Nigrofrontal dopaminergic function as assessed by 18F-dopa PET

The existence of the nigrofrontal dopaminergic pathway has been demonstrated in neuroanatomical studies. We evaluated the presynaptic nigrofrontal dopaminergic function using 18F-dopa (FD) positron emission tomography (PET). The multiple time PET data in the frontal cortex from 20 to 70 min post-injection for FD were evaluated by Patlak analysis using the cerebellar time-activity curve as an input function. The frontal FD uptake rate constants could not be determined in 5 of 12 normal volunteers because of large deviations in the plots. There were no significant differences between the subjects among whom the frontal FD uptake rate constants could or could not be determined regarding the amount of FD injected, the frontal 18F counts, or whether or not they were pretreated with carbidopa. The uptake constants were determined in 9 or 12 patients with parkinsonian syndrome. While the mean (+/- S.D.) uptake constants in patients with Parkinson's disease (2.89 +/- 0.06 x 10(-3), n = 4) and in patients with progressive supranuclear palsy (2.81 +/- 0.10 x 10(-3), n = 3) were not significantly different from those in the normal volunteers (2.93 +/- 0.14 x 10(-3)), those in two patients with corticobasal degeneration (2.42 and 2.46, respectively) decreased in comparison to the control values. Differences in the nigrofrontal presynaptic dopaminergic function as assessed by FD-PET may explain the different pathogenesis and also help to differentiate between corticobasal degeneration and other parkinsonian syndromes, such as Parkinson's disease and progressive supranuclear palsy.     

Electric field-induced concentration and capture of DNA onto microtips

Simple, high-yield concentration of DNA is important for high-throughput genetic analysis and disease diagnosis. Glass-based microfilters are popular but the process requires centrifugation steps with cumbersome chemical processes. As an alternative, a concentration method using an electric field has been explored previously, but with limited efficiency. In this paper, electric field-induced concentration and capture of DNA are studied by using high-aspect-ratio microtips coated with a gold layer. The microtips are immersed longitudinally into a solution of 100???L containing ??-phage DNA. After DNA concentration using an electric field, the microtips are withdrawn from the solution. Under AC- and biased AC fields, DNA is concentrated by electrophoresis (EP), dielectrophoresis (DEP), and electroosmotic flow (EOF). To reduce capillary effects in the withdrawal process, the microtips are coated with positively charged poly-l-lysine (PLL). The pattern of captured DNA is analyzed by fluorescence microscopy. DEP attracts DNA molecules at the edges of microtips, where the highest gradient of electric field exists. EP attracts DNA onto the surface of microtips following the vectors of an electric field. EOF generates vortexes that deliver DNA onto microtips. Using this method, 85% of DNA is captured on the PLL-coated microtips after three sequential captures. The concentration mechanism can potentially facilitate rapid and simple preparation of DNA for downstream analysis.     

Junction properties of polypyrrole containing a small amount of poly(ethylene oxide) with indium

A method to generate a porous region near the surface of a polymer is suggested. In this method the region near the surface is swollen by immersing the polymer for a short time in a solvent. Subsequently, the polymer is introduced in a nonsolvent (for the polymer) that is, however, miscible with the solvent. The formation of the porous region is a result of (1) the swelling accompanied by the disentanglement of the surface molecular chains, and the dissolution of some of them during the immersion in the solvent, and (2) the rapid extraction of the solvent from the swollen region by the nonsolvent. The porous surface provides a matrix into which a second incompatible monomer can be polymerized so that the two otherwise incompatible polymers can adhere to one another.     

Sensitive Label-Free Immunoassay by Colorimetric Plasmonic Biosensors Using Silver Nanodome Arrays

The sensitive direct detection of biomolecules is demonstrated by a colorimetric plasmonic biosensor utilizing the surface colors of plasmonic metasurfaces named Ag nanodome arrays. The Ag nanodome arrays consist of polystyrene bead monolayers coated with Ag thin films whose surface colors are optimized by changing the size of the polystyrene beads. The bulk refractive index sensitivity of colorimetric detection evaluated using the hue angle is 590° RIU⁻¹ (RIU: refractive index unit). For selected geometry, the refractive index resolution (5.0 × 10⁻⁵ RIU) obtained by colorimetric detection surpasses that of spectroscopic detection evaluated via the dip wavelength in the reflection spectrum. The numerical simulations predict an enhanced sensing performance when the hue angle of the surface colors of the Ag nanodome arrays changes from 300° to 200°, corresponding to changes in the dip wavelength from 570 to 600 nm in the reflection spectra. Furthermore, the detection sensitivity of the biomolecules is characterized using a direct IgG immunoassay format. The detection limit of the IgG concentration is as low as 134 pM using simple colorimetric detection. The feasibility of sensitive label-free immunoassays using a colorimetric plasmonic biosensor is expected to accelerate the development of highly sensitive and reliable smartphone-based plasmonic biosensors.     

The Atmospheric Scanning Electron Microscope with open sample space observes dynamic phenomena in liquid or gas

Although conventional electron microscopy (EM) requires samples to be in vacuum, most chemical and physical reactions occur in liquid or gas. The Atmospheric Scanning Electron Microscope (ASEM) can observe dynamic phenomena in liquid or gas under atmospheric pressure in real time. An electron-permeable window made of pressure-resistant 100 nm-thick silicon nitride (SiN) film, set into the bottom of the open ASEM sample dish, allows an electron beam to be projected from underneath the sample. A detector positioned below captures backscattered electrons. Using the ASEM, we observed the radiation-induced self-organization process of particles, as well as phenomena accompanying volume change, including evaporation-induced crystallization. Using the electrochemical ASEM dish, we observed tree-like electrochemical depositions on the cathode. In silver nitrate solution, we observed silver depositions near the cathode forming incidental internal voids. The heated ASEM dish allowed observation of patterns of contrast in melting and solidifying solder. Finally, to demonstrate its applicability for monitoring and control of industrial processes, silver paste and solder paste were examined at high throughput. High resolution, imaging speed, flexibility, adaptability, and ease of use facilitate the observation of previously difficult-to-image phenomena, and make the ASEM applicable to various fields.     

Some Notes on Stability Problems of Probabilistic Automata

Abstract

The behavior of a probabilistic automaton is essentially characterized by products of matrices selected from a given finite set of stochastic matrices. It is of interest to know under what conditions these matrix products are stable against perturbations of the entries in the matrices.     

Development and field test of the articulated mobile robot T2 Snake-4 for plant disaster prevention

Abstract

In this work, we develop an articulated mobile robot that can move in narrow spaces, climb stairs, gather information, and operate valves for plant disaster prevention. The robot can adopt a tall position using a folding arm and gather information using sensors mounted on the arm. In addition, this paper presents a stair climbing method using a single backward wave. This method enables the robot to climb stairs that have a short tread. The developed robot system is tested in a field test at the World Robot Summit 2018, and the lessons learned in the field test are discussed.     

Questionnaire of cryopreserved allograft valves in Kyushu and Yamaguchi area

Japanese Society of Cryopreserved Thoracic Tissue Implantation was recently set up. Cryopreserved allograft valves are about to pervade in Japan. To clarify the interest, demands and supply of cryopreserved allograft valve in the area of Kyushu and Yamaguchi, we performed questionnaire investigation regarding this issue. Collection rate of this questionnaire was 87.5% (35/40 hospitals). Ninety-seven percent of the hospitals answered that they were interested in cryopreserved allograft. Ninety-four percent of the hospitals answered that they did not ethically hesitate to use cryopreserved allograft. Ninety-one percent of the hospitals hoped to perform cardiac surgery using allograft aortic valve if allograft is available. With respect to securing donors of allograft, two-third of the hospitals did not decide whether they could be involved in obtaining donors of allograft. As the number of the cadaver kidney donors is about 20 per year in the area of Kyushu and Yamaguchi, shortage of donors of allograft valve is anticipated.