Ferroelectric liquid crystal mixtures containing chiral ether and ester compounds with the 2-arylidene-p-menthan-3-one skeleton

Some 1R,4R-2-(4-phenylbenzylidene)-p-menthane-3-one derivatives containing the ether or ester linking group between benzene rings of the arylidene fragment have been studied as chiral dopants in ferroelectric liquid crystal systems based on the eutectic mixture (1:1) of two phenylbenzoate derivatives CmH2m+1OC6H4COOC6 H4OCnH2n+1 (n = 6; m = 8, 10). The ferroelectric properties of these compositions (spontaneous polarization, rotation viscosity, smectic tilt angle as well as quantitative characteristics of their concentration dependences) were compared with those for systems including chiral dopants containing no linking group. Ferroelectric parameters of the induced ferroelectric compositions studied have been shown to depend essentially on the presence of the linking group between benzene rings and its nature as well as on the number of the benzene rings in the rigid molecular core of the chiral dopants used. For all ferroelectric liquid crystal systems studied, the influence of the chiral dopants on the thermal stability of N*, SmA and SmC* mesophases has been quantified. The influence of the linking group nature in the dopant molecules on the characteristics of the systems studied is discussed taking into account results of the conformational analysis carried out by the semi-empirical AM1 and PM3 methods.

Preservation of Sardinella longiceps in iced and chilled seawater. Part 1 - Changes during storage with particular reference to bacterial load and nitrogenous compounds

Oil sardines in prime condition were subjected to onboard chilling. Two lots were chilled in CSW (samples C and CI), a third lot was chilled in crushed ice (sample I) and a fourth lot left not iced on deck (Sample AI). Upon landing sample AI was iced and sample CI was removed from the CSW and iced. All the four samples were kept in a chilled room for storage studies. The fish chilled and stored in CSW recorded the least, and the fish subjected to delayed icing, the highest values for all the indices of spoilage namely, free amino nitrogen, trimethylamine (TMA) and total volatile base nitrogen (TVBN). The total psychrophilic bacterial number also showed a similar trend. The organoleptic assessment of the cooked samples revealed C I, CI, AI to be the order of preference throughout the storage. This assessment was found to hold good for the rest of the parameters as well. The CSW held fishes were found to be distinctly superior to the iced ones for the first five days of storage. Such a marked prevalence in quality for five days would suffice for the fish to fetch a premium in the market over other landings of the same fish whether chilled or not chilled. Chilling on board in CSW and icing the same after landings, did not show encouraging results.

Two new compounds and anti-HIV active constituents from Illicium verum

Two new compounds named illiverin A (1) and tashironin A (8) were, isolated from the roots of Illicium verum, together with seven known compounds: 4-allyl-2-(3-methylbut-2-enyl)-1,6-methylenedioxybenzene-3-ol (2), illicinole (3), 3-hydroxy-4,5-methylenedi

Three new compounds from Kadsura longipedunculata

Two new tetrahydrofuran lignans, kadlongirins A and B (1, 2), a new cadinane-type sesquiterpenoid, 2,7-dihydroxy-1 1,1 2-dehydrocalamenene (3), together with seven known lignans, grandisin, fragransin B-1, vladirol F, kadsuralignan C, otobaphenol, isoanwu

Anti-HIV-1 activities of compounds isolated from the medicinal plant Rhus chinensis

Aim of the study: Previously, we reported that the petroleum ether fraction, RC-1, and EtOAc fraction, RC-2, of the medicinal plant Rhus chinensis showed potent anti-HIV-1 activities. To address anti-HIV-1 constituents of RC-1 and RC-2, 17 compounds were

Compounds from Kadsura heteroclita and related anti-HIV activity

Phytochemical investigation of the stems of Kadsura heteroclita led to isolation of 16 compounds, including the triterpenoid named longipcdlactone J (2), and two dibenzocyclooctadiene type lignans named heteroclitin I and J (3, 4). Compounds 8-10, 14, and

Anti-HIV Activities of the Compounds Isolated from Polygonum cuspidatum and Polygonum multiflorum

The 70% EtOH extract of Polygonum cuspidatum showed inhibitory action against HIV-1-induced syncytium formation at non-cytotoxic concentrations in vitro with a 50% effective concentration (EC50) of 13.94 +/- 3.41 mu g/mL. Through bioactivity-guided fractionation, 20 phenolic compounds, including eight stilbenoids, were isolated from the roots of Polygonum cuspidatum, and their anti-HIV-1 activities were evaluated. Results showed that compounds 1, 13, 14, and 16 demonstrated fairly strong antiviral activity against HIV-1-induced cytopathic effects in C8166 lymphocytes at non-cytotoxic concentrations, with EC50 values of 4.37 +/- 1.96 mu g/mL, 19.97 +/- 5.09, 14.4 +/- 1.34 mu g/mL, and 11.29 +/- 6.26 mu g/mL and therapeutic index (TI) values of 8.12, > 10.02, > 13.89, and > 17.71, respectively. Other compounds showed either weak or no effects. Compound 6 also showed weak inhibition (153.42 +/- 19.25 mu g/mL); however, it possesses very good water solubility and showed almost no cytotoxicity (> 2000 mu g/mL), therefore achieving a fairly good TI (13.04). The activities of the two compounds (3 and 18) from Polygonum multiflorum were also assayed. The relationship between molecular structures and their bioactivities was also discussed.

Extraction and structure elucidation of natural compounds of some gorgonians of the Persian Gulf and also physiological and pharmacological effects of gorgonian extract on some selected organisms

In the present research, investigations were carried out for structure elucidation of natural compounds and also for studing biological and teratogenical effects of two Genus of soft corals named as " Echinogorgia cf. indica" and "Sinularia erecta" in Persian Gulf. First, 350 gr Echinogorgia was extracted by Acetone, then, the extract was separated by ether from aqueos phase to give 4.5 gr oil. The oil eluted with Petrol - ether Et2 o (9:1) which was recovered Linderazulene and it's derivative as purple Cristals (350 mg/ca 0.1 %). In order to determine molecular structure, the Samples were used for spectroscopic method as: H1- NMR , C13- NMR and 2D NMR. Also, for extraction and structure elucidation of natural compounds, the soft coral " sinularia erecta " were used 1187/37 gr and extracted by Aceton. The extract was concentrated and resulting aqueous suspension and extracted by using ether to give 8.41 gr oil. The oil , was Chromatographed on a column of silica gel and some different fractions were gathered. Initial fraction (1-11) which were nonpolar compounds were seprated by GC/MS. Mass spectrum were prepared and much compounds were recognized.

A review of the distribution of organic compounds in freshwater lakes and rivers

The paper reviews the distribution of organic compounds in freshwater lakes and rivers. The study of dissolved organic matter in natural lakes and rivers is of importance for a variety of reasons. The organic matter may serve in part or whole as an energy source for organisms living in the aquatic environment, or it may supply them with materials essential for their nutrition.

Metal-polymer composite sensors for volatile organic compounds: Part 1. Flow-through chemi-resistors

A new type of chemi-resistor based on a novel metal-polymer composite is described. The composite contains nickel particles with sharp nano-scale surface features, which are intimately coated by the polymer matrix so that they do not come into direct physical contact. No conductive chains of filler particles are formed even at loadings above the percolation threshold and the composite is intrinsically insulating. However, when subjected to compression the composite becomes conductive, with sample resistance falling from ≥ 1012 Ω to < 0.01 Ω. The composite can be formed into insulating granules, which display similar properties to the bulk form. A bed of granules compressed between permeable frits provides a porous structure with a start resistance set by the degree of compression while the granules are free to swell when exposed to volatile organic compounds (VOCs). The granular bed presents a large surface area for the adsorption of VOCs from the gas stream flowing through it. The response of this system to a variety of vapours has been studied for two different sizes of the granular bed and for different matrix polymers. Large responses, ΔR/R0 ≥ 10^7, are observed when saturated vapours are passed through the chemi-resistor. Rapid response allows real time sensing of VOCs and the initial state is recovered in a few seconds by purging with an inert gas stream. The variation in response as a function of VOC concentration is determined.

Spray drying: An alternative synthesis method for polycationic oxide compounds

Synthesis of polycationic compounds by the spray-drying technique is an interesting alternative in the domain of aqueous precursor synthesis methods. Spray drying yields high quality samples with good reproducibility. The possibility of scaling up for production of large quantities with fast processing time is well established by the commercial availability of powders of various compositions. In this paper, we have discussed the advantages and limitations of this method and demonstrated its interest by synthesizing a few polycationic compounds selected for their attractive properties of thermoelectricity [Bi1.68Ca2Co1.69O 8, La0.95A0.05CoO3 (A=Ca, Sr, Ba)] or magnetoresistance [La0.70A0.30MnO3 (A=Sr, Ba)]. We have confirmed the quality of these samples by reporting their structure, magnetic and transport properties. © 2010 Elsevier Ltd All rights reserved.

LiMn2-xTixO4 spinel-type compounds (x ≤ 1): Structural, electrical and magnetic properties

LiMn2-xTixO4 compounds with 0 ≤ x ≤ 1 were prepared by solid state reaction and Pechini technique. Powder X-ray diffraction showed that all samples crystallize with the spinel crystal structure (S.G. Fd3-m). The cubic unit-cell parameter increases with the Ti content. The influence of the Ti content and cationic distribution on the magnetic properties of the compounds was studied by measuring the temperature and magnetic field dependences of the magnetization: substitution by non-magnetic d0 Ti4+ ions appeared to weaken the magnetic interactions between the manganese ions. The electrical properties of LiMnTiO4 were studied by AC impedance spectroscopy and DC polarisation measurements, which revealed the electronic character of the conduction process. © 2006 Elsevier B.V. All rights reserved.