5,034 research outputs found

    Two-orbital spin-fermion model study of ferromagnetism in honeycomb lattice

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    The spin-fermion model was previously successful to describe the complex phase diagrams of colossal magnetoresistive manganites and iron-based superconductors. In recent years, two-dimensional magnets have rapidly raised up as a new attractive branch of quantum materials, which are theoretically described based on classical spin models in most studies. Alternatively, here the two-orbital spin-fermion model is established as a uniform scenario to describe the ferromagnetism in a two-dimensional honeycomb lattice. This model connects the magnetic interactions with the electronic structures. Then the continuous tuning of magnetism in these honeycomb lattices can be predicted, based on a general phase diagram. The electron/hole doping, from the empty ege_{g} to half-filled ege_{g} limit, is studied as a benchmark. Our Monte Carlo result finds that the ferromagnetic TCT_{C} reaches the maximum at the quarter-filled case. In other regions, the linear relationship between TCT_{C} and doping concentration provides a theoretical guideline for the experimental modulations of two-dimensional ferromagnetism tuned by ionic liquid or electrical gating

    Establishment and assessments of a new model for the postoperative fatigue syndrome by major small intestinal resection in rats

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    Objective. Postoperative fatigue syndrome (POFS) is a general and main complication after surgery. However, there is no stable and standardized animal model for POFS. The aim of the present study was to establish a rodent model of POFS by small intestinal resection, with POFS evaluated by acknowledged physical and behavioral methods. Material and Methods. Forty-two Sprague-Dawley rats were randomly divided into four groups according to the length of a "middle" small intestinal resection: 0% (sham group; i.e., laparotomy alone), 10%, 40% and 70% groups, with corresponding lengths of small intestinal resections. Following surgery, the general state of health was evaluated. Tail suspension test, open field test and Morris water maze test were used to evaluate the degree of POFS. Serum albumin, transferrin, prealbumin and fibronectin were measured to assess the nutritional status, and superoxide dismutase (SOD) and malondialdehyde (MDA) were also measured. Results. As compared with the other three groups, the 70% small intestinal resection group showed the worst general state of health, decreased strength of the tail suspension test and decreased score of Morris water maze test (p < 0.05) after operation. All rats in whom the small intestinal resection was done demonstrated a certain degree of malnutrition and behavior of depression, and the 70% resection group had the lowest levels of transferrin, prealbumin and fibronectin as compared with the other groups (p < 0.05), as well as decreased SOD and increased MDA in serum (p < 0.05). Conclusions. Resection of 70% of the small intestine resulted in typical characteristics of POFS. As this procedure is simple, stable and easily reproducible, it may serve as a model for research on POFS

    Anti-Hepatitis B Virus X Protein in Sera Is One of the Markers of Development of Liver Cirrhosis and Liver Cancer Mediated by HBV

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    Hepatitis B virus X protein (HBx) plays a crucial role in the development of hepatocellular carcinoma (HCC). However, the significance of circulating antibody to hepatitis B virus X antigen (anti-HBx) in sera remains unclear. In the present study, we examined the titers of anti-HBx (IgG) in the sera from 173 patients with chronic hepatitis B (CHB), 106 liver cirrhosis (LC), and 61 HCC by enzyme-linked immunosorbent assay (ELISA), respectively. Our data showed that the positive rates of anti-HBx were higher in sera of LC (40.6%) and HCC (34.4%) than those of CHB (10.4%), P < .05. In all 40 patients with anti-HBx+ out of 340 patients, 39 (97.5%) were HBsAg/HBeAg/anti-HBc+ and 1 (2.5%) was anti-HBs+ (P < .01), suggesting that anti-HBx in sera is a marker of HBV replication rather than a protective antibody. Thus, our findings reveal that circulating anti-HBx in sera is one of the markers of development of LC and HCC mediated by HBV

    A Bayesian Network Method for Quantitative Evaluation of Defects in Multilayered Structures from Eddy Current NDT Signals

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    Accurate evaluation and characterization of defects in multilayered structures from eddy current nondestructive testing (NDT) signals are a difficult inverse problem. There is scope for improving the current methods used for solving the inverse problem by incorporating information of uncertainty in the inspection process. Here, we propose to evaluate defects quantitatively from eddy current NDT signals using Bayesian networks (BNs). BNs are a useful method in handling uncertainty in the inspection process, eventually leading to the more accurate results. The domain knowledge and the experimental data are used to generate the BN models. The models are applied to predict the signals corresponding to different defect characteristic parameters or to estimate defect characteristic parameters from eddy current signals in real time. Finally, the estimation results are analyzed. Compared to the least squares regression method, BNs are more robust with higher accuracy and have the advantage of being a bidirectional inferential mechanism. This approach allows results to be obtained in the form of full marginal conditional probability distributions, providing more information on the defect. The feasibility of BNs presented and discussed in this paper has been validated

    The association of serum uric acid with cognitive impairment and ATN biomarkers

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    BackgroundCognitive impairment (CI) has become a worldwide health problem. The relationship between CI and uric acid (UA) is contradictory.ObjectiveWe included participants with a full spectrum of CI, from cognitively unimpaired (CU) to dementia, from the Chongqing Ageing &amp; Dementia Study (CADS).MethodsFirst, we identified the relationships between serum UA (sUA) and cognitive function in different stages of CI. Second, we analyzed these relationships among different stages and types of CI. Finally, we explored the association between sUA and amyloid/tangle/neurodegeneration (ATN) biomarkers.ResultsWe recruited 427 participants from the CADS, including 382 participants with mini-mental state examination (MMSE) evaluation. The levels of sUA were positively correlated with MMSE scores (p &lt; 0.001), and the correlation was prominent in the course of dementia and in the type of Alzheimer’s disease (AD). The levels of UA had a positive correlation with plasma amyloid-β 42 (Aβ42) (p = 0.004). Higher levels of sUA weakened the correlation of MMSE scores with CSF ATN biomarkers and the correlation of CSF Aβ42 with tau.ConclusionUA is positively correlated with cognitive function, especially in the advanced stage of AD. The probable neuroprotective effects of sUA mainly act on Aβ42 and the downstream pathological cascade

    Monoester-Diterpene Aconitum

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    Aconitum, widely used to treat rheumatoid arthritis for thousands of years, is a toxic herb that can frequently cause fatal cardiac poisoning. Aconitum toxicity could be decreased by properly hydrolyzing diester-diterpene alkaloids into monoester-diterpene alkaloids. Monoester-diterpene alkaloids, including benzoylaconine (BAC), benzoylmesaconine (BMA), and benzoylhypaconine (BHA), are the primary active and toxic constituents of processed Aconitum. Cytochrome P450 (CYP) enzymes protect the human body by functioning as the defense line that limits the invasion of toxicants. Our purposes were to identify the CYP metabolites of BAC, BMA, and BHA in human liver microsomes and to distinguish which isozymes are responsible for their metabolism through the use of chemical inhibitors, monoclonal antibodies, and cDNA-expressed CYP enzyme. High-resolution mass spectrometry was used to characterize the metabolites. A total of 7, 8, and 9 metabolites were detected for BAC, BMA, and BHA, respectively. The main metabolic pathways were demethylation, dehydrogenation, demethylation-dehydrogenation, hydroxylation and didemethylation, which produced less toxic metabolites by decomposing the group responsible for the toxicity of the parent compound. Taken together, the results of the chemical inhibitors, monoclonal antibodies, and cDNA-expressed CYP enzymes experiments demonstrated that CYP3A4 and CYP3A5 have essential functions in the metabolism of BAC, BMA, and BHA
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