Cellular Senescence and SENEX Gene on the Peripheral CD4+CD25+ Treg Cells Enhancement in Elderly

Cellular senescence is a signal transduction process which maintained genomic stability and stopped mammalian cell growth. Furthermore, cellular senescence induces a protective response to a variety of DNA damage. However, this process is also associated with apoptosis, upregulated secretion of inflammatory cytokine, and promoted surrounding tissue damage. When cellular senescence accumulates to a certain extent, it triggers geriatric diseases, such as chronic inflammation, immune senescence-associated tumors and incontrollable infections. Cellular senescence gene SENEX, which was cloned in 2004, has been demonstrated to play a unique gatekeeper function in human endothelial cells when stress-induced pre-mature senescence and apoptosis occurr. The phenomenon that CD4+CD25+ Treg cells accumulated in the aged population has been well studied in recent years. Now Treg accumulation related to immune-pathology has attracted more interest. CD4+CD25+ Treg did not decline and age, but accumulated and suppressed immunoreaction. The enhanced Treg number and function may be associated with stress-induced premature senescence-mediated unique cellular senescence protection mechanisms, and SENEX may play a critical role in this process. In this article, we summarize the cellular senescence and SENEX gene in the accumulation and functional activity of CD4+CD25+ Treg in the elderly.

The Prospective Two-Dimensional Graphene Nanosheets: Preparation, Functionalization, and Applications

Graphene, as an intermediate phase between fullerene and carbon nanotube, has aroused much interests among the scientific community due to its outstanding electronic, mechanical, and thermal properties.With excellent electrical conductivity of 6000 S/cm, which is independent on chirality, graphene is a promising material for high-performance nanoelectronics, transparent conductor, as well as polymer composites. On account of its Young's Modulus of 1 TPa and ultimate strength of 130 GPa, isolated graphene sheet is considered to be among the strongest materials ever measured. Comparable with the single-walled carbon nanotube bundle,graphene has a thermal conductivity of 5000 W/(m·K), which suggests a potential application of graphene in polymer matrix for improving thermal properties of the graphene/polymer composite. Furthermore, graphene exhibits a very high surface area, up to a value of 2630 m^2/g. All of these outstanding properties suggest a wide application for this nanometer-thick, two-dimensional carbon material. This review article presents an overview of the significant advancement in graphene research: preparation, functionalization as well as the properties of graphene will be discussed. In addition, the feasibility and potential applications of graphene in areas, such as sensors, nanoelectronics and nanocomposites materials, will also be reviewed.

Discovery of a wild,genetically pure Chinese giant salamander creates new conservation opportunities

Effective conservation of threatened biota relies on accurate assessments and scientific guidance.As an unfortunate example,Chinese giant salamanders(Andrias,CGS)remain critically endangered in nature.Misguided conservation efforts,e.g.,commercial propagation and releasing of millions of likely non-indigenous or interspecific hybrids,have further compromised conservation initiatives.Limited information on wild populations of CGS poses a significant conservation challenge.Following 18-month long field monitoring,we now report the discovery of a wild population of CGS in a closed nature reserve in Jiangxi Province,China.Genomic assessments reveal its genetic distinctiveness and do not detect genetic admixture with other species.Based on morphological and molecular evidences,we describe this CGS as a new species Andrias jiangxiensis sp.nov.This is the only known species of CGS today with a genetically pure,reproducing,in situ population.This discovery emphasizes the important role that closed nature reserves play in protecting species,and the necessity of integrating long-term field monitoring and genetic assessments.It sets a new pathway for discovering and conserving endangered species,especially for those biotas that are similarly being extirpated by anthropogenic translocations and overexploitation.

A Facile Route for the Large Scale Fabrication of Graphene Oxide Papers and Their Mechanical Enhancement by Cross-linking with Glutaraldehyde

A facile route for the large scale production of graphene oxide(GO) papers and their mechanical enhancement has been presented in this work. The novel paper-like GO made from individual GO sheets in aqueous suspension can be achieved in large scale by a simple drop casting method on hydrophobic substrates.Significant enhancement in mechanical stiffness(341%) and fracture strength(234%) of GO paper have been achieved upon modification with a small amount(less than 10 wt%) of glutaraldehyde(GA). The cross-linking reaction takes place between hydroxyl groups on the surface of GO and aldehyde groups of GA, through forming hemiacetal structure, which can result in distinct mechanical enhancement of the GO papers.

Could the Recent Taal Volcano Eruption Trigger an El Ni?o and Lead to Eurasian Warming?

The Taal Volcano in Luzon is one of the most active and dangerous volcanoes of the Philippines.A recent eruption occurred on 12 January 2020(Fig.1a),and this volcano is still active with the occurrence of volcanic earthquakes.The eruption has become a deep concern worldwide,not only for its damage on local society,but also for potential hazardous consequences on the Earth’s climate and environment.

NUIST ESM v3 Data Submission to CMIP6

This paper introduces the experimental designs and outputs of the Diagnostic,Evaluation and Characterization of Klima(DECK),historical,Scenario Model Intercomparison Project(MIP),and Paleoclimate MIP(PMIP)experiments from the Nanjing University of Information Science and Technology Earth System Model version 3(NESM3).Results show that NESM3 reasonably simulates the modern climate and the major internal modes of climate variability.In the Scenario MIP experiment,changes in the projected surface air temperature(SAT)show robust“Northern Hemisphere(NH)warmer than Southern Hemisphere(SH)”and“land warmer than ocean”patterns,as well as an El Niño-like warming over the tropical Pacific.Changes in the projected precipitation exhibit“NH wetter than SH”and“eastern hemisphere gets wetter and western hemisphere gets drier”patterns over the tropics.These precipitation patterns are driven by circulation changes owing to the inhomogeneous warming patterns.Two PMIP experiments show enlarged seasonal cycles of SAT and precipitation over the NH due to the seasonal redistribution of solar radiation.Changes in the climatological mean SAT,precipitation,and ENSO amplitudes are consistent with the results from PMIP4 models.The NESM3 outputs are available on the Earth System Grid Federation nodes for data users.

Nickel-iron in the second coordination shell boost single-atomicsite iridium catalysts for high-performance urea electrooxidation

Single-atom catalysts(SACs)with high catalytic activity as well as great stability are demonstrating great promotion in electrocatalytic energy conversion,which is also a big challenge to achieve.Herein,we proposed a facile synthetic strategy to construct nickel-iron bimetallic hydroxide nanoribbon stabilized single-atom iridium catalysts(Ir-NiFe-OH),where the nickel-iron hydroxide nanoribbon not only can serve as good electronic conductor,but also can well stabilize and fully expose single-atom sites.Adopted as catalyst for urea oxidation reaction(UOR),it exhibited excellent UOR performance that it only needed a low operated potential of 1.38 V to achieve the current density of 100 mA·cm^(-2).In-situ Fourier transform infrared spectroscopy,X-ray absorption spectrum,and density functional theory calculations proved that Ir species are active centers and the existence of both Ni and Fe in the local structure of Ir atom can optimize the d-band center of Ir species,promoting the adsorption of intermediates and desorption of products for UOR.The hydrogen evolution reaction(HER)/UOR electrocatalytic cell demanded voltages of 1.46 and 1.50 V to achieve 50 and 100 mA·cm^(-2),respectively,which demonstrated a higher activity and better stability than those of conventional catalysts.This work opens a new avenue to develop catalysts for UORs with boosted activity and stability.

超强碱催化剂载体结构对丙烯二聚生成4-甲基-1-戊烯反应性能影响的研究

负载碱金属K固体超强碱为催化丙烯二聚生成4-甲基-1-戊烯(4MP1)过程的催化剂,该反应过程中催化剂载体发挥着不可忽视的作用,本工作系统地研究了4MP1生成过程中催化剂载体的作用及不同载体性能的影响规律。采用压汞仪、扫描电子显微镜(SEM)等手段对载体物质的比表面积、孔径分布等孔道结构进行表征。结果表明,当二聚反应的目标产物是4MP1时,以K_(2)CO_(3)为载体负载碱金属K所制备的催化剂具有较好的4MP1选择性,达87.38%;各载体表现出的催化性能差异主要是因为不同载体的孔道结构会产生内扩散阻力,影响丙烯二聚反应的产物分布;针对丙烯二聚反应路径及4MP1异构化反应,丙烯二聚高选择性生成4MP1应首选具有低比表面积、较大孔径、孔径分布窄的物质作为载体。

典型草原大针茅种群空间格局及对长期过度放牧的响应

种群空间格局是生态学研究的基本问题之一。典型草原带由于过度放牧退化严重,原生群落罕见,探讨原生群落的种群空间格局具有重要生态学意义。大针茅(Stipagrandis)草原是典型草原区广泛分布的主要群落类型,1979年围封的大针茅样地,是目前保存完整的大针茅草原原生群落。本文选择大针茅草原原生群落和长期过度放牧群落,应用O-Ring函数结合不同零假设模型分析了大针茅种群的空间格局。结果表明:在原生群落中大针茅种群在小尺度范围内呈均匀分布,而在长期过度放牧群落中则表现为聚集分布。这说明在大针茅草原原生群落中竞争是主要的相互作用,而在长期过度放牧群落中正相互作用居主导,验证了胁迫梯度假说;同时证明长期过度放牧改变了种群空间格局。

The gap in research on polyploidization between plants and vertebrates:model systems and strategic challenges

Polyploidization via whole-genome duplications(WGD) is a common phenomenon in organisms.However, investigations into this phenomenon differ greatly between plants and animals. Recent research on polyploid plants illustrates the immediate changes that follow WGDs and the mechanisms behind in both genetic and epigenetic consequences. Unfortunately, equivalent questions remain to be explored in animals. Enlightened by botanical research, the study of polyploidization in vertebrates involves the identification of model animals and the establishment of strategies. Here we review and comparethe research on plants and vertebrates while considering intrageneric or intraspecific variation in genome size.Suitable research methods on recently established polyploidy systems could provide important clues for understanding what happens after WGDs in vertebrates. The approach yields insights into survival and the rarity of polyploidization in vertebrates. The species of Carassius and the allopolyploid system of goldfish 9 common carp hybridization appear to be suitable models for unraveling the evolution and adaptation of polyploid vertebrates.

Effects of incident energy and angle on carbon cluster ions implantation on silicon substrate:a molecular dynamics study

Carbon cluster ion implantation is an important technique in fabricating functional devices at mi- cro/nanoscale. In this work, a numerical model is constructed for implantation and implemented with a cutting- edge molecular dynamics method. A series of simulations with varying incident energies and incident angles is performed for incidence on silicon substrate and correlated effects are compared in detail. Meanwhile, the behav- ior of the cluster during implantation is also examined under elevated temperatures. By mapping the nanoscopic morphology with variable parameters, numerical formalism is proposed to explain the different impacts on phrase transition and surface pattern formation. Particularly, implantation efficiency （IE） is computed and further used to evaluate the performance of the overall process. The calculated results could be properly adopted as the theoretical basis for designing nano-structures and adjusting devices＇ properties.