Estimates of linkage disequilibrium and effective population sizes in Chinese Merino (Xinjiang type) sheep by genome-wide SNPs

Shudong Liu,Sangang He,Lei Chen,Wenrong Li,Jiang Di,Mingjun Liu 한국유전학회 2017 Genes & Genomics Vol.39 No.7

Knowledge of linkage disequilibrium (LD) is important for effective genome-wide association studies and accurate genomic prediction. Chinese Merino (Xinjiang type) is well-known fine wool sheep breed. However, the extent of LD across the genome remains unexplored. In this study, we calculated autosomal LD based on genomewide SNPs of 635 Chinese Merino (Xinjiang type) sheep by Illumina Ovine SNP50 BeadChip. A moderate level of LD (r2 ≥ 0.25) across the whole genome was observed at short distances of 0–10 kb. Further, the ancestral effective population size (Ne) was analyzed by extent of LD and found that Ne increased with the increase of generations and declined rapidly within the most recent 50 generations, which is consistent with the history of Chinese Merino sheep breeding, initiated in 1971. We also noted that even when the effective population size was estimated across different single chromosomes, Ne only ranged from 140.36 to 183.33 at five generations in the past, exhibiting a rapid decrease compared with that at ten generations in the past. These results indicated that the genetic diversity in Chinese Merino sheep recently decreased and proper protective measures should be taken to maintain the diversity. Our datasets provided essential genetic information to track molecular variations which potentially contribute to phenotypic variation in Chinese Merino sheep.

Decision diagram based methods and reliability analysis for k-out-of-n: G systems

Shumin Li,Shudong Sun,Shubin Si,Shuai Zhang,Hongyan Dui 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.10

Binary k-out-of-n systems are commonly used reliability models in engineering practice. Many authors have extended the concept ofk-out-of-n system to multi-state k-out-of-n systems. This paper proposes a binary decision diagram (BDD) based approach for binary kout-of-n: G system and a multi-state multi-valued decision diagram (MMDD) based approach for multi-state k-out-of-n: G system. BDDand MMDD have been extensively used for representing and manipulating logic functions in many areas, including reliability modelingand analysis. In this paper, patterns of BDD/MMDD for binary/multi-state k-out-of-n: G system are summarized and proved, a two-stepalgorithmic process is proposed for modeling the BDD/MMDD and three case studies are implemented to demonstrate the presentedmethods. Complexity analysis shows that the presented method is more computationally efficient than the traditional algorithms for kout-of- n: G system.

Modeling dynamic behavior of MDOF systems with multiple bilinear springs

Yali Ma,Shudong Yu,Delun Wang 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.9

A computational scheme is presented in this paper to simulate dynamical behavior of multiple degrees of freedom (MDOF) systems with multiple bilinear springs. In the proposed scheme, a bilinear spring is modeled using by two parallel springs - a primary spring and a secondary spring. The primary spring is an ordinary linear spring having identical stiffness in tension and compression, and is active for tension and compression. The secondary spring, whose stiffness characterizes the bilinearity, is active only during compression. It is employed in connection with the Newmark integration method and the linear complementarity problem (LCP) formulation to obtain time-domain responses of dynamical systems with bilinear springs due to initial disturbances and harmonic excitations. The scheme described in this paper is effective in dealing with the sudden transition from tension to compression and vice versa simultaneously for all bilinear springs. Numerical results for bilinear oscillators with finite bilinearity ratios and impact oscillators with an infinite bilinearity ratio show that the proposed bilinear spring model is accurate, generic and valid for bilinearity ratios ranging from zero to infinity. Orderly and chaotic behavior of viscously damped 3-DOF system under harmonic excitation is studied for a wide range of excitation frequencies and bilinear ratios to demonstrate the effectiveness and applicability of the proposed model for MDOF bilinear systems.

Vibrational behavior of MDOF oscillators subjected to multiple contact constraints

Mo Fadaee,Shudong Yu 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.4

Vibrational behavior of harmonically excited MDOF oscillators subjected to multiple contact constraints is investigated in this paper using the combination of the Newmark integration scheme and the Linear complementarity problem (LCP) formulation. An oscillator with gap-activated non-smooth spring constraints exhibits various complex behavior such as sub-harmonic resonances, bifurcations and chaos, which are effectively predicted using the proposed method. Numerical results were obtained and presented for SDOF and 5-DOF systems with frequency and stiffness parameters varying in wide ranges to validate the Newmark-LCP method and to demonstrate its effectiveness in dealing with MDOF systems with multiple contact constraints.

NOx Storage-Reduction over Pt/Mg-Al-O Catalysts with Different Mg/Al Atomic Ratios

Guangwen Chen,Hao Cheng,Shudong Wang,Diyong Wu,Yin Zhang,Henqiang Li 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.3

A series of Pt/Mg-Al-O catalysts with different Mg/Al atomic ratios were prepared. The NOx storagecapacities of these catalysts were measured by isothermal storage at 350oC. It was found that the NOx storage capacityincreased with increasing Mg/Al atomic ratios. The catalytic behaviors of Pt/Mg-Al-O and Pt/MgO were studied withstorage-reduction cycles at 400oC. Under oxidizing conditions, NOx concentration in the outlet gas gradually increasedwith time, which indicated the catalysts could store NOx effectively. After a switch from oxidizing conditions toreducing conditions, NOx desorption peak emerged immediately due to the incomplete reduction of stored NOx, whichlowered the total NOx conversion. With increasing Mg/Al atomic ratio in the catalysts, NOx conversion increases. Pt/MgO has the highest NOx conversion because of its best activity in the reduction of NOx by C3H6. It seems that withan increasing amount of MgO in the catalysts, the self-poisoning of Pt-sites by adsorbed species during the reactionof NOx with C3H6 may be inhibited effectively.

Palladium supported on carbon nanofiber coated monoliths for three-phase nitrobenzene hydrogenation: Influence of reduction temperature and oxidation pre-treatment

Baolei Du,Hongjiu Su,Shudong Wang 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1

Carbon nanofiber (CNF) coated monoliths with a homogeneous and consistent layer were prepared bycatalytic decomposition of ethane on Ni particles, and the CNF coated monolith supports were oxidizedusing different agents to get different oxidation degrees. The as-prepared catalysts were characterized bySEM, TG, Raman spectra, FT-IR, TPD, TPR, CO pulsar and TEM, while the behavior of Pd supported on CNFcoated monoliths were tested by liquid phase of nitrobenzene hydrogenation in a continuous flowreactor. For comparison Pd/Al2O3/cordierite was also prepared. It was found that the reductiontemperature controlled Pd dispersion, which in turn was responsible for the catalytic activity. A goodlinear relationship between nitrobenzene conversion and Pd dispersion was observed. Furthermore, Pd/CNF/cordierite showed higher nitrobenzene conversion compared with Pd/Al2O3/cordierite, indicatingCNF was a superior support. The aniline selectivity was related to the amount of surface oxygen groups(SOCs) formed during the oxidation pre-treatment. SOCs, especially carboxylic acid groups, increased asthe degree of oxidation deepened, and more amounts of SOCs on CNF surface were responsible for thelower aniline selectivity.

Rectifying resistance switching behaviors of SnO2 microsphere films modulated by top electrodes

Rongchun Yuan,Weiwei Xia,Mengxue Xu,Zhilei Miao,Shudong Wu,Xiuyun Zhang,Junhui He,Qiang Wang 한국물리학회 2020 Current Applied Physics Vol.20 No.3

Based on the bipolar resistive switching (RS) characteristics of SnO2 films, we have fabricated a new prototypical device with sandwiched structure of Metal/SnO2/fluorine-doped tin oxide (FTO). The SnO2 microspheres film was grown on FTO glass by template-free hydrothermal synthesis, which was evaporated with various commonly used electrodes such as aluminium (Al), silver (Ag), and gold (Au), respectively. Typical self-rectifying resistance switching behaviors were observed for the RS devices with Al and Au electrodes. However, no obvious rectifying resistance switching behavior was observed for the RS device with Ag electrode. Above results were interpreted by considering the different interface barriers between SnO2 and top metal electrodes. Our current studies pave the ways for modulating the self-rectifying resistance switching properties of resistive memory devices by choosing suitable metal electrodes.

Comparative Genomics Profiling of Clinical Isolates of Helicobacter pylori in Chinese Populations Using DNA Microarray

Yue-Hua Han,Wen-Zhong Liu,Yao-Zhou Shi,Li-Qiong Lu,Shudong Xiao,Qing-Hua Zhang,Guo-Ping Zhao 한국미생물학회 2007 The journal of microbiology Vol.45 No.1

In order to search for specific genotypes related to this unique phenotype, we used whole genomic DNA microarray to characterize the genomic diversity of Helicobacter pylori (H. pylori) strains isolated from clinical patients in China.The open reading frame (ORF) fragments on our microarray were generated by PCR using gene-specific primers. Genomic DNA of H. pylori 26695 and J99 were used as templates. Thirty-four H. pylori isolates were obtained from patients in Shanghai. Results were judged based on ln(x) transformed and normalized Cy3/Cy5 ratios. Our microarray included 1882 DNA fragments corresponding to 1636 ORFs of both sequenced H. pylori strains. Cluster analysis, revealed two diverse regions in the H. pylori genome that were not present in other isolates. Among the 1636 genes, 1091 (66.7%) were common to all H. pylori strains, representing the functional core of the genome. Most of the genes found in the H. pylori functional core were responsible for metabolism, cellular processes, transcription and biosynthesis of amino acids, functions that are essential to H. pylori’s growth and colonization in its host. In contrast, 522(31.9%) genes were strain-specific genes that were missing from at least one strain of H. pylori. Strainspecific genes primarily included restriction modification system components, transposase genes, hypothetical proteins and outer membrane proteins. These strain-specific genes may aid the bacteria under specific circumstances during their long-term infection in genetically diverse hosts. Our results suggest 34 H. pylori clinical strains have extensive genomic diversity. Core genes and strain-specific genes both play essential roles in H. pylori propagation and pathogenesis. Our microarray experiment may help select relatively significant genes for further research on the pathogenicity of H. pylori and development of a vaccine for H. pylori.

Improved Resistance Switching Characteristics of BiFeO3 Thin Film by Increasing the Annealing Temperature

Zhilei Miao,Wei Wang,Rongchun Yuan,Jun Zhu,Shudong Wu,Haitao Chen,Xianghua Zeng,Qiang Wang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.09

We have fabricated BiFeO3 thin film deposited on Pt/Ti/SiO2/Si substrates by the chemical solution deposition method. The effects of annealing temperature on the thin film structure, resistance switching (RS) properties, conduction mechanisms are investigated. It exhibits improved RS window with high ON/OFF ratio ( ~10 4) for the sample annealed at 650 ℃. XPS characterization indicates that cation ratio of Fe2+/Fe3+ is increased with increasing annealing temperature. Crystal lattice distortion generated by Fe2+ cations, along with oxygen vacancies, commonly contribute to opening the RS window and the increment of conductive filaments. The film's conduction mechanisms under different annealing temperatures are fully discussed. The RS properties of this system can be effectively improved by increasing the annealing temperature, which is crucial prerequisite for future applications of BFO-based thin film device in resistance random access memory.

Mesoporous silica with monodispersed pores synthesized from the controlled self-assembly of silica nanoparticles

Min Su,Hongjiu Su,Baolei Du,Xiaotong Li,Gaoyuan Ren,Shudong Wang 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.5

Silica nanoparticles with different sizes (ranging from 10 nm to 104 nm) and size distributions were synthesized by semi-batch and semi-batch/batch methods of the Stöber process. Then the amorphous silica with different surface areas (ranging from 30m2/g to 400m2/g) and pores (ranging from 3 nm to 33 nm) were obtained by various aging treatments and drying methods of the synthesized colloidal silica sol. The aging treatment resulted in the monodispersed pore distribution and decreased BET surface area of silica. The high-humidity drying method led to the mesoporous silica with uniform pores and decreased small pores. As the silica was obtained by the arrangement of silica nanoparticles, the pore diameter and pore distribution of mesoporous silica were directly related to the size and distribution of nanoparticles. Furthermore, this study offered a new thought for the synthesis of other mesoporous materials with uniform pore distributions.