Design strategies and structure‐performance relationships of heterogeneous catalysts for selective hydrogenation of 1,3‐butadiene

Selective hydrogenation of 1,3‐butadiene is an essential process in the upgrading of the crude C4 cut from the petroleum chemical sector.Catalyst design is crucial to achieve a virtually alkadiene‐free product while avoiding over‐hydrogenating valuable olefins.In addition to the great industrial relevance,this demanding selectivity pattern renders 1,3‐butadiene hydrogenation a widely used model reaction to discriminate selective hydrogenation catalysts in academia.Nonetheless,critical reviews on the catalyst development are extremely lacking in literature.In this review,we aim to provide the reader an in‐depth overview of different catalyst families,particularly the precious metal‐based monometallic catalysts(Pd,Pt,and Au),developed in the last half century.The emphasis is placed on the development of new strategies to design high‐performance architectures,the establishment of structure‐performance relationships,and the reaction and deactivation mechanisms.Thrilling directions for future optimization of catalyst formulations and engineering aspect are also provided.

M/C_(3)N_(4)/AC(M=Au,Pt,Ru)‐catalyzed acetylene coupling with ethylene dichloride:How effective are the bifunctionalities?

Acetylene coupling with ethylene dichloride,which uses both coal and oil resources,is attractive for sustainable PVC manufacturing.Herein,highly active and stable carbon nitride‐based catalysts were developed by a novel pre‐oxidation‐pyrolysis process,affording unprecedented dehydrochlorination activity with good durability.The best‐performing system was further modified with different precious metals(Au,Pt,and Ru)to promote the hydrochlorination chemistry between the in‐situ formed hydrogen chloride and acetylene co‐feed.The presence of metal centers intensifies the hydrochlorination activity but weakens the dehydrochlorination ability due to competitive adsorption between the two reactants at the metal sites.Superior coupling performance was achieved over C_(3)N_(4)/AC and single‐atom Au/C_(3)N_(4)/AC catalysts in cascade reactors.Our results strongly suggest that dehydrochlorination is an essential step in the coupling reaction,and the activation of acetylene and ethylene dichloride molecules requires different active sites that should be engineered in future work.

Selective hydrogenation of 1,3-butadiene on iridium nanostructures:Structure sensitivity, host effect, and deactivation mechanism

A systematic study on the structure sensitivity,host effect,and the deactivation mechanism of Ircatalyzed selective hydrogenation of 1,3-butadiene,a key process in the purification of alkadiene for the upgrading of C4 cut,is presented by coupling steady-state catalytic testing,in-depth characterization,kinetic evaluation,and density functional theory calculations.We reveal that:(i) 1,3-Butadiene hydrogenation on iridium is structure-sensitive with the optimal particle size of about 2 nm,and the H_(2) dissociation energy is a reliable activity descriptor;(ii) The nature of the NC hosts exerts a critical impact on the catalytic performance,and balanced nitrogen content and speciation seem key for the optimized performance;and (iii) Different deactivation mechanisms occur:fouling by coke deposition on the catalysts with a high N:C ratio (>1),and site blockage due to the competitive adsorption between 1-butene/cis-2-butene and 1,3-butadiene.These molecular insights provide valuable guidelines for the catalyst design in selective hydrogenations.

Assembly of N-and P-functionalized carbon nanostructures derived from precursor-defined ternary copolymers for high-capacity lithiumion batteries

Synthesis of new carbon nanostructures with tunable properties is vital for precisely regulating electrochemical performance in the wide applications.Herein,we report a novel approach for the oxidative polymerization of N-and P-bearing copolymers from the self-assembly of three different monomers(aniline,pyrrole,and phytic acid),and further prepare the respective carbon nanostructures with relatively consistent N dopant(6.2%–8.0%,atom)and varying P concentrations(0.4%–2.8%,atom)via controllable pyrolysis.The impacts of phytic acid addition on the compositional,structural,and morphological evolution of the copolymers and the resulting nanocarbons are well studied through a spectrum of characterizations including N2 sorption,Fourier transform infrared spectroscopy,gel permeation chromatograph,scanning/transmission electron microscopy,and X-ray photoelectron spectroscopy.Gradual fragmentation of the nanosphere structures is evidenced with increasing addition of phytic acid,leading to different nanostructures from hollow nanospheres to 3D aggregates.Nanocarbons decorated with N and P dopants from pyrolysis are further utilized as anode materials in lithium-ion batteries,demonstrating enhanced electrochemical performance,i.e.,a reversible capacity of 380 mA
h
g^(-1)at 2 A
g^(-1)for NPC-0.5 during 200 cycles.The superior performance originates from the balanced porosity,and appropriate concentrations of P and pyrrolic N,thus pointing the direction for designing high-performance anode materials.

Soft Mesoporous Organosilica Nanoplatforms Improve Blood Circulation,Tumor Accumulation/Penetration,and Photodynamic Efficacy

To date,the ability of nanoplatforms to achieve excellent therapeutic responses is hindered by short blood circulation and limited tumor accumulation/penetration.Herein,a soft mesoporous organosilica nanoplatform modified with hyaluronic acid and cyanine 5.5 are prepared,denoted SMONs-HA-Cy5.5,and comparative studies between SMONs-HA-Cy5.5(24.2 MPa)and stiff counterparts(79.2 MPa)are conducted.Results indicate that,apart from exhibiting a twofold increase in tumor cellular uptake,the soft nanoplatforms also display a remarkable pharmacokinetic advantage,resulting in considerably improved tumor accumulation.Moreover,SMONs-HA-Cy5.5 exhibits a significantly higher tumor penetration,achieving 30-μm deeper tissue permeability in multicellular spheroids relative to the stiff counterparts.Results further reveal that the soft nanoplatforms have an easier extravasation from the tumor vessels,diffuse farther in the dense extracellular matrix,and reach deeper tumor tissues compared to the stiff ones.Specifically,the soft nanoplatforms generate a 16-fold improvement(43 vs.2.72μm)in diffusion distance in tumor parenchyma.Based on the significantly improved blood circulation and tumor accumulation/penetration,a soft therapeutic nanoplatform is constructed by loading photosensitizer chlorin e6 in SMONs-HA-Cy5.5.The resulting nanoplatform exhibits considerably higher therapeutic efficacy on tumors compared to the stiff ones.

近视青少年配戴角膜塑形镜前后脉络膜生物参数的变化

目的:应用光学相干断层扫描血管成像(OCTA)检测近视青少年配戴角膜塑形镜前后脉络膜生物参数的变化。方法:系列病例研究。连续纳入2020年7月至2022年10月在上海爱尔眼科医院视光门诊就诊的低中度近视青少年99例(99眼)。根据选择的矫正方式不同分为2组:对照组47例(47眼),配戴单焦点框架眼镜;角膜塑形镜组52例(52眼),配戴角膜塑形镜。所有患者于戴镜前、戴镜后3个月均进行眼轴长度(AL)、黄斑区OCTA的检测,通过OCTA检测获取黄斑区脉络膜毛细血管密度及中心凹下脉络膜厚度的数据。组间数据比较采用t检验,各参数相关性分析采用Spearman相关分析。结果:对照组组内戴镜前后脉络膜厚度、毛细血管密度差异均无统计学意义(均P>0.05);角膜塑形镜组组内戴镜前后脉络膜厚度、毛细血管密度差异均有统计学意义(t=-5.87,P<0.001;t=-5.15,P<0.001)。2组间戴镜前后脉络膜厚度变化量、脉络膜毛细血管密度变化量差异均有统计学意义(t=-5.79,P<0.001;t=-3.96,P<0.001)。对照组、角膜塑形镜组组内戴镜前后的AL差异均有统计学意义(t=-13.41,P<0.001;t=-3.70,P<0.001),但组间比较时角膜塑形镜组AL增幅小于对照组(t=2.46,P=0.016)。角膜塑形镜组戴镜前后AL增幅与脉络膜厚度变化量呈负相关(r=-0.54,P<0.001),与脉络膜毛细血管密度变化量无相关性(r=-0.12,P=0.380);对照组戴镜前后AL增幅与脉络膜厚度变化量、脉络膜毛细血管密度变化量均无相关性(均P>0.05)。结论:配戴角膜塑形镜的近视青少年AL增长延缓,黄斑区脉络膜毛细血管密度增加,中心凹下脉络膜厚度增加,且脉络膜厚度变化量与AL增幅有关,脉络膜增厚可能是控制近视进展的保护因素。

陆地生态系统中马陆的生态功能

马陆是陆地生态系统中物种多样性极高的大型土壤无脊椎动物类群。作为营腐生动物,马陆在陆地生态系统中具有不可替代的重要功能。通过大量取食及随后的肠道过程,马陆在很大程度上决定着陆地生态系统凋落物的破碎、转化和分解过程,从而驱动碳和关键养分元素的循环周转。然而,目前对马陆生态功能的研究还非常有限,远远落后于其他土壤动物类群(如蚯蚓等)。本文初步总结了马陆的生态功能:(1)通过破碎、取食凋落物来加速凋落物的分解。马陆偏好取食半分解的凋落物,其同化效率受到凋落物来源、温度和凋落物中微生物含量的影响。(2)主要通过取食和排泄等活动影响养分循环。但对于马陆如何影响土壤碳循环,存在两种不同的观点:一是马陆粪球的分解速率比凋落物更快,加速了碳的循环;二是马陆粪球更难分解,有助于碳的固存和稳定。马陆破碎凋落物后,凋落物释放氮素进入土壤。此外,马陆的活动也影响土壤磷的循环,提高土壤中有效磷的含量。(3)调控微生物特性,与蚯蚓也有互作关系。通过以上三个方面的总结,展望了未来马陆的主要研究方向,以期引起更多思考和研究。

海生杆菌属的基因组测序数据分析

海生杆菌属首次于1997年鉴定,迄今包括18个物种,其中10个已完成全基因组序列测定。文中总结了海生杆菌属的菌种特征,并从碳源利用、聚羟基脂肪酸酯代谢和芳香族化合物降解三个方面对基因组测序数据进行了分析。研究发现,海生杆菌属具有完整的糖酵解途径和三羧酸循环,缺乏木糖利用基因。所有海生杆菌属菌种均含有Ⅰ型和Ⅲ型聚羟基脂肪酸酯合成酶的编码基因,表明该菌属可能具有普遍的聚羟基脂肪酸酯合成能力。海生杆菌属含有芳香族化合物的降解途径,苯、苯酚和苯甲酸可由不同的酶催化生成邻苯二酚,再由邻位断裂途径降解为3-酮己二酸,邻苯二酚也可由间位断裂途径降解为丙酮酸和乙酰辅酶A。基因组测序数据分析加深了对海生杆菌属代谢特征的认识,提示该菌属在聚羟基脂肪酸酯合成和海洋芳香族污染物治理方面有一定的应用前景。

Emerging roles of circular RNAs in stem cells

Circular RNAs (circRNAs) are a novel class of noncoding RNAs that widely exist in eukaryotes. As a new focus in the field of molecular regulation, circRNAs have attracted much attention in recent years. Previous studies have confirmed that circRNAs are associated with many physiological and pathological processes. CircRNAs also participate in the regulation of stem cells. Stem cells have the properties of self-renewal and differentiation, which make stem cell therapy popular. CircRNAs may serve as new targets in stem cell therapy due to their regulation in stem cells. However, the underlying relationships between circRNAs and stem cells are still being explored. In this review, we briefly summarize the effects of circRNAs on stem cells, in the context of biological activities, aging and apoptosis, and aberrant changes. Moreover, we also examine the biological roles of stem cell-derived exosomal circRNAs. We believe our review will provide insights into the effects of circRNAs on stem cells.

GREEN AGRICULTURE AND BLUE WATER IN CHINA:REINTEGRATING CROP AND LIVESTOCK PRODUCTION FOR CLEAN WATER

Crop and livestock production are essential to maintain food security.In China,crop and livestock production were integrated in the past.Today,small backyard systems are still integrated but the larger livestock farms are landless and largely geographically separated from crop production systems.As a result,there is less recycling of animal manures and there are lower nutrient use efficiencies in the Chinese food production systems.This,in turn,results in considerable losses of nutrients,causing water pollution and harmful algal blooms in Chinese lakes,rivers and seas.To turn the tide,there is a need for agricultural“green”development for food production through reintegrating crop and livestock production.An additional wish is to turn the Chinese water systems“blue”to secure clean water for current and future generations.In this paper,current knowledge is summarized to identify promising interventions for reintegrating crop and livestock production toward clean water.Technical,social,economic,policy and environmental interventions are addressed and examples are given.The paper highlights recommended next steps to achieve“green”agriculture and“blue”water in China.

Wnt4 increases the thickness of the epidermis in burn wounds by activating canonical Wnt signalling and decreasing the cell junctions between epidermal cells

Background:Burn wound healing is a complex process and the role of Wnt ligands varies in this process.Whether and how Wnt4 functions in burn wound healing is not well understood.In this study,we aim to reveal the effects and potential mechanisms of Wnt4 in burn wound healing.Methods:First,the expression of Wnt4 during burn wound healing was determined by immunoflu-orescence,Western blotting and qPCR.Then,Wnt4 was overexpressed in burn wounds.The healing rate and healing quality were analysed by gross photography and haematoxyline and eosin staining.Collagen secretion was observed by Masson staining.Vessel formation and fibroblast distribution were observed by immunostaining.Next,Wnt4 was knocked down in HaCaT cells.The migration of HaCaT cells was analysed by scratch healing and transwell assays.Next,the expression ofβ-catenin was detected by Western blotting and immunofluorescence.The binding of Frizzled2 and Wnt4 was detected by coimmunoprecipitation and immunofluorescence.Finally,the molecular changes induced by Wnt4 were analysed by RNA sequencing,immunofluorescence,Western blotting and qPCR in HaCaT cells and burn wound healing tissues.Results:The expression of Wnt4 was enhanced in burn wound skin.Overexpression of Wnt4 in burn wound skin increased the thickness of epidermis.Collagen secretion,vessel formation and fibroblast distribution were not significantly impacted by Wnt4 overexpression.When Wnt4 was knocked down in HaCaT cells,the ratio of proliferating cells decreased,the ratio of apoptotic cells increased and the ratio of the healing area in the scratch healing assay to the number of migrated cells in the transwell assay decreased.The nuclear translocation ofβ-catenin decreased in shRNA of Wnt4 mediated by lentivirus-treated HaCaT cells and increased in Wnt4-overexpressing epidermal cells.RNA-sequencing analysis revealed that cell junction-related signalling pathways were significantly impacted by Wnt4 knockdown.The expression of the cell junction proteins was decreased by the overexpression of Wnt4.Conclusions:Wnt4 promoted the migration of epidermal cells.Overexpression of Wnt4 increased the thickness of the burn wound.A potential mechanism for this effect is that Wnt4 binds with Frizzled2 and increases the nuclear translocation ofβ-catenin,thus activating the canonical Wnt signalling pathway and decreasing the cell junction between epidermal cells.

WATER POLLUTION AND AGRICULTURE:MULTI-POLLUTANT PERSPECTIVES

Agriculture is an important cause of multiple pollutants in water.With population growth and increasing food demand,more nutrients,plastics,pesticides,pathogens and antibiotics are expected to enter water systems in the 21st century.As a result,water science has been shifting from singlepollutant to multi-pollutant perspectives for large-scale water quality assessments.This perspective paper summarizes and discusses four main highlights related to water pollution and agriculture from the multi-pollutant perspective.These highlights reveal the spatial and temporal distribution and main sources of multiple pollutants in waters.Based on the highlights,a scientific agenda is proposed to prioritize solutions for sustainable agriculture(UN Sustainable Development Goal 2)and clean water(UN Sustainable Development Goals 6 and 14).This agenda points out that when formulating solutions for water pollution,it is essential to take into account multiple pollutants and their interactions beyond biogeochemistry.

KCNMA1 promotes obesity-related hypertension:Integrated analysis based on genome-wide association studies

Obesity is caused by an excessive accumulation of fat,which poses a risk to human health.In China,the prevalence rates of overweight and obesity in adults were estimated to be 30.1%and 11.9%,respectively,ranking the first in the world.Obesity is a major risk factor for hypertension.