Application of a micro multiphase laminar flow on a microchip for extraction and determination of derivatized carbamate pesticides.

Determination of carbamate pesticides such as carbaryl, carbofuran, propoxur and bendiocarb was demonstrated on a microchip with newly designed microchannels developed for efficient solvent extraction. The pesticides were hydrolyzed to corresponding naphthols, coupled with p-nitrobenzenediazonium fluoroborate reagent, and then extracted into 1-butanol as colored azo derivatives and detected with a thermal lens microscope. Optimum flow rates for the aqueous and organic phases were evaluated in the continuous-flow chemical process established in the microchip. The calibration lines showed good linearity in the range of concentrations of 0.03 - 3 ppm (10(-7) - 10(-5) M) and a mass detection limit down to a nanogram level was achieved that is at least two orders of magnitude lower than the LODs for conventional spectrophotometric methods. Azo derivatives of the pesticides were successfully separated and identified by micellar electrokinetic chromatography (MEKC) using a sample prepared on a bulk scale.     

(R,R)-α,α′-Bis(trifluoromethyl)-9,10-anthracenedimethanol: a chiral solvating agent for enantiomeric resolution of β-dicarbonyl compounds

Commercially available (R,R)-α,α′-bis(trifluoromethyl)-9,10-anthracenedimetanol is a very efficient solvating agent for the enantiodifferentiation of a series of chiral Michael adducts and related β-dicarbonyl compounds.     

Superhydrophobic silica aerogels by fluorination at the gel stage

Superhydrophobic silica aerogels are obtained by surface modification of standard silica gels prepared by a two-step process with a heavily fluorinated silyl chloride followed by supercritical evacuation of the solvent.     

Carbon nanotube–polybithiophene photovoltaic devices with high open‐circuit voltage

We report the preparation of photovoltaic devices using modified single wall carbon nanotubes, SWNTs. Devices are produced stacking on top of fluorine‐doped tin‐oxide, an electrochemically deposited polybithiophene layer, a layer of SWNT blended with poly(3‐octylthiophene) and an evaporated top metal contact, Ca/Al or Al. Ca/Al‐top‐electrode devices achieve open‐circuit voltages of 1.81 V and average power conversion efficiency of 1.48% at irradiance of 15.5 W m^–2, spectrally distributed following AM1.5. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Eco-friendly combustion-based synthesis of metal aluminates MAl<Subscript>2</Subscript>O<Subscript>4</Subscript> (M = Ni,Co)

Nanosized metal aluminates, MAl₂O₄ (M = Ni, Co), have been prepared following a nonpolluting, low temperature, and self-sustaining starch single-fuel combustion synthesis. The mixed fuel-coordinating actions of starch have given rise to an intermediary precursor which afforded monodisperse metal aluminate nanoparticles. The thermal analysis of the [M(II), Al(III)]-starch precursors indicates a similar thermochemical reactivity for the two compounds, displaying a sequence of well-defined decomposition stages associated with three endothermic effects and three/four (nickel/cobalt) exothermic ones. The XRD data confirm the formation of spinelic phase and a continuous growth of particle sizes with the increase of calcination temperatures. The mechanisms proposed for the formation of metal aluminates essentially consist in a combination of solid-state reactions of amorphous NiO/Co₃O₄ and Al₂O₃ simple oxides. The evaluation criterion of Ni(II) cations into the spinelic lattice is original and is based on the distinct occupancy degree of tetrahedral and octahedral sites in NiAl₂O₄ and γ-Al₂O₃. TEM/HRTEM investigations performed on the cobalt(II) and nickel(II) aluminate oxide powders resulted after calcination at 800 and 900 °C, respectively, for 1 h show the formation of irregular and isolated plate-like particles for Co(II)-based spinelic oxides (the average particle size is 16.6 nm) and submicron aggregates of small, bimodal, and almost uniform (as shape and size) of NiAl₂O₄ mixed oxide (the mean particle size is 33.6 nm). The NIR–UV–Vis spectra for the resulted MAl₂O₄ (M = Co, Ni) mixed oxides reveal a massive presence of tetrahedral divalent cations both for short- and long-time calcined samples. NiO impurities are detected using FTIR and electronic spectra for all NiAl₂O₄ samples.     

Starch - A suitable fuel in new low-temperature combustion-based synthesis of zinc aluminate oxides

Starch has been tested as single-fuel and in a two-fuel mixture, together with N-methylurea, in a new combustion-based synthesis of zinc aluminate oxides, using different fuel compositions and equivalence ratios Φ_e (Φ_e = fuel/oxidant). The combustion process has been analyzed by simultaneous thermal analysis. The corresponding oxides were characterized by X-ray diffraction analysis, UV-Vis spectroscopy, scanning electron microscopy and BET investigations. Crystal structures were refined by Rietveld method. The morphology, specific surface area and optical properties of the obtained zinc aluminate have proved to be strongly dependent on the fuel nature and composition. The lowest crystallite size (131 Å) is achieved for the oxide generated from the starch-based precursor, while the highest surface area (20.69 m²/g) has been obtained for a 3:1 N-methylurea/starch fuel composition. The non-zero value for microstrain has indicated spinelic defects in the starch-fuel corresponding oxide. UV-Vis spectroscopic analysis have confirmed the intrinsic properties of the resulted mixed metal oxide, but also shows the presence of a certain disorder degree for all the other samples. The superior values of the band gap (4.2-4.7 eV) for the obtained oxides relative to the bulk case (3.8 eV) are the result of the nanometric dimensions of the particles.     

Toward molecular design for hazard reduction—fundamental relationships between chemical properties and toxicity

The relationship of in-silico predicted physical/chemical properties and human toxicity is analyzed for a statistically significant sample size of chemical compounds. Results for compounds with known toxicity endpoints, as designated by EPA's Toxic Release Inventory (TRI), are compared to a series of commercial chemicals that are not regulated under TRI. Physical properties for all compounds are predicted using Schrodinger's QikProp, an established tool for predicting adsorption, distribution, metabolism, and excretion (ADME) characteristics. The results of this analysis indicate that the physical/chemical property distributions of TRI chemicals are statistically significantly different from those of bulk commercial chemicals, particularly related to properties associated with bioavailability. Using a partitioning analysis, several key physical/chemical properties and ranges are identified that can be used to readily differentiate TRI chemical characteristics from those of bulk commercial chemicals.     

Anti-Inflammatory and Antioxidant Properties of Carvacrol and Magnolol,in Periodontal Disease and Diabetes Mellitus

Periodontal disease and diabetes mellitus are two pathologies that are extremely widespread worldwide and share the feature of chronic inflammation. Carvacrol is a phenolic monoterpenoid, produced by a variety of herbs, the most well-known of which is Origanum vulgare. Magnolol is a traditional polyphenolic compound isolated from the stem bark of Magnolia officinalis, mainly used in Chinese medicine. The purpose of this paper is to review the therapeutic properties of these bioactive compounds, in the treatment of periodontitis and diabetes. Based on our search strategy we conducted a literature search in the PubMed and Google Scholar databases to identify studies. A total of one hundred eighty-four papers were included in the current review. The results show that carvacrol and magnolol have anti-inflammatory, antioxidant, antimicrobial, anti-osteoclastic, and anti-diabetic properties that benefit both pathologies. Knowledge of the multiple activities of carvacrol and magnolol can assist with the development of new treatment strategies, and the design of clinical animal and human trials will maximize the potential benefits of these extracts in subjects suffering from periodontitis or diabetes.