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971.
Petradza M Akerlof C Chapman J Errede D Ken MT Meyer DI Neal H Nitz D Thun R Tschirhart R Abachi S Derrick M Kooijman P Price LE Repond J Sugano K Cork B Blockus D Brabson B Brom JM Jung C Ogren H Rust DR Baringer P Bylsma BG DeBonte R Koltick D Low EH McIlwain RL Miller DH Ng CR Shibata EI 《Physical review D: Particles and fields》1990,42(7):2180-2186
972.
973.
Abachi S Derrick M Kooijman P Musgrave B Price LE Repond J Sugano K Waschbusch P Blockus D Brabson B Brom JM Jung C Ogren H Rust DR Akerlof C Chapman J Errede D Ken MT Meyer DI Neal H Nitz D Thun R Tschirhart R Baringer P Bylsma BG DeBonte R Koltick D Low EH McIlwain RL Miller DH Ng CR Shibata EI Cork B 《Physical review D: Particles and fields》1989,40(3):706-711
974.
975.
A method for determination of riboflavin in animal feeds using liquid chromatography (LC) was developed for feed samples fortified with riboflavin at 1 mg/lb or greater (up to 10,000 mg/lb). Feed samples were extracted in 0.1 N HCl with heating on a steam bath for 30 min, followed immediately by mechanical shaking for 30 min. Sample extracts were diluted to target volume with 2% acetic acid and filtered; riboflavin was determined by LC on a reversed-phase C18 column with 2% acetic acid-acetonitrile (85 + 15) mobile phase for separation and fluorescence detection with excitation at 460 nm and emission at 530 nm. The extraction was compared with that of the AOAC Official Method for riboflavin in food and feed premixes. The 2 method extractions were not significantly different from each other at the 95% confidence level. The developed method also had good linearity over 4 orders of magnitude, recovery of 95-99% from spiked feed samples, a limit of detection of riboflavin at 0.00034 microg/mL in solution, a limit of quantitation of 0.023 mg/lb in feed, and good ruggedness. 相似文献
976.
On-line two-angle (15° and 90°) light scattering measurements with a gel permeation chromatography for linear and branched polystyrene in tetrahydrofuran (a good solvent) and in trans-decalin (a theta solvent) were made and compared with data from a multi-angle light scattering detector and literature values. Theoretically, weight-average molecular weight and the radius of gyration Rg can be determined accurately in the range where Rg2k2 is less than 1.2 (rod)∼1.7 (random coil); here, k is the absolute value of the scattering vector for a right angle detector with the Berry square root method. Molecular weight dependence of the radius of gyration obtained from the two-angle light scattering detector for linear and branched polystyrenes under different thermodynamic conditions were measured and found to be almost the same as values measured with a multi-angle light scattering detector and literature values in the appropriate range of molecular weight. 相似文献
977.
A convenient modified short‐cut route for the preparation of a 32‐membered octaazamacrocyclic molecule, 1,5,9,13,17,21,25,29‐octaazacyclodotriacontane hydrochloride, [32]ane‐N8·8HCl has been described. The proper tetramine has been contemplated to go this new pathway which propagates [32]‐N8·8HCl more effectively. 相似文献
978.
Gold‐Catalyzed Enantioselective Synthesis,Crystal Structure,and Photophysical/Chiroptical Properties of Aza[10]helicenes
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Maya Tanaka Dr. Yu Shibata Kyosuke Nakamura Kota Teraoka Prof. Dr. Hidehiro Uekusa Dr. Kazuko Nakazono Prof. Dr. Toshikazu Takata Prof. Dr. Ken Tanaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(28):9537-9541
The enantioselective synthesis of an aza[10]helicene, possessing two pyridone units, has been achieved by the gold‐catalyzed intramolecular quadruple hydroarylation of a tetrayne. This aza[10]helicene was successfully converted into a fully aromatic aza[10]helicene, possessing two pyridine units. Structure–photophysical and chiroptical properties relationship in a series of azahelicene isomers has also been disclosed. 相似文献
979.
Abdou Tchoukoua Turibio Kuiate Tabopda Shota Uesugi Ken‐ichi Kimura Eunsang Kwon Hiroyuki Momma Bonaventure Tchaleu Ngadjui Takuya Koseki Yoshihito Shiono 《Magnetic resonance in chemistry : MRC》2016,54(11):893-896
Phytochemical investigation of the roots of Albizia chevalieri led to the isolation of two new 5‐deoxyflavan‐3,4‐diol glucosides from roots of A. chevalieri, Chevalieriflavanosides A and B. Their structures were established by 2D NMR techniques, UV, IR, CD, and mass spectrometry. Cytotoxicity of the two compounds was evaluated against acute promyelocytic leukemia HL60 cells. The antibacterial activities of 1 and 2 also were evaluated against Pseudomonas aeruginosa and Staphylococcus aureus using the agar diffusion test. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
980.
In the present study the natural abundance of 13C is quantified in agricultural soils in Mexico which have been submitted to different agronomic practices, zero and conventional tillage, retention of crop residues (with and without) and rotation of crops (wheat and maize) for 17 years, which have influenced the physical, chemical and biological characteristics of the soil. The natural abundance of C13 is quantified by near infrared spectra (NIRS) with a remote reflectance fibre optic probe, applying the probe directly to the soil samples.Discriminate partial least squares analysis of the near infrared spectra allowed to classify soils with and without residues, regardless of the type of tillage or rotation systems used with a prediction rate of 90% in the internal validation and 94% in the external validation. The NIRS calibration model using a modified partial least squares regression allowed to determine the δ13C in soils with or without residues, with multiple correlation coefficients 0.81 and standard error prediction 0.5‰ in soils with residues and 0.92 and 0.2‰ in soils without residues. The ratio performance deviation for the quantification of δ13C in soil was 2.5 in soil with residues and 3.8 without residues. This indicated that the model was adequate to determine the δ13C of unknown soils in the −16.2‰ to −20.4‰ range. The development of the NIR calibration permits analytic determinations of the values of δ13C in unknown agricultural soils in less time, employing a non-destructive method, by the application of the fibre optic probe of remote reflectance to the soil sample. 相似文献