Color tunability of nanophosphors by changing cations for solid-state lighting

X₃MgSi₂O₈: Eu²⁺, Mn²⁺ (X=Ba, Sr, Ca) phosphors with the mean particle size of 200 nm and the spherical shape are synthesized through combustion method. They show three emission colors under near-ultraviolet light: the blue and green colors from Eu²⁺ ions and the red color from Mn²⁺ ions. Three emission bands show the different emission colors with changing X²⁺ cations. These color shifts are discussed in terms of two competing factors of the crystal field strength and the covalency. These phosphors with maximum excitation of around 375 nm can be applied as color-tunable phosphors for white-light-emitting diode based on ultraviolet/phosphor technology.     

Green-emissive transparent BaSi2O5:Eu film phosphor on quartz glass created by a sputtering thermal diffusion process

Eu²⁺-doped BaSi₂O₅ film phosphors on quartz substrates are fabricated by radio-frequency magnetron sputtering thermal diffusion. The BaSi₂O₅: Eu²⁺ phosphor crystals have some preferred orientations that are lattice-spacing matched with the crystallized β- SiO₂ crystals, and they show pore and grain boundary-free morphology with a rod-like shape fused into the crystallized β- SiO₂ crystals. The BaSi₂O₅: Eu²⁺ film phosphor has a high transparency, with a transmittance of about 30% in visible light. The BaSi₂O₅: Eu²⁺ film phosphor shows 510 nm green emission from the f–d transition of the Eu²⁺ ions, and in particular the best sample shows a green photoluminescence brightness of about 5% of a BaSi₂O₅: Eu²⁺ powder phosphor screen. These excellences in optical properties can be explained by less optical scattering at pores or grain boundaries, and less reflection at the continuously index-changed interface.     

Flow Dynamics of \hbox {CO}_{2}/brine at the Interface Between the Storage Formation and Sealing Units in a Multi-layered Model

Pressure distribution and \(\hbox {CO}_{2}\) plume migration are two major interests in \(\hbox {CO}_{2}\) geologic storage as they determine the injectivity and storage capacity. In this study, we adopted a three-layer model comprising a storage formation and the over- and underlying seals and determined three distinct flow regions based on the vertical flux exchange of \(\hbox {CO}_{2}\) and native brine. Regions 1 and 2 showed \(\hbox {CO}_{2}\) flowing from the storage formation to adjacent seals with counter-flowing brine. The characteristics of these fluxes in Region 1 were governed by permeability change due to salt precipitation whereas buoyancy force controlled the flux pattern in Region 2. Region 3 showed brine flowing from storage formation toward the over- and underlying seals, which enabled the displaced brine to escape from the storage formation and make room for \(\hbox {CO}_{2}\) to store as well as reduce the pressure build-up. In the multi-layered model, the counter-flowing brine in flow Region 1 resulted in localized salt precipitation at the upper and lower boundary of storage formation. We assessed the bottom-hole pressure and \(\hbox {CO}_{2}\) mass in caprock with respect to reservoir size. While the formation thickness influenced the bottom-hole pressure in the early stage of injection, the horizontal extension of the reservoir was more influential to pressure build-up during the injection period, and to the stabilized pressure during the post-injection period. The \(\hbox {CO}_{2}\) mass in caprock gently increased during the injection period as well as during the post-injection period and reached about 4–5 % of injected \(\hbox {CO}_{2}\) . The percentage of escaped brine from the storage formation ranged from 80–100 % of the \(\hbox {CO}_{2}\) mass stored in the storage formation depending on the reservoir scale.     

Multicentre hydrogen bonds in a 2:1 aryl­sulfonyl­imidazol­one ­hydro­chloride salt

The title compound, (S)‐(+)‐4‐[5‐(2‐oxo‐4,5‐di­hydro­imidazol‐1‐yl­sulfonyl)­indolin‐1‐yl­carbonyl]­anilinium chloride (S)‐(+)‐1‐[1‐(4‐amino­benzoyl)­indoline‐5‐sulfonyl]‐4‐phenyl‐4,5‐di­hydro­imidazol‐2‐one, C₂₄H₂₃N₄O₄S⁺·Cl^?·C₂₄H₂₂N₄O₄S, crystallizes in space group C2 from a CH₃OH/CH₂Cl₂ solution. In the crystal structure, there are two different conformers with their terminal C₆ aromatic rings mutually oriented at angles of 67.69 (14) and 61.16 (15)°. The distances of the terminal N atoms (of the two conformers) from the chloride ion are 3.110 (4) and 3.502 (4) Å. There are eight distinct hydrogen bonds, i.e. four N—H?Cl, three N—H?O and one N—H?N, with one N—H group involved in a bifurcated hydrogen bond with two acceptors sharing the H atom. C—H?O contacts assist in the overall hydrogen‐bonding process.     

Identification of Novel Rab27a/Melanophilin Blockers by Pharmacophore-Based Virtual Screening

Melanocytes are unique cells that produce specific melanin-containing intracellular organelles called melanosomes. Melanosomes are transported from the perinuclear area of melanocytes toward the plasma membrane as they become more melanized in order to increase skin pigmentation. In this vesicular trafficking of melanosomes, Rab27a, melanophilin, and myosin Va play crucial roles in linking melanosomes to actin-based motors. To identify novel compounds to inhibit binding interface between Rab27a and melanophilin, a pharmacophore model was built based on a modeled 3D structure of the protein complex that describes the essential binding residues in the intermolecular interaction. A pharmacophore model was employed to screen a chemical library database. Finally, 25 virtual hits were selected for biological evaluations. The biological activities of 11 analogues were evaluated in a second assay. Two compounds were identified as having concentration-dependent inhibitory activity. By analyzing structure–activity relationships of derivatives of BMD-20, two hydroxyl functional groups were found to be critical for blocking the intermolecular binding between Rab27a and melanophilin.     

Application of QPLEXTM biomarkers in cognitively normal individuals across a broad age range and diverse regions with cerebral amyloid deposition

The deposition of beta-amyloid (Aβ) in the brain precedes the onset of symptoms such as cognitive impairment in Alzheimer’s disease (AD); therefore, the early detection of Aβ accumulation is crucial. We previously reported the applicability of the QPLEX^TM Alz plus assay kit for the prescreening of Aβ accumulation. Here, we tested the specific application of the kit in a large cohort of cognitively normal (CN) individuals of varying ages for the early detection of Aβ accumulation. We included a total of 221 CN participants with or without brain Aβ. The QPLEX^TM biomarkers were characterized based on age groups (1^st–3^rd tertile) and across various brain regions with cerebral amyloid deposition. The 3^rd tertile group (>65 years) was found to be the most suitable age group for the application of our assay kit. Receiver operating characteristic curve analysis showed that the area under the curve (AUC, discrimination power) was 0.878 with 69.7% sensitivity and 98.4% specificity in the 3^rd tertile group. Additionally, specific correlations between biomarkers and cerebral amyloid deposition in four different brain regions revealed an overall correlation with general amyloid deposition, consistent with previous findings. Furthermore, the combinational panel with plasma Aβ1–42 levels maximized the discrimination efficiency and achieved an AUC of 0.921 with 95.7% sensitivity and 67.3% specificity. Thus, we suggest that the QPLEX^TM Alz plus assay is useful for prescreening brain Aβ levels in CN individuals, especially those aged >65 years, to prevent disease progression via the early detection of disease initiation.Subject terms: Alzheimer''s disease, Neural ageing, ELISA     

Label-free emission assay of mercuric ions using DNA duplexes of poly(dT)

In this study, an assay to quantify the presence of mercuric ions and methyl mercury by double-stranded DNA containing a poly(dT) sequence was developed using a light switch compound, Ru(phen)(2)(dppz)(2+) (1), which is known to intercalate into double-stranded DNA. Upon treatment with mercuric ions, the metal-to-ligand charge transfer (MLCT) emission derived from the intercalation of 1 was reduced due to the formation of DNA duplexes containing T-Hg(2+)-T base pairs by the dehybridization of poly(dT)-poly(dA) duplexes at room temperature. As the concentration of Hg(2+) was increased, the emission of 1 gradually decreased. This label-free method had a detection limit of 5 nM. Other metal ions, such as K(+), Ag(+), Ca(2+), Mg(2+), Zn(2+), Mn(2+), Co(2+), Ni(2+), Cu(2+), Cd(2+), Cr(3+), Fe(3+), had no significant effect on reducing emission. This emission method can differentiate matched and mismatched poly(dT) sequences based on the dehybridization rate of dsDNA and the rate decreased in the order of T(10)C·A(11)～ T(10)A·A(11) > T(10)G·A(11) > T(11)·A(11).     

Effects of post-annealing on electrical properties of amorphous Ga-doped Zn–Sn–O semiconductor films

We investigated the effect of post-annealing on the electrical properties of amorphous gallium-zinc-tin oxide (a-GZTO) films with different Ga contents. The films were deposited at room temperature by sputtering and annealed in air for 1 h. It was found that the doping with Ga, which acts as the carrier suppressor, contributes to the thermal stability of characteristic properties of a-GZTO thin films. The film with a small amount of Ga showed significant variations in carrier concentration according to the annealing temperature. Increases in carrier concentration and mobility can be ascribed to the reduction of subgap density of states by annealing. After annealing at 400 °C, however, the enrichment of Zn cations in surface region resulted in considerable changes in chemical bonding states and consequently, the carrier concentration decreased by two orders of magnitude for the low Ga-doped ZTO film.