A high-throughput screening method for general cytotoxicity part I Chemical toxicity

Foi desenvolvido um m��todo destinado a fazer a triagem r��pida e o escalonamento da toxicidade geral exercida por xenobi��ticos tendo como modelo o Saccharomyces cerevisiae. Para padronizar as condi����es de experimenta����o foi estabelecida a rela����o entre a absorv��ncia a 525 nm e o n��mero de c��lulas em suspens��o por mililitro de meio de cultura e calculadas uma curva padr��o e respectiva equa����o definidora (Y=6,8219E-08X + 0,0327) Culturas de Saccharomyces cerevisiae em meio completo para leveduras (YPD - 1% de glucose 2%, de peptona 0,5% e extracto de levedura 1%) foram expostas a diferentes concentra����es de nicotina e a inibi����o do crescimento avaliada.

A efic��cia do exame telerradiogr��fico de t��rax como t��cnica de "screening" em popula����o hospitalar

�� analisada a efic��cia da telerradiograf��a de t��rax como t��cnica de "screening" em popula����o hospitalar. Utilizando-se uma t��cnica prospectiva n��o concorrente, �� evidenciado que pouco benef��cio traz ao paciente a chapa de t��rax AP na interna����o, na primeira consulta ou no pr��-operat��rio em geral. Para sete em cada 100 pacientes foi diagnosticado importante patologia assintom��tica. Nenhum paciente entre 0 e 19 anos teve anormalidade evidenciada pela chapa. Recomenda-se, para esta faixa, a elimina����o do exame, e para pacientes acima de 20 anos a introdu����o da abreugrafia, ao inv��s da telerradiografia de t��rax.

Diagnostic performance of visual screening tests in the elderly

This study aimed to determine and evaluate the diagnostic accuracy of visual screening tests for detecting vision loss in elderly. This study is defined as study of diagnostic performance. The diagnostic accuracy of 5 visual tests -near convergence point, near accommodation point, stereopsis, contrast sensibility and amsler grid���was evaluated by means of the ROC method (receiver operating characteristics curves), sensitivity, specificity, positive and negative likelihood ratios (LR+/LR���). Visual acuity was used as the reference standard. A sample of 44 elderly aged 76.7 years (��9.32), who were institutionalized, was collected. The curves of contrast sensitivity and stereopsis are the most accurate (area under the curves were 0.814���p = 0.001, C.I.95%[0.653;0.975]��� and 0.713���p = 0.027, C.I.95%[0,540;0,887], respectively). The scores with the best diagnostic validity for the stereopsis test were 0.605 (sensitivity 0.87, specificity 0.54; LR+ 1.89, LR���0.24) and 0.610 (sensitivity 0.81, specificity 0.54; LR+1.75, LR���0.36). The scores with higher diagnostic validity for the contrast sensibility test were 0.530 (sensitivity 0.94, specificity 0.69; LR+ 3.04, LR���0.09). The contrast sensitivity and stereopsis test's proved to be clinically useful in detecting vision loss in the elderly.

Diagnostic performance of visual screening tests in the elderly

The aging of Portuguese population is characterized by an increase of individuals aged older than 65 years. Preventable visual loss in older persons is an important public health problem. Tests used for vision screening should have a high degree of diagnostic validity confirmed by means of clinical trials. The primary aim of a screening program is the early detection of visual diseases. Between 20% and 50% of older people in the UK have undetected reduced vision and in most cases is correctable. Elderly patients do not receive a systematic eye examination unless a problem arises with their glasses or suspicion vision loss. This study aimed to determine and evaluate the diagnostic accuracy of visual screening tests for detecting vision loss in elderly. Furthermore, it pretends to define the ability to find the subjects affected with vision loss as positive and the subjects not affected with the same disease as negative. The ideal vision screening method should have high sensitivity and specificity for early detection of risk factors. It should be also low cost and easy to implement in all geographic and socioeconomic regions. Sensitivity is the ability of an examination to identify the presence of a given disease and specificity is the ability of the examination to identify the absence of a given disease. It was not an aim of this study to detect abnormalities that affect visual acuity. The aim of this study was to find out what��s the best test for the identification of any vision loss.

Solid-state Marx based two-switch voltage modulator for the On-Line Isotope Mass Separator accelerator at the European Organization for Nuclear Research

A new circuit topology is proposed to replace the actual pulse transformer and thyratron based resonant modulator that supplies the 60 kV target potential for the ion acceleration of the On-Line Isotope Mass Separator accelerator, the stability of which is critical for the mass resolution downstream separator, at the European Organization for Nuclear Research. The improved modulator uses two solid-state switches working together, each one based on the Marx generator concept, operating as series and parallel switches, reducing the stress on the series stacked semiconductors, and also as auxiliary pulse generator in order to fulfill the target requirements. Preliminary results of a 10 kV prototype, using 1200 V insulated gate bipolar transistors and capacitors in the solid-state Marx circuits, ten stages each, with an electrical equivalent circuit of the target, are presented, demonstrating both the improved voltage stability and pulse flexibility potential wanted for this new modulator.

Mass- Radius Relation for Magnetized Strange Quarks Stars

We review the stability of magnetized strange quark matter (MSQM) within the phenomenological MIT bag model, taking into account the variation of the relevant input parameters, namely, the strange quark mass, baryon density, magnetic field and bag parameter. A comparison with magnetized asymmetric quark matter in beta-equilibrium as well as with strange quark matter (SQM) is presented. We obtain that the energy per baryon for MSQM decreases as the magnetic field increases, and its minimum value at vanishing pressure is lower than the value found for SQM, which implies that MSQM is more stable than non-magnetized SQM. The mass-radius relation for magnetized strange quark stars is also obtained in this framework.

In vitro toxicity screening of silica-coated superparamagnetic iron oxide nanoparticles in glial cells

Nanotechnology industry is progressing with prospects of substantial benefits to economics and science. Superparamagnetic iron oxide nanoparticles (ION) have been showing excellent magnetic properties, biocompatibility and biodegradability, broadening their potential applications and importance in the biomedical field

Survey of cyclopids (Crustacea, Copepoda) in Brazil and preliminary screening of their potential as dengue vector predators

INTRODUCTION: Cyclopid copepods are known to be good mosquito controllers, specially as regards the larvae of the dengue vectors Aedes aegypti and Ae. albopictus. MATERIAL AND METHOD: The objective of the study was to survey the local copepod fauna and search for new strains of M. longisetus var. longisetus, comparing the potential of the samples found with the current strain ML-01 against Ae. albopictus larvae, under laboratory conditions. Eleven bodies of water in Campinas, SP, Brazil, were screened for copepods by collecting 1.5 l of water from each of then. The predatory potential of adults copepods was evaluated over 24 h, in the laboratory, for groups of 5 individuals preying upon 30 first instar Ae. albopictus larvae. RESULTS AND CONCLUSION: The following cyclopid species were found: Metacyclops mendocinus, Tropocyclops prasinus, Eucyclops sp, Eucyclops serrulatus, Eucyclops solitarius, Eucyclops ensifer, Macrocyclops albidus var. albidus and Mesocyclops longisetus var. longisetus. The predatory potential of these copepods ranged from nil to 97.3%. A sample collected in the field containing only M. longisetus var. longisetus showed the best control efficiency with no significant difference from a three-year old laboratory culture (ML-01) of the same species evaluated for comparison. The sample with few M. albidus var. albidus was ranked in second place showing an average 25.9% efficiency. The use of copepods in trap tires as dengue vector controllers is discussed.

Rastreio neonatal dos d��fices do ciclo da ureia em Portugal

Os d��fices do ciclo da ureia s��o um grupo de doen��as heredit��rias do metabolismo caracterizadas fundamentalmente por uma acumula����o de am��nia. Clinicamente o espectro �� muito alargado, com formas de apresenta����o no per��odo neonatal at�� situa����es mais moderadas de apresenta����o tardia em adultos. O tratamento �� fundamentalmente de base nutricional e traduz-se numa redu����o significativa da mortalidade e morbilidade. Com a introdu����o da espectrometria de massa nos laborat��rios de rastreio neonatal em meados dos anos 90, passou a ser poss��vel quantificar alguns intermedi��rios do ciclo, o que associado �� exist��ncia de um intervalo livre e um tratamento eficaz, permitiu o rastreio de algumas das doen��as deste grupo. Em 2004 iniciou-se em Portugal o rastreio dos d��fices do ciclo da ureia, tendo-se rastreado at�� ao presente, 988 687 rec��m-nascidos e identificado 19 casos positivos. Recentes desenvolvimentos t��cnicos vieram possibilitar a quantifica����o de novos marcadores, mais concretamente do ��cido or��tico, o que abre a possibilidade de rastrear o d��fice em ornitina transcarbamilase, o d��fice do ciclo da ureia mais frequente. Os autores apresentam a situa����o atual do rastreio dos d��fices do ciclo da ureia e as perspetivas em virtude dos novos desenvolvimentos t��cnicos.

Rastreio neonatal da homocistin��ria cl��ssica revela uma elevada frequ��ncia da defici��ncia em MAT I/III na Pen��nsula Ib��rica

A homocistin��ria devida �� defici��ncia da enzima cistationina -sintetase ou ���homocistin��ria cl��ssica��� �� uma doen��a metab��lica rara (1/344 000 RN), de transmiss��o autoss��mica recessiva e caracterizada por elevada heterogeneidade cl��nica, que frequentemente contribui para o diagn��stico tardio. Existe tratamento efetivo, se institu��do antes de se instalarem sintomas irrevers��veis, pelo que tem sido inclu��da num n��mero consider��vel de programas de rastreio neonatal. O rastreio baseia-se na determina����o dos n��veis plasm��ticos de metionina, por espectrometria de massa em tandem (ms/ms), mas conduz �� identifica����o de muitos casos falsos-positivos, portadores de uma condi����o com significado cl��nico n��o completamente esclarecido, a defici��ncia em metionina adenosiltransferase (MAT I/III). Ambas as condi����es s��o rastreadas na Galiza e em Portugal desde 2000 e 2004, respetivamente. Desde ent��o, foram identificados tr��s doentes com homocistin��ria cl��ssica e 44 doentes com defici��ncia em MAT I/III. Uma forma dominante, e aparentemente benigna, desta ��ltima condi����o, associada �� muta����o p.R264H, parece ser muito frequente na Pen��nsula Ib��rica. A implementa����o de um teste de segunda linha, consistindo na determina����o da homociste��na total, permitiria reduzir consideravelmente o n��mero de RN identificados com defici��ncia em MAT I/III e melhorar a especificidade e valor positivo preditivo do rastreio da homocistin��ria cl��ssica.

Children visual screening protocol: validation by a focus group panel of experts

Screening programs, particularly the inclusion of specific orthoptic tests to detect visual abnormalities, varies among countries. This study aims to: 1) describes expert perception of issues related with children visual screening; 2) identify specific orthoptic tests to detect visual abnormalities in children visual screening.

Visual Screening Competencies Questionnaire (VSCQ) and orthoptic practice

The identification of core competencies which are important for undertaking accurate visual screening by orthoptists is considered in this study. The aim was to construct and validate a questionnaire for orthoptists to assess visual screening competency. This study comprised three steps. The first step involved a 69-item self-assessment questionnaire constructed to assess orthoptists' perception of their competencies in visual screening programs for children. This questionnaire was constructed with statements from the Orthoptic Benchmark Statement for Health Care Programmes (Quality Assurance Agency for Higher Education, UK) and included three competency dimensions: interpersonal (IP), instrumental (IT) and systemic (ST). The second step involved questionnaire translation.

Mass spectrometry improvement on an high current ion implanter

The development of accurate mass spectrometry, enabling the identification of all the ions extracted from the ion source in a high current implanter is described. The spectrometry system uses two signals (x-y graphic), one proportional to the magnetic field (x-axes), taken from the high-voltage potential with an optic fiber system, and the other proportional to the beam current intensity (y-axes), taken from a beam-stop. The ion beam mass register in a mass spectrum of all the elements magnetically analyzed with the same radius and defined by a pair of analyzing slits as a function of their beam intensity is presented. The developed system uses a PC to control the displaying of the extracted beam mass spectrum, and also recording of all data acquired for posterior analysis. The operator uses a LabView code that enables the interfacing between an I/O board and the ion implanter. The experimental results from an ion implantation experiment are shown. (C) 2011 Elsevier B.V. All rights reserved.

Avalia����o do risco cardiovascular global numa popula����o da zona Norte do Pa��s

As doen��as cardiovasculares lideram as causas de mortalidade em Portugal. Os factores de risco (FR) associados s��o sexo masculino, idade avan��ada, hipertens��o arterial, tabagismo e dislipidemias, cuja sinergia amplifica o risco cardiovascular global (RCG). Realizou-se um rastreio em indiv��duos da regi��o Norte de Portugal, com o objectivo de determinar o RCG, pela tabela derivada do projecto SCORE. Verificou-se excesso de peso e press��o arterial elevada em mais de metade da amostra. Observou-se que RCG passa a alto risco acima dos 50 anos. O RCG permite estimar a interac����o de FR individuais, permitindo definir estrat��gias interventivas, com potenciais ganhos em sa��de.

Impact of maritime air mass trajectories on the Western European coast urban aerosol

Lisbon is the largest urban area in the Western European coast. Due to this geographical position the Atlantic Ocean serves as an important source of particles and plays an important role in many atmospheric processes. The main objectives of this study were to (1) perform a chemical characterization of particulate matter (PM2.5) sampled in Lisbon, (2) identify the main sources of particles, (3) determine PM contribution to this urban area, and (4) assess the impact of maritime air mass trajectories on concentration and composition of respirable PM sampled in Lisbon. During 2007, PM2.5 was collected on a daily basis in the center of Lisbon with a Partisol sampler. The exposed Teflon filters were measured by gravimetry and cut into two parts: one for analysis by instrumental neutron activation analysis (INAA) and the other by ion chromatography (IC). Principal component analysis (PCA) and multilinear regression analysis (MLRA) were used to identify possible sources of PM2.5 and determine mass contribution. Five main groups of sources were identified: secondary aerosols, traffic, calcium, soil, and sea. Four-day backtracking trajectories ending in Lisbon at the starting sampling time were calculated using the HYSPLIT model. Results showed that maritime transport scenarios were frequent. These episodes were characterized by a significant decrease of anthropogenic aerosol concentrations and exerted a significant role on air quality in this urban area.