Crystallographic report: The crystal structure of bis‐(3,3‐dimethyl‐3,4‐dihydro‐2H‐1‐thia‐4a,9‐diaza‐3‐sila‐fluorene) silver nitrate

The title compound is a silver nitrate complex with two molecules of 2‐mercaptobenzimidazole derivative. The silver atom lies on an inversion centre of the crystal lattice; nitrogen of the nitrate anion is in another inversion centre. Bond length Ag(1)? N(7) is 2.087(3) Å. Copyright © 2005 John Wiley & Sons, Ltd.     

Synthesis of novel phenanthroline derivatives by 3+2 dipolar cycloadition reaction

Eleven new 1,10‐phenanthroline derivatives have been prepared by 3+2 dipolar cycloaddition reactions of 1,10‐phenanthrolinium‐ylides 7–12 in situ generated from corresponded salts, with dimethyl acetylene‐dicarboxylate and ethyl propiolate.     

Synthesis and neurotropic activity of silyl propargyl alcohols and sulfides

New silicon derivatives of hetaryl propargyl sulfides and propargyl alcohols were synthesized using phase‐transfer catalytic and organometallic methods. These compounds were tested for acute toxicity and neurotropic activity in the pentylenetetrazole test, and for phenamine hypothermia, phenamine hyperactivity and passive avoidance response tests. We have found that the silyl propargyl alcohols and sulfides are low toxicity compounds, the LD₅₀ being 700–1300 mg kg^?1. In the PAR test, the synthesized compounds exerted some memory‐improving activity. For di‐1‐(3‐methyl‐3‐hydroxybutyn‐1‐yl)methyl(3‐iodopropyl)silane ( 16 ) the effect was statistically significant and amounted to 250% of the control level. In the pentylenetetrazole test, all compounds possessed anticonvulsant activity, the most active compounds being 3‐(benzoxazolylthio)‐1‐propynyl(trimethyl)silane ( 6 ) and di‐[2‐(1‐hydroxycyclohexyl)ethynyl]methyl(3‐iodopropyl)silane ( 17 ). The phenamine‐induced hyperactivity was significantly elevated after treatment with (3‐trimethylsilyl‐2‐propynyl)thiobenzene ( 1 ) or di‐[1‐(3‐methyl‐3‐hydroxybutyn‐1‐yl)diphenylsilane ( 12 ). Our data show that these silicon derivatives of hetaryl propargyl sulfides and propargyl alcohols possess certain memory improving and anticonvulsant activity that should be studied in detail to evaluate the receptor systems involved. Copyright © 2004 John Wiley & Sons, Ltd.     

New Polylactic Acid Composites for Packaging Applications: Mechanical Properties,Thermal Behavior,and Antimicrobial Activity

The interest in antimicrobial packaging materials based on polylactic acid (PLA) polymers has increased due to the need to improve food safety and environment quality and also to find alternatives to synthetic polymers made from petrochemicals. PLA films by addition of different fillers (grape wastes and celery fibers) were obtained. The mechanical, thermal, surface, and antimicrobial properties of the films were evaluated. The incorporation of inexpensive fillers into the PLA matrix could reduce costs and the studied formulations offer approaches to realize composites with high performances and antimicrobial response, suitable for film food-active packaging materials, especially by use of grape wastes.     

Characterization of the Phenolics and Free Radical Scavenging of Romanian Red Wine

The goal of the present work was to study the influence of winemaking procedures and the effect of bottle-aging on the antioxidant activity and on the variation of low molecular weight phenolics of Feteasca Neagra and Negru Aromat red wine from the Valea Calugareasca vineyard, Romania. The free radical-scavenging activity was measured using the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical from bottles sampled every 3 months up to the 9th month. The results indicated that Negru Aromat obtained by classical maceration had the highest activity at 6th month. The high-performance liquid chromatography results showed that the most abundant low molecular weight phenolic compounds were catechin, (?)-epicatechin, gallic acid, malvidin, and peonidin 3-O-glucoside. For the phenolics, Feteasca Neagra prepared by classical maceration and Negru Aromat by run-off juice were the richest. For anthocyanidins, the Feteasca Neagra and Negru Aromat wine by classical maceration had the highest concentrations. These results suggest that classical maceration is the winemaking procedure of choice to obtain the highest quality wine from the Valea Calugareasca vineyard.     

Sensory Rhodopsin I and Sensory Rhodopsin II Form Trimers of Dimers in Complex with their Cognate Transducers

Archaeal photoreceptors consist of sensory rhodopsins in complex with their cognate transducers. After light excitation, a two‐component signaling chain is activated, which is homologous to the chemotactic signaling cascades in enterobacteria. The latter system has been studied in detail. From structural and functional studies, a picture emerges which includes stable signaling complexes, which assemble to receptor arrays displaying hexagonal structural elements. At this higher order structural level, signal amplification and sensory adaptation occur. Here, we describe electron microscopy data, which show that also the archaeal phototaxis receptors sensory rhodopsin I and II in complex with their cognate transducers can form hexagonal lattices even in the presence of a detergent. This result could be confirmed by molecular dynamics calculations, which revealed similar structural elements. Calculations of the global modes of motion displayed one mode, which resembles the “U”‐”V” transition of the NpSRII:NpHtrII complex, which was previously argued to represent a functionally relevant global conformational change accompanying the activation process [Ishchenko et al. (2013) J. Photochem. Photobiol. B 123, 55‐58]. A model of cooperativity at the transmembrane level is discussed.     

Melissa officinalis L. Aqueous Extract Exerts Antioxidant and Antiangiogenic Effects and Improves Physiological Skin Parameters

Melissa officinalis (MO) is a medicinal plant well-known for its multiple pharmacological effects, including anti-inflammatory, anticancer and beneficial effects on skin recovery. In this context, the present study was aimed to investigate the in vitro and in vivo safety profile of an MO aqueous extract by assessing cell viability on normal (HaCaT—human keratinocytes) and tumor (A375—human melanoma) cells and its impact on physiological skin parameters by a non-invasive method. In addition, the antioxidant activity and the antiangiogenic potential of the extract were verified. A selective cytotoxic effect was noted in A375 cells, while no toxicity was noticed in healthy cells. The MO aqueous extract safety profile after topical application was investigated on SKH-1 mice, and an enhanced skin hydration and decreased erythema and transepidermal water loss levels were observed. The in ovo CAM assay, performed to investigate the potential modulating effect on the angiogenesis process and the blood vessels impact, indicated that at concentrations of 100 and 500 µg/mL, MO aqueous extract induced a reduction of thin capillaries. No signs of vascular toxicity were recorded at concentrations as high as 1000 μg/mL. The aqueous extract of MO leaves can be considered a promising candidate for skin disorders with impaired physiological skin parameters.     

Acylsilanes in Iridium‐Catalyzed Directed Amidation Reactions and Formation of Heterocycles via Siloxycarbenes

Exposing ortho‐amido aroylsilanes to visible light or heat leads to cyclization reactions that provide N‐heterocyclic compounds via siloxycarbenes as key intermediates. The previously unreported starting materials have been prepared by directed amidations of aromatic acylsilanes in the presence of an iridium catalyst followed by N‐alkylation.     

Theoretical Study of the Statistical Properties of Single- and Double-Pass M-Mode Er3+-Ti:LiNbO3 Straight Waveguide Amplifiers

Abstract

In this article, we report a theoretical study concerning some statistical parameters which characterize the single- and double-pass Er³⁺-doped Ti:LiNbO₃ M-mode straight waveguides. For the derivation and the evaluation of the Fano factor, the statistical fluctuation and the spontaneous emission factor we used a quasi two-level model in the small gain approximation and the unsaturated regime. The simulation results show the evolution of these parameters under various pump regimes and waveguide lengths. The obtained results can be used for the design of complex rare earth-doped integrated circuits.     

Intrinsic charm production of doubly charmed baryons:Collider vs. fixed-target

The LHCb Collaboration has measured the doubly charmed baryon,■^++cc(ucc),through two different decay channels[1,2]in p+p collisions at center-of-mass energies of 7,8 and 13 TeV.While they have performed similar searches for the doubly charmed baryon ■^+cc(dcc),it has not yet been observed by LHCb[3].However,the fixed-target experiment,SELEX,at Fermilab,reported the observation of the ■^+cc in two different decay channels with a 600 GeV charged hyperon beam[4,5].The beam was composed of an admixture of π^±,p,p components as well as the Σ^- hyperon.Much discussion has arisen over the fact that the fixed-target observations have not been easily reproduced by the collider experiments at higher energies,where one might have expected the production rates to be much higher due to the orders of magnitude increase in the center of mass energy with LHCb.