Impact of Chronic Hepatitis C Virus Genotype 1b Infection on Triglyceride Concentration in Serum Lipoprotein Fractions

Reduced low-density lipoprotein (LDL) cholesterol level is a characteristic feature of dyslipidemia in chronic hepatitis C virus (HCV) infection. However, abnormality in serum triglyceride (TG) has not been fully investigated. To clarify the impact of HCV genotype 1b (G1b) infection and advanced fibrosis on serum TG profiles, TG concentrations in lipoprotein fractions were examined in fasting sera from 185 subjects with active or cleared HCV infection by high-performance liquid chromatography. Serum lipoproteins were fractionated into four classes: chylomicron, very low-density lipoprotein (VLDL), LDL, and high-density lipoprotein (HDL). Then, the significance of HCV G1b infection on TG levels in each lipoprotein fraction was determined using multiple regression models. We found that active HCV G1b infection was positively associated with high HDL-TG levels and low VLDL-TG levels, independent of other factors included in the regression model. In VLDL sub-fractions, active HCV infection was only found to be associated with low levels of large VLDL-TG. Similarly, advanced liver fibrosis in chronic HCV G1b infection was associated with high levels of LDL-TG, HDL-TG, and small VLDL-TG, independent of other clinical factors. These findings indicate that active HCV G1b infection and advanced fibrosis are closely associated with abnormal serum TG profiles.     

Ambulatory estimation of knee-joint kinematics in anatomical coordinate system using accelerometers and magnetometers

Knee-joint kinematics analysis using an optimal sensor set and a reliable algorithm would be useful in the gait analysis. An original approach for ambulatory estimation of knee-joint angles in anatomical coordinate system is presented, which is composed of a physical-sensor-difference-based algorithm and virtual-sensor-difference-based algorithm. To test the approach, a wearable monitoring system composed of accelerometers and magnetometers was developed and evaluated on lower limb. The flexion/extension (f/e), abduction/adduction (a/a), and inversion/extension (i/e) rotation angles of the knee joint in the anatomical joint coordinate system were estimated. In this method, since there is no integration of angular acceleration or angular velocity, the result is not distorted by offset and drift. The three knee-joint angles within the anatomical coordinate system are independent of the orders, which must be considered when Euler angles are used. Besides, since there are no physical sensors implanted in the knee joint based on the virtual-sensor-difference-based algorithm, it is feasible to analyze knee-joint kinematics with less numbers and types of sensors than those mentioned in some others methods. Compared with results from the reference system, the developed wearable sensor system is available to do gait analysis with fewer sensors and high degree of accuracy.     

Interlaboratory validation of quantitative duplex real-time PCR method for screening analysis of genetically modified maize

To reduce the cost and time required to routinely perform the genetically modified organism (GMO) test, we developed a duplex quantitative real-time PCR method for a screening analysis simultaneously targeting an event-specific segment for GA21 and Cauliflower Mosaic Virus 35S promoter (P35S) segment [Oguchi et al., J. Food Hyg. Soc. Japan, 50, 117-125 (2009)]. To confirm the validity of the method, an interlaboratory collaborative study was conducted. In the collaborative study, conversion factors (Cfs), which are required to calculate the GMO amount (%), were first determined for two real-time PCR instruments, the ABI PRISM 7900HT and the ABI PRISM 7500. A blind test was then conducted. The limit of quantitation for both GA21 and P35S was estimated to be 0.5% or less. The trueness and precision were evaluated as the bias and reproducibility of the relative standard deviation (RSD(R)). The determined bias and RSD(R) were each less than 25%. We believe the developed method would be useful for the practical screening analysis of GM maize.     

A study of a two stage maximum power point tracking control of a photovoltaic system under partially shaded insolation conditions

A photovoltaic (PV) array shows relatively low output power density, and has a greatly drooping current–voltage (I–V) characteristic. Therefore, maximum power point tracking (MPPT) control is used to maximize the output power of the PV array. Many papers have been reported in relation to MPPT. However, the current–power (I–P) curve sometimes shows multi-local maximum point mode under non-uniform insolation conditions. The operating point of the PV system tends to converge to a local maximum output point which is not the real maximal output point on the I–P curve. Some papers have been also reported, trying to avoid this difficulty. However, most of those control systems become rather complicated. Then, the two stage MPPT control method is proposed in this paper to realize a relatively simple control system which can track the real maximum power point even under non-uniform insolation conditions. The feasibility of this control concept is confirmed for steady insolation as well as for rapidly changing insolation by simulation study using software PSIM and LabVIEW.     

An application of a homogenization method to the estimation of effective thermal conductivity of a hydrogen storage alloy bed considering variation of contact conditions between alloy particles

A homogenization method is applied to the estimation of effective thermal conductivity of a hydrogen storage alloy bed. By including the contact conditions between the alloy particles, the effect of contact conditions on the thermal conductivity is investigated.     

Three-dimensional positioning of optically trapped nanoparticles

We firstly demonstrate the three-dimensional (3D) measurement of a nanometer-sized sphere held in optical tweezers in water using an in-line digital holographic microscope with a green light emitting diode. Suppressing the movement with optical tweezers enabled us to detect the three-dimensional position of a polystyrene sphere with a diameter of 200 nm. The positioning resolutions of the microscope were 3.2 nm in the transverse direction and 3.4 nm in the axial direction, from the standard deviation of measurements of the 200 nm sphere fixed on glass. Changes in the Brownian motion in response to a change in the trapping laser power were measured. We also demonstrated that this holographic measurement is an effective method for determining the threshold power of the optical trapping.     

The influence of operation temperature on the output properties of amorphous silicon-related solar cells

The influence of the operation temperature on the output properties of solar cells with hydrogenated amorphous silicon (a-Si:H) and hydrogenated amorphous silicon germanium (a-SiGe:H) photovoltaic layers was investigated. The output power after longtime operation of an a-Si:H single junction, an a-Si:H/a-Si:H tandem, and an a-Si:H/a-SiGe:H tandem solar cell was calculated based on the experimental results of two types of temperature dependence for both conversion efficiency and light-induced degradation. It was found that the a-Si:H/a-SiGe:H tandem solar cell maintained a higher output power than the others even after longtime operation during which a temperature range of 25°C to 80°C. These results confirm the advantages of the a-Si:H/a-SiGe:H tandem solar cell for practical use, especially in high-temperature regions.     

Phase‐Change Materials: Vibrational Softening upon Crystallization and Its Impact on Thermal Properties

Crystallization of an amorphous solid is usually accompanied by a significant change of transport properties, such as an increase in thermal and electrical conductivity. This fact underlines the importance of crystalline order for the transport of charge and heat. Phase‐change materials, however, reveal a remarkably low thermal conductivity in the crystalline state. The small change in this conductivity upon crystallization points to unique lattice properties. The present investigation reveals that the thermal properties of the amorphous and crystalline state of phase‐change materials show remarkable differences such as higher thermal displacements and a more pronounced anharmonic behavior in the crystalline phase. These findings are related to the change of bonding upon crystallization, which leads to an increase of the sound velocity and a softening of the optical phonon modes at the same time.     

Thermal conductivity evaluation of high burnup mixed-oxide (MOX) fuel pellet

The thermal conductivity formula of fuel pellet which contains the effects of burnup and plutonium (Pu) addition was proposed based on the Klemens’ theory and reported thermal conductivities of unirradiated (U, Pu) O₂ and irradiated UO₂ pellets. The thermal conductivity of high burnup MOX pellet was formulated by applying a summation rule between phonon scattering parameters which show the effects of plutonium addition and burnup. Temperature of high burnup MOX fuel was evaluated based on the thermal conductivity integral which was calculated from the above-mentioned thermal conductivity formula. Calculated fuel temperatures were plotted against the linear heat rates of the fuel rods, and were compared with the fuel temperatures measured in a test reactor. Since both values agreed well, it was confirmed that the proposed thermal conductivity formula of MOX pellets is adequate.