[Show abstract][Hide abstract] ABSTRACT: Differential methylation of the homologous chromosomes, a well-known mechanism leading to genomic imprinting and X-chromosome inactivation, is widely reported at the non-imprinted regions on autosomes. To evaluate the transgenerational DNA methylation patterns in human, we analyzed the DNA methylomes of somatic and germ cells in a four-generation family. We found that allelic asymmetry of DNA methylation was pervasive at the non-imprinted loci and was likely regulated by cis-acting genetic variants. We also observed that the allelic methylation patterns for the vast majority of the cis-regulated loci were shared between the somatic and germ cells from the same individual. These results demonstrated the interaction between genetic and epigenetic variations and suggested the possibility of widespread sequence-dependent transmission of DNA methylation during spermatogenesis.
Full-text · Article · Jan 2016 · Scientific Reports
[Show abstract][Hide abstract] ABSTRACT: Measurement-based electrical characterization of through silicon via (TSV) and redistribution layer (RDL) is of great importance for both fabrication process and system design of 3D integration. This paper presents the electrical measurements and analysis of TSV and double-sided RDL test structures, from DC to high frequency up to 40 GHz. TSV shows great dependence of DC resistance and leakage current on fabrication process. An inverse V-shaped C-V curve is presented between adjacent TSVs in N-type silicon substrate, from - 10 V to 10 V. In the high frequency characterization, two methods are proposed and applied to extract resistance and inductance of a single grounded TSV. Individual transmission loss of TSV, RDLs on top and bottom surface of silicon substrate are calculated, and corresponding circuit parameters thereof are extracted to characterize their electrical properties precisely.
Full-text · Article · Jan 2016 · Microelectronic Engineering
[Show abstract][Hide abstract] ABSTRACT: The application of wavy structures in stretchable electrochemical energy storage devices is reviewed. First, the mechanical analysis of wavy structures, specific to flexible electronics, is introduced. Second, stretchable electrochemical energy storage devices with wavy structures are discussed. Finally, the present problems and challenges are reviewed, and possible directions for future research are outlined.
No preview · Article · Jan 2016 · Chinese Physics B
[Show abstract][Hide abstract] ABSTRACT: 1,2-Pentanediol and 1,5-pentanediol with high yield (~80%) could be achieved over a simple but efficient non-precious Cu–Mg3AlO4.5 bifunctional catalyst in the hydrogenolysis of biomass-derived furfuryl alcohol. The cooperative catalysis of highly dispersed metallic Cu and basic Mg3AlO4.5 drastically increases the activity and chemoselectivity.
No preview · Article · Dec 2015 · Catalysis Science & Technology
[Show abstract][Hide abstract] ABSTRACT: Study question:
Is there an association between sperm DNA methylation profiles and asthenozoospermia?
DNA methylation, at specific CpGs but not at the global level, was significantly different between low motile sperm cells of asthenozoospermic individuals and high motile sperm cells of normozoospermic controls.
What is known already:
Aberrant DNA methylation, both globally and restricted to a specific gene locus, has been associated with male infertility and abnormal semen parameters.
Study design, size, duration:
This was a case-control study investigating the differences in DNA methylation at CpGs in promoter regions between high and low motile sperm cells from eight normozoospermic controls and seven asthenozoospermic patients.
Participants/materials, setting, methods:
The liquid hybridization capture-based bisulfite sequencing method was used to determine DNA methylation at CpGs in promoter regions. The global inter-individual and intra-individual methylation variability were estimated by evaluating the methylation variance between and within different motile sperm fractions from the same or different individuals. Asthenozoospermia-associated differentially methylated or variable CpGs and differentially methylated regions were identified by comparing the DNA methylation of high motile sperm cells from normozoospermic controls with that of low motile sperm cells from asthenozoospermic patients.
Main results and the role of chance:
In this study, we determined the global DNA methylation level (24.7%), inter-individual variance (14.4%) and intra-individual differences between high and low motile sperm fractions (3.9%). We demonstrated that there were no statistically signiﬁcant differences in either the global DNA methylation level or global methylation variability between sperm from men with normozoospermia or asthenozoospermia. Between high motile sperm from men with normozoospermia and low motile sperm from men with asthenozoospermia, we identified 134 differentially methylated CpGs, 41 differentially methylated regions and 134 differentially variable CpGs. The genomic distribution patterns of the differential methylation spectrum suggested that gene expression may be affected in low motile sperm cells of asthenozoospermic patients. Finally, through a functional analysis, we detected 16 differentially methylated or variable genes that are required for spermatogenesis and sperm motility or dominantly expressed in testis.
Limitations, reasons for caution:
The sample size in this study was limited, although the participants in the two groups were carefully selected and well matched. Our results must be verified in larger cohorts with the use of different techniques. Furthermore, our results were descriptive, and follow-up studies will be needed to elucidate the effect of differential methylation profiles on asthenozoospermia.
Wider implications of the findings:
Our study identified asthenozoospermia-associated DNA methylation profiles and proposed a list of genes, which were suggested to be involved in the regulation of sperm motility through an alteration of DNA methylation. These results will provide promising clues for understanding the effect of DNA methylation on sperm motility and asthenozoospermia.
Study funding/competing interests:
This study was funded primarily by the National Natural Science Foundation of China, Shenzhen Project of Science and Technology and the National Basic Research Program of China. The authors have no competing interests.
No preview · Article · Dec 2015 · Human Reproduction
[Show abstract][Hide abstract] ABSTRACT: Few-layer black phosphorus (BP) nanosheets that are clean and of high quality, are efficiently produced by exfoliating bulk BP crystals, which are prepared by a scalable gas-phase catalytic transformation method in water. They are stable enough in water for further processing and applications. As an example, these BP nanosheets are combined with graphene to give high-performance flexible lithium ion batteries.
No preview · Article · Nov 2015 · Advanced Materials
[Show abstract][Hide abstract] ABSTRACT: The mechanism underlying pulmonary inflammation in thermal inhalation injury remains elusive. Cystic fibrosis, also hallmarked with pulmonary inflammation, is caused by mutations in CFTR, the expression of which is temperature-sensitive. We investigated whether CFTR is involved in heat-induced pulmonary inflammation. We applied heat-treatment in 16HBE14o- cells with CFTR knockdown or overexpression and heat-inhalation in rats in vivo. Heat-treatment caused significant reduction in CFTR and, reciprocally, increase in COX-2 at early stages both in vitro and in vivo. Activation of ERK/JNK, NF-κ B and COX-2/PGE 2 were detected in heat-treated cells, which were mimicked by knockdown, and reversed by overexpression of CFTR or VX-809, a reported CFTR mutation corrector. JNK/ERK inhibition reversed heat-/CFTR-knockdown-induced NF-κ B activation, whereas NF-κ B inhibitor showed no effect on JNK/ERK. IL-8 was augmented by heat-treatment or CFTR-knockdown, which was abolished by inhibition of NF-κ B, JNK/ERK or COX-2. Moreover, in vitro or in vivo treatment with curcumin, a natural phenolic compound, significantly enhanced CFTR expression and reversed the heat-induced increases in COX-2/PGE 2 /IL-8, neutrophil infiltration and tissue damage in the airway. These results have revealed a CFTR-regulated MAPK/NF-κ B pathway leading to COX-2/PGE 2 /IL-8 activation in thermal inhalation injury, and demonstrated therapeutic potential of curcumin for alleviating heat-induced pulmonary inflammation.
[Show abstract][Hide abstract] ABSTRACT: Copper is a transition metal that plays critical roles in many life processes. Controlling the cellular concentration and trafficking of copper offers a route to disrupt these processes. Here we report small molecules that inhibit the human copper trafficking proteins Atox1 and CCS, providing an approach to selectively disrupting cellular copper transport. The knockdown of Atox1 and CCS or their inhibition leads to significantly reduced proliferation of cancer cells but not normal cells, as well as attenuated tumor growth in mouse models. We show that blocking copper trafficking induces cellular oxidative stress and reduces levels of cellular ATP. The reduced level of ATP results in activation of the AMP-activated protein kinase that leads to reduced lipogenesis. Both effects contribute to inhibition of the cancer cell proliferation. Our results establish copper chaperones as new targets for future developments in anticancer therapies.
[Show abstract][Hide abstract] ABSTRACT: As human population increase, human-wildlife conflicts have reached unprecedented levels, often resulting in negative attitudes toward regional conservation initiatives, and thus are of concern for conservation communities. From April to May 2011, we carried out a survey to quantify carnivore-induced livestock losses perceived by local pastoralists in the Qinghai Lake region on the pastoral Qinghai—Tibetan Plateau and examined the ecological and socio-economic dimensions in the conflict. We finished 286 in-person interviews using a semi-structured questionnaire with mixed closed- and open-ended questions. Our results showed that 93.7% of the respondents reported livestock depredations by carnivores from March 2010 to March 2011. The perceived losses represented 3.7% of total standing value of livestock in the region. The losses were positively correlated with livestock number in each household and showed significant seasonal and diurnal difference. Adult sheep and goats were the mostly killed (54.9%), followed by lambs (21.0%), adult yaks and cattle (19.1%), calves (4.9%) and horses (0.1%). More than 80% of the respondents reported that they could not tolerate the contemporaneous depredations and nearly two thirds expected compensations for their losses. Wolf Canis lupus was blamed for most of the killings (76.0%) and was perceived most negative followed by brown bear Ursus arctos, Tibetan fox Vulpes ferrilata, red fox Vulpes vulpes and raptors. Attitudes toward the problem carnivores were positively correlated with livestock size but negatively with magnitudes of the depredations. The attitudes also varied among the three survey sites, which may be attributed to the different extent of openness and livelihood dependence on animal husbandry. In the light of our results, we suggested possible measures to mitigate the conflict and maintain coexistence between human and wild carnivores on the Qinghai—Tibetan Plateau.
[Show abstract][Hide abstract] ABSTRACT: Polyoxymethylene dimethyl ethers (DMMn), which are ideal additives for diesel fuel, are mainly synthesized from the condensation of methanol (MeOH) or dimethoxymethane (DMM) with 1,3,5-trioxane (TOX) or paraformaldehyde (PF) promoted by different acid catalysts. However, up to date, few studies have been reported to examine the formation mechanism of DMMn which is essential in understanding the reaction and valuable in designing improved catalysts. In this work, using the density functional theory (DFT) calculations combined with experiment studies, we evaluate the formation mechanism of DMMn which is promoted by sulfonic acid-functionalized ionic liquids (SO3H-FILs). Our calculated results indicate TOX and PF should dissociate into formaldehyde monomers firstly and then to react with MeOH or DMM. However, their decomposition process is different where the dissociation of TOX proceeds along a two-step mechanism while it follows a one-step mechanism for PF dissociation. As for the formation of DMMn, the reaction proceeds along a hemiacetal-carbocation pathway when MeOH is selected as the capping group provider, while the reaction follows a carbocation pathway when DMM is chosen. The origination for the product distribution pattern has also been discussed in detail. The cations and anions of ionic liquids are found synergistically promote the condensation reaction by proton transfer and simultaneously stabilizing the formed intermediated and transition states. Moreover, all the processes related to the decomposition of TOX and PF and the condensation reaction are reversible.
No preview · Article · Jul 2015 · Journal of Molecular Catalysis A Chemical
[Show abstract][Hide abstract] ABSTRACT: To reveal the toxicological effects of the hepatotoxic microcystin-leucine arginine (MC-LR) on gut microbial community composition in different gut regions, we conducted a subchronic exposure of BALB/c mice to MC-LR via intragastric administration. Denaturing gradient gel electrophoresis (DGGE) was employed to profile the shifts of microbes after MC-LR treatment in the jejuno-ileum, caecum and colon. DGGE profiles analysis showed that MC-LR increased the microbial species richness (number of microbial bands) in the caecum and colon as well as microbial diversity (Shannon-Wiener index) in the caecum. The cluster analysis of DGGE profiles indicated that the microbial structures in the caecum and colon shifted significantly after MC-LR treatment, while that in the jejuno-ileum did not. All the relatively decreased gut microbes belonged to Clostridia in the Firmicutes phylum, and most of them were Lachnospiraceae. The increased ones derived from a variety of microbes including species from Porphyromonadaceae and Prevotellaceae in the Bacteroidetes phylum, as well as Lachnospiraceae and Ruminococcaceae in the Firmicutes phylum, and among which, the increase of Barnesiella in Porphyromonadaceae was most remarkable. In conclusion, subchronic exposure to MC-LR could disturb the balance of gut microbes in mice, and its toxicological effects varied between the jejuno-ileum and the other two gut regions.
Preview · Article · Jul 2015 · The Journal of Toxicological Sciences
[Show abstract][Hide abstract] ABSTRACT: In an attempt to enhance the electrocatalytic activity and CO tolerance of ceria modified Pt/C electrodes, a novel structured ceria material has been developed. Left-handed helical CeO2 nano-spindles with mesoporous structures were successfully synthesized through a template-free based precursor method on a large scale. By a microwave-assisted polyol synthesis process, the ceria modified Pt/C electrocatalysts were synthesized. The helical CeO2 nanospindle based electrode Pt@Heli-CeO2/C exhibits superior electrochemically active surface areas, and significantly enhanced methanol oxidation catalytic activity and CO antipoisoning activity, compared to Pt/C and a nano-octahedral CeO2 modified electrode Pt@Octa-CeO2/C. The experimental results show that Pt@Heli-CeO2/C possesses 8.2 times and 3.2 times higher activity for methanol electrooxidation than Pt/C and Pt@Octa-CeO2/C, respectively. This remarkable enhancement could be attributed to the reasons as follows: compared to octahedral CeO2, the unique helical CeO2 is more conductive with better electron transfer and can provide more active surface sites to strengthen the support–metal interactions based on an electronic transfer mechanism from CeO2 to Pt, thus helical CeO2 can promote better dispersion of the Pt(0) nanocrystallites and a high concentration of metallic Pt(0) in the composition.
[Show abstract][Hide abstract] ABSTRACT: Oncogenic transcription factors are known to mediate the conversion of somatic cells to tumour or induced pluripotent stem cells (iPSCs). Here we report c-Jun as a barrier for iPSC formation. c-Jun is expressed by and required for the proliferation of mouse embryonic fibroblasts (MEFs), but not mouse embryonic stem cells (mESCs). Consistently, c-Jun is induced during mESC differentiation, drives mESCs towards the endoderm lineage and completely blocks the generation of iPSCs from MEFs. Mechanistically, c-Jun activates mesenchymal-related genes, broadly suppresses the pluripotent ones, and derails the obligatory mesenchymal to epithelial transition during reprogramming. Furthermore, inhibition of c-Jun by shRNA, dominant-negative c-Jun or Jdp2 enhances reprogramming and replaces Oct4 among the Yamanaka factors. Finally, Jdp2 anchors 5 non-Yamanaka factors (Id1, Jhdm1b, Lrh1, Sall4 and Glis1) to reprogram MEFs into iPSCs. Our studies reveal c-Jun as a guardian of somatic cell fate and its suppression opens the gate to pluripotency.
Full-text · Article · Jun 2015 · Nature Cell Biology
[Show abstract][Hide abstract] ABSTRACT: Methyl methoxyacetate (MMAc), a precursor to ethylene glycol (EG), was synthesized successfully via the liquid-phase carbonylation of dimethoxymethane (DMM) catalyzed by heteropolyacids (HPAs). The experiment results showed that H3PW12O40 (PW12) exhibited the best catalytic performance for the carbonylation of DMM, and its high catalytic activity was attributed to the synergistic effect between its superior acidic strength and the high polarity of the solvent.
No preview · Article · Jun 2015 · Chemistry Letters
[Show abstract][Hide abstract] ABSTRACT: Copper-silica nanocomposite catalysts with uniform Cu dispersion prepared by precipitation-gel method have been disclosed to be highly efficient in the heterogeneous catalysis of hydrogenation of CO2-derived cyclic carbonates, providing an indirect but practical approach for the transformation of CO2 to methanol with the co-production of diols under relatively mild conditions. The catalysts possessed remarkable stability in both batch and fixed-bed continuous flow reactors especially after promotion with B2O3. The reaction was found to depend sensitively on the Cu particle sizes, the surface acid-basicity and Cu valence of the catalysts. The synergetic effect between balanced Cu0 and Cu+ sites was considered to play a critical role for attaining high yields of methanol and diols.