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Chang chang chang
No full textLive recording.Electronic reproduction from Rulan Chao Pian Audio Cassette Collection.Performers: 卞趙如蘭.Sung in Chinese.Performers: Bian Zhao Rulan
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Avenaciolides, secondary metabolites from indigenous fungus Neosartorya fischeri, on inhibiting methicillin-resistant Staphylococcus aureus (MRSA)
No full text在現代醫學中，抗生素的發展及其應用在許多成功的感染治療中一直扮演著舉足輕重的角色。然而，隨著幾十年來抗生素的濫用，使抗藥性菌株不斷地增長，進而使現今醫學可運用的抗生素漸漸趨少。舉例來說，在革蘭氏陽性抗藥菌株中，抗甲氧西林金黃色葡萄球菌(MRSA)位於院內交叉感染率及死亡率之首。在此抗生素後世代，新藥的尋找及發展成為了現今刻不容緩的課題。 在本論文的研究中，我們發現一株來自於花蓮縣的本土真菌「Neosartorya fischeri」會分泌一種二級代謝產物並有效的抑制抗甲氧西林金黃色葡萄球菌的生長。本篇研究利用以活性為導向的策略，純化且分離出一系列的燕麥麯黴素衍生物。在穿透式電子顯微鏡研究中，發現其中有三個燕麥麯黴素衍生物藉由抑制細菌細胞壁合成來達成其抑菌之活性。藉由「結構-活性」關係中，我們發現在燕麥麯黴素衍生物上的a，b-共振不飽和羰基是抑菌活性中不可或缺的單元。因此，在經過進一步的文獻搜索以及核磁共振磷谱和質譜的分析中，證實了燕麥麯黴素抑制細胞壁合成的第一步酵素「乙醯氨基葡萄糖轉移酶」。雖然，目前臨床中以磷黴素為乙醯氨基葡萄糖轉移酶之唯一抑制劑；但近年來，抗磷黴素突變菌株卻不斷地被發現及報導。其最嚴重的抗磷黴素機轉，為乙醯氨基葡萄糖轉移酶之催化中心的胺基酸突變(半胱氨酸突變成天門冬氨酸)。 在此研究中，一號與二號燕麥麯黴素衍生物不僅針對野生性也針對抗磷黴素(半胱氨酸突變成天門冬氨酸)之乙醯氨基葡萄糖轉移酶有抑制活性。並在經由分子模擬計算，我們推論出二號化合物競爭性地阻擾酵素受質中間體的產生。最後，在所有衍生物中，二號燕麥麯黴素被證實具為有潛力之先驅化合物，可作為未來發展且抑制抗甲氧西林金黃色葡萄球菌及抗磷黴素之乙醯氨基葡萄糖轉移酶突變的指標性藥物。Antibiotics, the major breakthrough of modern medicine, play a pivotal role in many successful medical practices. However, the emergence of resistant traits against multiple classes of antibiotics has progressively narrowed the available treatment options for some pathogens for decades. Among the Gram-positive drug resistant microbes, methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen responsible for nosocomial and community-acquired bacterial infections around the world. Since we are now living in the post-antibiotics era in which the crisis of antimicrobial resistance is worse than ever before, discovering alternative antibiotics is urgent to counteract the ever increasing phenomenon. In this study, we report four avenaciolide derivatives (1-4) isolated from Neosartorya fischeri, an indigenous fungus from Hualien, Taiwan, three of which had significant antimicrobial activity against MRSA. Based on the TEM results, the morphology of avenaciolide-treated cells was protoplast-like, which indicated that cell wall biosynthesis was interrupted. Comparing the structures and MICs of 1-4, the the a,b-unsaturated carbonyl group seems to be an indispensable moiety for antimicrobial activity. Based on a structural similarity survey of other inhibitors with the same moiety, we revealed that MurA was the drug target. This conclusion was validated by 31P NMR spectroscopy and MS/MS analysis. Although fosfomycin, which is the only clinically used MurA-targeted antibiotic, is ineffective for treating bacteria harboring the catalytically important Cys-to-Asp mutation, avenaciolides 1 and 2 inhibited not only wild type but also fosfomycin-resistant MurA in an unprecedented way. Molecular simulation revealed that 2 competitively perturbs the formation of the tetrahedral intermediate in MurA. Our findings demonstrated that 2 is a potent inhibitor of MRSA and fosfomycin-resistant MurA, laying the foundation for the development of new scaffolds for MurA-targeted antibiotics
Variations on the Author
Get PDF“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
Get PDFWe 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
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