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Search Results: 1 - 10 of 28822 matches for " Xuejun Sun "
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Recent Advances in Finite Element Applications in Artificial Lumbar Disc Replacement  [PDF]
Zhenjun Zhang, Yitao Sun, Xuejun Sun, Yang Li, Zhenhua Liao, Weiqiang Liu
Journal of Biomedical Science and Engineering (JBiSE) , 2016, DOI: 10.4236/jbise.2016.910B001
As a new choice for the treatment of degenerative lumbar disease, artificial lumbar disc replacement has been widely used in clinical surgery. The finite element is a very effective method to predict and simulate the surgery effect. The purpose of this paper is to review the applications of finite element in artificial lumbar disc replacement, such as design of artificial lumbar disc prosthesis, risk and effect evaluation of artificial lumbar disc replacement, and assessment of operation methods. Lastly, we discuss the future development of finite element method applied in this field, including personalized design of the prosthesis, postoperative behavior guide, and artificial lumbar disc replacement combined with fusion surgery. In conclusion, as an invaluable complement to biomechanical experiments and clinical studies, the finite element method makes important contributions to our understanding of biomechanics of intervertebral disc, and plays an important role in the field of artificial lumbar disc replacement.
Molecular Hydrogen Is Involved in Phytohormone Signaling and Stress Responses in Plants
Jiqing Zeng, Mingyong Zhang, Xuejun Sun
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0071038
Abstract: Molecular hydrogen (H2) metabolism in bacteria and algae has been well studied from an industrial perspective because H2 is viewed as a potential future energy source. A number of clinical trials have recently reported that H2 is a therapeutic antioxidant and signaling molecule. Although H2 metabolism in higher plants was reported in some early studies, its biological effects remain unclear. In this report, the biological effects of H2 and its involvement in plant hormone signaling pathways and stress responses were determined. Antioxidant enzyme activity was found to be increased and the transcription of corresponding genes altered when the effects of H2 on the germination of mung bean seeds treated with phytohormones was investigated. In addition, upregulation of several phytohormone receptor genes and genes that encode a few key factors involved in plant signaling pathways was detected in rice seedlings treated with HW. The transcription of putative rice hydrogenase genes, hydrogenase activity, and endogenous H2 production were also determined. H2 production was found to be induced by abscisic acid, ethylene, and jasmonate acid, salt, and drought stress and was consistent with hydrogenase activity and the expression of putative hydrogenase genes in rice seedlings. Together, these results suggest that H2 may have an effect on rice stress tolerance by modulating the output of hormone signaling pathways.
Study on Dormancy Mechanism and Breaking Dormancy Method of Viburnum sargentii Seeds  [PDF]
Qian Zhang, Ying Li, Xia Sun, Shiyan Xing, Wei Cong, Xuejun Liu
American Journal of Plant Sciences (AJPS) , 2019, DOI: 10.4236/ajps.2019.101007
Abstract: Under untreated conditions, the germination rate of Viburnum sargentii seeds is very low. By exploring the relationship between the dynamic changes of physicochemical indicators and endogenous hormones and seed germination during the dormancy and germination of Viburnum sargentii seeds, the mechanism of seed germination of Viburnum sargentii was determined, which provided a theoretical basis for its extensive promotion and development. The contents of soluble sugar and soluble starch were determined by anthrone colorimetry. The soluble protein
Lactulose: an effective preventive and therapeutic option for ischemic stroke by production of hydrogen
Xiao Chen, Xiao Zhai, Zhimin Kang, Xuejun Sun
Medical Gas Research , 2012, DOI: 10.1186/2045-9912-2-3
Abstract: Currently stroke is the second leading cause of death in the Western world, ranking after heart diseases and before cancer [1], causing 10% of deaths worldwide [2]. It is estimated that stroke could soon be the most common cause of death worldwide [3]. An ischemic stroke can be due to ischemia (lack of blood flow) caused by blockage (thrombosis, arterial embolism), which may lead to rapidly developing loss of brain functions as a result of disturbance in the blood supply to the brain [4]. Stroke can affect patients physically, mentally, emotionally, or a combination of the three and bring heavy burdens to society.Ischemia induces production of reactive oxygen species (ROS), which can react with and damage a number of cellular and extracellular elements. Evidence has accumulated showing that ROS are involved in cerebral ischemia and reperfusion. During cerebral ischemia, cerebral blood flow was partially or completely cut off in brain regions supplied by the occluded vessels. Reoxygenation due to spontaneous or thrombolytic reperfusion offers oxygen as a substrate for a number of enzymatic oxidation, constantly generating ROS like superoxide anion radicals(O2·-) and hydrogen peroxide(H2O2) [5]. ROS are known to be able to result in macromolecular damages including lipid peroxidation, protein oxidation, and DNA oxidation, which result in ischemic brain injury [6]. Clinically, a number of recent studies have revealed that stroke and oxidative stress are closely related and excess oxidative stress may have deleterious effects on clinical outcome in acute ischemic stroke [7,8]. Therefore, antioxidants have been considered in prevention and treatment of stroke and certain agents with antioxidative effects did have neuroprotective effects [9].In recent years, experimental evidences have documented that without influencing other less potent ROS, important in intracellular signaling, molecular hydrogen possesses the ability to selectively neutralize ONOO- and ?OH, the most c

Sun Lu,Deng Xuejun,

力学学报 , 1996,
Abstract: Integral transform method is used to obtain general solution for steady dynamic response of infinite plate on an elastic foundation causing by a moving arbitrary load. Dynamic response of plate suffering with a moving stationary random load is also discussed. It's found that the plate is not a linear time-variant system in this case. Even if the excitation of plate is a stationary process, the output of it is still a non-stationary process.

Sun Lu,Deng Xuejun,

力学学报 , 1997,
Abstract: By using generalized Duhamel's integral and integral transform, this paper investigates random response of an infinite beam on the Kelvin viscoelastic foundation subjected to a moving load. It's found that displacement response of the beam is a non stationary random process even if the moving load is a stationary process. The follow up coordinate system is established to make the displacement became a stationary random process.
Is methane a new therapeutic gas?
Liu Wenwu,Wang Dong,Tao Hengyi,Sun XueJun
Medical Gas Research , 2012, DOI: 10.1186/2045-9912-2-25
Abstract: Background Methane is an attractive fuel. Biologically, methanogens in the colon can use carbon dioxide and hydrogen to produce methane as a by-product. It was previously considered that methane is not utilized by humans. However, in a recent study, results demonstrated that methane could exert anti-inflammatory effects in a dog small intestinal ischemia-reperfusion model. Point of view Actually, the bioactivity of methane has been investigated in gastrointestinal diseases, but the exact mechanism underlying the anti-inflammatory effects is required to be further elucidated. Methane can cross the membrane and is easy to collect due to its abundance in natural gas. Although methane is flammable, saline rich in methane can be prepared for clinical use. These seem to be good news in application of methane as a therapeutic gas. Conclusion Several problems should be resolved before its wide application in clinical practice.
Performance Study of Cooperative Diversity System over Nakagami-m Fading Channels
Jingning Wang,Xuejun Sha,Linan Sun,Zhongzhao Zhang
Information Technology Journal , 2009,
Abstract: In this study, a cooperative diversity scheme with decoded-and-forward plus amplify-and-forward is proposed by employing truncated stop-and-wait automatic repeat request for error control. All the transmission channels are assumed to exhibit Nakagami-m fading and the cross-layer performance is analyzed for the proposed scheme, such as the channel efficiency in physical layer, throughput and packet loss rate in link layer. The simulation results show that, the proposed scheme has the better cross-layer performance than other cooperative systems. By choosing a suitable partner, the proposed cooperative scheme can provide better performance than non-cooperative systems and spatial diversity gain can be obtained.
Preconditioning of Mesenchymal Stem Cells by Sevoflurane to Improve Their Therapeutic Potential
Xuejun Sun, Bo Fang, Xi Zhao, Guangwei Zhang, Hong Ma
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0090667
Abstract: Background Bone marrow mesenchymal stem cells (MSCs) have been found to produce beneficial effects on ischemia-reperfusion injury. However, most of the MSCs died when transplanted into the ischemic tissue, which severely limit their therapeutic potential. Methods Using an in vitro model of hypoxia and serum deprivation (H/SD), we investigated the hypothesis that sevoflurane preconditioning could protect MSCs against H/SD-induced apoptosis and improve their migration, proliferation, and therapeutic potential. The H/SD of MSCs and neuron-like PC12 cells were incubated in a serum-free medium and an oxygen concentration below 0.1% for 24 h. Sevoflurane preconditioning was performed through a 2-h incubation of MSCs in an airtight chamber filled with 2 vol% sevoflurane. Apoptosis of MSCs or neuron-like PC12 cells was assessed using Annexin V-FITC/propidium iodide (PI). Furthermore, the mitochondrial membrane potential was assessed using lipophilic cationic probe. The proliferation rate was evaluated through cell cycle analysis. Finally, HIF-1α, HIF-2α, VEGF and p-Akt/Akt levels were measured by western blot. Results Sevoflurane preconditioning minimized the MSCs apoptosis and loss of mitochondrial membrane potential. Furthermore, it increased the migration and expression of HIF-1α, HIF-2α, VEGF, and p-Akt/Akt, reduced by H/SD. In addition, neuron-like PC12 cells were more resistant to H/SD-induced apoptosis when they were co-cultured with sevoflurane preconditioning MSCs. Conclusion These findings suggest that sevoflurane preconditioning produces protective effects on survival and migration of MSCs against H/SD, as well as improving the therapeutic potential of MSCs. These beneficial effects might be mediated at least in part by upregulating HIF-1α, HIF-2α, VEGF, and p-Akt/Akt.
Linking Trait Differences to Community Dynamics: Evidence from Eupatorium adenophorum and Co-Occurring Native Species during a Three-Year Succession
Xianming Gao, Yujie Zhao, Xuejun Yang, Shucun Sun
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0050247
Abstract: Trait differences between invasive and native species are believed to be closely related to whether the former are successful. However, few studies have measured trait differences between invasive and native species directly under field conditions or during long term experiments. We examined the phenological pattern, plant height and biomass accumulation and allocation of Crofton weed (Eupatorium adenophorum Spreng.) and co-occurring native species in a community during a three-year succession. The phenological pattern of Crofton weed differed from that of co-occurring native species. Crofton weed had longer vegetative stage (when resources were more available), a higher biomass accumulation and a higher above/below-ground ratio compared to native species. Crofton weed was shorter than grasses and two forbs (Artemisia tangutica and Cynoglossum amabile) during its first year of growth, but was significantly taller than all other species during subsequent years. The dominance (calculated as the importance value) of Crofton weed was the highest among all other species and continually increased over time while the dominance of co-occurring native species decreased. This study provides direct field evidence that trait differences are important to plant invasion.
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