69 research outputs found
H-Content Is Not Predictive of Perfluorocarbon Ocular Endotamponade Cytotoxicity in Vitro
In recent years, cases of retinal toxicity occurred in some European, Middle Eastern, and South American countries following the use of perfluorocarbon liquids (PFCLs) on vitreoretinal surgeries owing to impurities in the product. Moreover, Spanish ophthalmologists reported several toxic cases on the use of perfluoro-n-octane Ala Octa (Alamedics, Dornstadt, Germany), raising the necessity of reviewing the current validated methods used for assessing the safety of PFCLs. We proved that in samples of PFCLs contaminated on purpose with impurities previously detected in Ala Octa devices, the determination of the so-called H-content using a 1H NMR quantitative assay implemented with the electronic reference to access in vivo concentrations 2 technology failed to demonstrate a correlation between the H-content and in vitro cytotoxicity test in ARPE-19 and BALB 3T3 cell lines. Therefore, direct information on the safety of PFCLs was provided only by the cytotoxicity test in vitro validated according to ISO 10993-5, and the H-content was not predictive of perfluorocarbon ocular endotamponade cytotoxicity in vitr
CMS physics technical design report : Addendum on high density QCD with heavy ions
Peer reviewe
Diagnosis, monitoring and prevention of exposure-related non-communicable diseases in the living and working environment: DiMoPEx-project is designed to determine the impacts of environmental exposure on human health
rac-2-[(2-Chlorophenyl)(4-chlorophenyl)methyl]-1,3-dioxolane
The title compound, C16H14Cl2O2, is a chiral mitotane derivative that contains a dioxolane ring and crystallizes from methanol as a racemic mixture. It was obtained in high yield from mitotane and ethyleneglycol in alkaline medium, followed by neutralization with sulfuric acid and extraction with ethyl acetate. The molecular structure is stabilized by an intramolecular C— H... O hydrogen bond. The dihedral angle between the aromatic rings is 80.1 (2)°. The dioxolane ring adopts a puckered envelope conformation with an O atom as the flap
Perylene side chains modulate G-quadruplex conformation in biologically relevant DNA sequences
he stabilisation of different G-quadruplex intra-and intermolecular structures by a number of perylene derivatives characterised by side chains ending with linear or cyclic amines was investigated by electrophoretic (EMSA) and spectroscopic (CD) techniques. The G-rich sequences included the biologically relevant human telomeric TTAGGG runs and the NHE region of the c-myc oncogene.
The test compounds could be subdivided into two families: derivatives carrying a cyclic amine in the side chains, which show a reduced binding to the G-quadruplex form, and linear amine congeners, exhibiting enhanced affinity. The latter efficiently induce pairing of multiple DNA chains, while the former are not able to overcome the original folding of the nucleic acid sequence which is preserved in the complex. Remarkably, addition of the perylenes to G-rich sequences paired in a double helical form results in G-quadruplex induction by weak binders only. This is likely related to the ability of strong G-quadruplex binders, but not of weak G-quadruplex binders, to efficiently intercalate into the doublestranded arrangement, which becomes stabilised and is not prone to undergo denaturation and subsequent G-quadruplex folding essentially for kinetic reasons. Hence, two apparently conflicting requirements emerge from this work. In fact, linear alkylamino terminals in the perylene side chains are capable of strong and selective G-quadruplex recognition, but only cyclic amine end groups favour duplex-quadruplex transitions that are likely crucial to produce biological and pharmacological effects in living systems
Supramolecular architectures and crystal structures of gold(III) compounds with semicarbazones
<p>The synthesis and crystal structures of two novel semicarbazones and four gold(III) compound derivatives of these semicarbazones are presented. A pattern in the formation of the semicarbazones shows the association of Cl<sup>–</sup> ions held together by intra- and intermolecular forces. [AuCl<sub>4</sub>]<sup>−</sup> and [AuBr<sub>4</sub>]<sup>−</sup> anions are co-crystallised with these semicarbazone ligands, and the packing architectures revealed by a single-crystal X-ray diffraction analysis showed the different influences of the anions and the association of these chemical species by intermolecular forces on the crystal packing. Crystal engineering led to gold(III) compounds that are stabilised by relevant hydrogen bonding networks, which demonstrated their importance to the supramolecular organisation of the studied compounds. Interestingly, Cl∙∙∙Br interactions are observed and contribute to the formation of the supramolecular structures. Elemental analysis data and spectroscopic properties in the solid state and solution are also described.</p> <p>Six new compounds were synthesised, including two semicarbazones and four gold(III) compound derivatives of these semicarbazones. The structural characterisation using single-crystal X-ray diffraction studies revealed cation–anion and Cl∙∙∙Br interactions and some H-bond contributions for the formation of supramolecular structures and crystal packing.</p
Syntheses, structural and spectral studies of six-coordinate, [Ph2SnCl(acpm)], and seven-coordinate, [(Bu2Sn)-Bu-n(dapm)], diorganotin(IV) complexes with N,N,S-tridentate and S,N,N,N,S-pentadentate N-4-heterocyclic thiosemicarbazones
The reaction of the N,N,S-tridentate ligand 2-acetylpyridine (N-4-morpholyl thiosernicarbazones), Hacpm, with Ph2SnCl2 leads to the formation of the six-coordinate complex [Ph2SnCl(acpm)] (1), whereas the reaction of the S,N,N,N,S-pentadentate ligand 2,6-diacetylpyridine bis(N-4-morpholyl thiosemicarbazone), H(2)dapm, with "BuSnCl2 leads to the formation of the seven-coordinate complex ["Bu2Sn(dapm)] (2). Both compounds were studied by microanalyses, IR, NMR (H-1, C-13, Sn-119) and Mossbauer spectroscopy to investigate their structural properties. The organotin(IV) complexes were also studied by single crystal X-ray diffraction and the structure determination revealed that the phenyl derivative crystallizes in the triclinic space group (P1) as discrete neutral molecules, with the tin(IV) ion in a distorted octahedral geometry with the acpm(1-) ligand in a meridional configuration and the phenyl groups in trans positions. X-ray analysis shows that the n-butyl complex crystallizes in the monoclinic space group (P2(1)/c) as discrete neutral complexes, with the tin(IV) ion in a distorted pentagonal bipyramidal geometry. A correlation between Mossbauer and X-ray data based on the point-charge model is discussed. (c) 2006 Elsevier B.V. All rights reserved
Synthesis, Spectroscopic Studies and X-ray Crystal Structures of New Pyrazoline and Pyrazole Derivatives
The synthesis and characterization of some pyrazoline compounds of 1,3-diketones with hydrazine derivatives, namely, 1-(S-benzyldithiocarbazate)-3-methyl-5-phenyl-5-hydroxypyrazoline (1); 1-(2-thiophenecarboxylic)-3-methyl-5-phenyl-5-hydroxypyrazoline (2); 1-(2-thiophenecarboxylic)-3,5-dimethyl-5-hydroxypyrazoline (3); 1-(S-benzyldithiocarbazato)-3-methyl-5-phenylpyrazole (4); 1-(2-thiophenecarboxylic)-3-methyl-5-phenylpyrazole (5) and 1-(S-benzyldithiocarbazate)-3,5-dimethylpyrazole (6) are reported. Studies by IR, ((1)H, (13)C)-NMR spectroscopies and single crystal X-ray diffraction revealed that compounds (1)(,) (2) and (3) are formed as pyrazoline, whereas (4) and (5) are formed as pyrazole derivatives only under acidic conditions. Compound (1) crystallizes in orthorhombic P2(1)2(1)2(1), a = 6.38960(10) angstrom, b = 12.9176(3) angstrom, c = 21.2552(5) angstrom, (2) crystallizes in monoclinic, P2(1)/n, a = 11.3617(2) angstrom, b = 8.4988(2) angstrom, c = 92.8900(10)angstrom and beta = 92.8900(5)degrees, (3) crystallizes in monoclinic, C2/c, a = 15.9500(5) angstrom, b = 9.3766(3) angstrom, c = 16.6910(5)angstrom and beta = 113.825(2)degrees, (4) crystallizes in monoclinic, P2(1)/c, a = 15.228(4) angstrom, b = 5.5714(13) angstrom, c = 19.956(5)angstrom and beta = 91.575(7)degrees and (6) crystallizes in orthorhombic, P2(1)2(1)2(1), a = 5.3920(2) angstrom, b = 11.2074(5) angstrom, c = 21.885(1)angstrom . The (3) derivative represents the first pyrazoline compound prepared from 2,4-pentanedione and characterized crystallographically.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPqFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESPFinanciadora de Estudos e Projetos (FINEP)FINEP[CT-INFRA 0970/01]Conselho Nacional de Desenvolvimento Cientifico e Tecnologico-CNPq[307412/2008-3]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
A Molecular Dynamics Simulation Study on the Self-Association Propensity of Aib HOMO-Peptides of different Main-Chain Length
- …