Sorption of PAHs by aspen wood fibers as affected by chemical alterations

Sorption and desorption experiments for phenanthrene and pyrene, using untreated (UTR) and treated (bleaching and hydrolysis) aspen wood fibers, were examined to understand their sorption mechanisms. The wood was characterized by elemental and porosity analysis, solid-state 13C NMR, and diffuse reflectance infrared Fourier transform spectroscopy. Bleaching removed aromatic components, yielding the highest polarity and increased porosity, whereas hydrolysis removed a large percentage of hemicellulose and parts of amorphous cellulose, producing a matrix with more aromatic moieties, lower polarity, and higher porosity than that of the UTR wood fibers. All isotherms fitted well to the Freundlich equation and the N values had a decreasing trend from bleached (BL), UTR, low-temperature hydrolyzed to high-temperature hydrolyzed (HHY) wood fibers. BL fibers had the lowest sorption capacity (Koc) for both phenanthrene and pyrene. HHY had the highest Koc because of its high aromatic carbon content and low polarity. The results suggest that aromatic moieties and polarity of wood fibers play significant roles in polycyclic aromatic hydrocarbon (PAHs) sorption and desorption. Thus, both aromatic components and polarity should be considered when predicting the PAHs sorption/desorption by aspen wood fibers. This study demonstrated that aspen wood fibers are a potential sorbentfor PAHs and that chemical modifications of the wood matrix can effectively increase its sorption efficiency. These results may have implications for the treatment of stormwater runoff and other PAH-contaminated liquids.     

Adsorption and cosorption of tetracycline and copper(II) on montmorillonite as affected by solution pH

Land application of wastes generated from concentrated animal feeding operations may result in accumulation of tetracyclines (TCs) and metals in agricultural soils. Adsorption of TCs and metals on soil minerals strongly affects their mobility. This study was conducted to evaluate the interaction between tetracycline (TC) and Cu(ll) with regard to their adsorption and cosorption on montmorillonite as affected by solution pH. When solution pH was below 6.5, the presence of TC increased Cu(ll) adsorption on montmorillonite, which could be due to increasing Cu(II) adsorption via the TC bridge, or due to the stronger affinity of TC-Cu(II) complex to the mineral than Cu2+ ion itself. Zeta potential of the montmorillonite significantly decreased after the adsorption of TC, suggesting a strong interaction between TC and montmorillonite. Addition of Cu(ll) ions increased TC adsorption on the mineral in a wide range of pH. The experimental data were well fit with the weighted sum model. The complexes of TC and Cu(II) (CuH2L(2+), CuHL+, and CuL) had higher sorption coefficients (K(d)) than that of the corresponding TC species (H3L+, H2L, and HL-). Increasing adsorption of TC and Cu(II) on montmorillonite as they coexist in the normal pH environment may thus reduce their mobility.     

Leaching losses of nutrients and yield and nutrient uptake by container-grown begonia as affected by lime and fertiliser applications to a peat medium

The effect of increased lime applications and one rate of soluble basal fertiliser on leaching losses of NH₄-N, NO₃-N, P, Ca, Mg and K from peat in containers was studied in the presence or absence of Begonia semperflorens plants in a greenhouse pot experiment. Percentage recoveries (leached, plus extractable nutrient remaining in the peat, plus plant uptake) of mineral N and P were in the range of 60–80% while those for Ca, Mg and K ranged from 95 to 111%. Percentage leaching losses in the absence of plants were: mineral N, 75–76%; P, 59–74%; Ca, 5–7%; Mg, 14–19%; and K, 17–31%. In the presence of plants, the average decrease in the percentage loss of nutrients by leaching was: N, 9.3%; P, 4.4%; Ca, 0.5%; Mg, 0.3%; and K, 1.3% Liming tended to decrease leaching losses of NH₄-N, P, Ca and Mg but increase those of K and NO₃-N. The phosphate adsorption capacity of the peat was not measurable but significant ammonia fixation from added (NH₄)2SO₄ was demonstrated at high pH (>6.5) concomitant with high N rates (> 300 g N m^?3). Effective cation-exchange capacity (CEC) and CEC measured with unbuffered 1m NH₄CI were both more than doubled with increased lime additions as the pH of the peat increased from 4.3 to 5.6. The conventional CEC measurement (NH₄OAc, pH 7.0) and BaCl₂-TEA (pH 8.2) CEC both remained unaffected by the initial lime rates, and both greatly overestimated the CEC of the peat at its unbuffered pH.     

波尔多液的亚慢性毒性及其主要影响因素

波尔多液是生产中的常用农药,其在果蔬等食品中的残留可能会对食用安全造成不良影响。而波尔多液的主要活性成分为硫酸铜,其他成分有氧化钙等。为了评价波尔多液的亚慢性毒性并研究影响其亚慢性毒性的主要因素,通过SD大鼠30天喂养实验,分别以波尔多液和硫酸铜为受试物,观察大鼠生理状况,记录其体重和进食量,并对各组实验动物血液学指标、血液生化学指标以及脏器病理学指标进行了检测。结果表明,各组大鼠生长良好,生理状况正常,各项指标与对照组相比无明显异常。故波尔多液和硫酸铜无明显亚慢性毒性作用,波尔多液的最大无作用剂量超过50mg/kgBW,作为农药较为安全可靠。波尔多液主要成分硫酸铜最大无作用剂量超过125mg/kgBW,对波尔多液的亚慢性毒性无不良影响。     

Sorption of copper,zinc and cobalt by oat and oat products

We determined copper, zinc and cobalt sorption by oat and its products under variable pH conditions as well as the content of neutral dietary fiber (NDF) and its fractional composition. Adsorbents in a model sorption system were: oat, dehulled oat, oats bran and oats flakes. Three various buffers (pH 1.8, 6.6 and 8.7) were used as dispersing solutions. Results collected during this study indicate that copper, zinc and cobalt sorption is significantly affected by the type of cereal raw material. Zinc and copper ions are subjected to higher sorption than cobalt ions. Examined metal ions were subjected to high sorption under conditions corresponding to the duodenum environment (pH 8.7( regardless of the kind of adsorbent. A little lower sorption capacity is observed under conditions close to the neutral environment, while the lowest one is found in environment reflecting conditions of stomach juice (pH 1.8). Zinc ions are bound intensively by dehulled oat, while oats flakes bound mostly copper and cobalt, independently on environmental conditions. Contents of dietary fiber in oat, dehulled oat, oat bran and oat flakes were: 40.1, 19.3, 20.3 and 14.3%, respectively. The dominating fraction in all oat products was the fraction of hemicelluloses. The content of remaining fractions varies in dependence on the product.     

Sorption of copper,zinc and cobalt by oat and oat products

We determined copper, zinc and cobalt sorption by oat and its products under variable pH conditions as well as the content of neutral dietary fiber (NDF) and its fractional composition. Adsorbents in a model sorption system were: oat, dehulled oat, oats bran and oats flakes. Three various buffers (pH 1.8, 6.6 and 8.7) were used as dispersing solutions. Results collected during this study indicate that copper, zinc and cobalt sorption is significantly affected by the type of cereal raw material. Zinc and copper ions are subjected to higher sorption than cobalt ions. Examined metal ions were subjected to high sorption under conditions corresponding to the duodenum environment (pH 8.7), regardless of the kind of adsorbent. A little lower sorption capacity is observed under conditions close to the neutral environment, while the lowest one is found in environment reflecting conditions of stomach juice (pH 1.8). Zinc ions are bound intensively by dehulled oat, while oats flakes bound mostly copper and cobalt, independently on environmental conditions. Contents of dietary fiber in oat, dehulled oat, oat bran and oat flakes were: 40.1, 19.3, 20.3 and 14.3%, respectively. The dominating fraction in all oat products was the fraction of hemicelluloses. The content of remaining fractions varies in dependence on the product.     

Yield and flour quality of spring wheat as affected by soil tillage and animal manure

BACKGROUND: Yield and quality of organic bread wheat may be improved by adjusting tillage and type of manure. We tested two different tillage strategies (rotovation plus ploughing or ploughing only) before sowing spring wheat (Triticum aestivum L.) on a coarse loamy sand. The tillage strategies were combined with four nitrogen (N) rates of animal manure supplied in either slurry or liquid manure. RESULTS: Rotovation before ploughing had only a negligible influence on soil inorganic N content in the spring and on wheat biomass development. Liquid manure gave a higher protein and gluten content than slurry, probably due to its higher proportion of inorganic N. At low N rates, gluten from wheat supplied with slurry was softer than from wheat given liquid manure and responded differently to baking tests than expected from their gluten and protein content. At higher N rates, loaf volume corresponded well with the gluten and protein content. CONCLUSION: Soil tillage intensity did not have a major influence on soil N mineralisation patterns and manure N availability. Except at low N rates, the response of wheat flour to different types of animal manure is mainly determined by the amount of inorganic N supplied. Copyright © 2008 Society of Chemical Industry     

Sorption of copper (II) ions by pine sawdust

The sawdust of Calabrian pine was used as sorbent for the removal of Cu(II) ions from aqueous solution of copper sulfate pentahydrate (CuSO₄.5H₂O) at different concentrations, pHs and temperatures. The results showed that about 65–81% of Cu(II) ions in the solution could be adsorbed on the sawdust. The percentage of adsorped Cu(II) ions onto the sawdust increased with increasing initial concentration. Kinetic studies indicated that the sorption process followed the first order reversible kinetic model. It was also determined that the sorption process obeyed the Freundlich isotherm. Furthermore, the sorption thermodynamic was investigated in detail.     

阳离子染料对阴离子改性亚麻纤维的染色热力学研究

开发亚麻纤维的阳离子染料染色新工艺,以亚硫酸氢钠溶液对经高碘酸钠氧化处理的亚麻纤维进行阴离子改性,将改性后的亚麻纤维用阳离子染料进行染色.通过吸附等温线的绘制、染色饱和值和染色亲和力的计算,研究了改性亚麻纤维的染色热力学机理.结果表明:阳离子染料对阴离子改性亚麻纤维上染的吸附等温线与朗缪尔吸附等温线特征相符,佐证了具有磺酸基的改性亚麻纤维与阳离子染料之间发生了静电吸附,染色后的改性亚麻织物具有良好的匀染性、染色牢度和颜色鲜艳度,证明了阳离子染料对改性亚麻纤维染色的可行性.     

黄原胶对木薯阴阳离子淀粉糊性质的影响

本文采用Brabender黏度计和哈克流变仪研究了黄原胶对木薯阴、阳离子淀粉糊黏度、冻融稳定性及流变学性质的影响。结果表明:黄原胶使木薯阴、阳离子淀粉糊的峰值黏度和崩解值均显著增加,但其起始糊化温度有所降低;添加黄原胶后,阳离子淀粉的析水率有了一定程度的提高,冻融稳定性减弱,而阴离子淀粉的析水率下降;黄原胶的加入使两种变性淀粉凝胶的tanα值降低,储能模量(G’)增大,这使得木薯阴阳离子淀粉凝胶向趋于固性的方向发展。      

黄原胶对木薯阴阳离子淀粉糊性质的影响

本文采用Brabender黏度计和哈克流变仪研究了黄原胶对木薯阴、阳离子淀粉糊黏度、冻融稳定性及流变学性质的影响。结果表明:黄原胶使木薯阴、阳离子淀粉糊的峰值黏度和崩解值均显著增加,但其起始糊化温度有所降低;添加黄原胶后,阳离子淀粉的析水率有了一定程度的提高,冻融稳定性减弱,而阴离子淀粉的析水率下降;黄原胶的加入使两种变性淀粉凝胶的tanα值降低,储能模量(G')增大,这使得木薯阴阳离子淀粉凝胶向趋于固性的方向发展。     

Microbial transglutaminase-induced structural and rheological changes of cationic and anionic myofibrillar proteins

This study investigated the effects of microbial transglutaminase (TG) on structural changes in porcine myofibrillar protein (MP) under varying pH (2.0–6.0) and two ionic strength conditions (0.1 M versus 0.6 M NaCl). Lowering the pH below the isoelectric point (pI) of myosin induced protein unfolding as revealed by surface hydrophobicity and differential scanning calorimetry. Although the MP solubility at the low ionic strength (0.1 M NaCl) was maximal at pH 3.0, both SDS-PAGE profiles and dynamic rheology indicated TG could not cross-link MP under this condition. Based on the carboxyl group content, the TG-catalyzed deamidation was dominant at a pH lower than the pI of myosin (pH 5.0) while cross-linking occurred at higher pH. Moreover, deamidation had no effect on rheological properties of MP. The results indicate that the TG reaction was governed by the pH of substrate protein, and the reaction intensity was related to the solubility of protein.     

土壤后期供氮对烤烟产量和烟碱含量的影响

采用田间试验和土壤原位培养法在贵州的凤冈和金沙研究了土壤后期供氮对烤烟产量及品质的影响.结果表明,在相同的施氮量条件下,由于凤冈试验点土壤后期氮素矿化量远高于金沙试验点,在烟株生长的中后期(7～16周),前者的土壤氮素净矿化量(56kg/hm2)儿乎相当于后者(30kg/hm2)的2倍,造成前者烟叶的产量、产值远低于后者,但前者上部烟叶中的烟碱浓度远高于后者,且均超过了3.5%的适宜标准.凤冈试验点在移栽后5周土壤NH+4-N利NO-3-N已被大量消耗的情况下,烟株后期吸收的氮素主要来自于土壤氮素的矿化.后期土壤氮素矿化量对烟叶品质起着至关重要的作用.     

超声波-阴/阳离子表面活性剂协同提取茅岩莓总黄酮的工艺研究

优化超声波协同阴/阳离子表面活性剂提取茅岩莓总黄酮的工艺,通过单因素实验,考察表面活性剂浓度、阴/阳离子表面活性剂摩尔质量比、提取温度、乙醇浓度和提取时间对茅岩莓总黄酮得率的影响。在此基础上,固定阴/阳离子表面活性剂摩尔质量比为40∶1(SDS∶CTAB)、料液比1∶20(g/m L)和提取温度60℃,采用响应面实验考察表面活性剂浓度、乙醇浓度和提取时间对茅岩莓总黄酮得率的影响。结果表明最佳提取工艺参数为:表面活性剂浓度1.1%、乙醇浓度40%、提取时间57 min,此条件下茅岩莓总黄酮得率为23.27%,与预测理论值23.45%相差较小,说明该实验方法可行。     

含聚氧乙烯链季铵盐阳离子表面活性剂对阴离子染料染色的影响

选择了几种聚氧乙烯型季铵盐阳离子表面活性剂，探讨了这些表面活性剂与酸性染料的相互作用以及对染料染色性能的影响.结果表明，含聚氧乙烯链阳离子表面活性剂能降低酸性染料的初始上染速率，并具有较好的移染性，可开发为匀染剂.为新型表面活性剂的应用和新型染色助剂的开发提供了理论依据。     

超声波-阴/阳离子表面活性剂协同提取茅岩莓总黄酮的工艺研究

优化超声波协同阴/阳离子表面活性剂提取茅岩莓总黄酮的工艺,通过单因素实验,考察表面活性剂浓度、阴/阳离子表面活性剂摩尔质量比、提取温度、乙醇浓度和提取时间对茅岩莓总黄酮得率的影响。在此基础上,固定阴/阳离子表面活性剂摩尔质量比为40∶1(SDS∶CTAB)、料液比1∶20(g/m L)和提取温度60℃,采用响应面实验考察表面活性剂浓度、乙醇浓度和提取时间对茅岩莓总黄酮得率的影响。结果表明最佳提取工艺参数为:表面活性剂浓度1.1%、乙醇浓度40%、提取时间57 min,此条件下茅岩莓总黄酮得率为23.27%,与预测理论值23.45%相差较小,说明该实验方法可行。      

Characteristics of soybeans as affected by soaking conditions

The water absorption of soybeans in soaking is directly related to the changes in textural characteristics and grinding properties of soybeans for processing. In this study, we determined the characteristics of water absorption, solid loss, and moisture content, textural characteristics and grinding properties of soybeans at four different soaking temperatures, 10°C, 20°C, 30°C, and 40°C, and various soaking times up to 8 h. We found that the solid loss increased significantly when the soaking temperature increased from 30°C to 40°C. The measured moisture data of soaked soybeans fitted well with the data predicted using Peleg's equation. Rupture force and maximum tangent and secant modulus measured by the compression test decreased as the moisture increased, up to 122%. The grinding property of soaked soybeans was related only to the final moisture content and not to the soaking conditions. High soaking temperature could significantly reduce the required soaking time. Based on these results, we recommend that soybeans be soaked to minimal final moisture content of 120% before grinding.     

Interaction Between Sodium Chloride and Paracasein as Determined by Water Sorption

The model system, salt-paracasein-water, for binding interactions that influence ripening of salted cheeses was investigated. The amount of salt interacting with protein was calculated from water sorption data in the range 0.76-0.95 a_w for the system and for pure salt and protein. Calculations showed that the components did not behave independently in that the system behaved less like salt and more like paracasein than expected, evidencing interaction between salt and protein. The amount of interacting salt increased with added salt, decreasing a_w, moisture content during preparation and drying the system. At 0.85 a_w the amount of interacted salt was 0.08 g/g protein when the salt added was 0.30; the maximum interacted salt was about 0.11.     

利用红外分析方法测定阳离子型聚丙烯酰胺的阳离子度

常用的阳离子聚丙烯酰胺是由丙烯酰胺单体和阳离子单体共聚而成,其分子链上的阳离子基团在红外谱图中表现出特定的吸收,通过度量这些吸收峰的高度可以确定阳离子聚丙烯酰胺的阳离子度。     

颈部服装压对人体颈动脉窦生理的影响

为研究人体颈部服装压对颈动脉窦生理的影响,选取15名青年女性为实验对象,测量其穿着不同领宽的针织高领衫时的服装压值.通过台阶实验,对人体在静止-运动-静止过程中心率和血压的变化进行客观评价.研究认为:服装压与心率、血压存在相关性,各项生理指标在颈部受压超过1.2kPa时呈明显下降趋势,运动状态受压对心血管系统造成的负面...