水溶性纤维素

最近几年,中国的“富裕疾病”呈上升趋势,全国每年约有250万人死于心脑血管病、130万人死于肿瘤病,这不得不引起人们对饮食的高度警惕性。 青菜萝卜所以营养好,除了其营养素外,还有人类消化过程中所必需的重要物质——膳食纤维。膳食纤维包括非水溶性纤维素和水溶性纤维素。

第七册第8课——《鱼》

一、教学片断 师:这些鱼虽然大小、颜色不尽相同,但外形有着共同的特征。它们的外形有什么共同特征? 生:有头有尾。 生:身上有鳞片。 生:有嘴有眼睛。 生:鱼头尖,鱼尾扁的。 生:嘴不住地动。 生:身上长了好些“划水儿”

Effects of Gamma-Ray Irradiation on Dielectric Surface Breakdown of Polybutylene Naphthalate and Polybutylene Terephthalate Under Reduced Pressure

With the increasing application of electric and electronic devices in space and nuclear power stations, the polymeric insulation materials are inevitably exposed to various kinds of environments. Accordingly, it becomes necessary to investigate the effects of the radiation and air pressure on insulation materials. This paper describes the effects of gamma-ray irradiation and reduced pressure on dielectric breakdown of polybutylene naphthalate (PBN) and polybutylene terephthalate (PBT) by applying a DC pulse voltage. Both PBN and PBT were irradiated in air up to 100 kGy and then up to 1 000 kGy with a dose rate of 10 kGy/h by using a60Co gamma-source. The effects of total dose and reduced pressure on the time to dielectric breakdown and discharge quantity were discussed. Obtained results show that, while increasing the total dose, the discharge quantity decreased with PBN, but increased with PBT. With decreasing the air pressure, the discharge quantity increased with PBN, but decreased with PBT. With increasing the total dose, the time to dielectric breakdown increased with PBN, but decreased with PBT. With decreasing the air pressure, the time to dielectric breakdown increased with both PBN and PBT. The experimental results suggest that the chemical structure of polybutylene polymers plays a main role in the result of radiation reaction, which is related to cross-linking and degradation reaction.

Alkylation of p-Cresol with tert-Butanol Catalyzed by Novel Multiple-SO_3H Functioned Ionic Liquid

The alkylation of p-cresol with tert-butanol（TBA）to 2-tert-butyl-p-cresol（TBC）catalyzed by a novel multiple-SO3H functioned ionic liquid（IL1）was investigated.Meanwhile,the catalytic activity of this novel ionic liquid was compared with other four traditional ionic liquids.The results showed that IL1 has superior catalytic activity to other four traditional ionic liquids with the conversion of 85.3%and selectivity of 95.2%.Also,the reaction conditions were investigated to obtain the optimum conditions.Operational simplicity,small amount of usage,high activity,reusability and selectivity are the key features of this methodology.

Enantioselective Hydrogenation of Ethyl 2-Oxo-4-phenylbutyrate on Cinchona-Platinum Catalysts

Enantioselective hydrogenation of ethyl 2-oxo-4-phenylbutyrate to ethyl （R）-2-hydroxy-4-phenyl- bu- tyrate on Pt/γ-Al2O3 modified by 10,11-dihydrocinchonidine was studied by investigating the influences of the amount of modifier, initial concentration of reactant, pressure and temperature on conversion and enantiometric excess in a stirred autoclave and the effects of the liquid velocity, gas velocity, modifier concentration and various catalytic beds in a trickle-bed reactor. The maximum optical yields were about 50% and 60% in the two types of reactors, respectively. It was assumed that the total hydrogenation rate included the reaction rates over the unmodified and modified active sites on platinum surface and a kinetic model, which fitted the experimental data well in autoclave, was obtained. A simplified plug-flow model was proposed to describe the bed average efficiency of trickle-bed reactor.

Enantioselective extraction of clorprenaline enantiomers with hydrophilic selector of sulfobutylether-β-cyclodextrin by experiment and modeling

Enantioselective extraction of hydrophobic clorprenaline （CPE） enantiomers from organic phase to aqueous phases with sulfobutylether-β-cyclodextrin （SBE-β-CD） as the selector was investigated with insight into a number of important process variables, such as the type of organic solvent, concentration of selector, pH, and temperature. Equilibrium of the extraction system was modeled using a reactive extraction modcl with a homogeneous aqueous phase reaction. The important parameters of this model were determined experimentally. The physical distribution coefficients for molecular and ionic CPE were determined as 0.3 and 8.93, respectively. The equilibrium constants of the complexation reaction with SBE-β-CD were determined as 152 and 110 L/mol for R- and S-CPE, respectively. Results show that the experimental data agree with the model predictions perfectly. Comprehensively considering the experiment and model, the extraction conditions are optimized and the best extraction conditions are： pH of 6.0, SBE-β-CD concentration of 0.04 tool/L, and temperature of 5 ℃, providing the enantioselectivity （a） of 1.25, the fraction of R-CPE （φR） in aqueous phase of 0.71 and performance factor （pf） of 0.025.

Et_3NHCl-AlCl_3 Ionic Liquids as Catalyst for Alkylation of Toluene with 2-Chloro-2-methylpropane

Alkylation of toluene With 2-chloro-2-methylpropane （t-Bu-C1） to synthesize para-tert-butyltoluene （PTBT） was carded out in the presence of triethylamine hydrochloride-aluminum chloride ionic liquids used as the catalyst. The ionic liquids were prepared with different molar ratios of Et3NHC1 to A1CI3, and the effect of the molar ratio between A1C13 and Et3NHC1, the reaction time, the reaction temperature, the ionic liquid dosage, as well as the molar ratio of toluene to chloro- 2-methylpropane on the alkylation reaction of toluene with chloro-2-methyl-propane was investigated. The test results showed that the acidic ionic liquids prepared with Et3NHC1 and A1C13 had good activity and selectivity for the alkylation reaction of toluene with alkyl chloride to produce PTBT. The optimal reaction conditions were specified at an A1C13 to Et3N- HCI ratio of 1.6, a reaction temperature of 20 ℃, a mass fraction of toluene to ionic liquid of 10%, and a chloro-2-methyl- propane to toluene molar ratio of 0.5. Under the suitable reaction conditions, a 98% conversion of chloro-2-methylpropane and an 82.5% selectivity of PTBT were obtained. Ionic liquids could be reused 5 times with its catalytic activity unchanged, and the regenerated ionic liquids can be recycled.

Antiphotooxidative Effect of Ascorbic Acid Microemulsion in Virgin Coconut Oil

This study was intended to determine the effectiveness of ascorbic acid microemulsion for inhibiting photooxidation of virgin coconut oil （VCO）. The ascorbic acid microemulsion was prepared by mixing ascorbic acid, deionized water, surfactant mixture, and VCO as continuous phase. Ascorbic acid microemulsion at 50, 100, 150, 200, or 250 ppm was dispersed into VCO. The same level of ascorbyl palmitate, TBHQ （tertiary butylhydroquinone）, and BHA （butylated hidroxyanisole） were added into VCO and used for comparison. All of these samples were subsequently subjected to photooxidation under fluorescent light exposure （4,000 lux） for up to 8 hours at room temperature （30 ~ 1 ~C）. Peroxide values and p-anisidine values of photooxidized samples were measured at 1 hour interval. The result indicated that at the level of 250 ppm, ascorbic acid which was included into the microemulsion system effectively inhibited photooxidation of VCO in comparison with the other antioxidants. This study confirmed that a highly hydrophilic singlet oxygen quencher （SOQ） such as ascorbic acid can be successfully incorporated into the microemulsion system and the addition of ascorbic acid microemulsion effectively inhibited photooxidation of VCO during storage under fluorescent light.

Alkylpolyglycoside inducing poly (butylene terephthalate) non-woven graft copolymerization of chitosan

In order to improve the wettability and biocompatibility of the poly （butylene terephthalate） non-woven （PBTNW）, the method of surface modification is used to graft copolymerization of chitosan （CS） onto the PBTNW under alkylpolyglycoside （APG） inducing. The product is thoroughly characterized with the Fourier transform infrared spectroscopy （FrIR）, the electron spectroscopy for chemical analysis （ESCA）, the thermogravimetric （TG） and the scanning electron microscopy （SEM）. It is found that chitosan is successfully grafted onto PBTNW. In addition, the water contact angles, hemolysis tests and cytotoxicity evaluation tests show an improvement in wettability and biocompatihility as a result of graft copolymerization of chitosan. So the CS-grafted PBTNW exhibits greater superiority than the original PBTNW. The CS-grafted PBTNW can be a candidate for blood filter materials and other medical applications.

Nonisothermal Crystallization Kinetics of Poly(butylene adipate-co-terephthalate) Copolyester

Nonisothermal crystallization behavior of poly(butylene adipate-co-terephthalate)(PBAT) synthesized via direct esterification and polycondensation reactions was investigated by the differential scanning calorimetry(DSC).The Avrami equation modified by Jeziorny and the Z.S.Mo equation were employed to describe the non-isothermal crystallization kinetics of copolyester samples.The test results showed that the Avrami equation was successful in describing nonisothermal crystallization process of PBAT copolyesters.PBAT copolyester could give birth to secondary crystallization.The crystallization parameter(Zc) increased with an increasing cooling rate and the Avrami exponent(n) was around 2.3.For a given cooling rate,the value of Zc demonstrated a sagging trend with an increase in adipic acid(AA) content.The equation proposed by Z.S.Mo was successful in describing the nonisothermal crystallization kinetics of PBAT copolyesters.

Preparation and Properties of a New Type of Poly(butylene-terephthalate)with Layered Silicate Nanocomposites

In this paper, poly(butylene-terephthalate)-layered silicate of clay nanocomposites (NPBT) are reported. Their thermal properties, heat distortion temperature (HDT) and crystallization nucleation are investigated. NPBT samples have apparent viscosity over 0.85, HDT of 30℃ to 50℃ higher than that of poly (butylene-terephthalate) (PBT) for clay load from 1.0% to 10.0% (by mass), and higher capability to accommodate clay than other polymers. The nonisothermal crystallization experiments indicate that the better thermal degradation behavior and crystallization rate of NPBT are 50% higher than PBT, and its injection mould processing temperature is lowered from 110℃ to 55℃. NPBT samples are characterized by several techniques. X-ray shows an original clay interlayer distance enlarged from 1.0 nm to 2.5 nm, while both TBM and AFM indicate an average size from 30nm to lOOnm of exfoliated clay layers, and 3%(by mass) of particle agglomeration being phase separated from PBT matrix, which are factors on some mechanical properties decrease of NPBT. The disappearance of spherulitic morphology in NPBT resulted from layers nucleation is detected. Improving NPBT properties by treating clay with long chain organic reagent and controlling the way to load it is suggested.

Preparation and Characterization of Silica Modified with Calix[4]arene Derivatives

Three new silica gel modified with calix[4]arene derivatives （p-tert-butyl-calix[4]arene （PC4）, calix[4]arene （C4） and calix[4]arene sulfonate （C4S）） have been prepared via modification of activated silica gel with toluene 2,4-di-iso-cyanate （TDI） as linker in tow step. The modified silica were characterized by fourier transform infrared spectroscopy （FT1R）, thermal analysis （TGA） and elemental analysis. The FTIR spectra and TGA analysis verified that the calix[4]arene derivates are covalent attached to the silica. Scanning electron microscope SEM and Brunauer-Emmett-Teller BET analysis have been done to get information about the sample＇s surface shape and area. SEM and BET analysis reveal that the modified silica are in the range of microporous adsorbent.

Synthesis of Oligohydroxynapthylenes and Their Use in Making of Heat-Stable and Electro-Conducting Rubbers

By oxidative polycondensation of 1-naphthol and their copolycondensation with aniline or p-phenylenediamine the polyfucntional polyconjugated oligomers consisting of hydroxynaphthylene links have been prepared. These soluble and meltable oligomers showing thermostability, semiconducting and paramagnetic properties and also high reactivity at reactions characteristic for aromatic hydroxyl groups were used as active filler at preparation of rubbers from butyl and butadiene-nitrile rubbers. It has been shown that in partial or full substitution of carbon black by oligohydroxynaphthylenes or cooligohydroxynaphthylenephenylamines in composition of vulcanizate the prepared rubbers are characterized by noticeably high heat-physical, physical-mechanical and electrical properties （Pv = 10^8 - 10^6Om. cm ）.

Synthesis and Crystal Structure of ( Z)-4-( p- Bromophenylthio)-3-( p-nitrobenzoyloxy)-3-buten-2-one

A new enone (CH 3CO C( p NO 2C 6H 4COO)=CH S C 6H 4( p Br) 5, C 17 H 12 NBrO 5S, M r =422.25) was synthesized and its crystal structure was determined by X ray diffraction method. The crystal belongs to the monoclinic system, space group P2 1/c with a=6.4121(9), b=12.804(1), c=20.998(2) , β=94.884(9)°, V=1717.1(3) 3, Z=4, D c =1.633 g/cm 3, μ (Mo Kα )=2.542 mm -1 , F( 000)=848. Final R =0.0428 and wR =0.0916 for 3335 reflections with I>2σ(I) . The title compound exists as Z isomer with p bromothiophenolate and o nitrobenzoate groups cis arranged around asymmetrical centre. This observation suggests that the substitution of thiophenolate for bromine is a stereoselective step.

Photolysis and Rate Constant of 2,3-butanedione with OH Radicals in the Aqueous Phase under Tropospheric Conditions

Photolysis rate （J1） and reaction rate constants （kl） for the biacetyl （butane-2,3-dione） were evaluated in aqueous phase using a continuous photolysis system with a conventional Xe-Hg arc lamp as a light source. The OH radicals was generated by H2OE/UV process and biacetyl （CH3C（O）C（O）CH3） concentrations were monitored using 2,4-DNPH derivatization method. 2,3-butanedione molecule is widely present in the atmosphere, it have been detected in hydrometeors （fogs, rain, and clouds） and at a significant yield （up to 10μmolar）. The measurements were performed at 294 K and with free pH values. Our results lead to the following obtained values： J1= 3×10^-4 S^-1 and k1 = （6.17±0.95）×10^8 M^-1·s^-1.The uncertainty listed above is ±15%.

Synthesis and Crystal Structure ofDinitratedioxobis(p-methyl Phenyl Butyl Sulfoxide)Uranium(Ⅵ)[UO_2(p-CH_3C_6H_4SOC_4H_9)_2(NO_3)_2]

The title compound [UO2 （p-CH3C6H4SOC4H9）2 （NO3 ）2] is triclinicwith space group P1. a=8. 651 （3）, b=9. 097（2）, c=9. 621 （2） A;a=92. 29（1）, β=95. 97（3）, r=98. 25（3）, V=744. 1（3） A3, Z=1, Mr=786.41, Dc=1. 425 g/cm3. u=5. 626 mm-1, F （000） =300. R=0. 030, Rw=0. 071 for 2917 reflectionswith I≥2（I）. Uranyl ion is coordinated to six oxygen atoms, of which two are fromtwo monodenate sulfoxides and the others from two nitrate groups. The coordinationPOlyhedron around U is a hexagonal bipyramid, the U atom is in the center of symmetry.

Study on Structure and Crystallinity of A New Biodegradable Aliphatic-Aromatic Copolyester

A series of biodegradable aliphatic-aromatic copolyesters, poly(butylene terephthalate-co-butylene adipate-co- ethylene terephthalate-co-ethylene adipate) (PBATE), were synthesized from terephthalic acid (PTA), adipic acid (AA), 1,4-butanediol (BG) and ethylene glycol (EG) through direct esterification and polycondensation. The sequence structure and crystallinity of the copolyester were investigated by 1H NMR spectroscopy and the wide-angle X-ray diffractometry (WAXD). The analytical results showed that the PBATE copolyester was a random copolymer and the composition of PBATE copolyester was almost consistent with the feed molar ratios. The crystal structure of PBATE copolyester belonged to the triclinic crystalline system; The variation in melting point of the synthesized PBATE copolyester agreed well with the estimation obtained by the Flory equation and was applicable to the random copolymer.

Upregulation of Nrf2-regulated gene expression by tBHQ alleviates cyclophosphamide-induced hematotoxicity in mice

Hematological toxicity （bone marrow suppression） is the most common dose-limiting adverse effect of chemotherapies. The nuclear factor erythroid 2-related factor 2 （Nrf2） is a pivotal coordinator of cellular defensive responses against chemical insults in many tissues including bone marrow. In the present study, the effects of tert-butylhydroquinone （tBHQ） on the expression of Nrf2-regulated genes in peripheral blood cells and cyclophosphamide （CTX）-induced hematotoxicity in mice were investigated. CTX induced apoptosis of peripheral blood nucleated cells and leukopenia in mice, accompanied by mobilization of bone marrow hematopoietic cells, tBHQ treatment induced the expression of Nrf2-regulated genes such as heine oxygenase 1 （HO1） and glutamate-cysteine ligase catalytic subtmit （GCLC） in RAW264.7 mouse macrophage cells and peripheral blood cells both in vitro and in vivo. Interestingly, pretreatment with tBHQ alleviated CTX-induced mouse peripheral blood cell apoptosis and leukopenia in vivo, indicating possible involvement of Nrf2 in the protection against CTX-induced hematotoxicity. This study provides new information on the chemotherapy-induced hematotoxicity, and suggests Nrf2 could serve as a target for the development of chemoprotectants against hematotoxicity.

绒坝岔姑娘

1993年的夏天,我在四川甘孜县的一位藏族大妈家做客。一位身着黑色藏袍的妇女不停地为我们掺茶。并不时地对着我诡秘地笑笑,看样子她像有三十几岁了。大妈告诉我,她是一位远房的亲戚,住在绒坝岔——距北十多公里外的一个乡上。 我记起四年前曾经去过那里。 喝过了茶,大妈一家盛装让我照像。

Chemometrics-assisted excitation-emission fluorescence spectroscopy for simultaneous determination of ethoxyquin and tert-butylhydroquinone in biological fluid samples

A novel method applying simple, rapid, effective and inexpensive excitation-emission matrix （EEM） fluorescence spectroscopy coupled with second-order calibration method for simultaneous determination of ethoxyquin （EQ） and tert-butylhydroquinone （TBHQ） contents in biological fluid samples was developed. After a simple data preprocessing that was to insert zeros below the first-order Rayleigh scattering, the second-order calibration method based on the alternating normalization-weighed error （ANWE） algorithm was used to deal with EEM data. Via the introduced ＂second-order advantage＂, the individual con- centrations of the analytes of interest could be obtained even in the presence of uncalibrated interferences. The experimental concentration ranges for the analytes were as follows： EQ, from 4.58 to 20.6 p.g mL-1 in plasma and from 6.87 to 20.6 gg mL-1 in urine; TBHQ, from 4.49 to 20.2 ~tg mL-1 in plasma and from 6.73 to 22.4 I.tg mL-l in urine. The recoveries from spiked bi- ological fluid samples were in the ranges of 92.8%-106.2% for EQ and 94.6%-107.2% for TBHQ. These results demonstrate that the three-dimensional EEM fluorescence with second-order calibration method is a powerful tool for obtaining both EQ and TBHQ quantitative results in plasma and urine samples, and could be applied to more complex matrices.