Sensitive Solid Reagent For Formaldehyde,And A New Formaldehyde Generator

Abstract

A solid reagent of Purpald®-acetone aminal on sodium or potassium bicarbonate responds to formaldehyde in the sub-ppm concentration range. A purple color (λ=560 nm) is developed proportional to concentration of formaldehyde and time of exposure after wetting with a 90% acetone-10% water solution. The reagent should be of value as a semi-quantitative warning device for the presence of formaldehyde. A device is described which generates formaldehyde in air in the sub-ppm concentration range at room temperature with desired relative humidity. This generator could be used in the same manner to generate low concentrations of other substances of low volatility.     

Activity of Lambda-Exonuclease on Surface-Attached Oligonucleotide Detected by Acoustic Wave Device and Radiochemical Labeling

Abstract

Single-strand 25-mer oligonucleotides have been attached to the surface of a 9-MHz acoustic wave sensor incorporated into a flow-through configuration. This was achieved by an online interaction of the biotinylated probe with chemisorbed neutravidin. Duplex formation with complementary 25-mer was monitored by acoustic wave detection in real time. Regeneration of the probe-modified surface was achieved using online introduction of λ-exonuclease, an enzyme that digests a single strand of double-stranded DNA beginning with the 5′ end, cleaving single nucleotides as it progresses. Thus, with the 5′ end of the probe strand remaining inaccessible because of the biotin-neutravidin linkage, the target strand was successfully removed by enzymatic digestion. The results of the acoustic wave work are correlated with analogous experiments involving oligonucleotides labeled with ³²P.     

A Telemetry-Instrumentation System for Long-Term Implantable Glucose and Oxygen Sensors

Abstract

This paper describes the development of a compact, low power, implantable system for in vivo monitoring of oxygen and glucose concentrations. The telemetry-instrumentation system consists of two amperometric sensors: one oxygen and one glucose biosensor and two potentiostats for biasing the sensors, an instrumentation amplifier to subtract and amplify sensor output signals, and a signal transmitter subunit to convert and transmit glucose dependent signal from the sensors to a remote data acquisition system. The system produces a unipolar glucose dependent voltage in the range of 1 to 3.6 V which is converted to a frequency and then transmitted using a frequency-modulated (FM) oscillator. Initial tests were performed on an open model electronic circuit using resistors to simulate sensor outputs in the 10 to 1000 nA range. Further in vitro evaluation of the system was conducted with a compact printed circuit board embedded in silicone elastomer, entirely submerged in buffer solution using actual sensors. The test results indicated satisfactory operation of the system in simulated implantation conditions for seven days. Response curve of transmitted signal vs glucose concentration was obtained. The results of the in vitro evaluation of the telemetry system permits its subcutaneous implantation in an animal model.     

药物磁靶向定位释放模拟装置的设计与应用

采用蠕动泵、钕铁硼永磁铁、聚乙烯管、恒温水浴锅和玻璃管组装了一种模拟人体血液循环的磁靶向装置,并应用于模型磁性载药粒子Fe3O4@DFUR-LDH（DFUR：去氧氟尿苷;LDH：硝酸根插层水滑石）的磁靶向定位和药物释放性能的分析。 研究发现,该装置对磁性载药粒子的滞留量最高可达85.3%,并随载药粒子与磁场的间距增大而减小,随释放介质的流速增大而减小。 而装置中模型磁性载药粒子的药物释放速率随释放介质的流速增大而增大。 同时,通过修改该装置的管路系统模拟了药物在治疗过程中不断被消耗情形下的磁靶向治疗过程。 该装置不但可以实现磁性载药粒子的滞留,还可以分析磁性载药粒子被滞留后的定位释放行为,是磁性载药粒子临床试验前性能分析测试的有效工具。     

Effect of Device Fabrication Conditions on Photovoltaic Performance of Polymer Solar Cells Based on Poly(3‐hexylthiophene) and Indene‐C70 Bisadduct

Effect of the device fabrication conditions on photovoltaic performance of the polymer solar cells based on poly(3‐hexylthiophene) (P3HT) as donor and indene‐C₇₀ bisadduct (IC₇₀BA) as acceptor was studied systematically. The device fabrication conditions we studied include pre‐thermal annealing temperature, active layer thickness, and the P3HT:IC₇₀BA weight ratios. For devices with a 188‐nm‐thick active layer of P3HT:IC₇₀BA (1:1, w:w) blend film and pre‐thermal annealing at 150°C for 10 min, maximum power conversion efficiency (PCE) reached 5.82% with V_oc of 0.81 V, I_sc of 11.37 mA/cm², and FF of 64.0% under the illumination of AM1.5G, 100 mW/cm².     

Fabrication and properties of high performance YBa_2Cu_3O_(7-δ) radio frequency SQUIDs with step-edge Josephson junctions

We describe the fabrication of high performance YBa2Cu3O7-δ（YBCO） radio frequency（RF） superconducting quantum interference devices（SQUIDs）, which were prepared on 5 mm×5 mm LaAlO3（LAO） substrates by employing stepedge junctions（SEJs） and in flip-chip configuration with 12 mm×12 mm resonators. The step in the substrate was produced by Ar ion etching with step angles ranging from 47°to 61°, which is steep enough to ensure the formation of grain boundaries（GBs） at the step edges. The YBCO film was deposited using the pulsed laser deposition（PLD） technique with a film thickness half of the height of the substrate step. The inductance of the SQUID washer was designed to be about 157 pH.Under these circumstances, high performance YBCO RF SQUIDs were successfully fabricated with a typical flux-voltage transfer ratio of 83 mV/Φ0, a white flux noise of 29 μΦ0/（Hz）^1/2, and the magnetic field sensitivity as high as 80 fT/（Hz）^1/2.These devices have been applied in magnetocardiography and geological surveys.     

Preparation of Multilayered Polymeric Structures Using a Novel Four‐Needle Coaxial Electrohydrodynamic Device

Coaxial four‐needle electrohydrodynamic forming is applied for the first time to prepare layered structures in both particle and fiber form. Four different biocompatible polymers, polyethylene glycol, poly (lactic‐co‐glycolic acid), polycaprolactone, and polymethylsilsesquioxane, are used to generate four distinct layers confirmed using transmission and scanning electron microscopy combined with focused ion beam milling. The incorporation and release of different dyes within the polymeric system of four layers are demonstrated, something that is much desired in modern applications such as the polypill where multiple active pharmaceutical ingredients can be combined to treat numerous diseases.

     

金属纳米柱天线的快速电磁分析

基于分段正弦基函数和矩量法,通过求解离散电流节点格林函数的封闭解得到金属纳米柱天线激发表面等离子体的阻抗矩阵.与使用其它基函数矩量法相比,该方法可以减少矩阵方程的维数.仿真结果表明:使用此方法只需求解很小的矩阵方程就可以求解出纳米天线表面极化电流,从而实现对纳米天线的散射特征及谐振模式的快速分析;其结果与时域有限差分仿真结果吻合良好且速度具有显著的优势,尤其在计算斜入射问题时计算优势更加明显.本文的方法对文中计算的模型有效,同样为其他形状纳米柱天线和碳纳米管器件散射特性仿真提供了快速有效的电磁分析方法.     

模拟触电演示仪

设计了模拟触电演示仪,在低压直流电条件下,通过操作布偶来生动模拟人体触电的各种情形.学生可从视觉、听觉和触觉多角度真切地体会到触电的反应,达到教育学生安全用电的教学效果.     

基于Zigbee与GPRS网络数据传输技术的黄河河道断面冰水情多点自动监测系统设计与应用

基于空气、冰与水物理特性差异的冰情检测方法是一种可以实现对检测点垂直柱面冰层内部物理状态连续在线检测的新型冰情检测方法.方法由于受测试点的局限,仅仅实现了对河道断面的单点取样数据采集,无法掌握河道断面整体冰生消变化的过程,在工程应用中受到限制.结合黄河冬季冰情现场实验的需求,在原有基于空气、冰与水物理特性差异的冰情检测系统基础上,融合了Zigbee和GPRS网络数据传输技术设计了一套黄河河道断面冰水情多点自动监测试验系统.现场试验结果表明,系统实现了对河道断面多点数据的连续实时采集和传输,可以满足工程中对河道断面多点实时监测的需求.