) injury is a common phenomenon in transplantation or trauma. The aim of the present study was to determine the protective effect of quercetin (QE) on hepatic IR injury via the ERK/NF-κB pathway. Methods. Mice were randomized into the sham, IR, QE100 + IR, and QE200 + IR groups. Quercetin was administered intragastrically daily at two doses (100 mg/kg and 200 mg/kg) for 5 days prior to IR injury. The expression levels of liver enzymes, inflammatory cytokines, and other marker proteins were determined at 2, 8, and 24 hours after IR. And they were compared among these groups. Results. Compared with the IR group, the treatment of QE reduced the release of cytokines, leading to inhibition of apoptosis and autophagy via downregulation of the ERK/NF-κB pathway in this model of hepatic IR injury. Conclusion. Apoptosis and autophagy caused by hepatic IR injury were inhibited by QE following a reduction in the release of inflammatory cytokines, and the relationship between the two may be associated with inactivation of the ERK/NF-κB pathway

    Clinical Study Metformin and Diammonium Glycyrrhizinate Enteric-Coated Capsule versus Metformin Alone versus Diammonium Glycyrrhizinate Enteric-Coated Capsule Alone in Patients with Nonalcoholic Fatty Liver Disease and Type 2 Diabetes Mellitus

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    Objective. The present study was conducted to compare the efficacy of metformin combined with diammonium glycyrrhizinate enteric-coated capsule (DGEC) versus metformin alone versus DGEC alone for the treatment of nonalcoholic fatty liver disease (NAFLD) in patients with type 2 diabetes mellitus (T2DM). Subjects and Methods. 163 patients with NAFLD and T2DM were enrolled in this 24-week study and were randomized to one of three groups: group 1 was treated with metformin alone; group 2 was treated with DGEC alone; group 3 received metformin plus DGEC combination therapy. Anthropometric parameters, liver function, lipid profile, serum ferritin (SF), metabolic parameters, liver/spleen computed tomography (CT) ratio, and fibroscan value were evaluated at baseline and after 8, 16, and 24 weeks of treatment. Results. After 24 weeks, significant improvements in all measured parameters were observed in three groups ( < 0.05) except for the improvements in low density lipoprotein cholesterol (LDL-C) and metabolic parameters in group 2 which did not reach statistical significance ( > 0.05). Compared with group 1 and group 2, the patients in group 3 had greater reductions in observed parameters apart from CB and TB ( < 0.05). Conclusions. This study showed that metformin plus DGEC was more effective than metformin alone or DGEC alone in reducing liver enzymes, lipid levels, and metabolic parameters and ameliorating the degree of hepatic fibrosis in patients with NAFLD and T2DM

    Diagnostic Performance of Des- γ

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    Background. There have been many reports on des-γ-carboxy prothrombin (DCP) as a promising serum marker in the diagnosis of hepatocellular carcinoma (HCC); however, the results are inconsistent and even conflicting. Methods. This meta-analysis was performed to investigate the performance of DCP in the diagnosis of HCC. Following a systematic review of relevant studies, Meta-DiSc 1.4 software was used to extract data and to calculate the overall sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR). Data are presented as forest plots and summary receiver operating characteristic curve (SROC) analysis was used to summarize the overall test performance. Results. Twelve studies were included in our meta-analysis. The overall sensitivity, specificity, PLR, and NLR of DCP for the detection of HCC in the studies included were 71% (95%CI: 68%–73%), 84% (95%CI: 83%–86%), 6.48 (95%CI: 4.22–9.93), and 0.33 (95%CI: 0.25–0.43), respectively. The area under the SROC curve was 0.8930 and the Q index was 0.8238. Significant heterogeneity was found. Conclusion. This meta-analysis indicated that DCP had moderate diagnostic accuracy in HCC. Further studies with rigorous design, large sample size, and mmultiregional cooperation are needed in the future

    Down-Regulation of MiR-127 Facilitates Hepatocyte Proliferation during Rat Liver Regeneration

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    Liver regeneration (LR) after partial hepatectomy (PH) involves the proliferation and apoptosis of hepatocytes, and microRNAs have been shown to post-transcriptionally regulate genes involved in the regulation of these processes. To explore the role of miR-127 during LR, the expression patterns of miR-127 and its related proteins were investigated. MiR-127 was introduced into a rat liver cell line to examine its effects on the potential target genes Bcl6 and Setd8, and functional studies were undertaken. We discovered that miR-127 was down-regulated and inversely correlated with the expression of Bcl6 and Setd8 at 24 hours after PH, a time at which hypermethylation of the promoter region of the miR-127 gene was detected. Furthermore, in BRL-3A rat liver cells, we observed that overexpression of miR-127 significantly suppressed cell growth and directly inhibited the expression of Bcl6 and Setd8. The results suggest that down-regulation of miR-127 may be due to the rapid methylation of its promoter during the first 24 h after PH, and this event facilitates hepatocyte proliferation by releasing Bcl6 and Setd8. These findings support a miRNA-mediated negative regulation pattern in LR and implicate an anti-proliferative role for miR-127 in liver cells
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