2,407 research outputs found
Holographic conductivity from Einstein-Maxwell-Dilaton in Gauss-Bonnet gravity and Entropy Function
In this paper we consider the holographic DC and Hall conductivity in
Einstein-Maxwell-Dilaton in Gauss-Bonnet gravity with momentum dissipation. We
analytically derived the DC conductivity and Hall conductivity from the black
horizon data, and found that the conductivities are independent on the
Gauss-Bonnet coupling. We also used the entropy function formalism to get the
conductivities in terms of the charge of the black hole, even without knowing
the explicit black hole solutions.Comment: 15 page
Numerical Simulation and Experimental Study on the Gas-Solid Coupling of the Aerostatic Thrust Bearing with Elastic Equalizing Pressure Groove
Aiming at the problem of low stiffness of aerostatic bearing, according to the principle of gas-solid coupling, this paper designs a kind of aerostatic thrust bearing with elastic equalizing pressure groove (EEPG) and investigates the effect of elastic equalizing pressure groove (EEPG) on the stiffness of aerostatic bearing. According to the physical model of the bearing, one deduces the deformation control equation of the elastic equalizing pressure groove and the control equation of gas lubrication, using finite difference method to derive the control equations and coupling calculation. The bearing capacity and stiffness of aerostatic bearing with EEPG in different gas film clearance are obtained. The calculation results show that the stiffness increased by 59%. The results of numerical calculation and experimental results have good consistency, proving the gas-solid coupling method can improve the bearing stiffness
The Management of Heavy Menstrual Bleeding After Percutaneous Coronary Intervention in a Woman of Reproductive Age
Heavy menstrual bleeding (HMB), previously known as menorrhagia, is in place with heavy flow and longer lasting days of bleeding during menstrual period, sequentially leading to anemia. We reported a rare case of HMB in a 33-year-old patient after percutaneous coronary intervention (PCI), who presented with acute coronary syndromes (ACS), uremia and systemic lupus erythematosus before PCI. This patient received three times of hemodialysis weekly (Monday, Wednesday, and Friday). On the next day after PCI, this patient began to have menstruation. On the fifth day of menstruation, the patient complained of HMB and physical discomfort, with an urgent need for consultation of gynecologist. After gynecologist consultation, this patient was under oxytocin treatment. However, 2 days of oxytocin treatment did not significantly improve HMB. Afterward, the menstrual volume of patients was significantly reduced on eighth day of menstruation after once therapy of testosterone propionate and norethindrone. Regarding the reasons of HMB, heparin in hemodialysis and antiplatelet drugs utilized (aspirin and clopidogrel) after PCI may be contributors to the HMB. In addition, uterine myoma, cervical canal cyst, renal insufficiency and CYP2C19∗2 heterozygous are also possible contributors to HMB. There is no such case of whom had HMB in reproductive age with ACS, uremia and systemic lupus erythematosus under hemodialysis and antiplatelet therapy. More clinical safety data on HMB of reproductive age women who are under antithrombotic therapy are required
Neuroprotective Effect of Gui Zhi ( Ramulus Cinnamomi
Herb Ephedra (Ma Huang in Chinese) and Ramulus Cinnamomi (Gui Zhi in Chinese) are traditional Chinese herbs, often used together to treat asthma, nose and lung congestion, and fever with anhidrosis. Due to the adverse effects of ephedrine, clinical use of Ma Huang is restricted. However, Gui Zhi extract has been reported to decrease spontaneous activity in rats and exert anti-inflammatory and neuroprotective effects. The present study explored the possible inhibitory effect of Gui Zhi on Ma Huang-induced neurotoxicity in rats when the two herbs were used in combination. All Ma Huang and Ma Huang-Gui Zhi herb pair extracts were prepared using methods of traditional Chinese medicine and were normalized based on the ephedrine content. Two-month-old male Sprague-Dawley rats (n=6 rats/group) were administered Ma Huang or the Ma Huang-Gui Zhi herb pair extracts for 7 days (ephedrine = 48 mg/kg), and locomotor activity was measured. After 7 days, oxidative damage in the prefrontal cortex was measured. Gui Zhi decreased hyperactivity and sensitization produced by repeated Ma Huang administration and attenuated oxidative stress induced by Ma Huang. The results of this study demonstrate the neuroprotective potential of Gui Zhi in Ma Huang-induced hyperactivity and oxidative damage in the prefrontal cortex of rats when used in combination
Controllable synthesis of flake-like Al-doped ZnO nanostructures and its application in inverted organic solar cells
Flake-like Al-doped ZnO (AZO) nanostructures including dense AZO nanorods were obtained via a low-temperature (100°C) hydrothermal process. By doping and varying Al concentrations, the electrical conductivity (σ) and morphology of the AZO nanostructures can be readily controlled. The effect of σ and morphology of the AZO nanostructures on the performance of the inverted organic solar cells (IOSCs) was studied. It presents that the optimized power conversion efficiency of the AZO-based IOSCs is improved by approximately 58.7% compared with that of un-doped ZnO-based IOSCs. This is attributed to that the flake-like AZO nanostructures of high σ and tunable morphology not only provide a high-conduction pathway to facilitate electron transport but also lead to a large interfacial area for exciton dissociation and charge collection by electrodes
Epithelial Heat Shock Proteins Mediate the Protective Effects of Limosilactobacillus reuteri in Dextran Sulfate Sodium-Induced Colitis
Defects in gut barrier function are implicated in gastrointestinal (GI) disorders like inflammatory bowel disease (IBD), as well as in systemic inflammation. With the increasing incidence of IBD worldwide, more attention should be paid to dietary interventions and therapeutics with the potential to boost the natural defense mechanisms of gut epithelial cells. The current study aimed to investigate the protective effects of Limosilactobacillus reuteri ATCC PTA 4659 in a colitis mouse model and delineate the mechanisms behind it. Wild-type mice were allocated to the control group; or given 3% dextran sulfate sodium (DSS) in drinking water for 7 days to induce colitis; or administered L. reuteri for 7 days as pretreatment; or for 14 days starting 7 days before subjecting to the DSS. Peroral treatment with L. reuteri improved colitis severity clinically and morphologically and reduced the colonic levels of Tumor necrosis factor-alpha (TNF-alpha) (Tnf), Interleukin 1-beta (Il1 beta), and nterferon-gamma (Ifng), the crucial pro-inflammatory cytokines in colitis onset. It also prevented the CD11b(+)Ly6G(+) neutrophil recruitment and the skewed immune responses in mesenteric lymph nodes (MLNs) of CD11b(+)CD11c(+) dendritic cell (DC) expansion and Foxp3(+)CD4(+) T-cell reduction. Using 16S rRNA gene amplicon sequencing and RT-qPCR, we demonstrated a colitis-driven bacterial translocation to MLNs and gut microbiota dysbiosis that were in part counterbalanced by L. reuteri treatment. Moreover, the expression of barrier-preserving tight junction (TJ) proteins and cytoprotective heat shock protein (HSP) 70 and HSP25 was reduced by colitis but boosted by L. reuteri treatment. A shift in expression pattern was also observed with HSP70 in response to the pretreatment and with HSP25 in response to L. reuteri-DSS. In addition, the changes of HSPs were found to be correlated to bacterial load and epithelial cell proliferation. In conclusion, our results demonstrate that the human-derived L. reuteri strain 4659 confers protection in experimental colitis in young mice, while intestinal HSPs may mediate the probiotic effects by providing a supportive protein-protein network for the epithelium in health and colitis
Tacrolimus (Tacro) strongly inhibits intestinal UDP-glucuronosyltransferase (UGT) 1A8
Tacrolimus (Brand name: Prograf), a kind of immunosuppressants, has been reported to induce drug-drug interaction with many clinical drugs. Tacrolimus-mycophenolic acid (MPA) interaction has been widely and frequently reported. Intestinal UDP-glucuronosyltransferase (UGT) 1A8-mediated metabolism plays a key role in the elimination of MPA, and alteration of the activity of UGT1A8 resulting from gene polymorphisms could significantly influence the catalyzing activity of MPA glucuronidation. The aim of the present study is to investigate the inhibitory potential of tacrolimus towards UGT1A8, which was speculated to be a potential cause for tacrolimus-MPA interaction. The recombinant UGT1A8 was used as enzyme source, and a nonspecific substrate 4-methylumbelliferone (4-MU) was utilized as substrate. The results showed that 100 μM of tacrolimus inhibited UGT1A8-mediated 4-MU glucuronidation activity by 82.3%. Further inhibition kinetic investigation showed that the inhibition of UGT1A8 by tacrolimus was best fit to competitive inhibition type, and the inhibition kinetic parameter (Ki) was determined to be 6.1 μM. All these results indicated that tacrolimus could exhibit strong inhibition towards UGT1A8, which should be paid more attention when explaining clinical tacrolimus-MPA interaction.Colegio de Farmacéuticos de la Provincia de Buenos Aire
LAMOST medium-resolution spectroscopic survey of binarity and exotic star (LAMOST-MRS-B): Observation strategy and target selection
LAMOST-MRS-B is one of the sub-surveys of LAMOST medium-resolution (R~7500)
spectroscopic survey. It aims at studying the statistical properties (e.g.,
binary fraction, orbital period distribution, mass ratio distribution) of
binary stars and exotic stars. We intend to observe about 30000 stars (10 mag
<= G <= 14.5 mag) with at least 10 visits in five years. We first planned to
observe 25 plates around the galactic plane in 2018. Then the plates were
reduced to 12 in 2019 because of the limitation of observation. At the same
time, two new plates located at the high galactic latitude were added to
explore binary properties influenced by the different environments. In this
survey project, we set the identified exotic and low-metallicity stars with the
highest observation priorities. For the rest of the selected stars, we gave
higher priority to the relatively brighter stars in order to obtain
high-quality spectra as many as possible. Spectra of 49129 stars have been
obtained in LAMOST-MRS-B field and released in DR8, of which 28828 and 3375
stars have been visited more than twice and ten times with SNR >= 10,
respectively. Most of the sources are B-, A-, and F-type stars with 0.6 <
[Fe/H] < 0.4 dex. We also obtain 347 identified variable and exotic stars and
about 250 stars with [Fe/H] < 1 dex. We measure radial velocities (RVs) by
using 892233 spectra of the stars. The uncertainties of RV achieve about 1 km/s
and 10 km/s1 for 95% of late- and early-type stars, respectively. The datasets
presented in this paper are available at
http://www.doi.org/10.57760/sciencedb.j00113.00035
Risk factors associated with postoperative respiratory failure after esophagectomy for esophageal cancer
Aim: Respiratory failure is common after esophagectomy for esophageal cancer (EC). This study aimed to identify the risk factors associated with postoperative respiratory failure following esophagectomy for EC. Methods: A single-center observational study from China was conducted on 262 patients with EC who underwent thoracoscopic esophagectomy between April 2014 and June 2016. The patients were divided into two groups: group I (respiratory failure) and group II (without respiratory failure). Demographic and perioperative variables, tumor-related factors, surgical factors, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, and clinical course were compared between the groups. Univariable and multivariable logistic regression analyses were performed to assess the risk factors of postoperative respiratory failure after esophagectomy. Results: Among the 262 patients, 24 (9.2%) developed respiratory failure. Univariable analysis revealed several risk factors, including age, smoking, comorbidities, partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2), forced vital capacity (FVC), FVC percentage (FVC%), urine volume during surgery, and APACHE II score. Multivariable analysis showed that age, comorbidities of diabetes mellitus (DM), FVC%, urine volume during surgery, and APACHE II score were independent predictors of respiratory failure. Specifically, elderly patients (> 65 years) with comorbidities of DM, lower FVC%, higher urine volume during surgery, and elevated APACHE II score were found to be more susceptible to respiratory failure, resulting in prolonged hospitalization and increased healthcare burden. These findings emphasize the importance of considering these factors in the management and care of patients at risk of respiratory failure. Conclusions: As a common complication following esophagectomy for EC. Respiratory failure is significantly associated with age, comorbidities of DM, FVC%, urine volume during surgery, and APACHE II score in the dataset. The findings will contribute to the evaluation of the risk of respiratory failure and guide early intervention strategies in clinical decision-making
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