One why of the warmth of warm-bodied fish

1981 ◽  
Vol 240 (3) ◽  
pp. R151-R155 ◽  
Author(s):  
E. D. Stevens ◽  
F. G. Carey
Keyword(s):  
Oxygen Uptake ◽  
Cell Boundary ◽  
Effect Of Temperature ◽  
Facilitated Diffusion ◽  
High Concentration ◽  
Simple Diffusion ◽  
Present Essay ◽  
Red Muscle ◽  
Long Time

Tunas are unusual among fish in that they are warm bodied. In the present essay we argue that one adaptive advantage to being warm is that the warmth increases the rate of delivery of oxygen from the cell boundary to the mitochondria by myoglobin. This argument is supported by the following. 1) Tuna have extremely high rates of oxygen uptake, much higher than other fish and close to the rates achieved by mammals. 2) Tuna have an extraordinary capacity to maintain high cruising speeds for a long time. 3) Tuna have much red muscle that contains a high concentration of myoglobin. 4) The effect of temperature on simple diffusion of oxygen is very small whereas the potential affect on facilitated diffusion by myoglobin is large.

A study of organo-hectorite clay crystallization

Clay Minerals ◽  
1997 ◽  
Vol 32 (1) ◽  
pp. 29-40 ◽  
Author(s):  
K. A. Carrado ◽  
P. Thiyagarajan ◽  
K. Song
Keyword(s):  
Room Temperature ◽  
Structural Integrity ◽  
Effect Of Temperature ◽  
Clay Layer ◽  
Layer Formation ◽  
Surface Areas ◽  
Line Shape Analysis ◽  
Long Time ◽  
Organometallic Molecules

AbstractA method has been developed to synthesize organo-hectorite clays directly from a Mg-silicate gel containing organic or organometallic molecules that are expected to be incorporated within the interlayer space. Complete crystallization occurs upon aqueous reflux for 48 h. The progress of clay layer formation was monitored by X-ray powder diffraction (XRD), differential thermal gravimetry (DTG), and infrared (IR) spectroscopy. Evidence of clay XRD peaks occurs after just 4 h of hydrothermal treatment, and Mg(OH)2 is no longer observable after 14 h. Observable changes in DTG and IR occur at about this time as well. Warren line-shape analysis of the 110 reflection indicates that when growth is complete the clay lamellae are on average ∼50% and 25% of the size of natural hectorites and montmorillonites, respectively. The N2 BET surface areas for all materials are also compared. Small angle neutron scattering shows that addition of tetraethyl ammonium (TEA) ions does not alter the structural integrity over that of the purely inorganic form of Li-hectorite, but that use of a cationic polymer does significantly alter the microstructure. The effect of temperature is critical, for at room temperature only the layered Mg hydroxide mineral brucite crystallizes unless very long time scales are used. The crystallizations carried out at room temperature show that clay will form after about 3 months, but that the presence of organics (at least TEA) acts to hinder this process greatly. The role of the organic molecules on silicate clay layer formation is compared with the role of organics in zeolite synthesis.

The relationship between cirral activity and oxygen uptake in Balanus balanoides

1965 ◽  
Vol 45 (2) ◽  
pp. 387-403 ◽  
Author(s):  
R. C. Newell ◽  
H. R. Northcroft
Keyword(s):  
Body Weight ◽  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Mantle Cavity ◽  
The Body ◽  
Effect Of Temperature ◽  
Zero Rate ◽  
Rate Of Oxygen Consumption ◽  
The Relationship ◽  
Balanus Balanoides

The rate of cirral beat of Balanus balanoides is related to the logarithm of the body weight as an exponential function. In any one animal, there is little effect of temperature on cirral activity between 7·5° and 10° C. Between 10° and 20° C, however, there is a rapid increase in cirral beat with temperature followed by a fall at temperatures above 20° C.Balanus balanoides exhibits a fast, medium and zero rate of oxygen consumption. These rates of oxygen consumption correspond with (a) normal cirral beating, (b) ‘testing’ activity with no cirral movement, and (c) with the closure of the mantle cavity. Both of the possible levels of oxygen uptake are related to the logarithm of the body weight in a logarithmic fashion over the temperature range 7·5°–22·5° C. Temperature affects the two rates of oxygen consumption differently. In the slower rate (rate B) there is an increase in the rate of oxygen consumption between 7·5° and 14° C but there is no significant increase in the rate of oxygen consumption between 14° and 22·5 C°.

scholarly journals Importance of the Use of Oxidative Stress Biomarkers and Inflammatory Profile in Aqueous and Vitreous Humor in Diabetic Retinopathy

Antioxidants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 891 ◽  
Author(s):  
Ana Karen López-Contreras ◽  
María Guadalupe Martínez-Ruiz ◽  
Cecilia Olvera-Montaño ◽  
Ricardo Raúl Robles-Rivera ◽  
Diana Esperanza Arévalo-Simental ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Diabetic Retinopathy ◽  
High Concentration ◽  
Oxidative Stress Biomarkers ◽  
Retinal Microvasculature ◽  
Tnf Α ◽  
Long Time ◽  
Markers Of Oxidative Stress ◽  
Cyt C ◽  
Inflammatory Profile

Diabetic retinopathy is one of the leading causes of visual impairment and morbidity worldwide, being the number one cause of blindness in people between 27 and 75 years old. It is estimated that ~191 million people will be diagnosed with this microvascular complication by 2030. Its pathogenesis is due to alterations in the retinal microvasculature as a result of a high concentration of glucose in the blood for a long time which generates numerous molecular changes like oxidative stress. Therefore, this narrative review aims to approach various biomarkers associated with the development of diabetic retinopathy. Focusing on the molecules showing promise as detection tools, among them we consider markers of oxidative stress (TAC, LPO, MDA, 4-HNE, SOD, GPx, and catalase), inflammation (IL-6, IL-1ß, IL-8, IL-10, IL-17A, TNF-α, and MMPs), apoptosis (NF-kB, cyt-c, and caspases), and recently those that have to do with epigenetic modifications, their measurement in different biological matrices obtained from the eye, including importance, obtaining process, handling, and storage of these matrices in order to have the ability to detect the disease in its early stages.

scholarly journals The effect of temperature and thermal acclimation on the sustainable performance of swimming scup

2007 ◽  
Vol 362 (1487) ◽  
pp. 1995-2016 ◽  
Author(s):  
Lawrence C Rome
Keyword(s):  
Steady State ◽  
Relaxation Rate ◽  
Power Output ◽  
Muscle Power ◽  
Thermal Acclimation ◽  
The Body ◽  
Effect Of Temperature ◽  
Cold Temperatures ◽  
Duty Cycles ◽  
Red Muscle

There is a significant reduction in overall maximum power output of muscle at low temperatures due to reduced steady-state (i.e. maximum activation) power-generating capabilities of muscle. However, during cyclical locomotion, a further reduction in power is due to the interplay between non-steady-state contractile properties of muscle (i.e. rates of activation and relaxation) and the stimulation and the length-change pattern muscle undergoes in vivo . In particular, even though the relaxation rate of scup red muscle is slowed greatly at cold temperatures (10°C), warm-acclimated scup swim with the same stimulus duty cycles at cold as they do at warm temperature, not affording slow-relaxing muscle any additional time to relax. Hence, at 10°C, red muscle generates extremely low or negative work in most parts of the body, at all but the slowest swimming speeds. Do scup shorten their stimulation duration and increase muscle relaxation rate during cold acclimation? At 10°C, electromyography (EMG) duty cycles were 18% shorter in cold-acclimated scup than in warm-acclimated scup. But contrary to the expectations, the red muscle did not have a faster relaxation rate, rather, cold-acclimated muscle had an approximately 50% faster activation rate. By driving cold- and warm-acclimated muscle through cold- and warm-acclimated conditions, we found a very large increase in red muscle power during swimming at 10°C. As expected, reducing stimulation duration markedly increased power output. However, the increased rate of activation alone produced an even greater effect. Hence, to fully understand thermal acclimation, it is necessary to examine the whole system under realistic physiological conditions.

Injection mixed drug intratumoral to produce ROS and creating a coagulum as cancer therapeutics drug depot.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e15635-e15635
Author(s):  
Jian Zhang ◽  
Qiang Fu ◽  
Bian Li ◽  
Yan Han ◽  
Dong Chen ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Tumor Imaging ◽  
Cancer Therapeutics ◽  
Water Soluble ◽  
Control Group ◽  
Histological Structure ◽  
High Concentration ◽  
Long Time ◽  
Group 2 ◽  
Scanning Imaging

e15635 Background: To explore the nature of hydrogen peroxide at higher dosage for denature-aggregation of tumor with drugs through aggregation in denatured tumor as a coagulum for drug depot and prolong function of drug. Methods: (1). Preparation for two 5 ml of BLM-I131, one diluted with 0.12 ml NS and 0.2 ml (0.2mCi = 49.67µg BLM) for tumor injection in control group; one diluted with 0.12 ml of H2O2 (0.833 mg/ml) and 0.2 ml (0.2mCi = 49.67µg BLM) for tumor injection in experimental group. (2).Tumor imaging with BLM-I131 analyzed at different time points. (3). Radioactivity in tumor of mice analyzed under SPECT scanning imaging instrument at the 0, 5 h, 1 h, 2 h, 4 h, 8 h, 24 h, 48 h, 96 h, 120 h, 144 h and 168 h, activity of isotope I131 is representing the BLM retaining time in tumor. (4). Also, tumor sectioned and observed cellular and extracellular matrix changes of histological structure. Results: It was observed that BLM-I131 with ROS in tumors sustained for 168 hours while BLM-I131 with NS in tumors sustained for 8 hours only. Radioactivity of BLM-I131 in tumors with ROS reach at peak 1.5 hours and second peak at 20 hours by average to extend to 168 hours, while radioactivity of BLM-I131 in tumors with NS reached at peak in 0.5 hour, decreased to 30% in 1.5 hour quickly to background in 8 hours; We observed the extracellular matrix changes in experimental tumor while no changes in control tumor. Conclusions: A water soluble oxidant mixed with free drug can play a biological scissors role to chop tumor matrix, then it resulted in a denature tumor matrix into a coagulation for a drug depot, it showed drug of BLM-I131 sustained in tumor for a long time; while oxidant plays an important role to punch holes on cell membrane and resulted a high permeability for high concentration drug in each cancer cells.

scholarly journals Interactive Effects of Seasonal Temperature and Low pH on Resting Oxygen Uptake and Swimming Performance of Adult Brown Trout Salmo Trutta

1992 ◽  
Vol 165 (1) ◽  
pp. 195-212 ◽  
Author(s):  
P. J. BUTLER ◽  
N. DAY ◽  
K. NAMBA
Keyword(s):  
Oxygen Uptake ◽  
Brown Trout ◽  
Swimming Performance ◽  
Low Ph ◽  
Swimming Activity ◽  
Acid Water ◽  
Muscle Fibres ◽  
Seasonal Temperature ◽  
Neutral Ph ◽  
Red Muscle

Adult brown trout were acclimated for 2–4 weeks to artificial, soft water (Ca2+ 25μmoll−1) at neutral pH and at summer (15°C) or winter (5°C) temperatures. During this period they swam against a current of approximately 0.25 ms−1. They were then exposed to neutral or sublethal pH for 4 days in still water. For fish with their dorsal aorta catheterized, sublethal pH was 4 at 5°C and 4.5 at 15°C. After 4 days of exposure to sublethal pH, resting oxygen uptake (Mo2 w a s 40 % higher than that at neutral pH for fish held at 15°C and 38 % higher for fish held at 5°C. Critical swimming speeds (Ucrit), in contrast, were 35% and 31% lower, respectively. These two phenomena may be related in as much as the ‘metabolic cost’ of exposure to low pH may increase as swimming speed increases, thus reducing the scope for activity. Another important factor could be an impairment of oxygen delivery to the red muscle fibres. Although arterial O2 concentrations and heart rate are both similar for fish at Ucrit in neutral and acid water, there are signs of haemoconcentration in fish exposed to low pH, and the consequent increase in blood viscosity could disrupt the local circulation in the red fibres. Whatever its causes, an impairment of swimming activity resulting from exposure to acid water may have severe consequences for active fish such as salmonids. Exposure to sublethal pH caused significant reductions in plasma Na+ and Cl− concentrations at both temperatures, although these were more substantial at 5°C than at 15°C. Swimming at Ucrit had no significant effect on plasma concentrations of Na+, K+ and Cl− except at sublethal pH at 5°C, when there were significant reductions in all three. Seasonal temperature had significant but small effects on resting MO2 and Ucrit, and these are discussed in terms of the possible effects of low temperature and continued swimming activity (training) on hypertrophy of skeletal and cardiac muscles and on the aerobic capacity of the ‘red’ muscle fibres.

scholarly journals Numerical Simulation of Leakage and DiffusionProcess of LNG Storage Tanks

2021 ◽  
Author(s):  
Xue Li ◽  
Bing Chen ◽  
Vamegh Rasouli ◽  
Ning Zhou ◽  
Qian Zhang ◽  
...  
Keyword(s):  
Phase Change ◽  
Storage Tank ◽  
Methane Concentration ◽  
Gas Diffusion ◽  
Liquid Pool ◽  
High Concentration ◽  
Vapor Cloud ◽  
Long Time ◽  
Heavy Gas ◽  
Gas Cloud

Abstract Background The previous researches mainly focused on the potential hazards associated with LNG leaks and the level of the influence of external environmental factors on the dispersion effect of LNG spills. Few considerations were given to phase change. Therefore, in order to investigate the evolution process of LNG liquid pool and gas cloud diffusion, the effect of phase change on dispersion during LNG release is studied to analyze the behavior characteristics of LNG liquid pool expansion and gas cloud diffusion, and the effect of the leaking aperture on the gas cloud diffusion process is also studied. Methods The Eluerian model and Realizable k-ε model were used to numerically simulate the liquid phase leakage and diffusion process of LNG storage tanks. The homogeneous Eulerian multiphase model was adopted to model the phase change process after LNG leaks to the ground. The Eulerian model defines that different phases are treated as interpenetrating continuum, and each phase has its own conservation equation. The average diameter of LNG droplet and NG bubble were set to 0.01 m. The standard k-ε model and realizable k-ε model are commonly used to describe turbulent motion. However, the realizable k-ε model can not only effectively solve the problem of curved wall flow, but also simulate free flow containing jets and mixed flows. In addition, the realizable k-ε model had higher accuracy in concentration distribution by simulating Thorney’s heavy gas diffusion field test. Therefore, the realizable k-ε model was selected for gas diffusion turbulence. Results The diffusion of the explosive cloud was divided into heavy gas accumulation, entrainment heat transfer and light gas drift. The vapor cloud gradually separated into two parts from the whole "fan leaf shape". One part was a heavy gas cloud, the other part was a light gas cloud which spread with the wind in the downwind direction. The change of leakage aperture had a greater impact on the whole spill and dispersion process of the storage tank. The increasing leakage aperture would lead to 10.3 times increase in liquid pool area, 78.5% increase in downwind dispersion of methane concentration at 0.5LFL, 22.6% increase in crosswind dispersion of methane concentration at 0.5LFL and 249% increase in flammable vapor cloud volume. Within the variation range of the leakage aperture, the trend of the gas cloud diffusion remains consistent, but the time for the liquid pool to keep stable and the gas cloud to enter the next diffusion stage was delayed. The low-pressure cavity area within 200 m of the leeward surface of the storage tank will accumulate heavy gas for a long time, forming a local high concentration area. Conclusion Within the variation range of leakage aperture, there will always be a local high concentration area within 200 m downstream of the storage tank. In the field near the storage tank, the clouds settle and accumulate towards the ground in the state of gas-liquid two-phase flow, and the density of the cloud is gradually lower than the air in the far field, manifesting as light gas diffusion. The methane concentration in this area is high and lasts for a long time, so it should be the focus area of alarm prediction.

scholarly journals Influence of Pressing Temperature on Wood Properties

2022 ◽  
Author(s):  
M. Romanenko
Keyword(s):  
High Performance ◽  
Water Saturation ◽  
Wood Properties ◽  
Mechanical Action ◽  
Raw Material ◽  
Effect Of Temperature ◽  
Pressing Temperature ◽  
Long Time ◽  
Temperature And Pressure ◽  
Temperature Exposure

Abstract. Obtaining wood with high performance properties on the basis of chemical and mechanical action as a result of optimization of technological processes and the use of temperature exposure. The initial raw material is hardwood (aspen, alder), which are little used in construction and in the production of finishing materials. The condition for obtaining wood with high operating properties (increasing density, strength, reducing water saturation, ensuring the dimensional stability of samples for a long time) is the ability of wood as a natural polymer to change properties under the combined effect of temperature and pressure.

Uric acid distribution volume calculated by kinetic modeling and extracellular volume predicted by bioimpedance method

2020 ◽  
Vol 43 (11) ◽  
pp. 701-709
Author(s):  
Toru Shinzato ◽  
Shigeru Nakai ◽  
Takahito Ito ◽  
Kazuhiko Shibata ◽  
Teppei Matsuoka ◽  
...  
Keyword(s):  
Uric Acid ◽  
Mass Balance ◽  
Blood Test ◽  
Cell Membranes ◽  
Extracellular Volume ◽  
Distribution Volume ◽  
Facilitated Diffusion ◽  
Bioimpedance Analysis ◽  
Test Results ◽  
Simple Diffusion

Background: Several reports indicate that extracellular volume predicted by bioimpedance analysis method is associated with hydration status of hemodialysis patients. Theory: Fundamentally, uric acid does not cross cell membranes by simple diffusion, either by facilitated diffusion or by active transport. In addition, uric acid cannot move through cell membranes in most tissues other than those involved in uric acid excretion. These facts support the interpretation that uric acid distribution volume would therefore correlate with extracellular volume. Methods: We examined correlation between uric acid distribution volume calculated by uric acid mass-balance modeling from regular blood test results and extracellular volume predicted by bioimpedance analysis predicted by BCM (Fresenius Medical Care) in 53 patients. Results: There was a significant correlation between uric acid distribution volume ( x) and extracellular volume predicted by bioimpedance analysis ( y): y = 0.69 x + 3.39, r2 = 0.61, p < 0.0001. Bland–Altman analysis showed systematic error for uric acid distribution volume versus extracellular volume predicted by bioimpedance analysis (mean difference between uric acid distribution volume and extracellular volume predicted by bioimpedance analysis was 0.94 L, 95% confidence interval of difference was −3.29 to 5.17 L). Conclusion: Uric acid distribution volume calculated by uric acid mass-balance modeling from regular blood test results may be an alternative marker of extracellular volume predicted by bioimpedance analysis.

MITOCHONDRIAL ACTIVITY IN RAINBOW TROUT RED MUSCLE: THE EFFECT OF TEMPERATURE ON THE ADP-DEPENDENCE OF ATP SYNTHESIS

1993 ◽  
Vol 176 (1) ◽  
pp. 145-158 ◽  
Author(s):  
P. U. Blier ◽  
H. E. Guderley
Keyword(s):  
Rainbow Trout ◽  
Atp Synthesis ◽  
Effect Of Temperature ◽  
Mitochondrial Activity ◽  
Maximal Velocity ◽  
Atp Production ◽  
Constant Ph ◽  
Red Muscle ◽  
Increasing Temperature ◽  
Kinetics Of

By coupling mitochondrial ATP production to an enzymatic NADPH-producing reaction, we monitored the rates of ATP production spectrophotometrically. ATP production was coupled to the oxidation of malate and pyruvate. Interference by adenylate kinase was eliminated by using P1,P5- di(adenosine-5′)pentaphosphate and we found no interference by NADPH oxidase. We studied the kinetics of ATP synthesis by mitochondria from rainbow trout red muscle at three temperatures (8, 15 and 22 °C) and under two pH regimes (a constant pH of 7.4 and temperature-dependent pH). The mitochondria oxidized pyruvate and malate. The apparent Michaelis constant (Km,app) for ADP as well as the maximal velocity (Vmax) for ADP phosphorylation are markedly affected by temperature but not by pH. The Km,app for ADP decreases with increasing temperature while the Vmax increases. These data suggest that reduced temperatures decrease mitochondrial sensitivity to control by ADP availability.

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