Comparative analysis of the gut microbiota of wild adult rats from nine district areas in Hainan, China.

BACKGROUND: Wild rats have the potential to hold zoonotic infectious agents that can spread to humans and cause disease. AIM: To better understand the composition of gut bacterial communities in rats is essential for preventing and treating such diseases. As a tropical island located in the south of China, Hainan province has abundant rat species. Here, we examined the gut bacterial composition in wild adult rats from Hainan province. METHODS: Fresh fecal samples were collected from 162 wild adult rats, including three species (Rattus norvegicus, Leopoldamys edwardsi, and Rattus losea), from nine regions of Hainan province between 2017-2018. RESULTS: We analyzed the composition of gut microbiota using the 16S rRNA gene amplicon sequencing. We identified 4903 bacterial operational taxonomic units (30 phyla, 175 families, and 498 genera), which vary between samples of different rat species in various habitats at various times of the year. In general, Firmicutes were the most abundant phyla, followed by Bacteroidetes (15.55%), Proteobacteria (6.13%), and Actinobacteria (4.02%). The genus Lactobacillus (20.08%), unidentified_Clostridiales (5.16%), Romboutsia (4.33%), unidentified_Ruminococcaceae (3.83%), Bacteroides (3.66%), Helicobacter (2.40%) and Streptococcus (2.37%) were dominant. CONCLUSION: The composition and abundance of the gut microbial communities varied between rat species and locations. This work provides fundamental information to identify microbial communities useful for disease control in Hainan province.

Quantum metric nonlinear Hall effect in a topological antiferromagnetic heterostructure.

Quantum geometry in condensed-matter physics has two components: the real part quantum metric and the imaginary part Berry curvature. Whereas the effects of Berry curvature have been observed through phenomena such as the quantum Hall effect in two-dimensional electron gases and the anomalous Hall effect (AHE) in ferromagnets, the quantum metric has rarely been explored. Here, we report a nonlinear Hall effect induced by the quantum metric dipole by interfacing even-layered MnBi2Te4 with black phosphorus. The quantum metric nonlinear Hall effect switches direction upon reversing the antiferromagnetic (AFM) spins and exhibits distinct scaling that is independent of the scattering time. Our results open the door to discovering quantum metric responses predicted theoretically and pave the way for applications that bridge nonlinear electronics with AFM spintronics.

[Effects of whole body vibration on bone strength and physical fitness in elderly COPD patients complicated with osteoporosis].

Objective: To investigate the effects of adding whole body vibration (WBV) to routine exercise regimen of pulmonary rehabilitation (PR) on bone strength, lung function and exercise ability of elderly patients with stable chronic obstructive pulmonary disease (COPD) complicated with osteoporosis (OP). Methods: Thirty seven elderly patients with stable COPD were randomly divided into control group (group C, n=12, age: 64.6±3.8 years), conventional PR group (PR group, n=12, age: 66.1±4.9 years), and whole body vibration combined PR group (WP group, n=13, age: 65.5±3.3 years). Before intervention, X-ray and computerized tomography bone scan, bone metabolic markers, pulmonary function, cardiopulmonary exercise, 6-minute walking and isokinetic muscle strength were performed, and then intervened for 36 weeks, three times/week, among which group C subjects were given routine treatment, PR group added aerobic running and static weight resistance on the basis of routine treatment, and WP group added WBV on the basis of PR group intervention. After the intervention, the same indicators were detected. Results: Compared with before the intervention, the pulmonary function indexes of each group were significantly improved after the intervention (P＜0.05), and the bone mineral density and bone microstructure indexes of the patients in the WP group were also significantly improved (P＜0.05). Compared with group C and group PR, the bone mineral density, bone microstructure, parathyroid hormone (PTH), insulin-like growth factor-1 (IGF-1), interleukin-6 (IL-6), osteocalcin (OCN) and other bone metabolism indexes, knee flexion, peak extension torque, fatigue index and muscle strength of patients in WP group were significantly improved (P＜0.05). Conclusion: Adding WBV to the conventional PR regimen can improve the bone strength, lung function and exercise capacity of elderly patients with COPD complicated with OP, and may be able to make up for the deficiency of the current conventional PR regimen for insufficient muscle and bone stimulation.

Monte Carlo evaluations of the absorbed dose and quality dependence of AL2O3 in radiotherapy photon beams.

PURPOSE: The purpose of this work was to evaluate the absorbed dose to AL2O3 dosimeter at various depths of water phantom in radiotherapy photon beams by Monte Carlo simulation and evaluate the beam quality dependence. METHODS: The simulations were done using EGSnrc. The cylindrical Al2O3 dosimeter (Phi4 mm x 1 mm) was placed at the central axis of the water phantom (Phi16 cm x 16 cm) at depths between 0.5 and 8 cm. The incident beams included monoenergetic photon beams ranging from 1 to 18 MeV, 60Co gamma beams, Varian 6 MV beams using phase space files based on a full simulation of the linac, and Varian beams between 4 and 24 MV using Mohan's spectra. The absorbed dose to the dosimeter and the water at the corresponding position in the absence of the dosimeter, as well as absorbed dose ratio factor fmd, was calculated. RESULTS: The results show that fmd depends obviously on the photon energy at the shallow depths. However, as the depth increases, the change in fmd becomes small, beyond the buildup region, the maximum discrepancy of fmd to the average value is not more than 1%. CONCLUSIONS: These simulation results confirm the use of Al2O3 dosimeter in radiotherapy photon beams and clearly indicate that more attention should be paid when using such a dosimeter in the buildup region of high-energy radiotherapy photon beams.

[Studies on fingerprints of Bupleurum chinense and vinegar-baked Bupleurum chinense from Hubei province].

OBJECTIVE: To establish the HPLC Fingerprint of Bupleurum chinense from GAP provenance of Hubei province Baokang, and discuss the changes before and after processing. METHODS: Using HPLC detection method equipped with Hypersil ODS column (5 microm, 4.6 mm x 250 mm), using acetonitrile-water as mobile phase gradient elution, flow as 1.0 ml/min, UV detector set at 203 nm, column temperature was at 25 degrees C. RESULTS: Similarity of processed Bupleurum chinense and Bupleurum chinense exceeded 0.95, and there were 13 characteristic fingerprints of processed Bupleurum chinense, 15 characteristic fingerprints of Bupleurum chinense. CONCLUSION: The HPLC Fingerprint of Bupleurum chinense from GAP provenance of Hubei province Baokang are established, and the difference between Bupleurum chinense before and after processing is studied initially.

[Study on the volatile oil by SFE-CO, from crude and processed Rhizoma Atractylodis by GC-MS].

OBJECTIVE: To analyze the chemical constituents of the volatile oil by SFE-CO2 from Rhizoma Atractylodis and its roasted products. METHODS: The chemical constituents of the volatile oil extracted by SFE-CO2 were separated and identified by GC-MS. RESULTS: 33 kinds of constituents were identified from Atractylodes lancea (Thunb.) DC. and its roasted products. The relative contents of 12 kinds of constituents from the processing products were descended and 7 kinds were ascended; 30 kinds of constituents were identified from Atractylodes chinensis (DC.) Koidz. and its roasted products. The relative contents of 10 kinds of constituents from the roasted products were descended and 11 kinds were ascended. CONCLUSION: In the processed products, the relative contents of some low boiling point constituents are descended but some high are ascended.

Faraday rotation echo spectroscopy and detection of quantum fluctuations.

Central spin decoherence is useful for detecting many-body physics in environments and moreover, the spin echo control can remove the effects of static thermal fluctuations so that the quantum fluctuations are revealed. The central spin decoherence approach, however, is feasible only in some special configurations and often requires uniform coupling between the central spin and individual spins in the baths, which are very challenging in experiments. Here, by making analogue between central spin decoherence and depolarization of photons, we propose a scheme of Faraday rotation echo spectroscopy (FRES) for studying quantum fluctuations in interacting spin systems. The echo control of the photon polarization is realized by flipping the polarization with a birefringence crystal. The FRES, similar to spin echo in magnetic resonance spectroscopy, can suppress the effects of the static magnetic fluctuations and therefore reveal dynamical magnetic fluctuations. We apply the scheme to a rare-earth compound LiHoF4 and calculate the echo signal, which is related to the quantum fluctuations of the system. We observe enhanced signals at the phase boundary. The FRES should be useful for studying quantum fluctuations in a broad range of spin systems, including cold atoms, quantum dots, solid-state impurities, and transparent magnetic materials.

Phase transitions in the complex plane of physical parameters.

At low temperature, a thermodynamic system undergoes a phase transition when a physical parameter passes through a singularity point of the free energy. This corresponds to the formation of a new order. At high temperature, thermal fluctuations destroy the order. Correspondingly, the free energy is a smooth function of the physical parameter and singularities only occur at complex values of the parameter. Since a complex valued parameter is unphysical, no phase transitions are expected when the physical parameter is varied. Here we show that the quantum evolution of a system, initially in thermal equilibrium and driven by a designed interaction, is equivalent to the partition function of a complex parameter. Therefore, we can access the complex singularity points of thermodynamic functions and observe phase transitions even at high temperature. We further show that such phase transitions in the complex plane are related to topological properties of the renormalization group flows of the complex parameters. This result makes it possible to study thermodynamics in the complex plane of physical parameters.