聚合物/水混合体系中水的状态和性质的研究

阐述了聚合物/水混合物中水的状态和性质。关于亲水聚合物水溶液中水的状态,目前存在两种模型,间断模型和连续模型。间断模型根据与聚合物相互作用力的强弱,认为混合体系中存在自由水,冷冻键合水和非冷冻键合水。连续模型则认为体系中存在一种状态范围的水,它是介于与聚合物强相互作用的水和不受聚合物影响的水之间的一种连续的状态。介绍了混合体系中水产生反常性质的原因。由于亲水性聚合物材料的广泛应用,有必要对聚合物水溶液体系中不同状态水的含量与性质有更深入的了解。     

Analysis of bioactive ingredients in the brown alga Fucus vesiculosus by capillary electrophoresis and neutron activation analysis

Two different types of bioactive components of the seaweed Fucus vesiculosus were analysed: (1) polyphenols (phlorotannins) by capillary electrophoresis (CE) and (2) mineral part (including bioactive microelements) by neutron activation analysis (NAA). CE experiments were carried out using a UV detector (at 210 nm) and an uncoated silica capillary. The best separation was achieved at a voltage of 20 kV using borate or acetate buffer in a methanol/acetonitrile mixture as background electrolyte. The CE analysis data were confirmed by high-performance liquid chromatography (HPLC). Determination of mineral composition of algal biomass by NAA was performed on the basis of various nuclides; the best results (from 38 elements determined) were obtained for Mn, Fe, Zn, As, Br, Sr, I, Ba, Au and Hg.     

高效液相色谱法测定海洋水体与沉积物中光合色素

建立了海洋水体与沉积物中30种光合色素的反相高效液相色谱检测方法。海水滤膜和沉积物分别采用95%甲醇和95%丙酮超声萃取。萃取液混合一定比例的超纯水后,采用Eclipse XDB C8反相柱进行分离,以乙腈(A)、甲醇(B)和四丁基羟胺-甲醇(C)混合液为流动相进行洗脱,检测波长为430,440和450nm,柱温为50℃。色谱分离梯度为:0min,100%C;22min,25%A,45%B和30%C;28～38min,70%A,20%B和10%C;38.1～40min,100%C。对23种已知浓度色素的线性关系、检出限和加标回收率进行分析。结果表明,相关系数范围为0.9972～0.9998,检出限范围为0.0305～0.7740ng,加标回收率范围为88.6%～103.3%。     

共振光散射法测定环境水样中痕量铅(Ⅱ)

用简易荧光计研究了在微酸性介质中,铅（Ⅱ）-碘化钾-十六烷基三甲基溴化铵体系的共振散射光谱,考查了它们的光谱特征,影响因素和适宜的反应条件;确定了散射光强度与溶液中Pb（Ⅱ）质量浓度的关系,提出了共振光散射法测定Pb（Ⅱ）的方法.该法在室温下进行,操作方便,具有较高的灵敏度;线性范围为1.0～40.0 ng/mL,方法的检出限为0.74 ng/mL;用于环境水样中Pb（Ⅱ）含量的测定,结果满意.     

不同分子量壳聚糖和壳聚糖硫酸酯的抗氧化活性

不同分子量壳聚糖和壳聚糖硫酸酯的抗氧化活性;壳聚糖;壳聚糖硫酸酯;超氧阴离子自由基（ ）;羟自由基（·OH）;抗氧化活性     

Phragmites australis (Reed) as an Efficient,Eco-Friendly Adsorbent for Brackish Water Pre-Treatment in Reverse Osmosis: A Kinetic Study

A cost-effective adsorbent was prepared by carbonization of pre-treated Phragmites australis reed at 500 °C. Phragmites australis was characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Brunauer–Emmett–Teller (BET) surface analyses. XRD of the as-prepared adsorbent exhibited a partially crystalline structure with a specific surface area of 211.6 m²/g and an average pore diameter of 4.2 nm. The biosorption potential of novel biosorbent Phragmites australis reed was investigated with a batch scale and continuous flow study. The study was conducted at different constraints to obtain optimum pH conditions, adsorbent dose, contact time, agitation speed, and initial TDS concentration. In order to analyze the properties of the procedure and determine the amount of sodium removal, Langmuir, Freundlich, and Dubinin–Radushkevich isotherms were tested. The optimal values of contact time, pH, and adsorbent dose were found to be 150 min, 4, and 10 g/L, respectively, with an agitation speed of 300 rpm at room temperature (27 °C). The three tested isotherms show that the adsorption of Na⁺ onto the prepared adsorbent is a hybrid process from physi- and chemisorption. For industrial application, the adsorbent was tested using the adsorbent column technique. Pseudo-first-order, pseudo-second-order, and diffusion models were connected, and it was discovered that the information fit best to the pseudo-second-arrange active model. According to the intraparticle diffusion model, the mechanism goes through four stages before reaching equilibrium. The periodicity test shows that the adsorption ability of Phragmites australis can be recovered by washing with 0.1 M HCl.     

Structure and Synthesis of (±)-Caudoxirene,a New Spermatozoid-Releasing and -Attracting Pheromone from the Marine Brown Alga Perithalia caudata (Phaeophyceae,Sporochnales). Part V

Cis-3-(trans-1,2-Epoxybut-3-enyl)-4-vinylcyclopentene ((±)- 4 , caudoxirene) is a new gamete-releasing and gamete-attracting pheromone from the marine brown alga Perithalia caudata (Sporochnales). The key step of its synthesis is the diastereoselective alkylation of the aldehyde 8 with the [(phenylthio)allyl]titanium reagent 9 to yield the erythro-β-hydroxy sulfide 10 which affords 4 on sequential treatment with Me₃O·BF₄ and aq. NaOH. The lowest effective concentration of (±)- 4 for gamete-release is found at 1.4 × 10^?11 mol/l seawater.     

Increased Antioxidant Activity and Changes in Phenolic Profile of Kalanchoe pinnata (Lamarck) Persoon (Crassulaceae) Specimens Grown Under Supplemental Blue Light

Antioxidant compounds protect plants against oxidative stress caused by environmental conditions. Different light qualities, such as UV‐A radiation and blue light, have shown positive effects on the production of phenols in plants. Kalanchoe pinnata (Lamarck) Persoon (Crassulaceae) is used for treating wounds and inflammations. Some of these beneficial effects are attributed to the antioxidant activity of plant components. We investigated the effects of blue light and UV‐A radiation supplementation on the total phenol content, antioxidant activity and chromatographic profile of aqueous extracts from leaves of K. pinnata. Monoclonal plants were grown under white light, white plus blue light and white plus UV‐A radiation. Supplemental blue light improved the antioxidant activity and changed the phenolic profile of the extracts. Analysis by HPLC of supplemental blue‐light plant extracts revealed a higher proportion of the major flavonoid quercetin 3‐O‐α‐l ‐arabinopyranosyl (1→2) α‐l ‐rhamnopyranoside, as well as the presence of a wide variety of other phenolic substances. These findings may explain the higher antioxidant activity observed for this extract. Blue light is proposed as a supplemental light source in the cultivation of K. pinnata, to improve its antioxidant activity.     

Effect of Visible Light on the Dimerization of Cobalt (II) Tetrasulfonated Phthalocyanine in Water

Abstract

Beelen and coworkers in the Netherlands recently reported that visible light enhanced the rate of selective oxidation of mercaptoethanol by dioxygen, catalyzed by cobalt (II) tetrasulfonated phthalocyanine (CoTSPC). The Dutch workers speculated that visible light promoted disaggregation of CoTSPC, producing more of the catalytically active monomer.

If Beelen and associates are correct, then it is possible that the values for the dimerization constants of CoTSPC are in error. since the values were measured spectrophotometrically in the region of the spectrum where Beelen contends visible light promtes disaggregation. To test whether the dimerization constants are altered by the spectrophotometer, the absorbance of a CoTSPC solution was measured with a diode array UV-VIS spectrophotometer. By comparing the spectrum of CoTSPC in the UV region with the tungsten lamp active and then inactive, one can see whether the visible light affects aggregation. It turned out that no change was observed in the spectrum of CoTSPC when the tungsten lamp was turned off, so the dimerization constants measured in the visible region of the spectrum are not affected by the spectrophotometer.     

Photoinhibition of photosynthesis in Macrocystis pyrifera (Phaeophyceae), Chondrus crispus (Rhodophyceae) and Ulva lactuca (Chlorophyceae) in outdoor culture systems

The effect of solar radiation on photosynthesis and chlorophyll fluorescence associated to photosystem II (PS II) was determined in the Phaeophyta Macrocystis pyrifera, the Rhodophyta Chondrus crispus and the Chlorophyta Ulva lactuca by oxygen evolution and pulse-amplitude-modulated (PAM) fluorescence. The algae were maintained in 1.2 m3 outdoor tanks with constant aeration and at 8, 26 and 100% incident irradiance (E(o)). All three species showed a decrease in deltaF/F'm values during solar noon compared to values in the morning and afternoon, suggesting a photoinhibition of photosynthesis. In general, photoinhibition was negatively correlated to increasing daily irradiance in all three species. Photoinhibition in C. crispus occurred in tissue incubated at 8, 26 and 100% E(o), while in M. pyrifera and U. lactuca a decrease in deltaF/F'm values was only observed in tissue incubated at 100% E(o). This suggests that species that naturally grow at greater depths might be more susceptible to excessive light when cultured in shallow waters compared to species that naturally inhabit shallower depths. In M. pyrifera, deltaF/F'm values were lower in the afternoon than those in the morning, suggesting slower repair mechanisms of the photosystem II compared to the other species. The results suggest that photoinhibition could be reduced by reducing incident irradiance to culture systems or increasing of biomass to promote self-shading. Gross oxygenic photosynthesis increased linearly at low electron transport rates after which it saturated in all three species. This suggests that chlorophyll fluorescence could be used as an indicator of the physiological status of macroalgae maintained in dense aquaculture systems.     

CaCl2在甘氨酸+水和丙氨酸+水混合溶剂中的活度系数

利用离子选择性电极(ISE)测定了298.15 K时CaCl2在甘氨酸+水和丙氨酸+水混合溶剂中的活度系数. CaCl2的质量摩尔浓度变化范围为0.01～0.20 mol/kg, 氨基酸的质量摩尔浓度变化范围为0.10～0.40 mol/kg. 用Debye-Hückel扩展方程和Pitzer方程进行理论计算得到的活度系数基本一致. 依据McMillan-Mayer理论, 计算了CaCl2从纯水到氨基酸水溶液的标准转移Gibbs自由能, 利用最小二乘法拟合求得了对相互作用参数(gEA)和盐效应常数(ks). 讨论了这两种氨基酸的加入对CaCl2的活度系数、热力学稳定性及盐效应常数的影响.     

Micelle Formation and Counterion Binding of Dodecylammonium Alkanesulfonates in Water at Different Temperatures

A temperature study was performed on micelle formation of a series of homologous cationic surfactants having organic counterions (alkanesulfonates) with carbon numbers ranging from 1 to 4: dodecylammonium salts of methanesulfonate (DAMS), ethanesulfonate (DAES), propanesulfonate (DAPS), and butanesulfonate (DABS) in water. The critical micelle concentrations (CMCs) and the degree of counterion binding (β) were determined at different temperatures ranging from 5 to 50°C by means of conventional electric conductance measurements. From the temperature dependence of β as well as CMC, Gibbs energy ΔG⁰_m, enthalpy ΔH⁰_m, and entropy ΔS⁰_m, on micelle formation, were estimated for the respective surfactants. As for the temperature dependence of CMC for these surfactants, the temperature-CMC curves have a minimum around 30°C and show that the CMC at each temperature is lowered by about 3 mmol dm^-3 per methylene group in the alkyl chain of the counterions. The relationship between β and temperature suggested that the counterion of MS^- behaves most similarly to common univalent ions such as halide ions. In contrast, PS^- and BS^-, having a stronger ability to lower CMC and to promote association of surfactant ions with counterions as well as of surfactant ions themselves, behave more like those of surfactant ions, and ES^- shows the most complicated character between those of common univalent ions and organic ions. However, the temperature dependence of enthalpy change, ΔH⁰_m demonstrates that these four surfactants are divided into two groups: (1) DAMS and DAES and (2) DAPS and DABS. In addition, the entropy change ΔS⁰_m as a function of alkyl chain length gives evidence that the contribution of the entropy term to the Gibbs energy on micelle formation clearly separates between DAES (m = 2) and DAPS (m = 3). A similar discontinuity is found even in the plot of ΔG⁰_m versus carbon atom number of alkyl chain, m, and in the plot of ΔG⁰_m versus estimated hydrodynamic radius of counterions. All the results obtained have indicated that lengthening the alkyl chains initially hinders micelle formation, but the longer chains are markedly effective in lowering the CMC and probably in increasing the aggregation number, owing to enhanced hydrophobic interaction between counterion and the micellar surface and/or core.     

稀土Eu3+对不同光强下红叶石楠色素含量及PAL活性的影响

以盆栽红叶石楠(Photinia fraseri)优良品种'红罗宾'二年生组培苗植株为供试材料,探讨了不同遮光条件及稀土元素Eu3+处理对其顶部叶片色素含量、苯丙氨酸解氨酶(PAL)活性和Ca2+-ATPase酶活性的影响.结果显示,减少光照强度会导致叶绿素和类胡萝卜素含量上升,而使花青苷、红色素和PAL活性下降;稀土元素Eu3+处理一定程度提高了花青苷含量和PAL及Ca2+-ATPase酶活性.通过Eu3+和钙离子螯合剂(EGTA)、钙离子载体(A23187)、钙通道阻断剂(Verapamil)及钙调蛋白拮抗剂(CPZ)组合处理对50%光强下红叶石楠顶部叶片PAL活性影响的研究,推测Eu3+的生理作用机制可能是Eu3+通过细胞膜上的钙离子转运系统进入细胞内部,取代Ca2+-CaM信号系统中的Ca2+形成Eu3+ -CaM和(或)Eu3+-Ca2+-CaM复合物,替代Ca2+启动钙信号系统激活靶酶,调节效应酶功能,进而调控植物的一系列生理生化过程.     

Different addition modes of cyclopentadiene and furan at methylidene(thio)hydantoins

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不同介质条件下纳米二氧化钛溶胶的低温制备及其光催化性能表征

以四氯化钛为原料,分别以硝酸和过氧化氢为介质在低温下制备了两种二氧化钛溶胶A和B,通过X-射线衍射、透射电子显微镜、紫外-可见吸收光谱等测试手段进行了表征。结果表明,两种样品中的TiO2结晶相颗粒均呈锐钛矿型结构,样品A呈球形,粒径为4.8nm,样品B呈纺锤形,粒径为11．2nm;样品B比A结晶度高,而且光吸收波长红移了大约130nm。通过室外光催化降解亚甲基兰和室内光催化降解品红两组实验对比,研究了样品A和B的光催化活性,结果表明样品B比A具有更高的光催化性能。     

Activity of Water and Osmotic Coefficients of Histidine Derivatives in Aqueous Solutions at 310.15 K

From the data of vapor pressure osmometry the activity of water, osmotic coefficients, and the values of activity coefficients of two derivatives of histidine: N-Boc-L-histidine (Boc-His-OH, m=0.005–0.14 mol⋅kg⁻¹) and N-Boc-L-histidine-methyl ether (Boc-His-OMe, m=0.005–0.05 mol⋅kg⁻¹) are obtained in aqueous solutions at 310.15 K. From the comparison of water activity and osmotic coefficient values it follows that Boc-His-OMe shows a more pronounced deviation from ideality than Boc-His-OH. Both components exhibit a stronger non-ideality than histidine and a weaker one than His⋅HCl. By means of potentiometric titration the acid-base properties of Boc-His-OMe are investigated and the ionization constant at 298.15 K is determined. The pK value related to the acid-base equilibrium of the nitrogen atom in the imido group of the imidazole ring is higher (6.47) than the corresponding value of histidine (6.00).