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1.
β-CD-2-CTS was synthesized by β-cyclodextrin reacting with p-toluenesulfonyl chloride, then grafting with chitosan. The infrared spectra analysis and 13C NMR confirmed that β-cyclodextrin reacted with p-toluenesulfonyl chloride at the 2-position carbon atom in the substituted glucose unit of β-cyclodextrin and formed β-CD-2-OTs. In the 13C NMR of β-CD-2-OTs, the characteristic peak of the 2-postion carbon atom in the substituted glucose unit of β-cyclodextrin appeared at 78.43 ppm. β-CD-2-CTS was characterized with infrared spectra analysis and X-ray diffraction. In the infrared spectra of β-CD-2-CTS, the characteristic peak of α-pyanyl vibration of β-CD was at 848.6 cm−1. The characteristic peak of β-pyanyl vibration of CTS was at 894.9 cm−1. The X-ray diffraction analysis showed that the peak at 2θ = 20° decreased greatly in β-CD-2-CTS. The polymer inclusion complex of β-CD-2-CTS with iodine was prepared and its inclusion ability was studied. The experimental results showed that a nice bit of iodine was included with β-CD-2-CTS and formed a stable inclusion complex. After the subcutaneous implantation of the polymer inclusion complex of β-CD-2-CTS with 131I2 in rats, 131I2 exhibited the property of slow release. 131I2 in the blood of rats decreased slowly. 131I2 in the blood of rats maintained approximately half of maximum for 70 days later, and maintained much higher radioactivity in the organs of rats compared to the inclusion complex of β-CD with 131 I2, too. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2414–2421, 2001 相似文献
2.
The oxidative methylation of -, - and -picolines with methane to the corresponding vinyl- and ethylpyridines was carried out at 750°C and under normal atmospheric pressure, over sodium, cesium or sodium-cesium promoted magnesia catalysts. Among the three picolines, the -picoline was the most reactive, followed by - and -picolines. The (5 mol% Na-5 mol% Cs)/MgO catalyst provided higher yields than the individual promoters, at the same total alkali content of 10 mol%. 相似文献
3.
Hyun Jung Kim 《Journal of the American Oil Chemists' Society》2014,91(5):777-782
Despite the structural similarity of tocopherols, the antioxidative activities of tocotrienol homologues have not been studied often. In this study, the antioxidant activities of α-, β-, γ-, and δ-tocotrienols at various concentrations from 100 to 1,000 ppm in lard were evaluated. Headspace oxygen content of the lard without tocotrienol decreased from 21.1 to 10.7 % and the peroxide value increased from 0.4 to 33.4 mequiv/kg after 7 days of storage at 55 °C in the dark. α-Tocotrienol at 100 ppm and β-tocotrienol at 100 and 200 ppm effectively improved the oxidative stability of lard; however, the antioxidative activities of α- and β-tocotrienol reduced as the concentration increased to 1,000 ppm. The γ- and δ-tocotrienols improved the oxidation stability of lard and the effectiveness was essentially same at all concentrations (p > 0.05). The antioxidative activities of tocotrienols in the autoxidation of lard increased in the order of α-, β-, γ-, and δ-tocotrienols. The activities of tocotrienols in lard were different depending on the type of homologues and concentrations. 相似文献
4.
The aim of this study was to evaluate tissue distribution of vitamin E isoforms such as α- and γ-tocotrienol and γ-tocopherol
and interference with their tissue accumulation by α-tocopherol. Rats were fed a diet containing a tocotrienol mixture or
γ-tocopherol with or without α-tocopherol, or were administered by gavage an emulsion containing tocotrienol mixture or γ-tocopherol
with or without α-tocopherol. There were high levels of α-tocotrienol in the adipose tissue and adrenal gland, γ-tocotrienol
in the adipose tissue, and γ-tocopherol in the adrenal gland of rats fed tocotrienol mixture or γ-tocopherol for 7 weeks.
Dietary α-tocopherol decreased the α-tocotrienol and γ-tocopherol but not γ-tocotrienol concentrations in tissues. In the
oral administration study, both tocopherol and tocotrienol quickly accumulated in the adrenal gland; however, their accumulation
in adipose tissue was slow. In contrast to the dietary intake, α-tocopherol, which has the highest affinity for α-tocopherol
transfer protein (αTTP), inhibited uptake of γ-tocotrienol to tissues including adipose tissue after oral administration,
suggesting that the affinities of tocopherol and tocotrienol for αTTP in the liver were the critical determinants of their
uptake to peripheral tissues. Vitamin E deficiency for 4 weeks depleted tocopherol and tocotrienol stores in the liver but
not in adipose tissue. These results indicate that dietary vitamin E slowly accumulates in adipose tissue but the levels are
kept without degradation. The property of adipose tissue as vitamin E store causes adipose tissue-specific accumulation of
dietary tocotrienol. 相似文献
5.
The impacts of four different types of tocotrienol homologues on the singlet oxygen oxidation of lard were evaluated by measuring the headspace oxygen content and the peroxide value. Singlet oxygen oxidation of lard was induced by chlorophyll photosensitization. Samples of 0.100, 0.250, and 0.400 M lard in methylene chloride containing chlorophyll and α‐, β‐, γ‐, or δ‐tocotrienol were prepared and stored under light at 3,000 lux for 4 h. All tocotrienol homologues at 1.20 mM significantly prevented the singlet oxygen oxidation of lard. Chlorophyll under light produced singlet oxygen at 1.09 μmol oxygen/mL headspace/h. A steady state kinetic study showed that tocotrienols reduced the singlet oxygen oxidation of lard by quenching the singlet oxygen. Singlet oxygen reacted with lard at 6.50 × 104M?1 s?1. α‐, β‐, γ‐, and δ‐tocotrienol quenched singlet oxygen with the rate of 2.16, 1.99, 2.05, and 0.800 × 107M?1 s?1, respectively. Among them, α‐tocotrienol significantly prevented singlet oxygen oxidation of lard. 相似文献
6.
Serap Demir M. Vezir Kahraman Nil Bora Nilhan Kayaman Apohan Ayşe Ogan 《应用聚合物科学杂志》2008,109(2):1360-1368
A new β-cyclodextrin urethane-methacrylate monomer was synthesized from the reaction of toluene-2,4-diisocyanate, 2-hydroxyethyl methacrylate (HEMA), and β-cyclodextrin (β-CD). Based on inclusion character of β-CD, a series of hydrogels were prepared by irradiating the mixtures of β-cyclodextrin urethane-methacrylate monomer (β-CD-UM), poly(ethylene glycol) diacrylate (PEG-DA), HEMA, and the photoinitator. Gel percentages and equilibrium swelling ratios (%) of hydrogels were investigated. It was observed that the equilibrium-swelling ratio increased with increasing β-CD-UM content in the hydrogel composition. SEM images demonstrated that β-CD-UM based hydrogel have porous fractured surface. In this study four different drug molecules, salicylic acid, sulfathiazole, rifampicin, and methyl orange as model drug, which are capable of forming inclusion complexes withβ-CD were chosen. For sulfathiazole and rifampicin, the drug loadings are very low (0.04 and 0.008 mmol/g dry gel), whereas methyl orange and salicylic acid drug uptakes are found as 0.15 and 0.18 mmol/g dry gel, respectively. The incorporation of β-CD-UM comonomer into the gel slightly reduces the methyl orange and salicylic acid releases. However, a significant enhancement was achieved in the case of sulfathiazole delivery. It can be concluded that the inclusion complex formation capability of β-CD moiety increases the drug release by improving the aqueous solubility of hydrophobic drugs. On the other hand, in the case of hydrophilic drugs, the drug release retards by forming strong drug-β-CD complex and reducing the drug diffusivity. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
7.
8.
The effect of α-tocopherol (αTOH) (50–2000 ppm), γ-tocopherol (γTOH) (100–2000 ppm), and δ-tocopherol (δTOH) (100–2000 ppm)
on the formation and decomposition of hydroperoxides in purified fish oil triacylglycerols (TAG) was studied. The tests were
conducted at 30°C in the dark. Purified fish oil TAG oxidized very rapidly with no apparent induction period. The relative
ability of the tocopherols to retard the formation of hydroperoxides decreased in the order αTOH> γTOH>δTOH at a low level
of addition (100 ppm), but a reverse order of activity was found when the initial tocopherol concentration was 1000 ppm. This
dependence of relative antioxidant activity on tocopherol concentration was caused by the existence of concentrations for
maximal antioxidant activity for αTOH and for γTOH. An inversion of activity, on the basis of hydroperoxide formation, was
observed for αTOH at 100 ppm and for γTOH at 500 ppm, whereas the antioxidant activity of δTOH increased with level of addition
up to 1500–2000 ppm. None of the tocopherols displayed any prooxidant activity. All three tocopherols strongly retarded the
formation of volatile secondary oxidation products in a concentration-dependent manner. At concentrations above about 250
ppm there appeared to be a linear relationship between rate of consumption of αTOH and initial αTOH concentration, in accordance
with the linear relationship observed between the initial rate of formation of hydroperoxides and the initial αTOH concentration.
The rate of consumption of γTOH also increased with initial concentration, but to a lesser extent than for αTOH. At high levels
of addition the rate of consumption of δTOH was independent of initial concentration, appearing to reflect the greater stability
of this tocopherol homolog and participation in reactions with lipid peroxyl radicals only.
Presented in part at the AOCS annual meeting in San Diego, California, April 2000. 相似文献
9.
10.
Maret G. Traber Michalis Rallis Maurizio Podda Christine Weber Howard I. Maibach Lester Packer 《Lipids》1998,33(1):87-91
To evaluate skin penetration of various vitamin E homologs, a 5% solution of either α-tocopherol, α-tocotrienol, or γ-tocotrienol
in polyethylene glycol was topically applied to SKH-1 hairless mice. After 0.5, 1, 2, or 4 h (n=four per time point and four per vitamin E homolog), the skin was washed, the animals killed, the skin rapidlly removed,
frozen on dry ice, and a biopsy taken and sectioned: stratum corneum (two uppermost, 5-μm sections—SC1 and SC2), epidermis
(next two 10μm sections—E1 and E2), papillary dermis (next 100μ, PD), dermis (next 400 μm, D), and subcutaneous fat (next
100 μm, SF). SC1 contained the highest vitamin E concentrations per μ thickness. To compare the distribution of the various
vitamin E forms into the skin layers, the percentage of each form was expressed per its respective total. Most surprising
was that the largest fraction of skin vitamin E following topical application was found in the deeper subcutaneous layers—the
lowest layers, PD (40±15%) and D (36±15%), contained the major portion of the applied vitamin E forms. Although PD only represents
about 16% of the total skin thickness, it contains sebaceous glands—lipid secretory organs, and, thus, may account for the
vitamin E affinity for this layer. Hence, applied vitamin E penetrates rapidly through the skin, but the highest concentrations
are found in the uppermost 5 microns. 相似文献
11.
Gang Wang Tianyou Song Yong Fan Jianing Xu Miao Wang Liping Wang Lirong Zhang Li Wang 《Inorganic chemistry communications》2010,13(1):95-97
A novel lanthanide metal–organic framework, [Eu2(BDC)3(DMF)2]·(DMF)1.7(BDC = 1,3-benzenediacarboxylate) 1 has been synthesized under solvothermal condition and characterized by single-crystal X-ray structure determination, luminescent property, nitrogen gas adsorption, powder X-ray diffraction, IR, and TGA. 相似文献
12.
Water-soluble and water-insoluble β-cyclodextrin polymers (β-CDPs) were prepared from β-CD using 1,2,3,4-butanetetracarboxylic dianhydride (BTCA) as a cross-linker. The structures of the synthesized water-soluble and water-insoluble β-CDPs were characterized in detail using FT-IR, solution- and solid-state NMR, and 1H diffusion-ordered spectroscopic techniques. The water solubility of β-CDP was dependent on the reaction temperature as well as the initial feed ratio of β-CD and BTCA. The BTCA content and the ratio of BTCA molecules cross-linked and grafted to β-CD were also found to influence the water solubility of the polymers. Insoluble β-CDPs were effective in adsorbing bisphenol A (BPA) from aqueous media, with this absorption being highest in materials of low BTCA content, which corresponds to material of high β-CD content per unit mass of β-CDP. 相似文献
13.
Kiran Tiwari Rudramani Singh Vinai Kumar Singh Manoj Kumar Krishnamoorthi S. Kumar Krishna 《Iranian Polymer Journal》2020,29(7):615-623
Iranian Polymer Journal - In our recent work, we have reported on hydrogels devoid of cross-linkers. After observing the successful swelling and water retention properties, we have introduced... 相似文献
14.
Yehui Chen Liwen Yang Nianfa Yang Jingyi Yan Zhusheng Yang Jian Zhang 《Polymer Bulletin》2014,71(10):2507-2521
The synthesis and chiroptical properties of a novel optically active helical polymers, poly[(S)-6-acryloyl-2,2′-bisalkoxy-1,1′-binaphthyl] (poly-3), were reported. All the monomers readily underwent anionic polymerization to yield the polymers displaying optical rotations and Cotton effects in the UV–vis absorption region of side groups distinct to monomers (3) and the corresponding model compounds such as (S)-6-propionyl-2,2′-bisalkoxy-1,1′-binaphthyl (4) and (S)-6-heptanoyl-2,2′-bisalkoxy-1,1′-binaphthyl (5), implying the formation of main-chain chirality, most probable helicity. Their helical conformations were quite stable as revealed by the almost unchanged chiroptical properties measured at different temperatures. 相似文献
15.
《木材化学与工艺学杂志》2013,33(4):199-218
ABSTRACT Light-induced aging of lignocellulosic materials has been studied with a new technique involving selectively α-, β-, and γ-13C-enriched cell wall-dehydrogenation polymers (CW-DHPs) and solid state 13C NMR spectroscopy. The results from cross-polarization magic angle spinning (CP/MAS) 13C NMR experiments of unirradiated and irradiated CW-DHP have revealed mainly a decrease in the amount of end-groups of both coniferaldehyde and coniferyl alcohol type. The results suggest that these end-groups become saturated and that the terminal functionalites, i.e., γ-aldehyde and γ-hydroxymethyl groups, at least to some extent, are retained. The results indicate further that no detectable cleavage of the β-O-4 bonds occurs in the examined lignocellulosic model. In terms of proposed mechanisms of yellowing, there is marginal evidence that up to 2% of the α-labeled sites are converted by irradiation to α-carbonyls (aldehyde or ketones); moreover, we cannot dismiss the possibility that the precursor structures giving rise to these few α-carbonyls are β-O-4 structures. The 13C-enriched CW-DHP was formed directly on spruce (Picea abies) wood tissue (differentiating xylem) by administering selectively 13C-labeled coniferin at pH 6.0 in the presence of glucose oxidase and β-glucosidase, i.e., no phenol-oxidizing enzyme was added and the wood cells’ own enzymes polymerized the precursor. 相似文献
16.
17.
《Ceramics International》2020,46(9):13047-13053
Porous (Ba,Sr)(Co,Fe)O3-δ (BSCF) ceramics with high open porosity and good electrical conductivity was fabricated using Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF), which shows a high mixed ionic-electronic conductivity. In general, during the fabrication of porous ceramics by the sacrificial template method using pore former particles, closed pores are easily formed unless sufficient pore former particles are added. In this study, we have devised a method using the gelatinization-retrogradation phenomena of starch for producing a porous body with an excellent percolated pore network structure. By dispersing BSCF and starch in an aqueous slurry (0–50% by weight) and heating, gelatinization of the starch occurred and the starch particles adhered to each other. Furthermore, in order to retain the percolated structure, the water solvent was removed by freeze-drying without heating to obtain a dried green body. The sintering behavior of the porous BSCF bodies prepared under various conditions was characterized by microstructural observations and relative density measurements. By optimizing the process conditions of the gelatinization and retrogradation, a porous body having an open porosity of 48.3%, and with 99% of the total pores open, was obtained. The matrix was also well connected and showed a sufficiently high conductivity which was similar to the porous bodies made by the traditional sacrificial template method. 相似文献
18.
A new 1,6-diene, α-(2-phenylallyloxy)methylstyrene (1), was synthesized and its radical cyclopolymerizations were studied, since 1 is expected to yield highly cyclized polymers with thermal stability and high glass transition temperatures. A low homopolymerization tendency of the monofunctional counterpart of 1 can be assumed reasonably, because it is a derivative of α-methylstyrene with a low ceiling temperature. This means that intermolecular propagation leading to pendant unsaturations is hard to occur during the polymerization of 1, which results in the formation of highly cyclized polymers. In fact, the degree of cyclization of poly(1) obtained at 180 °C attained the value 99%. Structural studies using a monomeric cyclic compound obtained by the telomerization of 1 permitted to assign main repeating cyclic units of poly(1) to a six-membered ring. The poly(1)s with a higher degree of cyclization were found to be stable up to 300 °C on thermogravimetric analyses and their glass transition temperatures were detected at temperatures over 250 °C. 相似文献
19.
R. S. Bubnova S. N. Volkov V. A. Yukhno M. G. Krzhizhanovskaya 《Glass Physics and Chemistry》2016,42(4):349-358
Single crystals of the β-Ca3B2SiO8 new monoclinic modification have been obtained by cooling the melt of a stoichiometric composition. The crystal structure has been determined from the single crystal X-ray diffraction data and refined with R = 0.059 (wR = 0.069) in the monoclinic space group P21/m. The thermal behavior of the synthetic borosilicate has been studied. At 472 ± 5°С, a reversible phase transition of the first order occurs, leading to the formation of the orthorhombic α-Ca3B2SiO8 modification. The thermal expansion of α- and β-modifications of Ca3B2SiO8 is anisotropic: (α11 = 15, α22 = 16, α33 =–1, α V = 30 × 10–6°С–1) and α11 = 9, α22 = 28, α33 = 1, α V = 38 × 10–6°C–1, respectively. 相似文献
20.
T. B. Mikenas V. A. Zakharov V. E. Nikitin L. G. Echevskaya M. A. Matsko 《Catalysis in Industry》2011,3(2):122-127
Summarized results are presented from studying the formation of the active component of supported Ziegler type catalysts,
investigating the effect of the composition of these catalysts on the molecular mass characteristics of PE, and seeking new
methods for producing catalysts with optimum morphology. 相似文献