Short crack tolerance under EAC conditions

Notch sensitivity effects under environmentally-assisted cracking (EAC) conditions have been recently quantified considering the tolerance to short cracks that may start at their tips and become non-propagating after growing for a while, a behavior that depends on the stress gradients ahead of the notch tips and on the basic material resistances to crack initiation (SEAC) and propagation (KIEAC) inside an aggressive medium under static loadings. Such properties are time-independent, so they can be directly compared with the notch gradient-affected stress intensity factors of the short cracks that depart from notch tips. This model can provide a powerful alternative design tool for the pass/non-pass criterion traditionally used to deal with such mechanical-chemical problems, since it properly considers and quantifies the stress analysis issues that affect them. This model has been validated by proper tests under liquid metal embrittlement conditions, and it can be used to propose a defect-tolerant design criterion under EAC conditions that includes the unavoidable notch effects always present in actual structural components. This paper objective is to experimentally verify the proposed model predictions under other EAC mechanisms. Among them, hydrogen embrittlement (HE) is a most important one, since many catastrophic failures have been associated to it. Due to its practical importance, two different sources of hydrogen are used in this work to understand the HE short crack behavior: (1) sulfide stress corrosion (SSC) on super martensitic stainless steel in salt water with high amounts of H2S, which produces hydrogen by a corrosive process; and (2) cathodic protection (CP) on a high strength steel in salt water, which produces hydrogen by electrolysis. In both cases, the hydrogen diffusion is slow, due to the martensitic microstructures, although high amounts of hardly-measurable hydrogen may be present around the cracking region. Since the driving force for short cracks can be associated to the stress gradient ahead of the crack tip, the SSC and CP short cracks behavior can be predicted by the same set of procedures previously qualified under liquid metal embrittlement conditions, and with under some SSC tests made with carbon steels. Moreover, a third EAC mechanism is studied in this work as well, chloride-induced cracking in austenitic stainless steels, using a boiling solution of MgCl2

Chemical characterization of passion fruit (Passiflora edulis f. flavicarpa) seeds

The aim of this study was to determine the chemical characteristics of passion fruit seeds and their oil for possible use in human food and reduction of organic waste from fruit industrialization. Passion fruit seeds were analyzed for moisture, lipids, proteins, ash, fibers, titratable acidity, pH, soluble solids and antioxidant activity. The oil was characterized for parameters such as acid value, saponification, iodine and peroxide. The content of oil extracted demonstrates that it has good potential for  industrial utilization. According to analyses, the oil has characteristics similar to conventional edible oils such as soybean, and may be a new source of human consumption. Passion fruit seeds have high nutritional value, proving to be a promising product, mainly because it contains  significant amounts of proteinase. Therefore, passion fruit seeds and their oil should be used as raw material in the food, chemical and pharmaceutical industry, as they have beneficial features.Key words: Industrial utilization, characterization, by-products

Gauss-Bonnet Black Holes and Heavy Fermion Metals

We consider charged black holes in Einstein-Gauss-Bonnet Gravity with Lifshitz boundary conditions. We find that this class of models can reproduce the anomalous specific heat of condensed matter systems exhibiting non-Fermi-liquid behaviour at low temperatures. We find that the temperature dependence of the Sommerfeld ratio is sensitive to the choice of Gauss-Bonnet coupling parameter for a given value of the Lifshitz scaling parameter. We propose that this class of models is dual to a class of models of non-Fermi-liquid systems proposed by Castro-Neto et.al.Comment: 17 pages, 6 figures, pdfLatex; small corrections to figure 10 in this versio

COPPER FRACTIONATION IN PROTEINS FROM PLASMA, MUSCLE AND LIVER OF NILE TILAPIA

COPPER FRACTIONATION IN PROTEINS FROM PLASMA, MUSCLE AND LIVER OF NILE TILAPIA. Copper fractionation in plasma, muscle and liver of Nile tilapia was performed after protein separation by 2D-PAGE. SR XRF analysis indicated the presence of copper in three protein spots of plasma, and in two protein spots of muscle and liver, respectively. Copper ions were found to be distributed mostly in proteins that had a molar mass of less than 54 kDa and greater than 13 kat and a pI in the 5.3-9.3 range. The copper concentration bound to these proteins was determined by GFAAS which showed concentrations in the 1.20-4.82 mg g(-1) range.35349349

Attachment of 2,2-bipyridine onto a silica gel for application as a sequestering agent for copper, cadmium and lead ions from an aqueous medium

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)A method was developed to attach 2,2-bipyridine (BP) onto a silica gel surface by a two-step reaction. The first step consisted of a reaction between the matrix and a silylating agent, 3-chloropropyltrimeth-oxysilane. In the second step of the reaction, a ligand molecule was attached onto Si-CPTS, yielding the product Si-BP. The modified material contained 0.431 +/- 0.01 mmol of 2,2-bipyridine per gram of modified silica, as confirmed by FT-IR spectra of the proposed structure. The surface modification was characterized by the BET technique, which revealed a decrease in the surface area from 614 to 450 m(2) g(-1). The series of adsorption isotherms for the metal ions were adjusted to fit a modified Langmuir equation. The maximum number of moles of copper, cadmium and lead ions adsorbed was 0.64, 0.53, and 0.54 mmol g-1, respectively. The surface saturation was calculated as phi fraction and the values obtained, Cu(II) = 1.160, Cd(II) = 1.044 and Pb(II) = 0.997, suggest a type 1:1 metal-ligand complex.1342833Fundação para o Desenvolvimento da UNESP (FUNDUNESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FUNDUNESP [Proc. 00182/06-DFP]FAPESP [Proc. 06/54946-9

Aortic valve replacement with different types of prosthesis. Are there differences in the outcomes during hospital phase?

Objective: To analyze intraoperative data and possible differences in clinical evolution during postoperative hospital phase for aortic valve replacement surgery using different types of prosthesis. Methods: Analysis of 60 patients divided into three groups. Valve replacement with bioprosthesis (20), mechanical prosthesis (20) and homologous valve (20). The mean age was 51.1, 60% were male and 40% female patients; 86.7% were in NYHA II or III; 63.3% presented arterial hypertension and 18.3% had diabetes. Aetiology of valve disease was degenerative for 39%, rheumatic for 36% and endocardits for 15%. Results: The hospital mortality was 5%; there were no differences in the incidence of septical or cardiogenic intensive care, neither for total time in intensive care and mechanical ventilation. However, there was statistical differences as regards the cardiopulmonary bypass total time (P=0.02) and the aortic clamping time (P<0.0001) unfavorable to homograft valve group. The ward admission time was greater for mechanical valve group (P=0.05) as well as for total admission time, but without statistical significance. It was observed that patients with preoperative hematocrit smaller than 38.1% used 2.73 units of blood components, and with postoperative hematocrit smaller than 32% used 1,79 units of blood components. Echocardiography control showed minimal evolutional differences. Conclusion: The use of different types of prosthesis for this study does not cause differences in the results of postoperative hospital phase. The use of homograft valve is a feasible option with good clinical applicability23453454

How acceptable are antiretrovirals for the prevention of sexually transmitted HIV? A review of research on the acceptability of oral pre-exposure prophylaxis and treatment as prevention

Recent research has demonstrated how antiretrovirals (ARVs) could be effective in the prevention of sexually transmitted HIV. We review research on the acceptability of oral pre-exposure prophylaxis (PrEP) and treatment as prevention (TasP) for HIV prevention amongst potential users. We consider with whom, where and in what context this research has been conducted, how acceptability has been approached, and what research gaps remain. Findings from 33 studies show a lack of TasP research, PrEP studies which have focused largely on men who have sex with men (MSM) in a US context, and varied measures of acceptability. In order to identify when, where and for whom PrEP and TasP would be most appropriate and effective, research is needed in five areas: acceptability of TasP to people living with HIV; motivation for PrEP use and adherence; current perceptions and management of risk; the impact of broader social and structural factors; and consistent definition and operationalisation of acceptability which moves beyond adherence

Updating known distribution models for forecasting climate change impact on endangered species

To plan endangered species conservation and to design adequate management programmes, it is necessary to predict their distributional response to climate change, especially under the current situation of rapid change. However, these predictions are customarily done by relating de novo the distribution of the species with climatic conditions with no regard of previously available knowledge about the factors affecting the species distribution. We propose to take advantage of known species distribution models, but proceeding to update them with the variables yielded by climatic models before projecting them to the future. To exemplify our proposal, the availability of suitable habitat across Spain for the endangered Bonelli’s Eagle (Aquila fasciata) was modelled by updating a pre-existing model based on current climate and topography to a combination of different general circulation models and Special Report on Emissions Scenarios. Our results suggested that the main threat for this endangered species would not be climate change, since all forecasting models show that its distribution will be maintained and increased in mainland Spain for all the XXI century. We remark on the importance of linking conservation biology with distribution modelling by updating existing models, frequently available for endangered species, considering all the known factors conditioning the species’ distribution, instead of building new models that are based on climate change variables only.Ministerio de Ciencia e Innovación and FEDER (project CGL2009-11316/BOS