Sequence context analysis of 8.2 million single nucleotide polymorphisms in the human genome

We analyzed n-mers (n=3-8) in the local environment of 8,249,446 human SNPs and compared their distribution with that in the genome reference sequences. The results revealed that the short sequences, which contained at least one CpG dinucleotide, occurred

The performance of closed reactor grade plutonium-thorium fuel cycles in reduced-moderation pressurised water reactors

The production of long-lived transuranic (TRU) waste is a major disadvantage of fission-based nuclear power. Previous work has indicated that TRU waste can be virtually eliminated in a pressurised water reactor (PWR) fuelled with a mixture of thorium and TRU waste, when all actinides are returned to the reactor after reprocessing. However, the optimal configuration for a fuel assembly operating this fuel cycle is likely to differ from the current configuration. In this paper, the differences in performance obtained in a reduced-moderation PWR operating this fuel cycle were investigated using WIMS. The chosen configuration allowed an increase of at least 20% in attainable burn-up for a given TRU enrichment. This will be especially important if the practical limit on TRU enrichment is low. The moderator reactivity coefficients limit the enrichment possible in the reactor, and this limit is particularly severe if a negative void coefficient is required for a fully voided core. Several strategies have been identified to mitigate this. Specifically, the control system should be designed to avoid a detrimental effect on moderator reactivity coefficients. The economic viability of this concept is likely to be dependent on the achievable thermal-hydraulic operating conditions. © 2012 Elsevier Ltd. All rights reserved.

Micromachining of glassy carbon toolsets for micro embossing applications

Laser micro machining is fast gaining popularity as a method of fabricating micro scale structures. Lasers have been utilised for micro structuring of metals, ceramics and glass composites and with advances in material science, new materials are being developed for micro/nano products used in medical, optical, and chemical industries. Due to its favourable strength to weight ratio and extreme resistance to chemical attack, glassy carbon is a new material that offers many unique properties for micro devices. The laser machining of SIGRADUR® G grade glassy carbon was characterised using a 1065 nm wavelength Ytterbium doped pulsed fiber laser. The laser system has a selection of 25 preset waveforms with optimised peak powers for different pulsing frequencies. The optics provide spot diameter of 40 μm at the focus. The effect of fluence, transverse overlap and pulsing frequency (as waveform) on glassy carbon was investigated. Depth of removal and surface roughness were measured as machining quality indicators. The damage threshold fluence was determined to be 0.29 J/cm2 using a pulsing frequency of 250 kHz and a pulse width of 18 ns (waveform 3). Ablation rates of 17 < V < 300 μm3/pulse were observed within a fluence range of 0.98 < F < 2.98 J/cm2. For the same fluence variation, 0.6 μm to 6.8 μm deep trenches were machined. Trench widths varied from 29 μm at lower fluence to 47 μm at the higher fluence. Square pockets, 1 mm wide, were machined to understand the surface machining or milling. The depth of removal using both waveform 3 and 5 showed positive correlation with fluence, with waveform 5 causing more removal than waveform 3 for the same fluence. Machined depths varied from less than 1 μm to nearly 40 μm. For transverse overlap variation using waveform 3, the best surface finish with Rz = 1.1 μm was obtained for fluence 0.792 J/cm2 for transverse overlap of 1 μm, 6 μm, and 9 μm at machined depths of 22.9 μm, 6.6 μm, and 4.6 μm respectively. For fluence of 1.426 J/cm2, the best surface finish with Rz = 1.2 μm was obtained for transverse overlap of 6 μm, and 9 μm at machined depths of 12.46 μm, and 8.6 μm respectively. The experimental data was compiled as machining charts and utilised for fabricating a micro-embossing glassy carbon master toolsets as a capability demonstration.

污水中8种雌激素化合物的定量测定

采用固相萃取-气相色谱-质谱法(GC-MS)测定污水中辛酚(OP)、壬酚(NP)、双酚A(BPA)、己烯雌酚(DES)、雌酮(E1)、17β-雌二醇(E2)、17α-乙炔雌二醇(EE2)和雌三醇(E3)8种具有雌激素活性的化合物。被测组分的加标回收率为(65.4±4.0)%～(110.0±4.5)%,检出限为1.0～7.5ng/L(相对标准偏差为5.2%～15.6%)。经检测,武汉某城市污水处理厂进水中的目标化合物(除EE2外)浓度为6.5～8954.9ng/L;除EE2和E3外,出水中的浓度为3.2～2

~(14)C标记1,2,7,8-TCDD在鲤体内分布及代谢的初步研究

利用14C标记1,2,7,8-四氯代二苯并二噁英(1,2,7,8Tetrachloro[U—14C]dibenzodioxin,14C1,2,7,8TCDD)初步研究了其在鲤体内的分布和代谢规律。14C1,2,7,8-TCDD溶解于丙酮/植物油中,腹腔暴露。暴露1、2、4、8、12d后取样,肝脏、胆汁、腹腔脂肪等消化制样后用液闪仪测量放射性活度。肝脏和胆汁内的放射性活度同步变化,都是第8d达到峰值后下降。腹腔脂肪内1—2d放射性明显高于随后取样的样品。肝和腹腔脂肪的分布量之比呈现“S”型变化趋势。暴露4d

2,3,7,8-四氯代二苯并二英(TCDD)和苯并芘(B[a]P)对原代培养鲫鱼肝细胞中卵黄蛋白原诱导的影响

通过测定原代培养鲫鱼(Carassius auratus)肝细胞中雌激素受体所介导的卵黄蛋白原(Vtg)生成以及芳香烃受体所介导的CYP1A1基因转录水平的变化, 建立了一种类雌激素体外实验模型. 实验结果表明, Vtg和Vtg mRNA的表达与己烯雌酚(DES)之间均有很好的剂量-效应关系, Vtg和Vtg mRNA均可作为指示类雌激素毒性的生物标志物. TCDD, B[a]P可显著抑制鱼肝细胞中DES诱导的Vtg和Vtg mRNA的表达, 呈明显的抗雌激素效应, 并同时激活了CYP1A1 基因的表达;

2,3,7,8-TCDD对稀有鮈鲫幼体超微结构影响的观察

国家自然科学基金29607004

Molecular characterization and expression profiles in response to bacterial infection of Chinese soft-shelled turtle interleukin-8 (IL-8), the first reptilian chemokine gene

In this study, an IL-8 homologue has been cloned and identified from a reptile, Chinese soft-shelled turtle for the first time. The full-length cDNA of turtle IL-8 was 1188 bp and contained a 312 bp open reading frame (ORF) coding for a protein of 104 amino acids. The chemokine CXC domain, which contained Glu-Leu-Arg (ELR) motif and four cysteine residues, was well conserved in turtle IL-8. The 4924 bp genomic DNA of turtle IL-8 contained four exons and three introns. Phylogenetic analysis showed that the amino acid sequence of turtle IL-8 clustered together with birds. RT-PCR analysis showed that turtle IL-8 mRNA was constitutively expressed liver, spleen, kidney, heart, blood and intestine tissues of control turtles. Real-time quantitative PCR analysis further indicated that the turtle IL-8 mRNA expression was apparent in various tissues at 8 h and up-regulated significantly during 8 h-7 d after Aeromonas hydrophila infection. The present studies will help us to understand the evolution of IL-8 molecule and the inflammatory response mechanism in reptiles. (C) 2009 Elsevier Ltd. All rights reserved.

Comparison of 100 Gb/s Ethernet links using PAM-8, multi-pulse, and hybrid CAP-16/QAM-16 modulation schemes

A theoretical study compares 100 Gb/s Ethernet links and finds that multi-pulse and hybrid CAP-16/QAM-16 (PAM-8) schemes support transmission over 10 km (2 km) SMF. Multi-pulse and CAP-16/QAM-16 need 2× the number of arithmetic operations and 7× or 3× the number of filter taps respectively but exhibit reduced power dissipation compared with PAM-8.

Elevated levels of urinary 8-hydroxy-2'-deoxyguanosine in male electrical and electronic equipment dismantling workers exposed to high concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans, polybrominated diphenyl ethers, and polychlorinated biphenyls

To investigate the occupational exposure levels to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs), indoor dust (n = 3) in workshops and hair samples from male workers (n = 64) were collected at two electrical and electronic equipment waste (E-waste) dismantling factories located in the LQ area in east China in July 11-13, 2006. Pre- and postworkshift urines (64 of each) were also collected from the workers to study oxidative damage to DNA using 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a biomarker. The concentrations of PCDD/Fs, PCDD/F-WHO-TEQs, PBDEs, PCBs and PCB-WHO-TEQs were (50.0 +/- 8.1) x 10(3), 724.1 +/- 249.6, (27.5 +/- 5.8) x 10(6), (1.6 +/- 0.4) x 10(9), (26.2 +/- 3.0) x 10(3) pg/g dry weight (dw) in dust, and (2.6 +/- 0.6) x 10(3), 42.4 +/- 9.3, (870.8 +/- 205.4) x 10(3), (1.6 +/- 0.2) x 10(6), 41.5 +/- 5.5 pg/g dw in hair, respectively. The homologue and congener profiles in the samples demonstrated that high concentrations of PCDD/Fs, PBDEs, and PCBs were originated from open burning of E-waste. The 8-OHdG levels were detected at 6.40 +/- 1.64 mu mol/mol creatinine in preworkshift urines. However, the levels significantly increased to 24.55 +/- 5.96 mu mol/mol creatinine in postworkshift urines (p < 0.05). Then, it is concluded that there is a high cancer risk originated from oxidative stress indicated by the elevated 8-OHdG levels in the E-waste dismantling workers exposed to high concentrations of PCDD/Fs, PBDEs, and PCBs.

The biological effects of rainbow trout (Oncorhynchus mykiss) recombinant interleukin-8

In this report, recombinant interieukin-8 (rIL-8) was produced and its activity tested for the first time in fish. The rainbow trout rIL-8 was produced in Escherichia coli and purified using a 6xHis tag at the N-terminus. The rIL-8 induced a dose-dependent migration of head kidney leukocytes at concentrations from 0.1 to 10 ng/ml, with a peak response at 1 ng/ml. Trout rIL-8 also had a significant effect on superoxide production by head kidney cells, with maximal, activity at 0.1 and 1 ng/ml. When injected intraperitoneally into trout, rIL-8 had a clear effect on total leukocyte number in the peritoneal cavity, with increasing doses (up to 5 mu g) eliciting more cells. Of three leukocyte types distinguished, neutrophils were the dominant cell type, especially at higher rIL-8 concentrations. In contrast, the proportion of macrophages and lymphocytes decreased with rIL-8 administration, suggesting that they were not attracted at the same rate as neutrophils. (C) 2007 Elsevier Ltd. All rights reserved.

Molecular phylogeny and biogeography of the highly specialized grade schizothoracine fishes (Teleostei : Cyprinidae) inferred from cytochrome b sequences

We recovered the phylogenetic relationships among 23 species and subspecies of the highly specialized grade schizothoracine fishes distributing at 36 geographical sites in the Tibetan Plateau and its Surrounding regions by analyzing sequences of cytochrome b genes. Furthermore, we estimated the possible divergent times among lineages based on a historical geological isolation event in the Tibetan Plateau. The molecular data revealed that the highly specialized grade schizothoracine fishes were not a monophyletic group, but were the same as genera Gymnocypris and Schizogypsis. Our results indicated that the molecular phylogenetic relationships apparently reflected their geographical and historical associations with drainages, namely species from the same and adjacent drainages clustered together and had close relationships. The divergence times of different lineages were well consistent with the rapid uplift phases of the Tibetan Plateau in the late Cenozoic, suggesting that the origin and evolution of schizothoracine fishes were strongly influenced by environment changes resulting from the upheaval of the Tibetan Plateau.

Comprehensive statistical investigation of SCM-based transmission over 300 m of FDDI-grade multimode fiber

Rigorous statistical analysis is applied for the first time to identify optimal launch conditions and carrier frequencies for SCM transmission over worst-case MMF. The feasibility of multichannel schemes for 10 Gb/s over 300 m is demonstrated. © 2005 Optical Society of America.