BVRI Light Curves for 29 Type Ia Supernovae

BVRI light curves are presented for 27 Type Ia supernovae discovered during the course of the Calan/Tololo Survey and for two other SNe Ia observed during the same period. Estimates of the maximum light magnitudes in the B, V, and I bands and the initial decline rate parameter m15(B) are also given.Comment: 17 pages, figures and tables are not included (contact first author if needed), to appear in the Astronomical Journa

Nanometric Particle Size And Phase Controlled Synthesis And Characterization Of γ-fe2o3 Or (α + γ)-fe2o3 By A Modified Sol-gel Method

Fe2O3 nanoparticles with sizes ranging from 15 to 53 nm were synthesized by a modified sol-gel method. Maghemite particles as well as particles with admixture of maghemite and hematite were obtained and characterized by XRD, FTIR, UV-Vis photoacoustic and Mössbauer spectroscopy, TEM, and magnetic measurements. The size and hematite/maghemite ratio of the nanoparticles were controlled by changing the Fe:PVA (poly (vinyl alcohol)) monomeric unit ratio used in the medium reaction (1:6, 1:12, 1:18, and 1:24). The average size of the nanoparticles decreases, and the maghemite content increases with increasing PVA amount until 1:18 ratio. The maghemite and hematite nanoparticles showed cubic and hexagonal morphology, respectively. Direct band gap energy were 1.77 and 1.91 eV for A6 and A18 samples. Zero-field-cooling-field-cooling curves show that samples present superparamagnetic behavior. Maghemite-hematite phase transition and hematite Néel transition were observed near 700 K and 1015 K, respectively. Magnetization of the particles increases consistently with the increase in the amount of PVA used in the synthesis. Mössbauer spectra were adjusted with a hematite sextet and maghemite distribution for A6, A12, and A24 and with maghemite distribution for A18, in agreement with XRD results. © 2013 AIP Publishing LLC.11410Xu, P., Zeng, G.M., Huang, D.L., Feng, C.L., Hu, S., Zhao, M.H., Lai, C., Liu, Z.F., (2012) Sci. Total Environ., 424, pp. 1-10. , 10.1016/j.scitotenv.2012.02.023Rajabi, F., Karimi, N., Saidi, M.R., Primo, A., Varma, R.S., Luque, R., (2012) Adv. Synth. Catal., 354, pp. 1707-1711. , 10.1002/adsc.201100630Kitamuraa, H., Zhaob, L., Hangc, B.T., Okadab, S., Yamaki, J.-I., (2012) J. Power Sources, 208, pp. 391-396. , 10.1016/j.jpowsour.2012.02.051Figuerola, A., Di Corato, R., Manna, L., Pellegrino, T., (2010) Pharmacol. 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Spectroscopic Observations of Some S-Type Symbiotic Stars

Observations of a group of S-type symbiotic stars are presented : Hen 828, Hen 905, Hen 1103, Hen 1213, KX TrA (Cn 1-2), AE Ara (PC 18), AS 255, AS 270, AS 289, Y CrA, AS 304, AS 316, AS 327, and CD [43¡14304. The observations were made in three di erent epochs of observation : 1987, 1991, and 1995, except for Y CrA, which was observed in 1990. Several parameters are obtained for each object : spectral types of the late components; distances derived from these spectral types ; interstellar reddening as determined from the Balmer decrement, considering optical depth e ects ; electron temperatures and densities ; helium abundances, also determined considering optical depth e ects ; and characteristics of the hot components. It has been found that Hen 828 and Hen 1103 were possibly having an outburst in 1991; the same could be true for AS 270 in 1995 and CD [43¡14304 in 1991. Another interesting object is Hen 905, which is surrounded by a nebulosity that could be a ring, reaching a distance of about 2@, with emission mainly in Ha and O VI j6825

Osmocentrifugation In Density Gradients: Application To Polymer Latex Separation.

Polymer latexes can be fractionated by size and by chemical composition through osmocentrifugation. Density gradients are formed by centrifuging Ficoll and Percoll solutions in dialysis cells; mixed polymer latex zones are layered over these gradients and centrifuged again, leading to separated latex bands from which polymer may be collected and further analyzed. Zone migration rates in the osmocentrifugation experiment are faster than in standard centrifugation tubes.34285386

Extraction, structural modification and characterization of lotus roots polysaccharides (Nelumbo nucifera Gaertn)

Debido a su biodegradabilidad, recientemente los polisacáridos han sido bastante estudiados para su utilización en sistemas de liberación controlada de farmacos, ya que ellos pueden ser degradados específicamente por la flora bacteriana intestinal. Sin embargo, como regla general los polisacáridos son muy solubles en agua causando una rápida desintegración del revestimiento y liberación precoz del medicamento. Entretanto, estos polí- meros pueden ser fácilmente modificados por el proceso químico de entrecruzamiento (reticulación). En este estudio, polisacáridos de raíz de lotus (Nelumbo nucifera) fueron reticulados con trimetafosfato de sodio (TMPS) por una reacción de fosfatación involucrando los grupos hidrofílicos (hidroxilos) de la molécula, disminuyendo de esta forma su solubilidad en agua y por lo tanto atrasando la liberación del medicamento para las porciones dístales del intestino grueso y delgado. La reacción de reticulación fue confirmada con base en espectros de FTIR, donde la banda de hidroxilos mostró alteración después de la modificación química y también surgió una banda característica de enlace P-O-C. Los análisis térmicos ralizados también son descritos: Análisis termogravimétrico (TGA) y Calorimetría Diferencial de Barrido (DSC).Due to its biodegradability, lastly polysaccharides have been largely studied for utilization in controlled drug release systems, since they can be specifically degraded by the intestinal bacterial flora. However, as a general rule polysaccharides are very hydrosoluble, causing a fast coating disintegration and precocious drug liberation. Nevertheless, these polysaccharides can be easily modified by chemical processes, like the cross-linking reaction. In this study, lotus (Nelumbo nucifera) root polysaccharides were cross-linked with trisodium trimetaphosphate (TSMP) through a phosphatation reaction involving the hydrophilic groups (hydroxyls) of the molecule, thus decreasing its hydrosolubility and, therefore, putting back the drug release until distal portions of the small and large bowel. Cross-linking reaction confirmation was based in Fourier Transformed Infrared Spectroscopy (FT-IR) analyses, where hydroxyls band showed alteration after chemical modification and a characteristic band of the P-O-C linkage emerged. Thermal analysis (Thermogravimetric Analysis, TGA and Differential Scanning Calorimetry, DSC) were also performedColegio de Farmacéuticos de la Provincia de Buenos Aire

Thermal and photochemical stability of poly(vinyl alcohol)/modified lignin blends

A kraft lignin derivative (KLD) obtained by reaction with p-aminobenzoic acid/phthalic anhydride was blended with poly(vinyl alcohol) (PVA) by solution casting from DMSO. PVA and PVA/KLD films were exposed to ultraviolet radiation (24, 48, and 96 h) and analyzed by thermogravimetry (TG), differential scanning calorimetry (DSC), infrared spectroscopy (FTIR), hydrogen nuclear magnetic resonance (H-1 NMR) spectroscopy, and scanning electron microscopy (SEM). PVA films show a loss of thermal stability due to irradiation. PVA/KLD reveals greater thermal stability than PVA and an increase in thermal stability after irradiation. These results suggest that the incorporation of KLD into PVA provides a gain in thermal and photochemical stability. FTIR, H-1 NMR, DSC, and TG results obtained for the blends suggest that intermolecular interactions between PVA and KLD chains are present. SEM micrographs revealed blend miscibility for a KLD blend content of up to 15 wt%, as observed at magnification of 1000 times. (c) 2005 Elsevier Ltd. All rights reserved

Free films containing acrylic polymer and B-cyclodextrin as potential material for colonic delivery: permeability, swelling property, and physicochemical analyses

This work evaluated the influence of B-cyclodextrin (B-CD) on Eudragit® FS 30 D (FS) free film-forming capacity in the following blends: 90:10 and 95:5 (FS: B-CD) as material for potential application in colonic drug delivery systems. A control film (FS 100 %) was also prepared. Determination of swelling index (Is%) and permeability and physicochemical analysis were carried out. Formulations containing 95:5 or 90:10 FS: B-CD ratio and about 5 % of glyceryl monostearate (GMS) as a glidant provided homogeneous, continuous, and flexible films. Water vapour transmission (WVT) increased with an increase in B-CD concentration. On the other hand, how major was the B-CD amount lower was found the Is% for the film. Physicochemical analysis using TG revealed an initial thermal decomposition temperature shift that indicated lower thermal stability for films with 90:10 or 95:5 FS: B-CD ratio compared with the control (100:0). The results of FT-IR did not give evidence of any intermolecular interaction between B-CD and the acrylic polymer, showing just a physical mixture of both components in formulation.Colegio de Farmacéuticos de la Provincia de Buenos Aire