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It is a novel-effective process for realizing high-efficiency sensing and continuous gas monitoring by introducing precious metals into metal–oxide–semiconductors (MOSs). In this study, Ag is exploited to prepare surface functionalized SnO2 nanoparticles (NPs) and innovative xAg@SnO2/CsPbBr3, activating and catalyzing the gas sensing reactions on semiconductors. The results show that the precious metal Ag NPs promote the directional transport of carriers, thus improving the gas sensing performances. In addition, innovative xAg@SnO2/CsPbBr3 composites originated from Ag@SnO2 NPs and 3-mercaptopropionic acid treated all-inorganic perovskite CsPbBr3 are constructed to further accelerate electron transfer on heterointerfaces, enabling continuous and efficient monitoring of ethanolamine (EA) at room temperature. The sensing properties of Ag@SnO2/CsPbBr3 on various volatile organic compounds are investigated. Compared with pure CsPbBr3, the EA response of as-prepared 2Ag@SnO2/CsPbBr3 is obviously improved by about sevenfold. The response/recovery time is greatly shortened, besides the good stability. Another interesting result for xAg@SnO2/CsPbBr3 is the lower limit of detection of 44.43 ppb. The work demonstrates that Ag modification facilitates the adsorption/desorption rate and the response. Furthermore, the catalytic activation of noble metal Ag NPs and the synergistic interaction of SnO2/CsPbBr3 nano-heterojunctions promote EA sensing performances at room temperature. [ABSTRACT FROM AUTHOR]

Purpose: When planning guided implant surgery, highly radiopaque materials such as metals or zirconia produce streaking artifacts ('metal artifact') on cone‐beam computed tomography scans, which can impair registration of the intraoral scan. This study aimed to determine the effect of metal artifact reduction on the trueness of registration in the presence of multiple full‐coverage zirconia crowns. Materials and methods: A 3D‐printed maxillary study model was restored with 12 full‐coverage zirconia crowns and scanned with an intraoral scanner. Cone‐beam computed tomography scans of the study model were acquired, with and without activation of the metal artifact reduction algorithm. Registration of the optical scans was performed using initial point‐based registration with surface‐based refinement, and the deviation was measured at four pre‐defined dental landmarks. Welch's t‐test was used to compare the registration error for the metal artifact reduction group with the control group. Results: The average registration error was 0.519 mm (95% CI 0.507 to 0.531) with metal artifact reduction deactivated, compared to 0.478 mm (95% CI 0.460 to 0.496) without metal artifact reduction. Therefore, activation of the metal artifact reduction algorithm was associated with a 0.041 mm (95% CI 0.020 to 0.061, p < 0.001) increase in average registration error. Conclusions: The use of the metal artifact reduction algorithm slightly reduced trueness in this in vitro study. Clinicians are advised not to rely on a metal artifact reduction (MAR) algorithm for registration of a cone‐beam computed tomography scan with an intraoral scan when planning guided implant surgery in the presence of restoration artifacts. [ABSTRACT FROM AUTHOR]

This work proposes for the first time protecting–reflecting on both sides of plated mirrors and a solution to polycarbonate surface vulnerability to weathering and scratching using tungsten disulfide (WS2) by mechanical polishing. The ability of the dynamic chemical plating (DCP) technique to deposit Ag films at the nanometer scale on a polycarbonate (PC) substrate and its characteristics to be metallized is also shown. These deposits hold significant promise for concentrated solar power (CSP) applications. Complementarily, the application of WS2 as a reflective film for CSP by mechanical polishing on smooth polycarbonate surfaces is both novel and practical. This technique is innovative and scalable without needing reactants or electrical potential, making it highly applicable in real-world scenarios, including, potentially, on-site maintenance. The effects of surface morphology and adhesion, and the reflectivity parameters of the silver metallic surfaces were investigated. Wettability was investigated because it is important for polymeric surfaces in the activation and metal deposition immediately after redox reactions. The flame technique improved wettability by modifying the surface with carbonyl and carboxyl functional groups, with PC among the few industrial polymers that resisted such a part of the process. The change in the chemical composition, roughness, and wettability of the surfaces effectively improved the adhesion between the Ag film and the PC substrate. However, it did not significantly affect the adhesion between PC and WS2 and showed its possible implementation as a first surface mirror. Overall, this work provides a scalable, innovative method for improving the durability and reflectivity of polycarbonate-based mirrors, with significant implications for CSP applications. [ABSTRACT FROM AUTHOR]

The recycled conductive agent (left) was able to be nitrogen doped by nitrogen-cooled plasma treatment to become an effective ORR/OER bifunctional catalyst (right). [Display omitted] • ORR/OER catalyst is prepared using discarded Li batteries. • Cold plasma treatment leads to a larger specific surface area. • Enhanced catalyst for ORR and OER. • Zinc-air batteries achieve 640 mAh/g capacity and 92 mW cm−2 power density. • Aqueous zinc-air batteries are capable of stable charge/discharge cycles of 100 h. Considerable amount of high-value transition metals components can be recycled in spent ternary lithium-ion batteries. In this study, we utilized the conductive agent carbon black, obtained from the leaching waste resulting from the chemical recovery of spent lithium-nickel-manganese-cobalt (NCM) oxide cathode materials. This process allows us to create valuable bifunctional catalysts for the oxygen reduction reaction and oxygen evolution reaction (ORR/OER), facilitated by a facile cold plasma activation method, as a part of lithium batteries circular economy. The activated conductive agent (RCA-30) exhibited an ORR half-wave potential of 0.74 V (vs. RHE) in 0.1 mol/L KOH solution, and an OER overpotential of 360 mV at 10 mA cm-2 in 1 mol/L KOH electrolyte, owing to nitrogen doping of carbon black and activation of surface metal oxides. The complete zinc-air batteries incorporating the activated catalysts at the cathode exhibited an open circuit potential of up to 1.48 V and sustained cycling for 100 h at a current density of 5 mA cm-2. Additionally, the activated catalysts contributed to a power density of 92 mW cm-2 and a full discharge capacity of 640 mAh/g. [ABSTRACT FROM AUTHOR]

We systematically explored NO activation at metal/oxide interfaces by the combination of Sr3Ti2O7, Sr3Fe2O7, CeO2, anatase-TiO2, ZrO2, and γ-Al2O3 supports and the platinum-group metal cluster (Pd4, Pt4, and Rh4) using slab-model density functional theory calculations. These metal clusters can be strongly adsorbed at these metal oxide surfaces. The Pt4 and Rh4 clusters show larger adsorption energies than the Pd4 cluster, yet the γ-Al2O3(100) surface shows smaller adsorption energies than other metal oxide surfaces. One oxygen vacancy close to the metal cluster was constructed to evaluate the NO activation at those metal/oxide interfaces. The O atom of NO refills the oxygen vacancy after NO dissociation, while the N adatom is left on the metal cluster. The exothermic process was identified for the NO activation except for the Sr3Fe2O7 case, indicating the significant role of the interplay between the metal cluster and oxygen vacancy. [ABSTRACT FROM AUTHOR]

C−H bond activation reactions facilitate highly efficient molecular transformations without requiring pre‐activating substrates. While the majority of reported reaction systems for C−H activation rely on metal complexes, certain reactions have demonstrated unique or superior catalysis of metal nanoparticles. This Concept article seeks to delineate recent reports that examine the novel catalysis and design strategy of supported metal nanoparticles for C−H bond activation reactions. These reactions include oxidative homocoupling of arenes, dehydrogenative alkylation of benzenes, selective H/D exchange reactions, and α,β‐dehydrogenation of ketones. [ABSTRACT FROM AUTHOR]

Titanium (Ti), as a hard tissue implant, is facing a big challenge for rapid and stable osseointegration owing to its intrinsic bio-inertness. Meanwile, surface-related infection is also a serious threat. In this study, large-scale quasi-vertically aligned sodium titanate nanowire (SNW) arrayed coatings incorporated with bioactive Cu2+ ions were fabricated through a compound process involving acid etching, hydrothermal treatment (HT), and ion exchange (IE). A novel coating based on sustained ion release and a shape-preserving design is successfully obtained. Cu2+ substituted Na+ in sodium titanate lattice to generate Cu-doped SNW (CNW), which maintains the micro-structure and phase components of the original SNW, and can be efficiently released from the structure by immersing them in physiological saline (PS) solutions, ensuring superior long-term structural stability. The synergistic effects of the acid etching, bidirectional cogrowth, and solution-strengthening mechanisms endow the coating with higher bonding strengths. In vitro antibacterial tests demonstrated that the CNW coatings exhibited effective good antibacterial properties against both Gram-positive and Gram-negative bacteria based on the continuous slow release of copper ions. This is an exciting attempt to achieve topographic, hydrophilic, and antibacterial activation of metal implants, demonstrating a paradigm for the activation of coatings without dissolution and providing new insights into insoluble ceramic-coated implants with high bonding strengths. [ABSTRACT FROM AUTHOR]

Gaining mechanistic understanding of oxygen activation on metal surfaces is a topical area of research in surface science. However, direct investigation of on‐surface oxidation processes at the nanoscale and the empirical validation of oxygen activation pathways remain challenging for the conventional analytical tools. In this study, we applied tip‐enhanced Raman spectroscopy (TERS) to gain mechanistic insights into oxygen activation on bulk Au(111) surface. Specifically, oxidation of 4‐aminothiophenol (4‐ATP) to 4‐nitrothiophenol (4‐NTP) on Au(111) surface was investigated using hyperspectral TERS imaging. Nanoscale TERS images revealed a markedly higher oxidation efficiency in disordered 4‐ATP adlayers compared to the ordered adlayers signifying that the oxidation of 4‐ATP molecules proceeds via interaction with the on‐surface oxidative species. These results were further validated via direct oxidation of the 4‐ATP adlayers with H2O2 solution. Finally, TERS measurements of oxidized 4‐ATP adlayers in the presence of H2O18 provided the first empirical evidence for the generation of oxidative species on bulk Au(111) surface via water‐mediated activation of molecular oxygen. This study expands our mechanistic understanding of oxidation chemistry on bulk Au surface by elucidating the oxygen activation pathway. [ABSTRACT FROM AUTHOR]

Persulfate-based advanced oxidation processes (PS-AOPs) have been widely investigated by academia and industry due to their high efficiency and selectivity for the removal of trace organic pollutants from complex water substrates. PS-AOPs have been extensively studied for the degradation of pesticides, drugs, halogen compounds, dyes, and other pollutants. Utilizing bibliometric statistics, this review presents a comprehensive overview of persulfate-based advanced oxidation technology research over the past decade. The number of published articles about persulfate activation has steadily increased during this time, reflecting extensive international collaboration. Furthermore, this review introduces the most widely employed strategies for persulfate activation reported in the past 10 years, including carbon material activation, photocatalysis, transition metal activation, electrochemical activation, ultrasonic activation, thermal activation, and alkali activation. Next, the potential activation mechanisms and influencing factors, such as persulfate dosage during activation, are discussed. Finally, the application of PS-AOPs in wastewater treatment and in situ groundwater treatment is examined. This review summarizes the previously reported experiences of persulfate-based advanced oxidation technology and presents the current application status of PS-AOPs in organic pollution removal, with the aim of avoiding misunderstandings and providing a solid foundation for future research on the removal of organic pollutants. [ABSTRACT FROM AUTHOR]

This work focuses on the comparison of H2 evolution in the hydrolysis of boron-containing hydrides (NaBH4, NH3BH3, and (CH2NH2BH3)2) over the Co metal catalyst and the Co3O4-based catalysts. The Co3O4 catalysts were activated in the reaction medium, and a small amount of CuO was added to activate Co3O4 under the action of weaker reducers (NH3BH3, (CH2NH2BH3)2). The high activity of Co3O4 has been previously associated with its reduced states (nanosized CoBn). The performed DFT modeling shows that activating water on the metal-like surface requires overcoming a higher energy barrier compared to hydride activation. The novelty of this study lies in its focus on understanding the impact of the remaining cobalt oxide phase. The XRD, TPR H2, TEM, Raman, and ATR FTIR confirm the formation of oxygen vacancies in the Co3O4 structure in the reaction medium, which increases the amount of adsorbed water. The kinetic isotopic effect measurements in D2O, as well as DFT modeling, reveal differences in water activation between Co and Co3O4-based catalysts. It can be assumed that the oxide phase serves not only as a precursor and support for the reduced nanosized cobalt active component but also as a key catalyst component that improves water activation. [ABSTRACT FROM AUTHOR]

As the widely used ultraviolet (UV) filter, Ensulizole (ELZ), has been proven as an environmental hormone, development of useful techniques for eliminating ELZ is imperative. Since SO4·−-based oxidation technologies are promising for treating emerging contaminants, and cobalt (Co) appears to be an extremely useful catalyst for monopersulfate (MPS) activation, that would be critical to construct advantageous cobaltic catalyst of MPS activation. A unique activator would be derived from a special metal organic framework ([Co]pyrazine[Ni(CN)4]) which is carbonized to become a nanocluster comprised of CoNi alloy nanoparticles (NPs) confined in carbon nanospheres, and nanotubes, forming CoNi@Carbon (CNC). Such a CNC nanocomposite would exhibit several promising properties: (1) as Co is the extremely effective metal for MPS activation, CoNi is expected for offering superior performance for activating MPS; (2) high magnetization of CoNi alloy would equip CNC with a magnetically-controllability; (3) CoNi encapsulated in carbon is guarded to enhance its reusability; (4) the interlaced configurations of CNC also make it to show higher active sites for MPS activation. Thus, CNC exhibits a significantly stronger activating capability than Co3O4, which is the conventional heterogeneous catalyst for MPS. CNC/MPS also displays a lower activation energy (Ea) for ELZ degradation than literatures, showing advantages of CNC. Mechanisms for MPS activation and ELZ degradation were also elucidated to further understand elimination process of ELZ by MOF-derived cobaltic catalysts. [ABSTRACT FROM AUTHOR]

Commercial zinc metal powder requires activation for consistent and reliable use as a reductant in the formation of organozinc reagents from organohalides, and for the avoidance of supplier and batch‐to‐batch variability. However, the impact of activation methods on the reaction environments of subsequent intermediates has been unknown. Herein, a fluorescence lifetime imaging microscopy (FLIM) method is developed to bridge this knowledge gap, by imaging and examining reaction intermediates on zinc metal that has been activated by pretreatment through different common methods (i. e., by chemical activation with TMSCl, dibromoethane, or HCl; or by mechanical activation). The group of chemical activating agents, previously thought to act similarly by removing oxide layers, are here shown to produce markedly different reaction environments experienced by subsequent oxidative‐addition intermediates from organohalides – data uniquely available through FLIM's ability to detect small quantities of intermediates in situ coupled with its microenvironmental sensitivity. These different microenvironments potentially give rise to different rates of formation, subsequent solubilization, and reactivity, despite the shared "[RZnX]" molecular structure of these intermediates. This information revises models for methods development for oxidative addition to currently sluggish metals beyond zinc by establishing diverse outcomes for pretreatment activation methods that were previously considered similar. [ABSTRACT FROM AUTHOR]

Exploring efficient non-precious metal sulfides as electrocatalysts for the hydrogen evolution reaction (HER) is crucial. Cobalt disulfide (CoS 2) has gained attention for its favorable intrinsic activity, impressive metal conductivity, and cost-effectiveness. However, the weak adsorption of H* at the sulfur (S) sites on the surface of CoS 2 leaves room for enhancing its HER intrinsic activity. Vacancy engineering emerges as a valuable strategy to modulate the local charge density, optimizing hydrogen adsorption free energy and catalytic performance in HER. Taking advantage of plasma technology, known for its rapid and efficient defect creation, we synthesized porous CoS 2 nanowire arrays enriched with S vacancies (V s -CoS 2 /CC) through Ar plasma treatment. Notably, at a current density of 10 mA cm−2, V s -CoS 2 /CC exhibits a lower overpotential (170 mV) compared to pure CoS 2 /CC (236 mV). Furthermore, V s -CoS 2 /CC demonstrates exceptional electrochemical stability. Experimental data and density functional theory calculations jointly reveal that introducing S vacancies reduces local charge density around S atoms, activating inert sulfur sites and enhancing the intrinsic activity of CoS 2 for HER. This study introduces a novel concept of defect-engineered activation in metal compound catalysts, employing a plasma approach to advance HER performance. [Display omitted] • By introducing V s through plasma treatment, V s -CoS 2 /CC is obtained. • V s -CoS 2 /CC exhibits excellent HER catalytic performance. • The introduction of V s activates the inert S sites in CoS 2. [ABSTRACT FROM AUTHOR]

Metal‐based drugs currently dominate the field of chemotherapeutic agents; however, achieving the controlled activation of metal prodrugs remains a substantial challenge. Here, we propose a universal strategy for the radiation‐triggered activation of metal prodrugs via nanosurface energy transfer (NSET). The core–shell nanoplatform (Ru‐GNC) is composed of gold nanoclusters (GNC) and ruthenium (Ru)‐containing organic–inorganic hybrid coatings. Upon X‐ray irradiation, chemotherapeutic Ru (II) complexes were released in a controlled manner through a unique NSET process involving the transfer of photoelectron energy from the radiation‐excited Ru‐GNCs to the Ru‐containing hybrid layer. In contrast to the traditional radiation‐triggered activation of prodrugs, such an NSET‐based system ensures that the reactive species in the tumor microenvironment are present in sufficient quantity and are not easily quenched. Additionally, ultrasmall Ru‐GNCs preferably target mitochondria and profoundly disrupt the respiratory chain upon irradiation, leading to radiosensitization by generating abundant reactive oxygen species. Consequently, Ru‐GNC‐directed radiochemotherapy induces immunogenic cell death, resulting in significant therapeutic outcomes when combined with the programmed cell death‐ligand 1 (PD−L1) checkpoint blockade. This NSET strategy represents a breakthrough in designing radiation‐triggered nanoplatforms for metal‐prodrug‐mediated cancer treatment in an efficient and controllable manner. [ABSTRACT FROM AUTHOR]

Murine norovirus (MNV) undergoes extremely large conformational changes in response to the environment. The T = 3 icosahedral capsid is composed of 180 copies of ~58-kDa VP1 comprised of N-terminus (N), shell (S), and C-terminal protruding (P) domains. At neutral pH, the P domains are loosely tethered to the shell and float ~15 Å above the surface. At low pH or in the presence of bile salts, the P domain drops onto the shell and this movement is accompanied by conformational changes within the P domain that enhance receptor interactions while blocking antibody binding. While previous crystallographic studies identified metal binding sites in the isolated P domain, the ~2.7-Å cryo-electron microscopy structures of MNV in the presence of Mg2+ or Ca2+ presented here show that metal ions can recapitulate the contraction observed at low pH or in the presence of bile. Further, we show that these conformational changes are reversed by dialysis against EDTA. As observed in the P domain crystal structures, metal ions bind to and contract the G’H’ loop. This movement is correlated with the lifting of the C’D’ loop and rotation of the P domain dimers about each other, exposing the bile salt binding pocket. Isothermal titration calorimetry experiments presented here demonstrate that the activation signals (bile salts, low pH, and metal ions) act in a synergistic manner that, individually, all result in the same activated structure. We present a model whereby these reversible conformational changes represent a uniquely dynamic and tissue-specific structural adaptation to the in vivo environment. IMPORTANCE The highly mobile protruding domains on the calicivirus capsids are recognized by cell receptor(s) and antibodies. At neutral pH, they float ~15 Å above the shell but at low pH or in the presence of bile salts, they contract onto the surface. Concomitantly, changes within the P domain block antibody binding while enhancing receptor binding. While we previously demonstrated that metals also block antibody binding, it was unknown whether they might also cause similar conformational changes in the virion. Here, we present the near atomic cryo-electron microscopy structures of infectious murine norovirus (MNV) in the presence of calcium or magnesium ions. The metal ions reversibly induce the same P domain contraction as low pH and bile salts and act in a synergistic manner with the other stimuli. We propose that, unlike most other viruses, MNV facilely changes conformations as a unique means to escape immune surveillance as it moves through various tissues. [ABSTRACT FROM AUTHOR]

The effect of metal nitrates on the activation of anthracite combustion process has been studied. Fe(NO3)2 · 9H2O and Cu(NO3)2 · 3H2O were used as nitrates in an amount of 5 wt% applied to anthracite powder (fraction less than 0.1 mm) by incipient wetness impregnation. Using scanning electron microscopy and EDX mapping, it was found that using this method of applying the additive makes it possible to achieve high dispersion and uniform distribution in the fuel composition. The characteristics of oxidation, ignition, and combustion were studied using thermal analysis methods and high-speed video recording in the combustion chamber at a temperature of 800°C. It was found that the use of metal nitrates contributes to an increase in the reactivity of anthracite as evidenced by a decrease in the temperature of the intensive oxidation beginning (ΔTi) by 23–84°C and the ignition delay time (Δti) by 0.9–2.2 seconds. The greatest effect of changing the reactivity of anthracite was recorded in the case of using copper nitrate additive. The use of nitrates also contributed to the decrease in the resulting fuel underburning (from 3.5 to 0.4 wt%) and gas-phase CO compounds (by 31–53%). At the early stages, combustion process of modified samples was accompanied by periodic formation of micro-explosions, which led to the activation and development of the particle surface. [ABSTRACT FROM AUTHOR]

The activation procedures of metals and alloys, crucial for hydrogen absorption, pose a significant challenge in the large-scale application of metal hydrides. This study introduces, for the first time, the Pulsed Laser Activation (PLA) method for hydrogen storage alloys. We demonstrated that the hydrogen storage ability of an aged (exposed to air for 30 days) Ti 11 V 30 Nb 28 Cr 31 body-centered cubic alloy can be restored by scanning the sample with a nanosecond pulsed laser for only 3 min. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS) analyses were conducted to investigate structural features that changed in the Ti 11 V 30 Nb 28 Cr 31 samples after ageing and after the PLA treatment. Surface remelting, the formation of oxide layers, and crack formation appear to be factors influencing the hydrogen storage ability of the Ti 11 V 30 Nb 28 Cr 31 alloy activated via PLA. While the mechanisms involved in the PLA are not clear yet, this procedure paves the way for the development of activation methods based on laser-metal interactions that can be easily applied to metals and alloys for hydrogen storage systems. • The novel Pulsed Laser Activation Method (PLA) is introduced. • PLA is effective to retore the hydrogen storage ability of alloys exposed to air. • The PLA method was tested in the Ti 11 V 30 Nb 28 Cr 31 alloy exposed to air for 30 days. • The changes on the alloy surface caused by the PLA method were investigated. [ABSTRACT FROM AUTHOR]

Dimers and oligomers of alkenes represent a category of compounds that are in great demand in diverse industrial sectors. Among the developing synthetic methods, the catalysis of alkene dimerization and oligomerization using transition metal salts and complexes is of undoubted interest for practical applications. This approach demonstrates substantial potential, offering not only elevated reaction rates but also precise control over the chemo-, regio-, and stereoselectivity of the reactions. In this review, we discuss the data on catalytic systems for alkene dimerization and oligomerization. Our focus lies in the analysis of how the activity and chemoselectivity of these catalytic systems are influenced by various factors, such as the nature of the transition metal, the ligand environment, the activator, and the substrate structure. Notably, this review particularly discusses reaction mechanisms, encompassing metal complex activation, structural and dynamic features, and the reactivity of hydride intermediates, which serve as potential catalytically active centers in alkene dimerization and oligomerization. [ABSTRACT FROM AUTHOR]

A biradical cyclic alkyl(amino)carbene-stabilised 9,10-diboraanthracene (DBA) activates small molecules such as hydrogen, phenyl azide or TEMPO (2,2,6,6-tetramethylpiperidin-1-oxyl) across its two boron atoms, while reactions with [(MeCN)3M(CO)3] (M = Cr, Mo, W) yield the first half-sandwich DBA complexes of the form [(η6-DBA)M(CO)3]. [ABSTRACT FROM AUTHOR]

Reaction of complex [TpMe2Ir(η4-CH2＝C(Me)C(Me)＝C2)] (1) with a series of aromatic ketones at 130 °C renders, by means of a selective ortho-CH activation, Ir(III)-metallacycles 2–5, which display an Ir–H bond. When [TpMe2Ir(C6H5)2N2] (6) is treated with 2-(trifluoromethyl)acetophenone and 2-fluoroacetophenone at 80 °C, the formation of dimeric (7) and trimeric architectures (8) is achieved through the meta- and para-CH activation of the aromatic ketone, respectively. The generation of complexes 2–5 is proposed to occur by the initial formation of Ir(III) η1-ketone adducts as key intermediates, followed by aromatic CH activations and the release of a butadiene ligand. The formation of complexes 7 and 8 involves an assisted process in which a metal center activation of the less sterically hindered C–H bond of the aromatic ketone takes place (releasing a benzene molecule), followed by the coordination of the carbonyl group, which generates the respective dimeric and trimeric structures. Complexes 7 and 8 are efficient catalysts for the transfer hydrogenation of ketones and aldehydes using isopropanol as the hydrogen source. All complexes have been fully characterized by NMR spectroscopy, FT-IR, elemental analysis and, in the cases of 7 and 8, X-ray crystallography. Details of the reaction conditions, isolation of the products, and proposals for the pathways of formation of complexes 2–5 and 7–8 are discussed. [ABSTRACT FROM AUTHOR]

In this study, comprehensive analysis was performed on natural pumice stone from the Bitlis region of Eastern Anatolia with regard to the removal of nickel(Ni). In terms of various calculation models involving textural parameters (e.g., surface area, pore volume, particle size), the surface area of the Bitlis pumice samples obtained was 1.3491 m²/g Brunauer-Emmett-Teller model, 1.3719 m²/g Barrett-Joyner-Halenda model, and 16.0137 m²/g Langmuir model, whereas, the particle size was 4,447 nm. Fourier-transform infrared spectroscopy analysis also showed that in the region of 1,200-950 cm-1 there was a band (and shoulder) of symmetric and asymmetric stretching of the Si-O-Si bond. Accordingly, based on the kinetic, equilibrium, and thermodynamic studies of Ni(II) adsorption by Bitlis pumice from aqueous solutions, in order not to affect the heavy metal activation in the adsorption of Ni heavy metal with Bitlis pumice. Experiments were carried out at pH 7, using 1 g of pumice and 120 min at an input concentration of 3 mg/L Ni. 99% removal was achieved during contact time. The best removal efficiency of Ni(II) (99%) was obtained with an adsorbent dosage of 3 mg/L, pH 7 with a contact time of 120 min. This involved the use of the Langmuir isotherm model (R² = 0.99). These processes were interpreted chemically with the use of the second-order pseudo-kinetic model (R² = 0.99). [ABSTRACT FROM AUTHOR]

[Display omitted] While transition metals are useful for activating monopersulfate (MPS) to degrade contaminants, bimetallic alloys exhibit stronger catalytic activities owing to several favorable effects. Therefore, even though Co is an efficient metal for MPS activation, CoFe alloys are even more promising heterogeneous catalysts for MPS activation. Immobilization/embedment of CoFe alloy nanoparticles (NPs) onto hetero-atom-doped carbon matrices appears as a practical strategy for evenly dispersing CoFe NPs and enhancing catalytic activities via interfacial synergies between CoFe and carbon. Herein, N -doped carbon-embedded CoFe alloy (NCCF) is fabricated here to exhibit a unique hollow-engineered nanostructure and the composition of CoFe alloy by using Co-ZIF as a precursor after the facile etching and Fe doping. The Fe dopant embeds CoFe alloy NPs into the hollow-structured N -doped carbon substrate, enabling NCCF to possess the higher mesoscale porosity, active N species as well as more superior electrochemical properties than its analogue without Fe dopants, carbon matrix-supported cobalt (NCCo). Thus, NCCF exhibits a considerably larger activity than NCCo and the benchmark catalyst, Co 3 O 4 NP, for MPS activation to degrade an environmental hormone, dihydroxydiphenyl ketone (DHPK). Besides, NCCF + MPS shows an even lower activation energy for DHPK degradation than literatures, and retains its high efficiency for eliminating DHPK in different water media. DHPK degradation pathway and ecotoxicity assessment are unraveled based on the insights from the computational chemistry, demonstrating that DHPK degradation by NCCF + MPS did not result in the formation of toxic and highly toxic by-products. These features make NCCF a promising heterogeneous catalyst for MPS activation to degrade DHPK. [ABSTRACT FROM AUTHOR]

The main mechanisms of flotation activation by ions of metals are discussed and critically analyzed. It is shown that ions of metals can be both activators and depressants of flotation. Based on the mechanism of physisorption, it is revealed when metals act as activators and depressants. A method is proposed to stimulate selectivity of extraction of a target mineral in case of undesirable activation of flotation of associate components. The studies can be useful in selection of metal–activator, ratio of concentrations of activator and collector and pH of flotation system. [ABSTRACT FROM AUTHOR]

The electrocatalytic sulfur reduction reaction (SRR) would allow the production of renewable high‐capacity rechargeable lithium‐sulfur (Li‐S) batteries using sustainable and nontoxic elemental sulfur as a cathode material, but its slow reaction rate causes a serious shuttle effect and dramatically reduces the capacity. We found that a catalyst composed of Pd nanoparticles supported by ordered mesoporous carbon (Pd/OMC) had a high reaction rate in the SRR, and a Li‐S battery assembled with this catalyst had a low shuttle constant of 0.031 h−1 and a high‐rate performance with a specific capacity of 1527 mAh g−1 at 0.1 C which is close to the theoretical value. The high activity of Pd/OMC with a d‐orbital vacancy of 0.87 e was predicted from a volcano relationship between the d charge for the metal and the adsorption activation entropy and reaction rate for the SRR by examining Pd, Au, Pt, Rh, and Ru transition‐metal nanocatalysts. The strategy of using a single electronic structure descriptor to design high‐efficiency SRR catalysts has suggested a way to produce practical Li‐S batteries. [ABSTRACT FROM AUTHOR]

Experimental investigations on lightweight connections as a basis for seismic design Trapezoidal profiles or sandwich elements are often used as building envelope for industrial and commercial buildings. The low dead weight of the building envelope in lightweight metal construction offers a clear advantage over other construction methods in the event of an earthquake. However, the ductile properties cannot be taken into account in the verification at present, as the corresponding regulations and underlying investigations regarding the dynamic properties of the lightweight metal construction elements and the connections are missing. It is to be determined to what extent the roof and wall elements, which initially only have a space‐enclosing function, assume a stiffening function as a diaphragm and thus reduce the load on the primary load‐bearing structure and the stiffening elements. This depends on the stiffness ratio of the mentioned components. In order to develop a design procedure in case of an earthquake, investigations are being carried out on connections as part a current FOSTA research project. First, the stiffness of the connections is determined by means of static tests. For the dynamic properties, cyclic tests with increasing deformation are carried out. Based on the test results, suitable engineering models are to be developed that enable the activation of the lightweight metal construction elements for the energy dissipation during earthquake loading. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis and characterization of two manganese tricarbonyl complexes, MnI(HL)(CO)3Br (1 a‐Br) and MnI(MeL)(CO)3Br (1 b‐Br) (where HL=2‐(2'‐pyridyl)benzimidazole; MeL=1‐methyl‐2‐(2'‐pyridy)benzimidazole) and assayed their electrocatalytic properties for CO2 reduction. A redox‐active pyridine benzimidazole ancillary ligand in complex 1 a‐Br displayed unique hydrogen atom transfer ability to facilitate electrocatalytic CO2 conversion at a markedly lower reduction potential than that observed for 1 b‐Br. Notably, a one‐electron reduction of 1 a‐Br yields a structurally characterized H‐bonded binuclear Mn(I) adduct (2 a') rather than the typically observed Mn(0)‐Mn(0) dimer, suggesting a novel method for CO2 activation. Combining advanced electrochemical, spectroscopic, and single crystal X‐ray diffraction techniques, we demonstrate the use of an H‐atom responsive ligand may reveal an alternative, low‐energy pathway for CO2 activation by an earth‐abundant metal complex catalyst. [ABSTRACT FROM AUTHOR]

The transition metal frustrated Lewis pair compounds [(Cym)M(κ3S,P,N-HL1)][SbF6] (Cym = η6-p-MeC6H4iPr; H2L1 = N-(p-tolyl)-N′-(2-diphenylphosphanoethyl)thiourea; M = Ru (5), Os (6)) have been prepared from the corresponding dimer [{(Cym)MCl}2(μ-Cl)2] and H2L1 by successive chloride abstraction with NaSbF6 and AgSbF6 and NH deprotonation with NaHCO3. Complexes 5 and 6 and the previously reported phosphano–guanidino compounds [(Cym)M(κ3P,N,N′-HL2)][SbF6] [H2L2 = N,N′-bis(p-tolyl)-N′′-(2-diphenylphosphanoethyl) guanidine; M = Ru (7), Os (8)] and pyridinyl–guanidino compounds [(Cym)M(κ3N,N′,N′′-HL3)][SbF6] [H2L3 = N,N′-bis(p-tolyl)-N′′-(2-pyridinylmethyl) guanidine; M = Ru (9), Os (10)] heterolytically activate H2 in a reversible manner affording the hydrido complexes [(Cym)MH(H2L)][SbF6] (H2L = H2L1; M = Ru (11), Os (12); H2L = H2L2; M = Ru (13), Os (14); H2L = H2L3; M = Ru (15), Os (16)). DFT calculations carried out on the hydrogenation of complex 7 support an FLP mechanism for the process. Heating 9 and 10 in methanol yields the orthometalated complexes [(Cym)M(κ3N,N′,C-H2L3-H)][SbF6] (M = Ru (17), Os (18)). The phosphano–guanidino complex 7 activates deuterated water in a reversible fashion, resulting in the gradual deuteration of the three cymene methyl protons through sequential C(sp3)–H bond activation. From DFT calculations, a metal–ligand cooperative reversible mechanism that involves the O–H bond activation and the formation of an intermediate methylene cyclohexenyl complex has been proposed. Complexes 5–10 catalyse the hydrogenation of the C＝C double bond of styrene and a range of acrylates, the C＝O bond of acetophenone and the C＝N bond of N-benzylideneaniline and quinoline. The C＝C double bond of methyl acrylate adds to catalyst 9, affording complex 19 in which a new ligand exhibiting a fac κ3N,N′,C coordination mode has been incorporated. [ABSTRACT FROM AUTHOR]

A novel and efficient synthetic method utilizing CBr4 as a thiophilic reagent to facilitate one-pot oxidative condensation of amines with N,N′-disubstituted thioureas affording diverse set of guanidine derivatives is reported. The present protocol offers a valid alternative to the classical method involving toxic heavy metal salts activation due to the use of an easily available, cheap, and environmentally genial reagent, CBr4. The salient features of this protocol are its inexpensiveness, simple reaction conditions, easy purification of the products, and high yields. [ABSTRACT FROM AUTHOR]

Interactions between negatively charged bitumen and fine solids under oil sands extraction conditions were simulated using mature fine tailings (MFT) and hydrocarbon oil with dissolved carboxylic acids. Their attachment induced by cation activation was evaluated with different types of cations by simple dynamic attachment tests. The results revealed that solid hydrophobization by adsorbing surfactants was key for oil–solid attachment. Activation by multivalent metal cations was due to surface precipitation of metal hydroxides, followed by chemisorbing anionic surfactants on metal‐activated solids to form metal carboxylate complexes/precipitates, thereby hydrophobizing the solids. Activation by cationic surfactants depended on their hydrocarbon chain lengths. For short hydrocarbon chains, where hydrophobic interaction is weaker than electrostatic interaction between the added cationic and anionic surfactants, the added cations promote the adsorption of anionic surfactants by electrostatic interaction to render the solids hydrophobic. For long hydrocarbon chains where hydrophobic interaction is stronger than electrostatic interaction between the added cationic and anionic surfactants, the adsorption of anionic surfactants occurs through the hydrophobic association of the hydrocarbon chains, posing the head group towards water, thereby making the solids less hydrophobic. Activation by cationic flocculants was purely physical (hydrogen bonding and electrostatic): when the solids were turned positive by the added cationic flocculants, the added anionic surfactants then adsorbed onto the solids to render them hydrophobic. It appeared that soluble multivalent metal species (e.g., Ca2+ and Mg2+) were much less harmful to bitumen extraction than those heavy metals coated on the solids, either in the form of surface precipitates or hydrolyzed ionic species. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The Haber‐Bosch process, which is used for ammonia (NH3) synthesis, requires vast amounts of energy, accounting for approximately 1%—2% of the world's annual energy consumption. Therefore, researchers in both industry and academia are interested in developing sustainable and environmentally friendly methods for synthesizing nitrogenous compounds at ambient conditions using renewable energy sources such as visible light. While several examples of thermal activation of dinitrogen molecules have been demonstrated using various transition metals and ligand frameworks, the use of light to weaken or split the strong N—N bond has been less explored. This article presents an overview of molecular complexes capable of dinitrogen photocleavage and provides mechanistic insights into the photoactivation process through experimental and theoretical studies. We believe this review will provide readers with an in‐depth understanding of the current state‐of‐the‐art and future research perspectives, particularly in the use of visible light for dinitrogen activation and transformation. [ABSTRACT FROM AUTHOR]

Molybdenum supported on zeolites has been extensively studied as a catalyst for methane dehydroaromatization. Despite significant progress, the actual intermediates and particularly the first C-C bond formation have not yet been elucidated. Herein we report evolution of methyl radicals during non-oxidative methane activation over molybdenum single sites, which leads selectively to value-added chemicals. Operando X-ray absorption spectroscopy and online synchrotron vacuum ultraviolet photoionization mass spectroscopy in combination with electron microscopy and density functional theory calculations reveal the essential role of molybdenum single sites in the generation of methyl radicals and that the formation rate of methyl radicals is linearly correlated with the number of molybdenum single sites. Methyl radicals transform to ethane in the gas phase, which readily dehydrogenates to ethylene in the absence of zeolites. This is essentially similar to the reaction pathway over the previously reported SiO2 lattice-confined single site iron catalyst. However, the availability of a zeolite, either in a physical mixture or as a support, directs the subsequent reaction pathway towards aromatization within the zeolite confined pores, resulting in benzene as the dominant hydrocarbon product. The findings reveal that methyl radical chemistry could be a general feature for metal single site catalysis regardless of the support (either zeolites MCM-22 and ZSM-5 or SiO2) whereas the reaction over aggregated molybdenum carbide nanoparticles likely facilitates carbon deposition through surface C-C coupling. These findings allow furthering the fundamental insights into non-oxidative methane conversion to value-added chemicals. Understanding of the direct methane conversion mechanism is essential for further development of efficient catalysts. Here, authors demonstrate a general methyl radical chemistry for metal single site catalysis regardless of the support (either zeolite or SiO2) in non-oxidative methane activation. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The Haber‐Bosch process, which is used for ammonia (NH3) synthesis, requires vast amounts of energy, accounting for approximately 1%—2% of the world's annual energy consumption. Therefore, researchers in both industry and academia are interested in developing sustainable and environmentally friendly methods for synthesizing nitrogenous compounds at ambient conditions using renewable energy sources such as visible light. While several examples of thermal activation of dinitrogen molecules have been demonstrated using various transition metals and ligand frameworks, the use of light to weaken or split the strong N—N bond has been less explored. This article presents an overview of molecular complexes capable of dinitrogen photocleavage and provides mechanistic insights into the photoactivation process through experimental and theoretical studies. We believe this review will provide readers with an in‐depth understanding of the current state‐of‐the‐art and future research perspectives, particularly in the use of visible light for dinitrogen activation and transformation. [ABSTRACT FROM AUTHOR]

Porous Ni-doped copper oxide (NCO) photocatalyst has been produced using chemical activation and metal doping techniques. Structural, optical, morphological, and electrical analyses were performed on copper oxide (CO) and porous NCO photocatalysts. The monoclinic-phased, UV/Vis light-triggered, electrically conductive, and porous-surfaced NCO photocatalyst was successfully synthesized, according to a detailed physicochemical investigation. The photo-decomposition abilities of synthetic porous NCO and counterpart CO photocatalysts were investigated and compared using Allura red (AR). According to the photocatalytic study, the porous NCO photocatalyst outperformed its counterpart (CuO) and eliminated 91.4% (adsorption: 18%; decomposition: 79%) of the AR dye in 48 min. Over the porous NCO photocatalyst, the AR dye disintegrated at a rate of 0.024 min−1, which is more than 1.84 times quicker than the rate of disintegration over the CO photocatalyst. The porous NCO photocatalyst, as synthesized, preserved 88% of its photocatalytic activity after five recyclability tests and had remarkable electron-hole separation activity, according to reusability tests and transient-photocurrent measurements. Also, the radical capture experiment suggested that superoxide and hydroxyl are important for porous NCO's photocatalytic activity. According to the findings of this research, the synthesis of ferromagnetic metal-doped and porous semiconductive materials has a great potential for azo dye breakdown, which makes it an efficient, cost-effective, and environmentally acceptable solution for the clean-up of polluted water. [Display omitted] [ABSTRACT FROM AUTHOR]

The development of effective catalysts for the pyrolysis of light hydrocarbons with the production of carbon nanomaterials represents a relevant direction. In the present work, the influence of copper addition on performance of a self-dispersed Ni-catalyst and structural features of the obtained carbon nanofibers (CNFs) was studied. The precursors of Ni and Ni-Cu catalysts were prepared by activation of metal powders in a planetary mill. During contact with the C2H4/H2 reaction mixture, a rapid disintegration of the catalysts with the formation of active particles catalyzing the growth of CNFs has occurred. The kinetics of CNF accumulation during ethylene decomposition on Ni- and Ni-Cu catalysts was studied. The effect of temperature on catalytic performance was explored and it was shown that introduction of copper promotes 1.5–2-fold increase in CNFs yield in the range of 525–600 °C; the maximum CNFs yield (100 g/gcat and above, for 30-min reaction) is reached on Ni-Cu-catalyst at 575–600 °C. A comparative analysis of the morphology and structure of CNF was carried out using electron microscopy methods. The growth mechanism of carbon filaments in the shape of "railway crossties" on large nickel crystals (d > 250 nm) was proposed. It was found that the addition of copper leads to a decrease in the bulk density of the carbon product from 40–60 to 25–30 g/L (at T = 550–600 °C). According to the low-temperature nitrogen adsorption data, specific surface area (SSA) of CNF samples (at T < 600 °C) lies in the range of 110–140 m2/g, regardless of the catalyst composition; at T = 600 °C the introduction of copper contributed to an increase in the specific surface of CNF by 100 m2/g. [ABSTRACT FROM AUTHOR]

The laser surface modification of metallic implants presents a promising alternative to other surface modification techniques. A total of four alloyed metallic biomaterials were used for this study: medical steel (AISI 316L), cobalt–chromium–molybdenum alloy (CoCrMo) and titanium alloys (Ti6Al4V and Ti6Al7Nb). Samples of metallic biomaterials after machining were subjected to polishing or laser modification in two different versions. The results of surface modification were documented using SEM imaging and roughness measurement. After modification, the samples were sterilized with dry hot air, then exposed to citrate blood, washed with PBS buffer, fixed with glutaraldehyde, sputtered with a layer of gold and imaged using SEM to enable the quantification of adhered, activated and aggregated platelets on the surface of biomaterial samples. The average total number, counted in the field of view, of adhered platelets on the surfaces of the four tested biomaterials, regardless of the type of modification, did not differ statistically significantly (66 ± 81, 67 ± 75, 61 ± 70 and 57 ± 61 for AISI 316L, CoCrMo, Ti6Al4V and Ti6Al7Nb, respectively) and the average number of platelet aggregates was statistically significantly higher (p < 0.01) on the surfaces of AISI 316L medical steel (42 ± 53) and of the CoCrMo alloy (42 ± 52) compared to the surfaces of the titanium alloys Ti6Al4V (33 ± 39) and Ti6Al7Nb (32 ± 37). Remaining blood after contact was used to assess spontaneous platelet activation and aggregation in whole blood by flow cytometry. An in-depth analysis conducted on the obtained results as a function of the type of modification indicates small but statistically significant differences in the interaction of platelets with the tested surfaces of metallic biomaterials. [ABSTRACT FROM AUTHOR]

Accessing homogenous glycoconjugates is of significance for assessing their biophysical activities and sometimes as vaccine candidate. Synthesis of glycoconjugates involves two species of which, glycosyl donor plays pivotal role in controlling the outcome of the glycosylation. Recently discovered alkynyl glycosyl carbonate donors possess self‐stability, high reactivity, and fast reaction time (15–30 min) when activated with [Au]/[Ag]‐catalysts. Herein, we report metal free conditions for the activation of the same alkynyl glycosyl carbonate donors using I2/TMSOTf in stoichiometric quantities. Extrusion product was characterized to be the vinylidene iodide by single crystal X‐ray analysis. The reaction conditions were illustrated to be suitable for synthesis of various glycosides, purine/pyrimidine nucleosides and a pentasaccharide repeating unit of Klebsiella pneumoniae (O‐3‐antigen). [ABSTRACT FROM AUTHOR]

It is difficult to separate smithsonite from quartz with metal ion activation through flotation using sodium oleate (NaOL) as the collector. The inevitable Zn2+ in the flotation process of zinc oxide ore makes the separation of smithsonite and quartz more difficult. Thus, this study investigated the use of phytic acid (PA) as a flotation depressant to separate smithsonite from Zn2+-activated quartz while utilizing sodium oleate as the collector. Microflotation tests indicated that phytic acid could selectively inhibit the flotation of Zn2+-activated quartz without affecting the flotation of smithsonite. The measured zeta potentials revealed that the existence of phytic acid hindered sodium oleate adsorption to the surface of Zn2+-activated quartz but had little influence on the adsorption of smithsonite. Zn2+ dissolution tests and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy analysis indicated that the phytic acid could dissolve the Zn2+ from the minerals' surfaces into the solution. In conjunction with X-ray photoelectron spectroscopy results, the analysis indicated that phytic acid could adsorb onto the Zn2+-activated quartz surface and eliminate active sites for sodium oleate adsorption by dissolving the active Zn2+ from the quartz surface into the solution. [ABSTRACT FROM AUTHOR]

Currently, there is a lack of detailed knowledge about methane (CH4) reactions on metal oxide surfaces. This reaction involves in different processes such as chemical looping combustion and catalytic carbon dioxide (CO2) reforming of CH4. In this study, in situ diffuse reflectance infrared Fourier transform spectroscopy was used to investigate CH4 reaction on three transition metal oxides (CoO, CuO, and α-Fe2O3) which are commonly used in these processes at temperatures ranging from 100 °C to 700 °C. The results show that CH4 is adsorbed on the metal oxide surfaces as methoxy and formate, and then the methoxy group reacts with the metal oxide lattice oxygen forming bicarbonate. Under the effect of the used reaction temperature, the bicarbonate decomposes to CO2 and water vapor. [ABSTRACT FROM AUTHOR]

For single‐atom‐layer hydrogen evolution reaction catalysts, enrichment of the 1T‐phase in monolayer molybdenum disulfide is important to achieve ideal metal utilization efficiency and exposure of active surface atoms. Herein, it is discovered that the 1T‐phase degree in monolayer MoS2 can be enhanced through sulfidation of the Pd species deposited on MoS2 (PdxSy/1T‐MoS2). Raman and X‐ray photoelectron spectroscopy reveal that the sulfidation‐assisted phase transition results in considerably greater proportions of 1T‐phase fraction (up to 86%) without using alkali‐metal‐based approaches. Observations of S‐atom displacement/translation at the atomic level contribute to the understanding of the phase transformation of MoS2. The maximized surface atom activation and metal utilization efficiency in PdxSy/1T‐MoS2 lead to unprecedentedly high mass activity (−3444 A mgPd−1) and turnover frequency (1892 s−1), three orders of magnitude higher than those of commercial Pt/C 10 wt% (3.6 A mgPt−1 and 3.6 s−1). The sulfidation‐assisted 1T‐phase enrichment has major implications for the designs of efficient electrocatalysts through MoS2 phase engineering. [ABSTRACT FROM AUTHOR]

High-level ab-initio calculations show neutral tri-coordinate pyramidal boron centers P3B and As3B that can be used to activate H2O and NH3 molecule. The acidic center and the basic center of the pyramidal species are bonded, yet due to the spatial arrangement of the respective orbitals, they are forbidden to interact with each other. This bifunctional property is utilized to carry out the activation process of water and ammonia in a metal-free approach. [ABSTRACT FROM AUTHOR]

Understanding the functional properties of severe acute respiratory syndrome coronavirus 2 nonstructural proteins is essential for defining their roles in the viral life cycle, developing improved therapeutics and diagnostics, and countering future variants. Coronavirus nonstructural protein Nsp15 is a hexameric U-specific endonuclease whose functions, substrate specificity, mechanism, and dynamics are not fully defined. Previous studies report that Nsp15 requires Mn2+ ions for optimal activity; however, the effects of divalent ions on Nsp15 reaction kinetics have not been investigated in detail. Here, we analyzed the single- and multiple-turnover kinetics for model ssRNA substrates. Our data confirm that divalent ions are dispensable for catalysis and show that Mn2+ activates Nsp15 cleavage of two different ssRNA oligonucleotide substrates but not a dinucleotide. Biphasic kinetics of ssRNA substrates demonstrates that Mn2+ stabilizes alternative enzyme states that have faster substrate cleavage on the enzyme. However, we did not detect Mn2+-induced conformational changes using CD and fluorescence spectroscopy. The pH-rate profiles in the presence and absence of Mn2+ reveal active-site ionizable groups with similar pKas of ca. 4.8 to 5.2. An Rp stereoisomer phosphorothioate modification at the scissile phosphate had minimal effect on catalysis supporting a mechanism involving an anionic transition state. However, the Sp stereoisomer is inactive because of weak binding, consistent with models that position the nonbridging phosphoryl oxygen deep in the active site. Together, these data demonstrate that Nsp15 employs a conventional acid-base catalytic mechanism passing through an anionic transition state, and that divalent ion activation is substrate dependent. [ABSTRACT FROM AUTHOR]

Birch reduction has been widely used in organic synthesis for over half a century as a powerful method to dearomatize arenes into 1,4‐cyclohexadiene derivatives. However, the conventional Birch reduction reaction using liquid ammonia requires laborious procedures to ensure inert conditions and low temperatures. Although several ammonia‐free modifications have been reported, the development of an operationally simple, efficient, and scalable protocol remains a challenge. Herein, we report an ammonia‐free lithium‐based Birch reduction in air without special operating conditions using a ball‐milling technique. This method is characterized by its operational simplicity and an extremely short reaction time (within 1 min), probably owing to the in situ mechanical activation of lithium metal, broad substrate scope, and no requirement for dry bulk solvents. The potential of our flash Birch reaction is also demonstrated by the efficient reduction of bioactive target molecules and gram‐scale synthesis. [ABSTRACT FROM AUTHOR]

Activation of metal oxides by light is a robust yet facile approach to manipulating their surface chemistry for favorable reactions with target molecules in heterogeneous catalysis and gas sensors. However, a limited understanding of interface chemistry and the involved mechanism impedes the development of a rational design of oxide interfaces for light‐activated gas sensing. Herein, the TiOx‐assisted photosensitization of In2O3 toward NO2 sensing is investigated as a case study to elucidate the detailed mechanism of light‐activated surface chemistry at the metal/gas interface. The resultant heterogeneous oxides exhibit outstanding NO2 sensing performance under light irradiation thanks to abundant photoexcited electrons and holes that serve as adsorption and desorption sites, respectively, to accelerate both surface reactions. Furthermore, the facile transfer of electrons and holes across the TiOx‐In2O3 interface contributes to improving the reversibility of sensing kinetics. Through this study, the mechanistic understanding is established of how the surface chemistry of metal oxide surfaces can be tuned by light activation providing an effective route to the design fabrication of high‐performance gas sensors. [ABSTRACT FROM AUTHOR]

Understanding the main steps involved in the activation of passive metals is an extremely important subject in the mechanical and energy industry and generally in surface science. The titanium-H2SO4 system is particularly useful for this purpose, as the metal can either passivate or corrode depending on potential. Although several studies tried to hypothesise the surface state of the electrode, there is no general consensus about the surface state of Ti in the active–passive transition region. Here by combining in-situ atomic force microscopy (AFM) and Raman spectroscopy, operating in an electrochemical cell, we show that the cathodic electrification of Ti electrodes causes the dissolution of the upper TiO2 portion of the passive film leaving the electrode covered by only a thin layer of titanium monoxide. Fast anodic reactions involved the acidification of the solution and accumulation of sulphur containing anions. This produces a local increase of the solution turbidity, allowing to distinguish favourable regions for the precipitation of TiOSO4·2H2O. These results give a clear answer to the long-stated question of the physical origin behind the formation of negative polarization resistances, sometimes occurring in corroding systems, and a rationale about the proton-induced degradation of passive surfaces in presence of sulphur containing species. [ABSTRACT FROM AUTHOR]

A nanozyme-like colorimetric sensing strategy based on persulfate activation on Co-based metal – organic frameworks is developed for biomolecule detection in solution and on paper strips. By switching from H2O2 activation on nanozymes to catalytic persulfate activation, this general strategy provides higher sensitivity, faster speed, and wider application ranges for detection. [ABSTRACT FROM AUTHOR]

In recent years, as a result of anthropogenic activities, a rise in environmental stresses has been observed. Sessile organisms such as plants make use of signalling in order to interpret and respond appropriately to environmental changes. An evolutionary conserved signal transduction module i.e., mitogen-activated protein kinase (MAPK) is a component of kinase module engaged in different cellular signalling responses in eukaryotes including plants. They receive the extracellular signal and transmitted it to the nucleus for maintenance of cellular homeostasis. The cascade of MAPK is based on 3 components i.e., MAPK kinase kinase (MAPKKK), MAPK kinase (MAPKK), and MAPK; they are connected with each other by phosphorylation mechanism and finally transmit the signals to a particular transcription factor/s (TxFs). In plants, MAPK-based signalling can be regulated by different phytohormones. Not only cell division and differentiation, MAPK signalling plays a crucial role in various biotic and abiotic stress by generating antioxidative mechanism within the cell. Rampant industrialization and subsequent use of various agrochemicals make soil polluted by piling the soil with different kinds of heavy metals which is not essential to human beings as well as for the plants to survive. The present review is based on the signalling mechanism of MAPK cascade of plants in response to heavy metal stress (HMs). [ABSTRACT FROM AUTHOR]

This work presents the experimental results of narrow gap butt welding of steel plates with large thickness by using the Metal Active Gas (MAG) welding method. The typical defects are accompanied with this process such as the infusion in the side wall and the porosity due to the narrow gap which affect on the melting process. Thus, some publications noted the results of welding for the thickness up to 20-30 mm and the chamfer angle about 30° using GMAW/MIG, GTAW/TIG, SMAW and new development such as laser - arc hybrid, laser multi-pass technique, super-TIG welding etc. But the production requires the solution to save the costs by the reduction of time, labour and investment keeping the standard quality. That is the aim of this study. In order to improve the quality of weld joint and increase the productivity of the process, is it suggested to develop the innovative welding process, in which the welding voltage - Uw, the translational velocity of the tip - Vt, and rotational velocity of the tip - Vr, are changing. This helped to increase the thickness of steel plates up to 50 mm and the chamfer angle decreased at 15°, providing the satisfied quality of the weld. The micrography study serve as the preliminary proof of this hypothesis. The microstructures in 4 regions, such as the weld center zone, heat-affected zone (HAZ), parent metal region, and the boundary between the weld metal and the HAZ were examined. The microstructures of 13 positions from different experiments are investigated using the optical microscope (Axiovert 25). These experiments covered all specific points (node) locating accordingly to three layers from bottom to top of the weld joint. The findings proved the welding quality is similar in case of narrow gap but the chamfer angle is twice lower and the thickness is increased. The result of the study enhances the productivity due to saving the labour cost and the welding materials. It is recommended to consider the effect of other factors (such as cooling conditions, dwell time when the arc approaching the side walls) to optimize the weld quality. There is the huge volume of the heavy steel constructions with the thick steel construction and specific narrow gap in industry. The results of this study with the optimization and more deeper evaluation the influence of main parameters of welding process to eliminate the typical defects will be the valuable recommendation for the managers and engineers in the production of metallic constructions. [ABSTRACT FROM AUTHOR]

The electrochemical carbon dioxide reduction reaction (CO2RR), which can produce value‐added chemical feedstocks, is a proton‐coupled‐electron process with sluggish kinetics. Thus, highly efficient, cheap catalysts are urgently required. Transition metal oxides such as CoOx, FeOx, and NiOx are low‐cost, low toxicity, and abundant materials for a wide range of electrochemical reactions, but are almost inert for CO2RR. Here, we report for the first time that nitrogen doped carbon nanotubes (N‐CNT) have a surprising activation effect on the activity and selectivity of transition metal‐oxide (MOx where M = Fe, Ni, and Co) nanoclusters for CO2RR. MOx supported on N‐CNT, MOx/N‐CNT, achieves a CO yield of 2.6–2.8 mmol cm−2 min−1 at an overpotential of −0.55 V, which is two orders of magnitude higher than MOx supported on acid treated CNTs (MOx/O‐CNT) and four times higher than pristine N‐CNT. The faraday efficiency for electrochemical CO2‐to‐CO conversion is as high as 90.3% at overpotential of 0.44 V. Both in‐situ XAS measurements and DFT calculations disclose that MOx nanoclusters can be hydrated in CO2 saturated KHCO3, and the N defects of N‐CNT effectively stabilize these metal hydroxyl species under carbon dioxide reduction reaction conditions, which can split the water molecules and provide local protons to inhibit the poisoning of active sites under carbon dioxide reduction reaction conditions. [ABSTRACT FROM AUTHOR]

A number of Pt-Re gasoline reforming catalysts have been synthesized, differing from each other in chemical composition and preparation method. The synthesized catalysts exhibit fairly high activity under the studied conditions (T = 480-500 °C, V = 2.0 h-1, P = 8 atm and H2/feed = 5.5). [ABSTRACT FROM AUTHOR]