Thermal behavior study and experimental testing of deep groove ball bearings

Shuzhi Gao,Yajie Wang,Yimin Zhang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.12

In this study, based on the experimental analysis of heat generation in deep groove ball bearings, the thermal nodes about the deep groove ball bearings is established by using heat network method. The temperature field of the bearing is simulated with finite element software, and the result obtained from the simulation is in good agreement with the comparison of the theoretical calculation results. The bearing test bench was used to analyze the bearing, and the experimental results again proved the effectiveness of the thermal network method. It was found that the bearing speed played a significant role in the working temperature of a bearing, which was consistent to the analysis of the thermal network method, verifying the feasibility of the thermal network method to solve bearing temperature, laying the foundation for the subsequent research on the heat transfer law of motor and rolling bearing.

Inhibitory Abilities of Bacillus Isolates and Their Culture Filtrates against the Gray Mold Caused by Botrytis cinerea on Postharvest Fruit

Xiaomeng Chen,Yajie Wang,Yu Gao,Tongguo Gao,Dongdong Zhang 한국식물병리학회 2019 Plant Pathology Journal Vol.35 No.5

Botrytis cinerea, a major phytopathogenic fungus, has been reported to infect more than 200 crop species worldwide, and it causes massive losses in yield. The aim of this study was to evaluate the inhibitory abilities and effects of Bacillus amyloliquefaciens RS-25, Bacillus licheniformis MG-4, Bacillus subtilis Z-14, and Bacillus subtilis Pnf-4 and their culture filtrates and extracts against the gray mold caused by B. cinerea on postharvest tomato, strawberry, and grapefruit. The results revealed that the cells of Z-14, culture filtrate of RS- 25, and cells of Z-14 showed the strongest biocontrol activity against the gray mold on the strawberry, grape, and tomato fruit, respectively. All the strains produced volatile organic compounds (VOCs), and the VOCs of Pnf-4 displayed the highest inhibition values. Based on headspace solid-phase microextraction in combination with gas chromatography-mass spectrometry, esters accounted for the largest percentage of the VOCs produced by RS-25, MG-4, Z-14, and Pnf-4 (36.80%, 29.58%, 30.78%, and 36.26%, respectively). All the strains showed potent cellulase and protease activities, but no chitinase activity. RS-25, Z-14, and MG-4, but not Pnf-4, grew on chrome azurol S agar, and an orange halo was formed around the colonies. All the strains showed biofilm formation, fruit colonization, and lipopeptide production, which may be the main modes of action of the antagonists against B. cinerea on the fruit. This study provides the basis for developing natural biocontrol agents against the gray mold caused by B. cinerea on postharvest fruit.

Clinical Application Value of Lactobacillus Plantarum PS128 in Patients with Anxiety Disorders

Xiaojuan Meng,Yajie Gao,Hang Qi,Yongyan Ding,Yaqing Sun 대한정신약물학회 2022 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.20 No.3

Objective: PS128 is a novel psycho biotic strain, it has been reported to play an important role in neuropsychiatric disorders. This study investigated the clinical effect of PS128 supplementation on patients with anxiety. Methods: A total of 200 patients with anxiety were recruited, and divided into two groups (n = 100/group). The control group received oral treatment with citalopram, and the PS128 group received PS128 capsules based on citalopram treatment. Hamilton Anxiety Scale (HAMA) and Self-Rating Anxiety Scale (SAS) were used to evaluate the anxiety levels. After 2 months of continuous administration, clinical efficacy was evaluated according to HAMA score. Results: There was no significant difference in HAMA and SAS scores between the two groups before treatment. With the treatment prolonged, the HAMA and SAS score decreased gradually in both control and PS128 groups, and the decrease rate of PS128 group was significantly greater than that of the control group. The clinical effective rates of PS128 group were higher than those in the control group, high levels of clinical cure rate were also detected in the PS128 group. Compared with the control group (22%), the incidence of adverse reactions was significantly reduced for patients in the PS128 group (4%). Conclusion: The treatment effect of citalopram combined with PS128 against anxiety is satisfactory clinically. It can greatly improve the anxiety symptoms of patients, increase the cure rate, reduce adverse reactions.

A Theoretical Study on the Effect of Structural Parameter on Tensile Properties of Helical Auxetic Yarns

Sai Liu,Yajie Gao,Xiaogang Chen,Zhaoqun Du 한국섬유공학회 2019 Fibers and polymers Vol.20 No.8

When auxetic yarns with helical wrapping structure are axially stretched, pressure and friction between the yarncomponents exist during the deformation. The tensile property of auxetic yarns not only depends on the materials of the twocomponents, but also the structure of the yarns. Thus, the structuring effects on the tensile properties were studied bytheoretical modelling with the series arrangement of a linear spring and a Newton dashpot. Besides, analysing theexperimental results by the OriginPro 9 software, the effectiveness of theoretical model was validated and all the values ofcorrelation coefficients were higher than 0.97. The relations between stress and strain were presented and it was expected tobe used for predicting the tensile property of auxetic yarns with different helical angles.

Performance differences of Rhode Island Red, Bashang Long-tail Chicken, and their reciprocal crossbreds under natural cold stress

Xie, Shanshan,Yang, Xukai,Gao, Yahui,Jiao, Wenjie,Li, Xinghua,Li, Yajie,Ning, Zhonghua Asian Australasian Association of Animal Productio 2017 Animal Bioscience Vol.30 No.10

Objective: The Bashang Long-tail chicken (BS), an indigenous Chinese breed, is considered cold tolerant. We selected BS, the Rhode Island Red (RIR), and their reciprocal crossbreds for the present study. The objectives were: i) to validate whether BS is cold tolerant and whether egg production and cold tolerance of crossbreds could be improved; and ii) to determine the physiological characteristics that underlie cold tolerance and favorable egg production performance in cold environments. Methods: A total of 916 chickens were reared in warm and natural cold environments (daily mean ambient temperature varied from $7.4^{\circ}C$ to $26.5^{\circ}C$ in the warm environment and from $-17.5^{\circ}C$ to $27.0^{\circ}C$ in the cold environment). To investigate their adaptability to the cold environment, the egg production performance and body weight were monitored and compared between breeds and environments. The cloacal temperature and serum biochemical parameters were monitored to reveal the physiological characteristics underlie cold tolerance and favorable egg production performance in the cold environment. Results: The warm environment experiment showed that RIR had the highest egg production performance, and that the reciprocal crossbreds had a higher egg production performance than BS. While in the cold environment RIR had the lowest egg production performance, and the reciprocal crossbreds had a higher egg production performance than BS. In the cold environment BS and reciprocal crossbreds had higher triiodothyronine, tetraiodothyronine levels than RIR. At 35 and 39 wk of age, when the ambient temperature was extremely low (varied from $-20^{\circ}C$ to $0^{\circ}C$), serum glucose, follicle-stimulating hormone, luteinizing hormone, estradiol of BS and crossbreds were higher than RIR. Conclusion: Bashang Long-tail chicken has a favorable cold tolerance ability. Crossbreeding with RIR and BS is an effective way to develop cold tolerant chickens with improved egg production performance.

Characterization of a Family 3 Polysaccharide Lyase with Broad Temperature Adaptability, Thermo-alkali Stability, and Ethanol Tolerance

JunPei Zhou,Yanyan Dong,Yajie Gao,Xianghua Tang,Junjun Li,YUN-JUAN YANG,Bo Xu,Zhenrong Xie,Zunxi Huang 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.4

The 774-bp pectate lyase gene plyAI4 from Bacillus sp. I4 was cloned and expressed in E. coli. The gene encodes a 257-residue polypeptide (PlyAI4, 28.3 kDa)with the highest identities of 97.3% with a putative pectate lyase from Bacillus subtilis BSn5 (ADV94306) and 60.3%with an identified pectate lyase of the polysaccharide lyase family (PL) 3 from Paenibacillus amylolyticus 27C64(ADB78774). The purified recombinant PlyAI4 (rPlyAI4)exhibited apparently optimal activity at pH 10.5 ~ 11.0 and 50oC. Compared with the majority of reported alkaline pectate lyases, rPlyAI4 exhibited more residual enzyme activity at 20oC (~45%) or at 70oC (~50%) and better thermostability at 70oC (~60 min half-life at 70oC). In the presence of 20% (v/v) ethanol, pectate lyase activity was enhanced by 0.2 fold. After incubation in 40% (v/v)ethanol at 37oC and pH 8.5 for 1 h, the purified rPelAI4retained more than 75% of the initial activity. Sequence analysis proposed a new signature block, A-D-G-[V/I]-H,for PL 3 pectate lyases. These properties may prove to be important with regards to PlyAI4 for basic research and industrial application.

Effects of Exogenous Organic Acids on the Growth and Antioxidant System of Cosmos bipinnatus under Cadmium Stress

Jiani Hu,Xinyi Gao,Yajie Yue,Xiaoyu Ming,Linjie Yue,Lijuan Yang,Xue Xiao,Xiaofang Yu 한국원예학회 2022 원예과학기술지 Vol.40 No.5

Cadmium pollution in China’s urban green spaces is extremely severe, causing a significant increase in the risk of urban environmental pollution. Applying organic acids under Cd stress conditions improves the activity of the major antioxidant enzymes in the AsA-GSH cycle signi- ficantly. In this study, Cosmos bipinnatus seedlings were cultured in a nutritive medium containing 40 µmol·L-1 Cd. They were subsequently supplemented with different concentrations of citric acid and malic acid (0, 0.5, 1.0, 2.0 mmol L-1 ) to analyze the roles of the organic acids in regulating the AsA-GSH cycle involved in plant resistance to Cd stress. Exogenous organic acids inhibited the growth of C. bipinnatus in a dose-dependent manner. AsA, GSH, and GR in the leaves decreased dramatically at high malic acid concentrations (2 mol L-1 ). The contents of GSH and GR and the APX activities showed a downward trend when the seedlings were treated with 0.5–2 mmol·L-1 of citric acid. However, AsA exhibited contrasting results under these conditions. Notably, both the antioxidant and enzyme activities were reduced considerably to a minimum when the citric acid concentration was 2 mmol·L-1 . Low concentrations of exogenous acids increased the activities of APX and GR in the leaves of C. bipinnatus, thus increasing the contents of ASA and GSH. Such increases boost the efficiency of the ASA-GSH cycle in relieving the toxic effect of cadmium on C. bipinnatus. Cadmium pollution in China’s urban green spaces is extremely severe, causing a significant increase in the risk of urban environmental pollution. Applying organic acids under Cd stress conditions improves the activity of the major antioxidant enzymes in the AsA-GSH cycle signi- ficantly. In this study, Cosmos bipinnatus seedlings were cultured in a nutritive medium containing -1 40 µmol·L Cd. They were subsequently supplemented with different concentrations of citric acid -1 and malic acid (0,0.5,1.0,2.0 mmol L ) to analyze the roles of the organic acids in regulating the AsA-GSH cycle involved in plant resistance to Cd stress. Exogenous organic acids inhibited the growth of C. bipinnatus in a dose-dependent manner. AsA, GSH, and GR in the leaves decreased -1 dramatically at high malic acid concentrations (2 mol L ). The contents of GSH and GR and the -1 APX activities showed a downward trend when the seedlings were treated with 0.5–2 mmol·L of citric acid. However, AsA exhibited contrasting results under these conditions. Notably, both the antioxidant and enzyme activities were reduced considerably to a minimum when the citric acid -1 concentration was 2 mmol·L . Low concentrations of exogenous acids increased the activities of APX and GR in the leaves of C. bipinnatus, thus increasing the contents of ASA and GSH. Such increases boost the efficiency of the ASA-GSH cycle in relieving the toxic effect of cadmium on C. bipinnatus.

Inhibitory Abilities of Bacillus Isolates and Their Culture Filtrates against the Gray Mold Caused by Botrytis cinerea on Postharvest Fruit

Chen, Xiaomeng,Wang, Yajie,Gao, Yu,Gao, Tongguo,Zhang, Dongdong The Korean Society of Plant Pathology 2019 Plant Pathology Journal Vol.35 No.5

Botrytis cinerea, a major phytopathogenic fungus, has been reported to infect more than 200 crop species worldwide, and it causes massive losses in yield. The aim of this study was to evaluate the inhibitory abilities and effects of Bacillus amyloliquefaciens RS-25, Bacillus licheniformis MG-4, Bacillus subtilis Z-14, and Bacillus subtilis Pnf-4 and their culture filtrates and extracts against the gray mold caused by B. cinerea on postharvest tomato, strawberry, and grapefruit. The results revealed that the cells of Z-14, culture filtrate of RS-25, and cells of Z-14 showed the strongest biocontrol activity against the gray mold on the strawberry, grape, and tomato fruit, respectively. All the strains produced volatile organic compounds (VOCs), and the VOCs of Pnf-4 displayed the highest inhibition values. Based on headspace solid-phase microextraction in combination with gas chromatography-mass spectrometry, esters accounted for the largest percentage of the VOCs produced by RS-25, MG-4, Z-14, and Pnf-4 (36.80%, 29.58%, 30.78%, and 36.26%, respectively). All the strains showed potent cellulase and protease activities, but no chitinase activity. RS-25, Z-14, and MG-4, but not Pnf-4, grew on chrome azurol S agar, and an orange halo was formed around the colonies. All the strains showed biofilm formation, fruit colonization, and lipopeptide production, which may be the main modes of action of the antagonists against B. cinerea on the fruit. This study provides the basis for developing natural biocontrol agents against the gray mold caused by B. cinerea on postharvest fruit.

Myocardial Blood Flow Quantified by Low-Dose Dynamic CT Myocardial Perfusion Imaging Is Associated with Peak Troponin Level and Impaired Left Ventricle Function in Patients with ST-Elevated Myocardial Infarction

Jingwei Pan,Mingyuan Yuan,Mengmeng Yu,Yajie Gao,Chengxing Shen,Yining Wang,Bin Lu,Jiayin Zhang 대한영상의학회 2019 Korean Journal of Radiology Vol.20 No.5

Objective: To investigate the association of myocardial blood flow (MBF) quantified by dynamic computed tomography (CT) myocardial perfusion imaging (MPI) with troponin level and left ventricle (LV) function in patients with ST-segment elevated myocardial infarction (STEMI). Materials and Methods: Thirty-five STEMI patients who successfully had undergone reperfusion treatment within 1 week of their infarction were consecutively enrolled. All patients were referred for dynamic CT-MPI. Serial high-sensitivity troponin T (hs-TnT) levels and left ventricular ejection fraction (LVEF) measured by echocardiography were recorded. Twenty-six patients with 427 segments were included for analysis. Various quantitative parameters derived from dynamic CT-MPI were analyzed to determine if there was a correlation between hs-TnT levels and LVEF on admission and again at the 6-month mark. Results: The mean radiation dose for dynamic CT-MPI was 3.2 ± 1.1 mSv. Infarcted territories had significantly lower MBF (30.5 ± 7.4 mL/min/100 mL versus 73.4 ± 8.1 mL/min/100 mL, p < 0.001) and myocardial blood volume (MBV) (2.8 ± 0.9 mL/100 mL versus 4.2 ± 1.1 mL/100 mL, p = 0.044) compared with those of reference territories. MBF showed the best correlation with the level of peak hs-TnT (r = -0.682, p < 0.001), and MBV showed a moderate correlation with the level of peak hs-TnT (r = -0.437, p = 0.026); however, the other parameters did not show any significant correlation with hs-TnT levels. As for the association with LV function, only MBF was significantly correlated with LVEF at the time of admission (r = 0.469, p = 0.016) and at 6 months (r = 0.585, p = 0.001). Conclusion: MBF quantified by dynamic CT-MPI is significantly inversely correlated with the level of peak hs-TnT. In addition, patients with lower MBF tended to have impaired LV function at the time of their admission and at 6 months.