Determining Rate Coefficients for the 11-Atom Reaction via Ring Polymer Molecular Dynamics Based on a 27-Dimensional Potential Energy Surface: The Reaction between -CHCHOO and HO.

Criegee intermediates (CIs) are potentially significant oxidants and a major source of OH radicals in the troposphere. The -CHCHOO intermediate has been confirmed as a crucial component of CIs in the atmospheric environment. Although previous studies have provided some experimental and theoretical rate constants, inconsistencies among these data remain, and the experimental data do not cover the full range of temperatures present in the troposphere.

Endoplasmic reticulum stress and autophagy in cerebral ischemia/reperfusion injury: PERK as a potential target for intervention.

JOURNAL/nrgr/04.03/01300535-202505000-00028/figure1/v/2024-07-28T173839Z/r/image-tiff Several studies have shown that activation of unfolded protein response and endoplasmic reticulum (ER) stress plays a crucial role in severe cerebral ischemia/reperfusion injury. Autophagy occurs within hours after cerebral ischemia, but the relationship between ER stress and autophagy remains unclear.

Demethylation C-C coupling reaction facilitated by the repulsive Coulomb force between two cations.

Carbon chain elongation (CCE) is normally carried out using either chemical catalysts or bioenzymes. Herein we demonstrate a catalyst-free approach to promote demethylation C-C coupling reactions for advanced CCE constructed with functional groups under ambient conditions. Accelerated by the electric field, two organic cations containing a methyl group (e.

Supercollisions of NaCl + NaCl on an Accurate Full-Dimensional Potential Energy Surface.

An accurate, global, full-dimensional potential energy surface (PES) of NaCl + NaCl has been constructed by the fundamental invariant-neural network (FI-NN) fitting based on roughly 13,000 ab initio energies at the level of CCSD(T)-F12a/aug-cc-pVTZ, with the small fitting error of 0.16 meV. Extensive quasiclassical trajectory (QCT) calculations were performed on this PES to investigate the energy transfer process of the NaCl + NaCl collision at four different collision energies.

Roaming in highly excited states: The central atom elimination of triatomic molecule decomposition.

Chemical reactions are generally assumed to proceed from reactants to products along the minimum energy path (MEP). However, straying from the MEP-roaming-has been recognized as an unconventional reaction mechanism and found to occur in both the ground and first excited states. Its existence in highly excited states is however not yet established.

Multiple Dissociation Pathways in HNCO Decomposition Governed by Potential Energy Surface Topography.

The exquisite features of molecular photochemistry are key to any complete understanding of the chemical processes governed by potential energy surfaces (PESs). It is well established that multiple dissociation pathways relate to nonadiabatic transitions between multiple coupled PESs. However, little detail is known about how the single PES determines reaction outcomes.

Roaming Dynamics in Hydroxymethyl Hydroperoxide Decomposition Revealed by the Full-Dimensional Potential Energy Surface of the CHOO + HO Reaction.

The CHOO + HO reaction is an important atmospheric process that leads to the formation of formic acid (HCOOH) and water via the intermediate hydroxymethyl hydroperoxide (HOCHOOH, HMHP). We investigated the intricacies of this process by employing quasiclassical trajectory calculations on an accurate, full-dimensional ab initio potential energy surface (PES). In addition to the direct mechanism via the transition state (TS), an interesting roaming mechanism was found to play the predominant role in producing HO and HCOOH.

Vacuum ultraviolet photodissociation of sulfur dioxide and its implications for oxygen production in the early Earth's atmosphere.

The emergence of molecular oxygen (O) in the Earth's primitive atmosphere is an issue of major interest. Although the biological processes leading to its accumulation in the Earth's atmosphere are well understood, its abiotic source is still not fully established. Here, we report a new direct dissociation channel yielding S(D) + O(aΔ/XΣ) products from vacuum ultraviolet (VUV) photodissociation of SO in the wavelength range between 120 and 160 nm.

Full-dimensional neural network potential energy surface and dynamics of the CHOO + HO reaction.

An accurate global full-dimensional machine learning-based potential energy surface (PES) of the simplest Criegee intermediate (CHOO) reaction with water monomer was developed based on the high level of extensive CCSD(T)-F12a/aug-cc-pVTZ calculations. This analytical global PES not only covers the regions of reactants to hydroxymethyl hydroperoxide (HMHP) intermediates, but also different end product channels, which facilities both the reliable and efficient kinetics and dynamics calculations. The rate coefficients calculated by the transition state theory with the interface to the full-dimensional PES agree well with the experimental results, indicating the accuracy of the current PES.

APP mediates tau uptake and its overexpression leads to the exacerbated tau pathology.

Alzheimer's disease (AD), as the most common type of dementia, has two pathological hallmarks, extracellular senile plaques composed of β-amyloid peptides and intracellular neurofibrillary tangles containing phosphorylated-tau protein. Amyloid precursor protein (APP) and tau each play central roles in AD, although how APP and tau interact and synergize in the disease process is largely unknown. Here, we showed that soluble tau interacts with the N-terminal of APP in vitro in cell-free and cell culture systems, which can be further confirmed in vivo in the brain of 3XTg-AD mouse.

A highly accurate full-dimensional potential surface for the rearrangement of methylhydroxycarbene (HC-C-OH).

We report here a full-dimensional machine learning global potential surface (PES) for the rearrangement of methylhydroxycarbene (HC-C-OH, 1t). The PES is trained with the fundamental invariant neural network (FI-NN) method on 91 564 energies calculated at the UCCSD(T)-F12a/cc-pVTZ level of theory, covering three possible product channels. FI-NN PES has the correct symmetry properties with respect to permutation of four identical hydrogen atoms and is suitable for dynamics studies of the 1t rearrangement.

Infection of Human Macrophages Retains Golgi Structure but Reduces O-Glycans.

is an accidental pathogen that replicates intracellularly within the -containing vacuole (LCV) in macrophages. Within an hour of infection, secretes effectors to manipulate Rab1 and intercept ER-derived vesicles to the LCV. The downstream consequences of interrupted ER trafficking on the Golgi of macrophages are not clear.

Observation of Competitive Nonadiabatic Photodissociation Dynamics of HS Cations.

A comprehensive understanding of dissociation mechanisms is of fundamental importance in the photochemistry of small molecules. Here, we investigated the detailed photodissociation dynamics of HS near 337 nm by using the velocity map ion imaging technique together with the theoretical characterizations by developing global full-dimensional potential energy surfaces (PESs). Rotational state resolved images were acquired for the S(S) + H product channel.

Double-Roaming Dynamics in the H + CH → H + CH Reaction: Acetylene-Facilitated Roaming and Vinylidene-Facilitated Roaming.

We report two novel roaming pathways for the H + CH → H + CH reaction by performing extensive quasiclassical trajectory calculations on a new, global, high-level machine learning-based potential energy surface. One corresponds to the acetylene-facilitated roaming pathway, where the H atom turns back from the acetylene + H channel and abstracts another H atom from acetylene. The other is the vinylidene-facilitated roaming, where the H atom turns back from the vinylidene + H channel and abstracts another H from vinylidene.

Supercollisions of fast H-atom with ethylene on an accurate full-dimensional potential energy surface.

The collisions transferring large portions of energy are often called supercollisions. In the H + CH reactive system, the rovibrationally cold CH molecule can be activated with substantial internal excitations by its collision with a translationally hot H atom. It is interesting to investigate the mechanisms of collisional energy transfer in other important reactions of H with hydrocarbons.

Collision-induced and complex-mediated roaming dynamics in the H + CH → H + CH reaction.

Roaming is a novel mechanism in reaction dynamics. It describes an unusual pathway, which can be quite different from the conventional minimum-energy path, leading to products. While roaming has been reported or suggested in a number of unimolecular reactions, it has been rarely reported for bimolecular reactions.

Influence of physiological and environmental factors on the diurnal variation in emissions of biogenic volatile compounds from Pinus tabuliformis.

Biological volatile organic compounds (BVOCs) have a large influence on atmospheric environmental quality, climate change and the carbon cycle. This study assesses the composition and diurnal variation in emission rates of BVOCs from Pinus tabuliformis, using an enclosure technique. Environmental parameters (temperature and light intensity) and physiological parameters (net photosynthetic rate, P; stomatal conductance, g; intercellular CO concentration, C; and transpiration rate, T) that may affect emission behavior were continuously monitored.

LMAN1 (ERGIC-53) promotes trafficking of neuroreceptors.

The endoplasmic reticulum-Golgi intermediate compartment protein-53 (ERGIC-53, aka LMAN1), which cycles between the endoplasmic reticulum (ER) and Golgi, is a known cargo receptor for a number of soluble proteins. However, whether LMAN1 plays a role as a trafficking factor in the central nervous system is largely unknown. Here, we determined the role of LMAN1 on endogenous protein levels of the Cys-loop superfamily of neuroreceptors, including gamma-aminobutyric acid type A receptors (GABARs), 5-hydroxytryptamine (serotonin) type 3 (5-HT) receptors, and nicotinic acetylcholine receptors (nAChRs).

Remodeling the endoplasmic reticulum proteostasis network restores proteostasis of pathogenic GABAA receptors.

Biogenesis of membrane proteins is controlled by the protein homeostasis (proteostasis) network. We have been focusing on protein quality control of γ-aminobutyric acid type A (GABAA) receptors, the major inhibitory neurotransmitter-gated ion channels in mammalian central nervous system. Proteostasis deficiency in GABAA receptors causes loss of their surface expression and thus function on the plasma membrane, leading to epilepsy and other neurological diseases.

Indoor simulations reveal differences among plant species in capturing particulate matter.

A number of studies have focused on the capacity of urban trees and shrubs to serve as efficient biological filters to mitigate air pollution. In this study, five different tree species were assessed for this function. Kerria japonica, Sophora japonica, Philadelphus pekinensis, Gleditsia sinensis, and Prunus persica 'Atropurpurea' were tested in a deposition chamber using (NH4)2SO4 particles.

Grp94 Protein Delivers γ-Aminobutyric Acid Type A (GABAA) Receptors to Hrd1 Protein-mediated Endoplasmic Reticulum-associated Degradation.

Proteostasis maintenance of γ-aminobutyric acid type A (GABAA) receptors dictates their function in controlling neuronal inhibition in mammalian central nervous systems. However, as a multisubunit, multispan, integral membrane protein, even wild type subunits of GABAA receptors fold and assemble inefficiently in the endoplasmic reticulum (ER). Unassembled and misfolded subunits undergo ER-associated degradation (ERAD), but this degradation process remains poorly understood for GABAA receptors.

Proteostasis Maintenance of Cys-Loop Receptors.

The Cys-loop receptors play prominent roles in the nervous system. They include γ-aminobutyric acid type A receptors, nicotinic acetylcholine receptors, 5-hydroxytryptamine type-3 receptors, and glycine receptors. Proteostasis represents an optimal state of the cellular proteome in normal physiology.

Combining valosin-containing protein (VCP) inhibition and suberanilohydroxamic acid (SAHA) treatment additively enhances the folding, trafficking, and function of epilepsy-associated γ-aminobutyric acid, type A (GABAA) receptors.

GABAA receptors are the primary inhibitory ion channels in the mammalian central nervous system. The A322D mutation in the α1 subunit results in its excessive endoplasmic reticulum-associated degradation at the expense of plasma membrane trafficking, leading to autosomal dominant juvenile myoclonic epilepsy. Presumably, valosin-containing protein (VCP)/p97 extracts misfolded subunits from the endoplasmic reticulum membrane to the cytosolic proteasome for degradation.