1,721,203 research outputs found
Cloning, Expression, and Characterization of Two β-Glucosidases from Isoflavone Glycoside-Hydrolyzing Bacillus subtilis natto
No full textSupplemental material for Polynomial regression with heteroscedastic measurement errors in both axes: Estimation and hypothesis testing
No full textSupplemental material for Polynomial regression with heteroscedastic measurement errors in both axes: Estimation and hypothesis testing by Chi-Lun Cheng, Jia-Ren Tsai and Hans Schneeweiss in Statistical Methods in Medical Research</p
A process for high-efficiency isoflavone deglycosylation using Bacillus subtilis natto NTU-18
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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
eglycosylation of isoflavones by Bacillus subtilis natto NTU-18
No full text本研究由市售納豆產品中篩選分離出一株具有高 β-葡萄糖苷酶活性並且能高效率地將帶醣基之大豆異黃酮進行去醣基化之納豆菌 Bacillus subtilis natto NTU-18。將此納豆菌於 5% 黑豆奶中進行批式培養，發現 β-葡萄糖苷酶活性於第 8 小時開始測得，並於第12小時達到最高，且酵素活性位於菌體之表面。第 24 小時培養基中所含具醣基大豆異黃酮 daidzin 與 genistin 分別有 100% 與 75% 成功的被去醣基化。與去醣基化進行之同時，發酵液呈現對 CHO-K1 雌激素受體 ERβ 高結合度、ERα 低結合度之功效。關於納豆菌之 β-葡萄糖苷酶性質探討，我們進一步的經由比對枯草桿菌 Bacillus subtilis 168，由此納豆菌株中選殖出四種可能具 β-葡萄糖苷酶序列的基因 (bglA, bglH, yckE 和 ydhP)，並分別表現於 E. coli M15 中進行 β-葡萄糖苷酶重組蛋白質特性之研究。經由胺基酸序列分析比對，此四種 β-葡萄糖苷酶 (BglA, BglH, YckE 和YdhP) 均屬於 BGA-subfamily。在我們所使用的基質測定中，表現的重組蛋白質以 BglH 與 YckE 具有β-葡萄糖苷酶的活性，而另兩者則無。在重組β-葡萄糖苷酶 BglH 和YckE的特性研究，當以p-nitrophenyl-β-D-glucoside 為基質，兩者最適反應溫度均介於 37-45 °C， 而 BglH 比 YckE 有更高的耐熱安定性。兩者最適反應 pH 均為 6.0，而 YckE 比 BglH 有較廣的 pH 安定性 (pH 6.0-9.0)。在金屬離子抑制活性方面，當重組 BglH 分別與1 mM Cd2+、Fe2+ 和Cu2+ 作用後其活性分別下降了 73%、63% 和 43%，當與其它二價金屬離子 (Ca2+, Mg2+ 和 Mn2+) 作用後，其活性大約下降 0-23%；而重組 YckE與前述二價金屬離子作用後其活性下降幅度均小於20%。在我們所測試的基質中，重組 BglH 與重組 YckE 分別與 genistin 和 p-nitrophenyl-β-D-fructopyranoside 有最高的親和性。而此二重組蛋白質均具有將帶醣基的大豆異黃酮 daidzin 和 genistin 進行去醣基化的能力，其中以重組 BglH 之去醣基效率較佳。將 B. subtilis homo-BglH 培養於5%豆粕培養基中，在第9小時到第12小時其對大豆異黃酮的轉化率較其他三株基因突變者低。我們認為，B. subtilis 中的 BglH 在大豆異黃酮去醣基過程中可能扮演著重要的角色。本研究之主要目的在建立一個高效率的大豆異黃酮去醣基的轉化生產程序，考慮 β-葡萄糖苷酶活性存在位置，以及納豆菌生長快速之特性。本研究嘗試結合菌體培養、β-葡萄糖苷酶活性誘導以及大豆異黃酮連續轉化之程序於一體，亦即發展菌體在批次培養後，以一次或連續饋料的方式在液態培養過程中添加含醣基的大豆異黃酮抽出物進行基質去醣基化反應。結果顯示，在批次培養中，當起始培養液中所添加的帶醣基大豆異黃酮濃度太高會抑制納豆菌的生長，延長菌體於遲滯期的時間。在連續饋料培養中，先將納豆菌培養於 2 L 的 5% 豆粕培養基 8 小時後，開始饋入帶醣基大豆異黃酮溶液(daidzin 與 genistin 濃度分別為 3.0 mg/mL 與 1.0 mg/mL)，當饋料流速控制於 1.5 mL/min，總饋入體積為 3 L，有最佳的去醣基轉化率，在第 42 小時 daidzin 和 genistin 被轉化率分別為 97.7% 和 94.6%，發酵液所含 daidzein 和 genistein 濃度可達 4228 μM 和 1314 μM，其轉換速率分別為 25.6 mg/L/h 與 8.5 mg/L/h。我們認為這個生產程序可以實際應用於工業量產，而此發酵液則可做為開發選擇性雌激素受器調節劑之用。In this study, strain Bacillus subtilis natto NTU-18 with high isoflavone glycoside-hydrolyzing β-glucosidase activity was isolated from commercial natto product. During the batch fermentation of 5% black soymilk by B. subtilis natto NTU-18, the activity of β-glucosidase appeared at 8 h after inoculation and reached maximum (3.3 U/ml) at 12-h, and the β-glucosidase was found cell associated. Deglycosylation of isoflavone glycosides was observed at the same period, the deglycosylation rate of daidzin and genistin at 24-h was 100 % and 75%, respectively. In accordance with the deglycosylation of isoflavone glycosides, the estrogenic activity of the 24-h fermented black soymilk broth bind to and induce transcription of hERβ to a higher extent than of hERα. To clinically important issues, the ERα is highly expressed in breast and uterine tissue and the ERβ refers to such as bone stability and cardiovascular health. The biochemical properties of β-glucosidases in Bacillus subtili natto NTU-18 were studied basing on the genomic sequence of Bacillus subtilis 168, four β-glucosidase genes (bglA, bglH, yckE and ydhP) from B. subtilis natto NTU-18 were cloned and the characteristics of the recombinant enzymes expressed in E. coli were investigated. Compare the amino acid sequences, these four β-glucosidases belonged to the BGA subfamily. The recombinant protein of BglH and YckE showed β-glucosidase activity using substrates of used, and another two did not. In the biochemical properties of recombinant β-glucosidases BglH and YckE, the optimal temperature for p-nitrophenyl-β-D-glucoside (pNPG) hydrolyzing activity of both enzymes was between 37 and 45 °C, but BglH had a higher thermal stability than that of YckE. Both showed high activity at pH 6.0, but YckE was stable over a wider pH range than that of BglH (pH 6.0-9.0). Activities of recombinant BglH was inhibited 73%, 63%, and 43% by 1.0 mM Cd2+, Fe2+, or Cu2+, respectively, while other divalent metal ions (Ca2+, Mg2+ and Mn2+) resulted in 0-23% inhibition, whereas YckE was inhibited by less than 20% by any of the divalent metal ions we tested. Among the substrate we used, BglH showed the highest affinity for genistin and YckE showed the highest affinity for p-nitrophenyl-β-D-fructopyranoside (pNPF). Both BglH and YckE hydrolyzed genistin and daidzin into their isoflavone aglycones, genistein and daidzein, but BglH was more efficient than YckE in isoflavone glucoside hydrolysis (20-fold higher kcat). The insertion mutant strain B. subtilis homo-BglH showed lower isoflavone deglycosylation rate than other gene mutant strains during 9-h to 12-h in 5% defatted-soy medium fermentation. According to these results, BglH may play a more important role than others in the deglycosylation of isoflavone glucosides in B. subtilis natto during fermentation. Main of this study is to establish a highly efficient isoflavone deglycosylation process. In batch fermentation, high concentration soy isoflavone glucosides (SIG) of the initial culture medium inhibited the growth of B. subtilis natto. In a continuous feeding process (the feeding rate 1.5 mL/min) and totally 3 L of soy isoflavone glucosides (SIG) solution (daidzin 3.0 mg/mL and genistin 1.0 mg/mL) was to be fed into after 8 h of batch fermentation at the beginning contained 2 L of 5% defatted-soy medium inoculated with B. subtilis natto NTU-18, our results showed the highest isoflavones deglycosylation rate of daidzin and genistin (97.7% and 94.6%, respectively). The maximum concentration of daidzein and genistein in broth reached 4227.8 μM and 1314.3 μM, respectively, and the productivity of daidzein and genistein was 25.6 mg/L/h and 8.5 mg/L/h, respectively, during 42 h of fermentation. This process showed that it is an efficient bioconversion process for continuously production of selective estrogen receptor modulator (SERM).口試委員會審定書.......................................I謝...................................................II文摘要...............................................IIIbstract...............................................Vist of abbreviation and full name.....................VIIilingual terminology glossary.........................IXist of tables.........................................XIIIist of figures........................................XVhapter I Literature review............................11.1 A summary of isoflavones..................21.2 Deglycosylation of isoflavone.............131.3 Bacillus subtilis natto...................141.4 β-Glucosidase.............................171.5 The objective of this research............20hapter II Selection and cultures of B. subtilis natto strain......................................222.1 Introduction..............................232.2 Materials and methods.....................242.3 Results...................................292.4 Discussion................................44hapter III Cloning and expression the β-glucosidase genes from B. subtilis natto NTU-18..............483.1 Introduction..............................493.2 Materials and methods.....................503.3 Results...................................713.4 Discussion................................114hapter IV A bioprocess for high-efficiency isoflavone deglycosylation by B. subtilis natto........1174.1 Introduction..............................1184.2 Materials and methods.....................1204.3 Results...................................1224.4 Discussion................................139hapter V Summary and Perspective......................1445.1 Summary...................................1455.2 Perspective...............................148ist of References.....................................150ommonly used reagents.................................17
Integration of Panorama Image and Laser Scanning to Build Large-Scale Virtual Reality Models
No full text本研究整合環場影像及雷射掃描技術建構出大尺度之虛擬實境 (Virtual Reality, VR) 模型。相對於傳統虛擬實境之建構多為小尺度，本研究所發展的方法可構建大範圍空間尺度之虛擬實境模型—如擁有數十棟建築物之校園環境—且具有真實環境影像之貼圖材質。建構過程主要分為三個步驟：空間資訊擷取、三維模型建立及多場景接合。空間資訊擷取的過程中，藉由安排所獲取之資訊，可降低模型建立的複雜度，達成近即時運算之場景建模系統；單一場景資訊擷取所需時間約為12分鐘。三維虛擬模型的建立的步驟係利用空間資訊排列之規則將模型網格化，並配合Delaunay Triangulation 最佳化網格點並減量至60%，再利用環場影像於邊界條件上與模型具一致性之特點，簡化影像材質之對應。在多場景接合的方法上，本研究發展一套全域性接合方法，將三維空間資料簡化為二維資訊，並進行資料點擴展及型態分析，以提高接合正確率。以此接合方法於454.9公尺之長距離進行地圖重建實驗，誤差為0.1%。接合正確率與空間環境複雜度相關，實驗於具有規則特徵的環境，如具有規則牆面之臺大體育館，在平均距離46.7公尺，標準差8.9公尺的條件下，接合正確率可達100%。而在較複雜之環境，如臺大椰林大道之多植栽環境，在平均距離44.9公尺，標準差5.8公尺條件下，接合正確率則降為72％。若應用此接合方法於長寬十數公尺之室內環境，亦能正確接合。相對於傳統之迭代最近點算法 (Iterative Closest Point, ICP)，此接合法不需初始估測值，且在5分鐘內可完成計算，若給予估測值則約能在10秒內完成。本研究所發展的方法將可應用於模型重建、環境導覽及都市開發規劃等諸多應用。This research proposes a method to reconstruct real-world objects in large-scale virtual reality by integrating the information from panoramic images and data acquired with a laser range sensor. Compared with most virtual reality applications, the proposed method is capable of building large-scale virtual reality models such as a campus environment including many buildings, and the reconstructed building''s appearance is photorealistic. The procedure for building the virtual reality models mainly consists of three phases: the acquisition of the space information, reconstruction of 3D model, and integration of multiple scenes to form a large-scale virtual reality model. In the first phase of data acquisition, the complexity of the model reconstruction is reduced by properly arranging the acquired point cloud data. Therefore, the reconstruction of the 3D model is nearly real time. The time required to acquire the 3D point cloud data for a single scene was about 12 minutes. The reconstruction of 3D virtual reality model utilizes the well organized collected spatial data for meshing which also applies Delaunay triangulation for a data reduction to 60%. The texture mapping process is also simplified based on the correspondence of boundary conditions in the panorama image and the 3D model. Moreover, a global registration method was developed. It initially coverts the 3D spatial data into 2D information and then applies spatial propagation and shape analysis filters for enhancing the matching probability. When applying this method on a reconstruction of a map 454.9 meters in length, the error was 0.1%. The matching probability is affected by the complexity of environment to be reconstructed. When applying the method on an environment with regular features, such as the NTU gymnasium with mostly regular wall surfaces and with an average scanning distance of 46.8m and standard deviation of 8.8m, the matching probability was 100%. In a separate experiment for a more complex environment such as the NTU Royal Palm Blvd. with many trees and irregular structures, the matching probability decreases to 72%. The method was also successfully applied for the reconstruction of an indoor environment which is ten meters in width and height. Comparing with the iterative closest point (ICP) method, our approach has the advantage that it does not require initial guess for the registration of multiple scenes. The registration process can be accomplished in 5 minutes. Moreover, it can be completed in 10 seconds if the initial guess is given. The developed method can be used in various applications such as model reconstruction, tour guiding, and the city planning.致謝 i要 iibstract iiiist of Figures ixist of Tables xvihapter 1 Introduction 1.1 Preface 1.2 Objectives 2.3 Thesis Organization 3hapter 2 Literature Review 4.1 Virtual Reality (VR) 4.2 Geography Information System (GIS) 5.2.1 Features of GIS 7.2.2 Formats of GIS 8.2.3 Functions of GIS 9.2.4 Web GIS 10.2.5 VR GIS 10.3 3D Space Reconstruction 11.3.1 Stereo Vision 11.3.2 Range Sensor 15.3.3 Multi Sensors 18.3.4 Data Reduction 19.4 Registration 20hapter 3 Materials and Methods 23.1 System Architecture 23.1.1 Hardware 23.1.2 Software 24.2 Single Scene Reconstruction 27.2.1 Spatial Data Acquisition 28.2.2 Coordinate Transformation 31.2.3 Surface Reconstruction 32.2.4 Texture Mapping 36.3 Multiple Scene Registration 38.3.1 Sampling 39.3.2 Preprocess 42.3.3 Registration 48.4 Visualization 49hapter 4 Result and Discussion 50.1 Virtual Reality Software 50.2 Single Scene Reconstruction 52.2.1 Data acquisition 52.2.2 Coordinate Transformation 53.2.3 Surface Reconstruction 54.2.4 Texture Mapping 58.2.5 Data Reduction 60.3 Multiple Scenes Registration 63.3.1 Preprocess 63.3.2 Comparing to Iterative Closest Point (ICP) Method 76.3.3 Large Scale Issue 88.4 Cases Demonstration 92hapter 5 Conclusions and Suggestions 104.1 Conclusions 104.2 Suggestions 105eferences 10
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
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