肉类食品中磺胺类磁性纳米微粒的制备及其性能研究

Fe3O4磁性纳米粒子作为一种新型多功能材料,因其独特的磁学特性被广泛应用于材料及生物医学等领域。通过共沉淀法制备Fe3O4磁性纳米粒子,聚乙二醇(PEG)进行改性,通过计算机模拟Fe3O4晶体结构,红外光谱对样品进行分析,并进一步进行流变学、磁光性等性能研究。期望可以将磁纳米粒子与分子印迹技术相结合,制备出用于快速检测肉类食品中磺胺残留的新型磁性分子印迹材料。     

表面氨基化的Fe3O4/SiO2复合磁性纳米粒子提取白酒中羧酸的研究

利用化学共沉淀法制备磁性四氧化三铁纳米粒子,并用SiO2 和3- 氨丙基三乙氧基硅烷(APTES)依次对磁性纳米颗粒进行表面修饰,成功获得表面氨基改性后的磁性Fe3O4/SiO2 复合纳米粒子;采用红外光谱(IR)、透射电子显微镜(TEM)对氨基改性前后的Fe3O4/SiO2 复合纳米粒子的形态、结构进行表征。并利用- NH2 在常温下易与羧基反应的原理,用氨基改性后的磁性Fe3O4/SiO2 复合纳米粒子提取白酒中的羧酸类物质,用气相色谱- 质谱(GC-MS)联用对提取情况进行研究。结果表明：氨基改性后的磁性Fe3O4/SiO2 复合纳米粒子与白酒中的羧基能够发生较好的键合反应,从而实现提取白酒中羧酸的效果。     

Fe3O4@Au-Cu/金属有机框架纳米酶电化学传感器检测食品中亚硝酸盐

目的 基于类酶活性的自组装材料构建金属有机框架（Fe3O4@Au-Cu/MOF）实现食品中亚硝酸盐的检测。 方法 采用透射电子显微镜和傅里叶红外光谱对合成的Fe3O4@Au-Cu/MOF进行表征。利用循环伏安法,通过改变Fe3O4@Au-Cu/MOF添加量、温度、扫描速率以及pH值进行单因素和正交实验。根据最优体系对1~100 mmol/L的亚硝酸盐进行检测,绘制工作曲线,进行抗干扰实验和实际样品检测。 结果 合成的Fe3O4@Au-Cu/MOF具有催化活性高、暴露活性位点多和孔隙率高等优势。当Fe3O4@Au-Cu/MOF添加量为0.0075 g,温度为40°C,扫描速率为0.08 V/s,pH值为7时为最优检测体系。工作曲线为y=0.36118x+15.57962,R2=0.99603,检测限为1.6 μmol/L (S/N=3),具有较强的抗干扰性。在实际样品检测中,回收率为98.78%~102.58%,RSD小于4%。 结论 与现有方法相比,合成的Fe3O4@Au-Cu/MOF催化过H2O2产生氧化活性物质,促进亚硝酸盐氧化,增加体系中电荷移动的能力更强。该方法构建的电化学传感器具有可靠、方便、灵敏和成本低等特点,为食品中亚硝酸盐的检测提供了一种新的思路。     

液体耐磨层Al2O3表面改性及分散性的研究

强化板的耐磨性能通常由耐磨表层Al2O3颗粒决定,Al2O3颗粒在水相和有机树脂中分散性差,容易团聚沉降。表面改性可有效地增进两相界面间亲和性,提高有机树脂对无机粒子的润湿能力,改善无机颗粒的分散。选用偶联剂KH-550对Al2O3颗粒进行表面改性,考察了KH-550用量、改性时间和改性温度等对活化系数的影响。实验得出Al2O3表面改性的最佳条件:改性剂用量2.0%、改性时间80min和改性温度80℃。通过粒度分析仪对改性后Al2O3颗粒水相分散液进行分析,峰值粒径越小和微分分布比例越集中说明分散效果越好,粒度分析的结果表明与活化系数表征效果一致。     

重质碳酸钙的表面改性及其在造纸中的应用

研究重质碳酸钙表面改性的影响因素,确定了最优改性剂。对最优改性剂和淀粉对重质碳酸钙改性的工艺进行了研究,并探讨了改性剂用量、糊化温度、糊化时间、保温时间等因素对重质碳酸钙改性的影响,优化了其操作工艺条件。把制备淀粉-碳酸钙复合物加填到手抄片中,并对手抄片的物理性能进行检测,检测结果表明改性的碳酸钙对纸张的物理性能有很大的提高。     

棉织物姜黄染色工艺应用壳聚糖季铵盐改性研究

针对姜黄天然染料在棉织物表面色深度(K/S值)低、染色牢度差的问题,利用壳聚糖与2,3-环氧丙基三甲基氯化铵制备壳聚糖季铵盐阳离子改性剂对棉织物进行改性。应用色度指标分析棉织物姜黄天然染料染色敏果,通过单因素优化实验获得,改性剂对棉织物的最优改性工艺为:在浴比1:50下,改性剂用量(o.w.f)为4%,改性温度为80℃,改性时间为40min;改性后棉织物姜黄天然染料最优染色工艺为:在浴比1:50下,姜黄天然染料用量为5%(o.w.f)、染色温度为60℃、染色时间为40min。采用该改性、染色工艺所染得棉织物的K/S值大大提高。经改性后的棉织物较未改性棉织物显示良好的染色牢度,其皂洗牢度、摩擦牢度普遍提高了0.5～1级,达到了Oeko-TexStandard100标准要求。     

2,3-环氧丙基三甲基氯化铵采用浸轧法对亚/麻棉织物的改性工艺探讨

以2,3-环氧丙基三甲基氯化铵作为阳离子改性剂,采用浸轧法先对亚麻/棉混纺织物进行阳离子改性,可提高织物的上染率。本文通过研究改性剂浓度、焙烘温度、焙烘时间对改性效果的影响,得出最优的改性工艺条件。     

Fe_3O_4纳米粒子从枣皮中分离纯化花青素

针对枣皮花青素对铁离子较为敏感的现象,利用Fe3O4纳米粒子具有比表面积大,易于磁分离,对小分子可产生吸附效应等特点从枣皮中分离纯化花青素,并对其吸附条件和洗脱效果进行研究。结果表明;Fe2+:Fe3+摩尔比1.2∶2,定性温度30℃,熟化温度75℃,搅拌速度1000r·min-1,p H 9时,用油酸作改性剂,制备的Fe3O4纳米粒子效果较好;温度70℃,p H 11,时间15min下,最适吸附比为0.6g·g-1,UV检测Fe3O4纳米粒子吸附效果良好;温度20℃,p H 3,时间2h,电动搅拌下,丙酮洗脱可使Fe3O4纳米粒子与枣皮花青素完全分离,解吸附效果良好。结论;采用化学共沉淀法制备的Fe3O4纳米粒子对枣皮花青素具有良好的吸附作用,丙酮洗脱既解决了解吸附技术难题,又有效地回收了吸附剂,且工艺简单,易于操作。     

2,3-环氧丙基三甲基氯化铵采用浸轧法对亚/麻棉织物的改性工艺探讨

以2,3-环氧丙基三甲基氯化铵作为阳离子改性剂,采用浸轧法先对亚麻/棉混纺织物进行阳离子改性,可提高织物的上染率。本文通过研究改性剂浓度、焙烘温度、焙烘时间对改性效果的影响,得出最优的改性工艺条件。     

核-壳型没食子蓝磁性分子印迹固相萃取材料的合成、表征及应用研究

采用化学共沉淀法制备Fe3O4磁性纳米粒子,以3-氨丙基三乙氧基硅烷(APTES)对其表面进行氨基硅烷化改性,形成Fe3O4@SiO2-NH2纳米粒子。以其作为磁性核,采用表面印迹技术,以没食子蓝为模板,丙烯酰胺(AM)为功能单体,乙二醇二甲基丙烯酸酯(EGDMA)为交联剂,在Fe3O4@SiO2-NH2表面形成没食子蓝分子印迹聚合膜,制备了核-壳型没食子蓝磁性分子印迹聚合物(Fe3O4@MIPs)。分别采用红外光谱(FT-IR)、场发射扫描电镜(FESEM)、振动样品磁强分析(VSM)和热重分析(TGA)等仪器分析手段,对Fe3O4@MIPs的结构进行表征。研究了它对没食子蓝的吸附性能,探讨了吸附动力学、吸附等温线及分子识别性。并将其应用于食品中分离富集没食子蓝。结果表明,所制备的核-壳型磁性分子印迹聚合物具有高吸附容量(表观最大吸附量达149.32 mg/g),快速的结合动力学(60 min达吸附平衡)及显著的吸附选择性(印迹因子达9.10)。以其作为新型固相萃取材料,结合高效液相色谱(HPLC)检测,对加标食品样品中的没食子蓝进行分离、纯化、检测,加标回收率在97.69%~104.4%之间,RSD在0.85%~1.2%之间,检测限为0.0051μg/m L。在外加磁场作用下Fe3O4@MIPs可快速与样品基质分离,大大提高了实验效率。该方法简单快速,可应用于食品中非法添加的没食子蓝的分离检测。     

Construction of heterotypic cell sheets by magnetic force-based 3-D coculture of HepG2 and NIH3T3 cells

Heterotypic 3-D coculture is essential to mimic tissues and organs, because cell-cell interaction between various types of cells is believed to be important for the activation of cellular functions. In this study, magnetic force was applied to construct a 3-D coculture system of HepG2 and NIH3T3 cells as a model of hepatocytes and mesenchymal cells. Magnetite cationic liposomes (MCLs) were used to label target cells. NIH3T3 cells labeled with MCLs were seeded onto ultralow-attachment plates, whose surface is composed of a covalently bound hydrogel layer that is hydrophilic and neutrally charged. When a magnet was placed under the plate, cells accumulated on the bottom of the well. After a 24-h incubation period, the cells formed a multilayered cell sheet, which contained the major mesenchymal extracellular matrix (ECM) components (fibronectin and type I collagen), suggesting that the use of stromal NIH3T3 cells gave sufficient strength to cell sheets. Both NIH3T3 and HepG2 cells were labeled with MCLs, and cocultured by two methods: NIH3T3 cell sheets were constructed and HepG2 cells were subsequently seeded onto NIH3T3 cell sheets, and then allowed to form layered cell sheets by applying magnetic force; or NIH3T3 and HepG2 cells were mixed and then allowed to form mixed cell sheets by applying magnetic force. These heterotypic multilayered cell sheets were successfully constructed and an enhanced albumin secretion by HepG2 cells was observed. These results suggest that the new tissue engineering technique using magnetite nanoparticles and magnetic force, to which we refer to as magnetic force-based tissue engineering (Mag-TE), is a promising approach to construct multilayered cell sheets consisting of heterotypic cocultured cells.     

Magnetic force-based cell patterning using Arg-Gly-Asp (RGD) peptide-conjugated magnetite cationic liposomes

Micropatterning of target cells is highly desired for tissue engineering and cell biology. Although recent progress in surface chemistry has enabled the spatial control of cell adhesion onto substrates, conventional methods usually require specialized devices and time-consuming processes to fabricate the substrate. In this study, we demonstrate a simple and rapid cell-patterning procedure using magnetite nanoparticles and magnetic force. To label the target cells magnetically, magnetite nanoparticles were encapsulated in cationic liposomes (magnetite cationic liposomes; MCLs). To promote cell attachment, an Arg-Gly-Asp (RGD)-motif-containing peptide was coupled to the phospholipid of MCLs (RGD-MCLs). A human keratinocyte cell line, HaCaT, which has a high anchorage dependency, was used as a model. The RGD-MCLs were added to an ultralow-attachment plate, whose culture surface is modified with a covalently bound hydrogel layer that is hydrophilic and neutrally charged, and then HaCaT cells were seeded to the plates. The RGD-MCLs induced cell adhesion, spreading, cytoskeletal organization, and fibronectin expression. When steel plates with a 200 microm width placed on a magnet were set under a culture surface, magnetically labeled cells aligned on the surface where the steel plate was positioned, resulting in cell patterning. Furthermore, various cell patterns using a computer-aided design were successfully fabricated. These results suggest that cell patterning using RGD-MCLs is a promising approach to tissue engineering and studies in cell biology.     

Dissolution and reduction of magnetite by bacteria

Magnetite (Fe3O4) is an iron oxide of mixed oxidation state [Fe(II), Fe(III)] that contributes largely to geomagnetism and plays a significant role in diagenesis in marine and freshwater sediments. Magnetic data are the primary evidence for ocean floor spreading and accurate interpretation of the sedimentary magnetic record depends on an understanding of the conditions under which magnetite is stable. Though chemical reduction of magnetite by dissolved sulfide is well known, biological reduction has not been considered likely based upon thermodynamic considerations. This study shows that marine and freshwater strains of the bacterium Shewanella putrefaciens are capable of the rapid dissolution and reduction of magnetite, converting millimolar amounts to soluble Fe(II)in a few days at room temperature. Conditions under which magnetite reduction is optimal (pH 5-6, 22-37 degrees C) are consistent with an enzymatic process and not with simple chemical reduction. Magnetite reduction requires viable cells and cell contact, and it appears to be coupled to electron transport and growth. In a minimal medium with formate or lactate as the electron donor, more than 10 times the amount of magnetite was reduced over no carbon controls. These data suggest that magnetite reduction is coupled to carbon metabolism in S. putrefaciens. Bacterial reduction rates of magnetite are of the same order of magnitude as those estimated for reduction by sulfide. If such remobilization of magnetite occurs in nature, it could have a major impact on sediment magnetism and diagenesis.     

Extraction Efficiency of Hydrophilic and Lipophilic Antioxidants from Lyophilized Foods Using Pressurized Liquid Extraction and Manual Extraction

The efficient extraction of antioxidants from food samples is necessary in order to accurately measure their antioxidant capacities. α‐Tocopherol and gallic acid were spiked into samples of 5 lyophilized and pulverized vegetables and fruits (onion, cabbage, Satsuma mandarin orange, pumpkin, and spinach). The lipophilic and hydrophilic antioxidants in the samples were sequentially extracted with a mixed solvent of n‐hexane and dichloromethane, and then with acetic acid–acidified aqueous methanol. Duplicate samples were extracted: one set was extracted using an automated pressurized liquid extraction apparatus, and the other set was extracted manually. Spiked α‐tocopherol and gallic acid were recovered almost quantitatively in the extracted lipophilic and hydrophilic fractions, respectively, especially when pressurized liquid extraction was used. The expected increase in lipophilic oxygen radical absorbance capacity (L‐ORAC) due to spiking with α‐tocopherol, and the expected increase in 2,2‐diphenyl‐1‐picrylhydrazyl radical scavenging activities and total polyphenol content due to spiking with gallic acid, were all recovered in high yield. Relatively low recoveries, as reflected in the hydrophilic ORAC (H‐ORAC) value, were obtained following spiking with gallic acid, suggesting an interaction between gallic acid and endogenous antioxidants. The H‐ORAC values of gallic acid–spiked samples were almost the same as those of postadded (spiked) samples. These results clearly indicate that lipophilic and hydrophilic antioxidants are effectively extracted from lyophilized food, especially when pressurized liquid extraction is used.     

活性炭和仲丁醇对牛乳蛋白水解液的脱苦效果研究

比较活性炭和仲丁醇对牛乳蛋白水解液的脱苦效果,结果表明,活性炭的脱苦效果明显优于仲丁醇。活性炭的最佳使用条件为：添加量2.5%(m/V)、处理温度30℃、时间30min,经上述处理,水解液的苦味基本脱除,氮损失为25%。脱苦前后水解液中氨基酸组成的变化明显,脱苦后水解液中疏水性氨基酸损失较大。     

不同有机氮源对葡萄酒发酵的影响

分别使用酵母浸粉和混合氨基酸作为模拟葡萄汁（36 °Bx）的有机氮源发酵葡萄酒,以保证葡萄酒的正常发酵和最终产品品 质。 通过测定发酵过程中的二氧化碳生成量、还原糖、可同化氮、甘油和挥发性化合物含量变化,比较酵母浸粉和混合氨基酸对葡萄酒 品质的影响。 结果表明,使用酵母浸粉耗还原糖量为295.7 g/L,生成乙醇97.20 g/L、甘油26.50 g/L、乙酸1.08 g/L和乙酸乙酯46.05 mg/L, 与使用混合氨基酸相比,多消耗还原糖130.47 g/L,多生成乙醇46.14 g/L、甘油7.95 g/L和乙酸0.54 g/L,增幅分别为78.95%、90.38%、 42.84%和99.35%。 使用酵母浸粉比混合氨基酸的发酵程度大,速度快。 因此,可用适量酵母浸粉替代混合氨基酸作为葡萄酒发酵的 氮源补充。     

功能粘胶纤维的耐酸碱性

为定量了解新型功能粘胶的耐酸碱性能,为后续纺织印染加工和产品开发提供必要的参考,文章选取了两种典型的功能粘胶纤维:珍珠粘胶纤维和安芙丽阻燃粘胶纤维,采用不同浓度的氢氧化钠、醋酸溶液进行处理,并测试处理后纤维的断裂强度和断裂伸长率。结果表明,添加阻燃成分和珍珠粉的功能粘胶酸碱处理前后的强度和断裂伸长率均比常规粘胶小。当氢氧化钠浓度达到0.75 mol/L和醋酸浓度2.41 mol/L时,珍珠粘胶和安芙丽阻燃粘胶的强度和伸长率虽有较大损失,但仍有良好的强度和断裂伸长率,分别在1.71 cN/dtex和13.6%以上。     

混合办公废纸附聚-磁性法脱除胶粘物的研究

对混合办公废纸进行附聚-磁性法脱除胶粘物（DCS）的附聚实验,结果表明,在温度75℃、时间45min、pH值11、浆浓4%、附聚用量2%、磁铁矿用量0.1%的附聚条件下,达到废水中DCS2.374g/L、浆中DCS0.216g/L、纸浆白度89.6%ISO的附聚效果。     

吸湿对不同干制方式下枸杞粉活性成分及色泽变化的影响

探讨晒干、烘干和冻干对枸杞粉吸湿前后多糖、黄酮和类胡萝卜素含量的影响,并采用高效液相色谱法测定了3种干制方式对黄酮类和胡萝卜素类化合物的种类和含量的影响,研究吸湿前后的色泽变化。结果表明:相同干制方式下,枸杞粉吸湿后多糖和类胡萝卜素含量均显著降低(p<0.05);黄酮含量显著升高(p<0.05),其中阿魏酸、咖啡酸、对香豆酸含量减少,而槲皮素、芦丁含量增大;3种干制方式的枸杞粉吸湿后的L*、a*、b*值较吸湿前均显著降低(p<0.05)。不同干制方式下,冻干枸杞粉的多糖和类胡萝卜素含量均高于其他两种干制方式,而烘干枸杞粉黄酮含量最高;其色泽参数显示,吸湿前:烘干>晒干>冻干,吸湿后:冻干>烘干>晒干。综合而言,吸湿对不同干制方式下枸杞粉活性成分的保留及色泽均有不利影响。     

涂覆法制备导电屏蔽涤纶水刺法非织造布工艺初探

采用石墨粉作导电填料、水性聚丙烯酸酯作粘合剂自制一种导电涂料,利用涂覆法制备导电屏蔽涤纶水刺法非织造布。讨论了石墨粉质量分数、固化温度、固化时间对涤纶水刺法非织造布导电屏蔽效果的影响,通过表面电阻和屏蔽效能SE测试结果比较选取最佳工艺。结果表明:石墨粉质量分数为35%、固化温度为120℃并固化20min时具有较好的导电屏蔽效果。