RH Environment Research Articles

Pre-, Per- and post-cooling strategies used by competitive tennis players in hot dry and hot humid conditions.

This research investigated the pre-, per- and post cooling strategies used by competitive tennis players from various levels of play who occasionally train and compete in hot (>28°C) and humid (>60% rH), and dry (<60% rH) environments. 129 male tennis players (Mage = 24.9) competing at regional (N = 54), national (N = 30) and international (N = 45) levels, completed an online questionnaire regarding their use (i.e., timing, type, justification and effectiveness) of pre- (i.e., before practice), per- (i.e., during exercise) and post-cooling strategies when playing tennis in hot dry (HD) and hot humid (HH) conditions. Individual follow-up interviews were also carried on 3 participants to gain an in-depth understanding of the player's experience. Competitive tennis players used both internal and external cooling strategies to combat the negative effects of HD and HH conditions, but considered the HH to be more stressful than HD and experienced more heat-related illness in HH environments. International players used cold packs and cold towel more frequently than the regional and national players in hot environments, and used cold water immersion and cold vest more frequently than the latter in HH. Differences in strategy use were mostly observed during per-cooling where regional and national players more frequently used cold drinks than international players who more frequently used cold packs in HD and cold towel in HH conditions. Moreover the latter more frequently used cold towel, cold packs and cold water immersion as post-cooling strategies than regional players. When playing tennis in the heat, it is strongly recommended to employ cooling strategies to maintain health, limit declines in performance, and promote recovery. We also recommend improving education regarding the appropriate use and effectiveness of cooling strategies, and increasing their availability in tournaments.

Age-Related Differences in the Onset of Cardiovascular Drift during Progressive Heat Stress (PSU HEAT Project)

As a result of the increasing duration, frequency, and severity of heat waves, older men and women are at greater risk for heat-related morbidity and mortality, with the majority of excess heat-related deaths attributed to increased cardiovascular strain associated with heat stress. PURPOSE: To (1) identify the environmental conditions (ambient temperature (Tdb) and humidity (rh)) at which heart rate (HR) begins to increase from equilibrium (i.e., the onset of cardiovascular drift), and (2) compare the environments in which cardiovascular drift begins relative to those at which a continuous rise in core temperature (Tc) is observed in young (Y), middle (MA), and older (O) adults. Methods: 26 Y (10 F; 19-29 yrs), 27 MA (21F; 40-64 yrs), and 19 O (7 F; 65-76 yrs) subjects were exposed to progressive heat stress in an environmental chamber at a low metabolic rate reflecting activities of daily living (159 ± 34 W) in a warm-humid (WH, 34-36°C, 50-80% rh) and a hot-dry (HD, 38°C-52°C, &lt;30% rh) environment. The environmental thresholds above which HR and Tc equilibrium could no longer be maintained were identified. Results: In WH environments, sustained increases in HR preceded the Tc inflection point in Y (73±5% rh vs. 81±5% rh; p&lt;0.001), MA (67±11% rh vs. 73±12% rh; p&lt;0.001), and O adults (53±11% rh vs. 57±12% rh; p=0.041). Similarly, in HD (15-20% rh) environments, the onset of cardiovascular drift preceded the Tc inflection point in Y (47±3°C vs. 49±3°C; p=0.004), MA (44±4°C vs. 46±4°C; p&lt;0.001), and O adults (42±5°C vs. 44±4°C; p=0.007). Additionally, in WH environments, cardiovascular drift began at lower combinations of Tdb and rh in O vs. Y subjects (34°C, 53±11% rh vs. 34°C, 73±5% rh; p&lt;0.001) and O vs. MA adults (34°C, 53±11% rh vs. 34°C, 67±11% rh; p=0.008). In HD environments, cardiovascular drift began at lower environments in MA vs. Y (44±4°C, 18% rh vs. 47±3°C, 15% rh; p=0.044) and O vs. Y (42±5°C, 20% rh vs. 47±3°C, 15% rh; p=0.006) CONCLUSION: These data suggest that cardiovascular drift, indicating increases in cardiovascular strain, occurs during compensable heat stress at metabolic rates reflecting activities of daily living in Y, MA, and O adults. Further, there is an age-associated shift in the onset of cardiovascular drift toward lower combinations of Tdb and rh. SIGNIFICANCE/NOVELTY: These results are the first to identify the specific environmental conditions at which increases in cardiovascular strain occur across the adult age spectrum. These findings provide concrete data for the development of safety guidelines and policy decisions to mitigate cardiovascular-related morbidity and mortality during impending heat events. Supported by NIA Grant T32 AG049676 (to R.M.C.) and NIH Grant R01 AG067471 (to W.L.K.). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Impact of temperature on physical and cognitive performance in elite female football players during intermittent exercise.

There is limited research on female football players, especially related to their physical and cognitive performance under different climactic conditions. We analyzed the impact of a hot environmental temperature on physical performance and anticipation in elite female football players during a fatigue-inducing intermittent protocol. Elite female players (n = 21) performed the countermovement jump (CMJ) and responded to filmed sequences of offensive play under two distinct environmental temperatures (i.e., mild environment temperature- 20°C and 30% rh versus hot environment temperature- 38°C and 80% rh), interspersed by 1-week interval. Linear mixed models were used. CMJ performance declined following the intermittent protocol on both temperature conditions (p < 0.05). Moreover, there were significant main effects for protocol on CMJ speed (m/s) (p = 0.001; ηp 2 = 0.12), CMJ power (p = 0.002; ηp 2 = 0.11), and CMJ Heightmax (p = 0.002; ηp 2 = 0.12). After performing the intermittent protocol, exposure to a hot temperature caused a greater decline in anticipation accuracy (mild temperature = 64.41% vs. hot temperature = 53.44%; p < 0.001). Our study shows impaired performance in elite female football players following an intermittent protocol under hot compared with mild environmental conditions. We report decreased performance in both CMJ and anticipation performance under hotter conditions. The results reveal that exposure to hot temperatures had a negative effect on the accuracy of their anticipatory behaviors. We consider the implication of the work for research and training interventions.

Identification and Pathogenicity of Species Isolated from Stored Potato Tubers Showing Symptoms of Dry Rot Disease

AbstractDisease arises during the storage of potatoes as a result of pathogens introduced during growing and harvest of the tubers. In this study, the causative fungi of domestic potato dry rot disease were identified, and their pathogenicity was confirmed. A total of 76 species were isolated from 93 potato necropods collected from samples inoculated with dry rot disease. These 76 isolates were identified as Fusarium boothii, F. circinatum, F. citricola, F. foetens, F. iranicum, F. longifundum, F. oxysporum, F. pseudoanthophilum, F. solani, Botryotinia ranunculi, Clonostachys rosea, and Humicola nigrescens. The average size of the inoculation site was ≥ 4.6 mm in F. oxysporum and F. solani, which were pathogenic to dry rot in potatoes but were not pathogenic compared to other strains up to 5 weeks in a 15 to 20 °C and 99% RH environment. The pathogenicity of F. foetens and F. pseudoanthophilum was related to a strong relationship by forming a single system with F. oxysporum. However, except for F. oxysporum and F. solani, these strains have not yet been reported to be associated with dry rot disease. Additionally, the length of the cross-section and longitudinal section of the potato damage symptom inoculated with C. rosea increased the most among all strains. This suggests that C. rosea is the dominant species involved in domestic potato dry rot disease. By contrast, there are no reports of the involvement of B. ranunculi and H. nigrescens in dry rot disease. Therefore, these strains can be seen as parasitic using potato sclerosis as nutrients in in vivo experiments through wounds and are not directly related to dry rot disease.

Hydrothermal aging of carbon fiber reinforced polymer rods intended for cable applications in civil engineering

Carbon fiber reinforced polymer (CFRP) composites have become increasingly popular due to their high strength-to-weight ratio and excellent mechanical properties. However, CFRP composites are susceptible to hydrothermal aging when used as cable applications in civil engineering, which can cause irreversible damage to their service performance. In this study, the effects of water immersion (water@60 °C), constant temperature and humidity exposure (95%RH@60 °C), and alternating hydrothermal environment (12h_60 °C&12h_25 °C@95%RH) were investigated on the property degradation of the CFRP rods. In addition, the water absorption behavior, and thermal and mechanical properties of the CFRP rods were systematically analyzed and compared. We found that elevated temperature and humidity accelerated the water absorption process, resulting in to the higher equilibrium moisture content and diffusion coefficient. Hydrothermal exposure led to maximum degradation in the tensile strength, three-point bending strength and short-beam shear strength of CFRP rods, with values reaching 4.8%, 17.4% and 24.3% in the water@60 °C, 95%RH@60 °C, and 12h_60 °C&12h_25 °C@95%RH conditions, respectively. Among the three mechanical performance properties analyzed, the tensile strength degradation of the CFRP rods was least affected by the three environmental conditions, primarily due to the tensile direction along the carbon fibers. In addition, the three-point bending and short-beam shear strength values of the CFRP rods showed the greatest degradation in the 12h_60 °C&12h_25 °C@95%RH environment. The long-term effects of the water molecules against the CFRP rods in the hydrothermal environment caused resin hydrolysis and debonding of the fiber-matrix interface, leading to degradation in three-point bending and short-beam shear strength. Additionally, the temperature alternating factor accelerated the degradation of the mechanical properties of the CFRP rods, and the mechanical properties of the CFRP rods declined most noticeably with alternating temperatures under the same moisture content conditions.

Degradation mechanism of LiNi0.8Co0.1Mn0.1O2 cathode after ambient storage and self-repairing strategy by electrolyte additive

As a next-generation cathode material for lithium-ion batteries, the LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode undergoes significant performance degradation after ambient storage, hindering its commercial development. Herein, the failure mechanism of the stored NCM811 material was elaborately investigated from the perspective of electrolyte/electrode interfaces. The result manifests that the impurities generated on the NCM811 surface during the storage are mainly LiOH and Li2CO3, accompanied by a few transition metals-based hydroxides and carbonates. These substances can readily catalyze the oxidative decomposition of electrolytes through electrochemical pathways, which should be the main culprit for the fast capacity fading. The adverse effects of surface impurities can be effectively eliminated after introducing a Lewis acid additive into traditional liquid electrolytes. The multifunctional electrolyte additive in the electrolyte firstly serves as an anion receptor to induce the dissolution of contaminants. Then it constructs a stable electrode/electrolyte interphase film to isolate these detrimental substances from electrodes. The NCM811 cathode, after 1-day storage at an 80% RH environment, is almost completely recovered in the additive-containing electrolyte, maintaining a capacity retention rate of 80% after 100 cycles (44% for the baseline electrolyte). The practicability of this strategy is verified by graphite||NCM811 pouch cells, which exhibit superior cyclability than the pristine cell without storage. This work not only reveals a novel insight into the mechanism underlying the degradation of nickel-rich materials following ambient storage but also offers a viable strategy for self-repairing moderately degraded materials, which is of profound commercial significance.

Heat strain while wearing pesticide protective clothing in hot environments: Effects of textile physical properties and ambient humidity

The purpose of this study was to investigate heat strain while wearing pesticide protective clothing (PPC) with different physical properties in hot environments. Eight young males participated in the following three PPC conditions [polyester/cotton work clothing (IT = 1.26 clo, Ret = 42.0 m2·PaW−1), Tyvek coverall (1.16 clo, 47.5 m2·PaW−1), and commonly used nylon suit with a microporous membrane (1.42 clo, 54.1 m2·PaW−1)] and in two environmental conditions (32 °C with 50% RH and 32 °C with 80% RH). All physiological variables (rectal and mean skin temperature, heart rate, and physiological strain index) and most subjective perceptions showed greater values in the 80% RH than in the 50% RH environment (all p < 0.05). Physiological burden was greater in the commonly used nylon suit condition than in the polyester/cotton work clothing condition (all p < 0.05), but in many variables there were no statistical differences between the Tyvek and nylon suit condition, especially in the 80% RH environment. There were no differences in humidity sensation during exercise among the PPC conditions, whereas, during recovery, subjects felt more humid in the Tyvek or nylon suit than in the polyester/cotton work clothing condition (p < 0.05). These results indicate that the 30%-higher humidity induced a greater physiological burden. However, physiological or subjective burden would not always be proportional or inversely proportional to the physical property level of PPC but was affected more by heat exchange modes between the human body and ambient environments.

N-donating and water-resistant Zn-carboxylate frameworks for humid carbon dioxide capture from flue gas

Carbon capture from flue gases is one of the crucial routines for reducing current CO2 emissions and mitigating the greenhouse effect. Metal-organic frameworks (MOFs) have received a lot of interest as efficient solid adsorbents for CO2/N2 separation in flue gas treatment. However, many MOF materials are susceptible to the presence of water vapor, which has a significant impact on their adsorption efficacy and moisture stability. Here in this work, we reported two pillar-layered Zn-MOFs with N-donors, i.e., Zn2(TRZ)2(Fuma) and Zn2(TRZ)2(BDC), which demonstrated high CO2 uptakes (3.92 and 1.52 mmol/g) and CO2/N2 (132 and 20.5) adsorption selectivities at 298 K and 101 kPa, among the best comprehensive results reported by far. After seven days of exposure to a 100 % RH environment, it was found that, the Zn-N pillar contributes to the robust structure of MOFs. Furthermore, in-depth theoretical calculations indicated the guest-framework interactions, and dynamic sorption tests confirmed high working capacities (2.78 and 1.14 mmol/g), sufficient water stability and remarkable cycling performance of the studied MOFs under humid ambient conditions. We believe this work provides a routine to prepare robust and promising candidates to address the challenge in carbon capture under humid conditions.

Electron transport interface engineering with pyridine functionalized perylene diimide-based material for inverted perovskite solar cell

Charge-transport layer engineering is proved to be as important as the optimization of perovskite light harvesting layer in achieving high power conversion efficiency for the inverted perovskite solar cells (p-i-n PSCs). This work mainly focuses on electron transport interface engineering and demonstrates a pyridine functionalized perylene diimide-based electron transport material (ETM), termed SFX-Py-PDI2. Benefiting from the high electron mobility, suitable energy arrangement and defect passivating effect, p-i-n PSCs with SFX-Py-PDI2 as ETM produce a desired PCE over 19% surpassing PC61BM based devices. Especially noteworthy is that introducing SFX-Py-PDI2 into perovskite film through anti-solvent treatment together with PC61BM as ETM further boost the PCE of p-i-n PSCs over 21%. Moreover, the SFX-Py-PDI2 based device showed impressive long-term stability at unencapsulated condition, maintaining over 80% initial PCE after aging for 1000 h in 65 ℃, 50–60% RH environment.

A flexible humidity sensor based on self-supported polymer film

Self-supported polymer films were fabricated by the thiol-ene click cross-linking reaction in this work. The cross-linked frameworks were used to guarantee the stability the films. The hydrophilic monomer with different contents were introduced into the self-supported thick films and uniformly dispersed in the polymer frameworks. The interdigitated electrodes were screen printed with silver paste on the self-supported films to obtain humidity sensors. Herein, the self-supported film acts as both the sensor substrate and the humidity-sensing material. The humidity sensing performances of the obtained sensors were systematically researched. By optimizing the ratio of hydrophilic monomer in the polymer films, the sensitivities of the sensors were enhanced from 1.58 to 103.75 (in the humidity from 11% RH to 95% RH), the response under low RH environment was significantly improved with good linearity. The response/recovery times of the sensor within the humidity range are measured to be 12.5 s and hundreds of seconds. The prepared flexible sensors possess certain mechanical properties, and exhibit good stability under bending and long-term tests up to 60 days. The applications of the as-prepared sensor in the detection of non-contact human skin humidity, human respiration and relative humidity of green plant were explored. The sensor shows excellent sensing performance in various applications and indicates the potential application in wearable and multifunctional devices.

Study on the barrier properties and antibacterial properties of cellulose-based multilayer coated paperboard used for fast food packaging

Some petroleum-based packaging materials have a series of safety issues, and as a result, people are more inclined to use biodegradable and nontoxic packaging materials for foods. However, biodegradable alternatives often need to be modified to overcome their own shortcomings. In this paper, carboxymethyl chitosan (CMCS)/carboxymethyl cellulose sodium (CMC) + polylactic acid (PLA) nano zinc oxide (ZnO) nanoparticles (CMCS/CMC + PLA/ZnO NPs) multilayer coated paperboard was prepared to explore its potential use in food package applications. The multilayer CMCS/CMC + PLA coating reduced the oxygen transmission rate by 99% and doubled the barrier properties for soybean oil penetration and water vapor compared with a single PLA coating layer in a 23 °C/50 RH environment. The oil resistance time of the multilayer CMCS/CMC + PLA coating also increased 28 times, and the water vapor barrier properties increased twofold compared to a single CMCS/CMC coating layer. The water vapor barrier properties increased by a factor of 3 even at 38 °C/90 RH. Compared with the CMCS/CMC + PLA coating without nanoparticles, the barrier performance of the CMCS/CMC + PLA/ZnO NPs coating was further improved. The oxygen, water vapor, and heptane vapor barrier properties all doubled, and the oil resistance time reached 235 h. While a corona treatment reduced the polar component content in the CMCS/CMC coating and led to a slight decrease in the barrier properties of the coating to heptane, it was still a good oil-repellent coating overall. The antibacterial activity (A) toward Escherichia coli and Staphylococcus aureus exceeded 2, which meant that the multilayer coating with 1.5% added ZnO NPs reduced the growth of bacteria by more than 99%. The multilayer coated paperboard created here with the blended and modified materials significantly improved the barrier and antibacterial properties, suggesting that multilayer coatings prepared from degradable materials have good commercial prospects as fast food packaging.

Voluntary Cooling during Exercise Is Augmented in People with Multiple Sclerosis Who Experience Heat Sensitivity.

We tested the hypothesis that people with multiple sclerosis (MS) who experience heat sensitivity voluntarily engage in cool-seeking behavior during exercise to a greater extent than healthy controls. In a 27.0°C ± 0.2°C, 41% ± 2% RH environment, seven participants with relapsing-remitting MS who exhibited heat sensitivity and seven healthy controls completed two randomized trials cycling for 40 min (EX) at 3.5 W·kg-1 metabolic heat production, followed by 30 min recovery (REC). In one trial, participants were restricted from engaging in cooling (CON). In the other trial, participants voluntarily pressed a button to receive 2 min of ~2°C water perfusing a top (COOL). Mean skin and core temperatures and mean skin wettedness were recorded continuously. Total time in cooling provided an index of cool-seeking behavior. RPE, total symptom scores (MS only), and subjective fatigue (MS only) were recorded every 10 min. Core temperature (+0.5°C ± 0.1°C) and skin wettedness (+0.53 ± 0.02 a.u.) increased but were not different between groups or trials at end exercise (P = 0.196) or end recovery (P = 0.342). Mean skin temperature was reduced in COOL compared with CON at end exercise (P ≤ 0.002), with no differences between groups (P ≥ 0.532). MS spent more total time in cooling during EX (MS, 13 ± 3 min; healthy, 7 ± 4 min; P < 0.001) but not REC (MS, 2 ± 1 min; healthy, 0 ± 1 min; P = 0.496). RPE was greater at end exercise in MS (P = 0.001). Total symptom scores increased during exercise (P = 0.005) but was not different between trials (P = 0.321), whereas subjective fatigue was not attenuated in the cooling trial (P = 0.065). Voluntary cooling is augmented in MS but does not consistently mitigate perceptions of heat-related symptoms or subjective fatigue.

24‐4: Research on Water Vapor Penetration of OLED Encapsulation

This paper studied the characteristics of OLED encapsulation film, the test method of water vapor penetration and improving the ability of water vapor barrier. It was found that the group changes after hygroscopic, transferred to Si‐O bond. Based on this mechanism, the test method of water vapor penetration was studied. The average water vapor penetration rate P of film A and film B was about 0.14nm/h and 34nm/h respectively at 85 °C /85%RH environment by TOF‐SIMS and XPS test. At the same time, the permeability lag phenomenon was found. The enhancement effect of inter‐layer structure on water vapor barrier ability was further studied.

Influence of temperature and humidity on the fatigue behaviour of adhesively bonded CFRP/aluminium alloy joints

ABSTRACT To further promote the use of composite bonded structures in engineering applications, it is necessary to understand the change law of the fatigue performance in the long-term server process. This paper investigated the effect of temperature and humidity on the fatigue behaviour of adhesively bonded CFRP/aluminium alloy joints using an experimental method. The quasi-static tensile and fatigue tests of CFRP/aluminium alloy butt joints were carried out at 20 °C, 40 °C, 60 °C and 80 °C, as well as at different ageing times of the 60 °C/95% RH hygrothermal environment. The results demonstrate that with increasing test temperature, the fatigue performance of the adhesive joints decreases substantially, especially when the temperature is close to or higher than Tg of the adhesive (similar to the static failure strength). In the 60 °C/95% RH environment, the fatigue performance of the joint decreases as the ageing time increases, and the fatigue strength decreases more obviously in the early ageing stage. In the single logarithmic coordinate system, the S-N curves at different temperatures/ageing times both conform to the linear law. The function of the stress-temperature/ageing time-number of the cycles to failure was established to help understand the influence law of the environment on the fatigue characteristics of joints and provide a reference for the prediction of the fatigue performance of adhesively bonded joints exposed to a hygrothermal environment.

Study of changes in physical and chemical properties of corn during drying and storage process using a modified in-store dryer

In-Store Dryer (ISD) is a dryer with a convective system for grain that also serves as a storage. This research was conducted to study the effect of drying and storage—In-Store Dryer (ISD) on maize's physical and chemical properties. Carried out a 200 kg maize capacity test with 60 cm material stack thickness divided into three layers of piles with a thickness of each layer is 20 cm. Drying occurs at the average drying temperature of 38,6°C with an average RH environment of 76,8% and an average RH of dryer space of 52,2%. Drying for 32 hours using ISD can dry the maize with the pre-drying material's initial moisture content of 20.14% to 13.56%, the right water content for storage. The drying process can affect ash, fat, protein, and maize fiber's physical and chemical composition. The chemical composition on the pre-drying are: Ash content 0,72%, Fat content 5,62%, Protein 7,64% and Fiber 2,81%. The maize's chemical components undergo post-drying change to become: Ash content 0,8%, Fat content 5,11%, Protein 7,82%, and Fiber 2,52%. The changing of all components is affected by temperature during the drying process, causing a decrease in water content, affecting other chemical components. The analysis result of maize's nutritional components after drying and storage for 30 days using the In-Store Dryer can maintain maize quality. The analysis result of each component that is the Water Content 11.98%, Ash 1.13%, Fat 5.03%, Protein 8, 05%, and 1.8% fiber, and this is by the provisions of SNI 01-4483-1998 for animal feed.

Calculating moisture emissivity of timber members with different surface treatment

Mechanical property and durability of timber members is significantly affected by their surface moisture emissivity which determines the rate they exchange the moisture with the surrounding air. The surface moisture emissivity depends on various parameters including the air flow rate, the temperature and the surface treatment. However, there currently lacks a suitable method for measuring it in the actual working environment of the timber structures. This paper proposes such a method which can identify the surface moisture emissivity factor for timber members with different kinds of surface treatment in their unsteady moisture transfer process. The method is based on Bayesian updating of the numerical model of moisture transfer process of the wood based on the overall weight change. The numerical model considers coupled transfer of the vapour and the bound water. Influences of the sorption hysteresis were also included. Using the method, moisture emissivity factor of different kinds of timber surfaces can be measured by weighting their small-sized samples exposed to ambient climate. Steady moisture transfer process, controlled temperature and RH environment, or the information of the moisture gradient in the samples are not required. Using the method, surface moisture emissivity factor of a pine wood was determined without and with different kinds of surface paint. The measured factor was validated by additional experimental data.

Effects of exercise in hot and humid conditions and bovine colostrum on salivary immune markers.

The purpose of this study was to examine the effects of exercise in a hot and humid environment on salivary lactoferrin and lysozyme. A secondary aim was to quantify the effects of 14-day bovine colostrum (BC) supplementation on salivary lactoferrin and lysozyme at rest and following exercise in hot and humid conditions. Using a randomized, double-blind, and counterbalanced design, ten males (20±2 years, VO2max 55.8±3.7mLkg-1min-1, 11.8±2.7% body fat) ran for 46±7.7minat 95% of ventilatory threshold in a 40°C and 50% RH environment after 14-days of supplementation with either BC or placebo. Saliva was collected pre, post, 1-h, and 4-h post exercise, and was analyzed for lactoferrin and lysozyme using ELISA. There was an immediate increase in the concentration and secretion rate of lactoferrin and lysozyme (p<0.05) with exercise, but BC had no effect (p>0.05). Saliva flow rate was not different between conditions [(PLA: pre: 0.54±0.3, post: 0.44±0.3, 1-h: 0.67±0.3, 4-h: 1.0±0.4mLmin-1); (BC: pre: 0.58±0.2, post: 0.37±0.1, 1-h: 0.63±0.2, 4-h: 0.83±0.4mLmin-1)]. There were no differences in thermoregulatory markers (core temperature or physiological strain index) between BC and placebo trials. Interestingly, exercise-induced heat stress did not impair mucosal immune parameters, instead participants showed a transient increase in salivary lactoferrin and lysozyme. Further, 14-day BC supplementation had no effect on mucosal immunity at any time point.

Investigation of drying shrinkage of alkali-activated cement paste

This project studied the drying shrinkage of alkali-activated cement paste exposed to 75%RH environment, considering the effects of types (i.e. NaOH, Na2SO4, and CaSO4) and dosages (i.e. 1M, 2M, and 5M) of alkali activators. In this work, the length and weight changes of ‘mini-bar’ samples were measured to evaluate the degree of drying shrinkage for each group. Through comparing the results of the pastes mixed with different alkali salts, it has been found that drying shrinkage was usually exaggerated due to the addition of alkali salts. However, when mixed with 5M NaOH, OPC paste showed fewer shrinkage strains (even volume expansion) and weight increase, which was caused by water absorption from the ambient environment.

Preserving the Female Genome in Trehalose Glass at Supra-Zero Temperatures: The Relationship Between Moisture Content and DNA Damage in Feline Germinal Vesicles.

Maintaining a stable dry state is critical for long-term preservation of live biomaterials at suprazero temperatures. The objective of the study was to characterize the effect of moisture content on DNA integrity within the germinal vesicle (GV) of feline oocytes following dehydration and storage at 22-24°C. Using microwave-assisted drying, conditions that led to a predictable and stable moisture content in trehalose solutions were determined. To explore moisture content stability during storage, trehalose samples were dried for 15 min and stored in glass vials at 11 or 43% RH for 8 weeks. To examine whether this condition allowed proper storage of GVs, permeabilized cat oocytes were incubated in trehalose for 10 min and dried for 15 or 30 min. Oocytes then were rehydrated to assess DNA integrity either directly after drying or after 8 weeks of storage in an 11% RH environment. Raman spectroscopy was used to identify the states of dried samples during storage. Moisture content was stable during the storage period. There was no significant difference in DNA integrity between fresh and dried samples without storage. After 8 weeks of storage, DNA integrity was maintained in GVs dried for 30 min. Samples dried for 15 min and stored were compromised, suggesting crystallization of the preservation matrix during storage. Biostabilization was optimal when samples were directly processed to moisture contents consistent with storage in the glassy state. Microwave-assisted drying processing and storage conditions were optimized to ensure stable long-term storage of structural and functional properties of genetic resources.

Voluntary Cooling During Exercise Is Augmented In Heat Sensitive People With Multiple Sclerosis

PURPOSE: Body cooling improves exercise tolerance in heat sensitive people with Multiple Sclerosis (MS). The effectiveness of cooling modalities in real-world settings requires appropriately engaging in cooling behavior. We tested the hypothesis that people with MS voluntarily engage in cooling behavior during exercise to a greater extent than healthy controls. METHODS: In a 27.0±0.2°C, 41±2% RH environment, 7 subjects with relapsing-remitting MS who exhibited heat sensitivity (34±7y, 167±5cm, 72±15kg, EDSS: 1.9±0.8, 1 male) and 7 healthy subjects (CON, 37±7y, 168±7cm, 71±11kg, 1 male) completed two randomized trials cycling for 40 min (EX) at a fixed rate of metabolic heat production (3.5 W/kg) followed by 30 min recovery (REC). In one trial, subjects were restricted from engaging in cooling (NONE). In the other, subjects pressed a button to receive 2 min of ~2°C water perfusing a suit top as often as desired (COOL). Mean skin (Tsk, 8 site) and core (Tcore, telemetry pill) temperatures and mean skin wettedness (Wsk, 8 site) were recorded continuously. Total voluntary time in cooling provided an index of cooling behavior. Ratings of perceived exertion (RPE), composite heat sensitivity symptom scores (HSSS, MS only) and subjective fatigue (MS only) were recorded every 10 min. RESULTS: Tcore (+0.5±0.1°C, P<0.01) and Wsk (+0.52±0.02 a.u., P<0.01) increased in EX and remained elevated in REC (P<0.01) but were not different between trials (P≥0.35) or groups (P≥0.60). Tsk decreased in MS COOL compared to MS NONE from min 20 EX to 5 REC (P≤0.02). There were no other differences in Tsk (P≥0.25). MS spent more total time in cooling in EX (MS: 13.4±3.0 min; CON: 7.4±3.6 min, P<0.01) but not REC (MS: 1.7±1.4 min; CON: 0.3±0.7 min, P=0.40). In both trials, RPE was higher in MS vs. CON (P<0.01). HSSS increased in EX (P<0.01) but was not different between trials (P=0.25). Subjective fatigue was not different between trials in EX (P≥0.97) but was lower at 10 and 20 min of REC in COOL (P<0.02). CONCLUSIONS: MS engaged in body cooling during EX to a greater extent than CON. While cooling did not affect HSSS or fatigue during EX, MS reported greater reductions in fatigue following exercise when cooling was permitted. Cooling during exercise could improve exercise participation and adherence. Supported by: ACSM Foundation Research Endowment Grant