Effect Of Radiant Heat Research Articles

The Effect of Sub-MAC Anesthesia and the Radiation Setting on Repeated Tail Flick Testing in Rats

The tail flick (TF) response is regarded as a spinal reflex that is influenced by supraspinal structures. The TF test using radiant heat is the most common way to assess pain perception; however, there are few reports dealing with the heat source's properties and score consistency. This study examined the usefulness of light anesthesia for suppressing supraspinal signals and the effects of radiant heat on skin temperature during TF testing. The fluctuations of TF latency over one hour were evaluated while the rats were given oxygen and 0%, 0.5%, 1.0%, or 1.5% isoflurane. The stimulator's infrared radiant (IR) power flux was measured over time, and the tail skin surface temperature was predicted using a non-linear regression equation. TF latencies were measured at various heat source intensities, and response temperatures were estimated. Inhalation anesthesia suppressed the TF reflex according to the inspiratory concentration of the volatile anesthetic. IR power fluxes reached constant power 2.5 s after the stimulator was turned on, and the predicted skin temperature depended on the maximum IR power flux of the IR intensity and the radiation time. One percent isoflurane inhalation and an IR20 heat intensity (which was 161.5 mW/cm(2) and resulted in a skin temperature of 65 degrees C after 10 s of radiation) provided reliable TF latencies on repeated TF testing. Given these results, it can be concluded that the stimulator setting influenced TF latency, and that the inhalation of light anesthesia provided consistent scores on repeated TF testing.

Seed bank response to wet heat and the vegetation structure of a Virginia pocosin1

Pocosins are shrub wetlands of the southeastern coastal plain maintained by fire. Increased herbaceous plant diversity has been reported after wildfire. To test the effect of radiant heating on the seed bank of pocosin-upland ecotones, wet heat treatments were applied to Sphagnum substrate from a Virginia small depression pocosin. The seedling emergence method was used to quantify wetland seedling abundance and richness. Extant vegetation was measured at each seed bank sampling area and the seed bank and vegetation were compared with Sorenson similarity values. No significant seedling abundance, richness, or evenness effects were detected among wet heat and control groups. However, the high wet heat treatment (75 °C) significantly reduced the density of Sphagnum cuspidatum capitula more than 80% relative to the control. Mean seed bank density was 6,209 seedlings/m2 (richness = 11) and was dominated by Scirpus cyperinus (97.8%), contained many early successional species. The seed bank did not closely resemble the extant vegetation. Pocosin canopy was sparse and dominated by Pinus serotina. The shrub-sapling stratum indicated co-dominance of Acer rubrum and ericaceous species, potentially indicating a shift from a shrub bog to a wet pine-hardwood community.

Radiant heat affects thermoregulation and energy expenditure during rewarming from torpor.

The high expenditure of energy required for endogenous rewarming is one of the widely perceived disadvantages of torpor. However, recent evidence demonstrates that passive rewarming either by the increase of ambient temperature or by basking in the sun appears to be common in heterothermic birds and mammals. As it is presently unknown how radiant heat affects energy expenditure during rewarming from torpor and little is known about how it affects normothermic thermoregulation, we quantified the effects of radiant heat on body temperature and metabolic rate of the small (body mass 25 g) marsupial Sminthopsis macroura in the laboratory. Normothermic resting individuals exposed to radiant heat were able to maintain metabolic rates near basal levels (at 0.91 ml O(2) g(-1) h(-1)) and a constant body temperature down to an ambient temperature of 12 degrees C. In contrast, metabolic rates of individuals without access to radiant heat were 4.5-times higher at an ambient temperature of 12 degrees C and body temperature fell with ambient temperature. During radiant heat-assisted passive rewarming from torpor, animals did not employ shivering but appeared to maximise uptake of radiant heat. Their metabolic rate increased only 3.2-times with a 15- degrees C rise of body temperature (Q(10)=2.2), as predicted by Q(10) effects. In contrast, during active rewarming shivering was intensive and metabolic rates showed an 11.6-times increase. Although body temperature showed a similar absolute change between the beginning and the end of the rewarming process, the overall energetic cost during active rewarming was 6.3-times greater than that during passive, radiant heat-assisted rewarming. Our study demonstrates that energetic models assuming active rewarming from torpor at low ambient temperatures can substantially over-estimate energetic costs. The low energy expenditure during passive arousal provides an alternative explanation as to why daily torpor is common in sunny regions and suggests that the prevalence of torpor in low latitudes may have been under-estimated in the past.

Treatments for breast engorgement during lactation.

National surveys have shown that painful breasts are the second most common reason for giving up breastfeeding in the first two weeks after birth in the UK. One factor contributing to such pain can be breast engorgement. Views differ as to how engorgement arises, although restrictive feeding patterns in hospital are likely to have contributed in the past. These differing views are reflected in the range of solutions offered to treat engorgement in breastfeeding mothers and these treatments are assessed in this review. To determine the effects of any proposed intervention to relieve symptoms of breast engorgement among breastfeeding women. The register of clinical trials maintained and updated by the Cochrane Pregnancy and Childbirth Group. CINAHL and MEDLINE were also searched. Date of last search: December 2000. All randomised and 'quasi-randomised' controlled trials, with or without blinding, that assess the effectiveness of treatments for the alleviation of symptoms in breastfeeding women experiencing engorgement. Data were extracted by one reviewer and verified by a second reviewer. Eight trials, involving 424 women, were included. Three different studies were identified which used cabbage leaves or cabbage leaf extracts;. no overall benefit was found. Ultrasound treatment and placebo were equally effective. Use of Danzen (an anti-inflammatory agent) significantly improved the total symptoms of engorgement when compared to placebo (odds ratio (OR) 3.6, 95% confidence interval (CI) 1.3 - 10.3) as did bromelain/trypsin complex (OR 8.02, 95% CI 2.8-23.3). Oxytocin and cold packs had no demonstrable effect on engorgement symptoms. Cabbage leaves and gel packs were equally effective in the treatment of engorgement. Since both cabbage extract and placebo cream were equally effective, the alleviation in symptoms may be brought about by other factors, such as breast massage. Ultrasound treatment is equally effective with or without the ultra-wave emitting crystal, therefore its effectiveness is more likely to be due to the effect of radiant heat or massage. Pharmacologically, oxytocin was not an effective engorgement treatment while Danzen and bromelain/trypsin complex significantly improved the symptoms of engorgement. Initial prevention of breast engorgement should remain the key priority.

WITHDRAWN: Treatments for breast engorgement during lactation.

National surveys have shown that painful breasts are the second most common reason for giving up breastfeeding in the first two weeks after birth in the UK. One factor contributing to such pain can be breast engorgement. Views differ as to how engorgement arises, although restrictive feeding patterns in hospital are likely to have contributed in the past. These differing views are reflected in the range of solutions offered to treat engorgement in breastfeeding mothers and these treatments are assessed in this review. To determine the effects of any proposed intervention to relieve symptoms of breast engorgement among breastfeeding women. The register of clinical trials maintained and updated by the Cochrane Pregnancy and Childbirth Group. CINAHL and MEDLINE were also searched. Date of last search: December 2000. All randomised and 'quasi-randomised' controlled trials, with or without blinding, that assess the effectiveness of treatments for the alleviation of symptoms in breastfeeding women experiencing engorgement . Data were extracted by one reviewer and verified by a second reviewer. Eight trials, involving 424 women, were included. Three different studies were identified which used cabbage leaves or cabbage leaf extracts;. no overall benefit was found. Ultrasound treatment and placebo were equally effective. Use of Danzen (an anti-inflammatory agent) significantly improved the total symptoms of engorgement when compared to placebo (odds ratio (OR) 3.6, 95% confidence interval (CI) 1.3 - 10.3) as did bromelain/trypsin complex (OR 8.02, 95% CI 2.8-23.3). Oxytocin and cold packs had no demonstrable effect on engorgement symptoms. Cabbage leaves and gel packs were equally effective in the treatment of engorgement. Since both cabbage extract and placebo cream were equally effective, the alleviation in symptoms may be brought about by other factors, such as breast massage. Ultrasound treatment is equally effective with or without the ultra-wave emitting crystal, therefore its effectiveness is more likely to be due to the effect of radiant heat or massage. Pharmacologically, oxytocin was not an effective engorgement treatment while Danzen and bromelain/trypsin complex significantly improved the symptoms of engorgement. Initial prevention of breast engorgement should remain the key priority.

Effect of radiant heat on head temperature gradient in term infants.

To test the hypothesis that external radiant heating might lead to significant fluctuations in superficial and core head temperatures in newborn infants. In an observation group of 14 term infants nursed under a radiant heater, servo-controlled to the abdominal skin, changes in rectal, core head, and scalp temperatures with heater activation were examined. In a further intervention group of six infants the effect of a reflective head shield on the fluctuations of scalp temperature was also tested. In the observation group, when the heater had been off for 30 minutes, the rectal and scalp temperatures were 36.7 (SD 0.6) and 35.6 (0.6) degrees C, respectively, a difference of 1.2 (0.2) degrees C. After 30 minutes with the radiant heater on this fell to 0.2 (0.5) degrees C. The core head temperature, however, remained similar to the rectal temperature throughout. In the intervention group a reflective shield prevented the loss of the rectal-scalp gradient. Overhead heater activation is associated with loss of the core to scalp temperature gradient, but no change in core head temperature in term infants. The clinical relevance of this superficial heating in vulnerable infants warrants further study.

Effect of radiant heat on the surface hardness of glass polyalkenoate (ionomer) cement

The use of heat to improve mechanical properties of materials is a widely accepted phenomenon. It has been studied in dentistry with a view to improving the properties of resin composite. Dental cements may benefit by the application of heat, in particular with regard to their early surface properties. This study was carried out to examine the effect of the application of radiant heat to the surface hardness of one type of glass polyalkenoate cement. It was found that raising the temperature of the surface of the cement to a maximum of 60°C significantly improved the early surface hardness of the material. The application of a high level of heat also improved the surface hardness of the cement after 24 h compared to cement which had not been heat treated. The use of heat would appear to accelerate the matrix-forming reaction of the material and although further work is necessary this technique may have clinical application.

Bench‐scale evaluations and mechanistic studies of intumescent/fire‐protective coatings for polyvinyl chloride nitrile rubber

AbstractThe object of this study was to identify, for future large‐scale testing, and adequate fire‐protective coating for the substrate, polyvinyl chloride (PVC) nitrile rubber (MIL‐P‐15280 Rev H). Fifteen fire protective coatings which included ten intumescent, two ablatives, two fire retardants and one photon diffusive coatings were evaluated using bench‐scale thermal insults. To discern the possible mechanism(s) whereby the coatings offer fire protection, the effect of radiant heat versus the flame source employed was investigated and thermogravimetric analysis (TGA) of the neat coatings was performed. In selected cases, the effect of coating thickness and repeatability of the results were evaluated. The differences in coating effectiveness, and the varied repeatability in three of the four cases examined, focus on the inherent complexity of intumescence, as well as on the importance of scaled‐up testing of coatings that appeared promising. Thermogravimetric analyses of the coatings indicate that two selected TGA measurements/parameters, when used in conjunction, appear useful in characterizing mechanistic differences between the less effective and more effective coatings. Based on the rigorous criterion adopted, one candidate (a water‐based intumescent coating at 100 mil (2.54 mm) thickness) appears promising for the substrate, PVC nitrile rubber. Its effectiveness is attributable to it exhibiting good insulative and re‐radiative properties and an apparent low susceptibility to crack formation.

Effects of Radiant heat and Meperidine on Oxygen Consumption in Postanesthesia Shivering

Effects of Radiant heat and Meperidine on Oxygen Consumption in Postanesthesia Shivering

Should Wet-Bulb Thermometers be Shielded when Measuring Heat Stress?

An experiment was performed in order to investigate the effect of radiant heat on wet bulb temperature measurement. It was found that the radiant heat affect the natural wet bulb temperature and this effect becomes larger as the radiant heat level becomes higher and air velocity becomes lower. This radiant heat and air velocity effect on natural wet bulb temperature is quantified. Also, a set of relationship between unshielded and shielded natural wet bulb temperatures under various radiant heat and air velocity was found.

Effects of Radiant Heat upon the Thermal Load of a Heated Room : Part 3-Existence of Energy Savings Border in the Space

Effects of Radiant Heat upon the Thermal Load of a Heated Room : Part 3-Existence of Energy Savings Border in the Space

Effects of Radiant Heat upon the Thermal Load of a Heated Room : Part 2-A Statistical Analysis of Results of Numerical Experiments about the Heat Loss from a Heated Room as well as Introduction of a New Simplified Method for Calculation of Room Thermal Load

Effects of Radiant Heat upon the Thermal Load of a Heated Room : Part 2-A Statistical Analysis of Results of Numerical Experiments about the Heat Loss from a Heated Room as well as Introduction of a New Simplified Method for Calculation of Room Thermal Load

Effects of radiant heat in fire fighting instructors.

Effects of radiant heat in fire fighting instructors.

Effects of Radiant Heat upon the Thermal Load of a Heated Room : Part 1-A Theoretical Study on the Critical Convection Heat Transfer Coefficient

Effects of Radiant Heat upon the Thermal Load of a Heated Room : Part 1-A Theoretical Study on the Critical Convection Heat Transfer Coefficient

Fire Fighters' SCBA Belt Radiant Heat Resistance

An investigation of the effects of radiant heat on the belts of self-contained breathing apparatus commonly used by fire fighters shows the need for standards to establish test methods and performance criteria for SCBA resistance to radiant heat.

Some Effects of 8–12 µm Radiant Energy Transfer on the Mass and Heat Budgets of Cloud Droplets

In standard treatments of the mass and energy budget of cloud droplets, radiant energy transfer is neglected on the grounds that the temperature difference between the droplet and its surroundings is small. This paper includes the effect of radiant heating and cooling of droplets by using the Eddington approximation for the solution of the radiative transfer equation. Although the calculation assumes that the cloud is isothermal and has a constant size spectrum with altitude, the heating or cooling of droplets by radiation changes the growth rate of the droplets very significantly. At the top of a cloud with a base at 2500 m and a top at 3000 m, a droplet will grow from 9.5 to 10.5 microns in about 4 min, assuming a supersaturation ratio of 1.0013. Such a growth rate is more than 20 times the growth rate for condensation alone, and may be expected to have a significant impact on estimates of precipitation formation as well as on droplet spectrum calculations.

Effects of Radiant Heat on Market-Size Broiler Chicks Grown in a Cyclic High Temperature Environment

PREVIOUS studies showed that broiler chicks grown in a high temperature environment during the latter part of the production period had poorer growth rates and feed conversion than those grown in a more moderate temperature (Winn and Godfrey, 1967; Huston, 1965; Adams et al., 1962; Joiner and Huston, 1957). Chicks grown in the open-wall, noninsulated-roof houses in some areas of the U. S. are not only subjected to high temperature and in some instances high temperature and humidity environments, but also to an additional radiant heat load from the hot roof, walls and surroundings. Few, if any, data are available to show what effects the radiant heat load during the period of high temperature and/or humidity have on the performance of broiler chicks which are near market size. Authors observed in previous studies that chick mortality was higher on hot, sunny days in a noninsulated-roof house than in an insulated-roof…

Electrical space conditioning in the USA

'Electrical space conditioning' expresses the need to consider control of all factors influenced by modern building lighting. When the criteria of good lighting design are established, attention can be turned to controlling and using the heat generated by lighting. Examples show that modern lighting installations introduce sufficient energy to largely counterbalance building energy losses in cold weather. In warm weather the energy introduced from the lighting, together with heat gains from people, machines and sun, must be controlled. Returning air through luminaires not only brings thermal gains under control but does much to offset radiant heating effects. Typical installations using electrical space conditioning principles are analysed and the range of systems that can be usad is indicated.

Reply to Professor Macpherson's critique

We are grateful to Professor Macpheron for his critique of our paper and particularly for his constructive criticism of our comments on the weighting given in the P4SR index to the effects of mean radiant temperature (M.R.T.). However, before we deal in detail with Professor Macpherson's critique it is necessary to put into perspective the various aspects of our study because, in Professor Macpherson's opinion, one of our comments on the effects of radiation 'represents the major scientific finding described in the paper'. This is certainly not our view. We feel that because of the undue emphasis Professor Macpherson gives in his critique to this aspect of the paper he has lost sight of the main purposes of the study. There were two main aims of the study in the mine at Mount Isa. The first was to determine which of three methods of assessing heat stress, the W.B., the C.E.T., or the P4SR, predicts most accurately the heat stress in the mine. The second aim was to try to set limits, based upon a rational physiological criterion, of heat stress at which the shift should be curtailed and at which work should be stopped. Professor Macpherson criticizes our attempt to achieve these aims by carrying out a study in the mine. We recognize his preference for hot room studies but the purposes for which the indices of heat stress were introduced was to be able to assess heat stress in industry. Academic exercises in hot rooms have their place but, finally, the accuracy of the indices of heat stress must be examined in industry if they are to be of any practical use. When we plotted oral temperatures against P4SRs we found that the plots for high G.T.s fell well below the rest of the data. This result was quite unexpected but we regard it as an incidental finding. It does, however, raise some important issues with regard to the weighting given by P4SR to the effects of radiant heat and we would have been wrong to have ignored these issues. Professor Macpherson advances two criticisms of our interpretation of the anomalous finding with regard to oral temperatures at high G.T.s. In the first he disagrees with our division of the oral temperature/P4SR data into two class-intervals of differences between D.B. and G.T. This is a common statistical practice and we used a similar approach in examining the accuracy with which P4SR takes account of differences between D.B. and W.B. In his second criticism Professor Macpherson expresses surprise that the mathematical analysis of the relative weighting given to various heat stress parameters by P4SR shows that the effect of increasing D.B. decreases P4SR. A moment's reflection will enable the reader to appreciate that the net effect of an increase in D.B., with all other environmental measurements held constant, would be a lowering of the relative humidity, and, in the range of air conditions examined, this would have the effect of reducing the heat stress as expressed by P4SR. Dealing with our comments on the effect of M.R.T. on P4SR, Professor Macpherson complains that we misquoted Ferres et al. (1954) by inserting in brackets the words 'as measured by G.T.' It would have been better if these words had appeared in italics to indicate that they were inserted by us and if anyone has been misled we apologize. We merely wished to draw attention to the fact that M.R.T. was determined from measurements of G.T., using Bedford's equation, and not by any other method such as a radiometer, for example. Professor Macpherson points out an error in our comments on the conclusion of Ferres et al. and we are grateful to him for doing so. The statement at the top of page 264 should be changed to read :

On the surface temperature of substrates on a hotplate used for epitaxial growth

With the help of thin-film Au-constantan thermocouples the surface temperature of mica substrates on a hotplate was measured. The improvement of the thermal contact between the substrate and the hotplate by a thin layer of aquadag was verified and the influence of the mica thickness on its surface temperature was evaluated. The thin-film thermocouple proved useful for the investigation of the effect of radiant heat from the evaporation source on the temperature of the substrate surface.