Search results for "Bromide"
showing 10 items of 591 documents
On the Shape-Selected, Ligand-Free Preparation of Hybrid Perovskite (CH3NH3PbBr3) Microcrystals and Their Suitability as Model-System for Single-Crys…
2021
Hybrid perovskite materials are one of the most promising candidates for optoelectronic applications, e.g., solar cells and LEDs, which can be produced at low cost compared to established materials. Although this field of research has seen a huge upsurge in the past decade, there is a major lack in understanding the underlying processes, such as shape-property relationships and the role of defects. Our aerosol-assisted synthesis pathway offers the possibility to obtain methylammonium lead bromide (MAPbBr3 ) microcrystals from a liquid single source precursor. The differently shaped particles are aligned on several substrates, without using a directing agent or other additives. The obtained …
Colorimetric susceptibility testing for Aspergillus fumigatus: comparison of menadione-augmented 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazo…
1996
Two colorimetric methods that use Alamar Blue or 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) for assaying the in vitro activities of antifungal agents have been described. We report that both tests performed similarly when the antifungal activity of amphotericin B against Candida albicans was determined. However, only the MTT test generated interpretable data when Aspergillus fumigatus was used.
Ethidium bromide: a fast fluorescent staining procedure for the detection of symbiotic partnership of flagellates and prokaryotes
1999
The hindgut of 'lower' termites harbors a dense population of flagellates and bacteria. The flagellates possess ecto- and endosymbiotic prokaryotes. Most of them are hardly visible in the phase contrast microscope. Staining with the DNA-intercalating agent ethidium bromide visualizes the nuclei of the flagellates as well as the ecto- and endosymbiotic bacteria as red objects. Furthermore, it is possible to distinguish between endosymbiotic methanogens and other bacteria. Following UV excitation, the blue-green autofluorescence of the methanogenic bacteria eclipses the red fluorescence light of the intercalated ethidium bromide. The dye facilitates the observation of symbiotic bacteria and h…
Kinetic study of ionic liquid synthesis in a microchannel reactor
2010
Abstract A microchannel reaction system, mainly consisting of a micromixer and a tubular reactor, was used to investigate the kinetics of butylation of 1-methyl-imidazole [MIM] for the synthesis of the ionic liquid 1-butyl-3-methylimidazolium bromide ([BMIM]Br). The low variance (σθ2 = 0.019) of the residence time distribution, measured by a step stimuli–response tracer method, implies that this reaction system could be regarded as a plug flow reactor. As a fast and reliable method, the titration of bromide was established to determine the yield of [BMIM]Br. The reaction kinetics was studied by varying the molar ratio of 1-bromobutane [BrBu] to [MIM] (1.04–1.49) and temperature (75–90 °C). …
EMPLOYMENT OF CATIONIC SOLID-LIPID NANOPARTICLES AS RNA CARRIERS
2007
Gene transfer represents an important advance in the treatment of both genetic and acquired diseases. In this article, the suitability of cationically modified solid-lipid nanoparticles (SLN) as a nonviral vector for gene delivery was investigated, in order to obtain stable materials able to condense RNA. Cationic SLN were produced by microemulsion using Compritol ATO 888 as matrix lipid, Pluronic F68 as tenside, and dimethyldioctadecylammonium bromide (DDAB) as cationic lipid. The resulting particles were approximately 100 nm in size and showed a highly positive surface charge (+41 mV) in water. Size and shape were further characterized by scanning electron microscopy (SEM) measurements. M…
Cyclic triureas—synthesis, crystal structures and properties
2008
The synthesis of 24-membered macrocycles is described, in which rigid xanthene units (X) and/or diphenyl ether units (D) as flexible analogues are linked via urea groups. All four possible combinations (XXX, XXD, XDD, DDD) have been obtained with yields of 40-72% for the cyclisation step. In two cases, the respective cyclic hexamers (XXDXXD, XXXXXX) were also isolated. Two compounds have been characterised by a single crystal X-ray analysis of the free triurea (XXD, XDD) and one example (DDD) by its complex with tetrabutylammonium chloride. It shows the chloride anion in the centre of the macrocycle, held by six NH...Cl- hydrogen bonds. The interaction with various other anions has been stu…
Dramatic selectivity differences in the association of DNA and RNA models with new ethylene- and propylene diamine derivatives and their copper compl…
2006
The affinities of polyamines consisting of ethylenediamine units equipped with either one or two terminal naphthyl-, anthryl-, or acridyl units towards PolyA.PolyU as an RNA model, and Poly(dA).Poly(dT) as a DNA model are screened by measuring the melting point changes (DeltaT(m)) of the double strands, and also partially by a fluorimetric binding assay using ethidium bromide. The larger aromatic moieties with long spacers between them allow bisintercalation; this leads to an increased preference for DNA in comparison to RNA, where ion pairing of the ammonium centers with the major RNA groove phosphates dominates. Allosteric affinity control by metalation is achieved e.g. with Cu(2+) ions, …
Synthesis, photophysical properties and structures of organotin-Schiff bases utilizing aromatic amino acid from the chiral pool and evaluation of the…
2017
Abstract Five new organotin(IV) complexes of compositions [Me 2 SnL 1 ] ( 1 ), [Me 2 SnL 2 ] n ( 2 ), [Me 2 SnL 3 ] ( 3 ), [Ph 3 SnL 1 H] n ( 4 ) and [Ph 3 SnL 3 H] ( 5 ) (where L 1 = (2 S )-2-(( E )-(( Z )-4-hydroxypent-3-en-2-ylidene)amino)-3-(1 H -indol-3-yl)propanoate, L 2 = (2 S )-( E )-2-((2-hydroxybenzylidene)amino)-3-(1 H -indol-3-yl)propanoate and L 3 = (2 S )-( E )-2-((1-(2-hydroxyphenyl)ethylidene)amino)-3-(1 H -indol-3-yl)propanoate were synthesized and spectroscopically characterized. The crystal structures of 1 – 4 were determined. For the dimethyltin derivative 2 , a polymeric chain structure was observed as a result of a long Sn∙∙∙O contact involving the exocyclic carbony…
DNA binding and antiproliferative activity toward human carcinoma cells of copper(ii) and zinc(ii) complexes of a 2,5-diphenyl[1,3,4]oxadiazole deriv…
2012
The interaction of calf thymus DNA with [CuL(ClO(4))]ClO(4)·H(2)O (1) and [ZnLBr]Br·H(2)O (2) (L = 9,12,15,18,27,28-hexaaza-29-oxatetracyclo[24.2.1.0(2,7).0(20,25)]enneicosa-2,4,6,20,22,24,26,28(1)-octaene) dicationic complexes in aqueous solution at neutral pH, was investigated by variable-temperature UV-vis absorption, circular dichroism and fluorescence spectroscopy. The values of the DNA-binding constants of these complexes, determined by competitive binding spectrofluorimetric titrations of ethidium bromide (EB)-DNA solutions, are (6.7 ± 0.5) × 10(6) M(-1) for CuL(2+) and (4.7 ± 0.5) × 10(5) M(-1) for ZnL(2+). These data together with a through analysis of the spectroscopic behaviour c…
Selective "one-pot" synthesis of functionalized cyclopentenones.
2012
Double addition (1,2-1,4) of vinyl magnesium bromide to squaric acid derivatives allows the preparation of polyoxygenated cyclopentenones (8) in a "one-pot" procedure. The reaction occurs through the intermediate formation of octatetraenes (6). Protonation of this latter intermediate at -78 °C with TFE occurs selectively at the vinyl CH(2) closer to the metallic centers. DFT studies of the cyclization step justify the observed diastereoselectivity.