Raman scattering study of multimagnon (bi- and tri-magnon) excitations and rotonlike points in the distorted triangular lattice antiferromagnet

We investigate the experimental signatures of Raman spectroscopy of bi- and tri-magnon excitations in the distorted triangular lattice antiferromagnets alpha-LCr2O4 (L=Sr, Ca). We utilize spin wave theory to analyze the nearly 120 degree spin-3/2 spiral ordered antiferromagnetic ground state to compute the single-magnon density of states, single-magnon dispersion, and bimagnon and trimagnon Raman spectra (polarized and unpolarized). It is found that Raman scattering is capable of capturing the effect of the rotonlike M and M' points on the bimagnon Raman spectrum. Our calculation confirms the connection between single-magnon rotonlike excitation energy and bimagnon Raman excitation spectrum observed experimentally. The roton energy minimum in momentum space is half of the energy of a bimagnon excitation signal. The experimental magnetic Raman scattering result displays two peaks which have a Raman shift of 15 meV and 40 meV, respectively. Theoretical modeling and analysis of the experimental spectrum of alpha-SrCr2O4 within our distorted Heisenberg Hamiltonian lattice suggests that the low-energy peak at 15 meV is associated with the bimagnon excitation, whereas the high-energy peak around 40 meV is primarily a trimagnon excitation. Based on our fitting procedure we propose a new set of magnetic interaction parameters for alpha-SrCr2O4. These parameters reproduce not only the experimental Raman spectrum, but also the inelastic neutron scattering response (including capturing high energy magnon branches). We also compute the unpolarized bimagnon and trimagnon Raman spectra for alpha-CaCr2O4. Furhtermore, we found that the polarization sensitivity of Raman spectrum can be utilized to distinguish the bi- and tri-magnon excitation channels.Comment: 11 pages, 4 figure

Clinical efficacy of a combination of propofol and etomidate in pediatric anesthesia, and its effect on vital indices in patients

Purpose: To study the clinical effectiveness of a combination of propofol and etomidate as pediatricanesthesia, and its influence on some vital factors in the patients.Methods: A total of 104 children who underwent appendectomy, hepatobiliary surgery and excision ofbone tumor in Xuzhou Children's Hospital, Xuzhou Medical University, Xuzhou, China from June 2018 to June 2020, were selected for this retrospective study. The patients were divided into groups A, B and C. In group A, 40 patients received the combination of propofol and etomidate, 32 patients received propofol only, while group C comprised 32 patients who received etomidate only. Vital indices such asanesthesia induction time, wake-up time after surgery, anesthetic effect, and adverse reactions were determined.Results: In group A, the mean arterial pressure (MAP) and heart rate (HR) were improved; anesthesia induction time and wake-up time after surgery were shorter, and anesthetic effect was more obvious in children with grades I and II. However, there was no grade III anesthetic effect, although there was a lower incidence of adverse reactions in this group.Conclusion: The use of a combination of propofol and etomidate results in higher clinical efficacy of pediatric anesthesia than either propofol or etomidate alone. Furthermore, the combination produces better quality of vital indices in the patient

Clinical efficacy of a combination of propofol and etomidate in pediatric anesthesia, and its effect on vital indices in patients

Purpose: To study the clinical effectiveness of a combination of propofol and etomidate as pediatric anesthesia, and its influence on some vital factors in the patients.Methods: A total of 104 children who underwent appendectomy, hepatobiliary surgery and excision of bone tumor in Xuzhou Children's Hospital, Xuzhou Medical University, Xuzhou, China from June 2018 to June 2020, were selected for this retrospective study. The patients were divided into groups A, B and C. In group A, 40 patients received the combination of propofol and etomidate, 32 patients received propofol only, while group C comprised 32 patients who received etomidate only. Vital indices such as anesthesia induction time, wake-up time after surgery, anesthetic effect, and adverse reactions were determined.Results: In group A, the mean arterial pressure (MAP) and heart rate (HR) were improved; anesthesia induction time and wake-up time after surgery were shorter, and anesthetic effect was more obvious in children with grades I and II. However, there was no grade III anesthetic effect, although there was a lower incidence of adverse reactions in this group.Conclusion: The use of a combination of propofol and etomidate results in higher clinical efficacy of pediatric anesthesia than either propofol or etomidate alone. Furthermore, the combination produces better quality of vital indices in the patients

Evaporative Enrichment of Oxygen-18 and Deuterium in Lake Waters on the Tibetan Plateau

Stable isotopes (δ18O and δD) are useful tracers for investigating hydrologic and climatic variability on a variety of temporal and spatial scales. Since the early isotopic studies on mountainous glaciers in the late 1960s, a great deal of information has been generated on the isotopic composition of rainfall, snow, ice, surface waters, and lake carbonate sediments across the Tibetan Plateau. However, measurements of δ18O and δD values of lake water are scarce. Here we present a new dataset of δ18O and δD values of lake waters collected from 27 lakes across the plateau during a reconnaissance survey in summer 2009. δ18O and δD values of lake water range from −19.9 to 6.6‰ and from −153 to −16‰, respectively. The average values of δ18O and δD are −6.4 and −72‰, considerably greater than those of precipitation observed in this region. The derived Tibetan lake water line, δD = 5.2δ18O − 38.9, is significantly different from the global meteoric water line. Most of the lakes, including some freshwater lakes, contain water with negative values of d-excess (d). There is a negative correlation between d and total dissolved solids (TDS). Each of these findings indicates that evaporation-induced isotopic enrichment prevails in Tibetan lakes. Moreover, we develop an isotope modeling scheme to calculate E/P ratios for Tibetan lakes, using a combination of existing isotopic fractionation equations and the Rayleigh distillation model. We use the intersection of the local evaporation line and GMWL as a first approximation of δ18O and δD values of lake water inputs to infer an E/P ratio for each lake. Our modeling calculations reveal that although variable from lake to lake, the water budget across the plateau is positive, with an average E/P of 0.52. This is in good agreement with other observational and model data that show varying degrees of increases in lake size from satellite imagery and significant decreases in lake salinity in many lakes on the plateau over the last several decades. Together with the new isotopic dataset, the proposed modeling framework can be used to examine and quantify past changes in a lake’s hydrologic balance from the isotopic record of downcore carbonate sediments in the region

Correlation between Internet Addiction Disorder and Mental Health of Junior Middle School Students in Chengdu

Objective: To study the prevalence and main influencing factors of Internet addiction among junior middle school students in Chengdu, and to provide scientific basis for the prevention and intervention of Internet addiction. Methods: From September to December 2017, 3,607 junior middle school students were randomly selected from 8 middle schools in Chengdu by stratified cluster sampling, and investigated by selfmade questionnaire. SPSS 19.0 software was used for χ 2 test and multiple linear regression analysis. Results: 174 of 3,607 junior middle school students in Chengdu were diagnosed with Internet addiction, and the detection rate of Internet addiction was 4.8%. There were significant differences in the scores of mental health, learning pressure, parent-child relationship and peer relationship between Internet addiction and non-internet addiction junior middle school students (P < 0.05). The results of multiple linear regression showed that family economic status, learning pressure, depression and anxiety were positively correlated with internet addiction, while parent-child relationship, peer relationship and social support were negatively correlated with Internet addiction (P < 0.05, P < 0.01). Conclusion: The detection rate of Internet addiction among junior middle school students in Chengdu is at a low level. Junior middle school students with low social support and high depression and anxiety have a higher risk of Internet addiction, which can be reduced by improving their mental health

Periodicity staircase in a Fe/Gd magnetic thin film

Presence of multiple competing periodicities may result in a system to go through states with modulated periodicities, an example of which is the self-similar staircase-like structure called the Devil's staircase. Herein we report on a novel staircase structure of domain periodicity in an amorphous and achiral Fe/Gd magnetic thin film wherein the reciprocal space wavevector \textbf{Q} due to the ordered stripe domains does not evolve continuously, rather exhibits a staircase structure. Resonant X-ray scattering experiments show jumps in the periodicity of the stripe domains as a function of an external magnetic field. When resolved in components, the step change along Q$_x$ was found to be an integral multiple of a minimum step height of 7 nm, which resembles closely to the exchange length of the system. Modeling the magnetic texture in the Fe/Gd thin film as an achiral spin arrangement, we have been able to reproduce the steps in the magnetization using a Landau-Lifshitz spin dynamics calculation. Our results indicate that anisotropy and not the dipolar interaction is the dominant cause for the staircase pattern, thereby revealing the effect of achiral magnetism.Comment: 9 pages, 5 figure

Cluster-Induced Mask Transformers for Effective Opportunistic Gastric Cancer Screening on Non-contrast CT Scans

Gastric cancer is the third leading cause of cancer-related mortality worldwide, but no guideline-recommended screening test exists. Existing methods can be invasive, expensive, and lack sensitivity to identify early-stage gastric cancer. In this study, we explore the feasibility of using a deep learning approach on non-contrast CT scans for gastric cancer detection. We propose a novel cluster-induced Mask Transformer that jointly segments the tumor and classifies abnormality in a multi-task manner. Our model incorporates learnable clusters that encode the texture and shape prototypes of gastric cancer, utilizing self- and cross-attention to interact with convolutional features. In our experiments, the proposed method achieves a sensitivity of 85.0% and specificity of 92.6% for detecting gastric tumors on a hold-out test set consisting of 100 patients with cancer and 148 normal. In comparison, two radiologists have an average sensitivity of 73.5% and specificity of 84.3%. We also obtain a specificity of 97.7% on an external test set with 903 normal cases. Our approach performs comparably to established state-of-the-art gastric cancer screening tools like blood testing and endoscopy, while also being more sensitive in detecting early-stage cancer. This demonstrates the potential of our approach as a novel, non-invasive, low-cost, and accurate method for opportunistic gastric cancer screening.Comment: MICCAI 202

The Effect of Scalp Point Cluster-Needling on Learning and Memory Function and Neurotransmitter Levels in Rats with Vascular Dementia

We observed the effect of scalp point cluster-needling treatment on learning and memory function and neurotransmitter levels in rats with vascular dementia (VD). Permanent ligation of the bilateral carotid arteries was used to create the VD rat model. A Morris water maze was used to measure the rats’ learning and memory function, and the changes in neurotransmitter levels in the rats’ hippocampus were analyzed. The results show that scalp point cluster-needling can increase the VD rat model’s learning and memory score. The VD rat model’s learning and memory score was significantly different when compared with that of the sham operation group P<0.05. Hippocampal acetylcholine (ACh), dopamine (DA), and 5-hydroxytryptamine (5-HT) concentrations significantly decreased in the rat model. Compared with the model group, the scalp point cluster-needling group’s ACh concentration markedly increased and DA and 5-HT levels increased as well. In conclusion, scalp point cluster-needling can improve learning and memory function in VD rats, and its function may be related to an increase in neurotransmitter release

An improved system for competent cell preparation and high efficiency plasmid transformation using different Escherichia coli strains

This paper describes an efficient bacterial transformation system that was established for the preparation of competent cells, plasmid preparation, and for the storage in bacterial stocks in our laboratory. Using this method, a number of different plasmids have been amplified for further experiments. Competent cells for bacterial transformation were prepared by the calcium chloride method with an optimum concentration of 75 mM. Three different strains of Escherichia coli that were tested are DH5&#945;, TG1 and XL1 blue, and the most efficient strain being XL1 blue. The optimal optical density (OD600) range for competent cell preparation varied for each of the strains investigated, and for XL1 blue it was 0.15-0.45; for TG1 it was 0.2-0.5; and for DH5&#945; it was 0.145-0.45. The storage time of competent cells and its correlation to transformation efficiency has been studied, and the result showed that competent cells can be stored at -20&ordm;C for 7 days and at -70&ordm;C for 15 days. Three critical alterations to previous methods have been made, which are the changing of the normal CaCl2 solution to TB solution, the changing of the medium from LB to S.O.C., and addition of DMSO or PEG8000 during transformation of competent cells with plasmids. Changing the medium from LB to S.O.C., resulted in much faster growth of transformants, and the transformation efficiency was increased. Addition of DMSO or PEG8000 raised transformation efficiencies by 100-300 fold. Our improved bacterial transformation system can raise the transformation efficiency about 10³ times, making it becoming a highly efficient bacterial transformation system