3D CoNi2S4‐graphene‐2D‐MoSe2 (CoNi2S4‐G‐MoSe2) nanocomposite is designed and prepared using a facile ultrasonication and hydrothermal method for supercapacitor (SC) applications. Because of the novel nanocomposite structures and resultant maximized synergistic effect among ultrathin MoSe2 nanosheets, highly conductive graphene and CoNi2S4 nanoparticles, the electrode exhibits rapid electron and ion transport rate and large electroactive surface area, resulting in its amazing electrochemical properties. The CoNi2S4‐G‐MoSe2 electrode demonstrates a maximum specific capacitance of 1141 F g?1, with capacitance retention of ≈108% after 2000 cycles at a high charge–discharge current density of 20 A g?1. As to its symmetric device, 109 F g?1 at a scan rate of 5 mV s?1 is exhibited. This pioneering work should be helpful in enhancing the capacitive performance of SC materials by designing nanostructures with efficient synergetic effects. 相似文献
DNA methylation plays an important role for mammalian development. However, it is unclear whether the DNA methylation pattern is evolutionarily conserved. The Y chromosome serves as a powerful tool for the study of human evolution because it is transferred between males. In this study, based on deep-rooted pedigrees and the latest Y chromosome phylogenetic tree, we performed epigenetic pattern analysis of the Y chromosome from 72 donors. By comparing their respective DNA methylation level, we found that the DNA methylation pattern on the Y chromosome was stable among family members and haplogroups. Interestingly, two haplogroup-specific methylation sites were found, which were both genotype-dependent. Moreover, the African and Asian samples also had similar DNA methylation pattern with a remote divergence time. Our findings indicated that the DNA methylation pattern on the Y chromosome was conservative during human male history. 相似文献
The methylenetetrahydrofolate reductase (MTHFR) gene variant 677C→T is considered a risk factor for myocardial infarction (MI) in Caucasians, but it remains unclear whether this applies to Chinese or other Asian populations. A total of 551 controls and 304 age-matched Chinese MI patients were recruited. MTHFR genotypes were determined. A subsequent meta-analysis was performed to determine the association between MTHFR and MI in Asia. Conventional risk factors such as hypertension, diabetes mellitus and low-density lipoprotein exhibited no significant differences between the two groups. Genotype frequencies among cases and controls were compatible with Hardy–Weinberg equilibrium. The frequencies of CC, CT and TT genotypes were 28, 46 and 26 % for patients with MI and 31, 52 and 17 % for the matched control group (p = 0.006). T-allele frequency in MI patients was higher than in controls (49 vs. 43 %, odds ratio = 0.785, 95 % confidence interval = 0.644–0.958, p = 0.017). A total of 16 studies including ours were identified, involving 4053 patients and 6791 controls. A recessive genotype model of MTHFR 677C→T polymorphism, but not a dominant genotype model, was significantly associated with greater MI risk in Asians. MI risk increased 48, 37 and 47 % for the TT homozygote compared with the CC wild type, CT heterozygote and the combination of CT and CC. Thus, we conclude that the MTHFR gene variant 677C→T is a risk factor for MI in the Chinese population and the TT genotype is associated with a significant increase in MI risk in Asia. 相似文献
The evolution of gold nanoparticle (Au NP) clusters in living cells are studied by using sectional dark‐field optical microscopy and chromatic analysis approach. During endocytosis, Au NP clusters undergo fantastic color changes, from green to yellow‐orange due to the plasmonic coupling effect. Analysis of brightness/hue values of the dark‐field images helps estimate the numbers of Au NPs in the clusters. The Au NP clusters were further categorized into four groups within the endocytosis. As the results, the late endosomes had increased number of large Au NP clusters with time, while clustered numbers in secondary and tertiary groups were first increased and then decreased due to the fusion and fission of the endocytic vesicles. The time constants and cluster numbers for different groups are fitted by using an integrated rate equation, and show a positive correlation with the size of the Au NP cluster. The efficiency of Au NP uptake is only about 50% for normal cells, while 75% for cancer cells. Compared to normal cells, cancer cells show a larger number in uptake, while faster rate in removal. The propose method helps the kinetic study of endocytosed nanoparticles in physiological conditions.
Large-scale climate history of the past millennium reconstructed solely from tree-ring data is prone to underestimate the amplitude of low-frequency variability. In this paper, we aimed at solving this problem by utilizing a novel method termed “MDVM”, which was a combination of the ensemble empirical mode decomposition (EEMD) and variance matching techniques. We compiled a set of 211 tree-ring records from the extratropical Northern Hemisphere (30–90°N) in an effort to develop a new reconstruction of the annual mean temperature by the MDVM method. Among these dataset, a number of 126 records were screened out to reconstruct temperature variability longer than decadal scale for the period 850–2000 AD. The MDVM reconstruction depicted significant low-frequency variability in the past millennium with evident Medieval Warm Period (MWP) over the interval 950–1150 AD and pronounced Little Ice Age (LIA) cumulating in 1450–1850 AD. In the context of 1150-year reconstruction, the accelerating warming in 20th century was likely unprecedented, and the coldest decades appeared in the 1640s, 1600s and 1580s, whereas the warmest decades occurred in the 1990s, 1940s and 1930s. Additionally, the MDVM reconstruction covaried broadly with changes in natural radiative forcing, and especially showed distinct footprints of multiple volcanic eruptions in the last millennium. Comparisons of our results with previous reconstructions and model simulations showed the efficiency of the MDVM method on capturing low-frequency variability, particularly much colder signals of the LIA relative to the reference period. Our results demonstrated that the MDVM method has advantages in studying large-scale and low-frequency climate signals using pure tree-ring data. 相似文献
正In the past few decades,Hydrogen sulfide(H2S)has been newly witnessed as a third gasotransmitter with similar biological functions to its two previously identified counterparts nitric oxide(NO)and carbon monoxide(CO),after being rec- 相似文献
Serious bleaching events have been observed in Acropora solitaryensis, one of the main species of reef-building coral in the area of the Xisha islands in the South China Sea, during 2008–2011. The microbial communities of healthy and bleached coral samples were compared to explore the difference in the bacterial composition using 16S rRNA gene sequencing and denaturing gradient gel electrophoresis (DGGE). Analysis of 16S rRNA gene sequences showed that the diversity of bacteria from the corals was different between the healthy and the bleached. Albeit both the healthy coral and bleached coral displayed similar dominant bacterial species (α- and γ-proteobacteria), the ratio of Vibrio spp. increased sharply in the latter. As the bleaching developed, the diversity of the microbial community was dramatically decreased and the dominant species were replaced by γ-proteobacteria where Vibrio spp. and Escherichia spp. overwhelmed other genera. Similar results were gained by the DGGE technique though the abundance was lower. Furthermore, in the bleached tissues, Vibrio coralliilyticus was identified using both methods. These results indicated that pathogenic Vibrio spp. might be one of the factors causing A. solitaryensis bleaching in the coral reef of the Xisha islands. 相似文献