On dynamic analysis of contact problems with freeform surfaces : a knee joint 3D-study

One of the biomechanical roles of the knee joint is to withstand high loading forces. Thus, this articulation is quite susceptible to injuries and diseases, which may cause anomalous contact loads, asymmetrical gait patterns and local pain that, ultimately, leads to a knee replacement. In view of that, identifying and quantifying the loads placed on the human knee is critical for understanding realistic joint mechanics. Since there is no standard non-invasive experimental approach able to measure in vivo knee dynamic loads, such quantities have to be predicted by making use of computational methods. The efficiency of these computational methods is a primary concern for a contact formulation to be used in multibody system (MBS) dynamics. In fact, it has been recognized by many researchers that most of the time consumed in simulating contact phenomena is spent on the contact detection phase. This computational time motivated the development of an efficient methodology to predict the contact forces that is here presented.Fundação para a Ciência e a Tecnologia (FCT) - DACHOR (MIT-Pt/BSHHMS/ 0042/2008), BIOJOINTS (PTDC/EME-PME/ 099764/2008), SFRH/BD/40164/ 2007, SFRH/BD/47750/200

Techniques of intestinal transplantation in rat

Two surgical models of intestinal transplantation in the rat are described. One is the implantation of fetal and newborn intestine as free grafts into the omentum of adult recipients, the other the adult intestine transplantation as an accessory graft using vascular anastomoses. A hundred and sixteen small-bowel transplantations were done; 36 of which were fetal intestine (group I), 40 of newborn intestine (group II), and 40 of adult intestine (group III). In the fetal and newborn intestinal transplantation, we emphasize the practices that allowed us to avoid ischemic and traumatic injury to the graft. In the adult intestine transplantation with vascular anastomoses, we heighten the modifications in the surgical technique that made the operation easier and the strategies used to prevent hypothermia and hypovolemic shock. Once experienced with the two chosen surgical techniques, transplantation using an avascular segment became much easier and quicker than transplantation with vascular anastomoses. © 1998 Wiley-Liss, Inc. MICROSURGERY 18:424-429, 199

Hydrodynamics and water quality modelling in a regulated river segment: application on the instream flow definition

The aim of this paper is to present a global study on the hydrodynamics, water quality and their influence on aquatic fauna. The case study was conducted on a segment of the Lima river (North Portugal), downstream of the Touvedo dam, which was mainly constructed for hydroelectric power production.http://www.sciencedirect.com/science/article/B6VBS-4BHVGYD-7/1/7765917f49c0a6b3764cf34a8227cfc

Comparing parallel algorithms for van der waals energy with cell-list technique for protein structure prediction / Comparando algoritmos paralelos para energia de van der waals com técnica de lista de células para predição de estrutura de proteína

The discovery of the structure of a protein is a difficult and expensive task, because it requires minimizing different energies related to them. The van der Waals energy hás the most expensive evaluation in this context, and computational methods have been developed in this way, such as Genetic Algorithm (GA) and cell-list technique, which reduces its the complexity from O(n2) to O(n). Even with the support of GA and cell lists, the van der Waals energy evaluation still requires a long computing time, even for a small protein. Parallel Computing is capable to reduce the runtime to predict the structure of proteins. Parallel algorithms in such context are usually specific for one programming model and computer architecture, resulting in limited speedups. This paper compares the runtime of three distinct parallel algorithms for the evaluation of an ab initio and full-atom approach based on GA and cell-list technique, in order to minimize the van der Waals energy. The three parallel algorithms are in C and use one of these programming models: MPI, OpenMP or hybrid (MPI+Open MP). Our results show that van der Waals Energy are executed faster and with better speedups when using hybrid and more flexible parallel algorithms to predict the structure of larger proteins. We also show that for small proteins the communication of MPI imposes a high overhead for the parallel execution and, thus the Open MP presents a better relation cost x benefit in such cases

Close companions around young stars

Multiplicity is a fundamental property that is set early during stellar lifetimes, and it is a stringent probe of the physics of star formation. The distribution of close companions around young stars is still poorly constrained by observations. We present an analysis of stellar multiplicity derived from APOGEE-2 spectra obtained in targeted observations of nearby star-forming regions. This is the largest homogeneously observed sample of high-resolution spectra of young stars. We developed an autonomous method to identify double lined spectroscopic binaries (SB2s). Out of 5007 sources spanning the mass range of $\sim$0.05--1.5 \msun, we find 399 binaries, including both RV variables and SB2s. The mass ratio distribution of SB2s is consistent with a uniform for $q0.95$. The period distribution is consistent with what has been observed in close binaries ($<10$ AU) in the evolved populations. Three systems are found to have $q\sim$0.1, with a companion located within the brown dwarf desert. There are not any strong trends in the multiplicity fraction (MF) as a function of cluster age from 1 to 100 Myr. There is a weak dependence on stellar density, with companions being most numerous at $\Sigma_*\sim30$ stars/pc$^{-2}$, and decreasing in more diffuse regions. Finally, disk-bearing sources are deficient in SB2s (but not RV variables) by a factor of $\sim$2; this deficit is recovered by the systems without disks. This may indicate a quick dispersal of disk material in short-period equal mass systems that is less effective in binaries with lower $q$.Comment: 25 pages, 20 figures. Accepted to A

Colloidal nanomaterials for water quality improvement and monitoring

Water is the most important resource for all kind forms of live. It is a vital resource distributed unequally across different regions of the globe, with populations already living with water scarcity, a situation that is spreading due to the impact of climate change. The reversal of this tendency and the mitigation of its disastrous consequences is a global challenge posed to Humanity, with the scientific community assuming a major obligation for providing solutions based on scientific knowledge. This article reviews literature concerning the development of nanomaterials for water purification technologies, including collaborative scientific research carried out in our laboratory (nanoLAB@UA) framed by the general activities carried out at the CICECO-Aveiro Institute of Materials. Our research carried out in this specific context has been mainly focused on the synthesis and surface chemical modification of nanomaterials, typically of a colloidal nature, as well as on the evaluation of the relevant properties that arise from the envisaged applications of the materials. As such, the research reviewed here has been guided along three thematic lines: 1) magnetic nanosorbents for water treatment technologies, namely by using biocomposites and graphite-like nanoplatelets; 2) nanocomposites for photocatalysis (e.g., TiO2/Fe3O4 and POM supported graphene oxide photocatalysts; photoactive membranes) and 3) nanostructured substrates for contaminant detection using surface enhanced Raman scattering (SERS), namely polymers loaded with Ag/Au colloids and magneto-plasmonic nanostructures. This research is motivated by the firm believe that these nanomaterials have potential for contributing to the solution of environmental problems and, conversely, will not be part of the problem. Therefore, assessment of the impact of nanoengineered materials on eco-systems is important and research in this area has also been developed by collaborative projects involving experts in nanotoxicity. The above topics are reviewed here by presenting a brief conceptual framework together with illustrative case studies, in some cases with original research results, mainly focusing on the chemistry of the nanomaterials investigated for target applications. Finally, near-future developments in this research area are put in perspective, forecasting realistic solutions for the application of colloidal nanoparticles in water cleaning technologies.publishe

Hypermoduli Stabilization, Flux Attractors, and Generating Functions

We study stabilization of hypermoduli with emphasis on the effects of generalized fluxes. We find a class of no-scale vacua described by ISD conditions even in the presence of geometric flux. The associated flux attractor equations can be integrated by a generating function with the property that the hypermoduli are determined by a simple extremization principle. We work out several orbifold examples where all vector moduli and many hypermoduli are stabilized, with VEVs given explicitly in terms of fluxes.Comment: 45 pages, no figures; Version submitted to JHE

The water supply system as a potential source of fungal infection in paediatric haematopoietic stem cell units

Background: We conducted a prospective study to investigate the presence of microfungal contamination in the water supply system of the Oncology Paediatric Institute, São Paulo - Brazil after the occurrence of one invasive Fusarium solani infection in a patient after Haematopoietic Stem Cell Transplantation (HSCT). During a twelve-month period, we investigated the water supply system of the HSCT unit by monitoring a total of fourteen different collection sites.Methods: One litre of water was collected in each location, filtered through a 0.45 mu m membrane and cultured on SDA to detect the presence of filamentous fungi. Physicochemical analyses of samples were performed to evaluate the temperature, turbidity, pH, and the concentration of free residual chlorine.Results: Over the 12 months of the study, 164 samples were collected from the water supply system of the HSCT unit, and 139 of the samples tested positive for filamentous fungi (84.8%), generating a total of 2,362 colonies. Cladosporium spp., Penicillium spp., Purpureocillium spp. and Aspergillus spp. were ranked as the most commonly found genera of mould in the collected samples. of note, Fusarium solani complex isolates were obtained from 14 out of the 106 samples that were collected from tap water (mean of 20 CFU/L). There was a positive correlation between the total number of fungal CFU obtained in all cultures and both water turbidity and temperature parameters. Our findings emphasise the need for the establishment of strict measures to limit the exposure of high-risk patients to waterborne fungal propagules.Conclusions: We were able to isolate a wide variety of filamentous fungi from the water of the HSCT unit where several immunocompromised patients are assisted.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal de São Paulo, Dept Med, Disciplina Infectol, BR-04024002 São Paulo, BrazilUniv Austral Chile, Inst Clin Microbiol, Valdivia, ChileUniv Antofagasta, Antofagasta, ChileUniversidade Federal de São Paulo, Inst Oncol Pediat, GRAACC, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Med, Disciplina Infectol, BR-04024002 São Paulo, BrazilUniversidade Federal de São Paulo, Inst Oncol Pediat, GRAACC, BR-04023062 São Paulo, BrazilFAPESP: 2005/02138-3CNPq: 133621/2007-3CAPES: PNPD 2312/2011CNPq: 150368/2005-4Web of Scienc

Toxic Epidermal Necrolysis after Pemetrexed and Cisplatin for Non-Small Cell Lung Cancer in a Patient with Sharp Syndrome

Background: Pemetrexed is an antifolate drug approved for maintenance and second-line therapy, and, in combination with cisplatin, for first-line treatment of advanced nonsquamous non-small cell lung cancer. The side-effect profile includes fatigue, hematological and gastrointestinal toxicity, an increase in hepatic enzymes, sensory neuropathy, and pulmonary and cutaneous toxicity in various degrees. Case Report: We present the case of a 58-year-old woman with history of Sharp's syndrome and adenocarcinoma of the lung, who developed toxic epidermal necrolysis after the first cycle of pemetrexed, including erythema, bullae, extensive skin denudation, subsequent systemic inflammation and severe deterioration in general condition. The generalized skin lesions occurred primarily in the previous radiation field and responded to immunosuppressive treatment with prednisone. Conclusion: Although skin toxicity is a well-known side effect of pemetrexed, severe skin reactions after pemetrexed administration are rare. Caution should be applied in cases in which pemetrexed is given subsequent to radiation therapy, especially in patients with pre-existing skin diseases