排序方式: 共有49条查询结果,搜索用时 265 毫秒
31.
Perfluorooctane sulfonate (PFOS) and related fluorochemicals in chicken egg in China 总被引:4,自引:0,他引:4
WANG Yuan YEUNG Leo Wai Yin YAMASHITA Nobuyoshi TANIYASU Sachi SO Man Ka Margaret B. MURPHY LAM Paul Kwan Sing 《科学通报(英文版)》2008,53(4):501-507
The ubiquitous occurrence of perfluorinated compounds (PFCs) in environmental samples has drawn much attention. Recent human exposure studies found relatively high perfluorooctane sulfonate (PFOS) concentrations in blood samples from several cities in China when compared with other countries. The objectives of the present study were: (1) to measure PFC concentrations and compositions in chicken egg samples from local markets in China; and (2) to conduct a preliminary human health risk assessment of egg consumption. Eight pooled egg samples from eight locations were analyzed for 11 PFCs. The results showed that close to 100% of the PFOS in the egg was distributed in egg yolk and PFOS was not detected in egg white (〈0.08 ng/g wet weight, w/w). Of the perfluoroalkylsulfonates, only PFOS was detected in all egg samples, while of the perfluoroalkylcarboxylates, perfluoroundecanoic acid (PFUnDA) was detected in all samples, followed by perfluorooctanoate (PFOA) (75% occurrence) and perfluorodecanoic acid (PFDA) (50% occurrence). PFOS concentrations in egg ranged from 45.0 to 86.9 ng/g w/w. The results suggested that current concentrations of PFOS in domestic chicken eggs are unlikely to cause immediate harm to Chinese populations. 相似文献
32.
Hoi Man Wong Paul K. Chu Frankie K.L. Leung Kenneth M.C. Cheung Keith D.K. Luk Kelvin W.K. Yeung 《自然科学进展(英文版)》2014,24(5):561-567
In this paper, we describe the fabrication of a new biodegradable porous scaffold composed of polycaprolactone(PCL) and magnesium(Mg)micro-particles. The compressive modulus of PCL porous scaffold was increased to at least 150% by incorporating 29% Mg particles with the porosity of 74% using Micro-CT analysis. Surprisingly, the compressive modulus of this scaffold was further increased to at least 236% when the silane-coupled Mg particles were added. In terms of cell viability, the scaffold modified with Mg particles significantly convinced the attachment and growth of osteoblasts as compared with the pure PCL scaffold. In addition, the hybrid scaffold was able to attract the formation of apatite layer over its surface after 7 days of immersion in normal culture medium, whereas it was not observed on the pure PCL scaffold. This in vitro result indicated the enhanced bioactivity of the modified scaffold. Moreover, enhanced bone forming ability was also observed in the rat model after 3 months of implantation. Though bony in-growth was found in all the implanted scaffolds. High volume of new bone formation could be found in the Mg/PCL hybrid scaffolds when compared to the pure PCL scaffold. Both pure PCL and Mg/PCL hybrid scaffolds were degraded after 3 months. However, no tissue inflammation was observed. In conclusion, these promising results suggested that the incorporation of Mg micro-particles into PCL porous scaffold could significantly enhance its mechanical and biological properties. This modified porous bio-scaffold may potentially apply in the surgical management of large bone defect fixation. 相似文献
33.
The rotor spun yarn(OE yarn),twist of which is calledlayering twist,was added a few involving twist,and itsstructure and properties were measured.The experimen-tal results have shown that the morphological structure ofthe rotor spun yarn with modified twist was changed andits tensile properties and abrasion resistance were im-proved. 相似文献
34.
CL Cheung KS Lau AY Ho KK Lee SC Tiu EY Lau J Leung MW Tsang KW Chan CY Yeung YC Woo EY Cheung VH Hung HK Pang CS Hung PC Sham AW Kung 《Nature genetics》2012,44(9):1026-1029
Thyrotoxic periodic paralysis (TPP) is a potentially life-threatening complication of thyrotoxicosis. We conducted a genome-wide association study (GWAS) and a replication study with a total of 123 southern Chinese with TPP (cases) and 1,170 healthy controls and identified a susceptibility locus on chromosome 17q24.3 near KCNJ2 (rs312691: odds ratio (OR) = 3.3; P(meta-analysis) = 1.8 × 10(-14)). All subjects with TPP also had Graves' disease, and subsequent TPP versus Graves' disease comparison confirmed that the association at 17q24.3 was specific to TPP. The area under the curve (AUC) of rs312691 genotype for risk prediction of TPP in subjects with Graves' disease was 0.73. Expression quantitative trait locus (eQTL) analysis identified SNPs in the region flanking rs312691 (±10 kb) that could potentially affect KCNJ2 expression (P = 0.0001). Our study has identified a susceptibility locus associated with TPP and provides insight into the causes of TPP. 相似文献
35.
Mohammed I Yeung A Abedin A Hopkinson A Dua HS 《Cellular and molecular life sciences : CMLS》2011,68(11):1941-1952
Antimicrobial peptides are host defence molecules that play a potential role in preventing infection at the epithelial surfaces.
Ribonuclease (RNase)-7 has been shown to possess a broad spectrum of microbicidal activity against various pathogens. Here,
we demonstrate that RNase-7 protein is localised to the superficial layers of ocular surface cells and increased in response
to interleukin (IL)-1β, suggesting an active role during inflammation related to ocular surface infection. Signal transduction
pathways involved in RNase-7 expression are unknown. Involvement of transforming growth factor β-activated kinase-1 (TAK-1)
activated nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathway molecules [c-Jun N-terminal kinase
(JNK), extracellular signal-regulated kinase (ERK) and p38] were studied because of their importance in infection and inflammation.
Blocking the MAPKs resulted in inhibition of RNase-7 expression in response to IL-1β. However, RNase-7 induction by IL-1β
was not affected by inhibiting the NF-κB signalling pathway. In conclusion, our results indicate that RNase-7 expression is
specifically mediated via MAPKs but not NF-κB signalling pathways. 相似文献
36.
BA Peters BG Kermani AB Sparks O Alferov P Hong A Alexeev Y Jiang F Dahl YT Tang J Haas K Robasky AW Zaranek JH Lee MP Ball JE Peterson H Perazich G Yeung J Liu L Chen MI Kennemer K Pothuraju K Konvicka M Tsoupko-Sitnikov KP Pant JC Ebert GB Nilsen J Baccash AL Halpern GM Church R Drmanac 《Nature》2012,487(7406):190-195
Recent advances in whole-genome sequencing have brought the vision of personal genomics and genomic medicine closer to reality. However, current methods lack clinical accuracy and the ability to describe the context (haplotypes) in which genome variants co-occur in a cost-effective manner. Here we describe a low-cost DNA sequencing and haplotyping process, long fragment read (LFR) technology, which is similar to sequencing long single DNA molecules without cloning or separation of metaphase chromosomes. In this study, ten LFR libraries were made using only ~100?picograms of human DNA per sample. Up to 97% of the heterozygous single nucleotide variants were assembled into long haplotype contigs. Removal of false positive single nucleotide variants not phased by multiple LFR haplotypes resulted in a final genome error rate of 1 in 10?megabases. Cost-effective and accurate genome sequencing and haplotyping from 10-20 human cells, as demonstrated here, will enable comprehensive genetic studies and diverse clinical applications. 相似文献
37.
文章描述了一个新的鲁米诺电生化学发光流动系统。通过微铂电极流动池,H_2O_2被还原为OH~-,以维持鲁米诺化学发光所要求的pH条件。文章对鲁米诺化学发光机理进行了初步探讨,并详细研究了ECL的最佳条件。该系统明显降低了反应噪声,优于混合反应系统,可作为液相色谱间接测定检测器。 相似文献
38.
Y C Yeung K M Yu 《厦门大学学报(自然科学版)》2002,(Z1)
A typical contemporary computerized product develop me nt workflow is outlined in Fig.1. Product geometry information is first prep ared with computer-aided design (CAD) software. The CAD format can then be com municated to other downstream-computerized applications like, computer-aided e ngineering analysis (CAE), computer-aided manufacturing (CAM) and/or rapid prot otyping. Since design may need to be modified to incorporate new requirements, a loop back path is also depicted in Fig.1. The design e... 相似文献
39.
Khor CC Davila S Breunis WB Lee YC Shimizu C Wright VJ Yeung RS Tan DE Sim KS Wang JJ Wong TY Pang J Mitchell P Cimaz R Dahdah N Cheung YF Huang GY Yang W Park IS Lee JK Wu JY Levin M Burns JC Burgner D Kuijpers TW Hibberd ML;Hong Kong–Shanghai Kawasaki Disease Genetics Consortium;Korean Kawasaki Disease Genetics Consortium;Taiwan Kawasaki Disease Genetics Consortium;International Kawasaki Disease Genetics Consortium;US Kawasaki Disease Genetics Consortium;Blue Mountains Eye Study 《Nature genetics》2011,43(12):1241-1246
Kawasaki disease is a systemic vasculitis of unknown etiology, with clinical observations suggesting a substantial genetic contribution to disease susceptibility. We conducted a genome-wide association study and replication analysis in 2,173 individuals with Kawasaki disease and 9,383 controls from five independent sample collections. Two loci exceeded the formal threshold for genome-wide significance. The first locus is a functional polymorphism in the IgG receptor gene FCGR2A (encoding an H131R substitution) (rs1801274; P = 7.35 × 10(-11), odds ratio (OR) = 1.32), with the A allele (coding for histadine) conferring elevated disease risk. The second locus is at 19q13, (P = 2.51 × 10(-9), OR = 1.42 for the rs2233152 SNP near MIA and RAB4B; P = 1.68 × 10(-12), OR = 1.52 for rs28493229 in ITPKC), which confirms previous findings(1). The involvement of the FCGR2A locus may have implications for understanding immune activation in Kawasaki disease pathogenesis and the mechanism of response to intravenous immunoglobulin, the only proven therapy for this disease. 相似文献