scholarly journals Characterization of legacy organic carbon in a culturally eutrophic lake : the role of the historic carbon deposition in the time course and extent of lake recovery

2010 ◽  
Author(s):  
Phillip A. DePetro
Keyword(s):  
Organic Carbon ◽  
Time Course ◽  
Carbon Deposition ◽  
Eutrophic Lake ◽  
Lake Recovery

Molecular characterization of chicken Janus kinase2 (JAK2) and its expression analysis in different tissues and cell lines

2019 ◽  
Author(s):  
Abdalla A. Sayed
Keyword(s):  
Cell Lines ◽  
Expression Analysis ◽  
Time Course ◽  
Signal Transducer ◽  
Stat Proteins ◽  
Tyrosine Residues ◽  
Wide Range ◽  
Human And Mouse

Janus kinase2 (JAK2) is one of an important family that function primarily in signal transduction through contact with signal transducer and activator of transcription (STAT) proteins which reflects the high important role of JAK2 and its family. Chicken JAK2 protein is found to be formed of 1129 amino acids. The phosphorylation tyrosine residues were conserved between chicken, human and mouse. Expression analysis of chicken JAK2 showed a wide range of expression in all used tissues and cell lines. The expression was high in T-cell fraction when compared with that of B-cell one. The expression of chicken JAK2 showed a time course dependent of lipopolysaccharide (LPS) stimulation in spleen and bursa tissues and in IN24 cell line. The stimulation by LPS showed a high expression of chicken JAK2 in spleen and bursa by in-stiu hybridization studies.

Abstract 650: Characterization of Microparticles Formed by ABCA1

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Anouar Hafiane ◽  
John K Bielicki ◽  
Jan O Johansson ◽  
Jacques Genest
Keyword(s):  
Time Course ◽  
Physiological Role ◽  
Cell Types ◽  
Cholesterol Content ◽  
Hydrodynamic Diameter ◽  
Bhk Cells ◽  
Apo E ◽  
Time Course Study

Microparticles (MPS) are lipoprotein-sized structures created by the ABCA1 transporter. Their biological roles in health and in disease remain unknown. Here, we study MPS released from baby hamster kidney (BHK) cells stably expressing ABCA1 and human THP-1 cells also expressing ABCA1. Media cell culture was first collected from BHK-ABCA1 expressing cells after (45min, 2, 4, 8, and 24h) incubation. After centrifugation (4000xg for 15min and 10000xg for 30min) to remove cell debris, the supernatant was passed through a 10kDa cutoff filter and subsequently subjected to analytical FPLC. FPLC analysis shows creation of a single peak in the presence of ABCA1 but not in mock-transfected BHK cells. In a time-course study, the estimated hydrodynamic diameter remained stable (≥20nm). After 8h incubation of BHK cell with apoA-I or an apo-E mimetic peptide, CS-6253 (1μM), ABCA1 mediated formation of MPS of similar size with a significant increase in 3[H]-FC content than those generated by ABCA1 alone, (373±23 % cpm, P<0.05) and (277±60 % cpm, P<0.05) respectively. This was associated with highly lipidated nHDL-CS-6253 compararely to nHDL-apoA-I (4535±72 % cpm, P<0.001 versus 1059±14 % cpm) respectively. This data suggests that MPS formations are an integral component of cellular cholesterol efflux. Also, MPS do not contain CS-6253 when ABCA1 cells were incubated with the peptide as confirmed by western blotting similar to MPS generated from ABCA1 cells generated by apoA-I incubation. Cholesterol is effluxed more to nHDL-CS-6253 (14±7.68, % cpm, P<0.01 than to MPS 1±0.10, % cpm, 24h; P<0.01) similar to apoA-I. Depletion of membrane cholesterol by methyl-β-cyclodextrin treatment impaired HDL genesis and decrease MPS release. Detection of flotellin-2 protein enriched in MPS in total cell lysate indicated that these MPS may be related to exosomes. MPS generation was also characterized in THP-1 cells for further molecular characterization. We conclude that MPS are formed by ABCA1 in diverse cell types and the cholesterol content is dependent on activation by apo A-I or mimetic peptides. The physiological role of MPS remains to be understood. These particles may be transporters of lipids and nucleic acids.

Diluting segment in kidney of dogfish shark. I. Localization and characterization of chloride absorption

1990 ◽  
Vol 258 (2) ◽  
pp. R398-R408 ◽  
Author(s):  
P. A. Friedman ◽  
S. C. Hebert
Keyword(s):  
Time Course ◽  
Osmotic Gradient ◽  
Diluting Segment ◽  
A Value ◽  
Chloride Absorption ◽  
Transepithelial Voltage ◽  
Dogfish Shark

Single tubules, dissected from the peritubular sheath of the dorsal bundle zone of kidney of the dogfish shark, Squalus acanthias, were perfused in vitro at 17-18 degrees C. This segment is the largest of the five in the peritubular sheath and had average inner and outer diameters of 46.9 +/- 1.2 and 74.4 +/- 2.1 microns, respectively (n = 32). These values suggest that this is the intermediate IV segment. When perfused with symmetrical buffered elasmobranch saline, intermediate IV segments exhibited high rates of Cl- absorption (JCl, pmol.s-1.cm-2): 1,696 at an average perfusion rate (Vo) of 8.2 nl/min. Cl- absorption was highly flow dependent [1/JCl = 57.95(1/Vo) + 1.75; r = 0.71, P less than 0.01]. Maximal rates of Cl-absorption, calculated from reciprocal transformation of the flow dependence of JCl, yielded a value of 5,714 pmol.s-1.cm-2. In the presence of a 200-mosmol/kg transepithelial osmotic gradient, fluid absorption was negligible. The spontaneous transepithelial voltage (Vte, mucosal with respect to serosal compartment) averaged 8.0 +/- 1.0 mV (n = 26). Such active transport of Cl- in the absence of fluid movement and in the presence of a lumen-positive transepithelial voltage is characteristic of amphibian and mammalian diluting segments. Na(+)-to-Cl- permeability ratios (PNa/PCl) averaged 2.5 +/- 0.5, indicating that, as in mammalian thick ascending limbs, this segment is Na+ (cation) permselective. Vte was dependent on the presence of Na+ and Cl- in the external solutions and was reversibly abolished by isosmotic replacement with N-methyl-D-glucamine or with isethionate, respectively. Ouabain inhibited Vte but was not reversible within the time course of these experiments. Furosemide (10(-4) M), but not equimolar concentrations of amiloride or hydrochlorothiazide, added to the luminal perfusate inhibited both Vte and JCl. These results suggest that apical membrane Na+ entry in intermediate IV segments is mediated by Na(+)-K(+)-Cl- cotransport and is consistent with the existence of a functional role of urinary dilution in the reabsorption of urea in the elasmobranch kidney.

Digital x-ray mapping of nanometer-size supported bimetallic catalysts

1988 ◽  
Vol 46 ◽  
pp. 530-531
Author(s):  
L. T. Germinario
Keyword(s):  
Background Radiation ◽  
Metal Cluster ◽  
Single Element ◽  
Beam Diameter ◽  
X Rays ◽  
X Ray ◽  
Major Interest ◽  
Induced Changes

Understanding the role of metal cluster composition in determining catalytic selectivity and activity is of major interest in heterogeneous catalysis. The electron microscope is well established as a powerful tool for ultrastructural and compositional characterization of support and catalyst. Because the spatial resolution of x-ray microanalysis is defined by the smallest beam diameter into which the required number of electrons can be focused, the dedicated STEM with FEG is the instrument of choice. The main sources of errors in energy dispersive x-ray analysis (EDS) are: (1) beam-induced changes in specimen composition, (2) specimen drift, (3) instrumental factors which produce background radiation, and (4) basic statistical limitations which result in the detection of a finite number of x-ray photons. Digital beam techniques have been described for supported single-element metal clusters with spatial resolutions of about 10 nm. However, the detection of spurious characteristic x-rays away from catalyst particles produced images requiring several image processing steps.

Microstructural and fractographic characterization of B4C-Al cermets tested under dynamic and static loading

1989 ◽  
Vol 47 ◽  
pp. 562-563
Author(s):  
Gyeung Ho Kim ◽  
Mehmet Sarikaya ◽  
D. L. Milius ◽  
I. A. Aksay
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Static Loading ◽  
Carbon Deposition ◽  
Full Density ◽  
Unique Combination ◽  
Strong Component ◽  
Reaction Products

Cermets are designed to optimize the mechanical properties of ceramics (hard and strong component) and metals (ductile and tough component) into one system. However, the processing of such systems is a problem in obtaining fully dense composite without deleterious reaction products. In the lightweight (2.65 g/cc) B4C-Al cermet, many of the processing problems have been circumvented. It is now possible to process fully dense B4C-Al cermet with tailored microstructures and achieve unique combination of mechanical properties (fracture strength of over 600 MPa and fracture toughness of 12 MPa-m1/2). In this paper, microstructure and fractography of B4C-Al cermets, tested under dynamic and static loading conditions, are described.The cermet is prepared by infiltration of Al at 1150°C into partially sintered B4C compact under vacuum to full density. Fracture surface replicas were prepared by using cellulose acetate and thin-film carbon deposition. Samples were observed with a Philips 3000 at 100 kV.

Collagen-Induced Platelet Aggregation: -Evidence Against the Essential Role of Platelet Adenosine Diphosphate

1979 ◽  
Vol 42 (04) ◽  
pp. 1193-1206 ◽  
Author(s):  
Barbara Nunn
Keyword(s):  
Platelet Aggregation ◽  
Time Course ◽  
Essential Role ◽  
Atp Release ◽  
Adenosine Diphosphate ◽  
Human Platelets ◽  
High Doses ◽  
Induced Aggregation

SummaryThe hypothesis that platelet ADP is responsible for collagen-induced aggregation has been re-examined. It was found that the concentration of ADP obtaining in human PRP at the onset of aggregation was not sufficient to account for that aggregation. Furthermore, the time-course of collagen-induced release in human PRP was the same as that in sheep PRP where ADP does not cause release. These findings are not consistent with claims that ADP alone perpetuates a collagen-initiated release-aggregation-release sequence. The effects of high doses of collagen, which released 4-5 μM ADP, were not inhibited by 500 pM adenosine, a concentration that greatly reduced the effect of 300 μM ADP. Collagen caused aggregation in ADP-refractory PRP and in platelet suspensions unresponsive to 1 mM ADP. Thus human platelets can aggregate in response to collagen under circumstances in which they cannot respond to ADP. Apyrase inhibited aggregation and ATP release in platelet suspensions but not in human PRP. Evidence is presented that the means currently used to examine the role of ADP in aggregation require investigation.

Consideraciones en torno a la reducción solipsista

1970 ◽  
Vol 11 ◽  
Author(s):  
Natalia Carolina Petrillo

ResumenEn el presente trabajo se intentará mostrar que la fenomenología no conduce a una postura solipsista. Para ello, se caracterizará en qué consiste el solipsismo. Luego, se intentará refutar a lo que se ha de llamar “solipsismo metafísico” y “solipsismo gnoseológico”, con el objetivo principal de poner de manifiesto el fundamento de motivación para la salida de la ficción solipsista.Palabras claves:Phenomenology – solipsim – empatía - HusserlAbstractWith the aim of showing that phenomenology does not lead in solipsism, I will first attempt a characterization of it. Then, I will attempt a refutation of the so-called “metaphysical” and “epistemological” solipsisms. Finally, the nature and role of Husserl´s solipsistic fiction is examined, and the grounds that motivate the overcoming of this standpoint are disclosed.key wordsFenomenología – solipsismo - empathy – Husserl

ART STUDIOS – A WAY TO DEVELOPE CHILDREN’S IMAGINATION

2020 ◽  
Vol 11 (1) ◽  
pp. 144-148
Author(s):  
Liuba Zlatkova ◽  
Keyword(s):  
Fairy Tale ◽  
Psychological Effects ◽  
Complete Product ◽  
The Arts ◽  
The Creation ◽  
Role Of Parents

The report describes the steps for creating a musical tale by children in the art studios of „Art Workshop“, Shumen. These studios are led by students volunteers related to the arts from pedagogical department of Shumen University, and are realized in time for optional activities in the school where the child studies. The stages of creating a complete product with the help of different arts are traced – from the birth of the idea; the creation of a fairy tale plot by the children; the characterization of the fairy-tale characters; dressing them in movement, song and speech; creating sets and costumes and creating a finished product to present on stage. The role of parents as a link and a necessary helper for children and leaders is also considered, as well as the positive psychological effects that this cooperation creates.

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