负载型掺氮TiO_2光催化剂的制备及可见光催化活性研究

采用减压蒸馏凝胶-煅烧法制备得到纯态Ti O2、Ti O2/甲壳素、掺氮Ti O2、负载型掺氮Ti O2/甲壳素4种光催化剂,对比研究了在钠灯(中心波长589 nm)照射下对甲基橙的催化降解活性,发现纯态Ti O2、Ti O2/甲壳素、掺氮Ti O2几乎没有催化活性,负载型掺氮Ti O2/甲壳素具有较好的可见光催化活性。研究了煅烧温度、煅烧时间、体系p H值对负载型掺氮Ti O2/甲壳素催化活性的影响。结果表明,负载型掺氮Ti O2/甲壳素在煅烧温度400℃、煅烧时间2 h、初始p H值3时催化活性最佳,甲基橙的残留率为2%。     

活性炭负载TiO2的制备及其光催化性能的研究

以钛酸四丁酯（Ti（OC4H9）4）为原料,用溶胶-凝胶法制备活性炭（AC）负载（TiO2。XRD分析其晶型组成。实验研究了不同TiO2负载量、不同煅烧时间、不同煅烧温度以及不同使用次数等情况下TiO2/AC光催化剂的光催化活性。实验结果表明,当负载量为28.2%、煅烧时间为4h、煅烧温度为400℃时催化剂活性最高,甲基橙溶液的降解率到达了98.09%。同时研究表明了多次使用后的TiO2/AC光催化剂仍具有很好的光催化性能。     

微波诱导H_2O_2降解甲基橙溶液的研究

本文研究了微波诱导H2O2降解甲基橙的效果。主要考察了甲基橙初始浓度、溶液p H值、双氧水的投加量、微波辐射时间等因素对甲基橙降解率的影响。实验结果表明:甲基橙浓度为5mg/L,p H值为4,0.132mol/L的双氧水12m L,微波辐射时间为13min时,甲基橙的降解率可达100%。实验还发现微波或双氧水单独作用于甲基橙溶液,基本没有降解作用。     

La／B共掺杂Ti02光催化降解苋菜红的研究

采用溶胶-凝胶法制备La/B共掺杂Ti O2催化剂和纯TiO2催化剂。以苋菜红溶液为降解目标物,研究了La/B共掺杂TiO2为催化剂的紫外光催化反应。重点考察了La/B共掺TiO2催化剂的掺杂比、催化剂的煅烧温度、光照时间、催化剂的添加量、溶液初始浓度、溶液p H值对降解率的影响。实验结果表明：单纯只靠紫外光光照或催化剂并不能快速、有效地降解苋菜红溶液。在La和B掺杂比为1：2、催化剂的煅烧温度为600℃、催化剂用量为3.0g/L、溶液p H值为5.5、溶液初始浓度为10mg/L的苋菜红溶液200m L,紫外光光照60min的条件下,La/B共掺杂的TiO2催化剂和纯TiO2催化剂光催化脱色率分别可达99.60%、86.45%,TOC的去除率为60.06%。     

尿素为氮源制备氮掺杂二氧化钛光催化剂

以Ti(SO4)2为前驱物,尿素为沉淀剂和掺杂剂,采用水热法结合固相反应法制得了锐钛矿相掺氮纳米TiO2纳米粉体。采用XRD对制备的掺氮氧化钛结构进行了表征,以亚甲基蓝为模拟污染物,考察了不同煅烧温度制备的光催化剂在可见光照射下的光催化性能。结果表明,煅烧温度高于160℃时氮可掺进TiO2晶体中,且温度越高,掺氮量越高;煅烧温度为200℃时,氮掺杂TiO2粉体可见光催化活性最强,在波长不低于400nm的可见光作用下,对亚甲基蓝的4h降解率达62.5%。     

对甲苯磺酰肼为氮源制备氮掺杂二氧化钛光催化剂

以Ti（SO4）2为前驱物,尿素为沉淀剂,对甲苯磺酰肼为掺杂剂,采用水热沉淀法结合固相反应法制得了锐钛矿相掺氮纳米TiO2粉体。采用XRD对制备的掺氮氧化钛结构进行了表征,以亚甲基蓝为模拟污染物,考察了不同煅烧温度制备的光催化剂在可见光照射下的光催化性能。结果表明,煅烧温度高于120℃时氮可掺进TiO2晶体中,且温度越高,掺氮量越高;煅烧温度为180℃时,氮掺杂TiO2粉体可见光催化活性最强,在波长不低于400nm的可见光作用下,对亚甲基蓝的4h降解率达48.5％。     

TiO2/SiO2/NiFe2O4磁性纳米材料的制备、表征及光催化性能

采用均匀沉淀法在表面包覆了SiO2的磁基体NiFe2O4上负载TiO2,从而制备出一种新型磁性纳米光催化材料TiO_2/SiO_2/NiFe_2O_4,并通过改变pH值、水浴时间、水浴温度、煅烧温度及Ti/Ni摩尔比n(Ti):n(Ni)等得到材料的最佳制备条件。用XRD、TEM分析了复合材料的形态结构及包覆情况,结果显示TiO2均匀地包覆在SiO2/NiFe2O4表面,复合材料粒径范围为50～70nm;UV-vis吸收曲线表明,复合材料对光的吸收带出现红移。VSM测试表明复合材料具有良好的磁性,易于通过磁场进行回收。以甲基橙的水溶液为模拟污染物,评价了复合材料的光催化性能,该材料对甲基橙的脱色率达98.6%。     

H_6P_2W_(18)O_(62)/TiO_2-SiO_2光催化降解有机染料

采用浸渍法制备了H6P2W18O62/Ti O2-Si O2光催化剂,并采用傅里叶变换红外光谱(FTIR)、X射线粉末衍射(XRD)、扫描电子显微镜(SEM)对其进行了表征。通过光催化剂H6P2W18O62/Ti O2-Si O2对含甲基橙模拟废水进行处理,结果表明,H6P2W18O62/Ti O2-Si O2光催化剂表现出较高的光催化性能,在催化剂用量为1.39 g/L,甲基橙溶液质量浓度为5 mg/L,初始p H=3.5,反应时间2.5 h的条件下,甲基橙的降解率可达99.2%,且产生了协同效应。H6P2W18O62/Ti O2-Si O2光催化剂对罗丹明B、亚甲基蓝和甲基红均具有较高的光催化性能,降解率达84.0%~100.0%。光催化剂还表现出较好的重复使用性能,第5次降解率仍为94.4%。     

TiO_2-硅藻土复合光催化剂降解二甲基甲酰胺研究

以硅藻土为固体活性添加物,采用溶胶-凝胶法水解钛酸四丁酯制备硅藻土负载TiO2复合光催化剂。以二甲基甲酰胺(DMF)溶液的光催化降解为模型反应,研究制备条件中煅烧温度、溶胶pH值、H2O与Ti(OR)4的量比、涂覆次数等条件对光催化活性的影响。结果表明,合成复合催化剂的最佳煅烧温度为500℃、溶胶pH值为1.3、H2O与Ti(OR)4的量比为15.75、涂覆次数为3次;在300W紫外光照射、反应2h、催化剂投量为1g/L、DMF的质量浓度为200mg/L时,最大降解率为84.27%,表现出较强的光降解性。     

活性炭负载纳米铁的制备及对甲基橙去除效果的研究

采用液相还原法制备了活性炭负载纳米铁,对样品进行FTIR、BET、SEM、XRD表征分析,并考察活性炭、纳米铁以及活性炭负载型纳米铁对甲基橙溶液的去除效果,同时探讨初始质量浓度、投加量、溶液p H以及温度对甲基橙去除效果的影响。结果表明:纳米铁成功负载在活性炭上,对甲基橙的去除效果较明显,30 min内即可达95%的去除率,在较大范围浓度内均有良好的去除效果,同时实验表明在较低p H值和较高温度下,更有利于甲基橙的去除。     

Antitumor activity of synthetic alkylphospholipids with or without PAF activity

1-O-Octadecyl-2-O-methyl-sn-glycero-3-phosphocholine (ET-18-OMe) has been reported to possess definite antitumor activity in vivo. Twenty-two alkyl lysophospholipid analogs were chemically synthesized, and their antitumor activity against mouse experimental tumors (Sarcoma 180, MM46, P388) was examined. Among them, 1-O-octadecyl-2-O-acetoacetyl-rac-glycerol-3-phosphocholine was found to show antitumor activity similar to ET-18-OMe with less acute toxicity. Intravenous injection of the ET-18-OMe withsn-3 configuration retarded the subcutaneous growth of Sarcoma 180 cells effectively, while the growth inhibition by thesn-1 isomer was much less effective. This stereospecificity was similar to that observed in their activities as platelet-activating factor (PAF) agonists. The acetoacetyl compound, another PAF agonist, showed similar stereospecific antitumor action in vivo. These findings suggest that some alkyl lysophospholipids may activate host cells to a cytostatic stage against tumor cells in vivo through binding to a PAF receptor. Our preliminary results indicated that the responsible cells under these conditions might be primarily immature macrophages present in the bone marrow. No appreciable or even adverse stereospecificity was observed in the different sets of experiments where the activity of ET-18-OMe against MM46 tumor cells in vivo or the direct cytotoxicity against human promyelocytic leukemia HL-60 cells in vitro was examined. Under, some conditions, the antitumor activity of ET-18-OMe in vivo may be revealed through direct cytotoxicity and/or modulation of the host defense system by “nonspecific” mechanisms. Some alkylphospholipids without PAF activity may also show antitumor activity through similar, “nonspecific” mechanisms.     

Mn-CDs with oxidase activity produces ROS to inhibit cell activity

Carbon dots (CDs) played increasingly important roles in biotechnology due to their potential as alternatives of natural enzymes. However, the fabrication of highly active and durable CDs remains challenging and catalytic reaction mechanisms over CDs needs to be better clarified for future advances. Herein, we synthesized manganese-doped carbon dots (Mn-CDs, ∼5 nm) with excellent oxidase properties which exhibits stable catalytic capacity in various salt solutions at different temperatures. Moreover, by thoroughly investigating catalytic ability of Mn-CDs, we found that doped Mn atoms effectively modulated the spin density and charge distribution of CDs, thus reducing the band gap by forming intermediate energy levels. Besides, it is found that the content of pyrrolic N positively correlated to catalytic capacity of Mn-CDs. As a demonstration, the prepared Mn-CDs could work as pseudo-oxidase in real cell environment. They can easily enter into cells, induce the production of ·O₂⁻ under ultraviolet light irradiation, and eventually inhibit the activity of HeLa cells and 4T1 cells. We believe that the as-prepared Mn-CDs would find wide applications as metal-doped artificial nanozymes, and lay a foundation for the application and development of Mn-CDs.     

Effect of bamboo oil on antioxidative activity and nitrite scavenging activity

The purposes of this study were to investigate the effects of the bamboo oil on antioxidative activity and nitrite scavenging activity in vitro and in vivo. When the bamboo oil concentration was increased from 10 to 90 μL/mL, the DPPH scavenging rate increased from 15.6 to 98.2%. However, at bamboo oil concentrations above 110 μL/mL, it was not increased. The superoxide anion radical scavenging rate increased from 54.8 to 89.1% when the bamboo oil concentration increased from 110 to 150 μL/mL. When the bamboo oil was incubated for 20 h, the linoleic acid scavenging rate was approximately 91.2%, similar to that of ascorbic acid. The glutathione production using bamboo oil in vivo was 59.0 μM/g of liver, which was about 6.5-fold higher than that of the control. In the case of the activities of glutathione peroxidase and catalase, they were 16.8 U/mg of protein and 295 KU/mg of protein, respectively, approximately 5.6-fold higher and 3.0-fold higher than that of the control. The nitrite scavenging activity was increased from 60.1 to 93.9% at pH of 1.2 when the saturation time was increased from 2 months to 8 months. However, at more than 10 months of saturation, this level was not increased. These results suggest that the bamboo oil of Phyllostachys nigra var. henonis can be used in bioactive and functional materials.     

中低品位磷矿粉的机械力化学活化与活性表征

采用机械力化学法对中低品位磷矿石进行活化,考察了不同活化设备在不同活化条件下的磷活化性能,结果表明:原料磷矿石质地较致密坚硬,化学活性较低,磷浸出率非常低,只有3.1％.采用XQM2-2L变频行星球磨机机械活化,在机械活化120 min后得到了最佳的活性,磷浸出率为7.5％.采用AGO-Ⅱ高能球磨机进行实验,磷浸出率最佳值为10.9％,若在相同活化条件下,活化过程中加入助磨剂,则可进一步提高磷的浸出率,最佳值可达15.3％.     

The anthelmintic activity of the cyclotides: natural variants with enhanced activity

The cyclotides are a family of backbone-cyclised cystine-knot-containing peptides from plants that possess anthelmintic activity against Haemonchus contortus and Trichostrongylus colubriformis, two important gastrointestinal nematode parasites of sheep. In the current study, we investigated the in vitro effects of newly discovered natural cyclotides on the viability of larval and adult life stages of these pests. The natural variants cycloviolacin O2, cycloviolacin O3, cycloviolacin O8, cycloviolacin O13, cycloviolacin O14, cycloviolacin O15, and cycloviolacin O16 extracted from Viola odorata showed up to 18-fold greater potency than the prototypic cyclotide kalata B1 in nematode larval development assays. Cycloviolacin O2 and cycloviolacin O14 were significantly more potent than kalata B1 in adult H. contortus motility assays. The lysine and glutamic acid residues of cycloviolacin O2, the most potent anthelmintic cyclotide, were chemically modified to investigate the role of these charged residues in modulating the biological activity. The single glutamic acid residue, which is conserved across all known cyclotides, was shown to be essential for activity, with a sixfold decrease in potency of cycloviolacin O2 following methylation. The three lysine residues present in cycloviolacin O2 were acetylated to effectively mask the positive charge, resulting in a 18-fold decrease in anthelmintic activity. The relative anthelmintic activities of the natural variants assayed against nematode larvae correlated with the number of charged residues present in their sequence.     

Cytostatic activity of syntheticO-alkylglycerolipids

A series of halogen-containing alkylglycerolipid analogs has been checked for their cytostatic activity both in vitro and in vivo. The compounds included alkyldeoxyhaloglycerols (I), alkyldeoxyhaloglycerophosphocholines (II), and alkyldeoxyhaloglycerophosphoric acids and alkyl esters (III). While compounds I and III were moderately active, compounds II were found to have a strong inhibitory effect on the proliferation of Ehrlich ascites tumor cells in vitro. Cell growth inhibition of 50% or more was found mainly in the late S- or G₂-phase of the cell cycle as revealed by flow cytometry. Alkyl lysophospholipid analogs II and cholesterol form liposomes with high encapsulation efficiency and low permeability for entrapped substances. Compounds II were active against Lewis lung carcinoma in mice when applied in free form or as liposomes.     

Antifeedant activity of quassinoids

The antifeedant activity of 13 quassinoids of different structural types has been studied against the Mexican bean beetle (Epilachna varivestis Mulsant) 4th instar larvae and the southern armyworm (Spodoptera eridania Crawer) 5th instar larvae. All quassinoids tested displayed significant activity against the Mexican bean beetle and, thus, do not reveal a simple structure-activity relationship. Five quassinoids were active against the southern armyworm. Interestingly, four of these-bruceantin (I), glaucarubinone (VI), isobruceine A (VIII), and simalikalactone D (XI)-possess the required structural features for antineoplastic activity. The noncytotoxic quassin (X) is an exception; it is active against both pests.     

Latexes with intrinsic crosslink activity

In order to develop and study ‘two pack in one pot’ systems, i.e. binder systems consisting of a blend of complementary reactive latexes, epoxy- and amino-functional latexes were prepared and characterised, with atte lion especially directed to control of the number of functional groups and control of the molecular weight. The investigation is focused on the control of the molecular weight of epoxy-functional latexes and on the incorporation of amino groups in latexes by using amino-functional methacrylic monomers. To determine the reactivity of the epoxy and amino groups and to check which factors influence the crosslink reaction a number of blends were prepared from both solution and emulsion copolymers and dried at ambient temperatures. It was found that the major factors, which affect the efficiency of crosslinking, are the T_g and the molecular weight of the copolymers and, in the case of a ‘two pack in one pot system’, the rate of the polymer-polymer reaction in relation to that of the polymer-polymer interdiffusion.