Estudo Comparativo de Métricas de Pontuação para Aprendizagem Estrutural de Redes Bayesianas

Bayesian networks are powerful tools as they represent probability distributions as graphs. They work with uncertainties of real systems. Since last decade there is a special interest in learning network structures from data. However learning the best network structure is a NP-Hard problem, so many heuristics algorithms to generate network structures from data were created. Many of these algorithms use score metrics to generate the network model. This thesis compare three of most used score metrics. The K-2 algorithm and two pattern benchmarks, ASIA and ALARM, were used to carry out the comparison. Results show that score metrics with hyperparameters that strength the tendency to select simpler network structures are better than score metrics with weaker tendency to select simpler network structures for both metrics (Heckerman-Geiger and modified MDL). Heckerman-Geiger Bayesian score metric works better than MDL with large datasets and MDL works better than Heckerman-Geiger with small datasets. The modified MDL gives similar results to Heckerman-Geiger for large datasets and close results to MDL for small datasets with stronger tendency to select simpler network structures

Pulsed Nd:YAG laser welding of Ni-alloy Hastelloy C-276 foils

In this study a pulsed Nd:YAG laser was used to join Hastelloy C-276 thin foil with 100 microns thickness. Pulse energy was varied from 1.0 to 2.25 J at small increments of 0.25 J with a 4 ms pulse duration. The macro and microstructures of the welds were analyzed by optical and electronic microscopy, tensile shear test and microhardness. Sound laser welds without discontinuities were obtained with 1.5 J pulse energy. Results indicate that using a precise control of the pulse energy, and so a control of the dilution rate, it is possible to weld Hastelloy C-276 thin foil by pulsed Nd: YAG laser. (C) 2012 Published by Elsevier B. V. Selection and/or review under responsibility of Bayerisches Laserzentrum GmbH

The X-ray crystallographic structure of the angiogenesis inhibitor angiostatin

Angiogenesis inhibitors have gained much public attention recently as anti-cancer agents and several are currently in clinical trials, including angiostatin (Phase I, Thomas Jefferson University Hospital, Philadelphia, PA). We report here the bowl-shaped structure of angiostatin kringles 1-3, the first multi-kringle structure to be determined. All three kringle lysine-binding sites contain a bound bicine molecule of crystallization while the former of kringle 2 and kringle 3 are cofacial. Moreover, the separation of the kringle 2 and kringle 3 lysiner binding sites is sufficient to accommodate the a-helix of the 30 residue pepticle VEK-30 found in the kringle 2/VEK-30 complex. Together the three kringles produce a central cavity suggestive of a unique domain where they may function in concert. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Intermolecular interactions and characterization of the novel factor Xa exosite involved in macromolecular recognition and inhibition: Crystal structure of human Gla-domainless factor Xa complexed with the anticoagulant protein NAPc2 from the hematophagous nematode Ancylostoma caninum

NAPc2, an anticoagulant protein from the hematophagous nematode Ancylostoma caninum evaluated in phase-II/IIa clinical trials, inhibits the extrinsic blood coagulation pathway by a two step mechanism, initially interacting with the hitherto uncharacterized factor Xa exosite involved in macromolecular recognition and subsequently inhibiting factor VIIa (K-i = 8.4 pM) of the factor VIIa/tissue factor complex. NAPc2 is highly flexible, becoming partially ordered and undergoing significant structural changes in the C terminus upon binding to the factor Xa exosite. In the crystal structure of the ternary factor Xa/NAPc2/selectide complex, the binding interface consists of an intermolecular antiparallel beta-sheet formed by the segment of the polypeptide chain consisting of residues 74-80 of NAPc2 with the residues 86-93 of factor Xa that is additional maintained by contacts between the short helical segment (residues 67-73) and a turn (residues 26-29) of NAPc2 with the short C-terminal helix of factor Xa (residues 233-243). This exosite is physiologically highly relevant for the recognition and inhibition of factor X/Xa by macromolecular substrates and provides a structural motif for the development of a new class of inhibitors for the treatment of deep vein thrombosis and angioplasty. (c) 2006 Elsevier Ltd. All rights reserved.

The X-ray crystallographic structure of Escherichia coli branching enzyme

Branching enzyme catalyzes the formation of alpha-1,6 branch points in either glycogen or starch. We report the 2.3-Angstrom crystal structure of glycogen branching enzyme from Escherichia coli. The enzyme consists of three major domains, an NH2-terminal seven-stranded beta-sandwich domain, a COOH-terminal domain, and a central alpha/beta-barrel domain containing the enzyme active site. While the central domain is similar to that of all the other amylase family enzymes, branching enzyme shares the structure of all three domains only with isoamylase. Oligosaccharide binding was modeled or branching enzyme using the enzyme-oligosaccharide complex structures of various alpha-amylases and cyclodextrin glucanotransferase and residues were implicated in oligosaccharide binding. While most of the oligosaccharides modeled well in the branching enzyme structure, an approximate 50degrees rotation between two of the glucose units was required to avoid steric clashes with Trp(298) of branching enzyme. A similar rotation was observed in the mammalian alpha-amylase structure caused by an equivalent tryptophan residue in this structure. It appears that there are two binding modes for oligosaccharides in these structures depending on the identity and location of this aromatic residue.

Study of the effects of exposure to ionizing irradiation on the materials used for dental restoration

A quantitative study was made about the effects caused by ionizing irradiation on materials used for dental restoration (amalgams, compound resins and compomere), aiming to alleviate in bearers of head and neck cancer, the possible harmful effects of radiotherapy perceived when the repaired teething is within the radiation field. Research also encourages further studies for new alternative materials to be used in dental repair of patients submitted to radiotherapy for head and neck cancer. Test samples were submitted to a gamma radiation beam coming from a cobalt-therapy source and analyzed according to the X-ray fluorescence technique, comparing the chemical composition of the samples before and after irradiation. Radiation detectors such as an ionization chamber and a Geiger-Muller were used to measure the rate of residual dose. Gamma spectrometry with Nal detectors was also performed on the same samples. Results showed that there was no significant change in the chemical composition and that at post-irradiation, samples did not exhibit radiation emission, that is to say they had not become radioactive.

Identificação de padrões da dengue em municípios paulistas entre os anos de 2003 a 2011

Pós-graduação em Biociências - FCLAS

Photoelectron multipliers based on avalanche pn - i - pn structures

We present a new physical principle to design an optoelectronic device, which consists of a multilayered semiconductor structure, where the necessary conditions for generation of photoelectrons are met, such that it will enable sequential avalanche multiplication of electrons and holes inside two depletion slabs created around the p - n junctions of a reverse biased pn - i - pn structure. The mathematical model and computer simulations of this Semiconductor Photo-electron Multiplier (SPEM) for different semiconductor materials are presented. Its performance is evaluated and compared with that of conventional devices. The Geiger operational mode is briefly discussed which may be used in Silicon Photomultiplier (SiPM) as an elementary photo detector to enhance its performance.

Distribuição e dispersão dos níveis radiométricos do setor técnico de medicina nuclear do hospital das clínicas da faculdade de medicina de botucatu

Nuclear medicine uses non-sealed sources for exams and treatments, because the movement of these sources, source of patients injected or not, involve a wide range of environmental radiometric levels. To better control of these levels this study was aimed at monitoring points strategically distributed in all environments Sector Technical Nuclear Medicine, Hospital of the Botucatu Medical School, performing two measurements at random times daily for a period of three months, sampling the normal routine of the sector. The detector Geiger-Muller was used for the acquisition of exposure rates of the points, efficiency and reprodutibility test have shown good performance of this equipment for this purpose. The results allowed to make a projection of annual dose for each environment indicating higher risks for Occupationally Exposed Individuals as well as Public Individuals compared with the limits established by the National Commission of Nuclear Energy. Was developed a spatial map of dose that can be used as a visual warning to the regions with the highest exposure to ionizing radiation, enabling reduced risk of a potential exposure

Aplicações práticas de proteção radiológica nas áreas de medicina nuclear e radiodiagnóstico em instalações hospitalares

After the discovery of ionizing radiation, its applications in various fields of science began to take significant proportions. In the case of medicine, there are the application areas in radiotherapy, diagnostic radiology and nuclear medicine. It was then necessary to create the field of radiological protection to establish the conditions necessary for the safe use of such ionizing radiation. Apply knowledge obtained during the graduation stage and in the practice of radiological protection in the areas of nuclear medicine and diagnostic radiology. In the area of nuclear medicine, tests were made in the Geiger-Muller counters (GM) and the dose calibrator (curiometer), the monitoring tests of radiation, waste management, clean of the Therapeutic room and testing the quality control of gamma-chambers. In the area of radiology, were performed tests of quality control equipment for conventional X-ray equipment and x-ray fluoroscopy, all following the rules of the National Health Surveillance Agency (ANVISA), and reporting of tests. The routine developed in the fields of nuclear medicine in hospitals has proved very useful, since the quality control of GM counters contribute to the values of possible contamination are more reliable. The control of dose calibrator enables the patient not to receive different doses of the recommended amounts, which prevents the repetition of tests and unnecessary exposure to radiation. The management of waste following the rules and laws established and required for its management. Tests for quality control of gamma chambers help to evaluate its medical performance through image. In part of diagnostic radiology, tests for quality control are performed in order to verify that the equipment is acceptable for usage or if repairs are needed. The knowledge acquired at the internship consolidated the learning of graduation course

Mapeamento do nível radiométrico e construção de mapa espacial em serviço de medicina nuclear

Nuclear Medicine is a medical modality of therapy and diagnostic imaging using unsealed radioactive sources for its purposes. This routine activity promotes the transit of radioactive sources for the area of installation, beyond the transit of patients injected with radioisotope, which also contribute to raising the radiometric level of environment. As a consequence, it has exposured workers and public individuals to the ionizing radiation. There are protective mechanisms of radiation exposure, personal protective equipments, and measurement planes established in standard measurement at certain points of the environment in order to identify any increase in radiometric levels and \ or contamination, but do not cover the entire space occupied by workers and patients. To accomplish with the individual dose limits established by the National Commission of Nuclear Energy, it is interesting if there is an individualized classification for each Nuclear Medicine service. This work aimed to promote an analysis of the radiometric level distribution across the extent of the Technical Nuclear Medicine Sector of Hospital of the Botucatu Medical School, and produce a spatial map to identify locations with higher exposure rate to the ionizing radiation, can be used as a risk map to assist the Occupationally Exposed Individuals (IOE). To perform the radiometric levels checking it was used a digital Geiger-Muller detector available in the sector, due to its practicality compared to other detectors. Measurements were carried out at four different times for all days of the week, at points strategically established to cover all the installation

Metabolism

Review

A model of ischemic isolated acute liver failure in pigs: standardizing monitoring and treatment

Acute liver failure (ALF) models in pigs have been widely used for evaluating newly developed liver support systems. But hardly any guidelines are available for the surgical methods and the clinical management.