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131.
Lou DW Saito Y Zarzycki PK Ogawa M Jinno K 《Analytical and bioanalytical chemistry》2006,385(1):96-104
An improved high-performance liquid chromatographic method for separation of a number of ginsenosides has been developed.
The influence of temperature (from 0 to 25°C) on the retention and separation of the ginsenosides was studied by applying
a binary mobile phase (acetonitrile/water, 82:18 v/v) and a diol column (LiChrospher 100 Diol). The column temperature is
one of the more important parameters for the retention and separation of the components investigated. Selected thermodynamic
parameters, including changes of enthalpy (ΔH°) and entropy (ΔS°), were estimated from linear van’t Hoff plots, and possible retention mechanisms were discussed. Moreover, the best separation
conditions were selected based on optimization criteria including maximum retention time (t
R max), minimum resolution (R
s
min), and relative resolution product (r). Temperature regions close to 14°C offered the highest selectivity and almost equal distribution of the ginsenosides peaks
across the chromatogram. Under such isocratic conditions, excellent separation of chromatographic standards and selected ginseng
samples was achieved in less than 16 min. 相似文献
132.
Okuda M Suzumoto Y Iwahori K Kang S Uchida M Douglas T Yamashita I 《Chemical communications (Cambridge, England)》2010,46(46):8797-8799
We report here, for the first time, a biotemplated synthesis of uniform CdSe nanoparticle (4.1 ± 0.5 nm) and a fabrication of two-dimensional CdSe nanoparticles (over one micrometre) with nanometric gaps by cage-like protein, Listeria-Dps. 相似文献
133.
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136.
A novel in-needle extraction device has been developed for the preconcentration of gaseous organic compounds prior to the determination in gas chromatography (GC). As the extraction medium, a copolymer of methacrylic acid and ethylene glycol dimethacrylate was synthesized. Based on the results in the preliminary experiments, the desorption conditions such as desorption temperature and time have been optimized along with the evaluation of the extraction efficiency. The storage performance of the needle extraction device was also studied. The results clearly demonstrated the excellent extraction performance for typical organic solvents and also suggested the future possibility such as in the applications for the analysis of working environments. 相似文献
137.
Atsumi FUKUDA Eiki TSUSHIMA Kanichiro WADA Yasuyuki ISHIBASHI 《Physical Therapy Research》2020,23(2):132
Objective: To examine the changes in postural alignment and kyphosis-correlated factors after 6 months of back extensor strengthening exercise in a group of community-dwelling older adults aged ≥65 years. Methods: We quasi-randomized 29 subjects into an intervention group treated with a back extensor strengthening program and a control group treated with a full-body exercise program. These groups completed 20-30 minutes of exercise directed by a physical therapist one or more times per week and were instructed to exercise at home as well. The participants were assessed prior to and after the intervention using the following criteria: postural alignment of “usual” and “best” posture, physical function, physical performance, self-efficacy, and quality of life. The differences between two factors (group and period) were compared for each of the measurement variables. Results: Subjects who adequately completed the exercises were analyzed. A reduced knee flexion angle was noted in the “best” posture of both groups, as were improved physical function and performance with the exception of one-leg standing time. Verifying the effect size in the post-hoc analysis, the body parts that showed changes to postural alignment after the intervention differed between groups. Conclusions: Back extensor strengthening exercises improved physical function and performance, but did not improve spinal alignment. The changes due to these interventions were not significantly different from changes observed in the full-body exercise group. However, post-hoc analysis revealed that the effect size of posture change was different, possible indicating that the two groups experienced different changes in the postural alignment. 相似文献
138.
Oshio H Nihei M Koizumi S Shiga T Nojiri H Nakano M Shirakawa N Akatsu M 《Journal of the American Chemical Society》2005,127(13):4568-4569
The tetranuclear complex [MnIII2NiII2Cl2(salpa)2] (salpa = N-(2-hydroxybenzyl)-3-amino-1-propanol) has a spin ground state of S = 6 and was confirmed to be an SMM based on a steplike feature of the magnetization hysteresis loop at 0.55 K. 相似文献
139.
Wakako Kasai Keisuke Tsutsumi Mitsuhiro Morita Tetsuo Kondo 《Colloid and polymer science》2008,286(6-7):707-712
An arrangement for the long alkyl side chains in a Langmuir–Blodgett (LB) film from regioselectively alkylated 2,3-di-O-octadecylcellulose on an Au-coated substrate was investigated using Fourier transform infrared reflection absorbance spectroscopy. The IR results indicated that the hydrophobic long alkyl side chains were forced to be repellent to the surface of water, resulting in deposition on the substrate, with it being tilted in the vertical direction, and further formed both hexagonal and orthorhombic crystalline structures up to 10 layers in the LB film. In addition, molecular modeling with CAChe software indicated that the optimized assembly of the side chains was supposed to own a vertical arrangement against the substrate surface after compression of the monolayer. This means that the conformation of 21 screw of the cellulose molecular chain may be altered by the compression to have an unusual conformation by a different φ–ψ dihedral angle such as onefold axis without a symmetry element. 相似文献
140.
Mitsuhiro Kanakubo Tomoyuki Uda Haruko Ikeuchi Gen P. Satô 《Journal of solution chemistry》1998,27(7):645-653
Cobalt-59 NMR chemical shifts of Co(acac)3, and Co(dpm)3 (acac– = acetylacetonate ion and dpm– = dipivaloylmethanate ion) in 14 organic solvents, C6H14, C6H6, CH2Cl2, CHCl3, CCl4, CH3CN, CH3OH, C2H5OH, CH3CH(OH)CH3, (C2H5)2O, (CH3)2CO, (CH3)2SO, (CH3)2NCHO and C6H5NO2, were measured at five temperatures ranging from 289 to 329 K. The observed chemical shift (obs) was linearly correlated to the maximum absorption wavelength in the visible spectra (max) corresponding to the d-d electronic transition energy between the ground 1A1g and excited 1T1g states. The obs-max relation was explained by the ligand field theory. The temperature coefficients of obs, of each complex showed a negative correlation with obs. The obs, of Co(acac)3 decreased with the increasing electrophilic ability of the solvent (Mayer's acceptor number), whereas no tendency was observed in the case of Co(dpm)3. 相似文献