Q Chen

Nanjing Medical University, Nan-ching, Jiangsu Sheng, China

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Publications (14)37.72 Total impact

  • C. Shen · X. Li · K. Tian · B. Zhang · J. Huang · Q. Chen
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    ABSTRACT: Mechanical cutting and fiber peeling are important parts in the ramie production process, and its working process is the process of interaction between rigid body (machine) and flexible body (ramie stalk). To make the developed harvester and peeling machine to meet the working requirement of high quality, efficiency and low consumption, the premise is to get mechanical characteristic parameters of crop, to have a fundamental understanding of ramie harvesting and fiber peeling mechanism. Based on this, in order to provide the mechanical parameters and theoretical basis for the research on cutting and peeling ramie, experimental analysis on the mechanical model of ramie stalk has been made in the paper. The crop object for experimental analysis was the third crop of Zhongzhu No. 1 planted in Xianning Ramie Comprehensive Experiment Station of China Agricultural Research System (Bast fiber crops), the acquisition time was on November 2nd, 2013, and the test was conducted in Nanjing Research Institute for Agricultural Mechanization, Ministry of Agriculture, during November 5th to 15th, 2013. During the experimental research process, the geometric model for ramie stalk was assumed firstly. The cross section of ramie stalk was similar to the circle, which could be respectively divided into central medulla, xylem, phloem and green husk layer. The mechanical property in the central medulla and green husk layer might be ignored. The paper abstracted and simplified the geometrical shape, and presumed that the cross section was round with certain diameter. The material, diameter and wall thickness dimension of each fraction were even. After ignoring the central medulla and green husk layer, the geometrical shape of ramie was assumed as hollow pipe, made up of different kinds of materials including xylem and phloem. Secondly, composite mechanical theory was employed to construct mechanical model of ramie stalk. Elastic parameters that should be obtained from experiment were decided according to the assumption of ramie geometrical shape and experimental equipment conditions, as well as the calculation formula of each elastic parameter. Thirdly, PC-controlled universal testing machine was applied to make mechanical test, such as tensile, compressive and bending, to ramie stalk from each direction (axial direction and radial direction) and to each part (xylem, phloem and the whole stalk), to acquire mechanical parameter data. The universal testing machine used in the experiment was WDW-10 PC-controlled electronic universal testing machine with test power range 5 kN, and the accuracy of its force sensor and displacement sensor were both maintained within ±0.1%. In tensile test, xylem, phloem and stalk samples were 20 groups of rectangle samples about 80 mm long, 6-7 mm wide, material thickness thick. Plate fixture was used, and the clamped position was covered by gauze for protection. Pre-tightening force when starting was less than 5 N, test loading rate was 5 mm/min. Then, axial tensile stress-strain curve of each sample group was obtained. In compressive test, xylem, phloem and stalk samples were 10 groups of rectangle samples about 10-11 mm long, 5-6 mm wide, material thickness thick. Compressive test briquetting was used. Thus, radial comprehensive stress-strain curve of each sample group was obtained. In bending test, xylem and stalk samples were 10 groups of samples with the length of about 120 mm. The sample cross section was tube-shape, and external and inner diameter was decided by material conditions. Sample was placed between the support and pressure head of three-point bending test fixture. Span of the support was 80 mm, pre-tightening force when starting was less than 5 N, and test loading rate was 5 mm/min. Radial bending force-deformation curve was obtained. At last, all elastic parameters of ramie stalk mechanical model were obtained with analysis of test data. The radial compressive elasticity modulus were 9.73 MPa (stalk), 10.34 MPa (xylem) and 8.03 MPa (phloem); the axis tensile elasticity modulus were 466.17 MPa (stalk), 320.92 MPa (xylem) and 2409.22 MPa (phloem); the radial bending shear modulus were 39.77 MPa (stalk), 69.02 MPa (xylem) and 33.80 MPa (phloem), the axis torsional shear modulus were 3.74 MPa (stalk), 3.98 MPa (xylem) and 3.09 MPa (phloem), the Poisson's ratios of plane XZ of each parts was assumed to 0.3, and the Poisson's ratios of plane XZ and the Poisson's ratios of plane XZ were equal, the values were <0.0269 (stalk), <0.0451 (xylem) and <0.0043 (phloem). Meanwhile, the test results of paper showed that the axial tension of ramie stalk played the load-bearing role much more in the xylem, and the adhesive force in the phloem and xylem was incapable to prevent the phloem from sliding along the surface of xylem; the measurement value of elastic parameter in the radial direction of ramie stalk was closed to the calculated value gained by calculating the elastic parameters of each fraction, and the radial direction of ramie stalk could match the characteristics of composite materials. In conclusion, the assumption of the composite model adopted in the experiment is reasonable, and experimental analysis results can be applied into subsequent related researches. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
    No preview · Article · Oct 2015
  • X Li · H Zou · M Li · Q Chen
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    ABSTRACT: The novel allele HLA-DRB1*15:115N differs from HLA-B*15:80N by a nucleotide substitution at position 227 T > A. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
    No preview · Article · Apr 2015 · Tissue Antigens
  • X Cheng · Y Yang · Z Fan · L Yu · H Bai · B Zhou · X Wu · H Xu · M Fang · A Shen · Q Chen · Y Xu
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    ABSTRACT: Malignant tumors are exemplified by excessive proliferation and aggressive migration/invasion contributing to increased mortality of cancer patients. Matrix metalloproteinase 9 (MMP9) expression is positively correlated with lung cancer malignancy. The mechanism underlying an elevated MMP9 expression is not clearly defined. We demonstrate here that the transcriptional modulator megakaryocytic leukemia 1 (MKL1) was activated by hypoxia and transforming growth factor (TGF-β), two prominent pro-malignancy factors, in cultured lung cancer cells. MKL1 levels were also increased in more invasive types of lung cancer in humans. Depletion of MKL1 in lung cancer cells attenuated migration and invasion both in vitro and in vivo. Overexpression of MKL1 potentiated the induction of MMP9 transcription by hypoxia and TGF-β, whereas MKL1 silencing diminished MMP9 expression. Of interest, MKL1 knockdown eliminated histone H3K4 methylation surrounding the MMP9 promoter. Further analyses revealed that MKL1 recruited ASH2, a component of the H3K4 methyltransferase complex, to activate MMP9 transcription. Depletion of ASH2 ameliorated cancer cell migration and invasion in an MMP9-dependent manner. Together our data indicate that MKL1 potentiates lung cancer cell migration and invasion by epigenetically activating MMP9 transcription.Oncogene advance online publication, 9 March 2015; doi:10.1038/onc.2015.14.
    No preview · Article · Mar 2015 · Oncogene
  • C Wang · J Wang · G Ou · X Ji · Z Liu · Q Chen
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    ABSTRACT: The new allele HLA-DPB1*363:01 most closely resembles DPB1*92:01, differing at a single position 191 (exon 2, codon 35). © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
    No preview · Article · Feb 2015 · Tissue Antigens
  • X. Li · H. Zou · B. Gu · Y. Zhu · Q. Chen
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    ABSTRACT: The novel allele HLA-B*37:06:02 differs from HLA-B*37:06:01 by a silent nucleotide substitution at codon 47P (CCC to CCG).
    No preview · Article · Sep 2014 · Tissue Antigens
  • G. Ou · J. Wang · C. Wang · X. Ji · Q. Chen
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    ABSTRACT: The novel allele B*15:325 shows one nucleotide difference from B*15:02:01 at codon 127 (AAC/AGC) resulting in codon 127 changes from Asn to Ser.
    No preview · Article · Sep 2014 · Tissue Antigens
  • X Li · H Zou · M Li · Y Zuo · Q Chen
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    ABSTRACT: HLA-DQB1*05:03:09 differs from HLADQB1*05:03:01 by a silent nucleotide substitution at codon 150N (AAC to AAT).
    No preview · Article · Mar 2014 · Tissue Antigens
  • J Wang · L Xia · M Luo · Q Chen
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    ABSTRACT: HLA-C*06:45 differs from HLA-C*06:02 by a single G to A substitution at position187.
    No preview · Article · Apr 2013 · Tissue Antigens
  • Y Xu · Lingling Qian · Guijuan Zong · K Ma · X Zhu · H Zhang · N Li · Q Yang · H Bai · J Ben · X Li · Q Chen
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    ABSTRACT: Class A scavenger receptor (SR-A) is primarily expressed in microglia/macrophages and plays an important role in immune responses. However, whether SR-A can influence microglia/macrophage polarization in cerebral ischemic injury is not known. To this end we monitored the phenotypic alteration of microglia/macrophages in an animal model of cerebral ischemia injury. SR-A was up-regulated in mouse brains 24h after permanent occlusion of middle cerebral artery (MCAO). SR-A-deficient mice displayed reduced infarct size and improved neurological function compared with wild-type mice littermate controls. Furthermore, a decrease in inflammatory F4/80(+)CD11b(+)CD45(high)CD11c(+) microglia/macrophages and attenuated nuclear factor-kappaB (NF-κB) activation was found in ischemic brains in the SR-A null mice. This was accompanied by alleviation of classically activated M1 macrophage markers and preservation of alternatively activated M2 macrophage markers. These data suggest that SR-A contributes to cerebral ischemic injury by pivoting the phenotype of microglia/macrophages to a skewed M1 polarization.
    No preview · Article · May 2012 · Neuroscience
  • S Zhang · J Wang · M Luo · X Li · Q Chen
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    ABSTRACT: MICA*064N is similar to MICA*027 except for one nucleotide mutation at position 801(G>A), resulting in a premature stop codon in exon 4.
    No preview · Article · Apr 2012 · Tissue Antigens
  • S Zhang · J Wang · M Luo · X Li · Q Chen
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    ABSTRACT: The MICA*010:02 allele differs from MICA*010:01 allele by a synonymous mutation in exon 5 at position 933(T > C).
    No preview · Article · Nov 2011 · Tissue Antigens
  • Source
    S S Zhu · Y Ren · M Zhang · J Q Cao · Q Yang · XY Li · H Bai · L Jiang · Q Jiang · Z G He · Q Chen
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    ABSTRACT: We aimed to evaluate the effect of the mutant Wld(S) (slow Wallerian degeneration; also known as Wld) gene in experimental diabetes on early experimental peripheral diabetic neuropathy and diabetic retinopathy. The experiments were performed in four groups of mice: wild-type (WT), streptozotocin (STZ)-induced diabetic WT, C57BL/Wld(S) and STZ-induced diabetic C57BL/Wld(S). In each group, intraperitoneal glucose and insulin tolerance tests were performed; blood glucose, glycated haemoglobin and serum insulin were monitored. These mice were also subjected to the following behavioural tests: grasping test, hot-plate test and von Frey aesthesiometer test. For some animals, sciatic-tibial motor nerve conduction velocity, tail sensory nerve conduction velocity and eye pattern electroretinogram were measured. At the end of the experiments, islets were isolated to detect glucose-stimulated insulin secretion, ATP content and extent of apoptosis. The NAD/NADH ratio in islets and retinas was evaluated. Surviving retinal ganglion cells were estimated by immunohistochemistry. We found that the Wld(S) gene is expressed in islets and protects beta cells against multiple low doses of STZ by increasing the NAD/NADH ratio, maintaining the ATP concentration, and reducing apoptosis. Consistently, significantly higher insulin concentrations, lower blood glucose concentrations, and better glucose tolerance were observed in Wld(S) mice compared with WT mice after STZ treatment. Furthermore, Wld(S) alleviated abnormal sensory responses, nerve conduction, retina dysfunction and reduction of surviving retinal ganglion cells in STZ-induced diabetic models. We provide the first evidence that expression of the Wld(S) gene decreases beta cell destruction and preserves islet function in STZ-induced diabetes, thus revealing a novel protective strategy for diabetic models.
    Full-text · Article · Sep 2011 · Diabetologia
  • Q Chen · H Zou · X H Xu · M Luo · Y Q Zuo · Y H Chen · X H Chen · X L Chen · Z Q Yao · N Song · J Zeng · X Y Mi · S X Sun · J X Wang · T M Zhao
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    ABSTRACT: The human leukocyte antigen (HLA)-B*5516 allele differs from the B*5502 by a single 97 T --> C substitution (His to Tyr at position 33) in exon 2. The B*1313 allele results from 419 T --> A and 420 A --> C substitutions, encoding a Leu to Tyr substitution at 140 in exon 2 of the B*1301 allele. The B*9512 allele differs from B*1502 by a single 360 G --> C substitution (Gln to His at 120) in exon 3. The DRB1*1457 allele appears to be a hybrid molecule generated by recombination between the DRB1*13 and DRB1*14 alleles. The serological equivalents of these new alleles are HLA-B22, -B13, -B15, and DR13, respectively. Family studies detected two rare haplotypes: A*11, B*9512, DRB1*14 and A*24, B*52, Cw*07, DRB1*1457, DRB3*020201, DQB1*050301. The gene frequencies of these alleles in the Chinese population are less than 0.0001.
    No preview · Article · Oct 2006 · Tissue Antigens
  • X. Qin · J. Cao · H. Bai · Q. Yang · Q. Chen

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Publication Stats

60 Citations
37.72 Total Impact Points

Institutions

  • 2011-2015
    • Nanjing Medical University
      • • Department of Pathophysiology
      • • Atherosclerosis Research Center
      Nan-ching, Jiangsu Sheng, China
  • 2006-2012
    • Chinese Academy of Medical Sciences
      Peping, Beijing, China