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181.
Gordillo A de Jesús E López-Mardomingo C 《Chemical communications (Cambridge, England)》2007,(39):4056-4058
Symmetric and asymmetric (E)-1,2-diarylethenes are synthesized from aryl bromides by consecutive one-pot Hiyama-Heck reactions carried out in water and under air; the only additives required are sodium hydroxide, palladium acetate and poly(ethylene glycol), and the products are isolable in many cases by simple filtration of the water solution. 相似文献
182.
Alvarez-Aguilar C Enríquez-Ramírez ML Figueroa-Nuñez B Gómez-García A Rodríguez-Ayala E Morán-Moguel C Farías-Rodríguez VM Mino-León D López-Meza JE 《Experimental & molecular medicine》2007,39(3):327-334
Metabolic Syndrome (MS) is recognized as a cluster of cardiovascular risk factors. All components of MS have a genetic base. Genes of the renin angiotensin system are potential candidate genes for MS. We investigated whether angiotensin converting enzyme (ACE) gene polymorphism increases susceptibility to MS as an entity in a Mexican population. In a cross-sectional study, 514 individuals were studied including 245 patients with MS and 269 subjects without MS criteria. ACE gene polymorphism was detected using PCR. MS was defined according to The National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) criteria, except that the raised fasting plasma glucose 相似文献
183.
Bermejo JF Ortega P Chonco L Eritja R Samaniego R Müllner M de Jesus E de la Mata FJ Flores JC Gomez R Muñoz-Fernandez A 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(2):483-495
Novel amine- or ammonium-terminated carbosilane dendrimers of type nG-[Si{OCH2(C6H3)-3,5-(OCH2CH2NMe2)2}]x, nG-[Si{O(CH2)2N(Me)(CH2)2NMe2}]x and nG-[Si{(CH2)3NH2}]x or nG-[Si{OCH2(C6H3)-3,5-(OCH2CH2NMe3 +I-)2}]x, nG-[Si{O(CH2)2N(Me)(CH2)2NMe3 +I-}]x, and nG-[Si{(CH2)3NH3 +Cl-}]x have been synthesized and characterized up to the third generation by two strategies: 1) alcoholysis of Si--Cl bonds with amino alcohols and subsequent quaternization with MeI, and 2) hydrosilylation of allylamine with Si--H bonds of the dendritic systems and subsequent quaternization with HCl. Quaternized carbosilane dendrimers are soluble in water, although degradation is apparent due to hydrolysis of Si--O bonds. However, dendrimers containing Si--C bonds are water-stable. The biocompatibility of the second-generation dendrimers in primary cell cultures of peripheral blood mononuclear cells (PBMCs) and erythrocytes have been analyzed, and they show good toxicity profiles over extended periods. In addition, we describe a study on the interactions between the different carbosilane dendrimers and DNA oligodeoxynucleotides (ODNs) and plasmids along with a comparative analysis of their toxicity. They can form complexes with DNA ODNs and plasmids at biocompatible doses via electrostatic interaction. Also a preliminary transfection assay has been accomplished. These results demonstrate that the new ammonium-terminated carbosilane dendrimers are good base molecules to be considered for biomedical applications. 相似文献
184.
Back DF de Oliveira GN Burrow RA Castellano EE Abram U Lang ES 《Inorganic chemistry》2007,46(7):2356-2358
The reaction of Hg(TePh)2 with AgX (X = Cl, NO3) in the presence of PPh3 and PMePh2 in dimethylformamide (DMF) affords the cluster [Hg6Ag4(TePh)16] (1) at room temperature or [Hg6Ag4Te(TePh)14]2 (2) with heating. When Hg(TePh)2 is reacted with [Co(PPh3)2Cl2] or [Ni(PPh3)2Cl2], the clusters [Hg8Te(PhTe)12Cl4]Q [3; Q = [Co(DMF)6]2+ (3a), [Ni(DMF)6]2+ (3b)] are formed. The syntheses of 1 and 2 occur with the incorporation of AgI into the cluster, and the single-crystal analyses show that the two ternary clusters consist of Hg, Ag, and Te centers occupying well-defined positions. Compounds 3a and 3b do not show the incorporation of the metal into the cluster, but the CoII and NiII salts provide the Cl atom to generate the anionic cluster 3 stabilized by the [Co(DMF)6]2+ or [Ni(DMF)6]2+ ion. 相似文献
185.
M. Micó A. Labrada S. Calderón 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(2):471-474
X-ray analysis can be used to determine the quality of seeds, showing the cause of bad germination. X-ray images provide information
on the internal structure and morphology of seeds, mechanical damage, percentage of empty and filled seeds, microfractures,
possible embryo deformations and insect infestation. These techniques has been developed in Cuba for different X-ray sets.
In this article we describe the suitable working conditions for 32 agricultural and forestry species. We also explained the
main damages to seeds and their consequences for germination. If affected by insects, it could reduce the storage ability
of grains. 相似文献
186.
Rosario Benavente Ernesto Prez Raúl Quijada 《Journal of Polymer Science.Polymer Physics》2001,39(3):277-285
Stress–strain and microhardness measurements were carried out on a series of copolymers of ethylene and 1‐octadecene with different comonomer contents in the corresponding homopolymer of ethylene, synthesized with a metallocene catalyst. The different mechanical properties, deduced from the stress–strain curves (Young's modulus, yield stress, deformation at break, and energy to break) are interpreted in terms of the crystallinity and molecular weight of the samples because these two characteristics show considerable variations with the comonomer content. The microhardness values are explained in terms of these properties, and they are also correlated with Young's moduli and yield stresses deduced from the stress–strain curves. Linear relations are found between microhardness and yield stress and between the logarithm of the microhardness and the logarithm of the elastic modulus. The properties deduced from these lines are compared with literature values. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 277–285, 2001 相似文献
187.
Christian Slugovc Kurt Mereiter Swiatoslaw Trofimenko Ernesto Carmona 《Helvetica chimica acta》2001,84(10):2868-2883
A series of pyrazole‐substituted [hydrotris(1H‐pyrazolato‐κN1)borato(1−)]iridium complexes of the general composition [Ir(Tpx)(olefin)2] (Tpx=TpPh and TpTh) and their capability to activate C−H bonds is presented. As a test reaction, the double C−H activation of cyclic‐ether substrates leading to the corresponding Fischer carbene complexes was chosen. Under the reaction conditions employed, the parent compound [Ir(TpPh)(ethene)2] was not isolable; instead, (OC‐6‐25)‐[Ir(TpPhκCPh,κ3N,N′,N″)(ethyl)(η2‐ethene)] ( 1 ) was formed diastereoselectively. Upon further heating, 1 could be converted exclusively to (OC‐6‐24)‐[Ir(TpPhκ2CPh,CPh,κ3N,N′,N″)(η2‐ethene)] ( 2 ). Complex 1 , but not 2 , reacted with THF to give (OC‐6‐35)‐[Ir(TpPhκ3N,N′,N″)H(dihydrofuran‐2(3H)‐ylidene)] ( 3 ), a cyclic Fischer carbene formed by double C−H activation of THF. Accordingly, complexes of the general formula [Ir(Tpx)(butadiene)] (see 4 – 6 ; butadiene=buta‐1,3‐diene, 2‐methylbuta‐1,3‐diene (isoprene), 2,3‐dimethylbuta‐1,3‐diene) reacted with THF to yield 3 or the related derivative 9 . The reaction rate was strongly dependent on the steric demand of the butadiene ligand and the nature of the substituent at the 3‐position of the pyrazole rings. 相似文献
188.
189.
Chantal Galaup Joëlle Azma Pierre Tisns Claude Picard Patricia Ramos Olga Juanes Ernesto Brunet JuanCarlos Rodríguez‐Ubis 《Helvetica chimica acta》2002,85(6):1613-1625
Two macrobicyclic ligands derived from an 18‐membered tetralactam ring and 2,2′‐bipyridine or 2,6‐bis(pyrazol‐1‐yl)pyridine moieties, 1 and 2 , respectively, form stable complexes with GdIII, EuIII, and TbIII ions in aqueous solution. The ligand‐based luminescence is retained in the GdIII cryptates, whereas this radiative deactivation is quenched in the EuIII and TbIII cryptates by ligand‐to‐metal energy transfer, resulting in the usual metal‐centered emission spectra. Singlet‐ and triplet‐state energies, emission‐decay lifetimes, and luminescence yields were measured. [Tb⊂ 1 ]3+ cryptate shows a long luminescence lifetime (τ=1.12 ms) and a very high metal luminescence quantum yield (Φ=0.25) in comparison with those reported in the literature for Tb3+ complexes sensitized by a bipyridine chromophore. By comparison to [Ln⊂ 1 ]3+, [Ln⊂ 2 ]3+ presents markedly lower luminescence properties, due to worse interaction between the 2,6‐bis(pyrazol‐1‐yl)pyridine unit and the metal ion. Moreover, the luminescent metal and the triplet ligand energy levels of [Eu⊂ 2 ]3+ do not match. The effects of H2O molecules coordinated to the metal centre and of thermally activated decay processes on nonradiative deactivation to the ground‐state are also reported. 相似文献
190.
Ernesto Schulz Lang Robert Alan Burrow Lenice de Loureno Marques 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(3):m95-m96
The title compound, [Au(C10H9N4O2S)(C18H15P)], is nearly linear at AuI, with Au—N = 2.0707 (18) Å, Au—P = 2.2310 (8) Å and N—Au—P 171.93 (5)°. The molecules are linked by intermolecular N—H⃛O bonds. 相似文献