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Gaskets and seals are essential components in the operation of proton exchange membrane (PEM) fuel cells and are required for keeping hydrogen and air/oxygen within their individual compartments. The durability of these gaskets and seals is necessary, as it influences not only the lifespan but also the electrochemical efficiency of the PEM fuel cell. In this study, the cause of silicon leaching from silicone gaskets under simulated fuel cell conditions was investigated. Additionally, to reduce silicon leaching, the silica surface was treated with methyltrimethoxysilane, vinyltriethoxysilane, and (3,3,3-trifluoropropyl)trimethoxysilane. Changes in the silica surface chemistry were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, thermogravimetric analysis, elemental analysis, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. Inductively coupled plasma-optical emission spectroscopy analysis revealed that surface-treated silica was highly effective in reducing silicon leaching. [ABSTRACT FROM AUTHOR]

The increasing energy demands of the global community can be met with solar energy. Solution-processed organic solar cells have seen great progress in power conversion efficiencies (PCEs). Semitransparent organic solar cells (ST-OSCs) have made enormous progress in recent years and have been considered one of the most promising solar cell technologies for applications in building-integrated windows, agricultural greenhouses, and wearable energy resources. Therefore, through the synergistic efforts of transparent electrodes, engineering in near-infrared photoabsorbent materials, and device engineering, high-performance ST-OSCs have developed, and PCE and average visible transmittance reach over 10% and 40%, respectively. In this review, we present the recent progress in photoabsorbent material engineering and strategies for enhancing the performance of ST-OSCs to help researchers gain a better understanding of structure–property–performance relationships. To conclude, new design concepts in material engineering and outlook are proposed to facilitate the further development of high-performance ST-OSCs. [ABSTRACT FROM AUTHOR]

The strong spin–orbit coupling (SOC) in lead halide perovskites, when inversion symmetry is lifted, has provided opportunities for investigating the Rashba effect in these systems. Moreover, the strong orbital moment, which, in turn, impacts the spin-pair in singlet and triplet electronic states, plays a significant role in enhancing the optoelectronic properties in the presence of external magnetic fields in lead halide perovskites. Here, we investigate the effect of weak magnetic fields (<1 T) on the photoluminescence (PL) properties of CsPbBr 3 nanocrystals with and without Ruddlesden–Popper (RP) faults and single crystals of CH 3 NH 3 PbBr 3. Along with an enhancement in the PL intensity as a function of an external magnetic field, which is observed in both lead bromide perovskites, the PL emission red-shifts in CsPbBr 3 nanocrystals. Density-functional theory calculations of the electronic band-edge in CsPbBr 3 show almost no change in the energy gap as a function of the external magnetic field. The experimental results, thus, suggest the role of mixing of the triplet and singlet excitonic states under weak magnetic fields. This is further deduced from an enhancement in PL lifetimes as a function of the field in CsPbBr 3. In CH 3 NH 3 PbBr 3 , an increase in PL intensity is observed under weak magnetic fields; however, no changes in the peak energy or PL lifetimes are observed. The internal magnetic fields due to SOC are characterized for all three samples and found to be the highest for CsPbBr 3 nanocrystals with RP faults. [ABSTRACT FROM AUTHOR]

Interindividual immune variability is driven predominantly by environmental factors, including exposure to chronic infectious agents such as cytomegalovirus (CMV). We investigated the effects of rhesus CMV (RhCMV) on composition and function of the immune system in young macaques. Within months of infection, RhCMV was associated with impressive changes in antigen presenting cells, T cells, and NK cells--and marked expansion of innate-memory [CD8.sup.+] T cells. These cells express high levels of NKG2A/C and the IL-2 and IL-15 receptor beta chain, CD122. IL-15 was sufficient to drive differentiation of the cells in vitro and in vivo. Expanded NKG2A/[C.sup.+]CD[122.sup.+]CD[8.sup.+] T cells in RhCMV-infected macaques, but not their NKG2-negative counterparts, were endowed with cytotoxicity against class I-deficient K562 targets and prompt IFN- [gamma] production in response to stimulation with IL-12 and IL-18. Because RhCMV clone 68-1 forms the viral backbone of RhCMV-vectored SIV vaccines, we also investigated immune changes following administration of RhCMV 68-1-vectored SIV vaccines. These vaccines led to impressive expansion of NKG2A/[C.sup.+]CD[8.sup.+] T cells with capacity to inhibit SIV replication ex vivo. Thus, CMV infection and CMV-vectored vaccination drive expansion of functional innate-like CD8 cells via host IL-15 production, suggesting that innate-memory expansion could be achieved by other vaccine platforms expressing IL-15., Introduction The human and nonhuman primate immune systems vary markedly within outbred populations, both phenotypically and functionally. Of significant medical importance, people mount variable immune responses to vaccines and infectious [...]

Lignin nanoparticles (LNPs) have gained great interest as a promising renewable nanomaterial toward value-added applications. This work investigated solution chemistry and particle–particle interaction force in the LNP formation aiming at a facile technique to balance amphiphilic properties of lignin for size-controlled synthesis. By facilely tuning solution chemistry, lignin with different amphiphilic properties can form the nanoparticles with 57–262 nm and dispersity index (Đ) less than 0.2 at an initial lignin concentration of 10–80 g L−1. A numerical estimation of particle size was established with Derjaguin–Landau–Verwey–Overbeek's (DLVO) theory and population balance equation (PBE) to evaluate the interaction energy of particles as the function of solution chemistry and lignin properties. In the developed DLVO–PBE model, lignin properties such as molecular weights and content of functional groups are closely related to the repulsive energy calculation in the particle collision and further determine the assembly patterns. The model can be applied to lignin with varied properties with high prediction accuracy, especially in the DLVO forces-driven aggregation. It also suggests that solvated lignin chains can involve the uneven electrostatic force field and non-DLVO forces leading to a broad/multi-modal size distribution. Overall, the combination of experimental and theoretical investigations provides new insights into assembly mechanisms of lignin molecules involved in the formation of nano-/submicron particles. [ABSTRACT FROM AUTHOR]

Chiroptical activity over a broad range is expected to enable numerous applications including bioimaging and nanothermometers. However, understanding the chemical mechanism behind producing multiscale chirality for broad range chiroptical activities remains challenging. Here, we present a simple multiscale chiral synthesis and elucidate the underlying chemical mechanism for the self-assembly of achiral copper sulfide nanoparticles (NPs). The initially achiral NPs assemble into anisotropically twisted structures with a distinct handedness depending on the chirality of the molecules in the solution. Importantly, we reveal for the first time, to our knowledge, that metal ions act as messengers that transfer chirality information from small molecules to microstructures. The resulting multiscale chiral structures exhibit strong and broad chiroptical activities ranging from the ultraviolet to the infrared. This study not only enhances the understanding of the mechanism of chiral self-assembly but also offers effective approaches to producing chiral inorganic materials with strong chiroptical activities for next-generation chiral material-based applications. [ABSTRACT FROM AUTHOR]

Melatonin (MT), a pineal gland hormone, regulates the sleep/wake cycle and is a potential biomarker for neurodegenerative disorders, depression, hypertension, and several cancers, including prostate cancer and hepatocarcinoma. The amperometric detection of MT was achieved using a sensor customized with ruthenium-incorporated carbon spheres (Ru–CS), possessing C- and O-rich catalytically active Ru surfaces. The non-covalent interactions and ion–molecule adducts between Ru and CS favor the formation of heterojunctions at the sensor–analyte interface, thus accelerating the reactions towards MT. The Ru–CS/Screen-printed carbon electrode (SPCE) sensor demonstrated the outstanding electrocatalytic oxidation of MT owing to its high surface area and heterogeneous rate constants and afforded a lower detection limit (0.27 μM), high sensitivity (0.85 μA μM −1 cm−2), and excellent selectivity for MT with the co-existence of crucial neurotransmitters, including norepinephrine, epinephrine, dopamine, and serotonin. High concentrations of active biomolecules, such as ascorbic acid and tyrosine, did not interfere with MT detection. The practical feasibility of the sensor for MT detection in pharmaceutical samples was demonstrated, comparable to the data provided on the product labels. The developed amperometric sensor is highly suitable for the quality control of medicines because of its low cost, simplicity, small sample size, speed of analysis, and potential for automation. [ABSTRACT FROM AUTHOR]

Organic photodetectors (OPDs) based on non‐fullerene acceptors (NFAs) have received considerable attention because of their potential for use in various commercial applications as near‐infrared (NIR) light sensing platforms. However, recent OPDs suffer from low NIR photoresponse and large dark/noise currents with narrow bandgap organic photoactive materials. Herein, a π‐bridge molecular engineering strategy replacing alkoxythienyl with benzothiadiazole for ultra‐narrow bandgap (ultra‐NBG) NFAs is designed to achieve simultaneously high photoresponse at NIR region and low noise current density, thereby leading to excellent NIR (≈1050 nm) detectivity (D*). The newly synthesized ultra‐NBG NFAs, namely COB and CBT with optical bandgaps below 1.14 eV, present high responsivity (R) with 0.369 and 0.080 A W−1, respectively, at a wavelength of 1050 nm. Especially, with effectively suppressed noise current density, COB‐based OPD exhibits a high NIR (≈1050 nm) D* value of 2.18 × 1011 cm Hz1/2 W−1 at −0.5 V bias. The obtained R and D* values for these NFAs exceed or are comparable to those of a commercial Si photodetector at 1050 nm. This work provides important insight into the π‐bridge molecular engineering strategy for ultra‐NBG NFAs, which facilitate achieving highly sensitive NIR OPDs with high NIR photoresponse and low dark/noise current. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate the effect of APIC, a mixture containing soy isoflavone and L-carnitine on running endurance. Male C57BL/6 mice were orally administered APIC for 8 weeks. The APIC group exhibited a significant increase in treadmill running time until exhaustion compared to the control group. The respiratory exchange ratio in the APIC group was lower, indicating an enhancement in fatty acid oxidative metabolism. Furthermore, APIC supplementation increased the proportion of oxidative myofibers. Biochemical parameters associated with endurance capacity were also affected by APIC, as evidenced by increased muscle ATP levels and decreased levels of muscle triglycerides and blood lactate. qPCR and immunoblot analysis of C2C12 myotubes and gastrocnemius muscles indicated that APIC treatment stimulated AMPK signaling, mitochondrial biogenesis, and fatty acid metabolism. Additionally, treatment with APIC led to an increased oxygen consumption rate in C2C12 myotubes. Collectively, these findings suggest that APIC supplementation enhances mitochondrial biogenesis, promotes a switch from glycolytic to oxidative fiber types, and improves fatty acid metabolism through the activation of the AMPK signaling pathway in murine skeletal muscle. Ultimately, these effects contribute to the enhancement of running endurance. [ABSTRACT FROM AUTHOR]