Itaipu Binacional: sfruttamento eco e socio sostenibile di una risorsa comune nel processo di integrazione latinoamericana.

Itaipu Binacional è una centrale idroelettrica costruita tra Brasile e Paraguay come risultato di una controversia diplomatica riguardante la sovranità nazionale su alcuni territori contesi. Tale controversia si risolse con la costruzione congiunta di una centrale che avrebbe prodotto, da quel momento in poi, energia per i due paesi creando occupazione e sviluppo economico e sfruttando la risorsa naturale più abbondante della zona: le acque del fiume Paranà. Dallo sfruttamento meramente energetico del Paranà, Itaipu passa ad occuparsi dei danni ambientali procurati all'ambiente, delle popolazioni che ne hanno risentito e di tutti coloro che, dalle risorse della zona traggono sostentamento. Col cambio di missione e con il rinnovo della direzione esecutiva, verificatisi nel 2003, gli impegni legati alla responsabilità ambientale e sociale dell'impresa diventano linee guida fondamentali di Itaipu che avvia centinaia di progetti finalizzati al raggiungimento dello sviluppo eco e socio sostenibile della popolazione paraguayana e brasiliana e delle risorse naturali nazionali

Corrosion and wear resistance analysis of ASTM F 138 austenitic stainless steel treated by laser

Orientador: Maria Clara Filippini IerardiTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia MecânicaResumo: No presente trabalho, o aço inoxidável austenítico ASTM F 138, empregado na fabricação de implantes ortopédicos temporários e permanentes, foi submetido a tratamento de superfície por laser, com o intuito de analisar as modificações microestruturais resultantes deste tratamento e seus efeitos na resistência à corrosão e ao desgaste microabrasivo. A caracterização microestrutural foi feita por microscopia óptica, microscopia eletrônica de varredura, microdureza Vickers e difração de raios-X. Para analisar o comportamento em corrosão do aço, antes e após o tratamento, foram realizados três tipos diferentes de ensaios eletroquímicos usando solução de Ringer como eletrólito. O comportamento em desgaste foi avaliado a partir de ensaios por microabrasão do tipo esfera-sobre-placa, utilizando como abrasivos uma suspensão de partículas de carboneto de silício (SiC) em água destilada e uma suspensão de SiC em solução de Ringer. Após o tratamento por laser, o aço apresentou uma microestrutura refinada constituída por dendritas de austenita, com um aumento de aproximadamente 23% na dureza e com melhoria frente à corrosão e ao desgaste.Abstract: In this work, ASTM F 138 austenitic stainless steel, used in temporary and permanent orthopaedic implants manufacture, was subjected to laser surface treatment. The purpose is analyze the microstructural changes resulting from this treatment and their effects on the microabrasive wear and corrosion resistance. The microstructural characterization was performed by optical microscopy, scanning electron microscopy, Vickers microhardness and X-ray diffraction. In order to analyze the corrosion behavior, three different types of electrochemical tests were carried out before and after treatment, using Ringer's solution as electrolyte. The wear behavior was evaluated using ball-cratering microabrasive wear tests, using slurry of silicon carbide particles (SiC) in distilled water and slurry of SiC in Ringer's solution. After laser treatment, the steel presented a refined microstructure consisted of austenite dendrites, with a 23% hardness increase and improved corrosion and wear resistance.DoutoradoMateriais e Processos de FabricaçãoDoutor em Engenharia Mecânic

The magnetic environment in the central region of nearby galaxies

The central regions of galaxies harbor some of the most extreme physical phenomena, including dense stellar clusters, non-circular motions of molecular clouds and strong and pervasive magnetic field structures. In particular, radio observations have shown that the central few hundred parsecs of our Galaxy has a striking magnetic field configuration. It is not yet clear whether these magnetic structures are unique to our Milky Way or a common feature of all similar galaxies. Therefore, we report on (a) a new radio polarimetric survey of the central 200 pc of the Galaxy to better characterize the magnetic field structure and (b) a search for large-scale and organized magnetized structure in the nuclear regions of nearby galaxies using data from the Very Large Array (VLA) archive. The high angular resolution of the VLA allows us to study the central 1 kpc of the nearest galaxies to search for magnetized nuclear features similar to what is detected in our own Galactic center. Such magnetic features play a important role in the nuclear regions of galaxies in terms of gas transport and the physical conditions of the interstellar medium in this unusual region of galaxies.Comment: 8 pages; Proceedings for "The Universe under the Microscope" (AHAR 2008), held in Bad Honnef (Germany) in April 2008, to be published in Journal of Physics: Conference Series by Institute of Physics Publishing, R. Schoedel, A. Eckart, S. Pfalzner, and E. Ros (eds.

Length of the healthy and pathological small intestine in patients with Crohn’s disease: calculations using computed tomography and magnetic resonance enterography

Many patients with Crohn’s disease (CD) require surgical intervention during their lifetime. A correct preoperative assessment of the intestinal length is necessary to predict and quickly treat postoperative nutritional disorders. The aim of this paper is to explain the method used in our hospital to measure intestinal length in patients with CD and its usefulness for making the correct therapeutic decision. Vessel analysis software is used to measure small bowel length through computed tomography enterography (CTE) or magnetic resonance enterography (MRE). The method permits two-dimensional and three-dimensional curved multiplanar reconstructions and allows each loop to be stretched using a point-by-point identification of the intestinal lumen. Subsequently, the software allows the creation of a virtual image, on which the intestinal length is measured linearly. This methodology was tested on three patients; patients 1 and 3 were examined using CTE, and patient 2 was examined using MRE. The outcomes were discussed at a multidisciplinary team meeting (MDT). As a result, surgical ileocolic resection was recommended for patient 1 and medical therapy for patients 2 and 3. Intestinal length measurements have proved vital during MDTs for making appropriate therapeutic decisions

CT of the acute colonic diverticulitis: a pictorial essay

Acute colonic diverticulitis (ACD) is an acute episode of severe and prolonged lower abdominal pain due to diverticular inflammation, usually associated with change in bowel movements, fever, and leukocytosis. Worldwide, computed tomography (CT) of the abdomen and pelvis with intravenous contrast is accepted as the best imaging method for evaluating the diverticular inflammation, serving the following functions: confirming the presence of ACD; evaluation of the disease severity and degree; therapy planning guide in presence of complications (such as abscess or intestinal perforation); diagnosis of other diseases that may simulate diverticular inflammation. In the literature, we found values of CT sensitivity for diverticular inflammation from 79% to 99%; CT is useful in differentiating other diseases, which may cause abdominal pain, when diverticular inflammation is not the cause, such as neoplasm, inflammatory bowel disease, appendix inflammations, epiploic appendix inflammation and colon ischemia. The trick to differentiate diverticulitis from other inflammatory diseases that involve the colon is the identification of diverticula in the pathological intestinal loop. In the last years, a radiological classification was created in order to guide the management of ACD in patients treated conservatively or with interventional procedures. The new classification system divides ACD into two groups: complicated and uncomplicated. Uncomplicated ACD is defined if only thickening of the intestinal wall is present, with increase of the perivisceral fat density. Complicated ACD is divided into 4 stages, depending on presence of microperforation without abscess and/or peritoneum involvement (stage 1 A), presence of abscess with diameter ≤4 cm (stage 1 B), presence of abscess with diameter >4 cm (stage 2 A), presence of distant air >5 cm from the pathological loop (stage 2 B), presence of diffuse fluid in at least two distant abdominal quadrants without distant free air (stage 3), presence of diffuse fluid and distant free air (stage 4). In this pictorial essay, we describe CT findings of the ACD and explain classification of the disease and its common and uncommon complications

assessment of crohn s disease activity magnetic resonance enterography in comparison with clinical and endoscopic evaluations

Crohn's disease (CD) is a chronic inflammatory transmural disease of the gastrointestinal tract. The small bowel is the most frequently involved site. Assessment of the bowel is essential in guiding therapeutic decisions, medical or surgical therapy. Personalized medicine is a new concept that has the potential to improve therapeutic efficacy, reduce the risk of drug adverse events, and decrease costs if the therapy is the most suitable treatment for selected patients. Many techniques have been verified and standardised for small bowel CD. Among radiological techniques, CT enterography (CTE) and MRI-enterography (MRE) are the most widely accepted techniques, although MRI is generally preferable as it avoids radiation. In this review, we will present the current role and new innovative technological perspectives of MR enterography in comparison with clinical and endoscopic evaluations for the assessment of CD activity in adult patients. In particular, many studies have been performed to validate MRE signs such as biomarkers of active Crohn's disease (such as mural thickening, mural T2 hyperintense signal, target sign, comb sign, ulceration and extramural mesenteric signs) and to select the most appropriate index for identifying active disease or severe inflammation (such as MaRIA score, Clermont index, and others). We conclude that MRE is a minimally invasive tool for the evaluation of disease activity and shows a very good correlation with the presence and severity of endoscopic lesions, so to allow a personalized medicine in patients with CD

Efficacy and safety of LDL-lowering therapy among men and women: meta-analysis of individual data from 174,000 participants in 27 randomised trials

Background Whether statin therapy is as effective in women as in men is debated, especially for primary prevention. We undertook a meta-analysis of statin trials in the Cholesterol Treatment Trialists' (CTT) Collaboration database to compare the effects of statin therapy between women and men. Methods We performed meta-analyses on data from 22 trials of statin therapy versus control (n=134 537) and five trials of more-intensive versus less-intensive statin therapy (n=39 612). Effects on major vascular events, major coronary events, stroke, coronary revascularisation and mortality were weighted per 1·0 mmol/L reduction in LDL cholesterol and effects in men and women compared with a Cox model that adjusted for non-sex differences. For subgroup analyses, we used 99% CIs to make allowance for the multiplicity of comparisons. Findings 46 675 (27%) of 174 149 randomly assigned participants were women. Allocation to a statin had similar absolute effects on 1 year lipid concentrations in both men and women (LDL cholesterol reduced by about 1·1 mmol/L in statin vs control trials and roughly 0·5 mmol/L for more-intensive vs less-intensive therapy). Women were generally at lower cardiovascular risk than were men in these trials. The proportional reductions per 1·0 mmol/L reduction in LDL cholesterol in major vascular events were similar overall for women (rate ratio [RR] 0·84, 99% CI 0·78–0·91) and men (RR 0·78, 99% CI 0·75–0·81, adjusted p value for heterogeneity by sex=0·33) and also for those women and men at less than 10% predicted 5 year absolute cardiovascular risk (adjusted heterogeneity p=0·11). Likewise, the proportional reductions in major coronary events, coronary revascularisation, and stroke did not differ significantly by sex. No adverse effect on rates of cancer incidence or non-cardiovascular mortality was noted for either sex. These net benefits translated into all-cause mortality reductions with statin therapy for both women (RR 0·91, 99% CI 0·84–0·99) and men (RR 0·90, 99% CI 0·86–0·95; adjusted heterogeneity p=0·43). Interpretation In men and women at an equivalent risk of cardiovascular disease, statin therapy is of similar effectiveness for the prevention of major vascular events.UK Medical Research Council, British Heart Foundation, Australian National Health and Medical Research Council, European Community Biomed Program

Human G Protein–Coupled Receptor Gpr-9-6/Cc Chemokine Receptor 9 Is Selectively Expressed on Intestinal Homing T Lymphocytes, Mucosal Lymphocytes, and Thymocytes and Is Required for Thymus-Expressed Chemokine–Mediated Chemotaxis

TECK (thymus-expressed chemokine), a recently described CC chemokine expressed in thymus and small intestine, was found to mediate chemotaxis of human G protein–coupled receptor GPR-9-6/L1.2 transfectants. This activity was blocked by anti–GPR-9-6 monoclonal antibody (mAb) 3C3. GPR-9-6 is expressed on a subset of memory α4β7high intestinal trafficking CD4 and CD8 lymphocytes. In addition, all intestinal lamina propria and intraepithelial lymphocytes express GPR-9-6. In contrast, GPR-9-6 is not displayed on cutaneous lymphocyte antigen–positive (CLA+) memory CD4 and CD8 lymphocytes, which traffic to skin inflammatory sites, or on other systemic α4β7−CLA− memory CD4/CD8 lymphocytes. The majority of thymocytes also express GPR-9-6, but natural killer cells, monocytes, eosinophils, basophils, and neutrophils are GPR-9-6 negative. Transcripts of GPR-9-6 and TECK are present in both small intestine and thymus. Importantly, the expression profile of GPR-9-6 correlates with migration to TECK of blood T lymphocytes and thymocytes. As migration of these cells is blocked by anti–GPR-9-6 mAb 3C3, we conclude that GPR-9-6 is the principal chemokine receptor for TECK. In agreement with the nomenclature rules for chemokine receptors, we propose the designation CCR-9 for GPR-9-6. The selective expression of TECK and GPR-9-6 in thymus and small intestine implies a dual role for GPR-9-6/CCR-9, both in T cell development and the mucosal immune response

Physiogenomic analysis of weight loss induced by dietary carbohydrate restriction

BACKGROUND: Diets that restrict carbohydrate (CHO) have proven to be a successful dietary treatment of obesity for many people, but the degree of weight loss varies across individuals. The extent to which genetic factors associate with the magnitude of weight loss induced by CHO restriction is unknown. We examined associations among polymorphisms in candidate genes and weight loss in order to understand the physiological factors influencing body weight responses to CHO restriction. METHODS: We screened for genetic associations with weight loss in 86 healthy adults who were instructed to restrict CHO to a level that induced a small level of ketosis (CHO ~10% of total energy). A total of 27 single nucleotide polymorphisms (SNPs) were selected from 15 candidate genes involved in fat digestion/metabolism, intracellular glucose metabolism, lipoprotein remodeling, and appetite regulation. Multiple linear regression was used to rank the SNPs according to probability of association, and the most significant associations were analyzed in greater detail. RESULTS: Mean weight loss was 6.4 kg. SNPs in the gastric lipase (LIPF), hepatic glycogen synthase (GYS2), cholesteryl ester transfer protein (CETP) and galanin (GAL) genes were significantly associated with weight loss. CONCLUSION: A strong association between weight loss induced by dietary CHO restriction and variability in genes regulating fat digestion, hepatic glucose metabolism, intravascular lipoprotein remodeling, and appetite were detected. These discoveries could provide clues to important physiologic adaptations underlying the body mass response to CHO restriction