Effect of temperature and stimulus train duration on the departure from theoretical maximum work in fish muscle

1994 ◽  
Vol 72 (6) ◽  
pp. 965-969 ◽  
Author(s):  
Eric A. Luiker ◽  
E. Don Stevens
Keyword(s):  
Duty Cycle ◽  
Relaxation Times ◽  
Length Change ◽  
Fish Muscle ◽  
Effect Of Temperature ◽  
Temperature Sensitive ◽  
Theoretical Maximum ◽  
Train Duration ◽  
Stimulus Train ◽  
Maximum Work

The goal of the present study was to compare the effect of temperature on contraction kinetic parameters of fish muscle with its effect on oscillatory work. In particular we studied the effect of stimulus train duration or duty cycle (the fraction of the imposed length change that the muscle was stimulated). We compared the actual work done by the muscle with a theoretical maximum work loop that would be achieved if it were fully and instantaneously relaxed at the onset of shortening and fully and instantaneously relaxed at the onset of lengthening. Temperature had a small effect on force but a marked effect on contraction and relaxation times. Thus, work was more temperature sensitive than force. The effect of temperature on work could not be predicted by its effect on any one contraction kinetic parameter. To achieve maximum work at lower temperatures, the duty cycle must be decreased because of the longer relaxation time.

Effect of stimulus train duration and cycle frequency on the capacity to do work in the pectoral fin muscle of the pumpkinseed sunfish, Lepomis gibbosus

1993 ◽  
Vol 71 (11) ◽  
pp. 2185-2189 ◽  
Author(s):  
Eric A. Luiker ◽  
E. Don Stevens
Keyword(s):  
Duty Cycle ◽  
Length Change ◽  
Lepomis Gibbosus ◽  
Pectoral Fin ◽  
Cycle Frequency ◽  
Pumpkinseed Sunfish ◽  
Train Duration ◽  
Stimulus Train ◽  
Length Changes ◽  
Time Required

The goal of our experiment was to elucidate the effect of stimulus duty cycle (the percentage of the cycle that the muscle was stimulated), phase (the relative timing of the imposed sinusoidal length change and stimulation), and muscle cycle frequency (the speed at which the muscle was cycled) on work and power in the pectoral fin muscle of a labriform swimmer, the pumpkinseed sunfish, Lepomis gibbosus. Stimulus train duration was varied from a twitch to a 40% duty cycle; cycle frequency was varied from 1 to 8 Hz. Work was calculated as the area of work loops produced by muscle contractions while the muscle was undergoing sinusoidal length changes. Maximum net work per cycle (6.2 J/kg) was produced at 1 Hz cycle frequency and a 32% duty cycle. Maximum power (26.7 W/kg) was produced at 5 Hz cycle frequency and a 16% duty cycle. As cycle frequency increased, the duty cycle and the stimulus train duration that produced maximum work decreased. The relatively long relaxation time compared with the length of time required to complete the whole cycle precluded the muscle from doing net positive work at high cycle frequencies.

Effect of stimulus frequency and duty cycle on force and work in fish muscle

1992 ◽  
Vol 70 (6) ◽  
pp. 1135-1139 ◽  
Author(s):  
Eric A. Luiker ◽  
E. Don Stevens
Keyword(s):  
Duty Cycle ◽  
Work Values ◽  
Stimulus Frequency ◽  
Fish Muscle ◽  
Adductor Muscle ◽  
Pulse Frequency ◽  
Pulse Number ◽  
Lepomis Gibbosus ◽  
Stimulus Pulse ◽  
Maximum Work

Stimulus trains of varying pulse number and pulse frequency were applied to the isolated pectoral adductor muscle of the sunfish Lepomis gibbosus. The number of pulses varied from 1 to 70, and the pulse frequency varied from 10 to 500 Hz. Muscle was continuously cycled at 2 Hz, and work was measured directly. Maximum force (177 kN/m2) was achieved with a train of 30 pulses at 169 Hz. Maximum work of 9.1 J/kg (power of 18.2 W/kg) was achieved with a train of 30 pulses at 169 Hz and a duty cycle (fraction of the cycle during which the muscle is activated) of 35%. Work values increased with an increase in the number of pulses per train, up to a maximum of 30 pulses. Duty cycle was the most important parameter in obtaining maximum work. The effect of varying stimulus pulse frequency on work values could not be accurately predicted from force values alone. For example, work increased 8-fold from twitch to maximum, whereas force increased only 2.6-fold.

scholarly journals Exploiting RNA thermometer-driven molecular bioprocess control as a concept for heterologous rhamnolipid production

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Philipp Noll ◽  
Chantal Treinen ◽  
Sven Müller ◽  
Lars Lilge ◽  
Rudolf Hausmann ◽  
...  
Keyword(s):  
High Titer ◽  
Production Capacity ◽  
Batch Process ◽  
Product Formation ◽  
Effect Of Temperature ◽  
Industrial Biotechnology ◽  
Temperature Sensitive ◽  
Translation Control ◽  
Rhamnolipid Production ◽  
Rna Thermometer

AbstractA key challenge to advance the efficiency of bioprocesses is the uncoupling of biomass from product formation, as biomass represents a by-product that is in most cases difficult to recycle efficiently. Using the example of rhamnolipid biosurfactants, a temperature-sensitive heterologous production system under translation control of a fourU RNA thermometer from Salmonella was established to allow separating phases of preferred growth from product formation. Rhamnolipids as bulk chemicals represent a model system for future processes of industrial biotechnology and are therefore tied to the efficiency requirements in competition with the chemical industry. Experimental data confirms function of the RNA thermometer and suggests a major effect of temperature on specific rhamnolipid production rates with an increase of the average production rate by a factor of 11 between 25 and 38 °C, while the major part of this increase is attributable to the regulatory effect of the RNA thermometer rather than an unspecific overall increase in bacterial metabolism. The production capacity of the developed temperature sensitive-system was evaluated in a simple batch process driven by a temperature switch. Product formation was evaluated by efficiency parameters and yields, confirming increased product formation rates and product-per-biomass yields compared to a high titer heterologous rhamnolipid production process from literature.

scholarly journals Theoretical Effect of Temperature on Threshold in the Hodgkin-Huxley Nerve Model

1966 ◽  
Vol 49 (5) ◽  
pp. 989-1005 ◽  
Author(s):  
Richard Fitzhugh
Keyword(s):  
Relaxation Time ◽  
Relaxation Times ◽  
Giant Axon ◽  
Temperature Curve ◽  
Effect Of Temperature ◽  
Threshold Temperature ◽  
Ionic Conductances ◽  
And Shifts ◽  
The Right ◽  
Increasing Temperature

In the squid giant axon, Sjodin and Mullins (1958), using 1 msec duration pulses, found a decrease of threshold with increasing temperature, while Guttman (1962), using 100 msec pulses, found an increase. Both results are qualitatively predicted by the Hodgkin-Huxley model. The threshold vs. temperature curve varies so much with the assumptions made regarding the temperature-dependence of the membrane ionic conductances that quantitative comparison between theory and experiment is not yet possible. For very short pulses, increasing temperature has two effects. (1) At lower temperatures the decrease of relaxation time of Na activation (m) relative to the electrical (RC) relaxation time favors excitation and decreases threshold. (2) For higher temperatures, effect (1) saturates, but the decreasing relaxation times of Na inactivation (h) and K activation (n) factor accommodation and increased threshold. The result is a U-shaped threshold temperature curve. R. Guttman has obtained such U-shaped curves for 50 µsec pulses. Assuming higher ionic conductances decreases the electrical relaxation time and shifts the curve to the right along the temperature axis. Making the conductances increase with temperature flattens the curve. Using very long pulses favors effect (2) over (1) and makes threshold increase monotonically with temperature.

scholarly journals Modelling tree ring cellulose <i>δ</i><sup>18</sup>O variations in two temperature-sensitive tree species from North and South America

2017 ◽  
Vol 13 (11) ◽  
pp. 1515-1526 ◽  
Author(s):  
Aliénor Lavergne ◽  
Fabio Gennaretti ◽  
Camille Risi ◽  
Valérie Daux ◽  
Etienne Boucher ◽  
...  
Keyword(s):  
South America ◽  
Isotopic Fractionation ◽  
Circulation Model ◽  
Effect Of Temperature ◽  
Temperature Sensitive ◽  
Nothofagus Pumilio ◽  
Climate Signal ◽  
North And South America ◽  
North And South ◽  
Two Temperature

Abstract. Oxygen isotopes in tree rings (δ18OTR) are widely used to reconstruct past climates. However, the complexity of climatic and biological processes controlling isotopic fractionation is not yet fully understood. Here, we use the MAIDENiso model to decipher the variability in δ18OTR of two temperature-sensitive species of relevant palaeoclimatological interest (Picea mariana and Nothofagus pumilio) and growing at cold high latitudes in North and South America. In this first modelling study on δ18OTR values in both northeastern Canada (53.86° N) and western Argentina (41.10° S), we specifically aim at (1) evaluating the predictive skill of MAIDENiso to simulate δ18OTR values, (2) identifying the physical processes controlling δ18OTR by mechanistic modelling and (3) defining the origin of the temperature signal recorded in the two species. Although the linear regression models used here to predict daily δ18O of precipitation (δ18OP) may need to be improved in the future, the resulting daily δ18OP values adequately reproduce observed (from weather stations) and simulated (by global circulation model) δ18OP series. The δ18OTR values of the two species are correctly simulated using the δ18OP estimation as MAIDENiso input, although some offset in mean δ18OTR levels is observed for the South American site. For both species, the variability in δ18OTR series is primarily linked to the effect of temperature on isotopic enrichment of the leaf water. We show that MAIDENiso is a powerful tool for investigating isotopic fractionation processes but that the lack of a denser isotope-enabled monitoring network recording oxygen fractionation in the soil–vegetation–atmosphere compartments limits our capacity to decipher the processes at play. This study proves that the eco-physiological modelling of δ18OTR values is necessary to interpret the recorded climate signal more reliably.

scholarly journals Understanding the effect of temperature on Bluetongue disease risk in livestock

2019 ◽  
Author(s):  
Fadoua El Moustaid ◽  
Zorian Thronton ◽  
Hani Slamani ◽  
Sadie J. Ryan ◽  
Leah R. Johnson
Keyword(s):  
Disease Risk ◽  
Vector Competence ◽  
Basic Reproductive Number ◽  
Effect Of Temperature ◽  
Reproductive Number ◽  
Temperature Sensitive ◽  
Modeling Tools ◽  
Vector Borne Diseases ◽  
Thermal Range ◽  
Vector Borne

AbstractThe transmission of vector-borne diseases is governed by complex factors including pathogen characteristics, vector-host interactions, and environmental conditions. Temperature is a major driver for many vector-borne diseases including Bluetongue viral (BTV) disease, a midge-borne febrile disease of ruminants, notably livestock, whose etiology ranges from mild or asymptomatic to rapidly fatal, thus threatening animal agriculture and the economy of affected countries. Using modeling tools, we seek to predict where transmission can occur based on suitable temperatures for BTV. We fit thermal performance curves to temperature sensitive midge life history traits, using a Bayesian approach. Then, we incorporated these into a new formula for the disease basic reproductive number, R0, to include trait responses, for two species of key midge vectors, Culicoides sonorensis and Culicoides variipennis. Our results show that outbreaks of BTV are more likely between 15°C and 33°C with predicted peak transmission at 26°C. The greatest uncertainty in R0 is associated with the uncertainty in: mortality and fecundity of midges near optimal temperature for transmission; midges’ probability of becoming infectious post infection at the lower edge of the thermal range; and the biting rate together with vector competence at the higher edge of the thermal range. We compare our R0 to two other R0 formulations and show that incorporating thermal curves into all three leads to similar BTV risk predictions. To demonstrate the utility of this model approach, we created global suitability maps indicating the areas at high and long-term risk of BTV transmission, to assess risk, and anticipate potential locations of establishment.

NQR Relaxation Studies on Halogenomethyl Groups in Halogenoacetates

1998 ◽  
Vol 53 (6-7) ◽  
pp. 480-483 ◽  
Author(s):  
Maria Zdanowska-Fnjczek
Keyword(s):  
Room Temperature ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Effect Of Temperature ◽  
Relaxation Theory ◽  
Temperature Range ◽  
Spin Lattice ◽  
Relaxation Studies

Abstract The effect of temperature on the chlorine NQR spin-lattice relaxation times in CsH(ClH2-CCOO)2 , KH(Cl3 CCOO) 2 and N(CH3)4 H(ClF2CCOO)2 has been studied in the temperature range 77 K to room temperature. The results were discussed on the basis of NQR relaxation theory.

scholarly journals The effect of temperature on differentSalmonellaserotypes during warm seasons in a Mediterranean climate city, Adelaide, Australia

2015 ◽  
Vol 144 (6) ◽  
pp. 1231-1240 ◽  
Author(s):  
A. MILAZZO ◽  
L. C. GILES ◽  
Y. ZHANG ◽  
A. P. KOEHLER ◽  
J. E. HILLER ◽  
...  
Keyword(s):  
Phage Type ◽  
Warm Season ◽  
Substantial Effect ◽  
Effect Of Temperature ◽  
Temperature Sensitive ◽  
Ambient Temperatures ◽  
Policy Interventions ◽  
Long Term Trends ◽  
Higher Temperature ◽  
The Impact

SUMMARYChanging trends in foodborne disease are influenced by many factors, including temperature. Globally and in Australia, warmer ambient temperatures are projected to rise if climate change continues.Salmonellaspp. are a temperature-sensitive pathogen and rising temperature can have a substantial effect on disease burden affecting human health. We examined the relationship between temperature andSalmonellaspp. and serotype notifications in Adelaide, Australia. Time-series Poisson regression models were fit to estimate the effect of temperature during warmer months onSalmonellaspp. and serotype cases notified from 1990 to 2012. Long-term trends, seasonality, autocorrelation and lagged effects were included in the statistical models. DailySalmonellaspp. counts increased by 1·3% [incidence rate ratio (IRR) 1·013, 95% confidence interval (CI) 1·008–1·019] per 1 °C rise in temperature in the warm season with greater increases observed in specific serotype and phage-type cases ranging from 3·4% (IRR 1·034, 95% CI 1·008–1·061) to 4·4% (IRR 1·044, 95% CI 1·024–1·064). We observed increased cases ofS. Typhimurium PT9 andS. Typhimurium PT108 notifications above a threshold of 39 °C. This study has identified the impact of warm season temperature on differentSalmonellaspp. strains and confirms higher temperature has a greater effect on phage-type notifications. The findings will contribute targeted information for public health policy interventions, including food safety programmes during warmer weather.

scholarly journals Insulin biosynthesis in the bullhead, Ictalurus nebulosus, and the effect of temperature

1973 ◽  
Vol 134 (3) ◽  
pp. 753-761 ◽  
Author(s):  
Margaret L. Moule ◽  
Cecil C. Yip
Keyword(s):  
Qualitative Difference ◽  
Gel Filtration ◽  
Effect Of Temperature ◽  
Insulin Biosynthesis ◽  
Temperature Sensitive ◽  
Bicarbonate Buffer ◽  
Control Tissue ◽  
Ictalurus Nebulosus ◽  
Lower Temperature

Insulin biosynthesis in the brown bullhead, Ictalurus nebulosus (Le Sueur), was studied by measuring the incorporation in vitro of [3H]leucine into proteins of the principal islet. The tissue was incubated for 6–15h in Krebs–Ringer bicarbonate buffer with [3H]leucine, supplemented with amino acids and glucose. Proteins, precipitated with trichloroacetic acid and extracted with acid ethanol, were separated by gel-filtration on Biogel P-30 in 3m-acetic acid. Three major components were found after incubation of the islets at 22°C. On the basis of the results of sulphitolysis, biological activity and the demonstrated precursor–product relationship, components I and II were identified as proinsulin and insulin respectively. The third component was not identified. At 12°C, [3H]leucine was incorporated only into proinsulin. No radioactivity was found in insulin or the unidentified component III at 12°C as was found after incubation at 22°C. When the temperature was lowered from 22° to 12°C after 3h of a 15h incubation, decreased conversion of proinsulin into insulin resulted at the lower temperature compared with the control tissue maintained at 22°C. When the temperature was raised from 12° to 22°C at 3h of a 15h incubation, conversion of proinsulin into insulin occurred. No conversion occurred in the control tissue with the temperature maintained at 12°C. No qualitative difference in the incorporation of [3H]leucine into proinsulin and its conversion into insulin at 12° and 22°C could be demonstrated between islet tissue from fish acclimated to less than 12°C or to 22°C. The results suggest that the enzyme(s) responsible for converting proinsulin into insulin in the bullhead may be temperature sensitive with low activity at 12°C.

Autonomic response to chronic electrode stimulation of cerebellum

1961 ◽  
Vol 201 (4) ◽  
pp. 697-699 ◽  
Author(s):  
J. D. Emerson ◽  
John M. Bruhn ◽  
Geraldine M. Emerson ◽  
J. O. Foley
Keyword(s):  
Autonomic Response ◽  
Bladder Pressure ◽  
P Values ◽  
Pupillary Dilatation ◽  
Pupillary Constriction ◽  
Train Duration ◽  
Stimulus Train ◽  
Steel Electrodes ◽  
Ansiform Lobule ◽  
Stimulation Of

The cerebellum was stimulated with implanted chronic concentric stainless steel electrodes in ten cats, with isolation of current to the cortex immediately beneath the electrodes. Stimulus parameters were: current density 0.5–2.55 ma/mm2, pulse duration 1–2 msec., frequency 100 cycle/sec, stimulus train duration 10–15 sec. Elevation of bladder pressure, pupillary dilatation, and pupillary constriction were obtained at P values of 10–7–10–10; depression of bladder pressure at P < 10–5. Responsive areas included ansiform lobule and vermis.

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