H2 Metabolism revealed by metagenomic analysis of subglacial sediment from East Antarctica

Zhifeng Yang,Yu Zhang,Yongxin Lv,Wenkai Yan,Xiang Xiao,Bo Sun,Hongmei Ma 한국미생물학회 2019 The journal of microbiology Vol.57 No.12

Subglacial ecosystems harbor diverse chemoautotrophic microbial communities in areas with limited organic carbon, and lithological H2 produced during glacial erosion has been considered an important energy source in these ecosystems. To verify the H2-utilizing potential there and to identify the related energy-converting metabolic mechanisms of these communities, we performed metagenomic analysis on subglacial sediment samples from East Antarctica with and without H2 supplementation. Genes coding for several [NiFe]- hydrogenases were identified in raw sediment and were enriched after H2 incubation. All genes in the dissimilatory nitrate reduction and denitrification pathways were detected in the subglacial community, and the genes coding for these pathways became enriched after H2 was supplied. Similarly, genes transcribing key enzymes in the Calvin cycle were detected in raw sediment and were also enriched. Moreover, key genes involved in H2 oxidization, nitrate reduction, oxidative phosphorylation, and the Calvin cycle were identified within one metagenome-assembled genome belonging to a Polaromonas sp. As suggested by our results, the microbial community in the subglacial environment we investigated consisted of chemoautotrophic populations supported by H2 oxidation. These results further confirm the importance of H2 in the cryosphere.

Effects of vertebral number variations on carcass traits and genotyping of Vertnin candidate gene in Kazakh sheep

Zhang, Zhifeng,Sun, Yawei,Du, Wei,He, Sangang,Liu, Mingjun,Tian, Changyan Asian Australasian Association of Animal Productio 2017 Animal Bioscience Vol.30 No.9

Objective: The vertebral number is associated with body length and carcass traits, which represents an economically important trait in farm animals. The variation of vertebral number has been observed in a few mammalian species. However, the variation of vertebral number and quantitative trait loci in sheep breeds have not been well addressed. Methods: In our investigation, the information including gender, age, carcass weight, carcass length and the number of thoracic and lumbar vertebrae from 624 China Kazakh sheep was collected. The effect of vertebral number variation on carcass weight and carcass length was estimated by general linear model. Further, the polymorphic sites of Vertnin (VRTN) gene were identified by sequencing, and the association of the genotype and vertebral number variation was analyzed by the one-way analysis of variance model. Results: The variation of thoracolumbar vertebrae number in Kazakh sheep (18 to 20) was smaller than that in Texel sheep (17 to 21). The individuals with 19 thoracolumbar vertebrae (T13L6) were dominant in Kazakh sheep (79.2%). The association study showed that the numbers of thoracolumbar vertebrae were positively correlated with the carcass length and carcass weight, statistically significant with carcass length. To investigate the association of thoracolumbar vertebrae number with VRTN gene, we genotyped the VRTN gene. A total of 9 polymorphic sites were detected and only a single nucleotide polymorphism (SNP) (rs426367238) was suggested to associate with thoracic vertebral number statistically. Conclusion: The variation of thoracolumbar vertebrae number positively associated with the carcass length and carcass weight, especially with the carcass length. VRTN gene polymorphism of the SNP (rs426367238) with significant effect on thoracic vertebral number could be as a candidate marker to further evaluate its role in influence of thoracolumbar vertebral number.

Contents of Endogenous Hormones in Normal and Malformed Immature Cucumber Fruits

Xiaolei Sun,Sanjun Gu,Xiaopeng Chen,Zhifeng Wang,Qiwei Cao,Xingsheng Li 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Experimental and Numerical Simulation Study on Mechanical Properties of Shallow Slope Root-soil Composite in Qinghai Area

Yuan Sun,Hui Li,Zhifeng Cheng,Jianpeng Dong,Yawei Wang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.7

Natural disasters such as landslides often occur in Qinghai under the double deterioration ofearthquake and freeze-thaw cycles, ecological slope protection is an effective way to preventand control this type of disaster. In this paper, the mechanical properties of root-soilcomposites are investigated experimentally using triaxial apparatus and dynamic single shear(DSS) apparatus, and based on the discrete element method, a contact model more suitablefor reinforced soil materials is proposed to study the dynamic properties of root-soilcomposites under cyclic shear from a fine viewpoint. Based on the results of the study, thefollowing conclusions were drawn: 1) The presence of roots under the action of freeze-thawcycles increases the strength properties of the soil. At the same number of freeze-thaw cycles,the shear strength and cyclic resistance of the root-soil composites are higher than those of theloess. And the strength of the root-soil composites decreases with the increase of the numberof freeze-thaw cycles and then flattens out; 2) The proposed contact model can bettersimulate the softening effect of reinforced loess material under cyclic shear, which is moresuitable for simulating the mechanical behavior of loess and laying the foundation for furtherstudy of reinforced loess material from a fine viewpoint.; 3) The presence of the root systemwill improve the stability of the slope soil, and the root system will have a positive effect on theshear strength of the soil when the moisture content is within a certain range. The presence ofthe root system also increases the cyclic resistance of the soil. Under the same cyclic shearstress conditions, the number of damage cycles of the root-soil composites is higher than thatof the loess, the cumulative shear strain is less than that of the loess. However, the root systemno longer exerts positive effects under saturated conditions. The research results can providesome guidance for the construction of ecological slopes in loess areas, and provide a new wayto investigate the dynamic properties of root-soil composites from a fine viewpoint.

The delamination of carbon fiber reinforced composites during cutting by flexible linear shaped charge

Jing Sun,Zhiguo Ma,Zhifeng Zhang,Fei Weng,Rong Chen 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.4

The delamination is a typical phenomenon when the carbon fiber reinforced composites (CFRC) undergoes blasting impact loading and the delamination will reduce both the strength and stiffness of the laminates, which can lead to catastrophic consequences while used as rocket skin. In this paper, the response of CFRC laminate is cut by flexible linear shaped charge (FLSC) and the delamination behavior of the CFRC is analyzed and discussed. The displacement interferometer system for any reflector (DISAR) is used to monitor the velocity of characteristic points of the laminate subjected to FLSC. Finite element analysis has been conducted to explain the mechanisms of delamination. Based on the numerical simulation, the influences of structural design parameters on the delamination effect of the CFRC after cutting are investigated. The results show that a large number of debris are produced at the center of the explosion and a small amount of large debris is produced at weakening groove on both sides. The delamination effect is greatly affected by the inter-laminar tensile strength and thickness of composite laminate, but it is not significantly affected by the linear density of the FLSC and stand-off.

Simulation of particulate matter movement characteristics in multiphase flow field system

Zhangliang Xu,Zhifeng Li,Maochuan Sun 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.8

An innovative separation system based on dielectric electrophoresis (DEP-on-achip system) is proposed to separate different particulate matters. A discrete phase model (DPM) and coupling model was utilized to simulate the movement characteristics in liquid-solid two phase flows and gas-liquid-solid three phase flows, respectively. In liquid-solid fluid systems, the effect of the liquid viscosity and density on the movement displacement of particles was studied. In gas-liquid-solid fluid systems, the effect of physical parameters, such as inlet velocity, liquid viscosity, liquid density and surface tension force, on the trajectory of PM2.5 (particulate matter 2.5) and PM10 was discussed. Conclusively, the theoretical separation time of the DEP-on-a-chip system is successfully achieved at the second level. The optimized physical parameters with the inlet velocity around 1.0 m/s, the liquid viscosity of 1×10 -5 Pa·s, the liquid density of 1500 kg/m 3 and the surface tension of 0.065 N/m for the separation system are established.

Energy-Efficient Algorithm for Assigning Verification Tasks in Cloud Storage

( Guangwei Xu ),( Zhifeng Sun ),( Cairong Yan ),( Xiujin Shi ),( Yue Li ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.1

Mobile Cloud Computing has become a promising computing platform. It moves users` data to the centralized large data centers for users` mobile devices to conveniently access. Since the data storage service may not be fully trusted, many public verification algorithms are proposed to check the data integrity. However, these algorithms hardly consider the huge computational burden for the verifiers with resource-constrained mobile devices to execute the verification tasks. We propose an energy-efficient algorithm for assigning verification tasks (EEAVT) to optimize the energy consumption and assign the verification tasks by elastic and customizable ways. The algorithm prioritizes verification tasks according to the expected finish time of the verification, and assigns the number of checked blocks referring to devices` residual energy and available operation time. Theoretical analysis and experiment evaluation show that our algorithm not only shortens the verification finish time, but also decreases energy consumption, thus improving the efficiency and reliability of the verification.

Particle Swarm Optimization based on Vector Gaussian Learning

( Jia Zhao ),( Li Lv ),( Hui Wang ),( Hui Sun ),( Runxiu Wu ),( Jugen Nie ),( Zhifeng Xie ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.4

Gaussian learning is a new technology in the computational intelligence area. However, this technology weakens the learning ability of a particle swarm and achieves a lack of diversity. Thus, this paper proposes a vector Gaussian learning strategy and presents an effective approach, named particle swarm optimization based on vector Gaussian learning. The experiments show that the algorithm is more close to the optimal solution and the better search efficiency after we use vector Gaussian learning strategy. The strategy adopts vector Gaussian learning to generate the Gaussian solution of a swarm`s optimal location, increases the learning ability of the swarm`s optimal location, and maintains the diversity of the swarm. The method divides the states into normal and premature states by analyzing the state threshold of the swarm. If the swarm is in the premature category, the algorithm adopts an inertia weight strategy that decreases linearly in addition to vector Gaussian learning; otherwise, it uses a fixed inertia weight strategy. Experiments are conducted on eight well-known benchmark functions to verify the performance of the new approach. The results demonstrate promising performance of the new method in terms of convergence velocity and precision, with an improved ability to escape from a local optimum.

A Learning Control Strategy for Robot-assisted Bathing via Impedance Sliding Mode Technique With Non-repetitive Tasks

Yuexuan Xu,Xin Guo,Bokai Xuan,Hao Sun,Gaowei Zhang,Jian Li,Xingyu Huo,Zhifeng Gu 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.3

This paper investigates an impedance-based iterative learning sliding mode control scheme for robotassisted bathing, taking into consideration scenarios with unknown model parameters. Initially, the utilization ofimpedance control is not confined to merely adjusting the desired trajectory but is also instrumental in ensuringactive compliance control during the robot-assisted bathing procedure. Furthermore, an iterative learning control(ILC) is devised to estimate the iteration-invariant dynamic parameters, which are intricate and challenging to precisely ascertain in practical applications. To mitigate the effect of divergent initial conditions in ILC, a trajectoryreconstruction method is introduced, thus ensuring the convergence of tracking errors even when starting from random initial states. Moreover, an adaptive sliding mode control mechanism is proposed to counteract non-parametricexternal disturbances and the torque generated through human-machine interaction during the bathing process. Theconvergence of the double closed-loop system in both the time and iterative domains is demonstrated through theapplication of the composite energy function method. Eventually, the efficacy and superiority of the control strategyoutlined in this paper are jointly verified through co-simulation employing MATLAB and ADAMS.

Response of Esophagus to High and Low Temperatures in Patients With Achalasia

( Yutang Ren ),( Meiyun Ke ),( Xiucai Fang ),( Liming Zhu ),( Xiaohong Sun ),( Zhifeng Wang ),( Ruifeng Wang ),( Zhao Wei ),( Ping Wen ),( Haiwei Xin ),( Min Chang ) 대한소화기기능성질환·운동학회 2012 Journal of Neurogastroenterology and Motility (JNM Vol.18 No.4

Background/Aims Achalasia patients would feel exacerbated dysphagia, chest pain and regurgitation when they drink cold beverages or eat cold food. But these symptoms would relieve when they drink hot water. Reasons are unknown. Methods Twelve achalasia patients (mean age, 34 ± 10 years, F:M, 3:9) who never had any invasive therapies were chosen from Peking Union Medical College Hospital. They were asked to fill in the questionnaire on eating habits including food temperature and related symptoms and to receive high-resolution manometry examination. The exam was done in 2 separated days, at swallowing room temperature (25oC) then hot (50oC) water, and at room temperature (25oC) then cold (2oC) water, respectively. Parameters associated with esophageal motility were analyzed. Results Most patients (9/12) reported discomfort when they ate cold food. All patients reported no additional discomfort when they ate hot food. Drinking hot water was effective in 5/8 patients who ever tried to relieve chest pain attacks. On manometry, cold water increased lower esophageal sphincter (LES) resting pressure (P = 0.003), and prolonged the duration of esophageal body contraction (P = 0.002). Hot water decreased LES resting pressure and residue pressure during swallow (P = 0.008 and P = 0.002), increased LES relaxation rate (P = 0.029) and shortened the duration of esophageal body contraction (P = 0.003). Conclusions Cold water could increase LES resting pressure, prolong the contraction duration of esophageal body, and exacerbate achalasia symptoms. Hot water could reduce LES resting pressure, assist LES relaxation, shorten the contraction duration of esophageal body and relieve symptoms. Thus achalasia patients are recommended to eat hot and warm food and avoid cold food. (J Neurogastroenterol Motil 2012,18:391-398)