Fast Reaction Research Articles

Zinc ferrite nanoparticles as electrode material for supercapacitors.

In the realm of sustainable and renewable nanotechnology, supercapacitors have appeared as the dominant solution for energy conversion and storage. Ferrites while being widely explored in magnetic, electronic and microwave devices, are now being explored for applications in energy storage devices due to possibilities of achieving fast and reversible surface Faradic reactions. In this perspective, a simple and inexpensive chemical co-precipitation method was used to synthesize ultra small ZnFe2O4 nanoparticles (NP). The ZnFe2O4 NP as electrode material show gravimetric capacitance of 186.6 Fg-1 at current density of 1 Ag-1 in 1M H2SO4. Furthermore, the ZnFe2O4 NP based electrode show exceptional capacitive retention of 98% over 1000 cycles at a current density of 3 Ag-1. An asymmetric ZnFe2O4 NP//NiO NP device was fabricated, which achieved a power density of 302.3 WKg-1 at current density of 1.5 Ag-1 and energy density of 14.85 WhKg-1. After 1500 cycles, the device demonstrated capacity retention of 99.4% at 1.5 Ag-1 in the long-term stability testing with 100% efficiency. Our study suggests that ZnFe2O4 NP are promising as a material for future energy storage applications.

The polarity effect in virtual and video see-through mixed reality—better proofreading performance and faster optotype identification with positive display polarity

Virtual and mixed reality (VR/MR) are increasingly used in occupational and educational settings, where clear visual content presentation and accurate user reactions are crucial. On conventional monitors, positive polarity (dark content on light background) has been found to enable more accurate and faster text reading and stimulus recognition than negative polarity (light on dark). However, studies on this polarity effect in VR/MR have been limited by the available display technology, such as lower resolutions and transparent optical see-through MR glasses that favour negative polarity. We therefore used a high-resolution video see-through VR/MR headset with a resolution of 39 pixels per degree to test the polarity effect with tasks and stimuli identical to conventional polarity research. We found that, similar to conventional monitors, positive polarity is superior in VR and MR for tasks requiring fast reactions and reading, and that users prefer positive polarity when reading text in MR.

Structural and Optical Characterization of Reaction Intermediates during Fast Chiral Nanoparticle Growth.

As nanoparticle morphologies produced by seeded growth expand in number and complexity, tracking their evolution during growth is increasingly important to achieving a mechanistic understanding. However, fast reactions such as chiral growth, in which morphologies change within seconds, remain challenging to monitor at the relevant time scale. We introduce a method based on fast addition of the reducing agent NaBH4, enabling interruption of gold nanoparticle growth, as well as access to reaction intermediates for morphological and optical investigations. We show that NaBH4 reduces the remaining gold salt precursors into achiral nanoparticles and prevents further evolution of the target particles, resulting in a time series with intervals down to seconds. The method is demonstrated on fast, micelle-directed, chiral growth on single-crystalline or penta-twinned nanorod seeds, showing fine variations in the temporal evolution of chirality depending on crystal habit. These series provide representative snapshots from a chirality continuum, offering a platform for studying optical-structural relationships.

Molecular Evolution of Target Organosulfur Enables High-Performance Aqueous Zinc Batteries.

Organic cathode materials for aqueous zinc-ion batteries (AZIBs) have garnered significant attention due to their environmental friendliness and structurally customizable nature. However, the low voltage, sluggish redox kinetics, and high solubility of most n-type cathode materials hinder their wide deployment. To overcome these challenges, through molecular evolution, we rationally select a cheap industrial material, organodisulfide 2,2'-dithiobis (benzothiazole) (MBTS), as an n-type cathode material for AZIBs. Due to the presence of N-containing benzothiazole rings, the dissociation energy of the sulfur-sulfur (S-S) bond is reduced, substantially enhancing the discharge voltage and improving the reaction kinetics. They regulate the π-conjugated plane to achieve a low solubility and fast charge transfer. Moreover, density functional theory (DFT) calculations elucidate the synergistic effect between adjacent active sites and Zn2+ storage reactions, revealing that the formation of weak coordination bonds between N and Zn atoms (N-Zn-S bond) reduces the solubility of the discharge product. Molecular evolution has led to the fast reaction kinetics of zinc ion storage, thus achieving a high performance under high mass loading. At a current density of 0.05 A g-1, MBTS exhibits an average discharge voltage of 1.02 V, with a mere overpotential of 100 mV, and delivers a high specific capacity of 153.6 mAh g-1. The assembled pouch cell demonstrates an excellent rate capability of 124.4 mAh g-1 at 1 A g-1 and displays a stable cycle life after 200 cycles with 96.8% capacity retention. Remarkably, MBTS maintains high specific capacity and favorable cycle stability under various ultrahigh loadings, up to 18.2 mg cm-2. The findings provide substantial guidance for practical applications of organic electrode materials in AZIBs.

Non-modal linear stability analysis of reactive front A+B→C for infinitely fast chemical reactions

A theoretical analysis of viscous fingering instability for a reactive system A + B → C with an infinitely fast reaction in a porous medium for a rectilinear flow is presented. By contrast to the traditional quasi-steady-state analysis (QSSA), a non-modal analysis (NMA) based on the fundamental matrix formulation is employed to study the reactive displacement, considering reactants and products with mismatched viscosities. This study investigates the transient growth of perturbations by analysing the singular values and singular vectors to address the optimal energy amplification. We illustrate that an increase in the viscosity contrast, | R b − R c | , resulting from a chemical reaction for a given endpoint viscosity contrast R b , leads to a more unstable system. However, there exist some reactions when R c > R b , the onset delays than the equivalent non-reactive case, R c = R b . It suggests that the stability of the flow is primarily influenced when instability develops downstream within the flow. Furthermore, R b is found to significantly affect the spatio-temporal evolution of perturbations and the underlying physical mechanism. It is demonstrated that the QSSA is inadequate to address the transient growth, and NMA is the most suitable approach to studying the underlying physical mechanism of instability. Furthermore, NMA results align more consistently with non-linear simulations compared with QSSA.

Microsaccade behavior associated with inhibitory control in athletes in the antisaccade task.

The ability to achieve a state of readiness before upcoming tasks, known as a preparatory set, is critical for athletic performance. Here, we investigated these preparatory processes associated with inhibitory control using the anti-saccade paradigm, in which participants are instructed, prior to target appearance, either to automatically look at the target (pro-saccade) or to suppress this automatic response and intentionally look in the opposite direction (anti-saccade). We focused on microsaccadic eye movements that happen before the response saccade in either pro- or anti-saccade tasks, as these microsaccades reflect ongoing preparatory processes during saccade planning before execution. We hypothesized that athletes, compared to non-athletes, would demonstrate better preparation, given research generally indicating higher inhibitory control in athletes. Our findings showed that microsaccade rates decreased before target appearance, with lower rates observed during anti-saccade preparation compared to pro-saccade preparation. However, microsaccade rates and metrics did not differ significantly between athletes and non-athletes. Moreover, reduced microsaccade rates were associated with improved task performance in non-athletes, leading to higher accuracy and faster saccade reaction times (SRTs) in trials without microsaccades. For athletes, only SRTs were affected by microsaccade occurrence. Moreover, the modulation of microsaccadic inhibition on accuracy was more pronounced in non-athletes compared to athletes, though this effect was only marginally significant. In conclusion, while microsaccade responses were modulated by task preparation, differences between athletes and non-athletes were non-significant. These findings, for the first time, highlight the potential of using microsaccades as an online objective index to study preparatory sets in sports science research.

Iron-cobalt-nickel medium-entropy alloy promotes fast polysulfide conversion reaction kinetics for advanced lithium sulfur batteries

Iron-cobalt-nickel medium-entropy alloy promotes fast polysulfide conversion reaction kinetics for advanced lithium sulfur batteries

Green catalysts AuNPs/CQDs from turmeric starch: an effective solution in 4-Nitrophenol reduction

Abstract This paper presents a green synthesis method for growing carbon quantum dots (CQDs) from turmeric starch. The CQDs were then used as reducing agents and stabilizers to synthesize dual-shaped gold nanoparticles (AuNPs) with spherical and triangular shapes. In addition to the advantages of CQDs in catalysis, such as large surface area, many functional groups, and excellent electron transfer ability, the obtained AuNPs/CQDs nanocomposite material benefits from the plasmonic properties of AuNPs, which enhance the light absorption ability and accelerate the catalytic reactions. This material has been applied to effectively catalyze toxic 4-nitrophenol (4-NP) in aqueous media with high efficiency. The synergy between the plasmonic effect of AuNPs and the catalytic properties of CQDs results in a high catalytic efficiency and a fast reaction time of 20 min, making this method simple, rapid, scalable, and highly effective for environmental pollution remediation.

Chemical- and photo-activation of protein-protein thiol-ene coupling for protein profiling

The thiol-ene reaction between an alkene and a thiol can be exploited for selective labelling of cysteine residues in protein profiling applications. Here, we explore thiol-ene activation in systems from chemical models to complex cellular milieus, using UV, visible wavelength and redox initiators. Initial studies in chemical models required an oxygen-free environment for efficient coupling and showed very poor activation when using a redox initiator. When thiol-ene activation was performed in protein and cell lysate models, all three initiation methods were successful. Faster thiol-ene reaction was observed as the cysteine and alkene were brought into proximity by a binding event prior to activation, leading to quicker adduct formation in the protein model system than the chemical models. Furthermore, in the protein-protein coupling, none of the activators required an oxygen-free environment. Taken together, these observations demonstrate the broad potential for thiol-ene coupling to be used in protein profiling.

P-773. Mycobacterium Tuberculosis Liver Abscess in Kidney Transplant Recipients

Abstract Background Recipients of solid organ transplant (SOT) have higher risk for infections, and the prevalence of mycobacterium tuberculosis liver abscess (MTB-LA) without pulmonary/disseminated MTB is 0.34%. However, there is little research on MTB-LA in SOT recipients. Mycobacterium tuberculosis Liver Abscess Cases Upon extensive literature review, this chart details all published, English-language cases of mycobacterium tuberculosis liver abscess in solid organ transplant recipients. Methods We conducted an extensive literature review of MTB-LA in adult SOT recipients. Results Our review showed 4 cases of MTB-LA in SOT recipients (table below). We detail 1 additional case. A 58-year-old male with ESRD due to type 2 diabetes mellitus, and latent MTB underwent kidney transplantation in March 2023. He completed a 6-month course of isoniazid and vitamin B6 for latent MTB 1 month before transplant. His post-operative course was uncomplicated; he was discharged to follow up with his nephrologist. He later developed norovirus illness with fever, which was conservatively managed. He developed new fevers 3 months post-transplant and CT of the abdomen/pelvis revealed a liver abscess, which was treated with empiric broad spectrum antibiotics, and was not amenable to aspiration. At his 4-month post-transplantation, he complained of fatigue, night sweats, poor appetite, and weight loss requiring hospitalization, wherein an MRI of the abdomen/pelvis identified a 3.6 x 3.2 x 6.2 cm liver abscess. The liver abscess aspirate was positive on acid fast bacilli smear and MTB polymerase chain reaction. He was initiated on antituberculosis therapy with isoniazid, rifabutin, pyrazinamide, and ethambutol. Susceptibilities identified pyrazinamide resistance, and led to substitution with levofloxacin. Labs, imaging and microbiology testing were negative for evidence of pulmonary/disseminated MTB. His donor’s information was reviewed; no obvious risk factors for active MTB were found. The recipient of the mate kidney is doing well without evidence of MTB infection. After 2 months of 4-drug antituberculosis therapy, ethambutol was discontinued. CT scan of the abdomen and pelvis at 4 months post anti-tuberculosus therapy revealed a 3 cm area of residual inflammation at the site of prior MTB-LA, in the setting of resolution of prior symptoms. Conclusion Early imaging and diagnostic aspiration of liver abscess with specific stains, culture and PCR testing can facilitate rapid diagnosis and initiation of antituberculosis therapy. Disclosures All Authors: No reported disclosures

Technical Proficiency Analysis in Table Tennis: A Comparative Study Between Advanced and Intermediate Players

The purpose of the study. This study presents a comprehensive examination of technical proficiencies in table tennis, comparing advanced and intermediate players to identify key differentiating factors in performance. Materials and methods. The research involved 40 participants (20 advanced players with 5+ years of competitive experience and 20 intermediate players with 2-4 years of experience) aged 18-25 years. Over a three-month period, participants underwent systematic evaluation of their technical skills, including basic stroke accuracy, biomechanical efficiency, and tactical adaptability. This empirical investigation was undertaken at seven Table Tennis clubs located within the confines of Medan city, Indonesia. Results. Results revealed significant differences between skill levels in most measured parameters: advanced players demonstrated superior forehand drive accuracy (85.3% vs 67.1%, p<0.001), backhand drive accuracy (82.7% vs 63.4%, p<0.001), and rally consistency (28.4 vs 15.6 hits, p<0.001). Biomechanical analysis showed advanced players maintained more optimal arm angles (110.5° vs 95.8°) and faster bat swing speeds (17.8 m/s vs 12.4 m/s). Additionally, advanced players exhibited better tactical adaptation, with more service variations (6.8 vs 4.2 types) and faster reaction times (245ms vs 312ms). Conclusions. The findings highlight that the progression from intermediate to advanced level requires improvements across multiple domains, including technical consistency, biomechanical efficiency, and tactical adaptability. This research provides valuable insights for developing targeted training programs and understanding the multifaceted nature of expertise in table tennis.

A ratiometric fluorescent probe for sensitively tracking peroxynitrite during drug-induced hepatotoxicity.

As one of the essential components of reactive oxygen species (ROS), peroxynitrite (ONOO-) plays an indispensable role in redox homeostasis and signal transduction processes, and its deviant levels are associated with numerous clinical diseases. Therefore, accurate and rapid detection of intracellular ONOO- levels is crucial for revealing its role in physiological and pathological processes. Herein, we constructed a ratiometric fluorescent probe to detect ONOO- levels in biological systems. The probe represents fast reaction rate (within 15 min), outstanding selectivity, good sensitivity (LOD = 13.32 nM) and stability to ONOO-, and it was successfully used for visualizing endogenous ONOO- in living cells. More importantly, it has also been used for tracking the changes of intracellular ONOO- during drug-induced hepatotoxicity with ratiometric fluorescence.

Reaction of Mono‐ and Bidentate Phosphane Oxides with TiCl4 and Ti(NMe2)4

The addition of secondary Mes2P(O)H and of bulky tertiary phosphindole oxide onto TiCl4 leads to formation of trans‐[TiCl4(OPR3)2] 1 and 2. Contrary to this finding, Ti(NMe2)4 metalates secondary dimesitylphosphane oxide and mixtures of the mononuclear complexes [Ti(NMe2)4−n(OPMes2)n] form. The ratio between the amido and phosphinito ligands varies with the stoichiometry; however, pure compounds are not accessible. Fast ligand exchange reactions interconvert these complexes and only mixtures are obtained. The reaction of TiCl4 with bidentate alkane‐α,ω‐diyl‐bis(diarylphosphane oxides), Ar2P(O)–(CH2)n–P(O)Ar2 with Ar/n = Ph/1 (I), Ph/2 (II), and Mes/2 (III)) yields insoluble [(I)2Ti2Cl4(μ‐Cl)2] [Ti2Cl9]2 (3), [(II)2TiCl2] [Ti2Cl9]2 (4), and [(III)2(TiCl3)2] [Ti2Cl9]2 (5) regardless of the applied stoichiometry. All these complexes have the dinuclear [Cl3Ti(μ‐Cl)3TiCl3]− anion in common.

Critical review on development of methylene blue degradation by wet catalytic methods

Abstract The development of textile, agriculture, and other related industries has increased the risk of excessive methylene blue (MB) emissions, making efficient treatment of MB an urgent issue in terms of the economy and environment. The most commonly used chemical treatment methods were wet catalytic methods, including catalytic wet air oxidation (CWAO), catalytic wet peroxide oxidation (CWPO), and photocatalysis. CWAO and CWPO both show fast reaction rates and are environmentally friendly. CWAO uses air as an oxidant at a relatively low cost and can effectively solve the leaching problem of the catalyst. CWPO employs inorganic peroxides like hydrogen peroxide (H2O2) as oxidants to form radicals, showing high efficiency. Photocatalytic degradation utilizes light energy to transform pollutants into harmless molecules with fast kinetic. The selection and application of different methods are analyzed basing on the balance among cost, scale, and efficiency. Finally, the perspective of the effective removal of MB is summarized, containing multiple method combinations, catalyst synthesis optimization, and practical application with less side reaction and instrument loss. More promising technology should be considered in the future for better degradation of MB in the industrial field.

Hierarchical MoS2@NiFeCo-Mo(doped)-Layered Double Hydroxide Heterostructures as Efficient Alkaline Water Splitting (Photo)Electro-catalysts.

Designing cost-effective electrocatalysts with fast reaction kinetics and high stability is an outstanding challenge in green hydrogen generation through overall water splitting (OWS). Layered double hydroxide (LDH) heterostructure materials are promising candidates to catalyze both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), the two OWS half-cell reactions. This work develops a facile hydrothermal route to synthesiz hierarchical heterostructure MoS2@NiFeCo-LDH and MoS2@NiFeCo-Mo(doped)-LDH electrocatalysts, which exhibit extremely good OER and HER performance as witnessed by their low IR-corrected overpotentials of 156 and 61 mV with at a current density of 10mA cm-2 under light assistance. The MoS2@NiFeCo-Mo(doped)-LDH-MoS2@NiFeCo-LDH OWS cell achieves a low cell voltage of 1.46V at 10mA cm-2 during light-assisted water electrolysis. Both materials exhibited exceptional stability under industrially relevant HER and OER conditions, maintaining a current density of 1A cm-2 with minimal alterations in their potential and performance. The experimental and computational results demonstrate that doping the LDH matrix with high-valence Mo atoms and MoS2 quantum dots improves the electrocatalytic activity by 1) enhancing electron transfer, 2) making the electrocatalyst metallic, 3) increasing the number of active sites, 4) lowering the thermodynamic overpotential, and 5) changing the OER mechanism. Overall, this work develops a facile synthesis method to design highly active and stable MoS2@NiFeCo-Mo(doped)-LDH heterostructureelectrocatalysts.

Unveiling the role of mixing in [Fe(CN)6]4− defects and Na content for preparing NaxMn[Fe(CN)6]y · nH2O via microreactor

AbstractTaking advantage of strong mixing performance in oscillating feedback microreactor (OFM), the manganese hexacyanoferrates (NaxMn[Fe(CN)6]y · nH2O, MnHCFs) with low defects and high sodium content were controllably prepared. First, fluid mixing performance in OFM was investigated via dye‐tracer and Villermaux‐Dushman experiments, and the fluid mixing mechanism in OFM was investigated through CFD simulations. Then, MnHCFs were prepared using OFM at different flow rates, and the role of mixing in [Fe(CN)6]4− vacancies and sodium content during co‐precipitation synthesis of MnHCFs was discussed. The results indicate that an increase in flow rates can increase fluid chaos strength, enhancing the mass transfer process to match the extremely fast reaction rate of MnHCFs, thus preparing MnHCFs with high sodium content and low defects. Relevant electrochemical tests indicate that the MnHCF prepared at the largest throughput (180 mL/min) has the highest initial specific capacity (132 mAh/g at 15 mA/g), minimum electrochemical impedance, and fastest sodium ion transport rate.

Aging effects on control ability: an ERP study using the AX continuous performance task in middle-aged and older adults

Abstract The dual mechanisms of control model (DMC model) assumes that aging leads to decline in proactive control and reactive control abilities in various aspects of daily life. However, the methods adopted by previous ERP studies limit their capacity to provide in-depth information on the aging effects of neural processes, such as N2 (reactive control), P3b, and CNV (proactive control). This study aims to clarify the aging effects on proactive control and reactive control by controlling additional (potentially confounding) variables (e.g., physical fitness level) and utilizing N2, CNV, and P3b to specify neural processes in the DMC model. To achieve this goal, a total of sixty-two middle-aged and fifty-nine older adults were recruited. Participants underwent the Senior Fitness Test to measure physical fitness level. Furthermore, participants were required to perform the AX-CPT task while ERPs were recorded. The results were primarily focused on the analysis of N2 in AY trials and the analysis of P3b and CNV in BX trials. Notably, older adults exhibited faster reaction times (RT) than middle-aged adults in AY trials. Conversely, in BX trials, older adults displayed slower RT compared with middle-aged adults. Furthermore, our findings indicated that older adults had higher CNV amplitude at the parietal region in comparison with middle-aged adults in BX trials. We suggest that older adults may tend to engage more attentional resources in avoiding the false alarm in AY trials. In contrast, middle-aged adults may engage in a predictive function that directs attention to a particular response in BX trials.

Revealing the reaction path of UVC bond rupture in cyclic disulfides with ultrafast x-ray scattering.

Disulfide bonds are ubiquitous molecular motifs that influence the tertiary structure and biological functions of many proteins. Yet, it is well known that the disulfide bond is photolabile when exposed to ultraviolet C (UVC) radiation. The deep-UV-induced S─S bond fragmentation kinetics on very fast timescales are especially pivotal to fully understand the photostability and photodamage repair mechanisms in proteins. In 1,2-dithiane, the smallest saturated cyclic molecule that mimics biologically active species with S─S bonds, we investigate the photochemistry upon 200-nm excitation by femtosecond time-resolved x-ray scattering in the gas phase using an x-ray free electron laser. In the femtosecond time domain, we find a very fast reaction that generates molecular fragments with one and two sulfur atoms. On picosecond and nanosecond timescales, a complex network of reactions unfolds that, ultimately, completes the sulfur dissociation from the parent molecule.

Intermediates of Hydrogen Peroxide-Assisted Photooxidation of Salicylic Acid: Their Degradation Rates and Ecotoxicological Assessment.

Accelerated photooxidation of salicylic acid (SA) was performed using UV radiation and hydrogen peroxide. HPLC-MS analysis showed that the primary intermediates are 2,5-dihydroxybenzoic acid, 2,3-dihydroxybenzoic acid, pyrocatechol, and phenol. Deeper oxidation leads to low molecular weight aliphatic acids, such as maleic, fumaric, and glyoxylic. The photooxidation of the main intermediates was carried out in the same conditions. The degradation of SA and its main intermediates follows first-order reaction kinetics. In the case of UV irradiation alone, photodegradation of 2,5-dihydroxybenzoic acid is slightly faster (reaction rate constant is 0.007 min-1) compared to SA (0.0052 min-1). Other products degrade more slowly than SA. Hydrogen peroxide, in concentrations of 1.8-8.8 mM, accelerates the photodegradation of salicylic acid and intermediate products. An ecotoxicological evaluation of SA and the main products was performed using the EPI SuiteTM software. The overall persistence (POV) and long-range transport potential (LRTP) of all transformation products were assessed using OECD POV and the LRTP screening tool. Salicylic acid and its transformation products have low toxicity. Due to their high solubility, these contaminants can travel considerable distances in the aquatic environment. SA and phenol have LRTP values of 156-190 km. Other products can travel shorter distances (less than 100 km).

All-solid-state Li-S batteries with fast solid-solid sulfur reaction.

With promises for high specific energy, high safety and low cost, the all-solid-state lithium-sulfur battery (ASSLSB) is ideal for next-generation energy storage1-5. However, the poor rate performance and short cycle life caused by the sluggish solid-solid sulfur redox reaction (SSSRR) at the three-phase boundaries remain to be solved. Here we demonstrate a fast SSSRR enabled by lithium thioborophosphate iodide (LBPSI) glass-phase solid electrolytes (GSEs). On the basis of the reversible redox between I- and I2/I3-, the solid electrolyte (SE)-as well as serving as a superionic conductor-functions as a surficial redox mediator that facilitates the sluggish reactions at the solid-solid two-phase boundaries, thereby substantially increasing the density of active sites. Through this mechanism, the ASSLSB exhibits ultrafast charging capability, showing a high specific capacity of 1,497 mAh g-1sulfur on charging at 2C (30 °C), while still maintaining 784 mAh g-1sulfur at 20C. Notably, a specific capacity of 432 mAh g-1sulfur is achieved on charging at an extreme rate of 150C at 60 °C. Furthermore, the cell demonstrates superior cycling stability over 25,000 cycles with 80.2% capacity retention at 5C (25 °C). We expect that our work on redox-mediated SSSRR will pave the way for developing advanced ASSLSBs that are high energy and safe.