Design and fabrication of a dielectrophoresis-based cell-positioning and cell-culture device for construction of cell networks

In this paper, we describe the design and fabrication of a dielectrophoresis (DEP)-based cell-positioning and cell-culture device for the construction of cell networks. This device enables both individual cell positioning and cell culture. Titanium electrodes were fabricated by deposition. Furthermore, microchambers and microchannels composed of SU-8, which is a negative photoresist, were used to carry out cell culture and enable cell differentiation. Using our device, N1E-115 cells were individually positioned in the microchambers, and the positioning yield was 45%. After positioning, the cells could be continuously cultured in the microchambers. Furthermore, the cells differentiated, and their neurites extended through the microchannels after cultivation for several days. These results indicate that our device greatly increases the prospects for individual cell positioning and can be used to construct cell networks that have several applications in the medical field, for example, in drug screening.     

An extension of the Uchiyama theorem and its application to composition operators which preserve BMO

Uchiyama constructed certain extremal BMO functions on Euclidean spaces which show that the John-Nirenberg estimate is in some sense remarkably precise. We extend his result to the case of general subdomains of Euclidean spaces. Also, as an application, we characterize Lebesgue measurable maps between general subdomains of Euclidean spaces which preserve BMO. To the memory of Professor Nobuyuki Suita     

A generating function for sums of multiple zeta values and its applications

A generating function for specified sums of multiple zeta values is defined and a differential equation that characterizes this function is given. As applications, some relations for multiple zeta values over the field of rational numbers are discussed.

     

Optically driven actuators using poly(vinylidene difluoride)

Optically driven actuators have a feature of a non-contact method supplied by light energy. A new method is proposed with three poly(vinylidene difluoride) (PVDF) cantilevers as the legs and a polymer film as the body. The PVDF cantilevers are coated with silver on one surface. When one side of the cantilever is irradiated by a laser beam, an electric field is produced along a cross-section of the cantilever by the pyroelectric effect and a mechanical displacement occurs by the piezoelectric effect. Its response time and its generated force are measured experimentally. Two types of optically driven actuators using PVDF film are proposed to move using different characteristics.     

Pulsed laser deposition of pure fluoroapatite film without OH groups

The relation between O₂ pressure and composition in the pulsed‐laser deposition of fluoroapatite was investigated using both on‐axis and off‐axis methods to determine the optimal conditions for obtaining a pure fluoroapatite film without OH groups. Through this, it was found that an O₂ pressure of 10 Pa, combined with an off‐axis method, results in P/Ca and F/Ca values (0.6 and 0.2, respectively) that match closely with a stoichiometric composition of Ca₁₀(PO₄)₆F₂. Fourier transform infrared spectroscopy analysis confirmed that this optimized film was almost pure fluoroapatite, with no evidence of any OH groups originating from hydroxyapatite. X‐ray diffraction also revealed that this fluoroapatite film crystallizes with a c‐axis orientation perpendicular to its surface.     

First direct visualization of spillover species emitted from pt nanoparticles

We studied the methanol adsorption behavior of Pt nanoparticles that were vacuum-deposited on a TiO(2)(110) surface at room temperature by using an ultrahigh vacuum (UHV) scanning tunneling microscope (STM). A large number of bright spots were observed on fivefold-coordinated Ti (Ti(5c)) rows of the TiO(2)(110) surface after exposure of the Pt/TiO(2)(110) to methanol vapor. We assigned the bright spots to methoxy species. These were mobile and were found to hop along the Ti(5c) rows. In situ time-resolved STM observations of the formation and migration of the bright spots on the Pt/TiO(2)(110) were carried out in the presence of methanol. The bright spots were produced at the periphery of the Pt nanoparticles and migrated to the substrate Ti(5c) rows. We discuss the spillover process and behavior of the methoxy species on the Pt/TiO(2)(110).     

Copper-Free Sonogashira coupling in water with an amphiphilic resin-supported palladium complex

The palladium-catalyzed coupling reaction of aryl halides with terminal alkynes, the Sonogashira coupling, took place in water under copper-free conditions by use of an amphiphilic polystyrene-poly(ethylene glycol) (PS-PEG) resin-supported palladium-phosphine complex to give the corresponding aryl-substituted alkynes in high yields. The PS-PEG resin-supported palladium catalyst was recovered by simple filtration and reused four times without any loss of catalytic activity.