scholarly journals Simulation and modeling of physiological processes of vital organs in organ-on-a-chip biosystem

2021 ◽  
pp. 101710
Author(s):  
Sadegh Seidi ◽  
Aziz Eftekhari ◽  
Ameer Khusro ◽  
Reza Shiri Heris ◽  
Muhammad Umar Khayam Sahibzada ◽  
...  
Keyword(s):  
Simulation And Modeling ◽  
Physiological Processes ◽  
Organ On A Chip

Localization of Adenosine Triphosphatase Activity in the Phleom of Nicotiana Tabacum

1972 ◽  
Vol 30 ◽  
pp. 230-231
Author(s):  
James Cronshaw ◽  
Jamison E. Gilder
Keyword(s):  
Plasma Membrane ◽  
Atpase Activity ◽  
Adenosine Triphosphatase ◽  
Higher Plants ◽  
High Surface ◽  
Root Tip ◽  
Animal Cells ◽  
Physiological Processes ◽  
Tip Cells ◽  
Atpase Localization

Adenosine triphosphatase (ATPase) activity has been shown to be associated with numerous physiological processes in both plants and animal cells. Biochemical studies have shown that in higher plants ATPase activity is high in cell wall preparations and is associated with the plasma membrane, nuclei, mitochondria, chloroplasts and lysosomes. However, there have been only a few ATPase localization studies of higher plants at the electron microscope level. Poux (1967) demonstrated ATPase activity associated with most cellular organelles in the protoderm cells of Cucumis roots. Hall (1971) has demonstrated ATPase activity in root tip cells of Zea mays. There was high surface activity largely associated with the plasma membrane and plasmodesmata. ATPase activity was also demonstrated in mitochondria, dictyosomes, endoplasmic reticulum and plastids.

A Scanning Electron Microscopic Study of Pro-Vascular Cellular Morphology in Chaetophora Incressata

1985 ◽  
Vol 43 ◽  
pp. 638-639
Author(s):  
A. E. Hotchkiss ◽  
A. T. Hotchkiss ◽  
R. P. Apkarian
Keyword(s):  
Green Algae ◽  
Vascular Plants ◽  
Vascular System ◽  
Higher Plants ◽  
Wall Structure ◽  
Electron Microscopic ◽  
Physiological Processes ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

Multicellular green algae may be an ancestral form of the vascular plants. These algae exhibit cell wall structure, chlorophyll pigmentation, and physiological processes similar to those of higher plants. The presence of a vascular system which provides water, minerals, and nutrients to remote tissues in higher plants was believed unnecessary for the algae. Among the green algae, the Chaetophorales are complex highly branched forms that might require some means of nutrient transport. The Chaetophorales do possess apical meristematic groups of cells that have growth orientations suggestive of stem and root positions. Branches of Chaetophora incressata were examined by the scanning electron microscope (SEM) for ultrastructural evidence of pro-vascular transport.

Nonlinear Circuit Simulation and Modeling

2018 ◽  
Author(s):  
José Carlos Pedro ◽  
David E. Root ◽  
Jianjun Xu ◽  
Luís Cótimos Nunes
Keyword(s):  
Circuit Simulation ◽  
Simulation And Modeling ◽  
Nonlinear Circuit

Ambulatory Assessment

2009 ◽  
Vol 14 (2) ◽  
pp. 109-119 ◽  
Author(s):  
Ulrich W. Ebner-Priemer ◽  
Timothy J. Trull
Keyword(s):  
Real Time ◽  
Clinical Psychology ◽  
Real Life ◽  
Ambulatory Assessment ◽  
Computer Assisted ◽  
Affective Valence ◽  
Time Data ◽  
Physiological Processes ◽  
Context Specific ◽  
Questionnaire Studies

Convergent experimental data, autobiographical studies, and investigations on daily life have all demonstrated that gathering information retrospectively is a highly dubious methodology. Retrospection is subject to multiple systematic distortions (i.e., affective valence effect, mood congruent memory effect, duration neglect; peak end rule) as it is based on (often biased) storage and recollection of memories of the original experience or the behavior that are of interest. The method of choice to circumvent these biases is the use of electronic diaries to collect self-reported symptoms, behaviors, or physiological processes in real time. Different terms have been used for this kind of methodology: ambulatory assessment, ecological momentary assessment, experience sampling method, and real-time data capture. Even though the terms differ, they have in common the use of computer-assisted methodology to assess self-reported symptoms, behaviors, or physiological processes, while the participant undergoes normal daily activities. In this review we discuss the main features and advantages of ambulatory assessment regarding clinical psychology and psychiatry: (a) the use of realtime assessment to circumvent biased recollection, (b) assessment in real life to enhance generalizability, (c) repeated assessment to investigate within person processes, (d) multimodal assessment, including psychological, physiological and behavioral data, (e) the opportunity to assess and investigate context-specific relationships, and (f) the possibility of giving feedback in real time. Using prototypic examples from the literature of clinical psychology and psychiatry, we demonstrate that ambulatory assessment can answer specific research questions better than laboratory or questionnaire studies.

Monitoring of stress related physiological processes in ambulance personnel

2007 ◽  
Author(s):  
N. Kalezic ◽  
U. Aasa ◽  
M. Barnekow-Bergkvist ◽  
E. Lyskov
Keyword(s):  
Ambulance Personnel ◽  
Physiological Processes

Platelet Microtubules in Clot Structure Formation and Contractile Force Generation: Investigation of a Controversy

1986 ◽  
Vol 56 (01) ◽  
pp. 023-027 ◽  
Author(s):  
C J Jen ◽  
L V McIntire
Keyword(s):  
Network Formation ◽  
Contractile Force ◽  
Second Phase ◽  
Clot Retraction ◽  
Forming Process ◽  
Microtubule Organization ◽  
Physiological Processes ◽  
Fibrin Network ◽  
Two Parameters

SummaryWhether platelet microtubules are involved in clot retraction/ contraction has been controversial. To address this question we have simultaneously measured two clotting parameters, clot structural rigidity and isometric contractile force, using a rheological technique. For recalcified PRP clots these two parameters began rising together at about 15 min after CaCl2 addition. In the concentration range affecting microtubule organization in platelets, colchicine, vinca alkaloids and taxol demonstrated insignificant effects on both clotting parameters of a recalcified PRP clot. For PRP clots induced by adding small amounts of exogenous thrombin, the kinetic curves of clot rigidity were biphasic and without a lag time. The first phase corresponded to a platelet-independent network forming process, while the second phase corresponded to a platelet-dependent process. These PRP clots began generating contractile force at the onset of the second phase. For both rigidity and force parameters, only the second phase of clotting kinetics was retarded by microtubule affecting reagents. When PRP samples were clotted by adding a mixture of CaCl2 and thrombin, the second phase clotting was accelerated and became superimposed on the first phase. The inhibitory effects of micro tubule affecting reagents became less pronounced. Thrombin clotting of a two-component system (washed platelets/ purified fibrinogen) was also biphasic, with the second phase being microtubule-dependent. In conclusion, platelet microtubules are important in PRP clotted with low concentrations of thrombin, during which fibrin network formation precedes platelet-fibrin interactions. On the other hand they are unimportant if a PRP clot is induced by recalcification, during which the fibrin network is constructed in the presence of platelet-fibrin interactions. The latter is likely to be more analogous to physiological processes in vivo.

COVID-19 pathophysiology: interactions of gut microbiome, melatonin, vitamin D, stress, kynurenine and the alpha 7 nicotinic receptor: Treatment implications

2020 ◽  
Vol 3 (3) ◽  
pp. 322-345 ◽  
Author(s):  
George Anderson ◽  
Russel J Reiter
Keyword(s):  
Vitamin D ◽  
Coagulation Factors ◽  
Receptor Activation ◽  
Cytokine Induction ◽  
Aryl Hydrocarbon ◽  
Physiological Processes ◽  
Pulmonary Epithelial Cells ◽  
Vitamin D Levels ◽  
Complex Picture ◽  
Alpha 7

As data emerges on the pathophysiological underpinnings of severe acute respiratory syndrome coronavirus (SARS-CoV)-2, it is clear that there are considerable variations in its susceptibility and severity/fatality, which give indications as to its pathophysiology and treatment. SARS-CoV-2 modulatory factors include age, vitamin D levels, cigarette smoking, gender and ethnicity as well as premorbid medical conditions, including diabetes, cancer, obesity, cardiovascular disease, and immune-compromised conditions. A complex picture is emerging, with an array of systemic physiological processes interacting including circadian, immune, intestinal, CNS and coagulation factors. This article reviews data on SARS-CoV-2 pathoetiology and pathophysiology. It is proposed that a decrease in pineal and systemic melatonin is an important driver of SARS-CoV-2 susceptibility and severity, with the loss of pineal melatonin's induction of the alpha 7 nicotinic acetylcholine receptor (α7nAChR) in pulmonary epithelial cells and immune cells being a powerful regulator of susceptibility and severity, respectively. Stress, including discrimination stress, and decreased vitamin D also regulate SARS-CoV-2, including via gut dysbiosis and permeability, with a resultant decrease in the short-chain fatty acid, butyrate, and increase in circulating lipopolysaccharide. Stress and cytokine induction of the kynurenine pathways, leads to aryl hydrocarbon receptor activation, which primes platelets for heightened activity, coagulation and thrombin production, thereby driving elevations in thrombin that underpin many SARS-CoV-2 fatalities. On the basis of these pathophysiological changes, prophylactic and symptomatic treatments are proposed, including the use of melatonin and α7nAChR agonism. 

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