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Organization process of the hierarchical structures in microbially synthesized polyhydroxyalkanoates
Jun Xu,Bao-Hua Guo,Qiong Wu,Jin-Chun Chen,Guo-Qiang Chen,Jian-Jun Zhou,Yong Jiang,Lin Li 한국물리학회 2007 Current Applied Physics Vol.7 No.s1
cess of the high-order structures in biomaterials. Real-time Fourier transform infrared spectroscopy and optical microscopy demon-strated that helical segments formed along with the spherulite growth. Atomic force microscopy revealed the details of growth,twisting and branching of lamellar crystals. Cooperative packing of these twisting lamellae led to regular banded spherulites observedunder polarized light microscopy. Real-time observation on the crystallization process provided richer information than the characterization of the final structures; consequently, it provides deeper insight into the organization mechanism of the hierarchical structures.
Research on the Inter-harmonics Equivalent Impedance of Series Hybrid Active Power Filter
Jian-gong, Zhang,Jian-ben, Liu,Shao-jun, Dai,Qiao-fu, Chen,Jun-jia, He The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.5
In the series hybrid active power filter (SHAPF) with magnetic flux compensation (MFC), the system current oscillate in the experimental results when adding the same phase harmonic current command in current control block. This condition endangers the security of the SHAPF. Taking the digit period average arithmetic as example, this paper explains the inter-harmonics current oscillation in the experiment. The conclusion is that the SHAPF is unstable to the inter-harmonics current in theory. Limited by the capacity of the inverter, the system current and the inverter output current do not increase to infinite. At last, some methods are proposed to solve this problem. From the practical viewpoint, the voltage feed-forward control is easy to achieve. It can suppress the current oscillation problems, and also improve the filtering effect. The feasibility of the methods is validated by both the emulation and experiment results.
Structural dynamic optimization with probability constraints of frequency and mode
Chen, Jian-Jun,Che, Jian-Wen,Sun, Huai-An,Ma, Hong-Bo,Cui, Ming-Tao Techno-Press 2002 Structural Engineering and Mechanics, An Int'l Jou Vol.13 No.5
The structural dynamic optimization problem based on probability is studied. Considering the randomness of structural physical parameters and the given constraint values, we develop a dynamic optimization mathematical model of engineering structures with the probability constraints of frequency, forbidden frequency domain and the vibration mode. The sensitivity of structural dynamic characteristics based on probability is derived. Two examples illustrate that the optimization model and the method applied are rational and efficient.
Chen, Qing-Wei,Zhang, Xiao-Mei,Zhou, Jian-Nong,Zhou, Xin,Ma, Guo-Jian,Zhu, Ming,Zhang, Yuan-Ying,Yu, Jun,Feng, Ji-Feng,Chen, Sen-Qing Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.12
Background: : Familial adenomatous polyposis (FAP) is an autosomal dominant inherited disease mainly caused by mutations of the adenomatous polyposis coli (APC) gene with almost complete penetrance. These colorectal polyps are precancerous lesions that will inevitable develop into colorectal cancer at the median age of 40-year old if total proctocolectomy is not performed. So identification of APC germline mutations has great implications for genetic counseling and management of FAP patients. In this study, we screened APC germline mutations in Chinese FAP patients, in order to find novel mutations and the APC gene germline mutation characteristics of Chinese FAP patients. Materials and Methods: The FAP patients were diagnosed by clinical manifestations, family histories, endoscope and biopsy. Then patients peripheral blood samples were collected, afterwards, genomic DNA was extracted. The mutation analysis of the APC gene was conducted by direct polymerase chain reaction (PCR) sequencing for micromutations and multiplex ligation-dependent probe amplification (MLPA) for large duplications and/or deletions. Results: We found 6 micromutations out of 14 FAP pedigrees, while there were no large duplications and/or deletions found. These germline mutations are c.5432C>T(p. Ser1811Leu), two c.3926_3930delAAAAG (p.Glu1309AspfsX4), c.3921_3924delAAAA (p.Ile1307MetfsX13), c3184_3187delCAAA(p.Gln1061AspfsX59) and c4127_4126delAT (p.Tyr1376LysfsX9), respectively, and all deletion mutations resulted in a premature stop codon. At the same time, we found c.3921_3924delAAAA and two c.3926_3930delAAAAG are located in AAAAG short tandem repeats, c3184_3187delCAAA is located in the CAAA interrupted direct repeats, and c4127_4128 del AT is located in the 5'-CCTGAACA-3', 3'-ACAAGTCC-5 palindromes (inverted repeats) of the APC gene. Furthermore, deletion mutations are mostly located at condon 1309. Conclusions: Though there were no novel mutations found as the pathogenic gene of FAP in this study, we found nucleotide sequence containing short tandem repeats and palindromes (inverted repeats), especially the 5 bp base deletion at codon 1309, are mutations in high incidence area in APC gene,.
Research on the Inter-harmonics Equivalent Impedance of Series Hybrid Active Power Filter
Zhang Jian-gong,Liu Jian-ben,Dai Shao-jun,Chen Qiao-fu,He Jun-jia 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.5
In the series hybrid active power filter (SHAPF) with magnetic flux compensation (MFC), the system current oscillate in the experimental results when adding the same phase harmonic current command in current control block. This condition endangers the security of the SHAPF. Taking the digit period average arithmetic as example, this paper explains the inter-harmonics current oscillation in the experiment. The conclusion is that the SHAPF is unstable to the inter-harmonics current in theory. Limited by the capacity of the inverter, the system current and the inverter output current do not increase to infinite. At last, some methods are proposed to solve this problem. From the practical viewpoint, the voltage feed-forward control is easy to achieve. It can suppress the current oscillation problems, and also improve the filtering effect. The feasibility of the methods is validated by both the emulation and experiment results.
Macrophage-secreted Exosomes Delivering miRNA-21 Inhibitor can Regulate BGC-823 Cell Proliferation
Wang, Jian-Jun,Wang, Ze-You,Chen, Rui,Xiong, Jing,Yao, Yong-Liang,Wu, Jian-Hong,Li, Guang-Xin Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.10
Exosomes, membranous nanovesicles, naturally carry bio-macromolecules or miRNA and play impoetant roles in tumor pathogenesis. Here, we showed that macrophages cell-derived exosomes can function as vehicles to deliver exogenous miR-21 inhibitor into BGC-823 gastric cancer cells. Exosomes loaded with miR-21inhibitor significantly increased miR-21 levels in BGC-823, but miR-21inhibitor loaded in exosomes exerted an opposite effect. miRNA transfected with exosomes had less cellular toxicity to host cells compared to conventional transfection methods. The miR-21inhibitor loaded exosomes promoted the migration ability and reduced apoptosis of BGC-823 gastric cancer cells. These observations indicate that miR-21 acts as a tumor promoter by targeting the PDCD4 gene and preventing apoptosis of gastric cancer cells through inhibition of PDCD4 expression. Furthermore, exosome -mediated miR-21 inhibitor delivery resulted in functionally more efficient inhibition and less cellular toxicity compared to conventional transfection methods. Similar approaches could be useful in modification of target biomolecules in vitro and in vivo. These findings contribute to our understanding of the functions of miR-21 and exosomes as a carrier for therapy of gastric cancer.
A Continuous Abnormal Speech Detection Method Based on Time Domain features Weighted
He Jun,Ji-chen Yang,Qing-hua Zhang,Guo-xi Sun,Jian-bing Xiong 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.12
In this brief, a novel pathological continuous speech detection method based on time domain features weighted. First, different optimal threshold for time domain features, including zero crossing ratio, short-time energy and autocorrelation, are obtained from training speech data. Second, a difference evaluation technique is proposed, and with it, the difference of the same time domain feature selected from testing speech data and training speech data were obtained. Finally, to distinguish a given speech well, a novel weighting method based on difference evaluation for each kinds of time domain is employed, respectively. Experiments were conducted on the pathological speech database to prove the power and effectiveness of the proposed method. Results obtained shown that this method outperforms other early proposed time domain feature method, creating a more reliable technique for pathological continuous speech detection.
Bulk Synthesis of Fe3Al Intermetallic Compound Nanoparticles by Flow-Levitation Method
Shan-Jun Chen,Song Li,Yang-En Wang,Hui Zeng,Yong-Jian Tang,Wei-Guo Sun,Yan Chen 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.1
Metallic nanopowders have an increasing application in magnetic materials, catalysts and chemical and metallic industries. In this research, a novel bulk synthesis method for preparing high pure intermetallic Fe3Al nanoparticles was developed by flow-levitation (FL) method. The Fe and Al vapors ascending from the high-temperature levitated droplet were condensed by cryogenic argon gas under atmospheric pressure. X-ray diffraction (XRD) and selected-area electron diffraction (SAED) were used to identify and characterize the prepared nanopowders exhibiting a Fe3Al phase. Measurement of transmission electron microscopy (TEM) indicated that the Fe3Al particles are nearly spherical, and the particle size of the compound ranges from 10 nm to 200 nm in diameter. The chemical composition of the nanoparticles were determined with energy dispersive spectrometer. The magnetic properties of the nanopowder indicate that Fe3Al intermetallic compound is a soft magnet at room temperature, with coercivity of 24.2 Oe and saturation magnetization of 173.2 emu/g. The production rate of Fe3Al nanoparticles was estimated to be about 4 g/h in a continuous manner, by using the FL method. This method as great potential in mass production of Fe3Al nanoparticles.