EFFETS DE L'ACIDE ASCORBIQUE SUR PLUSIEURS VARIABLES BIOLOGIQUES NORMALEMENT AFFECTÉES PAR LE FROID

1949 ◽  
Vol 27e (6) ◽  
pp. 349-363 ◽  
Author(s):  
M. Thérien ◽  
J. Leblanc ◽  
O. Héroux ◽  
L. P. Dugal
Keyword(s):  
Blood Pressure ◽  
Ascorbic Acid ◽  
Room Temperature ◽  
Experimental Studies ◽  
The Other ◽  
Histamine Content ◽  
Exposure To Cold ◽  
Thymus Atrophy ◽  
Subsequent Administration ◽  
Made In

It has been shown recently by Dugal and Thérien that during a short or long exposure to cold, the normal hypertrophy of the adrenals is completely prevented by large doses of ascorbic acid, and that, nevertheless, at the same time, resistance is increased towards the same damaging agent. So, the most universally accepted criterion of damage caused by stress is abolished when the animals exposed to cold receive large doses of ascorbic acid. Starting from that observation, it was natural to wonder what would be the effects of the ascorbic acid on the biological changes normally associated with the hypertrophy of the adrenals during exposure to cold. The present paper describes the experimental studies made in that connection; the results obtained show that: (1) ascorbic acid (a) partly inhibits the thymus atrophy normally encountered upon exposure to any stress including cold, (b) accelerates in a very significant way the enlargement of the thyroid, (c) is responsible for an increase in weight of the spleen, whereas the control animals, on the contrary, show a decrease in weight of the same organ; (2) the histamine content of the adrenals, which increases at room temperature under the influence of ascorbic acid, is significantly decreased during exposure to cold under the influence of the same substance; (3) the activity of the adrenals, far from being inhibited by ascorbic acid is even increased if the cholesterol changes are taken as an index of that activity; (4) the initial hypotension—due to cold—found in our controls, is prevented by large doses of ascorbic acid; on the other hand, if hypertension develops after long exposure to cold, the subsequent administration of large doses of ascorbic acid restores the blood pressure to normal. Confirmation has also been obtained for the previously reported observation that ascorbic acid prevents the hypertrophy of the adrenals during exposure to cold.

scholarly journals Effort investment in uncontrollable situations: The moderating role of motivation toward closure

2021 ◽  
Vol 45 (2) ◽  
pp. 186-196
Author(s):  
Paulina Szwed ◽  
Małgorzata Kossowska ◽  
Marcin Bukowski
Keyword(s):  
Blood Pressure ◽  
Experimental Studies ◽  
The Other ◽  
Need For Closure ◽  
Extra Effort ◽  
Moderating Role ◽  
Energy Conservation Principle ◽  
Principle Of Energy Conservation ◽  
Investment Behaviour

AbstractAccording to the principle of energy-conservation principle, effort investment is usually reduced in situations that are perceived as uncontrollable. This is because when success is recognized as impossible, any effortful actions are no longer justified. However, we predicted that individual differences in uncertainty tolerance, i.e., the need for closure (NFC), may moderate effort investment in uncontrollable situations. We tested this prediction in two experimental studies in which we exposed participants with differing levels of NFC to uncontrollable events, and indexed effort through the assessment of systolic blood pressure (SBP) responses. As predicted, in the uncontrollability (vs. controllability) condition, effort investment decreased significantly among low- but not high-NFC participants. Since gaining certainty and achieving closure is not a critical epistemic goal for low-NFC individuals, exerting extra effort to gain certainty is therefore no longer justified. On the other hand, high-NFC participants do not withhold their efforts, as they are highly motivated to obtain certainty. These results may help to account for contradictory findings in effort-investment behaviour and add substantively to the literature concerning motivation toward closure.

scholarly journals FLUORESCEIN CIRCULATION TIME AS A PROGNOSTIC SIGN IN EXPERIMENTAL TRAUMATIC SHOCK

1946 ◽  
Vol 84 (6) ◽  
pp. 549-558 ◽  
Author(s):  
S. C. Wang ◽  
E. E. Painter ◽  
R. R. Overman
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Vascular System ◽  
Peripheral Circulation ◽  
Traumatic Shock ◽  
Systemic Circulation ◽  
The Other ◽  
Circulation Time ◽  
Peripheral Vascular ◽  
Made In

Repeated determinations of the circulation time by the fluorescein method were made in normal and shocked dogs. In normal animals the circulation time ranges from 9 to 16 seconds with an average of 12.6 seconds. In traumatic shock the circulation time is invariably prolonged. For prognosis in the traumatized animal two determinations of fluorescein circulation time separated by an interval of 1 hour are essential. If the second circulation time is longer than the first and both are over 30 seconds, the animal will not survive without therapy. On the other hand, if the second circulation time is below 25 seconds or is considerably shorter than the first, the prognosis is good. In many of these experiments the change in circulation time appeared to be the earliest index of eventual recovery or death. It gave a clue to the fate of the animal when no decisive judgment could be made from the blood pressure and heart rate. In three dogs the cyanide and fluorescein circulation times were compared during shock. It was found that the cyanide circulation time, though increased in shock, remained at a fairly constant value while over the same period the fluorescein circulation time showed progressive changes. This discrepancy between the cyanide and fluorescein methods may be explained by the fact that the former does not include the minute peripheral systemic circulation. Since the study of shock is concerned with tissue anoxia and is primarily a phenomenon of the failure of the peripheral circulation, it is important to choose procedures such as the fluorescein method as a measure of the condition of the peripheral vascular system.

THYROTROPHIC HORMONE ACTIVITY IN HYPOPHYSECTOMIZED RATS EXPOSED TO COLD AND RECEIVING ASCORBIC ACID

1958 ◽  
Vol 36 (11) ◽  
pp. 1099-1104
Author(s):  
André DesMarais
Keyword(s):  
Ascorbic Acid ◽  
Thyroid Hormones ◽  
Room Temperature ◽  
Hormone Activity ◽  
Exposure To Cold ◽  
Thyrotrophic Hormone ◽  
Hypophysectomized Rats

Hypophysectomized rats were treated for 5 days with 0.05 unit of thyrotrophic hormone (TSH) daily, with or without administration of 150 mg of ascorbate per day, and either exposed to cold (14 °C) or kept at room temperature (24 °C). No effect of exposure to cold or ascorbate treatment could be observed on the thyroid–TSH relationship. Any effect of ascorbate treatment in these animals appears to be mediated through the circulating thyroid hormones.

Experimental Studies on the Superelastic Properties of SMA Material

2010 ◽  
Vol 163-167 ◽  
pp. 2891-2895
Author(s):  
He Meng ◽  
Kun Yang ◽  
She Liang Wang
Keyword(s):  
Chemical Composition ◽  
Room Temperature ◽  
Experimental Studies ◽  
Experimental Results ◽  
Made In China ◽  
Made In

A kind of SMA material with the chemical composition of Ti-51% at Ni (made in china) which is austenitic at room temperature is tested to find out the influences of adding/unloading frequency, loading amplitude and adding/unloading cycles on the superelasitc properties of it. Then the conclusions were made according to the experimental results given in the paper. Finally, some suggestions to improve the performance of the SMA material were offered.

Positron Lifetime Studies of Polyaniline Conducting Polymers

1995 ◽  
Vol 413 ◽  
Author(s):  
C. M. Huang ◽  
J. Liu ◽  
T. C. Sandreczki ◽  
Y. C. Jean
Keyword(s):  
Positron Annihilation ◽  
Room Temperature ◽  
Positron Lifetime ◽  
The Other ◽  
Chemical Compositions ◽  
Lifetime Measurements ◽  
Positron Annihilation Lifetime ◽  
Positron Lifetimes ◽  
Lifetime Studies ◽  
Made In

ABSTRACTPositron annihilation lifetime measurements are made in a series of polyaniline polymers with different chemical compositions and protonation ratios at room temperature. Two positron lifetimes are observed in these materials: one is assigned to annihilation in the bulk and the other to voids created due to protonation. A relationship between conductivities and positron annihilation probabilities is found.

scholarly journals Studies on the Stability of Vitamin C at Elevated Concentrations in Canned Tropical Fruit Juices and Nectars

1969 ◽  
Vol 48 (4) ◽  
pp. 327-336
Author(s):  
Abdul R. Rahman ◽  
J. Anziani ◽  
E. Díaz Negrón
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Room Temperature ◽  
Fruit Juices ◽  
The Other ◽  
Tropical Fruit ◽  
The Stability ◽  
Different Levels

Studies were conducted to determine the stability of vitamin C at elevated concentrations in canned tropical fruit juices and nectars. Canned guava nectar, as well as juices of orange, tomato, and pineapple were fortified with ascorbic acid at seven different levels ranging from the original content present in the samples to about 300 mg. per 100 ml. Half of the samples were stored at room temperature and the other similar half at 100°F. for a period of 6 months. The results indicated that the losses of vitamin C were higher in the samples stored at 100°F. than in those stored at room temperature—regardless of the level of concentration. However, in the guava nectar the percentage of vitamin C destruction was relatively higher at lower concentrations and lower at higher concentrations at both temperatures. No such pattern could be observed in the juices. But the losses of vitamin C in the juices at all levels of concentration ranged below 30 percent at room temperature and below 40 percent at 100°F. This is relatively less than the losses that occurred in the guava nectar.

Intraventricular blood pressures in the chicken

1960 ◽  
Vol 198 (1) ◽  
pp. 153-154 ◽  
Author(s):  
H. E. Bredeck
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Pressure ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
The Other ◽  
Blood Pressures ◽  
Left And Right ◽  
The Right ◽  
Made In

Direct heart punctures were made in two groups of unanesthetized chickens to determine the left and right intraventricular blood pressures. One group was composed of nonlaying birds 28–30 weeks old and the other of laying hens 65–67 weeks of age. Heart rates and the respiratory influence on pressure were also measured. Average pressures obtained were 144/0 and 21/ - 1 mm Hg for the left and right ventricle, respectively. Respiratory efforts caused a mean fluctuation in systolic pressure of approximately 8 mm Hg in the left ventricle and 4 mm Hg in the right. With the exception of the right ventricular diastolic blood pressure, there were no significant pressure or pulse rate differences between the two groups. The heart rate and left ventricular pressure were found to be significantly correlated ( P < .01) in both groups of birds.

THYROTROPHIC HORMONE ACTIVITY IN HYPOPHYSECTOMIZED RATS EXPOSED TO COLD AND RECEIVING ASCORBIC ACID

1958 ◽  
Vol 36 (1) ◽  
pp. 1099-1104
Author(s):  
André DesMarais
Keyword(s):  
Ascorbic Acid ◽  
Thyroid Hormones ◽  
Room Temperature ◽  
Hormone Activity ◽  
Exposure To Cold ◽  
Thyrotrophic Hormone ◽  
Hypophysectomized Rats

Hypophysectomized rats were treated for 5 days with 0.05 unit of thyrotrophic hormone (TSH) daily, with or without administration of 150 mg of ascorbate per day, and either exposed to cold (14 °C) or kept at room temperature (24 °C). No effect of exposure to cold or ascorbate treatment could be observed on the thyroid–TSH relationship. Any effect of ascorbate treatment in these animals appears to be mediated through the circulating thyroid hormones.

Effects of Pulsed Magnetic Treatment on Mechanical Characteristics of Manufactured Parts

2006 ◽  
Author(s):  
Barney E. Klamecki
Keyword(s):  
Room Temperature ◽  
Mechanical Characteristics ◽  
Experimental Studies ◽  
Magnetic Treatment ◽  
The Other ◽  
Thin Wall ◽  
Qualitative Explanation ◽  
The Difference ◽  
And Performance ◽  
And Control

The use of magnetic fields to treat manufactured parts is attractive since easy-to-produce, easy-to-control fields can be used at room temperature, in contrast to more complex treatments such as heat treatment. Little research has been done to apply magnetic treatment to the modification and control of mechanical properties, behavior and performance of manufactured parts. This paper contains descriptions of experimental studies of the effects of pulsed magnetic treatment on the residual stress in machined surfaces and in welded thin-wall tubes, and includes a qualitative explanation of some of the results in terms of dislocation density. The machined part results indicated only possibly small effects, and so further experiments were done with thin-wall tubes that were expected to be more susceptible to magnetic treatment, and a more sensitive measurement technique was used. The difference in damping of vibration of untreated and pulsed magnetically treated welded tubes was used as a measure of treatment effects. Two significant results are reported. One is that pulsed magnetic treatment increased damping by up to 20%, with smaller effects in most tests. The other result is that damping increased, decreased, increased, and so on, as the length of magnetic treatment was increased.

scholarly journals The Influence of Storage of Pawpaw Carica papaya Fruit on the Bioactive Components, Antioxidative Properties and Inhibition of Fe2+-Induced Lipid Peroxidation of Water-Extracts of Pawpaw Seed

2016 ◽  
Vol 59 (3) ◽  
pp. 146-154
Author(s):  
Foluso Olutope Adetuyi ◽  
Abimbola Olawumi Iroaye ◽  
Olamide Muyiwa Babatunde ◽  
Gloria Jacinta Effiong
Keyword(s):  
Lipid Peroxidation ◽  
Ascorbic Acid ◽  
Room Temperature ◽  
Carica Papaya ◽  
Water Extract ◽  
The Other ◽  
Bioactive Components ◽  
Flavonoid Content ◽  
Antioxidative Properties ◽  
Water Extracts

Freshly harvested, matured, newly ripe pawpaw (Carica papaya) fruit (Maradol variety) wasstored at room temperature (27±1 °C) for 7days. The seeds of the freshly harvested and stored pawpawfruit were taken and divided into two groups each; one was dried as dry sample, dry freshly harvestedsample (DFHS) and dry stored sample (DSS) while the other was left as wet sample, wet freshly harvestedsample (WFHS) and wet stored sample (WSS). The bioactive components, antioxidative properties andinhibition of Fe2+ induced lipid peroxidation activity of the water extract of the seed were investigated.Storage of pawpaw fruit caused a significant increase in ascorbic acid and flavonoid content of the pawpawseed in both dry and wet samples but only in dry stored sample significant increase in the phenol contentof the seed was observed. The dried pawpaw seed DFHS and DSS showed stronger inhibition of Fe2+induced lipid peroxidation activities.

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