Production of methylmercury by sulphate-reducing bacteria in sediments from the orbetello lagoon in presence of high macroalgal loads

Methylmercury is a potent neurotoxin affecting shallow-water ecosystems. Mercury polluted sediment samples were collected at six different sites in the Orbetello Lagoon (central Italy) characterized by high levels of silt, iron, manganese hydroxides, and organic matter originated the latter originated from the decomposition of macroalgae. Porous water pointed out the presence of sulphates, methylmercury, and sulphides. Slurries arranged in anaerobic conditions from sediment aliquots from the six sites, with the addition of ionic mercury, highlighted the production of methylmercury. Sulphate reducing bacteria (SRB) were quantified in lagoon sediments; furthermore, sediments cultured under anaerobic conditions showed SRBs active in mercury methylation. Anaerobic cultures of SRB, amended with ionic mercury, produced methylmercury during the growth of bacterial cells. The percentage of aerobic mercury resistant bacteria was pointed out at each sampling site, evidencing the presence of bioavailable mercury. Several aerobic mercury resistant bacteria were isolated and their level of resistance to inorganic and organic forms of mercury was evaluated. These isolates may be potentially used for eventual bioremediation processes. Mercury methylation by SRB in the Orbetello Lagoon sediments was described for the first time, focusing the attention on the need for possible bioremediation processes by using autochthonous mercury resistant bacteria. Moreover, the influence of algal biomass on mercury methylation was highlighted for the first time in this lagoon ecosystem. The importance of removing algal biomass, as it represents a source of organic matter favouring the process of mercury methylation, was strongly pointed out in this study

Robotic total gastrectomy with intracorporeal robot-sewn anastomosis. A novel approach adopting the double-loop reconstruction method

Gastric cancer constitutes a major health problem. Robotic surgery has been progressively developed in this field. Although the feasibility of robotic procedures has been demonstrated, there are unresolved aspects being debated, including the reproducibility of intracorporeal in place of extracorporeal anastomosis. Difficulties of traditional laparoscopy have been described and there are well-known advantages of robotic systems, but few articles in literature describe a full robotic execution of the reconstructive phase while others do not give a thorough explanation how this phase was run. A new reconstructive approach, not yet described in literature, was recently adopted at our Center. Robotic total gastrectomy with D2 lymphadenectomy and a socalled ‘‘double-loop’’ reconstruction method with intracorporeal robotsewn anastomosis (Parisi’s technique) was performed in all reported cases. Preoperative, intraoperative, and postoperative data were collected and a technical note was documented. All tumors were located at the upper third of the stomach, and no conversions or intraoperative complications occurred. Histopathological analysis showed R0 resection obtained in all specimens. Hospital stay was regular in all patients and discharge was recommended starting from the 4th postoperative day. No major postoperative complications or reoperations occurred. Reconstruction of the digestive tract after total gastrectomy is one of the main areas of surgical research in the treatment of gastric cancer and in the field of minimally invasive surgery. The double-loop method is a valid simplification of the traditional technique of construction of the Roux-limb that could increase the feasibility and safety in performing a full hand-sewn intracorporeal reconstruction and it appears to fit the characteristics of the robotic system thus obtaining excellent postoperative clinical outcome

BeeNet and BEST: the Italian 'beekeeping and environment' projects

Tese de doutoramento em Engenharia Civil, no ramo de Geotecnia, apresentada ao Departamento de Engenharia Civil da Faculdade de Ciências e Tecnologia da Universidade de CoimbraO estudo e a caracterização de solos incoerentes, nomeadamente areias saturadas, foram impulsionados pela ocorrência de diversos incidentes, entre os quais se destacam os sismos de 1964 no Alasca (Estados Unidos da América) e em Niigata (Japão). Os severos danos registados durante estes sismos alertaram a comunidade científica para os efeitos associados aos fenómenos de liquefação, impulsionando o desenvolvimento da disciplina de engenharia sísmica geotécnica. No final do século XX, o início do estudo sistemático do comportamento de solos no domínio das pequenas deformações vem complementar o conhecimento da resposta não drenada de areias, fornecendo ferramentas adequadas para o dimensionamento tanto aos estados limites de utilização como aos estados limites últimos. Apesar dos avanços científicos no estudo do comportamento de areias saturadas, abalos sísmicos mais recentes, como os sismos de Kobe (1995, Japão) e Kocaeli (1999, Turquia), demonstraram que a previsão de fenómenos de liquefação e seus efeitos não estão totalmente compreendidos. Atendendo à história sísmica de Portugal bem como ao facto de as principais cidades portuguesas se situarem no litoral ou nas margens de rios, o Departamento de Engenharia Civil da Universidade de Coimbra, com a colaboração de outras duas instituições de ensino superior nacionais, encetou, em 2008, um vasto programa de investigação sobre ferramentas para o dimensionamento baseado no desempenho em maciços suscetíveis à liquefação. Para esta investigação, foi escolhida uma areia local recolhida nas margens do Rio Mondego que, após o seu tratamento, origina uma fração uniforme designada de areia de Coimbra, material que se propõe caracterizar, dando seguimento a vários estudos já elaborados. Os dados da extensa investigação laboratorial concretizada resultam de ensaios realizados sobre amostras cilíndricas de secção cheia mas, essencialmente, de ensaios executados num HCA Mark II sobre provetes cilíndricos ocos cujas dimensões são 60Di:100Do:200H (mm). A conclusão da instalação deste equipamento, o desenvolvimento de procedimentos de calibração dos seus instrumentos de medição bem como o estabelecimento de técnicas de preparação de provetes e de execução de ensaios constituem a primeira parte desta dissertação. Estas informações técnicas, que incluem a descrição detalhada de todos os componentes do HCA da Universidade de Coimbra, é complementada com uma exposição dos pressupostos e conceitos teóricos que permitem a definição dos estados de tensão e deformação em amostras cilíndricas ocas. A caracterização avançada do comportamento mecânico da areia de Coimbra, que sucede estudos microscópicos e de identificação que complementam informações anteriormente publicadas, perfaz a segunda parte desta dissertação. Os ensaios laboratoriais incidem sobre amostras de areia reconstituídas e saturadas, incluindo ensaios monotónicos e cíclicos em condições não drenadas para diferentes modos de carregamento e estados iniciais. A versatilidade do HCA, além da caracterização no domínio das pequenas deformações do solo analisado, permite a imposição de condições de restrição de deformação pouco convencionais no estudo de liquefação de areias. Por fim, descreve-se o comportamento pós-liquefação da areia de Coimbra, com especial enfoque nas deformações volumétricas e na variação do estado de tensão.The characterisation of cohesionless soils, namely saturated sands, was encouraged by several seismic events such as the 1964 earthquakes in Alaska (USA) and Niigata (Japan). The severe damages observed during and after these earthquakes drew the attention of the scientific community to liquefaction-related phenomena. It is also accepted that these two earthquakes are at the origin of the geotechnical earthquake engineering. By the end of the 20th century, extensive research programmes on the small strain behaviour of soils improved considerably the knowledge of the stress- strain response of sands, providing the appropriate tools for the design of both serviceability and ultimate limit states. Despite all the scientific advances in the study of the behaviour of saturated sand, recent earthquakes, such as Kobe’s earthquake in 1995 (Japan) and the Kocaeli’s earthquake in 1999 (Turkey), sowed that the prediction of liquefaction-related phenomena and their effects were not fully understood. Given Portugal’s seismic history, as well as the fact that its major cities are located on the coast or in proximity to rivers, the Department of Civil Engineering of the University of Coimbra, Portugal, began in 2008, in collaboration with two other Portuguese Universities, a comprehensive research programme with the objective of developing performance- based design tools for liquefiable deposits. A local sand, named Coimbra sand, obtained from sand collected on the banks of the Mondego River, has been used for this investigation. The present investigation aims at characterising the mechanical response of this sand, highlighting some features of its behaviour that have not been studied yet. The comprehensive experimental research carried out comprises data from tests performed on both conventional cylindrical samples and hollow cylindrical samples with dimensions 60Di:100Do:200H (mm) tested in a Hollow Cylinder Apparatus Mark II. The set up of this apparatus, the development of the calibration procedures for the measurement instruments, as well as the proposal of sample preparation techniques, compose the first part of this thesis. This technical information, which comprises a fully detailed description of all of the University of Coimbra’s HCA components, is accompanied by a discussion of all the assumptions and theoretical principles needed for the definition of the stress and strain states in a hollow cylindrical sample. Microscopic and fundamentals studies, which complete the data published in previous works, precede the advanced characterisation of the mechanical behaviour of Coimbra sand, constituting the second part of this thesis. All the laboratory tests are carried on remoulded and saturated sand samples, and comprise monotonic and cyclic undrained shear tests for both different loading modes and initial states. The versatility of the HCA enables not only the characterization of the small strain stiffness behaviour of Coimbra sand but also the use of unconventional deformation-restricted conditions in the study of sand liquefaction. Lastly, the post-liquefaction behaviour of Coimbra sand is described, with particular emphasis on the development of volumetric strains and evolution of stress state.L’étude et la caractérisation des sols incohérents, notamment des sables saturés, ont été encoutagées par de tragiques évènements sismiques, parmi lesquels se trouvent les tremblements de terre de 1964 en Alaska (Etats-Unis d’Amérique) et à Niigata (Japon). Les importants dégâts enregistrés au cours de ces violents tremblements de terre ont alerté la communauté scientifique et face aux effets de ces phénomènes liés à la liquéfaction des sables, une discipline du domaine du Génie Civil a été créée: Parasismique et Géotechnique. Vers la fin du XXe siècle, le début des études du comportement des sols sous l’hypothèse des petites perturbations vient compléter la connaissance du comportement non drainé des sables et fournir les outils nécessaires pour le dimensionnement aux états limites ultimes et en service. Malgré tous les progrès scientifiques, des tremblements de terre récents, comme ceux que ont eut lieu à Kobe en 1995 (Japon) et à Kocaeli en 1999 (Turquie), ont démontré que la prédiction bien comme les effets des phénomènes liés à la liquéfaction n’étaient pas intégralement assimilés. Étant donné l’histoire sismologique du Portugal aussi bien comme le fait que les villes portugaises les plus importantes sont établies sur la côte ou sur les berges de fleuves, le Département de Génie Civil de l’Université de Coimbra au Portugal, en collaboration avec deux autres établissements de génie civil nationaux, a entamé, en 2008, un ample programme de recherche sur les outils pour le dimensionnement basé sur la performance des sols susceptibles à la liquéfaction. Les recherches sont menées sur le sable de Coimbra, qui est le résultat du traitement d’un sable locale recueilli sur les rives du fleuve Mondego. La présente étude vise caractériser ce sol en apportant des renseignements encore jamais étudiés auparavant. Les résultats de cette ample recherche réalisée en laboratoire proviennent d’essais triaxiaux sur des échantillons conventionnels de sable et sur des échantillons cylindriques creux. Ces derniers ont été effectués avec une cellule triaxiale à cylindre creux du type HCA Mark II, qui permet, entre autres, d’essayer des éprouvettes cylindriques creuses dont les dimensions sont de 60Di:100De:200H (mm). L’achèvement de l’installation de cet équipement, le développement de procédures d’étalonnage de ses instruments de mesure bien comme de techniques de préparation d’éprouvettes creuses composent la première partie de cette thèse. Cet exposé inclut une description très détaillée du HCA de l’Université de Coimbra ainsi que l’exposition des hypothèses et des notions théoriques qui permettent de définir les états de contrainte et de déformation dans des essaies de cylindres creux. La deuxième partie de cette thèse rassemble les résultats de la caractérisation du comportement mécanique du sable de Coimbra, qui succède à des études microscopiques et d’identification. Les études en laboratoire comprennent uniquement des échantillons de sable remaniés et saturés, lesquels sont soumis à des essais de cisaillement non drainés sous différents modes de chargements monotones et cycliques pour différentes conditions initiales. La polyvalence de la cellule triaxiale à cylindre creux permet aussi d’imposer des restrictions de déformations non conventionnelles dans l’étude de la liquéfaction des sables e ains que leur caractérisation sous l’hypothèse des petites perturbations. En dernier lieu, ce travail présente des données sur le comportement post liquéfaction du sable de Coimbra, en mettant l’accent sur les déformations volumétriques et la variation de l’état de contrainte

A case of a paraduodenal hernia with a concomitant mesosigmoid defect

Abstrac

Can the measurement of amylase in drain after distal pancreatectomy predict post-operative pancreatic fistula?

The most frequent reason for performing a distal pancreatectomy is the presence of cystic or neuroendocrine tumors, in which the distal pancreatic stump is often soft and non fibrotic. This parenchymal consistence represents the main risk factor for post-operative pancreatic fistula. In order to identify the fistula and assessing its severity postoperative monitoring of amylase from intraperitoneal drains is important

Penggunaan Media Model dalam Pembelajaran IPA

This study aims to describe the increase in interest and student learning outcomes in science teaching in primary schools. Classroom action research was conducted in two cycles, each cycle consisted of two meetings with the various forms of energy and material use. Research subjects elementary school students grade IV No 20 Gunung Pangilun Padang Utara. The instrument of this study is the observation sheet student\u27s interests, learning activities observation sheets, and achievement test students\u27 interest in learning the instrument. The results showed that students\u27 interest in learning science in one cycle is 64.4 percent, and in the second cycle of 82.2 percent. Student learning outcomes in a single cycle on average 63.5 and 83.5 in the two cycle becomes. Besides that, it also revealed that an increasing mastery learning students from one cycle is 45.8 percent and in the second cycle of 91.6 percent. Analysis of teachers in implementing learning activities in a cycle that is 79.1 per cent and 91.6 per cent of the second cycle. The use of models in the media can increase interest in science learning, learning outcomes and teacher activities . Therefore, the model can be used medium primary school teachers as one of the media in learning science . Besides, teachers also need to make a good plan in accordance with the science curriculum in elementary schools

Automated QoE Evaluation of Dynamic Adaptive Streaming over HTTP

Dynamic Adaptive Streaming over HTTP (DASH) is referred to as a multimedia streaming standard to deliver high quality multimedia content over the Internet using conventional HTTP Web servers. As a fundamental feature, it enables automatic switching of quality levels according to network conditions, user requirements, and expectations. Currently, the proposed adaptation schemes for HTTP streaming mostly rely on throughput measurements and/or buffer-related metrics, such as buffer exhaustion and levels. In this paper, we propose to enhance the DASH adaptation logic by feeding it with additional information from our evaluation of the users' perception approximating the userperceived quality of video playback. The proposed model aims at conveniently combining TCP-, buffer-, and media content-related metrics as well as user requirements and expectations to be used as an input for the DASH adaptation logic. Experiments have demonstrated that the chosen model enhances the capability of the adaptation logic to select the optimal video quality level. Finally, we integrated all our findings into a real DASH system with QoE monitoring capabilitie