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91.
Ta Chen Chen Song-Cu Yu Chin-Mu Hsu Fuu-Jen Tsai Yuhsin Tsai 《Journal of inclusion phenomena and macrocyclic chemistry》2017,88(1-2):27-34
Minoxidil dissolved in organic solvents is commonly used in the treatment of androgenic alopecia because it is hydrophobic and poorly soluble in water. The aim of this investigation was to develop an aqueous minoxidil solution without addition of organic solvents. To this end, minoxidil was encapsulated in 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) to form a minoxidil–HP-β-CD inclusion complex with aqueous solubility higher than that of pure minoxidil. Minoxidil–HP-β-CD inclusion complexes were prepared using a freeze-drying method from minoxidil and HP-β-CD at a molar ratio of 1:1. Complex formation was confirmed by nuclear magnetic resonance, thermogravimetric analysis, and thin layer chromatography. The structure of the complex was determined using two-dimensional rotating frame overhauser effect spectroscopy. Minoxidil–HP-β-CD inclusion complexes were dissolved in water to form a homogeneous aqueous solution, and its effect on the hair cycle of mice was evaluated in vivo. The results support the feasibility of using HP-β-CD to prepare an aqueous minoxidil solution to replace organic solvent-based solutions. 相似文献
92.
93.
Electrodeposition technique was used in order to produce nanometric zinc oxide films on glass insulating substrates. The effect of electrolyte concentration and applied current density on the formation and growth of electrodeposited Zn thin films in aqueous solutions of ZnSO4 were studied. After a thermal oxidation, a characterization of the structural morphology of the films deposited was carried out by optical microscopy (OM), atomic force microscopy (AFM), scanning electron microscopy (SEM) and by grazing incidence X-rays diffraction (GIXD). These characterization techniques show that the grains size of the films after oxidation at temperature 450 °C is between 5 and 15 nm, as well as the structure is polycrystalline nature with several orientations. UV/vis spectrophotometry confirms that it is possible to obtain transparent good ZnO films with an average transmittance of approximately 80% within the visible wavelength region, as well as the optical gap of obtained ZnO films is 3.17 eV. 相似文献
94.
Various compositions (1−x)BaTiO3 + xPbF2 + xLiF were prepared, shaped to pellets then sintered at 900°C for 2 h in gold sealed tubes. The purity and the symmetry of the
obtained samples were checked by X-ray diffraction. A new solid solution with Ba1−x
Pb
x
(Ti1−x
Li
x
) O3−3x
F3x formula occurs in the composition range 0 ≤ x ≤ 0.20. SEM observations were performed on polished and fractured ceramics. The complex permittivity was measured as a function
of temperature (−120°C ≤ T ≤ 250°C) and frequency (50 Hz ≤ f ≤ 4 × 107 Hz). The dielectric performances are the best for ceramic Ba0.97Pb0.03(Ti0.97Li0.03)O2.91F0.09. The real component ε′, exhibits a maximum of approximately 7500 at the ferroelectric Curie temperature T
C
≈ -18°C, the dielectric losses tan δ value being 0.012. At room temperature, the relaxation frequency f
r
is around 40 MHz for this ceramic. This novel ferroelectric oxifluoride is a promising material for applications, in particular
in the field of Z5U multilayer capacitors.
相似文献
95.
The oxidation of n-propanol and n-butanol to their corresponding aldehydes was monitored by the pervaporation technique. Mass transfer phenomenon that occurs in the pervaporation process was confirmed by the results of inverse gas chromatography. Polydimethylsiloxane (PDMS), a hydrophobic polymer widely employed as a membrane in pervaporation technique, was evaluated as a stationary phase in this study. The retention times of the different molecules probes (n-propanol, n-butanol, propionaldehyde, and butyraldehyde), molecules involved as reactants and products in the oxidation reaction, gave an insight into the extent of the interactions between each of these molecules and the stationary phase. The infinite dilution conditions allowed to measure the infinite dilution activity coefficient, gamma(infinity), and the specific retention volume, V(g)(0), and to estimate the Flory-Huggins parameter interactions, chi(12)(infinity). The magnitudes of these parameters threw some light on the permselectivity of the membranes in the pervaporation operation. 相似文献
96.
The hollow cylinder model filled with viscous-liquid is performed to simulate tibial bone shape in this paper. Short time Fourier transform (STFT) was applied to identify and analyze guided wave modes of a series of ultrasonic signals acquired at various transmitter-receiver positions for a fixed transmitter. Experimental results were compared with theoretical simulation. The high correlation values for group velocity were obtained between results of experiment and theory for L(0,2) (r=0.89, p<10(-5)), and L(0,3) (r=0.87, p<10(-5)). The experimental group velocities correlated strongly with cortical thickness (cortTh) for L(0,2) (r(2)=0.79, p<10(-5)) and L(0,3) (r(2)=0.74, p<10(-5)) at 0.5 MHz center frequency. The results showed that the STFT is an effective method to identify the propagating modes and derive dispersion information. The experimental results were in good agreement with theoretical predictions. This study suggests that the guided wave L(0,2) mode is a promising mode to assess change in cortical thickness. 相似文献
97.
A novel combined spectral estimate (CSE) method for differentiation and estimation the phase velocities of multimode Lamb waves whose wave numbers are much close or overlap one another in multiplayer plates is presented in this paper, which based on auto-regressive (AR) model and 2-D FFT. Simulated signals in brass plate were processed by 2-D FFT and CSE. And experiments are performed by using two conventional angle probes as emitter and receiver on the same surface of three-layered aluminum/xpoxy/aluminum plates, which include symmetrical and unsymmetrical plates. The multimode Lamb waves are excited in these laminates, and the received signal is processed by 2-D FFT and CSE, respectively. The results showed that the phase velocities of multimode signals whose wave numbers are much closed cannot be differentiated by 2-D FFT, but CSE has strong spatial resolution. Compared the measured phase velocities with the theoretical values, the error is smaller than 2% on the whole. It promises to be a useful method in experimental signals processing of multimode Lamb waves. 相似文献
98.
The Ryser Conjecture which states that there is a transversal of size in a Latin square of odd order is equivalent to finding a rainbow matching of size in a properly edge-colored using colors when is odd. Let be the minimum degree of a graph. Wang proposed a more general question to find a function such that every properly edge-colored graph of order contains a rainbow matching of size , which currently has the best bound of by Lo. Babu, Chandran and Vaidyanathan investigated Wang’s question under a stronger color condition. A strongly edge-colored graph is a properly edge-colored graph in which every monochromatic subgraph is an induced matching. Wang, Yan and Yu proved that every strongly edge-colored graph of order at least has a rainbow matching of size . In this note, we extend this result to graphs of order at least . 相似文献
99.
Sülin Taşcioglu Rajat Ismailov 《Journal of inclusion phenomena and macrocyclic chemistry》1996,26(1-3):73-82
Copper (II) complexes ofN-salicylideneanthranilic acid (I) and its derivatives (II, III) as well as their NaBH4 reduction products, namelyN-(2-hydroxybenzyl) anthranilic acids (IV–VI) have been prepared and their structures have been determined analytically. Tetracoordinated planar structures of the Cu(II) complexes of the Schiff bases and distorted tetrahedral structures of the Cu(II) complexes of compoundsV–VI have been elucidated by ESR and other spectral methods. During the preparation of the complex the hydrolysis of the Schiff base often takes place in the presence of water giving anthranilates and salicylaldehydates of metals to some extent along with the complexes of the Schiff base. The kinetic data for the hydrolysis ofN-salicylideneanthranilic acid (I) in methanol-water solution also are reported.Presented at the Sixth International Seminar on Inclusion Compounds, Istanbul, Turkey, 27–31 August, 1995. 相似文献
100.
A. Savaşer S. Goraler A. Taşöz B. Uslu H. Lingeman S. A. Özkan 《Chromatographia》2007,65(5-6):259-265
A simple, accurate, precise and fully automated method for the simultaneous determination of abacavir, lamivudine and zidovudine in pharmaceutical tablets, human serum samples and drug dissolution studies has been developed. Separation was performed on a 5 μm Zorbax® C18 column (150 × 4.6 mm ID) with methanol:water:phosphate buffer at pH 5.65 (80:10:10; v/v/v) isocratic elution in less than 7 min with a flow rate of 0.6 mL min?1.Good sensitivity for all analytes was observed with UV detection at 275 nm. The method allowed quantitation over the 500–3,000 ng mL?1 range for abacavir and 500–5,000 ng mL?1 range for lamivudine and zidovudine. The method has been applied, without any interference from excipients or endogenous substances, for the simultaneous determination of these three compounds in tablets. Human serum and drug dissolution studies. 相似文献