Controlling ligand surface density on streptavidin-magnetic particles by a simple, rapid, and reliable chemiluminescent test

International audienc

The proportional partitional Shapley value

A new coalitional value is proposed under the hypothesis of isolated unions. The main difference between this value and the Aumann–Drèze value is that the allocations within each union are not given by the Shapley value of the restricted game but proportionally to the Shapley value of the original game. Axiomatic characterizations of the new value, examples illustrating its application and a comparative discussion are provided.Peer ReviewedPostprint (author’s final draft

Voltammetric determination of size and particle concentration of Cd-based quantum dots

In this article, we present two novel methodologies, using a simple electrochemical approach, for the determination of the size and particle concentration of Cd-based Quantum Dots (QDs), nanoparticles widely used as photoluminescent labels in many bioanalytical applications. Such QDs were analyzed directly in organic medium and in water after derivatization with an amphiphilic polymer. Screenprinted carbon electrodes modified with a bismuth film were employed as the electrochemical platform. The herein proposed methodologies allow the reliable determination of very low nanoparticle concentrations. Detection limits achieved with the selected experimental conditions were of 3.0 1012 nanoparticles mL1 for CdSe QDs dispersed in organic medium and of 6.0 1012 nanoparticles mL1 for water-solubilized CdSe/ZnS QDs (both with a core size of 3.26 nm). However, detection limits could be improved increasing the QDs sample volume or the voltammetric deposition time. Furthermore, the proposed methodologies allowed the determination of the CdSe QDs diameters. Results obtained were validated after comparison with standard spectroscopic approaches. The electrochemical characterization of QDs, disclosed in this work, allows to perform a synthesis control with a simple, inexpensive and fast approach

PREVALÊNCIA DE FATORES DE RISCO CORONARIANO EM PRATICANTES de atividades aeróbiCas NO CAMPUS DA UNIVERSIDADE FEDERAL DE VIÇOSA – MG

O objetivo deste estudo foi determinar a prevalncia de fatores de risco coronariano em praticantes de atividades aerbicas no campus da Universidade Federal de Viosa (UFV). Utilizou-se de uma ao descritiva transversal, sendo avaliados 50 homens na faixa etria de 30 a 50 anos, por meio do questionrio de risco coronariano da Michigan Heart Association (MCARDLE; KATCH; KATCH, 2001). A estatstica empregada constituiu-se da anlise descritiva, do clculo do percentual da ocorrncia do risco coronariano e do clculo da taxa de prevalncia de cada fator de risco. O risco coronariano mdio obtido foi de 22,56 3,70 (15 a 31) pontos, classificado como risco mdio. Os resultados apontaram que 6% (n=3) da amostra foi classificada como risco abaixo da mdia; 58% (n=29), como risco mdio; e 36% (n=18), como risco moderado. O fator de risco com maior prevalncia esteve relacionado hereditariedade (62%, n=31), seguido de sobrepeso (62%, n=31) e hipercolesterolemia (46%, n=23). Conclui-se que a prevalncia de fatores de risco coronariano em praticantes de atividades aerbicas no campus da UFV mostrou ser de risco mdio. O sobrepeso foi o fator de risco modificvel com maior possibilidade de interveno, visando reduzir o nvel de risco observado

Measuring skin temperature before, during and after exercise: a comparison of thermocouples and infrared thermography

Measuring skin temperature (TSK) provides important information about the complex thermal control system and could be interesting when carrying out studies about thermoregulation. The most common method to record TSK involves thermocouples at specific locations; however, the use of infrared thermal imaging (IRT) has increased. The two methods use different physical processes to measure TSK, and each has advantages and disadvantages. Therefore, the objective of this study was to compare the mean skin temperature (MTSK) measurements using thermocouples and IRT in three different situations: pre-exercise, exercise and post-exercise. Analysis of the residual scores in Bland-Altman plots showed poor agreement between the MTSK obtained using thermocouples and those using IRT. The averaged error was -0.75 °C during pre-exercise, 1.22 °C during exercise and -1.16 °C during post-exercise, and the reliability between the methods was low in the pre- (ICC = 0.75 [0.12 to 0.93]), during (ICC = 0.49 [-0.80 to 0.85]) and post-exercise (ICC = 0.35 [-1.22 to 0.81] conditions. Thus, there is poor correlation between the values of MTSK measured by thermocouples and IRT pre-exercise, exercise and post-exercise, and low reliability between the two forms of measurement

Sources of experimental errors in the observation of nanoscale magnetism

It has been recently reported that some non-magnetic materials in bulk state, exhibit magnetic behavior at the nanscale due to surface and size effects. The experimental observation of these effects is based on the measurement of very small magnetic signals. Thus, some spurious effects that are not critical for bulk materials with large magnetic signals may become important when measuring small signals (typically below 0.0001 emu). Here, we summarize some sources of these small magnetic signals that should be considered when studying this new nanomagnetismComment: 16 pages, 10 figure

Time required to stabilize thermographic images at rest

Thermography for scientific research and practical purposes requires a series of procedures to obtain images that should be standardized; one of the most important is the time required for acclimatization in the controlled environment. Thus, the objective of this study was to identify the appropriate acclimatization time in rest to reach a thermal balance on young people skin. Forty-four subjects participated in the study, 18 men (22.3 ± 3.1 years) and 26 women (21.7 ± 2.5 years). Thermographic images were collected using a thermal imager (Fluke ®), totaling 44 images over a period of 20 minutes. The skin temperature (TSK) was measured at the point of examination which included the 0 minute, 2, 4, 6, 8, 10, 12, 14, 16, 18 and 20. The body regions of interest (ROI) analyzed included the hands, forearms, arms, thighs, legs, chest and abdomen. We used the Friedman test with post hoc Dunn?s in order to establish the time at rest required to obtain a TSK balance and the Mann-Whitney test was used to compare age, BMI, body fat percentage and temperature variations between men and women, considering always a significance level of pmenor que0.05. Results showed that women had significantly higher temperature variations than men (pmenor que0.01) along the time. In men, only the body region of the abdomen obtained a significant variance (pmenor que0.05) on the analyzed period, both in the anterior and posterior part. In women, the anterior abdomen and thighs, and the posterior part of the hands, forearms and abdomen showed significant differences (pmenor que0.05). Based on our results, it can be concluded that the time in rest condition required reaching a TSK balance in young men and women is variable, but for whole body analysis it is recommended at least 10 minutes for both sexes