Alkaloids from Cyrtanthus elatus

The alcoholic extract of the fresh bulbs of Cyrtanthus elatus yielded zephyranthine (1) and 1,2-O-diacetylzephyranthine (2), together with three other known alkaloids. Complete assignment of 1H and 13C NMR spectra of compounds 1 and 2 was done by employment of two-dimensional NMR techniques.     

Fourier transform infrared spectra of drying oils treated by irradiation

Drying oils, such as linseed oil and tung oil, have the potential as coating materials to improve barrier properties of biobased packaging films. Oil drying is a chemical reaction in which polyunsaturated fatty acids undergo autoxidation. During drying, oils polymerize and form water-resistant films. However, drying rates tend to be too slow for practical applications. Metal driers are used in the paint industry to accelerate drying, but often driers are not safe for food contact. The objective of this work was to investigate the effect of ionizing radiation on the oxidation or drying rate of drying oils. The effect of irradiation dose on the drying rate of linseed and tung oils was monitored by FTIR spectroscopy. The peak at 3010 cm (-1) was found to be a useful index of oxidation rate. The decrease in peak intensity with time was fitted with exponential functions of the form Abs = Abs 0 exp (- t/ k), where Abs 0 is the initial absorbance and 1/ k is the rate constant for the oxidation process. Values for k were 9.91 ( R (2) = 0.98), 6.59 ( R (2) = 0.95)n and 6.44 ( R (2) = 0.97) for radiation levels of 0, 50, and 100 kGy, respectively. The k values suggested that the oxidation rate increased as the radiation dose increased from 0 to 50 kGy. A further increase to 100 kGy had only a limited effect.     

Predicting the potential of engulfment using an on-farm grain storage hazard assessment tool

The goal of this research was to address the problem of engulfment in flowing grain in on-farm metal grain storage bins. This was accomplished using a systems approach to identify contributing factors to engulfment, which were then used to develop a 28-question Farm Grain Hazard Assessment Tool (FGHAT). A numerically weighted high- and low-risk response accompanied each question, the sum of which resulted in a potential-risk-of-engulfment score for a given on-farm grain handling and storage system. The assessment tool was pilot tested on a sample of 47 farms. The difference between the mean scores of farms with a history of engulfment (n = 14) and the mean scores of farms with no prior reported engulfment incident (n = 33) was significant (p < or = 0.001). This finding suggests that it is possible, using the hazard assessment tool, to predict the increased likelihood of an engulfment in a specific on-farm grain storage and handling system. It was also found that the management of grain during storage and an individual's perception of risk and willingness to avoid flowing grain hazards had the most significant impact on reducing the potential for an engulfment. In contrast, a history of grain plugging problems was not found to make a considerable difference in scores between the two groups of farms. The presence of stirring devices in bins, accommodation for lockout devices on electrical controls, and using grain storage bins smaller than 20, 000 bu capacity also had little impact on the difference in scores. Based upon the level of significance of each of the 28 questions'ability to predict an increased risk of engulfment, it was concluded that a valid response could be obtained with as few as eight questions. Recommendations concerning continued study and application of the tool were formulated, including the effectiveness of the tool in changing the farmers' behavior, and the findings also contributed to the revision of a potential engineering standard for on-farm grain storage structures.     

Determination of total folate in plant material by chemical conversion into para-aminobenzoic acid followed by high performance liquid chromatography combined with on-line postcolumn derivatization and fluorescence detection

A procedure involving chemical conversion of all forms of folate present in plant material into para-aminobenzoic acid (PABA) and a liquid chromatographic-fluorimetric determination with on-line postcolumn derivatization is reported. All folates are cleaved with liberation of PABA by hydrogen peroxide followed by acid hydrolysis using concentrated hydrochloric acid (37%) at 110 degrees C for 6 h. The reaction yield for individual folates conversion to PABA ranged from 44.4 to 97.3%. PABA could be determined sensitively by on-line postcolumn derivatization with fluorescamine, the detection limit for PABA being 3.02 nM. On the basis of this principle, a method for the determination of total folate in plant material, including a purification step on an affinity column, is presented, which offers a sufficient sensitivity and selectivity for routine analysis of total folate in natural samples. The total folate contents of tomatoes, carrots, white cabbage, and spinach were determined, and the results were quite comparable to the data reported. The recovery of PABA and the comparison of total folate analysis in spinach on different occasions (over 6 months) are also reported. The method is reliable, universal for all folates, including polyglutamate and monoglutamate forms, and eliminates the need for a deconjugation step and multiple conversion reactions.     

Nonabsorbable dietary fat enhances disposal of 2,2',4,4'-tetrabromodiphenyl ether in rats through interruption of enterohepatic circulation

Polybrominated diphenyl ethers are lipophilic persistent organic pollutants (POPs), which accumulate in the environment, leading to human exposure. The compounds exert a negative impact on human health. Strategies to prevent or diminish their accumulation in humans are required. We investigated in rats whether the disposal rate of 14C-labeled tetrabromodiphenyl ether (BDE-47) could be enhanced by increasing fecal fat excretion through dietary treatment with nonabsorbable fat (sucrose polyester, SPE). As compared to control rats, SPE treatment increased fecal excretion rates of fat (+188%, p < 0.05) and 14C-BDE-47 (+291%, p < 0.05). On the basis of biliary secretion and fecal excretion rates of 14C-BDE-47, SPE effectively inhibited the enterohepatic circulation of 14C-BDE-47. In conclusion, dietary supplementation of nonabsorbable fat can enhance excretion of hydrophobic POPs by interruption of their enterohepatic circulation. Our data indicate that this strategy could decrease concentrations of hydrophobic POPs in the human body and thereby their impact on human health.     

沈阳地区大豆田蛴螬在土壤中的分布调查

为调查大豆田蛴螬分布情况,采用九宫格法,分别于春季、大豆苗期和秋季开展实地挖土调查。结果表明,4月30日蛴螬还潜于土深30 cm以下,至大豆播种时最浅已上行至土深5～10 cm处;在大豆幼苗阶段,蛴螬的为害区域集中在土壤深度0～5 cm范围内,5 cm以下虫量为0;9月末开始,蛴螬逐渐下潜,至10月10日大豆采收时集中在土深10 cm以上范围内活动,抓住此时机进行调查,即可作为预测当年越冬基数的理论依据。     

辽宁省花生病虫害发生现状及发展趋势

综述了辽宁省目前花生生产中发生严重的褐斑病、网斑病、疮痂病、蛴螬、花生蚜虫等主要病虫害的发生症状、引起的病原菌、害虫种类及发生规律和危害损失情况。     

不同磷肥处理和干旱胁迫对大豆蚜种群发生及大豆结荚量的影响

采用盆栽试验法,探讨不同施磷水平、不同程度干旱对大豆蚜种群发生及大豆结荚量的影响.结果表明,在高磷处理下,大豆蚜种群增长最快.与中磷和高磷处理相比较,低磷处理下的大豆单株有效结荚量和非正常结荚量均存在显著差异(P＜0.05),低磷处理下的大豆植株有效结荚量最多.于旱胁迫处理下大豆植株上发生的蚜量低于正常供水处理(CK),单株有效结荚量在此2个处理间存在显著差异(P＜0.05),前者处理下的单株有效结荚量为3.4个,后者为8.8个;单株非正常结荚量在2个处理间也存在显著差异(P＜0.05),分别为7.4、2.7个/株.