Water Immersion Research Articles

A Pharmacotherapeutic Approaches for Managing Labour Pain using Synthetic Drugs and Natural Therapies.

The birth of a child is a critical and potentially traumatic experience for women, entailing multiple physiological and psychosocial changes. The psychological effects of childbirth pain can have both immediate and long-term effects on the mother's health and her bond with her child. Many studies investigated the different ranges of synthetic drugs available for pain control in labour, inclusive of neuraxial analgesics, inhaled analgesics, and various opioids. The inadequate efficacy and unfavourable side effects of these synthetic drugs prevent appropriate pharmacotherapy, resulting in a quest for natural therapies for reducing labour pain. Herbal therapies (aromatherapy) using several essential oils obtained from various natural plants are another alternative that calms and manages the mind and body through aromatic compounds that have neurological and physiological effects. The review discussed the safety profile of various synthetic drugs with their dosage information and also deliberated on the mechanism and safety profile of various natural plants that are used in aromatherapy. The review also briefly highlighted the other non-pharmacological miscellaneous techniques such as TENS, hypnosis, immersion in water, acupuncture, massage, and different other tactics that aim to assist women in coping with pain in labour.

Water-Soluble, Self-Healing, and Debonding Primer for the Interface between Silicone Leather and Polydimethylsiloxane Composites.

The exceptional hydrophobicity and antifouling properties of polydimethylsiloxane (PDMS) composites have attracted extensive interest as a result of low surface energy. However, PDMS composites are hardly bound by common primers, greatly limiting their practical applications. To address this issue, an EPMS/VTMS (EV) primer synthesized by hydrolytic polycondensation of 3-[(2,3)-epoxypropoxypropyl]methyldiethoxysilane (EPMS) and vinyltrimethoxysilane (VTMS) in acidic conditions is proposed. Interestingly, the EV primer exhibits exceptional reactivity, self-healing capabilities, and strong adhesion to various substrates, including metals, plastics, and glass. The bonding aluminum plates are easily debonded by immersion in water without any residue left. Subsequently, the EV primer has been applied to the interface between silicone leather and the PDMS composite. Results show that the bonding strength for the silicone leather coated with the EV/PDMS composite is 16 times higher than that of the silicone leather modified with the PDMS composite. Meanwhile, the modified silicone leather exhibits impressive antifouling performance, including aqueous and oily stains, appreciable breathability, and excellent wear resistance, even if suffering from 20 000 cycles of abrasion. These excellent advantages for the modified silicone leather should be attributable to the synergistic effect of the EV primer and the PDMS composite. These findings pave the way to develop an ecofriendly debonding primer for PDMS composites, greatly facilitating applications of silicone leather.

Mixture composition design of magnesium oxychloride cement-stabilized crushed stone materials applied as a pavement base

Conventional binding materials, such as silicate cement and lime, present high energy consumption, pollution, and carbon emissions. Therefore, we utilize crushed stone as a stabilization material. Magnesium oxychloride cement (MOC) is modified and used as an inorganic admixture owing to its eco-friendly nature and low carbon content. We analysed the control indicators of an integrated design of MOC-stabilized crushed stone by conducting unconfined compressive strength and water-resistance tests. The optimum mixing composition of the MOC-stabilized crushed stone was determined through the response surface methodology. We determined the best approach and dosage for improving the water resistance of MOC-stabilized crushed stone by comparing the effects of four modification methods: fly ash, citric acid + silica fume, phosphoric acid + waterborne polyurethane, and dihydrogen phosphate potassium salt. We also perform a comparison with 5% ordinary silicate cement-stabilized crushed stone. The results indicate that the MOC-stabilized crushed stone exhibits a rapid increase in strength in the early stage, but this rate reduces after 28 days. The mixing design employs the 4-day unconfined compressive strength and 1-day water resistance coefficient as the technical indicators. The best mixing composition includes a 4.27% MOC dosage and a molar ratio of MgO/MgCl2 of 5.85. We use 1% citric acid + 10% silica fume in equal amounts to replace the MOC dopant method for composite modification of the MOC stabilized crushed stone. Consequently, the 1-day water resistance coefficient before water immersion is significantly increased from 0.78 to 0.91 and its 4-day unconfined compressive strength is only reduced by 0.10 MPa. This significantly improves the water resistance of the MOC-stabilized crushed stone and ensures that its strength remains unaffected, which is the optimal modification method. However, this method must ensure that a small amount of citric acid and silica fume are uniformly distributed in the MOC-stabilized crushed stone, which increases the construction difficulty of the road base.

Evaluating the Impact of Environmental and Operational Conditions on the Characteristics of CFRP Epoxy Composites

The purpose of this study is to determine the material properties of CFRP composites in the form of a fabric for the construction of racing car bodywork. This work focused on the determination of the strength and tribological properties as well as investigating the effects of the operating environment on the developed material. Three material variants, differing in the number of layers used to produce the reinforcement, were used in this study. The tests were carried out on two-/three-/four-layer sheets produced by infusion. Due to the later use of the tested composites for the sheathing of a racing car, the results obtained were analysed in terms of the most favourable strength properties while keeping the weight as low as possible. In this study, the hardness, impact strength, and tensile and bending stresses of the developed composites were examined. In addition to the strength properties, the density, the effects of immersion in water, and the composite’s resistance to staining and friction in the presence of aggressive media were also checked. The structure and the breakthroughs resulting from the strength tests were observed using a stereoscopic microscope. The material’s resistance to sunlight and UVB was also tested.

Effects of Hydrotherapy on the Management of Childbirth and Its Outcomes-A Retrospective Cohort Study.

The main objective of this study was to generate further evidence on maternal and birth outcomes associated with the use of hydrotherapy during labor, specifically aiming to describe the effects of water immersion during all stages of labor (first, second, and third) on women. A retrospective cohort study was carried out on a random sample of women who gave birth at the Costa del Sol Hospital between January 2010 and December 2020. The calculated sample size was 377 women and the data were extracted from their partograms. After data extraction, two groups were formed: one group used hydrotherapy during childbirth (n = 124), while the other group included women who did not use hydrotherapy during the childbirth process (n = 253). The results highlight significant differences in pain perception, analgesia use, types of labor, and delivery times between the two groups. Women who did not use hydrotherapy reported higher pain perception, with a median (IQR) of 8 (7-9) on a numerical scale, compared to a median (IQR) of 6 (5-7) for the hydrotherapy group. Furthermore, the group without hydrotherapy required epidural analgesia in 40% of cases, while in the hydrotherapy group, it was only necessary in 20%. In terms of the type of delivery, the hydrotherapy group had more spontaneous vaginal deliveries compared to the non-hydrotherapy group, which had more operative vaginal deliveries. The overall duration of labor was longer in the hydrotherapy group, especially in women who arrived at the hospital late in labor. Hydrotherapy is associated with a longer time to delivery. Women with a higher pain tolerance tend to opt for hydrotherapy instead of epidural analgesia.

Use of Ozone as a Substrate Treatment for the Control of Trichoderma in the Production of Pleurotus ostreatus.

Pleurotus ostreatus is one of the most widely cultivated species in the world. It can be produced in many lignocellulosic substrates after carrying out a treatment to eliminate competing microorganisms. The most commonly used is pasteurization by steam or by immersion in hot water. The aim of this work is to evaluate if ozone can be employed as treatment for decontamination of the substrate used for the production of the edible mushroom P. ostreatus to control of green mold Trichoderma. Wheat straw was employed as a substrate. We used two different methodologies: bubbling ozone into a tank with water and the substrate, and injecting ozone into a closed tank with the substrate inside. Ten treatments were carried out including two treatments with inoculation by a spray of conidia of Trichoderma. The effect of ozone on the conidia was also evaluated. We found that the treatment of the substrate with ozone in immersed water resulted more effective (lower growth of Trichoderma) than injecting ozone into a closed tank. Anyway, we found that the contaminant fungi could grow on the substrate in both treatments with ozone. We observed that although ozone affected the conidia when it was bubbled into water, some of them still managed to survive and could germinate 72h later. P. ostreatus could grow and produce fruiting bodies on a substrate that was previously treated with ozone and yields were not affected. Based on the results obtained, we conclude that ozone may not be an effective agent to control Trichoderma in highly contaminated substrates, at least in the experimental conditions that we used, for the production of P. ostreatus.

Effects of multiple cold-water immersion during pre-season on recovery performance in under-20 male soccer players: A randomized controlled trial

IntroductionThis study was designed to evaluate the effects of multiple cold-water immersions performed daily during the preseason period on biochemical, clinical, and neuromuscular aspects of muscle damage of soccer players. MethodsThis two-arm, prospectively registered, randomized controlled trial, blinded to statistician and assessors, was conducted at professional football club facilities. Twenty-three under-20 semi-professionals male soccer players were randomly allocated into cold water immersion group (bathtub with water and ice at 10 °C ± 1 °C for 10 min) or control group (rest for 10 min), every day, after training sessions during a preseason. Primary outcome was change in creatine kinase (CK) concentration, and secondary outcomes were changes in vertical jump performance, strength and perception of recovery at baseline (T0) and after protocol training (T1). ResultsAnalysis of Covariance (ANCOVA) showed a statistically significant time-group interactions for CK concentration, with an average reduction of 280.39 U/L (CI95% = −519.14, −41.64; d = 0.55) in the cold-water immersion compared to the control group. No differences between groups were observed in any other measures. ConclusionMultiple cold-water immersions at 10 °C for 10 min decreases CK concentration but does not change any clinical and neuromuscular markers of muscle damage in soccer players during a 9-day preseason.

Photoinduced Dehalogenation‐Based Direct In Situ Photolithography of CsPbBr3 Quantum Dots Micropatterns for Encryption and Anti‐Counterfeiting with High Capacity

Fluorescent lead halide perovskite quantum dots (LH PQDs) micropatterns hold great potential for photonic applications. However, current photolithography for LH PQDs micropatterning is hindered by their incompatibility with traditional photolithography methods, which involve development processes using numerous solvents and exhibit poor stability due to the ionic characteristics of LH PQDs. Herein, a direct in situ photolithography to fabricate CsPbBr3 PQDs micropatterns based on ultraviolet‐C light‐driven debromination is developed. Using this approach, fluorescent CsPbBr3 PQDs micropatterns with high theoretical information storage capacity (up to 10750205) can be achieved in a single step, without the need for tedious development processes. Furthermore, the fabricated CsPbBr3 PQDs micropatterns show high stability, remaining undamaged even after immersion in water for 6 months. The combination of excellent optical properties, development‐free process, high stability, and low cost makes the in situ photolithography strategy very promising for patterning LH PQDs toward photonic integrations.

Experimental study on mechanical and hydraulic properties of xanthan gum improved low liquid limit silty soil

The low liquid limit silty soil in the North China plain area is generally unsuitable for direct use as roadbed and slope soil. In order to improve the performance of low liquid limit silty soil, xanthan gum was used as an improver. Through a series of tests, the improvement effect of xanthan gum on low liquid limit silty soil was studied. The test results showed that Xanthan gum as an improver could significantly improve the unconfined compressive strength of silty soil. With the increase in dosage and curing age, the unconfined compressive strength of improved silty soil continued to improve and eventually tended to stabilize. The optimal dosage and curing period were 2% and 7 days, respectively. In addition, Xanthan gum could greatly improve the permeability and disintegration of low liquid limit silty soil. The permeability coefficient of improved silty soil with a content of 0.75% Xanthan gum and a 7-day curing period was 4.73 × 10−4 m·s−1, which was only 1.10% of that of plain silty soil at the same curing period. After immersion in water for 12 h, the soil only experienced slight disintegration. The scanning electron microscope image showed that the gel generated by the hydration reaction of Xanthan gum could improve the compactness and integrity of the soil by filling the voids, thus significantly improving the mechanical and hydraulic properties of the low liquid limit silty soil.

Experimental study on the effect of water-heat-force triple-field coupling on the electrical and fatigue properties of cement stabilized layer power generation pavement

Road piezoelectric energy capture technology has developed rapidly in recent years. However, the research of road piezoelectric energy harvester (RPEH) in road environment has rarely been reported. Therefore, in this study, Cement stabilized layer power generation pavement were prepared. Firstly, the output performance of an RPEH under different environmental factors (load, temperature, and water immersion) was tested through indoor tests. Secondly, the 3D simulation model of cement stabilized layer power generation pavement has established, and the output performance of cement stabilized layer power generation pavement has simulated and analyzed under the coupled environment of water, heat and force. Then, the short-term fatigue performance of the RPEH under harsh environments was evaluated. Finally, the fatigue life of cement stabilized layer power generation pavement under extreme environment is predicted by 3D simulation model. The results reveal that the excitation load is the main factor affecting the electrical energy output of the RPEH; The voltage increase is 204.3 % when the excitation load is increased from 0.26 MPa to 1 MPa. Furthermore, an increase in temperature leads to a decrease in the equivalent force of cement stabilized layer and the effect of stress reduction is affected by water immersion environment; When the excitation load is 0.7 MPa, the temperature increases from 20℃ to 50℃, and the immersed environment is 500, 1000 and 1500 ml, the stress attenuation rates are 0.28 %, 0.34 % and −0.025 %, respectively. The water-immersed environment which attenuates the equivalent force and output voltage by more than 40 % and simultaneously attenuates the enhancement effect of the load and temperature on the voltage output of the RPEH. The short-term fatigue degradation rate of piezoelectric ceramics under high temperature and water immersion is 18.5 %, The accuracy of the 3D simulation model in extreme environment was verified through the comparison between the laboratory test results and the 3D simulation results, and the fatigue life of cement stabilized layer power generation pavement was predicted to be greater than five years. The results of this study provide an important reference for the construction design of RPEH for complex road environments.

The Effect of Myofascial Stretching on Mechanical Nociception and Contributing Neural Mechanisms

Myofascial stretching is often prescribed in the management of musculoskeletal pain. However, the neural mechanisms contributing to a decrease in pain are unknown. Stretching produces a sensation that may act as a conditioning stimulus in a conditioned pain modulation response. The purpose of this study was to compare immediate changes in pressure pain thresholds (PPTs) during a low-intensity stretch, moderate-intensity stretch, and cold water immersion task. A secondary purpose was to examine if personal pain sensitivity and psychological characteristics were associated with the responses to these interventions. Twenty-seven (27) healthy participants underwent a cross-over study design in which they completed a cold water immersion task, upper trapezius stretch to the onset of the stretch sensation, and a moderate-intensity stretch. A significant condition x time effect was observed (F (8,160) = 2.85, p < 0.01, partial eta2 = 0.13), indicating reductions in pain sensitivity were significantly greater during a cold water immersion task compared to moderate-intensity stretching at minutes two and four. Widespread increases in heat pain threshold and lower pain-related anxiety were moderately correlated with the response to the cold water immersion task but not stretching. Moderate-intensity stretching may not elicit a conditioned pain modulation response possibly because the stretch was not intense enough to be perceived as painful.

Impact of Cl- on the performance of magnesium oxysulfate (MOS) cement

As magnesium oxysulfate (MOS) cement finds more applications in the engineering field, the influence of Cl- on the mechanical properties of MOS cement has gained more attention. In this paper, MgCl2·6 H2O served as the source of Cl- to investigate its influence on the evolving properties of MOS cement. The results showed that MgCl2·6 H2O extended the formation time of the 5Mg(OH)2·MgSO4·7 H2O phase, reduced the dispersion of the MOS cement system, and decreased the crystalline size of the 5Mg(OH)2·MgSO4·7 H2O phase (200) crystal plane. The addition of MgCl2·6 H2O had a positive effect on improving flexural strength and increasing the content of gel. During the curing process, the presence of Cl- facilitated the dissolution and recrystallization of Mg(OH)2, altering its growth tendency and promoting the formation of hexagonal crystal Mg(OH)2. During soaking in water, the increased content of MgCl2·6 H2O led to a decrease in the softening coefficient due to the dissolution of excess MgCl2. The structure of the 5Mg(OH)2·MgSO4·7 H2O phase underwent changes as Cl- entered the crystal interior, leading to an increase in the d-spacing of the 5Mg(OH)2·MgSO4·7 H2O phase at the (222) crystal plane. The introduction of Cl- endowed the 5Mg(OH)2·MgSO4·7 H2O phase with the potential to transform into 5Mg(OH)2·MgCl2·8 H2O. Following immersion in water, the modified structure of the 5Mg(OH)2·MgSO4·7 H2O phase retained its relative integrity, resulting in a higher softening coefficient of 0.73 after a 90-day soaking period, attributed to the proper introduction of Cl-.

Stabilization of micaceous residual soil with industrial and agricultural byproducts: Perspectives from hydrophobicity, water stability, and durability enhancement

Micaceous residual soil is prevalent in the tropical regions of southern China. However, it is generally deemed unsuitable as a construction material in earthen structures due to its inferior engineering properties. Despite previous research into stabilizing micaceous soils, there remains an urgent demand for sustainable alternatives to traditional stabilizers to achieve circularity. Furthermore, uncertainties regarding the long-term performance of stabilized soils under hydraulic conditions complicated their use in flood-susceptible areas. To provide a sustainable and low-cost solution for creating stabilized soil for earthen structures in waterlogged regions, this study explores the impact of coir fiber and fly ash, agricultural and industrial byproducts, on the hydrophobicity, durability, and water stability of micaceous residual soil from Hainan, China. The study commenced with the preliminary mechanical tests to ascertain the optimal dosage of coir fiber and fly ash, which were determined to be 1% and 15%, respectively. Then, hydrophobicity, durability, and disintegration tests are conducted on fiber-reinforced fly-ash-treated soil under various stabilization conditions. The microstructural evolution of the soil fabric in response to the stabilization process was meticulously traced using scanning electron microscopy and energy-dispersive spectroscopy. Results indicated that the addition of fly ash could impart severe and persistent water repellency to the studied soil, with the contact angle improving from 16.7° to 102.9°, and the water drop penetration time significantly extending from 3.6 s to approximately 600 s. While incorporating coir fibers into the cemented soil presented negligible improvement on soil hydrophobicity, it markedly enhanced the soil’s durability, mitigated moisture-related deterioration and decelerated disintegration. Notably, the strength residual ratio of fiber-reinforced cemented sample maintained higher than 90% even after 20-day water immersion, and the disintegration rate decreased by 57% compared to unreinforced sample. Microstructural analysis revealed that bonding, friction, and interlocking among fibers, hydration products, and soil particles are the main contributors to the stable and robust matrix, ensuring improved mechanical behavior and longevity of micaceous residual soil. This study provides an innovative method for utilizing waste byproducts in stabilizing micaceous residual soil, as a viable option for earthworks in rain-soaked or flood-prone areas.

Effects of long-term exposure of NSM CFRP-to-concrete bond to natural and accelerated aging environments

Carbon fiber reinforced polymer (CFRP) composites can be used to strengthen existing reinforced concrete (RC) structures. The CFRP laminate can be bonded to RC structure using epoxy adhesive via near-surface mounted (NSM) strengthening technique. However, existing literature generally lacks data about durability of NSM CFRP-to-concrete bond. In this study, strengthened concrete elements were exposed to laboratory-controlled environments (at approximately 20 °C/55 % RH, and water immersion at 20 °C) and natural field environments (to promote natural aging induced mainly by carbonation, high temperatures, freeze–thaw attack, and airborne chlorides) for up to four years. Durability tests were conducted yearly for the bond and its constituent materials. The highest bond strength degradations were nearly 12 % and 9 % for the specimens immersed in water and those exposed to freeze–thaw attack, respectively. Besides, environmental conversion factors of 0.88 and 0.93 were derived from a database of existing accelerated, and natural aging data from the present work, respectively.

The Impact of Dissolved Salts on the Erosion of Physically Purified Compacted Bentonite

Compressed bentonite is an appropriate cushion material for getting rid of spent nuclear waste below the surface storage. The contact of compressed bentonite with water, its immersion in water and subsequently its swelling into the neighboring gaps are the principal processes for the development of colloid fines. In this study, to examine the impact of ionic strength on the erosion of compacted bentonite, only the ionic power values of the water contacting the bentonite were changed by keeping the flow rates constant. Sodium chloride was used to change the ionic power of the water contacting the bentonite throughout the experiment. Turbidity meter (TM) was used to determine the amount of eroded particles. The dissolution of bentonite fragments is critical not only due to their physical stability but also due to the radioactive isotopes they contain. An experimentation methodology is introduced. The implemented flow rates were 0.06 ml/min and 0.22 ml/min, and the selected waters were distilled water and 0.05 M NaCl ionic strength water. The dry densities of the compressed bentonite samples used were 1.67 g/cm3, 1.72 g/cm3, 1.72 g/cm3 and 1.72 g/cm3. With distilled water, the total erosion value measured at the end of the 24th day using a flow rate of 0.06 ml/min was 1002.7 mg, whereas the final erosion value measured at the end of the 24th day using water containing 0.05 M NaCl salt was 31.13 mg. In the case of distilled water, the total erosion value measured at the end of the 24th day using a flow rate of 0.22 ml/min was 1774.85 mg, while the total erosion value measured at the end of the 24th day using water containing 0.05 M NaCl salt was 73.6 mg. This demonstrates that the influence of the ionic strongness of the water on erosion is too important to be neglected.

Natural Light Rechargeable Night Peal-like Coatings for Expressway

Traditional roadway lighting is intended to provide safe guidance for drivers and pedestrians, but the large-scale application of roadway lighting has resulted in significant energy consumption and light pollution. However, road markings prepared by luminous coating are a kind of multi-functional road marking that can meet the needs of highway lighting at night and save energy. Here, CaAl2O4:Eu2+,Nd3+,Gd3+ blue long-afterglow phosphor is obtained by the high-temperature solid-state method, and the blue luminescent coating is synthesized by the blending method. The phase composition, microscopic morphology, luminescence properties and water resistance of the phosphor and luminescent coatings are characterized. The best components and processes of the luminescent coating are explored to meet the application of an expressway. Considering the afterglow’s performance, the optimal calcination temperature of the phosphor is determined to be 1300 °C. The afterglow of the phosphor can be over 8 h after 2 h of daylight excitation. The addition of 1.25% SiO2 to the luminescent coating improves the uniformity of the components, and the incorporation of 3.5% CaCO3 improves the denseness of the coating. When the coating thickness is 0.8mm, the luminescent coating can achieve the best luminous effect. After 120 h of immersion in water, the afterglow intensity of the luminescent coating reduced to 70% of the original, which has excellent water resistance. The blue luminescent coating with the addition of appropriate amounts of CaCO3 and SiO2 improves the dispersion as well as the densification of the components in the coating to achieve the best luminescent effect. In the Shenyang area, different weather conditions (cloudy, sunny, rainy) have no significant effect on the afterglow performance of the luminescent coatings, all of which can achieve over 5 h of afterglow and are suitable for expressways.

Hot head-out water immersion increases internal carotid artery shear rate but does not alter intracranial vascular reactivity to carbon dioxide

Acute head-out water immersion (HOWI) in hot water increases cerebral blood flow (CBF) until core temperature rises by ~1.0°C. The increase in CBF may promote increases in arterial shear rate that could enhance cerebrovascular reactivity to CO2 (CVRCO2) as a result of elevated nitric oxide (NO) bioavailability. An increase in NO bioavailability improves peripheral vasodilator function, and therefore, a similar response may occur in the cerebral vasculature. This likely only aids in cerebral vasodilation during hypercapnia, and not cerebral vasoconstriction during hypocapnia. However, it is unclear if a single session of hot HOWI alters cerebral artery shear rate and CVRCO2 to hyper- and hypocapnia. Purpose: We tested the hypotheses that during a single session of hot HOWI (39°C), cerebral artery shear rate and hypercapnic CVRCO2 would be greater and hypocapnic CVRCO2 would be lower compared to temperate HOWI (35°C). Methods: Eighteen healthy participants (age: 25±5 y, 6 women) completed two experimental visits. Middle and posterior cerebral artery blood velocities (transcranial Doppler; MCAv and PCAv) were continuously recorded. Blood velocities and diameters of the right internal carotid artery (ICA) and vertebral artery (VA) were obtained via dual-mode Doppler ultrasound to calculate shear rate. Hypocapnic and hypercapnic CVRCO2 were assessed in the MCA and PCA during self-paced hyperventilation (until PETCO2 decreased by 10 mmHg from baseline) and during 30 s of 7% CO2 inhalation, respectively. Measures were completed before immersion (PRE) and after a +1.0°C increase in core temperature during hot HOWI and time-matched during temperate HOWI. Data are reported as mean ± SD. Results: There were no differences between conditions at PRE. MCAv (55±9 vs. 64±12 cm/s; P=0.01) and PCAv (29±5 vs. 39±7 cm/s; p<0.01) were lower in hot vs. temperate HOWI at +1.0°C. ICA shear rate was greater in hot vs. temperate HOWI at +1.0°C (247±51 vs. 180±43 s−1; p<0.01) but VA shear rate did not differ between conditions (P=0.78). There were no differences between conditions for hypercapnic CVRCO2 (MCA: P =0.48, PCA: P=0.43) or hypocapnic CVRCO2 (MCA: P=0.18). A condition effect was observed for PCA hypocapnic CVRCO2 (p<0.01), but multiple comparisons did not reveal where differences occurred (all P≥0.10). Conclusion: Hot head out water immersion elicits similar changes in hemodynamics and CVRCO2 in intracranial arteries (i.e., MCA and PCA) as temperate head out water immersion. Hot head out water immersion produces a greater shear rate in the ICA compared to temperate water, which may be beneficial for cerebrovascular health if done recurrently. This study was partially supported by the Mark Diamond Research Fund at the University at Buffalo and the Offce of Naval Research Director of Research Early Career Grant (N00014-17-1-2878). 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.

Fourteen Days of Cool Water Immersion Does Not Modify an Indirect Index of Brown Adipose Tissue Activation

Military divers often operate in cold water eliciting reductions in skin and core temperatures despite the use of thermal protection. Decreases in body temperatures triggers shivering and non-shivering thermogenesis, the latter of which is largely due to the activation of brown adipose tissue (BAT). Ten days of cool air exposure (15-16°C) and seven days of cold-water exposure (14°C) augments non-shivering thermogenesis. However, it is unknown if repeated exposure to cool head out water immersion (CWI) modifies non-shivering thermogenesis. This study tested the hypothesis that fourteen days of CWI for 4 h/d will increase BAT activation. Healthy adults were randomly assigned to either CWI (n=10, 5 women) or thermoneutral head out water immersion (35°C, TNW, n=9, 5 women). CWI and TNW exposures were 4 h in duration and were completed once daily for 14 d in a 16-d period. CWI consisted of the initial immersion in 28°C water and following a 0.5°C reduction in rectal temperature, the water temperature was increased to up to 30°C so that a mild hypothermic state was maintained during the 4 h. Rectal temperature, oxygen uptake (indirect calorimetry), and supraclavicular and trapezius skin temperatures (thermocouples) were measured preexposure and during the middle 3 h of immersion. This analysis was a part of a larger study. Therefore, during the 3 h period, all participants were exposed to hypoxia (FiO2: 0.14). The supraclavicular-trapezius skin temperature difference (Tsk diff) provided an index of BAT activation. Data collected on Day 1 and Day 14 are presented (mean ± SD). Peak decreases in rectal temperature from preexposure were greater in CWI (-0.7±0.3°C) vs. TNW (-0.2±0.4°C, p<0.001) and did not differ between Day 1 and Day 14 in either group (p=0.923). Average oxygen uptake was higher in CWI (0.54±0.09 L/min) vs. TNW (0.38±0.12 L/min, p<0.001) and did not differ between Day 1 and Day 14 in either group (p=0.443). Average Tsk diff did not differ between groups (CWI: 2.2±0.8°C, TNW: 1.6±0.1.1°C, p=0.090) and did not differ between Day 1 and Day 14 in either group (p=0.111). Peak decreases in rectal temperature were significantly correlated with average oxygen uptake (r=-0.552, p<0.001) but not average Tsk diff (r=-0.152, p=0.362). Fourteen days of CWI did not modify thermogenesis (oxygen uptake) nor BAT activation, as estimated from Tsk diff. However, a potential interaction between moderate hypoxia and BAT activation during CWI cannot be excluded. Future work is required to determine the effect of mild hypothermia, such as that experienced by divers operating in cold water even with thermal protection, on more direct markers of BAT activation. Funding: Offce of Naval Research (N00014-20-1-2593 & N00014-21-1-2276). 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.

Construction of cellulose-based hybrid hydrogel beads containing carbon dots and their high performance in the adsorption and detection of mercury ions in water

Cellulose-based adsorbents have been extensively developed in heavy metal capture and wastewater treatment. However, most of the reported powder adsorbents suffer from the difficulties in recycling due to their small sizes and limitations in detecting the targets for the lack of sensitive sensor moieties in the structure. Accordingly, carbon dots (CDs) were proposed to be encapsulated in cellulosic hydrogel beads to realize the simultaneous detection and adsorption of Hg (II) in water due to their excellent fluorescence sensing performance. Besides, the molding of cellulose was beneficial to its recycling and further reduced the potential environmental risk generated by secondary pollution caused by adsorbent decomposition. In addition, the detection limit of the hydrogel beads towards Hg (II) reached as low as 8.8×10-8 M, which was below the mercury effluent standard declared by WHO, exhibiting excellent practicability in Hg (II) detection and water treatment. The maximum adsorption capacity of CB-50 % for Hg (II) was 290.70 mg/g. Moreover, the adsorbent materials also had preeminent stability that the hydrogel beads could maintain sensitive and selective sensing performance towards Hg (II) after 2 months of storage. Additionally, only 3.3% of the CDs leaked out after 2 weeks of immersion in water, ensuring the accuracy of Hg (II) evaluation. Notably, the adsorbent retained over 80% of its original adsorption capacity after five consecutive regeneration cycles, underscoring its robustness and potential for sustainable environmental applications.

Deterioration evolution mechanism and damage constitutive model improvement of sandstone–coal composite samples under the effect of repeated immersion

Underground reservoirs in coal mines, consisting of goafs (By goaf, we mean the space that remains underground after the extraction of valuable minerals), are commonly utilized for mine water storage and drainage, with their primary load-bearing structures being the “roof–coal pillar” systems. Consequently, this structure must endure the repeated immersion behavior resulting from fluctuations in the mine water level, resulting in the risk of geological disasters. This paper analyzes the variation in mechanical properties of sandstone–coal composite samples after repeated immersion cycles through axial loading tests. The results indicate that the water content of the sample exhibits a notable and rapid increase with each successive immersion cycle. This corresponds to a decrease in the stress threshold and modulus parameters of the samples. Moreover, the acoustic emission signals serve as indicators of the softening characteristics of the samples. With the increase in immersion cycles, there is an augmentation in both the frequency and extent of shear cracks. The non-linear failure characteristics of the samples become more pronounced. Consequently, water significantly weakens the cementing material between rock grains. Both sandstone and coal display a decrease in deformation resistance capabilities at a macroscopic level. The constitutive model of the composite sample was improved based on the degradation characteristics of mechanical strength and strain energy parameters, which offers enhanced accuracy in analyzing the degradation process caused by water immersion. This paper offers a crucial theoretical foundation for comprehending the deterioration evolution characteristics of the “roof–coal pillar” bearing structure affected by repeated immersion.