Fluorometric Quantification of Human Platelet Polyphosphate Using 4′,6-Diamidine-2-phenylindole Dihydrochloride: Applications in the Japanese Population

Polyphosphate (polyP), a biopolymer of inorganic phosphate, is widely distributed in living organisms. In platelets, polyP is released upon activation and plays important roles in coagulation and tissue regeneration. However, the lack of a specific quantification method has delayed the in-depth study of polyP. The fluorescent dye 4′,6-diamidine-2-phenylindole dihydrochloride (DAPI) has recently received attention as a promising probe for the visualization and quantification of cellular polyP levels. In this study, we further optimized quantification conditions and applied this protocol in quantification of platelet polyP levels in a Japanese population. Blood samples were collected from non-smoking, healthy Japanese subjects (23 males, 23 females). Washed platelets were fixed and probed with DAPI for fluorometric determination. PolyP levels per platelet count were significantly higher in women than that in men. A moderate negative correlation between age and polyP levels was found in women. Responsiveness to CaCl₂ stimulation was also significantly higher in women than that in men. Overall, our optimized protocol requires neither purification nor degradation steps, reducing both the time and bias for reproducible quantification. Thus, we suggest that despite its low specificity, this DAPI-based protocol would be useful in routine laboratory testing to quantify platelet polyP levels efficiently and economically.     

Development of a calculation method for estimating specific energy distribution in complex radiation fields

Estimation of the specific energy distribution in a human body exposed to complex radiation fields is of great importance in the planning of long-term space missions and heavy ion cancer therapies. With the aim of developing a tool for this estimation, the specific energy distributions in liquid water around the tracks of several HZE particles with energies up to 100 GeV n(-1) were calculated by performing track structure simulation with the Monte Carlo technique. In the simulation, the targets were assumed to be spherical sites with diameters from 1 nm to 1 microm. An analytical function to reproduce the simulation results was developed in order to predict the distributions of all kinds of heavy ions over a wide energy range. The incorporation of this function into the Particle and Heavy Ion Transport code System (PHITS) enables us to calculate the specific energy distributions in complex radiation fields in a short computational time.     

Performance test of personal RF monitor for area monitoring at magnetic confinement fusion facility

For safety management at a magnetic confinement fusion-test facility, protection from not only ionising radiation, but also non-ionising radiation such as the leakage of static magnetic and electromagnetic fields is an important issue. Accordingly, the use of a commercially available personal RF monitor for multipoint area monitoring is proposed. In this study, the performance of both fast- and slow-type personal RF monitors was investigated by using a transverse electromagnetic cell system. The range of target frequencies was between 10 and 300 MHz, corresponding to the ion cyclotron range of frequency in a fusion device. The personal RF monitor was found to have good linearity, frequency dependence and isotropic response. However, the time constant for the electric field sensor of the slow-type monitor was much longer than that for the fast-type monitor. Considering the time-varying field at the facility, it is found that the fast-type monitor is suitable for multipoint monitoring at magnetic confinement fusion test facilities.     

Reconstructing arbitrarily focused images from two differently focused images using linear filters.

We present a novel filtering method for reconstructing an all-in-focus image or an arbitrarily focused image from two images that are focused differently. The method can arbitrarily manipulate the degree of blur of the objects using linear filters without segmentation. The filters are uniquely determined from a linear imaging model in the Fourier domain. An effective and accurate blur estimation method is developed. The simulation results show that the accuracy and computational time of the proposed method are improved compared with the previous iterative method and that the effects of blur estimation error on the quality of the reconstructed image are very small. The method performs well for real images acquired without visible artifacts.     

An interior surface generation method for all-hexahedral meshing

This paper describes an all-hexahedral generation method focusing on how to create interior surfaces. It is well known that a solid homeomorphic to a ball with even number of bounding quadrilaterals can be partitioned into a compatible hexahedral mesh where each associated hexahedron corresponds to the intersection of three interior surfaces that are dual to the original hexahedral mesh. However, no such method for creating dual interior surfaces has been developed for generating all-hexahedral meshes of volumes covered with simply connected quadrilaterals. We generate an interior surface as an orientable regular homotopy (or more definitively a sweep) by splitting a dual cycle into several pieces at self-intersecting points and joining the three connected pieces, if the self-intersecting point-types are identical, while we generate a non-orientable surface (containing Möbius bands) if the self-intersecting point-types are distinct. Stitching these simple interior surfaces together allows us to compose more complex interior surfaces. Thus, we propose a generalized method of generating a hexahedral mesh topology by directly creating the interior surface arrangement. We apply the present framework to Schneiders’ open pyramid problem and show an arrangement of interior surfaces that decompose Schneiders’ pyramid into 146 hexahedra.     

Sketch-Based Spatial Queries for Retrieving Human Locomotion Patterns From Continuously Archived GPS Data

We propose a system for retrieving human locomotion patterns from tracking data captured within a large geographical area, over a long period of time. A GPS receiver continuously captures data regarding the location of the person carrying it. A constrained agglomerative hierarchical clustering algorithm segments these data according to the person's navigational behavior. Sketches made on a map displayed on a computer screen are used for specifying queries regarding locomotion patterns. Two basic sketch primitives, selected based on a user study, are combined to form five different types of queries. We implement algorithms to analyze a sketch made by a user, identify the query, and retrieve results from the collection of data. A graphical user interface combines the user interaction strategy and algorithms, and allows hierarchical querying and visualization of intermediate results. We evaluate the system using a collection of data captured during nine months. The constrained hierarchical clustering algorithm is able to segment GPS data at an overall accuracy of 94% despite the presence of location-dependent noise. A user study was conducted to evaluate the proposed user interaction strategy and the usability of the overall system. The results of this study demonstrate that the proposed user interaction strategy facilitates fast querying, and efficient and accurate retrieval, in an intuitive manner.     

Diabetes-induced and age-related changes in fatty acid proportions of plasma lipids in rats

Diabetes-induced and age-related proportional changes in plasma fatty acids of triglycerides (TG), phospholipids (PL), and cholesteryl esters (CE) were investigated using streptozotocin-induced diabetic and control rats. Among n-6 fatty acids from diabetic rat plasma, increased proportions of 18∶2n-6 and 20∶3n-6 in all three lipid classes and of 18∶3n-6 in PL at 1–3 months old and in TG at 3–5 months old were observed. The proportions of 20∶4n-6 decreased in both PL and CE, but were unchanged in diabetic TG. Among the n-3 fatty acids, in the early stage, diabetes caused increases in the proportions of 18∶3n-3 in PL and CE and of 20∶5n-3 and 22∶6n-3 in TG, while 22∶5n-3 was decreased later in the disease course. These results suggest reduced Δ5-desaturase activities on 20∶3n-6 but not on 20∶4n-3, while Δ6-desaturase activity on 18∶2n-6 was essentially unaffected. Furthermore, the reduction in Δ9-desaturase activity in diabetic rats may well explain the decreases in the proportions of 16∶1n-7 and 18∶1n-7. However, the proportion of 18∶1n-9, another product of Δ9-desaturase, was significantly increased in CE and PL as compared to the controls. Thus, there was a discrepancy between our results and those of earlier studies with respect to the n-9, n-6, and n-3 fatty acid proportions of plasma lipids in diabetic rats. We also investigated age-related changes in the proportions of plasma fatty acids. Although rather small, age-related changes were evident in both diabetic and control rats.     

Alkaline Corrosion Resistance of Anodized Aluminum Coated with Zirconium Oxide by a Sol-Gel Process

To improve the alkaline corrosion resistance of aluminum, composite films were prepared that consisted of a porous layer of anodically grown aluminum oxide filled with zirconium oxide, with a zirconium oxide coating layer that was deposited thereon via the sol—gel process, using a dip-coating technique. The alkaline corrosion resistance of these composite films was extremely improved when this coating layer was placed on an anodic oxide film. Comparisons of the composite film and conventional anodic oxide film showed that the alkaline corrosion resistance of the composite film was increased by a factor of 24–50. Because these composite films, which have high corrosion resistance, indicated a vibration phenomenon of voltage in the duration time curve of the electromotive force measurement, the composite film had a self-repairing action for alkaline corrosion.