1,722,741 research outputs found
Yu, Su-kyong
No full text학위논문(석사)--아주대학교 일반대학원 일반대학원 :의학과,2007. 8목적: 만성 신장질환 환자에서 여러 가지 무기질 대사의 장애가 초래된다는 것은 널리 알려진 사실이다. 국내에는 신대체요법을 시행받고 있는 말기 신부전 환자에서 이차성 부갑상선기능항진증에 관한 연구는 많이 이루어지고 있으나, 만성 신장질환의 초기 단계에서의 부갑상선 호르몬과 비타민 D에 관한 자료는 거의 없는 실정이다. 본 연구에서는 신대체요법을 시행받지 않고 있는 만성 신장질환 환자에서 사구체 여과율에 따른 부갑상선호르몬과 비타민 D의 변화 및 기타 무기질 대사 관련 물질과의 연관성을 조사하고자 한다.
방법: 2006년 5월부터 2007년 4월까지 아주대학교 병원에서 이전에 비타민 D 제제를 복용한 경험이 없으며 신대체요법을 받지 않은 환자들 중 MDRD (Modification of Diet in Renal Disease study) 공식을 이용하여 계산한 사구체 여과율이 60 mL/min/1.73 m2 미만인 환자를 대상으로 연구를 시행하였다. 사구체 여과율을 기준으로 만성 신장질환(Chronic Kidney Disease, CKD) 단계 3, 4, 5에 해당되는 환자에서 혈청 부갑상선호르몬, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, 혈청 칼슘 및 인 등을 측정하여 평균을 구하였으며 이차성 부갑상선기능항진증과 비타민 D 결핍의 유병율 및 사구체 여과율과 혈청 칼슘, 인, 부갑상선호르몬, 비타민 D와의 연관성을 알아보았다.
결과: 총 113명의 환자 중 만성 신장질환 3단계 환자는 32명, 4단계 환자는 37명, 5단계 환자는 44명이었으며 평균 혈청 부갑상선호르몬은 만성 신장질환 3단계에서 81.9 ± 58.5 pg/mL, 4단계에서 148.0 ± 139.5 pg/mL, 5단계에서 315.0 ± 208.3 pg/mL 였다. 부갑상선기능항진증 (intact PTH>65 pg/mL)의 유병율은 각 단계별로 56.3% (18/32예), 70.3% (26/37예), 95.5% (42/44예)로 나타났다. 혈청 25-hydroxyvitamin D가 15 ng/mL 미만인 예는 만성 신장질환 3단계에서 86.2% (25/29예), 4단계에서 75.7% (28/37예), 5단계에서 88.4% (38/43예)로 나타났다. 또한 혈청 1,25-dihydroxyvitamin D가 25 pg/mL 미만인 예는 만성 신장질환 3단계에서 22.7% (5/22예), 4단계에서 50.0% (6/12예), 5단계에서 62.5% (10/16예)로 나타났다. 사구체 여과율과 혈청 칼슘, 인, 부갑상선호르몬, 비타민 D와의 상관관계 분석에서 사구체 여과율은 혈청 부갑상선호르몬(r=-0.531, P=0.000), 혈청 인 (r=-0.357, P=0.000), alkaline phosphatase (r=-0.214, P=0.023)와 음의 상관관계를 보였고, 1,25-dihydroxyvitamin D (r=0.587, P=0.000), 혈청 칼슘 (r=0.459, P=0.000)과는 양의 상관관계를 보였다. 사구체 여과율과 25-hydroxyvitamin D (r=0.095, P=0.326)는 의미있는 상관관계를 보이지 않았다.
결론: 이차성 부갑상선기능항진증 및 비타민 D 결핍은 만성 신장질환의 조기 단계에서부터 시작됨을 알 수 있었다. 국내에서 신대체요법 시행 전의 만성 신장질환 환자에서 사구체 여과율의 저하에 따른 부갑상호르몬과 비타민 D의 변화를 수치화한 최초의 연구이며, 앞으로 보다 많은 환자를 대상으로 한 전향적인 연구가 필요할 것으로 사료된다. 또한 만성 신장질환 1단계와 2단계에서도 이러한 연구가 필요할 것으로 생각된다.Ⅰ. 서론 = 1
Ⅱ. 연구대상 및 방법 = 4
A. 대상 환자군의 설정 = 4
B. 연구 방법 = 4
C. 통계 분석 = 5
Ⅲ. 결과 = 6
Ⅳ. 고찰 = 15
Ⅴ. 결론 = 20
참고문헌 = 21
ABSTRACT = 24MasterBackgrounds: Disturbances of mineral metabolism are common during the course of chronic kidney disease (CKD) and lead to serious and debilitating complications unless these abnormalities are addressed and treated. While secondary hyperparathyroidism develops during the early stages of chronic kidney disease, few patients are evaluated for elevations in serum parathyroid hormone (PTH) before they become frankly hypocalcemic. Quantification of the prevalence of these abnormalities has not been described using current assays in patients with non-dialysed chronic kidney disease in Korea.
Materials and methods: Patients who had documented eGFR<60 mL/min/1.73 m2 and non-dialysed and had not received any vitamin D compounds. eGFR was calculated by simplified MDRD (Modification of Diet in Renal Disease study) equation. Blood samples were collected for serum creatinine, calcium, phosphate, intact PTH, 25-hydroxyvitamin D (25(OH)D3) and 1,25-dihydroxyvitamin D (1,25(OH)2D3) between May 2006 and April 2007.
Results: There were 32 patients with CKD stage 3 (30-59 mL/min/1.73 m2), 37 with CKD stage 4 (15-29 mL/min/1.73 m2) and 44 with CKD stage 5 (65 pg/mL) was 56.3% (18/32) in stage 3, 70.3% (26/37) in stage 4 and 95.5% (42/44) in stage 5 patients. The prevalence of 25-hydroxyvitamin D deficiency (25(OH)D3<15 ng/mL) was 86.2% (25/29) in stage 3, 75.7% (28/37) in stage 4 and 88.4% (38/43) in stage 5. The prevalence of 1,25-dihydroxyvitamin D (1,25(OH)2D3)<25 pg/mL) was 22.7% (5/22) in stage 3, 50.0% (6/12) in stage 4 and 62.5% (10/16) in stage 5. Correlation analysis indicated that there was a negative correlation between eGFR and intact PTH (r=-0.531, P=0.000) and a positive correlation between eGFR and 1,25-dihydroxyvitamin D (r=0.587, P=0.000).
Conclusions: These data indicate that vitamin D deficiency and abnormality of parathyroid hormone are prevalent even in the early stage of chronic kidney disease. There are significant correlations of eGFR with intact PTH, 1,25-dihydroxyvitamin D but no correlation between eGFR and 25-hydroxyvitamin D. In non-dialysed CKD patients, quantification of the prevalence of abnormality of intact PTH and vitamin D deficiency has been described in this study in Korea. Future research should be conducted in a prospective, multi-center community cohort study including early stage like CKD 1 and 2
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Streamlining attacks on CAPTCHAs with a computer game
No full textCAPTCHA has been widely deployed by commercial web sites as a security technology for purposes such as anti-spam. A common approach to evaluating the robustness of CAPTCHA is the use of machine learning techniques. Critical to this approach is the acquisition of an adequate set of labeled samples, on which the learning techniques are trained. However, such a sample labeling task is difficult for computers, since the strength of CAPTCHAs stems exactly from the difficulty computers have in recognizing either distorted texts or image contents. Therefore, until now, researchers have to manually label their samples, which is tedious and expensive. In this paper, we present Magic Bullet, a computer game that for the first time turns such sample labeling into a fun experience, and that achieves a labeling accuracy of as high as 98% for free. The game leverages human computation to address a task that cannot be easily automated, and it effectively streamlines the evaluation of CAPTCHAs. The game can also be used for other constructive purposes such as 1) developing better machine learning algorithms for handwriting recognition, and 2) training people's typing skills.</p
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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