Effect of <Emphasis Type="SmallCaps">l</Emphasis>-Thyroxine on Micronuclei Frequency in Peripheral Blood Lymphocytes in Clinical and Experimental Conditions

The aim was to study the genotoxic effect of high concentration of thyroxine (T₄) in vivo in peripheral blood lymphocytes (PBL) of the patients suffering from thyroid disorders. The effect was compared by performing in vitro experiments with addition of increasing concentration of T₄ (0.125–1 µM) in whole blood samples from healthy donors. Cytokinesis-blocked micronuclei (CBMN) assay method was used to assess the DNA damage in the PBL. The study included 104 patients which were grouped as control (n = 49), hyperthyroid (n = 31) and hypothyroid (n = 24). A significant increase in micronuclei (MN) frequency was observed in hyperthyroid patients when compared with the hypothyroid and euthyroid group thereby suggesting increased genotoxicity in hyperthyroidism (p < 0.001). A significant increase in MN frequency was observed at T₄ concentration of 0.5 µM and above when compared to lower T₄ concentrations (0.125 and 0.25 µM) and basal in in vitro experiments (p = 0.000). The results indicate that the T₄ in normal concentration does not exhibit the genotoxic effect, as observed in both the in vivo and in vitro experiments. The toxicity of T₄ increases at and above 0.5 μM concentration in vitro. Therefore acute T₄ overdose should be handled promptly and effectively so as to avoid the possible genotoxic effect of high concentration of T₄ in vivo.     

Infrared Absorption Spectra of Serpentine Cat＇s Eye from Sichuan Province of China

Infrared （IR） absorption spectra and X-ray powder diffraction （XRD） patterrns of sexpenfine cat＇s eye from Sichuan Province have been investigated, and infrared absorption bands of the serpentine have been assigned in this paper. The results indicate that the bands near 3 600 - 3 700 cm^-1 belong to the stretching absorption band VOH, the bands in 948 - 1 100 cm^-1 axe assigned to the stretching vibraling band Usvo, and the bands at 600 570 and 440 cm^-1 respectively belong to the bending vibration band VOH, δMg-O and δSi-O. The serpentine cat＇ s eye includes two types： chrysotile and antigorite. Chrysotile has a sharp and intensive band at 3 688 cm^-1 and a weak band at 3 643 cm^-1 , while antigorite has only one intensive band in the region. At vibration band VSi-O, chrysotile and antigorite have a similar feature at 1 071 cm^-1, but the band at 980 cm^-1 in anfigorite has been split into two bands in chrysotile - a strong one at 1 027 cm^-1 and a weak one at 949 cm^-1. In addition, antigorite has a characteristic bending vibrating band δMg-O at 570 cm^-1. Based on the analysis of the feature of crystal structure, their IR differences axe well explained.     

Vacuum interrupter, high reliability component of distribution switches, circuit breakers and contactors

The use of vacuum interrupters(VIs)as the current interruption component for switches,circuit breakers,reclosers and contactors operating at distribution voltages has escalated since their introduction in the mid-1950’s.This electrical product has developed a dominating position for switching and protecting distribution circuits.VIs are even being introduced into switching products operating at transmission voltages.Among the reasons for the VI’s popularity are its compactness,its range of application,its low cost,its superb electrical and mechanical life and its ease of application.Its major advantage is its well-established reliability.In this paper we show how this reliability has been achieved by design,by mechanical life testing and by electrical performance testing.We introduce the“sealed for life”concept for the VI’s integrity.We discuss this in terms of what is meant by a practical leak rate for VIs with a life of over 30 years.We show that a simple high voltage withstand test is an easy and effective method for monitoring the long-term vacuum integrity.Finally we evaluate the need for routine inspection of this electrical product when it is used in adverse ambient environments.     

Construction of “glocal” (global–local) identity among Israeli graduate students in the USA

Abstract This study focuses on the effect of doctoral and postdoctoral studies at leading research universities in the USA on constructing the academic identity of Israeli students. The findings are based on constant comparative analysis of semi-structured interviews with 27 Fulbright alumni. The results show that while American scientific standards become a model for the Israeli scientists, Israeli culture and identity become much more evident, for better or worse. Several ways of handling these identities were recognized and include: the intertwine method, ordering, and buffering. Further theoretical and practical implications are discussed.     

What drives teacher engagement: a study of different age cohorts

Despite the growing body of research on work engagement, little is known about what drives work engagement among different age cohorts. This study aims to investigate whether engagement varies across age cohorts and examine the job resources that foster teacher engagement. A questionnaire was distributed to 537 teachers who were employed in elementary, lower and upper secondary school. Findings show that work engagement did indeed vary across the diverse age group and is influenced by different resources. In line with previous studies, data revealed that the engagement of younger teachers is driven by the opportunity for development and interaction with colleagues, while older employees appreciate the opportunity to see their competencies acknowledged. What is most noteworthy is the opportunity to design practices and to provide every age group with the appropriate set of motivators.     

Retrospective Integration of Research Conducted on a Multi-Section Educational Psychology Course over a Fifteen-Year Period

This article integrates a series of studies conducted over a 15-year period in a multi-section educational course taught by the same supervising professor and his GTAs . The purpose of each study was to determine whether particular interventions or student characteristics affected performance levels in the course. Over the extended period of research, approximately 6000 undergraduate students, with 25 to 55 students in each of more than 200 sections, participated in a variety of research projects related to student performance in the course. The principal research themes addressed were (1) critical thinking, (2) additional cognitive measures (e.g., initial course knowledge, generic vocabulary), (3) class participation, (4) in-class writing activities, and (5) cooperative learning.     

Sense of Place in Child Care Environments

The exterior design of existing preschool environments is evaluated in the context of contemporary writings by architects focusing on creating designs that nurture children’s emotions. Sense of place research is discussed in relation to young children’s experiences. Findings reveal that the majority of sites included in the study incorporated many physical design elements that create a sense of place for children in preschool environments, including small-scale structures, windows, landscaping, natural wall materials, and thresholds. Recommendations for administrators and directors planning and designing a new or remodeled preschool environment include incorporating features that reflect home-like environments with windows, thresholds, and landscaping.     

Empirische Bildungsforschung in der Kritik – ein Überblick über Themen und Kontroversen

This article overviews the criticism which has been published since about 2001 concerning educational research and the related debates. Discussion contributions are classified into six different topics, four of which are expatiated on in this issue: the topic of (1) education theory, (2) discipline policy, (3) governance theory, and (4) teaching theory. To all these four topics the course of debate is shortly presented regarding criticism and counter criticism, in order to give a view to more articles of this issue. Thus a continuous controversial, partly even polemical discussion is described, which will be proceeded in this issue factually and argumentative.