62 research outputs found

    Fluctuation Exchange Analysis of Superconductivity in the Standard Three-Band CuO2 Model

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    The fluctuation exchange, or FLEX, approximation for interacting electrons is applied to study instabilities in the standard three-band model for CuO2 layers in the high-temperature superconductors. Both intra-orbital and near-neigbor Coulomb interactions are retained. The filling dependence of the d(x2-y2) transition temperature is studied in both the "hole-doped" and "electron-doped" regimes using parameters derived from constrained-occupancy density-functional theory for La2CuO4. The agreement with experiment on the overdoped hole side of the phase diagram is remarkably good, i.e., transitions emerge in the 40 K range with no free parameters. In addition the importance of the "orbital antiferromagnetic," or flux phase, charge density channel is emphasized for an understanding of the underdoped regime.Comment: REVTex and PostScript, 31 pages, 26 figures; to appear in Phys. Rev. B (1998); only revised EPS figures 3, 4, 6a, 6b, 6c, 7 and 8 to correct disappearance of some labels due to technical problem

    Sensitivity of the Superconducting Transition Temperature to Changes in the Spin-Fluctuation Spectral Weight

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    In the simplest model of magnetic pairing, the transition temperature to the superconducting state depends on the dynamical susceptibility χ(q,ω)\chi({\bf q},\omega). We discuss how TcT_c is affected by different momentum and frequency parts of χ(q,ω)\chi({\bf q},\omega) for nearly antiferromagnetic and nearly ferromagnetic metals in two dimensions. While in the case of phonon-mediated superconductivity any addition of spectral weight to α2F(ω)\alpha^2F(\omega) at ω>0\omega >0 leads to an increase in TcT_c, we find that adding magnetic spectral weight at any momentum q{\bf q} and low frequencies ([0:3Tc][0:3T_c] and [0:(59)Tc][0:(5-9)T_c] for nearly antiferromagnetic and ferromagnetic metals respectively) leads to a suppression of TcT_c. The most effective frequency and momentum range consists of large momenta q(π,π){\bf q} \sim (\pi,\pi) and frequencies around 10Tc10T_c for nearly antiferromagnetic metals and small momenta q0{\bf q} \sim 0 and frequencies of approximately (1322)Tc(13-22)T_c for nearly ferromagnetic metals.Comment: 18 pages, 39 figure

    Quantum critical effects on transition temperature of magnetically mediated p-wave superconductivity

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    We determine the behavior of the critical temperature of magnetically mediated p-wave superconductivity near a ferromagnetic quantum critical point in three dimensions, distinguishing universal and non-universal aspects of the result. We find that the transition temperature is non-zero at the critical point, raising the possibility of superconductivity in the ferromagnetic phase.Comment: 4 pages, 4 figure

    The Effect of Thermal Reduction on the Photoluminescence and Electronic Structures of Graphene Oxides

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    [[abstract]]Electronic structures of graphene oxide (GO) and hydro-thermally reduced graphene oxides (rGOs)processed at low temperatures (120–1806C) were studied using X-ray absorption near-edge structure XANES), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS). C K-edge XANES spectra of rGOs reveal that thermal reduction restores C 5 C sp2 bonds and removes some of the oxygen and hydroxyl groups of GO, which initiates the evolution of carbonaceous species. The combination of C K-edge XANES and Ka XES spectra shows that the overlapping p and p* orbitals in rGOs and GO are similar to that of highly ordered pyrolytic graphite (HOPG), which has no band-gap. C Ka RIXS spectra provide evidence that thermal reduction changes the density of states (DOSs) that is generated in the p-region and/or in the gap between the p and p* levels of the GO and rGOs. Two-dimensional C Ka RIXS mapping of the heavy reduction of rGOs further confirms that the residual oxygen and/or oxygen-containing functional groups modify the p and s features, which are dispersed by the photon excitation energy. The dispersion behavior near the K point is approximately linear and differs from the parabolic-like dispersion observed in HOPG.[[notice]]補正完畢[[journaltype]]國外[[incitationindex]]SCI[[ispeerreviewed]]Y[[booktype]]電子版[[countrycodes]]GB

    Women with endometriosis have higher comorbidities: Analysis of domestic data in Taiwan

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    AbstractEndometriosis, defined by the presence of viable extrauterine endometrial glands and stroma, can grow or bleed cyclically, and possesses characteristics including a destructive, invasive, and metastatic nature. Since endometriosis may result in pelvic inflammation, adhesion, chronic pain, and infertility, and can progress to biologically malignant tumors, it is a long-term major health issue in women of reproductive age. In this review, we analyze the Taiwan domestic research addressing associations between endometriosis and other diseases. Concerning malignant tumors, we identified four studies on the links between endometriosis and ovarian cancer, one on breast cancer, two on endometrial cancer, one on colorectal cancer, and one on other malignancies, as well as one on associations between endometriosis and irritable bowel syndrome, one on links with migraine headache, three on links with pelvic inflammatory diseases, four on links with infertility, four on links with obesity, four on links with chronic liver disease, four on links with rheumatoid arthritis, four on links with chronic renal disease, five on links with diabetes mellitus, and five on links with cardiovascular diseases (hypertension, hyperlipidemia, etc.). The data available to date support that women with endometriosis might be at risk of some chronic illnesses and certain malignancies, although we consider the evidence for some comorbidities to be of low quality, for example, the association between colon cancer and adenomyosis/endometriosis. We still believe that the risk of comorbidity might be higher in women with endometriosis than that we supposed before. More research is needed to determine whether women with endometriosis are really at risk of these comorbidities

    Mortality prediction in patients with isolated moderate and severe traumatic brain injury using machine learning models.

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    BACKGROUND:The purpose of this study was to build a model of machine learning (ML) for the prediction of mortality in patients with isolated moderate and severe traumatic brain injury (TBI). METHODS:Hospitalized adult patients registered in the Trauma Registry System between January 2009 and December 2015 were enrolled in this study. Only patients with an Abbreviated Injury Scale (AIS) score ≥ 3 points related to head injuries were included in this study. A total of 1734 (1564 survival and 170 non-survival) and 325 (293 survival and 32 non-survival) patients were included in the training and test sets, respectively. RESULTS:Using demographics and injury characteristics, as well as patient laboratory data, predictive tools (e.g., logistic regression [LR], support vector machine [SVM], decision tree [DT], naive Bayes [NB], and artificial neural networks [ANN]) were used to determine the mortality of individual patients. The predictive performance was evaluated by accuracy, sensitivity, and specificity, as well as by area under the curve (AUC) measures of receiver operator characteristic curves. In the training set, all five ML models had a specificity of more than 90% and all ML models (except the NB) achieved an accuracy of more than 90%. Among them, the ANN had the highest sensitivity (80.59%) in mortality prediction. Regarding performance, the ANN had the highest AUC (0.968), followed by the LR (0.942), SVM (0.935), NB (0.908), and DT (0.872). In the test set, the ANN had the highest sensitivity (84.38%) in mortality prediction, followed by the SVM (65.63%), LR (59.38%), NB (59.38%), and DT (43.75%). CONCLUSIONS:The ANN model provided the best prediction of mortality for patients with isolated moderate and severe TBI

    Patterns Associated with Adult Mandibular Fractures in Southern Taiwan—A Cross-Sectional Retrospective Study

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    Purpose: This study aimed to determine the patterns associated with adult mandibular fractures from a Level-I trauma center in southern Taiwan. Methods: The data of adult trauma patients admitted between 1 January 2009 and 31 December 2014 were retrieved from the Trauma Registry System and retrospectively reviewed. Fracture site and cause of injury were categorized into groups for comparison, and corresponding odds ratios (ORs) and 95% confidence intervals (CIs) were obtained by multivariate logistic regression. Results: Motorcycle accidents were the most common cause of mandibular fractures (76.3%), followed by falls (10.9%), motor vehicle accidents (4.8%), and being struck by/against objects (4.5%). Of the 503 cases of mandibular fractures, the condylar neck and head were the most common sites (32.0%), followed by the parasymphysis (21.7%), symphysis (19.5%), angle and ramus (17.5%), and body (9.3%). The location of mandibular fractures in patients who had motorcycle accidents was similar to that in all patients. Motor vehicle accidents resulted in a significantly higher number of body fractures (OR 3.3, 95% CI 1.24–8.76, p = 0.017) and struck injury in a significantly higher number of angle and ramus fractures (OR 3.9, 95% CI 1.48–10.26, p = 0.006) compared to motorcycle accidents. The helmet-wearing status and body weight were not associated with the location of mandibular fractures in motorcycle accidents. Conclusions: Our study revealed that the anatomic fracture sites of mandible were specifically related to different etiologies. In southern Taiwan, motorcycle accidents accounted for the major cause of mandibular fractures and were associated with the condylar neck and head as the most frequent fracture sites. In contrast, motor vehicle accidents and struck injuries tended to cause more body fracture as well as angle and ramus fracture compared to motorcycle accidents. Furthermore, the status of helmet-wearing and body weight were not associated with the location of mandible fractures caused by motorcycle accidents

    Effect of Hypothermia in the Emergency Department on the Outcome of Trauma Patients: A Cross-Sectional Analysis

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    This study aimed to assess whether hypothermia is an independent predictor of mortality in trauma patients in the condition of defining hypothermia as body temperatures of <36 °C. Data of all hospitalized adult trauma patients recorded in the Trauma Registry System at a level I trauma center between 1 January 2009 and 12 December 2015 were retrospectively reviewed. A multivariate logistic regression analysis was performed in order to identify factors related to mortality. In addition, hypothermia and normothermia were defined as temperatures <36 °C and from 36 °C to 38 °C, respectively. Propensity score-matched study groups of hypothermia and normothermia patients in a 1:1 ratio were grouped for mortality assessment after adjusting for potential confounders such as age, sex, preexisting comorbidities, and injury severity score (ISS). Of 23,705 enrolled patients, a total of 401 hypothermic patients and 13,368 normothermic patients were included in this study. Only 3.0% of patients had hypothermia upon arrival at the emergency department (ED). Compared to normothermic patients, hypothermic patients had a significantly higher rate of abbreviated injury scale (AIS) scores of ≥3 in the head/neck, thorax, and abdomen and higher ISS. The mortality rate in hypothermic patients was significantly higher than that in normothermic patients (13.5% vs. 2.3%, odds ratio (OR): 6.6, 95% confidence interval (CI): 4.86–9.01, p < 0.001). Of the 399 well-balanced propensity score-matched pairs, there was no significant difference in mortality (13.0% vs. 9.3%, OR: 1.5, 95% CI: 0.94–2.29, p = 0.115). However, multivariate logistic regression analysis revealed that patients with low body temperature were significantly associated with the mortality outcome. This study revealed that low body temperature is associated with the mortality outcome in the multivariate logistic regression analysis but not in the propensity score matching (PSM) model that compared patients with hypothermia defined as body temperatures of <36 °C to those who had normothermia. These contradicting observations indicated the limitation of the traditional definition of body temperature for the diagnosis of hypothermia. Prospective randomized control trials are needed to determine the relationship between hypothermia following trauma and the clinical outcome

    Comparison of the new Exponential Injury Severity Score with the Injury Severity Score and the New Injury Severity Score in trauma patients: A cross-sectional study.

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    To compare Exponential Injury Severity Score (EISS) with Injury Severity Score (ISS) and New Injury Severity Score (NISS) in terms of their predictive capability of the outcomes and medical expenses of hospitalized adult trauma patients.This study was based at a level I trauma center in Taiwan.Data for 17,855 adult patients hospitalized from January 1, 2009 to December 31, 2015 were retrieved from the Trauma Registry System. The primary outcome was in-hospital mortality. Secondary outcomes were the hospital length of stay (LOS), intensive care unit (ICU) admission rate, ICU LOS, and medical expenses. Chi-square tests were used for categorical variables to determine the significance of the associations between the predictor and outcome variables. Student t-tests were applied to analyze normally distributed data for continuous variables, while Mann-Whitney U tests were used to compare non-normally distributed data.According to the survival rate-to-severity score relationship curve, we grouped all adult trauma patients based on EISS scores of ≥ 27, 9-26, and < 9. Significantly higher mortality rates were noted in patients with EISS ≥ 27 and those with EISS of 9-26 when compared to patients with EISS < 9; this finding concurred to the findings for groups classified by the ISS and NISS with the cut-off points set between 25 and 16. The hospital LOS, ICU admission rates, and medical expenses for patients with EISS ≥ 27 and patients with EISS of 9-26 were also significantly longer and higher than that of patients with EISS < 9. When comparing the demographics and detailed medical expenses of very severely injured adult trauma patients classified according to ISS, NISS, and EISS, patients with ISS ≥ 25 and NISS ≥ 25 both had significantly lower mortality rates, lower ICU admission rates, and shorter ICU LOS compared to patients with EISS ≥ 27.EISS 9 and 27 can serve as two cut-off points regarding injury severity, and patients with EISS ≥ 27 have the greatest injury severity. Additionally, these patients have the highest mortality rate, the highest ICU admission rate, and the longest ICU LOS compared to those with ISS ≥ 25 and NISS ≥ 25, suggesting that patients with EISS ≥ 27 have the worst outcome
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