头皮机械刺激通过控制脑水肿减轻2-VO大鼠脑低灌注

目的:探讨头皮机械刺激(SMS),作用机理与头针相似,对脑低灌注大鼠脑水肿的脑保护作用。方法:首先,我们通过测量皮肤温度和脑血流量来筛选SMS的强度。接下来,我们观察了头皮机械刺激对2-VO模型大鼠脑血流量、脑水肿和相关病理学改变的脑保护作用。利用免疫组化和免疫印迹法检测神经凋亡相关蛋白(caspase-3、cleaved-caspase-3)和脑水肿相关蛋白(GFAP和AQP4)的表达差异。随后分析神经细胞凋亡与AQP4蛋白水平的相关性。结果:0.5 N为最适合本研究的刺激强度。与对照组相比,0.5 N、1 N、2 N组均可以维持头皮温度,改善脑血流量(均P<0.05)。SMS干预显著增加了2-VO大鼠脑血流量,降低脑含水量(P<0.001和P=0.0449)。与2-VO组相比,SMS组大鼠海马CA1区caspase-3阳性细胞数(P=0.0086)和cleavedcaspase-3阳性细胞数(P=0.036)显著减少,与caspase-3蛋白表达水平(P=0.019)相似。与sham组比较,2-VO组大鼠GFAP和AQP4表达增高(P=0.0369和P=0.0142),SMS组大鼠GFAP和AQP4表达明显降低(P=0.0484和P=0.0229)。AQP4与caspase-3、cleavedcaspase-3的表达呈正相关(R2=0.6071/R2=0.8500)。结论:本研究揭示了SMS改善脑低灌注的最佳强度及其可能的作用机制。SMS可能是一种简便、有前景的预防缺血性卒中和认知障碍的方法。

Structural characterization of sulfated galactofucan from Undaria pinnatifida and its effect on type 2 diabetic mice

A sulfated galactoftucan designated as UpG was obtained from the brown algae Undaria pinnatifida by calcium chloride extraction.Chemical analyses showed that UpG is composed of galactose and fucose at a high sulfation level.Low-molecular weight UpGP-0.5 was prepared from UpG through acid hydrolysis for structure characterization.The backbones of UpG are determined to beα-(1,3)-Fuc,α-(1,4)-Gal,α-(1,3)-Gal,andα-(1,6)-Gal by GC-MS,FT-IR,NMR,and LC-MS analyses.Sulfate groups are modified at C2 and/or C4 of fucose and C3 and/or C4 of galactose.UpG could partially lower blood sugar and serum lipid levels in type 2 diabetic mice.Moreover,UpG treatment regulates the abundance of some specific gut microbiota,such as enriching the abundance of Muribaculum and Christensenellaceae,and reducing that of Bilophila,Tannerellaceae,Candidatus Saccharimonas and Anaerotruncus.The findings characterized the detailed structure of a sulfated galactofucan and investigated its potential for the treatment of type 2 diabetes mellitus.

Sodium Abundances in Very Metal-poor Stars

Chemical composition of very metal-poor(VMP)stars can provide observational constraints on current models of nucleosynthesis and the chemical evolution of the Galaxy.It has been found that the scatter of[Na/Fe]versus[Fe/H]in VMP stars is very large in contrast with most other elements.Moreover,a negative slope in[Na/Fe]versus[Fe/H]was found for giants,which is very unlikely according to the theory of nucleosynthesis.For the sample of93 VMP stars in the metallicity range-4.25<[Fe/H]<-1.64 we obtained NLTE sodium abundances using the line profile fitting method by employing accurate atmospheric parameters determined when taking into account NLTE line formation for both FeⅠand FeⅡ.Originally selected from the LAMOST low-resolution spectral database,the spectra of stars were obtained with the High Dispersion Spectrograph of the Subaru Telescope.For 57turn-off stars in metallicity domain-3.04<[Fe/H]<-1.64,we obtained mean[Na/Fe]=-0.29±0.14 and positive slope 0.09±0.06.For 21 giants distributed over metallicity-3.59<[Fe/H]<-2.19,we found mean[Na/Fe]=-0.35±0.1 and positive slope 0.07±0.07.Our[Na/Fe]trend is lower by~0.2 dex,compared to the modern GCE model.We believe the GCE model should be adjusted,by considering the associated scatter.Twelve stars in our sample are found to be outliers,with too low or too high Na abundances.

长链非编码RNA--抗病毒天然免疫应答的新兴调控因子

长链非编码RNA(long non-coding RNAs,lncRNAs)是长度超过200nt的非编码RNA分子的总称。作为一类重要的基因调控因子,lncRNAs在表观遗传学、转录及转录后等多个水平调控靶基因的表达。近年来的研究表明,许多lncRNAs可被病毒或干扰素(interferon,IFN)诱导表达,并作为调控因子在IFN介导的抗病毒天然免疫应答中调节抗病毒相关基因的表达。本文重点阐述了lncRNAs在IFN介导的抗病毒天然免疫应答中的调控作用,尤其是对干扰素刺激基因(interferon-stimulated genes,ISGs)转录的调控作用,并归纳了lncRNAs、IFN和ISGs形成的调控网络,以期为从事lncRNAs调控IFN介导的抗病毒天然免疫应答机制研究的相关科研人员提供参考。

Directional solidification of metal-gas eutectic and fabrication of regular porous metals

Directional solidification of metal-gas eutectic (Gasar) is a novel process for making regular porous metals.This process is based on a solid-gas eutectic reaction involving a gaseous medium and a metal or a ceramic phase, andallows an easy control of the porosity, such as its pore size, pore orientation and morphology in a wide range by properlyadjusting its melting and solidification conditions. The latest progress and our research work in this field are reviewed inthis paper.

Development of a concentration method for detection of tobacco mosaic virus in irrigation water

Tobacco mosaic virus(TMV) causes significant yield loss in susceptible crops irrigated with contaminated water. However, detection of TMV in water is difficult owing to extremely low concentrations of the virus. Here, we developed a simple method for the detection and quantification of TMV in irrigation water. TMV was reliably detected at concentrations as low as 10 viral copies/μL with real-time PCR. The sensitivity of detection was further improved using polyethylene glycol 6000(PEG6000, MW 6000) to concentrate TMV from water samples. Among the 28 samples from Shaanxi Province examined with our method, 17 were tested positive after virus concentration. Infectivity of TMV in the original water sample as well as after concentration was confirmed using PCR. The limiting concentration of TMV in water to re-infect plants was determined as 102 viral copies/mL. The method developed in this study offers a novel approach to detect TMV in irrigation water, and may provide an effective tool to control crop infection.

Inactivated Pseudomonas PE(△Ⅲ)exotoxin fused to neutralizing epitopes of PEDV S proteins produces a specific immune response in mice

Porcine epidemic diarrhea(PED)caused by the porcine epidemic diarrhea virus(PEDV),is a severe infectious and devastating swine disease that leads to serious economic losses in the swine industry worldwide.An increased number of PED cases caused by variant PEDV have been reported in many countries since 2010.S protein is the main immunogenic protein containing some B-cell epitopes that can induce neutralizing antibodies of PEDV.In this study,the construction,expression and purification of Pseudomonas aeruginosa exotoxin A(PE)without domain Ⅲ(PE△Ⅲ)as a vector was performed for the delivery of PEDV S-A or S-B.PE(△Ⅲ)PEDV S-A and PE(△Ⅲ)PEDV S-B recombinant proteins were confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis.The immunogenicity of PEDV S-A and PEDV S-B subunit vaccines were evaluated in mice.The results showed that PEDV-S-B vaccine could not only induce specific humoral and Th1 type-dominant cellular immune responses,but also stimulate PEDV-specific mucosal immune responses in mice.PEDV-S-B subunit vaccine is a novel candidate mucosal vaccine against PEDV infection.

Pore structure of porous Mg-1Mn-xZn alloy fabricated by metal–gas eutectic unidirectional solidification

Lotus-type porous Mg-1 wt.% Mn-xZn(x = 0 wt.%, 1 wt.% and 2 wt.%) alloys were fabricated by metal–gas eutectic unidirectional solidification(the Gasar method). Effects of Zn addition and the fabrication process on the porosity, pore diameter and microstructure of the porous Mg alloys were investigated. Zn addition from 0 wt.% to 1 wt.% and 2 wt.% to the Mg-1 wt.% Mn alloy decreased the porosity from41.2% to 36.9% and 35.8%, respectively, with the same preparation processing. In the lotus-type porous Mg-1 wt.%Mn-1 wt.%Zn alloy, the porosities and average pore diameters changed with hydrogen pressures from 0.1 to 0.6 MPa. Conical areas that were rich in elemental Zn existed below the directional pores, and precipitates were also found in conical areas. Homogeneous directional pores existed in the lower portion of the ingot, and coarser directional pores and finer non-directional pores formed in the upper part. A theoretical model of the change in porosity with hydrogen pressure agreed well with the calculated porosities in the steady bubble growing area. The compressive strength of Mg-1 wt.Mn-Zn alloys can be increased by around 20 MPa through rising Zinc content from 1 wt.% to 2 wt.%, which basically linearly decline with the increasing of porosity. This work provides the basis for Gasar Mg-Zn-Mn alloy synthesis in biological applications and shows that the Gasar process is a promising method to fabricate Mg-Zn-Mn alloys with directional pores and a controllable pore structure.

Ex vivo cartilage explant model for the evaluation of chondrocyte-targeted exosomes

There is no efficient tracking system available for the therapeutic molecules delivered to cartilage.The dense matrix covering the cartilage surface is the main biological barrier that the therapeutic molecules must overcome.In this study,we aimed to establish a system that can dynamically and effectively track the therapeutic molecules delivered to cartilage.To this aim,we adopted bovine and human cartilage explants as ex vivo models for chondrocyte-targeted exosome dispersion.The efficiency of drug delivery was evaluated using frozen sections.The results of this study showed that the penetration and distribution of chondrocyte-targeted exosomes in cartilage explants can be tracked dynamically.Thus,ex vivo cartilage explants provide an effective and economic system to evaluate therapeutic drugs encapsulated in chondrocyte-targeted exosomes in preclinical studies.

Upper-Bound Limit Analysis of the Multi-Layer Slope Stability and Failure Mode Based on Generalized Horizontal Slice Method

Multi-layer slopes are widely found in clay residue receiving fields.A generalized horizontal slice method(GHSM)for assessing the stability of multi-layer slopes that considers the energy dissipation between adjacent horizontal slices is presented.In view of the upper-bound limit analysis theory,the energy equation is derived and the ultimate failure mode is generated by comparing the sliding surface passing through the slope toe(mode A)with that below(mode B).In addition,the influence of the number of slices on the stability coefficients in the GHSM is studied and the stable value is obtained.Compared to the original method(Chen’s method),the GHSM can acquire more precise results,which takes into account the energy dissipation in the inner sliding soil mass.Moreover,the GHSM,limit equilibrium method(LEM)and numerical simulation method(NSM)are applied to analyze the stability of a multi-layer slope with different slope angles and the results of the safety factor and failure mode are very close in each case.The ultimate failure modes are shown to be mode B when the slope angle is not more than 28°.It illustrates that the determination of the ultimate sliding surface requires comparison of multiple failure modes,not only mode A.

Characterization of Macro-and Meso-Scale Shear Behavior of Soil-Brick Mixtures with Different Contents and Shapes of Brick by Discrete Element Method

Due to urban construction and renovation projects,a large amount of construction and demolition waste(CDW)is increasing year by year in China.Among them,soil-brick mixture(SBM)is most widely landfilled because many older brick buildings were constructed in the last century(Zhang et al.,2022;Xu et al.,2021).Since the SBM is composed of two kinds of geotechnical materials,its mechanical properties are more complex than those of the single material.They depend not only on the mechanical properties of the individual components such as soil and brick,but also on the relative content of these components and the shape of the coarse particles(Zhu et al.,2021).The shear properties of SBM directly affect the stability of slope and paving engineering;therefore,it is significant to study the mechanical properties of SBM.

Hi-TOM: a platform for high-throughput tracking of mutations induced by CRISPR/Cas systems

The CRISPR/Cas system has been extensively applied to make precise genetic modifications in various organisms. Despite its importance and widespread use, large-scale mutation screening remains time-consuming, labour-intensive and costly. Here, we developed Hi-TOM(available at http://www.hi-tom.net/hi-tom/), an online tool to track the mutations with precise percentage for multiple samples and multiple target sites. We also described a corresponding next-generation sequencing(NGS) library construction strategy by fixing the bridge sequences and barcoding primers. Analysis of the samples from rice, hexaploid wheat and human cells reveals that the Hi-TOM tool has high reliability and sensitivity in tracking various mutations, especially complex chimeric mutations frequently induced by genome editing. Hi-TOM does not require special design of barcode primers,cumbersome parameter configuration or additional data analysis. Thus, the streamlined NGS library construction and comprehensive result output make Hi-TOM particularly suitable for high-throughput identification of all types of mutations induced by CRISPR/Cas systems.

Manipulating mRNA splicing by base editing in plants

Precursor-mRNAs(pre-mRNA) can be processed into one or more mature m RNA isoforms through constitutive or alternative splicing pathways. Constitutive splicing of pre-mRNA plays critical roles in gene expressional regulation, such as intronmediated enhancement(IME), whereas alternative splicing(AS) dramatically increases the protein diversity and gene functional regulation. However, the unavailability of mutants for individual spliced isoforms in plants has been a major limitation in studying the function of mRNA splicing. Here, we describe an efficient tool for manipulating the splicing of plant genes. Using a Cas9-directed base editor, we converted the 5′ splice sites in four Arabidopsis genes from the activated GT form to the inactive AT form. Silencing the AS of HAB 1.1(encoding a type 2 C phosphatase) validated its function in abscisic acid signaling, while perturbing the AS of RS31 A revealed its functional involvement in plant response to genotoxic treatment for the first time. Lastly,altering the constitutive splicing of Act2 via base editing facilitated the analysis of IME. This strategy provides an efficient tool for investigating the function and regulation of gene splicing in plants and other eukaryotes.

Tobacco RING E3 Ligase NtRFP1 Mediates Ubiquitination and Proteasomal Degradation of a Geminivirus-Encoded βC1

The βC1 protein encoded by the Tomato yellow leaf curl China virus-associated betasatellite functions as a pathogenicity determinant. To better understand the molecular basis whereby βC1 functions in pathogenicity, a yeast two-hybrid screen of a tobacco cDNA library was carried out using βC1 as the bait. The screen revealed that βC1 interacts with a tobacco RING-finger protein designated NtRFP1, which was further confirmed by the bimolecular fluorescence complementation and co-immunoprecipitation assays in Nicotiana benthamiana cells. Expression of NtRFP1 was induced by βC1, and in vitro ubiquiti- nation assays showed that NtRFP1 is a functional E3 ubiquiUn ligase that mediates βC1 ubiquitination. In addition, βC1 was shown to be ubiquitinated in vivo and degraded by the plant 26S proteasome. After viral infection, plants overexpressing NtRFP1 developed attenuated symptoms, whereas plants with silenced expression of NtRFP1 showed severe symptoms. Other lines of evidence showed that NtRFP1 attenuates βC1-induced symptoms through promoting its degradation by the 26S proteasome. Taken together, our results suggest that tobacco RING E3 ligase NtRFP1 attenuates disease symptoms by interacting with βC1 to mediate its ubiquitination and degradation via the ubiquitin/26S proteasome system.

Mercury oxidation and adsorption characteristics of potassium permanganate modified lignite semi-coke

The adsorption characteristics of virgin and potassium permanganate modified lignite semi-coke （SC） for gaseous Hg were investigated in an attempt to produce more effective and lower price adsorbents for the control of elemental mercury emission. Brunauer-Emmett- Teller （BET） measurements, X-ray powder diffraction （XRD） and X-ray photoelectron spectroscopy （XPS） were used to analyze the surface physical and chemical properties of SC, Mn-SC and Mn-H-SC before and after mercury adsorption. The results indicated that potassium permanganate modification had significant influence on the properties of semi-coke, such as the specific surface area, pore structure and surface chemical functional groups. The mercury adsorption efficiency of modified semi-coke was lower than that of SC at low temperature, but much higher at high temperature. Amorphous Mn7＋, Mn6＋ and Mn4＋ on the surface of Mn-SC and Mn-H-SC were the active sites for oxidation and adsorption of gaseous Hg~, which oxidized the elemental mercury into Hg2＋ and captured it. Thermal treatment reduced the average oxidation degree of Mn2＋ on the surface of Mn-SC from 3.80 to 3.46. However, due to the formation of amorphous MnOx, the surface oxidation active sites for gaseous Hg0 increased, which gave Mn-H-SC higher mercury adsorption efficiency than that of Mn-SC at high temperature.

Generation of thermosensitive male-sterile maize by targeted knockout of the ZmTMS5 gene

Maize（Zea mays L.）is one of the most important cereal crops,with a global production of 1.02 billion tons in 2013（Baldaufa et al.,2016）.Heterosis is widely used to increase the productivity of maize,and the first commercial hybrid maize was introduced in the 1930s（Duvick,2001）.

Efficient genetic transformation and CRISPR/Cas9-mediated genome editing of watermelon assisted by genes encoding developmental regulators

Cucurbitaceae is an important family of flowering plants containing multiple species of important food plants,such as melons,cucumbers,squashes,and pumpkins.However,a highly efficient genetic transformation system has not been established for most of these species(Nanasato and Tabei,2020).Watermelon(Citrullus lanatus),an economically important and globally cultivated fruit crop,is a model species for fruit quality research due to its rich diversity of fruit size,shape,flavor,aroma,texture.

Effect of copper on magnetostriction and mechanical properties of TbDyFe alloys

The intrinsic brittleness of the TbDyFe alloy significantly decreases its mach inability and applications.This paper aims to improve the toughness of TbDyFe alloy by adding Cu. Various alloys of the type(Tb_(0.3)Dy_(0.7))_(0.37)Fe_(0.63-χ)Cu_χ(χ=0, 0,01.0.03, 0.05, 0.08, 0.1) were fabricated by an arc melting furnace under a high purity argon atmosphere. The microstructure, magnetostrictive properties and mechanical performance were studied systematically. The results show that the (Tb,Dy)Cu phase forms in these alloys upon the addition of Cu. Correspondingly, their toughness improves, attributed to the formation of a (Tb,Dy)Cu phase. Compared to the Cu-free alloy, the fracture toughness (Kic) increases 2-3 times with increasing Cu content. However, the magnetostriction performance of these alloys declines with Cu addition, due to the low-magnetic performance of the (Tb,Dy)Cu phase at room temperature. Compared with other alloys, the alloy with the addition of 1at%Cu shows the best compromise between the saturation magnetostriction and fracture toughness.

Springback characteristics in U-channel forming of tailor rolled blank

Residual stress developed during the rolling process of tailor rolled blank （TRB） can affect the springback of finished parts considerably. Springback characteristics of unannealed and annealed TRBs were investigated by means of numerical simulation and experiments taking U-Channel as an example. TRBs were annealed by the annealing process （700 ℃, holding time 10 h）, then stamping and springback processes of unannealed and annealed TRBs were simulated, and corresponding experiments were also carried out. Effects of the transition zone length, the blank thickness, the friction coefficient and the die clearance on the springback of TRB were analyzed. The results demonstrate that the springback of TRB annealed at 700 ~C for 10 h re- duces significantly. For unannealed and annealed U-Channels, the springback of TRB U-Channel is in direct proportion to the die clearance and is in inverse proportion to the transition zone length, the blank thickness and the friction coefficient. Spring- backs of the thinner monolithic （uniform thickness） blank, the thinner side of TRB, the thicker side of TRB and the thicker monolithic blank are sorted in descending order.

Shortening the sgRNA-DNA interface enables SpCas9 and eSpCas9(1.1)to nick the target DNA strand

The length of the sgRNA-DNA complementary sequence is a key factor influencing the cleavage activity of Streptococcus pyogenes Cas9(SpCas9)and its variants.The detailed mechanism remains unknown.Here,based on in vitro cleavage assays and base editing analysis,we demonstrate that reducing the length of this complementary region can confer nickase activity on SpCas9 and eSpCas9(1.1).We also show that these nicks are made on the target DNA strand.These properties encouraged us to develop a dual-functional system that simultaneously carries out double-strand DNA cleavage and C-to-T base conversions at separate targets.This system provides a novel tool for achieving trait stacking in plants.