Microstructural evolution,mechanical properties,and corrosion resistance of a heat-treated Mg alloy for the bio-medical application

During the recent years,some Mg based alloys have extensively been considered as a new generation of degradable and absorbable bio-medical materials.In this work,the Mg-2Zn-1Gd-1Ca(wt%)alloy as a new metallic bio-material was produced by the casting process followed by the heat treatment.The samples of the alloy were solution treated at temperatures of 500,550,and 600°C and then quench aged at temperatures of 125,150,and 175°C.The results of SEM-EDS examinations indicated that the alloy microstructure consists ofα-Mg matrix and the Ca_(2)Mg_(6)Zn_(3)and Mg_(3)Gd_(2)Zn_(3)secondary phases.With regard to the results of Vickers hardness test,the temperatures of 500°C and 150°C were selected as the optimum solutionizing and aging temperatures,respectively.Moreover,the dissolution of casting precipitates and production of lattice distortion occurring after the solution treatment led to the reduction in ultimate shear strength up to 21%.But,the precipitation hardening and morphological changes taking place during the aging treatment improved the ultimate shear strength up to 32%.Furthermore,the results of electro-chemical and weight-loss measurements in a simulated body fluid indicated that the heat-treated alloy is a promising candidate for the Mg based alloys recently considered for the bio-medical applications.

Development of a Peristaltic Micropump for Bio-Medical Applications Based on Mini LIPCA

This paper presents the design, fabrication, and experimental characterization of a peristaltic micropump. The micropump is composed of two layers fabricated from Polydimethylsiloxane （PDMS） material. The first layer has a rectangular channel and two valve seals. Three rectangular mini lightweight piezo-composite actuators are integrated in the second layer, and used as actuation parts. Two layers are bonded, and covered by two Polymethyl Methacrylate （PMMA） plates, which help increase the stiffness of the micropump. A maximum flow rate of 900μL.min 1 and a maximum backpressure of 1.8 kPa are recorded when water is used as pump liquid. We measured the power consumption of the micropump. The micropump is found to be a promising candidate for bio-medical application due to its bio-compatibility, portability, bidirectionality, and simple effective design.

Theory of Fiber Fluorescence and Wavelet Analysis Using in the Measurement of Bio-medical Temperature

The method of the temperature measurement based on the fluorescence lifetime and fiber transmitting technology is proposed. The certain or uncertain relationship between temperature and optical characteristics of some fluorescence material excited by function pulse or square wave pulse, and the temperature relativity of the feature are analyzed. The method based on the wavelet transformation theory is given to acquire temperature signals accurately and to remove the noise.

Bio-Medical Aspects of Purine Alkaloids

This review shortly summarized bio-medical activities of purine alkaloids, caffeine (caf), theophyline (top) and theobromine (tob). Caffeine potentiates the cytotoxicity of a variety of DNA domaging agents. Caffeine increased antitumor activity of some cancerostatic drugs. Caffeine inhibits the carcinogenic activity of cigarette smoke, significantly potentiating the therapeutic effect of acetaminophenol, cyclophosphoramide, enhances lipid oxidation, affects the central nervous system and alters cardiovascular system. Theophyline has expressive anti-inflammatory and antiasthmatic effect, and enhanced mobilization of lipid reduces the brain regional adenylate cyclase activity, facilitates glucose inhibition. Theophyline is muscle relaxant, vasodilator, diuretic and cardiac stimulant. Theobromine increases antitumor activity of adriamycin and doxorubicin, has expressive anti-inflammatory effect and it is classical diureticum. Several examples of caffeine with some organic substrates as well as with copper are also outlined. Increasing activity of the respective drugs in the present of the purine alkaloids can be ascribed to direct interaction as was proved by X-ray data of some caffeine adducts with organic substances as well as Cu(II) complexes.

Rough-Set-Based Attribute Dependencies: Foundations and Bio-Medical Data Applications

Theory of rough sets, proposed by Zdzislaw Pawlak in 1982, is a model of approximate reasoning. In applications, rough set methodology focuses on approximate representation of knowledge derivable from data. It leads to significant results in many areas including, for example, finance, industry, multimedia, medicine, and most recently bioinformatics.

Lipid Is Moving to the Forefront of Bio-Medical Research

While conventionally perceived as major components of cellular membranes and lipid droplets （LDs）, lipids have now emerged as key players with distinctive roles involving in a wide range of biological processes such as signaling events, trafficking, and compartmentalization of macromolecules. One of the key concerns in lipid research is its homeostasis, which is fundamental to health maintenance of cells, living organisms and human beings. It is evident now that deregulated lipid metabolism plays very important roles in many human diseases such as type 2 diabetes, cardiovascular diseases, Alzheimer＇s disease （AD）, Parkinson＇s disease, cancer and infectious diseases （Lam and Shui, 2013）.

Fiber lenses for ultra-small probes used in optical coherent tomography

We present a design, construction and characterization of different variations of GRIN and ball fiber lenses, which were recently proposed for ultra-small biomedical imaging probes. Those fiber lens modules are made of a single mode fiber and a GRIN or ball fiber lens with or without a fiber spacer between them. The lens diameters are smaller than 0.3 mm. We discuss design methods, fabrication techniques, and measuring performance of the fiber lenses. The experimental results are compared to their modeling results. The fabrication of a high quality beam director for both lens types is presented as well. These fiber integrated beam directors could be added on the tips of the fiber lenses for side-view probes. A needle probe made by these fiber lenses is demonstrated as a sample of the ultra-small probe for biomedical imaging application. In vivo human finger images acquired by a swept source optical coherence tomography using the fiber lenses with different beam profiles were shown, which indicates the important impact of

Design of low-offset low-power CMOS amplifier for biosensor application

A compacted and low-offset low-power CMOS am- plifier for biosensor application is presented in this paper. It includes a low offset Op-Amp and a high precision current reference. With a novel continuous-time DC offset rejection scheme, the IC achieves lower offset voltage and lower power consumption compared to previous designs. This configuration rejects large DC offset and drift that exist at the skin-electrode interface without the need of external components. The proposed amplifier has been implemented in SMIC 0.18-μm 1P6M CMOS technol-ogy, with an active silicon area of 100 μm by 120 μm. The back-annotated simulation results demonstrated the circuit features the systematic offset voltage less than 80 μV, the offset drift about 0.27 μV/℃ for temperature ranging from –30℃ to 100℃ and the total power dissipation consumed as low as 37.8 μW from a 1.8 V single supply. It dedicated to monitor low amplitude biomedical signals recording.