The System of Signal Detection Based on Sensing Needle

Biologic systems frequently have electric activity associated with them. This activity can be a constant dc electric field, a constant flux of charge-carrying particles or current, or a time-varying electric field or current associated with some time-dependent biologic or biochemical phenomenon. The mechanism of electric conductivity in the body involves ions as charge carriers. Thus, picking up bioelectric signals involves interacting with these ionic charge carriers and transducing ionic currents into electric currents required by wires and electronic instrumentation. Calcium ion is so important in our body, which plays a crucial role in metabolism.The common methods of detecting calcium ion include radioactive tracer method, activation shine protein method, etc, we choose calcium ion sensing needle as a tool to detect the calcium ion in the acupoint.

Diffusion in L10-Type Single Crystal TiAl and FePt Intermetallic Compounds

The diffusion coefficient of In in TiAl has been measured using ion implantation technique and secondary ion mass spectrometry. The diffusion coefficients of Fe and Pd in FePt have been measured at two compositions by radioactive tracer method. In order to clarify diffusion anisotropy, single crystal of each alloy was used. The In diffusion perpendicular to the [001] axis is faster than that parallel to the [001] axis. Such trend is similar to Ti diffusion previously measured in our group. The diffusion of Fe in FePt perpendicular to the [001] axis is faster than that parallel to the [001] axis at each composition, while the anisotropy of the Pd diffusion is different with composition. The predominant process of the diffusion in perpendicular to the [001] has been discussed on the basis of the expressions of the diffusion coefficients.

Counterion Effects on Interaction of Amphiphilic Quaternary Ammonium Salts with Model Membranes

The micellization as well as the interaction with model membranes of dodecyltrimethylammonium halides (DTAX) and N-dodecyl-N,N-dimethyl-N-benzylammonium halides (DBeAX) were studied at 298K and 313K by means of titration calorimetry. The calorimetric curves reflect both the counterion and benzyl group effects on the interaction of the surfactants studied with the lipid bilayer. Bromide as counterion enhanced the interactions more than chloride of both DTAX and DBeAX compounds with model membranes. Further, we studied the influence of DTAX and DBeAX on calcium ion desorption from the liposome membrane using a radioactive tracer method. DBeAX proved more efficient in desorption of calcium than DTAX. Iodides of these compounds enhanced this process more than bromides and chlorides.

Dynamics of Iron Uptake and Fe3O4 Biomineralization during Aerobic and Microaerobic Growth of Magnetospirillum gryphiswaldense

ABSTRACT Iron uptake and magnetite (Fe3O4) crystal formation could be studied in the microaerophilic magnetic bacteriumMagnetospirillum gryphiswaldense by using a radioactive tracer method for iron transport and a differential light-scattering technique for magnetism. Magnetite formation occurred only in a narrow range of low oxygen concentration, i.e., 2 to 7 μM O2 at 30°C. Magnetic cells stored up to 2% iron as magnetite crystals in intracytoplasmic vesicles. This extraordinary uptake of iron was coupled tightly to the biomineralization of up to 60 magnetite crystals with diameters of 42 to 45 nm.

Self and Impurity Diffusion in Icosahedral Al-Pd-Mn Quasicrystals

ABSTRACTDiffusivities of Cr in icosahedral quasicrystals of Al-Pd-Mn system have been measured by the radioactive tracer method in combination with a precision grinding technique. The temperature dependence of the diffusivities follows the Arrhenius equation in the investigated temperature range from 850 to 1107 K. The activation energy Q = 235.5 ± 7.8 kJmol-1 and pre-exponential factor D0 = 1.2 × 10-2 m2s-1 were evaluated. The diffusion behavior is discussed in terms of a vacancy diffusion mechanism.