Correlation between skin temperature and heart rate during exercise and recovery,and the influence of body position in these variables in untrained women

It was known that the thermal response varies according to some variables. Until now, there are no studies that have investigated the relationship of skin temperature and heart rate during and after the workout, either the thermal behavior during postural changes. Objective: the aim of this study was to evaluate the behavior of skin temperature and heart rate, during exercise and up to an hour of recovery (with postural change), performed in two different intensities sessions (70% and 85% of 10 repetitions maximum) and observe the correlation between them. Method: This was a short longitudinal study, carried out with women aged from 18 to 30 years. A sample of 31 untrained women, aged 18 and 30 was used. The volunteers were randomized into two groups: Biceps Group (BG), with 15 women, and Quadriceps Group (QG) with 16 women. Results: During and after completion of the exercise session, there was a significant reduction in skin temperature on the active muscles in both groups (BG and QG), with similar thermal responses for the two intensities studied (70% and 85%) to the minute 15 (which marks the end of the recovery in the standing position). From minute 15 to minute 20–60, the skin temperature increases abruptly and significantly, returning to levels close to those observed before exercise. Conclusion: There were no statistical differences in thermal response to exercises in 70% or 85% of 10RM. There is a negative correlation between heart rate and skin temperature when untrained women perform anaerobic exercise. It was observed that after a change of posture (from a standing position to a sitting posture) skin temperature increased abruptly and significantly.     

Treatment of uncorrected measurement bias in uncertainty estimation for chemical measurements

Consistent treatment of measurement bias, including the question of whether or not to correct for bias, is essential for the comparability of measurement results. The case for correcting for bias is discussed, and it is shown that instances in which bias is known or suspected, but in which a specific correction cannot be justified, are comparatively common. The ISO Guide to the Expression of Uncertainty in Measurement does not provide well for this situation. It is concluded that there is a need for guidance on handling cases of uncorrected bias. Several different published approaches to the treatment of uncorrected bias and its uncertainty are critically reviewed with regard to coverage probability and simplicity of execution. On the basis of current studies, and taking into account testing laboratory needs for a simple and consistent approach with a symmetric uncertainty interval, we conclude that for most cases with large degrees of freedom, linear addition of a bias term adjusted for exact coverage ("U(e)") as described by Synek is to be preferred. This approach does, however, become more complex if degrees of freedom are low. For modest bias and low degrees of freedom, summation of bias, bias uncertainty and observed value uncertainty in quadrature ("RSSu") provides a similar interval and is simpler to adapt to reduced degrees of freedom, at the cost of a more restricted range of application if accurate coverage is desired.     

Supported liquid membranes (SLM) for recovery of bismuth from aqueous solutions

In this study, the extraction of Bi(III) from synthetic solutions of 2 M H₂SO₄/0.5 M HCl by supported liquid membranes (SLM) using tri-n-octylphosphine oxide (Cyanex 921) as extractant is reported. First, the nature of the Bi(III)/Cyanex 921 solvates extracted to organic phase (in a solvent extraction system) was determined by the slope method. It was found that Bi(III) reacts with 2 molecules of Cyanex 921 to form the solvate BiCl₃·2Cyanex 921. In the recovery of Bi(III) by the SLM system, parameters that influence extraction efficiency were evaluated, including: support, feed solution and stripping solution nature, and extractant concentration in the organic phase which impregnates the support. Results indicate that Cyanex 921 dissolved in kerosene is not able to extract Bi(III) from H₂SO₄ media. Moreover, transfer of H₂SO₄ was observed. HCl addition to the feed solution up to a maximum concentration of 0.5 M increases Bi(III) extraction. Further increase in HCl concentration causes a decrease in Bi(III) transfer. Likewise, the concentration of Cyanex 921 in the SLM organic phase which produced the maximum Bi(III) extraction was found to be 0.3 M. The performance of H₂O and 0.2 M H₂SO₄ as stripping solutions was evaluated, and it was found that only H₂SO₄ enabled Bi(III) transfer.     

Investigation of microstructure evolution during self-annealing in thin Cu films by combining mesoscale level set and ab initio modeling

Microstructure evolution in thin Cu films during room temperature self-annealing is investigated by means of a mesoscale level set model. The model is formulated such that the relative, or collective, influence of anisotropic grain boundary energy, mobility and heterogeneously distributed stored energy can be investigated. Density functional theory (DFT) calculations are performed in the present work to provide the variation of grain boundary energy for different grain boundary configurations. The stability of the predominant (111) fiber texture in the as-deposited state is studied as well as the stability of some special low-Σ grain boundaries. Further, the numerical model allows tracing of the grain size distribution and occurrence of abnormal grain growth during self-annealing. It is found that abnormal grain growth depends mainly on the presence of stored energy variations, whereas anisotropic grain boundary energy or mobility is insufficient to trigger any abnormal growth in the model. However, texture dependent grain boundary properties, mobility in particular, contribute to an increased content of low-Σ boundaries in the annealed microstructure. The increased presence of such boundaries is also promoted by stored energy variations. In addition, if the stored energy variations are sufficient the coexisting (111) and (001) texture components in the as-deposited state will evolve into a (001) dominated texture during annealing. Further, it is found that whereas stored energy variations promote the stability of the (001) texture component, anisotropic grain boundary energy and mobility tend to work the other way and stabilize the (111) component at the expense of (001) grains.     

Recovery of polyols from flexible polyurethane foam by “split-phase” glycolysis: Study on the influence of reaction parameters

The general purpose of polyurethane chemical recycling is to recover constituent polyol, a valuable raw material. Among suitable processes, glycolysis, especially in two phases, allows better quality products. Potassium octoate a compound derived from cycloaliphatic carboxylic acids shows suitable catalytic activity.A detailed study of the main reaction parameters affecting the reaction and properties of the recovered polyol has been carried out. They include carboxylate catalyst concentration, reaction temperature and mass ratio of treated foam to the glycolysis agent.An increase in the reaction temperature and catalyst concentration enhances the degradation rate, however, it also affects the process negatively by promotion of secondary reactions and contamination of the polyol phase. Related to the glycolysis agent amount, the minimum quantity required to split the phases has been determined, as well as the optimal ratio.     

Determination of Polycyclic Aromatic Hydrocarbons in Mangrove Sediments: Comparison of Two Internal Standard Surrogate Methods and Quality-Control Procedures

Two internal standard surrogate (ISS) methods, ISS-I (with m-terphenyl as a single ISS) and ISS-2 (using five deuterated PAHs as a multi-ISS), for the determination of polycyclic aromatic hydrocarbons (PAHs) in mangrove sediments were compared. The recovery percentages of 16 PAHs except naphthalene in HS-6 (a certified reference material) were high, ranging from 69.3 to 111.8% for ISS-1 and from 71.8 to 120.3% for the ISS-2 method. Similarly, the PAH recovery percentages in spiked mangrove sediments and clean sand were lower for ISS-I than for ISS-2, but both methods met the accurate acceptance criteria for PAH recoveries. The reproducibility (i.e. the method precision) between the two ISS methods was also comparable and satisfactory, with relative standard deviation values in most cases within 20% of the data variability. These results indicate that both ISS methods were acceptable for the determination of PAHs in mangrove sediments, despite the fact that the matrix of mangrove sediments may interfere with the PAH recovery efficiency.     

The radiation induced color centers of the LaBr3:Ce crystal

This paper presents study of the gamma-rays induced radiation damage in the LaBr₃:Ce crystal. The light output and transmittance are measured before and after γ-rays irradiations with an integrated dose up to 10⁶ rad for two LaBr₃:Ce samples. After γ-rays irradiation, LaBr₃:Ce crystal shows very slow recovery process or has no recover under room temperature, indicating that the radiation damage in LaBr₃:Ce crystal is not dose date dependent. Meanwhile, it's found that the radiation induced color centers are respectively peaked at the wavelength of 448 nm, 512 nm and 590 nm. Those color centers should be ascribed to the V_k, V_F and F center respectively.     

Incorporating human fatigue and recovery into the learning–forgetting process

The available learning and forgetting models do not consider the physical loading that performing a task requires. In some situations, physical loading results in workers’ fatigue on the job that is followed by rest breaks to alleviate it. The aim of this paper is to present the “learning–forgetting–fatigue–recovery model” (LFFRM) that addresses possible issues relating to workers’ capabilities and restrictions in manufacturing environments. Numerical examples are solved to address some research questions regarding the model optimization and its constraints. The main results show that incorporating learning into a production process decreases fatigue and improves the performance of the system. Worker fatigue, on the other hand, increases production time and decreases production output. A recovery break must be of enough length to alleviate some of the accumulated fatigue. However, longer recovery times extend the lead time and deteriorate the production performance due to forgetting.     

Establishment of signal-recovery functions for calculation of recovery factor. Application to monitoring of contaminant residues in vegetables by chemiluminescence detection

A new strategy is proposed for verifying if recovery factor is constant and independent of the real analyte content of samples. A signal-recovery function has been developed on the basis of measurement of spiked test samples before and after a pre-treatment step and considering, as starting point, a recent IUPAC recommendation which distinguishes between two terms—recovery factor, R, and apparent recovery, R*. Apparent recovery includes recovery factor and a new recovery term proposed in a previous paper by the authors, named calibration recovery, R ^C. The signal-recovery function is obtained directly from the measured analytical signals instead of from the concentrations, simplifying the calculations. A linear signal-recovery curve indicates that the recovery factor is constant in the analyte concentration range studied experimentally and, in this way, a single recovery factor can be calculated. The usefulness of the proposed method has been shown by quantification of the pesticide carbaryl by two different flow-injection analysis methods with chemiluminescent detection based on the luminol and TCPO systems. Good results were obtained from both methods.     

The effects of sampling materials selection in the collection of reduced sulfur compounds in air

In this study, the analytical bias in the measurements of reduced sulfur compounds (RSC) was investigated in terms of sorptive loss caused by the materials selected for the sample introduction. For the purpose of this study, three vacuum samplers made in the combination of different vacuuming efficiencies (e.g., rapid versus slow sampling) and different materials (i.e., Teflon versus stainless steel (SS)) were tested to evaluate the sampling recovery rate (RR) for five RSCs: H₂S, CH₃SH, DMS, CS₂ and DMDS. To make a parallel comparison of RR, the RSC standard samples contained in one bag were transferred to another bag using each sampling system. Their relative contents between, before, and after the transfer were then evaluated between different samplers to assess the sampling bias caused by the interaction between RSC and the sampling material. In the case of the most reactive compound, H₂S, the sampling loss from the SS inlet line amounted to as high as 45%, while that for the Teflon counterpart was almost insignificant. When the sampling time was arbitrarily elongated (i.e., use of a slow sampler), the sampling loss rate of the SS inlet sampler became more significant with the RR values dropping down from 55 to 70%, across different RSCs. The overall results of our comparative study indicate that the sampling system for the reactive gaseous compounds should be checked for the material feasibility to guarantee sufficient analytical reliability.