Electrocatalysts with atomic-level site for nitrate reduction to ammonia

Ammonia(NH_(3))is an important raw material for modern agriculture and industry,being widely demanded to sustain the sustainable development of modern society.Currently,the industrial production methods of NH_(3),such as the traditional Haber-Bosch process,have drawbacks including high energy consumption and significant carbon dioxide emissions.In recent years,the electrocatalytic nitrate reduction reaction(NO_(3)RR)powered by intermittent renewable energy sources has gradually become a multidisciplinary research hotspot,as it allows for the efficient synthesis of NH_(3)under mild conditions.In this review,we focus on the research of electrocatalysts with atomic-level site,which have attracted attention due to their extremely high atomic utilization efficiency and unique structural characteristics in the field of NO_(3)RR.Firstly,we introduce the mechanism of nitrate reduction for ammonia synthesis and discuss the in-situ characterization techniques related to the mechanism study.Secondly,we review the progress of the electrocatalysts with atomic-level site for nitrate reduction and explore the structure-activity relationship to guide the rational design of efficient catalysts.Lastly,the conclusions of this review and the challenges and prospective of this promising field are presented.

六味地黄汤对血液透析患者肝肾阴虚型血小板减少症的疗效观察

目的观察六味地黄汤对血液透析患者肝肾阴虚型血小板减少症(HIT)的治疗效果。方法84例血液透析肝肾阴虚型HIT患者随机分为观察组与对照组各42例。对照组给予常规西医治疗,观察组在对照组基础上加用六味地黄汤治疗。两组疗程均为1个月。比较两组治疗前后肝肾阴虚证候积分变化及中医证候疗效;比较两组治疗前后血小板计数(Plt)、P-选择素水平、HIT抗体阳性率变化,以及两组Plt回升时间、临床疗效和不良反应发生率。结果治疗1个月后,两组肝肾阴虚证候积分均较前降低(P<0.05),且观察组低于对照组(P<0.05);观察组中医证候总有效率(97.62%)高于对照组(P<0.05)。治疗14 d后,两组Plt均较前升高,P-选择素水平、HIT抗体阳性率则较前降低(P<0.05),且观察组Plt高于对照组,P-选择素水平、HIT抗体阳性率低于对照组(P<0.05)。观察组Plt回升时间短于对照组(P<0.05),临床总有效率(95.24%)高于对照组(P<0.05);两组治疗期间不良反应发生率差异无统计学意义(P>0.05)。结论常规西医联合六味地黄汤治疗血液透析患者的肝肾阴虚型HIT,可提高临床疗效,减轻患者临床症状,提高Plt,缩短Plt回升时间,降低P-选择素水平和HIT抗体阳性率,且安全性良好,值得临床推广。

miR-362靶向ZNF644基因调控猪未成熟支持细胞的增殖和凋亡

睾丸组织中未成熟支持细胞的增殖能力决定成熟支持细胞的数量,进而制约成年雄性动物的精子生成能力。研究表明microRNA(miRNA)参与调控猪未成熟支持细胞的增殖和凋亡,但大部分鉴定出的miRNA功能仍不明确。本文基于前期RNA-seq数据筛选结果,研究了miR-362对猪未成熟支持细胞增殖和凋亡的调控作用。首先利用生物信息学方法预测miR-362的靶基因,通过qRT-PCR技术检测miR-362和ZNF644基因在不同发育阶段的猪睾丸组织中的表达水平以及在猪未成熟支持细胞中过表达或抑制表达miR-362后ZNF644基因的表达水平,采用双荧光素酶报告基因系统验证miR-362与ZNF644基因之间的靶向关系。结果显示,miR-362与ZNF644基因3′UTR具有一个潜在的结合位点,miR-362和ZNF644基因在猪睾丸组织中的mRNA表达水平显著负相关(r=-0.723,P<0.01),miR-362和psi CHECK2-ZNF644-WT 3′UTR共转染组的双荧光活性显著降低,且miR-362显著调节ZNF644基因的表达水平,表明miR-362靶向ZNF644基因并抑制其表达水平。为进一步检测过表达miR-362或抑制表达ZNF644基因对猪未成熟支持细胞增殖和凋亡的影响,通过流式细胞术检测细胞周期,CCK8和EdU试剂盒检测细胞增殖情况,Annexin V-FITC/PI方法和qRT-PCR技术检测细胞凋亡情况及凋亡相关基因的表达水平。结果表明,过表达miR-362后,猪未成熟支持细胞周期被阻滞在G_1期,抑制表达ZNF644基因后,猪未成熟支持细胞被阻滞在G2期,细胞增殖能力显著减弱,细胞凋亡率显著提高,细胞凋亡相关基因呈促进凋亡的差异表达。本研究结果证实miR-362靶向ZNF644基因抑制猪未成熟支持细胞的增殖而促进其凋亡,为深入研究miR-362在猪精子生成过程中的生物学功能提供了理论基础。

Action Mechanism of Antibacterial Hydrolysate from Ruditapes philippinarum

[Objectives] The antibacterial mechanism of protein hydrolysate from Ruditapes philippinarum（ named RPPH） was studied in this article. [Methods]The integrity of bacteria＇s wall and membrane was determined by some traditional ways. [Results]The growth of Staphylococcus aureus and Bacillus subtilis were inhibited by RPPH in the logarithmic phase. The activity of alkaline phosphatase could be detected in the culture solution. The results showed that the protein content and the conductivity of two kinds of bacteria increased with the extension of incubation time. The results of scanning electron microscope revealed that it emerged the phenomenon of agglomeration with the extension of response time in the culture solution of S. aureus,and the cell shape became irregular,a large number of cells stuck together,afterwards intracellular material was released from bacteria,and the boundaries among cells completely disappeared. The cell surface of B. subtilis became rough,the cells began to adhere,intercellular boundaries became blurred,subsequently cells broke,and then intracellular material leaked out after treating for 9 h. The form of B. subtilis could be roughly identified from the remnants of the bacterial debris,and most of the bacteria had been completely cracked and died. Transmission electron microscope results showed that the surface of S. aureus became rough,with uneven distribution of cytoplasm,and darker substances appeared in the middle,followed by leakage of large numbers of intracellular material. Massive cells became dead when treating for 9 h. B. subtilis cells began to shrink,and cytoplasm was distributed unevenly. The significant phenomenon of plasmolysis and rupture of cell wall could be observed. Afterwards,intracellular material spilled out,only the residual and ambiguity nucleoplasm area could be seen,and cells were killed. [Conclusions] Therefore,it was speculated that the RPPH could destroy cell wall and membrane of the two kinds of bacteria,change the permeability of cells membrane,result in the leakage of intracellular substances and enter within the bacterial cells to affect their normal physiological metabolism which led to death.

Expenditure and financial burden for the diagnosis and treatment of colorectal cancer in China:a hospital.based,multicenter,cross-sectional survey

Background: The increasing prevalence of colorectal cancer(CRC) in China and the paucity of information about relevant expenditure highlight the necessity of better understanding the financial burden and effect of CRC diagnosis and treatment. We performed a survey to quantify the direct medical and non-medical expenditure as well as the resulting financial burden of CRC patients in China.Methods: We conducted a multicenter, cross-sectional survey in 37 tertiary hospitals in 13 provinces across China between 2012 and 2014. Each enrolled patient was interviewed using a structured questionnaire. All expenditure data were inflated to the 2014 Chinese Yuan(CNY; 1 CNY = 0.163 USD). We quantified the overall expenditure and financial burden and by subgroup(hospital type, age at diagnosis, sex, education, occupation, insurance type, household income, clinical stage, pathologic type, and therapeutic regimen). We then performed generalized linear modeling to determine the factors associated with overall expenditure.Results: A total of 2356 patients with a mean age of 57.4 years were included, 57.1 % of whom were men; 13.9% of patients had stage I cancer; and the average previous-year household income was 54,525 CNY.The overall average direct expenditure per patient was estimated to be 67,408 CNY, and the expenditures for stage Ⅰ, Ⅱ, Ⅲ, and Ⅳ disease were 56,099 CNY, 59,952 CNY, 67,292 CNY, and 82,729 CNY, respectively. Non-medical expenditure accounted for 8.3%of the overall expenditure. The 1-year out-of-pocket expenditure of a newly diagnosed patient was 32,649 CNY, which accounted for 59.9% of their previous-year household income and caused 75.0% of families to suffer an unmanageable financial burden. Univariate analysis showed that financial burden and overall expenditure differed in almost all subgroups(P < 0.05), except for sex. Multivariate analysis showed that patients who were treated in specialized hospitals and those who were diagnosed with adenocarcinoma or diagnosed at a later stage were likely to spend more,whereas those with a lower household income and those who underwent surgery spent less(all P < 0.05).Conclusions: For patients in China, direct expenditure for the diagnosis and treatment of CRC seemed catastrophic,and non-medical expenditure was non-ignorable. The financial burden varied among subgroups, especially among patients with different clinical stages of disease, which suggests that, in China, CRC screening might be cost-effective.

Medical expenditure for esophageal cancer in China:a 10-year multicenter retrospective survey(2002-2011)

Background: Esophageal cancer is associated with substantial disease burden in China, and data on the economic burden are fundamental for setting priorities in cancer interventions. The medical expenditure for the diagnosis and treatment of esophageal cancer in China has not been fully quantified. This study aimed to examine the medical expenditure of Chinese patients with esophageal cancer and the associated trends.Methods: From 2012 to 2014, a hospital-based multicenter retrospective survey was conducted in 37 hospitals in 13 provinces/municipalities across China as a part of the Cancer Screening Program of Urban China. For each esophageal cancer patient diagnosed between 2002 and 2011, clinical information and expense data were extracted by using structured questionnaires. All expense data were reported in Chinese Yuan(CNY; 1 CNY = 0.155 USD) based on the2011 value and inflated using the year-specific health care consumer price index for China.Results: A total of 14,967 esophageal cancer patients were included in the analysis. It was estimated that the overall average expenditure per patient was 38,666 CNY, and an average annual increase of 6.27% was observed from 2002(25,111 CNY) to 2011(46,124 CNY). The average expenditures were 34,460 CNY for stage Ⅰ,39,302 CNY for stage Ⅱ,40,353 CNY for stage Ⅲ, and 37,432 CNY for stage IV diseases(P < 0.01). The expenditure also differed by the therapy type, which was 38,492 CNY for surgery, 27,933 CNY for radiotherapy, and 27,805 CNY for chemotherapy(P < 0.05).Drugs contributed to 45.02% of the overall expenditure.Conclusions: These conservative estimates suggested that medical expenditures for esophageal cancer in China substantially increased in the last 10 years, treatment for early-stage esophageal cancer costs less than that for advanced cases, and spending on drugs continued to account for a considerable proportion of the overall expenditure.

Chemical and boron isotopic compositions of tourmaline in the Longtoushan hydrothermal gold deposit, Guangxi, China:implications for gold mineralization

The Longtoushan hydrothermal gold deposit is located in the southwestern region of the Dayaoshan Uplift.Tourmaline is widespread in the Longtoushan gold deposit and is mainly distributed in the rhyolite porphyry and associated cryptoexplosive breccia. The spatial distribution of tourmaline enrichment is similar to that of the gold orebody. Feldspar has been largely replaced by tourmaline in the rhyolite porphyry and cryptoexplosive breccia.Electron microprobe analysis revealed that tourmalines in the Longtoushan deposit belong mainly to the alkali group and partly to the X-vacant group; they mostly fell in the schorl-dravite series field. Two distinct sets of dominant substitutions were observed: MgFe_(-1) and Al□(NaR2+)-1,where R = Fe, Mg. In addition, minor substitutions include(CaMg)(NaAl)_(-1) and FeAl_(-1). The calculated d11 B value for the mineralizing fluids ranged from-12.8 to-9.7%,which is typical of S-type granites, and boron-enriched fluids predominantly derived from rhyolitic melt. Part of the tourmaline from the rhyolite porphyry crystallized during the magmatic-hydrothermal stage, whereas most tourmalines from the deposit formed in the post-magmatic hydrothermal stage. The tourmalines were deposited from a relatively reduced and acidic fluid system, and the gold predominantly precipitated during the post-magmatic hydrothermal stage in the Longtoushan deposit.

Application of Brain-Computer-Interface in Awareness Detection Using Machine Learning Methods

The awareness detection in patients with disorders of consciousness currently relies on behavioral observations and CRS-R tests,however,the misdiagnosis rates have been relatively high.In this study,we applied brain-computer interface(BCI)to awareness detection with a passive auditory stimulation paradigm.12 subjects with normal hearing were invited to collect electroencephalogram(EEG)based on a BCI communication system,in which EEG signals are transmitted wirelessly.After necessary preprocessing,RBF-SVM and EEGNet were used for algorithm realization and analysis.For a single subject,RBF-SVM can distinguish his(her)name stimuli awareness with classification accuracies ranging from 60-95%.EEGNet was used to learn all subjects'data and improved accuracy to 78.04%for characteristics finding and model generalization.Moreover,we completed the supplementary analysis work from the time domain and time-frequency domain.This study applied BCI communication to human awareness detection,proposed a passive auditory paradigm,and proved the effectiveness,which could be an inspiration for brain,mental or physical diseases diagnosis and detection.

Pt nanodendrites with a PtIr alloy surface structure exhibit excellent stability toward acidic hydrogen evolution reaction

The development of effective and stable electrocatalysts for the hydrogen evolution reaction(HER)in acidic electrolytes is a significant challenge.In this work,homogeneous Pt nanodendrites(Pt NDs)with a PtIr shell were successfully synthesized by a two-step wet chemical method.This open three-dimensional(3D)dendritic structure exhibited exceptional electrocatalytic characteristics,exposing as many active sites as feasible.Furthermore,by alloying Ir with Pt on the surface,catalytic activity was greatly enhanced while ensuring extremely high stability.Iridium surface-enriched platinum nanodendritic catalysts(Pt@PtIr NDs)outperformed the control samples and the commercial catalysts.In acidic HER test,Pt@PtIr NDs had a lower overpotential(22 mV)than Pt NDs(26 mV)and commercial Pt/C(31 mV)at 10 mA/cm^(2),and the activity of Pt@PtIr NDs remained consistent even after undergoing a continuous durability test for at least 168 h,which was much superior to the performance of commercial Pt/C(10 h)under identical test conditions.This study revealed that the application of 3D Pt dendritic metal alloys may offer a chance for the development of enhanced electrocatalysts in acidic HER.

Taphonomy and Paleoecology of Lycoptera: A Case Study from the Lower Jehol Group in Western Liaoning, Northeastern China

Taphonomy and paleoecology(biological behavior)of the Early Cretaceous fish fossils are poorly described.This study reports for the first time a detailed taphonomical and paleoecological study on Lycoptera in the Mesozoic strata of western Liaoning Province,NE China.The XRD analysis shows that gismondine is the dominant clay minerals that could have contributed to the preservation of Lycoptera fossils and microbial mat fragments in the fossil-bearing horizon.Gismondine may have formed under volcanism-related hydrothermal regime that was transformed from crystal and lithic fragments.Theμ-XRF imaging analysis shows a dominant chemical composition of Al,Si,P,S,Rh,K,Ca,Ti,C,Cr,Mn,Fe,Ni,among which P,Ca,C and S are enriched in the fish skeleton in comparison to the matrix.This suggests a dominant apatite composition for the fish skeleton.Hydrothermal influence did not smear off these organic signals probably because of protection of gismondine.The coexistance of C and S with Ni is assumed to represent recovered primary productivity following volcanic explosions and toxic gas emissions.The head of juvenile fish stays close to the body of adult fish.Pending further discoveries,such phenomenon is interpreted to suggest that adult fish actively protected juvenile fish in the presence of environmental pressures such as anoxia and deterioration of water quality induced by volcanism.Ocean acidification and hypoxia in association with volcanism created a harmful environment causing mass extinction of fish.The adult Lycoptera protected their juveniles by its body at the moment before death.Such biological behavior will be increasingly reported given the wide occurrence of Lycoptera in Mesozoic strata.

Plasmon-enhanced photocatalytic oxidative coupling of amines in the air using a delicate Ag nanowire@NH_(2)-UiO-66 core-shell nanostructures

MOF-based core-shell structures with high surface area, abundant active sites, and broad absorption bands are viable alternatives to traditional single-component photocatalysts. In this report, we describe the design and construction of delicate Ag nanowires@NH_(2)-UiO-66 with a core-shell structure for use as photocatalysts in imine synthesis under light. The optimized composites exhibited 80% imine production, which was higher than both MOF and Ag NWs. The significant improvement in photocatalytic activity under light may be attributed to the plasmonic effect of silver nanowires and their core-shell structure, which promotes the separation of electron-hole pairs. Moreover, the photocatalytic activity of the core-shell nanostructure may provide valuable insight into the design and construction of MOF-based composite photocatalysts for oxidative coupling of amines.

Residual levels and health risk assessment of trace metals in Chinese resident diet

Large-scale metal contamination across the food web is an intractable problem due to increasing pollutant emissions,atmospheric transport,and dry and wet deposition of elements.The present study focus on several trace metals that are rarely studied but have special toxicity,including tin(Sn),antimony(Sb),gold(Au),hafnium(Hf),palladium(Pd),platinum(Pt),ruthenium(Ru),tellurium(Te)and iridium(Ir).We investigated trace metals residues and distribution characteristics,and further evaluated the potential health risks from major daily food intakes in 33 cities in China.Sn,Sb,Ir,Hf,and Au were frequently detected in food samples with the concentrations ranged from ND(not detected)to 24.78μg/kg ww(wet weight).Eggs exhibited the highest residual level of all detected metals(13.70±14.70μg/kg ww in sum),while the lowest concentrations were observed in vegetables(0.53±0.17μg/kg ww in sum).Sn accounting for more than 50%of the total trace metals concentration in both terrestrial and aquatic animal origin foods.In terrestrial plant origin foods,Sn and Ir were the most abundant elements.Hf and Au were the most abundant elements in egg samples.In addition,Sb and Ir showed a clear trophic dilution effect in terrestrial environments,while in aquatic ecosystems,Sn,Hf,and Au exhibited obvious trophic amplification effects.The calculated average estimated daily intake(EDI)via food consumption in five regions of China was 0.09μg/(kg·day),implying the health risk of aforementioned elements was acceptable.

Tandem catalysis of Cu/Ni multi-sites promotes oxygen reduction reaction

The special electronic characteristics and high atom usage efficiency of metal-nitrogen-carbon(M-N-C)materials have made them extremely attractive for oxygen reduction reactions(ORRs).However,it is inevitable that hydrogen peroxide(H_(2)O_(2))will be formed via the two-electron pathway in ORRs.Herein,the Cu nanoparticles(NPs)have been encapsulated into Ni doped hollow mesoporous carbon spheres(Ni-HMCS)to reduce the generation of H_(2)O_(2)in ORR.Electrochemical tests confirm that the introduction of Cu NPs improves the ORR performance greatly.The obtained Cu/Ni-HMCS exhibits a half-wave potential of 0.82 V vs.reversible hydrogen electrode and a limited current density of 5.5 mA cm^(-2),which is comparable with the commercial Pt/C.Moreover,Cu/Ni-HMCS has been used in Zn-air battery,demonstrating a high power density of 161 mW cm^(-2)and a long-term recharge capability(50 h at 5 mA cm^(-2)).The theoretical calculation proposes a tandem catalysis pathway for Cu/Ni multi-sites catalysis,that is,H_(2)O_(2)released from the Ni-N_(4)and Cu-N_(4)sites migrates to the Cu(111)face,on which the captive H_(2)O_(2)is further reduced to H_(2)O.This work demonstrates an interesting tandem catalytic pathway of dual-metal multi-sites for ORR,which provides an insight into the development of effective fuel cell electrocatalysts.

Hydrogen-bonded organic framework core–shell composite for synergistic antimicrobial therapy

Hydrogen-bonded organic frameworks(HOFs)are crystalline porous materials with permanent voids formed via self-assembly of organic molecules through hydrogen bonding and intermolecular forces.Further combination of HOFs with functional material would broaden their application horizon but were less explored in existing literature.Herein,a highly porous and photosensitive HOF was successfully coated onto upconversion nanoparticles(UCNPs)to construct a core-shell structure named UNCPs@PFC-73-Ni.To enhance spectral overlap and maximize energy conversion efficiency,this study utilized the Er and Tm co-doped UCNPs,which can effectively convert infrared light into visible light emission thereby exciting the porphyrin shell.Subsequent investigation reveals that the composite exhibits significant photodynamic and photothermal effects under infrared light.Encouraged by its noticeable photoactivity,UCNPs@PFC-73-Ni was evaluated as an antibacterial agent against Escherichia coli.Notably,significant antibacterial efficacy was observed,highlighting the potential of UCNPs@PFC-73-Ni as an effective antibacterial agent under infrared light irradiation.

Preliminary Application of High-Frequency Ultrasound in the Differentiation of Pemphigus and Bullous Pemphigoid:An Observational Study

Objective:Ultrasonography is a diagnostic imaging technique used to visualize subcutaneous body structures for identification of possible pathologies.In this study,we aimed to explore the clinical significance of high-frequency ultrasound in differentiating the location of blisters between pemphigus and bullous pemphigoid.Methods:Eighteen patients were recruited in Department of Dermatology,Zhongda Hospital from 2020 to 2021 and divided into a pemphigus group(n=8)and a bullous pemphigoid group(n=10)according to the diagnostic criteria for each.Ultrasonographic images were collected using a 50-MHz high-frequency ultrasound system.The indexes of ultrasonic evaluation were the layer(epidermis or dermis),size,shape,internal echo,and boundary of the blister.Categorical variables are expressed as n(%),and differences were compared using Fisher’s exact test.Results:The ultrasonographic images in the pemphigus group showed an intraepidermal semi-arc or irregular anechoic or hypoechoic areas.The inferior borders were situated above the characteristic thin linear hyperechoic bands of the epidermis.A linear hypoechoic band was present at the dermoepidermal junction in some cases.In the ultrasonographic images of the bullous pemphigoid group,the linear hyperechoic bands of the epidermis were continuous and intact.An oval fluid anechoic area(subepidermal blister)was present immediately below the bands.The location of the blisters in the ultrasonographic images was significantly different between the 2 groups(P<0.001).Conclusion:High-frequency ultrasound can be used as an auxiliary means to differentiate the location of blisters between pemphigus and bullous pemphigoid.

教育数字化战略背景下教育督导模式变革与创新——基于国家智慧教育督导平台的建设实践

伴随国家进入现代化治理新时代,教育领域加快提升治理水平和治理能力,推进教育督导体制机制改革,已经成为回应时代命题的必然之举。本研究立足教育部教育数字化战略行动的大背景,结合研究团队参与国家智慧督导平台建设实践,对智慧督导的内涵特征、价值意蕴和系统要素进行了深入剖析;提出智慧督导是结合大数据和人工智能技术,变革传统督导模式以生成兼具督政、督学、评估监测等业务管理和社会公共服务“双属性”的教育治理数字化高阶形态;建构了由“数字技术、指标库、督导队伍、组织架构、管理模式”构成的智慧督导概念模型;面向数字技术赋能“提前发现问题”“主动预警报警”“分级督促整改”三大场景,阐释了“多元共治”“一键触发”“精准靶向”的智慧督导模式;结合技术发展趋势,给出了开展跨省域、区域试点示范,构建智慧督导共同体,建设人机协同智慧督导生态,以及“四位一体”协同推进智慧督导模式变革的策略建议。

基于需求图谱分析的智慧教育督导发展策略研究——以国家智慧教育督导平台建设的实践为例

国家教育数字化战略行动背景下,信息化建设进程进一步加速了教育资源融合、教育供给结构转型以及教育治理模式创新。作为教育治理体系架构下的重要组成部分,教育督导迈向“智慧化”是应然选择。如何顺应时代发展需求、顺应人民群众对教育公平与教育质量的美好诉求与向往,需要在国家、地方各级各层教育用户需求之间做好平衡、兼顾、取舍,设计一整套贴合需求的智慧教育督导体系架构——服务于教育全域突出问题的研判与解决,从而实现教育督导从单一业务管理功能转向监测分析与公众服务并重,推动教育督导治理体系和治理能力的升级,为教育提质增效保驾护航。课题组基于国家智慧教育督导平台建设的实践,面向全国督导战线干系人(省、市、区、校督导负责人、家长等)开展调研和访谈,充分利用基于语义主题发现用户需求的思路方法,采用文本挖掘技术对多源异构数据进行处理,抽取需求特征词库,并与督导业务流程建立映射关联,绘制需求图谱。通过对图谱进行释义和解构,为精准感知各级教育督导业务需求提供科学分析与决策支持,为我国智慧教育督导发展路径提供策略建议。

Synergetic effects of gold-doped copper nanowires with low Au content for enhanced electrocatalytic CO_(2)reduction to multicarbon products

As efficient catalysts of electrochemical CO_(2)reduction reaction(CO_(2)RR)towards multicarbon(C_(2+))products,Cu-based catalysts have faced the challenges of increasing the reactive activity and selectivity.Herein,we decorated the surface of Cu nanowires(Cu NWs)with a small amount of Au nanoparticles(Au NPs)by the homo-nucleation method.When the Au to Cu mass ratio is as little as 0.7 to 99.3,the gold-doped copper nanowires(Cu-Au NWs)could effectively improve the selectivity and activity of CO_(2)RR to C_(2+)resultants,with the Faradaic efficiency(FE)from 39.7%(Cu NWs)to 65.3%,the partial current density from 7.0(Cu NWs)to 12.1 mA/cm^(2) under−1.25 V vs.reversible hydrogen electrode(RHE).The enhanced electrocatalytic performance could be attributed to the following three synergetic factors.The addition of Au nanoparticles caused a rougher surface of the catalyst,which allowed for more active sites exposed.Besides,Au sites generated*CO intermediates spilling over into Cu sites with the calculated efficiency of 87.2%,which are necessary for multicarbon production.Meanwhile,the interphase electron transferred from Cu to Au induced the electron-deficient Cu,which favored the adsorption of*CO to further generate multicarbon productions.Our results uncovered the morphology,tandem,electronic effect between Cu NWs and Au NPs facilitated the activity and selectivity of CO_(2)RR to multicarbons.

Calcite U-Pb Geochronology Revealing Late Ediacaran-Early Paleozoic Hydrothermal Alteration in the Stenian-Tonian Carbonate of Northeastern North China Craton

Two calcite LA-ICP-MS U-Pb ages of 534±26 Ma(MSWD=5.9)and 456±43 Ma(MSWD=3.8)were obtained from the Nanfen Formation,Xihe Group in the southern Liaoning Prov-ince,northeastern China,which significantly postdate the theoretical depositional age of sampling hori-zon.This means they represent timing of post-depositional hydrothermal event possibly induced by syn-chronous far-field magmatism in the South Qinling.Occurrence of common Pb enriched muddy compo-nents coupled with input of"mantle"-like common Pb could account for the relatively low U contents and high common Pb contents in the dated muddy carbonates.We recommend that micro-domains of carbonates are prescreened by rapid in situ carbonate U-Pb geochronology to demonstrate whether they are of primary or secondary origin before utilizing them for chemostratigraphic study.

Tunable CO_(2)enrichment on functionalized Au surface for enhanced CO_(2)electroreduction

Electrochemical conversion of carbon dioxide(CO_(2))to higher-value products provides a forward-looking way to solve the problems of environmental pollution and energy shortage.However,the low solubility of CO_(2)in aqueous electrolytes,sluggish kinetics,and low selectivity hamper the efficient conversion of CO_(2).Here,we report a Au-based hybrid nanomaterial by modifying Au nanoparticles(NPs)with the macrocyclic molecule cucurbit[6]uril(Au@CB[6]).Au@CB[6]displays the optimal selectivity of CO,with the highest CO Faraday efficiency(FECO)reaching 99.50%at−0.6 V vs.reversible hydrogen electrode(RHE).The partial current density of CO formed by Au@CB[6]increases dramatically,as 3.18 mA/cm2 at−0.6 V,which is more than ten times as that of oleylamine-coated Au NPs(Au@OAm,0.31 mA/cm2).Operando electrochemical measurement combined with density functional theory(DFT)calculations reveals that CB[6]can gather CO_(2)and lead the increased local CO_(2)concentration near metal interface,which realizes significantly enhanced electrochemical CO_(2)reduction reaction(CO_(2)RR)performance.