鸡PPARγ基因转录本3上游开放阅读框转录后的调控作用

过氧化物酶体增殖物激活受体γ(peroxisome proliferator-activated receptor gamma,PPARγ)是脂肪生成的关键调控因子。本实验室前期研究发现,与人和鼠等哺乳动物PPARγ基因的转录本不同,鸡PPARγ基因的多个转录本5′UTR区存在上游开放阅读框(upstream open reading frames,u ORFs)。为了揭示该u ORF转录后的调控作用,本研究构建了鸡PPARγ基因转录本3(c PPARγ3)野生型5′UTR报告基因载体psi CHECK2-c PPARγ3-5′UTR-WT和u ORF突变(u ATG突变为终止密码子TGA)的5′UTR报告基因载体psi CHECK2-c PPARγ3-5′UTR-Mut。将这两个报告基因载体分别转染永生化鸡前脂肪细胞(immortalized chicken pre-adipocytes,ICPA)和鸡胚成纤维细胞DF1,检测海肾荧光素酶报告基因h Rluc活性及其m RNA表达。荧光素酶报告基因检测结果显示,在ICPA细胞中,psi CHECK2-c PPARγ3-5′UTR-Mut的h Rluc报告基因活性极显著高于psi CHECK2-c PPARγ3-5′UTR-WT(P<0.01);在DF1细胞中,psi CHECK2-c PPARγ3-5′UTR-Mut的h Rluc报告基因活性高于psi CHECK2-c PPARγ3-5′UTR-WT,但差异不显著(P>0.05)。q RT-PCR检测h Rluc基因m RNA表达结果显示,与psi CHECK2-c PPARγ3-5′UTR-WT相比,在ICPA细胞中,psi CHECK2-c PPARγ3-5′UTR-Mut转染细胞的h Rluc基因的m RNA表达水平极显著降低(P<0.01);在DF1细胞中,psi CHECK2-c PPARγ3-5′UTR-Mut转染细胞后,h Rluc基因的m RNA表达水平也降低,但差异不显著(P>0.05)。为进一步分析该u ORF对鸡c PPARγ3的转录后调控作用,本研究又分别构建了野生型c PPARγ3真核表达载体pc DNA3.1-c PPARγ3-WT和u ORF突变的c PPARγ3真核表达载体pc DNA3.1-c PPARγ3-Mut。q RT-PCR检测c PPARγ3的m RNA表达水平,结果显示,在这两种细胞中,pc DNA3.1-c PPARγ3-Mut转染细胞的c PPARγ3 m RNA表达水平均显著低于pc DNA3.1-c PPARγ3-WT转染细胞(P<0.05),但Western blot结果显示,pc DNA3.1-c PPARγ3-Mut转染细胞的PPARγ蛋白表达水平极显著高于pc DNA3.1-c PPARγ3-WT转染细胞(P<0.01)。这些研究结果表明,5′UTR区的u ORF抑制鸡c PPARγ3的翻译。

Enhanced hydrogen evolution reaction over molybdenum carbide nanoparticles confined inside single-walled carbon nanotubes

Carbon nanotubes(CNTs) have shown as unique nanoreactors to tune the catalytic activity of confined nano-catalysts. Here we report that the catalytic performance of molybdenum carbide nanoparticles(MoC_x NPs) for the hydrogen evolution reaction(HER) process can be enhanced by encapsulation within single-walled carbon nanotubes(SWNTs) with a diameter of 1–2 nm. The catalyst with MoC_x NPs located on the interior surface of SWNTs(MoCx@SWNTs) exhibits a lower onset over-potential and a smaller Tafel slope than the one with MoC_x NPs attached on the exterior surface(MoCx/SWNTs). This is likely attributed to the much smaller particle size and the more reduced states of the confined MoC_x NPs, as well as the larger specific surface area of MoCx@SWNTs compared with Mo Cx/SWNTs. In addition, the electronic structure of the confined MoC_x NPs might be modified by the confinement effects of SWNTs, and hence the adsorption free energy of H atoms on the confined MoC_x NPs, which could also contribute to their higher performance. These results suggest that the SWNTs can be further explored for constructing novel catalysts with beneficial catalytic performance.

Empirical modeling of normal/cyclo-alkanes pyrolysis to produce light olefins

Due to the complexity of feedstock,it is challenging to build a general model for light olefins production.This work was intended to simulate the formation of ethylene,propene and 1,3-butadiene in alkanes pyrolysis by referring the effects of normal/cyclo-structures.First,the pyrolysis of n-pentane,n-hexane,n-heptane,n-octane,n-nonane,n-decane,cyclohexane,methylcyclohexane,n-hexane and cyclohexane mixtures,and n-heptane and methylcyclohexane mixtures were carried out at 650–800℃,and a particular attention was paid to the measurement of ethylene,propene and 1,3-butadiene.Then,pseudo-first order kinetics was taken to characterize the pyrolysis process,and the effects of feedstock composition were studied.It was found that chain length and cyclo-alkane content can be qualitatively and quantitively represented by carbon atom number and pseudo-cyclohexane content,which made a significant difference on light olefins formation.Furthermore,the inverse proportional/quadratic function,linear function and exponential function were proposed to simulate the effects of chain length,cycloalkane content and reaction temperature on light olefins formation,respectively.Although the obtained empirical model well reproduced feedstock conversion,ethylene yield and propene yield in normal/cycloalkanes pyrolysis,it exhibited limitations in simulating 1,3-butadiene formation.Finally,the accuracy and flexibility of the present model was validated by predicting light olefins formation in the pyrolysis of multiple hydrocarbon mixtures.The prediction data well agreed with the experiment data for feedstock conversion,ethylene yield and propene yield,and overall characterized the changing trend of 1,3-butadiene yield along with reaction temperature,indicating that the present model could basically reflect light olefins production in the pyrolysis process even for complex feedstock.

Pectin fractions extracted sequentially from Cerasus humilis:Their compositions,structures,functional properties and antioxidant activities

Three pectin fractions(water-soluble fraction(WSF),chelator-soluble fraction(CSF),and sodium carbonatesoluble fraction(NSF))were obtained from Chinese dwarf cherry(Cerasus humilis)fruits.All of them were branched low methoxylated pectins with an amorphous or partially nanocrystalline nature and eight neutral monosaccharides(arabinose and galactose were most abundant).WSF,CSF and NSF had a degree of methylation(DM)of 35.82%,14.85%and 7.13%,uronic acid(UA)content of 76.02%,83.71%and 69.01%,and total protein content of 2.4%,2.1%and 8.8%,respectively.Their molecular weights were 340.31,330.16 and 141.31 kg/mol,respectively(analyzed by gel permeation chromatography(GPC)).WSF,CSF and NSF exhibited good rheological,thermal,emulsifying,emulsion-stabilizing,water-adsorbing,oil-binding,cholesterol-binding and antioxidant properties.NSF had the highest emulsifying,emulsion stabilizing,water-/oil-/cholesterol-binding and antioxidant capacities,followed by CSF.NSF had the highest viscosity(406.77 m Pa·s),flowability,and resistance to heat-induced changes/damage,which may be related to its lowest polydispersity index,DM and UA content and highest protein content.The three pectin fractions with desirable characteristics can be used as food additives/ingredients and dietary supplements.

Experiment and modeling of coke formation and catalyst deactivation in n-heptane catalytic cracking over HZSM-5 zeolites

Since paraffins catalytic cracking was of significant importance to light olefins and aromatics production,this work was intended to gain insights into the feature and model of coke formation and catalyst deactivation in n-heptane catalytic cracking over HZSM-5 zeolites. 18 tests of n-heptane catalytic cracking were designed and carried out over HZSM-5 zeolites in a wide range of operating conditions. A particular attention was paid to the measurement of the conversion, product distribution, coke content, and the porosity and acidity of the fresh and spent HZSM-5 zeolites. It was found that alkene and aromatic promoted coke formation, and it reduced the pore volume and acid site of HZSM-5 zeolites, tailoring its performance in n-heptane catalytic cracking. The specific relationship between HZSM-5 zeolites, n-heptane conversion, product distribution and coke formation was quantitively characterized by the exponential and linear function. Based on the reaction network, the coupled scheme of coke formation and catalyst deactivation were specified for n-heptane catalytic cracking. The dual-model was proposed for the process simulation of n-heptane catalytic cracking over HZSM-5 zeolites. It predicted not only the conversion and product distribution but also coke content with the acceptable errors.

Study on Rapid Detection of Tetracyclines,Fluoroquinolones and Sulfonamides in Milk

Aiming at the market demand for rapid detection of tetracyclines,fluoroquinolones and sulfonamides in milk,a golloidal gold immunochromatography test strip for simultaneous detection of tetracyclines,fluoroquinolones and sulfonamides in milk was prepared based on the principle of competitive inhibition immunochromatography. The performance indicators of the test strip were verified. The results showed that the test strip can simultaneously detect 4 tetracyclines,13 fluoroquinolones and 13 sulfonamides,and the detection limits all can meet the national residue limits; the tests strip exhibited false positive rate≤5% and false negative rate = 0; and no cross-reaction with other drugs was commonly found in milk,indicating good specificity. The method is simple,rapid,and has low cost and easy popularization. It provides a means for realizing on-site rapid detection and is of important practical significance to guarantee of safety of milk and dairy products in China.

Modulating the CO methanation activity of Ni catalyst by nitrogen doped carbon

Nitrogen doping has been proved to be an effective way to modify the properties of graphene and other carbon materials. Herein, we explore a composite with nitrogen doped carbon overlayers wrapping Si C substrate as a support for Ni（Ni/CN-Si C） and evaluate its effects on the methanation activity. The results show that both the activity and stability of Ni are enhanced. Characterization with STEM, XRD, XPS, Raman and H2-TPR indicates that nitrogen doping generates more defects in the carbon overlayers, which benefit the dispersion of Ni. Furthermore, the reduction of Ni is facilitated.

Regional Calibration of Hargreaves Equation in the Xiliaohe Basin

This paper investigates calibration of Hargreaves equation in Xiliaohe Basin. Twelve meteorologicalgauges located within Xiliaohe Basin in Northeast China were monitored during 1970 and 2014 providing continuous records of meteorological data. Taking daily ET0 calculated by Penman-Montieth equation as the benchmark, the error of Hargreaves equation for computing ET0 was evaluated and the investigation on regional calibration of Hargreaves equation was carried out. Results showed there was an obvious difference between the calculating results of Hargreaves and Penman-Monteith equation. The estimation of the former was obviously higher during June and September while lower during the rest time in a year. The three empirical parameters of the Hargreaves equation were calibrated using the SCE-UA (Shuffled Complex Evolution) method, and the calibrated Hargreaves equation showed an obvious promotion in the accuracy both during the calibration and verification period.

Structure attack on full-round DBST

1 Introduction Block cipher is one of the most important part of symmetric cipher,which has been widely used in the field of computer communication and information system security.In order to meet the increasing demand for ensuring secure data transmission in Internet of Things(IoT)environment,lightweight block ciphers have become more and more important due to their easy software implementation,low resource consumption,ease of standardization and high security.Essentially,in order to satisfy the constraints of resource-limited devices,lightweight block ciphers strive to achieve a balance between the cost of software and hardware implementation,efficiency,and security.However,sometimes the security of lightweight block ciphers might be challenged due to the simplified structure.Thus,it is meaningful to study the type of simplified lightweight block ciphers.

Robust Alcohol Soluble Polyurethane/Chitosan/Silk Sericin(APU/CS/SS)Nanofiber Scaffolds Toward Artificial Skin Extracellular Matrices via Microfluidic Blow‑Spinning

Skin regeneration is a matter of high concern since many individuals suffer from skin damage.To date,the concept of protein-based artificial skin scaffolds have been successfully applied and proven in skin regeneration.However,realizing a skin tissue scaffold with a skin-like extracellular matrix(ECM)that combines low price,good biocompatibility,excellent antibacterial properties,good cell adhesion,and strong mechanical properties is still a major challenge.In this study,inexpensive silk sericin(SS)protein-based artificial skin nanofiber scaffolds(NFSs)with excellent biological activity,no immune rejection,and high mechanical strength were fabricated via microfluidic blow-spinning(MBS).In particular,the as-prepared NFS was transformed from a random coil structure to aβ-sheet structure by using the MBS in high-speed shear chips to improve its stability and mechanical strength.Additionally,through in vitro and in vivo studies,it was shown that SS protein-based artificial skin NFSs possessed excellent antibacterial effects and degradability properties,as well as accelerated tissue granu-lation growth,effectively promoting full skin wound healing and skin regeneration for medical problems worldwide.Thus,this skin ECM-inspired NFS offers new perspectives for accelerating wound healing and tissue regeneration and provides potential applications for clinical medicine.

A versatile method for the encapsulation of various non-precious metal nanoparticles inside single-walled carbon nanotubes

We present a facile and versatile method for introducing various non-precious metal nanoparticles （NPs） in small nanotubes, such as single-walled carbon nanotubes （SWNTs）, including 3d-metals （V, Mn, Fe and Co）, 4d-metals （Mo）, and 5d-metals （W）. This is realized by oxidizing encapsulated cycloalkene metal carbonyl complexes below their sublimation temperatures. This novel technique is significant because it avoids the diffusion and deposition of metal species on the outer walls of nanotubes, which has been challenging to achieve using the conventional filling methods. High-resolution transmission electron microscopy （HRTEM）, high angle annular dark field scanning transmission electron microscopy （HAADF-STEM）, energy-dispersive X-ray spectroscopy （EDX）, Raman, and X-ray photoelectron spectroscopy （XPS） analyses revealed high filling efficiencies （〉 95% SWNTs filled with metal NPs）. This method also provides a unique approach to fabricate highly dispersed and uniform SWNT-metal nanoparficle encapsulates with lower valence states, which are often not stable in the bulk.

Nanostructured Polymer Composite Electrolytes with Self-Assembled Polyoxometalate Networks for Proton Conduction

The key challenge for the use of polymer electrolytes is to realize a high ionic conductivity without scarifying their mechanical performance.Herein,we report a facile strategy to prepare a nanostructured polymer electrolyte with both high proton conductivity and high modulus,based on the electrostatic self-assembly of polyoxometalate cluster H_(3)PW_(12)O_(40)(PW)and comb copolymer poly(ether-etherketone)-grafted-poly(vinyl pyrrolidone)(PEEK-gPVP).The incorporation of protonic acid PW can enable the PEEK-g-PVP to be highly proton conductive and create flexible composite electrolyte membranes.Moreover,nanoscale phase separation between PEEK domains and PVP/PW domains spontaneously occurs in these membranes,forming a bicontinuous structure with three-dimensional(3D)-connected PW networks.Due to the dual role of PW networks as both proton transport pathways and mechanical enhancers,these membranes exhibit proton conductivities higher than 30 mS cm^(−1) and modulus over 4 GPa.Notably,the direct methanol fuel cells equipped with these membranes show good cell performance.Given the wide tunability of comb copolymers and polyoxometalates,this system can be extended to develop a variety of functional electrolyte materials,for example,the lithium-ion conductive electrolytes by using polyoxometalatebased lithium salts,which provides a promising platform to explore versatile electrolyte materials for energy and electronic applications.

Potential of Antibody-Dependent Cellular Cytotoxicity in Acute and Recovery Phases of SARS-CoV-2 Infection

Background:Severe acute respiratory syndrome coronavirus-2(SARS-CoV-2)has caused a global pandemic that has resulted in millions of casualties.Although researchers have reported the existence of neutralizing antibodies and viral T cell immunity against SARS-CoV-2,little is known about the presence of antibody-dependent cellular cytotoxicity(ADCC)and its role in combating SARS-CoV-2 infection.Methods:Nineteen acute COVID-19 patients at the First Affiliated Hospital of Guangzhou Medical University from January to February,2020 and 55 recovery COVID-19 patients at the Second Peoples Hospital of Changde City from February,2020 to February,2021 were recruited in this study.Longitudinal plasma samples were collected.A virus-specific ADCC assay was performed to study the COVID-19 plasma samples.The correlations between ADCC and total IgG titer,including anti-RBD,anti-N,and neutralizing antibody titer were analyzed.Results:A high level of ADCC with 0.86%of IFN-g+CD107a+NK cells induced by anti RBD antibodies and with 0.54%of IFN-g+CD107a+NK cells induced by anti N antibodies was observed.This activity peaked at 3 weeks after disease onset with 1.16%and 0.63%of IFN-g+CD107a+NK cells induced by anti RBD and anti N antibodies respectively,declined to 0.32%and 0.32%of IFN-g+CD107a+NK cells respectively after more than 2 months,and persisted for 12 months after disease onset.The ADCC did not aggravate the severity of COVID-19 in terms of sequential organ failure assessment,although ADCC decreased with the age of COVID-19 patients.Interestingly,ADCC response is not correlated with neutralizing antibody titer or total IgG titers against S protein RBD and N protein in acute patients.ADCC in recovered patients showed a significant correlation with anti RBD IgG titer(R2=0.33,P<0.001).Conclusion:Antibodies from COVID-19 patients against the N protein and S protein RBD domains could stimulate high levels of ADCC response.Our results provide evidence that vaccination should not only focus on neutralizing antibodies but also binding antibodies that may facilitate the antiviral function of ADCC,especially in the elderly.

Use of a Removable Backbone Modification Strategy to Prevent Aspartimide Formation in the Synthesis of Asp Lactam Cyclic Peptides

The synthesis of an Asp lactam derivative of A-183,a selective inhibitor of Factor 7a with good anticoagulant and antithrombotic activity,is described.Our synthesis depends on the use of a removable backbone modification(RBM)strategy to prevent aspartimide formation,which thwarted all attempts to synthesize this target using direct solid-phase peptide synthesis.Validation of the RBM strategy in the synthesis of a second Asp lactam derivative was also accomplished.The RBM strategy is therefore proposed as a general method for the synthesis of Asp lactam cyclic peptides.

Revealing the surface atomic arrangement of noble metal alkane dehydrogenation catalysts by a stepwise reduction-oxidation approach

Surface characterization of metal nanoparticles is a critical need in nanocatalysis for in-depth understanding of the structure-function relationships.The surface structure of nanoparticles is often different from the subsurface,and it is challenging to separately characterize the surface and the subsurface.In this work,theoretical calculations and extended X-ray absorption fine structure(EXAFS)analysis illustrate that the surface atoms of noble metals(Pt and Pd)are oxidized in the air,while the subsurface atoms are not easily oxidized.Taking advantage of the oxidation properties,we suggest a stepwise reduction-oxidation approach to determine the surface atomic arrangement of noble metal nanoparticles,and confirm the rationality of this approach by identifying the surface structure of typical 2-3 nm Pt and Pd nanoparticles.The reduction-oxidation approach is applied to characterize the surface structure of model Pd-Sb bimetallic catalyst,which illustrates that the surface Pd is well isolated by Sb atoms with short bond distance at 2.70Å,while there are still Pd-Pd bonds in the subsurface.Density functional theory(DFT)calculations and Pd L edge X-ray absorption near edge structure(XANES)indicate that the isolation of surface Pd significantly decreases the adsorption energies of Pd-hydrocarbon,which leads to the high propylene selectivity and turnover frequency Pd-Sb bimetallic catalyst for propane dehydrogenation.