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Search Results: 1 - 10 of 104388 matches for " Shuguang Zhang "
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Significant Type I and Type III Collagen Production from Human Periodontal Ligament Fibroblasts in 3D Peptide Scaffolds without Extra Growth Factors
Yoshiyuki Kumada,Shuguang Zhang
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0010305
Abstract: We here report the development of two peptide scaffolds designed for periodontal ligament fibroblasts. The scaffolds consist of one of the pure self-assembling peptide scaffolds RADA16 through direct coupling to short biologically active motifs. The motifs are 2-unit RGD binding sequence PRG (PRGDSGYRGDS) and laminin cell adhesion motif PDS (PDSGR). RGD and laminin have been previously shown to promote specific biological activities including periodontal ligament fibroblasts adhesion, proliferation and protein production. Compared to the pure RADA16 peptide scaffold, we here show that these designer peptide scaffolds significantly promote human periodontal ligament fibroblasts to proliferate and migrate into the scaffolds (for ~300 μm/two weeks). Moreover these peptide scaffolds significantly stimulated periodontal ligament fibroblasts to produce extracellular matrix proteins without using extra additional growth factors. Immunofluorescent images clearly demonstrated that the peptide scaffolds were almost completely covered with type I and type III collagens which were main protein components of periodontal ligament. Our results suggest that these designer self-assembling peptide nanofiber scaffolds may be useful for promoting wound healing and especially periodontal ligament tissue regeneration.
Production of a Bioengineered G-Protein Coupled Receptor of Human Formyl Peptide Receptor 3
Xiaoqiang Wang, Shuguang Zhang
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0023076
Abstract: G-protein coupled receptors (GPCRs) participate in a wide range of vital regulations of our physiological actions. They are also of pharmaceutical importance and have become many therapeutic targets for a number of disorders and diseases. Purified GPCR-based approaches including structural study and novel biophysical and biochemical function analyses are increasingly being used in GPCR-directed drug discovery. Before these approaches become routine, however, several hurdles need to be overcome; they include overexpression, solubilization, and purification of large quantities of functional and stable receptors on a regular basis. Here we report milligram production of a human formyl peptide receptor 3 (FPR3). FPR3 comprises a functionally distinct GPCR subfamily that is involved in leukocyte chemotaxis and activation. The bioengineered FPR3 was overexpressed in stable tetracycline-inducible mammalian cell lines (HEK293S). After a systematic detergent screening, fos-choline-14 (FC-14) was selected for subsequent solubilization and purification processes. A two-step purification method, immunoaffinity using anti-rho-tag monoclonal antibody 1D4 and gel filtration, was used to purify the receptors to near homogeneity. Immunofluorescence analysis showed that expressed FPR3 was predominantly displayed on cellular membrane. Secondary structural analysis using circular dichroism showed that the purified FPR3 receptor was correctly folded with >50% α-helix, which is similar to other known GPCR secondary structures. Our method can readily produce milligram quantities of human FPR3, which would facilitate in developing human FPR as therapeutic drug targets.
Cooperative Interference Management with MISO Beamforming
Rui Zhang,Shuguang Cui
Mathematics , 2009, DOI: 10.1109/TSP.2010.2056685
Abstract: This correspondence studies the downlink transmission in a multi-cell system, where multiple base stations (BSs) each with multiple antennas cooperatively design their respective transmit beamforming vectors to optimize the overall system performance. For simplicity, it is assumed that all mobile stations (MSs) are equipped with a single antenna each, and there is one active MS in each cell at one time. Accordingly, the system of interests can be modeled by a multiple-input single-output (MISO) interference channel (IC), termed as MISO-IC, with interference treated as noise. We propose a new method to characterize different rate-tuples for active MSs on the Pareto boundary of the achievable rate region for the MISO-IC, by exploring the relationship between the MISO-IC and the cognitive radio (CR) MISO channel. We show that each Pareto-boundary rate-tuple of the MISO-IC can be achieved in a decentralized manner when each of the BSs attains its own channel capacity subject to a certain set of interference-power constraints (also known as interference-temperature constraints in the CR system) at the other MS receivers. Furthermore, we show that this result leads to a new decentralized algorithm for implementing the multi-cell cooperative downlink beamforming.
Dynamics of high speed wheel/rail system and its modelling
ShuGuang Zhang,WeiHua Zhang,XueSong Jin
Chinese Science Bulletin , 2007, DOI: 10.1007/s11434-007-0213-1
Abstract: With the fast increasing of train speed the interactions among the train, the track, and the power catenary system become very strong. Such interactions are also strongly coupled with the action of high speed airflow due to the high speed running. Hence, the existing research methods and numerical algorithms of railway vehicle/track systems are not fully available for characterizing the transient dynamic and long-term behaviors of train/track at higher speed. The present paper reviews the existing studies on coupling dynamics of railway vehicle/track, and clarifies their advantages and disadvantages and then puts forward an innovation stratagem for high speed railway based on rolling contact of wheel/rail systems. In the innovation stratagem, a comprehensive dynamic model of wheels/rails systems is developed to simultaneously consider the track system, the train, the rolling contact of wheel/rail, the catenary/pantograph system, and the high speed airflow with the train. The motion equations of the subsystems and their coupling boundaries are given and discussed. For the reliability and safety of the high speed train in service, the long-term behavior of the structures of the train and the track is considered in the comprehensive model. Moreover, a generalized failure model, considering the structures and the materials and working in the comprehensive dynamic model of wheels/rails system, as well as the simulation system of structure failure of the high speed train/track is established. Consequently, the present studies on the dynamics of the coupled vehicle/track will be further and largely extended.
Optimal Fiscal Policy Instrument under Different Shocks  [PDF]
Shuguang Xing
Theoretical Economics Letters (TEL) , 2017, DOI: 10.4236/tel.2017.76115
Abstract: This paper constructs a New Keynesian model to study optimal tax and government spending rules and compares their welfare. The output gap, inflation and the difference between the output gap and the government spending gap all affect welfare. This paper finds that the optimal fiscal policy instruments under technical shock and cost-push shock are government spending and tax, respectively. If the policymaker is only concerned with the output gap and inflation, the optimal fiscal policy rule and actual social welfare loss will change. However, the optimal fiscal policy instruments under technical shock and cost-push shock are still government spending and tax. This paper also finds that an imperfect financial market affects social welfare but does not change the optimal fiscal policy instrument under different shocks.
Dynamics of high speed wheel/rail system and its modelling
ZHANG ShuGuang,ZHANG WeiHua,JIN XueSong,
ZHANG
,ShuGuang,ZHANG,WeiHua,JIN,XueSong

科学通报(英文版) , 2007,
Abstract: With the fast increasing of train speed the interactions among the train,the track,and the power cate-nary system become very strong. Such interactions are also strongly coupled with the action of high speed airflow due to the high speed running. Hence,the existing research methods and numerical al-gorithms of railway vehicle/track systems are not fully available for characterizing the transient dy-namic and long-term behaviors of train/track at higher speed. The present paper reviews the existing studies on coupling dynamics of railway vehicle/track,and clarifies their advantages and disadvan-tages and then puts forward an innovation stratagem for high speed railway based on rolling contact of wheel/rail systems. In the innovation stratagem,a comprehensive dynamic model of wheels/rails sys-tems is developed to simultaneously consider the track system,the train,the rolling contact of wheel/rail,the catenary/pantograph system,and the high speed airflow with the train. The motion equations of the subsystems and their coupling boundaries are given and discussed. For the reliability and safety of the high speed train in service,the long-term behavior of the structures of the train and the track is considered in the comprehensive model. Moreover,a generalized failure model,consider-ing the structures and the materials and working in the comprehensive dynamic model of wheels/rails system,as well as the simulation system of structure failure of the high speed train/track is established. Consequently,the present studies on the dynamics of the coupled vehicle/track will be further and largely extended.
Source of Sustained Voltage Difference between the Xylem of a Potted Ficus benjamina Tree and Its Soil
Christopher J. Love, Shuguang Zhang, Andreas Mershin
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0002963
Abstract: It has long been known that there is a sustained electrical potential (voltage) difference between the xylem of many plants and their surrounding soil, but the mechanism behind this voltage has remained controversial. After eliminating any extraneous capacitive or inductive couplings and ground-mediated electric current flows, we have measured sustained differences of 50–200 mV between the xylem region of a Faraday-caged, intact, potted Ficus benjamina tree and its soil, as well as between its cut branches and soils and ionic solutions standardized to various pH values. Using identical platinum electrodes, no correlation between the voltage and time of day, illumination, sap flow, electrode elevation, or ionic composition of soil was found, suggesting no direct connection to simple dissimilar-metal redox reactions or transpirational activity. Instead, a clear relationship between the voltage polarity and magnitude and the pH difference between xylem and soil was observed. We attribute these sustained voltages to a biological concentration cell likely set up by the homeostatic mechanisms of the tree. Potential applications of this finding are briefly explored.
Structural Dynamic of a Self-Assembling Peptide d-EAK16 Made of Only D-Amino Acids
Zhongli Luo, Xiaojun Zhao, Shuguang Zhang
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0002364
Abstract: We here report systematic study of structural dynamics of a 16-residue self-assembling peptide d-EAK16 made of only D-amino acids. We compare these results with its chiral counterpart L-form, l-EAK16. Circular dichroism was used to follow the structural dynamics under various temperature and pH conditions. At 25°C the d-EAK16 peptide displayed a typical beta-sheet spectrum. Upon increasing the temperature above 70°C, there was a spectrum shift as the 218 nm valley widens toward 210 nm. Above 80°C, the d-EAK16 peptide transformed into a typical alpha-helix CD spectrum without going through a detectable random-coil intermediate. When increasing the temperature from 4°C to 110°C then cooling back from 110°C to 4°C, there was a hysteresis: the secondary structure from beta-sheet to alpha-helix and then from alpha-helix to beta-sheet occurred. d-EAK16 formed an alpha-helical conformation at pH0.76 and pH12 but formed a beta-sheet at neutral pH. The effects of various pH conditions, ionic strength and denaturing agents were also noted. Since D-form peptides are resistant to natural enzyme degradation, such drastic structural changes may be exploited for fabricating molecular sensors to detect minute environmental changes. This provides insight into the behaviors of self-assembling peptides made of D-amino acids and points the way to designing new peptide materials for biomedical engineering and nanobiotechnology.
Genetics of Dothistromin Biosynthesis in the Peanut Pathogen Passalora arachidicola
Shuguang Zhang,Yanan Guo,Rosie E. Bradshaw
Toxins , 2010, DOI: 10.3390/toxins2122738
Abstract: The peanut leaf spot pathogen Passalora arachidicola (Mycosphaerella arachidis) is known to produce dothistromin, a mycotoxin related to aflatoxin. This is a feature shared with the pine needle pathogen Dothistroma septosporum (Mycosphaerella pini). Dothistromin biosynthesis in D. septosporum commences at an unusually early stage of growth in culture compared to most other fungal secondary metabolites, and the biosynthetic genes are arranged in fragmented groups, in contrast to aflatoxin gene clusters. Dothistromin biosynthetic genes were identified and studied in P. arachidicola to determine if the attributes described in D. septosporum are shared by another dothistromin-producing species within the Class Dothideomycetes. It was shown that dothistromin biosynthesis is very similar in the two species with regard to gene sequence and gene synteny. Functional complementation of D. septosporum mutants with P. arachidicola dothistromin genes was also possible. These similarities support a vertical mode of dothistromin gene transmission. P. arachidicola also produced dothistromin at an early growth stage in culture, suggesting that this type of regulation pattern may be relevant to the biological role of dothistromin.
Microbial community changes in aquifer sediment microcosm for anaerobic anthracene biodegradation under methanogenic condition

Rui Wan,Shuying Zhang,Shuguang Xie,

环境科学学报(英文版) , 2012,
Abstract: The widespread distribution of polycyclic aromatic hydrocarbons (PAHs) in groundwater has become an important environmental issue. Knowledge of microbial community changes could aid in identification of particular microorganisms that are capable of degrading PAHs in contaminated aquifers. Therefore, 16S rRNA gene clone library analysis was used to identify the archaeal and bacterial communities in an aquifer sediment microcosm used for anaerobic anthracene degradation under methanogenic conditions. A remarkable shift of the archaeal community structure occurred after anaerobic anthracene degradation, but the types of the abundant bacterial phyla did not change. However, a decrease of both archaeal and bacterial diversity was observed. Bacterial genera Bacillus, Rhodococcus and Herbaspirillum might have links with anaerobic anthracene degradation, suggesting a role of microbial consortia. This work might add some new information for understanding the mechanism of PAH degradation under methanogenic conditions.
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