MiR-7-5p Is Involved in Ferroptosis Signaling and Radioresistance Thru the Generation of ROS in Radioresistant HeLa and SAS Cell Lines

In cancer therapy, radioresistance or chemoresistance cells are major problems. We established clinically relevant radioresistant (CRR) cells that can survive over 30 days after 2 Gy/day X-ray exposures. These cells also show resistance to anticancer agents and hydrogen peroxide (H₂O₂). We have previously demonstrated that all the CRR cells examined had up-regulated miR-7-5p and after miR-7-5p knockdown, they lost radioresistance. However, the mechanism of losing radioresistance remains to be elucidated. Therefore, we investigated the role of miR-7-5p in radioresistance by knockdown of miR-7-5p using CRR cells. As a result, knockdown of miR-7-5p increased reactive oxygen species (ROS), mitochondrial membrane potential, and intracellular Fe²⁺ amount. Furthermore, miR-7-5p knockdown results in the down-regulation of the iron storage gene expression such as ferritin, up-regulation of the ferroptosis marker ALOX12 gene expression, and increases of Liperfluo amount. H₂O₂ treatment after ALOX12 overexpression led to the enhancement of intracellular H₂O₂ amount and lipid peroxidation. By contrast, miR-7-5p knockdown seemed not to be involved in COX-2 and glycolysis signaling but affected the morphology of CRR cells. These results indicate that miR-7-5p control radioresistance via ROS generation that leads to ferroptosis.     

Water activity-adjusted enzymatic partial hydrolysis of phospholipids to concentrate polyunsaturated fatty acids

Selective partial hydrolyses of egg yolk phospholipid and squid skin phospholipid were carried out. By keeping the water activity (a _w) of Lipozyme IM at an intermediate level, it was easy to concentrate docosahexaenoic acid (DHA). It was also possible to concentrate both DHA and arachidonic acid (AA) simultaneously to a certain level under this a _w range. However, it was impossible to concentrate AA alone when DHA was present. Though there is a limitation in concentrating AA exclusively, the proposed a _w-adjusted hydrolytic reaction is a promising way for preparing phospholipids rich in DHA.     

Investigation of controllable self-organized honeycomb micro-structure

Patterned micro- and nanostructure are of great significance in industrial applications such as electronics, optics and sensors. Microporous honeycomb film of polyhpenylene oxide (PPO) was fabricated as the template via evaporation of solution in carbon bisulfide under humid ambience. The effect of fabrication conditions on patterned microstructure was investigated by self-organization experiments to build quantitative relationship between ambient conditions such as humidity, concentration and honeycomb microstructure (diameter and height), through which the honeycomb film formation can be controlled to self-organize desirable PPO patterned microstructure. Especially, the height of honeycomb was derived from the diameter of honeycomb, and its validity was clarified by morphological comparison between PPO template and PDMS molded structure. Moreover, soft mold experiments were conducted to demonstrate its high efficiency and excellence as an alternative to construct regular micro-pattern.     

Simulation of mechanical properties of epoxy-based chemically amplified resist by coarse-grained molecular dynamics

The mechanical properties of an epoxy-based chemically amplified resists with various cross-linking ratios were simulated using a newly developed coarse-grained molecular dynamics simulation that employs a bead–spring model. Models with the different cross-linking ratios were created in the molecular dynamics calculation step and uniaxial elongation simulations were performed. The results reveal that the simulated elastic modulus of the resist modeled by the Kremer–Grest model with an extended angle bending potential depends on the cross-linking ratio, its dependency exhibits good agreement with that determined by nanoindentation tests.     

Production of thin graphite sheets for a high electrical conductivity film by the mechanical delamination of ternary graphite intercalation compounds

Herein we propose a production scheme for conductive films composed of thin graphite sheets with high crystallinity and polymeric resin. The crystalline graphite sheets were successfully produced from natural graphite powder by solution-phase synthesis of graphite intercalation compounds (GICs), following a wet planetary-ball milling under mild conditions. The shear forces in the milling pot lead to a peeling of graphite flakes. Taking into consideration the interlayer bonding force, the delamination should be preferentially done from the expanded GICs interlayer rather than intrinsic graphite one. Some composite films derived from the phenolic resin and flaky graphite sheets displayed much higher electrical conductivities compared to the film from the feed graphite particles. We also demonstrate the stage structure of synthetic GICs affected the film conductivity. The composite films made from exfoliated products of ground (around stage IV) GICs exhibited high electrical conductivity with a small amount of the graphite sheets.     

Production of finely ground natural graphite particles with high electrical conductivity by controlling the grinding atmosphere

Natural graphite particles with high crystallinity sieved to obtain a particle size range of under 63 μm were ground with a ball mill, under various well-controlled grinding atmospheres such as N₂, O₂, He, H₂, and vacuum. The ratio, X_dif50/X_st50, i.e. between the 50 wt.% Stokes diameter and the 50 wt.% laser diffraction diameter, of the ground particles, was used as an index of the flakiness of the particles. The specific resistance of films composed of the ground graphite particles was systematically measured. The rate of reduction in the size of the particles by grinding was slow under an O₂-rich atmosphere such as 100% O₂ and dry air. On the other hand, it was relatively fast in vacuum, or under an N₂ or He atmosphere, and a gas mixture of 99% N₂ and 1% O₂. The rate of size reduction by grinding under a H₂ atmosphere was intermediate. In our experimental conditions, the flakiness of the ground particles increased with the decrease in the particles’ sizes. The electrical conductivity of the ground particles, however, tended to decrease with the decrease in their sizes. Under the condition that the Stokes diameter of the ground particles remains constant, the electrical conductivity of films made from the ground particles increases with the increase in the flakiness of the particles. It was finally determined from our systematic grinding experiments that small flaky particles, which had a size, X_st of ∼1 μm, with a high electrical conductivity can be produced by grinding in a gas mixture of 99% N₂ and 1% O₂. In this case, the flaky shape of the ground particles was visually confirmed by scanning electron microscopy.     

High oleic acid oil suppresses lung tumorigenesis in mice through the modulation of extracellular signal-regulated kinase cascade

This study was undertaken to estimate the effect of dietary high oleic acid oil (OA) on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis in mice. Diet containing 10% oil was fed to mice through experimental periods. On day 30 after NNK injection (100 mg/kg body weight, i.p.), the treatment increased the level of prostaglandin E₂ (PGE₂) as well as proliferating cell nuclear antigen, a marker of cell proliferation in a high linoleic acid oil (LA)-fed group but not in an OA-fed group. The NNK treatment also induced the activation of an extracellular signal-regulated kinase (Erk) cascade (Erk, Mek and Raf-1) in an LA-fed group. On the other hand, OA feeding abolished the NNK-induced activation of the Erk cascade. In conjugation with these events, OA feeding reduced lung tumor incidence and tumor multiplicity (percentage of mice with tumors) in mice compared with LA feeding at the 20th experimental week. These results suggest that OA suppresses lung tumorigenesis and that this suppression is correlated with the inhibition of PGE₂ production and inactivation of the Erk cascade.     

Uniformly Porous Composites with 3-D Network Structure (UPC-3D) for High-Temperature Filter Applications

Uniformly porous composites with 3-D network structure (UPC-3D) have been recently developed via a pyrolytic reactive sintering process, which takes advantage of the evolved CO₂ gas from a decomposing carbonate source (e.g., dolomite, CaMg(CO₃)₂) and does not require any additional pore-forming agent nor long-time burning-out process. Through liquid formation via LiF doping, strong necks are formed between constituent particles before completion of the pyrolysis of carbonate, resulting in the formation of a strong 3-D network structure. The pore size distribution is very narrow (with typical pore size: ∼1 μm), and the porosity was controllable (∼30–60%) by changing the sintering temperature. This article presents the development details of UPC-3D, and reports the recent findings in CaZrO₃/MgAl₂O₄ system, which will be one of the more promising systems for practical applications.     

Effects of CuO Addition on Electrical Properties of 0.6BiFeO3–0.4(Bi0.5K0.5)TiO3 Lead‐Free Piezoelectric Ceramics

0.6BiFeO₃–0.4(Bi_0.5K_0.5)TiO₃ (0.6BF–0.4BKT) ceramic samples with 0.0–4.0 mol% CuO were prepared by the solid‐state reaction. The CuO addition aided the densification of the samples and slightly increased the lattice constant. The relaxor‐like defuse dielectric peak of 0.6BF–0.4BKT became sharper with increasing the CuO content. Polarization–electric field curve of the undoped 0.6BF–0.4BKT was a pinched loop in the as‐sintered state, while that was a square hysteresis with a large remanent polarization of 48 μC/cm² after the thermal quenching, demonstrating a strong domain wall pinning due to defect dipoles. We found that the CuO addition up to 2.0 mol% facilitates the polarization switching in the as‐sintered samples to increase the remanent polarization and the piezoelectric d₃₃ coefficient. The results of the structural and electrical investigations suggested that the copper ion acts as a donor in 0.6BF–0.4BKT by compensating the potassium vacancy created by the evaporation of K₂O during the calcination and sintering processes.     

Homogeneous Tritylation of Cellulose in A Sulfur Dioxide – Diethylamine – Dimethyl Sulfoxide Medium

The present investigation was undertaken to see if a practical method could be developed for homogeneous tritylation of cellulose in a non-aqueous solvent of cellulose. Our new procedure of tritylation of cellulose can easily be carried out under homogeneous conditions by dissolving cellulose in a sulfur dioxide(SO₂)-diethylamine (DEA)-dimethyl sulfoxide(DMSO) solvent system, one or the non-aqueous cellulose solvents, followed by addition of trityl chloride and pyridine. This new method can avoid the time consuming pretreatment for the decrystallization of cellulose which has been necessary in the traditional procedure and can lower the reaction temperature. IR spectra of the products indicated the formation of trityl cellulose. Measurements of dielectric properties of the products confirmed that trityl groups were selectively introduced at the primary hydroxyl groups in cellulose. This conclusion was also confirmed by a H-NMR study in which the tritylated products was first acetylated, detritylated and then trideuterioacetylated and H-NMR spectra were taken at each stage and examined comparatively.