155 research outputs found
Produtividade de trigo e soja em Latossolo Vermelho distrófico sob erosão simulada e causada pela chuva.
Avaliação de agrotóxico em alface (Lactuca sativa L.) produzida na região do Distrito Federal.
Parallel neural network recognition - a multi-agent system approach
This paper presents and discusses the design and the development of a pattern recognition agent based on neural networks. This agent is part of an intelligent navigation system, providing it with the necessary vision abilities so that it can be placed on a strange environment in order to explore and recognise its structures and specificities. Although similar, the properties of the recognised objects change through time and according to each specific environment. The flexibility required by such recognition process was implemented by several pattern recognition agents. Each agent is based on a neural network and can be trained on-line by a parallel training algorithm to allow an effective real time utilisation
A Novel Biomanufacturing System to Produce Multi-Material Scaffolds for Tissue Engineering: Concept and Preliminary Results
This research work aims to validate a new system that enables the fabrication of multimaterial 3D structures using poly(e-caprolactone) and sodium alginate for potential use in Tissue Engineering applications. To produce multi-material scaffolds for Tissue Engineering, accurate techniques are needed to obtain three-dimensional constructs with clinically appropriate size and structural integrity. This paper presents a novel biomanufacturing system which can fabricate 3D scaffolds with precise shape and porosity, through the control of all fabrication modules by an integrated computational platform. The incorporation of a clean flow unit and a camera makes it possible to produce scaffolds in a clean environment and provides a monitoring tool to analyse
constructs during the production, respectively.info:eu-repo/semantics/publishedVersio
Ovarian Ectopic Pregnancy in Adolescence
Ovarian pregnancy is one of the rarest types of extrauterine pregnancy. Its preoperative diagnosis remains a challenge since it presents quite similarly to tubal pregnancy and complicated ovarian cysts. Although in most cases, histology is necessary to confirm the diagnosis, we present an ovarian pregnancy in a teenager, correctly diagnosed during ultrasound examination
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Interventions to prevent urinary catheter-associated infections in children and neonates: a systematic review.
INTRODUCTION: Few data are available to inform strategies for the prevention of catheter-associated urinary tract infection (CAUTI) in children and neonates. Many recommendations are derived from studies in adults and cannot be applied to the paediatric population. OBJECTIVE: This study was aimed to identify all studies that measured the efficacy of an intervention for the prevention of CAUTI in children and neonates. METHODS: A systematic review using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) was conducted. Eligible studies published between January 1st, 1995 and December 31st, 2017, were identified in PubMed, the Cochrane Database of Systematic Reviews, LILACS, SciELO and DOAJ if applying an intervention with the aim of CAUTI prevention in inpatient children, infants or neonates. The following study designs were included: controlled and non-controlled before-and-after studies, (controlled) interrupted time series analyses and randomized controlled trials. Quantitative or qualitative studies on interventions in both adults and children were eligible if data on children could be extracted. Reviews, case series, letters, notes, conference abstracts and opinion articles were excluded. RESULTS: Of 99 articles identified, six were included in the final analysis, after consensus from three independent investigators. Four studies used a multimodal strategy (using at least four or more different components at the same time) as follows: aseptic rules during catheter insertion and removal; cleaning the urethral meatus with sterile water; use of a new silicone catheter per insertion with a closed sterile drainage system by a sterile technique; daily evaluation of catheter requirement; placement of indwelling urinary catheters only for approved indications; reducing of urinary catheter days and positioning of the patient and collection device to assist in urine drainage. One study tested periurethral cleaning intervention to reduce CAUTI. One study described the association of the presence of a physician safety champion with urinary catheter device utilization ratios. Catheter-associated UTI reduction rates were reported in four studies; three achieved statistically significant decreases in CAUTI rates. Positive results were achieved only when a multimodal strategy was used with at least four or more components. This strategy could be adopted for paediatric healthcare institutions to reduce CAUTI rates in children and neonates. CONCLUSION: Evidence exists to support the use of a multimodal strategy for CAUTI reduction in hospitalized children and neonates
Traffic Vertical Signposting: Materials Characterization and Structural Numerical Simulation
Aknowlegements:
This work was supported by the project POCI-01-0247-FEDER-010797from the Agency for Competitiveness and Innovation (IAPMEI). In addition, the authors acknowledge the funding from the project UID/Multi/04044/2013 of the Portuguese Foundation for Science and Technology (FCT) and PAMI - ROTEIRO/0328/2013 (Nº 022158).The existing metallic solutions used for vertical traffic signs are associated with higher
costs and environmental issues due to their manufacturing and degradation, when compared with polymeric solutions. Thus, the development of vertical signs considering the injection from polymeric materials in order to overcome problems related with sustainability, maintenance costs, and to achieve higher resistance to corrosion assumes nowadays an important role. The use of ecofriendly and innovative products considering the industrial waste combined with synthetic polymers performing the appropriate mechanical properties, can also be studied to find out new solutions that
allow to solve the aforementioned problems. Additionally, these innovative vertical signs can contribute to avoid vandalism events related with theft and graffiti activities. This work presents the prior materials investigation and the structural design of vertical signs that are intended to be produced through polymer injection. Three main steps were considered: i) materials research, ii) materials characterisation through the analysis of polycarbonate resin isolated and in different sets of mixtures with different concentrations through tensile testing and static water contact angle measurements to find the optimal material composition; and iii) structural numerical simulation considering polycarbonate resin and using the current standard EN 12899-1 [1] to compute wind resistance, temporary and permanent deflections. Both experimental and numerical results led to an optimized proposal of the vertical signposting structural design.info:eu-repo/semantics/publishedVersio
The Use of Polypropylene and High-Density Polyethylene on Cork Plastic Composites for Large Scale 3D Printing
Acknowledgements This work is supported by the Fundação para a Ciência e a Tecnologia (FCT) and Centro2020 through the Project references: UID/Multi/04044/2013 and PAMI - ROTEIRO/0328/2013 (Nº 022158). In addition, the authors acknowledge the funding from the project World of Outstanding Wool and Wood (WOWW), POCI-01-0247-FEDER-017574 from the Portuguese National Innovation Agency. The authors gratefully acknowledge to Amorim Cork Composites for the cork powder. We thank Ana O. Tojeira and Ana R. Fonseca for the support provided in performing the laboratorial tests as Laboratory Managing Engineers.This work focuses on studying the possibility of 3D printing of composite materials
composed by cork and a polymer matrix (CPC). Initially the cork was mixed with two types of polymers (HDPE and PP) in different proportions and later processed using extrusion and injection. The composites were tested to study the physical, chemical and mechanical properties. The material was then tested on a large-scale 3D printer to study its feasibility and the ability to produce new products through 3D printing. Attention was focused on the use of pure cork, varying the concentration of cork and coupling agent in thermoplastic matrix composites of PP and HDPE. It was demonstrated that the increase of 5wt.% of coupling agent in the two types of polymers
significantly improved the mechanical properties and adhesion between the phases but the increase
in cork concentration decreased mechanical properties and crystallinity. The CPCs with PP showed
to have better mechanical properties, better aesthetic and internal structural quality, and easier
processability than those with HDPE matrix. Nevertheless, the HDPE CPCs showed a high degree
of crystallization.
Concerning 3D printing, it was demonstrated the possibility of making new products based on
natural cork fibers, showing promising results, although additional research is still needed to
optimize the process.info:eu-repo/semantics/publishedVersio
Effect of Tween-80 on Stability and Secretion of Hydrophobic Tagged-cutinases
To significantly enhance the downstream processing, two cutinase variants were constructed by genetic fusion small hydrophobic peptides (WP)2 and (WP)4, respectively. However, the fusion of these peptides impairs cutinase secretion by the host cell
Saccharomyces cerevisiae and increases cutinase inactivation in the culture broth due to cutinase aggregation, resulting in cutinase activities per biomass of 56 % of cutinase-(WP)2 and of 7 % of cutinase-(WP)4, in relation to cutinase without the hydrophobic tags. It was observed that the addition of non-ionic surfactant Tween-80 into the culture broth could minimise the cutinase inactivation. The addition of Tween-80 also results in the enhancement of cutinase secretion by the yeast cell, leading to 1.25 and 2.51 fold-higher extracellular cutinase-(WP)2 and cutinase-(WP)4, respectively, in relation to cultivations performed in the absence of surfactant. Therefore, the addition of Tween-80 on the culture broth partly minimises the effect of fusion of the hydrophobic tags on the
inactivation of the enzymatic activity and on the reduction of the protein secretion. By this way, the use of Tween-80 on the S. cerevisiae cultivation may contribute to the efficiency enhancement of the downstream processing of tagged cutinases
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