Monodisperse FePt nanoparticles and ferromagnetic FePt nanocrystal superlattices

Synthesis of monodisperse iron-platinum (FePt) nanoparticles by reduction of platinum acetylacetonate and decomposition of iron pentacarbonyl in the presence of oleic acid and oleyl amine stabilizers is reported. The FePt particle composition is readily controlled, and the size is tunable from 3- to 10-nanometer diameter with a standard deviation of less than 5%. These nanoparticles self-assemble into three-dimensional superlattices. Thermal annealing converts the internal particle structure from a chemically disordered face-centered cubic phase to the chemically ordered face-centered tetragonal phase and transforms the nanoparticle superlattices into ferromagnetic nanocrystal assemblies. These assemblies are chemically and mechanically robust and can support high-density magnetization reversal transitions.     

氧化铁纳米粒子对玉米生理效应影响的研究

为了有效地评估纳米粒子对植物潜在的生物毒性,选取玉米和氧化铁纳米粒子为研究对象,探讨氧化铁纳米粒子（nailo-Fe2O3）对玉米生理效应的影响。同时,测定抗氧化酶体系的酶活性和丙二醛（MDA）含量,结果表明当受到氧化铁纳米粒子胁迫时,玉米会发生氧化应激反应,但这会激发玉米本身的保护机制,导致整个机体的抗氧化预防能力增强,使得机体的超氧阴离子自由基含量降低,减少对机体的损害。同时,通过玉米根的荧光切片和透射电镜切片,可以得出氧化铁纳米粒子从上皮层运输到皮质层主要是通过质外体途径．并且能够进入玉米细胞中、、这些为评估纳米粒子对植物的影响奠定基础。     

超声辅助磁性纳米四氧化三铁催化过氧化氢降解亚甲蓝染料的研

建立了一种基于超声辅助磁性四氧化三铁纳米微粒催化过氧化氢降解亚甲蓝染料的方法,研究了四氧化三铁纳米微粒浓度、过氧化氢浓度、pH值、反应时间、超声时间和温度等对催化降解反应的影响.结果表明,当四氧化三铁纳米粒子浓度为600mg/L,过氧化氢浓度为0.32mol/L,pH值为5,超声时间为3min,温度为30℃,反应时间为2h时,模拟染料废水中亚甲蓝的去除率最高可达到95%.     

巯基修饰和胡敏酸包裹纳米Fe3O4颗粒的制备及其对溶液中Pb2+ Cd2+ Cu2+的吸附效果研究

采用改进的化学共沉淀法制备纳米Fe3O4颗粒,利用3-巯丙基三乙氧基硅烷(MPTES)和胡敏酸(HA)对所制备的纳米Fe3O4进行巯基修饰和胡敏酸包裹,通过红外光谱(IR)、X射线衍射分析(XRD)等方法对上述制备的纳米颗粒的性质进行了表征,同时对上述不同的纳米Fe3O4颗粒在恒温下对水体中金属离子(Pb2+、Cd2+、Cu2+)的吸附进行了研究。结果表明,所制备的功能化前后的纳米Fe3O4纯度较高,平均粒径约为20～30nm,且分布均匀。不同纳米型Fe3O4颗粒对溶液中金属离子具有较好的吸附性能,其吸附等温线均可以用Langmuir方程进行较好的拟合;裸露的纳米Fe3O4颗粒对Pb2+最大吸附量(b)达到172.4mg·g-1,经过胡敏酸包裹后的纳米Fe3O4颗粒对Cd2+、Cu2+的最大吸附量分别增加了75.8%和231.5%;对不同金属离子而言,裸露的和巯基修饰的纳米Fe3O4对3种重金属离子的吸附能力的强弱为Pb2+>Cd2+>Cu2+,而经胡敏酸包裹后的顺序则为Pb2+>Cu2+>Cd2+;与裸露的和巯基修饰的纳米Fe3O4相比,经HA包裹的纳米Fe3O4对Cd2+和Cu2+具有较高的吸附量和吸附亲...     

Fe3 O4／TiO2复合物的制备

[目的]以钛铁矿为原料,制备包覆性Fe_3O_4/TiO_2磁性光催化剂。[方法]研究不同温度、反应时间、钛铁矿颗粒大小、是否冷凝回流等条件下钛铁矿的溶解情况以及TiO_2、Fe_3O_4/TiO_2的产率和催化效果,并采用X射线粉末衍射仪(XRD)、红外光谱(FT-IR)、扫描电镜(SEM)、透射电镜(TEM)等对催化剂产物进行表征,且验证催化剂的磁性能。[结果]该方法可以制备出磁性良好、包覆效果好、较纯净的Fe_3O_4/TiO_2包覆性光催化材料。[结论]制备出的Fe_3O_4/TiO_2复合物保持了Fe_3O_4的磁性,是一种性能优良的包覆性光催化材料。     

磁性Fe3O4纳米粒子在农学领域应用研究进展

磁性Fe3O4纳米粒子由于体积小、比表面积大、具有表面效应和超顺磁性等优良特性在农学相关领域得到了广泛的应用。综述了磁性Fe3O4纳米粒子在磁性固相萃取、食品工业、控释农药、农药增效及光催化降解等农学相关领域的应用,比较了磁性Fe3O4纳米粒子不同制备方法的优缺点,探讨了磁性Fe3O4纳米粒子在应用中存在的挑战和未来的发展趋势。     

Bacterial Methanogenesis and Growth from CO2 with Elemental Iron as the Sole Source of Electrons

Previous studies of anaerobic biocorrosion have suggested that microbial sulfur and phosphorus products as well as cathodic hydrogen consumption may accelerate anaerobic metal oxidation. Methanogenic bacteria, which normally use molecular hydrogen (H(2)) and carbon dioxide (CO(2)) to produce methane (CH(4)) and which are major inhabitants of most anaerobic ecosystems, use either pure elemental iron (Fe(0)) or iron in mild steel as a source of electrons in the reduction of CO(2) to CH(4). These bacteria use Fe(0) oxidation for energy generation and growth. The mechanism of Fe(0) oxidation is cathodic depolarization, in which electrons from Fe(0) and H(+) from water produce H(2), which is then released for use by the methanogens; thermodynamic calculations show that significant Fe(0) oxidation will not occur in the absence of H(2) consumption by the methanogens. The data suggest that methanogens can be significant contributors to the corrosion of iron-containing materials in anaerobic environments.     

Topographic and magnetic-sensitive scanning tunneling microscope study of magnetite

The topographic and magnetic surface structure of a natural single crystal of magnetite (Fe(3)0(4)), a common mineral, has been studied from the submicrometer scale down to the atomic scale with a scanning tunneling microscope having nonmagnetic tungsten as well as ferromagnetic iron probe tips. Several different (001) crystal planes were imaged to atomic resolution with both kinds of tips. A selective imaging of the octahedrally coordinated Fe B-sites in the Fe-O planes, and even a selective imaging of the different magnetic ions Fe(2+) and Fe(3+), has been achieved, demonstrating for the first time that magnetic imaging can be realized at the atomic level.     

磁性超晶格中静磁波的表面退磁效应

利用等效介质理论，在考虑磁性层表面动力学退磁场影响的前提下，首先给出了动力学磁化率，然后求出了色散方程。当坐标系的，轴垂直于层间界面，饱和磁化和外场均沿z轴方向时，数值计算结果表明：表面静磁波可以在任意磁性层的相对厚度时存在，同时表面波的传播方向处在x-z平面的第三和第四象限中。这两结论与以往的结果不同。体静磁模频率的连续区在表面模频率的上方。     

柠檬酸对纳米氧化铁诱导水稻根表铁膜形成及对水稻铁吸收转运的影响

本研究利用水培模拟实验探讨了柠檬酸对纳米氧化铁(NPs,γFe_2O_3)诱导水稻根表铁膜的影响,同时研究了其对铁(Fe)在植株体内吸收转运的影响。结果表明,低浓度柠檬酸包被和未包被处理NPs能够显著增加水稻根生物量,但对水稻地上部生物量影响不显著。NPs能够诱导根表铁膜形成,然而铁膜量随着柠檬酸浓度增加而下降,可能是由于柠檬酸降低NPs的Fe2+释放量造成的;但是2.10 mg·L~(-1)柠檬酸包被NPs能显著提高根表铁膜量。根表铁膜主要以无定型为主(除柠檬酸包被处理外),晶格态仅占铁膜总量的24.88%~48.12%;其中,由于根表铁膜的晶格构造与NPs类似,可能晶格态铁膜主要来源于NPs的直接吸附沉淀。柠檬酸的加入显著降低Fe在根表和根中累积,但是增加了Fe在地上部的累积;然而,柠檬酸包被NPs处理能够增加Fe在根表和植株地上部的累积,但降低Fe在根系中的累积。2.10 mg·L~(-1)柠檬酸(包被和未包被NPs处理)能够减弱Fe从根表向根内的转移,但是增强了Fe从根向地上部的转移。不同NPs处理条件下,Fe在水稻植株不同部位均存在富集现象,根表和地上部的富集系数显著高于根内。     

Radio-wave heating of iron oxide nanoparticles can regulate plasma glucose in mice

Medical applications of nanotechnology typically focus on drug delivery and biosensors. Here, we combine nanotechnology and bioengineering to demonstrate that nanoparticles can be used to remotely regulate protein production in vivo. We decorated a modified temperature-sensitive channel, TRPV1, with antibody-coated iron oxide nanoparticles that are heated in a low-frequency magnetic field. When local temperature rises, TRPV1 gates calcium to stimulate synthesis and release of bioengineered insulin driven by a Ca(2+)-sensitive promoter. Studying tumor xenografts expressing the bioengineered insulin gene, we show that exposure to radio waves stimulates insulin release from the tumors and lowers blood glucose in mice. We further show that cells can be engineered to synthesize genetically encoded ferritin nanoparticles and inducibly release insulin. These approaches provide a platform for using nanotechnology to activate cells.     

沸石-纳米零价铁的制备及其对溶液中Cu2+的吸附研究

采用液相还原法制备沸石-纳米零价铁复合材料,并通过添加不同质量的沸石得到不同铁与沸石比例的沸石-纳米零价铁复合材料(Z-nZVI),考查了不同比例复合材料对Cu~(2+)的吸附效果,确定最佳铁与沸石比例为1∶6,并对该比例材料、纳米零价铁与沸石进行了性状表征(包括:TEM、XRD及BET)。该比例复合材料对Cu~(2+)的吸附动力学实验结果表明,其吸附平衡时间约为1 h;动力学方程拟合结果表明,该材料的动力学过程更符合准二级动力学方程,且平衡吸附量达到515.46 mg·g~(-1)Fe0;对等温吸附实验数据进行Langmuir和Freundlich拟合结果表明,Langmuir方程更适用于描述沸石-纳米零价铁对Cu~(2+)的吸附。比较而言,沸石-纳米零价铁(1∶6)对于Cu~(2+)的吸附效果要优于纳米零价铁并远高于沸石。三因素三水平正交试验(溶液温度:25、35、45℃;pH:3、4、5;ZnZVI添加量:0.1、0.14、0.21 g·40 m L~(-1))结果表明,铁沸石比为1∶6的沸石-纳米零价铁对Cu~(2+)的最优吸附条件为:温度45℃,pH 3,Z-nZVI添加量0.21 g·40 m L~(-1)。上述结果表明沸石-纳米零价铁可应用于水体中Cu~(2+)的去除。     

磁性纳米颗粒在DNA分离纯化中的应用

为了解磁性纳米颗粒在DNA分离纯化中的应用,采用文献综述和归纳总结的方法,阐述了1997—2021年以铁氧化物为核心的磁性纳米材料的研究进展,同时比较了材料结构和表面相关活性官能团的修饰对DNA提取效率的影响。结果表明：1）应用磁性纳米颗粒的固相萃取有着安全无毒、操作简单、可重复使用、能够实现自动化与高通量操作等多种优势,提取DNA效率相比于商业化试剂盒也有优势。2）目前磁性纳米材料已有比较全面的研究。磁性纳米颗粒的尺寸、孔径大小、磁化强度及引入的活性官能团不同等性质均对DNA的提取效率有影响,改变这些性质研发新型且高效的功能化磁性纳米颗粒或改变磁性纳米材料的制备方法、所提取DNA的形态性质、溶液的pH或盐浓度等试验条件,以提高DNA与材料的解吸率,不断优化磁性分离过程,提高DNA分离效率和质量。3）发展高通量商业化的核酸提取程序,是磁性固相萃取可观的发展前景。4）磁性纳米颗粒除了在核酸提取中的应用,在其他生物医学应用中也有着广泛的研究。以上结果均表明磁性纳米材料有着极强的研究发展前景。     

Spontaneous superlattice formation in nanorods through partial cation exchange

Lattice-mismatch strains are widely known to control nanoscale pattern formation in heteroepitaxy, but such effects have not been exploited in colloidal nanocrystal growth. We demonstrate a colloidal route to synthesizing CdS-Ag(2)S nanorod superlattices through partial cation exchange. Strain induces the spontaneous formation of periodic structures. Ab initio calculations of the interfacial energy and modeling of strain energies show that these forces drive the self-organization of the superlattices. The nanorod superlattices exhibit high stability against ripening and phase mixing. These materials are tunable near-infrared emitters with potential applications as nanometer-scale optoelectronic devices.     

High-Temperature XAS Study of Fe2SiO4 Liquid: Reduced Coordination of Ferrous Iron

X-ray absorption spectroscopy (XAS) of Fe(2+) in Fe(2)SiO(4) liquid at 1575 kelvin and 10(-4) gigapascal (1 bar) shows that the Fe(2+) -O bond length is 1.98 +/- 0.02 angstroms compared with approximately 2.22 angstroms in crystalline Fe(2)SiO(4) (fayalite) at the melting point (1478 kelvin), which indicates a decrease in average Fe(2+) coordination number from six in fayalite to four in the liquid. Anharmonicity in the liquid was accounted for using a data analysis procedure. This reduction in coordination number is similar to that observed on the melting of certain ionic salts. These results are used to develop a model of the medium-range structural environment of Fe(2+) in olivine-composition melts, which helps explain some of the properties of Fe(2)SiO(4) liquid, including density, viscosity, and the partitioning of iron and nickel between silicate melts and crystalline olivines. Some of the implications of this model for silicate melts in the Earth's crust and mantle are discussed.     

The Exclusion of D2O from the Hydration Sphere of FeSO4{middle dot} 7H2O Oxidized by Thiobacillus ferrooxidans

Infrared spectra demonstrate that neither FeSO(4) . 7H(2)O nor its bacterial or abiotic hydrated oxidation products incorporate deuterium in acid D(2)O solutions. Deuterium exchange occurred as bridging OD when bacterially oxidized iron was precipitated from D(2)O solutions as ferric hydroxysulfates. The exclusion of deuterium depended upon the stabilization of aquated Fe(II) and Fe(III) complexes by sulfate ions in outer-sphere coordination and is consistent with the requirement and postulated role of sulfate in iron oxidation by Thiobacillus ferrooxidans.     

干湿交替条件下铁氧化对水稻土CO_2排放的影响

以湖北省2种典型水稻土[咸宁市的中稻-冬闲水稻土(第四世纪红壤,XR)和潜江市的中稻-冬闲水稻土(钙质潮土,QR)]为材料,研究土壤干湿交替条件下[土壤落干(孔隙含水率55%)到完全淹水(土水比1∶1)]添加Fe2+对土壤Fe3+、可溶性有机碳(DOC)含量及CO2排放的影响,拟揭示水分转变过程中土壤活性铁氧化对土壤有机碳固持的影响。结果表明,整个培养期间,与CK(不添加Fe2+)相比,添加Fe2+促进了XR和QR土壤中活性铁的氧化,XR和QR土壤中Fe3+平均含量分别较CK提高了133.87%和95.66%。落干期间,与CK相比,添加Fe2+促进了CO2的排放,XR和QR土壤CO2累积排放量分别增加了59.77%和124.48%;促进了土壤DOC的积累,XR和QR土壤DOC平均含量分别提高了42.57%和23.71%。淹水期间,与CK相比,添加Fe2+抑制了CO2的排放,XR和QR土壤CO2累积排放量分别降低了54.03%和35.27%;培养前期促进了土壤DOC的积累,培养后期抑制了土壤DOC含量的积累,总体上XR土壤DOC平均含量降低了35.29%,QR土壤DOC含量提高了16.59%。整个培养期间,添加Fe2+后,XR和QR土壤CO2累积排放量分别降低了43.87%和22.14%。综上,我国南方富含铁氧化物的红壤具有更高的固碳减排潜力。     

硅烷化氨基磁性粒子的制备及其固定化木瓜蛋白酶的研究

通过硅烷化试剂(3-氨基丙基三乙氧基硅烷)对SiO2包覆的Fe3O4磁性纳米粒子进行表面修饰,得到了一种高亲水性、粒度均匀、表面富含氨基的磁性复合粒子,并以木瓜蛋白酶为模式酶,探讨了木瓜蛋白酶的最佳固定化条件,研究了固定化木瓜蛋白酶的酶学性质和动力学参数。结果表明:当戊二醛浓度在5%,固定化时间为4h,给酶量为10mg/g时,固定化酶的酶活最高;固定化酶的最适反应温度为70℃,最适反应pH值为6.8,Km值为34.48mg/mL,酶活回收率为46.5%。固定化酶在热稳定性和pH稳定性上较游离酶均得到了一定的提高。     

Fe3O4纳米颗粒细胞毒性的研究

为了研究Fe3O4纳米颗粒在突变细胞系的中的毒性问题，采用不同浓度Fe3O4纳米颗粒处理含有核苷酸剪切修复基因XPF突变的原代XPF细胞与HeLa细胞.细胞集落形成实验证实了Fe3O4纳米颗粒对XPF细胞的生长有显著的抑制作用，表现出了一定的细胞毒性，说明Fe3O4纳米颗粒不适合应用于有核苷酸剪切修复基因突变的人群.RT-PCR的结果发现CHEK1，RPA1，RPA2和RPA3的转录在XPF细胞内较明显地增加，说明了Fe3O4纳米颗粒通过改变XPF细胞内这些基因的转录，从而抑制其分裂和生长.     

Iron-Containing Cells in the Honey Bee (Apis mellifera)

Honey bees are sensitive to earth strength magnetic fields and are reported to contain magnetite (Fe3O4) in their abdomens. We report bands of cells around each abdominal segment that contain numerous electron-opaque, iron-containing granules. The iron is principally in the form of hydrous iron oxides.