Cooling Water Bath Research Articles

Incorporating Sulfur Atoms into Palladium Catalysts by Reactive Metal–Support Interaction for Selective Hydrogenation

Incorporating Sulfur Atoms into Palladium Catalysts by Reactive Metal–Support Interaction for Selective Hydrogenation

Central and peripheral pain sensitization during an ultra-marathon competition.

Background and aims The participation in ultra-marathons and other ultra-endurance events has increased exponentially over the past decade. There is insufficient data on variation in pain mechanisms in exercise overall but especially in the ultra-endurance athlete population. To further understand peripheral and central pain sensitization we have investigated pressure pain threshold and conditioned pain modulation during three separate ultra-marathon competitions. Methods Each ultra-marathon investigated was held in the state of Florida, USA, over flat, sandy and paved surfaces under generally warm to hot, humid conditions. Pressure pain threshold was measured utilizing a Baseline © Dolorimeter. The blunt end of the dolorimeter stylus was placed onto the distal dominant arm, equidistant between the distal radius and ulna, three times in a blinded manner to insure that the testing technician did not influence the subject's responses. Conditioned pain modulation was measured immediately after the PPT measures by placing the non-dominant hand in a cool water bath maintained at 15°C. The same dolorimeter measurement was repeated two more times on the dominant arm while the non-dominant hand remained in the water. Data was analyzed with a paired t-test. Results Pressure pain threshold was significantly decreased (p<0.05) at 25, 50 and 100 miles. Conditioned pain modulation was also significantly decreased (p<0.05) at 25, 50 and 100 miles of an ultra-marathon competition. Conclusions Together these data suggest an increased peripheral and/or central pain sensitization starting at 25 miles and continuing throughout an ultra-marathon competition run in these conditions. This is the first study that provides evidence of a decreased peripheral pain threshold and decreased central pain inhibition from ultra-marathon running. Decreases in both the peripheral pain threshold and central inhibition may result from nociceptor plasticity, central sensitization or a combination of both. Implications Based on previous research that has indicated a central sensitization resulting from inflammation and the well-documented inflammatory response to the rigors of ultra-marathon competition, we suggest the decreased peripheral pain threshold and decreased descending pain inhibition results from this inflammatory response of running an ultra-marathon.

Getting in shape: Molten wax drop deformation and solidification at an immiscible liquid interface

The controlled production of non-spherical shaped particles is important for many applications such as food processing, consumer goods, adsorbents, drug delivery, and optical sensing. In this paper, we investigated the deformation and simultaneous solidification of millimeter size molten wax drops as they impacted an immiscible liquid interface of higher density. By varying initial temperature and viscoelasticity of the molten drop, drop size, impact velocity, viscosity and temperature of the bath fluid, and the interfacial tension between the molten wax and bath fluid, spherical molten wax drops impinged on a cooling water bath and were arrested into non-spherical solidified particles in the form of ellipsoid, mushroom, disc, and flake-like shapes. We constructed cursory phase diagrams for the various particle shapes generated over a range of Weber, Capillary, Reynolds, and Stefan numbers, governed by the interfacial, inertial, viscous, and thermal effects. We solved a simplified heat transfer problem to estimate the time required to initiate the solidification at the interface of a spherical molten wax droplet and cooling aqueous bath after impact. By correlating this time with the molten wax drop deformation history captured from high speed imaging experiments, we elucidate the delicate balance of interfacial, inertial, viscous, and thermal forces that determine the final morphology of wax particles.

Effect of TEP content in cooling bath on porous structure, crystalline and mechanical properties of PVDF hollow fiber membranes

Poly (vinylidene fluoride) (PVDF) hollow fiber membranes were prepared by adding triethyl phosphate (TEP) to the cooling water bath in a modified thermally induced phase separation process. The effect of TEP content in the cooling bath on the porous structure, crystallinity, thermal and mechanical properties of PVDF hollow fiber membranes was investigated. The melting temperature and crystallinity of the membranes were determined using differential scanning calorimetry. The crystalline and cross‐section morphology of the hollow fiber membranes were investigated using wide angle X‐ray diffraction and scanning electron microscopy. The resulting membrane exhibited a nearly symmetric structure. The results showed that the TEP content in the cooling bath had a crucial role on the membrane formation, which was also confirmed from the morphology and mechanical properties of the hollow fibers. The porosity, average pore size, crystallinity, Young's modulus, max stress, and elongation at breakage of the hollow fiber membranes can be related to the amount of TEP in the cooling bath. Better pore connectivity was obtained in hollow fiber membranes when the weight ratio of TEP to water was 40:60. POLYM. ENG. SCI., 54:2207–2214, 2014. © 2013 Society of Plastics Engineers

The effect of cross-section design of rectangular microchannels on convective steam condensation

This study investigates steam condensation in uniform-cross-section, converging and diverging rectangular microchannels with a mean hydraulic diameter of 117 µm. The steam flow in the microchannel is cooled by directly immersing its bottom and side surfaces in a still, cool water bath. The flow patterns, bubble emission frequency and bubble velocity, two-phase flow pressure drop and temperature drop through a microchannel with three different cross-section designs are presented. Bubble coalescence is observed, and results show that the channel cross section has a significant effect on the two-phase flow pressure drop and channel outlet temperature. In addition, the study concludes that microchannels with a converging cross-section design work best for draining two-phase fluids composed of uncondensed steam and liquid water.

Low temperature-induced sterility in rice: Evidence for the effects of temperature before panicle initiation

Spikelet sterility of rice ( Oryza sativa L.) results from low temperatures during panicle development. However, this temperature alone cannot fully explain the fluctuations in sterility observed in the field, since the susceptibility of rice plants to low temperature often changes according to its physiological status during sensitive stages. In the present study, we examined whether temperatures before the panicle initiation stage (PI) influence the plant's susceptibility to sterility during panicle development. To test this, we conducted a 2-year pot study and an analysis of field data using a model of cooling degree-days (CDD). In the pot study, the air temperature ( T a) and water temperature ( T w) were controlled independently for 3 weeks during the vegetative growth stage before PI. After PI, the plants were submerged in a cool water bath at a critical temperature of 19.5 °C to induce floral sterility. We found that low T w during vegetative growth significantly increased the sterility. Low T a during vegetative growth also significantly increased the sterility, but this effect was diminished by warm T w even at low T a. There was a close and negative correlation between sterility and T w during vegetative growth. In the analysis of field data, we introduced CDD using temperatures below a threshold level of 20 °C to represent the magnitude of the exposure to low temperature from PI to the heading stage. Data of T a was used for this analysis because data of T w was scare. The CDD model was applied to 77 independent data sets collected at nine Agricultural Research Centers during four typical cool summers (1980, 1988, 1993, and 2003) in northern Japan. Year-to-year variations in sterility at one site were roughly accounted for by the variations in CDD, but large deviations were observed among the years. The deviations were related to T a averaged over the 30-day period before PI. For a similar level of CDD, the lower the T a before PI, the greater the sterility. Similar deviations were observed in the between-site relationships between sterility and CDD, and these deviations were related with the T a before PI. These results suggest that temperatures before PI, and especially T w, change the susceptibility of a rice plant to low temperatures during panicle development.

Effect of glycerol content in cooling bath on performance of poly(ethylene-co-vinyl alcohol) hollow fiber membranes

Poly(ethylene-co-vinyl alcohol) (EVOH) is a copolymer of ethylene and vinyl alcohol with an excellent combination of chemical, thermal and mechanical properties. EVOH hollow fiber membranes were successfully prepared by adding solvent (glycerol) to the cooling water bath in thermally induced phase separation (TIPS) process. The effect of glycerol:water ratio on membrane structures and properties including water permeability, solute rejection, and membrane strength were studied. EVOH crystallization is so slow that glycerol in the quench bath was allowed to flow into the membrane, thereby achieving high porosity at the outer surface. Therefore, adding solvent (glycerol) and increasing its content brings about an increase in the water permeability and a decrease in solute rejection. However, the membrane becomes more symmetric and weaker with increasing glycerol:water ratio due to the higher porosity.

A comparison of the effects of preferred music, arithmetic and humour on cold pressor pain

Research studies of ‘audioanalgesia’, the ability of music to affect pain perception, have significantly increased in number during the past two decades. Listening to preferred music in particular may provide an emotionally engaging distraction capable of reducing both the sensation of pain itself and the accompanying negative affective experience. The current study uses experimentally induced cold pressor pain to compare the effects of preferred music to two types of distracting stimuli found effective within the previous studies; mental arithmetic, a cognitive distraction, and humour, which may emotionally engage us in a similar manner to music. Forty-four participants (24 females, 20 males) underwent three cold pressor trials in counterbalanced order. The Paced Auditory Serial Addition Task provided the cognitive distraction and a choice was given from three types of audiotaped stand-up comedy. Participants provided their own preferred music. A circulating and cooling water bath administered cold pressor stimulation. Tolerance time, pain intensity on visual analogue scale and the pain rating index and perceived control were measured. Preferred music listening was found to significantly increase tolerance in comparison to the cognitive task, and significantly increase perceived control in comparison to humour. Ratings of pain intensity did not significantly differ. The results suggest preferred music listening to offer effective distraction and enhancement of control as a pain intervention under controlled laboratory conditions.

Cooling the Foot to Prevent Diabetic Foot Wounds

The etiology of neuropathic diabetic foot wounds can be summarized by the following formula: pressure x cycles of repetitive stress = ulceration. The final pathway to ulceration consists of an inflammatory response, leading to tissue breakdown. Mitigation of this response might reduce the risk of ulceration. This proof-of-concept trial evaluates whether simple cooling of the foot can safely reduce the time to thermal equilibrium after activity. After a 15-min brisk walk, the six nondiabetic volunteers enrolled were randomly assigned to receive either air cooling or a 10-min 55 degrees F cool water bath followed by air cooling. The process was then repeated with the intervention reversed, allowing subjects to serve as their own controls. There was a rise in mean +/- SD skin temperature after 15 min of activity versus preactivity levels (87.8 degrees +/- 3.9 degrees versus 79 degrees +/- 2.2 degrees F; P = .0001). Water cooling immediately brought the foot to a point cooler than preactivity levels for all subjects, whereas air cooling required an average of nearly 17 min to do so. Ten minutes of cooling required a mean +/- SD of 26.2 +/- 5.9 min to warm to preactivity levels. No adverse effects resulted from the intervention. We conclude that cooling the foot may be a safe and effective method of reducing inflammation and may serve as a prophylactic or interventional tool to reduce skin breakdown risk.

Preparation and membrane performance of poly(ethylene- co-vinyl alcohol) hollow fiber membrane via thermally induced phase separation

Poly(ethylene- co-vinyl alcohol) (EVOH) hollow fiber membranes with ultrafiltration performance were prepared from EVOH/glycerol systems via thermally induced phase separation (TIPS). The diluent glycerol was used as bore liquid to make a lumen of the hollow fiber for the purpose of prevention of the diluent evaporation and the larger pores formation at the inner surface of the hollow fiber. The obtained hollow fiber membranes showed asymmetric structures with skin layer near the outer surface, the larger pores just below the skin layer and the smaller pores near the inner surface. The formation of the larger pores near the outer surface was due to the enhanced pore growth by the water penetration. Some primary factors affecting the structure and performance of the membranes such as ethylene content (EC) in EVOH, cooling water bath temperature and take-up speed were studied extensively. The water permeability can be improved by increasing the water bath temperature and the take-up speed and by decreasing the EC. Both the pore size at the outer surface and the connectivity between the pores have to be considered together to understand the experimental result of the water permeability and the solute rejection.

Cardiovascular Responses to the Induction of Mild Hypothermia in the Presence of Epidural Anesthesia

The combining of epidural anesthesia with general anesthesia impairs central and peripheral thermoregulatory control and therefore is often accompanied by unintended intraoperative hypothermia. However, little is known about the cardiovascular response to hypothermia during combined epidural and general anesthesia. The authors assessed the effects of hypothermia during such combined anesthesia. The authors randomly assigned 30 mongrel dogs anesthetized with isoflurane (1.0%) to three groups of 10: control, receiving general anesthesia alone; thoracic injection, additionally receiving thoracic epidural anesthesia; and lumbar injection, additionally receiving thoracolumbar epidural anesthesia. Core temperature was lowered from 38.5 degrees C to approximately 34 degrees C (mild hypothermia) using a femoral arteriovenous shunt in an external cool water bath. During hypothermia, the authors measured heart rate, cardiac output, and plasma catecholamine concentrations in each group. Ejection fraction was also measured using echocardiography. Compared with measurements during baseline conditions (general anesthesia alone with no epidural injection and no hypothermia) in the control, thoracic, and lumbar injection groups, the injections followed by hypothermia produced 17, 32, and 41% decreases in heart rate; 22, 32, and 47% reductions in cardiac output; 66, 85, and 92% decreases in the epinephrine concentrations; and 27, 44, and 85% decreases in the norepinephrine concentrations. In contrast, ejection fraction did not change in any group. Mild hypothermia during combined epidural anesthesia and general anesthesia markedly reduced cardiac output in dogs, mainly by decreasing heart rate.

Factors affecting resistance to induced body cooling in newborn lambs of 10 breeds

ABSTRACT1. The ability to resist hypothermia was measured in 265 lambs of 10 breeds immersed in a progressively cooling water bath.2. Cold resistance varied significantly between breeds, with hill lambs showing the highest resistance. Hill breeds and feral breeds together had the highest weight-specific cold resistance.3. Cold resistance was positively correlated with birth weight and skinfold thickness.4. Age at test varying from 1 to 60 h did not significantly affect cold resistance.5. Rate of recovery from hypothermia varied slightly between breeds. The feral lambs tended to recover fastest.

Increased serotonin level via augmented tryptophan diet and its effect on escape learning.

Brain serotonin level was increased by supplementing the diet in two groups of rats. They were first exposed to conditions of shock, either escapable or inescapable. They were then placed in a cool water bath, and the response latency to successful escape was noted. Two other groups fed normal diets were similarly examined. Tryptophan effects of hypothermia were shown to interact with the analgesic effects of serotonin and to the tolerance of the noxious water bath. The results are discussed in relation to brain serotonin effects on escape following shock pretreatment ("learned helplessness") and its relevance to clinical depression.

Hypothermia in newborn lambs induced by experimental immersion in a water bath and by natural exposure outdoors

A progressively cooling water bath technique was developed to measure resistance to body cooling in newborn lambs. Cold resistance, defined as the time taken to reduce rectal temperature to 35 degrees C, was measured in 429 lambs of 12 different breeds individually immersed in a water bath. Two alternative procedures were used with water temperature falling from 37 degrees C to 12 degrees C or from 25 degrees C to 10 degrees C. In lambs tested twice the repeatability of cold resistance was high: 0.95 and 0.81 respectively in the two types of test. There were clear breed differences in cold resistance, some breeds being up to three times more resistant than others. Health was unimpaired by treatment and preweaning mortality was not affected. Ten of the breeds represented in water bath tests were also used for measurements of rectal temperature 1 h after birth in the field. There was some similarity in the breed rank order for ability to resist hypothermia in the field and in the water bath. Water bath tests of hypothermia in lambs could facilitate genetic selection for improved perinatal survival in the field.