An Improved Method of Maximum Power Point Tracking Strategy for Wind Power Conversion System

CHEN Ran,CHEN Jie,CHEN Jia-wei,CHEN Zhi-hui,GONG Chun-ying,YAN Yang-guang 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

The turbine speed loop adjustment is the key link of the designing of the controller for the fixed pitch variable speed wind energy conversion systems (WECS). Because of the strong nonlinear, big inertia and mechanical damping characteristics, it’s difficult to designing the controller of the wind power systems. In this paper, a small signal model is present, and based on the analyzing; a wind turbine speed loop regulator is designed. Then, a method of tracking the peak power conversion system is proposed, which is independent of the turbine parameters and air density. At last, simulation system is built, and the results of the simulation experiments show that, the performance of the controller algorithm meet the requirements of the MPPT without wind measurement.

Combined Assessment of Serum Alpha-Synuclein and Rab35 is a Better Biomarker for Parkinson’s Disease

Hung-Li Wang,Chin-Song Lu,Tu-Hsueh Yeh,Yu-Ming Shen,Yi-Hsin Weng,Ying-Zu Huang,Rou-Shayn Chen,Yu-Chuan Liu,Yi-Chuan Cheng,Hsiu-Chen Chang,Ying-Ling Chen,Yu-Jie Chen,Yan-Wei Lin,Chia Chen Hsu,Huang-Li 대한신경과학회 2019 Journal of Clinical Neurology Vol.15 No.4

Background and Purpose It is essential to develop a reliable predictive serum biomarker for Parkinson’s disease (PD). Te accumulation of alpha-synuclein (αSyn) and up-regulated expression of Rab35 participate in the etiology of PD. Te purpose of this investigation was to determine whether the combined assessment of serum αSyn and Rab35 is a useful predictive biomarker for PD. Methods Serum levels of αSyn or Rab35 were determined in serum samples from 59 sporadic PD patients, 19 progressive supranuclear palsy (PSP) patients, 20 multiple system atrophy (MSA) patients, and 60 normal controls (NC). Receiver operating characteristics (ROC) curves were calculated to determine the diagnostic accuracy of αSyn or/and Rab35 in discriminating PD patients from NC or atypical parkinsonian patients. Results The levels of αSyn and Rab35 were increased in PD patients. The serum level of Rab35 was positively correlated with that of αSyn in PD patients. Compared to analyzing αSyn or Rab35 alone, the combined analysis of αSyn and Rab35 produced a larger area under the ROC curve and performed better in discriminating PD patients from NC, MSA patients, or PSP patients. When age was dichotomized at 55, 60, 65, or 70 years, the combined assessment of αSyn and Rab35 for classifying PD was better in the group below the cutof age than in the group above the cutof age. Conclusions Combined assessment of serum αSyn and Rab35 is a better biomarker for discriminating PD patients from NC or atypical parkinsonian patients, and is a useful predictive biomarker for younger sporadic PD patients.

Thermo-/pH-dual responsive properties of hyperbranched polyethylenimine grafted by phenylalanine

Jie Chen,Jialiang Xia,Huayu Tian,Zhaohui Tang,Chaoliang He,Xuesi Chen 대한약학회 2014 Archives of Pharmacal Research Vol.37 No.1

Novel thermo- and pH-dual responsiveamphiphilic copolymers were synthesized based on hyperbranchedpolyethylenimine (PEI) by grafting L-phenylalanine. The phenylalanine-modified PEI exhibited lowercytotoxicity than commercial PEI. These copolymersshowed the phenomena of phase transitions in response topH and temperature. The dilute copolymer solution atlower pH displayed the higher LCST. Furthermore, LCSTincreased with the increasing of phenylalanine graftingdensity. LCST of these copolymers were tunable from 7.2to 59.6 C by the degree of amidation and pH of solution. DLS and TEM experiments certified that the copolymerchains aggregated to form small size particles as increasingthe temperature above LCST. For these reasons, theobtained smart copolymers were considered to be potentialgene/drug carriers in biomedical field.

Efficacy and Safety Profile of Combining Sorafenib with Chemotherapy in Patients with HER2-Negative Advanced Breast Cancer: A Meta-analysis

Jie Chen,Chun-Xiang Tian,Miao Yu,Qing Lv,Nan-Sheng Cheng,Zu Wang,Xi Wu 한국유방암학회 2014 Journal of breast cancer Vol.17 No.1

Purpose: The aim of the study was to evaluate the efficacy andsafety of combining sorafenib with chemotherapy in patients withhuman epidermal growth factor receptor 2 (HER2)-negative advancedbreast cancer. Methods: MEDLINE, EMBASE, CochraneCentral Register of Controlled Trials, American Society for ClinicalOncology abstracts, and European Society for Medical Oncologyabstracts were searched. Randomized clinical trials that comparedthe efficacy and safety of sorafenib plus chemotherapy inpatients with HER2-negative advanced breast cancer with placeboplus chemotherapy were eligible. The endpoints were progression-free survival (PFS), overall survival (OS), time to progression(TTP), duration of response (DOR), overall response rate(ORR), clinical benefits, and adverse effects. The meta-analysiswas performed using Review Manager 5.2.6 (The Nordic CochraneCentre), and the fixed-effect model weighted by the Mantel-Haenszel method was used. When considerable heterogeneitywas found (p<0.1), further analysis (subgroup analysis, sensitivityanalysis, or random-effect model) was performed to identifythe potential cause. The results are expressed as hazard ratios orrisk ratios, with their corresponding 95% confidence intervals. Results: The final analysis included four trials comprising 844 patients. The results revealed longer PFS and TTP, and higher ORRand clinical benefit rates in patients receiving sorafenib combinedwith chemotherapy compared to those receiving chemotherapyand placebo. OS and DOR were similar in the two groups. Meanwhile,the incidence of some adverse effects, including hand-footskin reaction/hand-foot syndrome, diarrhea, rash, and hypertension,were significantly higher in the sorafenib arm. Conclusion:Sorafenib combined with chemotherapy may prolong PFS andTTP. This treatment was associated with manageable toxicities,but frequent dose interruptions and reductions were required.

Simulation of an X-ray Fresnel Zone Plate with Nonideal Factors

Chen, Jie,Fan, Quanping,Wang, Junhua,Yuan, Dengpeng,Wei, Lai,Zhang, Qiangqiang,Liao, Junsheng,Xu, Min Optical Society of Korea 2020 Current Optics and Photonics Vol.4 No.1

Fresnel zone plates have been widely used in many applications, such as x-ray telescopes, microfluorescence, and microimaging. To obtain an x-ray Fresnel zone plate, many fabrication methods, such as electron-beam etching, ion-beam etching and chemical etching, have been developed. Fresnel zone plates fabricated by these methods will inevitably lead to some nonideal factors, which have an impact on the focusing characteristics of the zone plate. In this paper, the influences of these nonideal factors on the focusing characteristics of the zone plate are studied systematically, by numerical simulations based on scalar diffraction theory. The influence of the thickness of a Fresnel zone plate on the absolute focusing efficiency is calculated for a given incident x-ray's wavelength. The diffraction efficiency and size of the focal spot are calculated for different incline angles of the groove. The simulations of zone plates without struts, with regular struts, and with random struts are carried out, to study the effects of struts on the focusing characteristics of a zone plate. When a Fresnel zone plate is used to focus an ultrashort x-ray pulse, the effect of zone-plate structure on the final pulse duration is also discussed.

Preparation and Characterization of L-Phenylalanine Modified Chitosan Resin for Aromatic Amino Acid Adsorption

Jie Zhang,Hongmei Chen,Xiaohua Zhou,Zhen Zhou,Lin Chen 한국고분자학회 2014 Macromolecular Research Vol.22 No.5

A novel L-phenylalanine modified chitosan resin (PCR) was prepared for adsorption of aromatic aminoacid from mixed amino acids solution. The structure and properties of PCR were observed by FTIR, 13C NMR, AFMand SEM. PCR was found to swell rather than dissolve in acidic mediums from its solubility and swelling behaviorexperiments. Batch adsorption experiments were performed to evaluate the adsorption capacity, selectivity and reusabilityas well as its application to the removal of L-phenylalanine and tyrosine from mixed amino acids solution. The results indicated that the maximum adsorption capacity of PCR was 309.44 mg/g in sole L-phenylalanine solutionat 25 oC. The selectivity coefficient of L-phenylalanine, tyrosine and other amino acids on PCR indicated an overallpreference for L-phenylalanine and tyrosine, which were much higher than that of non-modified chitosan resin. PCRcould be reused for ten times with about 6.26% loss. This suggests that PCR is a very promising adsorbent for theselective removal of aromatic amino acid from mixed amino acids solution.

Visual Perception Preserving Decolorization Method

Jie Chen,Xin Li,Xiuchang Zhu,Jin Wang 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.7

This paper presents a decolorization method using gradient and saliency as the maintained features in the conversion to preserve the local and global visual perception. First, we construct a linear parametric mapping function of RGB color channels. Then, we calculate the feature value of each pixel in the color image and the parameterized grayscale image, the feature value integrates the pixel gradient and region saliency. Finally, we search for the parameters which can get the minimum of the total differences between the feature values of color and grayscale images, and substitute into the linear parametric function to get the decolorization result. To enhance the efficiency of getting the best parameters, we properly relax the strict computation formulas of the gradient and saliency to construct a linear least square problem, and obtain the optimal parameters by solving optimization. Experimental results show that our method using the discrete searching strategy can maintain the contrasts meanwhile avoid the excessive enlargement of the contrasts during the color-to-gray conversion, this property guarantees the preserving of the visual perception. Our method using the linear least square strategy can reduce the computation time and frequently get the similar results with our discrete searching method.

Computer-Aided Discovery of Massonianoside B as a Novel Selective DOT1L Inhibitor

Chen, Jie,Park, Hyun-Ju AMERICAN CHEMICAL SOCIETY 2019 ACS CHEMICAL BIOLOGY Vol.14 No.5

<P>Protein methyltransferases (PMTs) are involved in numerous biological processes and have been studied as a promising target class in the field of oncology and other diseases. Disruptor of telomeric silencing 1-like (DOT1L), a histone H3 lysine 79 (H3K79) methyltransferase, plays an important role in the progressions of mixed-lineage leukemia (MLL)-rearranged leukemias and has been validated as a potential therapeutic target. Here we report the discovery and characterization of a novel DOT1L inhibitor, massonianoside B (MA), by pharmacophore-based <I>in silico</I> screening and biological studies. MA is a structurally unique natural product inhibitor of DOT1L with an IC<SUB>50</SUB> value of 399 nM. The compound displays high selectivity for DOT1L over other <I>S</I>-adenosylmethionine (SAM)-dependent PMTs. Treatment of MLL-rearranged leukemia cells with MA gives a dose-dependent reduction in cellular levels of histone lysine 79 mono- and dimethylation without affecting the methylation of other histone sites. Moreover, MA selectively inhibits proliferation and causes apoptosis in MLL-rearranged leukemia cells and downregulates the expression of MLL fusion target genes, including <I>HOXA9</I> and <I>MEIS1</I>. Molecular docking analysis revealed that MA may bind to the SAM-binding site of DOT1L. We identified MA as not only a novel DOT1L inhibitor with antileukemic activity but also a DOT1L-targeted molecular probe that may serve as a useful chemical tool for investigating the role of DOT1L in biological processes.</P> [FIG OMISSION]</BR>

Power and Promise of Ubiquitin Carboxyl-terminal Hydrolase 37 as a Target of Cancer Therapy

Chen, Yan-Jie,Ma, Yu-Shui,Fang, Ying,Wang, Yi,Fu, Da,Shen, Xi-Zhong Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.4

Ubiquitin carboxyl-terminal hydrolase 37 (UCH37, also called UCHL5), a member of the deubiquitinating enzymes, can suppress protein degradation through disassembling polyubiquitin from the distal subunit of the chain. It has been proved that UCH37 can be activated by proteasome ubiqutin chain receptor Rpn13 and incorporation into the 19S complex. UCH37, which has been reported to assist in the mental development of mice, may play an important role in oncogenesis, tumor invasion and migration. Further studies will allow a better understanding of roles in cell physiology and pathology, embryonic development and tumor formation, hopefully providing support for the idea that UCH37 may constitute a new interesting target for the development of anticancer drugs.

Flexural Properties and Electrical Conductivity of Epoxy Resin/Carbon Fiber Cloth/Metallic Powder Composites

Jie Chen,You-Jia Dong,Fan-Long Jin,박수진 한국고분자학회 2019 Macromolecular Research Vol.27 No.1

In this study, epoxy-based composites were prepared using diglycidyl ether of bisphenol A (DGEBA) as the matrix, carbon fiber cloth (CFC) as the reinforcing agent, and metallic powder as the conductive filler. The mechanical and electrical properties of DGEBA/CFC and DGEBA/CFC/metallic powder composites were investigated using several techniques. The morphology of the fracture surface was investigated using field-emission scanning electron microscopy. The flexural strength of the DGEBA/CFC composites was found to significantly increase with the addition of CFC. The electrical conductivity of the DGEBA/CFC composites significantly increased with the increasing amount of CFC and further increased after the addition of metallic powders. The electrical conductivity of the DGEBA/CFC composites significantly improved with the addition of a small amount of graphene.