不同来源黄腐酸性质,性能的研究

用相同的方法从风化煤,草炭,生化黄腐酸发酵料中提取黄腐酸,性质,性能测试结果是：生化黄腐酸分子量小,含氧功能团多,抗絮凝作用强,与微量营养元素铬（螯）合能力强,进入植物细胞快,在农业上效果明显,风化煤黄腐酸相对分子量大,含氧功能团少,抗絮凝作用低,草炭黄腐酸性质,性能在两者之间又更靠近生化黄腐酸。     

腐植酸类物质凝聚及沉淀特性的研究

通过对不同产地，不同提取方法获得的煤炭腐植酸和经过生物发酵人工合成的生化黄腐酸分别进行铝离子絮凝实验和酸化沉淀实验，发现煤炭腐植酸、腐植酸盐、棕惰酸、黄腐酸都同时具有被铝离子定量絮凝和在酸性条件下定量沉淀的特性，这类物质具有极其相近的化学特性。生化黄腐酸在上述两方面显示出与煤炭腐植酸十分不同的特性。     

煤炭黄腐酸和生化黄腐酸界定研究

煤炭黄腐酸和生化黄腐酸已经在国内外得到广泛推广应用,但对二者的界定和检测一直没有统一的认识和方法,这直接影响了生产应用和检测分析。为此,作者对不同产地、不同工艺的煤炭黄腐酸和生化黄腐酸,做了不同酸浓度絮凝沉淀试验和分析检测．并参考国内外有关试验情况,提出了对煤炭黄腐酸和生化黄腐酸新的界定方法和创新理论。     

电解质对黄腐酸溶液的絮凝机理探讨

通过一价盐,二价盐对黄腐酸溶液的絮凝值与溶液浓度间的不同的变化规律,提出了两种不同的盐对黄腐酸的不同絮凝机理。     

硫酸铝对黄腐酸絮凝作用的研究

本文通过对标准黄腐酸主要官能团的分析测定及标准黄腐酸硫酸铝絮凝物中铝离子含量的分析,实验结果表明在絮凝过程中Al^3 与黄腐酸的交联型式可以近似得认为是1：1型式;铝离子与黄腐酸的主要官能团之间并没有明确的化学计量关系。     

铝离子对黄腐酸絮凝效果的研究

本文采用正交实验研究了铝离子与黄腐酸的絮凝效果，考虑的影响因素有反应温度、pH值、絮凝时间及絮凝剂硫酸铝的量。结果表明：温度100℃，pH值为5～6，絮凝1．5h，20％的硫酸铝3．5mL为较好的絮凝条件。     

肥料中腐植酸测定的研究

通过对腐植酸、泥炭、腐植酸盐、黄腐酸、生化黄腐酸、腐植酸类肥料等腐植酸产品中腐植酸含量多种测定方法的比较研究认为，“酸析碱溶容量法”虽然可以克服重量法和容量法的缺陷，但不适合于黄腐酸类产品的测定；容量法是测定肥料中腐植酸含量较适合的方法；黄腐酸与生化黄腐酸可以通过在一定温、湿度条件下是否产生霉菌来判别。     

生化黄腐酸的界定及其资源开发利用探讨

用生物技术方法是否可以从植物残体中制取黄腐酸?生化黄腐酸是否存在?它的化学特征和作用机理如何理解?笔者对生物或化学方法制取类似腐植酸的物质已研究多年,本文将阐述生物发酵制取类黄腐酸物质(生化黄腐酸)的界定及其资源开发利用的一些看法。     

利用生物技术开发生化黄腐酸新肥源

煤腐植酸(Humic Acid，简称HA)和煤黄腐酸(Fulvic Acid，简称FA)在我国80年代就开始在农牧和医药方面广泛应用，并取得了较好效果。90年代利用生物技术开发的(非煤资源)类黄腐酸物质，即生化腐植酸(Biochemical Humic Acid，简称BHA)和生化黄腐酸(Biochemical Fulvic Acid，简称BFA)在农、牧、医等领域得到了广泛应用并取得了一定成效。本世纪初，利用生化技术相继开发的类似HA或FA的物质，较早期利用纯微生物发酵生产的BFA又有重大改进和突破，实现了生化肥源开发和产业化同步发展，从而获得了稳定和高效优质的类腐植酸或黄腐酸新肥源。     

生化黄腐酸对堆肥中氰化物及重金属的影响

正为了明确生化黄腐酸对堆肥过程中氰化物降解及重金属形态变化的影响,以木薯渣、干鸡粪为原料,设置了T1(堆肥原料+1‰生化黄腐酸)、T2(堆肥原料+2‰生化黄腐酸)、T3(堆肥原料+3‰生化黄腐酸)和CK(不添加生化黄腐酸的堆肥原料)4个处理,测定不同堆肥处理中氰化物的含量变化和     

Significance of Coprophagy for the Fatty Acid Profile in Body Tissues of Rabbits Fed Different Diets

Four groups of eight New Zealand hybrid rabbits were fattened with ad libitum access to the following pelleted experimental diets: ryegrass meal or alfalfa meal fed either alone or with oats meal in a ratio of 1:1. After 25 weeks they were slaughtered and dissected. Fatty acid (FA) profiles of caecotrophs (re-ingested fermentation products of the caecum), perirenal adipose tissue and intramuscular fat in the Musculus quadriceps were determined. With high proportions of branched-chain FA (BFA) and trans FA, and increased proportions of saturated FA relative to the diets, the caecotroph FA profile showed a clear fingerprint of anaerobe microbial lipid metabolism including biohydrogenation. By contrast, the FA profiles of adipose and lean tissue comprised high proportions of polyunsaturated FA (PUFA), whilst BFA and trans FA occurred in much lower proportions compared to the caecotrophs. Thus, coprophagy did not substantially modify the FA composition of the tissues investigated. Use of forage-only diets, compared to the oats supplemented diets, led to extraordinary high proportions of n-3 PUFA (including 18:3 and long-chain n-3) in the fat of adipose (21.3 vs. 6.7%) and lean tissue (15.4 vs. 5.7%). The forage type diet (grass vs. alfalfa) had smaller effects on the FA profiles. Indications of diet effects on endogenous desaturation, chain elongation and differential distribution of functional FA between the two tissues investigated were found.     

Synthesis of amphiphilic block copolymers based on poly(dimethylsiloxane) via fragmentation chain transfer (RAFT) polymerization

Dihydroxy terminated poly(dimethyl siloxane) (PDMS) was modified to form a di(trithiocarbonate) functional molecule capable of forming tri-block copolymers via the reversible-addition-fragmentation chain transfer (RAFT) process. Two statistical copolymer blocks were grown from the central PDMS block, comprising units of N,N-dimethyl acrylamide (DMA) and 2-(N-butyl perfluorooctanefluorosulfonamido) ethyl acrylate (BFA), to form A-B-A triblock macromolecules. The molecular weight of these block copolymers were found to increase with conversion while the polydispersity of the molecular weight distribution remains under 1.25. An unusual and interesting kinetic phenomenon was observed in that the copolymerization behaviour of DMA and BFA was influenced by the initial PDMS block. We surmise that this might be a direct observation of a ‘bootstrap’ effect.     

H2O2预氧化对BFA复合融雪剂性能的影响及其融雪机理

针对H₂O₂预氧化对生化黄腐酸（BFA）钙盐复合物的融雪化冰性能影响及其机理进行了研究。结果表明,在H₂O₂与BFA质量比为1.5、pH 7.5、35℃的最佳预降解条件下反应120 min,可使BFA钙盐复合物的冰点降低27%。紫外光谱、红外光谱及凝胶色谱分析结果表明,BFA经H₂O₂氧化降解后,一些复杂的芳香族有机物发生降解甚至开环、不饱和脂肪烃被氧化,产生了大量小分子羧酸、醇、酚及烯烃等有机物。它们在Ca²⁺的络合作用下形成了小分子聚合物或共聚物,在融雪化冰中起主要作用。增加BFA结构中的-COOH、-OH和ph-OH等亲水性基团含量是提高BFA钙盐复合融雪剂性能的关键。     

Coagent assisted polypropylene radical functionalization: monomer grafting modulation and molecular weight conservation

The occurrence of significant degradation by β-scission reaction is a severe drawback affecting the classical procedure of polypropylene (PP) functionalization in the melt with maleic anhydride (MAH) or derivatives and free radical initiators. The present work deals with the control of the PP blocks degradation by using a specially designed furan derivative, butyl 3-(2-furyl) propenoate (BFA), as coagent able to control the PP blocks scission during PP functionalization process. More specifically MAH or BFA were used as functionalizing reagents for a propylene/ethylene 77/23 mol% semi-block copolymer (PPC) either separately or as mixture (MAH/BFA) with different molar ratios. The PPC functionalized samples were then characterized by determining the number of grafted groups (functionalization degree FD) and the molecular weight (MW). Finally, the effect of the feed conditions on the process and on functionalized PPC properties are discussed by hypothesizing a reaction mechanism, which takes into account all the occurring parallel reactions.     

Effects of soil nitrogen level on ferulic acid inhibition of cucumber leaf expansion

It has been suggested that the allelopathic activity of phenolic acids should be primarily important in soils of low fertility. If this is true, then plant growth inhibition by phenolic acids may be unimportant in managed agricultural soils. The objective of this study was to determine how soil nitrogen (N) level might modify phenolic acid inhibition of growth. Cucumber seedlings (Cucumis sativus cv Early Green Cluster) grown in containers in growth chambers under varying N levels (5, 10, 15, 20, and 25 g N/g soil) in Portsmouth B,-horizon soil material were treated with ferulic acid (0 or 10 g/g soil). Nitrogen and ferulic acid (FA) were applied every other day to the soil surface. The amount of FA in the soil solution declined with depth in the containers. A more rapid disappearance of FA from the soil solution was observed for the last FA treatment (0% recovered after 10 hr on day 23) than the first treatment (44% recovered after 10 hr on day 13). Both low N (5 g N/g soil) and FA treatments reduced shoot dry weight, the mean absolute (AGR) and the mean relative (RGR) rates of leaf expansion, and increased the root-shoot ratio. High N treatments reduced shoot dry weight and the AGR. Ferulic acid inhibited cucumber seedling growth over a range of N concentrations, suggesting that the allelopathic activity of phenolic acids may be important in both nutrient limiting and nonlimiting soils for some species.Paper No. 12219 of the journal series of the North Carolina Agricultural Research Service, Raleigh, North Carolina 27695-7601. The use of tradenames in this publication does not imply endorsement by the North Carolina Agricultural Research Service of products named, nor criticism of similar ones not mentioned.     

Microbial Resistance Mechanisms to the Antibiotic and Phytotoxin Fusaric Acid

Fusaric acid (FA) produced by Fusarium oxysporum plays an important role in disease development in plants, including cotton. This non-specific toxin also has antibiotic effects on microorganisms. Thus, one expects a potential pool of diverse detoxification mechanisms of FA in nature. Bacteria and fungi from soils infested with Fusarium and from laboratory sources were evaluated for their ability to grow in the presence of FA and to alter the structure of FA into less toxic compounds. None of the bacterial strains were able to chemically modify FA. Highly FA-resistant strains were found only in Gram-negative bacteria, mainly in the genus of Pseudomonas. The FA resistance of the Gram-negative bacteria was positively correlated with the number of predicted genes for FA efflux pumps present in the genome. Phylogenetic analysis of predicted FA resistance proteins (FUSC, an inner membrane transporter component of the efflux pump) revealed that FUSC proteins having high sequence identities with the functionally characterized FA resistance protein FusC or Fdt might be the major contributors of FA resistance. In contrast, most fungi converted FA to less toxic compounds regardless of the level of FA resistance they exhibited. Five derivatives were detected, and the detoxification of FA involved either oxidative reactions on the butyl side chain or reductive reactions on the carboxylic acid group. The production of these metabolites from widely different phyla indicates that resistance to FA by altering its structure is highly conserved. A few FA resistant saprophytic or biocontrol strains of fungi were incapable of altering FA, indicating a possible involvement of efflux transporters. Deployment of both efflux and derivatization mechanisms may be a common feature of fungal FA resistance.     

Phenolic Thermoset Matrix Reinforced with Sugar Cane Bagasse Fibers: Attempt to Develop a New Fiber Surface Chemical Modification Involving Formation of Quinones Followed by Reaction with Furfuryl Alcohol

Summary: A new chemical modification of sugar cane bagasse fibers for phenolic thermoset composites is presented. It consists in creating quinones in the lignin portions of fiber and react them with furfuryl alcohol to create a coating around the fiber more compatible with the phenolic resins used to prepare polymeric matrix. Sodium periodate was used in suitable conditions to oxidize mainly phenolic syringyl and guaiacyl units of the lignin polymer to create quinones, which were characterized by UV‐visible diffuse reflectance spectroscopy by comparison with model compounds. The reactivity of furfuryl alcohol (FA) with fibers was greatly enhanced after they were oxidized: 13% weight percent gain compared to 2% without oxidation. Chemical analysis of unmodified and FA‐modified fibers have shown an important degradation of hemicelluloses and a slight one of cellulose which almost maintains its crystallinity. A 25% decrease of strength and length properties of the fibers after FA chemical treatment was measured by dynamic mechanical analysis. The lignin‐like proportion of the fiber was greatly enhanced after the FA‐treatment. This was confirmed by thermal analysis, DSC, and TGA experiments, on unmodified and FA‐modified fibers. SEM analysis of the fibers and of phenolic composites with modified fibers have confirmed the FA grafting and shown a better compatibility at the interface between the chemically modified fibers and the phenolic matrix. Nevertheless, the chemical treatment of the fibers decreased the impact strength of the composite, which could be caused by the fiber damage suffered during the chemical modification and for the more intense adhesion at the interface, which in some cases decrease somewhat the impact strength.

Cross photomicrography of FA‐modified sugar cane bagasse fiber (600×).     

生化黄腐酸与其他来源黄腐酸组成性质的初步比较

通过引用有关文献数据,对生化黄腐酸（BFA）与其他来源黄腐酸的化学组成、结构和性质进行了对比研究,推断BFA是一种富含糖苷配键、羟基、甲氧基和氨基的低芳香度水溶性脂肪酸,似属新生态腐植酸类范畴。建议对BFA进行系统的分析检测,以期推动BFA的基础研究、标准制定和推广应用。     

One-pot synthesis of fatty acid epoxides from triacylglycerols using enzymes present in oat seeds

In our previous work we used ground oat (Avena sativa) seeds as an inexpensive source of enzymes for the modification of FA or their chemical derivatives. We have extended this work by observing the products derived from an intact fat and three vegetable oils through the concerted action of oat seed enzymes. A modified reversed-phase HPLC protocol was devised that allowed the quantification of FFA, epoxy FA, and acylglycerols without derivatization. It was found that the addition of the surfactant deoxycholate or calcium chloride was needed to observe best hydrolysis of TAG to FA. Without an added oxidant, lipase action produced up to 80% by weight of FA at pH 7–9 with small amounts of DAG and MAG. When the oxidant t-butyl hydroperoxide was added in the presence of deoxycholate, the FA were partially converted to epoxide derivatives (up to 35% by weight). When calcium chloride replaced deoxycholate, only 4% by weight of the product was epoxide derivatives. The highest levels of FA epoxides were generated at pH7, and up to 15% by weight of the product at this pH was epoxymonostearin (monoepoxyoctadecanoylglycerol). The optimal molar amount of t-butyl hydroperoxide to add with deoxycholate for high epoxide formation was 1.4 to 2.8 times the amount of fatty esters in soybean oil. In no instance were oxidized DAG or TAG detected, demonstrating that a highly specific enzymatic process was responsible for epoxide formation. The epoxide products may be used to produce polyols with high viscosity for grease preparations.