scholarly journals Modelling the spatial and temporal constrains of the GABAergic influence on neuronal excitability

2021 ◽  
Vol 17 (11) ◽  
pp. e1009199
Author(s):  
Aniello Lombardi ◽  
Heiko J. Luhmann ◽  
Werner Kilb
Keyword(s):  
Neuronal Excitability ◽  
Reversal Potential ◽  
Adult Brain ◽  
Minor Effect ◽  
Spatial Dependency ◽  
Excitatory Effect ◽  
Inhibitory Neurotransmitter ◽  
Wide Range ◽  
A Minor ◽  
The Impact

GABA (γ-amino butyric acid) is an inhibitory neurotransmitter in the adult brain that can mediate depolarizing responses during development or after neuropathological insults. Under which conditions GABAergic membrane depolarizations are sufficient to impose excitatory effects is hard to predict, as shunting inhibition and GABAergic effects on spatiotemporal filtering of excitatory inputs must be considered. To evaluate at which reversal potential a net excitatory effect was imposed by GABA (EGABAThr), we performed a detailed in-silico study using simple neuronal topologies and distinct spatiotemporal relations between GABAergic and glutamatergic inputs. These simulations revealed for GABAergic synapses located at the soma an EGABAThr close to action potential threshold (EAPThr), while with increasing dendritic distance EGABAThr shifted to positive values. The impact of GABA on AMPA-mediated inputs revealed a complex temporal and spatial dependency. EGABAThr depends on the temporal relation between GABA and AMPA inputs, with a striking negative shift in EGABAThr for AMPA inputs appearing after the GABA input. The spatial dependency between GABA and AMPA inputs revealed a complex profile, with EGABAThr being shifted to values negative to EAPThr for AMPA synapses located proximally to the GABA input, while for distally located AMPA synapses the dendritic distance had only a minor effect on EGABAThr. For tonic GABAergic conductances EGABAThr was negative to EAPThr over a wide range of gGABAtonic values. In summary, these results demonstrate that for several physiologically relevant situations EGABAThr is negative to EAPThr, suggesting that depolarizing GABAergic responses can mediate excitatory effects even if EGABA did not reach EAPThr.

scholarly journals Modelling the spatial and temporal constrains of the GABAergic influence on neuronal excitability

2021 ◽  
Author(s):  
Aniello Lombardi ◽  
Heiko J Luhmann ◽  
Werner Kilb
Keyword(s):  
Neuronal Excitability ◽  
Reversal Potential ◽  
Adult Brain ◽  
Minor Effect ◽  
Spatial Dependency ◽  
Excitatory Effect ◽  
Inhibitory Neurotransmitter ◽  
Wide Range ◽  
A Minor ◽  
The Impact

GABA (γ-amino butyric acid) is an inhibitory neurotransmitter in the adult brain that can mediate depolarizing responses during development or after neuropathological insults. Under which conditions GABAergic membrane depolarizations are sufficient to impose excitatory effects is hard to predict, as shunting inhibition and GABAergic effects on spatiotemporal filtering of excitatory inputs must be considered. To evaluate at which reversal potential a net excitatory effect was imposed by GABA (EGABAThr), we performed a detailed in-silico study using simple neuronal topologies and distinct spatiotemporal relations between GABAergic and glutamatergic inputs. These simulations revealed for GABAergic synapses located at the soma an EGABAThr close to action potential threshold (EAPThr), while with increasing dendritic distance EGABAThr shifted to positive values. The impact of GABA on AMPA-mediated inputs revealed a complex temporal and spatial dependency. EGABAThr depends on the temporal relation between GABA and AMPA inputs, with a striking negative shift in EGABAThr for AMPA inputs appearing after the GABA input. The spatial dependency between GABA and AMPA inputs revealed a complex profile, with EGABAThr being shifted to values negative to EAPThr for AMPA synapses located proximally to the GABA input, while for distally located AMPA synapses the dendritic distance had only a minor effect on EGABAThr. For tonic GABAergic conductances EGABAThr was negative to EAPThr over a wide range of gGABAtonic values. In summary, these results demonstrate that for several physiologically relevant situations EGABAThr is negative to EAPThr, suggesting that depolarizing GABAergic responses can mediate excitatory effects even if EGABA did not reach EAPThr.

scholarly journals Influences of shrinkage reducing admixture on the mechanical properties, drying shrinkage, water absorption and porosity of Portland cement mortar

2021 ◽  
Vol 15 (3) ◽  
pp. 55-67
Author(s):  
Nguyen Van Chinh
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Portland Cement ◽  
Water Absorption ◽  
Drying Shrinkage ◽  
Effective Porosity ◽  
Minor Effect ◽  
Wide Range ◽  
Shrinkage Reducing Admixture ◽  
A Minor

Drying shrinkage is the main cause of early age cracking of concrete and mortar. A wide range of research has been conducted to reduce the drying shrinkage, including using fibres or chemical admixtures. This paper investigated the effect of shrinkage reducing admixture on the flexural strength, compressive strength, drying shrinkage, water absorption and porosity of mortar. The mix compositions were ordinary Portland cement (OPC) : sand : liquid = 1: 1: 0.38 in which liquid consisted of water and shrinkage reducing admixture (SRA). SRA was used at the proportions of 2%, 4%, and 7% by weight of cement. The test results show that SRA reduces the flexural and compressive strengths of mortar. The reduction in flexural strength and compressive strength at 28 days is 14% and 25%, respectively at 7% SRA dosage. In addition, SRA significantly reduces the drying shrinkage and water absorption of mortar. At 7% SRA dosage, the drying shrinkage at 53 days is reduced by 60% while the water absorption rate at 24 hours is reduced by 54%. However, SRA has a minor effect on the pore size distribution, effective porosity, and cumulative intrusion volume of mortar.

Isothermal Physical Flow Modeling of a Gas Turbine Simple-Cycle Selective-Catalytic-Reduction (SCR) System

2013 ◽  
Author(s):  
Larry Swanson ◽  
Hua Zhang ◽  
Doug Byrd
Keyword(s):  
Selective Catalytic Reduction ◽  
Gas Turbine ◽  
Catalytic Reduction ◽  
Transport Processes ◽  
Simple Cycle ◽  
Minor Effect ◽  
Tracer Injection ◽  
A Minor ◽  
Scr System ◽  
The Impact

A physical flow model of a gas turbine (GT) simple-cycle Selective-Catalytic-Reduction (SCR) system was constructed to a 1/16 geometric scale to validate computational fluid dynamics (CFD) predictions and examine the impact of tempering air injection on system performance. Repeatable velocity contours and tempering air dispersion profiles were developed for baseline (no tempering air), and 12- and 6-lance tempering air injector configurations. The conclusions from the study are: (1) relative to the no lance baseline case, the 12-lance configuration tends to force more of the inlet flow towards the top of the duct, whereas the 6-lance configuration does not affect the upstream profile significantly, (2) adding tempering air does not have a significant impact on the diffuser inlet velocity distribution and has a minor effect on the velocity and dispersion profiles at the NOX-catalyst inlet, (3) at the NOX-catalyst inlet, the 6-lance configuration with tempering air exhibits a slightly skewed flow toward the lower right corner of the duct with a coefficient of variation (COV) of 19.4%, which is slightly better than that for the 12-lance configuration, (4) at the NOX-catalyst inlet, the 12-lance configuration disperses tempering air best because its COV is 20.8% relative to a 27.3% COV for the 6-lance configuration, and (5) a comparison between the local mixing-cup temperature contours for both 12- and 6-lance configurations, based on tracer injection into the tempering air flow, confirms that the CFD model does a good job of qualitatively predicting the heat and mass transport processes in the GT simple-cycle SCR system.

scholarly journals Are suggestions from coupled file changes useful for perfective maintenance tasks?

2017 ◽  
Vol 3 ◽  
pp. e135 ◽  
Author(s):  
Jasmin Ramadani ◽  
Stefan Wagner
Keyword(s):  
Software Maintenance ◽  
Tracking System ◽  
Minor Effect ◽  
New Members ◽  
Team Members ◽  
Using Data ◽  
Time Required ◽  
A Minor ◽  
The Impact ◽  
Important Activity

Background Software maintenance is an important activity in the development process where maintenance team members leave and new members join over time. The identification of files which are changed together frequently has been proposed several times. Yet, existing studies about coupled file changes ignore the feedback from developers as well as the impact of these changes on the performance of maintenance and rather these studies rely on the analysis findings and expert evaluation. Methods We investigate the usefulness of coupled file changes during perfective maintenance tasks when developers are inexperienced in programming or when they were new on the project. Using data mining on software repositories we identify files that are changed most frequently together in the past. We extract coupled file changes from the Git repository of a Java software system and join them with corresponding attributes from the versioning and issue tracking system and the project documentation. We present a controlled experiment involving 36 student participants in which we investigate if coupled file change suggestions influence the correctness of the task solutions and the required time to complete them. Results The results show that the use of coupled file change suggestions significantly increases the correctness of the solutions. However, there is only a minor effect on the time required to complete the perfective maintenance tasks. We also derived a set of the most useful attributes based on the developers’ feedback. Discussion Coupled file changes and a limited number of the proposed attributes are useful for inexperienced developers working on perfective maintenance tasks where although the developers using these suggestions solved more tasks, they still need time to understand and organize this information.

scholarly journals Parasitism may enhance rather than reduce the predatory impact of an invader

2010 ◽  
Vol 6 (5) ◽  
pp. 636-638 ◽  
Author(s):  
Jaimie T. A. Dick ◽  
Michael Armstrong ◽  
Hazel C. Clarke ◽  
Keith D. Farnsworth ◽  
Melanie J. Hatcher ◽  
...  
Keyword(s):  
Parasite Prevalence ◽  
Reproductive Period ◽  
Enemy Release ◽  
Minor Effect ◽  
Host Feeding ◽  
Feeding Rates ◽  
Functional Responses ◽  
Predatory Impact ◽  
A Minor ◽  
The Impact

Invasive species can have profound impacts on communities and it is increasingly recognized that such effects may be mediated by parasitism. The ‘enemy release’ hypothesis posits that invaders may be successful and have high impacts owing to escape from parasitism. Alternatively, we hypothesize that parasites may increase host feeding rates and hence parasitized invaders may have increased community impacts. Here, we investigate the influence of parasitism on the predatory impact of the invasive freshwater amphipod Gammarus pulex . Up to 70 per cent of individuals are infected with the acanthocephalan parasite Echinorhynchus truttae , but parasitized individuals were no different in body condition to those unparasitized. Parasitized individuals consumed significantly more prey ( Asellus aquaticus ; Isopoda) than did unparasitized individuals. Both parasitized and unparasitized individuals displayed Type-II functional responses (FRs), with the FR for parasitized individuals rising more steeply, with a higher asymptote, compared with unparasitized individuals. While the parasite reduced the fitness of individual females, we predict a minor effect on population recruitment because of low parasite prevalence in the peak reproductive period. The parasite thus has a large per capita effect on predatory rate but a low population fitness effect, and thus may enhance rather than reduce the impact of this invader.

Cohesive Zone Modeling of Stable Crack Propagation in Highly Ductile Steel

2018 ◽  
Vol 774 ◽  
pp. 167-172 ◽  
Author(s):  
Andreas Burgold ◽  
Stephan Roth ◽  
Meinhard Kuna
Keyword(s):  
Cohesive Zone ◽  
Large Scale ◽  
Cohesive Zone Model ◽  
Cohesive Zone Modeling ◽  
Zone Model ◽  
Minor Effect ◽  
Stable Crack Propagation ◽  
Wide Range ◽  
Separation Relation ◽  
A Minor

A recent cohesive zone model is applied to the simulation of crack extension in austenitic stainless steel under large scale yielding conditions. The shape of the corresponding exponential traction-separation-relation can be modified in a wide range. In order to investigate the sensitivity regarding the cohesive zone parameters, a systematic parametric study is performed. The shape of the traction-separation envelope has a minor effect on the results compared to the cohesive strength and the work of separation. The aim is to fit experimental data by an appropriate choice of these parameters. Therefore, not only force-displacement curves should be used, but also crack growth resistance curves should be employed. A promising strategy for parameter identification is derived.

scholarly journals Differential effects of corticosteroids and anti-TNF on tumor-specific immune responses - implications for the management of irAEs

2018 ◽  
Author(s):  
Arianna Draghi ◽  
Troels Holz Borch ◽  
Haja Dominike Radic ◽  
Christopher Aled Chamberlain ◽  
Aishwarya Gokuldass ◽  
...  
Keyword(s):  
T Cell Activation ◽  
Cell Activation ◽  
Tumor Infiltrating Lymphocytes ◽  
High Dose ◽  
Minor Effect ◽  
Tumor Killing ◽  
High Doses ◽  
A Minor ◽  
The Impact

AbstractUp to 60% of patients treated with cancer immunotherapy develop severe or life threatening immune-related adverse events (irAEs). Immunosuppression with high doses of corticosteroids or, in refractory cases, with tumor necrosis factor (TNF) antagonists, are the mainstay of treatment for irAEs. It is currently unknown what is the impact of corticosteroids and anti-TNF on the activity of antitumor T cells. In this study, the influences of clinically relevant doses of dexamethasone (corresponding to an oral dose of 10 to 125 mg prednisolone) and infliximab (anti-TNF) on the activation and killing ability of tumor-infiltrating lymphocytes (TILs) was tested in vitro. Overall, dexamethasone at low or intermediate/high dose impaired the activation (respectively −46% and −62%) and tumor-killing ability (respectively −48% and −53%) of tumor-specific TILs. In contrast, a standard clinical dose of infliximab only had a minor effect on T cell activation (−20%) and tumor killing (−10%). A brief resting following exposure to dexamethasone was sufficient to rescue the in vitro activity of TILs. In conclusion, clinically-relevant doses of infliximab only influenced to a lesser extent the activity of tumor-specific TILs in vitro, whereas even low doses of corticosteroids markedly impaired the antitumor activity of TILs. These data support steroid-sparing strategies and early initiation of anti-TNF for the treatment of irAEs in immuno-oncology.

A Discussion of Iron Golf Club Head Inertia Tensors and Their Effects on the Golfer

1996 ◽  
Vol 12 (4) ◽  
pp. 449-469 ◽  
Author(s):  
Steven M. Nesbit ◽  
Terry A. Hartzell ◽  
John C. Nalevanko ◽  
Ryan M. Starr ◽  
Mathew G. White ◽  
...  
Keyword(s):  
Major Effect ◽  
Golf Swing ◽  
Golf Club ◽  
Minor Effect ◽  
Impact Function ◽  
Club Head ◽  
A Minor ◽  
The Impact ◽  
Flexible Model ◽  
Eccentric Impact

This paper discusses the inertia tensors of iron golf club heads and their influence on the swing of a golfer and the behavior of the golf club. Inertia tensors of various five-iron club head configurations were determined using solid modeling and were compared with equivalent solid ellipsoids. A golf swing and club behavior analysis was performed using a computer model comprised of a 3D parametric flexible model of a golf club driven with data from a recorded golf swing, and an impact function. The impact results were verified experimentally. The analysis without impact determined that altering club head inertia had a minor effect on the torque required to swing the club and the deflections of the club head at the time of impact. The analysis with an eccentric impact found that altering club head inertia had a major effect on transmitted forces and torques and a moderate effect on deflection of the club head.

The Outcomes of Student Protest

2020 ◽  
pp. 129-170
Author(s):  
Donatella della Porta ◽  
Lorenzo Cini ◽  
César Guzmán-Concha
Keyword(s):  
Trade Unions ◽  
Minor Effect ◽  
Education Policies ◽  
Student Protests ◽  
Political Actors ◽  
Higher Education Policies ◽  
The Government ◽  
A Minor ◽  
Student Demands ◽  
The Impact

This chapter evaluates the impact of student protests in the four regions on higher education policies. The four cases differ in the degree to which students were able to achieve concessions close to their demands. In both Chile and Quebec, as student demands were supported by significant social constituencies and the government proved unable to appease the protests, the opposition parties presented themselves as allies. These parties committed themselves to delivering reforms that would (partially) meet student demands, while students attempted to gain influence in decision-making bodies by joining political parties and/or participating in elections. By contrast, in England and Italy, students did not obtain concessions from the government, while their campaigns had a minor effect on public opinion, which remained relatively indifferent to their demands. More notably, student protesters failed to build solid alliances with other social and political actors opposing similar neoliberal measures in other fields of policy, such as trade unions, radical left parties, and social movements.

What causes financial crisis in Asian countries?

2018 ◽  
pp. 5-19 ◽  
Author(s):  
Anh Thi Thuy Vo ◽  
Thuy Xuan Ha ◽  
Khanh Phan Nha Bui
Keyword(s):  
Corporate Governance ◽  
Financial Crisis ◽  
Minor Effect ◽  
Asian Countries ◽  
Macroeconomic Factors ◽  
Governance Index ◽  
The Business Cycle ◽  
A Minor ◽  
And Control ◽  
The Impact

In this paper, we investigate the indicators of financial crisis in Asian countries, focusing more on the impact of corporate governance. Unlike the previous studies such as Johnson et al. (2000) and Acemoglu et al. (2003) that use some fixed measures of corporate governance based on the law in force in a specific year—such as the anti-director right index (ADRI) or the anti-self dealing index (ASDI)—we employ the annual Worldwide Governance Index (WGIs) and the Quality of Governance Index. The regression results, which use the data of 19 Asian countries from 1996 to 2015, and control for country fixed effect and the business cycle, show that the macroeconomic factors appear to have no effect, or a minor effect, on currency depreciation. However, better corporate governance reduces the decline in currency value.

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