Relation of Mineralizable N to Organic N Components in Dark Loessial Soils

Mineralizable N and organic N components in different layers (0～15, 15～30,30～45, 45～60, 60～80 and 80～100 cm) of six soils with different fertilities sampled from YongshouCounty, Shaanxi Province, China, were determined by the aerobic incubation method and the Bremnerprocedure, respectively. Correlation, multiple regression and path analyses were performed to studythe relation of mineralizable N to organic N components. Results of correlation and regressionanalyses showed that the amounts of the N mineralized were parallel to, and significantly correlatedwith, the total acid hydrolyzable N, but was not so with the acid-insoluble N. Of the hydrolyzableN, the amino acid N and the ammonia N had a highly consistent significant correlation with themineralized N, and their partial regression coefficients were significant in the regressionequations, showing their importance in contribution to the mineralizable N. The amino sugar N, onthe other hand, had a relatively high correlation with the mineralized N, but their partialregression coefficients were not significant in the regression equations. In contrast, thehydrolyzable unknown N had no such relations. Path analysis further indicated that the amino acid Nand ammonia N made great direct contributions to the mineralized N, but the contributions of theamino sugar N were very low. These strongly suggested that the mineralized N in the soils tested wasmainly from the hydrolyzable N, particularly the amino acid N and ammonia N which are the majorsources for its production.

调神益气针法对睡眠剥夺大鼠ADMA/DDAH/NO途径及认知障碍的影响

目的:从非对称性二甲基精氨酸/二甲基精氨酸二甲胺水解酶/一氧化氮(asymmetric dimethylarginine/dimethylarginine dimethylaminohydrolase/nitric oxide,ADMA/DDAH/NO)途径探究调神益气针法对睡眠剥夺大鼠认知障碍的影响。方法:制备大鼠睡眠剥夺模型,随机分为模型组、假针刺组及针刺组,另取无处理大鼠为对照组。治疗结束后采用Morris迷宫、八臂迷宫实验检测各组大鼠学习认知功能,Griess法检测海马NO含量,酶联免疫吸附法检测海马ADMA水平,实时荧光定量PCR和蛋白免疫印迹法检测海马DDAH mRNA和蛋白表达水平。结果:与对照组比较,模型组大鼠逃避潜伏期、完成八臂迷宫总时间、工作记忆错误次数、参考记忆错误次数、海马NO含量显著增加,正确次数、海马ADMA水平、DDAH mRNA及蛋白表达水平显著降低(P<0.05);与模型组比较,针刺组大鼠逃避潜伏期、完成八臂迷宫总时间、工作记忆错误次数、参考记忆错误次数、海马NO含量显著减少,正确次数、海马ADMA水平、DDAH mRNA及蛋白表达水平显著增加(P<0.05);与假针刺组比较,针刺组大鼠上述各项指标差异也均有统计学意义(P<0.05)。结论:调神益气针法可减轻睡眠剥夺大鼠认知障碍,可能与调节ADMA/DDAH/NO途径有关。

Enzymatic Hydrolysis of Defatted Mackerel Protein with Low Bitter Taste

Ultrasound-assisted solvent extraction was confirmed as a novel,effective method for separating lipid from mackerel pro-tein,resulting in a degreasing rate (DR) of 95% and a nitrogen recovery (NR) of 88.6%.To obtain protein hydrolysates with high ni-trogen recovery and low bitter taste,enzymatic hydrolysis was performed using eight commercially available proteases.It turned out that the optimum enzyme was the ‘Mixed enzymes for animal proteolysis’.An enzyme dosage of 4%,a temperature of 50℃,and a hydrolysis time of 300 min were found to be the optimum conditions to obtain high NR (84.28%) and degree of hydrolysis (DH,16.18%) by orthogonal experiments.Glutamic acid was the most abundant amino acid of MDP (defatted mackerel protein) and MDPH (defatted mackerel protein hydrolysates).Compared with the FAO/WHO reference protein,the essential amino acid chemical scores (CS) were greater than 1.0 (1.0 1.7) in MDPH,which is reflective of high nutritional value.This,coupled with the light color and slight fishy odor,indicates that MDPH would potentially have a wide range of applications such as nutritional additives,functional ingredients,and so on.

A Combined System for Biological Removal of Nitrogen and Carbon from Nylon-6 Production Wastewater

A combined system consisting of hydrolysis acidification, denitrification and nitrification reactors was used to remove carbon and nitrogen from the nylon - 6 production wastewater, which was characterized by good biodegradability and high nitrogen concentration. The influences of Chemical Oxygen Demand （COD） in the influent, recirculation ratio, Hydraulic Residence Time （HRT） and Dissolved Oxygen （DO） concentration on the system performances were investigated. From results it could be seen that good performances have been achieved during the overall experiments periods, and COD, Total Nitrogen （TN）, NH^＋ -N and Suspended Solids （SS） in the effluent were 53, 16, 2 and 24 mg· L^-1, respectively, which has satisfied the first standard of wastewater discharge established by Environmental Protection Agency （EPA） of China. Furthermore, results showed that operation factors, viz. COD in the influent, recirculation ratio, HRT and DO concentration, all had important influences on the system performances.

亚热带天然阔叶林凋落物分解过程中活性、惰性碳氮的动态特征

为最大程度模拟森林凋落物分解实际状况,探究亚热带天然阔叶林凋落物的分解动态特征,该研究采用凋落物分解“三明治”法,在野外原位分解的凋落物上,平均间隔3个月在积累的凋落物上铺设一层尼龙网(60目,1.2 m×1.95 m)。3年后共获取11层不同分解程度的凋落物,分析其活性和惰性碳、氮含量变化。结果表明:1)在整个分解过程中,活性、惰性碳参与分解的时间不同,水溶性有机碳最早开始释放,持续释放时间长(295d);惰性碳分解滞后(4层,422d);而酸水解有机碳可能在分解中受二者的影响,变化波动大。2)与碳相比,氮在整个分解阶段的动态更为复杂,表现出明显的周期性,即固持(1-3层,90-295 d)—释放(4-6层,422-670 d)—固持(7-11层,802-1200 d)。3)凋落物原状分解有利于氮的截留和保存。一方面,分解前期上层凋落物中的活性物质受淋溶作用在下层积累,从而降低淋失的风险;另一方面,分解后期惰性碳氮偏向于底层积累,利于碳氮的固存。可见,森林凋落物的自然分解状态有利于凋落物惰性碳氮更好地归还土壤。因此,在森林管理中要注重凋落物层的保护,让其在自然状态下分解,助力土壤碳氮的稳定与保留。

水解-复合生物滤池工艺处理盐化工工业废水

采用水解酸化池和两级复合生物滤池工艺处理盐化工工业废水。挂膜在启动29 d后成功。在水力负荷为0.37～0.74 m/h(不包括回流)、回流比为100%以及气水比为3∶1的条件下,COD、NH3-N、TN和SS的出水浓度(去除率)分别为78 mg/L(60%)、1.05 mg/L(93.4%)、18.9 mg/L(63.8%)和4.9 mg/L(94.5%),达到设计标准,实现了对盐化工工业废水的二级生物处理。装置具备一定的抗负荷能力,在实验范围内水力负荷(0.37～0.74 m/h)的增加有利于污染物的去除;通过工艺沿程水质记录,分析了COD、NH3-N、TN和SS在水解酸化区、一级缺氧/好氧区及二级缺氧/好氧区的贡献。