Relação entre a unidade de biofeedback de pressão, deslocamento do centro de pressão e atividade eletromiográfica durante o active straight leg raising em indivíduos com e sem dor lombo-pélvica.

Introdução: A unidade de biofeedback de pressão, em indivíduos com dor lombo-pélvica, é utilizada durante exercícios de estabilização segmentar, no entanto ainda carece de evidência científica. Objetivo: Determinar a relação entre a unidade de biofeedback de pressão (UBFP), o deslocamento do centro de pressão no sentido médio-lateral (COPml) e a atividade eletromiográfica abdominal durante o active straight leg raising (ASLR) em indivíduos com e sem dor lombo-pélvica, bem como identificar diferenças entre os grupos. Metodologia: Estudo transversal analítico em 18 estudantes universitários voluntários com dor lombo-pélvica crónica inespecífica (GCD) e em 20 sem dor (GSD). Durante o ASLR (desafio postural dinâmico) foram avaliadas as variações máxima e média da pressão (recorrendo à UBFP) e do deslocamento do COPml (através da plataforma de forças), bem como a atividade muscular abdominal, bilateralmente, com recurso à eletromiografia de superfície. Estatisticamente recorreu-se à correlação de Spearman e ao teste Mann-Whitney U, ambos com um nível de significância de 0,05. Resultados: No GCD, ao contrário do GSD, não foi verificada uma relação entre a UBFP e a atividade do transverso abdominal/obliquo interno (TrA/OI) contra-lateral. Correlações moderadas, mas com sentidos opostos, foram evidenciadas em ambos os grupos, entre o deslocamento do COPml e a atividade do TrA/OI contra-lateral. Em ambos os grupos, a UBFP demonstrou estar fortemente correlacionada com o COPml. Não foram observadas diferenças significativas entre os grupos nas variáveis avaliadas. Conclusão: A UBFP, no GCD, não se apresentou relacionada com a atividade do TrA/OI. Contudo, demonstrou uma relação com o deslocamento do COPml, em ambos os grupos, sendo portanto um indicador de estabilidade do tronco e assim, uma ferramenta útil em ambiente clínico. No GCD observou-se que uma maior atividade muscular TrA/OI pressupõe maior deslocamento do COPml, sendo uma relação contrária à verificada no GSD, podendo ser um indicador da perda da sua ação tónica.

Development of electrochemical methods for determination of tramadol - analytical application to pharmaceutical dosage forms

A square-wave voltammetric (SWV) method and a flow injection analysis system with amperometric detection were developed for the determination of tramadol hydrochloride. The SWV method enables the determination of tramadol over the concentration range of 15-75 µM with a detection limit of 2.2 µM. Tramadol could be determined in concentrations between 9 and 50 µM at a sampling rate of 90 h-1, with a detection limit of 1.7 µM using the flow injection system. The electrochemical methods developed were successfully applied to the determination of tramadol in pharmaceutical dosage forms, without any pre-treatment of the samples. Recovery trials were performed to assess the accuracy of the results; the values were between 97 and 102% for both methods.

Determination of pesticides in fruit and fruit juices by chromatographic methods. An overview

In order to combat a variety of pests, pesticides are widely used in fruits. Several extraction procedures (liquid extraction, single drop microextraction, microwave-assisted extraction, pressurized liquid extraction, supercritical fluid extraction, solid-phase extraction, solid-phase microextraction, matrix solid-phase dispersion, and stir bar sorptive extraction) have been reported to determine pesticide residues in fruits and fruit juices. The significant change in recent years is the introduction of the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) methods in these matrices analysis. A combination of techniques reported the use of new extraction methods and chromatography to provide better quantitative recoveries at low levels. The use of mass spectrometric detectors in combination with liquid and gas chromatography has played a vital role to solve many problems related to food safety. The main attention in this review is on the achievements that have been possible because of the progress in extraction methods and the latest advances and novelties in mass spectrometry, and how these progresses have influenced the best control of food, allowing for an increase in the food safety and quality standards.

Electrochemical methods in pesticides control

The state of the art of voltammetric and amperometric methods used in the study and determination of pesticides in crops, food, phytopharmaceutical products, and environmental samples is reviewed. The main structural groups of pesticides, i.e., triazines, organophosphates, organochlorides, nitrocompounds, carbamates, thiocarbamates, sulfonylureas, and bipyridinium compounds are considered with some degradation products. The advantages, drawbacks, and trends in the development of voltammetric and amperometric methods for study and determination of pesticides in these samples are discussed.

Evaluation of distinct input methods of an intelligent wheelchair in simulated and real environments: a performance and usability study

This paper focuses on evaluating the usability of an Intelligent Wheelchair (IW) in both real and simulated environments. The wheelchair is controlled at a high-level by a flexible multimodal interface, using voice commands, facial expressions, head movements and joystick as its main inputs. A Quasi-experimental design was applied including a deterministic sample with a questionnaire that enabled to apply the System Usability Scale. The subjects were divided in two independent samples: 46 individuals performing the experiment with an Intelligent Wheelchair in a simulated environment (28 using different commands in a sequential way and 18 with the liberty to choose the command); 12 individuals performing the experiment with a real IW. The main conclusion achieved by this study is that the usability of the Intelligent Wheelchair in a real environment is higher than in the simulated environment. However there were not statistical evidences to affirm that there are differences between the real and simulated wheelchairs in terms of safety and control. Also, most of users considered the multimodal way of driving the wheelchair very practical and satisfactory. Thus, it may be concluded that the multimodal interfaces enables very easy and safe control of the IW both in simulated and real environments.

Local fractional variational iteration and decomposition methods for wave equation on cantor sets within local fractional operators

We perform a comparison between the fractional iteration and decomposition methods applied to the wave equation on Cantor set. The operators are taken in the local sense. The results illustrate the significant features of the two methods which are both very effective and straightforward for solving the differential equations with local fractional derivative.

Classification of some penalty methods

Optimization problems arise in science, engineering, economy, etc. and we need to find the best solutions for each reality. The methods used to solve these problems depend on several factors, including the amount and type of accessible information, the available algorithms for solving them, and, obviously, the intrinsic characteristics of the problem. There are many kinds of optimization problems and, consequently, many kinds of methods to solve them. When the involved functions are nonlinear and their derivatives are not known or are very difficult to calculate, these methods are more rare. These kinds of functions are frequently called black box functions. To solve such problems without constraints (unconstrained optimization), we can use direct search methods. These methods do not require any derivatives or approximations of them. But when the problem has constraints (nonlinear programming problems) and, additionally, the constraint functions are black box functions, it is much more difficult to find the most appropriate method. Penalty methods can then be used. They transform the original problem into a sequence of other problems, derived from the initial, all without constraints. Then this sequence of problems (without constraints) can be solved using the methods available for unconstrained optimization. In this chapter, we present a classification of some of the existing penalty methods and describe some of their assumptions and limitations. These methods allow the solving of optimization problems with continuous, discrete, and mixing constraints, without requiring continuity, differentiability, or convexity. Thus, penalty methods can be used as the first step in the resolution of constrained problems, by means of methods that typically are used by unconstrained problems. We also discuss a new class of penalty methods for nonlinear optimization, which adjust the penalty parameter dynamically.

Damage evaluation of drilled carbon/epoxy laminates based on area assessment methods

The characteristics of carbon fibre reinforced laminates had widened their use, from aerospace to domestic appliances. A common characteristic is the need of drilling for assembly purposes. It is known that a drilling process that reduces the drill thrust force can decrease the risk of delamination. In this work, delamination assessment methods based on radiographic data are compared and correlated with mechanical test results (bearing test).

A web-based tool to evaluate the iterative processes of direct search methods

Constrained and unconstrained Nonlinear Optimization Problems often appear in many engineering areas. In some of these cases it is not possible to use derivative based optimization methods because the objective function is not known or it is too complex or the objective function is non-smooth. In these cases derivative based methods cannot be used and Direct Search Methods might be the most suitable optimization methods. An Application Programming Interface (API) including some of these methods was implemented using Java Technology. This API can be accessed either by applications running in the same computer where it is installed or, it can be remotely accessed through a LAN or the Internet, using webservices. From the engineering point of view, the information needed from the API is the solution for the provided problem. On the other hand, from the optimization methods researchers’ point of view, not only the solution for the problem is needed. Also additional information about the iterative process is useful, such as: the number of iterations; the value of the solution at each iteration; the stopping criteria, etc. In this paper are presented the features added to the API to allow users to access to the iterative process data.

Direct-search penalty/barrier methods

In Nonlinear Optimization Penalty and Barrier Methods are normally used to solve Constrained Problems. There are several Penalty/Barrier Methods and they are used in several areas from Engineering to Economy, through Biology, Chemistry, Physics among others. In these areas it often appears Optimization Problems in which the involved functions (objective and constraints) are non-smooth and/or their derivatives are not know. In this work some Penalty/Barrier functions are tested and compared, using in the internal process, Derivative-free, namely Direct Search, methods. This work is a part of a bigger project involving the development of an Application Programming Interface, that implements several Optimization Methods, to be used in applications that need to solve constrained and/or unconstrained Nonlinear Optimization Problems. Besides the use of it in applied mathematics research it is also to be used in engineering software packages.

A comparative analysis of fault injection methods via enhanced on-chip debug infrastructures

On-chip debug (OCD) features are frequently available in modern microprocessors. Their contribution to shorten the time-to-market justifies the industry investment in this area, where a number of competing or complementary proposals are available or under development, e.g. NEXUS, CJTAG, IJTAG. The controllability and observability features provided by OCD infrastructures provide a valuable toolbox that can be used well beyond the debugging arena, improving the return on investment rate by diluting its cost across a wider spectrum of application areas. This paper discusses the use of OCD features for validating fault tolerant architectures, and in particular the efficiency of various fault injection methods provided by enhanced OCD infrastructures. The reference data for our comparative study was captured on a workbench comprising the 32-bit Freescale MPC-565 microprocessor, an iSYSTEM IC3000 debugger (iTracePro version) and the Winidea 2005 debugging package. All enhanced OCD infrastructures were implemented in VHDL and the results were obtained by simulation within the same fault injection environment. The focus of this paper is on the comparative analysis of the experimental results obtained for various OCD configurations and debugging scenarios.

Gestão de resíduos produzidos num sistema de drenagem e tratamento de águas residuais

O presente trabalho centra-se na gestão de resíduos produzidos no sistema de drenagem e tratamento de águas residuais do município de Vila Nova de Gaia. A entidade onde decorreu o trabalho é uma empresa responsável pela distribuição de água e pela drenagem e tratamento de águas residuais. A empresa está certificada pela norma NP EN ISO 14001, desde 2001, sendo então um dos objectivos o enquadramento da gestão dos resíduos em estudo na referida norma, acompanhando os requisitos da mesma com vista ao seu total cumprimento. Outros dos objectivos foi estudar qual a opção de tratamento mais adequada a aplicar ao resíduo no seu local de armazenamento temporário com vista a minorar os seus impactes ambientais. De acordo com a caracterização analítica do resíduo e com os aspetos legais aplicáveis, foram também analisados os destinos finais possíveis e ambientalmente adequados ao resíduo. A medida proposta para a minimização de impactes no local de armazenamento temporário do resíduo foi a estabilização com cal nos leitos de secagem, disponíveis numa antiga ETAR de loteamento. O doseamento de cal a aplicar ao resíduo será de 10 kg de cal apagada comercial (Ca (OH)2) por uma tonelada de resíduo fresco com um período mínimo de secagem de 2 meses. Outra das medidas de minimização de impactes selecionada foi a implantação de uma cortina arbórea ao redor da instalação. Sendo o resíduo em estudo muito heterogéneo, constituído principalmente por areias, terras e gradados, a valorização foi equacionada mas não foram encontrados alternativas viáveis. O destino final considerado como mais adequado tendo em conta todas as características do resíduo e eluato, analisadas de acordo com o previsto no Decreto-Lei n.º 183/2009 de 10 de Agosto, foi o aterro para resíduos não perigosos. Foi também objecto do estudo a identificação e análise de todos os aspectos ambientais relacionados com a gestão de resíduos e a avaliação da sua significância. Dos aspectos ambientais identificados como significativos, destacam-se aqueles que ocorrem presentemente, os resíduos armazenados (gradados/limpeza de redes), e os que podem ocorrer em situações de emergência, fuga/derrame de óleos/combustíveis e cheiros/odores. De forma a minimizar os aspectos ambientais identificados, e de acordo com a norma NP EN ISO 14001, foram propostas ações que constam de um programa de gestão elaborado para este trabalho, onde se definem os objectivos, metas e prazos. As principais medidas propostas no programa de gestão foram: Estabilização com cal (inicial e reforço se necessário); melhoria do espaço envolvente; análise de questões de saúde ocupacional/segurança; adjudicação de prestação de serviços da recolha por operador licenciado; implantação da cortina arbórea; registo no SIRAPA; criação de planos de emergência ambiental e de segurança.

Influência de diferentes estratégias de estabilização lombopélvica e de programas de exercícios de controlo motor no Active Straight Leg Raise

Introdução: O Active Straight Leg Raise (ASLR) tem sido sugerido como um indicador clínico da estabilidade lombopélvica. Estratégias passivas e ativas podem contribuir para aumentar esta estabilidade, assim como programas de exercício baseados nas mesmas estratégias ativas. Objetivos: Comparar os efeitos imediatos da compressão pélvica manual (CP), do drawing-in (DI) e do bracing abdominal (BA) durante o ASLR em indivíduos com e sem dor lombopélvica crónica e inespecífica, e avaliar o efeito prolongado das manobras de estabilização ativas através dos programas de exercícios de controlo motor, Pilates e McGill. Métodos: Estudo transversal, com uma amostra de 111 voluntários, 52 sem dor lombopélvica (NLPPG) e 59 com dor lombopélvica (LPPG), e estudo experimental, formado pelo LPPG dividido em 19 no grupo controlo (GC), 20 no grupo pilates (GP) e 20 no grupo mcgill (GMg). Foi avaliado o ASLR padrão, o ASLR com CP, o ASLR com DI e ASLR com BA. Os participantes foram avaliados antes e após as 8 semanas de implementação dos programas exercícios de McGill e Richardson, apenas aos respetivos grupos. Resultados: O LPPG apresentou significativamente maior score no ASLR comparativamente ao NLPPG (z=-9,361; p<0,001). Apesar do BA ter apresentado scores inferiores às restantes estratégias (p<0,001), todas elas foram capazes de diminuir o score do ASLR (p<0,001). Após a aplicação dos programas de exercícios, verificou-se que o GP (p<0,001) e o GMg (p<0,001) apresentaram scores significativamente menores no ASLR, relativamente ao GC. No GP e no GMg verificou-se uma diminuição do score do ASLR (Z=-4,028; p<0,001; Z=-4,179; p<0,001, respetivamente). Além disso, GMg apresentou uma tendência para apresentar menores scores do ASLR comparativamente ao GP. Conclusão: Qualquer uma destas manobras de estabilização quando adicionada ao ASLR pode aumentar a estabilidade lombopélvica, especialmente o BA. Os exercícios de Pilates e de McGill permitiram melhorar os scores do ASLR.

Adapted Control Methods for Cerebral Palsy Users of an Intelligent Wheelchair

The development of an intelligent wheelchair (IW) platform that may be easily adapted to any commercial electric powered wheelchair and aid any person with special mobility needs is the main objective of this project. To be able to achieve this main objective, three distinct control methods were implemented in the IW: manual, shared and automatic. Several algorithms were developed for each of these control methods. This paper presents three of the most significant of those algorithms with emphasis on the shared control method. Experiments were performed by users suffering from cerebral palsy, using a realistic simulator, in order to validate the approach. The experiments revealed the importance of using shared (aided) controls for users with severe disabilities. The patients still felt having complete control over the wheelchair movement when using a shared control at a 50% level and thus this control type was very well accepted. Thus it may be used in intelligent wheelchairs since it is able to correct the direction in case of involuntary movements of the user but still gives him a sense of complete control over the IW movement.