28 research outputs found

    Scale development for pre-service mathematics teachers’ perceptions related to their pedagogical content knowledge

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    The purpose of this study is to develop a scale to determine pre-service mathematics teachers’ perceptions related to their pedagogical content knowledge. Firstly, a preliminary perception scale of pedagogical content knowledge was constructed and then administered to 112 pre-service mathematics teachers who were enrolled in a mathematics teacher education programme. Exploratory and confirmatory factor analysis, item analysis, correlation analysis, internal consistency and descriptive statistic techniques were used to analyse the data. Then validity and reliability of the scale were investigated. The analyses resulted in the development of a five-factor scale of 17 items that was proved valid and reliable. We contend that the scale developed has the merit to contribute to pre-service teachers’ self-awareness by revealing their perceptions regarding their pedagogical content knowledge.Keywords: pedagogical content knowledge, pre-service mathematics teachers,scale developmen

    Both Positive and Negative Selection Pressures Contribute to the Polymorphism Pattern of the Duplicated Human CYP21A2 Gene.

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    The human steroid 21-hydroxylase gene (CYP21A2) participates in cortisol and aldosterone biosynthesis, and resides together with its paralogous (duplicated) pseudogene in a multiallelic copy number variation (CNV), called RCCX CNV. Concerted evolution caused by non-allelic gene conversion has been described in great ape CYP21 genes, and the same conversion activity is responsible for a serious genetic disorder of CYP21A2, congenital adrenal hyperplasia (CAH). In the current study, 33 CYP21A2 haplotype variants encoding 6 protein variants were determined from a European population. CYP21A2 was shown to be one of the most diverse human genes (HHe=0.949), but the diversity of intron 2 was greater still. Contrary to previous findings, the evolution of intron 2 did not follow concerted evolution, although the remaining part of the gene did. Fixed sites (different fixed alleles of sites in human CYP21 paralogues) significantly accumulated in intron 2, indicating that the excess of fixed sites was connected to the lack of effective non-allelic conversion and concerted evolution. Furthermore, positive selection was presumably focused on intron 2, and possibly associated with the previous genetic features. However, the positive selection detected by several neutrality tests was discerned along the whole gene. In addition, the clear signature of negative selection was observed in the coding sequence. The maintenance of the CYP21 enzyme function is critical, and could lead to negative selection, whereas the presumed gene regulation altering steroid hormone levels via intron 2 might help fast adaptation, which broadly characterizes the genes of human CNVs responding to the environment

    PREVALENCE AND RISK FACTORS FOR GALL BLADDER POLYPS

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    ABSTRACTObjective: Polyps of gallbladder are tumour-like lesions of this organ. Little has been known aboutfactors associated with the occurrence of gallbladder polyps. We aimed to examine prevalence andfactors associated with gallbladder polyps in our region.Design: Prospective clinical study.Setting: Kocaeli University Teaching Hospital.Subjects: Four hundred and thirty two patients were enrolled to the study.Interventions: Subjects were screened for the presence of any pathological condition for gallbladderby upper abdominal ultrasonography completed a questionnaire, and underwent a physicalexamination and blood chemistry tests.Results: Family history of gastrointestinal disease, gallbladder disease and any neoplastic diseaseand abnormality in HDL-cholesterol levels had most consistent association at univariate analysis.Multivariate logistic regression analysis showed that family history of any gastrointestinal diseaseand abnormalities of HDL-cholesterol levels were significant.Conclusions: Our findings suggest the formation of gallbladder polyps is associated with fatmetabolism. Other unknown factors may also influence the formation of this lesion. Relationshipbetween gallbladder polyps and family history of some diseases suggests us to perform somegenetic studies

    Anticancer and antimetastatic activity of Hypomyces chrysospermus, a cosmopolitan parasite in different human cancer cells.

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    The importance of microbial natural compounds in drug research is increasing every year and they are used to prevent or treat a variety of diseases. Hypomyces chrysospermus is a cosmopolitan parasite of many Boletaceae members. Since not much work has been conducted to date, this study is undertaken to explore the anticancer effect, including the antiproliferative and antimetastatic activity of Hypomyces chrysospermus. The aim of this study is to determine the antiproliferative and antimetastatic activity of Hypomyces chrysospermus ethyl acetate extract, having antioxidant activity, against A549, Caco2, MCF-7 human cancer and CCD-19 Lu and CCD 841 CoN healthy human cell lines. Firstly, cytotoxic activity was determined by the WST-1 assay. After cell proliferations and anti-metastatic effects were investigated by a real-time cell analysis system (RTCA-DP) and IC(50) concentrations were calculated for each cell line. In addition, the expression levels of Apaf-1, TNF and NF-kB mRNA in cancer cells were investigated with RealTime-PCR. The ethyl acetate extract of Hypomyces chrysospermus presented anticancer activities including antiproliferative and antimetastatic effects. Hypomyces chrysospermus as a source of biologically active metabolites can be used as an important resource in the development of new anticancer effective agents

    How does pregnancy affect the patients with pituitary adenomas: a study on 113 pregnancies from Turkey

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    Objective Data regarding pregnancies in relation to pituitary tumors are limited. The effects of pregnancy on pituitary adenomas and the effects of adenoma itself (hormonal activity, mass effects and pituitary insufficiency) and/or treatment on the ongoing gestation and developing fetus were evaluated

    The acromegaly registry of ten different centers in Turkey.

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    OBJECTIVES: To describe biochemical and clinical features, and therapeutic outcomes of acromegaly patients in Turkey. METHODS: Retrospective multicenter epidemiological study of 547 patients followed in 10 centers of the Turkish Acromegaly registry. RESULTS: A total of 547 acromegaly patients (55% female) with a median age of 41 was included in this study. Majority of patients had a macroadenoma (78%). Transsphenoidal surgery was performed as primary treatment in 92% of the patients (n = 503). Surgical remission rate was 39% (197/503) in all operated patients. Overall disease control was achieved in 70% of patients. Remission group were significantly older than non-remission group (p = .002). Patients with microadenomas had significantly higher remission rates than patients with macroadenomas (p < .001). Patients with microadenomas were significantly older at the time of diagnosis when compared to patients with macroadenomas (p < .001). Preoperative growth hormone (GH) and insulin-like growth factor 1 (IGF-1) levels were significantly lower in the remission group (p < .001). Initial IGF-1 and GH levels were significantly higher in macroadenomas compared to microadenomas (p < .001). Medical treatment was administered as a second-line treatment (97%) in almost all patients without remission. Radiotherapy was preferred in 21% of the patients mostly as a third line treatment. CONCLUSIONS: This is one of the largest real life studies evaluating the epidemiological characteristics and treatment outcomes of patients with acromegaly who were followed in different centers in Turkey. Transsphenoidal surgery in the treatment of acromegaly still remains the most valid method. Medical treatment options may improve long-term disease outcomes in patients who cannot be controlled with surgical treatment (up to 70%)
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