Protection of rat islet viability following heme oxygenase-1 gene transfection via adenoviral vector in vitro

Objective： To investigate the effect of Heme oxygenase-1 （HO-1） gene transfection on the viability of cultured rat islets, and to explore the potential value of HO-1 gene in islet transplantation. Methods：Recombinant adenovirus vector containing human HO-1 gene（Ad-HO-1 ） or enhanced green fluorescent protein gene（Ad-EGFP） was generated by using AdEasy system respectively. The rat islets were transfected with Ad-HO-1, Ad-EGFP or blank vector and then cultured for 7 days. Transfection was confirmed by expression of EGFP and human HO-1 protein detected by fluorescence photographs and western blot, respectively. The insulin release upon different concentration of glucose stimulation was detected using insulin radioimmunoassay kit, and stimulation index（SI） was calculated. Glucose-stimulated insulin release was used ＇to assess islet viability. Results：Adenovirus vector successfully transferred HO-1 gene to rat islet cells in vitro, and the insulin release upon high level of glucose stimulation and stimulation index （SI） of Ad-HO-1-infected islets were significantly higher than those of Ad-EGFP-infected islets and control islets （P 〈 0.05）. Conclusion： Adenovirus-mediated HO-1 gene transfection is a feasible strategy to confer cytoprotection and therefore protect the viability of cultured rat islets.

Magnetochronology of Mid-Miocene mammalian fauna in the Lanzhou Basin,northeastern Tibetan Plateau:Implications for Asian mammal migration

The Quantougou(QTG) Fauna in central Lanzhou Basin is an important late Mid-Miocene fauna on the northeastern Tibetan Plateau margin,but its numerical age remains a matter of debate.Here,we present a new magnetostratigraphic record for a fluvio-lacustrine section to further constrain the age of the QTG Fauna.Results suggest that the studied section spans from polarity chrons C5Cn.2n to C5 n.2n or C5 An.1n,with ages of ca.16.5 Ma to 10 Ma or 16.5 Ma to 12 Ma.The QTG Fauna is located at the top of polarity chron C5r.3 r or C5 Ar.2 r,which corresponds to an age of 11.7 Ma or 12.8 Ma for the fauna.Accordingly,the associated Myocricetodontinae(a subfamily of Gerbillidae,Rodentia) is suggested to have appeared in the Lanzhou Basin at 11.7 Ma or 12.8 Ma,which is the oldest Myocricetodontinae in East Asia but is still much younger than the ~20 Ma appearance of this subfamily in West and South Asia.Our age data support the interpretation that East Asian Myocricetodontinae originated from South Asia.The QTG fauna further suggest a dry and open grassland environment,which is consistent with global cooling after the Mid-Miocene Climatic Optimum.

中药槐耳可能通过Cyclin-CDKs-CKIs途径引起MOLT4细胞G_1期阻滞和诱导凋亡(英文)

Objective: The purpose of the study was to study the effect of Huaier, a traditional Chinese medicine, on the cell cycle adjustment in MOLT4 cells in vitro. Methods: We used MTT assay to test cell viability, flow cytometry to detect cell cycle and apoptosis and western blot to examine the expression of cell-cycle and apoptotic proteins in MOLT4 cells induced by Huaier. Results: Huaier could reduce the viability of MOLT4 cell by inducing G1 arrest and apoptosis. The induction of apoptosis after treatment with Huaier for 24 h was demonstrated in a dose- and time-dependent manner by flow cytometry analysis. G1 arrest induced by Huaier was modulated through the increased expression of Cdki proteins(p21cip/waf1 and p27kip1) with a simultaneous decrease in Cdk2, Cdk4, Cdk6, cyclin D1 and cyclin E expression. Huaier also induced Bax and Bcl-2 expression and activation of Caspase-3. Conclusion: It is firstly demonstrated that Huaier can inhibit proliferation of MOLT4 cells via G1 arrest and apoptosis. These results suggest that Huaier is a cell-cycle anti-cancer drug.

Existence and Uniqueness Results for a Fully Third-Order Boundary Value Problem

The boundary value problems of the third-order ordinary differential equation have many practical application backgrounds and their some special cases have been studied by many authors. However, few scholars have studied the boundary value problems of the complete third-order differential equations u′′′(t) = f (t,u(t),u′(t),u′′(t)). In this paper, we discuss the existence and uniqueness of solutions and positive solutions of the fully third-order ordinary differential equation on [0,1] with the boundary condition u(0) = u′(1) = u′′(1) = 0. Under some inequality conditions on nonlinearity f some new existence and uniqueness results of solutions and positive solutions are obtained.

Bi_(2)MoO_(6)/Bi_(7)O_(9)I_(3)异质结的制备及其光催化性能

本工作采用一步法合成了Bi_(2)MoO_(6)/Bi_(7)O_(9)I_(3)异质结材料,并采用多种手段表征异质结材料的形貌结构、化学组成和光电性能,研究了该异质结材料吸附和光催化降解环丙沙星(CIP)的效果。结果表明,与Bi_(2)MoO_(6)单体相比,Bi_(2)MoO_(6)/Bi_(7)O_(9)I_(3)复合异质结材料提高了对可见光的吸收能力,减小了其带隙宽度,从而同时提高了其作为催化材料吸附和可见光下降解CIP的活性。研究发现该复合材料中Bi_(2)MoO_(6)与Bi_(7)O_(9)I_(3)摩尔比为7:3时对CIP的去除效果最好,其中吸附去除率为82.6%,光催化降解率为94.7%。而在相同条件下,Bi_(2)MoO_(6)、Bi_(7)O_(9)I_(3)吸附去除和催化降解环丙沙星的效率分别仅为57.4%,66.4%和35.2%,43.6%。自由基捕获实验表明Bi_(2)MoO_(6)/Bi_(7)O_(9)I_(3)光催化降解环丙沙星的过程中主要活性物种为h^(+)和·O_(2)^(-)。

Optimizing and extending ion dielectric polarizability database for microwave frequencies using machine learning methods

Permittivity at microwave frequencies determines the practical applications of microwave dielectric ceramics.The accuracy and universality of the permittivity prediction by Clausius–Mossotti equation depends on the dielectric polarizability(αD)database.The most influentialαD database put forward by Shannon is facing three challenges in the 5 G era:(1)Few data,(2)Simplistic relation and(3)Low frequency(kHz–MHz)oriented.Here,we optimized and extended the Shannon’s database for microwave frequencies by the four-stage multiple linear regression and support vector machine model.In comparison with the conventional database,the optimized and extended databases achieved higher accuracy and expanded the amount of data from 60 to more than 900.Besides,we analyzed the relationships betweenαD and ion characteristics,including ionic radius(IR),atomic number(N),valence state(V)and coordination number(CN).We found that the positive cubic law of“αD~IR3”discussed in Shannon’s work was valid for the IR changed by the N,but invalid for the change caused by the CN.

Research and application of the virtual simulation system teaching method in NC machining course

Virtual simulation technology has become one of the most popular technologies in the field of engineering education after the multimedia information technology in recent years.This paper,based on the comprehensive integrated simulation and verification module of UG NX software,describes and discusses a novel virtual simulation system teaching(VSST)for numerically controlled machining to support the student engineering training to achieve the theoretical knowledge and practical techniques in numerically controlled machining.The findings of a study designed to evaluate the impact of VSST for the development of numerically controlled machining course are presented here.In addition,analysis of the follow-up surveys indicates that the VSST method enables to provide the concrete experience of interaction between the students and the simulation environment and to further stimulate students’interest in learning,so that the students who used VSST achieve significantly higher results than their co-workers.

Unusual local electric field concentration in multilayer ceramic capacitors

Local electric-field around multitype pores(dielectric pore,interface pore,electrode pore)in multilayer ceramic capacitors(MLCCs)was investigated using Kelvin probe force microscopy combined with the finite element simulation to understand the effect of pores on the electric reliability of MLCCs.Electricfield is found to be concentrated significantly in the vicinity of these pores and the strength of the local electric-field is 1.5e5.0 times of the nominal strength.Unexpectedly,the concentration degree of the pores in the inner electrode is much higher than that in the dielectrics and dielectric-electrode interfaces.Meanwhile,geometry orientations are found to have a remarkable influence on the local electric field strength.The pores act as an insulation degradation precursor via local electric,thermal center,and oxygen vacancies accumulation center.Such unusual local electric field concentration of multitype pores can provide new insights into the understanding of insulation degradation evolution,processing tailoring and design optimization for MLCCs.

二维金属氧化物和硫化物的结构调控及其高性能光电催化应用

二维金属氧化物和硫族化物具有优异的物理化学性质,在光催化和电催化应用方面具有很大的潜力,可用于析氢反应、二氧化碳还原和氮还原等许多重要的化学反应.然而,由于导电率低、活性位点少和激发电荷的快速复合,未经改性的二维金属氧化物和硫族化合物通常显示出相对较差的催化性能.因此,需要对二维金属氧化物和硫族化合物合理的结构设计和化学修饰,从而改善和提高其催化性能.基于此,本综述从插层、掺杂、构造缺陷和界面设计以及与其他功能材料的复合等方面综述了近年来二维过渡金属氧化物和硫族化合物的研究进展.同时,系统地讨论了二维金属氧化物和硫族化合物的形貌、物理化学、电子和光学性质与电催化及光催化性能之间的关系.最后,我们对该领域的前景和挑战以及未来可能的研究方向进行了展望,旨在激发更多的研究来实现基于二维过渡金属氧化物和硫族化合物催化剂在能量存储和转换领域的应用.

Two types of hyperthermal events in the Mesozoic-Cenozoic:Environmental impacts, biotic effects, and driving mechanisms

A deeper understanding of hyperthermal events in the Earth’s history can provide an important scientific basis for understanding and coping with global warming in the Anthropocene. Two types of hyperthermal events are classified based on the characteristics of the carbon isotope excursion(CIE) of the five representative hyperthermal events in the Mesozoic and Cenozoic. The first type is overall characterized by negative CIEs(NCHE) and represented by the Permian-Triassic boundary event(PTB, ~252 Ma), the early Toarcian oceanic anoxic event(TOAE, ~183 Ma), and the Paleocene-Eocene Thermal Maximum event(PETM, ~56 Ma). The second type is overall characterized by positive CIEs(PCHE) and represented by the early Aptian oceanic anoxic event(OAE1 a, ~120 Ma) and the latest Cenomanian oceanic anoxic event(OAE2, ~94 Ma).Hyperthermal events of negative CIEs(NCHE), lead to dramatic changes in temperature, sedimentation, and biodiversity. These events caused frequent occurrence of terrestrial wildfires, extreme droughts, acid rain, destruction of ozone layer, metal poisoning(such as mercury), changes in terrestrial water system, and carbonate platform demise, ocean acidification, ocean anoxia in marine settings, and various degree extinction of terrestrial and marine life, especially in shallow marine. In contrast,hyperthermal events of positive CIEs(PCHE), result in rapid warming of seawater and widespread oceanic anoxia, large-scale burial of organic matter and associated black shale deposition, which exerted more significant impacts on deep-water marine life,but little impacts on shallow sea and terrestrial life. While PCHEs were triggered by volcanism associated with LIPs in deep-sea environment, the released heat and nutrient were buffered by seawater due to their eruption in the deep sea, thus exerted more significant impacts on deep-marine biota than on shallow marine and terrestrial biota. This work enriches the study of hyperthermal events in geological history, not only for the understanding of hyperthermal events themselves, large igneous provinces, marine and terrestrial environment changes, mass extinctions, but also for providing a new method to identify the types of hyperthermal events and the inference of their driving mechanism based on the characteristics of carbon isotopic excursions and geological records.

Machine learning approaches for permittivity prediction and rational design of microwave dielectric ceramics

Low permittivity microwave dielectric ceramics(MWDCs)are attracting great interest because of their promising applications in the new era of 5G and IoT.Although theoretical rules and computational methods are of practical use for permittivity prediction,unsatisfactory predictability and universality impede rational design of new high-performance materials.In this work,based on a dataset of 254 single-phase microwave dielectric ceramics(MWDCs),machine learning(ML)methods established a high accuracy model for permittivity prediction and gave insights of quantitative chemistry/structureproperty relationships.We employed five commonly-used algorithms,and introduced 32 intrinsic chemical,structural and thermodynamic features which have correlations with permittivity for modeling.Machine learning results help identify the permittivity decisive factors,including polarizability per unit volume,average bond length,and average cell volume per atom.The feature-property relationships were discussed.The optimal model constructed by support vector regression with radial basis function kernel was validated its superior predictability and generalization by verification dataset.Low permittivity material systems were screened from a dataset of~3300 materials without reported microwave permittivity by high-throughput prediction using optimal model.Several predicted low permittivity ceramics were synthesized,and the experimental results agree well with ML prediction,which confirmed the reliability of the prediction model.

Mapping Microscale Strain Fields Around a Crack Tip in Molybdenum Via Geometric Phase Analysis and Digital Image Correlation

Uniaxial tension tests were conducted on single-edge-notched tensile specimens of pure molybdenum with a mesh grid pattern in front of the notch. A series of images of crack initialization and propagation with a distorted mesh grid pattern were obtained by means of in situ scanning electron microscopy. Strain fields around the crack tip were mapped successively using geometric phase analysis and digital image correlation techniques, and then compared with the predictions obtained through linear elastic fracture mechanics （LEFM）. The comparison shows that the measured strain distribution ahead of the crack tip is consistent with the LEFM predictions of up to 25 μm from the crack tip.

Enhanced energy storage properties of barium titanate ceramics made from surface modified particles

Surface modification of barium titanate particles has been carried out using a wet chemical method.The microstructural and dielectric properties of the ceramics made from surface modified particles were extensively investigated by X-ray diffraction,scanning electron microscopy,transmission electron microscopy,and dielectric properties measurements.The breakdown strength increased by 69%and 117%for the Al_(2)O_(3) and B_(2)O_(3)–SiO_(2) modified ceramics,respectively.An energy storage density of up to 3.2 J/cm^(3) has been obtained.The suppression of grain boundary electron transport and reduction in pore defects lead to the energy storage properties enhancement of the modified ceramics.These results indicated that surface modification of ceramic particles is a promising approach to obtain dielectric ceramics with high energy storage density.

独石结构压电陶瓷扭转驱动器

通过设计由异质单元组成的人工结构并调节其界面耦合方式,经常能够得到具有全新性质的功能器件.对压电器件来说,其变形响应来自压电晶体的伸长、压缩、剪切模态及其组合,同时取决于结构设计的边界条件.然而,由于受到晶体微观层面镜面对称性对扭转模态的限制,长期以来,在单一的集成压电元器件中实现基本扭转驱动是一个很困难的任务.本工作中,我们设计了一种共烧独石驱动器,能够初次解决这个问题.该原型器件由两组工作在反向人工剪切模态的多层驱动单元组成,它们手性的协同应力耦合将在宽频范围内产生合成的扭转输出.有限元模拟表明通过改变其几何尺寸,扭转位移可以在很大范围调节.横向挠度测试证实了其在电场作用下稳定且相当大的线性输出响应(1 Hz和40 V电压条件下约3.7μm).更重要的是,该设计方法实际上提出了在单一压电陶瓷元件中获得任意模态和驱动状态的一种更广泛的途径.

LOCAL MICROSTRUCTURE EVOLUTION OF BISMUTH SODIUM TITANATE-BASED LEAD-FREE PIEZOELECTRIC SYSTEMS ACROSS THE MORPHOTROPIC PHASE BOUNDARY REGION

Morphotropic phase boundary(MPB)containing piezoelectric systems generally exhibit enhanced piezoelectric performance at compositions within,or close to,the MPB region.The mechanism/s underlying such enhancement,however,are still contentious due to complex micro/nanostructure and apparently inherent local structural variability associated with octahedral tilt disorder/platelet precipitates in such piezoelectric materials.This paper reviews some recent structural analysis results from Bi_(0.5)Na_(0.5)TiO_(3)(BNT)and other binary,lead-free,piezoelectric materials systems derived from it via electron diffraction and in situ neutron diffraction.The results suggest that intrinsically existing local microstructure(LMS)in BNT essentially continues across the MPB region.The LMS,originating from inherent octahedral tilt disorder,is strongly temperature-,electric field-,pressure-and chemical composition-dependent,and may help to explain a series of phenomena observed in BNT-based binary materials systems,including the enhanced piezoelectric effect in the region of the MPB.

A WNT7B-m^(6)A-TCF7L2 positive feedback loop promotes gastric cancer progression and metastasis

Dear Editor,Signal transduction takes the responsibility of translating extracellular information into specific cellular activities,enabling cells,including cancer cells,to respond exquisitely to extracellular guidance cues.N6-methyladenosine(m^(6)A),the most pervasive and abundant modification within eukaryotic mRNAs,is known to have specific effects on cellular activities relevant to cancer.1 Despite the fact that m^(6)A methylation is a dynamic event involving a series of enzymes,it remains unknown whether signal transduction,much less extracellular signaling molecules,uses m^(6)A methylation as an effector mechanism in cancer.