High-performance carbon counter electrode for dye-sensitized solar cells

Here, we reported that a new carbon electrode prepared with an activated carbon was superior to a Pt sputtered electrode as the counter electrode of dye-sensitized solar cells. The photovoltaic performance was largely influenced by the roughness factor of carbon electrode. The open-circuit voltage increased by about 60 mV using the carbon counter electrode compared to the Pt counter electrode because of positive shift of the formal potential for I₃⁻/I⁻ couple.     

Alignment control of liquid crystals in a 1.0‐μm‐pitch spatial light modulator by lattice‐shaped dielectric wall structure

We achieved uniform liquid crystal (LC) alignment in lattice‐shaped dielectric walls 1 μm in pitch; this is a prerequisite when driving the individual pixels of spatial light modulators, facilitating the development of practical electronic holographic displays with a wide field of view. In lattice‐shaped dielectric walls, LC alignment becomes unstable, particularly on the bottom and the walls; the LC directors tend to align parallel to the walls. To overcome this problem, we created lattice‐shaped walls featuring partition plates that allow uniform LC alignment. When the plates confine LCs to small regions exhibiting spatial anisotropy, the LC elastic effect and wall anchoring forces align the LC directors parallel to the long anisotropic axis. We found that pixels 0.5 μm × 1.0 μm in pitch formed if the partition plates were sufficiently thick to allow shielding of electric field leakage.     

Synthesis of zirconia sphere particles based on gelation of sodium alginate

Zirconia sphere particles were synthesized through the gelation process of Na-alginate, and cermet (ZrO₂-Mo) pellets were fabricated under several conditions. In this process, a zirconia slurry was prepared by mixing oxide powders (ZrO₂, Y₂O₃, Er₂O₃, CeO₂), distilled water and Na-alginate, and subsequently dropped into CaCl₂ solution. As a result, zirconia sphere particles coated with a gelled film were synthesized. The slurry density (zirconia content in slurry) of 30-64 wt.% and Na-alginate concentration of a few% were good for gelation for up to 10 wt.% CaCl₂ solution. Sphere particles with smaller diameter were obtained by dropping slurry with a mechanical vibration. The prolongation of the ball milling time for mixture of oxide powders was effective to increase the sintered density of zirconia sphere particles, especially for higher CeO₂ concentration. The dense cermet pellets were fabricated for max. 50% volume ratio of zirconia phase for Mo matrix using zirconia particles covered with Mo powder by a rotating granulation method.     

Re-evaluation of the phase relationship between plutonium and zirconium dioxides

The phase relationship between ZrO₂ and PuO₂ was examined in a low PuO₂ content region, from 3.1 to 11.2 mol% PuO₂, at temperatures between 1273 K and 1473 K, by high temperature X-ray diffractometry. The measurements were carried out in air. At 1273 K, the samples in this composition range consisted of two phases, monoclinic and cubic. Another phase, tetragonal, was observed at 1373 K. The low temperature monoclinic phase disappeared at 1473 K. It was confirmed that the monoclinic phase disappears around 1463 K; the disappearance temperature does not depend on the composition of the sample. It was, thus, inferred that there should be a eutectoid line in the phase diagram. Though the eutectoid point is not clear, the PuO₂ content at the point should be less than 3.1 mol%.     

Unilateral labyrinthectomy downregulates glutamate receptor delta-2 expression in the rat vestibulocerebellum

Subcortical damage in neonates often has more severe consequences than in adults. Unilateral electrolytic hippocampal lesions in adult rats typically result in transient memory deficits, whereas neonatal lesions cause lasting memory impairments. We hypothesized that unilateral lesions made at birth may affect synaptic physiology in the contralateral hippocampus. Consequently, the ability to sustain long-term potentiation (LTP), a form of synaptic plasticity believed to underlie certain forms of memory, was compared between slices from the remaining hippocampus of rats lesioned as newborns and as adults. Initial studies showed that a train of 10 stimulation bursts patterned after the hippocampal theta rhythm produced robust and stable LTP both in slices from controls and rats lesioned at birth. However, a theta burst pattern of stimulation closer to intrinsic physiology (five burst pairs separated by 30 s each), induced significantly less LTP in slices from rats lesioned at birth compared to those from controls and rats lesioned as adults. To investigate possible mechanisms underlying the deficit, the degree of paired-pulse facilitation (PPF) as well as the amount of depolarization occurring between two successive theta bursts were analyzed. The lesion did not detectably change PPF characteristics, suggesting that presynaptic mechanisms are normal. However, the extent to which a burst response was increased by a prior burst was significantly diminished in slices from rats lesioned at birth compared to those from controls and rats lesioned as adults, indicating that postsynaptic factors involved in the initial triggering events of LTP are affected by the lesion. Reduced ability to sustain LTP in the remaining hippocampus may contribute to impaired memory function after unilateral neonatal hippocampal lesion.     

Minimization of Friction at Various Speeds Using Autonomous Viscosity Control of Nematic Liquid Crystal

To demonstrate the concept of the smart lubrication system using liquid crystal (LC) lubricant proposed by Nakano (Tribol Lett 14:17–24, 2003), the following three types of tests were performed: (1) film thickness measurements in pure rolling contacts, (2) friction coefficient measurements in rolling–sliding contacts, and (3) molecular orientation measurements in stationary cells. In all of these types of tests, a nematic LC [4-pentyl-4′-cyanobiphenyl (5CB)] and a carboxylic acid [hexadecanoic acid (HDA)] were used as the base fluid and the additive, respectively. The results of these tests confirm the following mechanism. First, surface films of the HDA additive that spontaneously adsorb onto contact surfaces induce surface anchoring, which has the effect of making 5CB molecules align themselves perpendicular to the surfaces, competing with the flow alignment of 5CB molecules and inducing an increase in the apparent viscosity of 5CB with decreasing entrainment speed. This increase in the apparent viscosity generates a constant friction coefficient region in the Stribeck curve on the left side of the minimum friction coefficient point, resulting in the minimization of friction at various speeds.     

Fine-tuned,molecular-composite,organosilica membranes for highly efficient propylene/propane separation via suitable pore size

Fine-tuned, molecular-composite, organosilica membranes were fabricated via the co-condensation of organosilica precursors bis(triethoxysilyl)acetylene (BTESA) and bis(triethoxysilyl)benzene (BTESB). Fourier transform infrared and UV–vis spectra confirmed the co-condensation behaviors of BTESA and BTESB. The evolution of the network structure indicated that the incorporated BTESB decreased the membrane pore size, which was determined by a modified gas translation model according to the steric effect of the phenyl groups. The incorporation of BTESB to BTESA finely tuned the membrane structure and endowed the resultant composite membrane with improved separation properties. The BTESAB 9:1 membrane (molar ratio of BTESA/BTESB was 9:1) exhibited high C₃H₆ permeance at 4.5 × 10⁻⁸ mol m⁻² s⁻¹ Pa⁻¹ and a C₃H₆/C₃H₈ permeance ratio of 33 at 50°C. One of the most important developments of this study involved clearly defining the relationship between membrane pore size and C₃H₆/C₃H₈ separation performance for organosilica membranes in single and binary separation systems.     

Incorporating a Polyethyleneglycol Linker to Enhance the Hydrophilicity of Mitochondria-Targeted Triphenylphosphonium Constructs

The targeting of bioactive molecules and probes to mitochondria can be achieved by coupling to the lipophilic triphenyl phosphonium (TPP) cation, which accumulates several hundred-fold within mitochondria in response to the mitochondrial membrane potential (Δψ_m). Typically, a simple alkane links the TPP to its “cargo”, increasing overall hydrophobicity. As it would be beneficial to enhance the water solubility of mitochondria-targeted compounds we explored the effects of replacing the alkyl linker with a polyethylene glycol (PEG). We found that the use of PEG led to compounds that were readily taken up by isolated mitochondria and by mitochondria inside cells. Within mitochondria the PEG linker greatly decreased adsorption of the TPP constructs to the matrix-facing face of the mitochondrial inner membrane. These findings will allow the distribution of mitochondria-targeted TPP compounds within mitochondria to be fine-tuned.     

Metastatic Voyage of Ovarian Cancer Cells in Ascites with the Assistance of Various Cellular Components

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy and has a unique metastatic route using ascites, known as the transcoelomic root. However, studies on ascites and contained cellular components have not yet been sufficiently clarified. In this review, we focus on the significance of accumulating ascites, contained EOC cells in the form of spheroids, and interaction with non-malignant host cells. To become resistant against anoikis, EOC cells form spheroids in ascites, where epithelial-to-mesenchymal transition stimulated by transforming growth factor-β can be a key pathway. As spheroids form, EOC cells are also gaining the ability to attach and invade the peritoneum to induce intraperitoneal metastasis, as well as resistance to conventional chemotherapy. Recently, accumulating evidence suggests that EOC spheroids in ascites are composed of not only cancer cells, but also non-malignant cells existing with higher abundance than EOC cells in ascites, including macrophages, mesothelial cells, and lymphocytes. Moreover, hetero-cellular spheroids are demonstrated to form more aggregated spheroids and have higher adhesion ability for the mesothelial layer. To improve the poor prognosis, we need to elucidate the mechanisms of spheroid formation and interactions with non-malignant cells in ascites that are a unique tumor microenvironment for EOC.