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Search Results: 1 - 10 of 78708 matches for " Jianming Chen "
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Modeling and Simulation of Adaptive Surface Tracked Vehicle Based on RecurDyn  [PDF]
Wei Chen, Jianming Zhan, Hang Zhou
Open Journal of Modelling and Simulation (OJMSi) , 2013, DOI: 10.4236/ojmsi.2013.14007
Abstract: In order to improve the adaptability of the tracked vehicle in the road and strengthen the grip of the tracked vehicle, a track surface adaptive mechanism was provided. In theory, it has been proved practically. Meanwhile, RecurDyn, which is a multi-body kinematics software, was used to build a multi-body soft hybrid model, based on structure, elasticity, linear damping adaptive tracked vehicle; meanwhile the model was used to carry on the kinematics simulation. Through the comparison between simulated motion trail and that of traditional motion trail, this paper analyzed the deviation of the motion trail and also simulated the motion trail of the warped surface so as to test the adaptive ability of the mechanism. According to the results, the adaptive mechanism was equipped with great surface adaptability. It can also adapt to the complex warped surface, and enjoy a damping effect.
Recommending a Book with a Chapter Reviewing Innovative Approaches of Solar Cell Research  [PDF]
Jianming Li
Natural Resources (NR) , 2013, DOI: 10.4236/nr.2013.41A015
Abstract:

This article is a brief description of some innovative approaches presented in Chapter 6 of a book entitled “Solar Cell Research Progress”. One approach is a novel superficial modification technique which offers a new opportunity to fabricate low cost solar cells by using silicon materials with the lowest possible purity. The other approach is a V-shaped module (VSM) technique which enables an obvious increase of the efficiencies for silicon solar cells.

Ordering of Unicyclic Graphs with Perfect Matchings by Minimal Matching Energies  [PDF]
Jianming Zhu
Open Journal of Discrete Mathematics (OJDM) , 2019, DOI: 10.4236/ojdm.2019.91004
Abstract: In 2012, Gutman and Wagner proposed the concept of the matching energy of a graph and pointed out that its chemical applications can go back to the 1970s. The matching energy of a graph is defined as the sum of the absolute values of the zeros of its matching polynomial. Let u and v be the non-isolated vertices of the graphs G and H with the same order, respectively. Let wi?be a non-isolated vertex of graph Gi?where i=1, 2, …, k. We use Gu(k)?(respectively, Hv(k)) to denote the graph which is the coalescence of G (respectively, H
Uniqueness of Entire Functions Sharing Polynomials with Their Derivatives
Jianming Qi,Feng Lü,Ang Chen
Abstract and Applied Analysis , 2009, DOI: 10.1155/2009/847690
Abstract: We use the theory of normal families to prove the following. Let 1()=1
Data Gathering Schedule for Minimal Aggregation Time in Wireless Sensor Networks
Xujin Chen,Xiaodong Hu,Jianming Zhu
International Journal of Distributed Sensor Networks , 2009, DOI: 10.1080/15501320701585527
Abstract: In this article we consider the MAT problem with collision-free transmission where a sensor can not receive any data if more than one sensors within its transmission range send data at the same time. We first prove that the MAT problem is NP-hard even if all sensors are deployed on a grid. We then propose a (∆ - 1)-approximation algorithms for the MAT problem, where ∆ is the maximum number of sensors within the transmission range of any sensor. By exploiting the geometric nature of wireless sensor networks, we obtain some better theoretical results for some special cases. We also simulate the proposed algorithm. The numerical results show that our algorithm has much better performance in practice than the theoretically proved guarantees and outperforms other existing algorithms.
Productive Parvovirus B19 Infection of Primary Human Erythroid Progenitor Cells at Hypoxia Is Regulated by STAT5A and MEK Signaling but not HIFα
Aaron Yun Chen,Steve Kleiboeker,Jianming Qiu
PLOS Pathogens , 2011, DOI: 10.1371/journal.ppat.1002088
Abstract: Human parvovirus B19 (B19V) causes a variety of human diseases. Disease outcomes of bone marrow failure in patients with high turnover of red blood cells and immunocompromised conditions, and fetal hydrops in pregnant women are resulted from the targeting and destruction of specifically erythroid progenitors of the human bone marrow by B19V. Although the ex vivo expanded erythroid progenitor cells recently used for studies of B19V infection are highly permissive, they produce progeny viruses inefficiently. In the current study, we aimed to identify the mechanism that underlies productive B19V infection of erythroid progenitor cells cultured in a physiologically relevant environment. Here, we demonstrate an effective reverse genetic system of B19V, and that B19V infection of ex vivo expanded erythroid progenitor cells at 1% O2 (hypoxia) produces progeny viruses continuously and efficiently at a level of approximately 10 times higher than that seen in the context of normoxia. With regard to mechanism, we show that hypoxia promotes replication of the B19V genome within the nucleus, and that this is independent of the canonical PHD/HIFα pathway, but dependent on STAT5A and MEK/ERK signaling. We further show that simultaneous upregulation of STAT5A signaling and down-regulation of MEK/ERK signaling boosts the level of B19V infection in erythroid progenitor cells under normoxia to that in cells under hypoxia. We conclude that B19V infection of ex vivo expanded erythroid progenitor cells at hypoxia closely mimics native infection of erythroid progenitors in human bone marrow, maintains erythroid progenitors at a stage conducive to efficient production of progeny viruses, and is regulated by the STAT5A and MEK/ERK pathways.
Evaluation of Major Factors Affecting Spatial Resolution of Gamma-Rays Camera  [PDF]
Hongwei Xie, Jianhua Zhang, Jinchuan Chen, Faqiang Zhang, Linbo Li, Jianming Qi, Yanyun Chu
Journal of Analytical Sciences, Methods and Instrumentation (JASMI) , 2013, DOI: 10.4236/jasmi.2013.34029
Abstract:

The spatial resolution of the gamma-rays camera was measured on a60Co gamma-rays source with edge method. The gamma-rays camera is consisting with rays-fluorescence convertor, optical imaging system, MCP image intensifier, CCD camera, electronic control system and other devices, and is mainly used in the image diagnostics of the intense pulse radiation sources [1]. Due to the relatively big quantum detective efficiency (DQE) and quantum gain of the gamma-rays, etc., the experimental data were processed by averaging multiple images and fitting curves. According to the experimental results, the spatial resolution MTF (modulation transfer function) at the 10% intensity was about 2lp/mm. Meanwhile, because of the relatively big dispersion effects of the fluorescence transmissions in the scintillator and the optical imaging system, the maximal single-noise ratio (SNR) of the camera was found to be about 5:1. In addition, the spatial resolution of the camera was measured with pulse X-rays with 0.3MeV in average energy and exclusion of the effects of secondary electrons from consideration. Accordingly, the spatial resolution MTF at the 10% intensity was about 5lp/mm. This could be an additional evidence to verify the effects of secondary electrons induced by the 1.25MeV gamma-rays in the scintillator upon the spatial resolution. Based on our analysis, the dispersion sizes of the secondary electrons in the scintillator are about 0.4mm-0.6mm. Comparatively, as indicated by the detailed analysis of the spatial resolutions of the MCP image intensifier and CCD devices, both of them have little effect on the spatial resolution of the gamma-rays camera that could be well neglected.

One Case about the Diagnosis and Treatment of Right-Sided Infective Endocarditis without Any Inducement  [PDF]
Shengsen Chen, Kangkang Yu, Qingxia Ling, Chong Huang, Jianming Zheng, Qi Cheng, Mengqi Zhu, Ning Li, Mingquan Chen
Case Reports in Clinical Medicine (CRCM) , 2014, DOI: 10.4236/crcm.2014.312134
Abstract: We present a case of Staphylococcus aurous tricuspid valve endocarditis without any risk factors (intravenous drug users, with pacemaker or central venous lines and with congenital heart disease). Transthoracic echocardiography, as first line examination, showed the vegetations on tricuspid valve. In our case, the diagnosis and treatment of right-sided infective endocarditis without any inducement were extremely difficult. Therefore, once a patient comes out with fever, the blood culture remains positive for gram-positive bacterium, and the infectious location still unknown, then the infective endocarditis should be considered. In addition, surgical measure is also an important therapy for right-sided infective endocarditis.
Chipmunk Parvovirus Is Distinct from Members in the Genus Erythrovirus of the Family Parvoviridae
Zhaojun Chen,Aaron Yun Chen,Fang Cheng,Jianming Qiu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0015113
Abstract: The transcription profile of chipmunk parvovirus (ChpPV), a tentative member of the genus Erythrovirus in the subfamily Parvovirinae of the family Parvoviridae, was characterized by transfecting a nearly full-length genome. We found that it is unique from the profiles of human parvovirus B19 and simian parvovirus, the members in the genus Erythrovirus so far characterized, in that the small RNA transcripts were not processed for encoding small non-structural proteins. However, like the large non-structural protein NS1 of the human parvovirus B19, the ChpPV NS1 is a potent inducer of apoptosis. Further phylogenetic analysis of ChpPV with other parvoviruses in the subfamily Parvovirinae indicates that ChpPV is distinct from the members in genus Erythrovirus. Thus, we conclude that ChpPV may represent a new genus in the family Parvoviridae.
Use of an EZ-Tn5-Based Random Mutagenesis System to Identify a Novel Toxin Regulatory Locus in Clostridium perfringens Strain 13
Jorge E. Vidal, Jianming Chen, Jihong Li, Bruce A. McClane
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0006232
Abstract: Background Although useful for probing bacterial pathogenesis and physiology, current random mutagenesis systems suffer limitations for studying the toxin-producing bacterium Clostridium perfringens. Methodology/Principal Findings An EZ-Tn5-based random mutagenesis approach was developed for use in C. perfringens. This mutagenesis system identified a new regulatory locus controlling toxin production by strain 13, a C. perfringens type A strain. The novel locus, encoding proteins with homology to the AgrB and AgrD components of the Agr quorum sensing system of Staphylococcus aureus and two hypothetical proteins, was found to regulate early production of both alpha toxin and perfringolysin O (PFO) by strain 13. PFO production by the strain 13 ΔagrB mutant could be restored by genetic complementation or by physical complementation, i.e. by co-culture of the strain 13 ΔagrB mutant with a pfoA mutant of either strain 13 or C. perfringens type C CN3685. A similar AgrB- and AgrD-encoding locus is identifiable in all sequenced C. perfringens strains, including type B, C, D, and E isolates, suggesting this regulatory locus contributes to toxin regulation by most C. perfringens strains. In strain 13, the agrB and agrD genes were found to be co-transcribed in an operon with two upstream genes encoding hypothetical proteins. Conclusions/Significance The new Tn5-based random mutagenesis system developed in this study is more efficient and random than previously reported C. perfringens random mutagenesis approaches. It allowed identification of a novel C. perfringens toxin regulatory locus with homology to the Agr system of S. aureus and which functions as expected of an Agr-like quorum sensing system. Since previous studies have shown that alpha toxin and perfringolysin O are responsible for strain 13-induced clostridial myonecrosis in the mouse model, the new agr regulatory locus may have importance for strain 13 virulence.
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