Cold Vasodilatation of the Rat Tail

1975 ◽  
Vol 53 (2) ◽  
pp. 207-210 ◽  
Author(s):  
B. Hellström
Keyword(s):  
Skin Temperature ◽  
Temperature Increase ◽  
Onset Time ◽  
Albino Rats ◽  
Peak Time ◽  
Ambient Temperatures ◽  
Air Temperatures ◽  
Ice Water ◽  
Rat Tail

The tail-skin temperature was measured in nine male albino rats resting at chamber air temperatures between 40 and 16 °C. Spontaneous increases of tail temperature, strongly indicative of cold-induced vasodilatations (CIVD), were evoked by immersing the tail in ice water. The reproducibility of onset time and peak time of the CIVD was best for the first wave of temperature increase. Tail temperatures prior to immersion indicated vasodilatation when the rat rested at chamber temperatures of 28 °C or above, vasoconstriction when the chamber was kept at 24 °C or lower. The number of rats showing CIVD decreased with decreasing ambient temperatures below 32 °C.

Extremity skin temperature in British and Zebu cross cattle

1967 ◽  
Vol 69 (1) ◽  
pp. 1-7 ◽  
Author(s):  
K. G. Johnson ◽  
M. E. D. Webster
Keyword(s):  
Skin Temperature ◽  
Lower Leg ◽  
Zebu Cattle ◽  
Temperature Changes ◽  
Ambient Temperatures ◽  
Thermal Environments ◽  
Air Temperatures ◽  
Environmental Temperatures ◽  
Skin Temperatures ◽  
Trunk Skin

1. Extremity skin temperature changes in British and Zebu cross cattle examined in moderate thermal environments followed a thermoregulatory pattern similar to that describedby Whittow (1962). At low environmental temperatures, ear and lower leg skin temperatures were usually only slightly above air temperature. At a variable time after air temperatures began to rise or the animals were fed, extremity skin temperatures increased suddenly to near trunk skin temperature.2. In eight of the ten pairs of animals studied in rising ambient temperatures and during feeding after fasting for 36–72 hr, increases in ear temperature were measured in the British animal before similar changes occurred in its Zebu counterpart. Changes in lower leg skin temperature followed a similar pattern.Trunk skin temperatures and respiratory frequencies were significant higher in British cross animals than in Zebu cross animals of similar thermal history. The mean rectal temperature of both British and Zebu cattle was 38·5 °C.

Thermoregulation in Exercising White Rats

1973 ◽  
Vol 51 (11) ◽  
pp. 814-824 ◽  
Author(s):  
K. Myhre ◽  
B. Hellstrøm
Keyword(s):  
Thermal Stress ◽  
Skin Temperature ◽  
Albino Rats ◽  
Cold Environment ◽  
Exercise Time ◽  
Ambient Temperatures ◽  
Warm Environment ◽  
White Rats ◽  
Skin Temperatures ◽  
Trunk Skin

Colonic temperatures (TC), heart rates (HR), back skin and tail skin temperatures (TST) were measured in six warm acclimated (+24 °C) male albino rats running on a treadmill at three different work loads (HR ranging from 400 beats/min to 500 beats/min). Ambient temperatures (TA) ranged from about +8 °C to about +30 °C. TC increased immediately upon onset of work. Exercising in a cold environment ultimately made the rats hypothermic and in a warm environment hyperthermic. Within the limits set by the external thermal stress the rats controlled TC independently of the work intensity.High trunk skin temperatures were recorded in all experiments. Exercise in cold and cool environments produced tail skin vasoconstriction. In the 21 °C environment half of the rats produced tail skin vasodilation. In the 28 °C environment most experiments produced this effect. Cessation of work was accompanied by prompt vasoconstriction. The results indicated that exercise time before tail vasodilation was affected by exercise as well as by the tail skin temperature prior to vasodilation.

scholarly journals Performance Evaluation of a CO2 Refrigeration System Enhanced with a Dew Point Cooler

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1079 ◽  
Author(s):  
Martin Belusko ◽  
Raymond Liddle ◽  
Alemu Alemu ◽  
Edward Halawa ◽  
Frank Bruno
Keyword(s):  
Weather Conditions ◽  
Dew Point ◽  
Coefficient Of Performance ◽  
Experimental Program ◽  
Refrigeration System ◽  
Conventional System ◽  
Ambient Temperatures ◽  
Air Temperatures ◽  
Condenser Temperature

Dew point cooling (DPC) is a novel indirect evaporative cooling concept capable of delivering air temperatures approaching the dew point. Coupling this technology with CO2 refrigeration is well suited to minimising transcritical operation when the coefficient of performance (COP) is dramatically reduced in hot climates. A substantial experimental program was conducted to characterise this combination by testing a 20 kW CO2 refrigeration system subject to ambient temperatures above 40 °C. It was demonstrated that DPC operation not only avoided transcritical operation during such weather conditions, but also increased the COP by up to 140% compared to the conventional system. The combination of these technologies was successfully mathematically modelled, from which the optimum condenser inlet air temperature was identified for each condenser temperature. Using this optimum condition, it was possible to maximise the COP for a range of conditions applicable to the psychometric chart. An annual case study for Adelaide, Australia was conducted which demonstrated that optimally coupling DPC with CO2 refrigeration can reduce the annual energy consumption and peak demand by 16% and 47%, respectively, compared to a conventional CO2 booster system. Furthermore, the number of hours of transcritical operation was reduced from 3278 to 27.

CALCULATED DETERMINATION OF PRE-HEATING PARAMETERS FOR WELDING POLYETHYLENE PIPES FOR GAS PIPELINES AT LOW AIR TEMPERATURES.

2021 ◽  
pp. 29-31
Author(s):  
I. Tarabukin
Keyword(s):  
Low Temperatures ◽  
Weld Seam ◽  
Gas Pipelines ◽  
Ambient Temperatures ◽  
Regulatory Documents ◽  
Polyethylene Pipes ◽  
Heated Air ◽  
Air Temperatures ◽  
Different Characteristics

According to regulatory documents, welding can be performed at ambient temperatures from minus 15 ° C to plus 45 ° C. When laying gas pipelines at a lower outside temperature, it is necessary to organize their heating to the required temperature. In this case, the temperature of the heated air should not be more than plus 60 ° C. If you start working with a polyethylene (PE) pipe at low temperatures, then the PE pipe will have completely different characteristics. The weld seam may not be reliable.

Spaceflight on STS-48 and earth-based unweighting produce similar effects on skeletal muscle of young rats

1993 ◽  
Vol 74 (5) ◽  
pp. 2161-2165 ◽  
Author(s):  
M. E. Tischler ◽  
E. J. Henriksen ◽  
K. A. Munoz ◽  
C. S. Stump ◽  
C. R. Woodman ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Extensor Digitorum Longus ◽  
Space Shuttle ◽  
Weight Bearing ◽  
Similar Rate ◽  
Extensor Digitorum ◽  
Hindlimb Suspension ◽  
Albino Rats ◽  
Sprague Dawley ◽  
Ambient Temperatures

Our knowledge of the effects of unweighting on skeletal muscle of juvenile rapidly growing rats has been obtained entirely by using hindlimb-suspension models. No spaceflight data on juvenile animals are available to validate these models of simulated weightlessness. Therefore, eight 26-day-old female Sprague-Dawley albino rats were exposed to 5.4 days of weightlessness aboard the space shuttle Discovery (mission STS-48, September 1991). An asynchronous ground control experiment mimicked the flight cage condition, ambient shuttle temperatures, and mission duration for a second group of rats. A third group of animals underwent hindlimb suspension for 5.4 days at ambient temperatures. Although all groups consumed food at a similar rate, flight animals gained a greater percentage of body mass per day (P < 0.05). Mass and protein data showed weight-bearing hindlimb muscles were most affected, with atrophy of the soleus and reduced growth of the plantaris and gastrocnemius in both the flight and suspended animals. In contrast, the non-weight-bearing extensor digitorum longus and tibialis anterior muscles grew normally. Earlier suspension studies showed that the soleus develops an increased sensitivity to insulin during unweighting atrophy, particularly for the uptake of 2-[1,2–3H]deoxyglucose. Therefore, this characteristic was studied in isolated muscles within 2 h after cessation of spaceflight or suspension. Insulin increased uptake 2.5- and 2.7-fold in soleus of flight and suspended animals, respectively, whereas it increased only 1.6-fold in control animals. In contrast, the effect of insulin was similar among the three groups for the extensor digitorum longus, which provides a control for potential systemic differences in the animals.

scholarly journals Subtropical mouse-tailed bats use geothermally heated caves for winter hibernation

2015 ◽  
Vol 282 (1804) ◽  
pp. 20142781 ◽  
Author(s):  
Eran Levin ◽  
Brit Plotnik ◽  
Eran Amichai ◽  
Luzie J. Braulke ◽  
Shmulik Landau ◽  
...  
Keyword(s):  
High Temperature ◽  
Skin Temperature ◽  
Metabolic Rates ◽  
Evaporative Water ◽  
Open Flow ◽  
Ambient Temperatures ◽  
Northern Edge ◽  
Average Skin ◽  
World Distribution ◽  
Winter Hibernation

We report that two species of mouse-tailed bats ( Rhinopoma microphyllum and R. cystops ) hibernate for five months during winter in geothermally heated caves with stable high temperature (20°C). While hibernating, these bats do not feed or drink, even on warm nights when other bat species are active. We used thermo-sensitive transmitters to measure the bats’ skin temperature in the natural hibernacula and open flow respirometry to measure torpid metabolic rate at different ambient temperatures ( T a , 16–35°C) and evaporative water loss (EWL) in the laboratory. Bats average skin temperature at the natural hibernacula was 21.7 ± 0.8°C, and no arousals were recorded. Both species reached the lowest metabolic rates around natural hibernacula temperatures (20°C, average of 0.14 ± 0.01 and 0.16 ± 0.04 ml O 2 g −1 h −1 for R. microphyllum and R. cystops , respectively) and aroused from torpor when T a fell below 16°C. During torpor the bats performed long apnoeas (14 ± 1.6 and 16 ± 1.5 min, respectively) and had a very low EWL. We hypothesize that the particular diet of these bats is an adaptation to hibernation at high temperatures and that caves featuring high temperature and humidity during winter enable these species to survive this season on the northern edge of their world distribution.

Roasted Barley Extract Affects Blood Flow in the Rat Tail and Increases Cutaneous Blood Flow and Skin Temperature in Humans

2018 ◽  
Vol 66 (5) ◽  
pp. 1251-1257 ◽  
Author(s):  
Hiroshi Ashigai ◽  
Yoshimasa Taniguchi ◽  
Yasuko Matsukura ◽  
Emiko Ikeshima ◽  
Keiko Nakashima ◽  
...  
Keyword(s):  
Blood Flow ◽  
Skin Temperature ◽  
Cutaneous Blood Flow ◽  
Cutaneous Blood ◽  
Rat Tail

Rat tail skin temperature regulation by estrogen, phytoestrogens and tamoxifen

Maturitas ◽  
2004 ◽  
Vol 48 (4) ◽  
pp. 463-471 ◽  
Author(s):  
Evan E Opas ◽  
Su Jane Rutledge ◽  
Robert L Vogel ◽  
Gideon A Rodan ◽  
Azriel Schmidt
Keyword(s):  
Skin Temperature ◽  
Temperature Regulation ◽  
Rat Tail

Studies on the adaptability of three breeds of sheep to a tropical environment modified by altitude II. Responses in body, skin and coat temperatures, cardio-respiratory frequencies and rate of moisture secretion of ewes to the diurnal fluctuation in ambient temperature during the hottest part of the year

1960 ◽  
Vol 55 (3) ◽  
pp. 295-302 ◽  
Author(s):  
R. B. Symington
Keyword(s):  
Body Temperature ◽  
Ambient Temperature ◽  
Skin Temperature ◽  
Skin Surface ◽  
Diurnal Fluctuation ◽  
Body Temperatures ◽  
Solar Insolation ◽  
Air Temperatures ◽  
Insensible Perspiration ◽  
Artificial Heat

Responses in body, skin and coat temperatures, cardio-respiratory frequencies and rate of moisture secretion of ewes of three breeds to the diurnal fluctuation in ambient temperature were recorded in the presence and absence of drinking water during the hottest part of the Rhodesian year.1. At 7.0 a.m. body temperatures were: Merino 102·8° F.; Persian 102·2° F. and Native 101·5° F. Between 7·0 a.m. and 1·0 p.m. body temperature rose almost equally in Persians and Natives and fell slightly in Merinos. Change in body temperature between 7.0 a.m. and 1.0 p.m. was not affected significantly by availability of water nor age of ewe, but varied with type of thermal burden (i.e. solar insolation only v. solar insolation plus artificial heat) when water was not available. Although air temperature fell towards late afternoon body temperature of Merinos and Natives rose appreciably, that of Persians only slightly.2. At 7·0 a.m. respiratory rates were (cyc./min.): Merino 59·6; Persian 43·0; Native 29·9. Increase in rate of respiration was the main thermolytic mechanism in all breeds. Merinos had a lower threshold of respiratory response to rising ambient temperature than either hair breed but increase in rate of respiration between 7.0 a.m. and 1.0 p.m. did not differ significantly with breed or age.3. No breed appeared to use the peripheral blood system in thermoregulation. Cardio-frequency, as a measure of this blood flow, remained almost constant with a slight tendency to fall with rise in ambient temperature.4. In all breeds skin temperature was related to ambient and body temperatures; consequently the diurnal fluctuation in skin temperature differed in wool and hair breeds. When thermal burden was greatest Merino skin temperature fell, that of hair breeds did not.Except at 11.0 a.m. there was a gradient between rectal, skin and air temperatures. Direct elimination of heat was thus possible for 23 hr. each day.5. In hair breeds moisture secretion depended on insensible perspiration; consequently, rate of moisture secretion changed with body and air temperatures. In Merinos moisture for skin surface evaporation was provided by sensible and insensible perspiration. Natives may be able to sweat at temperatures higher than those recorded but it is unlikely Persians have a sweating mechanism.6. In all breeds coat temperature was related closely to ambient temperature and changes in solar conditions evoked immediate response in coat temperature. Merino fleece apparently stabilized skin temperature whereas Persian and Native hair did not.

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