Background Some methodologies used for evaluating sweat production and antiperspirants are of a stationary aspect, that is, most often performed under warm (38°C) but resting conditions in a rather short period of time. The aim is to develop an electronic sensor apt at continuously recording sweat excretion, in vivo, during physical exercises, exposure to differently heated environments, or any other stimuli that may provoke sweat excretion. Material and Methods A sensor (20 cm2) is wrapped under a double‐layered textile pad. Fixed onto the armpits, these two arrays of electrodes are connected to electronic system through an analog multiplexer. A microcontroller is used to permanently record changes in the conductance between two electrodes during exposure of subjects to different sweat‐inducing conditions or to assess the efficacy of applied aluminum hydrochloride (ACH)‐based roll‐ons at two concentrations (5% and 15%). Results In vitro calibration, using a NaCl 0.5% solution, allows changes in mV to be related with progressively increased volumes. In vivo, results show that casual physical exercise leads to sweat excretions much higher than in warm environment (37 or 45°C). Only, an exposure to a 50°C environment induced comparable sweat excretion. In this condition, sweat excretions were found similar in both armpits and both genders. Decreased sweat excretions were recorded following applications of ACH, with a dose effect. Conclusion Developing phases of this new approach indicate that usual method or guidelines used to determine sweat excretions in vivo do not reflect true energy expenditure processes. As a consequence, they probably over‐estimate the efficacy of antiperspirant agents or formulae.
Capacitive transducer/adsorption element based hardware-and-software diagnostics system that implements human perspiration measurement and monitoring under normal and pathological conditions (primary hyperhidrosis) was designed.
The weight reduction of numerous consumer electronic devices is of increasing importance. In this respect, ultra-light magnesium alloys have attracted more attention to be used as frame materials. Nevertheless, Mg alloys are of intrinsically poor corrosion resistance, especially in chloride ion-containing environments. Human perspiration fluid with a relatively high chloride ions content (~ 0.14 M) comes in contact with a number of consumer products resulting in a variety of undesirable effects such as malfunction and corrosion. Based on that, the present work addresses the corrosion behavior of five AZ-Mg alloys including AZ91D, AZ80E, AZ31, AM60 and AXJ530 in artificial perspiration biofluid at human body temperature of 37 °C. The study is performed using electrochemical impedance spectroscopy and potentiodynamic polarization techniques supported by surface morphological and EDX spectra examinations. The surface layer total resistance value (R T) estimated from the analysis of obtained impedance data after 12-h exposure period reveals that durability of our tested samples increases in the following sequence: AZ80 > AZ91 > AZ31 > AM60 > AXJ530 > Mg (control). AZ80E alloy at top of this sequence points to its significantly high anti-corrosion performance in artificial perspiration biofluid and thus can be the best Mg materials of choice for many housing consumer electronic products. This outcome is in consistence with the corrosion rate (P i in mm y−1) trend as derived from the potentiodynamic polarization data that decreases in the following order: AZ80 (0.25) < AZ91 (0.49) < AZ31 (1.03) < AM60 (1.23) < AXJ530 (5.36) < Mg (5.98). Both FE-SEM images and EDX analyses further confirm these experimentally electrochemical findings.
In this study, a bench-scale system was utilized to assess the disinfection byproduct (DBP) formation from human endogenous organic matter. Perspiration and urine, constituting the main organic substances in swimming pools, were selected to represent the major human endogenous organics. Results revealed that the continuous input of body fluids into the reactor led to rapid accumulation of endogenous organic matter, which contributed to high concentrations of DBPs in the swimming pool. The increase in nonpurgeable organic carbon (NPDOC) concentration from the perspiration precursor was lower than that from urine during the operation. Moreover, the accumulation of swimmers' body fluids leads to increased DBP precursors, as well as increased chlorine demand and DBP formation in swimming pool water. The concentration of the trihalomethanes (THMs) and haloacetic acids (HAAs) consistently increased during the reaction. More THMs were generated in urine solution, whereas more HAAs were found in perspiration solution. To improve the water quality in swimming pools, ozonation, UV/Chlorine, and UV/H2O2 treatments were evaluated for their efficacy in reducing the DBP precursors. Results revealed that all of the three treatment processes can degrade the DBP precursors in perspiration and urine, eventually decreasing the DBP concentrations. However, only the UV/H2O2 treatment can decrease the formation of DBPs in perspiration and urine. In addition, the results revealed that UV/Chlorine and UV/H2O2 treatments should be operated for a sufficient contact time to prevent the increased production of DBP precursors in water at the early stage of the treatment. [Display omitted] •DBP formation from endogenous organic matter in swimming pool was assessed.•Continuous input of perspiration and urine led to accumulation of organic matter.•Ozonation, UV/Chlorine, and UV/H2O2 can degrade the DBP precursors in water.•UV/H2O2 can decrease the DBP formation from perspiration and urine.•A longer contact time is needed for UV/Chlorine and UV/H2O2 to reduce DBP precursors.
Functional laser scribing carbon paper (LSCP) decorated with highly uniform Ni nanoparticles were constructed through a facile electroless plating. The nanocomposites were characterized by high resolution scanning electron microscope, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, cyclic voltammetry and chronoamperometry. The results showed high electron transferring kinetics of this sensor, which can be ascribed to their excellent properties such as rich pore channels, excellent structural durability, and large surface area. These properties facilitated mass transfer and electron conductions. Notably, a systematical response surface methodology simulating-modeling-predicting-optimizing design was employed to simulate, model and optimize processing parameters to gain the optimal conductivity of 8.52 × 106 S m−1. The obtained sensor owned high electrochemical activity and wide linear responses (0.80 μM–2.50 mM and 4.50 mM–15.20 mM), low detection limit of 20 nM (S/N = 3) to the glucose detection. The glucose determination in human serum and perspiration samples are also successful. Therefore, LSCP/NN provides an excellent sensing platform towards flexible biosensors in monitoring physical conditions. Disposable, Non-enzymatic and Ultrasensitive Carbon Fiber Paper-based Glucose Sensor has been Constructed by A Theoretical Box-Behnken Modeling-Predicting-Optimizing Design. [Display omitted] •A disposable, ultrasensitive and highly flexible LSCP/NN glucose biosensor is firstly constructed.•Novel nanoporous Ni networks are integrated with pulsed laser-scribed carbon paper via a rational Box-Behnken modeling-predicting-optimizing design.•The enzyme-free and binder-free LSCP/NN biosensor exhibits a wide linear glucose determination range (0.80 μM–2.50 mM; 4.5 mM–15.2 mM).•Excellent sensitivity (3415 μA mM−1 cm−2), a fast response (<1 s) and ultra-low limit of detection (20 nM).•Favorable flexibility, good accuracy and satisfactory specificity for glucose quantification in human serum and perspiration are indicated by the LSCP/NN biosensor.
Apparent evaporative cooling efficiency has typically been determined by applying a pre-wetted fabric “skin” on a dummy (“manikin”) simulating human thermal physiology, to understand the effective cooling components of body perspiration in clothing systems. This procedure is only a very rough approximation of real life, as the pre-wetted fabric does not have the capacity to continuously push extra moisture into the clothing layers, which would happen with continuous sweating of the body. In this study, a sweating torso was used to mimic different sweating situations (100, 175 and 250 g/h) with twelve single-layer (SI) and multilayer (MU) clothing systems to understand the effect of continuous sweating and its interaction with clothing materials on cooling efficiency. Our experiments revealed that evaporative cooling efficiency is affected differently by continuous sweating when compared to pre-wetted fabric “skin” approaches. With continuous sweating, up to 15% (24 W m−2) cooling power came from the so-called “heat pipe effect” and/or wet conduction and 24% (44 W m−2) evaporative latent heat was gained from the environment. It was found that the increase of perspired moisture can affect evaporative cooling efficiency for hydrophilic materials in dual ways. For each 75 g/h sweat rate increase, the in-plane moisture transfer can raise the evaporative cooling efficiency of SIs at least 3–12% and the transplanar moisture transfer may reduce the evaporative cooling efficiency by at least 2–7% and 2–9% for SIs and MUs, respectively. For hydrophobic materials, the evaporative cooling efficiency was less affected by different levels of perspiration due to low wicking. Results also showed the negative correlation of evaporative cooling efficiency of hydrophilic materials with fabric evaporative resistance and thickness. Our study contributes to the understanding of the effective sweat cooling power and evaporative latent heat from environment for the clothed human body with continuous sweating. It also provides insight into the interaction between liquid and water vapor transport, and material design for optimizing the evaporative cooling. •Quantification of sweating cooling power in clothing with continuous liquid sweating.•Quantification of heat pipe effect on total heat loss.•Effect of sweat rate and materials properties (hydrophilicity) on apparent evaporative cooling.
Display omitted] •An ultrasensitive and highly flexible glucose biosensor is constructed.•Porous copper networks are integrated with a laser-scribed carbon paper substrate.•A wide linear glucose determination range from 1.0 μM to 7.96 mM.•An ultrahigh sensitivity, a fast response and ultra-low limit of detection.•Excellent flexibility, good accuracy and satisfactory specificity. Owing to the high specific surface area and easy accessability to targeting biomolecules, emerging non-noble-metal networks are developed as an ultra-active catalyst for molecular detection. In this work, a facile flexible enzyme-free glucose sensor with superior sensing performance has been successfully constructed by integrating laser-scribed carbon paper (LSCP) with copper network (CN). Remarkably, operation parameters are modeled and optimized by Central Composite Design (CCD) to obtain an optimal conductivity of 4.783 × 107 S·m−1 for CN. Due to the great electronic/ionic pathway between LSCP of ample active sites and CN of excellent conductivity, the disposable biosensor exhibits fast electron transfer kinetics. For glucose detection, LSCP/CN exhibits an excellent sensitivity of 3626.6 μA mM−1 cm−2, a wide linear range from 1 μM to 7.96 mM, an ultra-low detection limit of 30 nM (S/N = 3) as well as favorable reusability. Satisfactory anti-interference capacity to electro-active oxides and selectivity against carbohydrates studied for concentrations up to normal physiologic levels and higher concentrations are systematically investigated. The applications of glucose determination in human serum and perspiration samples are also successful, with recoveries of 100.8% (± 2.28%) and 92.1% (±3.61%), respectively. Experimentally, the current response of the LSCP/CN biosensor is resilient to mechanical deformation with less than 8% decay even after 1000 cycles of 1 mm repeated bending and 180° cyclical folding tests. As such, LSCP/CN can be applicable for flexible, attachable and potentially wearable biosensors to attain real-time physiological monitoring.
Primary hyperhidrosis (PH) is a common pathological condition related to excessive sweating. It may be associated with depression. Therefore, the main aim of this study was to analyse and compare depression scores between subjects without PH (degree‐I) and patients with PH (degrees‐II, ‐III, and ‐IV). The secondary aim was to describe and compare depression scores among subjects with different PH degrees (I—without perceptible perspiration, II—tolerable perspiration, III—hardly tolerable perspiration, and IV—intolerable perspiration). A sample of 100 subjects with a median age of 23.00 ± 6.00 years was recruited from an outpatient medical centre, where medical history data were registered. The degree of PH was determined using the Hyperhidrosis Disease Severity Scale from degrees I (mild) to IV (very severe). The depression scores were analysed using the Beck Depression Inventory (BDI). Statistically significant differences (P < 0.001) were observed for higher BDI scores in the patients with PH (degrees II, III, and IV) than in those without PH (degree‐I). Kruskal‐Wallis tests demonstrated statistically significant differences for BDI scores (P < 0.001), with higher values for degree‐III with respect to degree‐I and degree‐IV with respect to degree‐I. Patients with a greater degree (especially III/IV) of PH showed higher BDI scores compared with subjects without PH.
Display omitted] All life forms use a seamless integration of physical and chemical sensing mechanisms to enhance their performance and survival skills. To mimic the integrative sensing abilities found in nature, there is a significant interest in developing wearable devices that can smartly track the physiological and biochemical signals of the human body. Progress in wearable physical sensors has been remarkable giving rise to a number of consumer electronics products meant to measure parameters related to activity, posture, heart rate, respiration rate, and blood oxygen level. Comparatively, the progress in wearable chemical sensor development has been slower because of the inherent challenges in retrieving and processing bodily fluids. In this context, sweat provides a rich repository of biomarkers that is accessible continuously, on-the-go, and non-invasively. Here we provide a review of recent trends in the area of wearable sweat sensing with discussions on relevant topics of interest in material science, device development, sensing mechanisms, power generation, and data management. Exemplary wearable sweat sensors published in recent years are provided along with commercialization efforts in wearable sweat sensing. The review highlights the trends in multifunctional sensing platforms with flexible electronics that integrate data from both physical and biochemical sweat sensors.
The effect of the pre-bond contamination with fingerprint (FP), both during the production and the application of adhesively bonded patch repairs on composite aircraft parts, and the cumulative effect of fingerprint and hygrothermal ageing on the fracture toughness of carbon fiber reinforced plastic (CFRP) bonded joints are experimentally investigated. To this end, mode I and mode II fracture toughness tests were conducted on FP contaminated coupons and mode II fracture toughness tests on FP contaminated and aged coupons. The artificial FP was supposed to mimic the accidentally applied fingerprints on the CFRP adherent and was applied on the adherent in the size of a human thumb. The two investigated FP formulations consisted of an artificial hand perspiration solution for the production scenario, and of Skydrol hydraulic-oil for the repair scenario. Three levels of contamination with FP were considered for each scenario. The hygrothermal ageing conditions applied until moisture saturation achieved were 70 °C/85% RH. Prior to bonding, the CFRP adherent surfaces were inspected using full-scale monitoring with optically stimulated electron emission (OSEE), an extended nondestructive testing method, in order to analyze the physicochemical variations at the contaminated surface of the adherents before bonding. The ANOVA statistical method was used to assist the evaluation of the results and the deduction or reliable conclusions. The results revealed that the pre-bond FP contamination of the adherents leads to the reduction of the fracture toughness of the CFRP bonded joints. After-bond hygrothermal ageing under the prescribed conditions had no significant influence on the moisture absorption and load carrying capacity of the joint. However, it influenced the bondline integrity as it led to a significant reduction of the fracture toughness of the joint. The effect of the combination of pre-bond contamination and after-bond hygrothermal ageing is more severe than the two separate effects.