Proton

The nature of the axial ligand in high-valent iron-oxo heme enzyme intermediates and related synthetic catalysts is a critical structural element for controlling proton-coupled electron-transfer (PCET) reactivity of these species. Herein, we describe the generation and characterization of three new 6-coordinate, iron(IV)-oxo porphyrinoid-π-cation-radical complexes and report their PCET reactivity together with a previously published 5-coordinate analogue, FeIV (O)(TBP8 Cz+• ) (TBP8 Cz = octakis( p - tert -butylphenyl)corrolazinato3- ) ( 2 ) (Cho, K...

The membrane electrode assembly (MEA) is the core component of proton exchange membrane fuel cells (PEMFCs), which is the place where the reaction occurrence, the multiphase material transfer and the energy conversion, and the development of MEA with high activity and long stability are crucial for the practical application of PEMFCs. Currently, efforts are devoted to developing the regulation of MEA nanostructure engineering, which is believed to have advantages in improving catalyst utilization, maximizing three-phase boundaries, enhancing mass transport, and improving operational stability...

The flagellar motor proteins, MotA and MotB, form a complex that rotates the flagella by utilizing the proton motive force (PMF) at the bacterial cell membrane. Although PMF affects the susceptibility to aminoglycosides, the effect of flagellar motor proteins on the susceptibility to aminoglycosides has not been investigated. Here, we found that MotB overexpression increased susceptibility to aminoglycosides, such as kanamycin and gentamicin, in Bacillus subtilis without affecting swimming motility. MotB overexpression did not affect susceptibility to ribosome-targeting antibiotics other than aminoglycosides, cell wall-targeting antibiotics, DNA synthesis-inhibiting antibiotics, or antibiotics inhibiting RNA synthesis...

PURPOSE: Proton stereotactic radiosurgery (PSRS) has emerged as an innovative proton therapy modality aimed at achieving precise dose delivery with minimal impact on healthy tissues. This study explores the dosimetric outcomes of PSRS in comparison to traditional intensity-modulated proton therapy (IMPT) by focusing on cases with small target volumes. A custom-made aperture system designed for proton therapy, specifically tailored to small target volumes, was developed and implemented for this investigation...

Interest in applying proton-coupled electron transfer (PCET) reagents in reductive electro- and photocatalysis requires strategies that mitigate the competing hydrogen evolution reaction. Photoexcitation of a PCET donor to a charge-separated state (CSS) can produce a powerful H-atom donor capable of being electrochemically recycled at a comparatively anodic potential corresponding to its ground state. However, the challenge is designing a mediator with a sufficiently long-lived excited state for bimolecular reactivity...

Phytophthora parasitica is an oomycete pathogen that infects a broad range of crops of worldwide economic interest; among them are citrus species. In general, some Citrus and the rootstocks of related genera offer considerable resistance against P. parasitica ; therefore, understanding the mechanisms involved in the virulence of this pathogen is crucial. In this work, P. parasitica secondary metabolite production was studied using matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) and ultrahigh-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC/ESI-Q-TOF-MS) combined with chemometric tools, and its metabolic profile was evaluated under the influence of Citrus sunki (a highly susceptible host) and Poncirus trifoliata (a resistant genotype) extracts...

In recent years, anion exchange membranes (AEMs) have aroused widespread interest in hydrogen production via water electrolysis using renewable energy sources. The two current commercial low-temperature water electrolysis technologies used are alkaline water electrolysis (AWE) and proton exchange membrane (PEM) water electrolysis. The AWE technology exhibited the advantages of high stability and increased cost-effectiveness with low hydrogen production efficiency. In contrast, PEM water electrolysis exhibited high hydrogen efficiency with low stability and cost-effectiveness, respectively...

Investigating the oxygen transport law within the Membrane Electrode Assembly at intermediate temperatures (80-120 °C) is crucial for enhancing fuel cell efficiency. This study analyzed the resistance to oxygen transport within the Membrane Electrode Assembly at intermediate temperatures using limiting current density and electrochemical impedance spectroscopy. The study findings reveal that, as temperature progressively increases, the Ostwald ripening effect leads to a 34% rise in the local oxygen transport resistance (Rlocal ) in relation to the pressure-independent resistance (Rnp ) within the cathode catalytic layer...

The fungal plasma membrane H+ -ATPase (Pma1) pumps protons out of the cell to maintain the transmembrane electrochemical gradient and membrane potential. As an essential P-type ATPase uniquely found in fungi and plants, Pma1 is an attractive antifungal drug target. Two recent Cryo-EM studies on Pma1 have revealed its hexameric architecture, autoinhibitory and activation mechanisms, and proton transport mechanism. These structures provide new perspectives for the development of antifungal drugs targeting Pma1...

Using DNA as the next-generation medium for data storage offers unparalleled advantages in terms of data density, storage duration, and power consumption as compared to existing data storage technologies. To meet the high-speed data writing requirements in DNA data storage, this paper proposes a novel design for an ultra-high-density and high-throughput DNA synthesis platform. The presented design mainly leverages two functional modules: a dynamic random-access memory (DRAM)-like integrated circuit (IC) responsible for electrode addressing and voltage supply, and the static droplet array (SDA)-based microfluidic structure to eliminate any reaction species diffusion concern in electrochemical DNA synthesis...

Since the emergence of SARS-CoV-2 in late 2019, the global mortality attributable to COVID-19 has reached 6,972,152 deaths according to the World Health Organization (WHO). The association between coinfection with Clostridioides difficile (CDI) and SARS-CoV-2 has limited data in the literature. This retrospective study, conducted at Mureș County Clinical Hospital in Romania, involved 3002 ICU patients. Following stringent inclusion and exclusion criteria, 63 patients were enrolled, with a division into two subgroups-SARS-CoV-2 + CDI patients and CDI patients...

Concomitant therapy (CT) and bismuth quadruple therapy (BQT) are recommended in geographical areas with high clarithromycin resistance for Helicobacter pylori ( H. pylori ) eradication. We compared CT and BQT as the first lines of treatment in a randomized controlled trial. Consecutive patients with H. pylori diagnosed by concordance of both a urea breath test and histology were recruited. For BQT, patients received 3 PyleraTM capsules q.i.d.; for CT, 1000 mg of amoxicillin b.i.d, 500 mg of clarithromycin b...

A novel poly(dibenzofuran isatin) (PBFI) with π conjugated structure was synthesized. Through the facile ring-opening reaction, flexible and hydrophilic side chains with hydroxyl and quaternary ammounium groups were grafted into PBFI. Obtained PBFI- x %GTA membranes with twisted polymer structure and multiple hydrogen bonding sites displayed high HT-PEMFC performance.

1 H-1 H coupling constants are one of the primary sources of information for nuclear magnetic resonance (NMR) structural analysis. Several selective 2DJ experiments have been proposed that allow for their individual measurement at pure shift resolution. However, all of these experiments fail in the not uncommon case when coupled protons have very close chemical shifts. First, the coupling between protons with overlapping multiplets is inaccessible due to the inability of a frequency-selective pulse to invert just one of them...

For the practical application of fuel cells in vehicles, it is a challenge to develop a proton solid electrolyte that coexhibits thermal stability and high proton conductivity at wide intermediate temperatures. Here, we report on the tunnel structured phosphate KNi1- x H2 x (PO3 )3 ·y H2 O, which exhibits high proton conductivity at room temperature up to 500 °C, with the conductivity value reaching 1.7 × 10-2 S cm-1 at 275 °C for x = 0.18. This material, composed of the smallest cations that form the tunnel framework with face-shared (KO6 ) and (NiO6 ) chains and PO4 tetrahedral chains, retained the rigid framework up to 600 °C...

Acid transport is required for bone synthesis by osteoblasts. The osteoblast basolateral surface extrudes acid by Na+ /H+ exchange, but apical proton uptake is undefined. We found high expression of the Cl- /H+ exchanger ClC3 at the bone apical surface. In mammals ClC3 functions in intracellular vesicular chloride transport, but when we found Cl- dependency of H+ transport in osteoblast membranes, we queried whether ClC3 Cl- /H+ exchange functions in bone formation. We used ClC3 knockout animals, and closely-related ClC5 knockout animals: In vitro studies suggested that both ClC3 and ClC5 might support bone formation...

PURPOSE: To assess the utility of fat fraction quantification using quantitative multi-echo Dixon for evaluating tumor proliferation and microvascular invasion (MVI) in hepatocellular carcinoma (HCC). METHODS: A total of 66 patients with resection and histopathologic confirmed HCC were enrolled. Preoperative MRI with proton density fat fraction and R2 * mapping was analyzed. Intratumoral and peritumoral regions were delineated with manually placed regions of interest at the maximum level of intratumoral fat...

In this report, we describe proton-coupled electron transfer (PCET) reactivity at the surface of the Keggin-type polyoxotungstate cluster [ n Bu4 N]3 [PWVI 12 O40 ] ( PW 12 ) in acetonitrile. Bond dissociation free energies (BDFEs) of the O-H groups generated upon reduction of PW 12 in the presence of acid are determined through the construction of a potential-p K a diagram. The surface O-H bonds are found to be weak (BDFE(O-H)avg < 48 kcal mol-1 ), comparable to the BDFE of H2 . This is consistent with the observed formation of H2 upon addition of a suitably strong organic acid, H2 NPh2 + (p K a MeCN = 5...

Electrochemical CO2 reduction reaction (CO2RR) offers a sustainable strategy for producing fuels and chemicals. However, it suffers from sluggish CO2 activation and slow water dissociation. In this work, we construct a (P-O)δ- modified In catalyst that exhibits high activity and selectivity in electrochemical CO2 reduction to formate. A combination of in-situ characterizations and kinetic analyses indicate that (P-O)δ- has a strong interaction with K+(H2O)n, which effectively accelerates water dissociation to provide protons...

Enzymatic recycling of plastic and especially of polyethylene terephthalate (PET) has shown great potential to reduce its negative impact on our society. PET hydrolases (PETases) have been optimized using rational design and machine learning, but the mechanistic details of the PET depolymerization process remain unclear. Belonging to the carboxylic-ester hydrolase family with a canonical Ser-His-Asp catalytic triad, their observed alkaline pH optimum is generally thought to be related to the protonation state of the catalytic His...