纳米磁性微粒固定化脂肪氧合酶的制备及其酶活研究

采用纳米磁性四氧化三铁固定脂肪氧合酶,考察不同因素对游离酶和固定化脂肪氧合酶酶活的影响。结果表明:电镜观察微粒呈黑色短棒状粒子,固定在载体上酶的含量约为6.0%;游离酶与固定化脂肪氧合酶的最适温度均为30℃,游离酶最适p H为8.0,而固定化酶的最适p H为9.0,当双氧水的浓度分别达到14 g/L和8 g/L时,游离酶和固定化酶的活性分别达到最强;最适条件下,游离酶的酶活为3.95×105U/m L,固定化酶的酶活为9.40×105U/g。     

猪肉瘦肉精检测方法的比较与运用

20世纪80年代,美国科学家意外发现盐酸克伦特罗(俗称瘦肉精是一种兴奋剂)在提高猪肉瘦肉率上有较大效果,一度就有在饲料中添加一定量的盐酸克伦特罗的方法,并作为科研成果在生猪饲养中推广运用.     

Gelatin nanocomposite films incorporated with magnetic iron oxide nanoparticles for shelf life extension of grapes

Nanocomposite films were obtained by solution casting method from aqueous solution of bovine gelatin with addition of various concentrations of magnetic iron oxide (MIO) nanoparticles (NPs) (5, 10, 15, and 20% w/w of dry gelatin). The incorporation of MIO NPs improved the mechanical and physical properties of the nanocomposites. The increase in concentration of NPs up to 10% improved barrier and mechanical properties which slightly decreased after increasing the concentration beyond that limit due to particle agglomeration. The scanning electron microscopy and X-ray diffraction (XRD) were used to evaluate the morphology and crystalline structure of gelatin nanocomposite films, respectively. Gelatin nanocomposites with 20% w/w NPs exhibited the highest antimicrobial activity against Escherichia coli (7.1 ± 0.085 mm) and Staphylococcus aureus (8.22 ± 1.04 mm). Finally, the potential of gelatin/MIO nanocomposites as packaging material was evaluated to extend the shelf life of grapes. The gelatin/MIO nanocomposites can be used as a replacement to non-biodegradable packaging.     

磁性纳米材料的制备及其应用研究进展

纳米技术是近年来发展起来的一个覆盖面极广、多学科交叉的科学领域.而磁性纳米材料因其优异的磁学性能,也逐渐发挥出越来越大的作用.随着科学工作者在合成、应用领域的拓展逐渐深入,也使得纳米材料的外形、尺寸的控制日趋完善.文章综述磁性纳米材料的合成方法及其近年来在不同领域的应用状况.     

磁性纳米材料在食品组分分离和安全检测领域的研究进展

作为一种新型高分子材料,磁性纳米材料具有功能性微粒比表面积大、可进行表面修饰、可高度选择性结合目标物以及特殊的磁响应等特性,近年来在生物医学、食品、环境等领域受到了广泛的关注和应用。文章概述近年来国内外关于磁性纳米材料应用于食品组分分离,以及食品安全检测方面的研究进展,并展望其应用前景。     

瘦肉精对运动员生理功能的影响及其检测方法的研究进展

近年来,关于瘦肉精的安全事件频频发生,严重威胁着人们的身体健康,造成了极其恶劣的影响;一些运动员有意或无意的服用,影响了竞技体育的公平原则,引起了人们的高度警惕与重视。本文对瘦肉精的特性、药理作用及残留危害(特别对运动员)进行了介绍,并综述了各种检测方法,包括用于确证的大型仪器分析方法与现场快速检测的免疫分析方法等,分析其各自优缺点,以期人们对瘦肉精有更全面的认识。     

Studying the magnetic,antibacterial, and catalytic activity properties of DBD/iron oxide nanoparticle-treated cotton fabric

In this study, the cotton fabrics were modified with dielectric barrier discharge (DBD). Untreated and DBD-treated cotton fabrics were printed with magnetic nanoparticles (γ-Fe₂O₃ nanoparticles). Argon was used as the working gas. The crystal structure, morphology, and magnetic nature of printed fabrics were investigated by X-ray diffraction, Scanning Electron Microscopy, and vibrating-sample magnetometry (VSM). The catalytic activity of the treated samples for wastewater treatment was studied. The effect of γ-Fe₂O₃ nanoparticles on the antibacterial activity of DBD-treated cotton fabric was also investigated. The results showed that DBD-treated samples can absorb more nanoparticles than untreated samples. The antibacterial activity of the DBD/γ-Fe₂O_3-treated samples, which was analyzed by the bacteria counting test, was increased considerably.     

还原氧化石墨烯/四氧化三铁纳米复合物的应用研究进展

还原氧化石墨烯/四氧化三铁(RGO/Fe_3O_4)纳米复合物是一种新型的磁性纳米材料,集Fe_3O_4和RGO的优点于一体,具备高比表面积、高稳定性、超顺磁性等优越的机械、电、热、光学特性,充分展现其在理论研究以及实际应用方面的价值和潜力。本文对近几年RGO/Fe_3O_4磁性纳米复合物材料在磁性固相萃取、锂电子电池、传感器材料、电磁波吸收、催化剂、酶的固定化、药物传输以及磁控开关方面的应用研究进展进行了综述,重点综述了RGO/Fe_3O_4磁性纳米复合材料在磁性固相萃取方面的应用研究,分析对象包括染料、金属离子、农兽药、增塑剂、抗生素以及生物大分子,展现出其在分离富集领域的巨大应用潜力。最后,提出RGO/Fe_3O_4纳米复合材料在研究中存在的问题,并对该材料的研究发展方向进行了展望。     

"瘦肉精"残留的危害与检测方法分析

主要介绍了"瘦肉精"的来源、作用机理、危害和检测方法,并对其监管过程中存在的问题进行了总结,以使消费者了解"瘦肉精"的危害.     

新型磁性纳米载体的制备及其对溶菌酶吸附特性研究

采用超声辅助化学共沉淀法合成了功能性超顺磁性纳米颗粒（Fe3O4@CS-Na）;采用TEM对Fe3O4@CS-Na的形貌和粒径进行了表征,结果显示,Fe3O4@CS-Na的粒径大约在10¹5nm;此外,以Fe3O4@CS-Na纳米颗粒为载体,对水溶液中溶菌酶（Lyz）的吸附特性进行了研究,由于载体具有较小的粒径,30min即达到了吸附平衡;Fe3O4@CS-Na对Lyz的吸附符合Langmuir吸附等温模型,且载体在重复六次的吸附-解吸附过程中对Lyz的吸附容量没有明显地降低。Fe3O4@CS-Na纳米颗粒有望在Lyz的分离纯化和固定化中显示出广阔的应用前景。      

脂肪酶在磁性纳米粒子上固定化及其酶学性质研究

以Fe_3O_4纳米粒子为载体,碳化二亚胺为交联剂,共价结合制备固定化脂肪酶,探讨脂肪酶固定化影响因素,并对固定化脂肪酶性质进行研究;运用TEM测定其粒径,用FTIR检测脂肪酶—Fe_3O_4磁性纳米粒子耦联。结果表明,脂肪酶固定化适宜条件为:200 mg磁性纳米粒子,加入2 ml 2.5mg/mL脂肪酶磷酸盐缓冲液(0.1mol/L,pH7.5),在4℃超声分散45 min,固定化酶最适pH为7.0,最适温度为45℃,均与游离酶相似;与游离酶相比,该固定化脂肪酶热稳定性明显提高,并具有良好操作和存储稳定性。     

还原氧化石墨烯分子印迹传感器的研制及其在磺胺间甲氧嘧啶检测中的应用

目的 建立一种印迹电化学传感器快速测定磺胺间甲氧嘧啶的方法。方法 以磺胺间甲氧嘧啶为目标分子, 在弱碱性条件下, 利用多巴胺在还原氧化石墨烯(reduced grapheme oxide, rGO)修饰后的玻碳电极上自聚制得分子印迹聚合膜。采取循环伏安法和差分脉冲伏安法分别对印迹膜的传感性能进行综合研究。结果 在最佳的优化条件下, 磺胺间甲氧嘧啶在20~1600 nmol/L的浓度范围内与峰电流具有良好线性关系, 相关系数r2=0.9964, 检出限为6.7 nmol/L (S/N=3)。实际样品测定的加标回收率为92.4%~108.3%。结论 该方法准确、灵敏, 适合于实际样品中磺胺间甲氧嘧啶残留的测定。     

磁性纳米材料制备及其在传感器检测领域的应用

在外界磁场的驱动下, 磁性纳米材料能迅速完成对目标物的吸附及其与基质的分离。基于这点, 磁性纳米材料在吸附分离, 环境治理, 食品安全等方面已有较多应用, 并将有更大的应用前景。本文主要对磁性纳米材料的制备方法、富集分离、传感器检测3个方面的研究进展进行介绍。其中, 磁性纳米材料的制备方法包括固、液和气相合成法。富集分离方法介绍了磁性纳米材料对有机污染物的吸附分离, 例如微塑料; 对无机金属离子的吸附分离, 例如铬离子, 铅离子。在传感器检测方面主要介绍了磁性纳米材料在电化学传感器、生物传感器、光学传感器方面的应用。     

Honey major protein characterization and its application to adulteration detection

The major proteins in honey have different molecular weights depending upon the honeybee species. To confirm the origin of major honey proteins, honey protein produced by Apis cerana or Apis mellifera were purified and analyzed by MALDI-TOF. Two major proteins were identified as a major royal jelly protein 1. Although two major proteins shared primary structure, they showed different molecular weights of 56 and 59 kDa, respectively. To discriminate the honeybee species producing honey using SDS–PAGE, artificial marker proteins, 56 and 59 kDa, were produced from Escherichia coli. Two artificial marker proteins were co-electrophoresed with honey samples and the difference in molecular weight was readily distinguished by SDS–PAGE. Therefore, the measurement of major proteins in honey is a useful method to discriminate the honey that produced from different honeybee species.     

猪肝中盐酸克伦特罗的快速检测研究

针对猪肉制品中"瘦肉精"超标问题,对随机抽取市售猪肝应用竞争性酶联免疫法进行了测定,采用醇提法及冷热处理工艺并对猪肝中瘦肉精的残留量的影响进行研究。结果表明,采用70%浓度的甲醇,热处理30min的熟肉制品瘦肉精残留少,去除瘦肉精更彻底。     

纳米磁性液体及其在印刷中的应用

纳米磁性液体是纳米铁磁性微粒在表面活性剂的包覆下,稳定地分散在载液中而形成的一种胶体体系,同时具有磁性和流动性,因此具有许多独特的磁学、流动力学,光学和声学特性,在工业领域得到广泛的应用.文章概述了纳米磁性液体的组成、制备技术、基本特性、应用以及当前研究进展,着重阐述了纳米磁性液体在防伪印刷以及快速射流印刷中的应用前景.     

Microwave absorption characterization and wettability of magnetic nano iron oxide/recycled PET nanofibers web

This paper describes the microwave characterization and wettability of a uniform and light magnetic nanofibers web. Iron oxide nanoparticles/recycled poly (ethylene terephthalate) nanofibers web (Fe₃O₄ NPs/RPET NFs web) were fabricated from bath-sonication solution via electrospinning method. For environmental conservation and economic reasons, RPET instead of virgin material was used. After synthesizing magnetic Fe₃O₄ NPs with an average diameter of 35?nm by precipitation method using iron sulfate and sodium hydroxide, Fe₃O₄ NPs/RPET NFs web was made. The main objective of this work is to show how Fe₃O₄ NPs are able to significantly modify electromagnetic properties at X-band frequencies. Microwave characterization is based on the microwave scattering parameters measured in the X-band (8–12?GHz). Various characterization methods, including field emission-scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM), have been used to study morphologies, crystalline structure, magnetic, and wettability properties of NFs web. The saturation magnetization of the Fe₃O₄ NPs/RPET NFs web at a concentration of 5% was 2.79?emu/g. The mathematical model was estimated for magnetization, diameter and concentration by MathWorks Model Predictive Control Toolbax Software. The wettability, reflection coefficient, absorption coefficient, and EMI shielding of Fe₃O₄ NPs/RPET NFs web have been improved compared to RPET NFs web.     

纳米金在食品安全检测中的应用研究进展

纳米金具有良好的生物相容性和独特的光学性质,可与生物和有机分子结合,形成功能化的纳米金。基于这些特性,纳米金在食品安全检测方面有着广泛的应用。本文综述了纳米金在食源性致病菌、生物毒素、重金属离子、药物残留、食品添加剂及非法添加物和其他食品有害因子检测中的应用实例,并对纳米金在食品安全检测方面的应用进行了展望。     

生物传感器在食源性致病菌检测中的应用

目前传统的检测食源性致病菌的方法主要依赖培养基对存活的细胞进行选择分离和传代,虽然这种方法很有效,但其检测周期长、程序复杂等缺点已经不能满足现代检测的要求。随着科学技术不断发展,特别是免疫学、生物化学、分子生物学的不断发展,人们已经建立了不少快速、简便、特异、敏感、低耗的检测技术。本文对应用生物传感器对食源性致病菌检测方法的发展及其前景进行了综述。      

Abiotic degradation of pentachloronitrobenzene by Fe(III): reactions on goethite and iron oxide nanoparticles

Pentachloronitrobenzene is a fungicide that is degraded in anoxic soils and sediments through unknown processes that are often thought to be biologically mediated. The present research describes the kinetics for the abiotic reduction of this compound in aqueous Fe(II)/goethite systems at near-neutral pH values. The results provide evidence for a rate-affecting surface-association process rather than a direct (i.e., kinetically second-order) reaction with an adsorbed Fe(II) species. It is therefore likely that the iron oxide surface participates directly in the reaction. Furthermore, reduction is observed in the apparent presence of trace amounts of suspended iron oxide nanoparticles, formed in situ by the oxidation of Fe(II). Given that Fe(III) colloids and other nanoscale phases may occur in natural sediments, such abiotic reactions could significantly influence the environmental fate of nitroaromatic compounds.