The effect of γ-ray irradiation on the microstructure and thermal properties of polyacrylonitrile fibers

RSC Advances ◽  
2015 ◽  
Vol 5 (30) ◽  
pp. 23508-23518 ◽  
Author(s):  
Weizhe Zhao ◽  
Yonggen Lu ◽  
Junqi Jiang ◽  
Leiyang Hu ◽  
Liangxiao Zhou
Keyword(s):  
Thermal Properties ◽  
Intramolecular Cyclization ◽  
Low Doses ◽  
Solubility Measurement ◽  
Γ Ray ◽  
Higher Doses ◽  
Intermolecular Crosslinking ◽  
Pan Fibers

After γ-ray irradiation, the intramolecular cyclization of PAN fibers was dominant at relatively low doses (<200 kGy), while intermolecular crosslinking in amorphous regions dominated at higher doses, according to the solubility measurement.

Involvement of 5-Hydroxytryptamine in Platelet Aggregation In Vivo in Rats and Guinea Pigs

1989 ◽  
Vol 61 (03) ◽  
pp. 463-467 ◽  
Author(s):  
G M Smith
Keyword(s):  
Platelet Count ◽  
Guinea Pigs ◽  
Platelet Adhesion ◽  
Adenosine Diphosphate ◽  
Rate Of Return ◽  
Low Doses ◽  
Dose Dependent ◽  
Higher Doses ◽  
Rat Platelets

SummaryIn this study, 5-hydroxytryptamine (5-HT) caused a dose- dependent fall in the circulating platelet count suggesting that 5-HT receptors are activated in rat platelets to cause platelet adhesion and aggregation. When low doses of adenosine diphosphate (ADP) were simultaneously injected with 5-HT, there was a significant potentiation of the responses to ADR Ketanserin significantly reduced the potentiated responses. When higher doses of ADP were infused with bolus injections of 5-HT there was no potentiation and ketanserin did not reduce these responses. Ketanserin did not inhibit the collagen-induced fall in circulating platelet count, but did significantly increase the rate of return to the basal platelet count compared with control. 5-HT did not cause a fall in platelet count in guinea-pigs

Effect of insulin on free fatty acid uptake by hepatocytes in the duck

1984 ◽  
Vol 102 (3) ◽  
pp. 381-386 ◽  
Author(s):  
R. Gross ◽  
P. Mialhe
Keyword(s):  
Fatty Acids ◽  
Growth Hormone ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Glucose Metabolism ◽  
Free Fatty Acids ◽  
Fatty Acid Uptake ◽  
Acid Uptake ◽  
Low Doses ◽  
Higher Doses

ABSTRACT To elucidate the hypolipacidaemic effect of insulin in ducks, its action on the uptake of free fatty acids (FFA) by duck hepatocytes was determined. At low doses (10 mu./l) insulin stimulated FFA uptake. This effect was not observed with higher doses of insulin (20, 30 and 50 mu./l). Growth hormone at physiological concentrations and corticosterone (14·4 nmol/l) decreased basal activity, probably by reducing glucose metabolism and consequently α-glycerophosphate (α-GP) supply. Insulin was able to reverse the inhibition induced by GH and corticosterone on both FFA uptake and α-GP production. These results therefore suggest that the hypolipacidaemic effect of insulin may be partly mediated by its action on hepatic FFA uptake. J. Endocr. (1984) 102, 381–386

Effect of methacholine chloride on rheology and transport of canine tracheal mucus

1979 ◽  
Vol 47 (1) ◽  
pp. 26-31 ◽  
Author(s):  
M. King ◽  
N. Viires
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Base Line ◽  
Low Doses ◽  
Mucociliary Transport ◽  
Frog Palate ◽  
High Doses ◽  
Tracheal Mucus ◽  
Higher Doses ◽  
Cytology Brush

The effect of methacholine chloride (M) on tracheal mucus was investigated in three conscious tracheostomized dogs. Aerosols of M in concentrations of 2--32 mg/ml were delivered intratracheally for 1 min. Mucus was sampled with a cytology brush at 2 min postchallenge and at irregular intervals thereafter. The mechanical properties of each sample were determined in the magnetic microrheometer, and correlated with mucociliary transportability as assayed by the frog palate technique. With high doses of M, there was an increase in volume of secretion collected per unit time. The elastic modulus (G′) at 2 min postchallenge went up (to 1.5 x 2.3 x control for 16 and 32 mg/ml, respectively) then fell below control before returning to base line after 30 or 45 min. With low doses of M (2--8 mg/ml) the secretion rate was also above control, but only a decrease in G′ (to 0.54 x control) was observed. The decrease in G′ at low doses did not significantly alter the frog palate transport rate; however, the increase at higher doses did impede mucociliary transport.

Effects of acetazolamide and metabolic acidosis and alkalosis upon gastric acid secretion

1962 ◽  
Vol 202 (3) ◽  
pp. 429-436 ◽  
Author(s):  
Frank M. Byers ◽  
Paul H. Jordan ◽  
Thomas H. Maren
Keyword(s):  
Metabolic Acidosis ◽  
Carbonic Anhydrase ◽  
Acid Secretion ◽  
Metabolic Alkalosis ◽  
Suppressive Effect ◽  
Low Doses ◽  
Heidenhain Pouch ◽  
Feeding Experiments ◽  
Initial Reduction ◽  
Higher Doses

The gastric H+ secretory responses to i.v. HCl, NaHCO3, and acetazolamide were studied in Heidenhain-pouch dogs that had been stimulated to secrete by feeding. Acetazolamide in low doses (5 mg/kg) gave a 65% reduction in H+ output for 2–4 hr, after which H+ secretion increased above normal, coincident with renal HCO3– loss and metabolic acidosis. Higher doses produced a greater systemic acidosis and resulted in less initial reduction of H+ and greater augmentation. Doses of 75–100 mg/kg, given 17 hr before feeding to produce a systemic acidosis, resulted in increased secretion, even though sufficient drug remained in the plasma to inhibit tissue carbonic anhydrase. Metabolic acidosis (i.v. HCl) initially suppressed but later augmented gastric H+. Acetazolamide had no suppressive effect in the presence of either an HCl- or acetazolamide-induced acidosis. Metabolic alkalosis (i.v. NaHCO3) reduced gastric H+ in regular feeding experiments and in dogs made acidotic by acetazolamide.

scholarly journals The action of prolyl-leucyl-glycinamide (PLG) on the nigrostriatal pathway of the rat

1990 ◽  
Vol 48 (2) ◽  
pp. 156-160
Author(s):  
João S. Pereira ◽  
Luiz Augusto F. Andrade ◽  
Paulo H. F. Bertolucci ◽  
J. Geraldo Camargo Lima ◽  
Henrique B. Ferraz
Keyword(s):  
Wistar Rats ◽  
Electrolytic Lesion ◽  
Behavior Model ◽  
Low Doses ◽  
Nigrostriatal Pathway ◽  
Rem Sleep Deprivation ◽  
Hypothalamic Region ◽  
Male Wistar Rats ◽  
6 Hydroxydopamine ◽  
Higher Doses

In order to study the nigrostriatal pathway, we obtained the rotatory behavior model in male Wistar rats by electrolytic lesion of the left lateral hypothalamic region. Animals thus lesioned displayed rotations toward the same side of lesion when apomorphine was administered, a result in disagreement with what has been obtained in the model with 6-hydroxydopamine lesion. The administration of PLG alone was not followed by rotatory behavior but when the compound was administered in low doses (0.25 to 1mg/kg) simultaneously with apomorphine to animals previously submitted to REM sleep deprivation, a significant increase in the number of rotations was observed in comparison with controls and groups receiving higher doses of PLG. These results indicate that PLG may act as, a modulator on dopamine receptors in the striatum.

Biphasic response to acetylcholine in human veins in vivo: the role of the endothelium

1990 ◽  
Vol 78 (1) ◽  
pp. 101-104 ◽  
Author(s):  
Joe Collier ◽  
Patrick Vallance
Keyword(s):  
Dose Response ◽  
Distilled Water ◽  
Low Doses ◽  
Biphasic Response ◽  
Dorsal Hand ◽  
Before And After ◽  
Higher Doses ◽  
Made In

1. The dose-response to acetylcholine has been examined in dorsal hand veins of healthy volunteers before and after removal of the endothelium. 2. Measurements were made in single dorsal hand veins during local infusions of acetylcholine. The vein was irrigated with distilled water to remove the endothelium. Dilator studies were performed in vessels preconstricted by a continuous infusion of noradrenaline. 3. In the endothelium-intact vessel the dose-response to acetylcholine was biphasic; low doses produced venodilatation with higher doses causing venoconstriction. 4. Dilatation to low doses of acetylcholine was abolished by prior irrigation with distilled water, consistent with denudation of the endothelium by this process. Irrigation augmented the constriction seen in response to higher doses of acetylcholine. 5. This is the first demonstration of an endothelium-dependent biphasic dose-response to acetylcholine in man. The results raise questions as to the possible physiological actions of endogenous acetylcholine and as to the use of the acetylcholine dose-response curve as a marker of endothelial function.

Distribution and function of enteric GAL-IR nerves in dogs: comparison with VIP

1989 ◽  
Vol 256 (5) ◽  
pp. G884-G896 ◽  
Author(s):  
T. Gonda ◽  
E. E. Daniel ◽  
T. J. McDonald ◽  
J. E. Fox ◽  
B. D. Brooks ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Small Intestine ◽  
Gastrointestinal Tract ◽  
Vasoactive Intestinal Polypeptide ◽  
Myenteric Plexus ◽  
Low Doses ◽  
Field Stimulation ◽  
And Function ◽  
Higher Doses ◽  
Stimulation Of

The distribution of nerves containing galanin-immunoreactive (GAL-IR) material was compared to the distribution of neurons containing vasoactive intestinal polypeptide (VIP) immunoreactivity in the canine gastrointestinal tract. The actions of intra-arterially administered galanin and VIP on motility in the gastric antrum and corpus and the intestines were also studied. All sphincter muscles contained galanin- and VIP-immunoreactive nerve profiles. VIP-immunoreactive nerve profiles were present in all layers of the stomach, small intestine, and colon. GAL-IR nerve somata were common in the submucous plexus of ileum and colon and in the myenteric plexus of the terminal antrum, as were nerve processes in various layers. In the small intestine, galanin inhibited contractile responses to field stimulation of intrinsic nerves and also reduced the contractions after nerve blockade with tetrodotoxin (TTX). VIP often enhanced field-stimulated contractions at low doses but inhibited these and the contractions after TTX at higher doses. In the stomach and colon, both peptides inhibited responses to field stimulation; whether these effects were due to actions on smooth muscle was not tested. The distribution and actions of galanin in gut are consistent with the hypothesis that it acts at smooth muscle sites and possibly at prejunctional sites.

Regulation of food intake by metabolic fuels in white-crowned sparrows

1995 ◽  
Vol 269 (6) ◽  
pp. R1462-R1468 ◽  
Author(s):  
T. Boswell ◽  
R. D. Richardson ◽  
R. J. Seeley ◽  
M. Ramenofsky ◽  
J. C. Wingfield ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Food Intake ◽  
Carbohydrate Metabolism ◽  
Plasma Lipids ◽  
Migratory Birds ◽  
Low Doses ◽  
Fatty Acid Utilization ◽  
Increase Food Intake ◽  
Fat Stores ◽  
Higher Doses

Migratory birds rely on increased fat storage and fatty acid utilization to meet seasonal changes of energy expenditure and as a result increase food intake and fat stores before migration. To determine whether their feeding behavior is sensitive to carbohydrate and/or fatty acid utilization, white-crowned sparrows maintained on short daylength (9L15D) were injected intraperitoneally with 2-deoxy-D-glucose (2-DG) or 2,5-anhydro-D-mannitol (2,5-AM). Low doses of 2-DG (25 or 50 mg/kg) had no effect on food intake, and higher doses (100 or 300 mg/kg) significantly suppressed feeding after 1 and 2 h. No dose of 2-DG increased meal size. Similarly, low doses of 2,5-AM (25, 50, or 100 mg/kg) had no effect on food intake, and higher doses (300 and 600 mg/kg) significantly suppressed intake. These data suggest that decreased carbohydrate metabolism does not elicit feeding in this species. Importantly, these drugs, as well as insulin and glucagon, were demonstrated to increase plasma fatty acids as well as to decrease feeding. Injections of tributyrin (100, 300, 600, or 2,000 mg/kg i.p.) or glycerol (300, 450, and 600 mg/kg) also significantly suppressed 60-min and 120-min food intake dose dependently in these birds, and equimolar glucose (1,200 mg/kg) had no effect. We conclude that feeding by the white-crowned sparrow is unresponsive to manipulations of carbohydrate metabolism and is decreased after manipulations that increase plasma lipids.

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