腐蚀电池法强化后续生化工艺处理印染废水

从腐蚀电池反应的基本原理出发,以腐蚀电池反应中的溶铁量作为外部监控指标,来探求腐蚀电池反应的最佳工艺条件。以循序间歇式活性污泥法(SequencingBatchReactor,SBR)为主体处理方法,在对比SBR法和腐蚀电池法-SBR法处理印染废水降解效果的基础上,重点考察了腐蚀电池对后续生化工艺的影响。研究表明,腐蚀电池法不仅提高了废水的可生化性,而且强化了后续生物处理中的活性污泥,使得腐蚀电池-SBR法在COD、色度去除率上明显高于SBR法。     

Keratinase production and keratin degradation by a mutant strain of Bacillus subtilis

A new feather-degrading bacterium was isolated from a local feather waste site and identified as Bacillus subtilis based on morphological, physiochemical, and phylogenetic characteristics. Screening for mutants with elevated keratinolytic activity using N-methyl-N＇-nitro-N-nitrosoguanidine mutagenesis resulted in a mutant strain KD-N2 producing keratinolytic activity about 2.5 times that of the wild-type strain. The mutant strain produced inducible keratinase in different substrates of feathers, hair, wool and silk under submerged cultivation. Scanning electron microscopy studies showed the degradation of feathers, hair and silk by the keratinase. The optimal conditions for keratinase production include initial pH of 7.5, inoculum size of 2% （v/v）, age of inoculum of 16 h, and cultivation at 23 ℃. The maximum keratinolytic activity of KD-N2 was achieved after 30 h. Essential amino acids like threonine, valine, methionine as well as ammonia were produced when feathers were used as substrates. Strain KD-N2, therefore, shows great promise of finding potential applications in keratin hydrolysis and keratinase production.     

A Novel Degradation Pathway of Zn(dmid)(phen)_2 in Pyridine

0Introduction Overthepast20years,continuousattentionshavebeenpaidtothemetalcomplexesofmulti sulfurlig ands[1,2],thereactivitiesofthesecomplexesarewellknownandusedtosynthesizemanynovelcomplexes.How ever,unstablepropertiesofthesecomplexeshaveinhabitedtheira…     

N-Monomethyl-arginine and nicotinamide prevent streptozotocin-induced double strand DNA break formation in pancreatic rat islets

The impact of short term in vitro exposure to the diabetogenic drug streptozotocin on pancreatic islet glucose metabolism, insulin secretion, DNA fragmentation and cell viability, was studied. Streptozotocin impaired cell viability as well as insulin secretion and the oxidation of glucose. These effects were partially counteracted by inhibition of the inducible form of nitric oxide synthase with N-monomethyl-arginine and by scavenging oxygen free radicals with nicotinamide. Isolated islets underwent double strand DNA fragmentation after 24 h in culture. The degree of DNA breakdown was strongly enhanced by exposure of the islet DNA was obtained with N-monomethyl-arginine and nicotinamide. These data suggest that the generation of reactive oxygen and nitrogen species is involved in the deleterious action of streptozotocin on pancreatic islet tissue. A role for oxygen radicals generated during streptozotocin-induced islet cell damage as possible mediators of the expression of the inducible form of nitric oxide synthase and the scavenging action of nicotinamide on these radicals, is then proposed.     

胆红素光敏反应对腹水型肝癌细胞DNA的降解作用

胆红素光敏反应对腹水型肝癌细胞ＤＮＡ合成具有明显的抑制作用，对ＤＮＡ分子具有明显的降解作用降解作用随胆红素浓度的增加，照光时间的延长而加剧。避光组细胞ＤＮＡ分子也有一定的降解，但照光组的降解作用明显高于避光组。     

丙烯睛—卤代羧酸共聚物热解过程的研究

采用付里叶变换红外光谱法在位连续测定了含羧酸及由代羧酸丙烯腈共聚物在低温热解时化学结构的变化，根据光谱特征峰随温度增加的变化规律。测定了裂解产物中残留的氰基量及环化度和环化序列长度。结果表明，溴代羧酸丙烯腈共聚物具有独特的性能。在可用于碳纤维原丝的共聚体中，是具有较大潜力的竞争者。     

脉冲介质阻挡放电降解三氯乙烯的研究

研究了不同操作条件下脉冲介质阻挡放电等离子体对三氯乙烯的降解效果,通过红外分析探讨了降解的反应历程.结果表明:当载气为N2时,脉冲介质通过阻挡放电等离子体可实现三氯乙烯的有效降解,降解率随放电参数及气体流量的变化而变化,在保证体系能量效率最大的基础上可获得三氯乙烯降解的最佳处理条件,即输入电压25 V、脉冲频率500 Hz、脉冲占空比50％、放电间隙5 mm、气体流量300 mL/min;当载气中含O2时,三氯乙烯的降解率随输入电压的变化而变化,即输入电压小于25 V时,三氯乙烯降解率随O2的增加而提高,输入电压大于25 V时,三氯乙烯降解率随O2的增加而下降.三氯乙烯降解过程中会产生CHCl2 COCl、CCl3-CN或ClCH2CH2NH2,终产物中除含有HCl、CO2和CO外,还含有COCl2.     

分子印迹壳聚糖/TiO2光助催化剂选择性降解孔雀石绿

以钛酸丁酯、壳聚糖为原料,孔雀石绿为模板分子,用溶胶-凝胶法制备了孔雀石绿分子印迹的壳聚糖/纳米TiO2催化剂( MA-CHS/TiO2),在紫外灯照射下催化降解孔雀石绿等底物,考察了印迹型催化剂对孔雀石绿等底物的光催化降解性能,并与相关非印迹型体系作比较,利用傅里叶红外光谱(FTIR)、X射线粉末衍射(XRD)方法对其结构进行了表征.结果表明,印迹型催化剂具有明显的选择催化效应,在降解目标分子底物时,表现出比非印迹型更高的催化活性,其光催化降解速率常数可比非印迹型增加约69％;而在降解非目标分子底物时,印迹型催化剂不具选择催化效应,其催化活性与非印迹型相似.     

Factors Affecting Soil Organic Carbon Density （SOCD） and Total Nitrogen Density （TND） in Inner Mongolian Steppe

在内蒙古草原区选取94个样点,涵盖耕地、退耕地、人工林和草原4种土地利用类型,根据土壤质地将草原细分为沙质草原和非沙质草原。通过对这些样点土壤有机碳密度（SOCD）和全氮密度（TND）的研究,发现在内蒙古草原区,SOCD主要受到土壤质地的影响,黏粒（〈2gm）、粉砂（2～16μm）和细粉砂（16～63μm）的含量越高,SOCD越高。而TND同时受到土壤质地和土地利用类型的影响,分布在非沙质土壤的草原具有最高的TND。耕作不会导致SOCD显著降低,但是会造成TND降低。人工林不能显著提高土壤养分含量,相反,由于人工林对养分和水分的需求很大,可能导致土壤肥力的降低。此外,草原区温度越高,土壤养分越低,这预示着在全球变暖的背景下,这一地区的土壤可能成为重要的碳源。植被退化越严重,土壤养分越低,因此保护草原区的植被免受过度放牧的影响非常重要。     

Preparing Ca-P coating on biodegradable magnesium alloy by hydrothermal method: In vitro degradation behavior

Magnesium alloys are potentially attractive biodegradable materials.However,their rapid corrosion rate limits their biomedical application.To slow down the rate of biodegradation,a protective calcium-phosphate coating was formed on a magnesium alloy substrate by a hydrothermal method.Scanning electron microscope results showed that the coating consisted of two layers with different crystalline characteristics.The loose outer layer showed a prism-like crystal structure,while the compact inner layer is a dense ultra-fine regular di-pyramid-like structure with an average grain dimension of ～200 nm.The compositions of the inner layer and outer layer were calcium-deficient hydroxyapatite (Ca-def HA) and dicalcium phosphate (DCPa),respectively.The coating adhered well to the substrate with a thickness of about 15 m.Immersion in Hank’s solution indicated that the coating could significantly improve the degradation properties of magnesium alloy.The pH of the solution containing the coated samples increased much more slowly than the untreated control.After 8 d immersion,the uncoated sample had corroded seriously while the coated sample was much less corroded.The Ca/P atom ratio in both the layers of the coating increased and the coating was still protecting the substrate.The two layers of the coating corroded differently because of differences in solubility.The outer layer was more severely attacked and many holes were formed on the surface,the inner layer suffered less attack.In addition,a growth of precipitate on the inner layer was observed,indicating that surface bioactivity was improved by the coating.Thus,magnesium alloys coated with a Ca-P coating prepared by a hydrothermal method are promising candidate biodegradable biomaterials,and further investigation of in vivo degradation behavior is suggested.