The effect of storage time and freeze-thaw cycles on the stability of serum samples

Introduction:

Optimal storage of serum specimens in central laboratories for a long period for multicenter reference interval studies, or epidemiologic studies remains to be determined. We aimed to examine the analytical stability of chemistry analytes following numerous freeze-thaw and long term storage.

Materials and methods:

Serum samples were obtained from 15 patients. Following baseline measurement, sera of each subject were aliquoted and stored at −20 °C for two experiments. A group of sera were kept frozen for up to 1, 2 and 3 months and then analyzed for stability. The other experiment consisted of one to ten times of freeze and thaw cycles. Total of 17 chemistry analytes were assayed at each time point. The results were compared with those obtained from the initial analysis of fresh samples. Median or mean changes from baseline (T₀) concentrations were evaluated both statistically and clinically according to the desirable bias.

Results:

Of the analytes studied, aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine kinase (CK), gamma-glutamyl transferase (GGT), direct bilirubin, glucose, creatinine, cholesterol, triglycerides, high density lipoprotein (HDL) were stable in all conditions. Blood urea nitrogen (BUN), uric acid, total protein, albumin, total bilirubin, calcium, lactate dehydrogenase (LD) were changed significantly (P < 0.005).

Conclusions:

As a result, common clinical chemistry analytes, with considering the variability of unstable analytes, showed adequote stability after 3 months of storage in sera at −20 °C, or up to ten times of freeze-thaw cycle. All the same, such analysis can only be performed for exceptional cases, and this should be taken into account while planning studies.     

The Assessment of Oxidative Stress on Patients with Chronic Renal Failure at Different Stages and on Dialysis Patients Receiving Different Hypertensive Treatment

The aim of this study is to evaluate the oxidative stress in predialysis, hemodialysis (HD) and peritoneal dialysis patients and to test the effects of antihypertensive drugs and volume control on oxidative stress parameters. The study was composed of five groups as follows: control group (n = 30), predialysis group (n = 30), peritoneal dialysis group (n = 30), hemodialysis group, (normotensive with strict volume control, n = 30), hemodialysis group (normotensive with medication, n = 30). Plasma malondialdehyde (MDA), erythrocyte superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx) and routine biochemical parameters were studied in all patients. Hemodialysis patients with strict volume control (HD_vc) had lower levels of MDA than other patient groups (p < 0.001), and CAT, SOD values had highest level other patient groups (p < 0.001). The treatment of hypertension with strict volume control in chronic renal failure patients causes less damage to the antioxidant capacity.     

Predictors of Academic Stress Among College Students

The purpose of this study was to examine factors predictive of college students' academic stress. Three hundred seven undergraduate students (179 men, 128 women) participated in the study. Results indicated that female college students had higher academic stress than did male college students. Bivariate correlations and multiple regression analyses revealed that life satisfaction, locus of control, and gender were significant predictors of academic stress. Directions for future research and implications for counselors are discussed.     

Education and symbolic violence in contemporary Turkey

This article examines the perceptions of education in Turkey, which refer to a nebulous package of formal education and a cultured stance. Guided by the literature on symbolic violence, we argue that underprivileged groups misrecognize arbitrary hierarchies by considering them just and inevitable. Elite tastes have been internalized by other groups in a particular historical context of education and culture. We investigate the historical roots of this seemingly ahistorical constellation of power relations around education and then consider the implications for the neoliberal period. Then, we contextualize the responses to symbolic violence. Subordinate groups complicate the effects of symbolic violence by exhibiting diverse responses that range from outright submission to implicitly questioning cultural and moral boundaries, creating class and ethnic others in the process. This occurs by constructing cultural and moral boundaries, especially targeting the ‘vulgar’ culture of celebrities and Kurds.     

Turkish School Counselors and Counselor Educators’ Perceptions about Multicultural Counseling

This paper examines the topic of multicultural counseling in Turkey, where school-based multicultural counseling services remain comparatively limited in scope and application. Participants consisted of twenty-three counselors working in secondary or high schools and fourteen counselor educators from several state universities. While the participants expressed mostly positive attitudes towards multicultural counseling, school counselors tended to regard it only as a client-focused, acculturation process. Not unexpectedly, counselor educators approached the process mainly in terms of how to effectively apply it toward various minority groups in Turkey.     

Examining students’ perceptions of plagiarism: A cross-cultural study at tertiary level

Plagiarism continues to dominate the academic world as one of its greatest challenges, and the existing literature suggests cross-cultural investigation of this critical issue may help all shareholders who detect, are confronted by and struggle with this issue to address it. Therefore, the present study, drawing upon a cross-cultural investigation using a questionnaire, aimed to investigate the differences between three groups of students, namely, Turkish (n = 106), Georgian (n = 83) and German (n = 72) regarding their tendency to conduct academic theft. It also investigated ways in which to plagiarise and reasons for and awareness of this issue. The results show that lack of time, busy schedules and weak academic writing skills are the most frequent reasons for plagiarism. However, in contrast to previous studies, the role of the Internet was found to be minimal in relation to increasing plagiarism. It is also worth noting that the German participants were found to have a higher level of sensitivity to this academic malpractice and were seen to be much more successful at identifying it. The article concludes with workable suggestions on how to discourage academic theft at universities.     

Why are some universities better? An evaluation in terms of organizational culture and academic performance*

ABSTRACT

The purpose of this study is to investigate the relationships between organizational culture and academic performance among higher education institutions. The sample was composed of 647 faculty members working in the colleges of education, health, engineering, law, economics, and administrative sciences in four central research universities in Turkey. The Organizational Culture Assessment Instrument (OCAI) was used to describe organizational culture, whereas University Ranking by Academic Performance (URAP) data were used to investigate academic performance. A multilevel analysis in which one unit of analysis (i.e., faculty member) was nested within another (i.e., college) was performed. The original contribution made to the literature by this research is its examination of the relationships between organizational culture and tangible performance indicators (e.g., the number of academic publications and citations). Results show that three different culture types were observed in the universities: Innovative team culture, competitive culture, and hierarchic culture. Although significant relationships were found between academic performance and both competitive culture and innovative team culture, the sole significant predictor of academic performance was competitive culture. One particularly interesting finding was that whereas competitive culture was effective on quantitative indicators (i.e., number of publications and number of citations), only innovative team culture affected the indicators related to effectiveness (i.e., article impact level and citation impact level).     

Stickers to Facts,Imposers, Democracy Advocators,and Committed Impartialists: Preservice Science Teachers’ Beliefs About Teacher’s Roles in Socioscientific Discourses

For science teachers using the discourse of socioscientific issues (SSI), it is important to make a decision as to whether when and how to disclose their own positions. The existing limited literature shows that science teachers prefer one of four roles during SSI discourse: sticker to facts, imposer, democracy advocator, and committed impartialist. The purpose of the present research is to understand the nature of preservice science teachers’ (PST) beliefs underlying such selection. Based on existing literature, we developed a teacher’s belief questionnaire including vignettes representing four teacher’s roles in discussion of genetically modified (GM) foods. Three hundred twenty-four (324) PSTs from a Turkish context experiencing SSI-based reforms completed these questionnaires, selected one of the teacher’s roles, and justified their selection by writing reasons. Content analysis procedures were used in data analysis of this qualitative study. The results show that most PSTs selected dialogical roles (democracy advocators and committed impartialists). Looking at their beliefs, epistemologies and teaching goals work together in PSTs’ selection of their preferred role. In addition, we argue that there is no desired alignment between teachers’ existing beliefs and expectations of SSI reforms. We conclude by indicating certain implications that may enhance such alignment.