乳状液膜法萃取氨基酸的研究

本文以ＴＯＭＡＣ为载体，ＥＣＡ４３６０Ｊ为表面活性剂，内外相Ｃｌ＾－浓度梯度为推动力，研究了Ｌ－苯丙氨酸在乳状液膜体系中的传输，并对影响液膜萃取的各种因素进行了系统的阐述，确定了此体系的最佳膜相组成的实验条件，实现了Ｌ－苯丙氨酸的提取和浓缩。     

载体对氧化亚铁硫杆菌氧化活性的影响及生物量分析

载体的选择对氧化亚铁硫杆菌的固定化至关重要,选择活性炭、煤矸石、陶粒和沸石4种载体,考察这4种载体在不同添加量下对氧化亚铁硫杆菌氧化活性的影响,并分析载体表面附着的生物量.结果表明,这4种材料均可作为细菌固定化培养的载体材料.在载体添加量为25～75 g/L条件下,载体对细菌生长过程中Fe2 浓度变化影响最大,随载体添加量的增加,Fe2 氧化速率增加,而对pH变化和Eh变化无明显影响.单位重量的活性炭、陶粒和沸石的生物量高于单位重量煤矸石的,但随载体添加量的增加,其生物量减小;对煤矸石,随载体添加量的增加,其生物量增加.     

固定化微生物技术及其在重金属废水处理中的应用

固定化微生物技术是一种有效的废水生物处理技术.较为全面地介绍了其定义、分类及载体选择.全面系统地介绍了固定化微生物(主要是菌类和藻类)技术近年来在重金属废水处理中的应用现状,分析认为,固定化微生物技术对于处理含各种重金属离子的废水均有很广阔的应用前景,并对今后的研究方向做了探讨.     

玉米粒为载体的流化床生物膜反应器处理印染废水

以废弃玉米粒为载体,在生物膜流化床试验装置上进行印染废水处理试验研究。结果表明,与炉渣载体比较成膜时间缩短2 d;形成的生物膜生长到载体内部,结合牢固;曝气量(20~30 L/h.L)受流化状况控制,比非生物质载体时略大,玉米粒含量为2~4 g/L时,COD、色度和浊度的去除率分别为72%、85%和86%。     

Carrier detection of duchenne muscular dystrophy through analysis of dna from deciduous teeth of a dead affected child

The sister of a child affected by Duchenne muscular dystrophy (DMD) was referred for genetic counselling to assess the risk of her being a carrier. Her brother had died 15 years previously at the age of 8. There were no other affected males in the family. There were no methods for DNA investigation at the time of the child's death and the family had never been studied for linkage with polymorphic probes on the chromosomal region Xp21. The only tissue from which an assessment of the risk could be made by DNA linkage analysis was two of the child's deciduous teeth that the parents had kept. DNA was extracted using a protocol described for the recovery of ancient DNA from museum specimens and archaeological finds. Multiplex amplification did not reveal deletions in 19 exons spanning the hot-spot regions for deletions within the dystrophin gene in Xp21. Linkage analysis using three highly polymorphic microsatellites demonstrated that the sister had not received the X chromosome borne by her brother. These results show that DNA extracted from teeth is a reliable source for molecular diagnosis.     

负载型TiO2/活性炭的制备及光催化降解罗丹明B研究

通过溶胶-凝胶方法以活性炭(AC)为载体,制备负载型TiO2/AC,利用SEM、BET、XRD、Ranme、XPS对TiO2/AC的组成、结构、尺寸等特征进行分析和表征,并用紫外灯为光源,通过TiO2/AC、TiO2粉末和活性炭与TiO2粉末的混合物对可溶性罗丹明B的光催化降解效果的比较,探讨了TiO2/AC的光催化性能.结果表明,负载体中的TiO2是由30～60nm的球形颗粒组成,含有Ti,O,C等3种元素,颗粒间不发生团聚,其中一些C元素是由活性炭载体扩散到TiO2颗粒中的.由于活性炭载体与TiO2的协同作用以及高浓度Ti3+的影响,负载型TiO2/AC的光催化活性大.当TiO2/AC在250℃空气中热处理2h,再在氮气保护下500℃热处理2 h,TiO2的质量分数为(18±0.3)%时,负载型TiO2/AC对罗丹明B的光催化降解的表观反应常数k最大,为0.0077 min-1.     

掺杂ZrO_2、TiO_2、γ－Al_2O_3对Pt、Pd／Al_2O_3燃烧

运用ＸＲＤ、ＢＥＴ、ＤＴＡ等测试技求，研究并考察了掺杂ＺｒＯ＿２、ＴｉＯ＿２、ｒ－Ａｌ＿２Ｏ＿３对Ｐｔ－Ｐｄ／Ａｌ＿２Ｏ＿３燃烧催化剂性能的影响，结果表明，ＺｒＯ＿２对Ａｌ＿２Ｏ＿３晶相的γ型转为α型有明显的抑制作用，而ＴｉＯ＿２的添入则起促进作用；高温引起催化剂活性下降的主要原因是作为第一载体的Ａｌ＿２Ｏ＿３的比表面积和孔容减少以及Ａｌ＿２Ｏ＿３晶态从γ型转为α型所造成的。     

纳米TiO2薄膜在不同基质表面的负载及光催化性能

以釉面陶瓷和普通钠钙玻璃为载体,用溶胶凝胶法在其表面进行了纳米TiO2薄膜的负载.采用X射线衍射法(XRD)、扫描电子显微镜(SEM)和X射线光电子能谱仪(XPS)对薄膜进行了表征与分析.结果表明,TiO2为完全的锐钛矿型,平均粒径约为15nm;TiO2薄膜在2种载体上分布均匀,膜厚约为300nm;TiO2薄膜在釉面陶瓷表面呈连续分布,而在玻璃表面上出现了破裂现象;2种载体中的一些基质离子在TiO2薄膜均有渗透.光降解实验表明,2种载体上的TiO2薄膜对亚甲基蓝的降解均符合一级反应动力学.TiO2/釉面陶瓷催化活性大于TiO2/玻璃,该薄膜对实际生产多菌灵废水具有催化降解作用.2种载体上的TiO2薄膜重复使用20次,对亚甲基蓝的去除率降低约2%.     

Gene therapy for cystic fibrosis: Will it affect the uptake of prenatal carrier screening?

We report a study which examined whether the decision of 135 couples to accept prenatal cystic fibrosis (CF) carrier screening would be influenced by the advent of gene therapy. A majority (91 couples; 67 per cent) felt that gene therapy for CF would not influence their decision to be screened. Twenty-two couples (16 per cent) stated that they would decline to be screened and an equal number felt ambivalent. Even if the life expectancy of a CF sufferer were increased by gene therapy to normal, 78 per cent of couples would still wish to avail themselves of prenatal carrier screening. A majority of women who decline screening do so because they are opposed to termination of pregnancy. The availability of gene therapy could increase the proportion of couples who accept screening.     

DNA-based prenatal carrier detection for group a xeroderma pigmentosum in a chorionic villus sample

DNA-based prenatal carrier detection of group A xeroderma pigmentosum (XP-A) is reported. Chorionic villus sampling was done at the tenth gestational week in a pregnant woman whose first child suffers from XP-A. Genomic DNAs from the villi, proband, and parents were PCR (polymerase chain reaction)-amplified using three sets of primers, because the PCR and a subsequent enzyme digestion with HphI, AlwNI, or MseI may detect the three most frequent mutations of the XP-A complementing gene (XPAC) in Japanese XP-A patients. The results showed that the proband is a homozygote and that the parents and fetus are heterozygotes for a base substitution at the 3′ acceptor site of intron 3 of XPAC, indicating that the fetus is a healthy carrier of XP-A. This is the first case of prenatal carrier detection of the disorder.