化学•材料最新文献

{"title":"Linking Transition Metal Concentration and Oxidative Potential in PM2.5 by Ascorbic Acid Assay via Quasi-Michaelis-Menten Mechanism.","authors":"Yuhuang Cheng,Hanzhe Chen,Jian Zhen Yu","doi":"10.1021/acs.est.5c09374","DOIUrl":"https://doi.org/10.1021/acs.est.5c09374","url":null,"abstract":"Transition metals (TMs) in the ambient fine particulate matter (PM2.5) catalyze the formation of multiple reactive oxidative species (ROS), such as superoxide, hydrogen peroxide, and hydroxyl radicals, in lung lining fluid, contributing to the oxidative potential (OP) of inhaled particles. Complexation with ambient organics, particularly humic-like substances (HULIS), further modulates TM-catalyzed ROS generation by influencing electron transfer processes. While OP measurements are widely reported for both ambient and laboratory samples, the detailed catalytic mechanisms and chemical kinetics underlying TM-induced OP remain under-investigated and poorly understood. Here, we systematically investigated the OP of Fe and Cu using ascorbic acid (AA) assay under varying conditions. Reaction kinetics and studies of OP dependence on TM concentration have led us to propose a quasi-Michaelis-Menten mechanistic framework that involves a TM-AA complex as a key intermediate for OP generation in the AA assay. This mechanism explains the observed nonlinear kinetics and dose-response behavior of AA depletion and hydroxyl radical production. We also explored the mixing effects between TMs and HULIS in generating OP. These findings clarify the mechanistic link between TM concentration and OP in the AA assay and provide a foundation for OP modeling based on PM2.5 chemical composition.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"18 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145331675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In Situ Electric-Field-Induced Second Harmonic Generation (EFISH) Spectroscopy of TiO2-Passivated p-GaAs Photoelectrodes.","authors":"Rifat Shahriar,Ehsan Shamsi,Yu Yun Wang,Mehedi Hasan Himel,Sizhe Weng,Alexander Benderskii,Stephen B Cronin","doi":"10.1021/acs.jpclett.5c02440","DOIUrl":"https://doi.org/10.1021/acs.jpclett.5c02440","url":null,"abstract":"We employ in situ second harmonic generation (SHG) spectroscopy to investigate the built-in electric field in p-type GaAs semiconductor photoelectrodes. Here, the SHG signal increases linearly above and below the flat band potential, consistent with an increased built-in electric field and band bending under depletion conditions. Both SHG and Mott-Schottky measurements show a shift in the flat band potential upon deposition of a TiO2 protective layer due to TiO2 creating a hole-blocking layer. Measurements performed under illumination show the effects of band flattening both in the SHG measurements and in the photocurrent measurements. We observe an enhancement in the photovoltage of TiO2-passivated p-GaAs electrodes, which is attributed to both the increased electric field and a shift in the flat band potential. Specifically, we observe a 0.2 V shift in the SHG minimum with the addition of the TiO2 layer. Additionally, we probe band flattening in p-GaAs electrodes and show that electric-field-induced second harmonic (EFISH) signals, excited by a 430 nm tunable light-emitting diode (LED), decrease exponentially with an increasing LED power. As the light power rises, the photoinduced charge carrier density in the space-charge region increases, opposing the built-in electric field. This results in a significant reduction of the electric field, which is reflected in the decreased SHG signal. Thus, EFISH spectroscopy enables instantaneous and accurate measurement of the built-in electric field under varying electrochemical potentials and illumination conditions.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"89 1","pages":"11230-11235"},"PeriodicalIF":6.475,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145331999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ex Situ Fabrication of Superconducting Nanostructures for Low-Temperature STM","authors":"Adrian Greichgauer, Roozbeh Yazdanpanah, Alexey Taskin, Oliver Breunig, Yoichi Ando, Jens Brede","doi":"10.1021/acs.jpclett.5c02383","DOIUrl":"https://doi.org/10.1021/acs.jpclett.5c02383","url":null,"abstract":"Nanofabrication of topological insulator (TI) devices is essential for accessing edge and interface states, but conventional lithography and etching compromise the atomically clean surfaces required for scanning tunneling microscopy and spectroscopy (STM/STS). We demonstrate a fabrication strategy that combines ex situ lithographic patterning with in situ ultrahigh-vacuum cleaving and flipping, yielding atomically clean, nanopatterned TI-superconductor heterostructures suitable for STM/STS. In Design I, nanoribbons were defined by etching trenches into a TI film and capping with Nb. This enabled spectroscopy on large areas, although edge quality was limited by etch debris. In Design II, local thinning defined buried nanoribbons within a continuous TI film, producing pristine planar surfaces. STM/STS revealed well-developed superconducting gaps in the surrounding film, with suppressed gaps on the nanoribbons, consistent with vertical proximity coupling. This approach establishes a reproducible pathway for high-resolution STM/STS studies of proximitized nanostructures, providing a scalable platform for exploring topological superconductivity.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"18 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145332023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Water Environmental RNA Reveals Dose-Dependent Toxicant Responses in Fish.","authors":"Xiao Gou,Xianglin Liu,Xinxin Su,Huimin Ji,Qiong Wang,Xiaowei Zhang","doi":"10.1021/acs.est.5c08571","DOIUrl":"https://doi.org/10.1021/acs.est.5c08571","url":null,"abstract":"The health of aquatic ecosystems is threatened by numerous chemicals, posing a critical global challenge. This study aimed to establish a noninvasive monitoring approach based on water environmental RNA (eRNA). This method assesses aquatic ecological status and provides early warnings of chemical stress risks by capturing transcriptome-wide metabolic activity from organisms in ambient water. Zebrafish were exposed to chemicals (carbendazim, chlorpyrifos, and their mixture) with distinct concentrations and modes of action in aquariums. First, zebrafish-derived transcripts accounted for 1.77-4.81% of total water eRNA transcripts, with 3370 genes annotated, of which 13.94-28.53% could be tracked to specific tissues, predominantly the scale and testis, functionally enriched in metabolic and cellular processes. Furthermore, the water eRNA exhibited perturbation potencies of carbendazim that were ∼2 and ∼8 times higher than organismal RNA (oRNA) derived from the zebrafish whole body at the gene and pathway levels, respectively. Finally, zebrafish eRNA profiles distinguished chemical exposures via adaptive pathway perturbations, alongside the identification of 12 candidate biomarker genes, such as nccrp1, for future eRNA-based chemical discrimination. Overall, this study deciphered zebrafish transcriptional dynamics in water eRNA under varied chemical exposures, contributing to the methodological advance in ecotoxicology and advancing eRNA-based early warning applications in global water management.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"58 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145331673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Designing Macrocycles to Adopt Persistent, Isoenergetic Conformations.","authors":"Liam E Claton,Gretel A Stokes,Annie L Downum,Eric E Simanek","doi":"10.1021/acs.joc.5c01560","DOIUrl":"https://doi.org/10.1021/acs.joc.5c01560","url":null,"abstract":"Targeting molecules that exist as an ensemble of preorganized conformations represents a compromise between the pursuit of flexible molecules of undefined structure and rigid molecules biased toward a single conformation. Here, condensation of two self-reactive monomers quantitatively produces macrocyclic dimers that adopt persistent and structurally well-defined conformers observable using 1H NMR spectroscopy under ambient conditions. Conformers result from hindered bonds with rotational barriers of ∼18 kcal/mol. At elevated temperatures (∼75 °C), the barrier is overcome and a single species is observed by 1H NMR spectroscopy. When a single monomer is used, three conformers are obtained. When two monomers are used, ten conformers are obtained. Because these conformers exist as enantiomeric pairs, a chiral environment doubles the number of conformers accessed. Computation (CREST) identifies persistent conformations and corroborates the observation that these conformations are of similar energy.","PeriodicalId":57,"journal":{"name":"Journal of Organic Chemistry","volume":"98 1","pages":""},"PeriodicalIF":4.354,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145331783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluvial Dissolved Organic Matter Quality Modulates Microbial Nitrate Transformation: Enhanced Denitrification under Low Carbon-to-Nitrate Ratio.","authors":"Xiang Zhu,Fei Yang,Qingqing Pang,Fuquan Peng,Bin Xu,Longmian Wang,Lei Xie,Weihong Zhang,Linfeng Tian,Jun Hou,Chen Zhou,Zhengfeng Hu","doi":"10.1021/acs.est.5c07104","DOIUrl":"https://doi.org/10.1021/acs.est.5c07104","url":null,"abstract":"Dissolved organic matter (DOM), particularly the molar ratio of dissolved organic carbon (DOC) to NO3- plays a crucial role in shaping fluvial microbial NO3- transformation processes. However, the underlying mechanisms involving microbial genes remain poorly unexplored. To address this gap, six sampling campaigns were conducted in the Qingshui River, northwest China. Samples from different temporal and spatial points were categorized into three groups based on DOC:NO3- values: low (L, <0.582), medium (M, 0.582 ∼ 3.13), and high (H, >3.13). Surprisingly, despite stoichiometric models suggesting that low DOC:NO3- suppresses denitrification, our results showed the highest median abundances of denitrification genes in group L, followed by M and H. Isotope analysis confirmed denitrification as the dominant process in group L. This enhanced denitrification was linked to the higher proportion of fulvic acid-like compounds in DOM, which promoted microbial cooperation, stabilized network interactions, and maintained elevated gene abundances related to respiration and energy metabolism (especially electron transfer). Laboratory experiments further demonstrated that fulvic acid-rich DOM, even under low DOC:NO3- conditions, served as an efficient carbon source, enhancing the activities of nitrate reductase and nitric oxide reductase. These findings provide new insights into how DOM composition modulates microbial nitrate transformations, offering strategies to promote fluvial denitrification.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"41 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145331873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How the Extent of Protein Folding and Oligomerization Modulate Condensate Formation and Properties","authors":"Ilan Edelstein, Yaakov Levy","doi":"10.1021/acs.jpclett.5c02083","DOIUrl":"https://doi.org/10.1021/acs.jpclett.5c02083","url":null,"abstract":"Although proteins across the order–disorder continuum can undergo phase separation, it remains unclear how the structural states of the protein constituents influence the material properties of the resulting condensates. Here, using a coarse-grained model of a primordial peptide–RNA system, we investigate how condensates formed from ordered versus disordered peptides differ in their properties. By systematically varying the degree of foldedness and oligomerization of the peptide constituents, we find that stronger peptide–peptide interactions reduce diffusivity, whereas stronger peptide–RNA interactions destabilize the condensate. We further show that peptide conformational plasticity modulates the balance between these interactions, acting as a powerful lever for tuning the condensate properties. This work highlights how subtle changes in protein structure shape condensate architecture, dynamics, or stability and, together with experimental observations, provides a framework for understanding how the evolutionary shift from disordered to ordered peptides may have expanded the material repertoire of biomolecular condensates.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"1 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145332019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strong Association between Children's Elevated Blood Lead Levels and Lead Service Lines: A Census Tract-Level Analysis for Two Midwest Cities.","authors":"Rogelio Tornero-Velez,Nicholas Spalt,Timothy Buckley,Antonios G Poulakos,Stephanie DeFlorio-Barker,Michael Goldberg,Valerie Zartarian,Lindsay Stanek","doi":"10.1021/acs.est.5c06429","DOIUrl":"https://doi.org/10.1021/acs.est.5c06429","url":null,"abstract":"The contribution of lead service lines (LSLs) to children's blood lead levels (BLLs) has long been suggested but has been difficult to quantify due to limited LSL inventory data. This study examines the association between LSL prevalence and elevated BLLs (EBLLs; ≥5 μg/dL) among children served by the Grand Rapids Water System (GRWS) and the Greater Cincinnati Water Works (GCWW). Address-level LSL records were aggregated to the census tract level and linked with EBLL prevalence data. Strong positive correlations were observed between LSL prevalence and EBLLs in both GCWW (r = 0.71, p < 0.001; n = 195) and GRWS (r = 0.83, p < 0.001; n = 52). Linear and weighted quantile sum (WQS) regression showed that LSL prevalence was a stronger predictor of Pb exposure risk than EPA's Random Forest Models (RFv1 and RFv2) and HUD's Deteriorated Paint Index, though somewhat weaker─but comparable─to Vox's Lead Exposure Risk score. In WQS models including multiple predictors, LSL prevalence received the highest component weight for GCWW and surpassed the threshold of significance for both systems. These findings underscore the independent contribution of LSLs to children's lead exposure and support LSL replacement as an effective public health strategy.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"3 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145338625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Case for Open-Source Process Control Algorithms in Wastewater Treatment to Mitigate Greenhouse Gas Emissions: A Call to Academia for Climate Action.","authors":"Kuldip Kumar,Jonathan S Grabowy,Federico Sinche Chele,Thaís Bremm Pluth,Levi L Straka,Joseph A Kozak,Dominic A Brose","doi":"10.1021/acs.est.5c12675","DOIUrl":"https://doi.org/10.1021/acs.est.5c12675","url":null,"abstract":"","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"1 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145331870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of Electrocatalytic CO2 Reduction on MXene Materials via First-Principles Simulations","authors":"Colton Lund, Jiayi Xu, Cong Liu","doi":"10.1021/acs.jpcc.5c03901","DOIUrl":"https://doi.org/10.1021/acs.jpcc.5c03901","url":null,"abstract":"Computational studies of CO₂ reduction to yield various products were carried out on the basal plane and edges of different MXene materials. The impact of vacancies upon Mo₂TiC₂T_<i>x</i>, W₂TiC₂T_<i>x</i>, and Ti₃C₂T_<i>x</i> (T_<i>x</i> = O and OH) was also examined for both edge and basal sites. Initial calibrations were carried out to generate surfaces with optimal oxide/hydroxide ratios and proper termination sites upon which various vacancy sites were explored to ensure an accurate model of the surfaces’ resting states. From this work, Mo₂TiC₂O was determined to exhibit the lowest theoretical overpotential for methane as determined by volcano plot analyses. At a large enough vacancy concentration, the CO₂ reduction reaction (CO₂RR) is predicted to outcompete the hydrogen evolution reaction (HER) as the predominant reaction on the surface. When examining the edge of Mo₂TiC₂O, stronger CO₂ binding was exhibited to such an extent that the reaction was predicted to terminate after the generation of formate on the edge.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"200 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145332020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}