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Search Results: 1 - 10 of 43130 matches for " Zhong-Zheng;Duan "
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Effects of female diet and age on offspring sex ratio of the solitary parasitoid Pachycrepoideus vindemmiae (Rondani) (Hymenoptera, Pteromalidae)
Hu, Hao-Yuan;Chen, Zhong-Zheng;Duan, Bi-Sheng;Zheng, Jin-Tu;Zhang, Tong-Xin;
Revista Brasileira de Entomologia , 2012, DOI: 10.1590/S0085-56262012005000028
Abstract: effects of female diet and age on offspring sex ratio of the solitary parasitoid pachycrepoideus vindemmiae (rondani) (hymenoptera, pteromalidae). theories predict that females of parasitoid wasps would adjust the offspring sex ratio to environmental conditions in the oviposition patch, but the diet and age of females would also affect the sex ratio adjustment. our focus was to test the effects of female diet and age on offspring sex ratio of the solitary parasitoid wasp, pachycrepoideus vindemmiae (rondani, 1875). our results showed that females fed with honey had significantly less female biased offspring sex ratio than those fed only with water. offspring sex ratio (male percentage) decreased with female age or female longevity at the beginning of oviposition but increased at the end. there should be a sperm limitation in p. vindemmiae females at the end of oviposition, and a higher frequency of unfertilized eggs were laid then. females also laid more unfertilized eggs at the beginning of oviposition, which would be necessary to insure the mating among offspring. male offspring developed faster and emerged earlier, which would also reduce the risk of virginity in offspring with female-biased sex ratio.
Electronic theory of the mechanism of corrosion of Pb-Mg-Al alloy
Pb-Mg-Al合金腐蚀机理的电子理论研究

Duan Yong-Hu,Sun Yong,He Jian-Hong,Peng Ming-Jun,Guo Zhong-Zheng,
段永华
,孙勇,何建洪,彭明军,郭中正

物理学报 , 2012,
Abstract: The cohesive energies, Fermi energies and local density of states (LDOS) are calculated by the first-principles based on pseudopotential plane wave method in this paper to investigate the physical nature of corrosion of Pb-Mg-Al alloy. The mechanism of electrochemical corrosion is analyzed according to the calculated electronic structure parameters. The results show that the stable phase in Pb-Mg-Al alloy is Mg17Al12>Mg2Pb>Mg. The Fermi energy (Ef) values of these phases with Ef(Mg)>Ef(Mg2Pb)>Ef (Mg17Al12) indicate that Mg is most likely to lose electrons while Mg17Al12 is difficult. LDOS result reveals that Mg and Mg2Pb phases are unstable compared with Mg17Al12 in the same external conditions, they are more likely to lose electrons and easier to corrod. The difference in Fermi energy between different phases in Pb-Mg-Al alloy forms the electrodynamic force of the electrochemical corrosion, which leads electrons to flow from the Mg and Mg2Pb phases with higher Fermi energy to Mg17Al12 phase with lower Fermi energy, further to corrode in Pb-Mg-Al alloy.
Improved Statistical Analysis for Array CGH-Based DNA Copy Number Aberrations
Hongmei Jiang,Zhong-Zheng Zhu,Yue Yu,Simon Lin
Cancer Informatics , 2011,
Abstract:
Improved Statistical Analysis for Array CGH-Based DNA Copy Number Aberrations
Hongmei Jiang, Zhong-Zheng Zhu, Yue Yu, Simon Lin and Lifang Hou
Cancer Informatics , 2012, DOI: 10.4137/CIN.S8019
Abstract: Array-based comparative genomic hybridization (aCGH) allows measuring DNA copy number at the whole genome scale. In cancer studies, one may be interested in identifying DNA copy number aberrations (CNAs) associated with certain clinicopathological characteristics such as cancer metastasis. We proposed to define test regions based on copy number pattern profiles across multiple samples, using either smoothed log2-ratio or discrete data of copy number gain/loss calls. Association test performed on the refined test regions instead of the probes has improved power due to reduced number of tests. We also compared three types of measurement of copy number levels, normalized log2-ratio, smoothed log2-ratio, and copy number gain or loss calls in statistical hypothesis testing. The relative strengths and weaknesses of the proposed method were demonstrated using both simulation studies and real data analysis of a liver cancer study.
Airborne particulate matter and mitochondrial damage: a cross-sectional study
Lifang Hou, Zhong-Zheng Zhu, Xiao Zhang, Francesco Nordio, Matteo Bonzini, Joel Schwartz, Mirjam Hoxha, Laura Dioni, Barbara Marinelli, Valeria Pegoraro, Pietro Apostoli, Pier Bertazzi, Andrea Baccarelli
Environmental Health , 2010, DOI: 10.1186/1476-069x-9-48
Abstract: In 63 male healthy steel workers from Brescia, Italy, studied between April and May 2006, we evaluated whether exposure to PM was associated with increased mitochondrial DNA copy number (MtDNAcn), an established marker of mitochondria damage and malfunctioning. Relative MtDNAcn (RMtDNAcn) was determined by real-time PCR in blood DNA obtained on the 1st (time 1) and 4th day (time 2) of the same work week. Individual exposures to PM10, PM1, coarse particles (PM10-PM1) and airborne metal components of PM10 (chromium, lead, arsenic, nickel, manganese) were estimated based on measurements in the 11 work areas and time spent by the study subjects in each area.RMtDNAcn was higher on the 4th day (mean = 1.31; 95%CI = 1.22 to 1.40) than on the 1st day of the work week (mean = 1.09; 95%CI = 1.00 to 1.17). PM exposure was positively associated with RMtDNAcn on either the 4th (PM10: β = 0.06, 95%CI = -0.06 to 0.17; PM1: β = 0.08, 95%CI = -0.08 to 0.23; coarse: β = 0.06, 95%CI = -0.06 to 0.17) or the 1st day (PM10: β = 0.18, 95%CI = 0.09 to 0.26; PM1: β = 0.23, 95%CI = 0.11 to 0.35; coarse: β = 0.17, 95%CI = 0.09 to 0.26). Metal concentrations were not associated with RMtDNAcn.PM exposure is associated with damaged mitochondria, as reflected in increased MtDNAcn. Damaged mitochondria may intensify oxidative-stress production and effects.Ambient and occupational exposure to Particulate Matter (PM) has been linked with increased hospitalization and mortality from cardiovascular disease, respiratory disease, and lung cancer [1-8]. In-vitro and in-vivo studies have identified generation of reactive oxygen species (ROS) and increased oxidative stress as a primary biological process that may contribute to produce such a variety of diverse health effects [9-14]. Epidemiologic [1,15] and in-vivo studies [16-18] suggest that both PM mass and PM metal components contribute to ROS generation. Mitochondria are the major intracellular source and primary target of ROS, which are generated und
Primary spectrum pyrometry based on radiation measurement within a finite solid angle
基于有限立体角测量的谱色测温法

Xin Cheng-Yun,Cheng Xiao-Fang,Zhang Zhong-Zheng,
辛成运
,程晓舫,张忠政

物理学报 , 2013,
Abstract: The true surface temperature for an object can be determined by measuring emitted radiation. Primary spectrum pyrometry should be generally carried out by radiation measurement within an infinitesimal solid angle or within a finite solid angle in the case of diffuse emission, so that the radiation thermometry equations become a closed system for temperature and other undetermined parameters. The radiation thermometry equation with linear emissivity model is obtained, which can be used to measure the temperature of the object with non-diffuse emission within a finite solid angle. This equation is universal in radiation measurement, based on which equations for primary spectrum pyrometry are deduced. These equations are also universal in radiation measurement, in which the emissivity scales under different measurement conditions are limited to the same range, but have different physical meanings.
Research on eco-economic functional regionalization of important water supply region of the Yellow River in Gannan area
甘南黄河重要水源补给区生态经济功能区区划研究

XUE Zhong-Zheng,LI Wen-Long,XU Dan-Dan,WANG Xun,YANG Zhan-Shan,
薛中正
,李文龙,徐丹丹,王 迅,杨占山

中国生态农业学报 , 2010,
Abstract: Using TM image and statistical yearbook data of the Yellow River source in Gannan area, Gansu Province, along with vegetation coverage, water conservation, land use pattern, population density and agricultural and animal products as ecological factors, the eco-economic functional regionalization of important water supply region of the Yellow River in Gannan was conducted. An analytical hierarchy process was developed to weigh ecological factors in study area. Based on the weights of the ecological factors, the Yellow River source region in Gannan was classified into town construction and eco-agricultural economy zone, hydro-ecological recharge zone of the Yellow River, eco-agricultural economy zone of the Tao River, livestock product supply and ecological tourism zone, and livestock product supply zone of Maqu. The ecological characteristics and problems in eco-economic development of different zones were discussed through analysis on the internal connection among different zones. The developmental directions, ways and countermeasures were also advanced. The findings of the research could provide guidelines for protecting, constructing and developing the study area.
A novel mutation in NF1 gene in a Chinese patient with Legius syndrome like café au lait spots  [PDF]
Dongdong Zheng, Xiaohong Duan
Case Reports in Clinical Medicine (CRCM) , 2013, DOI: 10.4236/crcm.2013.22038
Abstract:

Neurofibromatosis type I (NF1) (OMIM, 162200) and Legius syndrome (OMIM, 611431) both have multiple café au lait spots. It is a challenge to differentiate the two diseases. Here we report a Legius syndrome-like patient who finally was identified as NF1 with a novel mutation in NF1 exon1 (c.55G > T). The mutation caused a substitution of a glutamic acid (GAG) with a terminator codon (TAG). For those patients with only multiple café au lait macules, axillary and inguinal freckling, but without any other clinical signs in NF1 and Legius syndrome, a gene testing is necessary to give a final diagnose. We suggested to use “Neurofibromatosis type 1like syndrome” to describe those patients just like our patient reported here.

Asymptotic Analysis of Multi-Antenna Cognitive Radio Systems Using Extreme Value Theory
Ruifeng Duan,Zhong Zheng,Riku J?ntti,Jyri H?m?l?inen
Mathematics , 2015,
Abstract: We consider a spectrum-sharing cognitive radio system with antenna selection applied at the secondary transmitter (ST). Based on the extreme value theory, we deduce a simple and accurate expression for the asymptotic distribution of the signal to interference plus noise ratio at the secondary receiver. Using this result, the asymptotic mean capacity and the outage capacity for the secondary user (SU) are derived. The obtained asymptotic capacities approach the exact results as the number of transmit antennas $N$ increases. Results indicate that the rate of the SU scales as $\log(N)$ when the transmit power of the ST is limited by the maximum allowable interference level, while rate scales as $\log(\log(N))$ if ST is limited by the maximum transmit power.
Optical Properties of the Coupling Interface for Planar Optical Waveguides  [PDF]
Yu Zheng, Ji-An Duan
Optics and Photonics Journal (OPJ) , 2011, DOI: 10.4236/opj.2011.13018
Abstract: Planar optical waveguides are the key elements in a modern, high-speed optical network. An important problem facing the optical fiber communication system, specifically planar optical waveguides, is coupling. The current study presents a coupling model for planar optical waveguides and optical fibers. The various effects of the optical properties of the coupling interface were analyzed by the scalar finite difference beam propagation method, including the thickness, with or without the matching refractive index of the interface adhesive. The findings can serve as a guide for planar optical waveguide packaging.
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