Quantum Evolution beyond the Markovian Semigroup — Generalizing the Stenholm–Barnett Approach

We provide conditions for the memory kernel governing the time-nonlocal quantum master equation which guarantee that the corresponding dynamical map is completely positive and trace-preserving. This approach gives rise to the new parametrization of dynamical maps in terms of two completely positive maps – so-called legitimate pair. In fact, these new parameterizations are a natural generalization of Markovian semigroup. Interestingly our class contains recently studied models like semi-Markov evolution and collision models.     

Fiber Preparation from Micronized Oat By-Products: Antioxidant Properties and Interactions between Bioactive Compounds

This study aimed to investigate the possibility of utilizing oat by-products for fiber preparation. Oat husk (OH) and oat bran (OB) were micronized and used to prepare a novel product rich in fiber and with enhanced antioxidant properties. The basic chemical composition and phenolic acid profile were determined in OH and OB. The antioxidant properties of OH and OB were also analyzed. The type and strength of interactions between the biologically active compounds from their mixtures were characterized by an isobolographic analysis. The analyses showed that the sum of phenolic acids was higher in OH than in OB. Ferulic acid was dominant in both OH and OB; however, its content in OH was over sixfold higher than that in OB. The results also suggested that both OH and OB can be used for preparing fiber with enhanced antioxidant properties. The optimal composition of the preparation, with 60–70% of OH and 30–40% of OB, allows for obtaining a product with 60–70% fiber and enhanced antioxidant activity due to bioactive substances and their synergistic effect. The resulting product can be a valuable additive to various food and dietary supplements.     

Modulation of the MOP Receptor (μ Opioid Receptor) by Imidazo[1,2-a]imidazole-5,6-Diones: In Search of the Elucidation of the Mechanism of Action

The μ-opioid receptors belong to the family of G protein-coupled receptors (GPCRs), and their activation triggers a cascade of intracellular relays with the final effect of analgesia. Classical agonists of this receptor, such as morphine, are the main targets in the treatment of both acute and chronic pain. However, the dangerous side effects, such as respiratory depression or addiction, significantly limit their widespread use. The allosteric centers of the receptors exhibit large structural diversity within particular types and even subtypes. Currently, a considerable interest is aroused by the modulation of μ-opioid receptors. The application of such a technique may result in a reduction in the dose or even discontinuation of classical opiates, thus eliminating the side effects typical of this class of drugs. Our aim is to obtain a series of 1-aryl-5,6(1H)dioxo-2,3-dihydroimidazo[1,2-a]imidazole derivatives and provide more information about their activity and selectivity on OP3 (MOP, human mu opioid receptor). The study was based on an observation that some carbonyl derivatives of 1-aryl-2-aminoimidazoline cooperate strongly with morphine or DAMGO in sub-threshold doses, producing similar results to those of normal active doses. To elucidate the possible mechanism of such enhancement, we performed a few in vitro functional tests (involving cAMP and β-arrestin recruitment) and a radioligand binding assay on CHO-K1 cells with the expression of the OP3 receptor. One of the compounds had no orthosteric affinity or intrinsic activity, but inhibited the efficiency of DAMGO. These results allow to conclude that this compound is a negative allosteric modulator (NAM) of the human μ-opioid receptor.     

Physicochemical Properties and Surface Characteristics of Ground Human Teeth

Enamel, dentin and cementum apatite has a complex composition. The lack of complete reports on the chemical composition of all tooth tissues together and the need to create a modern biomaterial that reproduces the correct ratio of individual tooth mineral components prompted the authors to undertake the research. A detailed evaluation of the micro- and macro-elements of tooth powder, using various methods of chemical analysis was conducted. All four groups of human sound teeth were crushed using the grinder. A fine powder was implemented for the FTIR (Fourier Transform Infrared Spectroscopy), ICP (Inductively Coupled Plasma Optical Emission Spectometry) and for the potentiometric titration, SEM and mercury porosimetry analyses. The obtained studies indicate that there is no significant correlation in chemical composition between the different teeth types. This proves that every removed, crushed tooth free of microorganisms can be a suitable material for alveolar augmentation. It is essential to know the chemical profiles of different elements in teeth to develop a new class of biomaterials for clinical applications.     

Responses of Adult Hypera rumicis L. to Synthetic Plant Volatile Blends

The behavioral responses of Hypera rumicis L. adults to varying blends of synthetic plant volatiles (SPVs) at various concentrations in lieu of single compounds are reported for the first time. For this study, Rumex confertus plants were treated with two blends of SPVs at different quantities that act as either attractants or repellents to insects. Blend 1 (B1) consisted of five green leaf volatiles (GLVs), namely (Z)-3-hexenal, (E)-2-hexenal, (Z)-3-hexenol, (E)-2-hexenol, and (Z)-3-hexen-1-yl acetate. Blend 2 (B2) contained six plant volatiles, namely (Z)-ocimene, linalool, benzyl acetate, methyl salicylate, β-caryophyllene, and (E)-β-farnesene. Each blend was made available in four different amounts of volatiles, corresponding to each compound being added to 50 µL of hexane in amounts of 1, 5, 25 and 125 ng. The effects of the two blends at the different concentrations on the insects were evaluated using a Y-tube olfactometer. Both sexes of the insects were found to be significantly repelled by the highest volatile levels of B1 and by two levels of B2 (25 and 125 ng). Females were also observed to be repelled using B2 with 5 ng of each volatile. Attraction was observed for both sexes only for B1 at the three lower volatile levels (1, 5 and 25 ng). In additional experiments, using only attractants, unmated females were found to be attracted to males, whereas mated females were only attracted to B1. Both unmated and mated males (previously observed in copula) were attracted only to females.     

The Synthesis Methodology of PEGylated Fe3O4@Ag Nanoparticles Supported by Their Physicochemical Evaluation

Many investigations are currently being performed to develop the effective synthesis methodology of magnetic nanoparticles with appropriately functionalized surfaces. Here, the novelty of the presented work involves the preparation of nano-sized PEGylated Fe₃O₄@Ag particles, i.e., the main purpose was the synthesis of magnetic nanoparticles with a functionalized surface. Firstly, Fe₃O₄ particles were prepared via the Massart process. Next, Ag+ reduction was conducted in the presence of Fe₃O₄ particles to form a nanosilver coating. The reaction was performed with arabic gum as a stabilizing agent. Sound energy-using sonication was applied to disintegrate the particles’ agglomerates. Next, the PEGylation process aimed at the formation of a coating on the particles’ surface using PEG (poly(ethylene glycol)) has been performed. It was proved that the arabic gum limited the agglomeration of nanoparticles, which was probably caused by the steric effect caused by the branched compounds from the stabilizer that adsorbed on the surface of nanoparticles. This effect was also enhanced by the electrostatic repulsions. The process of sonication caused the disintegration of aggregates. Formation of iron (II, III) oxide with a cubic structure was proved by diffraction peaks. Formation of a nanosilver coating on the Fe₃O₄ nanoparticles was confirmed by diffraction peaks with 2θ values 38.15° and 44.35°. PEG coating on the particles’ surface was proven via FT-IR (Fourier Transform Infrared Spectroscopy) analysis. Obtained PEG–nanosilver-coated Fe₃O₄ nanoparticles may find applications as carriers for targeted drug delivery using an external magnetic field.     

Combination of solid-state NMR,molecular mechanics and DFT calculations for the molecular structure determination of methyl glycoside benzoates

Structural Chemistry - A reliable method for molecular structure determination, excluding single-crystal X-ray diffraction (SCXRD), has been applied to six methyl glycoside tetrabenzoates. The...     

ChemInform Abstract: Influence of Hydrogen Absorption on Structural and Magnetic Properties of Ce2Ni2In.

Ce₂Ni₂InH_x hydrides with x < 2 retain the Mo₂FeB₂‐type structure of Ce₂Ni₂In and crystallize in the tetragonal space group P4/mbm (powder XRD).     

Reactivity of the >P‐O− nucleophiles toward arylmethyl chloride systems*†

The reactions of sodium dimethyl and diisopropyl phosphite, as well as dibenzylphosphinite with 4‐nitrobenzyl chloride, 9‐chlorofluorene, and diphenylchloromethane were studied in detail by the isolation and identification of all the products, and the examination of the effects of the solvents on the product distribution. The results of the performed experiments are compatible with the proposed mechanism: a >P‐O⁻ anion acts toward an arylmethyl chloride as a base and abstracts a proton to form a carbanion, which can then participate in the SET processes to produce carbon‐centered radicals. Additionally, the >P‐O⁻ reagent can act as a carbon‐centered radical trap if it is present in a high enough concentration. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 431–439, 1999