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Search Results: 1 - 10 of 25793 matches for " Shujun Cheng "
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Combining Genome Wide Association Studies and Differential Gene Expression Data Analyses Identifies Candidate Genes Affecting Mastitis Caused by Two Different Pathogens in the Dairy Cow  [PDF]
Xing Chen, Zhangrui Cheng, Shujun Zhang, Dirk Werling, D. Claire Wathes
Open Journal of Animal Sciences (OJAS) , 2015, DOI: 10.4236/ojas.2015.54040
Abstract: Mastitis is a costly disease which hampers the dairy industry. Inflammation of the mammary gland is commonly caused by bacterial infection, mainly Escherichia coli, Streptococcus uberis and Staphylococcus aureus. As more bacteria become multi-drug resistant, one potential approach to reduce the disease incidence rate is to breed selectively for the most appropriate and potentially protective innate immune response. The genetic contribution to effective disease resistance is, however, difficult to identify due to the complex interactions that occur. In the present study two published datasets were searched for common differentially expressed genes (DEGs) with similar changes in expression in mammary tissue following intra-mammary challenge with either E. coli or S. uberis. Additionally, the results of seven published genome-wide association studies (GWAS) on different dairy cow populations were used to compile a list of SNPs associated with somatic cell count. All genes located within 2 Mbp of significant SNPs were retrieved from the Ensembl database, based on the UMD3.1 assembly. A final list of 48 candidate genes with a role in the innate immune response identified from both the DEG and GWAS studies was further analyzed using Ingenuity Pathway Analysis. The main signalling pathways highlighted in the response of the bovine mammary gland to both bacterial infections were 1) granulocyte adhesion and diapedesis, 2) ephrin receptor signalling, 3) RhoA signalling and 4) LPS/IL1 mediated inhibition of RXR function. These pathways comprised a network regulating the activity of leukocytes, especially neutrophils, during mammary gland inflammation. The timely and properly controlled movement of leukocytes to infection loci seems particularly important in achieving a good balance between pathogen elimination and excessive tissue damage. These results suggest that polymorphisms in key genes in these pathways such as SELP, SELL, BCAR1, ACTR3, CXCL2, CXCL6, CXCL8 and FABP may influence the ability of dairy cows to resist mastitis.
Association between Single Nucleotide Polymorphism in RelA with Somatic Cell Count and Longevity Supports Importance of NF-κB Signalling in Cattle Health  [PDF]
Xing Chen, Shujun Zhang, Zhangrui Cheng, Geoffrey E. Pollott, D. Claire Wathes
Open Journal of Animal Sciences (OJAS) , 2019, DOI: 10.4236/ojas.2019.91005
Abstract: Mastitis reduces milk production and causes culling. The NF-κB transcription factor RelA plays a central regulatory role in innate immunity. This study used a candidate gene approach to investigate associations between the synonymous C/G SNP rs48035703 in RELA with somatic cell count (SCC) and survival time. Blood samples were collected from 337 Holstein-Friesian heifers on 19 farms and genotyped by PCR-restriction fragment length polymorphism. Animals were monitored from 6 months until 2340 d of age. Pedigree, milk production and disease records were obtained. Genotype frequencies were CC 0.63, CG 0.30 and GG 0.06. The C allele had a favourable additive effect on survival: average longevities from birth were CC, 1872 d; CG, 1745 d and GG 1596 d (P < 0.003). Log transformed first lactation somatic cell count (SCC)data showed a significant association with this SNP using an allele substitution model (mean residuals ± SD: GG 0.30 ± 1.263; CG 0.22 ± 0.994, CC -0.04 ± 0.803, P < 0.05). More CC cows than expected were classified as intermediate and fewer as mastitic (30.4% v 45.9%) with respect to SCC class when categorised as 0 (unaffected), 1 (intermediate) and 2 (mastitic), whereas for CG heterozygotes fewer were intermediate and more were mastitic (12.1% v 60.3%) (p = 0.05). RELA rs48035703 CC genotype cows were therefore less likely to experience a high SCC and survived longer. These results support a role for RelA in combating mammary gland infection and warrant further studies in additional populations.
Fast and Convenient Synthesis of Amine-Terminated Polylactide as a Macroinitiator for -Benzyloxycarbonyl-L-Lysine-N-Carboxyanhydrides
Mingjie Ju,Feirong Gong,Shujun Cheng,Yun Gao
International Journal of Polymer Science , 2011, DOI: 10.1155/2011/381076
Abstract: Amine-terminated poly (L-lactide) (NH2-PLLA) with various chain lengths were successfully synthesized by sequential tert-butyl-N-(3-hydroxypropyl) carbamate initiated bulk ring-opening polymerization (ROP) of L-lactide (L-LA) in the presence of Stannous(II) 2-ethylhexanoate (Sn(Oct)2) and deprotection of the N-tert-butoxycarbonyl (Boc) group at the end of the polymer chain. The polymers obtained were characterized by FT-IR, 1H NMR, and GPC method. NH2-PLLA thus prepared was used to initiate the polymerization of ω-benzyloxycarbonyl-L-lysine-N-carboxyanhydride (Lys (Z)-NCA), and the result confirmed the high nucleophilicity of the terminal amine group. This method was not only suitable for the preparation of low molecular weight NH2-PLLA, but also quite efficient in the synthesis of high molecular weight samples. 1. Introduction During the last few years, aliphatic polyesters based on hydroxyalkanoic acid, such as polylactides (PLLA), polyglycolide (PGA), poly (caprolactone) (PCL), and their copolymers have become the most important biopolymers because of their biodegradability and good biocompatibility for pharmaceutical and biomedical applications. However, the scope of further application of PLLA is limited for the lacking of highly reactive groups as triggers of chemical reaction, and the surface of PLLA is very hydrophobic [1]. Chemical modification, especially end functionalization, is an important method to expand the applications area of these polymers [2]. The end-functionalized polymers are also important intermediates which can react at the end of the chain with other molecules containing reactive groups such as acid chlorides, sulfonyl chlorides, acid anhydrides, and activated esters for the synthesis of novel polymeric materials [3, 4]. NH2-PLLA can be used to conjugate with lactose to form a new bioabsorbable material which shows high biodegradability and gives a microphase separation structure [1]. Especially, they were investigated as a macroinitiator for the ring-opening polymerization (ROP) of amino acid N-carboxyanhydrides (NCAs) to prepare a block copolymer containing polypeptide segments which showed quite different properties from other polymers [5–14]. The synthesis of NH2-PLLA was based on a method first reported by Gotsche et al. in 1995 [5]. The main idea of his point was capping the hydroxyl end group of PLLA with BOC-L-Phe which containing a protective amino group using N,N′-dicyclohexylcarbodiimide (DCC) as the condensing agent. However, conversion of the hydroxyl group into an N-protected amino acid ester with the acylation
Hyaluronan Immobilized Polyurethane as a Blood Contacting Material
Feirong Gong,Yue Lu,Hui Guo,Shujun Cheng,Yun Gao
International Journal of Polymer Science , 2010, DOI: 10.1155/2010/807935
Abstract: Hyaluronan (hyaluronic acid, HA) was immobilized onto the surface of amino-functionalized polyurethane films with the goal of obtaining a novel kind of biomaterial which had the potential in blood-contacting applications. The amino-functionalized polyurethane was prepared by synthesized acidic polyurethane whose pendant carboxyl groups were treated with an excess amount of 1,3-diaminopropane in the presence of N,N-carbonyldiimidazole (CDI). Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy (RS), scanning electron microscopy (SEM), and water contact angle measurement were used to confirm the surface changes at each step of treatment, both in morphologies and chemical compositions. APTT and PT results showed that HA immobilization could prolong the blood coagulation time, thus HA-immobilized polyurethane (PU-HA) exhibited improved blood compatibility. Cytotoxicity analysis showed that the PU-HA films synthesized in this study were cytocompatible and could support human vein endothelial cells (HUVECs) adhesion and proliferation. 1. Introduction Thermoplastic polyurethanes (PU) have been widely used for various biomedical applications due to their excellent mechanical properties and proper blood compatibility. Recently, much effort has been focused on polyurethanes as blood-contacting materials, such as cardiovascular biomaterials, hemodialysis blood line sets, central venous catheters (CVC), and IV bags [1, 2]. However, surface-induced thrombosis, protein fouling, and cytocompatibility have become the major drawbacks that hinder their further biomedical applications as blood-contacting materials. Surface modification is an effective approach to improve the blood compatibility, the size, shape, and mechanical properties of the original material maintained. Many studies have been performed on producing a blood-compatible surface by tailoring with poly(ethylene glycol) (PEG) [3, 4], heparin [5, 6], heparin-like [7–9], phospholipid polymer [10–13], hirudin [14], sulfobetaine [15, 16], and so on. Although many hydrogels or hydrophilized surfaces exhibit good blood compatibility, most of these are not truly antithrombogenic but only antithromboadhesive [17] as they curtail or inhibit platelets and blood cell adhesion rather than prolong the coagulation time. Hyaluronan (HA), a linear biopolymer naturally abundant in mammalian tissues, is composed of repeating units of N-acetyl-D-glucosamine and D-glucuronic acid, linked by -(1,4) and -(1,3) glycosidic junctions [18]. HA has been identified as a nontoxic,
Growth, structure and upconversion mechanisms of Ba2ErCl7 crystal
Jianru Han,Guangyong Zhou,Shujun Zhang,Zhenxiang Cheng,Huanchu Chen
Chinese Science Bulletin , 2000, DOI: 10.1007/BF02884974
Abstract: The methods to grow a novel upconversion crystal Ba2ErCl7 are reported in this note. Ba2ErCl7 material was synthesized with Er2O3, BaCl2·2H2O and NH4Cl by using a so-called “direct synthesis method”. High quality Ba2ErCl7 single crystals with size up to 4 mm×8 mm×15 mm were grown by using the Czochralski and the Bridgman methods. Intense yellow-green luminescence was detected when the crystal was pumped by an 803 laser diode (LD). Transmittance spectrum was measured by using HITACH U-3500 spectrophotometer at room temperature for the first time, in which one can see that the transmittance is high in the range from 350 to 1 600 nm and the cut-off wavelength of the crystal was 230 nm. The upconversion mechanisms were discussed.
Growth, structure and upconversion mechanisms of Ba2ErCl7 crystal
Human neuronal tau promoting the melting temperature of DNA

HAN Jianru,ZHOU Guangyong,ZHANG Shujun,CHENG Zhenxiang,CHEN Huanchu,
.

科学通报(英文版) , 2000,
Abstract: The methods to grow a novel upconversion crystal Ba2ErCl7 are reported in this note. Ba2ErCl7 material was synthesized with Er2O3, BaCl2·2H2O and NH4Cl by using a so-called “direct synthesis method”. High quality Ba2ErCl7 single crystals with size up to 4 mm×8 mm×15 mm were grown by using the Czochralski and the Bridgman methods. Intense yellow-green luminescence was detected when the crystal was pumped by an 803 laser diode (LD). Transmittance spectrum was measured by using HITACH U-3500 spectrophotometer at room temperature for the first time, in which one can see that the transmittance is high in the range from 350 to 1 600 nm and the cut-off wavelength of the crystal was 230 nm. The upconversion mechanisms were discussed.
Research on the Dynamic Hysteresis Loop Model of the Residence Times Difference (RTD)-Fluxgate
Yanzhang Wang,Shujun Wu,Zhijian Zhou,Defu Cheng,Na Pang,Yunxia Wan
Sensors , 2013, DOI: 10.3390/s130911539
Abstract: Based on the core hysteresis features, the RTD-fluxgate core, while working, is repeatedly saturated with excitation field. When the fluxgate simulates, the accurate characteristic model of the core may provide a precise simulation result. As the shape of the ideal hysteresis loop model is fixed, it cannot accurately reflect the actual dynamic changing rules of the hysteresis loop. In order to improve the fluxgate simulation accuracy, a dynamic hysteresis loop model containing the parameters which have actual physical meanings is proposed based on the changing rule of the permeability parameter when the fluxgate is working. Compared with the ideal hysteresis loop model, this model has considered the dynamic features of the hysteresis loop, which makes the simulation results closer to the actual output. In addition, other hysteresis loops of different magnetic materials can be explained utilizing the described model for an example of amorphous magnetic material in this manuscript. The model has been validated by the output response comparison between experiment results and fitting results using the model.
Null Polynomials modulo m
Shujun Li
Mathematics , 2005,
Abstract: This paper studies so-called "null polynomials modulo m", i.e., polynomials with integer coefficients that satisfy f(x)=0 (mod m) for any integer x. The study on null polynomials is helpful to reduce congruences of higher degrees modulo m and to enumerate equivalent polynomial functions modulo m, i.e., functions over Z_m={0, ..., m-1} generated by integer polynomials. The most well-known null polynomial is f(x)=x^p-x modulo a prime p. After pointing out that null polynomials modulo a composite can be studied by handling null polynomials modulo each prime power, this paper mainly focuses on null polynomials modulo p^d (d>=1). A typical monic null polynomial of the least degree modulo p^d is given for any value of d>=1, from which one can further enumerate all null polynomials modulo p^d. The most useful result obtained in this paper are Theorem 32 in Sec. 4.4 and its derivative -- Theorem 34 in Sec. 4.5. The results given in Sec. 4.3 form a basis of the induction proofs given in Sec. 4.4. However, if you do not care how the proofs in Sec. 4.4 were established, you can simply skip Sec. 4.3. Theorems 28 and 31 are very important for the proof of Theorem 32 and should be paid more attention. Note: After finishing this draft, we noticed that some results given in this paper have been covered in Kempner's papers [3,4]. Since we use a different way to obtain the results, this work can be considered as an independent and different proof. For a brief introduction to Kempner's proof, see the Appendix of this paper.
Evaluating Two Determinants
Shujun Li
Mathematics , 2005,
Abstract: This article evaluates the determinants of two classes of special matrices, which are both from a number theory problem. Applications of the evaluated determinants can be found in [arXiv:math.NT/0509523]. Note that the two determinants are actually special cases of Theorems 20 and 23 in [arXiv:math.CO/9902004], respectively. Since this paper does not provide any new results, it will not be published anywhere.
Permutation Polynomials modulo m
Shujun Li
Computer Science , 2005,
Abstract: This paper mainly studies problems about so called "permutation polynomials modulo $m$", polynomials with integer coefficients that can induce bijections over Z_m={0,...,m-1}. The necessary and sufficient conditions of permutation polynomials are given, and the number of all permutation polynomials of given degree and the number induced bijections are estimated. A method is proposed to determine all equivalent polynomials from the induced polynomial function, which can be used to determine all equivalent polynomials that induce a given bijection. A few problems have not been solved yet in this paper and left for open study. Note: After finishing the first draft, we noticed that some results obtained in this paper can be proved in other ways (see Remark 2). In this case, this work gives different and independent proofs of related results.
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