SBA-15／PMMA杂化材料力学性能及热性能研究

采用溶胶一凝胶法制备了二维六方介孔结构的SBA-15,利用原位分散聚合法制备（SBA-15／0wt％DBP／PMMA,SBA-15／15wt％DBP／PMMA和SBA—15,25wt％DBP／PMMA）三种三维纳米网络结构的杂化材料。通过FT—IR、XRD、TEM、DSC和SEM等方法对SBA-15／DBP／PMMA杂化材料进行了表征。结果表明：DBP和SBA-15的加入对PMMA分子链的化学结构未造成任何影响,且SBA-15在PMMA基体中仍能保持介观有序结构;SBA-15对脆性PMMA具有较好的增强增刚作用,且DBP的含量越高,杂化材料拉伸强度和模量提高程度相对减小;三种杂化材料的rrg均随SBA-15含量的增加而提高,且DBP的含量越高,杂化材料的Tg提高幅度越小。     

Adenovirus Terminal Protein Contains a Bipartite Nuclear Localisation Signal Essential for Its Import into the Nucleus

Adenoviruses contain dsDNA covalently linked to a terminal protein (TP) at the 5′end. TP plays a pivotal role in replication and long-lasting infectivity. TP has been reported to contain a nuclear localisation signal (NLS) that facilitates its import into the nucleus. We studied the potential NLS motifs within TP using molecular and cellular biology techniques to identify the motifs needed for optimum nuclear import. We used confocal imaging microscopy to monitor the localisation and nuclear association of GFP fusion proteins. We identified two nuclear localisation signals, PV(R)6VP and MRRRR, that are essential for fully efficient TP nuclear entry in transfected cells. To study TP–host interactions further, we expressed TP in Escherichia coli (E. coli). Nuclear uptake of purified protein was determined in digitonin-permeabilised cells. The data confirmed that nuclear uptake of TP requires active transport using energy and shuttling factors. This mechanism of nuclear transport was confirmed when expressed TP was microinjected into living cells. Finally, we uncovered the nature of TP binding to host nuclear shuttling proteins, revealing selective binding to Imp β, and a complex of Imp α/β but not Imp α alone. TP translocation to the nucleus could be inhibited using selective inhibitors of importins. Our results show that the bipartite NLS is required for fully efficient TP entry into the nucleus and suggest that this translocation can be carried out by binding to Imp β or Imp α/β. This work forms the biochemical foundation for future work determining the involvement of TP in nuclear delivery of adenovirus DNA.     

长江下游原水臭氧-生物活性炭深度处理效果及有机物特性变化

以长江下游镇江征润洲段为原水,利用中试装置研究臭氧-生物活性炭(O3-BAC)组合工艺优化运行及其对有机物特性变化的影响。结果表明:当调整主臭氧投加量为2.5 mg/L时,深度处理工艺对CODMn、NH4^+-N和两类消毒副产物前体物(TTHMFP、THAAFP)的去除率分别为68.5%、86.7%、57.3%和48.9%;同时,从净水过程中有机物特性变化对消毒副产物影响的角度,提出应将强疏水性小分子有机物作为镇江市饮用水处理的控制主体。     

浅析DBP／DIBP丁醇回收汽提塔的加热方式

详细论证DBP／DIBP废水丁醇回收汽提塔的加热方式,提出革除汽提塔再沸器,将直接蒸汽冲管代替再沸器加热的方案,并从理论上证明了此项技术改造的可行性,认为此项技术改造能使汽提塔加热蒸汽耗量降降低14．31％,同时,论述了此项技术改造对汽提搭塔理论板层数,填料情况及工艺控制条件的影响。     

高浓度邻苯二甲酸二丁酯废水的破乳絮凝性能研究

1,4-丁二醇(BDO)废水中的邻苯二甲酸二丁酯(DBP)是一类典型的环境激素,如何高效去除废水中DBP是BDO行业废水稳定运行的关键。重点研究了不同破乳絮凝剂及其浓度、絮凝时间等对BDO废水的浊度、色度、COD、DBP等去除性能的影响。研究结果表明,3~#破乳絮凝剂(丙烯酸十八酯-丙烯酰胺共聚物)质量浓度为500 mg/L、絮凝时间为5 min时,BDO废水的浊度由6 700 NTU降低至48 NTU,浊度去除率达99.28%;色度由2 450mg/L降低至1 490 mg/L,色度去除率为39.18%;COD由93 730.48 mg/L降低至14 443.57 mg/L,COD去除率达84.59%;DBP由3 210 mg/L降低至26 mg/L,DBP去除率达99%,具有良好的破乳絮凝性能。     

稳定性同位素稀释气相色谱-质谱法测定白酒中DBP、DEHP含量及不确定度评定

采用稳定性同位素稀释气相色谱-质谱法对白酒中DBP、DEHP的含量进行测定,并对整个测试过程的不确定度来源进行系统分析。样品提取、离心后取上层有机相进行测定,利用选择离子监测模式,以氘代同位素标记物作内标,以m/z 149和m/z153为定量离子对,对其定性定量测定,并对测试过程中引入的各个分量进行评定与合成。结果表明,DBP、DEHP在0.2~2.0 mg/L浓度范围内线性关系良好,r≥0.999,定量限为0.05 mg/kg,不同加标水平中的平均回收率为DBP:91.2%~100.4%,RSD为2.24%~2.79%(n=5);DEHP:99.0%~110.6%,RSD为4.98%~5.44%(n=5)。当DBP测定结果为0.572 mg/kg时,扩展不确定度为0.040 mg/kg,DEHP测定结果为0.251 mg/kg时,扩展不确定度为0.025 mg/kg,k=2,p=95%。该方法准确可靠,可用于白酒中DBP、DEHP的含量测定。并且建立的不确定度评定方法可用于气相色谱-质谱法测定白酒中DBP、DEHP浓度的不确定度评估。标准溶液配制和标准曲线拟合、样品前处理以及分析仪器是主要的不确定度来源。     

Achieving proportional DiffServ per‐hop behaviour with PLQF

We propose a novel scheme that can provide both delay and loss proportional DiffServ per‐hop behaviour. DiffServ is a framework that can provide different QoS levels to different groups of network users, and eliminate the shortcoming of the best‐effort delivery in today's Internet. The scheme employs probabilistic longest queue first (PLQF) as its forwarding and dropping mechanism. PLQF mainly reacts immediately to the queue‐length fluctuation of each service class, and then decides the probability for each QoS class, which determines the forwarding or dropping behaviour. We couple delay and loss differentiated services in one scheme. The proposed scheme is proven to achieve proportional differentiated services after detailed evaluations. Furthermore, the implementation cost of PLQF is much less than that of the previously proposed schemes, such as WTP and PLR. Copyright © 2003 John Wiley & Sons, Ltd.     

分子蒸馏脱除核桃油中塑化剂工艺优化

为探索利用分子蒸馏脱除核桃油中塑化剂的合理工艺,采用单因素实验考察了蒸馏温度、进料速度和刮膜转速对核桃油中塑化剂DEHP和DBP脱除的影响,在此基础上以DEHP和DBP的含量为指标,运用响应面法对分子蒸馏脱除核桃油中塑化剂的工艺条件进行优化。结果表明:分子蒸馏脱除核桃油中塑化剂的最佳工艺条件为蒸馏温度150℃、进料速度250 mL/h、刮膜转速260 r/min,在此条件下核桃油中DEHP含量为0.56 mg/kg,DBP含量为0.05 mg/kg,符合我国对食品中DEHP、DBP的限量要求(DEHP≤1.5 mg/kg,DBP≤0.3 mg/kg)。     

ACE-inhibitory and antihypertensive properties of a bovine casein hydrolysate

The aim of this study was to investigate the potential angiotensin converting enzyme (ACE)-inhibitory activity and the antihypertensive effect, after a single oral administration, of a pepsin hydrolysed bovine casein (HBC) and a fraction with molecular mass lower than 3000 Da (HBC < 3000). ACE-inhibitory activity was measured by spectrophotometric assay. These products were orally administered by gastric intubation. The systolic (SBP) and the diastolic blood pressure (DBP) were measured in spontaneously hypertensive rats by the tail cuff method before administration and also 2, 4, 6, 8, and 24 h post-administration. HBC showed a potent ACE-inhibitory activity. This activity was 10 times higher in HBC < 3000. HBC and HBC < 3000 decreased the arterial blood pressure of the rats. The decrease in the SBP observed for HBC (400 mg/kg) or HBC < 3000 (200 mg/kg) was less pronounced than that caused by 50 mg/kg of captopril (antihypertensive positive control). However, the maximal decreases in DBP caused by HBC or HBC < 3000 were as high as the maximum decrease observed for captopril. The antihypertensive effect of these products was transient and reverted 24 h after the administration. HBC and HBC < 3000 exert antihypertensive effect caused by small peptides with ACE-inhibitory activity.     

基于四尾栅藻毒性反应的Hg和DBP协同作用研究

目前环境监测中多采用单一指标的监测方法,对污染物质共同作用产生的环境危害监测较少。以叶绿素a含量和光能转化效率为指标,研究Hg(汞)和DBP(邻苯二甲酸二丁酯)单一及联合胁迫下的毒性作用。结果表明:Hg,DBP单一作用及联合胁迫对四尾栅藻的叶绿素荧光参数均有抑制作用,随暴露浓度的增大,微藻叶绿素a含量和光能转化效率逐渐降低,显示出明显的剂量-效应关系;Hg和DBP联合胁迫时表现出明显的对四尾栅藻的协同作用。研究成果可为污染物综合毒性监测提供理论依据。