Quantifying Activation Rates of Scissile Mechanophores and the Influence of Dispersity

2021 ◽  
Author(s):  
Anna C. Overholts ◽  
Molly E. McFadden ◽  
Maxwell J. Robb
Keyword(s):  
Activation Rates

scholarly journals Fibre architecture and song activation rates of syringeal muscles are not lateralized in the European starling

2010 ◽  
Vol 213 (7) ◽  
pp. 1069-1078 ◽  
Author(s):  
A. M. Uchida ◽  
R. A. Meyers ◽  
B. G. Cooper ◽  
F. Goller
Keyword(s):  
European Starling ◽  
Activation Rates

A Review of Sufficient Schedulability Analysis for Fixed Priority Scheduling Systems

2015 ◽  
Vol 741 ◽  
pp. 856-859
Author(s):  
Yan Feng Zhai ◽  
Feng Xiang Zhang
Keyword(s):  
Schedulability Analysis ◽  
Priority Assignment ◽  
Priority Scheduling ◽  
Fixed Priority ◽  
Fixed Priority Scheduling ◽  
Rate Monotonic ◽  
Simple Implementation ◽  
Deadline Monotonic ◽  
Activation Rates

This papercarries out a survey of sufficient schedulability analysis forfixed priority (FP) scheduling. The most common used fixed priority assignment is the rate monotonic (RM) algorithm, according to its policy, the task priorities are ordered based on their activation rates, so that the task with the shortest period is assigned the highest priority. However, when each task’s relative deadline is not equal to its period, the RM algorithm is not suitable to assign the task priorities. When relative deadlines are less than or equal to periods,the deadline monotonic (DM) algorithm can be deployed to schedule the tasks. The utilization based schedulability analysis has the advantage of simple implementation, and manyexisting schedulability analyses on uniprocessor are covered.

scholarly journals Effects of regular exercise on ventricular myocyte biomechanics and KATP channel function

2018 ◽  
Vol 315 (4) ◽  
pp. H885-H896 ◽  
Author(s):  
Xinrui Wang ◽  
Robert H. Fitts
Keyword(s):  
Exercise Training ◽  
Left Ventricle ◽  
Current Density ◽  
Action Potential Duration ◽  
Adrenergic Receptor ◽  
Ventricular Myocyte ◽  
Regular Exercise ◽  
High Activation ◽  
Intracellular Ca ◽  
Activation Rates

Exercise training is known to protect the heart from ischemia and improve function during exercise by reducing cardiomyocyte action potential duration (APD) and increasing contractility. The cellular mechanisms involve β-adrenergic regulation and the ATP-sensitive K+ (KATP) channel, but how each alters function of the left ventricle and sex specificity is unknown. To address this, female and male Sprague-Dawley rats were randomly assigned to wheel-running (TRN) or sedentary (SED) groups. After 6–8 wk of training, myocytes were isolated from the left ventricle and field stimulated at 1, 2, and 5 Hz. TRN significantly increased cardiomyocyte contractility, the kinetics of the Ca2+ transient, and responsiveness to the adrenergic receptor agonist isoproterenol (ISO), as reflected by an increased sarcomere shortening. Importantly, we demonstrated a TRN-induced upregulation of KATP channels, which was reflected by elevated content, current density, and the channel’s contribution to APD shortening at high activation rates and in the presence of the activator pinacidil. TRN induced increase in KATP current occurred throughout the left ventricle, but channel subunit content showed regional specificity with increases in Kir6.2 in the apex and SUR2A in base regions. In summary, TRN elevated cardiomyocyte cross-bridge kinetics, Ca2+ sensitivity, and the responsiveness of contractile function to β-adrenergic receptor stimulation in both sexes. Importantly, upregulation of the KATP channel accelerates repolarization and shortens APD during stress and exercise. These adaptations have clinical importance, as increased contractility and reduced APD would help protect cardiac output and reduce intracellular Ca2+ overload during stresses such as regional ischemia. NEW & NOTEWORTHY Our results demonstrate that regular exercise significantly increased ventricular myocyte shortening and relaxation velocity and the rate of rise in intracellular Ca2+ transient and enhanced the response of biomechanics and Ca2+ reuptake to β-adrenergic stimulation. Importantly, exercise training upregulated the cardiomyocyte sarcolemma ATP-sensitive K+ channel across the left ventricle in both sexes, as reflected by elevated channel subunit content, current density, and the channel’s contribution to reduced action potential duration at high activation rates.

Comparison of activation ability between feline and bovine oocytes

2013 ◽  
Vol 61 (4) ◽  
pp. 491-494 ◽  
Author(s):  
Fuminori Tanihara ◽  
Yukine Kaedei ◽  
Zhao Namula ◽  
Vien Luu ◽  
Yoko Sato ◽  
...  
Keyword(s):  
Chemical Treatment ◽  
Mammalian Species ◽  
Parthenogenetic Activation ◽  
Activation Rates ◽  
Bovine Oocytes ◽  
Higher Sensitivity

Research comparing the activation sensitivity of oocytes to chemical treatment among mammalian species remains limited. We compared the activation ability of oocytes from bovine and feline ovaries when treated with ethanol alone, with ethanol and cycloheximide, and without any chemical treatment; the oocytes were then cultured for 72 h. After in vitro maturation (IVM), 5% of feline oocytes were activated and 1% were cleaved, whereas there were no prematurely activated bovine oocytes. Activation rates with ethanol and ethanol/cycloheximide were significantly higher (P < 0.01) in bovine oocytes than in feline oocytes (74.2% vs. 34.1% and 86.3% vs. 52.5%, respectively). Thus, our findings indicate that feline oocytes can be prematurely activated by the end of IVM, and that bovine oocytes may have a higher sensitivity of parthenogenetic activation to chemical treatment than do feline oocytes.

Variant Plasminogens in Patients with a History of Venous Thrombosis

1979 ◽  
Author(s):  
K.C. Robbins ◽  
R.C. Wohl ◽  
L. Summaria
Keyword(s):  
Venous Thrombosis ◽  
Rate Constants ◽  
Autosomal Dominant ◽  
Binding Properties ◽  
Activation Data ◽  
History Of ◽  
Michaelis Constants ◽  
Catalytic Rate ◽  
Abnormal Plasminogen ◽  
Activation Rates

Kinetic methods will be described For measuring plasminogen and for studying plasminoge activation in human plasma, using specific synthetic substrates, with different activat, species. These studies resulted in the discovery of several patients plasmas containin-variant, or abnormal, plasminogen molecules; these plasmas showed lower observable activation rates. Plasminogen isolated from these plasmas activated with Identical catalytic rate constants to normal plasminogen, by different activator species, but the apparent Michaelis constants were 10- to 100-fold higher. These data lead to the conclsion that the binding properties of the activator species to the variant plasminogens have been impaired. The interpretation of the data In two patients with venous thrpto-sis was possible only in terms of homogeneous populations of plasminogen molecules. These individuals have to be considered homozygous with respect to their plasminogens, and Family studies Indicate the possibility of an autosomal dominant hereditary transmission. The urokinase activation data with the variant plasminogens point to an activation mechanisn identical to that proposed for streptokinase, namely the activation of Plasminogen hy a plasminogen-urokinase complex, analogous with the plasminogen-streptokinase comnlex.

Gradation of isometric tension by different activation rates in motor units of cat flexor carpi radialis muscle

1986 ◽  
Vol 56 (2) ◽  
pp. 494-506 ◽  
Author(s):  
B. R. Botterman ◽  
G. A. Iwamoto ◽  
W. J. Gonyea
Keyword(s):  
Muscle Tension ◽  
Motor Units ◽  
Isometric Tension ◽  
Medial Gastrocnemius ◽  
Potential Contribution ◽  
Tension Development ◽  
Stimulus Interval ◽  
Flexor Carpi Radialis ◽  
Single Motor Units ◽  
Activation Rates

Single motor units of the flexor carpi radialis (FCR) muscle were activated with a series of constant-rate stimulus trains to study the relation between the frequency of activation and isometric tension development (F-T relation). The tension produced by each stimulus train was expressed as a percentage of the maximum tension-time area (Amax) found for a given unit. Between 25 and 75% Amax a clear separation was seen in the rates needed to produce the same relative tension for the F-T curves of slow-twitch (type S) and fast-twitch (type F) units. Over the steepest portion of the F-T curve (25-50% Amax), where tension output was most sensitive to changes in activation rate, type F units required substantially higher stimulation rates (30 pps) to achieve the same relative tension output as type S units. Furthermore, the frequency range that corresponded to the steep portion of the curve was 2.3 times greater for type F units. For both type S and F units, twitch duration was deemed to be an important determinant of the F-T curve, as has been shown previously. A direct continuous relation was seen between the integrated twitch time (ITT) and the stimulus interval needed to produce 50% Amax (r = 0.94, P less than 0.001). Thus, units that had relatively brief twitches required higher activation rates to achieve the same relative percentage of Amax. Comparison of F-T curves from FCR with those derived by other investigators for cat hindlimb units (medial gastrocnemius and peroneus longus) revealed that significant differences in activation rates were needed to produce the same percentage of Amax throughout the midrange of the F-T curve. At 50% Amax, type F units in FCR required activation rates approximately 20 pps higher than type F units in the hindlimb. Type S units in FCR required only slightly higher rates (approximately equal to 5 pps). Based on a number of well-founded assumptions, F-T curves derived from FCR units were used to estimate the potential contribution of rate coding to total muscle tension by type S and F units. This analysis leads to the conclusion that rate modulation is a potentially important factor in the gradation of tension for the FCR muscle.

scholarly journals Analysis of stochastic timing of intracellular events with gene switching

2019 ◽  
Author(s):  
Khem Raj Ghusinga ◽  
Abhyudai Singh
Keyword(s):  
First Passage Time ◽  
Regulatory Protein ◽  
Gene Activation ◽  
Threshold Level ◽  
Passage Time ◽  
First Passage ◽  
Cellular Processes ◽  
Event Timing ◽  
Activation Rates ◽  
Gene Switching

AbstractAn important step in execution of several cellular processes is accumulation of a regulatory protein up to a specific threshold level. Since production of a protein is inherently stochastic, the time at which its level crosses a threshold exhibits cell-to-cell variation. A problem of interest is to characterize how the statistics of event timing is affected by various steps of protein expression. Our previous work studied this problem by considering a gene expression model where gene was always active. Here we extend our analysis to a scenario where gene stochastically switches between active and inactive states. We formulate event timing as the first-passage time for a protein’s level to cross a threshold and investigate how the rates of gene activation/inactivation affect the distribution and moments of the first-passage time. Our results show that both the time-scale of gene switching with respect to the protein degradation rate as well as the ratio of the gene inactivation to gene activation rates are important parameters in shaping the event-timing distribution.

scholarly journals Improvement in geriatric trauma outcomes in an evolving trauma system

2019 ◽  
Vol 4 (1) ◽  
pp. e000282 ◽  
Author(s):  
Amund Hovengen Ringen ◽  
Iver Anders Gaski ◽  
Hege Rustad ◽  
Nils Oddvar Skaga ◽  
Christine Gaarder ◽  
...  
Keyword(s):  
Trauma System ◽  
Trauma Team ◽  
The Elderly ◽  
Geriatric Trauma ◽  
Trauma Patients ◽  
Age Group ◽  
Trauma Team Activation ◽  
Activation Rate ◽  
Time Periods ◽  
Activation Rates

BackgroundThe elderly trauma patient has increased mortality compared with younger patients. During the last 15 years, initial treatment of severely injured patients at Oslo University Hospital Ulleval (OUHU) has changed resulting in overall improved outcomes. Whether this holds true for the elderly trauma population needs exploration and was the aim of the present study.MethodsWe performed a retrospective study of 2628 trauma patients 61 years or older admitted to OUHU during the 12-year period, 2002–2013. The population was stratified based on age (61–70 years, 71–80 years, 81 years and older) and divided into time periods: 2002–2009 (P1) and 2010–2013 (P2). Multiple logistic regression models were constructed to identify clinically relevant core variables correlated with mortality and trauma team activation rate.ResultsCrude mortality decreased from 19% in P1 to 13% in P2 (p<0.01) with an OR of 0.77 (95 %CI 0.65 to 0.91) when admitted in P2. Trauma team activation rates increased from 53% in P1 to 72% in P2 (p<0.01) with an OR of 2.16 (95% CI 1.93 to 2.41) for being met by a trauma team in P2. Mortality increased from 10% in the age group 61–70 years to 26% in the group above 80 years. Trauma team activation rates decreased from 71% in the age group 61–70 years to 50% in the age group older than 80 years. Median ISS were 17 in all three age groups and in both time periods.DiscussionDevelopment of a multidisciplinary dedicated trauma service is associated with increased trauma team activation rate as well as survival in geriatric trauma patients. As expected, mortality increased with age, although inversely related to the likelihood of being met by a trauma team. Trauma team activation should be considered for all trauma patients older than 70 years.Level of evidenceLevel IV.

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