Identification of Magnetic Interactions and High-field Quantum Spin Liquid in α\alpha-RuCl3_3

The frustrated magnet $\alpha$-RuCl$_3$ constitutes a fascinating quantum material platform that harbors the intriguing Kitaev physics. However, a consensus on its intricate spin interactions and field-induced quantum phases has not been reached yet. Here we exploit multiple state-of-the-art many-body methods and determine the microscopic spin model that quantitatively explains major observations in $\alpha$-RuCl$_3$, including the zigzag order, double-peak specific heat, magnetic anisotropy, and the characteristic M-star dynamical spin structure, etc. According to our model simulations, the in-plane field drives the system into the polarized phase at about 7 T and a thermal fractionalization occurs at finite temperature, reconciling observations in different experiments. Under out-of-plane fields, the zigzag order is suppressed at 35 T, above which, and below a polarization field of 100 T level, there emerges a field-induced quantum spin liquid. The fractional entropy and algebraic low-temperature specific heat unveil the nature of a gapless spin liquid, which can be explored in high-field measurements on $\alpha$-RuCl$_3$.Comment: To appear in Nature Communications (12 pages, 6 figures, and 5 Supplementary Notes

Preparation of a nano emodin transfersome and study on its anti-obesity mechanism in adipose tissue of diet-induced obese rats

OBJECTIVE: To describe the preparation of nano emodin transfersome (NET) and investigate its effect on mRNA expression of adipose triglyceride lipase (ATGL) and G0/G1 switch gene 2 (G0S2) in adipose tissue of diet-induced obese rats. METHODS: NET was prepared by film-ultrasonic dispersion method. The effects of emodin components at different ratios on encapsulation efficiency were investigated.The NET envelopment rate was determined by ultraviolet spectrophotometry. The particle size and Zeta potential of NET were evaluated by Zetasizer analyzer. Sixty male SD rats were assigned to groups randomly. After 8-week treatment, body weight, wet weight of visceral fat and the percentage of body fat (PBF) were measured. Fasting blood glucose and serum lipid levels were determined. The adipose tissue section was HE stained, and the cellular diameter and quantity of adipocytes were evaluated by light microscopy. The mRNA expression of ATGL and G0S2 from the peri-renal fat tissue was assayed by RT-PCR. RESULTS: The appropriate formulation was deoxycholic acid sodium salt vs. phospholipids 1:8, cholesterol vs. phospholipids 1:3, vitamin Evs. phospholipids 1:20, and emodin vs. phospholipid 1:6. Zeta potential was −15.11 mV, and the particle size was 292.2 nm. The mean encapsulation efficiency was (69.35 ± 0.25)%. Compared with the obese model group, body weight, wet weight of visceral fat, PBF and mRNA expression of G0S2 from peri-renal fat tissue were decreased significantly after NET treatment (all P < 0.05), while high-density lipoprotein cholesterol (HDL-C), the diameter of adipocytes and mRNA expression of ATGL from peri-renal fat tissue were increased significantly (all P < 0.05). CONCLUSION: The preparation method is simple and reasonable. NET with negative electricity was small and uniform in particle size, with high encapsulation efficiency and stability. NET could reduce body weight and adipocyte size, and this effect was associated with the up-regulation of ATGL, down-regulation of G0S2 expression in the adipose tissue, and improved insulin sensitivity

Levothyroxine Exhibits Inhibitory Effect towards UDP-Glucuronosyltransferase (UGT) 1A6-Mediated 4-Methylumbelliferone (4-MU) Glucuronidation

Levothyroxine, a synthetic form of thyroid hormone, has been clinically used to treat thyroid hormone deficiency. UDP-glucuronosyltransferases (UGTs) are important phase II drug-metabolizing enzymes, and UGTs-inhibition based drug-drug interaction has been widely reported. The aim of the present study is to investigate the inhibitory effect of levothyroxine towards UGT1A6-catalyzed 4-methylumbelliferone (4-MU) glucuronidation. The results showed that levothyroxine inhibited UGT1A6-catalyzed 4-MU glucuronidation reaction in a dose-dependent manner. Furthermore, Lineweaver-Burk and Dixon plots showed the inhibition of UGT1A6 by levothyroxine was best fit to competitive inhibition, and the inhibition kinetic parameter (Ki ) was determined to be 15.3 μM. Given that UGT1A6 is one of the most important UGT isoforms catalyzing the glucuronidation reaction of many important clinical drugs, including aspirin and serotonin, inhibition of UGT1A6 activity by levothyroxine will significantly influence the pharmacokinetic behaviour of these drugs. Therefore, clinical drug-drug interaction due to the inhibition of UGT1A6 by levothyroxine should paid much attention.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Three-level Back-to-Back Converter Simulation for Wind Turbine Energy Source

AbstractThis paper presents the simulation of three-level back-to-back converter for wind turbine energy source. For this paper, it will be focused on wind turbine energy source and determined the voltage from wind turbine energy source being regular value. The operation of the converter can be simulated by using MATLAB/SIMULINK program. Moreover, the voltage and current of the converter can be properly controlled by SVPWM. The simulation results shown that the output current waveform have signal distortion less than the input current waveform, and also the output voltage waveform is more than the input as well. Therefore, this converter can convert the voltage and current from the AC to DC and from the DC to AC for more performance, and it can be connected to the grid

Human bocavirus 1 is a genuine pathogen for acute respiratory tract infection in pediatric patients determined by nucleic acid, antigen, and serology tests

BackgroundHuman bocavirus 1 (HBoV1), first discovered in 2005, was positive in symptomatic and healthy children and co-detected with other respiratory viruses. It is a long journey to decisively demonstrate the unique viral pathogenic function of acute respiratory tract infection (ARTI) in pediatric patients.MethodsRespiratory specimens collected from pediatric patients with ARTI from January 2017 to December 2021 were screened by a capillary electrophoresis-based multiplex PCR (CEMP) assay, then genotyped by PCR and sequencing for HBoV1. For the antigen test, a part of HBoV1 DNA positive nasopharyngeal aspirates (NPAs) was used as an antigen, while a rabbit anti-HBoV1 DR2 specific to HBoV1 was used as an antibody in the indirect-immunofluorescence assay (IFA). Finally, the levels of IgG specific to HBoV1 in acute and convalescent sera selected retrospectively from only HBoV1 DNA-positive patients were evaluated by IFA.ResultsAmong 9,899 specimens, 681 were positive for HBoV1 DNA (6.88%, 681/9899), which included 336 positives only for HBoV1 (49.34%, 336/681) and 345 (50.66%, 345/681) positives also for other pathogens. In the antigen test, there were 37 among 47 NPAs determined as HBoV1 antigen-positive (78.72%, 37/47), including 18 (48.65%, 18/37) positives solely for HBoV1 DNA. Among 4 pediatric patients with both acute and convalescent sera, there was one positive for HBoV1 antigen (D8873) and 2 lack the antigen results (D1474 and D10792), which showed seroconversion with a ≥ 4-fold increase in IgG levels.ConclusionsThe combination results of nucleic acid, antigen, and serology tests answered that HBoV1 is a genuine pathogen for ARTI in pediatric patients

Disc-corona interaction in the heartbeat state of GRS 1915+105

Timing analysis provides information about the dynamics of matter accreting on to neutron stars and black holes, and hence is crucial for studying the physics of the accretion flow around these objects. It is difficult, however, to associate the different variability components with each of the spectral components of the accretion flow. We apply several new methods to two Rossi X-ray Timing Explorer observations of the black hole binary GRS 1915+105 during its heartbeat state to explore the origin of the X-ray variability and the interactions of the accretion-flow components. We offer a promising window into the disc--corona interaction through analysing the formation regions of the disc aperiodic variabilities with different time-scales via comparing the corresponding transition energies of the amplitude-ratio spectra. In a previous paper, we analysed the Fourier power density as a function of energy and frequency to study the origin of the aperiodic variability, and combined that analysis with the phase lag as a function of frequency to derive a picture of the disc--corona interaction in this source. We here, for the first time, investigate the phase lag as a function of energy and frequency, and display some interesting details of the disc--corona interaction. Besides, the results from the shape of amplitude-ratio spectrum and from several other aspects suggest that the quasi-periodic oscillation originates from the corona.Comment: 12 pages, 7 figure