Ready chemical conversion of acid hydrolysis lignin into water-soluble lignosulfonate III: Successive treatment of acid hydrolysis lignin and a lignin model compound by phenolation and arylsulfonation*

The chemical conversion of red pine sulfuric acid lignin (Klason lignin) (SAL) as an acid hydrolysis lignin sample to water-soluble arylsulfonates of lignin derivation (i.e., phenolized SAL) was investigated. Treatment of phenolized SAL with chlorosulfonic acid followed by alkali hydrolysis gave water-soluble sulfonated products with a sulfonic acid group on their aromatic nuclei quantitatively. The products possess 2.0 SO₃Na/C₉ C₆. In contrast, the content of sulfuric acid group in sulfonated SAL was only 0.33C₉. Chlorosulfonation of 1-guaiacyl-l-p-hydroxyphenylethane as a phenolized guaiacyl lignin model compound revealed that the sulfonyl chloride group was introduced at thepara position of an aromatic methoxyl group, theortho position of a phenolic hydroxyl group, or both.     

Effect of ectomycorrhizae on the growth and uptake and transport of 15N-labeled compounds by Pinus tabulaeformis seedlings under water-stressed conditions

 Seedlings of Chinese pine (Pinus tabulaeformis Carr.) were grown in a growth chamber using a sterilized soil/sand/vermiculite mixture, and were inoculated with the ectomycorrhizal fungus Cenococcum graniforme (Sow.) Ferd. and Winge. The function of external mycelium of ectomycorrhiza for uptake and transport of N from ¹⁵N-labeled NH₄ ⁺ and NO₃ ^– for plant nutrition was evaluated under well-watered conditions and water stress. The pots comprised two-compartments, whereby the penetration of roots was prevented by a nylon mesh bag which the mycorrhizal hyphae were allowed to pass in order to colonize the rest of the pot. ¹⁵N-labeled NH₄ ⁺ or NO₃ ^– was applied to the area of the pot to which the root had no access. At harvest, the ¹⁵NH₄ ⁺ concentration in plant tissues was significantly promoted by the formation of mycorrhizae both under well-watered conditions and water stress. The ¹⁵NO₃ ^– concentration was reduced by water stress and increased by mycorrhizal formation. The enhancement of ¹⁵NO₃ ^– uptake caused by mycorrhizal formation was more evident under water stress than under well-watered conditions. The external mycelia of the ectomycorrhizae took up and transported NH₄ ⁺ and NO₃ ^– from the soil to the plant, thereby improving plant nutrition and growth, in addition to helping the plants to avoid the effects of water stress. Received: 31 October 1997     

道路匝道的坐标计算方法

本文利用道路中线中曲线组成形式.通过数学推证。给出了匝道坐标的计算方法.推导出了计算公式.并通过实例进行了验证.证明此种计算方法实用可行。     

Initial soil development in lignite ash landfills and settling ponds in Saxony‐Anhalt,Germany

Weathering and initial soil formation was investigated on 5 sites of lignite ash disposal differing in age (5 to 30 years) and methods of disposal (landfills and sluicing to settling ponds). Soils developed on lignite ash derived substrates were characterized by low bulk densities (< 0.85 g cm^—3), high contents of gypsum (maximum 27%) and calcium carbonate (maximum 46%), high pH values (7—9), very high contents of organic carbon (about 20%), and high contents of ammonium oxalate soluble Si, Al, and Fe containing compounds. These features depended on the constitution of the lignite and the burning conditions. As the substrates were initially in disequilibrium with their environmental surroundings, they were subjected to rapid weathering. Typical features were the depletion of gypsum and decarbonatization in the topsoils of the profiles. Furthermore, pedogenic organic carbon became enriched by ruderal vegetation despite low contents of plant available P and K and high pH values. The C : N ratios increased with profile depth, which indicated the input of pedogenic OM with low C : N ratios into topsoils and the predominance of lignite with a wide C : N ratio (> 100) in subsoils.     

梯形异质结Bi2O3/BiOI的制备及降解四环素的机制研究

以绿色焙烧方法制备梯形异质结复合材料Bi_2O_3/BiOI,将复合材料Bi_2O_3/BiOI用于抗生素生产废水中四环素的降解,并与纯的Bi_2O_3与BiOI的降解效果进行对比。以X射线衍射(XRD)、X射线光电子能谱(XPS)对Bi_2O_3/BiOI样品物相组成和形貌进行表征分析,采用分光光度法测试并计算Bi_2O_3/BiOI样品降解四环素,结果显示:降解率为92.4%,一级动力学常数为0.018 59 min~(-1)。密度泛函理论计算显示,Bi_2O_3与BiOI的功函数分别为3.0、6.0 eV。梯形异质结复合材料Bi_2O_3/BiOI在光催化反应时,在内建电场和能带弯曲的共同作用下,BiOI中导带上还原能力较弱的电子将与Bi_2O_3价带中氧化能力较弱的空穴部分复合,从而保留较强还原以及氧化能力的光生电子和空穴,这可能是梯形异质结复合材料Bi_2O_3/BiOI具有较高光催化活性的原因。     

挥发性风味物质在碳水化合物中释放与保留的研究进展

风味的优劣逐渐成为食品能否得到消费者青睐的重要参考指标。碳水化合物作为食品主要营养成分之一,已被发现其对食品中挥发性风味化合物的保留与释放会产生显著的影响。本文综述了碳水化合物与风味化合物的作用方式,并分别从碳水化合物、风味化合物2种角度对挥发性风味物质在碳水化合物基质中释放与保留的影响因素进行了阐述,以期为风味物质在碳水化合物基质中的可控释放提供科学依据和参考。     

The role of açaí (Euterpe oleracea Mart. 1824) as a chemoprotective agent in the evaluation of antioxidant defence,oxidative damage and histology of juvenile shrimp Litopenaeus vannamei (BOONE, 1931) exposed to ammonia

This study investigated the effects of the use of the inclusion of açaí on the diet of shrimp Litopenaeus vannamei on antioxidant and histopathological responses after exposure to ammonia. The shrimps were fed two experimental diets: control and with 10% of açaí inclusion (W/W), for 35 days. Afterwards, the organisms were exposed at four concentrations of ammonia (0.01‐control; 0.26; 0.48 and 0.91 mg NH₃‐N L^?1) for 96 hr. The total antioxidant capacity (ACAP) of the gills decreased significantly in both diets when exposed to ammonia, whereas in the muscle, the açaí promoted an increase in ACAP. Concomitantly, lipid peroxidation levels increased in the gills and decreased in muscle. After exposure to ammonia, glutathione‐S‐transferase activity increased in hepatopancreas in shrimps fed with açaí facilitating the detoxification of lipid peroxidation by‐products, and the concentration of protein sulfhydryl groups decreased in the gills and muscle of the shrimp of the control diet, evidencing protein damage, an unobserved response in shrimps that received the açaí diet. Histopathological changes decreased in açaí‐fed shrimps about the control diet after exposure to ammonia. It is concluded that açaí mitigated ammonia‐induced histopathological changes, improved the antioxidant defence system (gills and muscle) and attenuated the lipid damage in the muscle.     

茶叶有效成分对黑色素形成的抑制作用

黑色素是一种高分子生物色素,皮肤的颜色由黑色素的合成类型、累积量、黑素小体的再分布及降解决定.太阳紫外线辐射是导致黑色素形成过多的最常见因素.黑色素虽能保护皮肤细胞免受紫外线损伤,但异常积累将会导致黑色素紊乱疾病的发生.因此开发绿色、安全、高效的植物来源的黑色素抑制剂成为近年来研究的热点.不少研究表明茶叶提取复合物或茶...     

Influence of mineral fertilizers and different soil types on nutrient leaching: Results of lysimeter studies in East Germany

A lysimeter experiment on mineral fertilizer use and soil type was begun in 1985 to study the interrelationships between the level of mineral fertilization and the leaching of nutrients. Increased application of mineral fertilizers brought about not only a significant reduction in effluence build-up, but also a significant increase in yield. The lowest levels of nitrogen leaching were found in clay-sand soil in use as grassland, and the highest in sandy soil used as arable land. Unexpectedly, the study was unable to prove statistically that a reduction in N, P and K leaching follows automatically from a reduction in mineral fertilization. Hence, suboptimal fertilization cannot be the only corrective measure if a noticeable or marked reduction in the adverse impact on water quality due to nutrient leaching is to be achieved. Interim plantings should be integrated in crop rotations. Agricultural crops must be siteadapted and suited to the fertilization regime.     

不同品种猪IFN-α基因的克隆与序列分析

根据现有猪α干扰素(IFN-α)基因序列设计引物,应用PCR技术直接从肝组织基因组中扩增丹系长白和法系长白、英系大白和法系大白猪IFN-α基因。将克隆得到的特异性片段克隆入pGEM-TEasy载体中,转化感受态细胞JM109,运用蓝白斑筛选、质粒PCR鉴定及酶切鉴定筛选阳性可疑菌株,并将筛选的阳性株进行测序。结果表明,得到了上述4个品系的猪IFN-α基因。核苷酸同源性均在97.2%以上,氨基酸同源性均在92.8%以上。