Cyanidin 3-O-arabinoside suppresses DHT-induced dermal papilla cell senescence by modulating p38-dependent ER-mitochondria contacts.

BACKGROUND: Androgenetic alopecia (AGA) is a genetic disorder caused by dihydrotestosterone (DHT), accompanied by the senescence of androgen-sensitive dermal papilla cells (DPCs) located in the base of hair follicles. DHT causes DPC senescence in AGA through mitochondrial dysfunction. However, the mechanism of this pathogenesis remains unknown. In this study, we investigated the protective role of cyanidins on DHT-induced mitochondrial dysfunction and DPC senescence and the regulatory mechanism involved. METHODS: DPCs were used to investigate the effect of DHT on mitochondrial dysfunction with MitoSOX and Rhod-2 staining. Senescence-associated ß-galactosidase activity assay was performed to examine the involvement of membrane AR-mediated signaling in DHT-induced DPC senescence. AGA mice model was used to study the cyanidins on DHT-induced hair growth deceleration. RESULTS: Cyanidin 3-O-arabinoside (C3A) effectively decreased DHT-induced mtROS accumulation in DPCs, and C3A reversed the DHT-induced DPC senescence. Excessive mitochondrial calcium accumulation was blocked by C3A. C3A inhibited p38-mediated voltage-dependent anion channel 1 (VDAC1) expression that contributes to mitochondria-associated ER membrane (MAM) formation and transfer of calcium via VDAC1-IP3R1 interactions. DHT-induced MAM formation resulted in increase of DPC senescence. In AGA mice models, C3A restored DHT-induced hair growth deceleration, which activated hair follicle stem cell proliferation. CONCLUSIONS: C3A is a promising natural compound for AGA treatments against DHT-induced DPC senescence through reduction of MAM formation and mitochondrial dysfunction.

Genotypic, phenotypic, and pathogenic characterization of the soil isolated Acinetobacter courvalinii.

Most of the human gene homologs are found in Caenorhabditis elegans. As a wide variety of micro-organisms present in the environment is pathogens, so, C. elegans could be a useful model to track future infectious disease. With this knowledge, in this study, we isolated Acinetobacter courvalinii from the soil and characterized its pathogenicity for the first time. For the isolation, we used Glucose-Yeast extract-Ethanol-Calcium carbonate medium. To this aim, we evaluated the resistivity of bacteria against several stressful microenvironments. As we observed, A. courvalinii JP_A1001 shown highly tolerance against the acidic environment (pH 3-7), resistant against up to 0.2% of phenol content, and survived in the medium supplemented with 0.3% of bile salt. In addition, the bacteria were also resistant against several antibiotics showing the property of multidrug-resistant bacteria. Moreover, the isolated bacteria have shown the biofilm formation ability within 60 h. Further, we found that incubation of C. elegans with A. courvalinii JP_A1001 decreased the body movement and increased the free radical generation which remarkably influenced the life expectancy of C. elegans compared to E. coli OP50. Therefore, we concluded that A. courvalinii JP_A1001 found in the soil could be a future threat as a pathogen to public health.

Self assembled growth of GaSb nano triangles on GaN/sapphire substrate.

Self-assembled GaSb nano structures were grown on GaN/sapphire. GaSb nano triangles as well as quantum dots were obtained under controlled growth conditions. Nano triangles were grown at 580 degrees C due to the growth rate anisotropy among the (1100) planes. The size of nano triangle was 87 nm in width, 5 nm in height, and the density was 5 x 10(8) cm(-2), when the growth time was 30 s. This is the first report on the self assembled growth of nano triangles within a highly strained material system.

Surface passivation of high density InGaN/GaN nanorods fabricated by reactive ion etching.

High density GaN nanorods containing InGaN quantum disks (QD's) were fabricated by inductively coupled plasma reactive ion etching (RIE) with self-assembled nano masks. Optical properties of the QD were severely degraded because of the damage on etched sidewalls during the RIE. However, after surface treatment with (NH4)2S, the QD showed improved photoluminescence. This result suggests that surface damage of GaN nanostructure during the dry etching can be passivated by sulfur atoms.

Uniform and reproducible barrier layer removal of porous anodic alumina membrane.

A method for the fabrication of porous anodic alumina (PAA) membrane without bottom barrier layer on Al substrate is described. In this method, two-step anodizing followed by a barrier thinning process at the end of the second anodization was used to prepare wide range highly-ordered PAA membrane with a thin barrier layer. Finally, cathodic polarization and pore widening processes were combined to remove the barrier layer completely between the oxide film and Al substrate. Scanning electron microscope (SEM) was used to characterize the morphology and structure of the PAA membrane. From the SEM images, the PAA membrane prepared with the assistance of cathodic polarization showed more homogeneous pore diameters and pore wall quality than that made by pore widening only. In addition, the barrier layer was removed completely with 7.5 min of cathodic polarization and 70 min of pore widening without corrosion in the Al substrate. It was possible to control the pore diameter without any damage to the PAA template from 70 to 90 nm. The fabricated PAA template can be applied to the growth of ordered nanowires, nanorods, nanotubes, and similar structures.

Reduction of interpore distance of anodized aluminum oxide nano pattern by mixed H3PO4:H2SO4 electrolyte.

A self-formed and ordered anodized aluminum oxide (AAO) nano pattern has generated considerable interest in both scientific research and commercial application. However, the interpore distance obtainable by AAO is limited by 40-500 nm depending on electrolyte and anodizing voltage. It's believed that below-30 nm AAO pattern is a key technology in the fabrication semiconductor nano structures with enhanced quantum confinement effect, so we worked on the reduction of interpore distance of AAO with a novel electrolyte. AAO nano patterns were fabricated with mixed H2SO4 and H3PO4 as an electrolyte for various voltages and temperatures. The interpore distance and pore diameter of AAO were decreased with reduced anodizing voltage. As a result, an AAO nano pattern with the interpore distance of 27 nm and the pore diameter of 7 nm was obtained. This is the smallest pattern, as long as we know, reported till now with AAO technique. The fabricated AAO pattern could be utilized for uniform and high density quantum dots with increased quantum effect.

Parallel Aligned Mesopore Arrays in Pyramidal-Shaped Gallium Nitride and Their Photocatalytic Applications.

Parallel aligned mesopore arrays in pyramidal-shaped GaN are fabricated by using an electrochemical anodic etching technique, followed by inductively coupled plasma etching assisted by SiO2 nanosphere lithography, and used as a promising photoelectrode for solar water oxidation. The parallel alignment of the pores of several tens of micrometers scale in length is achieved by the low applied voltage and prepattern guided anodization. The dry etching of single-layer SiO2 nanosphere-coated GaN produces a pyramidal shape of the GaN, making the pores open at both sides and shortening the escape path of evolved gas bubbles produced inside pores during the water oxidation. The absorption spectra show that the light absorption in the UV range is ∼93% and that there is a red shift in the absorption edge by 30 nm, compared with the flat GaN. It also shows a remarkable enhancement in the photocurrent density by 5.3 times, compared with flat GaN. Further enhancement (∼40%) by the deposition of Ni was observed due to the generation of an electric field, which increases the charge separation ratio.

Visible Color Tunable Emission in Three-Dimensional Light Emitting Diodes by MgO Passivation of Pyramid Tip.

We demonstrated visible color tunable three-dimensional (3D) pyramidal light emitting diodes by depositing the MgO on and near the tip of the pyramid as an insulating layer. Here, we show that the degradation of the materials (i.e., p-GaN) crystallinity and the built-in electric field due to the nanoscale geometry of the tip region is responsible for the large leakage current observed in LEDs. Confocal scanning electroluminescence microscopy images clearly showed that the intensity of the light emitted out of the side facet of the pyramid is much higher than that of the light extracted out of the tip surface, indicating that the MgO layer prohibited the carrier injection to the MQWs layer, suppressing the leakage occurring at or near the tip region of the pyramids. The color range of the LEDs can be also tuned by using the MgO layer, a blue-shift by 10.3 nm in the wavelength. This technique is simple and scalable, providing a promising solution for developing 3D pyramidal LEDs with low leakage current and controllable light emission.

Structural Evolution of Chemically-Driven RuO2 Nanowires and 3-Dimensional Design for Photo-Catalytic Applications.

Growth mechanism of chemically-driven RuO2 nanowires is explored and used to fabricate three-dimensional RuO2 branched Au-TiO2 nanowire electrodes for the photostable solar water oxidation. For the real time structural evolution during the nanowire growth, the amorphous RuO2 precursors (Ru(OH)3 · H2O) are heated at 180 (°)C, producing the RuO2 nanoparticles with the tetragonal crystallographic structure and Ru enriched amorphous phases, observed through the in-situ synchrotron x-ray diffraction and the high-resolution transmission electron microscope images. Growth then proceeds by Ru diffusion to the nanoparticles, followed by the diffusion to the growing surface of the nanowire in oxygen ambient, supported by the nucleation theory. The RuO2 branched Au-TiO2 nanowire arrays shows a remarkable enhancement in the photocurrent density by approximately 60% and 200%, in the UV-visible and Visible region, respectively, compared with pristine TiO2 nanowires. Furthermore, there is no significant decrease in the device's photoconductance with UV-visible illumination during 1 day, making it possible to produce oxygen gas without the loss of the photoactvity.