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Particuology 2023年第4期75卷 165-176页

作者： Xiuying Yao jun xu Yiping Fan Chunxi Lu Fuwei Sun State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China China Kunlun Contracting&Engineering Co LtdBeijing100037China

With the development of current energy economy,it is necessary to improve the product distribution of fluid catalytic cracking process,which is achieved by a riser reactor with double-level of nozzles.The new riser is constructed by adding a level of secondary nozzle 0.5 m below the main nozzle of traditional riser.This paper investigates the gas-solids flow and oil-catalyst matching feature based on the optical fiber and tracer technologies.According to the distribution of solids holdup,particle velocity and dimen-sionless jet concentration,the feedstock injection zone can be divided into the upstream flow control region,the main flow control region,and the secondary flow control region in the radial direction.The size of the regions is changed by the jet gas velocity and axial height.There is a poor match of secondary nozzle jet to particles below the main nozzle.The jet gas from secondary nozzles can improve the matching effect of oil-catalyst near the wall and reduce the probability of coking above the main nozzle.

关键词： Gas-solids flow Matching Feed injection zone Double-level nozzles Riser

Alkynyl-anchored silver nanoclusters in lanthanide metal-organic framework for luminescent thermometer and CO_(2) cycloaddition

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Nano Research 2023年第5期16卷 7452-7458页

作者： Jing-Wen Hu Wan-Zhen Qiao jun-jun Sun jun xu Xi-Yan Dong Chong Zhang Shuang-Quan Zang College of Chemistry and Chemical Engineering Henan Polytechnic UniversityJiaozuo 454000China College of Chemistry Zhengzhou UniversityZhengzhou 450001China College of Materials Science and Engineering Henan University of TechnologyZhengzhou 450001China

In this study,an alkynyl-modified aromatic dicarboxylic acid bifunctional ligand was selected to construct lanthanide compound{[Eu_(4)(ebdc)_(6)(4,4-bpy)_(0.5)(H_(2)O)_(4.5)]·(C_(2)H_(5)OH)_(1.25)(H_(2)O)}_(n)(Eu-MOF,H_(2)ebdc=5-ethynyl-isophthalic acid,4,4-bpy=4,4-bipyridine,MOF=metal-organic framework),of which the uncoordinated alkynyl group would be used to anchor silver nanoclusters(Ag NCs).The Eu-MOF exhibits double emission peaks,located at 492 and 611 nm,respectively,in which the high-energy blue emission is associated with alkynyl-modified ligand while the low-energy red emission belongs to characteristic emission of Eu3+,indicating that ligands can effectively sensitize Eu3+luminescence.The intensity ratio of the dual emission fluorescence peaks of Eu-MOF displays a good linear relationship with temperature,which realizes the detection function in the low temperature region of 75–275 K,the thermal sensitivity reaches 1.5398%·K^(−1).After anchoring the Ag NCs,the high-energy blue emission is significantly quenched,indicating that the Ag NCs are indeed confined into the framework and interact with the alkynyl group,and thus change the overall electronic distribution.This is the first case of anchoring Ag NCs by a luminescent Eu-MOF and studying nanocluster loading by using spectroscopic properties.In addition,the Ag NCs@Eu-MOF also shows a good catalytic activity for cycloaddition reaction from CO_(2)and epoxides.This study not only provides ideas for exploring the changes in optical properties of luminescent MOFs and Ag NCs caused by confinement effect,but also expands their potential applications in various fields.

关键词： silver nanoclusters confinement effect lanthanide metal-organic framework(MOF) ratiometric fluorescence thermometer CO_(2)cycloaddition

Water modeling on fluid flow and mixing phenomena in a BOF steelmaking converter

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Journal of Iron and Steel Research(International) 2024年第3期31卷 595-607页

作者： Xin-yu Cai Hao-jian Duan Ding-han Li Anjun xu Li-feng Zhang School of Metallurgical and Ecological Engineering University of Science and Technology Beijing(USTB)Beijing 100083China School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China

A 1∶8 physical water model was constructed to investigate the fluid flow and mixing phenomena in the basic oxygen furnace(BOF)converter.The particle image velocimetry was employed to measure the velocity distribution of the bath and the high-speed camera was applied to capture the cavity shape in the combined blowing BOF converter.The mixing time for varied operating conditions was measured by the stimulus-response approach.The cavity depth increased with the decrease in the lance height and the increase in the top gas flow rate while the bottom blowing gas had little influence on the cavity depth.The minimum cavity depth was obtained under the condition of a 69.8 m^(3)/h top gas flow rate,a 287.5 mm lance height and a 0.93 m^(3)/h bottom blowing gas flow rate,which was 161.2 mm.The mixing time decreased as the lance height decreased and the top blowing gas flow rate increased.The mixing time was first decreased and then increased with the increase in the bottom gas flow rate.With the condition of 69.8 m^(3)/h gas flow rate of top blowing,the 287.5 mm lance height and the 0.93 m^(3)/h gas flow rate of bottom blowing,the mixing time in the converter was 48.65 s.The empirical formula between the stirring power and the mixing time in the converter was calculated.

关键词： Water model Fluid flow Particle image velocimetry Mixing time BOF converter

The role of targeting protein for Xklp2 in tumorigenesis of hepatocellular carcinoma

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Hepatobiliary & Pancreatic Diseases International 2023年第4期22卷 418-422页

作者： Ting Li Lu-Jian Zhu An-Min Huang Yi-Feng Wei jun xu Ye-Jin xu Department of Infectious Diseases Jinhua Municipal Central HospitalJinhua 321000China School of the First Clinical Medical Sciences(School of Information and Engineering) Wenzhou Medical UniversityWenzhou 325035China

To the Editor:Hepatocellular carcinoma(HCC)is a prevalent form of gastrointestinal malignancies.The current combination of immunotherapy and other treatments improves overall survival compared to conventional therapies,but the immunosuppressive microenvironment of HCC is a significant barrier to the efficacy of immunothera-peutic drugs[1].Tumor immune escape is promoted by interactions among immunosuppressive cells,including tumor-associated macrophages,marrow-derived suppressor cells,tumor-associated neutrophils,cancer-associated fibroblasts,and tumor-infiltrating Tregs[2].

关键词： drugs suppressor hepatocellular

Serine and arginine rich splicing factor 1:a potential target for neuroprotection and other diseases

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Neural Regeneration Research 2023年第7期18卷 1411-1416页

作者： Ana M.Sandoval-Castellanos Anushka Bhargava Min Zhao jun xu Ke Ning Sheffield Institute of Translational Neuroscience SITraNThe University of SheffieldSheffieldUK Department of Ophthalmology&Vision Science and Department of DermatologyInstitute for Regenerative CuresUniversity of California at DavisSchool of MedicineSacramentoCAUSA East Hospital Tongji University School of MedicineShanghaiChina

Alternative splicing is the process of producing variably spliced mRNAs by choosing distinct combinations of splice sites within a messenger RNA precursor.This splicing enables mRNA from a single gene to synthesize different proteins,which have different cellular properties and functions and yet arise from the same single gene.A family of splicing factors,Serine-arginine rich proteins,are needed to initiate the assembly and activation of the spliceosome.Serine and arginine rich splicing factor 1,part of the arginine/serine-rich splicing factor protein family,can either activate or inhibit the splicing of mRNAs,depending on the phosphorylation status of the protein and its interaction partners.Considering that serine and arginine rich splicing factor 1 is either an activator or an inhibitor,this protein has been studied widely to identify its various roles in different diseases.Research has found that serine and arginine rich splicing factor 1 is a key target for neuroprotection,showing its promising potential use in therapeutics for neurodegenerative disorders.Furthermore,serine and arginine rich splicing factor 1 might be used to regulate cancer development and autoimmune diseases.In this review,we highlight how serine and arginine rich splicing factor 1 has been studied concerning neuroprotection.In addition,we draw attention to how serine and arginine rich splicing factor 1 is being studied in cancer and immunological disorders,as well as how serine and arginine rich splicing factor 1 acts outside the central or peripheral nervous system.

关键词： alternative splicing autoimmune disorders cancer hypertension mRNA neuroprotection splicing factors SRSF1

Impact of soluble organic matter and particulate organic matter on anammox system: Performance, microbial community and N_(2)O production

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Journal of Environmental Sciences 2023年第2期124卷 146-155页

作者： Yingying He HongyuMao Jacek Makinia Jakub Drewnowski Bing Wu jun xu Li Xie Xi Lu Key Laboratory of Yangtze Water Environment Ministry of EducationTongji UniversityShanghai 200092China Faculty of Civil and Environmental Engineering Gdansk University of TechnologyGdansk 80-233Poland

In this study,the effects of soluble readily biodegradable COD(sCOD)and particulate slowly biodegradable COD(pCOD)on anammox process were investigated.The results of the longterm experiment indicated that a low sCOD/N ratio of 0.5 could accelerate the anammox and denitrification activity,to reach as high as 84.9%±2.8%TN removal efficiency.Partial denitrification-anammox(PDN/anammox)and denitrification were proposed as the major pathways for nitrogen removal,accounting for 91.3% and 8.7% of the TN removal,respectively.Anammox bacteria could remain active with high abundance of anammox genes to maintain its dominance.Candidatus Kuenenia and Thauera were the predominant genera in the presence of organic matter.Compared with sCOD,batch experiments showed that the introduction of pCOD had a negative effect on nitrogen removal.The contribution of denitrification to nitrogen removal decreased from approximately 14%to 3% with increasing percentage of pCOD.In addition,the analysis result of the process data using an optimized ASM1 model indicated that high percentage of pCOD resulted in serious N_(2)O emission(the peak value up to 0.25mg N/L),whichwas likely due to limited mass diffusion and insufficient available carbon sources for denitrification.However,a high sCOD/N ratio was beneficial for alleviating N_(2)O accumulation.

关键词： Anammox Partial denitrification Microbial community structure Carbon composition Nitrous oxide production

Obstructive sleep apnea aggravates neuroinflammation and pyroptosis in early brain injury following subarachnoid hemorrhage via ASC/HIF-1α pathway

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Neural Regeneration Research 2022年第11期17卷 2537-2543页

作者： jun xu Qian Li Chen-Yu xu Shan Mao Jia-Jia Jin Wei Gu Ying Shi Chun-Fang Zou Liang Ye Department of Respiration Nanjing First HospitalNanjing Medical UniversityNanjingJiangsu ProvinceChina Department of Respiration Nanjing Yuhua HospitalYuhua Branch of Nanjing First HospitalNanjingJiangsu ProvinceChina

Obstructive sleep apnea can worsen the prognosis of subarachnoid hemorrhage.Howeve r,the underlying mechanism remains unclear.In this study,we established a mouse model of subarachnoid hemorrhage using the endovascular perforation method and exposed the mice to intermittent hypoxia for 8 hours daily for 2 consecutive days to simulate sleep apnea.We found that sleep apnea aggravated brain edema,increased hippocampal neuron apoptosis,and worsened neurological function in this mouse model of subarachnoid hemorrhage.Then,we established an in vitro HT-22 cell model of hemin-induced subarachnoid hemorrhage/intermittent hypoxia and found that the cells died,and lactate dehydrogenase release increased,after 48 hours.We further investigated the underlying mechanism and found that sleep apnea increased the expression of hippocampal neuroinflammatory factors interleukin-1β,interleukin-18,inte rleukin-6,nuclear factorκB,pyro ptosis-related protein caspase-1,pro-caspase-1,and NLRP3,promoted the prolife ration of astrocytes,and increased the expression of hypoxia-inducible factor 1αand apoptosis-associated speck-like protein containing a CARD,which are the key proteins in the hypoxia-inducible factor 1α/apoptosis-associated speck-like protein containing a CARD signaling pathway.We also found that knockdown of hypoxia-inducible factor 1αexpression in vitro greatly reduced the damage to HY22 cells.These findings suggest that sleep apnea aggravates early brain injury after subarachnoid hemorrhage by aggravating neuroinflammation and pyroptosis,at least in part through the hypoxia-inducible factor 1α/apoptosis-associated speck-like protein containing a CARD signaling pathway.

关键词： apoptosis associated speck like protein containing a CARD early brain injury hypoxia-inducible factor 1α nucleotide-binding domain and leucine-rich repeat protein 3 obstructive sleep apnea pyroptosis neuroinflammation subarachnoid hemorrhage

Application of Langlois' reagent(NaSO_(2)CF_(3)) in C–H functionalisation

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Chinese Chemical Letters 2022年第3期33卷 1227-1235页

作者： Jiabin Shen jun xu Lei He Chenfeng Liang Wanmei Li College of Material Chemistry and Chemical EngineeringKey Laboratory of Organosilicon Chemistry and Material TechnologyMinistry of EducationHangzhou Normal UniversityHangzhou 311121China

The process of selectively introducing a CF_(3) group into an organic molecule using inexpensive, stable, and solid sodium trifluoromethanesulfinate has rapidly advanced in recent years to become an eco-friendly method used by organic chemists to synthesize various natural and bioactive molecules. This review focuses on advances made within the last five years regarding C-H functionalisation, namely thermochemical C(sp^(2))-H (thio)trifluoromethylations, photochemical C(sp^(2))-H trifluoromethylations, and electrochemical C(sp^(2))-H trifluoromethylations, using Langlois’ reagent (NaSO_(2)CF_(3)).

关键词： Trifluoromethylation Langlois’reagent Reaction mechanism Synthetic method C–H activation

New Kinetics Equation for Stress Relaxation of Semi-crystalline Polymers below Glass Transition Temperature

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Chinese Journal of Polymer Science 2022年第12期40卷 1662-1669,I0010页

作者： Cheng Zhang Li-Hai Cai Bao-Hua Guo Bing Miao jun xu Advanced Materials Laboratory of Ministry of Education Department of Chemical EngineeringTsinghua UniversityBeijing 100084China Tsinghua Innovation Center in Dongguan Dongguan 523808China Center of Materials Science and Optoelectronics Engineering College of Materials Science and Opto-Electronic TechnologyUniversity of Chinese Academy of SciencesBeijing 100049China

The stress relaxation of semi-crystalline nylon 1010 cannot be fitted by the Kohlrausch-Williams-Watts formula when the experiments were performed at pre-yielding regime below the glass transition temperature.We study this problem and identify the two-step mechanism of stress relaxation.At short time scale,relaxation is fast,dominated by stress biased thermal fluctuation with a fixed short-range length scale(activation volume).At long time scale,relaxation is slow due to the emergence of a cooperative long-range length scale determined by the stress fluctuation.The cooperative length scale is proportional to the reciprocal of stress and the amplitude of stress fluctuation is the product of stress and activation volume.Based on this two-step mechanism,we propose a new kinetics equation to capture the stress relaxation effectively,where the short time relaxation is described by an Eyring-like local activation and the long-time relaxation is captured by a cooperative excitation process resorting to an extension from the random first order transition theory.Our equation fits the experimental data well and can serve as a model to guide the related experiments of relaxation processes in crystalline solids.

关键词： Stress relaxation Semi-crystalline polymers Kohlrausch-Williams-Watts(KWW)equation Random first order transition(RFOT)theory

Treatment of hyperkalemic emergencies

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World Journal of Emergency Medicine 2022年第3期13卷 232-236页

作者： Yao Wu Yang-yang Fu Hua-dong Zhu jun xu Joseph Harold Walline Emergency Department State Key Laboratory of Complex Severe and Rare DiseasesPeking Union Medical College HospitalChinese Academy of Medical Science and Peking Union Medical CollegeBeijing 100730China Centre for the Humanities and Medicine the University of Hong KongHong KongChina

Hyperkalemic emergency(HE)refers to life-threatening hyperkalemia consisting of a high serum potassium level with severe complications(e.g.,dysrhythmias,cardiac arrest,or myopathy).^([1])Hyperkalemic emergencies(HEs)a... 详细信息

关键词： cardiac potassium arrest