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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
Excited State Dynamics and Charge Transfer States of Functional Molecules Probed by Electric Field Modulation Spectroscopy
No full text本論文では、重要な機能性分子であるチオフラビンT ThT ）、および 7,7,8,8 テトラシアノキノジメタン ( に着目し、励起状態ダイナミクス、および電荷移動（ CT ）状態を研究するために電場変調分光法を用いた。アミロイドβタンパク質のアミロイド線維（A β）は、神経変性疾患に関連する毒性のある物質と考えられている。 ThT は、 A βを検出するための蛍光マーカーとして広く利用されている分子である。 ThT が A βに結合すると、蛍光性の局所励起（ LE ）状態から非蛍光性のねじれ型分子内 CT 状態への変化をともなう内部回転（ IMR ）が抑制され、そのため蛍光強度が大きく増加す ると考えられている。しかし A βに 混合 すると IMR が抑制されるにもかかわらず、 ThT の蛍光量子収率は 1 よりもかなり小さいことが知られている。このような予想と実験事実のあいだの不一致の理由を説明するために、本研究では、 A β表面に存在する電場が ThT に作用する可能性に着目し、 ThT の励起状態に対する電場効果を解明することを目的とした。実験として電場吸収（ EA ）分光法およびシュタルク蛍光 SF ）分光法を用い、 PMMA 高分子中に分散させた ThT に電場を加えることにより、 A β表面に存在する電場を模倣した。 EA スペクトル の解析により、 ThT の励起状態には LE 状態と CT 状態に帰属できる 2 つの電子状態が存在することを明らかにした。 SF スペクトルの測定により、電場が存在すると LE 状態と CT 状態の状態間 混合 が増大し、蛍光量子収率は減少することがわかった。また単位電場強度あたりの蛍光消光効率を求め、 ThT の蛍光量子収率の実測値を用いることで、 A βの表面には最大で 9 MV cm 1 に達する強い電場が存在する可能性を明らかにした。TCNQは材料化学および有機エレクトロニクスなど様々な分野で利用される重要な分子である。しかし その重要性にもかかわらず、その励起状態は、ごく最近になるまで全く研究がすすんでいなかった。本研究では EA スペクトルを測定し、その解析から、 LE状態と分子内CT状態に帰属できる2つの電子状態が存在することを明らかにした。さらに２つの電子状態のあいだに状態間混合が生じていることを明らかにした。以上、本論文では、電場変調分光法を用いることにより、機能性分子のCT状態を測定し、励起状態ダイナミクスを理解する鍵となる状態間混合について研究した。本研究で得られた新たな知見は、これらの機能性分子を諸分野に応用するうえで有用であると考えられる。This thesis employs electric field modulation spectroscopies to investigate the excited state dynamics and charge transfer states of functional molecules, thioflavin T (ThT) and 7,7,8,8 tetracyanoquinodimethane (TCNQ).
Thioflavin T (ThT) is a widely used fluorescent marker for detecting amyloid-β (Aβ) fibrils, which are toxic protein aggregates associated with neurodegenerative diseases. When ThT binds to Aβ, it undergoes a significant increase in fluorescent intensity because of the inhibition of the intramolecular rotation (IMR) which accompanies the transition from an emissive locally excited (LE) state to a nonemissive twisted intramolecular charge transfer (CT) state, making it a "gold-standard" marker for Aβ. However, despite the inhibition of IMR, the quantum yield of ThT on Aβ fibrils is much smaller than unity. To explain this discrepancy, we considered the electric fields which might be experienced by ThT on the Aβ protein surface in this study. We studied the photophysics of ThT dispersed in a rigid polymethylmethacrylate (PMMA) matrix in the presence of an external electric field utilizing electroabsorption (EA) and Stark fluorescence (SF) spectroscopies, which mimics the Aβ fibrils surface environment. The study revealed the presence of the LE and CT states in the excited state of ThT. Furthermore, the SF analysis revealed that the coupling between these states was enhanced in the presence of an external electric field, leading to the observed fluorescence quenching in the SF spectra. By calculating the fluorescence quenching efficiency from the SF spectra, the electric field strength of the Aβ fibrils' surface was estimated to be approximately 9 MV cm-1.
TCNQ and its analogs are important electron acceptors in materials chemistry and organic electronics. TCNQ is considered as a model system for this class of molecules. A limited number of studies were reported on the fluorescence spectra more than 30 years ago, but the excited state was not comprehensively studied until recently. The EA spectrum observed in this study provided concrete experimental evidence of the existence of multiple electronic states in the excited state of TCNQ, which were assigned to the LE and intramolecular CT states. Furthermore, we were able to demonstrate the state mixing between the two states.
The findings of this thesis highlight the efficacy of electric field modulation spectroscopies in probing the CT state and understanding the state mixing among the excited states of functional molecules. The insights gained in this study are critical for enhancing the utilization of these molecules in their respective fields
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
電場変調分光法を用いた機能性分子の励起状態ダイナミクスと電荷移動状態の研究
Get PDF室蘭工業大学Muroran Institute of Technology博士（工学）本論文では、重要な機能性分子であるチオフラビンT ThT ）、および 7,7,8,8 テトラシアノキノジメタン ( に着目し、励起状態ダイナミクス、および電荷移動（ CT ）状態を研究するために電場変調分光法を用いた。アミロイドβタンパク質のアミロイド線維（A β）は、神経変性疾患に関連する毒性のある物質と考えられている。 ThT は、 A βを検出するための蛍光マーカーとして広く利用されている分子である。 ThT が A βに結合すると、蛍光性の局所励起（ LE ）状態から非蛍光性のねじれ型分子内 CT 状態への変化をともなう内部回転（ IMR ）が抑制され、そのため蛍光強度が大きく増加す ると考えられている。しかし A βに 混合 すると IMR が抑制されるにもかかわらず、 ThT の蛍光量子収率は 1 よりもかなり小さいことが知られている。このような予想と実験事実のあいだの不一致の理由を説明するために、本研究では、 A β表面に存在する電場が ThT に作用する可能性に着目し、 ThT の励起状態に対する電場効果を解明することを目的とした。実験として電場吸収（ EA ）分光法およびシュタルク蛍光 SF ）分光法を用い、 PMMA 高分子中に分散させた ThT に電場を加えることにより、 A β表面に存在する電場を模倣した。 EA スペクトル の解析により、 ThT の励起状態には LE 状態と CT 状態に帰属できる 2 つの電子状態が存在することを明らかにした。 SF スペクトルの測定により、電場が存在すると LE 状態と CT 状態の状態間 混合 が増大し、蛍光量子収率は減少することがわかった。また単位電場強度あたりの蛍光消光効率を求め、 ThT の蛍光量子収率の実測値を用いることで、 A βの表面には最大で 9 MV cm 1 に達する強い電場が存在する可能性を明らかにした。TCNQは材料化学および有機エレクトロニクスなど様々な分野で利用される重要な分子である。しかし その重要性にもかかわらず、その励起状態は、ごく最近になるまで全く研究がすすんでいなかった。本研究では EA スペクトルを測定し、その解析から、 LE状態と分子内CT状態に帰属できる2つの電子状態が存在することを明らかにした。さらに２つの電子状態のあいだに状態間混合が生じていることを明らかにした。以上、本論文では、電場変調分光法を用いることにより、機能性分子のCT状態を測定し、励起状態ダイナミクスを理解する鍵となる状態間混合について研究した。本研究で得られた新たな知見は、これらの機能性分子を諸分野に応用するうえで有用であると考えられる。This thesis employs electric field modulation spectroscopies to investigate the excited state dynamics and charge transfer states of functional molecules, thioflavin T (ThT) and 7,7,8,8 tetracyanoquinodimethane (TCNQ).
Thioflavin T (ThT) is a widely used fluorescent marker for detecting amyloid-β (Aβ) fibrils, which are toxic protein aggregates associated with neurodegenerative diseases. When ThT binds to Aβ, it undergoes a significant increase in fluorescent intensity because of the inhibition of the intramolecular rotation (IMR) which accompanies the transition from an emissive locally excited (LE) state to a nonemissive twisted intramolecular charge transfer (CT) state, making it a "gold-standard" marker for Aβ. However, despite the inhibition of IMR, the quantum yield of ThT on Aβ fibrils is much smaller than unity. To explain this discrepancy, we considered the electric fields which might be experienced by ThT on the Aβ protein surface in this study. We studied the photophysics of ThT dispersed in a rigid polymethylmethacrylate (PMMA) matrix in the presence of an external electric field utilizing electroabsorption (EA) and Stark fluorescence (SF) spectroscopies, which mimics the Aβ fibrils surface environment. The study revealed the presence of the LE and CT states in the excited state of ThT. Furthermore, the SF analysis revealed that the coupling between these states was enhanced in the presence of an external electric field, leading to the observed fluorescence quenching in the SF spectra. By calculating the fluorescence quenching efficiency from the SF spectra, the electric field strength of the Aβ fibrils' surface was estimated to be approximately 9 MV cm-1.
TCNQ and its analogs are important electron acceptors in materials chemistry and organic electronics. TCNQ is considered as a model system for this class of molecules. A limited number of studies were reported on the fluorescence spectra more than 30 years ago, but the excited state was not comprehensively studied until recently. The EA spectrum observed in this study provided concrete experimental evidence of the existence of multiple electronic states in the excited state of TCNQ, which were assigned to the LE and intramolecular CT states. Furthermore, we were able to demonstrate the state mixing between the two states.
The findings of this thesis highlight the efficacy of electric field modulation spectroscopies in probing the CT state and understanding the state mixing among the excited states of functional molecules. The insights gained in this study are critical for enhancing the utilization of these molecules in their respective fields.doctoral thesi
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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