An in silico expert system for the identification of eye irritants

This report describes development of an in silico, expert rule-based method for the classification of chemicals into irritants or non-irritants to eye, as defined by the Draize test. This method was developed to screen data-poor cosmetic ingredient chemicals for eye irritancy potential, which is based upon exclusion rules of five physicochemical properties – molecular weight (MW), hydrophobicity (log P), number of hydrogen bond donors (HBD), number of hydrogen bond acceptors (HBA) and polarizability (Pol). These rules were developed using the ADMET Predictor software and a dataset of 917 eye irritant chemicals. The dataset was divided into 826 (90%) chemicals used for training set and 91 (10%) chemicals used for external validation set (every 10th chemical sorted by molecular weight). The sensitivity of these rules for the training and validation sets was 72.3% and 71.4%, respectively. These rules were also validated for their specificity using an external validation set of 2011 non-irritant chemicals to the eye. The specificity for this validation set was revealed as 77.3%. This method facilitates rapid screening and prioritization of data poor chemicals that are unlikely to be tested for eye irritancy in the Draize test.     

Synthesis of Carbonyl Compounds from Alcohols Using Electrochemically Generated Superoxide Ions in RTILs

Abstract

We show that the superoxide ion (O₂ ^??) generated electrochemically from oxygen dissolved in room-temperature ionic liquids (RTILs) reacts with primary and secondary alcohols to form the corresponding ketones and carboxylic acids, respectively. Specifically, we study the conversion of benzhydrol to benzophenone and benzyl alcohol to benzaldehyde/benzoic acid. The kinetics (e.g., rate, selectivity, and yield) for these reactions are also determined as functions of the variations in the structure of the ionic liquids. The RTILs used here are imidazolium-based cations where the functional groups on the imidazolium ring are modified. Specifically, 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF₆], 1-butyl-2,3-dimethylimidazolium hexafluorophosphate [bdmim][PF₆], and 1-hexyl-3-methylimidazolium hexafluorophosphate [hmim][PF₆] are used as the reaction medium. These results are compared to an ammonium-based RTIL (N-butyl-N-trimethylammonium bis(trifluoromethylsulfonyl)imide). The results show that the nucleophilic attack by the O₂ ^?? of both the RTIL and the alcohol, especially that of the H atom at the R2 position of the [bmim][PF₆] and [hmim][PF₆], greatly affects the yields. No RTIL degradation products were detected for the reactions in [bdmim][PF₆] and N-butyl-N-trimethylammonium bis(trifluoromethylsulfonyl)imide ionic liquids. For the benzyl alcohol oxidation reaction in the RTIL, N-butyl-N-trimethylammonium bis(trifluoromethylsulfonyl)imide, benzaldehyde formed did not undergo further oxidation to form benzoic acid, which may be due to the greater hydrophobicity of this RTIL. The competitive reaction kinetics between the alcohol and RTIL component must be considered in the selection of the RTIL solvent system.     

High-resolution in vivo imaging of blood vessels without labeling

We demonstrate that both oxyhemoglobin and deoxyhemoglobin have sequential two-color, two-photon absorption properties that can serve as endogenous contrasts in microvasculature imaging. Using a sensitive modulation transfer technique, we are able to image hemoglobin in red blood cells with micrometer resolution, both in vitro and in vivo. We show that excellent contrast from hemoglobin without any labeling can be obtained in tissue.     

Surface activity and self-aggregation ability of three cationic quaternized aminocalix[4]arenes

The self-aggregation ability of three amphiphilic cationic calix[4]arenes possessing four quaternary amino groups (aminoCAs) was investigated using a variety of methods. All of the studied compounds possess high aggregation ability. Their critical aggregation concentration (CAC) values in water are in the 0.0009–0.04 % (w/v) concentration range. Several size populations of aggregates were detected by DLS for all three CAs, and restructuring of aggregates was observed to be dependent on concentration. Particles formed above CAC were attributed to formation of vesicular structures (vesicles). The coexistence of other type of aggregates (presumably micelles) with vesicles was observed in the aqueous solution of CAs 2 and 3 from concentrations of 0.5 and 0.8 % (w/v), respectively. The filtration procedure was found to be a significant factor since the obtained data from filtered and unfiltered samples was different. The particle sizes obtained by TEM measurements were somewhat correlated with the DLS data for unfiltered CAs solutions. An analysis of the aggregate composition was undertaken by a size-exclusion method using semi-permeable cellophane membranes with different MWCO. A negative deviation from linearity of permeability flux profile starting from 0.8 % (w/v) concentration of donor phase indicated that the fraction of large aggregates at this point is significant enough that the molecules could not easily permeate through the membranes.     

Characterization of the raw essential oil eugenol extracted from <Emphasis Type="Italic">Syzygium</Emphasis> <Emphasis Type="Italic">aromaticum</Emphasis> L.

Eugenol is the main volatile compound extracted oil from clove bud, Syzygium aromaticum L., and used in traditional medicine, as a bactericide, fungicide, anesthetic, and others. Its extraction was performed using hydrodistillation which is the most common extraction technique. Its components and thermal behavior were evaluated using gas chromatography (GC) and differential scanning calorimetry (DSC), which provide a better characterization of these natural compounds. This extracted product was compared to the standard eugenol results. The GC results suggested ~90% eugenol was found in the total extracted oil, and some of its boiling characteristics were 270.1 °C for peak temperature and 244.1 J g⁻¹ for the enthalpy variation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Study of K−p→K1(890)n at 13 GeV

The results of a wire chamber spectrometer experiment studying $\text{K}$¹ (890) production in the reaction K^?p→ K^?π⁺n at 13 GeV are presented. Strong forward structure is observed for |t|< m²_π in the s-channel density matrix elements and differential cross section. These features are similar to those observed in π^?p→?⁰n data and are characteristics of π exchange. In contrast in the intermediate, |t| ～ 0.2 GeV², and large momentum transfer regions $\text{K}$¹ (890) production is demonstrated by the natural parity ??A₂ exchange contribution.     

The two-body photodisintegration of 3He

The differential cross section for the reaction ³He(γ,d)¹¹H has been measured for proton energies 11–65 MeV. The results are compared with previous measurements and with a recent theoretical calculation.     

Least squares method for analyzing broadened x-ray line shapes

A method for obtaining values of the widths and other parameters describing the Gaussian and Lorentzian components of peaks, which have the shape of the convolution of those functions, is described. Results of the method are given for X-ray data containing several peaks with different ratios of the composite widths in separate spectra.     

Studies in qualitative inorganic analysis. Part XLI

Summary The solubility of mercury(II) sulphide in the various reagents used to separate the copper-tin group has been quantitatively investigated. Our results show that with all reagents the solubility of mercury(II) sulphide is largest when tin(IV) and molybdenum(VI) are present and that the use of hydrogen peroxide with potassium hydroxide ensures that at least 95% of the mercury appears in the copper group.

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Zusammenfassung Die Löslichkeit von Queoksilber(II)-sulfid in den verschiedenen, zur Trennung der Kupfer-Zinn-Gruppe verwendeten Reagenzien wurde quantitativ überprüft. Diese Löslichkeit ist dann in allen Reagenzien am größten, wenn Zinn(IV) und Molybdän(VI) zugegen sind. Die Anwendung von Wasserstoffperoxid und Kalilauge gibt die Gewähr, daß mindestens 95% des Quecksilbers in der Kupfergruppe zu finden sind.

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Part XL: Mikrochim. Acta [Wien] 1970, 83.