1,721,122 research outputs found
Neuropeptide as a new diagnostic and therapeutic target for Alzheimer’s disease
No full texthttps://archives.kaist.ac.kr/eng/research.jsp?year=2023&view=view02아밀로이드 가설에 따르면 아밀로이드 베타 단백질의 비정상적인 침적은 신경세포의 사멸을 일으킨다. 아밀로이드 베타 응집체는 섬유화를 거쳐 노인성 플라크의 대부분을 차지하는데, 최근 연구에 따르면 특히 알츠하이머 환자의 플라크에서 고농도의 전이 금속이 검출된다. 이는 금속 이온과 아밀로이드 베타 간의 긴밀한 상호작용 가능성을 시사한다. 금속 이온은 아밀로이드 베타와 상호 작용해 단백질의 섬유화를 촉진하며, 특히 산화환원 활성 전이 금속인 구리의 경우에는 활성 산소를 다량 생성해 세포 소기관에 심각한 산화 스트레스를 일으킬 수 있다. 아밀로이드 베타 단백질과 전이 금속은 시냅스(신경세포 접합부)에서 신경전달물질과 밀접하게 상호작용할 수 있으나, 아직 이러한 병적 요인들이 신경전달물질의 구조 및 신호전달 기능에 직접적으로 미치는 영향은 자세히 연구된 바 없다. 본 연구에서는 알츠하이머병 발병 기전 내 신경전달물질의 구조 및 기능 변화에 관련된 새로운 역할을 규명하였다. 알츠하이머의 발병 요소로 여겨지는 구리 이온, 아밀로이드 베타, 금속-아밀로이드 베타 복합체는 소마토스타틴의 자가 응집을 유도했다. 생성된 소마토스타틴 응집체는 수용체에 더이상 결합할 수 없는 것을 증명하였으며, 이는 신경전달물질로서의 본연의 역할을 잃은 것으로 해석되었다 (loss-of-function). 더 나아가, 소마토스타틴 자체 또한 금속의 유무에 따라 아밀로이드 베타의 응집 경로를 바꾸고 독성 개선 효과를 보였다. 본 연구 결과는 알츠하이머 질환의 발병 기전 내 신경전달물질의 새로운 역할을 최초로 제안하였고, 노화에 의한 신경퇴행성 질환의 병적 네트워크를 규명하는 데에 실마리를 제공하였고, 향후 바이오마커 및 치료제 개발에도 크게 기여할 것으로 기대된다The research article reports the new discovery that the native neuropeptide somatostatin (SST) undergoes conformational and functional changes in the presence of copper ions, metal-free amyloid-β (Aβ), and metal-bound Aβ (metal-Aβ), which are pathological factors found in the brains of patients with Alzheimer’s disease. These pathological elements induce the self-assembly of SST and, consequently, prevent it from binding to receptors. In the reverse direction, SST notably modifies the aggregation profiles of Aβ species in the presence of metal ions, attenuating their cytotoxicity and interactions with cell membranes. These overall findings demonstrate a loss of SST’s normal functions as a neurotransmitter and a gain in its modulative function against metal-Aβ under pathological conditions.한국과학기술원 : 화학
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
Reduction of ammonia accumulation and improvement of cell viability by expression of urea cycle enzymes in Chinese hamster ovary cells
No full textPreviously, we developed a CHO cell line (CHO-OTC1-A19) that expresses the first two enzymes in the urea cycle and exhibits a higher ammonia-removing ability and faster growth rate than a vector-controlled CHO cell line (CHO-neo-5). The current study was undertaken to develop a cell line with an ammonia-removing ability higher than the cell line developed previously. To accomplish this, CHO cell lines expressing the first three, first four, or all five enzymes of the urea cycle were constructed using a stable transfection method. Finally, the CHO-AS-16, CHO-AL-19, and CHO-Arg-11 cell lines expressing the first three, first four, and all five enzymes of the urea cycle, respectively, were selected and found to exhibit higher ammonia-removing ability than the CHO-OTC1-A19 cell line. Among the three selected cell lines, CHO-AL-19 showed the highest ammonia-removing ability and highest cell viability at a higher cell density, with 40% and 15% lower ammonia concentration in the culture media than that of CHO-neo-5 and CHO-OTC1-A19 cell lines, respectively. CHO-AL-19 also showed 44% and 10% higher cell viability than the CHO-neo-5 and CHO-OTC1-A19 cell lines, at a higher cell density, respectively. The ammonia concentrations in the culture media were expressed as the ammonia concentration/cell, and the CHO-AL-19 cells revealed 45-60% and 20% lower ammonia concentration/cell than the CHO-neo-5 and CHO-OTC1-A19 cells, respectively
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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