1,720,979 research outputs found
Identifying highly effective fludarabine-based novel target cancer therapy agents by in silico studies
Full text linkAim: To develop an alternative drug molecule design to fludarabine which is commonly used in chronic lymphocytic leukemia.
Methods: The molecular properties and biological activities of the drug molecules were determined using Molinspiration software. We investigated the biological activity and drug properties of fludarabine by changing the positions of bioisosteres on the molecular structure.
Results: In our studies of derivatives of the fludarabine drug molecule, we obtained data by adding different structures to the Y part without changing the X structure (F) of fludarabine. We have used the abbreviation 'M' to refer to the molecules in these experiments. We predict that the M6 derivative of fludarabine will have higher ion channel modulator, kinase and protease activity compared to fludarabine. We predict that the M15 derivative of fludarabine will have higher G- protein coupled receptors, ion channel modulator, kinase, and protease and enzyme inhibition activity compared to fludarabine. In our experiments with fludarabine derivatives, we have experimented by binding different molecules to both the X and Y structures of fludarabine at the same time. We have used the abbreviation 'C' to refer to the molecules in these experiments. In these experiments, we did not achieve higher biological activity than fludarabine.
Conclusions: The results suggest that this newly designed M15 derivative of fludarabine molecule may be a better antileukemic drug molecules in the future and may be useful for further drug molecule development research in medical biochemistry, chemistry and pharmacology
Synthesis and characterization of a new poly(dithieno ( 3,2-b: 2 ', 3 '-d) pyrrole) derivative conjugated polymer: Its electrochromic and biosensing applications
Full text linkWOS:000418581800006Synthesis and electropolymerization of a new conjugated dithieno(3,2-b: 2',3'-d) pyrole (DTP) derivative, namely, 2-(2-(2-(4H-dithieno[3,2-b: 2',3'-d] pyrrol-4-yl) ethoxy) ethoxy) ethanamine, (DTP-alkoxy-NH2) monomer are presented. The electrochemical, spectroelectrochemical effects and biosensor capability towards to glucose oxidase enzyme of P(DTP-alkoxy-NH2) polymer film are investigated in detail during the placement of alkoxy-NH2 functional unit in the polymer. Electrochemical and optical results between neutral and oxidized states of the polymer film show that (P(DTP-alkoxy-NH2)) has reversibly multi-electrochromic behaviors. Furthermore, glucose oxidase enzyme (GOx) is covalently immobilized on Au electrodes modified with P(DTP-alkoxy-NH2) conducting polymer. This enzyme is entrapped into conducting polymer during electropolymerization of DTP monomer on the electrodes. Some characterization parameters (Maximum reaction rate, Michaelis-Menten constants, temperature, pH and operational stabilities) for this kind of biosensor application is also determined. (C) 2017 Elsevier Ltd. All rights reserved.Karamanoglu Mehmetbey UniversityKaramanoglu Mehmetbey University [06-M-15]The author gratefully acknowledges the financial support from Karamanoglu Mehmetbey University (Grant No: 06-M-15)
Synthesis of new types of conductive polymer structures and development of nanofiber based biocompatible sensor systems
No full textYÖK Tez No: 716547İletken polimerler, geniş bir kullanım alanına sahip olması bakımından bilim dünyasında kendisine çok önemli bir yer edinmiştir. Birçok farklı kullanım alanının yanında son yıllarda biyosensör uygulamalarında da, üretilen biyosensörlerde kararlılığının artması, cevap verme süresinin kısa olması ve duyarlılığın artması gibi avantajları sebebiyle iletken polimerlerin kullanımı oldukça popüler hale gelmiştir. Bu tez projesi kapsamında yeni tipte iletken polimer yapıların sentezi yapılmış ve nanolif tabanlı biyouyumlu sensör sistemleri geliştirilmiştir. DTP bileşiğinde bulunan N-H bağı, benzil amin grupları gibi farklı elektron salıcı ve elektron çekici gruplar ile fonksiyonelleştirilmiştir. Böylece değişen elektron yoğunluğuna bağlı olarak elektriksel iletim mekanizmasında yaşanan değişim kıyaslanmış ve literatürde daha önce bulunmayan ve sentezlenmemiş yeni nesil DTP bileşiklerinin sentezi ve biyonanoteknolojik alana yönelik uygulamaları gerçekleştirilmiştir. H2O2 tayini için Polivinilalkol/Poly(DTP- NH2) nanofiberleri üzerine alkol oksidaz enzimleri elektrokimyasal yöntemlerle bağlanarak Polivinilalkol/Poly(DTP- NH2)/Alkol Oksidaz biyosensörü hazırlandı. H2O2 sağlık, gıda, temizlik gibi günlük hayatta birçok alanda kullanılması açısından önemli bir maddedir. Bu nedenle biyosensörler kullanılarak H2O2 tayini yapılması hızlı, güvenilir, doğru, pratik ve ucuz bir yöntemdir. Sentezlenen polimerler iletken polimerlerin doğası ve nano liflerdeki yüzey/alan oranının yüksek olması ile biyosensörün elektrokimyasal duyarlılığı artmıştır. Bu sayede sensör cevabı hızlanmış ve hedef analit ile hazırlanan biyoelektronik yüzey üzerindeki etkileşimin farklılık göstermesine sebep olmuştur.Conductive polymers have gained a very important place in the scientific world in terms of having a wide range of uses. In addition to many different usage areas, the use of conductive polymers has become very popular in biosensor applications in recent years due to advantages such as increased stability, shorter response time and increased sensitivity in biosensors produced. Within the scope of this thesis project, new types of conductive polymer structures were synthesized and nanofiber-based biocompatible sensor systems were developed. The N-H bond in the DTP compound is functionalized with different electron donating and electron withdrawing groups such as benzyl amine groups. Thus, by comparing the change in the electrical conduction mechanism depending on the changing electron density, the synthesis and bionanotechnological applications of new generation DTP compounds, which were not previously found in the literature and were not synthesized, were carried out. For the determination of H2O2, a Polyvinylalcohol/Poly(DTP- NH2)/Alcohol Oxidase biosensor was prepared by electrochemical coupling of alcohol oxidase enzymes on Polyvinyl alcohol/Poly(DTP- NH2) nanofibers. H2O2 is an important substance in terms of its use in many areas of daily life such as health, food and cleaning. Using biosensors for this H2O2 determination is a fast, reliable, accurate, practical and inexpensive method. The electrochemical sensitivity of the biosensor increased with the nature of synthesized polymers, conductive polymers and the high surface/area ratio in nanofibers. In this way, the sensor response was accelerated and the interaction on the prepared bioelectronic surface changed
Ditiyonepirol(DTP) tarzı iletken polimerlerin sentezi, karakterizasyonu ve bu polimerlerin biyosensör uygulamaları
Full text linkTEZ 537.62/AZAdDoktora tezidir. Kaynakça: 145-159 ss.[Özet Yok
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
Electrochemical glucose biosensing via new generation DTP type conducting polymers/gold nanoparticles/glucose oxidase modified electrodes
No full textThe synthesis of derivatives of dithionepyrrole is a hot subject that has been studied extensively. In this study, a novel approach for constructing different glucose biosensors using conducting polymers of 4-(4H-dithyinol[3,2-b:2′,3′-d]pyroll-4-yl)aniline and 4-(4H-dithyinol[3,2-b:2′,3′-d]pyroll-4-yl)-[1,1′-biphenyl]-4-amine is proposed. After the synthesis and characterizations of the dithionepyrrole type monomers, they were used in glucose biosensing applications. The surface of gold electrode was modified with mercaptoethane sulfonic acid and p-aminothiophenol functionalized gold nanoparticles and aniline modified GOx. Electrochemical measurements were carried out by following the consumed oxygen due to the enzymatic reaction of glucose oxidase. DTP-Ph-NH2/AuNP/GOx and DTP-Ph-Ph-NH2/AuNP/GOx biosensors showed very good linearity between 0.1 and 2.5 mM, and 0.05 and 1 mM for glucose, respectively. LOD value was obtained for pDTP-Ph-NH2/AuNP/GOx as 5.00 × 10− 2 mM and for pDTP-Ph-Ph-NH2/AuNP/GOx as 9.86 × 10− 5 mM using S/N ratio. Optimization of molar ratio amount of AuNP/GOx, cycles amount to immobilize AuNP/GOx, conducting polymer thickness were examined. Finally, under optimized conditions, the amount of glucose in spiked human serum samples and recovery experiments were conducted. © 2016 Elsevier B.V
A novel immobilization matrix for the biosensing of phenol: Self assembled monolayers of calixarenes [Phenolün biyosensörle belirlenmesi için yeni bir immobilizasyon matriksi: Kaliksarenlerin kendiliğinden oluşan tek tabakaları]
Full text linkAim: The development of calixarene based phenol biosensor. Methods: This study describes the application of a calixarene derivative, 5,17-diamino-25,27-bis(3-thiol-1-oxypropane)-26,28-dihydroxycalix[4]arene (HS-Calix-NH2) which has both amino and thiol functionalities, in the practical surface modifications for biomolecule binding. The structure of HS-Calix-NH2 allows easy interaction with Au surface and one-step biomolecule immobilization. Self-assembled monolayers (SAMs) of p-aminofunctionalized mercaptoalkylcalixarene (HS-Calix-NH2) were formed onto the Au electrode. Then, Laccase (Lac) enzyme was immobilized onto the modified surface by crosslinking with glutaraldehyde (GA). Resulted electrode (HS-Calix-NH2/Lac) was used for the electrochemical analysis of phenolic compounds at - 50 mV. Results: The linearity was observed in the range of 0.1-100 µM and 1.0-100 µM for catechol and phenol, respectively. The potential use of the biosensor was investigated for phenol analysis in artificial samples which simulate the industrial waste water, which is highly acidic and composed of concentrated salt, without needing any sample pre-treatment step. Conclusion: The prepared Lac biosensor has a potential for rapid, selective and easy detection of phenolic contaminations in samples. © 2017 Turkish Biochemistry Society. All rights reserved
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
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