1,720,977 research outputs found
A Self-Immolative Linker for the pH-Responsive Release of Amides
Get PDFThe administration of therapeutics using bioconjugation has been mainly limited to drugs containing amine, alcohol, or thiol functional groups. Here, we report a general procedure for the preparation of benzylic N-acyl carbamates suitable for masking the amide group in important drugs such as Linezolid, Enzalutamide, or Tasimelteon in good to acceptable yields. These N-acyl carbamates appear to be stable in plasma, while a qualitative analysis of further drug uncage demonstrates that, at pH values of 5.5, a classical 1,6-benzyl elimination mechanism takes place, releasing more than 80% of the drug in 24 h
Bioactivity of Curcuminoids in Half-Sandwich Ru(II), Rh(III) and Ir(III) Complexes: benefits from cooking to medicine
No full textCurcumin has been used for centuries in Asia as a spice, natural colouring and traditional medicine owing to its anti-inflammatory, antioxidant and antitumoral effects [1]. An alternative strategy to improve the properties of curcumin, without the need to modify the drug, is its incorporation into metal complexes [2]. Ruthenium compounds have emerged in recent years as promising alternatives to
platinum drugs by displaying specific activities against different cancers, favorable toxicity and clearance properties [3]. Recently, also metal complexes based on Rhodium and Iridium have arisen as fascinating potential alternative metallodrugs [4]. In the present work we exploit the coordination chemistry of Ru(II) arene and pentamethylcyclopentadienyl Rh(III) and Ir(III) complexes with curcumin [5] and bisdemethoxycurcumin as co-ligands and full characterization of relative RAPTA type complexes with 1,3,5-triaza-7-phosphaadamantane ligand (PTA) [6]. Hydrolysis studies were carried out under pseudopharmacological conditions to evaluate their aqueous chemistry. The antiproliferative effects in two human ovarian cancer cell lines (A2780 and A2780cisR) and non-tumorigenic human embryonic kidney cells (HEK293) will be reported
Synthesis and Characterization of New Ruthenium(II) Arene Acylpyrazolone Complexes
No full textArene ruthenium(II) complexes have been widely studied in the recent years, and their chemistry has been extensively studied for arenes such as benzene and para-cymene. They have found applications in catalysis, supramolecular assemblies, molecular devices.1 Moreover, they have shown antiviral, antibiotic and anticancer activities.2 Recently, mononuclear Ru-acylpyrazolone complexes have been shown to exhibit interesting in vitro activity in some cancer cells.3 On the basis of the our previous work,4 we extend our investigation to the interaction of several acylpyrazolones ligands with (arene)ruthenium(II)dichloride acceptors and PTA (1,3,5-triaza-7-phosphaadamantane)(Figure 1). Their structures have been confirmed by analytical and spectral data. X-ray diffraction studies and their biological activity are under investigation
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
Selective Anticancer Ruthenium(II) Arene RAPTA Type Complexes Containing Curcuminoids
No full textRuthenium-arene complxes are considered valid alternatives to platinum drugs, owing to their lower toxicity and stronger selectivity. Since curcumin possesses anti-inflamatory, antioxidant and antitumoral effects, it has been extensively studied as a chemo preventive agent in some cancer models. As continuation of our previous work, a series of novel Ru(II) arene RAPTA type derivatives (areme = cymene and hexamethylbenzene) containing corcumin-based ligands (curcH = curcumin, bdcurcH = bisdemethoxycurcumin) and PTA (1,3,5-triaza-7-phosphaadamantane) has been synthesized and fully characterized. The antitumor activity of the complexes has been evaluated in vitroagainst human ovarian carcinoma cells, A2780 and A2780cisR, as well as against non-tumorous Human Embryonic Kidney (HEK293) cells
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
Comparison of Methods for Lipid Extraction from clam Scapharca inaequivalvis
No full textClam Scapharca inaequivalvis is a bivalve mollusk of Indo-Pacific origin, currently living also in the Adriatic Sea. Despite its content of valuable nutrients,1 it is not much appreciated as food in Mediterranean area and thus fishermen must pick it out from the clam Camelea gallina.2 Some of its precious nutrients are polyunsaturated fatty acids (PUFA) having a well-known beneficial influence on the vascular system. Considering this mollusk as a possible source of PUFA, our study was aimed at evaluating the efficiency of several methods with respect to the extraction of total lipids and the individual classes of fatty acids (saturated, monounsaturated and polyunsaturated). Conventional methods as Folch, Bligh and Dyer, and Soxhlet extraction with different solvents were tested, but also accelerated solvent extraction (ASE) and the use of low toxicity-solvents were evaluated. The highest yield of total lipid extract was 7.0 % (duplicate averaged, in relation to dry sample), obtained using ASE with chloroform/methanol, followed by a washing step with water. The next-highest yield (6.1 %) was afforded by Folch method, while the lowest yields were afforded by extraction with hexane/2-propanol and by Soxhlet extraction with hexane (2.3 %). The estimated percent total fatty acids in the total lipid extract ranged from 19.6 % (Folch method) to 39.4 % (Soxhlet extraction with hexane). The estimated percent PUFA in the total fatty acids ranged from 10.8 % (Soxhlet with hexane) to 22.5 % (ASE with chloroform/methanol).
References
1) Piretti, M.V.; Taioli, F.; Pagliuca, G. Comparative Biochemistry and Physiology 1987, 88B, 1201-1208.
2) Pierantozzi, C.; Zambuchini, B.; Giosia, L.; Faini, V.; D‘Angelo, N.; Spina, M.; Ventura, A.; Buttafoco, S.; Sturba, M.; Quagliarini, C. Progress in Nutrition 2005, 7, 1-9
Synthesis, Structures and Antiproliferative Activity of Novel Ru(II)-Arene Complexes with N,O-Chelating β-Ketoamine Ligands
No full textOrganometallic compounds are attracting a considerable interest in medicinal chemistry, especially as putative anticancer compounds. Of particular interest are ruthenium-arene complexes which have been extensively studied and modified to obtain compounds with various therapeutic effects. Ruthenium arene complexes with β-ketoamine ligands derived from 4-acyl-5-pyrazolones possess relevant anticancer properties in vitro. It was found that minor changes to the β-ketoamine ligand lead to considerable changes in cytotoxicity and, consequently, a series of novel Ru(II)-arene derivatives containing β-ketoamine ligands L' (HL' in general, HLbiph,ph, HLbiph,naph, HLph,naph, HLhex,naph) has been synthetized and fully characterized by spectroscopy and single-crystal X-ray diffraction. The ligands in the anionic form coordinate to the ruthenium ion in a chelating κ2 N,O-bidentate mode, affording 1:1 derivatives of the formula [(arene)Ru(L')Cl]. The in vitro anticancer activity of both the ligands and complexes has been evaluated against the human ovarian carcinoma cell line A2780 and its cisplatin-resistant equivalent A2780R
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