Deactivation mechanism of acetone to isobutene conversion over Y/Beta catalyst

The conversion of acetone derived from biomass to isobutene has attracted extensive attentions.In comparison with Brønsted acidic catalyst,Lewis acidic catalyst could exhibit a better catalytic performance with a higher isobutene selectivity.However,the catalyst stability remains a key problem for the long-running acetone conversion and the reasons for catalyst deactivation are poorly understood up to now.Herein,the deactivation mechanism of Lewis acidic Y/Beta catalyst during the acetone to isobutene conversion was investigated by various characterization techniques,including acetone-temperature-programmed surface reaction,gas chromatography-mass spectrometry,in situ ultraviolet-visible,and ^(13)C cross polarization magic angle spinning nuclear magnetic resonance spectroscopy.A successive aldol condensation and cyclization were observed as the main side-reactions during the acetone conversion at Lewis acidic Y sites.In comparison with the low reaction temperature,a rapid formation and accumulation of the larger cyclic unsaturated aldehydes/ketones and aromatics could be observed,and which could strongly adsorb on the Lewis acidic sites,and thus cause the catalyst deactivation eventually.After a simple calcination,the coke deposits could be easily removed and the catalytic activity could be well restored.

基于微信的“微生物遗传育种实验”混合式教学模式探究

随着互联网的飞速发展,传统课堂教学与互联网相结合的混合式教学模式越来越受到人们的关注。微信作为使用最广泛的即时通讯软件,其公众号功能非常适合作为移动学习的平台。本文介绍了将微信应用到"微生物遗传育种实验"的教学实践,探索线上和线下结合的混合式教学模式。以"绿色荧光蛋白(green fluorescent protein,GFP)的基因定点突变实验"为例,从教学设计、建立公众号及推送素材、课前预习、课堂学习、课后复习及反馈等5个方面详细介绍混合式教学过程。GFP基因定点突变实验在引物上引入一个GFP突变位点(Y66H),以质粒p GFPuv为模板,经PCR扩增后,以DpnⅠ消化原始质粒,并转化大肠杆菌筛选蓝色荧光蛋白突变株。采用微信与课堂教学结合的模式,既方便学生与老师交流互动,又有利于学生利用碎片化时间学习,使得"教与学"更加顺畅。实践证明,这种混合式教学模式深受学生喜爱,增强了学生学习兴趣与学习自主性,显著提高了教学效果。

C/EBPα regulates SIRT1 expression during adipogenesis

SIRT1 plays an important role in adipogenesis, but how SIRT1 is regulated in adipogenesis is largely unknown. In this study, we show that both SIRT1 protein and mRNA levels were increased along with CCAAT/enhancer-binding protein a （C/EBPa） during adipocyte differentiation. C/EBPa, but not C/EBPap30, activated SIRT1 promoter in both HeLa cells and 3T3-L1 preadipocytes. Furthermore, C/EBPa upregulated SIRT1 mRNA and protein levels in HeLa cells and increased SIRT1 expression in a p53-independent manner in Soas2 cells. In preadipocytes, ectopic expression of C/EBPa upregulated SIRT1 protein level and knockdown of C/EBPa led to the decrease of SIRTI pro- tein level. Moreover, by promoter deletion analysis, gel shift assay and chromatin immunoprecipitation, we found that C/EBPa bound to the SIRT1 promoter at a consensus C/EBPα binding site. These data demonstrate that C/ EBPα regulates SIRT1 expression during adipogenesis by directly binding to the SIRT1 promoter.

Zn-Zr-Al oxides derived from hydrotalcite precursors for ethanol conversion to diethyl carbonate

Ethanol conversion to high-value-added products has attracted considerable attention in both academic research and industrial fields.In this study,we synthesized a series of tunable acid–base bifunctional Zn-Zr-Al metal oxides(represented as Zn2ZrxAl-MMO)in light of the structural topotactic transformation of Zn2ZrxAl-hydrotalcite precursors(Zn2ZrxAl-LDH).The resulting Zn2ZrxAl-MMO catalysts were employed in the conversion of ethanol to diethyl carbonate.The Zr^4+ ion content of the LDH precursor plays a key role in modulating the acid-base properties and determining catalytic performance:the Zn2Zr0.1Al-MMO sample exhibits the optimal catalytic behavior with a diethyl carbonate(DEC)yield of 42.1%,which is the highest reported for metal oxide catalysts.Structure-property correlation investigations revealed that the synergic catalysis between medium-strong basic sites and weak acid sites plays a predominant role in the catalytic behavior.Furthermore,in situ Fourier transform infrared measurements showed that the weak acidic site promotes activation adsorption of the reactant(urea)and the intermediate product(ethyl carbamate),while the medium-strong basic site accelerates ethanol activation.Moreover,the Zn2Zr0.1Al-MMO catalyst has the advantages of cost effectiveness,good stability,and reusability.Therefore,the acid-base bifunctional catalysts developed in this work can be employed as promising candidates in acid-base catalytic reactions such as ethanol conversion.

Self-aldol condensation of aldehydes over Lewis acidic rare-earth cations stabilized by zeolites

The self-aldol condensation of aldehydes was investigated with rare-earth cations stabilized by[Si]Beta zeolites in parallel with bulk rare-earth metal oxides.Good catalytic performance was achieved with all Lewis acidic rare-earth cations stabilized by zeolites and yttrium appeared to be the best metal choice.According to the results of several complementary techniques,i.e.,temperature-programmed surface reactions,in situ diffuse reflectance infrared Fourier transform spectroscopy,ultraviolet-visible diffuse reflectance spectroscopy,the reaction pathway and mechanism of the aldehyde self-aldol condensation over Y/Beta catalyst were studied in more detail.Density functional theory calculations revealed that aldol dehydration was the rate-limiting step.The hydroxyl group at the open yttrium site played an important role in stabilizing the transition state of the aldol dimer reducing the energy barrier for its hydration.Lewis acidic Y(OSi)(OH)2 stabilized by zeolites in open configurations were identified as the preferred active sites for the self-aldol condensation of aldehydes.

Xiaoyaosan-containing serum inhibits corticosterone-induced apoptosis in PC12 cells by downregulating [Ca^(2+)]_i overload

in hippocampal neurons is an important contributor to depression. [Ca^2＋]i of hippocampal neurons may raise rapidly with increased corticosterone concentrations, leading to apoptosis. The anti-depressant effects of Xiaoyaosan （Free and Easy Wanderer＇s Powder） may inhibit apoptosis by down regulating the [Ca^2＋]i overload. PC12 cells were containing with corticosterone to simulate neuronal injury, dosed with Xiaoyaosan-containing serum, and the following parameters were measured： apoptosis,[Ca^2＋]i overload, and changes in mitochondrial membrane potential （△ψm） and bioenergetics. High-dose Xiaoyaosan-containing serum （the dose of intragastric administration was 2.633 g herb/mL） not only inhibited morphological injury and cell apoptosis, but also suppressed [Ca^2＋]i overload induced by corticosterone. Xiaoyaosan also blocked the decrease in mitochondrial membrane potential and adenosine triphosphate levels induced by corticosterone. Xiaoyaosan dose-dependently suppresses corticosterone-induced apoptosis, potentially via inhibiting [Ca^2＋]ioverload, and prevents impaired mitochondrial bioenergetics by maintaining mitochondrial membrane potential and adenosine triphosphate production, providing a putative mechanism for its antidepressant effects.

Measuring solar irradiance profiles in the Arctic sea ice using fiber optic spectrometry via inclined holes

An irradiance profile measurement approach and profiling system were developed to measure the solar irradiance profile of the Arctic sea ice using fiber optic spectrometry.The approach involved using a miniature spectrometer to sense light signals collected and transmitted from a fiber probe.The fiber probe was small,and could thus move freely in inclined bore holes drilled in sea ice with its optical entrance pointing upward.The input-output relationship of the system was analyzed and built.Influence factors that determined the system output were analyzed.A correctional system output approach was proposed to correct the influence of these factors,and to obtain the solar irradiance profile based on the measurements outputted by this system.The overall performance of the system was examined in two ice floes in the Arctic during the 9th Chinese National Arctic Research Expedition.The measured solar irradiance profiles were in good agreement with those obtained using other commercially available oceanographic radiometers.The derived apparent optical properties of sea ice were comparable to those of similar sea ice measured by other optical instruments.

Magnetic excitations of diagonally coupled checkerboards

By using quantum Monte Carlo based stochastic analytic continuation(QMC-SAC)and spin wave theory,we study magnetic excitations of Heisenberg models with diagonally coupled checkerboard structures.We consider three kinds of checkerboard models(DC 2×2,DC 3×3,and CDC 3×3)consisting nearest-neighbor strong J1 and weak J2 antiferromagnetic interactions.When the coupling ratio g=J2/J1 approaches 1,all three diagonal checkerboards have the same long-range antiferromagnetic Neel order at´T=0.When g decreases,the quantum fluctuation can drive DC 2×2 model to quantum paramagnetic state,while DC 3×3 and CDC 3×3 models still have the long-range Neel order.By calculating´the magnetic excitations at different coupling ratios,we find that the low-energy part of magnetic excitations calculated by QMC-SAC can be well explained by the spin wave theory.However,the high-energy parts even deep in the long-range antiferromagnetic phase are beyond the spin wave description.Compared to the g=1 uniform square lattice,the high-energy excitations are more rich in our models.Our study may also draw the attention to the high-energy exctitaions beyond the spin wave theory.

Labor Flow Characteristics of Taian City in the Context of Rural Revitalization

[Objectives] To analyze and study the characteristics of rural labor flow to the tourism industry in Taian City of Shandong Province,and propose some measures for solving the problems of labor support in the development of rural tourism in Taian City. [Methods]The indicators were analyzed using the time series based on the relevant data on the labor employment and flow of rural households in Taian City in2005-2013. [Results] In Taian City,the number of rural laborers engaged in the primary industry decreased at the rate of 96 people/year,while the number of laborers engaged in the secondary and tertiary industries increased at the rate of 29 people/year and 3 people/year,respectively. The proportion of the three traditional tourism elements of transportation,lodging and catering in the tourism industry has been fluctuating,and the minimum was not lower than 30%. The recreational category was decreasing year by year,and only accounted for 1.7% in 2010.In summary,in the development of rural tourism in Taian City,the labor flow has problems such as low rural social security,weak attraction to young people,and large psychological barriers to returning to the hometown for employment. [Conclusions] In view of the problems,it is recommended to implement the rural revitalization strategy,attach importance to regional labor competition,give full play to the advantages of tourist cities,highlight product characteristics,increase cultural added value and improve the quality of operators to develop rural tourism. This study is intended to provide a scientific reference for talent support for rural revitalization in Taian City.

Catalytic upgrading biomass-derived ethanol and acetic acid into C4 chemicals

Synthesis of value-added chemicals from biomass is an essential strategy to mitigate the global dependency on fossil resources and achieve the aim of carbon neutrality. Thereinto, ethanol and acetic acid are crucial biomass-derived platform molecules.Recently, catalytic upgrading ethanol and acetic acid into C4 energy-intensive fuels and chemicals via the elongation of carbon backbone has received widespread attention. The primary focus of this review is to systematically describe the recent breakthrough in the conversion of ethanol or acetic acid to C4 chemicals including 1,3-butadiene, n-butenes, isobutene or n-butanol.Special attentions will be given to heterogeneous catalyst design strategies, reaction parameters on the catalytic performance along with the relevant mechanism investigations, as well as their future challenges and opportunities. The present review will provide the detailed insights into the synthesis of C4 chemicals from biomass-derived ethanol and acetic acid and shed a light on the development of highly efficient catalysts.

Hydrothermally stable metal oxide-zeolite composite catalysts for low-temperature NO_(x) reduction with improved N_(2) selectivity

Development of hydrothermally stable,low-temperature catalysts for controlling nitrogen oxides emissions from mobile sources remains an urgent challenge.We have prepared a metal oxide-zeolite composite catalyst by depositing Mn active species on a mixture support of CeO_(2)/Al_(2)O_(3) and ZSM-5.This composite catalyst is hydrothermally stable and shows improved low-temperature SCR activity and significantly reduced N_(2)O formation than the corresponding metal oxide catalyst.Comparing with a Cu-CHA catalyst,the composite catalyst has a faster response to NH_(3) injection and less NH_(3) slip.Our characterization results reveal that such an oxide-zeolite composite catalyst contains more acidic sites and Mn^(3+)species as a result of oxide-zeolite interaction,and this interaction leads to the generation of more NH_(4)^(+)species bound to the Br?nsted acid sites and more reactive NOxspecies absorbed on the Mn sites.Herein,we report our mechanistic understanding of the oxide-zeolite composite catalyst and its molecular pathway for improving the low-temperature activity and N_(2) selectivity for NH_(3)-SCR reaction.Practically,this work may provide an alternative methodology for low-temperature NO_(x) control from diesel vehicles.

The COVID-19 Vaccines Evaluation Program:Implementation,Management,and Experiences,2021-2023

In 2021,China’s domestically produced coronavirus disease 2019(COVID-19)vaccines received approval from regulatory bodies and were administered worldwide.Due to a low number of infections within China during that period,it became imperative to evaluate the vaccines’real-world effectiveness through international studies.To facilitate this,China CDC launched the COVID-19 Vaccines Evaluation Program(COVEP).This program formed research collaboration agreements with health institutes across five World Health Organization regions,addressing key questions about vaccine performance through ten cooperative agreements.The findings from COVEP projects reinforced confidence,both domestically and globally,in the effectiveness of the vaccines produced in China.Moreover,the outcomes observed internationally were frequently mirrored by later studies conducted within China.COVEP thus pioneered a novel approach for fostering cross-national research collaborations,addressing significant public health issues and exemplifying a framework for international cooperation.This approach is in line with the strategic objectives and other development efforts of China CDC’s national disease control and prevention initiatives.

Herbal drug discovery for the treatment of nonalcoholic fatty liver disease

Few medications are available for meeting the increasing disease burden of nonalcoholic fatty liver disease(NAFLD)and its progressive stage,nonalcoholic steatohepatitis(NASH).Traditional herbal medicines(THM)have been used for centuries to treat indigenous people with various symptoms but without clarified modern-defined disease types and mechanisms.In modern times,NAFLD was defined as a common chronic disease leading to more studies to understand NAFLD/NASH pathology and progression.THM have garnered increased attention for providing therapeutic candidates for treating NAFLD.In this review,a new model called"multiple organs-multiple hits"is proposed to explain mechanisms of NASH progression.Against this proposed model,the effects and mechanisms of the frequentlystudied THM-yielded single anti-NAFLD drug candidates and multiple herb medicines are reviewed,among which silymarin and berberine are already under U.S.FDA-sanctioned phase 4 clinical studies.Furthermore,experimental designs for anti-NAFLD drug discovery from THM in treating NAFLD are discussed.The opportunities and challenges of reverse pharmacology and reverse pharmacokinetic concepts-guided strategies for THM modernization and its global recognition to treat NAFLD are highlighted.Increasing mechanistic evidence is being generated to support the beneficial role of THM in treating NAFLD and anti-NAFLD drug discovery.

Fluoride Conversion Coating on Biodegradable AZ31B Magnesium Alloy

A fluoride conversion coating was successfully prepared on AZ31B magnesium alloy by chemical reaction in hydrofluoric acid. Morphologies, composition, bonding strength, corrosion properties, in vitro cytotoxicity and antibacterial properties of the coating were investigated, respectively. The scanning electron microscopy observations revealed a dense coating with some irregular pores. The thin-film X-ray diffraction analysis indicated that the coating was mainly composed of MgO and MgF2. The electrochemical impedance spectroscopy results showed that the fluoride conversion coating significantly improved the corrosion resistance of AZ31B. The hydroxyapatite formed on the surface of the fluoride coated AZ31 B after being immersed in the simulated blood plasma indicated the good bioactivity of the material. The in vitro cytotoxicity test showed that the fluoride coated AZ31B alloy was not toxic to BMMSCs （human bone marrow-derived mesenchymal stem cells）. It was also found that the fluoride coated AZ31 B alloy had antibacterial capability.

Inorganic nanomaterial lubricant additives for base fluids,to improve tribological performance:Recent developments

In this paper,we review recent research developments regarding the tribological performances of a series of inorganic nano-additives in lubricating fluids.First,we examine several basic types of inorganic nanomaterials,including metallic nanoparticles,metal oxides,carbon nanomaterials,and"other"nanomaterials.More specifically,the metallic nanoparticles we examine include silver,copper,nickel,molybdenum,and tungsten nanoparticles;the metal oxides include CuO,ZnO,Fe_(3)O_(4),TiO_(2),ZrO,Al_(2)O_(3),and several double-metal oxides;the carbon nanomaterials include fullerene,carbon quantum dots,carbon nanotubes,graphene,graphene oxides,graphite,and diamond;and the"other"nanomaterials include metal sulfides,rare-earth compounds,layered double hydroxides,clay minerals,hexagonal boron nitride,black phosphorus,and nanocomposites.Second,we summarize the lubrication mechanisms of these nano-additives and identify the factors affecting their tribological performance.Finally,we briefly discuss the challenges faced by inorganic nanoparticles in lubrication applications and discuss future research directions.This review offers new perspectives to improve our understanding of inorganic nano-additives in tribology,as well as several new approaches to expand their practical applications.

High efficiency ternary organic solar cells enabled by compatible dual-donor strategy with planar conjugated structures

Ternary organic solar cells(OSCs) have received extensive attention for improving the power conversion efficiency(PCE) of organic photovoltaics(OPVs). In this work, a novel donor material(ECTBD) consisting of benzodithiophene(BDT) central electron donor unit was developed and synthesized. The small molecular donor has the same central unit as PM6. The addition of ECTBD into PM6:Y6 system could improve the morphology of active blend layer. In addition, ECTBD showed good morphologically compatibility when blending with PM6:Y6 host, resulting in the improvement of fill factor and current density. As a result, the ternary devices based on PM6:ECTBD:Y6 ternary system achieved a highest PCE of 16.51% with fill factor of 76.24%, which was much higher than that of the binary devices(15.7%). Overall, this work provided an effective strategy to fabricate highly efficient ternary organic solar cells through design of the novel small molecular donor as the third component.

Association of COVID-19 Vaccination and Clinical Severity of Patients Infected with Delta or Omicron Variants——China,May 21,2021-February 28,2022

Summary What is already known about this topic?Compared with the international mRNA and adenovirus-vectored coronavirus disease 2019(COVID-19)vaccines,there is less real-world research data about breakthrough cases in people vaccinated with China-made COVID-19 vaccines.Analyses of clinical outcomes of breakthrough cases will be an important supplement to the clinical trial efficacy and observational effectiveness data of China-made COVID-19 vaccines.

Risk SNP-induced lncRNA-SLCCl drives colorectal cancer through activating glycolysis signaling

Long non-coding RNAs(lncRNAs)play key roles in colorectal carcinogenesis.Here,we aimed to identify the risk SNP-induced lncRNAs and to investigate their roles in colorectal carcinogenesis.First,we identified rs6695584 as the causative SNP in 1 q41 locus.The A>G mutation of rs6695584 created a protein-binding motif of BATF,altered the enhancer activity,and subsequently activated IncSLCCl expression.Further validation in two independent CRC cohorts confirmed the upregulation of IncSLCCl in CRC tissues,and revealed that increased IncSLCCl expression was associated with poor survival in CRC patients.Mechanistically,lncRNA-SLCCl interacted with AHR and transcriptionally activated HK2 expression,the crucial enzyme in glucose metabolism,thereby driving the glycolysis pathway and accelerating CRC tumor growth.The functional assays revealed that IncSLCCl induced glycolysis activation and tumor growth in CRC mediated by HK2.In addition,HK2 was upregulated in colorectal cancer tissues and positively correlated with IncSLCCl expression and patient survival.Taken together,our findings reveal a risk SNP-mediated oncogene lncRNA-SLCCl promotes CRC through activating the glycolysis pathway.

Wld^(S),Nmnats and axon degeneration-progress in the past two decades

A chimeric protein called Wallerian degeneration slow(Wld^(S))was first discovered in a spontaneous mutant strain of mice that exhibited delayed Wallerian degeneration.This provides a useful tool in elucidating the mechanisms of axon degeneration.Over-expression of WldS attenuates the axon degeneration that is associated with several neurodegenerative disease models,suggesting a new logic for developing a potential protective strategy.At molecular level,although Wld^(S)is a fusion protein,the nicotinamide mononucleotide adenylyl transferase 1(Nmnat1)is required and sufficient for the protective effects of Wld^(S),indicating a critical role of NAD biosynthesis and perhaps energy metabolism in axon degeneration.These findings challenge the proposed model in which axon degeneration is operated by an active programmed process and thus may have important implication in understanding the mechanisms of neurodegeneration.In this review,we will summarize these recent findings and discuss their relevance to the mechanisms of axon degeneration.

Effectiveness of DTaP Against Pertussis in≤2-Year-Old Children—Linyi Prefecture,Shandong Province,China,2017–2019

Summary What is already known about this topic?Vaccine effectiveness(VE)is positively correlated with the number of administered co-purified diphtheria,tetanus,and acellular pertussis vaccine(DTaP)doses.A matched case-control study conducted in Zhongshan City revealed that the co-purified DTaP VE against pertussis-related illnesses in children aged 4–11 months was 42%for one dose,88%for two doses,and 95%for three doses,respectively.What is added by this report?The results of this study contribute to the current body of research.We found that the VE of co-purified DTaP against pertussis-related illness and hospitalization increased substantially,ranging from 24%–26%after one dose to 86%–87%after four doses.