ATP-sensitive potassium channel subcellular trafficking during ischemia, reperfusion, and preconditioning

Ischemic preconditioning is an endogenous cardioprotective mechanism in which short periods of ischemia and reperfusion provide protection when given before a subsequent ischemic event. Early mechanistic studies showed ATP-sensitive potassium (KATP) channels to play an important role in ischemic preconditioning. KATP channels link intracellular energy metabolism to membrane excitability and contractility. It is thought that KATP channels provide a cardioprotective role during ischemia by inducing action potential shortening, reducing an excessive Ca^2+ influx, and by preventing arrhythmias. However, the mechanisms by which KATP channels protect during ischemic preconditioning are not known. In this study, we investigated a novel potential mechanism in which alterations in subcellular KATP channel trafficking during ischemia and ischemic preconditioning may result in altered levels of surface channel density, and therefore, a greater degree of cardioprotection. In the optimization of our experiments, we compared various antibodies for their specificity and sensitivity for channel subunit detection in immunoblotting. In addition, we examined the effects of varying salt concentrations during tissue homogenization in order to determine the optimal conditions for protein isolation. Furthermore, we examined the effect of heating the samples prior to SDS-PAGE for improved detection of channel proteins by immunoblotting. The subcellular trafficking of some membrane proteins is altered by ischemia. For example, the glucose transporter, Glut4, translocates from endosomal compartments to the sarcolemma (Sun, Nguyen, DeGrado, Schwaiger, & Brosius, 1994). Conflicting data exists regarding the effects of ischemia on KATP channel subcellular trafficking and the regulation of KATP channel surface density (Edwards et al., 2009 and Bao, Hadjiolova, Coetzee, & Rindler, 2011). We therefore, sought to test our hypothesis that KATP channels are internalized from the surface of cardiomyocytes to endosomal compartments during ischemia, and this internalization can be reduced and/or reversed by ischemic preconditioning. We subjected isolated Langendorff-perfused mouse hearts to ischemia, reperfusion, or ischemic preconditioning events and measured the density of KATP channels in the sarcolemmal and endosomal compartments. We also determined the degree of injury by staining heart slices with triphenyltetrazolium chloride and compared infarct sizes between hearts subjected to ischemia and ischemic preconditioning. Our data demonstrated that KATP channels are, in fact, internalized during ischemia and that reperfusion led to a slow recovery of surface KATP channel density. Interestingly, ischemic preconditioning reduced the size of infarcts induced by ischemia and also prevented the ischemia-induced decrease of KATP channel surface density, thereby, contributing to cardioprotection

Tolerance spaces and behavior

Tolerance spaces used in human behavior model

Interdependence of depressive symptoms, school involvement, and academic performance between adolescent friends: A dyadic analysis

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/113150/1/bjep12075.pd

3647 Sayılı ve 2008 (3647/2008) Tarihli Yunanistan Vakıflar Yasası ve Uygulamaları

[No Abstract Available

Reproductive insularity in a migratory sparrow: A field study of Lincoln\u27s sparrow populations in Southern California

Melospiza lincolnii -- San Bernardino and San Jacinto mountain ranges -- migrational return -- Dispersal - Morphometric analysis

The influence of direct experience of the physical environment on concept learning in physical geography

This investigation examines the relationship between children's direct experience of the physical environment and their conceptual understanding of it. In order to determine the extent of the influence of the physical environment on understanding, two groups of children living in different geographical environments were selected and their perceptions and understanding of the selected physical features related to their immediate surroundings were compared. The children's ideas about the features selected were examined using a number of research techniques. The results tended to support the central assertion of the study that the physical environment has an influence on children's conceptual understanding. The data also showed that the children held a number of alternative conceptions about their near and far environment prior to the experience of formal instruction. The relevance of these conclusions for geographical education is presented. Suggestions are made to improve the quality of teaching and learning in physical geography. Fieldwork, hardware models, simulation activities and Information and Communication Technology (ICT) are suggested for use as teaching approaches. The significance of the conclusions in the context of Turkish geographical education are also considered

The Relations Among Executive Dysfunction, Delay Aversion and Phonemic Awareness in Proschoolers

The Dual Pathways theory of AD/HD explains that there may be two independent neurologically based pathways in which AD/HD may develop: executive dysfunction (EDF) and delay aversion (DAv). A separate line of research has linked AD/HD to early reading problems. The purpose of this study was to further explore the two pathways of AD/HD in relation to the development of early literacy skills. More specifically, the relationship between EDF and DAv in preschoolers and phonemic awareness ability was examined. Using a hierarchical regression, it was indicated that there was a statistically significant relationship between EDF scores and levels of inattention as rated by teachers. Teacher-rated hyperactivity/impulsivity was also significantly correlated with our early literacy outcome measure, indicating a possible connection between these two variables. No significant relationships emerged between EDF or DAv and the early literacy measure. Future research should explore the role of teacher-reported inattention as a potential mediator of EDF and preliteracy development. Lastly, a third pathway has recently been proposed; the pathways model should be explored further using multiple measures for each to determine potential relationships with common functional impairments such as literacy development.  M.A

EXAMINATION OF ATTITUDES OF SECONDARY SCHOOL STUDENTS TOWARDS TURKISH COURSE ACTIVITIES

In this study, it was aimed to determine the attitudes of secondary school students towards Turkish course activities according to various variables. In order to determine the sample of the study, deviant case sampling, which is one of the purposeful sampling methods, was used. With the mentioned sampling method, the sample of the study consists of three middle schools which are located in the city center of Erzurum and 2018 TEOG success ranking of which are the high grade, middle and low grade. 400 students participated in total. Of these, 96 were 5th graders, 88 were 6th graders, 105 were 7th graders and 111 were 8th graders. The screening model was used in the study. In order to determine the attitudes of the students, who compose the sample of the study, towards Turkish lesson activities, “Attitude Scale towards Activities of Turkish Course” developed by Çerçi and Derman (2016) was used. Obtained data were analyzed by SPSS 22.0 package program. As a result of the study, it was determined that secondary school students' attitudes towards Turkish course did not differ according to school level, it significantly differentiated according to the class level, the grade point average of the 5th grade students was higher than the average of the upper grade students, there was a significant difference in favor of the students who had higher grade point average compared to the Turkish course average, The grade point average of the students with high Turkish course average was higher than those with a lower grade point average and according to the gender, the difference between girl and boy students was significant in favor of girls. The results of the study were discussed with the studies in the field literature which examine the attitudes of secondary schools students towards Turkish course, reading, speaking and writing skills and suggestions were made.  Article visualizations

Deep lithospheric dynamics beneath the Sierra Nevada during the Mesozoic and Cenozoic as inferred from xenolith petrology

Peridotite xenoliths erupted in late Miocene basalts (~8 Ma) in the central Sierra Nevada sample a lithosphere that is vertically stratified in terms of age and thermal history. The deeper portions (~45-100 km) have asthenospheric osmium isotopic compositons and possess textural and chemical evidence for cooling from >1100° to 700-820°C. The shallower portions (<60 km) have unradiogenic Os isotopic compositions, which yield Proterozoic model ages, and contain orthopyroxenes that record temperatures as low as 670°C in their cores and heating up to 900°C on their rims. These observations suggest that the deeper xenoliths represent fragments of hot asthenosphere that upwelled to intrude and/or underplate the overlying Proterozoic lithosphere represented by the shallower xenoliths. The contrasting thermal histories between the shallow and deep xenoliths suggest that hot asthenosphere and cold lithosphere were suddenly juxtaposed, a feature consistent with the aftermath of rapid lithospheric removal or sudden intrusion of asthenospheric mantle into the lithosphere rather than passive extension. On the basis of regional tectonics and various time constraints, it is possible that this lithospheric removal event was associated with the generation of the Sierra Nevada granitic batholith during Mesozoic subduction of the Farallon plate beneath North America. Pleistocene basalt-hosted xenoliths record a different chapter in the geodynamic history of the Sierras. These xenoliths are relatively fertile, come from depths shallower than 45-60 km, are characterized by asthenospheric Os isotopic compositions, record hot equilibration temperatures (1000°-1100°C), and show no evidence for cooling. The strong contrast in composition and thermal history between the Pleistocene and late Miocene suites indicate that the post-Mesozoic lithospheric mantle, as represented by the latter, was entirely replaced by the former. The hot Pleistocene peridotites may thus represent new lithospheric additions associated with a post-Miocene lithospheric removal event or extension. High elevations, low sub-Moho seismic velocities, and the presence of fast velocity anomalies at 200 km depth may be manifestations of this event. If lithospheric removal occurred in the Mesozoic and Cenozoic, the observations presented here place constraints on the styles of lithospheric removal. In the Mesozoic, the lithospheric mantle was only partially removed, whereas in the Pliocene, the entire lithospheric mantle and probably the mafic lower crust were removed

Micro-circuit reticle fabrication: an investigation of a silver halide emulsion as a portable conformable mask

An investigation of the possibility of spin-coating a silver halide emusion similar to that used on Kodak HRP plates onto a positive resist coating reticle blank was made. By changing the cating weight and temperature of the emulsion it was found that the emulsion could be coated onto the reticle without harm to the positive resist material. A five micron width line was imaged successfully and measured in the final chrome sub-layer of the reticle