Initial phase and frequency modulations of pumping a playground swing.

The playground swing is a dynamic, coupled oscillator system consisting of the swing as an object and a human as the swinger. Here, we propose a model for capturing the effect of the initial phase of natural upper body motion on the continuous pumping of a swing and validate this model from the motion data of ten participants pumping swings of three different swing chain lengths. Our model predicts that the swing pumps the most if the phase of maximum lean back, which we call the initial phase, occurs when the swing is at a vertical (midpoint) position and moving forward when the amplitude is small.

Quasi-static 3D structure of graphene ripple measured using aberration-corrected TEM.

Free-standing graphene has a three-dimensional (3D) structure, called a ripple, rather than a perfect two-dimensional (2D) crystal. Since theoretical calculations suggest that a ripple strongly influences various fundamental physicochemical properties of graphene, it is important to clarify the ripple structure quantitatively in experiments. This paper proposes a new method of measuring the 3D atomic structure of a ripple by using aberration-corrected transmission electron microscopy (TEM).

Contribution of Ultra-Fine Bubbles to Promoting Effect on Propane Hydrate Formation.

To investigate experimentally how ultra-fine bubbles (UFBs) may promote hydrate formation, we examined the formation of propane (CH) hydrate from UFB-infused water solution using two preparation methods. In one method, we used CH-hydrate dissociated water, and in the other, CH-UFB-included water prepared with a generator. In both solutions, the initial conditions had a UFB number density of up to 10 mL.

Trehalose uptake and dehydration effects on the cryoprotection of CHO-K1 cells expressing TRET1.

Chinese hamster ovary cells (CHO-K1 cells) in which the trehalose transporter (TRET1) is expressed can have greater cryoprotection than ordinary CHO-K1 cells. This study examines the uptake characteristics of trehalose into cells via TRET1 and determines the influence of intracellular trehalose on the freeze-thaw viabilities. In our experiments, the intracellular trehalose concentration is controlled by the extracellular trehalose concentration and the immersion time in a freezing solution.

Xenon pressure dependence on the synchronized burst inhibition of rat cortical neuronal network cultured on multi-electrode arrays.

Mature rat cortical neuronal networks cultured on multi-electrode arrays (MEAs) are known to show spontaneous synchronized bursts accompanied by independent single spikes. The spontaneous synchronized bursts can be inhibited by Xe gas. In this study, we adjust the Xe gas pressure to control the amount of Xe in a neuron-cultured MEA medium.

Intracellular trehalose via transporter TRET1 as a method to cryoprotect CHO-K1 cells.

Trehalose is a promising natural cryoprotectant, but its cryoprotective effect is limited due to difficulties in transmembrane transport. Thus, expressing the trehalose transporter TRET1 on various mammalian cells may yield more trehalose applications. In this study, we ran comparative cryopreservation experiments between the TRET1-expressing CHO-K1 cells (CHO-TRET1) and the CHO-K1 cells transfected with an empty vector (CHO-vector).

Effect of NaCl on the Lifetime of Micro- and Nanobubbles.

Micro- and nanobubbles (MNBs) are potentially useful for industrial applications such as the purification of wastewater and the promotion of physiological activities of living organisms. To develop such applications, we should understand their properties and behavior, such as their lifetime and their number density in solution. In the present study, we observed oxygen MNBs distributed in an electrolyte (NaCl) solution using a transmission electron microscope to analyze samples made with the freeze-fracture replica method.

K-means clustering for support construction in diffractive imaging.

A method for constructing an object support based on K-means clustering of the object-intensity distribution is newly presented in diffractive imaging. This releases the adjustment of unknown parameters in the support construction, and it is well incorporated with the Gerchberg and Saxton diagram. A simple numerical simulation reveals that the proposed method is effective for dynamically constructing the support without an initial prior support.

Joint action syntax in Japanese martial arts.

Participation in interpersonal competitions, such as fencing or Japanese martial arts, requires players to make instantaneous decisions and execute appropriate motor behaviors in response to various situations. Such actions can be understood as complex phenomena emerging from simple principles. We examined the intentional switching dynamics associated with continuous movement during interpersonal competition in terms of their emergence from a simple syntax.

Measurement of saturation processes in glutamatergic and GABAergic synapse densities during long-term development of cultured rat cortical networks.

The aim of this study was to clarify the saturation processes of excitatory and inhibitory synapse densities during the long-term development of cultured neuronal networks. For this purpose, we performed a long-term culture of rat cortical cells for 35 days in vitro (DIV). During this culture period, we labeled glutamatergic and GABAergic synapses separately using antibodies against vesicular glutamate transporter 1 (VGluT1) and vesicular transporter of γ-aminobutyric acid (VGAT).

Neuronal cell patterning on a multi-electrode array for a network analysis platform.

We studied neuronal cell patterning on a commercial multi-electrode array (MEA). We investigated the surface chemical modification of MEA in order to immobilize Poly-D-lysine (PDL) and then to pattern PDL with a photolithographic method using vacuum ultraviolet light (VUV). We have clarified that the PDL layer was not fully decomposed but was partially fragmented by short-time irradiation with VUV, resulting in a change in the cell adhesiveness of the PDL.

Dissociation of the insulin receptor from caveolae during TNFα-induced insulin resistance and its recovery by D-PDMP.

Previously, we demonstrated that an inhibitor of ganglioside biosynthesis, d-PDMP, could restore impaired insulin signaling in tumor necrosis factor α (TNFα)-treated adipocytes by blocking the increase of GM3 ganglioside. Here, we analyzed the interaction between insulin receptor (IR) and GM3 in the plasma membranes using immunoelectron microscopy. In normal adipocytes, most GM3 molecules localized at planar and non-caveolar regions.

Optimal temperature range for low-temperature preservation of dissociated neonatal rat cardiomyocytes.

The increase in demand for primary cardiomyocytes necessitates advanced methods for their stable supply. In this study, we investigated the optimal temperature range for preserving dissociated cardiomyocytes for 72 h while maintaining their normal growth and beating functions. Neonatal rat cardiomyocytes dissociated by collagenase and suspended in the culture medium were preserved at temperatures from -2 to 35°C for 72 h.

Cell patterning using a template of microstructured organosilane layer fabricated by vacuum ultraviolet light lithography.

Micropatterning techniques have become increasingly important in cellular biology. Cell patterning is achieved by various methods. Photolithography is one of the most popular methods, and several light sources (e.

Spherical shell structure of distribution of images reconstructed by diffractive imaging.

Image reconstruction from Fourier intensity through phase retrieval was investigated when the intensity was contaminated with Poisson noise. Although different initial conditions and/or the instability of the iterative phase retrieval process led to different reconstructed images, we found that the distribution of the resulting images in both the object and Fourier spaces formed spherical shell structures. Averaging of the images over the distribution corresponds to the position of the image at the sphere center.

Contrary effects of octopamine receptor ligands on behavioral and neuronal changes in locomotion of lymnaea.

The pond snail Lymnaea stagnalis moves along the sides and bottom of an aquarium, but it can also glide upside down on its back below the water's surface. We have termed these two forms of locomotion "standard locomotion" and "upside-down gliding," respectively. Previous studies showed that standard locomotion is produced by both cilia activity on the foot and peristaltic contraction of the foot muscles, whereas upside-down gliding is mainly caused by cilia activity.

10-kV diffractive imaging using newly developed electron diffraction microscope.

A new electron diffraction microscope based on a conventional scanning electron microscope (SEM), for obtaining atomic-level resolution images without causing serious damage to the specimen, has been developed. This microscope in the relatively low-voltage region makes it possible to observe specimens at suitable resolution and record diffraction patterns. Using the microscope we accomplished 10-kV diffractive imaging with the iterative phase retrieval and reconstructed the structure of a multi-wall carbon nanotube with its finest feature corresponding to 0.

Shrinking and development of lipid droplets in adipocytes during catecholamine-induced lipolysis.

Time-lapse observation of adipocytes during catecholamine-induced lipolysis clearly shows that shrinking of existing lipid droplets (LDs) occurs in some adipocytes and that small LDs are newly developed in almost all cells. Immunofluorescence imaging reveals that activation and localization of hormone-sensitive lipase (HSL) on the surface of LDs, which are required for conferring maximal lipolysis, are necessary for the shrinking of the LDs. However, not all adipocytes in which phosphorylated HSL is localized on LDs exhibit shrinking of LDs.

Upside-down gliding of Lymnaea.

The pond snail Lymnaea stagnalis can often be observed moving upside down on its back just below the surface of the water. We have termed this form of movement "upside-down gliding." To elucidate the mechanism of this locomotion, we performed a series of experiments involving behavioral analyses and microscopic observations.

Maximum entropy method for diffractive imaging.

Based on the minimization of the Lagrange formula, which is composed of two kinds of information measure, the maximum entropy method (MEM) is derived for diffractive imaging contaminated by quantum noise. This gives a suitable object corresponding to the maximum entropy principle with an iterative procedure. The MEM-based iterative phase retrieval algorithm with the initial process of the hybrid input-output (HIO-MEM) is presented, and a simple numerical example shows that the algorithm is effective for Poisson noise added to Fourier intensity.

Anomaly of fractal dimensions observed in stochastically switched systems.

We studied an anomaly in fractal dimensions measured from the attractors of dynamical systems driven by stochastically switched inputs. We calculated the dimensions for different switching time lengths in two-dimensional linear dynamical systems, and found that changes in the dimensions due to the switching time length had a singular point when the system matrix had two different real eigenvalues. Using partial dimensions along each eigenvector, we explicitly derived a generalized dimension D(q) and a multifractal spectrum f(alpha) to explain this anomalous property.

Temporal and spatial variations of lipid droplets during adipocyte division and differentiation.

By capturing time-lapse images of primary stromal-vascular cells (SVCs) derived from rat mesenteric adipose tissue, we revealed temporal and spatial variations of lipid droplets (LDs) in individual SVCs during adipocyte differentiation. Numerous small LDs (a few micrometers in diameter) appeared in the perinuclear region at an early stage of differentiation; subsequently, several LDs grew to more than 10 microm in diameter and occupied the cytoplasm. We have developed a method for the fluorescence staining of LDs in living adipocytes.