The effect of submaximal temperature on thermotolerant yeasts

Significant differences in whole brain and in brain area acetylcholine concentration have been observed between the two strains of rats selectively bred for differences in speed of acquisition of conditioned avoidance. Brain acetylcholinesterase activity was similar in the strains. The strain showing poor conditioned avoidance behaviour possessed the highest brain concentration of acetylcholine. The finding supports a theory which describes a central cholinergic inhibitory system which may be active in the control of certain types of learning behaviour.     

The effect of age and temperature on mdx muscle fatigue

We have studied the in vitro contractile and fatigue characteristics of extensor digitorum longus (EDL) muscles from 8- and 62-week-old dystrophin-deficient (mdx) and control mice at 20 degrees C and 35 degrees C. There were no differences in fatigability at 20 degrees C, but at 35 degrees C the dystrophin-deficient muscles demonstrated increased fatigability compared to controls, with the older mice exhibiting the greatest fatigue. These results suggest a temperature-related mechanism of myofibrillar fatigue in dystrophin-deficient EDL muscles.     

The effect of frequency on the elevated temperature fatigue of a nickel-base superalloy

In this investigation, the effect of a frequency variation between 2 cpm and 6 × 10⁴ cpm on the 1400°F fatigue properties of wrought Udimet 700 was determined at a constant stress range of 85 ksi. It was found that a peak existed in the cyclic life vs frequency curve such that a) an increase in frequency from 2 to 600 cpm increased the fatigue life 100 times and b) an increase in frequency from 600 to 6 × 10⁴ cpm reduced the fatigue life sevenfold. The peak in the cyclic life vs frequency curve is the result of two competing processes: 1) there is a reduction in the effects of creep and oxidation with increased frequency that tends to increase the life and 2) there is an increase in the heterogeneity of deformation with increased frequency that tends to reduce the life. At low frequencies, crack initiation occurred at surface-connected grain boundaries. Crack propagation was initially intergranular and then proceeded noncrystallographically normal to the stress axis (Stage II mode). Crack initiation at high frequencies occurred at subsurface brittle phases located at grain boundaries or at the intersection of coherent annealing twin boundaries. Crack propagation was entirely transgranular, proceeding initially along twin boundaries or slip bands (Stage I mode) and then changing to the Stage II mode. The statistical nature of the fracture process, the significance of subsurface crack initiation, and the relation of these results to existing high temperature fatigue models are discussed.     

The effect of temperature on the pattern of torpor in a marsupial hibernator

The feeling that life has had no meaning is an impediment to a peaceful death. Life review enables a person to identify events that have been of worth and so enhances self-esteem. This approach has been extended and formalized by establishing a biographer service to compile oral and written biographies of patients who may be expected to benefit from such a re-examination of their lives. The service is now also being offered to patients whose disability precludes most other forms of activity. The value of biography as therapy is considered and it is concluded that it has much to offer in the circumstances described.     

The effect of the thermal path to reach isothermal temperature on transformation kinetics

Experimentally determined isothermal transformation (IT) diagrams are valid only for a precisely described experimental condition; they are dependent on these conditions(e.g., the thermal path) and do not simply characterize the transformation. The concept of the true IT diagram, which depends only on the material considered and which characterizes the transformation independently of the experiment’s condition, is presented. On the basis of the true IT diagram, it is possible to predict and derive (1) the influence of the thermal path to reach isothermal temperature on transformation kinetics, (2) the kinetics of the transformation during continuous change of temperature, and (3) the influence of the temperature at which heat treatment starts on the experimental transformation diagram. Factors that influence a shape of experimental diagrams are discussed. It has been found that the most important ones are the shape of the true transformation diagram and the sign of temperature change (plus for heating, minus for cooling). Experimental transformation kinetics depend on overall activation energy, rate constant, and the time exponent derived for true transformation kinetics. Formerly with the Laboratory of Metallurgy, Delft University of Technology, 2628 AL Delft, The Netherlands     

The effect of concentration and temperature on diffusivity of metal compounds

The effect of concentration and temperature on diffusivity of various metal compounds which are frequently used in hydrometallurgical applications has been investigated. A diaphragm cell technique has been adopted in this study. Diffusivity of cobalt, nickel, copper, and iron compounds was measured in water with and without ammonia. The effect of chloride, nitrate, and sulfate on diffusivity of these metals in the above-mentioned solutions was studied. The effect of cyanide concentration on diffusivity of gold, silver, copper, and iron in solution was also investigated. The range of the concentration of solutions used in this study was 10^-4 to 0.5 M. Temperature was varied between 15 °C and 45 °C. An empirical model for metal chloride, nitrate, and sulfate systems has been developed to predict diffusivity of various metal compounds when concentration, charge, size, and mobility of diffusing species are known. The predicted values of diffusivity of numerous metal compounds by this model are in good agreement with the observed values for the ionic strength less than 0.5 M. Formerly Research Fellow, Department of Metallurgical Engineering, South Dakota School of Mines and Technology     

The effect of temperature on potassium chloride contracture in cat myocardium

1. Contracture was induced in cat myocardium by exposure to 140 mM-KC1 In isotonic Tyrode solution. Force of contracture expressed as mg/mm2 (muscle cross-sectional area) falls with increasing cross-sectional area. 2. The effect of temperature on isometric force developed during contracture was evaluated both in normal (untreated) atrial and ventricular muscle and following treatment with sympatholytic drugs. 3. The force of contracture was not significantly affected by sympatholytic drugs at 36 degrees C. 4. In normal atrial and ventricular muscle, force of contracture decreased when the muscle was cooled from 36 to either 29 or 20 degrees C. 5. In atrial muscle, the effect of temperature was not changed by sympatholytic drugs. In contrast, exposure to sympatholytic drugs increased contracture force developed by ventricular muscle at 20 degrees C. Also, contracture force was significantly greater at 20 than at 36 degrees C in ventricular muscle from reserpine-pretreated cats. 6. It is suggested that ventricular muscle becomes more sensitive to the relaxing effects of endogenous catecholamines at temperature is lowered. 7. The differences shown between atrial and ventricular muscle with respect to the effect of temperature and sympatholytic drugs on contracture force may result from the differing amounts of sarcoplasmic reticulum found in these types of cardiac muscle and also from different mechanisms of "excitation-contracture" coupling in atrial and ventricular muscle.     

The effect of intercritical annealing temperature on the structure of niobium microalloyed dualphase steel

The structures produced in a Nb-microalloyed steel by oil quenching after intercritical anneals at 760 and 810 °C have been examined by light and transmission electron microscopy. After both anneals, the periphery of the austenite pool transforms on cooling to ferrite in the same orientation as the ferrite retained during intercritical annealing. Thus the ferrite forms by an epitaxial growth mechanism without the formation of a new interface or grain boundary. The new ferrite is precipitate-free in contrast to the retained ferrite which develops a very dense precipitate dispersion during intercritical annealing. In the carbonenriched interior of the austenite pool beyond the epitaxial ferrite only martensite forms in specimens annealed at 760 °C but various mixtures of ferrite and cementite form in specimens annealed at 810 °C. The latter structures include lamellar pearlite, a degenerate pearlite, and cementite interphase precipitation. All Nb is in solution in the austenite formed at 810 °C, and therefore the low hardenability of the specimens annealed at that temperature is best explained by the effect of low austenite carbon content.     

The effect of external pressure on skin temperature distribution by thermography

1) Serial thermograms were taken after the application of various intensities and durations of localized pressure on the medial surface of the human forearm. 2) Thermal response of the body surface to localized pressure was quantified. 3) It was found that usually a time period of between 1 to 3 minutes elapsed before the body surface attained a maximum elevation of temperature from the time the localized pressure is removed. 4) It was found that increased intensity of pressure (5 psi vs. 3 psi) and longer duration (20 minutes vs. 10 minutes) caused larger thermal responses. 5) It is suggested that high resolution medical thermography may eventually become a useful tool in the fitting of prosthetic and orthotic devices and for the prediction of pressure sores formation so prophylactic measures can be started immediately on immobilized patients.     

The effect of blood, meconium, and temperature on the rapid surfactant test

Four cases are presented in which intermittent ischemic symptomatology was referable to a cerebral hemisphere. Arteriography in each case showed complete occlusion of the ipsilateral internal carotid artery in the neck with collateral filling of the ipsilateral intracranial carotid artery into the cavernous portion. Endarterectomy was performed successfully in each case from 1 to 5 weeks after the demonstrated complete occlusion. The collateral circulation to the intracranial portion of the internal carotid artery and the probable reasons for the technical success of these operations are discussed.     

The effect of water temperature on immobility in the forced swimming test in rats

In the Porsolt swimming test intact rats acquire and retain the immobile response indistinguishably at 25 and 30 degrees C; at both temperatures retention is abolished by administration of the glucocorticoid antagonist RU38486 and the kappa-selective opiate receptor antagonist MR2266 when given together, but not when either is given alone. At 20 degrees C, however, the animals do not acquire the response, and have levels of retention significantly lower than at the higher temperature. This deficit is not restored by administration of glucocorticoids, kappa-opioid receptor-selective agonists, thyroid hormone or glucose.     

The effect of testing temperature on fracture toughness of austempered ductile iron

The effect of testing temperature (− 150 °C, 25 °C, and + 150 °C) on the fracture toughness of austempered ductile iron (ADI) was studied. Specimens were first austenitized at 900 °C for 1.5 hours and then salt-bath quenched to 360 °C or 300 °C, for 1, 2, or 3 hours of isothermal holding before cooling to room temperature. The resulting matrices of the iron were of upper-ausferrite and lower-ausferrite. It was found that raising the testing temperature to 150 °C from ambient improved the fracture toughness by 18, 30, and 7 pct for the as-cast/lower-ausferrite ADI/upper-ausferrite ADI, respectively. Lowering the testing temperature to −150 °C produced a decrease of −15, −35, and −48 pct. Optical microscopy, X-ray diffraction analysis, and scanning electron microscopy (SEM) fractography were applied to correlate the toughness variation with testing temperatures.     

The effect of temperature fluctuations on the cytoskeletal organisation and chromosomal constitution of the human oocyte

Pseudomonas aeruginosa infections are commonly observed in sepsis, burns, as well as cystic fibrosis (CF). Among the professional phagocytes neutrophils and monocytes are recruited by various chemotactic factors from the cellular environment. Although they provide the first line of host defense excessive neutrophil accumulation seems to be a major cause of pathogenesis during P. aeruginosa infection. Interleukin-8 (IL-8) represents one important chemoattractant for professional phagocytes. To evaluate IL-8 releasability by phagocytes in the context of P. aeruginosa infection and especially of CF, we stimulated human polymorphonuclear neutrophilic granulocytes (PMN) and peripheral blood mononuclear cells (PBMC) as a source for monocytes with clinical P. aeruginosa isolates, with mucoid P. aeruginosa strain (CF3M) and its nonmucoid revertant (CF3), and with purified P. aeruginosa mucoid exopolysaccharide (alginate). A significant increase in IL-8 release as compared to unstimulated cells was observed after an incubation time of 90 min for PMN and after 60 min for PBMC which increased (PMN: up to 60-fold; PBMC: up to 40-fold) over time (up to 4 h). In contrast of PBMC, when PMN were studied, intracellular IL-8 exceeded the IL-8 release in unstimulated as well as in stimulated cells by up to 10-fold. All clinical P. aeruginosa isolates, independent of the clinical source, induced IL-8 release from human PBMC and PMN in a dose- and time-dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of radiofrequency energy on the length and temperature properties of the glenohumeral joint capsule

Two isozymes of mammalian methionine adenosyltransferase, MAT I and MAT III, are expressed solely in adult liver. They are, respectively, tetramers and dimers of a single subunit encoded by the gene MAT1A. A third isozyme, MAT II, contains a catalytic subunit encoded by a separate gene, MAT2A, and is expressed in a variety of tissues, including (to a slight extent) adult liver. Based on a recent finding that 2 children with isolated hypermethioninemia and brain demyelination were homozygous for MAT1A mutations predicted to produce severely truncated proteins, and devoid of activity when expressed, it was concluded that complete lack of MAT I/III activity may be associated with neurological symptoms and demyelination. We now report that a 43-year-old man with persistent isolated hypermethioninemia, previously demonstrated to have deficient MAT activity in his liver, has normal brain myelination on MRI and normal neurological function, despite being homozygous for a 539 TG insertion in exon V of MAT1A, so that the gene is predicted to encode a protein of only 184 rather than the normal 395 amino acids. This patient's exon V mutation was demonstrated by SSCP analysis and verified by sequencing. Both parents are heterozygous for the same insertion. This suggests that MAT1A mutations producing severely truncated proteins do not necessarily produce brain demyelination. This finding has relevance to a previously reported 4-year-old girl who was also homozygous for the 539insTG mutation. Finally, our patient's 7% residual hepatic MAT activity, measured at 1 mM methionine, may reflect the hepatic activity of the more ubiquitous enzyme form, MAT II.     

The effect of austenitizing temperature on the microstructure and mechanical properties of as-quenched 4340 steel

The effect of austenitizing temperature on both the plane strain fracture toughness,K _IC , and the microstructure of AISI 4340 was studied. Austenitizing temperatures of 870 and 1200°C were employed. All specimens austenitized at 1200°C were furnace cooled from the higher austenitizing temperature and then oil quenched from 870°C. Transmission electron microscopy revealed an apparent large increase in the amount of retained austen-ite present in the specimens austenitized at the higher temperature. Austenitizing at 870°C resulted in virtually no retained austenite; only minor amounts were found sparsely scat-tered in those areas examined. A considerably altered microstructure was observed in specimens austenitized at 1200°C. Fairly continuous 100 to 200Å thick films of retained austenite were observed between the martensite laths throughout most of the area exam-ined. Additionally, specimens austenitized at 870°C contained twinned martensite plates while those austenitized at 1200°C showed no twinning. Plane strain fracture toughness measurements exhibited an approximate 80 pct increase in toughness for specimens austen-itized at 1200°C compared to those austenitized at 870°C. The yield strength was unaffected by austenitizing temperature. The possible role of retained austenite and the elimination of twinned martensite in the enhancement of the fracture toughness of those specimens austen-itized at the higher temperature will be discussed.