The effect of temperature on the oxygen consumption of isolated human umbilical arteries

1970 ◽  
Vol 48 (6) ◽  
pp. 377-381 ◽  
Author(s):  
Carol Colthart ◽  
Margot R. Roach
Keyword(s):  
Oxygen Consumption ◽  
Low Temperatures ◽  
Arrhenius Plot ◽  
Post Partum ◽  
Effect Of Temperature ◽  
Metabolic Processes ◽  
Different Temperatures ◽  
High And Low Temperatures ◽  
Umbilical Arteries

The oxygen consumption [Formula: see text] of isolated segments of 40 human umbilical arteries was measured at different temperatures from 5 °C to 37 °C with a modified Fenn microrespirometer. The values varied from 8 μl/g per h at 8 °C to 70 μl/g per h at 37 °C. The Arrhenius plot was nonlinear, and the Q10 varied from 0.11 (30–40 °C) to 1.8 (20–30 °C) and 7.1 (10–20 °C). This suggests that the metabolic processes may be different at high and low temperatures. The results were consistent for at least 5 h post partum, and did not seem to vary from one segment of the cord to another.

The effect of temperature on the consumption of fat during pupal development inGlossina.

1960 ◽  
Vol 51 (3) ◽  
pp. 583-598 ◽  
Author(s):  
E. Bursell
Keyword(s):  
Low Temperatures ◽  
Fat Content ◽  
Effect Of Temperature ◽  
Tsetse Flies ◽  
Optimum Temperature ◽  
Glossina Morsitans ◽  
Pupal Development ◽  
Pupal Period ◽  
Fat Consumption ◽  
Different Temperatures

The size-specific fat content of tsetse flies recently emerged from their puparia was determined and by comparison with the size-specific fat content of newly deposited larvae an estimate was obtained of the consumption of fat during pupal development. Experiments withGlossina morsitansWestw. were carried out at a number of different temperatures and it was found that the amount of fat consumed was least at temperatures between 22 and 24°C.Knowing the duration of the pupal period at different temperatures, the rate of fat consumption could be calculated and the logarithm of this rate was found to be linearly related to temperature. The occurrence of an optimum temperature in respect of fat consumption thus reflects the fact that at high temperatures the rate of fat consumption is greatly increased without a corresponding reduction in the duration of the pupal period, whereas at low temperatures the pupal period is very greatly lengthened without a corresponding decrease in the rate of fat consumption.

scholarly journals Effect of Temperature and Time on Oxygen Consumption by Olive Fruit: Empirical Study and Simulation in a Non-Ventilated Container

Fermentation ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 200
Author(s):  
Eddy Plasquy ◽  
María C. Florido ◽  
Rafael Rubén Sola-Guirado ◽  
José María García Martos ◽  
Juan Francisco García Martín
Keyword(s):  
Oxygen Consumption ◽  
Anaerobic Respiration ◽  
Co2 Production ◽  
Effect Of Temperature ◽  
Critical Threshold ◽  
Irreversible Damage ◽  
Olive Fruit ◽  
Different Temperatures ◽  
Arrhenius Function

Fermentation processes within olive fruit jeopardize the quality of the extracted oil. Aeration, temperature, and time play a crucial role in attaining the critical threshold at which an aerobic respiration shifts towards anaerobic. In this work, the O2 consumption and CO2 production of olive fruit kept in a closed container at different temperatures (5–45 °C) were measured over 7 h. The data allowed us to describe the relationship between the temperature and the respiration rate as an Arrhenius function and simulate the oxygen consumption in the inner part of a container full of fruit with low aeration, considering the generated respiration heat over time. The simulation revealed that olives risk shifting to anaerobic respiration after 3 h at 25 °C and less than 2 h at 35 °C when kept in a non-ventilated environment. The results underline the irreversible damage that high day temperatures can produce during the time before fruit processing, especially during transport. Lowering, as soon as possible, the field temperature thus comes to the fore as a necessary strategy to guarantee the quality of the olives before their processing, like most of the fruit that is harvested at excessive temperatures.

Effect of Temperature and Safeners on Glutathione Levels and Glutathione S-Transferase Activity in Maize

1991 ◽  
Vol 46 (9-10) ◽  
pp. 856-860 ◽  
Author(s):  
Daniel L. Kunkel ◽  
John C. Steffens ◽  
Robin R. Bellinder
Keyword(s):  
Low Temperatures ◽  
Herbicide Tolerance ◽  
Effect Of Temperature ◽  
Transferase Activity ◽  
Glutathione S Transferase ◽  
Different Temperatures ◽  
Maize Plants ◽  
Incubation Temperatures ◽  
Gst Activity

Abstract Studies were conducted to determine the biochemical aspects of chloroacetamide injury to maize and the mechanism by which safeners maintain herbicide tolerance, even at reduced temperatures. The objectives of these studies were threefold: one, determine whether gluta­thione (GSH) content varies in maize plants grown at three different temperatures in safener-treated and non-treated plants; two, determine whether glutathione S-transferase (GST) activ­ity varies in plants grown at different temperatures; and three, determine if GSH activity is sensitive to low temperatures in vitro. The herbicide safeners CGA -154281 [4-(dichloroacetyl)-3,4-dihydro-3-methyl-2 H-1 ,4-benzoxazine] and dichlormid [2,2-dichloro-N,N-di-2-propenylacetamide] were used with metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-n-(2-methoxy-1-methyl)acetamide] or acetochlor [2-chloro-N-(ethoxymethyl)-N-2-ethyl-6-methylphenyl)-acetamide], respectively, to determine the mechanisms of maize tolerance. CGA -154281 signifi­cantly increased GSH levels in maize seedlings grown at 27 °C compared to non-safened seed­lings, however significant differences were not seen at 17 or 37 °C. Dichlormid increased GSH levels by 1.6-fold at all growth temperatures. Both CGA -154281 and dichlormid increased GST activity significantly at all growth temperatures. The safener-induced GST activity was main­tained at in vitro incubation temperatures of 5 and 15 °C for acetochlor and metolachlor, re­spectively. In contrast, GST activity from non-safened tissue was essentially absent at these temperatures. Therefore, greater GST activity following safener treatment may result in higher levels of herbicide metabolism, even at low temperatures.

The effect of temperature on cold hardening of Loliutn perenne seedlings

1980 ◽  
Vol 95 (1) ◽  
pp. 77-81 ◽  
Author(s):  
M. P. Fuller ◽  
C. F. Eagles
Keyword(s):  
Lolium Perenne ◽  
Low Temperatures ◽  
Cold Hardiness ◽  
Leaf Growth ◽  
Effect Of Temperature ◽  
Threshold Temperature ◽  
Screening Techniques ◽  
Temperature Regimes ◽  
Different Temperatures ◽  
Cool Night

SummaryThe variation in hardening responses under different temperature regimes for three cultivars of Lolium perenne L. is described. The relative cold hardiness of the cultivars was modified by different temperatures during hardening. A threshold temperature existed above which hardening did not occur, but this temperature varied between cultivars.Although continuous low temperatures (2 °C) favoured hardening, hardening also occurred under warm day and cool night conditions (15:2 °C) where cultivars showed contrasting hardiness responses in daylengths of 16, 12 and 8 h. Under some of these conditions both leaf growth and hardiness were possible.The significance of these results is discussed in terms of the development of screening techniques and breeding objectives.

scholarly journals The influence of high and low temperatures on the impact properties of glass-epoxy composites

2007 ◽  
Vol 72 (7) ◽  
pp. 713-722 ◽  
Author(s):  
Slavisa Putic ◽  
Marina Stamenovic ◽  
Branislav Bajceta ◽  
Predrag Stajcic ◽  
Srdjan Bosnjak
Keyword(s):  
Low Temperatures ◽  
Composite Structures ◽  
Room Temperature ◽  
Epoxy Composite ◽  
Epoxy Composites ◽  
Temperature Influence ◽  
Impact Properties ◽  
Different Temperatures ◽  
High And Low Temperatures ◽  
The Impact

The aim of this paper is to present the influence of high and low temperatures on the impact properties glass-epoxy composites. The impact strength an is presented for four different glass-epoxy composite structures at three different temperatures, i.e., at room temperature t=20?C, at an elevated temperature t=+50?C and at a low temperature t=-50?C. Standard mechanical testing was carried out on the composite materials with specific masses of reinforcement of 210 g m-2 and 550 g m-2 and orientations 0?/90? and ?45?. Micromechanical analysis of the failure was performed in order to determine real models and mechanisms of crack and temperature influence on the impact properties. .

scholarly journals Oxygen consumption and ammonia excretion of the searobin Prionotus punctatus (Scorpaeniformes, Triglidae) at two different temperatures

1999 ◽  
Vol 47 (2) ◽  
pp. 127-136 ◽  
Author(s):  
Vicente Gomes ◽  
Phan Van Ngan ◽  
Maria José de Arruda Campos Rocha Passos ◽  
Liliana Lucia Christina Forneris
Keyword(s):  
Experimental Data ◽  
Oxygen Consumption ◽  
Energy Expenditure ◽  
Energy Budget ◽  
Ammonia Excretion ◽  
South Atlantic ◽  
Weight Class ◽  
Metabolic Processes ◽  
Different Temperatures

Routine oxygen consumption and ammonia excretion were measured at 20ºC and 25ºC in the searobin Prionotus punctatus collected in Ubatuba region (22º30'S), SP, Brazil, in western South Atlantic, to investigate energy expenditure and losses through metabolic processes. IndividuaIs ranging from 1.00g to 88.47g and from 1.79g to 56.50g were used in experiments at 20ºC and 25ºC, respectively. At 20ºC and 25ºC, the averages of weight-specific oxygen consumption for the weight class of 1.00 - 10.00g, common to both temperatures, were 162.46µ 39.51 µ.10z/g/h and 200.47µ 92.46 µ.10z/g/h, respectively; for the weight class of 50.01 - 60.00g these values were 112.30 µ 22.84 µ.10z/g/h and 114.60 µ 20.36 µ.10zlg/h. At 20ºC and 25ºC, the averages of weight-specific ammonia excretion for the weight class of 1.00 to 1O.00g were 1.03 µ 0.37 fJ.M/g/h and 1.21 µ 0.65 µ.M/g/h, respectively; for the weight class of 50.01 -60.00g these values were 0.68 µ 0.13 fJ.M/g/h and 0.60 µ 0.22 µ.M/g/h. The energy budget for the species was calculated at both temperatures using the experimental data and a model for marine teleosts proposed in the literature.

scholarly journals Rheological Evaluation of Modified Bitumen by EVA and Crumb Rubber Using RSM Optimization

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Mohamad H. Dehnad ◽  
Behrouz Damyar ◽  
Hossein Z. Farahani
Keyword(s):  
Low Temperatures ◽  
Ethylene Vinyl Acetate ◽  
Crumb Rubber ◽  
Test Results ◽  
Modified Bitumen ◽  
Rsm Optimization ◽  
Different Temperatures ◽  
Creep Stiffness ◽  
Optimal Values ◽  
High And Low Temperatures

In the present study, ethylene-vinyl acetate (EVA) and crumb rubber (CR) were used as bitumen modifiers. The experiment was designed by response surface methodology (RSM) at different levels of modifier additives based on the central composite design (CCD). Next, the Superpave protocol was followed to evaluate the modified bitumen performance at different temperatures compared with the unmodified bitumen. In this regard, to evaluate at high temperatures, a dynamic shear rheometer (DSR) test was performed, and G ∗ /sinδ index was examined on bitumen samples after aging. Besides, the bending beam rheometer (BBR) test was performed to evaluate the low-temperature behaviour of the modified bitumen according to the SHRP standard based on the creep stiffness and creep rate. The optimal combination of additives was evaluated using RSM and analysis of statistical values to improve the performance properties of bitumen at high and low temperatures. Moreover, based on the DSR and BBR test results, 5.6% of EVA and 3.9% of CR were selected as the optimal values for the modified bitumen behaviour at the high and low temperatures of the mixture.

scholarly journals Butyl Rubber-Based Composite: Thermal Degradation and Prediction of Service Lifetime

2019 ◽  
Vol 3 (2) ◽  
pp. 48 ◽  
Author(s):  
Phuong Nguyen-Tri ◽  
Ennouri Triki ◽  
Tuan Anh Nguyen
Keyword(s):  
Arrhenius Plot ◽  
Polymer Network ◽  
Crosslinking Density ◽  
Butyl Rubber ◽  
Metalworking Fluids ◽  
Effect Of Temperature ◽  
Service Lifetime ◽  
Metalworking Fluid ◽  
Rubber Composite ◽  
Different Temperatures

Butyl rubber-based composite (BRC) is one of the most popular materials for the fabrication of protective gloves against chemical and mechanical risks. However, in many workplaces, such as metal manufacturing or automotive mechanical services, its mechanical hazards usually appear together with metalworking fluids (MWFs). The presence of these contaminants, particularly at high temperatures, could modify its properties due to the scission, the plasticization and the crosslinking of the polymer network and thus lead to severe modification of the mechanical and physicochemical properties of material. This work aims to determine the effect of temperature and a metalworking fluid on the mechanical behavior of butyl rubber composite, dealing with crosslinking density, cohesion forces and the elastic constant of BRC, based on Mooney–Rivlin’s theory. The effect of temperature with and without MWFs on the thermo-dynamical properties and morphology of butyl membranes was also investigated. The prediction of service lifetime was then evaluated from the extrapolation of the Arrhenius plot at different temperatures.

scholarly journals Temperature and Exports: Evidence from the United States

2021 ◽  
Author(s):  
Jimmy Karlsson
Keyword(s):  
United States ◽  
Low Temperatures ◽  
The United States ◽  
Effect Of Temperature ◽  
Negative Effects ◽  
Short Term ◽  
High Resolution Data ◽  
Temperature Changes ◽  
Micro Level ◽  
High And Low Temperatures

AbstractThis paper estimates the effect of exogenous short-term temperature changes on the economy of the United States, using high-resolution data on monthly exports which has not been previously exploited in the literature. The detailed disaggregation of U.S. export data into sectors enables a top-down estimation of the net effect of temperature, while also identifying potential mechanisms at the micro level. Using an econometric specification which allows high parametric flexibility, I find significantly negative effects of both high and low temperatures. The magnitude of the effects corresponds to an average reduction of annual U.S. exports by 0.20%, following a uniform 2 $$^{\circ }$$ ∘ C temperature increase. Industry heterogeneity in the temperature effect suggests disparate mechanisms behind hot and cold days, which are important to take into account when estimating the future economic damages of climate change in the United States.

Sign in / Sign up

Export Citation Format

Share Document