Synthesis of mordenite by solvent-free method and its application in the dimethyl ether carbonylation reaction

Mordenite with different Si/Al ratios were synthesized by solvent-free method and used for dimethyl ether(DME)carbonylation reaction.The influence of Si/Al ratio in the feedstock on the structure,porosity and acid sites were systematically investigated.The characterization results showed that with the increase of Si/Al ratio in the feedstock,part of silicon species fail to enter the skeleton and the specific surface area and pore volume of the samples decreased.The amount of weak acid and medium strong acid decreased alongside with the increasing Si/Al ratio,and the amount of strong acid slightly increased.The Al atoms preferentially enter the strong acid sites in the 8 member ring(MR)channel during the crystallization process.The high Si/Al ratio sample had more acid sites located in the 8 MR channel,leading to more active sites for carbonylation reaction and higher catalytic performance.Appropriately increasing the Si/Al ratio was beneficial for the improvement of carbonylation reaction activity over the mordenite(MOR)catalyst.

Interactive effects of soil temperature and moisture on soil N mineralization in a Stipa krylovii grassland in Inner Mongolia, China

Determining soil N mineralization response to soil temperature and moisture changes is challenging in the field due to complicated effects from other factors. In the laboratory, N mineralization is highly dependent on temperature, moisture and sample size. In this study, a laboratory incubation experiment was carefully designed and conducted under controlled conditions to examine the effects of soil temperature and moisture on soil N mineralization using soil samples obtained from the Stipa krylovii grassland in Inner Mongolia, China. Five temperature（i.e. 9℃, 14℃, 22℃, 30℃ and 40℃） and five moisture levels（i.e. 20%, 40%, 60%, 80% and 100% WHC, where WHC is the soil water holding capacity） were included in a full-factorial design. During the 71-day incubation period, microbial biomass carbon（MBC）, ammonium nitrogen（NH4 ^＋-N） and nitrate nitrogen（NO3^--N） were measured approximately every 18 days; soil basal respiration for qCO2 index was measured once every 2 days（once a week near the end of the incubation period）. The results showed that the mineral N production and net N mineralization rates were positively correlated with temperature; the strongest correlation was observed for temperatures between 30℃ and 40℃. The relationships between moisture levels and both the mineral N production and net N mineralization rates were quadratic. The interaction between soil temperature and moisture was significant on N mineralization, i.e. increasing temperatures（moisture） enhanced the sensitivity of N mineralization to moisture（temperature）. Our results also showed a positive correlation between the net nitrification rate and temperature, while the correlation between the NH4 ^＋-N content and temperature was insignificant. The net nitrification rate was negatively correlated with high NH4 ^＋-N contents at 80%–100% WHC, suggesting an active denitrification in moist conditions. Moreover, qCO2 index was positively correlated with temperature, especially at 80% WHC. With a low net nitrification rate and high soil basal respiration rate, it was likely that the denitrification concealed the microbial gross mineralization activity; therefore, active soil N mineralization occurred in 60%–80% WHC conditions.

Nutrient Composition of Different Foxtail Millet Seeds

Ten millet cultivars from China and abroad were analyzed for their crude fat, amylose and amylopectin, crude protein and amino acid content. A wide variation was observed in amylopectin contain, ranging from 54.47% to 69.26%, while amylose content ranged from 11.26% to 23.22%. The average crude fat in all cultivates was 3.46%, and most cultivates ranged from 3.1% to 3.7%. Protein contents ranged from 8.61% to 15.54% with a mean value of 11.94%. For amino acid composition, the ten cultivates were particularly rich in leucine, and the mean was 34.57 mg/g. The millet cultivars were also high in glycine, glutamic acid and cysteine. Millet was known to be limiting in the essential amino lysine, and the mean was 5.18 mg/g. Other amino acids, tyrosine, histidine and arginine were also very low in the ten cultivars. In general, significant nutrient composition differences were observed between the different millet cultivars, and A2 （a kind of mother line of the hybrid millet） and hybrid millet registered a higher level of protein and amino acid composition which would be useful in millet breeding.

Expansion of the South China Sea basin:Constraints from magnetic anomaly stripes,sea floor topography,satellite gravity and submarine geothermics

The widely distributed E-W-trending magnetic anomaly stripes in the central basin and the N-Etrending magnetic anomaly stripes in the southwest sub-basin provide the most important evidence for Neogene expansion of the South China Sea.The expansion mechanism remains,however,controversial because of the lack of direct drilling data,non-systematic marine magnetic survey data,and irregular magnetic anomaly stripes with two obvious directions.For example,researchers have inferred different ages and episodes of expansion for the central basin and southwest sub-basin.Major controversy centers on the order of basinal expansion and the mechanism of expansion for the entire South China Sea basin.This study attempts to constrain these problems from a comprehensive analysis of the seafloor topography,magnetic anomaly stripes,regional aeromagnetic data,satellite gravity,and submarine geothermics.The mapped seafloor terrain shows that the central basin is a north-south rectangle that is relatively shallow with many seamounts,whereas the southwest sub-basin is wide in northeast,gradually narrows to the southwest,and is relatively deeper with fewer seamounts.Many magnetic anomaly stripes are present in the central basin with variable dimensions and directions that are dominantly EWtrending,followed by the NE-,NW- and NS-trending.Conversely such stripes are few in the southwest sub-basin and mainly NE-trending.Regional magnetic data suggest that the NW-trending Ailaoshan-Red River fault extends into the South China Sea,links with the central fault zone in the South China Sea,which extends further southward to Reed Tablemount.Satellite gravity data show that both the central basin and southwest sub-basin are composed of oceanic crust.The Changlong seamount is particularly visible in the southwest sub-basin and extends eastward to the Zhenbei seamount.Also a low gravity anomaly zone coincides with the central fault zone in the sub-basin.The submarine geothermic distribution demonstrates that the southwest sub-basin has a higher geothermal value than the central basin,and that the central fault zone is defined by a low thermal anomaly.This study suggests that NW-SE expansion of the southwest subbasin is later than the N-S expansion of the central basin with the sub-basin extending into the central basin and with both expansions ending at the same time.The expansion of southwestern sub-basin,similar to the Japanese Sea,is likely caused by left-lateral strike slip on the central fault zone in the South China Sea,which may have significance for finding oil and gas in this region.

A New Exploration of Practical Teaching Reform in the Department of Plant Protection of Hebei North University

In view of the existing problems in the practical teaching of Plant Protection majors,such as more teaching contents,less comprehensive and innovative contents,disorganized practical teaching system,lenient assessment,insufficient experimental teaching facilities,insufficient practical teaching sites,and lack of continuity of practical teaching contents.The practical teaching of plant protection majors should adopt“open”practice teaching methods in terms of laboratory construction,innovative ability cultivation,practical teaching content highlighting comprehensive and innovative,and practical teaching time.The results of the survey on college graduates and enterprises show that under the“open”practice mode,Plant Protection students will have better overall performance.

Reform and Research on the Combination of Production and Education in Plant Protection under the Background of Transformation and Development

Plant Protection is an agricultural discipline with strong theoretical and practical significance.In order to adapt to the development direction of the society during the transition period and the need for professional talents,the researchers have discussed the teaching mode of the plant protection major from various perspectives of the teaching practice.Through the integration of teaching content and knowledge the overall structure of the course is being made clearer and reasonable;The use of different teaching methods has stimulated the initiative of students and achieved remarkable teaching results;The creativity and practical ability of students have been significantly improved;And the examination and evaluation system has been improved,thereby students’performance can be truly reflected.Through the reform and research of plant protection industry-academia and practical teaching,a feasible way is proposed for the combination of industry-academia and the cultivation of practical talents.

USP25 promotes hepatocellular carcinoma progression by interacting with TRIM21 via the Wnt/β-catenin signaling pathway

Background:Hepatocellular carcinoma(HCC)is one of the most common malignant tumors in the world.The ubiquitin-specific peptidase 25(USP25)protein has been reported to participate in the development of several cancers.However,few studies have reported its association with HCC.In this study,we aimed to investigate the function and mechanism of USP25 in the progression of HCC.Methods:We analyzed USP25 protein expression in HCC based on The Cancer Genome Atlas(TCGA)and International Cancer Genome Consortium(ICGC)database cohorts.Then,we constructed USP25-overexpressing and USP25-knockdown HepG2,MHCC97H,and L-O2 cells.We detected the biological function of USP25 by performing a series of assays,such as Cell Counting Kit-8(CCK-8),colony formation,transwell,and wound healing assays.Western blotting and quantitative real-time polymerase chain reaction(qRT-PCR)analyses were performed to detect the interaction between USP25 and the Wnt/β-catenin signaling pathway.The relationship between USP25 and tripartite motif-containing 21(TRIM21)was assessed through mass spectrometry and co-immunoprecipitation(Co-IP)analysis.Finally,we constructed a mouse liver cancer model with the USP25 gene deletion to verify in vivo role of USP25.Results:USP25 was highly expressed in HCC tissue and HCC cell lines.Importantly,high expression of USP25 in tissues was closely related to a poor prognosis.USP25 knockdown markedly reduced the proliferation,migration,and invasion of HepG2 and MHCC97H cells,whereas USP25 overexpression led to the opposite effects.In addition,we demonstrated that USP25 interacts with TRIM21 to regulate the expression of proteins related to epithelial-mesenchymal transition(EMT;E-cadherin,N-cadherin,and Snail)and the Wnt/β-catenin pathway(β-catenin,Adenomatous polyposis coli,Axin2 and Glycogen synthase kinase 3 beta)and those of their downstream proteins(C-myc and Cyclin D1).Finally,we verified that knocking out USP25 inhibited tumor growth and distant metastasis in vivo.Conclusions:In summary,our data showed that USP25 was overexpressed in HCC.USP25 promoted the proliferation,migration,invasion,and EMT of HCC cells by interacting with TRIM21 to activate theβ-catenin signaling pathway.

层流冷却传热系数对金属物料温度场的影响

层流冷却的冷却强度决定着金属物料微观组织结构,从而影响产品的性能,而传热系数直接影响着冷却强度的大小。本工作提出了一种获得层流冷却传热系数的方法,通过工艺分析得到其分布形式为以喷头为中心由半波正弦和直线构成的分段函数,给出了通过结构参数、运行参数和实验数据获得函数特征参数的方法。以实验台验证了该方法的准确性,同时分析了特征参数变化对金属物料温度场的影响规律。结果表明,振幅增加1W/(m^(2)·K),金属物料表面温度相对下降量在最后一个区域达到最大值,为-0.36m^(2)·K^(2)/W,断面温差最大相对变化量为0.07m^(2)·K^(2)/W;周期减小1s,金属物料表面温度相对增加量在最后一个区域达到最大值,为13.24K/s,断面温差呈现周期性变化,变化范围为-2.5~0 K/s。

Regulation of signaling pathways in hair follicle stem cells

Hair follicle stem cells(HFSCs)reside in the bulge region of the outer root sheath of the hair follicle.They are considered slow-cycling cells that are endowed with multilineage differentiation potential and superior proliferative capacity.The normal morphology and periodic growth of HFSCs play a significant role in normal skin functions,wound repair and skin regeneration.The HFSCs involved in these pathophysiological processes are regulated by a series of cell signal transduction pathways,such as lymphoid enhancer factor/T-cell factor,Wnt/β-catenin,transforming growth factor-β/bone morphogenetic protein,Notch and Hedgehog.The mechanisms of the interactions among these signaling pathways and their regulatory effects on HFSCs have been previously studied,but many mechanisms are still unclear.This article reviews the regulation of hair follicles,HFSCs and related signaling pathways,with the aims of summarizing previous research results,revealing the regulatory mechanisms of HFSC proliferation and differentiation and providing important references and new ideas for treating clinical diseases.

A regulatory perspective on recombinant collagen-based medical devices

As a class of novel biomaterials manufactured by synthetic biology technologies,recombinant collagens are candidates for a variety of medical applications.In this article,a regulatory scientific perspective on recombinant collagens and their medical devices is presented with a focus on the definition,translation,classification and technical review.Recombinant collagens are categorized as recombinant human collagen,recombinant humanized collagen and recombinant collagen-like protein,as differentiated by specific compositions and structures.Based on their intended uses and associated risks,recombinant collagen-based medical devices are generally classified as Class Ⅱ or Ⅲ in China.The regulatory review of recombinant collagen-based medical devices aims to assess their safety and efficacy demonstrated by scientific evidences generated from preclinical and clinical evaluations.Taken together,opportunities as well as challenges for their future clinical translation of recombinant collagen-based medical devices abound,which highlights the essential role of regulatory science to provide new tools,standards,guidelines and methods to evaluate the safety and efficacy of medical products.

Regulatory considerations for animal studies of biomaterial products

Animal studies play a vital role in validating the concept,feasibility,safety,performance and efficacy of biomaterials products during their bench-to-clinic translation.This article aims to share regulatory considerations for animal studies of biomaterial products.After briefly emphasizing the importance of animal studies,issues of animal studies during biomaterial products’translation are discussed.Animal studies with unclear purposes,flawed design and poor reporting quality could significantly reduce the translation efficiency and create regulatory challenges.Regulatory perspectives on the purpose,principle,quality and regulatory science of animal studies are also presented.Animal studies should have clear purposes,follow principles of 3R+DQ(replacement,reduction,refinement,design and quality)and execute under an efficiently operating quality management system.With the advancement of regulatory science,National Medical Products Administration of China has been developing a series of standards and guidance documents on animal studies of medical devices.Case studies of making decisions on whether to conduct animal studies are provided in the end with drug-eluting stents as examples.In summary,animal studies of biomaterial products should pay close attention to the rationale,design and quality in order to achieve their purposes.

Integrating global socio-economic influences into a regional land use change model for China

With rapid economic development and urba- nization, land use in China has experienced huge changes in recent years; and this will probably continue in the future. Land use problems in China are urgent and need further study. Rapid land-use change and economic development make China an ideal region for integrated land use change studies, particularly the examination of multiple factors and global-regional interactions in the context of global economic integration. This paper presents an integrated modeling approach to examine the impact of global socio-economic processes on land use changes at a regional scale. We develop an integrated model system by coupling a simple global socio-economic model （GLOBFOOD） and regional spatial allocation model （CLUE）. The model system is illustrated with an application to land use in China. For a given climate change, population growth, and various socio-economic situations, a global socio-economic model simulates the impact of global market and economy on land use, and quantifies changes of different land use types. The land use spatial distribution model decides the type of land use most appropriate in each spatial grid by employing a weighted suitability index, derived from expert knowledge abot^t the ecosystem state and site conditions. A series of model simulations will be conducted and analyzed to demonstrate the ability of the integrated model to link global socio- economic factors with regional land use changes in China. The results allow an exploration of the future dynamics of land use and landscapes in China.

Dehydrative Beckmann rearrangement and the following cascade reactions

The Beckmann rearrangement has been predominantly studied for the synthesis of amide and lactam.By strategically using the in situ generated Appel’s salt or Mitsunobu’s zwitterionic adduct as the de-hydrating agent,a series of Beckmann rearrangement and following cascade reactions have been devel-oped herein.The protocol allows the conversion of various ketoximes into amide,thioamide,tetrazole and imide products in modular procedures.The generality and tolerance of functionalities of this method have been demonstrated.