Disease vector occurrence and ecological characteristics of chiggers on the chestnut white-bellied rat Niviventer fulvescens in Southwest China between 2001 and 2019

Yan-Ling Chen,Xian-Guo Guo,Wen-Yu Song,Tian-Guang Ren,Lei Zhang,Rong Fan,Cheng-Fu Zhao,Zhi-Wei Zhang,Wenge Dong,Xiao-Bin Huang,Dao-chao Jin 대한기생충학ㆍ열대의학회 2023 The Korean Journal of Parasitology Vol.61 No.3

Chigger mites are the vector of scrub typhus. This study estimates the infestation status and ecological characteristics of chiggers on the chestnut white-bellied rat Niviventer fulvescens in Southwest China between 2001 and 2019. Chiggers were identified under the microscope, and infestation indices were calculated. The Preston’s log-normal model was used to fit the curve of species abundance distribution. A total of 6,557 chiggers were collected in 136 of 342 N. fulvescens rats, showing high overall infestation indices (prevalence=39.8%, mean abundance=19.2, mean intensity=48.2) and high species diversity (S =100, H’=3.0). Leptotrombidium cangjiangense, Neotrombicula japonica, and Ascoschoengastia sifanga were the three dominant chigger species (constituent ratio=42.9%; 2,736/6,384) and exhibited an aggregated distribution among different rat individuals. We identified 100 chigger species, with 3 of them (Leptotrombidium scutellare, Leptotrombidium wenense, and Leptotrombidium deliense) as the main vectors of scrub typhus in China and nine species as potential vectors of this disease. Disease vector occurrence on N. fulvescens may increase the risk of spreading scrub typhus from rats to humans. Chigger infestation on N. fulvescens varied significantly in different environments. The species abundance distribution showed a log-normal distribution pattern. The estimated number of chigger species on N. fulvescens was 126 species.

Effect of Strain Rate on the Microstructure and Texture Evolution of the ZK60 Alloy Sheets

Hongge Yan,Qin Wu,Jihua Chen,Weijun Xia,Min Song,Bin Su,Biao Huang 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.3

The dynamic recrystallization (DRX), precipitation and texture evolution of the ZK60 alloy sheets rolled at 300 °C withdifferent strain rates were studied, and the effects of texture on the plasticity were also clarified. The DRX grain sizes at fivestrain rates (5–25 s−1) are 1.4 μm, 1.2 μm, 1.8 μm, 2.4 μm and 2.8 μm, respectively, while the DRX volume fractions are35.8%, 75.0%, 82.0%, 88.0% and 93.0%, respectively. The maximum intensity values of the (0002) texture are 7.91, 8.22,7.64, 5.76 and 5.34 at five strain rates, respectively. The strongest (0002) texture is observed at the strain rate of 10 s−1,which is related to the relatively low DRX volume fraction and the precipitation density. The tensile strength (UTS) and yieldstrength (YS) increases firstly and then decreases, while the elongation (EL) gradually increases with increasing the strainrate, suggesting that the plasticity of the alloy sheet can be improved by decreasing the basal texture intensity and increasingthe dispersion degree of the basal texture. The optimal comprehensive mechanical properties are obtained at the strain rateof 10 s−1, with UTS of 358 MPa, YS of 291 MPa and EL of 21.5%.

Distribution Characteristics of 3,369 Chinese Colorectal Cancer Patients for Gender, Age, Location and Tumor Size During Colonoscopy

Cai, Bin,Wang, Mu-Yong,Liao, Kai,Xu, Yan-Song,Wei, Wei-Yuan,Zhuang, Yuan,Zhang, Sen Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.20

Background: Studies have shown the existence of gender- and age-related differences in the incidence and anatomic distribution of colorectal cancers. The purposes of this study were to analyze the distribution characteristics of colorectal cancer patients regarding gender, age, location and tumor size in the course of colonoscopy. Materials and Methods: All colorectal cancer patients who underwent colonoscopy in the First Affiliated Hospital of Guangxi Medical University from 2003 to 2012 were included in our retrospective study. Demographic information (age and gender) and colonoscopy report information (tumor size and location) were collected and analyzed. To compare the gender differences in tumor location and tumor size, as well as the size differences in tumor location, the chi-square test was used. Results: A total of 3, 369 colorectal cancer patients (2, 007 men vs 1, 362 women) were included in our study. Statistical analysis showed there was no gender difference in the anatomic distribution of the tumors (p>0.05). However, there was a gender difference in tumor size (p<0.05). In addition, our study found there was a significant difference in tumor size between rectal and colon tumors (p<0.001). Conclusions: There was no gender difference in the anatomic distribution of colorectal tumors. In addition, tumors observed in men were larger than in women.

The effect of light on follicular development in laying hens

Cheng, Shi Bin,Li, Xian Qiang,Wang, Jia Xiang,Wu, Yan,Li, Peng,Pi, Jin Song Asian Australasian Association of Animal Productio 2021 Animal Bioscience Vol.34 No.11

Objective: The oxidative stress status and changes of chicken ovary tissue after shading were studied, to determine the mechanism of the effect of shading on follicular development. Methods: Twenty healthy laying hens (40 weeks old) with uniform body weight and the same laying rate were randomly divided into two groups (the shading group and normal light group). In the shading group, the cage was covered to reduce the light intensity inside the cage to 0 without affecting ventilation or food intake. The normal lighting group received no additional treatment. After 7 days of shading, oxidative stress related indicators and gene expression were detected. Results: Analysis of paraffin and ultrathin sections showed that apoptosis of ovarian granulosa cells (GCs) increased significantly after light shading. Enzyme linked immunosorbent assay results revealed that the levels of total antioxidant capacity, malondialdehyde, superoxide dismutase (SOD), glutathione, catalase (CAT), and other substances in the sera, livers, ovaries, and follicular GCs of laying hens increased significantly after shading for 7 days; and reactive oxygen species (ROS) levels in the livers of laying hens also increased significantly. ROS in the serum, ovarian and GCs also increased. After shading for 7 days, the levels of 8-hydroxy-2 deoxyguanosine in the sera and ovarian tissues of laying hens increased significantly. Cell counting kit-8 detection showed that the proliferation activity of GCs in layer follicles decreased after shading for 7 days; the expression level of the anti-apoptotic gene B-cell lymphoma-2 in ovarian tissue and follicular GCs was significantly reduced, and the expression levels of pro-apoptotic caspase 3 (casp3), and SOD, glutathione peroxidase 2 (GPX2), and CAT were all significantly increased. Conclusion: Oxidative stress induced by shading light has a serious inhibitory effect on follicular development during reproduction in laying hens.

Vertical Vibration of Strip Mill with the Piecewise Nonlinear Constraint arising from Hydraulic Cylinder

Fei Liu,Bin Liu,Hao-ran Liu,Yan-ling Gong,Song-jun Wang 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

Vertical vibration model of strip mill is established by considering piecewise nonlinear constraint arising from hydraulic cylinder. The approximate analytical solution of the model is obtained by incremental harmonic balance (IHB) method. The harmonic frequencies not conducive to stability are produced because the nonlinearity of the piecewise constraint. Bifurcation behavior of the system changes with external excitation amplitude and frequency ratio, intermittent chaos and periodic window are appeared alternately, the chaos region enlarged with the increasing piecewise interval. Compared with the piecewise linear constraint, the region of chaotic motion is widened obviously under the nonlinear constraint. Moreover, the critical condition of bifurcation and chaos behavior can be obtained from maximum Lyapunov exponent (MLE).

Intersubband Transitions in Nonpolar GaN-based Resonant Phonon Depopulation Multiple-Quantum Wells for Terahertz Emissions

Ya-Feng Song,Xiong-Xiong Kong,Wei-Bin Tang,Zhong-Qiang Suo,Huan Zhang,Chen-Yang Li,Qian Jia,Cai-Xia Xue,Yan-Wu Lu,Chao-Pu Yang 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.74 No.11

We investigate the polarization effect in intersubband transitions in polar and nonpolar GaN-based multiple-quantum well (MQW) structures for terahertz (THz) emissions by using systematic comparisons and design a nonpolar GaN/Al$_{0.2}$Ga$_{0.8}$N two-well-based MQW structure with an emitting photon of 7.27 THz (30.07 meV). Its lower energy separation (92.7 meV) matches the resonant phonon depopulation condition for better population inversion. It shows a lower threshold current density $J\rm_{th}$ at all temperatures (1.548 kA/cm$^2$ at 90 K) and a higher output power of up to 86.1 mW at 5.8 K and 33.6 mW at 100 K. Our results for the polar GaN MQW are very close to the experimental data in the literature. We find that the $J\rm_{th}$ of the nonpolar GaN MQW increases more slowly than that of the polar GaN MQW as temperature increases, indicating the nonpolar GaN MQW may be a worth-trying direction for improving the operation temperature. These results can provide meaningful references for the design and fabrication of nonpolar GaN-based THz MQW or quantum cascade structures.

Effect of synthesis conditions on the particle size and morphology of YAG powder

Jie-Guang Song,Fang Wang,Ming-Han Xu,Yin-Yan Ju,Yang-Liang Li,Shi-Bin Li,Gang-Chang Ji 한양대학교 세라믹연구소 2012 Journal of Ceramic Processing Research Vol.13 No.2

Yttrium aluminum garnet (YAG) is currently a widely applied structural and functional material. To prepare highperformance YAG ceramics we prepared pure YAG powder, after calcining the precursor at 1100 ºC, by co-precipitation with ammonia as the precipitant and aluminum nitrate as well as yttrium nitrate as raw materials. The preparation conditions for the YAG precursor were a pH of 9, a titration rate of 10 ml/ minute and a reaction time of 60 minutes. The mean paricle size of the YAG powder was 11ìm. The mean particle size for the YAG powder increased with an increase in the pH and at a higher pH the YAG particles were more irregular in shape. The mean particle size and particle size distribution range of the YAG powder increased with an increase in the titration rate. For the YAG powder with a higher mean particle size, the particle size distribution range was wider but the size of most YAG particles was still small and the YAG particles were nearly spherical.

Preparation and properties of ZrB2-YAG-Al2O3 ceramics

Jie-Guang Song,Gang-Chang Ji,Shi-Bin Li,Yang-Liang Li,Da-Ming Du,Lian-Meng Zhang,Yin-Yan Ju 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.4

ZrB2, YAG and Al2O3 are widely applied because of some excellent properties, but ZrB2 is easily oxidized in high-temperature air. To achieve better properties in ZrB2 ceramics, high-density ZrB2-YAG-Al2O3 ceramics were prepared. Below 1000℃, the shrinkage of ZrB2-YAG-Al2O3 ceramics is less than that of ZrB2-YAG ceramics. From 1000℃ to 1600℃, the second largest shrinkage occurs. Above 1600℃, the shrinkage of ZrB2-YAG-Al2O3 ceramics is more than that of ZrB2-YAG ceramics. The fracture toughness of sintered ceramics from coated raw materials is higher than that of sintered ceramics with mixed raw materials with the same phases and phase content, the fracture toughness of ZrB2-YAG-Al2O3 ceramics is higher than that of ZrB2-YAG ceramics with the same raw materials. The weight gain of all types of ceramics is increased with all increase in the oxidation temperature, the weight gain of ceramics is reduced with all increase in the YAG-Al2O3 content and Al2O3 proportion, especially above 1500℃. ZrB2, YAG and Al2O3 are widely applied because of some excellent properties, but ZrB2 is easily oxidized in high-temperature air. To achieve better properties in ZrB2 ceramics, high-density ZrB2-YAG-Al2O3 ceramics were prepared. Below 1000℃, the shrinkage of ZrB2-YAG-Al2O3 ceramics is less than that of ZrB2-YAG ceramics. From 1000℃ to 1600℃, the second largest shrinkage occurs. Above 1600℃, the shrinkage of ZrB2-YAG-Al2O3 ceramics is more than that of ZrB2-YAG ceramics. The fracture toughness of sintered ceramics from coated raw materials is higher than that of sintered ceramics with mixed raw materials with the same phases and phase content, the fracture toughness of ZrB2-YAG-Al2O3 ceramics is higher than that of ZrB2-YAG ceramics with the same raw materials. The weight gain of all types of ceramics is increased with all increase in the oxidation temperature, the weight gain of ceramics is reduced with all increase in the YAG-Al2O3 content and Al2O3 proportion, especially above 1500℃.

Oxidation behavior of YAG-ZrB2 ceramics prepared by spark plasma sintering

Jie-Guang Song,Da-Ming Du,Yin-Yan Ju,Yang-Liang Li,Shi-Bin Li,Gang-Chang Ji 한양대학교 세라믹연구소 2010 Journal of Ceramic Processing Research Vol.11 No.4

ZrB2 and YAG are widely applied because of some excellent properties, but ZrB2 is easily oxidized in high-temperature air. To make ZrB2 ceramics have better oxidation resistance, high-density YAG-ZrB2 ceramics were prepared. The oxidation behavior of YAG-ZrB2 ceramics is investigated at different temperatures. The results indicate that the enhanced weight change differs according to the temperature range, slightly in the temperature 900-1000oC, sharply from 1100-1300 and smoothly above 1300oC. The weight change rate of YAG-ZrB2 ceramics is increased by prolonging the oxidation time, but the weight change rate of YAG-ZrB2 ceramics is gradually reduced. The oxidation layer is porous as compared to the YAG-ZrB2 ceramics layer.

Effect of raw materials on the properties of ZrB2-YAG-Al2O3 multi-phase ceramics

Jie-Guang Song,Fang Wang,Da-Ming Du,Yin-Yan Ju,Shi-Bin Li,Gang-Chang Ji,Lian-Meng Zhang 한양대학교 세라믹연구소 2014 Journal of Ceramic Processing Research Vol.15 No.2

ZrB2 belongs to a class of ceramics defined ultra-high-temperature ceramics with extremely high melting temperatures, but ZrB2 ceramics is difficultly sintered and easily oxidized. To make ZrB2 ceramics possess the high relative density and the better oxidation resistance. The effects of raw materials on the properties of ZrB2 composite were investigated. YAG and Al2O3 help for the densification of ZrB2 ceramics. Fracture toughness of sintered ceramics with coated powder is higher than that of sintered ceramics with mixed powder. The mechanical property of ZrB2-YAG-Al2O3 materials is higher than that of ZrB2-YAG materials. Oxidation layer thickness of sintered ceramics with coated powder is thinner than that of sintered ceramics with mixed powder. These results show the sintered ZrB2 based multi-phase ceramics with coated microstructure help to increase the mechanical properties and oxidation resistance. The oxidation resistance of ZrB2-YAG-Al2O3 ceramics is better than that of ZrB2-YAG materials.