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Search Results: 1 - 10 of 62596 matches for " Xiao Sun "
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Collision Detection and the Design of Fair and Stable MAC Scheme for Wireless Ad Hoc Networks  [PDF]
Yongkang Xiao, Rong Xiao, Bo Sun
Communications and Network (CN) , 2013, DOI: 10.4236/cn.2013.53B2065
Abstract: Fairness and stability guarantee among TCP flows is very stubborn in wireless ad hoc networks. There is not a MAC protocol that can fulfill this acquirement until now. In this paper, we firstly reveal the in-depth causes of the severe TCP unfairness and instability problems in IEEE 802.11-based multihop networks. Then we utilize the collision detection mechanism of the IEEE 802.11 protocol which is often ignored by most of the people to design a novel collision detection mechanism-based MAC (CDMB-MAC) scheme to solve the short-term and long-term fairness and stability issues while providing a good aggregate throughput in many topologies.
Constrain-based analysis of gene deletion on the metabolic flux redistribution of Saccharomyces Cerevisiae  [PDF]
Zi-Xiang Xu, Xiao Sun
Journal of Biomedical Science and Engineering (JBiSE) , 2008, DOI: 10.4236/jbise.2008.12020
Abstract: Based on the gene-protein-reaction (GPR) model of S. cerevisiae_iND750 and the method of constraint-based analysis, we first calculated the metabolic flux distribution of S. cere-visiae_iND750. Then we calculated the deletion impact of 438 calculable genes, one by one, on the metabolic flux redistribution of S. cere-visiae_iND750. Next we analyzed the correlation between v (describing deletion impact of one gene) and d (connection degree of one gene) and the correlation between v and Vgene (flux sum controlled by one gene), and found that both of them were not of linear relation. Furthermore, we sought out 38 important genes that most greatly affected the metabolic flux distribution, and determined their functional subsystems. We also found that many of these key genes were related to many but not several subsystems. Because the in silico model of S. cere-visiae_iND750 has been tested by many ex-periments, thus is credible, we can conclude that the result we obtained has biological sig-nificance.
Mitochondria: transportation, distribution and function during spermiogenesis  [PDF]
Xiao Sun, Wan-Xi Yang
Advances in Bioscience and Biotechnology (ABB) , 2010, DOI: 10.4236/abb.2010.12014
Abstract: Spermiogenesis is a dynamic process which includes organelle reorganization and new structure formation. The morphology and distribution of the mitochondria in germ cells change to accommodate the cellular requirement. Multiple molecular motors and related proteins participate in carrying and anchoring mitochondria to the midpiece during spermiogenesis and this process is regulated precisely. Energetic metabolism provides energy for cellular activity and influences sperm survival and motility directly. Ubiquitination of mitochondria takes place during spermiogenesis, which has been implicated in sperm quality control and mitochondrial inheritance. In light of the essential roles of mitochondria in energy production, calcium homeostasis and apoptosis, mitochondria dysfunction cause severe human diseases, such as male infertility. The present study paves a way for a more detailed exploration of the biology of mitochondria during spermiogenesis.
Chemical composition, antioxidant and antibacterial activities of essential oil from Korean Citrus unshiu peel  [PDF]
Xiao Nan Yang, Sun Chul Kang
Journal of Agricultural Chemistry and Environment (JACEN) , 2013, DOI: 10.4236/jacen.2013.23007
Abstract: The chemical composition, antioxidant and antibacterial activities of essential oil from peel of Citrus unshiuwhich cultivated in South Korea were investigated. Eight compounds were identified as l-limonene (88.11%), γ-terpinene (4.66%), cyclohexane, 2,4-diisopropenyl-1-methyl-1-vinyl (1.82%), diethyl phthalate (1.02%), β-linalool (0.97%), β-myrcene (0.91%), α-farnesene (0.91%) and o-cymene (0.85%)
by GC-MS. The SC50values of this essential oil on DPPH and superoxide anion were 0.21 and 0.22% (v/v), respectively. The results of zone of inhibition, MIC, MBC and cell viability demonstrated the essential oil of-Citrus unshiupeel displayed antibacterial effect against B. cereus KCTC 14042, B. subtilis ATCC 6633 and S. aureusATCC 6538. The release of cell material and potassium ion from the B. subtilis ATCC 6633 cells treated with essential oil was further investigated. SEM observation also revealed the damaging effect of the essential oil on the morphology of B. subtilisATCC 6633 cells at minimum inhibitory concentration.

Roles of BMP6/7 in Actin Dynamics in Amyloid β-Induced Neurotoxicity  [PDF]
Lin Sun, Yingjie Zhang, Shifu Xiao
Psychology (PSYCH) , 2014, DOI: 10.4236/psych.2014.57082

Actin dynamics plays an important role in many physiological functions such as long-term potentiation, neurotransmission, regulatory proteins translocation, ATP cycle, etc. When amyloid β (Aβ)-induced neurotoxicity occurs, the imbalance of actin dynamics leads to dystrophy of dendrites, which is characteristic pathology in Alzheimer’s disease (AD). Transient and persistent Aβ neurotoxicity provokes distinct manifestations of actin dynamics and causes opposing effects in AD. It has been shown that bone morphogenetic protein 6/7 (BMP6/7) protects neuronal morphology against Aβ-induced neurotoxicity, and can directly bind to LIM kinase1 (LIMK1), being one part of the upstream regulatory pathway of actin dynamics. This review aims to discuss a potential mechanism of BMPs underlying maintainance of cytoskeletal stabilization in neurite.

An Adaptive Momentum CMA Blind Equalization Based on Error Energy  [PDF]
Ying Xiao, Yuhua Dong, Jinyu Sun
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2017, DOI: 10.4236/ijcns.2017.105B033
To solve the problem of large steady state residual error of momentum constant modulus algorithm (CMA) blind equalization, a momentum CMA blind equalization controlled by energy steady state was proposed. The energy of the equalizer weights is estimated during the updating process. According to the adaptive filtering theory, the energy of the equalizer weights reaches to the steady state after the algorithm is converged, and then the momentum can be set to 0 when the energy change rate is less than the threshold, which can avoid the additional gradient noise caused by momentum and further improve the convergence precision of the algorithm. The proposed algorithm takes advantage of momentum to quicken the convergence rate and to avoid the local minimum in the cost function to some extent; meanwhile, it has the same convergence precision with CMA. Computer simulation results show that, compared with CMA, momentum CMA (MCMA) and adaptive momentum CMA (AMCMA) blind equalization, the proposed algorithm has the fastest convergence rate and the same steady state residual error with CMA.
Meta-analysis of several gene lists for distinct types of cancer: A simple way to reveal common prognostic markers
Xinan Yang, Xiao Sun
BMC Bioinformatics , 2007, DOI: 10.1186/1471-2105-8-118
Abstract: We describe a set of significantly similar ordered gene lists, representing outcome comparisons for distinct types of cancer. This kind of similarity could improve the diagnostic accuracies of individual studies when SOGL is incorporated into the support vector machine algorithm. In particular, we investigate the similarities among three ordered gene lists pertaining to mesothelioma survival, prostate recurrence and glioma survival. The similarity-driving genes are related to the outcomes of patients with lung cancer with a hazard ratio of 4.47 (p = 0.035). Many of these genes are involved in breakdown of EMC proteins regulating angiogenesis, and may be used for further research on prognostic markers and molecular targets of gene therapy for cancers.The proposed method and its application show the potential of such meta-analyses in clinical studies of gene expression profiles.Changes in gene expression levels could reflect clinically distinct conditions. Genome-wide perspectives of gene expression can now be obtained, and these can be combined with other currently-used criteria to identify predictors of clinical outcome for specific cancers [1-7]. Also, distinct gene expression profiles can reportedly determine molecular treatment responses, e.g. in cancer [8]. Thus it is possible to discover biomarkers from gene expression profiles that help to predict outcomes, and this emphasizes the need in biomedical research to combine results from similar experiments in order to identify diagnostic or prognostic disease markers.Much recent research has confirmed that microarray results are comparable among different laboratories, especially when a common platform and a set of procedures are used [9-13]. Integrative analysis that evaluates cancer transcriptome data in the context of data from other sources has received attention recently (reviewed by Rhodes and Chinnaiyan [14]). An important emerging argument concerns the uniformity of cancer metastases as well as the evolutio
Original studies on anti-tumor and immunological effect of extracts from Thymus quinquecostatus Celak in mice
SUN Zhen-Xiao
Zhong Xi Yi Jie He Xue Bao , 2003,
Abstract: Objective: To study the anti-tumor and immunological effect of extracts from Thymus quinquecostatus Celak on mice transplanted S180 tumor cells. Methods: Different doses of volatile oil and alcohol extracted substances from Thymus quinquecostatus Celak were given to mice bearing S180 tumor for 9 days. Tumor inhibition rates and coefficients of spleen and thymus were determined. Results: Tumor inhibition rates of the groups with alcohol extracts (40 g crude drug·kg-1·d-1 and 20 g crude drug·kg-1·d-1) were 51.5% (P<0.01) and 36.4% (P<0.05) respectively, and those of the groups with volatile oil (40 g crude drug·kg-1·d-1 and 20 g crude drug·kg-1·d-1) were both 39.4% (P<0.05). Conclusion: The extracts from Thymus quinquecostatus Celak have anti-tumor activities. The coefficient of spleen in group with alcohol extracts (40 g crude drug·kg-1·d-1) was close to normal value, and its coefficient of thymus was between that of the negative control group and the group with cyclophosphamide (0.02 g·kg-1·d-1). The anti-tumor activity of the alcohol extracts was significantly higher than that of the control group and the tumor inhibition rate was depending on drug concentration. Depending on index of immunity, the extracts from Thymus quinquecostatus Celak may have some influences on immunity.
A review of studies on active agents and pharmacology of Thyme
Zhen-xiao SUN
Zhong Xi Yi Jie He Xue Bao , 2009,
Anti-tumor effect of ethanol extracts from Thymus quinquecostatus Celak on human leukemia cell line
SUN Zhen-Xiao
Zhong Xi Yi Jie He Xue Bao , 2005,
Abstract: Objective: To screen the anti-tumor fraction of ethanol extracts from Thymus quinquecostatus Celak and investigate its anti-tumor effect on human leukemia cell line. Methods: Ethyl acetate, n-butanol and acetone fractions were separated from the ethanol extracts of wild Thymus quinquecostatus Celak. Growth inhibiting effects of these extracts on human leukemia cell lines K562 and HL-60 were determined by live cell counting and cell growth curve analysis. The possible anti-tumor mechanism was studied by morphological analysis with norcantharidin as a positive control. Results: Ethyl acetate fraction could significantly inhibit the proliferations of K562 and HL-60 cells, and the inhibiting effect depended on the concentration of ethyl acetate fraction. Ethyl acetate fraction could induce apoptosis of K562 and HL-60 cells. The n-butanol and acetone fractions had no significant inhibiting effect on K562 and HL-60 cells. Conclusion: Ethyl acetate fraction is the major anti-tumor fraction in ethanol extracts from Thymus quinquecostatus Celak.
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