电化学合成耦合可再生能源制氢:机遇与挑战

利用可再生能源实现物质和能量的转化,是发展节能减排技术、实现双碳目标的重要手段.有机电合成是一种温和、清洁、高效的物质合成方法,可以有效解决传统化工过程的高能耗和高污染问题.将电解水制氢与有机电合成耦合,利用水分解产生的活性氧/氢直接氧化/还原有机物,不仅有助于降低能耗,还可以生产高附加值有机化工产品,是提高电能利用效率、降低生产成本的有效方案.然而,尽管这种方法具有诸多优势,其工业化应用仍面临一系列难题.本文回顾了电化学合成的发展历史,探讨了氢能时代为电化学合成带来的发展机遇.同时,分析了将电化学合成与电解水耦合所面临的挑战以及未来发展方向.首先,应当慎重选择与电解水制氢耦合的阳极反应体系,其氧化产物不但要具有比反应物更高的经济价值,而且要有较大的市场需求量,以匹配制氢规模.其次,虽然在热力学上有机物氧化比析氧更容易发生,但在动力学及传质方面,有机物氧化可能存在劣势,因此必须开发适用于工业制氢电流密度(500‒2000 mA cm^(‒2))的有机物氧化电极材料.第三,阳极有机产物选择性不仅影响反应物的利用率,而且决定后续分离纯化成本,需要通过调控活性氢/氧及有机物表面的竞争吸附等手段,提高阳极目标产物选择性及法拉第效率.第四,隔膜是分离两极反应物料、防止副反应发生的重要部件.然而,现有的阴、氧离子交换膜的耐有机物腐蚀性能差,需要开发适用于电解耦合体系的、具有高离子传导能力且性能稳定的新型隔膜材料.最后,当有机物氧化与电解水耦合后,产物的分离复杂程度增加,需要将精馏、萃取、膜分离等手段与电化学反应相结合,以提升电解过程效率.综上,本文讨论了电化学合成耦合可再生能源制氢的若干技术难题,为未来电合成与氢能技术共同发展提供新思路.

遗传修饰技术在绵羊分子设计育种中的应用

利用遗传修饰技术可以使动物在遗传水平发生改变,实现在个体内表达外源基因或对其内源基因的功能造成影响。在动物育种中,可以利用遗传修饰技术在分子水平进行设计并实现品种的快速改良。从传统的遗传修饰技术、病毒载体、精子载体等介导的遗传修饰技术到新型人工核酸酶介导的基因编辑技术,尤其是CRISPR/Cas9为代表的人工核酸酶的运用使得基因编辑动物的制备变得更加高效快捷,并迅速在多个物种中得到应用。这些方法也已经拓展到了绵羊(Ovis aries)遗传育种领域。利用遗传修饰技术在绵羊中进行分子育种比传统的育种方式具有更大的优势,可以使用多种策略直接对性状进行快速改良,并且可以加快育种进程。本文详细介绍了遗传修饰技术在绵羊中的研究历程,探讨了通过遗传修饰技术进行绵羊分子设计育种的可能性,并提出以上技术和方法在绵羊育种中面临的问题和挑战。

Recent developments in the use of single-atom catalysts for water splitting

Electrochemical water splitting is regarded as the most promising approach to produce hydrogen.However,the sluggish electrochemical reactions occurring at the anode and cathode,namely,the oxygen evolution reaction(OER)and the hydrogen evolution reaction(HER),respectively,consume a tremendous amount of energy,seriously hampering its wide application.Recently,single-atom catalysts(SACs)have been proposed to effectively enhance the kinetics of these two reactions.In this minireview,we focus on the recent progress in SACs for OER and HER applications.Three classes of SACs have been reviewed,i.e.,alloy-based SACs,carbon-based SACs and SACs supported on other compounds.Different factors affecting the activities of SACs are also highlighted,including the inherent element property,the coordination environment,the geometric structure and the loading amount of metal atoms.Finally,we summarize the current problems and directions for future development in SACs.

Hierarchically porous nitrogen-doped carbon as cathode for lithium–sulfur batteries

Porous nitrogen-doped carbon is an especially promising material energy storage due to its excellentconductivity, stable physicochemical properties, easy processability, controllable porosity and low price.Herein, we reported a novel well-designed hierarchically porous nitrogen-doped carbon （HPNC） via acombination of salt template （ZnC12） and hard template （SiO2） as sulfur host for lithium-sulfur batter-ies. The low-melting ZnC12 is boiled off and leaves behind micropores and small size mesopores duringpyrolysis process, while the silica spheres are removed by acid leaching to generate interconnected 3Dnetwork of macropores. The HPNC-S electrode exhibits an initial specific capacity of 1355 mAh g^-l at 0.IC （IC= 1675 mAh g^-1 ）, a high-rate capability of 623 mAh g-l at 2 C, and a small decay of 0.13% per cycleover 300 cycles at 0.2 C. This excellent rate capability and remarkable long-term cyclability of the HPNC-Selectrode are attributed to its hierarchical porous structures for confining the soluble lithium polysulfideas well as the nitrogen doping for high absorbability of lithium polysulfide.

New players in the regulation of ecdysone biosynthesis

Insect ecdysone steroid hormone regulates major developmental transitions, such as molting and metamorphosis. The production of ecdysone correlates well with the timing of these transitions. Finding out how the ecdysone biosynthesis is regulated is crucial to fully understand these sophisticated developmental switches. Here we summarized recent findings in the regulation of ecdysone biosynthesis from the aspects of cell signaling, key biosynthetic enzymes and substrate cholesterol trafficking.

Design method for an acoustic cloak in flows by topology optimization

In this paper,a design method for an acoustic cloak in the presence of background mean flows is proposed by using topology optimization,which enables the associated fabrication of the cloaking design.The density-based topology optimization method is used to allocate the designated materials,thus providing the structure of the cloak.The optimization problem is efficiently solved with the gradient-based globally convergent method of moving asymptotes,which utilizes the derivative information from the finite element simulation studies of the linearized acoustic potential equation.This paper introduces the whole design method first then numerically demonstrates the corresponding performance,which shall constitute the main contribution of the present work.

Overcoming chemoresistance in non-angiogenic colorectal cancer by metformin via inhibiting endothelial apoptosis and vascular immaturity

The development of chemoresistance which results in a poor prognosis often renders current treatments for colorectal cancer(CRC).In this study,we identified reduced microvessel density(MVD)and vascular immaturity resulting from endothelial apoptosis as therapeutic targets for overcoming chemoresistance.We focused on the effect of metformin on MVD,vascular maturity,and endothelial apoptosis of CRCs with a non-angiogenic phenotype,and further investigated its effect in overcoming chemoresistance.In situ transplanted cancer models were established to compare MVD,endothelial apoptosis and vascular maturity,and function in tumors from metformin-and vehicle-treated mice.An in vitro co-culture system was used to observe the effects of metformin on tumor cell-induced endothelial apoptosis.Transcriptome sequencing was performed for genetic screening.Non-angiogenic CRC developed independently of angiogenesis and was characterized by vascular leakage,immaturity,reduced MVD,and non-hypoxia.This phenomenon had also been observed in human CRC.Furthermore,non-angiogenic CRCs showed a worse response to chemotherapeutic drugs in vivo than in vitro.By suppressing endothelial apoptosis,metformin sensitized non-angiogenic CRCs to chemo-drugs via elevation of MVD and improvement of vascular maturity.Further results showed that endothelial apoptosis was induced by tumor cells via activation of caspase signaling,which was abrogated by metformin administration.These findings provide pre-clinical evidence for the involvement of endothelial apoptosis and subsequent vascular immaturity in the chemoresistance of non-angiogenic CRC.By suppressing endothelial apoptosis,metformin restores vascular maturity and function and sensitizes CRC to chemotherapeutic drugs via a vascular mechanism.

Hierarchical coral-like FeNi(OH)_x/Ni via mild corrosion of nickel as an integrated electrode for efficient overall water splitting

Efficient,stable,and noble‐metal‐free electrocatalysts for both the oxygen evolution reaction and the hydrogen evolution reaction are highly imperative for the realization of low‐cost commercial water‐splitting electrolyzers.Herein,a cost‐effective and ecofriendly strategy is reported to fabricate coral‐like FeNi(OH)x/Ni as a bifunctional electrocatalyst for overall water splitting in alkaline media.With the assistance of mild corrosion of Ni by Fe(NO3)3,in situ generated FeNi(OH)x nanosheets are intimately attached on metallic coral‐like Ni.Integration of these nanosheets with the electrodeposited coral‐like Ni skeleton and the supermacroporous Ni foam substrate forms a binder‐free hierarchical electrode,which is beneficial for exposing catalytic active sites,accelerating mass transport,and facilitating the release of gaseous species.In 1.0 mol L^-1 KOH solution,a symmetric electrolyzer constructed with FeNi(OH)x/Ni as both the anode and the cathode exhibits an excellent activity with an applied potential difference of 1.52 V at 10 mA cm^-2,which is superior to that of an asymmetric electrolyzer constructed with the state‐of‐the‐art RuO2‐PtC couple(applied potential difference of 1.55 V at 10 mA cm^-2).This work contributes a facile and reliable strategy for manufacturing affordable,practical,and promising water‐splitting devices.

Improved hydrogen oxidation reaction under alkaline conditions by Au–Pt alloy nanoparticles

This work demonstrates the outstanding performance of alloyed Au1 Pt1 nanoparticles on hydrogen oxidation reaction(HOR)in alkaline solution.Due to the weakened hydrogen binding energy caused by uniform incorporation of Au,the alloyed Au1Pt1/C nanoparticles exhibit superior HOR activity than commercial PtRu/C.On the contrary,the catalytic performance of the phase-segregated Au2Pt1/C and Au1Pt1/C bimetallic nanoparticles in HOR is significantly worse.Moreover,Au1Pt1/C shows a remarkable durability with activity dropping only 4% after 3000 CV cycles,while performance attenuation of commercial PtRu/C is high up to 15% under the same condition.Our results indicate that the alloyed Au1Pt1/C is a promising candidate to substitute commercial PtRu/C for hydrogen oxidation reaction in alkaline electrolyte.

High-order schemes for predicting computational aeroacoustic propagation with adaptive mesh refinement

High-order schemes based on block-structured adaptive mesh refinement method are prepared to solve computational aeroacoustic （CAA） problems with an aim at improving computational efficiency. A number of numerical issues associated with high-order schemes on an adaptively refined mesh, such as stability and accuracy are addressed. Several CAA benchmark problems are used to demonstrate the feasibility and efficiency of the approach.

Stay in touch with the endoplasmic reticulum

The endoplasmic reticulum(ER),which is composed of a continuous network of tubules and sheets,forms the most widely distributed membrane system in eukaryotic cells.As a result,it engages a variety of organelles by establishing membrane contact sites(MCSs).These contacts regulate organelle positioning and remodeling,including fusion and fission,facilitate precise lipid exchange,and couple vital signaling events.Here,we systematically review recent advances and converging themes on ER-involved organellar contact.The molecular basis,cellular influence,and potential physiological functions for ER/nuclear envelope contacts with mitochondria,Golgi,endosomes,lysosomes,lipid droplets,autophagosomes,and plasma membrane are summarized.

Research Progress on Bio‑inspired Flapping‑Wing Rotor Micro Aerial Vehicle Development

Flapping-wing rotor(FWR)is an innovative bio-inspired micro aerial vehicle capable of vertical take-off and landing.This unique design combines active flapping motion and passive wing rotation around a vertical central shaft to enhance aerodynamic performance.The research on FWR,though relatively new,has contributed to 6%of core journal publications in the micro aerial vehicle field over the past two decades.This paper presents the first comprehensive review of FWR,analysing the current state of the art,key advances,challenges,and future research directions.The review highlights FWR’s distinctive kinematics and aerodynamic superiority compared to traditional flapping wings,fixed wings,and rotary wings,discussing recent breakthroughs in efficient,passive wing pitching and asymmetric stroke amplitude for lift enhancement.Recent experiments and remote-controlled take-off and hovering tests of single and dual-motor FWR models have showcased their effectiveness.The review compares FWR flight performance with well-developed insect-like flapping-wing micro aerial vehicles as the technology readiness level progresses from laboratory to outdoor flight testing,advancing from the initial flight of a 2.6 g prototype to the current free flight of a 60-gram model.The review also presents ongoing research in bionic flexible wing structures,flight stability and control,and transitioning between hovering and cruise flight modes for an FWR,setting the stage for potential applications.

Variants within KIF5B are associated with weight loss through mitochondrial transport alteration in sheep

Sheep(Ovis aries)is a key source of meat for humans,and their weight loss significantly impacts meat production.Although a few causative genes related to weight loss have been identified,the inheritance mechanisms and genetic pathways involved remain to be further elucidated.Artificial selection can effectively fix substantial mutations in these genes,enhancing meat production in sheep.Kinesin family member 5B(KIF5B)is a member of the kinesin-1protein family,which is made up of two kinesin heavy chains(KHCs)and two kinesin light chains(KLCs).Each kinesin motor head features an ATP pocket and a microtubule-binding domain,enabling it to function as a molecular motor(Hirokawa et al.,2009).

Reducing Energy Costs during Hydrogen Production from Water Electrolysis by Coupling Small Molecule Oxidation: From Molecular Catalysis to Industrial Exploration

Hydrogen energy has garnered significant attention in recent years as a solution to address the global energy crisis and environmental pollution.While water electrolysis stands out as the most promising method to produce green hydrogen,the sluggish reaction kinetics of the oxygen evolution reaction(OER)on the anode increases the cost of hydrogen production.One potential solution to this challenge is replace OER with the thermodynamically more favorable oxidation of small molecules,which can efficiently reduce the energy cost while simultaneously yielding high-value chemicals.Up to now,various organic oxidation reactions have been reported to couple with hydrogen evolution,including alcohol oxidation,biomass platform molecule upgrading,and sacrificial reagents oxidation associated with wastewater treatments.This review concentrates on the recent advancements in the mechanism,catalyst,reactor,and process in this field,with a discussion on its prospects for commercialization.

在线教育服务创新:服务绩效制约因素关联性诊断视角

哪些因素制约了在线教育的成效?过去二十年,学术界一直致力于对该命题的探索并取得了丰硕的研究成果。然而,这些因素之间存在的系统关联性却一直未受到关注。本文遵循服务主导逻辑视角,引入服务营销领域中的服务、服务绩效与服务创新等概念,运用系统工程解释结构模型(ISM)建模,寻找当前在线教育服务绩效制约因素的整体性特征。研究有两项发现:一是识别出目前影响在线教育服务绩效的服务供应链环节与服务营销组合要素,二是区分制约在线教育服务绩效的表层直接因素、中层间接因素与深层根源因素,提出服务创新路径建议,为提升在线教育服务绩效提供适用性指导。

Regulation of glucose and lipid metabolism in health and disease

Glucose and fatty acids are the major sources of energy for human body. Cholesterol, the most abundant sterol in mammals, is a key component of cell membranes although it does not generate ATP. The metabolisms of glucose, fatty acids and cholesterol are often intertwined and regulated. For example, glucose can be converted to fatty acids and cholesterol through de novo lipid biosynthesis pathways. Excessive lipids are secreted in lipoproteins or stored in lipid droplets. The metabolites of glucose and lipids are dynamically transported intercellularly and intracellularly, and then converted to other molecules in specific compartments. The disorders of glucose and lipid metabolism result in severe diseases including cardiovascular disease, diabetes and fatty liver. This review summarizes the major metabolic aspects of glucose and lipid, and their regulations in the context of physiology and diseases.

Comparison of laparoscopic selective colectomy based on barium-strip examination and subtotal colectomy for adult slow-transit constipation

Background:Surgical management of adult slow-transit constipation(ASTC)can be effective for patients with intractable symptoms.This study aimed to evaluate whether barium-strip examination and selective colectomy improved post-operative outcomes in ASTC patients in comparison with subtotal colectomy.Methods:A retrospective cohort study of 53 cases with refractory ASTC was conducted between June 2008 and June 2014.Patients were evaluated by the barium-strip technique,colonoscopy,defecography and anorectal manometry.Patients in the standard group underwent laparoscopic subtotal colectomy and patients in the laparoscopic selective colectomy(LSC)group underwent LSC at the precise location identified by barium strip.Spontaneous bowel movements,the Wexner Constipation Scale and the Gastrointestinal Quality of Life Index(GIQLI)were assessed post-operatively at 3,6,12 and 24 months.Results:A total of 49 patients were included in the analysis.The median follow-up was 37 months(range,26–60 months).The mean post-operative hospital stay was 12 days and similar between groups(P=0.071).The length of colon resection,operative time and intra-operative blood loss were reduced in the LSC group(all P<0.05).No major complications occurred.A similar number of patients(24 in the standard group and 25 in the LSC group)exhibited hypoganglionosis or aganglionosis in the colon-wall muscle layer(P=0.986).Although there were no significant differences in post-operative spontaneous bowel movements and the Wexner Constipation Scale between the two groups,the mean GIQLI of the LSC group was significantly higher at 3,6 and 24 months post-operatively(all P<0.05).Conclusions:LSC based on barium-strip examination is an appropriate modality for treating ASTC.

Hepatic CDP-diacylglycerol synthase 2 deficiency causes mitochondrial dysfunction and promotes rapid progression of NASH and fibrosis

Nonalcoholic fatty liver disease(NAFLD)encompasses a spectrum of pathologies,ranging from steatosis to nonalcoholic steatohepatitis(NASH).The factors promoting the progression of steatosis to NASH are still unclear.Recent studies suggest that mitochondrial lipid composition is critical in NASH develop-ment.Here,we showed that CDP-DAG synthase 2(Cds2)was downregulated in genetic or diet-induced NAFLD mouse models.Liver-specific deficiency of Cds2 provoked hepatic steatosis,inflammation and fibrosis in five-week-old mice.CDS2 is enriched in mitochondria-associated membranes(MAMs),and hepatic Cds2 deficiency impaired mitochondrial function and decreased mitochondrial PE levels.Overexpression of phosphatidylserine decarboxylase(PISD)alleviated the NASH-like phenotype in Cds2^(f/f);AlbCre mice and abnormal mitochondrial morphology and function caused by CDS2 deficiency in hepatocytes.Additionally,dietary supplementation with an agonist of peroxisome proliferator-activated receptor alpha(PPARa)attenuated mitochondrial defects and ameliorated the NASH-like phe-notype in Cds2^(f/f);AlbCre mice.Finally,Cds2 overexpression protected against high-fat diet-induced hepatic steatosis and obesity.Thus,Cds2 modulates mitochondrial function and NASH development.

A Lipid Droplet-Associated GFP Reporter-Based Screen Identifies New Fat Storage Regulators in C.elegans

Fat storage disorders including obesity are pandemic human health problems. As a genetically amenable model organism, Caeno- rhabditis elegans has often been used to explore the molecular mechanisms of fat storage regulation. Dye staining of fixed animals and stimulated Raman scattering （SRS） microscopy methods have been used successfully to study fat storage, but a genetic screening system that takes full advantage of C. elegans transparency to perform live imaging of fluorescent protein reporters has not yet been reported. Here, we investigated the tissue-specific expression of the GFP fusion of Perilipin 1 （PLIN1）, a Drosophila lipid droplet-associated protein, in C. elegans. Our results indicate that PLINI：：GFP labels lipid droplets and can be used as a fat storage indicator in live worms. Through an RNAi screen, we further identified several previously uncharacterized new fat storage regulators.

Lipid storage regulator CdsA is essential for Drosophila metamorphosis

Steroid hormones are one of the major bioactive lipid species that regulate a large number of physiological processes including developmental transitions, growth, metabolism, inflammation, immune response and reproduction in animals. In insects, steroid hormones ecdysone and 20-hydroxyecdysone (20E) trigger the major transitional events, molting and metamorphosis (Thummel, 1996). In Drosophila, ecdysone synthesis primarily occurs in the prothoracic gland, an endocrine gland expressing a large number of ecdysone biosynthetic enzymes required for a series of hydroxylation and oxidation steps.