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1.
Francesco Michelangeli 《Journal of fluorescence》1991,1(3):203-206
A simple fluorimetric method is presented for measuring calcium uptake and inositol 1,4,5-trisphosphate (InsP3)-induced calcium release in microsomes using Fluo-3. This method is used to investigate the amplitude of calcium release (quantal release) induced by InsP3 from rat cerebellum microsomes. 相似文献
2.
Yan?Zhang Changchun?Wang Wuli?Yang Bin?Shi Shoukuan?FuEmail author 《Colloid and polymer science》2005,283(11):1246-1252
Biodegradable tri-component diblock copolymer was synthesized by bulk copolymerization of ε-caprolactone (CL) and D, L-lactide (LA) in the presence of methoxy poly(ethylene glycol) (MePEG), using stannous octoate as catalyst. Their chemical
structure and physical properties were investigated by GPC, NMR, DSC, TGAand XRD. The increase of CL/LA ratio in the diblock
copolymer leads to lower T
g, higher decomposition temperature and crystallinity. Nanoparticles formulated from MePEG–poly(CL-co-LA) (PCAE) possess spherical structure, which was characterized by dynamic light scattering (DLS) and transmission electron
microscopy (TEM). The DLS results indicate that the particle size increased with the increase of CL/LA ratio and the hydrophobic
fragment length in the copolymer. The drug encapsulation efficiency and the drug release behavior in vitro conditions of camptothecin
were measured by high performance liquid chromatography (HPLC). The encapsulation efficiency can be achieved as high as 84.4%
and the release behavior can be made well-controlled. MePEG–poly(CL-co-LA) nanoparticles might have a great potential as carriers for hydrophobic drugs. 相似文献
3.
Barbara Dogan Hans-Dieter Beckhaus Hermann Birkhofer Christoph Rüchardt 《欧洲无机化学杂志》1990,123(6):1365-1368
Effects of Substituents on the Strength of C - C Bonds, 81. - Heats of Formation and Strain of 1,1,2,2-Tetraethylethylene Glycol Dimethyl Ether and D,L .-1,2-Dimethyl-l,2-diphenylethylene Glycol Dimethyl Ether The heats of combustion of the title compounds 1 and 2 were measured calorimetrically with the result (kcal mol -1, s. d. in parentheses) ΔH°c = − 1880.1 (± 0.6) and − 2373.3 (± 1.4). The heat of vaporisation of 1 ΔHv = 14.3 (± 0.3) and the heat of sublimation of 2 ΔHsub = 27.2 (± 0.5) were derived from their temperature dependance of the vapor pressure. The latter were determined between 30 and 80°C using a flow method. The resulting standard heats of formation ΔH°t(g) = −122.4 (± 0.7) and −43.8 (±1.5) for 1 and 2 correspond to a strain enthalpy (s) of 15.9 and 8.0 kcal mol-1, respectively. The steric strain of the dimethoxyethanes 1 and 2 is about one fourth lower than the strain of the corresponding dimethylethanes 3 and 4 bearing the same substituents. Thus, a methoxy group causes less steric stress than a methyl group. 相似文献
4.
Enthalpies of dilution of aqueous systems containing formamide, dimethyl-formamide, the mixture of these amides, and each amide separately with mannitol, inositol, and cyclohexanol have been determined at 25°C. The data have been treated in terms of the Savage-Wood additivity principle and in combination with literature data. New values for the methylene-amide, carbinol-amide, and amide-amide group interaction enthalpies are presented. These may be used with data on a wider variety of solute systems to obtain interaction enthalpies for new groups. 相似文献
5.
富勒烯四甲氧基衍生物的合成与表征甘良兵,周胜,姜剑峰,黄春辉(北京大学化学与分子工程学院,北京,100871)武轶,吕木坚,潘景歧(北京微量化学研究所)(北京大学分析测试中心)关键词C_60衍生物,甲氧基,四氮杂环十二烷富勒烯化学是目前人们研究的热门... 相似文献
6.
A new tocopherol derivative, 7a‐methoxy‐α‐tocopherol ( 1 ), and a new taraxastane triterpene, taraxast‐1,20(30)‐dien‐3‐one ( 5 ), together with four known compounds, β‐tocopherol ( 2 ), α‐tocopherol ( 3 ), α‐tocospiro B ( 4 ) and taraxasterone ( 6 ) were isolated from the whole plant of Sida acuta. Their structures were elucidated by spectral analysis including MS, 1D and 2D‐NMR spectroscopy. Among those compounds, compounds 1 , 2 , and 3 showed significant antioxidant effect (EC50 = 86.9, 68.2, and 70.9 μM, respectively) in the DPPH radicals scavenging activity assay. 相似文献
7.
A highly rigid diamine monomer derived from naturally occurring myo‐inositol and its use for polyamide synthesis 下载免费PDF全文
Atsushi Sudo Shou Sugita 《Journal of polymer science. Part A, Polymer chemistry》2016,54(21):3436-3443
A rigid diamine was synthesized from myo‐inositol, a naturally occurring cyclic hexaol, and used as a monomer to synthesize polyamides. myo‐Inositol was treated with 1,1‐dimethoxycyclohexane to yield a bisketal bearing two hydroxyl groups, and from this bisketal, the target diamine was synthesized in three steps: (1) derivation of the diol into the corresponding bistriflate, (2) nucleophilic substitution of the bistriflate with sodium azide yielding a diazide, and (3) reduction of the diazide to the target diamine. The target diamine readily underwent polycondensation with dicarboxylic acid chloride in solution. The resulting polyamides, whose main chain inherited the rigid 5‐6‐5 system from the diamine monomers, have high glass transition temperatures. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3436–3443 相似文献
8.
Ce(IV) as ceric ammonium nitrate can effectively catalyze ring opening of epoxides with halides under very mild conditions and easy procedure to give the corresponding β-chloro-and β-bromohydrins in excellent yields. The reactions occur with both substituted and unsubstituted quaternary ammonium halides and with high regio- and stereoselectivity. The reaction of optically active styrene oxide with chloride ion was found to be highly stereospecific and afforded the corresponding β-halohydrin in 96% ee. 相似文献
9.
Partially bio‐based tri‐ and hexaallyl monomers: Synthesis from naturally occurring myo‐inositol and polyaddition with dithiols 下载免费PDF全文
Atsushi Sudo Yugo Shirakawa Tomio Sakue 《Journal of polymer science. Part A, Polymer chemistry》2017,55(9):1524-1529
myo‐Inositol, a naturally occurring cyclic hexaol, was converted to 2,4,6‐tri‐O‐allyl‐myo‐inositol and 1,2,3,4,5,6‐hexa‐O‐allyl‐myo‐inositol. Polyaddition of the former product, a tri(allyl ether) bearing three hydroxyl groups, with dithiols yielded the corresponding networked polymers. Their glass transition temperatures (Tgs) were higher than those of networked polymers formed by the polyaddition of 1,3,5‐tri‐O‐methyl‐2,4,6‐tri‐O‐allyl‐myo‐inositol. This implied the reinforcement of the networks by hydrogen bonding between the hydroxyl groups. Polyaddition of the latter product, a hexa(allyl ether), with dithiols yielded the corresponding networked polymers with much higher Tgs than those of all of the aforementioned networked polymers. This implied that efficient use of the hexafunctional monomer leads to the formation of more densely crosslinked polymers. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1524–1529 相似文献
10.
This work concentrates on extending the utilization of multiple dual mode (MDM) counter‐current chromatography in chiral separations. Two aromatic acids, 2‐(6‐methoxy‐2‐naphthyl)propionic acid (NAP) and 2‐phenylpropionic acid (2‐PPA), were enantioseparated by MDM counter‐current chromatography using hydroxypropyl‐β‐cyclodextrin (HP‐β‐CD) as chiral selector. The two‐phase solvent systems consisting of n‐hexane/ethyl acetate 0.1 mol/L phosphate buffer pH 2.67 containing 0.1 mol/L HP‐β‐CD (7.5:2.5:10 for NAP and 7:3:10 for 2‐PPA, v/v/v) were used. Conventional MDM and modified MDM were compared according to peak resolution under current separation mechanism. The influence of elution time after the first‐phase inversion and number of cycles for MDM were investigated. Peak resolution of NAP and 2‐PPA increased from 0.62 to 1.05 and 0.72 to 0.84, respectively, using optimized MDM conditions. Being an alternative elution method for counter‐current chromatography, MDM elution greatly improved peak resolution in chiral separations. 相似文献