Exploring potential energy surfaces to reach saddle points above convex regions.

Saddle points on high-dimensional potential energy surfaces (PES) play a determining role in the activated dynamics of molecules and materials. Building on approaches dating back more than 50 years, many open-ended transition-state search methods have been developed to follow the direction of negative curvature from a local minimum to an adjacent first-order saddle point. Despite the mathematical justification, these methods can display a high failure rate: using small deformation steps, up to 80% of the explorations can end up in a convex region of the PES, where all directions of negative curvature vanish, while if the deformation is aggressive, a similar fraction of attempts lead to saddle points that are not directly connected to the initial minimum.

Saturation magnetisation as an indicator of the disintegration of barium hexaferrite nanoplatelets during the surface functionalisation.

Barium hexaferrite nanoplatelets (BHF NPLs) are permanent nanomagnets with the magnetic easy axis aligned perpendicular to their basal plane. By combining this specific property with optimised surface chemistry, novel functional materials were developed, e.g.

Enzymatic Hydrolysis of Textile and Cardboard Waste as a Glucose Source for the Production of Limonene in .

Cellulose containing textiles (cotton) and cardboard/carton waste represent a large reservoir of untapped organic carbon. These wastes have enormous potential for use as carbon feedstock in industrial biotechnological processes. Essentially, cotton/cardboard (CC) waste is pure cellulose (with some additives) in the form of polymerised glucose consisting of β-(1→4)-linked D-glucose subunits.

Surprising Lateral Interactions between Negatively Charged Adatoms on Metal Surfaces.

Even something as conceptually simple as adsorption of electronegative adatoms on metal surfaces, where repulsive lateral interactions are expected for obvious reasons, can lead to unanticipated behavior. In this context, we explain the origin of surprising lateral interactions between electronegative adatoms observed on some metal surfaces by means of density functional theory calculations of four electronegative atoms (N, O, F, Cl) on 70 surfaces of 44 pristine metals. Four different scenarios for lateral interactions are identified, some of them being unexpected: (i) They are repulsive, which is the typical case and occurs on almost all transition metals.

Empirical Valence Bond Simulations of the Hydride-Transfer Step in the Monoamine Oxidase A Catalyzed Metabolism of Noradrenaline.

Monoamine oxidases (MAOs) A and B are flavoenzymes responsible for the metabolism of biogenic amines, such as dopamine, serotonin, and noradrenaline (NA), which is why they have been extensively implicated in the etiology and course of various neurodegenerative disorders and, accordingly, used as primary pharmacological targets to treat these debilitating cognitive diseases. The precise chemical mechanism through which MAOs regulate the amine concentration, which is vital for the development of novel inhibitors, is still not unambiguously determined in the literature. In this work, we present atomistic empirical valence bond simulations of the rate-limiting step of the MAO-A-catalyzed NA (norepinephrine) degradation, involving hydride transfer from the substrate α-methylene group to the flavin moiety of the flavin adenine dinucleotide prosthetic group, employing the full dimensionality and thermal fluctuations of the hydrated enzyme, with extensive configurational sampling.

A quantum chemical study of the reactivity of acetaminophen (paracetamol) toxic metabolite N-acetyl-p-benzoquinone imine with deoxyguanosine and glutathione.

Acetaminophen (APAP) forms some reactive metabolites that can react with DNA. APAP is a potentially genotoxic drug and is classified as a Group 3 drug according to International Agency for Research on Cancer (IARC). One of the possible mechanisms of APAP genotoxicity after long term of use is that its reactive quinone imine (QI) metabolite of acetaminophen (NAPQI), can chemically react with DNA after glutathione (GSH) depletion.

Use of a stable carbon isotope to assess the efficiency of a drinking water treatment method with CO₂.

CO₂ gas with a special isotopic signature (δ¹³C = -35.2‰ vs. VPDB) was used as a marker to evaluate the efficiency of a drinking water treatment method and the effect of an ultrasonic (US) stirrer.