Prenatal diagnosis of non-ketotic hyperglycinemia

We describe successful prenatal diagnosis in four pregnancies at risk for non-ketotic hyperglycinemia, two affected and two unaffected, using the glycine level and the glycine/ serine ratio in amniotic fluid obtained at 16 weeks gestational age. Although this method of prenatal diagnosis for non-ketotic hyperglycinemia has been effective in our hands the narrow differences between affected and unaffected pregnancies indicate the need for caution concerning its reliability.     

Large-scale production of poly(3-hydroxyvaleric acid) by fermentation ofChromobacterium violaceum,processing, and characterization of the homopolyester

A fed-batch process was developed, which allowed biotechnological production of the homopolyester poly(3-hydroxyvaleric acid) [poly(3HV)], in a mineral salts medium containing valeric acid as carbon source and complex nutrients as supplements byChromobacterium violaceum at a 10- and 300-L fermentation scale. This process yielded up to 40 g dry cell matter per L fermentation broth, and the cells contained up to 70% (w/w) poly(3HV). Poly(3HV), which was extracted from the cells with chloroform and was precipitated from this solvent with ethanol, was processed to test bars by injection molding or by press processing and to fibers by melt spinning. The unprocessed and processed poly(3HV) material was characterized with respect to the molecular weight and with respect to thermal, rheological, and mechanical properties. It was shown that it is possible to process biodegradable poly(3HV) thermoplastically and to obtain a polymer suitable for applications with low strength requirements.     

缫丝废液的综合利用

缫丝废液中含有丰富的蛋白质，直接排入严重污染环境，废液中的蛋白质能用化学或生物化学方面水解成有用的氨基酸，后者是化学，医药，食品，饲料工业的重要原料，本文报道了缫丝废液中蛋白质酸水解和酶水解的研究结果以及部分酶水解的规律。     

The effect of salinity on waste activated sludge alkaline fermentation and kinetic analysis

The effect of salinity on sludge alkaline fermentation at low temperature(20°C) was investigated, and a kinetic analysis was performed. Different doses of sodium chloride(Na Cl, 0–25 g/L) were added into the fermentation system. The batch-mode results showed that the soluble chemical oxygen demand(SCOD) increased with salinity. The hydrolysate(soluble protein, polysaccharide) and the acidification products(short chain fatty acids(SCFAs), NH+4–N, and PO_4~(3-)–P) increased with salinity initially, but slightly declined respectively at higher level salinity(20 g/L or 20–25 g/L). However, the hydrolytic acidification performance increased in the presence of salt compared to that without salt.Furthermore, the results of Haldane inhibition kinetics analysis showed that the salt enhanced the hydrolysis rate of particulate organic matter from sludge particulate and the specific utilization of hydrolysate, and decreased the specific utilization of SCFAs. Pearson correlation coefficient analysis indicated that the importance of polysaccharide on the accumulation of SCFAs was reduced with salt addition, but the importance of protein and NH+4–N on SCFA accumulation was increased.     

重庆主城区PM2.5中羧酸的季节变化和来源分析

本文针对重庆主城区4个采样点PM2.5中羧酸开展研究,通过GC-MS分析,定量分析了16种饱和脂肪酸、21种不饱和脂肪酸和8种二元羧酸等多种物质的浓度水平,进而对羧酸的季节变化及来源进行了探讨.羧酸日均总浓度为130.42~1953.79 ng·m~(-3),一元脂肪酸和二元羧酸在各采样点浓度差异显著.一元脂肪酸呈明显的季节变化,夏季最高(961.97 ng·m~(-3)),冬季最低(49.24 ng·m~(-3)).饱和脂肪酸中偶数碳优势明显,以C_(16)(棕榈酸)和C_(18)(硬脂酸)最为丰富.二元羧酸也呈明显的季节变化,在冬季最高(432.04 ng·m~(-3)),春季最低(64.57 ng·m~(-3)).二元羧酸以丙二酸、丁二酸和戊二酸为主.细菌活动和烹饪油烟对一元脂肪酸具有较大的贡献,光化学氧化作用则对二元羧酸贡献较大.     

气相色谱法测定水中九种卤代乙酸类化合物研究

建立了液-液萃取气相色谱-双柱-双检测器法测定水中九种卤代乙酸类化合物的检测方法.40 ml水样经4 ml甲基叔丁基醚两次萃取,萃取液经10%硫酸-甲醇50℃衍生后,用气相色谱电子捕获检测器检测.方法检出限为0.6~1.0μg/L,加标回收率75.9%~111%,6次测定的相对标准偏差≤16%.两次萃取显著提高了一氯乙酸和一溴乙酸的回收率,双柱-双检测器有效排除实际样品中假阳性结果,检测结果更准确可靠.     

挥发性脂肪酸的滴定测量方法进展

测定挥发性脂肪酸(Volatile fatty acid,VFA)浓度的方法包括:蒸馏法、比色法、气相色谱法以及各种滴定法。就常规监测和控制而言,滴定法在简洁、省时和成效比方面要优越于其它测试方法。滴定法测定VFA主要包括四点滴定法、五点滴定法和八点滴定法。这些方法主要应用于厌氧反应器中高浓度VFA的测定,但随着活性污泥数学模型的应用,城市污水中低浓度VFA的测量越加重要,是模型应用不可缺少的条件。文章具体介绍了上述三种滴定方法的基本原理、优缺点和应用情况,为适用于城市污水中VFA测量提供参考。     

Perfluorinated compounds in common carp (Cyprinus carpio) fillets from the Upper Mississippi River

Ten different perfluoroalkyl acids (PFAAs), including perfluooctane sulfonate (PFOS), were measured in 30 common carp (Cyprinus carpio) fillets collected from three sites on the Upper Mississippi River in Minnesota in an effort to evaluate the potential impact of PFAA emissions in this area. Samples upstream of the city of St. Cloud (reference site) had median PFOS concentrations of 8.1 ng/g wet weight (ng/g wet wt), but median levels increased significantly downstream in the Minneapolis-St. Paul urban area, with concentrations from the Pig's Eye Lake site at 26 ng/g wet wt (p=0.0015) and the Spring Lake site at 40 ng/g wet wt (p=0.0004). This latter PFOS concentration is within the advisory range for limiting fish consumption to one meal a week according to the Minnesota Department of Health. Other PFAAs were also found to increase significantly between the reference site and the Minneapolis-St. Paul area, but maximal concentrations remained below 2.0 ng/g wet wt. This study demonstrates the bioaccumulation of PFAAs in a ubiquitous fish species in a major urban area known to have historical inputs of various PFAA compounds. The full extent of this contamination and the potential for accumulation in other species remain to be evaluated.     

京密引水中天然有机物的形态

用改进的Ｌｅｅｎｈｅｅｒ分离方法，并引入最新的ＸＡＤ－８，ＸＡＤ－４树脂串联技术，将京密引水中有机物定量分离为悬浮和溶解态两大类。后者又进一步分离为憎水有机物、腐殖酸类，ＸＡＤ－４酸和亲水中性有机物等形成。溶解态有机物含量约为３ｍｇＣ／ｌ，其中一半左右为腐殖酸类。ＸＡＤ－４酸占溶解态有机１５－２０％，非极性憎水有机物所占比例很低。     

Primary sludge stabilisation with calcium hydroxide

We studied the effect of the addition of calcium hydroxide to primary raw sludges. Calcium hydroxide enhances ammonia release as well as proteins and fats hydrolysis from the sludge organic material during stabilisation process. Changes in the molecular composition of the sludge extractable lipids caused by calcium hydroxide suspension, analysed using gas chromatography interfaced to mass spectrometry detector, are discussed. Calcium hydroxide treatment selectively removes fatty acids from the sludge lipids, while it has little effect on removal and molecular assemblage of the stanol and sterol compounds during sludge stabilisation. Biogenic n-alkanes are minor components in the sludge lipids.