A micelle nucleation model for the interaction of dodecyl sulphate with Lys49-phospholipases A(2)

Bothropstoxin-I (BthTx-I) is a Lys49-PLA(2) from the venom of Bothrops jararacussu that lacks detectable catalytic activity, yet causes rapid Ca2+-independent membrane damage. With the aim of understanding the interaction between BthTx-I and amphiphilic molecules, we have studied the interaction of sodium dodecyl sulphate (SDS) with the protein. Circular dichroism and attenuated total reflection Fourier-transform infrared spectra of BthTx-I reveal changes in the alpha-helical organization of the protein at an SDS/BthTx-I molar ratio of 20-25. At SDS/BthTx-I ratios of 40-45 the alpha-helices return to a native-like conformation, although fluorescence emission anisotropy measurements of 2-amino-N-hexadecyl-benzamide (AHBA) demonstrate that the total SDS is below the critical micelle concentration when this transition occurs. These results may be interpreted as the result of SDS accumulation by the BthTx-I homodimer and the formation of a pre-micelle SDS/BthTx-I complex, which may subsequently be released from the protein surface as a free micelle. Similar changes in the alpha-helical organization of BthTx-I were observed in the presence of dipalmitoylphosphatidylcholine liposomes, suggesting that protein structure transitions coupled to organization changes of bound amphiphiles may play a role in the Ca2+-independent membrane damage by Lys49-PLA(2)s. (c) 2006 Elsevier B.V. All rights reserved.

Positronium scattering by atoms and molecules at low energies

The recent theoretical and experimental activities in positronium (Ps) scattering by atoms and molecules are reviewed with special emphasis at low energies. We critically compare the results of different groups - theoretical and experimental. The theoretical approaches considered include the R-matrix and close-coupling methods applied to Ps-H, Ps-He and Ps-Li scattering, and a coupled-channel approach with a nonlocal model potential for Ps scattering by H, He, H-2, Ne, Ar, Li, Na, K, Rb, Cs and Ps and for pickoff quenching in Ps-He scattering. Results for scattering lengths, partial. total and differential cross-sections as well as resonance and binding energies in different systems are discussed. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Crystal Structure Determination of Mebendazole Form A Using High-Resolution Synchrotron X-Ray Powder Diffraction Data

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Spectroscopy properties and energy level location of Gd(2)O(2)S:Pr(3+),Ce(3+)

In this work we propose the study of the spectroscopy properties and the energy level location of Ce(3+) and Pr(3+) in Gd(2)O(2)S, along with the effects of Ce(4+) (Ce(2)O(2)S(2)) incorporation in Gd(2)O(2)S and Gd(2)O(2)S: Pr(3+) in order to understand the formation and position of the associated defects energy levels in relation to the band structure of Gd(2)O(2)S and Pr(3+) energy levels. Ce-, Pr(3+)-doped and Pr(3+), Ce-doped Gd(2)O(2)S were prepared by the sulfidization of a basic gadolinium carbonate with S(8) using H(2)/N(2) (3.0/97.0%) and air during the firing of the precursor. Samples were analyzed by X-ray diffraction in order to guarantee the formation of the Gd(2)O(2)S single phase. Diffuse reflectance spectroscopy and luminescent measurements (emission/excitation) were used to locate Ce(3+), Pr(3+) and defects energy levels in relation to the band structure of Gd(2)O(2)S. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Erbium-activated silica-zirconia planar waveguides prepared by sol-gel route

Er(3+) doped (100-x)SiO(2)-xZrO(2) planar waveguides were prepared by the sol-gel route, with x ranging from 10 up to 30 mol%. Multilayer films doped with 0.3 mol% Er(3+) ions were deposited on fused quartz substrates by the dip-coating technique. The thickness and refractive index were measured by m-line spectroscopy at different wavelengths. The fabrication protocol was optimized in order to confine one propagating mode at 1.5 mu m. Photoluminescence in the near and visible region indicated a crystalline local environment for the Er(3+) ion. (c) 2007 Elsevier B.V. All rights reserved.

Aspectos biológicos de Coccidophilus citricola Brèthes, 1905 (Coleoptera: Coccinellidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

First-order decay models to describe soil C-CO2 Loss after rotary tillage

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Energy transfer between Tm3+ and Er3+ ions in a TeO2-based glass pumped at diode laser wavelength

In this paper we investigate the energy transfer processes in TM3+/Er3+ doped telluride glass pumped at the commercial diode laser pump wavelength similar to 800 nm. Tailoring the rare-earths content in the glass matrix, seven main energy transfer channels within the doping range considered were identified, A 6-fold enhancement of the Er3+ visible frequency upconversion fluorescence at similar to 660 nm is observed due to the inclusion of Tm3+ ions. This is evidence of the relevant contribution of the route Er-1(I-4(11/2)) + Er-2(I-4(13/2)) -> Er-1(I-4(15/2)) + Er-2(F-4(9/2)) to the process. Energy migration among pumped I-4(9/2) level reducing the efficiency of the upconversion emission rate (H-3(11/2), S-4(3/2), and F-4(9/2)) is observed for Er3+ above 1.5 wt%. The rate equations regarding the observed energy transfer routes are determined and a qualitative analysis of the observed processes is reported. (c) 2006 Elsevier B.V. All rights reserved.

Shiitake (Lentinula edodes (Berkeley) Pegler) extracts as a modulator of micronuclei induced in HEp-2 cells

Shiitake (Lentinula edodes (Berkeley) Pegler) is one of the most consumed mushrooms, for both therapeutic purposes and as food, therefore, the study of its biological properties is of great interest for producers and consumers. Aqueous extracts of the shiitake mushroom (L. edodes (Berkeley) Pegler) were evaluated by the micronucleus test (MN) in HEp-2 cells in vitro, to analyze their possible mutagenic and antimutagenic activities. None of the three extract concentrations tested (0.5, 1.0 and 1.5 mg/mL) presented mutagenicity at any of the preparation temperatures (4 degrees C, 22 +/- 2 degrees C and 60 degrees C). In the antimutagenicity evaluation, all extract concentrations at all preparation temperatures presented a strong protective activity for the HEp-2 cells in response to the alkylating agent methyl methanesulfonate (MMS) in the different treatment protocols: pre-treatment, simultaneous treatment and post-treatment. The extracts prepared at 22 +/- 2 degrees C presented the lowest frequencies of MN in the evaluations of mutagenicity and antimutagenicity, indicating these as the best option for potential therapeutic use. (c) 2006 Elsevier Ltd. All rights reserved.

Methyl- and phenylmercury(II) derivatives of 2-mercaptobenzothiazole. Crystal structure of (2-mercaptobenzothiazolato)methylmercury(II)

The complexes MeHgL and PhHgL (HL = 2-mercaptobenzothiazole) have been obtained from the reaction of the ligand with methylmercury hydroxide and phenylmercury acetate, respectively, in methanol. MeHgL, which has been characterized by single-crystal X-ray diffraction analysis (crystal data: triclinic, space group P1, with a = 8.009 (4) Å, b = 10.042 (4) Å, c = 13.074 (3) Å, α = 101.25 (2)°, β = 102.61(3)°, γ = 101.42 (3)°, R = 0.067), crystallizes with two independent molecules, I and I′, contained in each asymmetric unit with a coordination geometry based on the almost linear C-Hg-S group (Hg-S = 2.369 (6) Å, Hg-C = 2.06 (2) Å, and C-Hg-S = 177.7 (7)° for I; Hg-S = 2.375 (6) Å, Hg-C = 2.10 (3) Å, and C-Hg-S = 178.8 (6)° for I′). A secondary intramolecular interaction between the mercury atom and the C=N group of the ring and some weak intermolecular interactions between the metal and sulfur atoms were also found. The vibrational spectra of this compound and the phenylmercury(II) compound are discussed in light of the crystal structure. Diagnostic criteria of the bonding modes for the ligand are assessed. © 1985 American Chemical Society.

Pancreatic β-cell defects in women at risk of type 2 diabetes

We evaluated insulin release and insulin sensitivity in women with basal and/or postprandial hyperglycemia but normal oral glucose tolerance test (OGTT) in previous pregnancy (GHG). These women were individually matched with females without previous hyperglycemia (NGT). Both groups consisted of normal glucose-tolerant women at the time of this study. They underwent OGTT (75g; n= 32 pairs) and hyperglycemic clamp experiments (10mmoll-1; n=27 pairs) with plasma glucose, insulin, and C-peptide measurements and calculation of insulinogenic index, first- and second-phase insulin release, and insulin sensitivity index (ISI). The GHG group showed higher glycosylated hemoglobin levels (6.2±0.6% versus 5.8±0.8%; P<0.05); lower insulinogenic index at 30min (134.03±62.69pmolmmol-1 versus 181.59±70.26pmolmmoll-1; P<0.05) and diminished C-peptide response in relation to glucose (4.05±0.36nmolmmol-1 versus 4.23±0.36nmolmmol-1; P<0.05) at OGTT. Both groups did not show difference in insulin secretion and ISI by hyperglycemic clamp technique. We concluded that in up to 12 years from index pregnancy, women with previous GHG, presenting normal glucose tolerance and well-matched with their controls, showed β-cell dysfunction without change in ISI. As women with previous GHG are at risk of type 2 diabetes, β-cell dysfunction may be its primary defect. © 2003 Elsevier B.V. All rights reserved.

Polarization of Σ+ hyperons produced by 800 GeV/c protons on Cu and Be

We show that Σ+ hyperons produced by 800 GeV/c protons on targets of Be and Cu have significant polarizations (15-20%). These polarizations persist at values of pt = 2 GeV/c and a wide range of xF. The polarizations from the Cu target are consistently less than from Be. The average ratio of the Σ+ polarization from Cu to that from Be is 0.68 ± 0.08.

Tamoxifen inhibits transforming growth factor-α gene expression in human breast carcinoma samples treated with triiodothyronine

Objectives: To examine the effects of triiodothyronine (T3), 17β-estradiol (E2), and tamoxifen (TAM) on transforming growth factor (TGF)-α gene expression in primary breast cancer cell cultures and interactions between the different treatments. Methods and results: Patients included in the study (no.=12) had been newly diagnosed with breast cancer. Fresh human breast carcinoma tissue was cut into 0.3-mm slices. These slices were placed in six 35-mm dishes on 2-ml organ culture medium. Dishes received the following treatments: dish 1: ethanol; dish 2: T3; dish 3: T3+TAM; dish 4: TAM; dish 5: E2; dish 6: E2+TAM. TGF-α mRNA content was normalized to glyceraldehyde-3-phosphate dehydrogenase mRNA levels. All tissues included in this study were positive for estrogen receptor (ER) and thyroid hormone receptor expression. Treatment with T3 for 48 h significantly increased TGF-α mRNA levels compared to controls (15-fold), and concomitant treatment with TAM reduced expression to 3.4-fold compared to controls. When only TAM was added to the culture medium, TGF-α mRNA expression increased 5.3-fold, significantly higher than with all other treatment modalities. Conclusion: We demonstrate that TGF-α mRNA expression is more efficiently upregulated by T3 than E2. Concomitant treatment with TAM had a mitigating effect on the T3 effect, while E2 induced TGF-α upregulation. Our findings show some similarities between primary culture and breast cancer cell lines, but also some important differences: a) induction of TGF-α, a mitogenic protein, by TAM; b) a differential effect of TAM that may depend on relative expression of ER α and β; and c) supraphysiological doses of T3 may induce mitogenic signals in breast cancer tissue under conditions of low circulating E2. ©2008, Editrice Kurtis.

Micropropagação de Salvia officinalis L. com avaliação do teor de fenóis totais e atividade antioxidante

Stem cuts and seeds of Salvia officinalis were incubated on nutrient media for plantlets production and analysis of the total phenolic compounds, total flanovoids and antioxidant activity in micropropagated plants. Explants were obtained from seedlings and inoculated on MS with different concentrations of benzylaminopurine (BAP) and indolbutyric acid (IBA). After 30 and 60 days of incubation, the explants were scored for percentage of contaminated, dead and oxidized explants and mean bud numbers. For bud formation, the most efficient treatment was the medium containing BAP at 1 mg L-1, for the plantlet height the better medium was the control without the addition of plant regulator. IBA promoted the formation of few roots. Our results indicated that stem cuts incubated on media containing BAP and/or IBA did not increase the total flavonoid contents, but increased the total phenolics' by BAP and high antioxidant activity by 1 mg L-1 BAP.

Measurement of the charge ratio of atmospheric muons with the CMS detector

We present a measurement of the ratio of positive to negative muon fluxes from cosmic ray interactions in the atmosphere, using data collected by the CMS detector both at ground level and in the underground experimental cavern at the CERN LHC. Muons were detected in the momentum range from 5 GeV/. c to 1 TeV/. c. The surface flux ratio is measured to be 1.2766±0.0032(stat.)±0.0032(syst.), independent of the muon momentum, below 100 GeV/. c. This is the most precise measurement to date. At higher momenta the data are consistent with an increase of the charge ratio, in agreement with cosmic ray shower models and compatible with previous measurements by deep-underground experiments. © 2010.