酸碱法纯化红三叶草中总异黄酮的工艺

采用酸碱法及醇溶水沉法对红三叶草中总异黄酮进行了纯化工艺的研究,分别考察碱溶pH、酸沉pH、水沉加水量对异黄酮含量及浸膏得率的影响。再通过正交实验得到最佳纯化工艺条件为:碱溶pH=8.5,酸沉pH=2.5,加水量为异黄酮醇溶液的6倍量时,异黄酮质量分数可达50%以上。     

基于碱溶酸沉法的亚麻籽油蛋白分离工艺优化

将亚麻籽油作为原料,选择碱溶酸沉法进行蛋白分离。先基于胶酶法对亚麻籽油进行脱胶预处理,在粉碎脱脂之后,通过碱溶酸沉法,进行亚麻籽油蛋白分离工艺优化,从提取pH、料液比、时间、温度四要素对其在亚麻籽油蛋白分离提取率中的影响做了详细分析。通过研究证明,亚麻籽油蛋白分离工艺的最佳参数为:提取液pH=9.5;温度50℃;料液比1∶30;时间为60 min,在此工艺条件下,蛋白分离提取率高达51.66%,蛋白质量分数高达92.28%。     

Box-Behnken响应面法优化阿里红总多糖水提醇沉工艺

分别采用单因素实验和Box-Behnken响应面法对阿里红总多糖水提醇沉工艺条件进行优化。以苯酚-硫酸法测定阿里红总多糖含量,在单因素实验基础上,选择多糖提取率为评价指标,以浸泡时间、提取时间、加水倍量作为考察因素,采用Box-Behnken响应面法优化水提工艺条件;选择多糖含量为评价指标,以醇沉浓度、醇沉时间、浓缩倍数为考察因素,采用Box-Behnken响应面法优化醇沉工艺条件;采用Sevage法对阿里红粗多糖进行脱蛋白。得到最佳水提工艺条件为:加水10倍,浸泡时间1.5 h,提取1.0 h,提取1次;最佳醇沉工艺条件为:浓缩倍数10倍,醇沉浓度80%,醇沉时间12 h;Sevage法脱蛋白,蛋白脱除率为42.4%,多糖保留率为61.4%。建立的阿里红总多糖提取纯化工艺简单可靠。     

发酵液中吩嗪-1-羧酸的初步分离工艺

通过考察吩嗪-1-羧酸(PCA)在不同pH值下的溶解度,利用PCA碱溶酸沉的性质,采用絮凝法去除发酵液中的大分子蛋白质和菌丝体等杂质,初步分离出代谢产物PCA;研究了絮凝剂用量、发酵液稀释倍数、pH值及温度对过滤速度、终产品PCA含量和回收率的影响. 结果表明,当以聚氯化铝为絮凝剂、发酵液稀释4倍、絮凝pH值为8.5、絮凝温度为30℃时,所得产品中PCA含量达69.9%,产品对发酵液的PCA回收率为91.3%.     

微生物发酵法制备的豆粕中大豆分离蛋白提取

采用碱提酸沉法对微生物发酵法制备的豆粕中提取大豆分离蛋白,并用凯氏定氮法测算大豆分离蛋白含量。研究碱提温度、液固比和碱提p H值及酸沉温度、时间和p H值对大豆分离蛋白提取率的影响。结果表明碱提的最佳工艺条件为:温度50℃、时间50 min、液固比10∶1、p H=9.0。酸沉的工艺参数为:温度45℃、时间40 min、p H=4.5。所得大豆分离蛋白最高提取率为79.29%。     

云南昆明的槐米中芦丁的提取及纯化探究

采取碱溶酸沉法提取槐米中的芦丁,探究了提取温度、pH值和析出静置时间。结果表明:最佳温度为80℃、酸沉时的pH值为3.5～4,析出的静置时间为24 h。紫外可见分光法在最大吸收波长250 nm处测定,标准曲线法绘制芦丁对照品曲线,相关系数R~2为0.9991。结果为:c(粗品)=0.0429 mg/mL,c(精品)=0.0560 mg/mL,A(精品)=1.504,A(粗品)=1.13,粗品的质量为26.8125 mg,精品的质量为35.0000 mg,粗品的含量为65.3%,精品的含量为89.0%。     

腐殖酸对钴、镉作用的研究

采用碱溶酸沉法提取土壤中的腐殖酸,研究其对Co2+、Cd2+的吸附作用机理。结果表明,最佳pH值为6～7,吸附过程属于放热过程。该腐殖     

大豆蛋白质的提取技术的研究进展

大豆蛋白质含有人体所必需的八种氨基酸,并具有优良的食品性能和营养价值,是一种重要的植物蛋白,在食品工业中得到了广泛的应用,是近年来的研究重点。其中,大豆蛋白的提取方法有碱溶酸沉法、酶解法、乙醇提取法、离子交换法、超滤膜分离法、发酵法等等。本文以研究方向和工艺改进两方面为着力点综述了碱溶酸沉法和酶解法这两种主要的提取方法的发展脉络。     

多晶硅水性切削液除硅研究

以废切削液回收PEG后剩余的废砂为原料,采用酸溶和碱溶两种方法除去废砂中的多晶硅杂质,回收SiC微粉,并对两种方法的可行性及工艺条件进行了研究。结果表明,酸法除硅时,当HF浓度为4 mol/L,硝酸浓度为2 mol/L,温度为35℃,反应时间为70 min时,可使回收微粉中硅杂质含量在0.1%~0.2%。碱法除硅时,当NaOH的溶液3%左右,温度在70℃,反应时间2 h,可使回收微粉中硅杂质含量在0.2%~0.3%。粒度分析表明,酸法及碱法回收产品粒径分布均能满足指标要求,且碱法回收产品粒径分布与新砂一致。     

调节pH纯化磺胺间甲氧嘧啶的工艺探讨

磺胺间甲氧嘧啶是一种人工合成、在兽医临床上使用最广泛的高效抗菌药之一。某公司磺胺间甲氧嘧啶生产线所得产品含量为74%～76%,常规手段纯化困难。磺胺间甲氧嘧啶结构含有伯氨基、磺酰胺基团,表现出酸碱两性,利用碱溶酸沉法通过调节反应溶液的pH,改变磺胺间甲氧嘧啶在水溶液中溶解度(存在状态),将反应杂质与磺胺间甲氧嘧啶分离,达到纯化的目的。实验结果显示:磺胺间甲氧嘧啶的产率与介质溶液的pH密切相关,在8.0～10.0区间内随pH的升高而增大,但纯度则相反。在pH=8.5～9.0范围进行调节,可以得到纯度在95%以上且产率满意的结果。     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

基于ATRP法制备的触角状亲水性羟胺树脂的吸硼性能的研究

以大分子引发剂氯乙酰化聚苯乙烯微球(PS-acyl-Cl)经原子转移自由基聚合(ATRP)法引发丙烯酰胺(AM)和甲基丙烯酸缩水甘油酯(GMA)单体的共聚接枝,制得一种触角状亲水性环氧载体(PS-acyl-g-P(AM-co-GMA)),再经二乙醇胺(DEA)的环氧基开环胺化反应,得到一种含多个-NCH2CH2OH螯合配基的多齿-五元螯合环的触角状亲水性羟胺树脂(PS-acyl-g-P(AM-co-GMA)-DEA)。将此树脂用于硼吸附研究,结果表明,PS-acyl-g-P(AM-co-GMA)-DEA树脂对硼的吸附满足Langmuir方程,为单分子层吸附;饱和吸附量约为37.7 mg·g-1,且树脂5 min即可达到吸附平衡,与其它已报道的吸硼树脂相比,该树脂具有更高的吸附量和吸硼速率。吸附动力学研究表明,树脂吸附硼的过程主要由颗粒扩散过程控制。重复使用5次后该树脂的吸附量基本不变,解吸率均在90%以上,重复使用性能良好。