嘧菌酯/聚丙烯腈微球的制备及缓释性能

采用聚丙烯腈(PAN)为原料，通过静电喷雾技术制备了载有嘧菌酯的PAN微球。研究了工作电压、嘧菌酯与PAN质量比对微球形貌与性能的影响，并通过释放试验评价了载药微球的缓释性能。结果表明:静电纺丝机的工作电压是控制微球粒径大小的主要因素，其粒径随电压增大而减小，最小可至0.86 μm，而嘧菌酯与PAN的质量比则主要影响微球的载药量与包封率，微球载药量最高可达34.53%，包封率最高可达79.78%。此外，载药微球在3种不同pH的缓冲溶液中均实现了长达400 min的稳定释放，表明其具有出色的缓释性能。在静电纺丝机工作电压15 kV、工作距离20 cm、PAN溶液质量浓度2%、m(嘧菌酯) : m(PAN) = 1 : 2 及进样速率1.25 mL/h的条件下，可制备具有良好形貌与缓释性能的嘧菌酯/PAN微球，本研究可为农药减量增效提供一种技术路径。     

吡唑醚菌酯/二氧化硅微球的释放行为与生物活性评价

为了对二氧化硅载药体系进行评价,以吡唑醚菌酯为模式农药,利用其与正硅酸乙酯在碱性条件下的水解缩合反应,以十六烷基三甲基溴化铵(CTAB)为模板剂,制备了吡唑醚菌酯/二氧化硅微球。通过扫描电子显微镜、Nicolet iS5傅里叶变换红外光谱及高效液相色谱等表征了微球的表面形态和化学结构,测定了其在水中的光解速率;并采用透析袋法探讨了该微球在不同pH值和不同温度下的缓释行为,通过菌丝生长速率法测定了该微球对稻瘟病菌的毒力,评价了其生物活性。结果表明:所制备的吡唑醚菌酯/二氧化硅微球外观形貌较为规整,粒径在0.998~1.428 μm之间,其最大载药量可达50.73%。该微球在碱性条件下的释药速率快于酸性条件下,且其释放均符合一级反应动力学方程,在中性条件下其释药符合Ritger-Peppas方程;与pH值相比,温度对其释药速率的影响较小。给药后第5天,所制备吡唑醚菌酯/二氧化硅微球的毒力与原药相近,给药后第9天,其毒力是原药的11.7倍,缓释效果显著。该吡唑醚菌酯/二氧化硅微球在紫外灯照射10 h后光解率为38.98%,明显低于吡唑醚菌酯原药的光解率(68.92%)。     

总评“归一值”在多杀菌素·甲氨基阿维菌素苯甲酸盐聚乳酸微球制备工艺优化中的应用

采用溶剂蒸发法制备了多杀菌素·甲氨基阿维菌素苯甲酸盐聚乳酸微球,考察了内相聚乳酸浓度(X1)、理论载药量(X2)和搅拌速率(X3)对微球载药量、包封率、粒径、跨距及5 d释放率的影响。用数学方法将试验设计中的多指标"归一"化,采用中心多点等距设计法,对各指标以及总评"归一值"进行二项式拟合,描绘三维效应面,用Design-expert V8.06软件对总评"归一值"较佳的试验条件进行预测。结果表明,当聚乳酸质量浓度和搅拌速率减小、以及理论载药量增大时,总评"归一值"增大。经预测,当聚乳酸质量浓度为77.79 mg/mL、理论载药量(质量分数)为51.06%、搅拌速率为560.91 r/min时,总评"归一值"理论值达到最大(0.681 1)。依据上述较佳条件制备的微球总评"归一值"实测值为0.630 8,与理论预测值的偏差为-5.03%,其中包封率为84.49%,粒径7.19μm,跨距为1.134,5 d释放率为52.95%。微球表面光滑,DSC测试结果表明,其有效成分与微球骨架结合完好。表明研究建立的数学模型可用来预测多杀菌素·甲氨基阿维菌素苯甲酸盐聚乳酸微球的较优配方。     

溶剂挥发法制备甲氨基阿维菌素苯甲酸盐微球

以甲氨基阿维菌素苯甲酸盐(以下简称甲维盐)为芯材,以生物可降解材料聚乳酸(PLA)为壁材,采用溶剂挥发法制备了甲维盐缓释微球,分别考察了反应温度、芯壁材质量比、聚乳酸质量浓度对微球形态、粒径、载药量和包封率的影响。结果表明:在聚乳酸质量浓度和芯壁材质量比值固定不变时,温度保持20 ℃,微球的粒径、载药量、包封率均达到最佳;而固定其他条件不变,若增加聚乳酸的质量浓度,则微球的载药量、包封率和粒径也随之增加;当芯壁材质量比由1∶1变化到1∶5时,微球粒径和载药量均逐渐减小,而包封率则在芯壁材质量比为1∶1至1∶4之间逐渐增大,最大值为97.8%。电镜扫描结果显示,当芯壁材质量比在1∶3至1∶5之间时,微球呈现光滑完整的球形。差示扫描量热检测结果显示,甲维盐和聚乳酸能够有机地结合为一体。微球释药性研究表明,甲维盐聚乳酸微球具备明显的缓释性能。     

毒死蜱-聚乳酸微球的制备及其性能评价

以毒死蜱为芯材,以生物可降解材料聚乳酸(PLA)为载体(壁材),采用溶剂挥发法制备了毒死蜱缓释微球,考察了芯壁材质量比及聚乳酸浓度对微球质量的影响。结果表明:当聚乳酸浓度增加时,载药量和包封率、粒径均随之增加;当芯壁材质量比减小(由1∶2减小至1∶5)时,微球粒 径、载药量也逐渐减小;包封率在芯壁材质量比为1∶3和1∶4时分别为89.88%±1.67%和90.55%±1.86%;当芯壁材质量比小于1∶2时,微球呈光滑完整的球形。差示扫描量热检测分析证明,毒死蜱和聚乳酸能够有机地结合为一体。表明合适的芯壁材比例和聚乳酸浓度有利于提高制备微球的质量。     

嘧菌酯微囊的制备及其性能表征

以生物可降解的壳聚糖(CS)和DL-丙交酯为原料,利用开环聚合法合成了可降解的壳聚糖-聚乳酸接枝共聚物(CS-co-PLA),并以其为壁材,以嘧菌酯为芯材,以聚乙烯醇(PVA)为连续相稳定剂,采用乳化溶剂挥发法制备了不同粒径的嘧菌酯微囊,研究了芯壁材质量比、PVA质量分数、油水相比例、剪切速率及时间对微囊形态、粒径及分布、包封率和载药量的影响,测定了典型微囊的缓释性能,探讨了微囊制备工艺条件及粒径调控方法。结果表明:在PVA质量分数为1%,m(嘧菌酯):m(CS-co-PLA)=1∶4~1∶1,V(油相)∶V(水相)=1∶10,剪切乳化时间为5 min时,在3 000~18 000 r/min之间通过调节剪切速率,可制备出形状规则、粒径在280 nm~4.5μm之间并具有良好缓释性能的嘧菌酯微囊;其中剪切速率是影响微囊粒径的主要因素。     

氟乐灵微球的制备及其控释效果研究

为了延缓氟乐灵降解速率,延长其持效期,以正硅酸乙酯（TEOS）为二氧化硅源,以吐温-60为表面活性剂,采用乳液法将氟乐灵包裹在二氧化硅中,制备了氟乐灵微球,同时考察正硅酸乙酯与氟乐灵间的质量比及吐温-60质量分数对包封率及其缓释性能的影响,同时建立了温度和pH值对控释性能影响的多级释放模型。结果表明:形成的二氧化硅微球为1 μm左右的规则球形,粒径分布较窄,负载率可达50%。氟乐灵微球有效降低了氟乐灵原药的降解速率,且随着温度及pH值的升高,氟乐灵的释放速率加快。该研究不仅提高了农药稳定性,延长了其持效期,对其他农药微球的制备也有一定的借鉴作用。     

1%甲氨基阿维菌素苯甲酸盐微囊悬浮剂制备工艺研究

为促进甲氨基阿维菌素苯甲酸盐 (简称甲维盐) 微囊悬浮剂的工业化生产,以脲醛树脂为壁材,采用原位聚合法制备了1%甲维盐微囊悬浮剂,对溶剂、乳化剂及其用量、搅拌速率、酸化时间、固化温度、预聚体溶液甲醛-尿素比例 [n (甲醛) : n (尿素)] 及用量等因素进行了优化。结果表明:采用[m (环己酮) : m (200# 溶剂油)=1 : 2] 的复配溶剂,在复配乳化剂  [m (农乳603# ) : m (农乳500# )=5 : 1] 质量分数为2.4%,搅拌速率300 r/min,调酸时间120 min,固化温度70 ℃,预聚体溶液n (甲醛) : n (尿素) 为3 : 1、质量分数20%条件下,可制得外观形态良好的甲维盐微囊,其包封率达83.8%,平均粒径为2.3 μm。经高效液相色谱法测定,证明其缓释性能良好,在测试条件下可持续释放17 d。同时,针对小菜蛾3龄幼虫的生物测定试验表明,该微囊悬浮剂具有良好的缓释杀虫活性,与对照药剂甲维盐微乳剂相比具有更长的持效期。     

嘧菌酯·苯醚甲环唑PBS/PLA微球的结构表征与释放性能

以PBS/PLA共混物为复合载体,嘧菌酯和苯醚甲环唑为包埋有效成分,聚乙烯醇(PVA-1788)为分散剂,采用溶剂挥发法制备了嘧菌酯·苯醚甲环唑PBS/PLA微球。通过光学显微镜、扫描电子显微镜、Nicolet 6700型傅立叶变换红外光谱仪、高效液相色谱(HPLC)等表征复配农药微球的性质,采用透析袋法测定其缓释性能。结果表明,所得的嘧菌酯·苯醚甲环唑PBS/PLA微球中嘧菌酯的载药量和包埋率分别为14.30%、85.06%,苯醚甲环唑的载药量和包埋率为9.47%、90.18%,且微球球形规整,平均粒径为7.20μm。嘧菌酯·苯醚甲环唑PBS/PLA微球具有良好的缓释性能,并且2种活性成分的释放量之比与其最佳复配比接近,可以达到增效目的。     

多杀霉素-壳聚糖共聚物微球的制备及性能评价

以壳聚糖和DL-丙交酯为原料合成新型载体材料CS-co-PLA,通过纳米沉淀法制备多杀霉素载药粒子。利用高效液相色谱研究不同聚合物和药物质量比对载药量和包载率的影响以及载药粒子在不同环境条件下的控制释放性能。实验结果表明:多杀霉素载药粒子粒径分布均匀,具有良好的缓释性能。     

Adsorption of acetanilide herbicides on soils and its correlation with soil properties

The adsorption of metolachlor, acetochlor, pretilachlor and butachlor, as a group of acetanilide herbicides, on eight soils with various physical and chemical properties was studied. The adsorption isotherms fit the Freundlich equation well. The extent of adsorption increased in the order: metolachlor < acetochlor < pretilachlor < butachlor. The product of the Freundlich adsorption constants, K_f(1/n), showed good correlation with organic matter content (OM) of soils for each of these herbicides, suggesting that the latter is the main factor controlling the adsorption process of these acetanilide herbicides. Multivariant correlation regression between K_f(1/n) and two factors, water solubility (S_w) of herbicides and OM, was also performed. K_f(1/n) correlated well with 1/S_w and OM/S_w, showing that high S_w corresponds to a weak tendency to adsorb on soils. IR spectra and ESR parameters confirmed that multifunctional H bonds and charge-transfer bonds between humic acids (HA) and the herbicides were the main adsorption mechanisms of the latter. The ability of herbicides to form these adsorption bonds with HA increased in the same order as the extent of adsorption. © 1999 Society of Chemical Industry     

控制释放制剂的组成对异丙甲草胺释放速率的影响

将海藻酸盐与膨润土复合作为载体制备除草剂异丙甲草胺的控制释放制剂,研究了载药量、载体原料配比、膨润土类型等制剂组成因素对异丙甲草胺释放速率的影响。采用Ritger和Peppas方程分析释放动力学过程,计算50%的异丙甲草胺被释放所需时间(t50),并以此表征释放速率。结果表明,采用海藻酸盐/膨润土复合载体时, t50随载药量和载体原料配比不同介于29.4~68.0 h 之间,控制释放效果明显优于单纯以有机改性膨润土作载体(t50=5.9 h)。将有机改性膨润土与海藻酸盐复合作载体时,t50可达110 h。释放动力学方程的n值(0.436~0.496)接近Fickian扩散模型,说明该控制释放制剂中异丙甲草胺的释放过程主要受到扩散控制。     

海洋芽孢杆菌可湿性粉剂配方的优化

为提高海洋芽孢杆菌B-9987可湿性粉剂(WP)的润湿性和悬浮率,降低其pH值,通过助剂筛选、混料设计试验等方法优化了制剂配方。结果表明:以十二烷基硫酸钠作为该可湿性粉剂的助剂时,助悬浮及助润湿效果明显;通过混料设计试验确定了该可湿性粉剂固体介质的最佳配比(质量分数)为:十二烷基硫酸钠9.54%,轻质碳酸钙83.74%,高岭土6.72%;其预测悬浮率为75.15%,pH为8.62,润湿时间89.40 s,验证试验结果悬浮率为73.13%,pH 8.33,润湿时间100.00 s,二者比较接近。优化后的海洋芽孢杆菌可湿性粉剂不需经过高耗能的气流粉碎过程即可达到农药可湿性粉剂标准的要求,可明显降低生产成本。     

黄腐酸对乙草胺生物活性及持效期的影响

采用玉米根长法或芽长法研究了黄腐酸对乙草胺的生物活性、持效期和除草效果的影响.结果显示:乙草胺浓度和玉米根芽生长呈明显负线性关系,乙草胺浓度与根芽的线性方程为Y1=0.098x1+9.449和Y2=0.079x2+22.255,相关系数R1=-0.9916、R2=-0.9809;黄腐酸能够提高乙草胺的生物活性和除草效果,并延长乙草胺的持效期,添加0.25%～4.00%黄腐酸,乙草胺抑制玉米芽长和根长的活性分别提高7.12%～14.27%和6.32%～11.65%,其持效期延长0.46～12.17天:施药后28天,添加0.5%～2.0%的黄腐酸使乙草胺防除稗草的鲜重抑制率提高11.93%～16.88%.     

Use of bentonite and humic acid as modifying agents in alginate-based controlled-release formulations of imidacloprid

In order to prepare a formulation to be used for controlled release, imidacloprid was incorporated into alginate granules by using calcium chloride as gellant. The formulation prepared (alginate–imidacloprid–water) was modified by the addition of different sorbents. The effects on release rate of the addition of natural bentonite desiccated at 105 °C, untreated, acid-treated with sulfuric acid solutions over a concentration range between 0.5 mol dm⁻³ and 2.5 mol dm⁻³, and a commercial humic acid, were studied by immersion of the granules in water under static conditions. The time taken for 50% of the active ingredient to be released into water, (T₅₀), was calculated from the data obtained. On the other hand, the sorption–desorption processes of imidacloprid from a 0.01 M aqueous calcium chloride solution at 25 °C, by natural, acid-treated bentonite samples, and humic acid, have been studied by using batch experiments in order to evaluate the potential of these materials for their application in controlled-release formulations of pesticides. The experimental data have been fitted to the Freundlich equation in order to calculate the adsorption capacities (K_f). K_f values ranged from 1.76 mg kg⁻¹ for the untreated bentonite up to 126.9 mg kg⁻¹ for the humic acid. A correlation study was performed with T₅₀, the surface area (S) and the Freundlich parameter (K_f) of the bentonite samples in order to know the factors that affect release rate of imidacloprid from bentonite granules. A linear correlation of the T₅₀ values and both S and K_f parameters was observed. © 1999 Society of Chemical Industry     

一品红花卉上烟粉虱的序贯抽样技术研究

烟粉虱[Bemisiatabaci(Gennadius)]在花卉一品红上的为害十分猖獗,在调查分析的基础上,研究了烟粉虱在一品红上的序贯抽样技术。结果表明:烟粉虱成虫的平均拥挤度*m与平均密度x-回归方程为*m=-9.05+2.26x-,相关性极显著(0.799 1);以Iwao的序贯抽样为基础,结合Kuno的序贯抽样,提出复序贯抽样技术,防治指标上下限为T′₀(n)=7n+2 5.39n,T″₀(n)=7n-2 5.39n,截止线为T(n)=α+1/(D₀²-β-1/n),D₀=0.15。     

油菜和小麦种苗根系对乙草胺的耐性差异分析

为揭示油菜和小麦根系对乙草胺耐药性差异的原因,采用水培法研究了梯度浓度乙草胺对油菜和小麦种苗根系形态、根尖生理代谢和解剖结构的影响。结果表明,1 mg/L乙草胺对油菜根长抑制率为33.63%,而对小麦根长抑制率可达55.22%;100 mg/L乙草胺对油菜侧根抑制率为63.03%,而对小麦侧根抑制率达100.00%;经0.01 mg/L乙草胺处理后的油菜根尖细胞膜透性高于小麦,当乙草胺浓度高于0.1 mg/L后,小麦根尖细胞膜透性剧烈增加且高于油菜;在较高浓度乙草胺胁迫下,小麦根尖抗氧化酶活性均低于油菜;10 mg/L乙草胺处理下,小麦根尖的解剖结构变异较油菜明显,表现为细胞排列松散、混乱,根冠变形,分生组织细胞染色程度变浅,伸长区细胞分化提前,中柱鞘细胞木质化。研究表明,小麦的根系建成比油菜更容易受乙草胺抑制,且侧根数比根长更敏感;油菜和小麦对乙草胺耐药性差异可能与细胞膜透性、抗氧化酶活性以及根尖细胞组织分化等差异有关。     

Generation of pathogenic F1 progeny from crosses of Phytophthora infestans isolates differing in ploidy

Ten Phytophthora infestans isolates were analysed for maximal growth rate (μ_max), sporulation capacity (K), ploidy and the ability to produce infective F₁ progeny when combined in different crosses on tomato leaflets. Ploidy was determined using three different methods: simple sequence repeats (SSR, microsatellites), allele quantification at F382Y in the RNA polymerase, and flow cytometry. Eight out of 10 isolates were classified as diploid, the other two as triploid. There was no correlation between ploidy, growth rate and sporulation capacity although the latter was rather low for triploid isolates. Ten crosses were investigated in tomato leaflets (five 2n × 2n; four 2n × 3n; one 3n × 3n). Oospore production was observed in all crosses independent of parental ploidy. Germination and pathogenicity of oospores were investigated by measuring the number of infection sites (pathogenic F₁ progeny) over a time period of 72 days. All crosses containing a triploid parent produced many fewer F₁ isolates than 2n × 2n crosses. The generation of pathogenic F₁ progeny isolates was best for 2n × 2n crosses. A total of 319 F₁ offspring were produced and analysed for mating type and ploidy; a subset was tested for ploidy with all three methods. For 2n × 2n crosses, the majority of offspring were diploid, whereas in crosses containing one or two triploid parents, diploid, triploid and trisomic offspring were observed. The results suggest that less pathogenic F₁ progeny isolates are produced if at least one parent is triploid.     

有机改性膨润土对乙草胺的吸附与控制释放作用

首次尝试将十六烷基三甲基铵盐阳离子改性的有机膨润土(CTMAB-Bents)用作乙草胺的吸附剂和控制释放载体。结果表明,与原土(Na-Bent)相比,CTMAB-Bents对乙草胺的吸附能力提高3~5倍,且吸附能力与改性膨润土所用CTMAB量成正相关。吸附等温曲线符合Freundlich经验方程,相关系数R>0.99,吸附能力主要取决于乙草胺在水和有机膨润土间的分配作用。与Na-Bent相比,CTMAB-Bents可以显著抑制乙草胺的释放速率,对乙草胺的半数释放时间(t50)介于20CTMAB-Bent制剂的6.57 h与100CTMAB-Bent制剂的19.0 h之间,并随改性膨润土对乙草胺吸附能力的提高而延长。释放动力学曲线符合Ritger和Peppas方程,n值(0.429~0.618)接近Fickian扩散模型,说明乙草胺在有机膨润土中的释放主要受到扩散控制。