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991.
Maity S Jana P Maity SK Haldar D 《Langmuir : the ACS journal of surfaces and colloids》2011,27(7):3835-3841
This paper presents the construction of hollow peptide microspheres and the mechanism of transition of microspheres to rod-like vesicles at low concentration. The tripeptides Boc-Phe-Maba-Phe-OMe 1 and Boc-Phe-Maba-Tyr-OMe 2, each of them containing a rigid m-aminobenzoic acid (Maba) template at the central position, forms microspheres at a concentration of 1.6 mM in methanol. At low concentration, these vesicular structures are fused through neck formation, and this leads to sphere-to-rod transition of vesicles. Sizes of these microspheres increase with increasing concentration. We have successfully characterized this transition by fluorescence spectroscopy, DLS, and electron microscopic study. The scanning electron microscopy clearly shows that these spheres are hollow. One important property of these microvesicular structures is the encapsulation of a potent anticonvulsant and mood stabilizing drug carbamazepine, which holds future promise to use these microvesicles as delivery vehicles. 相似文献
992.
The potential of near infrared (NIR) spectroscopy in characterization of organically modified clay minerals is introduced. Selected organo-clays, possibly perspective fillers in clay polymer nanocomposites, were prepared from Na-montmorillonite and different surfactants containing octylammonium chain(s), hexadecylammonium chain(s) or a benzene ring with or without a reactive double bond. Based on the stretching (ν) and bending (δ) vibrations observed in the middle IR (MIR) region, the first overtone (2νXH) and combination (ν + δ)XH modes of XH groups (X = O, C, N) are identified. The effect of larger alkylammonium cations on the vibrations of Si-O and OH bonds in montmorillonite layers is observed. The changes in the intensity of the (ν + δ)H2O band near 5250 cm−1 allows for comparison of the amount of water adsorbed on the montmorillonite surface. The water content decreases with the size of the organic cation reflecting increasing hydrophobicity of the montmorillonite surface. The NIR region shows the 2νCH3 and 2νCH2 bands in the 5900-5500 cm−1 region, an upward shift is observed for the complex band due to 2νCH(Ar) of aromatic benzene ring. The NIR spectra are extremely useful in identification of NH2+, NH+ and vinyl groups, which are difficult to recognize in the MIR spectra of organo-clays due to overlapping with other absorption bands. The intense bands corresponding to overtones and combination vibrations of NH3+ and NH2+ groups are found in the 6600-6050 cm−1 and 5000-4600 cm−1 regions, the (ν + δ)NH+ is unambiguously identified near 4750 cm−1. The characteristic band assigned to 2νCH2 in H2CC is detected near 6130 cm−1. 相似文献
993.
Sarish SP Nekoueishahraki B Jana A Roesky HW Schulz T Stalke D 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(3):890-894
[L1AlMe]?THF ( 1 ; L1=CH[C(CH2)](CMe)(2,6‐iPr2C6H3N)2) is prepared by a new method to test its reactivity towards metal complexes to give heterobimetallic or polymetallic complexes. The treatment of 1 with germanium chloride ([LGeCl]), tin chloride ([LSnCl]; L=CH(CMe2,6‐iPr2C6H3N)2), bismuth amide ([1,8‐C10H6(NSiMe3)2BiNMe2]), and dimethyl zinc (ZnMe2) gave the desired compounds with different functional groups on the aluminum center. All compounds have been thoroughly characterized by multinuclear NMR spectroscopy, EI mass spectrometry, X‐ray crystallography ( 2 , 3 , and 5 ), and elemental analysis. 相似文献
994.
Dytrtová JJ Jakl M Schröder D Čadková E Komárek M 《Rapid communications in mass spectrometry : RCM》2011,25(8):1037-1042
Electrospray ionization mass spectrometry (ESI-MS) is used to probe the complex formation between tebuconazole (1) and copper(II) salts, which both are commonly used fungicides in agriculture. Experiments with model solutions containing 1 and CuCl(2) reveal the initial formation of the copper(II) species [(1)CuCl](+) and [(1)(2)CuCl](+) which undergo reduction to the corresponding copper(I) ions [(1)Cu](+) and [(1)(2)Cu](+) under more drastic ionization conditions in the ESI source. In additional experiments, copper/tebuconazole complexes were also detected in samples made from soil solutions of various origin and different amount of mineralization. The direct sampling of such solutions via ESI-MS is thus potentially useful for understanding of the interactions between copper(II) salts and tebuconazole in environmental samples. 相似文献
995.
Dominika Veselinyov Jana Malankov Katarina Kalinov Helena Mi
kov Mria Marekov Miroslava Rabajdov 《Molecules (Basel, Switzerland)》2021,26(13)
We are experiencing rapid progress in all types of imaging techniques used in the detection of various numbers and types of mutation. In situ hybridization (ISH) is the primary technique for the discovery of mutation agents, which are presented in a variety of cells. The ability of DNA to complementary bind is one of the main principles in every method used in ISH. From the first use of in situ techniques, scientists paid attention to the improvement of the probe design and detection, to enhance the fluorescent signal intensity and inhibition of cross-hybrid presence. This article discusses the individual types and modifications, and is focused on explaining the principles and limitations of ISH division on different types of probes. The article describes a design of probes for individual types of in situ hybridization (ISH), as well as the gradual combination of several laboratory procedures to achieve the highest possible sensitivity and to prevent undesirable events accompanying hybridization. The article also informs about applications of the methodology, in practice and in research, to detect cell to cell communication and principles of gene silencing, process of oncogenesis, and many other unknown processes taking place in organisms at the DNA/RNA level. 相似文献
996.
In this paper we have investigated the propagation characteristics of optical solitons in dispersion managed optical communication systems taking into account of the effect of quintic nonlinearity. Using variational formalism, several ordinary differential equations have been established for pulse parameters. These equations have been solved numerically to investigate the propagation characteristics. It has been noticed that stable periodic pulse propagation is possible over long distance. Numerical simulation has been undertaken to show that parabolic nonlinearity reduces collision distance between neighbouring pulses of the same channel. 相似文献
997.
Jana Páleníková Michal Kraus Pavel Neogrády Miroslav Urban 《Molecular physics》2013,111(20):2333-2344
Geometries, excitation energies, dipole moments and dipole polarisability tensor components of the ground and four lowest excited states 3 B 1, 1 B 1, 3 A 2, 1 A 2 of the H2O and H2S molecules were calculated at the CASSCF, CASPT2, CCSD and CCSD(T) level of approximation. Vertical excitation and equilibrium transition energies of these states, having the Rydberg character, are reported too. Properties of both molecules in the ground and in low lying excited states are compared and discussed from the point of view of their molecular electronic structure. Upon excitation we observe dramatic changes of dipole moments and polarisabilities with respect to the ground state. We stress the change of the polarity of H2O in all excited states accompanied by the enhancement of the dipole polarisability by an order of magnitude. Large, even if less pronounced, are changes of electric properties of H2S in its excited states. Dipole moments and dipole polarisabilities of 3 B 1, 1 B 1 states of H2S and H2O behave quite analogously in comparison to their respective ground state. The general pattern of properties for both molecules in their 3 A 2 and 1 A 2 excited states is more different due to a pronounced participation of the sulphur d-orbitals in these states of the H2S molecule. 相似文献
998.
Dana Gabrovská Jarmila Ouhrabková Jana Rysová Ivana Laknerová Vlasta Fiedlerová Marie Holasová 《高压研究》2013,33(1):103-113
The aim of this work was to find sensory suitable combinations of not commonly used vegetables, that is, cabbage, celeriac and parsnip, into mixed fruit–vegetable juices, two-species vegetable juices and vegetable juices with whey. These juices might have the potential to offer consumers new, interesting, tasty and nutritional products. Another interesting variation could be preparation of vegetable juices in combination with sweet whey. Nutritional and sensory evaluations were carried out using juices prepared in the laboratory. The total phenolic content, in addition to ascorbic acid and antioxidant activity, was determined. The developed juices with high nutritional value should increase very low fruit and vegetable consumption in the Czech population. The prepared juices were high pressure pasteurized (410 MPa). This technique retains the desired levels of important nutritional substances, while being destructive to live microbial cell structure. The germination of spores is suppressed by low pH value. 相似文献
999.
Štefan Tóth Jr. Tímea Pekárová Vladimíra Tomečková Jana Mašlanková Miroslava Bilecová-Rabajdová Marián Tomečko 《光谱学快报》2014,47(3):238-243
The aim of this study was to evaluate endogenous fluorescence of small intestine samples and compare them with the histopathological results. The autofluorescence of intestinal homogenates and histopathological injury index after 1h of mesenteric or portal ischemia, and 1 or 24 hours of reperfusion was analysed. Our results revealed two maximum peaks on the EEM. Increase of the intestinal histopathological injury index was accompanied with significant increase of fluorescence intensities in both zones. Close correlation between autofluorescence and histopathological results was found. Autofluorescence can be used was revealed suggesting use of autofluorescence as a new diagnostic method of intestinal injury. 相似文献
1000.
Gane P. A. C. Ridgway C. J. Kijevčanin M. Stijepović M. Uskoković P. S. Barać N. Dimić-Mišić K. Imani M. Janaćković D. Barceló E. 《Transport in Porous Media》2021,138(3):539-576
Transport in Porous Media - A novel surface-flow filter has been designed to take advantage of a combination of both diffusion and lateral flow permeation, since active coatings, even if porous,... 相似文献