Evaluating Visual Photoplethysmography Method

Regular monitoring of common physiological signs, including heart rate, blood pressure, and oxygen saturation, can be an effective way to either prevent or detect many kinds of chronic conditions. In particular, cardiovascular diseases (CVDs) are a worldwide concern. According to the World Health Organization, 32% of all deaths worldwide are from CVDs. In addition, stress-related issues cost $190 billion in healthcare costs per year. Currently, contact devices are required to extract most of an individuals physiological information, which can be uncomfortable for users and can cause discomfort. However, in recent years, remote photoplethysmography (rPPG) technology is gaining growing interest, which enables contactless monitoring of the blood volume pulse signal using a regular camera, and ultimately can provide the same physiological information as a contact device. In this paper, we propose a benchmark comparison using a new multimodal database consisting of 56 subjects where each subject was submitted to three different tasks. Each subject wore a wearable device capable of extracting photoplethysmography signals and was filmed to allow simultaneous rPPG signal extraction. Several experiments were conducted, including a comparison between information from contact and remote signals and stress state recognition. Results have shown that in this dataset, rPPG signals were capable of dealing with motion artifacts better than contact PPG sensors and overall had better quality if compared to the signals from the contact sensor. Moreover, the statistical analysis of the variance method had shown that at least two HRV features, NNi 20 and SAMPEN were capable of differentiating between Stress and Non-Stress states. In addition, three features, IBI, NNi 20, and SAMPEN were capable of differentiating between tasks relating to different levels of difficulty. Furthermore, using machine learning to classify a stressed or unstressed state, the models were able to achieve an accuracy score of 83.11%.

Acoustic nondestructive testing and measurement of tension for steel reinforcing members

Many concrete structures contain internal post-tensioned steel structural members that are subject to fracturing and corrosion. The major problem with conventional tension measurement techniques is that they use indirect and non-quantitative methods to determine whether there has been a loss of tension. This work developed an acoustics-based technology and method for making quantitative tension measurements of an embedded, tensioned steel member. The theory and model were verified in the laboratory using a variety of steel rods as test specimens. Field tests of the method were conducted at three Corps of Engineers dams. Measurements of the longitudinal and shear velocity were done on rods up to 50 ft long. Not all rods of this length were able to be measured and the quality and consistency of the signal varied. There were fewer problems measuring the longitudinal velocity than shear velocity. While the tension predictions worked in the laboratory tests, the tension could not be accurately calculated for any of the field sites because researchers could not obtain the longitudinal or shear velocities in an unstressed state, or precise measurements of the longitudinal and shear velocities due to the unknown precise length of the rods in the tensioned state.

Peculiarities of girth body sizes in men with mild and severe psoriasis course

Given the most frequent manifestation of psoriasis at a young working age and in some cases severe, continuously recurrent course, the presence of many treatments, none of which is a guarantee of complete recovery and no recurrence – now there is an urgent need to find prognostic signs therapy and prevention of relapses. In the absence of ideal biomarkers, the study of constitutional markers becomes crucial. The aim of the study was to examine the differences in girth body sizes between healthy and/or psoriatic men depending on the severity of the disease. Anthropometric examination according to V.V. Bunak was performed for 32 men of the first mature age patients with mild and 68 with severe psoriasis course. The PASI index was used to clinically assess the severity and area of psoriatic lesions. The control group, according to anthropometric parameters, consisted of 82 practically healthy men of the same age, selected from the database of the research center of National Pirogov Memorial Medical University, Vinnytsya. Statistical data processing was performed in the license package “Statistica 5.5” using non-parametric methods of evaluation of the obtained results. In patients with psoriasis of mild and severe course, compared with healthy, we found: greater values for – the girth of the shoulder in a tense state by 8.9% and 6.8%; shoulder girth in the unstressed state by 14.2% and 12.3%; forearm girth in the upper part by 8.0% and 7.1%; forearm girth in the lower part by 4.2% and 4.5%; hand girth by 5.1% and 5.8%; hip girth by 11.4% and 9.3%; hips circumference by 8.7% and 6.5%; crus girth in the upper part by 10.2% and 7.9%; crus girth in the lower part by 8.7% and 5.9%; neck girth by 6.9% and 7.8%; waist circumference by 17.1% and 18.2%; chest girth on inspiration by 7.8% and 7.2%; chest girth on exhalation by 10.6% and 10.3%; chest circumference at rest by 10.0% and 9.6%. Thus, there are pronounced differences in the girth sizes between healthy and patients with mild and severe psoriasis Ukrainian men of the first mature age. Between patients with varying degrees of severity of dermatosis, differences are established only for the girth of the crus in the lower part.

Genetic Mutations That Drive Evolutionary Rescue to Lethal Temperature in Escherichia coli

Evolutionary rescue occurs when adaptation restores population growth against a lethal stressor. Here, we studied evolutionary rescue by conducting experiments with Escherichia coli at the lethal temperature of 43.0 °C, to determine the adaptive mutations that drive rescue and to investigate their effects on fitness and gene expression. From hundreds of populations, we observed that ∼9% were rescued by genetic adaptations. We sequenced 26 populations and identified 29 distinct mutations. Of these populations, 21 had a mutation in the hslVU or rpoBC operon, suggesting that mutations in either operon could drive rescue. We isolated seven strains of E. coli carrying a putative rescue mutation in either the hslVU or rpoBC operon to investigate the mutations’ effects. The single rescue mutations increased E. coli’s relative fitness by an average of 24% at 42.2 °C, but they decreased fitness by 3% at 37.0 °C, illustrating that antagonistic pleiotropy likely affected the establishment of rescue in our system. Gene expression analysis revealed only 40 genes were upregulated across all seven mutations, and these were enriched for functions in translational and flagellar production. As with previous experiments with high temperature adaptation, the rescue mutations tended to restore gene expression toward the unstressed state, but they also caused a higher proportion of novel gene expression patterns. Overall, we find that rescue is infrequent, that it is facilitated by a limited number of mutational targets, and that rescue mutations may have qualitatively different effects than mutations that arise from evolution to nonlethal stressors.

Role of Hydrogen in Cavitation Degradation of Iron in Water Solutions

Hydrogen ingress into a metal has been observed at cavitation in distilled water and in 3% NaCl solution at open circuit potential. The measurements of hydrogen permeation rate have been made using an ultrasonic cavitation facility with an attached Devanathan-Stachurski double cell. Increase in vibration amplitude has been associated with the increase in amplitude of electrochemical voltage and current pulses and with the modification of hydrogen permeation rate. Hydrogen behavior within the metal has been affected by the cavitation induced dynamic stresses and metal deformation hardening, ascertained on the basis of the appearance of hydrogen permeation transients at cavitation in comparison with those recorded for the unstressed state. Metal damage has been a resultof associated effects of cavitation and hydrogen.

Influential Parameter Study on the Main-Cable State of Self-Anchored Suspension Bridge

This paper made a thorough influencing parameter analysis on the unstressed state and completed state of main cable of self-anchored suspension bridge. The main cable curve, the amount and the action point of the resultant force of main cable on the main saddle were considered as the controlling objectives, the rational completed state of main cable was defined; Wusong bridge in Jilin city was taken as an example, the finite element mode of main cable was created. The unstressed state and the completed state of main cable under different parameters were calculated, and all the results were compared with the reference state, the influences of each parameter deviation on the state of main cable were studied: the self-weight and erection temperature of main cable had little effect on the state of main cable; the length of the mid-span main cable mainly influenced itself line-shape, while the length of the side-span main cable had significant effect on each controlling objective; made the unstressed line-shape of main cable as the controlling condition, the position deviation of the main saddle and back anchorage facet, happened before the main cable erection stage, had little effect on the completed state, but which will have great effect on the completed state when they happened after the main cable erection stage. Engineering example analysis results showed that, the tensile stiffness of main cable and the boom-completed force would have some effect on the completed state of main cable, and the tensile stiffness of main cable and the self-weight of the main beam should be tested before erecting the main cable, in the same time the deviation should be control within the rational limits; recommended that the unstressed shape of main cable should pre-lift, which could counteract the deformation of the main saddle and the back anchorage facet at the completed stage, this conclusion had a strong guiding significance and reference value on the work of constructing the main cable of self-anchored suspension bridge.

Implementing slack cables in the force density method

Purpose – The purpose of this paper is to present a solution strategy for the analysis of cable networks which includes an extension to the force density method (FDM) in an attempt to support cable elements when they become slack. The ability to handle slack cable elements in the analysis is particularly important especially in cases where the original cable lengths are predefined, i.e. the cable structure has already been constructed, and there is a need for further analysis to account for additional loading such as wind. The solution strategy is implemented in a software application. Design/methodology/approach – The development of the software required the implementation of the FDM for the analysis of cable networks and its extension to handle constraints. The implemented constraints included the ability to preserve the length in the stressed or the unstressed state of predefined cable elements. In addition, cable statics are incorporated with the development of the cable equation and its modification to be able to be handled by the FDM . Findings – The implementation of the solution strategy is presented through examples using the software which has been developed for these purposes. Originality/value – The results suggest that for cable networks spanning large distances or cable elements with considerable self-weight the neglect of the cable slackening effects is not always conservative.

Modeling Unstressed State of Kinematic Indeterminate Systems

Kinematic indeterminate systems under construction state and even in-service state may undergo marked displacement. The mathematical model is developed for determination of displacement in kinematic indeterminate systems. The proposed procedures are extended to describe unloading process from prestressed to unstressed state, with particular emphasis on the applications of the unstressed state analysis of practical interest.