Digital microfluidics with integrated Raman sensor for high-sensitivity in-situ bioanalysis.

This study introduces an advanced bioanalytical platform that combines digital microfluidics (DMF) with Raman spectroscopy, effectively addressing common issues in bioanalysis such as sample contamination, excessive consumption of samples and reagents, and manual handling. Our innovative system is engineered to handle diverse sample types and enables both sample preparation and in-situ analysis on a single device, utilizing less than 5 μL of samples and reagents. It incorporates a Translucent Raman Enhancement Stack (TRES) sensor, which boosts the detection signal, and includes droplet-driving functionality for automated processing of complex samples in a compact setting.

Adaptive growth strategies of to drought and nitrogen enrichment: a physiological and biochemical perspective.

Nitrogen deposition and drought significantly influence plant growth and soil physicochemical properties. This study investigates the effects of nitrogen deposition and water stress on the growth and physiological responses of , and how these factors interact to influence the overall productivity. Two-year-old potted seedlings were selected to simulate nitrogen deposition and water stress.

Exogenous protectants alleviate ozone stress in Trifolium repens: Impacts on plant growth and endophytic fungi.

Industrialization-driven surface ozone (O) pollution significantly impairs plant growth. This study evaluates the effectiveness of exogenous protectants [3 mg L⁻ abscisic acid (ABA), 400 mg L⁻ ethylenediurea (EDU), and 80 mg L⁻ spermidine (Spd)] on Trifolium repens subjected to O stress in open-top chambers, focusing on plant growth and dynamics of culturable endophytic fungal communities. Results indicate that O exposure adversely affects photosynthesis, reducing root biomass and altering root structure, which further impacts the ability of plant to absorb essential nutrients such as potassium (K), magnesium (Mg), and zinc (Zn).

What Elements Really Intercalate into Pd Lattice When Heated in Dimethylformamide?

Palladium hydrides (PdH) are pivotal in both fundamental research and practical applications across a wide spectrum. PdH nanocrystals, synthesized by heating in dimethylformamide (DMF), exhibit remarkable stability, granting them widespread applications in the field of electrocatalysis. However, this stability appears inconsistent with their metastable nature.

Comprehensive Understanding of the Kinetic Behaviors of Main Protease from SARS-CoV-2 and SARS-CoV: New Data and Comparison to Published Parameters.

The main protease (M) is a promising drug target for inhibiting the coronavirus due to its conserved properties and lack of homologous genes in humans. However, previous studies on M's kinetic parameters have been confusing, hindering the selection of accurate inhibitors. Therefore, obtaining a clear view of M's kinetic parameters is necessary.

Progress and Perspective for In Situ Studies of Oxygen Reduction Reaction in Proton Exchange Membrane Fuel Cells.

Proton exchange membrane fuel cell (PEMFC) is one of the most promising energy conversion devices with high efficiency and zero emission. However, oxygen reduction reaction (ORR) at the cathode is still the dominant limiting factor for the practical development of PEMFC due to its sluggish kinetics and the vulnerability of ORR catalysts under harsh operating conditions. Thus, the development of high-performance ORR catalysts is essential and requires a better understanding of the underlying ORR mechanism and the failure mechanisms of ORR catalysts with in situ characterization techniques.

Bifunctional Ultrathin RhRu -Alloy Nanowire Electrocatalysts for Hydrazine-Assisted Water Splitting.

Hydrazine-assisted water electrolysis offers a feasible path for low-voltage green hydrogen production. Herein, the design and synthesis of ultrathin RhRu -alloy wavy nanowires as bifunctional electrocatalysts for both the anodic hydrazine oxidation reaction (HzOR) and the cathodic hydrogen evolution reaction (HER) is reported. It is shown that the RhRu -alloy wavy nanowires can achieve complete electrooxidation of hydrazine with a low overpotential and high mass activity, as well as improved performance for the HER.

Deuterium Solvent Kinetic Isotope Effect on Enzymatic Methyl Transfer Catalyzed by Catechol O-methyltransferase.

Introduction: Catechol o-methyltransferase plays a key role in the metabolism of catecholamine neurotransmitters. At present, its catalytic mechanism, overall structure, and kinetic characteristics have been basically clarified, but few people have paid attention to the function of solvents on enzymatic methyl transfer reactions. The influence of solvents on enzymatic reactions has always been a fuzzy hot topic.

Graphene-nanopocket-encaged PtCo nanocatalysts for highly durable fuel cell operation under demanding ultralow-Pt-loading conditions.

The proton exchange membrane fuel cell (PEMFC) as an attractive clean power source can promise a carbon-neutral future, but the widespread adoption of PEMFCs requires a substantial reduction in the usage of the costly platinum group metal (PGM) catalysts. Ultrafine nanocatalysts are essential to provide sufficient catalytic sites at a reduced PGM loading, but are fundamentally less stable and prone to substantial size growth in long-term operations. Here we report the design of a graphene-nanopocket-encaged platinum cobalt (PtCo@Gnp) nanocatalyst with good electrochemical accessibility and exceptional durability under a demanding ultralow PGM loading (0.

Silver nanoparticles boost charge-extraction efficiency in microbial fuel cells.

Microbial fuel cells (MFCs) can directly convert the chemical energy stored in organic matter to electricity and are of considerable interest for power generation and wastewater treatment. However, the current MFCs typically exhibit unsatisfactorily low power densities that are largely limited by the sluggish transmembrane and extracellular electron-transfer processes. Here, we report a rational strategy to boost the charge-extraction efficiency in MFCs substantially by introducing transmembrane and outer-membrane silver nanoparticles.

Chemical vapour deposition of Fe-N-C oxygen reduction catalysts with full utilization of dense Fe-N sites.

Replacing scarce and expensive platinum (Pt) with metal-nitrogen-carbon (M-N-C) catalysts for the oxygen reduction reaction in proton exchange membrane fuel cells has largely been impeded by the low oxygen reduction reaction activity of M-N-C due to low active site density and site utilization. Herein, we overcome these limits by implementing chemical vapour deposition to synthesize Fe-N-C by flowing iron chloride vapour over a Zn-N-C substrate at 750 °C, leading to high-temperature trans-metalation of Zn-N sites into Fe-N sites. Characterization by multiple techniques shows that all Fe-N sites formed via this approach are gas-phase and electrochemically accessible.

Beyond Extended Surfaces: Understanding the Oxygen Reduction Reaction on Nanocatalysts.

Increasing the platinum utilization efficiency is the key to the advancement and broad dissemination of proton-exchange-membrane fuel cells (PEMFCs). Central to the task is the creation of highly active and durable Pt-based catalysts for the cathodic oxygen reduction reaction (ORR), which demands a comprehensive understanding of the ORR processes on these catalysts under reaction conditions. Past efforts have accumulated a vast wealth of knowledge of the ORR on extended Pt and Pt-alloy model surfaces.

A Polymerization-Assisted Grain Growth Strategy for Efficient and Stable Perovskite Solar Cells.

Intrinsically, detrimental defects accumulating at the surface and grain boundaries limit both the performance and stability of perovskite solar cells. Small molecules and bulkier polymers with functional groups are utilized to passivate these ionic defects but usually suffer from volatility and precipitation issues, respectively. Here, starting from the addition of small monomers in the PbI precursor, a polymerization-assisted grain growth strategy is introduced in the sequential deposition method.

Evolution Pathway from Iron Compounds to Fe(II)-N Sites through Gas-Phase Iron during Pyrolysis.

Pyrolysis is indispensable for synthesizing highly active Fe-N-C catalysts for the oxygen reduction reaction (ORR) in acid, but how Fe, N, and C precursors transform to ORR-active sites during pyrolysis remains unclear. This knowledge gap obscures the connections between the input precursors and the output products, clouding the pathway toward Fe-N-C catalyst improvement. Herein, we unravel the evolution pathway of precursors to ORR-active catalyst comprised exclusively of single-atom Fe(II)-N sites via in-temperature X-ray absorption spectroscopy.

Enhanced adsorptive desulfurization by iso-structural amino bearing IRMOF-3 and IRMOF-3@AlOversus MOF-5 and MOF-5@AlO revealing the predominant role of hydrogen bonding.

Desulfurization of oragnosulfur-containing fuels signify a great importance in improving the quality of fuel and is also beneficial to the environment. In this work, we report two new composites, namely, MOF-5@γ-Al2O3 and IRMOF-3@γ-Al2O3, synthesized by loading iso-structural MOF-5 and amino bearing IRMOR-3 onto the γ-Al2O3 beads (the loading amount of MOF-5 and IRMOF-3 are 13.4 wt% and 16.

Ultra-high Areal Capacity Realized in Three-Dimensional Holey Graphene/SnO Composite Anodes.

Nanostructured alloy-type electrode materials and its composites have shown extraordinary promise for lithium-ion batteries (LIBs) with exceptional gravimetric capacity. However, studies to date are usually limited to laboratory cells with too low mass loading (and thus too low areal capacity) to exert significant practical impact. Herein, by impregnating micrometer-sized SnO/graphene composites into 3D holey graphene frameworks (HGF), we show that a well-designed 3D-HGF/SnO composite anode with a high mass loading of 12 mg cm can deliver an ultra-high areal capacity up to 14.

Pt-Based Nanocrystal for Electrocatalytic Oxygen Reduction.

Currently, Pt-based electrocatalysts are adopted in the practical proton exchange membrane fuel cell (PEMFC), which converts the energy stored in hydrogen and oxygen into electrical power. However, the broad implementation of the PEMFC, like replacing the internal combustion engine in the present automobile fleet, sets a requirement for less Pt loading compared to current devices. In principle, the requirement needs the Pt-based catalyst to be more active and stable.

Double-negative-index ceramic aerogels for thermal superinsulation.

Ceramic aerogels are attractive for thermal insulation but plagued by poor mechanical stability and degradation under thermal shock. In this study, we designed and synthesized hyperbolic architectured ceramic aerogels with nanolayered double-pane walls with a negative Poisson's ratio (-0.25) and a negative linear thermal expansion coefficient (-1.

Unifying the Hydrogen Evolution and Oxidation Reactions Kinetics in Base by Identifying the Catalytic Roles of Hydroxyl-Water-Cation Adducts.

Despite the fundamental and practical significance of the hydrogen evolution and oxidation reactions (HER/HOR), their kinetics in base remain unclear. Herein, we show that the alkaline HER/HOR kinetics can be unified by the catalytic roles of the adsorbed hydroxyl (OH)-water-alkali metal cation (AM) adducts, on the basis of the observations that enriching the OH abundance via surface Ni benefits the HER/HOR; increasing the AM concentration only promotes the HER, while varying the identity of AM affects both HER/HOR. The presence of OH-(HO) -AM in the double-layer region facilitates the OH removal into the bulk, forming OH-(HO) -AM as per the hard-soft acid-base theory, thereby selectively promoting the HER.

Nanoscale Structure Design for High-Performance Pt-Based ORR Catalysts.

Proton-exchange-membrane fuel cells (PEMFCs) are of considerable interest for direct chemical-to-electrical energy conversion and may represent an ultimate solution for mobile power supply. However, PEMFCs today are primarily limited by the sluggish kinetics of the cathodic oxygen reduction reaction (ORR), which requires a significant amount of Pt-based catalyst with a substantial contribution to the overall cost. Hence, promoting the activity and stability of the needed catalyst and minimizing the amount of Pt loaded are central to reducing the cost of PEMFCs for commercial deployment.

Tailored Phase Conversion under Conjugated Polymer Enables Thermally Stable Perovskite Solar Cells with Efficiency Exceeding 21.

The precise control of stoichiometric balance and ionic defects on the surface of solution-processed perovskite is critical to the performance and stability of perovskite solar cells (pero-SCs). Here, we introduce a low-cost and stable conjugated donor polymer (PTQ10) as interfacial layer in the planar n-i-p structured pero-SCs. The polymer was applied to the perovskite intermediate phase before the thermal annealing.

Quantum interference mediated vertical molecular tunneling transistors.

Molecular transistors operating in the quantum tunneling regime represent potential electronic building blocks for future integrated circuits. However, due to their complex fabrication processes and poor stability, traditional molecular transistors can only operate stably at cryogenic temperatures. Here, through a combined experimental and theoretical investigation, we demonstrate a new design of vertical molecular tunneling transistors, with stable switching operations up to room temperature, formed from cross-plane graphene/self-assembled monolayer (SAM)/gold heterostructures.

Microwave-Assisted Rapid Synthesis of Graphene-Supported Single Atomic Metals.

Graphene-supported single atomic metals (G-SAMs) have recently attracted considerable research interest for their intriguing catalytic, electronic, and magnetic properties. The development of effective synthetic methodologies toward G-SAMs with monodispersed metal atoms is vital for exploring their fundamental properties and potential applications. A convenient, rapid, and general strategy to synthesize a series of monodispersed atomic transition metals (for example, Co, Ni, Cu) embedded in nitrogen-doped graphene by two-second microwave (MW) heating the mixture of amine-functionalized graphene oxide and metal salts is reported here.

Surface-Engineered PtNi-O Nanostructure with Record-High Performance for Electrocatalytic Hydrogen Evolution Reaction.

Hydrogen holds the potential of replacing nonrenewable fossil fuel. Improving the efficiency of hydrogen evolution reaction (HER) is critical for environmental friendly hydrogen generation through electrochemical or photoelectrochemical water splitting. Here we report the surface-engineered PtNi-O nanoparticles with enriched NiO/PtNi interface on surface.

On-Chip in Situ Monitoring of Competitive Interfacial Anionic Chemisorption as a Descriptor for Oxygen Reduction Kinetics.

The development of future sustainable energy technologies relies critically on our understanding of electrocatalytic reactions occurring at the electrode-electrolyte interfaces, and the identification of key reaction promoters and inhibitors. Here we present a systematic in situ nanoelectronic measurement of anionic surface adsorptions (sulfates, halides, and cyanides) on ultrathin platinum nanowires during active electrochemical processes, probing their competitive adsorption behavior with oxygenated species and correlating them to the electrokinetics of the oxygen reduction reaction (ORR). The competitive anionic adsorption features obtained from our studies provide fundamental insight into the surface poisoning of Pt-catalyzed ORR kinetics by various anionic species.