Effect of astrocyte on synchronization of thermosensitive neuron-astrocyte minimum system

2022 ◽  
Author(s):  
Yi-Xuan Shan ◽  
Hui-Lan Yang ◽  
Hong-Bin Wang ◽  
Shuai Zhang ◽  
Ying Li ◽  
...  
Keyword(s):  
Pyramidal Cell ◽  
Nonlinear Behavior ◽  
Regulatory Function ◽  
Inositol Triphosphate ◽  
Temperature Sensitive ◽  
Temperature Range ◽  
A Value ◽  
Change Characteristics ◽  
The Central Nervous System ◽  
Minimum System

Abstract Astrocytes have a regulatory function on the central nervous system (CNS), especially in the temperature sensitive hippocampal region. In order to explore the thermosensitive dynamic mechanism of astrocytes in CNS, we establish a neuron-astrocyte minimum system to analyze the synchronization change characteristics based on Hodgkin-Huxley model, in which a pyramidal cell and an interneuron are connected by an astrocyte. Besides, the temperature range set 0°C-40°C to juggle theoretical calculation and reality of brain environment. It is represented that the synchronization of thermosensitive neurons exhibits nonlinear behavior with change of astrocyte parameters. At temperature range of 0°C-18°C, the effects of astrocyte can provide tremendous influence to neurons in synchronization. We found existence of a value for inositol triphosphate (IP3) production rate and feedback intensities of astrocyte to neurons, which can ensure the weak synchronization of two neurons. In addition, it is revealed that the regulation of astrocyte to pyramidal cell is more sensitive than that to interneuron. Finally, it is shown that the synchronization and phase transition of neurons depend on the change of Ca2+ concentration at the temperature of weak synchronization. The results in this paper would provide some enlightenment in mechanism of cognitive dysfunction and neurological disorders with astrocytes.

Effects of Nb doping on thermoelectric properties of Zn4Sb3 at high temperatures

2009 ◽  
Vol 24 (2) ◽  
pp. 430-435 ◽  
Author(s):  
D. Li ◽  
H.H. Hng ◽  
J. Ma ◽  
X.Y. Qin
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
High Temperatures ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Thermoelectric Performance ◽  
Temperature Range ◽  
A Value ◽  
Nb Doping ◽  
Thermal Conductivities

The thermoelectric properties of Nb-doped Zn4Sb3 compounds, (Zn1–xNbx)4Sb3 (x = 0, 0.005, and 0.01), were investigated at temperatures ranging from 300 to 685 K. The results showed that by substituting Zn with Nb, the thermal conductivities of all the Nb-doped compounds were lower than that of the pristine β-Zn4Sb3. Among the compounds studied, the lightly substituted (Zn0.995Nb0.005)4Sb3 compound exhibited the best thermoelectric performance due to the improvement in both its electrical resistivity and thermal conductivity. Its figure of merit, ZT, was greater than the undoped Zn4Sb3 compound for the temperature range investigated. In particular, the ZT of (Zn0.995Nb0.005)4Sb3 reached a value of 1.1 at 680 K, which was 69% greater than that of the undoped Zn4Sb3 obtained in this study.

An anomaly in the specific heat below 3 °K of copper containing hydrogen

1969 ◽  
Vol 47 (14) ◽  
pp. 1485-1491 ◽  
Author(s):  
Neil Waterhouse
Keyword(s):  
Specific Heat ◽  
Molecular Hydrogen ◽  
Pure Copper ◽  
Solid Hydrogen ◽  
Rotational State ◽  
Experimental Results ◽  
Ortho Hydrogen ◽  
Temperature Range ◽  
A Value ◽  
Heat Curve

The specific heat of copper heated in hydrogen at 1040 °C has been measured over the temperature range 0.4 to 3.0 °K and found to be anomalous. The anomaly occurs in the same temperature range as the solid hydrogen λ anomaly which, in conjunction with evidence of ortho to para conversion of hydrogen in the sample, suggests the presence of molecular hydrogen in the copper. The anomaly reported by Martin for "as-received" American Smelting and Refining Company (ASARCO) 99.999+ % pure copper has been briefly compared with the present results. The form of the anomaly produced by the copper-hydrogen specimen has been compared with Schottky curves using the simplest possible model, that for two level splitting of the degenerate J = 1 rotational state of the ortho-hydrogen molecule.Maintenance of the copper-hydrogen sample at ~20 °K for approximately 1 week removed the "hump" in the specific heat curve. An equation of the form Cp = γT + (464.34/(θ0c)3)T3 was found to fit these experimental results and produced a value for γ which had increased over that for vacuumannealed pure copper by ~2%.

scholarly journals Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) in Physiological and Pathological Processes within the Gastrointestinal Tract: A Review

2021 ◽  
Vol 22 (16) ◽  
pp. 8682
Author(s):  
Aleksandra Karpiesiuk ◽  
Katarzyna Palus
Keyword(s):  
Adenylate Cyclase ◽  
Smooth Muscle Contraction ◽  
Regulatory Function ◽  
Gi Tract ◽  
Cytoprotective Effect ◽  
Neoplastic Processes ◽  
Pituitary Adenylate Cyclase ◽  
Pleiotropic Action ◽  
Tract Function ◽  
The Central Nervous System

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide widely distributed in the central nervous system (CNS) and many peripheral organs, such as the digestive tract, endocrine, reproductive and respiratory systems, where it plays different regulatory functions and exerts a cytoprotective effect. The multifarious physiological effects of PACAP are mediated through binding to different G protein-coupled receptors, including PAC1 (PAC1-R), VPAC1 (VPAC1-R) and VPAC2 (VPAC2-R) receptors. In the gastrointestinal (GI) tract, PACAP plays an important regulatory function. PACAP stimulates the secretion of digestive juices and hormone release, regulates smooth muscle contraction, local blood flow, cell migration and proliferation. Additionally, there are many reports confirming the involvement of PACAP in pathological processes within the GI tract, including inflammatory states, neuronal injury, diabetes, intoxication and neoplastic processes. The purpose of this review is to summarize the distribution and pleiotropic action of PACAP in the control of GI tract function and its cytoprotective effect in the course of GI tract disorders.

scholarly journals The system CaO-MgO-FeO-SiO2 and its bearing on the origin of ultrabasic and basic rocks

1960 ◽  
Vol 32 (249) ◽  
pp. 459-470 ◽  
Author(s):  
Peter J. Wyllie
Keyword(s):  
Experimental Data ◽  
Temperature Interval ◽  
Wide Temperature Range ◽  
Multicomponent System ◽  
Small Temperature ◽  
Experimental Procedure ◽  
Temperature Range ◽  
A Value ◽  
Basaltic Magmas ◽  
Basic Rocks

SummaryExperimental data in the system CaO-MgO-FeO-SiO2 suggest that there may be a plateau on the liquidus and solidus of the multicomponent system basalt-peridotite. If this is so, fusion of peridotite would produce only basaltie magmas over a wide temperature range; when the temperature reached a value such that the liquid crossed the threshold of the plateau, there would be a rapid increase in the amount of fusion for small temperature increases, with the formation of picritic magmas; basaltic magmas containing suspended forsteritic olivine crystals could dissolve them if the temperature rose slightly above that of the plateau threshold; a high proportion of a picritic magma would crystallize in a small temperature interval, with the precipitation of forsteritic olivine that was only slightly zoned. These possibilities are compared with current theories, and it is concluded that several petrological axioms may require critical re-examination. An experimental procedure is outlined to determine the shape of the liquidus and solidus in the basalt-peridotite system.

scholarly journals Phonon hydrodynamics and ultrahigh–room-temperature thermal conductivity in thin graphite

Science ◽  
2020 ◽  
Vol 367 (6475) ◽  
pp. 309-312 ◽  
Author(s):  
Yo Machida ◽  
Nayuta Matsumoto ◽  
Takayuki Isono ◽  
Kamran Behnia
Keyword(s):  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Wide Temperature Range ◽  
Room Temperature ◽  
Phonon Dispersion ◽  
High Conductivity ◽  
Temperature Range ◽  
A Value ◽  
Out Of Plane ◽  
Intimate Link

Allotropes of carbon, such as diamond and graphene, are among the best conductors of heat. We monitored the evolution of thermal conductivity in thin graphite as a function of temperature and thickness and found an intimate link between high conductivity, thickness, and phonon hydrodynamics. The room-temperature in-plane thermal conductivity of 8.5-micrometer-thick graphite was 4300 watts per meter-kelvin—a value well above that for diamond and slightly larger than in isotopically purified graphene. Warming enhances thermal diffusivity across a wide temperature range, supporting partially hydrodynamic phonon flow. The enhancement of thermal conductivity that we observed with decreasing thickness points to a correlation between the out-of-plane momentum of phonons and the fraction of momentum-relaxing collisions. We argue that this is due to the extreme phonon dispersion anisotropy in graphite.

Kinetics of the hydrolysis of cellobiose and p-nitrophenyl-β-D-glucoside by cellobiase of Trichoderma viride

1977 ◽  
Vol 55 (1) ◽  
pp. 19-26 ◽  
Author(s):  
R. James Maguire
Keyword(s):  
Steady State ◽  
Trichoderma Viride ◽  
Solution Temperature ◽  
Temperature Range ◽  
A Value ◽  
Steady State Kinetics ◽  
Decreasing Ph ◽  
Ph Curve ◽  
Kinetics Of ◽  
Hydrolysis Of

Cellobiase has been isolated from the crude cellulase mixture of enzymes of Trichoderma viride using column chromatographic and ion-exchange methods. The steady-state kinetics of the hydrolysis of cellobiose have been investigated as a function of cellobiose and glucose concentrations, pH of the solution, temperature, and dielectric constant, using isopropanol–buffer mixtures. The results show that (i) there is a marked activation of the reaction by initial glucose concentrations of 4 × 10−3 M to 9 × 10−2 M and strong inhibition of the reaction at higher initial concentrations, (ii) the log rate – pH curve has a maximum at pH 5.2 and enzyme pK values of 3.5 and 6.8, (iii) the energy of activation at pH 5.1 is 10.2 kcal mol−1 over the temperature range 5–56 °C, and (iv) the rate decreases from 0 to 20% (v/v) isopropanol.The hydrolysis by cellobiase (EC 3.2.1.21) of p-nitrophenyl-β-D-glucoside was examined by pre-steady-state methods in which [Formula: see text], and by steady-state methods as a function of pH and temperature. The results show (i) a value for k2 of 21 s−1 at pH 7.0 (where k2 is the rate constant for the second step in the assumed two-intermediate mechanism [Formula: see text]) (ii) a log rate–pH curve, significantly different from that for hydrolysis of cellobiose, in which the rate increases with decreasing pH below pH 4.5, is constant in the region pH 4.5–6, and decreases above pH 6 (exhibiting an enzyme pK value of 7.3), and (iii) an activation energy of 12.5 kcal mol−1 at pH 5.7 over the temperature range 10–60 °C.

Hypoxial death inferred from thermally induced injuries at upper lethal temperatures, in the banded killifish, Fundulus diaphanus (LeSueur)

1977 ◽  
Vol 55 (10) ◽  
pp. 1705-1719 ◽  
Author(s):  
P. J. Rombough ◽  
E. T. Garside
Keyword(s):  
Cell System ◽  
Short Exposure ◽  
Temperature Sensitive ◽  
Thermally Induced ◽  
Lethal Temperatures ◽  
Ultimate Cause ◽  
The Central Nervous System ◽  
Trunk Musculature ◽  
Banded Killifish ◽  
Fundulus Diaphanus

Banded killifish, Fundulus diaphanus (LeSueur), acclimated to 25 °C were subjected to upper lethal temperatures using a 10 000 min bioassay procedure. The incipient upper lethal temperature (LT50) was about 34.5 °C. Histologic examination of heat-treated fish revealed no obvious injury to the heart, spleen, trunk musculature, eye, naris, integument, or digestive tract.Thermal stress induced progressive injury to the gills characterized by subepithelial edema, congestion of lamellar capillaries, and delamination of the respiratory epithelium from the pillar cell system. Areas of necrosis were observed in the lobus inferior of the hypothalamus and in the medulla oblongata. The pseudobranch epithelium was necrotic. Fatty change occurred in the liver. Acinar cells of the pancreas appeared autolytic and adjacent blood vessels damaged. Degenerative tubular changes and contracted glomerular tufts were noted in the kidney. The ovary was extremely temperature sensitive and displayed severe injury to oocytes and follicular cells after relatively short exposure to temperatures near the LT50.It is proposed that primary thermally induced injury is to the gills. This results in abnormal gas exchange and osmoregulation and leads to pathologic changes in other tissues. Hypoxia of the central nervous system appears to be the ultimate cause of death.

scholarly journals CD56bright Natural Killer Cells: A Possible Biomarker of Different Treatments in Multiple Sclerosis

2020 ◽  
Vol 9 (5) ◽  
pp. 1450 ◽  
Author(s):  
Alice Laroni ◽  
Antonio Uccelli
Keyword(s):  
Multiple Sclerosis ◽  
Nk Cells ◽  
Natural Killer ◽  
Dimethyl Fumarate ◽  
Regulatory Function ◽  
Clinical Activity ◽  
Hematopoietic Stem ◽  
Immune Mediated ◽  
The Central Nervous System ◽  
Magnetic Resonance Imaging Mri

Multiple sclerosis (MS) is an immune-mediated disease of the central nervous system, which leads, in many cases, to irreversible disability. More than 15 disease-modifying treatments (DMTs) are available for the treatment of MS. Clinical activity or activity at magnetic resonance imaging (MRI) are now used to assess the efficacy of DMTs, but are negative prognostic factors per se. Therefore, a biomarker permitting us to identify patients who respond to treatment before they develop clinical/radiological signs of MS activity would be of high importance. The number of circulating CD56bright natural killer (NK) cells may be such a biomarker. CD56bright NK cells are a regulatory immune population belonging to the innate immune system. The number of CD56bright NK cells increases upon treatment with interferon-beta, alemtuzumab, dimethyl fumarate, after autologous hematopoietic stem cell transplantation, and is higher in those who respond to fingolimod. In some cases, an increased number of CD56bright NK cells is associated with an increase in their regulatory function. In the current review, we will evaluate the known effect on CD56bright NK cells of DMTs for MS, and will discuss their possible role as a biomarker for treatment response in MS.

Sign in / Sign up

Export Citation Format

Share Document