“All‐in‐One” Nanoparticles for Trimodality Imaging‐Guided Intracellular Photo‐magnetic Hyperthermia Therapy under Intravenous Administration

Great efforts have been devoted so far to combine nano‐magnetic hyperthermia and nano‐photothermal therapy to achieve encouraging additive therapeutic performance in vitro and in vivo with limitation to direct intratumoral injection and no guidance of multimodality molecular imaging. In this study, a novel multifunctional theranostic nanoplatform (MNP@PES‐Cy7/2‐DG) consisting of magnetic nanoparticles (MNPs), poly(3,4‐ethylenedioxythiophene):poly(4‐styrenesulfonate) (PES), Cyanine7 (Cy7), and 2‐deoxyglucose (2‐DG)‐polyethylene glycol is developed. They are then applied to combined photo‐magnetic hyperthermia therapy under intravenous administration that is simultaneously guided by trimodality molecular imaging. Remarkably, nanoparticles are found aggregated mainly in the cytoplasm of tumor cells in vitro and in vivo, and exhibit stealth‐like behavior with a long second‐phase blood circulation half‐life of 20.38 ± 4.18 h. Under the guidance of photoacoustic/near‐infrared fluorescence/magnetic resonance trimodality imaging, tumors can be completely eliminated under intracellular photo‐magnetic hyperthermia therapy with additive therapeutic effect due to precise hyperthermia. This study may promote a further exploration of such a platform for clinical applications.     

Orientation Mediated Enhancement on Magnetic Hyperthermia of Fe3O4 Nanodisc

A two‐step chemical approach to synthesize high quality Fe₃O₄ nanodisc is reported. The magnetic hyperthermia properties of the nanodisc and isotropic nanoparticles are investigated systematically. The results suggest that the nanodisc shows much higher specific absorption rate (SAR) than isotropic nanoparticles. This is attributed to the parallel alignment of nanodisc with respect to the alternating current magnetic field, which is confirmed by good agreement between experimental results and micromagnetic simulation. It is found that such parallel alignment could enhance the SAR value by a factor of ≈2 with respect to the randomly oriented case. The above results indicate that the nanodisc provides an excellent thermal seed for magnetic hyperthermia. This study sheds the light on the magnetic hyperthermia mechanism of magnetic nanodisc and it also opens the window to explore high efficiency thermal seeds by controlling the orientation of magnetic nanostructures.     

Mussel‐Inspired Electrospun Smart Magnetic Nanofibers for Hyperthermic Chemotherapy

A method for the versatile synthesis of novel, mussel‐inspired, electrospun nanofibers with catechol moieties is reported. These mussel‐inspired nanofibers are used to bind iron oxide nanoparticles (IONPs) and the borate‐containing anticancer drug Bortezomib (BTZ) through a catechol metal binding mechanism adapted from nature. These smart nanofibers exhibit a unique conjugation of Bortezomib to their 1, 2‐benzenediol (catechol) moieties for enabling a pH‐dependent drug delivery towards the cancer cells and the IONPs via strong coordination bonds for exploiting the repeated application of hyperthermia. Thus the synergistic anticancer effect of these mussel‐inspired magnetic nanofibers were tested in vitro for the repeated application of hyperthermia along with the chemotherapy and found that the drug‐bound catecholic magnetic nanofibers exhibited excellent therapeutic efficacy for potential anticancer treatment.     

Magnetic properties of nickel filament polymer-matrix composites

The magnetic properties of polyethersulfone-matrix composites with 3-19 vol.% polycrystalline nickel filaments (0.4 (im diam) were investigated. These filaments were found to exhibit hysteresis energy loss 10800 J/m³ of nickel and coercive force 16.9 kA/m, compared to corresponding values of 4930 J/m³ and 4.7 kA/m for 2 μ.m diam polycrystalline nickel fibers, 1020 J/m³ and 0.5 kA/m for 20 μm diam polycrystalline nickel fibers, and 1280 J/m³ and 2.3 kA/m for solid polycrystalline nickel.     

废旧镍氢电池溶胶–凝胶法制备Ni_(0.5)Co_(0.5)Fe_2O_4的研究

以硫酸溶解废旧镍氢电池所得溶液为原料,采用溶胶–凝胶法制备出纳米晶镍钴铁氧体。借助于XRD、TG和VSM对产品的相结构和磁性能进行研究,并进一步探讨制备过程中的影响因素。结果表明,溶胶–凝胶法制备镍钴铁氧体的适宜条件为:柠檬酸与金属离子总量的摩尔比1:1,溶液的pH值7.0,煅烧温度850℃,煅烧时间3 h。该条件下所制得产品的剩余磁化强度为13.635 A.m2/kg,矫顽力为32.5 kA/m,饱和磁化强度为50.713 A.m2/kg。     

Low-threshold 1.3-μm InGaAsN:Sb-GaAs single-quantum-well lasersgrown by molecular beam epitaxy

1.3-μm InGaAsN:Sb-GaAs single-quantum-well laser diodes have been grown by a solid source molecular beam epitaxy (MBE) using Sb as a surfactant. A record low threshold of 1.02 kA/cm² and a slope efficiency of 0.12 W/A are obtained for broad-area laser diodes under pulsed operation at room temperature. A characteristic temperature of 64 K and a lasing wavelength temperature dependence of 0.38 nm/°C are reported     

Mn在HDDR各向异性NdFeCoB磁粉中的作用

采用HDDR(氢化–歧化–脱氢–再复合)技术制备NdFeCoB合金磁各向异性磁粉。研究了元素Mn对NdFeCoB合金HDDR磁粉的磁性能和磁各向异性的影响。结果表明:加入x(Mn)为2%以下的Mn元素没有改变NdFeCoB合金的相组成,但可提高NdFeCoB合金各相在氢气中的稳定性:当加入x(Mn)从0增加到2%时,NdFeCoB磁粉的内禀矫顽力Hcj从700 kA/m降低到450 kA/m,而NdFeCoB磁粉的磁各向异性DOA值从0.22增加到0.45。     

低热固相–溶胶凝胶法制备钴铁氧体的研究

为了改善CoFe2O4的磁性能,以柠檬酸、硝酸钴、硝酸铁为原料,用低热固相反应与sol-gel法相结合,制备了CoFe2O4晶体(样品)。借助于热分析、XRD、SEM和振动样品磁强计(VSM)等测试手段,考察了低热固相反应过程、煅烧温度和煅烧时间对样品结构及磁性能的影响。结果表明:在700℃煅烧2.0 h所得样品的平均晶粒径小(34.17 nm),分散均匀,磁性能好,其饱和磁化强度Ms为75.83 A.m2/kg,矫顽力Hc为127.201 kA/m。     

Large‐Scale Synthesis,Annealing, Purification,and Magnetic Properties of Crystalline Helical Carbon Nanotubes with Symmetrical Structures

Crystalline helical carbon nanotubes (HCNTs) are synthesized as the main products in the pyrolysis of acetylene at 450 °C over Fe nanoparticles generated by means of a combined sol–gel/reduction method. Transmission electron microscopy (TEM) images reveal that there are two HCNTs attached to each Fe₃C nanoparticle, and that the two HCNTs are mirror images of each other. Annealing in Ar at 750 °C and purification by immersion in hot (90 °C) HCl solution do not significantly change the structure of the HCNTs, despite the partial removal of Fe nanoparticles by the latter treatment. The magnetic properties of the as‐prepared, annealed, and purified HCNTs have been systematically examined. The annealed sample shows relatively high magnetization due to the ferromagnetic α‐Fe nanoparticles encapsulated in the HCNT nodes. In the case of HCl treatment, relatively pure HCNTs are obtained by the removal of ferromagnetic nanoparticles from the double‐HCNT nodes. The effects of the amount of catalyst used in the synthesis process on the morphology and yield of the carbon products have also been investigated.     

超细Co/Cu纳米多层膜磁性研究

利用磁控溅射方法制备了纳米Co/Cu多层膜。利用扫描探针显微镜(SPM)观测了其表面形貌和磁畴结构,并通过振动样品磁强计(VSM)测量了磁性。结果表明,薄膜的微结构和磁性随非磁性层厚度的变化有着非常显著的变化。超细Co颗粒构造的多层膜样品,颗粒尺寸逐渐增大,磁畴尺寸先减小后增大,最后发生明显的聚集。磁性金属和非磁性金属的比例对多层膜之间的交换耦合相互作用有显著影响。平行膜面方向上的饱和场明显小于垂直膜面方向。当体积比约为1∶80时,平行膜面方向饱和场为95.9 kA/m,垂直方向饱和场为328.1 kA/m。此时两个方向上的饱和场、剩磁、矫顽力和磁滞损耗均为最小值。     

An experimental study on improvement of performance for hemispherically shaped high-power IRED's with Ga1-xAlxAs grown junctions

This paper describes the structure and performance of a high-power infrared emitting diode (IRED) designed as a high speed optical beam source for optoelectronic applications. The heterostructured junction is formed on a thick Ga1-xAlxAs liquid phase epitaxy (LPE) grown layer which is used to shape hemispherical emitting surfaces. Dislocation density in recombination region was considerably decreased by the thick layer growth on a GaAs wafer used as a primary substrate. Under dc operations, external quantum efficiencies of around 45 percent at a current density of 0.6 kA/cm²and about 110 mW of optical output power at 200 mA (1 kA/cm²) have been obtained from the diodes with a 160-µm junction diameter. The tendency to reach power saturation with increased current has been decreased by means of reducing of thermal resistance of the mount, and the diodes with 240- µm junction diameter have shown about 180 mW at 600 mA dc and 1.4 W at a 4-A pulse (60 Hz, 50 µs). A large improvement in high frequency response has been obtained and the bandwidth at -3-dB intensity has reached above 120 MHz.     

铁基非晶软磁合金的制备及磁性能研究

研究了铁基非晶(Fe1–xCox)78.4Nb2.6Si9.0B9.0Cu1.0(x=0,0.15,0.35,0.55或0.75)软磁合金的制备工艺及磁性能。结果表明:采用熔体快淬法制备的非晶薄带宽约3mm,厚20～40μm;最佳工艺参数为铜轮转速35m/s,熔体射流压力0.14MPa;借XRD分析了合金的相结构,发现合金薄带为非晶态;通过振动样品磁强计(VSM)测量了磁性能,其Bs大于1.00T,Hc为2.31～5.17kA/m。用畴壁钉扎效应分析了Hc偏高的原因。     

Nb添加对Fe-Y-B合金非晶形成能力和磁性能的影响

利用单辊快淬法制备了Fe74Y6-xNbxB20(x=0,1,2,3,4)非晶合金条带,利用XRD、HRTEM、DTA和VSM对样品的结构、非晶形成能力和磁性能等进行了测试。结果表明:Fe74Y6–xNbxB20(x=1,2,3,4)合金系的饱和磁化强度Ms>104 A.m2/kg,矫顽力Hc<1.59 kA/m,显示出良好的软磁性能。添加微量Nb扩大了非晶合金的过冷液相区,当Nb含量为摩尔分数1%时,过冷液相区Tx=63℃,此时合金具有最大的非晶形成能力,同时具有最大的饱和磁化强度(Ms=133 A.m2/kg)和最低的矫顽力(Hc=1.27 kA/m)。     

球磨与共沉淀法制备MnZn铁氧体的对比研究

分别采用高能球磨和化学共沉淀法制备了MnZn铁氧体,通过XRD、VSM和金相显微镜的分析,对两种铁氧体的预烧料粉末、烧结体的显微结构以及磁性能做了比较。结果表明:化学共沉淀法所制备的预烧料粉末具有晶粒细小、均匀和活性高等优点;与高能球磨法相比,化学共沉淀法烧结磁体的密度较高、晶粒尺寸较大,磁性能更为优良。其相应的磁性能参数Ms、Mr、Hc和μi分别为3.845×102kA/m,3.421kA/m,0.722kA/m和5500。     

Multianchored Glycoconjugate‐Functionalized Magnetic Nanoparticles: A Tool for Selective Killing of Targeted Bacteria via Alternating Magnetic Fields

New technologies that do not rely on antibiotics are urgently needed to treat bacterial infections caused by multidrug‐resistant bacteria. Herein, the feasibility of using alternating magnetic field (AMF) to selectively kill enterotoxigenic Escherichia coli strain K99 (EC K99) in the presence of multianchored glycoconjugate‐functionalized magnetic nanoparticles is explored. Poly(ethylene oxide)‐poly(acrylic acid)‐dopamine functionalized magnetic nanoparticles (PEO‐MNPs) are synthesized and functionalized with bacteria‐specific glycoconjugate Neu5Ac(α2‐3)‐Gal‐(β1‐4)Glcβ‐sp (GM3‐MNPs) for specific adherence to EC K99. When such mixtures are exposed to an alternate magnetic field (31 kA m^?1, 207 KHz), an ≈3‐log reduction in colony forming units of EC K99 is achieved in 120 min. Moreover, in a mixed‐bacterial culture environment, targeted killing of EC K99 is achieved with minimal damage to nontargeted bacterium. Electron microscopy images along with live/dead staining assays demonstrate visible membrane damage of EC K99 cells in the presence of GM3‐MNPs and AMF. Additionally, intracellular adenosine triphosphate (ATP) levels of EC K99 are significantly diminished in the presence of GM3‐MNPs and AMF. These results suggest that specific glycoconjugate‐functionalized magnetic nanoparticles when mediated by AMF can be potentially used as a novel nonantibiotic treatment platform to inactivate/kill targeted bacterial pathogens, with minimal impact on normal microflora and the affected body region/tissue.     

铁磁性微晶玻璃的制备

采用熔融法制备了SiO_2-Na_2O-CaO-P_2O_5-Fe_2O_3系微晶玻璃。制备过程中磁铁矿晶相在玻璃自然冷却时自然析出,故不需要对玻璃进行核化和晶化等热处理。利用XRD确定了样品晶相组成并计算了样品中晶体的晶格常数和晶粒度,采用振动样品磁强计(VSM)测试了样品的磁性能。结果表明:所制微晶玻璃只含有磁铁矿晶相并具有生物活性;Fe_2O_3质量分数为45%的样品性能最佳,其比饱和磁矩为20.24A·m~2/kg,内禀矫顽力H_(cj)为7kA/m。     

High-performance long-wavelength (λ~1.3 μm) InGaAsPNquantum-well lasers

We demonstrate high-performance InGaAsPN quantum well based long-wavelength lasers grown on GaAs substrates, nitrogen containing lasers emitting in the λ=1.2- to 1.3-μm wavelength range were grown by gas source molecular beam epitaxy using a RF plasma nitrogen source. Under pulsed excitation, lasers emitting at λ=1.295 μm exhibited a record low threshold current density (J_TH) of 2. 5 kA/cm². Lasers grown with less nitrogen in the quantum well exhibited significantly lower threshold current densities of J_TH =1.9 kA/cm² at λ=1.27 μm and J_TH=1.27 kA/cm² at λ=1.2 μm. We also report a slope efficiency of 0.4 W/A and an output power of 450 mW under pulsed operation for nitrogen containing lasers emitting at 1.2 μm     

NdFeB磁粉对粘结NdFeB/锶铁氧体复合磁体性能的影响

采用流动温压成型技术制备了各向同性粘结NdFeB/锶铁氧体复合磁体。研究了不同类型NdFeB磁粉对粘结NdFeB/锶铁氧体复合磁体磁性能和交换耦合作用的影响。结果表明,粘结贫稀土NdFeB/锶铁氧体复合磁体的综合磁性能最好,当NdFeB和铁氧体的质量比为3:2时,其磁性能Br=0.38 T,Hcj=524 kA/m,(BH)max=21.9 kJ/m3;另外,其Henkel曲线为典型的S型曲线。粘结纳米双相NdFeB/锶铁氧体复合磁体内的交换耦合作用近乎消失,磁体内以静磁交互作用为主。