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131.
132.
C. Carnero Ruiz L. Díaz‐López J. Aguiar 《Journal of Dispersion Science and Technology》2013,34(2):266-273
The effect of glycerol on both micellar formation and the structural evolution of the sodium dodecyl sulfate (SDS) aggregates in the context of the action mechanism of the cosolvent has been studied. The critical micelle concentration and the degree of counterion dissociation of the surfactant over a temperature range from 20°C to 40°C were obtained by the conductance method. The thermodynamic parameters of micellization were estimated by using the equilibrium model of micelle formation. The analysis of these parameters indicated that the lower aggregation of the surfactant is mainly due to a minor cohesive energy of the mixed solvent system in relation to the pure water. The effect of glycerol on the mean aggregation number of the micelles of SDS was analyzed by the static quenching method. It was found that the aggregation number decreased with the glycerol content. This reduction in the micellar size seems to be controlled by an increase in the surface area per headgroup, which was ascribed to a participation of glycerol in the micellar solvation layer. Studies on the micropolarity of the aggregates, as sensed by the probe pyrene, indicated that this microenvironmental parameter is almost unaffected by the presence of glycerol in the mixture. However, an increase in the micellar microviscosity at the surface region was observed from the photophysical behavior of two different probes, rhodamine B and auramine O. These results suggest a certain interaction of the cosolvent in the micellar solvation of SDS micelles. 相似文献
133.
Meili Duan Takeyasu Tasaka Hiroaki Okamoto Vladimir F. Petrov Shunsuke Takenaka 《Liquid crystals》2013,40(9):1195-1205
This paper describes the effect of substituent and ester linkage on smectic properties for some derivatives of 4-R -phenyl 4-(4-octyloxybenzoyloxy)benzoates (1), 4-octyloxyphenyl 4-(4-R-benzyloxy)benzoates (2), 4-(4-octyloxybenzoyloxy)phenyl 4- R -benzoates (3), and 4-R-phenyl 4-octyloxyphenyl terephthalates (4) where R = OCH3, CH3, OC8H17, C8H17, halogens, CF3, OCF3, CN, NO2, etc. The thermal properties are discussed in terms of the electrostatic nature of the substituents and the relative orientation of the ester groups with respect to both terminal substituents. The substituent effect on the layer structure of the smectic A phase is also examined by means of a small angle X-ray analysis. 相似文献
134.
Qiu-Juan Ma Xiao-Bing Zhang Zhi-Xiang Han Bo Huang Qin Jiang Guo-Li Shen 《International journal of environmental analytical chemistry》2013,93(1):74-86
A ratiometric fluorescent zinc probe 1 of carboxamidoquinoline with a carboxylic acid group was designed and synthesised. Probe 1 exhibits high selectivity for sensing Zn2+; about a 13-fold increase in fluorescence emission intensity and an 82?nm red-shift of fluorescence emission are observed upon binding Zn2+ in EtOH/H2O (1?:?1, V/V) solution. The ratiometric fluorescence response is attributed to the 1?:?1 complex formation between probe 1 and Zn2+ which has been utilised as the basis for the selective detection of Zn2+. The analytical performance characteristics of the proposed Zn2+-sensitive probe were investigated. The linear response range covers a concentration range of Zn2+ from 2.0?×?10?6 to 5.0?×?10?5?mol?L?1 and the detection limit is 2.7?×?10?7?mol?L?1. The determination of Zn2+ in both tap and river water samples shows satisfactory results. 相似文献
135.
Precise characterization method of antibody‐conjugated magnetic nanoparticles for pathogen detection using stuffer‐free multiplex ligation‐dependent probe amplification
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Boram Chung Gi Won Shin Woong Choi Jinmyoung Joo Sangmin Jeon Gyoo Yeol Jung 《Electrophoresis》2014,35(23):3283-3289
Antibody‐conjugated magnetic nanoparticles (Ab‐MNPs) have potential in pathogen detection because they allow target cells to be easily separated from complex sample matrices. However, the sensitivity and specificity of pathogen capture by Ab‐MNPs generally vary according to the types of MNPs, antibodies, and sample matrices, as well as preparation methods, including immobilization. Therefore, achieving a reproducible analysis utilizing Ab‐MNPs as a pathogen detection method requires accurate characterization of Ab‐MNP capture ability and standardization of all handling processes. In this study, we used high‐resolution CE‐single strand conformational polymorphism coupled with a stuffer‐free multiplex ligation‐dependent probe amplification system to characterize Ab‐MNPs. The capture ability of Ab‐MNPs targeting Salmonella enteritidis and nine pathogens, including S. enteritidis, was analyzed in phosphate buffer and milk. The effect of storage conditions on the stability of Ab‐MNPs was also assessed. The results showed that the stuffer‐free multiplex ligation‐dependent probe amplification system has the potential to serve as a standard characterization method for Ab‐MNPs. Moreover, the precise characterization of Ab‐MNPs facilitated robust pathogen detection in various applications. 相似文献
136.
Rapid and sensitive detection of lower respiratory tract infections by stuffer‐free multiplex ligation‐dependent probe amplification
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Boram Chung Gi Won Shin Chan Kwon Park Woong Choi Yeun‐Jun Chung Hyung Kyu Yoon Gyoo Yeol Jung 《Electrophoresis》2014,35(4):511-514
Lower respiratory tract infection is one of the most common infectious diseases. However, conventional methods for detecting infectious pathogens are time‐consuming, and generally have a limited impact on early therapeutic decisions. We previously reported a rapid and sensitive method for detecting such pathogens using stuffer‐free multiplex ligation‐dependent probe amplification coupled with high‐resolution CE‐SSCP. In this study, we report an application of this method to the detection of respiratory pathogens. As originally configured, this method was capable of simultaneously detecting seven bacterial species responsible for lower respiratory tract infections, but its detection limit and assay time were insufficient to provide useful information for early therapeutic decisions. To improve sensitivity and shorten assay time, we added a target‐specific preamplification step, improving the detection limit from 50 pg of genomic DNA to 500 fg. We further decreased time requirements by optimizing the hybridization step, enabling the entire assay to be completed within 7 h while maintaining the same detection limit. Taken together, these improvements enable the rapid detection of infectious doses of pathogens (i.e. a few dozen cells), establishing the strong potential of the refined method, particularly for aiding early treatment decisions. 相似文献
137.
Olimpo García-Beltrán Bruce K. Cassels Natalia Mena Marco T. Nuñez Osvaldo Yañez Julio Caballero 《Tetrahedron letters》2014
In this Letter we present a new probe, (E)-7-(diethylamino)-2-oxo-2H-chromene-3-carbaldehyde oxime (JB), which can detect Cu2+ ions in HEPES buffer under physiological conditions. Benesi–Hildebrand and Job plots demonstrate that the stoichiometry of the Cu2+ complex formed is 2:1. Possible interference with other analytes was examined, and the decrease of the fluorescence of JB at 510 nm when it reacts with Cu2+ was shown to be highly selective. This probe accumulates in the plasmalemma of human neuroblastoma SH-SY5Y cells. Molecular dynamics (MD) simulations revealed that JB interacts with the lipid bilayer at the level of the glycerol moieties. 相似文献
138.
《Comptes Rendus Chimie》2014,17(5):477-483
The ligand Hbpq = N-(8-quinolyl)pyridine-2-carboxamide) has been prepared using tetrabutylammonium bromide (TBAB) as an environmentally friendly reaction medium. Four new complexes of this ligand, [M(bpq)X] (M = Cu(II), X = SCN̄ (1), N3̄ (2); M = Ni(II), X = SCN̄ (3), N3̄ (4)), have also been synthesized and fully characterized. The crystal and molecular structures of [Cu(bpq)(NCS)]n (1) have been determined by X-ray crystallography. Copper(II) ion adopts a distorted square pyramidal (4 + 1) coordination in this complex. Hbpq ligand shows a strong emission at 500 nm in acetonitrile solution. The emission is quenched in the presence of copper(II) acetate, apparently because of the formation of [Cu(L)(OAc)(H2O)] complex. Introduction of nitric oxide (NO) into the acetonitrile solution at room temperature induces an increase in the fluorescence intensity, presumably due to the reduction of Cu(II) to Cu(I). This process is reversible and can form a basis for direct detection of NO. 相似文献
139.
140.