Fluorescence Detection of the Ornamental Fish Cardinal Tetra (Paracheirodon axelrodi)

The fluorescence spectra of the tropical fish, Cardinal Tetra ( Paracheirodon axelrodi ), originating in the Amazon region of Brazil, were determined. These spectra were then treated using factor analysis, generating two contributing spectra and separating out the noise. Time-resolved fluorescence results indicated that the fluorescent system in the epidermis undergoes excited state reaction. Excited state proton transfer is suggested as being present. Both intentionally stressed and nonstressed individuals were used and some small differences were noted in the contributions of the two calculated contributing spectra to the experimental spectra, presumably as a function of stress. The results are compared with those obtained by the standard determination of cortisol level using the whole body extraction method and it is suggested that the method could be tested as an improved, nondestructive way to determine stress in this species, which is a necessary step in the development of "best management practices" of methods for storage and transport of the fish.     

A coupling cutting stock-lot sizing problem in the paper industry

An important production programming problem arises in paper industries coupling multiple machine scheduling with cutting stocks. Concerning machine scheduling: how can the production of the quantity of large rolls of paper of different types be determined. These rolls are cut to meet demand of items. Scheduling that minimizes setups and production costs may produce rolls which may increase waste in the cutting process. On the other hand, the best number of rolls in the point of view of minimizing waste may lead to high setup costs. In this paper, coupled modeling and heuristic methods are proposed. Computational experiments are presented.     

Solvent and temperature effects on the conformational equilibria of a dihydrobenzo[h]quinolinium fluoroborate

Spectra of the N‐phenyl‐5,6‐dihydro‐2,4‐diphenylbenzo[h]quinolinium tetrafluoroborate (1) and of the N‐phenyl‐5,6,8,9‐tetrahydro‐7‐phenyldibenzo[c,h]acridinium tetrafluoroborate (2) were recorded in various solvents and temperatures. The analysis of the ¹H‐NMR spectra of the tetrafluoroborate salt 1, recorded in acetone, acetonitrile, 1,1,2,2‐tetrachloroethane and chloroform, revealed the existence of an equilibrium between two conformers in solution. Tight ion‐pairing in chloroform led to a smaller barrier for interconversion between the two conformers. In more polar solvents, where the dihydrobenzoquinolinium exists as a free cation, theoretical calculations predicted larger barriers. The spectra of 1 in 1,1,2,2‐tetrachloroethane also varied with temperature, resembling at higher temperatures the spectrum in CDCl₃ and at 300K spectra in more polar media. Spectra of 2 did not vary with the solvent or the temperature, in an indication of a much higher barrier to conformational interconversion, because of a greater steric hindrance between the N‐phenyl substituent and the dihydrobenzo rings. Copyright © 2009 John Wiley & Sons, Ltd.     

4-Trichloroacetyl-1,2,3-triazoles: A versatile building block for rapid assessment of carbohydrazides and rufinamide derivatives

This work reports the synthesis of a series of (1H-1,2,3-triazol-4-yl)carbohydrazides (2), which were obtained from 4-trichloroacetyl-1H-1,2,3-triazoles (1). Triazoles 1 were synthesized by 1,3-dipolar cycloaddition reaction, starting from 4-alkoxy-1,1,1-trichloroalk-3-en-2-ones and benzyl azides and easily (15 min) converted to 2 by reaction with hydrazine hydrate (73–82% yield). Carbohydrazides 2 proved to be a versatile building block for constructing a series of fluorinated heterocycles analogous to rufinamide, i.e., 1H-1,2,3-triazol-4-yl-1,3,4-oxadiazoles, a pyrrole derivative, and a 2-pyrazoline, through [4+1]–, [1+4]–, and [3+2]–cyclocondensation reactions, respectively. Finally, and according to the Lipinski’s rule of five, 2,6-difluorobenzylated 1,2,3-triazoles can be considered as potential candidates for further biological activity assays.     

New,simple, and efficient method for the synthesis of N-substituted 4-trifluoromethyl-5-(alkan-1-ol)-pyridin-2(1H)-imines

A new, simple, and efficient method for the synthesis a novel series of 1-substituted 4-(trifluoromethyl)-5-(alkan-1-ol)-pyridin-2(1H)-imines from the reaction of 3-(5,6-dihydro-4H-pyran-3-yl)-4,4,4-trifluorobut-2-enenitrile and 3-(4,5-dihydrofuran-3-yl)-4,4,4-trifluorobut-2-enenitrile with primary amines – is described. The products were obtained in 29–82% yield.     

Photocatalytic behavior of α-Bi2Mo3O12 prepared by the Pechini method: degradation of organic dyes under visible-light irradiation

Nanoparticles of α-Bi₂Mo₃O₁₂ were prepared by the Pechini method. The process of formation of the bismuth molybdate was followed by simultaneous thermogravimetric and differential thermal analysis (TGA/DTA). Different samples of α-Bi₂Mo₃O₁₂ were obtained at 400, 450, and 500 °C, and characterized by X-ray powder diffraction (XRD), nitrogen physisorption (BET), and scanning electron microscopy (SEM). When observed by SEM, the morphology of the sample obtained at the lowest temperature consisted of semi-spherical particles with an average diameter of 150 nm. On the other hand, the highest calcination temperature led to the formation of sintered particles of 500–600 nm. The photocatalytic activity of α-Bi₂Mo₃O₁₂ was tested by photodegradation of the organic dyes rhodamine B (rhB) and indigo carmine (IC) under visible-light irradiation. The bismuth molybdate nanoparticles were able to bleach aqueous solutions of both organic dyes. The sample obtained at 400 °C was the best photocatalyst with half-lives, t _1/2, of 108 and 154 min for rhB and IC, respectively.     

Porous nanocomposite hydrogel of vinyled montmorillonite-crosslinked maltodextrin-co-dimethylacrylamide as a highly stable polymer carrier for controlled release systems

Nanocomposite hydrogel consisting of dispersed montmorillonite-crosslinked maltodextrin-co-dimethylacrylamide (malt-dex-co-DMAAm) as a highly stable device was developed. Carbon-carbon π-bonds issued from glycidyl methacrylate (GMA) were incorporated onto both the MMT (MMT-π) and the malt-dex (malt-dex-π) structures. The nanocomposite copolymer hydrogel was processed via radical crosslinking reaction of malt-dex-π with MMT-π in the presence of DMAAm. The radical reaction of the carbon-carbon π-bonds at the MMT-π was verified by treating the MMT-π with sodium persulfate. There was an excellent dispersion of the MMT-π at the interior of the matrix even after the nanocomposite hydrogel being swollen, demonstrating that the developed methodology can imprint stability of mineral nanoparticles into a porous polymer network preventing diffusion of water-bonded silicate platelets toward the outside matrix. The water absorption profile became more dependent on the polymer relaxation for mineral-loader nanocomposite hydrogels. Higher water absorption had an impact on reduction of elasticity modulus due to softer polymer network in swollen state.     

Phase behaviour of binary systems of lactones in carbon dioxide

Experimental phase equilibrium data for binary systems involving ε-caprolactone, δ-hexalactone, and γ-caprolactone with carbon dioxide have been measured applying the synthetic method using a high-pressure, variable-volume view cell over the temperature range of (303 to 343) K and pressures up to 21 MPa. For the systems investigated, (vapour + liquid) (VLE), (liquid + liquid) (LLE), and (vapour + liquid + liquid) (VLLE) equilibrium were visually recorded. It was observed that an increase in temperature or in carbon dioxide concentration led to a pronounced raise in transition pressure values. The experimental results were modelled using the Peng–Robinson equation of state with the conventional quadratic mixing rule, affording a satisfactory representation of the experimental values.     

Phase behaviour of the ternary system {poly(ε-caprolactone) + carbon dioxide + dichloromethane}

Recently, production of biocompatible and biodegradable polymer microparticles has been a matter of growing interest in pharmaceutical and food areas such as drug or active compounds delivery. To conduct production of microparticles, polymeric particle coating, impregnation of active compounds in polymeric films, the knowledge of phase behaviour involving the biodegradable polymer in supercritical carbon dioxide in the presence of a modifier may be needed to allow developing new industrial applications. In this sense, the aim of this work was to investigate the phase behaviour of the ternary system formed by the biodegradable polymer poly(ε-caprolactone) in (carbon dioxide + dichloromethane). Experimental phase transition (bubble and cloud point) values were obtained by applying the static-synthetic method using a variable-volume view cell over the temperature range of (303 to 343) K and pressures up to 21 MPa, in the CO₂ overall composition range of (25–46) wt%, while polymer concentrations studied were (1, 3, 5, and 7) wt%. For the system investigated, depending on the polymer concentration, vapour–liquid, liquid–liquid, and vapour–liquid–liquid phase transitions were verified.