Direct detection of a single[4Fe-4S]cluster in a tungsten-containing enzyme:Electrochemical conversion of CO_(2) into formate by formate dehydrogenase

The conversion of CO_(2) into fuels and valuable chemicals is one of the central topics to combat climate change and meet the growing demand for renewable energy.Herein,we show that the formate dehydrogenase from Clostridium ljungdahlii(ClFDH)adsorbed on electrodes displays clear characteristic voltammetric signals that can be assigned to the reduction and oxidation potential of the[4Fe-4S]^(2+/+)cluster under nonturnover conditions.Upon adding substrates,the signals transform into a specific redox center that engages in catalytic electron transport.ClFDH catalyzes rapid and efficient reversible interconversion between CO_(2) and formate in the presence of substrates.The turnover frequency of electrochemical CO_(2) reduction is determined as 1210 s^(-1) at 25℃ and pH 7.0,which can be further enhanced up to 1786 s^(-1) at 50℃.The Faradaic efficiency at−0.6 V(vs.standard hydrogen electrode)is recorded as 99.3%in a 2-h reaction.Inhibition experiments and theoretical modeling disclose interesting pathways for CO_(2) entry,formate exit,and OCN−competition,suggesting an oxidation-state-dependent binding mechanism of catalysis.Our results provide a different perspective for understanding the catalytic mechanism of FDH and original insights into the design of synthetic catalysts.

Hydrogenase as the basis for green hydrogen production and utilization

Hydrogenase is a paradigm of highly efficient biocatalyst for H_(2) production and utilization evolved in nature. A dilemma is that despite the high activity and efficiency expected for hydrogenases as promising catalysts for the hydrogen economy, the poor oxygen tolerance and low yield of hydrogenases largely hinder their practical application. In these years, the enigmas surrounding hydrogenases regarding their structures, oxygen tolerance, mechanisms for catalysis, redox intermediates, and proton-coupled electron transfer schemes have been gradually elucidated;the schemes, which can well couple hydrogenases with other highly efficient(in)organic and biological catalysts to build novel reactors and drive valuable reactions, make it possible for hydrogenases to find their niches. To see how scientists put efforts to tackle this issue and design novel reactors in the fields where hydrogenases play crucial roles, in this review,recent advances were summarized, including different strategies for protecting enzyme molecules from oxygen, enzyme-based assembling systems for H_(2) evolution in the photoelectronic catalysis, enzymatic biofuel cells for H_(2) utilization and storage and the efficient electricity-hydrogen-carbohydrate cycle for high-purity hydrogen and biofuel automobiles. Limitations and future perspectives of hydrogenasebased applications in H_(2) production and utilization with great impact are discussed. In addition, this review also provides a new perspective on the use of biohydrogen in healthcare beyond energy.

Tailoring the surface structures of iron oxide nanorods to support Au nanoparticles for CO oxidation

Iron oxide supported Au nanomaterials are one of the most studied catalysts for low-temperature CO oxidation.Catalytic performance not only critically depends on the size of the supported Au nanoparticles(NPs)but also strongly on the chemical nature of the iron oxide.In this study,Au NPs supported on iron oxide nanorods with different surface properties throughβ-FeOOH annealing,at varying temperatures,were synthesized,and applied in the CO oxidation.Detailed characterizations of the interactions between Au NPs and iron oxides were obtained by X-ray diffraction,transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy.The results indicate that the surface hydroxyl group on the Au/FeOOH catalyst,before calcination(Au/FeOOH-fresh),could facilitate the oxygen adsorption and dissociation on positively charged Au,thereby contributing to the low-temperature CO oxidation reactivity.After calcination at 200℃,under air exposure,the chemical state of the supported Au NP on varied iron oxides partly changed from metal cation to Au0,along with the disappearance of the surface OH species.Au/FeOOH with the highest Au0 content exhibits the highest activity in CO oxidation,among the as-synthesized catalysts.Furthermore,good durability in CO oxidation was achieved over the Au/FeOOH catalyst for 12 h without observable deactivation.In addition,the advanced identical-location TEM method was applied to the gas phase reaction to probe the structure evolution of the Au/iron oxide series of the catalysts and support structure.A Au NP size-dependent Ostwald ripening process mediated by the transport of Au(CO)x mobile species under certain reaction conditions is proposed,which offers a new insight into the validity of the structure-performance relationship.

Altitudinal patterns of stand structure and herb layer diversity of Picea schrenkiana forests in the central Tianshan Mountains,Northwest China

Altitude is a useful indicator to examine patterns of forest structure and species diversity in relation to environmental factors.In this study,the altitude patterns of forest stand structure and species diversity were analyzed across 20 plots in the Tianchi Nature Reserve,Northwest China.The results showed that mean stem height（Hm）,maximum stem height（Hmax） and mean stem diameter at breast height（Dm） of Picea schrenkiana trees all decreased significantly with increasing altitude.Potential tree height（H＊） decreased while stem taper increased significantly as altitude increased,suggesting remarkable altitudinal changes in biomass allocation between the diameter and height growth of Picea schrenkiana.Understory herbaceous richness increased significantly with increasing altitude,or with decreasing total basal area（TBA）,Hm and stand volume（Volume）.High light availability for understory herbs might account for the higher species richness at high altitude.Sorensen Index decreased significantly with the increase in altitude intervals,while the Cody Index demonstrated a converse pattern,suggesting greater differences in species composition with larger distances.

Architecture of Co-layered double hydroxide nanocages/graphene composite electrode with high electrochemical performance for supercapacitor

A facile hydrolysis method was applied to fabricate high-performance Co-layered double hydroxide（LDH）nanocages/graphene composites for supercapacitors. The materials exhibit enhanced rate capability than the counterpart electrode free of graphene while maintaining a high specific capacitance. In addition,such Co-LDH nanocages/graphene composites display an excellent cycling stability; the capacitance retention of Co-LDH nanocages/graphene composite electrode remains 90.4% after 10000 cycles at a current density of 2 A g（-1）. The integration of high capacity of double hydroxide and outstanding conductivity of graphene makes the delicately-designed composites promising candidates for electrode materials for supercapacitors.

A review of electrocatalyst characterization by transmission electron microscopy

At present, the development of highly efficient electrocatalysts with more rational control of microstructures(e.g. particle size, morphology, surface structure, and electronic structure) and chemical composition is needed and remained great challenges. Transmission electron microscopy(TEM) can offer the information about the microstructures and chemical compositions of the electrocatalysts on nano and atomic scale, which enables us to establish the synthesis-structure-performance relationship and further direct the design of new electrocatalysts with high performance. In this minireview paper, a brief introduction on the basic characterization of electrocatalysts with TEM, followed by the studying of dynamic evolution of the electrocatalysts in electrochemical reactions with identical location-TEM, is discussed.

Highly efficient base-free aerobic oxidation of alcohols over gold nanoparticles supported on ZnO-CuO mixed oxides

The design and preparation of suitable supports are of great importance for gold catalysts to attain excellent catalytic performance for alcohol oxidation.In this work,we found that ZnO-CuO mixed oxides supported gold catalysts showed much better catalytic activity for base-free aerobic oxidation of benzyl alcohol than Au/ZnO and Au/CuO catalysts,and among them Au/Zn0.7Cu0.3O displayed the best catalytic performance.In addition,the Au/Zn0.7Cu0.3O catalyst could selectively catalyze the aerobic oxidation of a wide range of alcohols to produce the corresponding carbonyl compounds with high yields under mild conditions without base.Further characterizations indicated that the outstanding catalytic performance of Au/Zn0.7Cu0.3O was correlated with the small size of Au nanoparticles(NPs),good low-temperature reducibility,high concentration of surface oxygen species,and collaborative interaction between Au NPs and mixed oxide.

Research Progress in Tomato Responses to Abiotic Stress

Tomato is a kind of vegetable with high economic benefits in protected farmland.Accounting for 30% of vegetable planting area in the entire protected farmland,tomato plays an essential role in cultivation of protected vegetable.Different abiotic stresses have different degrees of influence on growth and development,yield,and fruit quality of tomatoes.Therefore,finding out life activity rules of tomatoes under different abiotic stresses will be of great significance to breeding for stress tolerance and increasing tomato yield and income.This paper made an overview of research progress in tomato responses to abiotic stress in growth and development,physiology and biochemistry,and gene regulation.

Immunologic characteristics and predictive risk factors of primary Sjögren’s syndrome complicated with malignant lymphoma:A multicenter case-control study

To the Editor:Primary Sjögren’s syndrome(pSS)is a multi-systemic autoimmune disease characterized by the exocrine gland(mainly salivary and lacrimal glands)involvement,leading to xerostomia and xerophthalmia.[1]The course of pSS is relatively slow,but patients with pSS had higher risk of overall cancer,including malignant lymphoma(ML).[2]It is widely known that all-cause mortality rates were not increased in pSS patients as compared with healthy controls.Nonetheless,secondary lymphoproliferative disease was an important cause of excess mortality.

Near-infrared aggregation-induced emission materials:Bibliometric analysis and their application in biomedicalfield

Aggregation-induced emission(AIE)is an intriguing photophysical phenomenon,where specific materials exhibit a remarkable surge in luminescence when brought together in non-ideal solvents or within a solid matrix.Since the concept of AIE wasfirst introduced in 2001,numerous advanced applications have been gradually explored across various domains,including optics,electronics,energy,and the life sciences.Of particular note is the growing interest in the application of AIE systems with near-infrared(NIR)emissive feature in thefield of biomedicine,encompass-ing detection,imaging,and therapeutic interventions.Notably,bibliometric analysis serves as a valuable tool to provide researchers with a comprehensive understand-ing of research achievements and developmental trends in specificfields,which is crucial for academic research.Herein,we present a general bibliometric overview spanning two decades of NIR-AIE development.With the assistance of core scien-tific databases and various bibliometric software tools,we conducted a systematic analysis of annual publications and citations,the most influential countries/regions,leading authors,journals,and institutions,as well as the hot topics related to NIR applications and forward-looking predictions.Furthermore,the application of AIE with NIR properties in the biomedicalfield is also systematically reviewed.

Trace nitrogen-doped hierarchical porous biochar nanospheres:Waste corn roots derived superior adsorbents for high concentration single and mixed organic dyes removal

Seeking high performance adsorbents for highly efficient treatment of wastewater containing organic dyes has become increasingly imperative worldwide.Herein,with a specific surface area(SSA)of 2,745.4 m^(2)·g^(−1),trace N-doped porous biochar nanospheres(NPBs)are derived for the first time from affluent waste corn roots,via a hydrothermal conversion followed by a mild calcined activation by K2CO3(KC)in the presence of low virulent melamine.Melamine acts as N source and synergistic activator for significant promotion in SSA,pore volume,and surface defects.The obtained NPBs(CHC-0.5N-4KC-900)are confirmed as superior adsorbents for removal of organic dyes rhodamine B(RhB,qm=1,630.7 mg·g^(−1))and Congo red(CR,qm=1,766.2 mg·g^(−1))as well as their mixtures,within not only a low(<50 mg·L^(−1))but also a high(>50,esp.250–1500 mg·L^(−1))concentration range.The values for qm are far beyond commercially activated carbon(AC)as well as most reported biomass derived carbons,undoubtedly revealing the NPBs as great promising candidate adsorbents for disposal of real industrial wastewater.In addition,the adsorption of RhB is fitted by Langmuir,Freundlich,Temkin,and Dubinin–Radushkevich isotherm models.The kinetic analysis indicates that the adsorption before equilibrium conforms to the pseudo-second-order model,and the hydrogen bonding,electrostatic attraction,and esp.π–πinteraction have contributed to the superior adsorption performance of the NPBs.

Using waste to treat waste:Red mud induced hierarchical porousγ-AlOOH andγ-Al_(2)O_(3) microspheres as superior Pd support for catalytic reduction of 4-nitrophenol

Toward the imperative treatment of the industrial wastewater containing 4-nitrophenol(4-NP)and industrial solid waste red mud(RM),an innovative approach of“Using waste to treat waste”is developed.Valuable element Al is leached from the RM first,the resultant NaAlO_(2) solution is hydrothermally converted toγ-AlOOH hierarchical porous microspheres(RMγ-AlOOH HPMSs,average diameter:2.0μm,SBET:77.81 m^(2) g^(-1),pore volume:0.38 cm^(3) g^(-1))in the presence of urea.The subsequent mild thermal conversion results inγ-Al_(2)O_(3) hierarchical porous microspheres(RMγ-Al_(2)O_(3) HPMSs).Both of the RMγ-AlOOH and RMγ-Al_(2)O_(3) HPMSs are employed as the Pd catalyst support for the catalytic reduction of 4-NP.Particularly,the as-obtained composite Pd/RMγ-AlOOH and Pd/RMγ-Al_(2)O_(3) exhibit excellent catalytic activities with superior knor as 8204.5 and 4831.4 s^(-1) g^(-1),respectively,significantly higher than that of most Pd based catalysts.Moreover,the excellent catalytic stability and durability of the Pd/RMγ-AlOOH and Pd/RMγ-Al_(2)O_(3) within 10 successive cycles of reduction enable the present industrial solid waste RM inducedγ-AlOOH andγ-Al_(2)O_(3) HPMSs as great promising Pd catalyst support for the reduction of the industrial wastewater containing 4-NP.

Mannan-binding lectin directly interacts with Toll-like receptor 4 and suppresses lipopolysaccharide-induced inflammatory cytokine secretion from THP-1 cells

Mannan-binding lectin(MBL)plays a key role in the lectin pathway of complement activation and can influence cytokine expression.Toll-like receptor 4(TLR4)is expressed extensively and has been demonstrated to be involved in lipopolysaccharide(LPS)-induced signaling.We first sought to determine whether MBL exposure could modulate LPS-induced inflammatory cytokine secretion and nuclear factor-kB(NF-kB)activity by using the monocytoid cell line THP-1.We then investigated the possible mechanisms underlying any observed regulatory effect.Using ELISA and reverse transcriptase polymerase chain reaction(RT-PCR)analysis,we found that at both the protein andmRNAlevels,treatment withMBLsuppresses LPS-induced tumor-necrosis factor(TNF)-a and IL-12 production in THP-1 cells.An electrophoretic mobility shift assay and western blot analysis revealed that MBL treatment can inhibit LPS-induced NF-kB DNA binding and translocation in THP-1 cells.While the binding of MBL to THP-1 cells was evident at physiological calcium concentrations,this binding occurred optimally in response to supraphysiological calcium concentrations.This binding can be partly inhibited by treatment with either a soluble form of recombinant TLR4 extracellular domain or anti-TLR4 monoclonal antibody(HTA125).Activation of THP-1 cells by LPS treatment resulted in increased MBL binding.We also observed that MBL could directly bind to the extracellular domain of TLR4 in a dose-dependent manner,and this interaction could attenuate the binding of LPS to cell surfaces.Taken together,these data suggest that MBL may affect cytokine expression through modulation of LPS-/TLR-signaling pathways.These findings suggest that MBL may play an important role in both immune regulation and the signaling pathways involved in cytokine networks.

One-pot hydrothermal synthesis of hierarchical porous manganese silicate microspheres as excellent Fenton-like catalysts for organic dyes degradation

Towards bottlenecks demonstrated by typical Fenton-like catalysts in advanced oxidation processes(AOPs)for wastewater treatment,novel hierarchical porousMn^(2+)Mn_(6)^(3+)SiO_(12)(Mn_(7)SiO_(12),MSO-12)microspheres(specific surface area:434.90 m^(2)·g^(-1),pore volume:0.78 cm^(3)·g^(-1))were rationally designed and achieved via a simple one-pot hydrothermal method(150℃ and 12.0 h)without any pre-prepared templates or organic solvents,by using abundant MnCl_(2)·4H_(2)O and Na_(2)SiO_(3)·9H_(2)O as the basic raw materials.The MSO-12 microspheres are confirmed as high-efficiency Fenton-like catalysts for degradation of organic dyes(methylene blue(MeB),Rhodamine B(RhB),and methyl blue(MB))in the presence of H_(2)O_(2),with impressively high specific consumption amount of MeB(R=12.35 mg·g^(-1)·min^(-1))and extremely low leaching of Mn(Mnloss%=0.27%).Simultaneously,the synergetic effect of adsorption and degradation on the superior removal of MeB is uncovered.The excellent recycling performances,especially the satisfactory removal of MeB from the actual water bodies(e.g.,tap water and river water),as well as potential applications for degradation of RhB and MB enable the MSO-12 microspheres as a novel promising competitive candidate Fenton-like catalyst.

Analyzing the Effectiveness of Policy Implementation at the Local Level: A Case Study of Management of the 2009–2010 Drought in Yunnan Province, China

Several research efforts have focused primarily on policy implementation and improving innovative actions to address disaster risks. Discussions are ongoing on how to measure the effectiveness of policy implementation at the local level. But there is no definitive theory of effective policy implementation, and very few frameworks have been found acceptable as the basis of an analysis of the effectiveness of policy implementation, especially on droughts. Based on the 2009–2010 extreme drought in Yunnan, China, this article presents a modified framework to assess the effectiveness of policy implementation by defining policy, practice, and performance, as well as a feedback loop by which to share the lessons learned. Water conservancy projects in Luliang County and the agricultural diversity program in Longyang County in Yunnan Province were analyzed from a farmers' perspective. It was found that farmers are highly dependent on government policies and projects, and the effectiveness of policies is measured by short-term, immediate, and tangible benefits rather than long-term adaptation strategies. The results highlight the urgent need to reduce risks by developing better awareness about climate change and drought and its impacts, increased understanding of drought hazards, and implementation of appropriate measures for long-term adaptation.

Facile-fabricated iron oxide nanorods as a catalyst for hydrogenation of nitrobenzene

b-FeOOH nanorods were prepared by a poly ethylene glycol(PEG) assisted precipitation of FeCl_3·6 H_2O aqueous solution with urea. Na_2CO_3 aqueous solution was introduced to maintain their shapes under annealing. The one-dimensional porous iron oxide nanorods were synthesized successfully. The asprepared catalysts were characterized by X-ray diffraction, transmission electron microscopy, N_2 adsorption-desorption isotherms and X-ray photoelectron spectroscopy. The hydrogenation of nitrobenzene to aniline was taken as probe reaction to evaluate their catalytic performance. FeOOH(iron oxides hydroxide) nanorods, fabricated by annealing b-FeOOH nanorods at 250℃ in Ar atmosphere for 4h, exhibited high catalytic activity for the transfer hydrogenation of nitrobenzene to aniline with hydrazine hydrate as hydrogen donors.

Tailoring the surface structure of iron compounds to optimize the selectivity of 3-nitrostyrene hydrogenation reaction over Pt catalyst

Selective hydrogenation of substituted nitroarenes is an important reaction to obtain amines.Supported metal catalysts are wildly used in this reaction because the surface structure of supports can tune the properties of the supported metal nanoparticles(NPs)and promote the selectivity to amines.Herein,Pt NPs were immobilized on Fe OOH,Fe_(3)O_(4)andα-Fe_2O_(3)nanorods to synthesize a series of iron compounds supported Pt catalysts by liquid phase reduction method.Chemoselective hydrogenation of 3-nitrostyrene to 3-aminostyrene was used as probe reaction to evaluate the performance of the catalysts.The results show that Pt/Fe OOH exhibits the highest selectivity and activity.Fe OOH support with pores and-OH groups can tune the electronic structure of Pt NPs.The positive charge of Pt NPs supported on Fe OOH is key factor for improving the catalytic performance.

Natural killer cells in obstetric antiphospholipid syndrome

Antiphospholipid syndrome(APS)is a systemic autoimmune disease characterized by thrombotic or obstetric events caused by persistent antiphospholipid antibodies(aPLs),namely lupus anticoagulant,anticardiolipin antibodies,or anti-β2 glycoprotein I(anti-β2GPI)antibodies.^([1])The main target antigen in APS isβ2GPI,through which aPL binds to the cell membrane and subsequently activates membrane receptors and down-stream signal transducers.This may activate natural killer(NK)cells,leading to obstetric complications.

Artificial intelligence in rheumatoid arthritis research:A bibliometric analysis from 2004 to 2023

Background::Artificial intelligence(AI)holds promise for the screening,diagnosis,and management of patients with rheumatoid arthritis(RA).This study explores the current status of AI in RA from 2004 to 2023 using bibliometric analysis and outlines prospective research trends and directions.Methods::The Web of Science Core Collection database was searched for studies related to AI in patients with RA between 2004 and 2023.VOSviewer was used for bibliometric analysis.Results::A total of 601 articles from 65 countries,primarily the United States of America,China,and the United Kingdom,were included.The research revealed that the number of global studies on AI in RA surged in 2019,with the United States of America and China producing the highest numbers of articles.Brigham and Women's Hospital emerged as the leading research institution,whereas Frontiers in Immunology was the journal with the most articles on this topic.Keywords such as"rheumatoid arthritis,""machine learning,""artificial intelligence,"and"inflammation"were frequently used to indicate their significance in the field.Conclusions::The synergy of AI and big data can enhance screening,early diagnosis,therapeutic decision-making,and ground-up drug discovery for patients with RA.AI technology can assist rheumatologists more effectively in diagnosing and predicting personalized and efficacious therapeutic drugs early in disease progression and providing continuous monitoring.