1,720,963 research outputs found
Synthesis and Characterization of PEG-co-DPA Nanoparticles and Application of Photodynamic Therapy
No full text光動力療法(PDT)是一個有效治療腫瘤的方法，其方法是給予光感藥物後再照光以達到療效。然而，光感藥物有著不溶於水且對腫瘤沒有選擇性的缺點。為了以在腫瘤中的酸性環境為目標，我們使用AIBN為initiator合成了PEGMA-co-DPA這個分子聚合物，並以此聚合物做成了對酸鹼值敏感的奈米粒子來包覆光感藥物-間–四羥基氯苯酚 (m-THPC)。我們使用核磁共振儀及凝膠滲透層析來分析我們合成的分子聚合物，並使用pyrene作為探針來研究酸鹼度對於次分子聚合物形成奈米粒子和其臨界聚合濃度(CAC)的影響。結果顯示在此合成的分子聚合物的臨界聚合酸鹼值在5.8到6.6之間，臨界聚合濃度則是在0.0045%到0.0089%之間。之後我們以oil-in-water的方式製備了包覆m-THPC的奈米粒子，並使用動態光散射儀(DLS)以及穿透式電子顯微鏡(TEM)觀察奈米粒子，發現此奈米粒子為圓形且大小約為132奈米，包覆率為89%。在釋放速率的實驗方面，結果顯示了放置48小時後，此奈米粒子在酸鹼值為5的環境下釋放了58%的藥物，比在酸鹼值為7的環境下的10%還多。另外我們使用HT-29這株細胞來研究此奈米粒子的光動力療法效果。以上這些結果顯示了我們製備的對酸鹼度敏感的奈米粒子有針對腫瘤的潛力。Photodynamic therapy (PDT) is an effective therapy for tumor, which involves the administration of photosensitizers followed by illumination. However, the insolubility and non-targeting are defects of photosensitizers. For targeting the acid environment at tumor site, Poly(ethylene glycol) methacrylate-co-2-(Diisopropylamino) ethyl methacrylate (PEGMA-co-DPA) copolymers were synthesized in the presence of 2,2’-Azobis-isobutyronitrile (AIBN) and then formed pH sensitive nanoparticles to encapsulate a photosensitizer, m-THPC. The characteristic of these copolymers were evaluated by 1H nuclear magnetic resonance and gel permeation chromatography. The pH effect on aggregation/deaggregation and critical aggregation concentration (CAC) of the nanoparticles was studied by using pyrene as a probe. The results showed that the critical aggregation pH (Ph*) of the polymers were from 5.8 to 6.6 and the CAC were from 0.0045 to 0.0089 wt% at pH 7.4. The m-THPC loaded nanoparticles were prepared by oil-in-water. The size and morphology of nanoparticles were observed using dynamic light scattering and transmission electron microscopy. The results indicated that the nanoparticles were sphere and the size was 132 nm. The drug encapsulation efficiency was 89%. The in vitro release profile performed that the release rate of m-THPC at pH 5.0 (58% m-THPC released within 48 hours) was faster than at pH 7.0 (10% m-THPC released within 48 hours). The in vitro PDT efficiency was tested with HT-29 cell line by MTT assay. These findings suggest that the pH sensitive nanoparticles prepared in this study are potential carriers for tumor targeting.目 錄試委員會審定書……….……………………………………………….. i謝………………………………………………………………………...ii文摘要…………………………………………………………….…....iii文摘要………………………………………………………….……. iv. Introduction………………………………………….………….……... 1. Materials and Methods………….……………………………….…...... 5.1 Materials………………………………………………………..….. 6.2. Synthesis of PEGMA-co-DPA……….….……….…………..…… 8.3. Copolymer characterizations……………………………….………8.4. Nanoparticle formation……………………….……………………8.5. Nanoparticle Characterization……………………………….……..9.6. Cell culture……………………...……………..………….………11.7. In vitro cytotoxicity in dark…..………………………….………..11.8. Cellular uptake…………………………………………..………..12.9. Confocal laser scanning microscopy……………………….……..13.10. Photodynamic therapy efficiency of m-THPC loaded nanoparticles…………………………………………….……....13. Results……………………….………………………………….……..14.1. Synthesis and characterize of PEGMA-co-DPA…………………14.2. Nanoparticle characterization…………………………………….14.3. In vitro cytotoxicity of nanoparticles…………………………….18.4. Cellular uptake………………………………………..….………18.5. Photodynamic therapy efficiency………………………..……….19. Discussion……...…………………………………….………………..20. Conclusion……………………………………………………….…….24考文獻……………………………………………….……….……….. 25錄………………………………………….…………………………... 3
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
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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
- …
