Perfluorooctane sulfonate （PFOS） and related fluorochemicals in chicken egg in China

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.     

Engineered polycaprolactone – magnesium hybrid biodegradable porous scaffold for bone tissue engineering

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.     

挤压速度对Ti6Al4V钛合金等通道转直角挤压过程 影响的数值模拟

采用Deform-3D有限元软件,对样品初始温度为900℃的Ti6Al4V钛合金等通道转直角挤压在0~5 mm/s的下压速度范围内进行了数值模拟。模拟计算结果表明：在相同的挤压速度下,试样通过转角后的温度降低速率减小;挤压速度越大,挤压过程所需的荷载越低,应变累积越小,等效应力越低,应力集中现象越少,挤压过程中试样的温降越小;本研究条件下,挤压速度值选定为5 mm/s。     

Partial melting of deeply subducted continental crust and the formation of quartzofeldspathic polyphase inclusions in the Sulu UHP eclogites

Two types of quartzofeldspathic inclusions hosted by omphacite and garnet were identified in the Sulu UHP eclogites. The first consists of albite, quartz, and various amounts of K-feldspar. In contrast, the second consists predominantly of K-feldspar and quartz without any albite. The presence of quartzofeldspathic inclusions within the UHP mafic eclogites indicates that partial melting occurred in deeply subducted continental crust via mica dehydration melting reactions at an early stage of rapid exhumation. Such a melting event generated hydrous Na-K-Al-Si melts. These melts infiltrated into the mafic eclogite and were captured by recrystallizing garnet or omphacite, which together followed by dehydration and crystallization to form feldspar-bearing polyphase inclusions. Formation of silicate melts within the deeply subducted continental slab not only provides an excellent medium to transport both mobile （LILE） and immobile （HFSE） elements over a large distance, but also induces effective changes in the physical properties of the UHP slab. This process could be a major factor that enhances rapid exhumation of a deeply subducted continental slab.     

Model-Based Clustering

The notion of defining a cluster as a component in a mixture model was put forth by Tiedeman in 1955; since then, the use of mixture models for clustering has grown into an important subfield of classification. Considering the volume of work within this field over the past decade, which seems equal to all of that which went before, a review of work to date is timely. First, the definition of a cluster is discussed and some historical context for model-based clustering is provided. Then, starting with Gaussian mixtures, the evolution of model-based clustering is traced, from the famous paper by Wolfe in 1965 to work that is currently available only in preprint form. This review ends with a look ahead to the next decade or so.     

从超微结构变化研究Cu2+,Zn2+,Se4+,Cd2+对三角褐指藻的毒性效应

从细胞的超微结构变化 ,主要是细胞核、囊状体和线粒体的结构变化检测了 Cu2 、Zn2 、Se4 、Cd2 对三角褐指藻的毒性作用 .其中 ,Cd2 对细胞核、囊状体的破坏严重 ,核膜破裂 ,核质均质化 .囊状体膜破碎 ,囊状体断裂甚至溶解 ,细胞内许多结构破坏而出现空洞 .其次为 Zn2 ,它对囊状体的破坏与 Cd2 相似 ,但线粒体外膜破裂 ,内嵴溶解消失而成空泡状 .Cu2 对细胞壁破坏严重 ,对囊状体和线粒体破坏与 Zn2 相似 .Se4 的毒性相对较小 ,但有些细胞核膜呈泡状外突并破裂 .     

Predation of adult razorback sucker and bonytail by striped bass in Lake Mohave, Arizona–Nevada

We report 2 separate records from sport-fish anglers in Lake Mohave, Arizona–Nevada, that document the presence of endangered razorback sucker Xyrauchen texanus and bonytail Gila elegans in stomach contents of large (13+ kg) nonnative striped bass Morone saxatilis. These records suggest that striped bass, since their first appearance in Lake Mohave nearly 3 decades ago, may have played a role in population declines of the other 2 species. Current native-fish stocking programs at Lake Mohave continue to face significant obstacles to achieving population recoveries because all life stages of repatriated individuals, including mature adults, are vulnerable to predation.     

Genome-wide association study identifies a common variant associated with risk of endometrial cancer

Endometrial cancer is the most common malignancy of the female genital tract in developed countries. To identify genetic variants associated with endometrial cancer risk, we performed a genome-wide association study involving 1,265 individuals with endometrial cancer (cases) from Australia and the UK and 5,190 controls from the Wellcome Trust Case Control Consortium. We compared genotype frequencies in cases and controls for 519,655 SNPs. Forty seven SNPs that showed evidence of association with endometrial cancer in stage 1 were genotyped in 3,957 additional cases and 6,886 controls. We identified an endometrial cancer susceptibility locus close to HNF1B at 17q12 (rs4430796, P = 7.1 × 10(-10)) that is also associated with risk of prostate cancer and is inversely associated with risk of type 2 diabetes.     

Ancestry and pharmacogenomics of relapse in acute lymphoblastic leukemia

Although five-year survival rates for childhood acute lymphoblastic leukemia (ALL) are now over 80% in most industrialized countries, not all children have benefited equally from this progress. Ethnic differences in survival after childhood ALL have been reported in many clinical studies, with poorer survival observed among African Americans or those with Hispanic ethnicity when compared with European Americans or Asians. The causes of ethnic differences remain uncertain, although both genetic and non-genetic factors are likely important. Interrogating genome-wide germline SNP genotypes in an unselected large cohort of children with ALL, we observed that the component of genomic variation that co-segregated with Native American ancestry was associated with risk of relapse (P = 0.0029) even after adjusting for known prognostic factors (P = 0.017). Ancestry-related differences in relapse risk were abrogated by the addition of a single extra phase of chemotherapy, indicating that modifications to therapy can mitigate the ancestry-related risk of relapse.     

A synonymous variant in IRGM alters a binding site for miR-196 and causes deregulation of IRGM-dependent xenophagy in Crohn's disease

Susceptibility to Crohn's disease, a complex inflammatory disease, is influenced by common variants at many loci. The common exonic synonymous SNP (c.313C>T) in IRGM, found in strong linkage disequilibrium with a deletion polymorphism, has been classified as non-causative because of the absence of an alteration in the IRGM protein sequence or splice sites. Here we show that a family of microRNAs (miRNAs), miR-196, is overexpressed in the inflammatory intestinal epithelia of individuals with Crohn's disease and downregulates the IRGM protective variant (c.313C) but not the risk-associated allele (c.313T). Subsequent loss of tight regulation of IRGM expression compromises control of intracellular replication of Crohn's disease-associated adherent invasive Escherichia coli by autophagy. These results suggest that the association of IRGM with Crohn's disease arises from a miRNA-based alteration in IRGM regulation that affects the efficacy of autophagy, thereby implicating a synonymous polymorphism as a likely causal variant.