Characterization of the major whey proteins from milk of Mediterranean water buffalo (Bubalus bubalis)

In this work, the whey protein fractions from 120 Mediterranean water buffalo individual milks were analysed by microchip electrophoresis (MCE), reverse-phase high-performance liquid chromatography (RP-HPLC) and mass spectrometry (ESI-MS). Validation procedures were carried out for both MCE and HPLC. The chromatographic analysis allowed the complete separation of the whey protein fractions, resulting in a well-defined peak structure; the adopted RP-HPLC and ESI-MS protocols provided identification of β-lactoglobulin (18,266 Da), α-lactoalbumin (14,236 Da) and serum albumin (66,397 Da). The calculated mean concentrations were 4.04 g/l, 2.45 g/l and 0.35 g/l, respectively.     

REVISITING ELECTROOSMOTIC FLOW: AN IMPORTANT PARAMETER AFFECTING SEPARATION IN CAPILLARY AND MICROCHIP ELECTROPHORESIS

Electroosmotic flow mobility (EOF) is the movement of bulk liquid that provides an opportunity to separate charged molecules, either positive or negative, and transport all neutral molecules to the detector as a single peak. EOF originates on the silanol groups of the fused-silica capillary wall and is usually responsible for ions moving in the opposite direction of the electrostatic attraction. The interaction of the silanol groups with the electrolyte buffer leads to the formation of an electric double layer. Understanding double-layer theory and EOF is the first necessary step towards understanding many of the experimental observations in capillary and microchip electrophoresis. In this work, we introduce and validate a method to measure the EOF on both coated and uncoated capillaries by measuring the current time history, which has led to enhanced precision of the EOF measurement. We have also used the introduced method to study the fundamental parameters, such as the effect of electric field, temperature, buffer ionic strength, and pH on electroosmotic flow.     

微芯片电泳仪定量测定混合肉中各肉成分

目的基于微芯片电泳仪开发一种鉴定混合肉的定量方法。方法采用商品化试剂盒对不同比例混合的牛肉和猪肉进行处理,无需精制DNA,直接进行PCR过程。全自动的微芯片电泳仪,不仅可以测量DNA/RNA的片段长度,且采用了内标物和样品的同时出峰,通过两者峰面积的比值,可以测量出样品出峰片段的相应浓度。本文使用微芯片电泳仪测定不同比例混合的猪肉和牛肉目标PCR产物片段的长度和浓度,制作标准曲线。结果在猪肉和牛肉混合肉样品中检测到相应的目标PCR产物,并且两种肉的PCR目标产物浓度和样品的质量呈大致的线性关系。结论使用本方法可以实现混合肉中各成分的定量检测,为肉类掺假的鉴定提供了一种有力的分析手段。     

Comparison of laser generation in thermally bonded and unbonded Er3+,Yb3+:glass/Co2+:MgAl2O4 microchip lasers

Pulse laser generation in several Er³⁺,Yb³⁺:glasses thermally bonded with Co²⁺:MgAl₂O₄ was achieved. Peak power in the range of 1.83–7.68 kW with pulse duration between 2.9 and 4.2 ns and energy up to 24 μJ was obtained. The output characteristics for different transmissions of the output couplers were investigated. To show the improvements gained by the thermal bonding procedure, a comparison of thermally bonded and unbonded samples was done in terms of generation efficiency, peak power, beam quality, generated spectra and pulse to pulse jitter.     

Temperature-dependent spectroscopy and microchip laser operation of Nd:KGd(WO4)2

High-resolution absorption and stimulated-emission cross-section spectra are presented for monoclinic Nd:KGd(WO₄)₂ (Nd:KGW) laser crystals in the temperature range 77–450 K. At room-temperature, the maximum stimulated emission cross-section is σ_SE = 21.4 × 10⁻²⁰ cm² at 1067.3 nm, for light polarization E || N_m. The lifetime of the ⁴F_3/2 state of Nd³⁺ in KGW is practically temperature independent at 115 ± 5 μs. Measurement of the energy transfer upconversion parameter for a 3 at.% Nd:KGW crystal proved that this was significantly smaller than for alternative hosts, ∼2.5 × 10⁻¹⁷ cm³/s. When cut along the N_g optical indicatrix axis, the Nd:KGW crystal was configured as a microchip laser, generating ∼4 W of continuous-wave output at 1067 nm with a slope efficiency of 61% under diode-pumping. Using a highly-doped (10 at.%) Nd:KGW crystal, the slope efficiency reached 71% and 74% when pumped with a laser diode and a Ti:Sapphire laser, respectively. The concept of an ultrathin (250 μm) Nd:KGW microchip laser sandwiched between two synthetic diamond heat-spreaders is demonstrated.     

三维打印成形技术在制药工程中的应用

快速成形与制药工程的结合体现了先进制造技术的发展方向。介绍了采用三维打印成形技术制造先进可控释放和智能微晶片药物的方法，并分析了这种方法的优势和可行性，进一步讨论了三维打印成形技术应用于制药工程所涉及到的一些关键技术。     

全内腔Nd:YVO4微片激光器稳频研究

研究了全内腔Nd:YVO4微片激光器的温度稳频控制。分析了影响Nd:YVO4微片激光器频率的因素和频率变化对系统测量误差带来的影响。设计了合理的机械结构和控制电路,通过采用温度控制的方法进行稳频,介绍了系统的组成成分及各个元件的作用。实验分析了频率和输出功率之间的关系,在此基础上优化了系统的结构。实现稳频控制后,显著提高了激光器的频率稳定性,频率稳定度能达到(10^-7~10^-8),改进了系统的工作性能,以满足高精度的测量需求,使其在精密测量技术领域具有更广阔的发展前景。     

基于80C552的一种测量电感方法

针对常用相位差法测量电感时输入端和输出端电压的相位差存在抖动的问题,提出了通过电路互锁原理以消除抖动的相位差测量电路.该电路利用D触发器,相位差只被输出一次;由于选用10M晶振,相位差的计时单位达0.1μs;并使测量电感的直流内阻变得简单.根据此原理,选用80C552构成了单片机测量系统,实现了内阻测量方式和相位差测量方式的切换,并具有与上位机的串行通讯功能.该系统适用于电磁铁产品的综合测试.     

一种基于新型信息钮扣的巡更系统

介绍美国Dallas公司的新产品信息钮扣的特点、性能、阐述了以单片机为核心的巡更系统软硬件设计及相应微机软件设计。     

STUDY OF CAPILLARY ELECTROPHORESIS ON MICROCHIP BASED ON MEMS

Using a standard photolithographical procedure,chenmical wet etching and thermal diffusion bonding technology,a chemical analysis device for Capillary Electrophoresis(CE) has been microfabricated on a planar glass substrate with a cross-column geometry.The channels on the microchip substrate are about 50um deep and 150um wide.By employing amino acids derived from 2,4-DiNitroFluoroBenzen(DNFB) on CE chip channels,the sample manipulating system is studied based on the principle of electrodynamics.