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.

Epidemiological characteristics and antimicrobial resistance of 151 cases of melioidosis in Hainan Province / 中国热带医学

@#Abstract: Objective　To analyze the epidemiological characteristics of 151 cases of melioidosis and the drug resistance of Burkholderia pseudomallei (BP), in order to provide the basis for diagnosis, treatment and reasonable prevention of melioidosis. Methods　A total of 151 inpatients and outpatients from the Second Affiliated Hospital of Hainan Medical University from January 1, 2013 to August 31, 2022 were collected, and clinical specimens were submitted for examination to isolate and identify BP strains. The clinical data of 151cases of melioidosis and the drug resistance characteristics of pathogenic bacteria were retrospectively analyzed, and using SPSS26.0 software for statistical analysis. Results　Among 151 cases with BP infection, there were 138 males (91.4%) and 13 females (8.6%); the most patients were aged from 45-<60 years old, accounting for 74 cases (49.0%); melioidosis incidence was concentrated in October (19.2%), November (19.2%), August (9.9%) and July (8.6%), and; the number of confirmed cases showed an increasing trend and the time for confirmation was <10 d; Internal medicine system (31.1%), surgery system (26.5%) and intensive care department (20.5%) were the common departments for treating melioidosis; blood (49.0%), sputum (9.9%) and wound secretion (8.6%) were the main clinical specimens for detecting BP; pulmonary infection (68.2%), sepsis (35.1%) and local suppurative infection (23.8%) were the top clinical manifestations in patients with BP infection; the effective rate of treating melioidosis was 74.8%; abnormal liver function was a risk factor for the curative effect of melioidosis (χ2=5.010, P<0.05); the sensitivity rates of BP strains to sulfamethoxazole-trimethoprim (SXT), doxycycline (DOX), imipenem(IPM), ceftazidime (CAZ), amoxicillin/clavulanate (AMC) and tetracycline (TCY) were generally more than 90%, with sensitivities of 98.7%, 97.2%, 96.7%, 94.0%, 93.2% and 90.7%, respectively. Conclusions　It can be concluded that misdiagnosis or missed diagnosis of melioidosis is easy to occur, and the understanding of the epidemiological characteristics and risk factors in this area should be strengthened. The sensitivity of BP to commonly used antibiotics has shown a certain downward trend, clinical use should be standardized, and drug resistance monitoring should be strengthened to improve the efficacy of melioidosis treatment.

Diagnostic value of cross-primer isothermal amplification technology in tuberculosis and its related influencing factors / 中国热带医学

@#Abstract： Objective　To analyze the value and influencing factors of cross-primer isothermal amplification technology(CPA) in clinical screening and diagnosis of tuberculosis (TB). Methods　We collected 543 inpatients in the Second Affiliated Hospital of Hainan Medical College from January 1, 2018 to December 31, 2021, including 179 patients with tuberculosis, 187 patients with pneumonia and 177 patients with other diseases. The patients' sputum, alveolar lavage fluid, pleural effusion and midstream urine were detected by CPA, smear microscopy, culture method and gene detection. The value of CPA detection in the diagnosis of tuberculosis and its influencing factors were evaluated. Statistical analysis was performed using SPSS 26.0. Results　The total positive rate of CPA was 14.4% (78/543), and the positive rate of sputum samples accounted for 29.1% (39/134). Among the 78 cases of CPA positive patients, the tuberculosis group accounted for 69.2% (54/78), followed by pneumonia group 21.8% (17/78), and other diseases group accounted for 9.0% (7/78). Taking CPA test as the reference method, the "sensitivity" of smear microscopy was lower than that of genetic testing and culture, while the "specificity" was higher than that of culture and gene testing, and the "missed diagnosis rate" of smear microscopy was higher than that of genetic testing and culture. CPA test positive was related to gender, ESR and pneumonia. There is a good agreement between CPA test and culture method and gene test (Kappa>0.9), and a moderate agreement between CPA test and smear microscopy (Kappa=0.616). Conclusions　Sputum specimen is the best choice for CPA detection, while the value of pleural effusion detection is relatively limited. Sputum, alveolar lavage fluid and midcourse urine can be used as clinical specimens for screening and diagnosis of "tuberculosis group and other disease group", while sputum can be used for screening and diagnosis of "tuberculosis group and pneumonia group". Gender, ESR and pneumonia are the influencing factors of CPA positive patients. Therefore, CPA testing is worthy of clinical promotion, but more clinical research data are needed.

[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.

Analysis of the etiological characteristics and drug resistance of adult patients with bloodstream infection in a hospital in Hainan, 2018-2020 / 中国热带医学

@#Abstract: Objective　To analyze the etiological characteristics and drug resistance of patients with bloodstream infection (BSI) in the bacterial resistance monitoring network in Hainan Province from 2018 to 2020, so as to provide laboratory data for clinical diagnosis and treatment. Methods　The clinical data of the subjects were collected, and the etiological characteristics of BSI patients and drug resistance of commonly used drugs in clinical treatment were analyzed retrospectively. SPSS 26.0 software was used for statistical analysis. Results　A total of 877 strains were isolated, including Gram-negative bacteria (584 strains, 66.6%), Gram-positive bacteria (239 strains, 27.2%) and fungi (54 strains, 6.2%); male patients (591 cases, 67.4%), female patients (286 cases, 32.6%); inpatients (780 cases, 88.9%), outpatient and emergency patients (97 cases, 11.1%); the main primary diseases of BSI patients were hypertension, cerebral infarction and type 2 diabetes, and the main primary infections were pulmonary infection and urinary system infection. Intensive care unit (25.2%, 221 cases), emergency department (10.9%, 96 cases), oncology department (9.1%, 80 cases), nephrology department (6.8%, 60 cases) and hepatobiliary and pancreatic surgery department (4.3%, 38 cases) had the highest proportion of pathogenic bacteria. Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, coagulase-negative Staphylococcus, Viridans group streptococci and Candida albicans were the most frequently isolated pathogens. The detection rates of carbapenem-resistant Klebsiella pneumoniae, carbapenem-resistant Pseudomonas aeruginosa and carbapenem-resistant Acinetobacter baumannii were 3.4%, 15.2% and 36.4% respectively. The carbapenem-resistant Escherichia coli was not checked out. The detection rates of methicillin resistant Staphylococcus aureus and methicillin resistant coagulase negative Staphylococcus were 18.5% and 79.1% respectively. Conclusions　Gram-negative bacteria are the most common pathogens of BSI, and inpatients are the main source of BSI. Age, underlying diseases and primary infection are the risk factors of BSI. Clinical laboratories should strengthen the etiological monitoring of high-risk patients with BSI, and the resistance analysis of common antibiotics can provide a basis for the rational use of antibiotics in clinical practice.

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.

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.

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.