Scalar resonances in a unitary pi pi S-wave model for D(+)->pi(+)pi(-)pi(+)

We propose a model for D(+)->pi(+)pi(-)pi(+) decays following experimental results which indicate that the two-pion interaction in the S wave is dominated by the scalar resonances f(0)(600)/sigma and f(0)(980). The weak decay amplitude for D(+)-> R pi(+), where R is a resonance that subsequently decays into pi(+)pi(-), is constructed in a factorization approach. In the S wave, we implement the strong decay R ->pi(+)pi(-) by means of a scalar form factor. This provides a unitary description of the pion-pion interaction in the entire kinematically allowed mass range m(pi pi)(2) from threshold to about 3 GeV(2). In order to reproduce the experimental Dalitz plot for D(+)->pi(+)pi(-)pi(+), we include contributions beyond the S wave. For the P wave, dominated by the rho(770)(0), we use a Breit-Wigner description. Higher waves are accounted for by using the usual isobar prescription for the f(2)(1270) and rho(1450)(0). The major achievement is a good reproduction of the experimental m(pi pi)(2) distribution, and of the partial as well as the total D(+)->pi(+)pi(-)pi(+) branching ratios. Our values are generally smaller than the experimental ones. We discuss this shortcoming and, as a by-product, we predict a value for the poorly known D ->sigma transition form factor at q(2)=m pi(2).

Dynamical Casimir effect for a massless scalar field between two concentric spherical shells with mixed boundary conditions

In this work we analyze the dynamical Casimir effect for a massless scalar field confined between two concentric spherical shells considering mixed boundary conditions. We thus generalize a previous result in literature [Phys. Rev. A 78, 032521 (2008)], where the same problem is approached for the field constrained to the Dirichlet-Dirichlet boundary conditions. A general expression for the average number of particle creation is deduced considering an arbitrary law of radial motion of the spherical shells. This expression is then applied to harmonic oscillations of the shells, and the number of particle production is analyzed and compared with the results previously obtained under Dirichlet-Dirichlet boundary conditions.

Dynamical Casimir effect for a massless scalar field between two concentric spherical shells

In this work we consider the dynamical Casimir effect for a massless scalar field-under Dirichlet boundary conditions-between two concentric spherical shells. We obtain a general expression for the average number of particle creation, for an arbitrary law of radial motion of the spherical shells, using two distinct methods: by computing the density operator of the system and by calculating the Bogoliubov coefficients. We apply our general expression to breathing modes: when only one of the shells oscillates and when both shells oscillate in or out of phase. Since our results were obtained in the framework of the perturbation theory, under resonant breathing modes they are restricted to a short-time approximation. We also analyze the number of particle production and compare it with the results for the case of plane geometry.

Relevance of extractives and wood transformation products on the biodegradation of Pinus taeda by Ceriporiopsis subvermispora

Ceriporiopsis subvermispora is a promising white-rot fungus for biopulping. However, the underlying biochemistry involved in lignin removal and insignificant cellulose degradation by this species is not completely understood. This paper addresses this topic focusing on the involvement of ethanol-soluble extractives and wood transformation products in the biodegradation process. Cultures containing ethanol-extracted or in natura wood chips presented similar levels of extracellular enzymes and degradation of wood components. Fe3+-reducing compounds present in undecayed Pinus taeda were rapidly diminished by fungal degradation. Lignin-degradation products released during biodegradation restored part of the Fe3+-reducing activity. However, Fe3+ reduction was ineffective in presence of 0.5 mM oxalate at pH 4.5. Fungal consumption of Fe3+-reducing compounds and secretion of oxalic acid minimized the significance of Fenton`s reaction in the initial stages of wood biotreatment. This would explain limited polysaccharide degradation by the fungus that also lacks a complete set of hydrolytic enzymes. Scientific relevance of the paper: Ceriporiopsis subvermispora is a white-rot fungus suitable for biopulping processes because it degrades lignin selectively and causes significant structural changes on the wood components during the earlier decay stages. However, the intricate mechanism to explain lignin transformation and insignificant cellulose degradation by this species remains poorly understood. Some recent evidences pointed out for lipid peroxidation reactions as all initiating process explaining lignin degradation. On the other hand, alkylitaconic acids produced by the fungus via transformations of fatty acids occurring in wood showed to prevent polysaccharide degradation in Fenton reactions. In this context, one may conclude that the involvement of native wood substances or their transformation products in the overall wood biodegradation process induced by C subvermispora is still a matter of discussion. While free and esterified fatty acids present in wood extractives may be involved in the biosynthesis of alkylitaconic acids and in lipid peroxidation reactions, some extractives and lignin degradation products can reduce Fe3+, providing Fe2+ species needed to form OH radical via Fenton`s reaction. The present study focuses on this topic by evaluating the relevance of ethanol-soluble extractives and wood transformation products on the biodegradation of P. taeda by C subvermispora. For this, solid-state cultures containing ethanol-extracted and in natura wood chips were evaluated in details for up to 4 weeks. (C) 2007 Elsevier Ltd. All rights reserved.

Chemical characterization and anticorrosion properties of corrosion products formed on pure copper in synthetic rainwater of Rio de Janeiro and Sao Paulo

This work aims to characterize corrosion products formed on copper samples exposed to synthetic rainwater of Rio Janeiro and Sao Paulo. XRD and XPS were employed to determine their composition, while electrochemical techniques were used to evaluate their protective properties. XRD and XPS indicated the thickening of the corrosion layer with time. Electrochemical results showed that the protectiveness of the corrosion layer depends on the solution composition. Based on our findings a corrosion mechanism for copper in simulated rainwater is proposed where the role of NH(4)(+) ions in the cuprite layer partial regeneration is taken into account. (C) 2009 Elsevier Ltd. All rights reserved.

Comparative physical-chemical characterization of encapsulated lipid-based isotretinoin products assessed by particle size distribution and thermal behavior analyses

Isotretinoin is the drug of choice for the management of severe recalcitrant nodular acne. Nevertheless, some of its physical-chemical properties are still poorly known. Hence, the aim of our study consisted to comparatively evaluate the particle size distribution (PSD) and characterize the thermal behavior of the three encapsulated isotretinoin products in oil suspension (one reference and two generics) commercialized in Brazil. Here, we show that the PSD, estimated by laser diffraction and by polarized light microscopy, differed between the generics and the reference product. However, the thermal behavior of the three products, determined by thermogravimetry (TGA), differential thermal (DTA) analyses and differential scanning calorimetry (DSC), displayed no significant changes and were more thermostable than the isotretinoin standard used as internal control. Thus, our study suggests that PSD analyses in isotretinoin lipid-based formulations should be routinely performed in order to improve their quality and bioavailability. (C) 2010 Elsevier B.V. All rights reserved.

Phenolic composition and antioxidant activity of culms and sugarcane (Saccharum officinarum L.) products

The present work reports amounts of flavonoids and phenylpropanoids of culms of three sugarcane varieties and of raw juice, syrup, molasse and VHP sugar. The antioxidant activity of those materials was evaluated by the DPPH and beta-carotene/linoleic acid methods. The predominant phenolics in culms were phenylpropanoids (caffeic, chlorogenic and coumaric acids), while flavones (apigenin, tricin and luteolin derivatives) appeared in lower amounts. Differences were noted either among phenolic profiles of sugarcane culms or between culms and sugarcane products. The antioxidant activities of solutions from most samples were similar or higher than a 80 mu M Trolox solution. (C) 2010 Elsevier Ltd All rights reserved.

Cannabinoid contents in cannabis products seized in Sao Paulo, Brazil, 2006-2007

A rapid and simple method was optimized for determination of Delta(9)-tetrahydrocannabinol (Delta(9)-THC), cannabidiol (CBD), and cannabinol (CBN) contents in cannabis products by gas chromatography with flame-ionization detection (GC-FID), using diazepam as internal standard. All parameters of validation of the method such as linearity, intraassay precision, and limits of detection and quantification of the analytes were satisfactory. Using the described method, cannabinoid contents of 55 cannabis product samples seized in Sao Paulo City, Brazil, in 2006 and 2007 were measured. Delta(9)-THC content in marijuana and hashish samples varied between 0.08% and 5.5%, with an average of 2.5%. The phenotypic ratio showed that the products were able to be designated as ""drug type.""

Identification of Staphylococcus aureus Carrying the mecA Gene in Ready-to-Eat Food Products Sold in Brazil

Since Staphylococcus aureus can cause several types of diseases, the development of antibiotic resistance poses an even greater threat to public health. S. aureus is known to possess the adaptive capability to promptly respond to antibiotics, making it resistant and increasingly difficult to treat; methicillin-resistant strains of S. aureus are a major concern with regard to this species. Previous studies reported the identification of methicillin-resistant S. aureus in food, demonstrating that this can represent a source of S. aureus which may carry the mecA gene. Fifty-seven S. aureus isolates, previously obtained from different types of food, were screened by polymerase chain reaction with specific primers for the mecA gene, which mediates methicillin resistance. Five (9%) isolates showed the presence of mecA gene, demonstrating that food may contain microorganisms possessing resistance genes. This study emphasizes the need to include food as a possible source of S. aureus carrying mecA gene and the need to monitor these products. Moreover, this is the first report of the presence of mecA genes in S. aureus isolated from ready-to-eat food in Brazil and Latin America.

Endophytic fungi found in association with Smallanthus sonchifolius (Asteraceae) as resourceful producers of cytotoxic bioactive natural products

Smallanthus sonchifolius is a traditional Andean plant which has been cultured mainly in Brazil, Japan and New Zealand due to its medicinal properties. A study of the endophytic fungi associated to the plant was carried out in order to characterize new cytotoxic agents. Thirty two fungal strains were isolated and submitted to cultivation and extraction producing 186 extracts. Of these, 12% displayed moderate to high cytotoxic activities and were considered promising anticancer compound sources. The ethyl acetate fractions of Nigrospora sphaerica and Phoma betae liquid fermentations contained the synergistic compounds 8-hydroxy-6-methoxy-3-methylisocoumarin and (22E,24R)-ergosta-4,6,8(14),22-tetraen-3-one which are potential compounds for drug discovery. Another isolated compound, pimara-7,15-dien-3-beta-ol diterpene is being characterized for the first time through a detailed spectroscopic analysis including GC/MS, homo- and hetero-nuclear correlated NMR experiments (HMQC, HMBC, COSY and NOEdiff) along with its optical rotation.

Development Resource Planning: Complexity of Product Development and the Capacity to Launch New Products

Overcommitment of development capacity or development resource deficiencies are important problems in new product development (NPD). Existing approaches to development resource planning have largely neglected the issue of resource magnitude required for NPD. This research aims to fill the void by developing a simple higher-level aggregate model based on an intuitive idea: The number of new product families that a firm can effectively undertake is bound by the complexity of its products or systems and the total amount of resources allocated to NPD. This study examines three manufacturing companies to verify the proposed model. The empirical results confirm the study`s initial hypothesis: The more complex the product family, the smaller the number of product families that are launched per unit of revenue. Several suggestions and implications for managing NPD resources are discussed, such as how this study`s model can establish an upper limit for the capacity to develop and launch new product families.

Demand elasticities for food products in Brazil: a two-stage budgeting system

The object of this article is to estimate demand elasticities for a basket of staple food important for providing the caloric needs of Brazilian households. These elasticities are useful in the measurement of the impact of structural reforms on poverty. A two-stage demand system was constructed, based on data from Household Expenditure Surveys (POF) produced by IBGE (The Brazilian Bureau of Statistics) in 1987/88 and 1995/96. We have used panel data to estimate the model, and have calculated income, own-price, and cross-price elasticities for eight groups of goods and services and, in the second stage, for 11 sub groups of staple food products. We estimated those elasticities for the whole sample of consumers and for two income groups.

Simultaneous analysis of parabens in cosmetic products by stir bar sorptive extraction and liquid chromatography

A sensitive and precise stir bar sorptive extraction (SBSE) combined with LC (SBSE/LC) analysis is described for simultaneous determination of methyl, ethyl, propyl, and butyl parabens in commercial cosmetic products in agreement with the European Union Cosmetics Directive 76/768/EEC. Important factors in the optimization of SB SE efficiency are discussed, such as time and temperature of extraction, pH, and ionic strength of the sample, matrix effects, and liquid desorption conditions by different modes (magnetic stirring, ultrasonic). The LOQs of the SBSE/LC method ranged from 30 to 200 ng/mg, with linear response over a dynamic range, from the LOQ to 2.5 mu g/mg, with a coefficient of determination higher than 0.993. The interday precision of the SBSE/LC method presented a coefficient of variation lower than 5%. The effectiveness of the proposed method was proven for analysis of commercial cosmetic products such as body creams, antiperspirant creams, and sunscreens.

Analysis of Intracellular Substrates and Products of Thimet Oligopeptidase in Human Embryonic Kidney 293 Cells

Thimet oligopeptidase (EC 3.4.24.15; EP24.15) is an intracellular enzyme that has been proposed to metabolize peptides within cells, thereby affecting antigen presentation and G protein-coupled receptor signal transduction. However, only a small number of intracellular substrates of EP24.15 have been reported previously. Here we have identified over 100 peptides in human embryonic kidney 293 (HEK293) cells that are derived from intracellular proteins; many but not all of these peptides are substrates or products of EP24.15. First, cellular peptides were extracted from HEK293 cells and incubated in vitro with purified EP24.15. Then the peptides were labeled with isotopic tags and analyzed by mass spectrometry to obtain quantitative data on the extent of cleavage. A related series of experiments tested the effect of overexpression of EP24.15 on the cellular levels of peptides in HEK293 cells. Finally, synthetic peptides that corresponded to 10 of the cellular peptides were incubated with purified EP24.15 in vitro, and the cleavage was monitored by high pressure liquid chromatography and mass spectrometry. Many of the EP24.15 substrates identified by these approaches are 9-11 amino acids in length, supporting the proposal that EP24.15 can function in the degradation of peptides that could be used for antigen presentation. However, EP24.15 also converts some peptides into products that are 8-10 amino acids, thus contributing to the formation of peptides for antigen presentation. In addition, the intracellular peptides described here are potential candidates to regulate protein interactions within cells.

A reassessment of the in vitro RBC haemolysis assay with defibrinated sheep blood for the determination of the ocular irritation potential of cosmetic products: Comparison with the in vivo Draize rabbit test

We examined the correlation between results obtained from the in vivo Draize test for ocular irritation and in vitro results obtained from the sheep red blood cell (RBC) haemolytic assay, which assesses haemolysis and protein denaturation in erythrocytes, induced by cosmetic products. We sought to validate the haemolytic assay as a preliminary test for identifying highly-irritative products, and also to evaluate the in vitro test as alternative assay for replacement of the in vivo test. In vitro and in vivo analyses were carried out on 19 cosmetic products, in order to correlate the lesions in the ocular structures with three in vitro parameters: (i) the extent of haemolysis (H50); (ii) the protein denaturation index (131); and (iii) the H50/DI ratio, which reflects the irritation potential (IP). There was significant correlation between maximum average scores (MAS) and the parameters determined in vitro (r = 0.752-0.764). These results indicate that the RBC assay is a useful and rapid test for use as a screening method to assess the IP of cosmetic products, and for predicting the IP value with a high level of concordance (94.7%). The assay showed high sensitivity and specificity rates of 91.6% and 100%, respectively.