The dielectric properties of membrane and cytoplasm of cells were commonly derived using the experimental electrorotation spectra, which are proportional to the spectra of the imaginary part of the Clausius-Mossotti factor (Ki). However, it was found in this study that the cell properties thus derived do not agree with those derived using the experimental spectra of the real part of the Clausius-Mossotti factor (Kr). Both the Kr and Ki spectra are required simultaneously for deriving appropriate cell dielectric properties. Also the membrane and cytoplasm conductivities decrease, while the membrane and cytoplasm permittivities remain relatively unchanged, as the medium conductivity decreases.

Hemostasis, a process which causes bleeding to stop, can be enhanced using chitosan; but the detailed mechanism is unclear. Red blood cells (RBCs) adhere to chitosan because of their opposite charges, but the adhesion force is small, 3.83 pN as measured here using an optical tweezer, such that the direct adhesion cannot be the sole cause for hemostasis. However, it was observed in this study that layer structures of aggregated RBCs were formed next to chitosan objects in both static and flowing environments, but not formed next to cotton and rayon yarns. The layer structure is the clue for the initiation of hemostatsis. Through the supporting measurements of zeta potentials of RBCs and pH's using blood-chitosan mixtures, it is proposed here that the formation of the RBC layer structure next to chitosan objects is due to the reduction of repulsive electric double layer force between RBCs, because of the association of H+ deprotonated from chitosan with COO− on RBC membrane, under the DLVO (Derjaguin-Landau-Verwey-Overbeek) theory. The results are beneficial for designing effective chitosan-based wound dressings, and also for general biomedical applications.

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The solar-powered LED lighting system has been commercialized for a long time. The system usually consists of a DC to DC converter in order to convert the battery voltage into a fixed voltage or current for the LED lighting luminaire. This will cause energy loss and system reliability due to the failure of DC/DC converter. In the present study, we develop a special technique to drive the LED luminaire directly from battery utilizing PWM technique in order to remove the DC/DC converter. However, instantaneous current overdriven can occur easily due to the variation of battery voltage with the state-of-charge of battery.In the present study, we setup a thermal chamber with temperature variation to within 40±3 o C. A LED luminaire was specially designed for the LED reliability test with four different circuits with each circuit connecting three LED lamps serially. A driver is designed to provide 4 kinds of power inputs to LED: (a) 350mA constant current, (b) 700mA,100Hz, duty cycle=50%, (c)700mA, 10K Hz duty cycle=50% and (d) 1050mA, 100Hz, duty cycle=33%. The tests were performed simultaneously to compare light decay between normal drive condition (a) and other PWM driving conditions (b, c, d). The accumulated total test time so far is more then 7,032 hours and has shown no significant light decay in 4 different loops. This reveals that the PWM technique directly driven by battery is feasible and is able to reduce energy loss of DC to DC converter in the solar lighting system.

We fabricated AlGaAs/GaAs heterostructurebased quantum Hall devices for the resistance standard at Center for Measurement Standards (CMS). The measurements using a Direct Current Comparator (DCC) show the consistency between the plateaus of =2 and 4 at the temperature T=2 K, where is the filling factor. On the other hand, the plateaus of higher filling factors may be susceptible to the reduced localization strength, under which the semiclassical effects can be important. The