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Bacterial spores are highly resilient and capable of surviving extreme conditions, making them a persistent threat in contexts such as disease transmission, food safety, and bioterrorism. Their ability to withstand conventional sterilization methods necessitates rapid and accurate detection techniques to effectively mitigate the risks they present. In this study, we introduce a surface-enhanced Raman spectroscopy (SERS) approach for detecting Bacillus thuringiensis spores by targeting calcium dipicolinate acid (CaDPA), a biomarker uniquely associated with bacterial spores. Our method uses probe sonication to disrupt spores, releasing their CaDPA, which is then detected by SERS on drop-dried supernatant mixed with gold nanorods. This simple approach enables the selective detection of CaDPA, distinguishing it from other spore components and background noise. We demonstrate detection of biogenic CaDPA from concentrations as low as 10³ spores/mL, with sensitivity reaching beyond CaDPA levels of a single spore. Finally, we show the method’s robustness by detecting CaDPA from a realistic sample of fresh milk mixed with spores. These findings highlight the potential of SERS as a sensitive and specific technique for bacterial spore detection, with implications for fields requiring rapid and reliable spore identification.

Solar collectors have the potential for significant climate change mitigation by substituting heat produced with fossil fuels. To achieve this, collectors with highly efficient solar absorbers are essential. Carbon nanotubes are highly absorbing, sustainable, cheap, and thermally stable, making them a promising material for solar absorbers. However, achieving a high solar absorptance and low thermal emittance (solar selectivity), while maintaining good thermal stability and scalability is challenging. Here, we present a selective coating based on multi-walled carbon nanotubes and silica (SiO₂). A water-based dispersion enabled by carboxyl functionalization of the carbon nanotubes (CNT_F) is spray coated on a stainless steel (SS) substrate and fixated with sol-gel dip coated silica. The SS/CNT_F/SiO₂ surface exhibits an optical selectivity dependent on CNTF area load and with 0.83 gCNT m⁻² a solar absorptance and thermal emittance of 0.94 and 0.40, respectively, is achieved. The coating also demonstrates excellent thermal stability, with an estimated lifetime of >25 years at working temperatures ≤222°C. All together, we show that by using scalable and cheap technology, concurrent with sustainable materials and a simple structural design, we can manufacture a coating that exhibits properties suitable for low-to-mid-temperature applications. Our study highlights the potential of carbon-based solar absorbers.

The water oxidation half-reaction is vital in numerous alternative-energy blueprints and technologies since it can provide four protons and four electrons necessary for transforming renewable energy into chemicals and fuels. Significant progress has been made in recent decades in regard to the development of heterogeneous and homogeneous water oxidation catalysts (WOCs). However, homogeneous and heterogeneous catalysts are two parallel frontiers in catalysis science, each possessing their individual advantages and disadvantages. It is urgently required to construct desirable catalysts combining the merits and overcoming the natural shortcomings of homogeneous and heterogeneous WOCs. This Perspective demonstrates an overview of recent progress in utilizing insoluble polyoxometalate (POM) clusters as a promising bridge between homogeneous and heterogeneous WOCs and discusses the characterization methods for the stability, the origin of enhanced activities, electron transfer dynamics, and structure-property correlation of insoluble POM cluster WOCs. This Perspective not only guides the design of robust and efficient insoluble POM cluster catalysts applied for energy transformation but also provides important insights into the design of POM-based heterogeneous catalysts applied in other important fields.

The insulation in the stator of a low voltage electric motor has a double purpose: ensuring the electric insulation around the stator wiring as well as permitting a good evacuation of the generated heat. Improving the heat transfer properties of the slot liner within the stator while maintaining its electrical insulation properties allows for more efficient electric motors. This paper presents different types of composites based on an aramid matrix with boron nitride, zinc oxide and aluminum oxide fillers. The effect of the different filler materials on the thermal conductivity and the electric insulation properties of the slot liner are presented. Perspectives on the needs for a life cycle assessment of the slot liner constituents are evoked.

Introduction: Polymethyl methacrylate is a polymer commonly used in clinicaldentistry, including denture bases, occlusal splints and orthodontic retainers.

Methods: To augment the polymethyl methacrylate-based dental appliances incounteracting dental caries, we designed a polymer blend film composed ofpolymethyl methacrylate and polyethylene oxide by solution casting and addedsodium fluoride.

Results: Polyethylene oxide facilitated the dispersion of sodium fluoride,decreased the surface average roughness, and positively influenced thehydrophilicity of the films. The blend film made of polymethyl methacrylate,polyethylene oxide and NaF with a mass ratio of 10: 1: 0.3 showed sustainedrelease of fluoride ions and acceptable cytotoxicity. Antibacterial activity of all thefilms to Streptococcus mutans was negligible.

Discussion: This study demonstrated that the polymer blends of polyethyleneoxide and polymethyl methacrylate could realize the relatively steady release offluoride ions with high biocompatibility. This strategy has promising potential toendow dental appliances with anti-cariogenicity.

MoS₂ is widely praised as a promising replacement for Pt as an electrocatalyst for the hydrogen evolution reaction (HER), but even today, it still suffers from low performance. This issue is tackled by using Mn³⁺ as a surface modifier to trigger sulfur vacancy formation and enhance electron transport in few-layered 2H MoS₂. Only 10% of Mn is sufficient to transform the semiconductive MoS₂ into an active HER electrocatalyst. The insertion of Mn reduces both HER onset potential and Tafel slope which allows reaching 100 mA/cm² at an overpotential of 206 mV, ten times larger of what undoped MoS₂ can achieve. The enhanced activity arises because Mn³⁺ introduces electronic states near the conduction band, promotes sulfur vacancies, and increases the hydrogen adsorption. In addition to its facile production and extended shelf-life, Mn–MoS₂ exhibits an efficiency of 73% at 800 mA/cm² and 2.0 V when used in proton exchange membrane water electrolyzers.

The interaction between metal and support is critical in oxygen catalysis as it governs the charge transfer between these two entities, influences the electronic structures of the supported metal, affects the adsorption energies of reaction intermediates, and ultimately impacts the catalytic performance. In this study, we discovered a unique charge transfer reversal phenomenon in a metal/carbon nanohybrid system. Specifically, electrons were transferred from the metal-based species to N-doped carbon, while the carbon support reciprocally donated electrons to the metal domain upon the introduction of nickel. This led to the exceptional electrocatalytic performances of the resulting Ni-Fe/Mo2C@nitrogen-doped carbon catalyst, with a half-wave potential of 0.91 V towards oxygen reduction reaction (ORR) and a low overpotential of 290 mV at 10 mA cm−2 towards oxygen evolution reaction (OER) under alkaline conditions. Additionally, the Fe-Ni/Mo2C@carbon heterojunction catalyst demonstrated high specific capacity (794 mA h gZn−1) and excellent cycling stability (200 h) in a Zn-air battery. Theoretical calculations revealed that Mo2C effectively inhibited charge transfer from Fe to the support, while secondary doping of Ni induced a charge transfer reversal, resulting in electron accumulation in the Fe-Ni alloy region. This local electronic structure modulation significantly reduced energy barriers in the oxygen catalysis process, enhancing the catalytic efficiency of both ORR and OER. Consequently, our findings underscore the potential of manipulating charge transfer reversal between the metal and support as a promising strategy for developing highly-active and durable bi-functional oxygen electrodes.

Rational design and synthesis of subnanometric bimetallic clusters (SBCs) within a narrow size distribution, along with achieving full SBCs exposure on supporting materials, are formidable challenges that must be overcome to realize potential applications. This work details a facile strategy to synthesize fully exposed PtW SBCs with an average size of 0.81 nm on the surface of spherical N-doped carbon (PtW/NC), which is underpinned by the electrostatic interactions between the negatively charged [H3PtW6O24]5- polyanions and the positively charged closed-pore metal-organic framework (MOF) [Zn5(OH)2(AmTRZ)6]2+. The PtW/NC exhibits significant electrocatalytic performance and stability for the alkaline hydrogen evolution reaction with an ultralow overpotential of 4 mV at 10 mA cm-2, a low Tafel slope of 29 mV dec-1, and a long-term electrolysis stability exceeding 140 h. The Pt mass activity of PtW/NC is 34 times higher than that of commercial 20 wt % Pt/C at the 100 mV overpotential. Both theoretical calculations and electrochemical measurements indicate that a synergistic effect between Pt and W is responsible for this notable catalytic performance. The synthetic approach outlined in this work can be applied to other MOFs and coordination networks that lack pores or have limited porosity.

Metal-assisted chemical etching (MACE) is a cheap and scalable method that is commonly used to obtain silicon nano- or microwires but lacks spatial control. Herein, we present a synthesis method for producing vertical and highly periodic silicon microwires, using displacement Talbot lithography before wet etching with MACE. The functionalized periodic silicon microwires show 65% higher PEC performance and 2.3 mA/cm2 higher net photocurrent at 0 V compared to functionalized, randomly distributed microwires obtained by conventional MACE at the same potentials.

Electrochemical water splitting powered by renewable energy sources hold potential for clean hydrogen production. However, there is still persistent challenges such as low solar-to-hydrogen conversion efficiency and sluggish oxygen evolution reactions. Here, we address the poor kinetics by studying and strengthening the coupling between Ce and W, and concurrently establishing Ce-W bi-atomic clusters on P,N-doped carbon (WN/WC-CeO_2−x@PNC) with a “treasure-bowl” style. The bifunctional active sites are established using a novel and effective self-sacrificial strategy involving in situ induced defect formation. In addition, by altering the coupling of the W(d)-N(p) and W(d)-Ce(f) orbitals in the WN/WC-CeO_2−x supramolecular clusters, we are able to disrupt the linear relationship between the binding energies of reaction intermediates, a key to obtain high catalytic performance for transition metals. Through the confinement of the WN/WC-CeO_2−x composite hetero-clusters within the sub-nanometre spaces of hollow nano-bowl-shaped carbon reactors, a stable and efficient hydrogen production via water electrolysis could be achieved. When assembled together with a solar GaAs triple junction solar cell, a solar-to-hydrogen conversion efficiency of 18.92% in alkaline media could be realized. We show that the key to establish noble metal free catalysts with high efficiency lies in the fine-tuning of the metal-metal interface, forming regions with near optimal adsorption energies for the reaction intermediates participating in water electrolysis.