Finite element analysis of the Poisson–Boltzmann equation coupled with chemical equilibriums: redistribution and transport of protons in nanophase separated polymeric acid–base proton exchange membranes

<p>The finite element analysis is applied to the study of the redistribution and transport of protons in model nanophase separated polymeric acid–base composite membranes by the Poisson–Boltzmann equation coupled with the acid and base dissociation equilibriums for the first time. Space charge redistribution in terms of proton and hydroxide redistributions is observed at the interfaces of acidic and basic domains. The space charge redistribution causes internal electrostatic potential, and thus, promotes the macroscopic transport of protons in the acid–base composite membranes.</p

Crystal-Site Engineering Control for the Reduction of Eu³⁺ to Eu²⁺ in CaYAlO₄: Structure Refinement and Tunable Emission Properties

In this article, Eu-activated CaYAlO₄ aluminate phosphors were synthesized by a solid-state reaction. Under UV light excitation, characteristic red line emission of Eu³⁺ was detected in the range of 570–650 nm. In addition, we introduced crystal-site engineering approach into the CaYAlO₄ host through incorporation of Si⁴⁺–Ca²⁺ to replace Al³⁺–Y³⁺, which would shrink the AlO₆ octahedrons, accompanied by the expansion of CaO₉ polyhedron, and then enable the partial reduction of Eu³⁺ to Eu²⁺. The crystal structure and underlying mechanism have been clarified on the basis of the Rietveld refinement analysis. The PL spectra of Ca_{0.99+<i>x</i>}Y_1–<i>x</i>Al_1–<i>x</i>Si_<i>x</i>O₄:Eu_0.01 (<i>x</i> = 0–0.30) exhibit both green emission of Eu²⁺ (4f⁶5d¹–4f⁷, broadband around 503 nm) and red-orange emission of Eu³⁺ (⁵D₀–⁷F_1,2, 593 and 624 nm) under UV light excitation with a quantum yield of 38.5%. The CIE coordinates of Ca_{0.99+<i>x</i>}Y_1–<i>x</i>Al_1–<i>x</i>Si_<i>x</i>O₄:Eu_0.01 (<i>x</i> = 0–0.30) phosphors are regularly shifted from (0.482, 0.341) to (0.223, 0.457) with increasing <i>x</i>, which would expand the application of Eu. Furthermore, this investigation reveals the correlations of structure and property of luminescent materials, which would shed light on the development of novel phosphors suitable for lighting and display applications

Data_Sheet_2_Identification and Characterization of a Cis Antisense RNA of the rpoH Gene of Salmonella enterica Serovar Typhi.DOCX

<p>Antisense RNAs from complementary strands of protein coding genes regulate the expression of genes involved in many cellular processes. Using deep sequencing analysis of the Salmonella enterica serovar Typhi (S. Typhi) transcriptome, a novel antisense RNA encoded on the strand complementary to the rpoH gene was revealed. In this study, the molecular features of this antisense RNA were assessed using northern blotting and rapid amplification of cDNA ends. The 3,508 nt sequence of RNA was identified as the antisense RNA of the rpoH gene and was named ArpH. ArpH was found to attenuate the invasion of HeLa cells by S. Typhi by regulating the expression of SPI-1 genes. In an rpoH mutant strain, the invasive capacity of S. Typhi was increased, whereas overexpression of ArpH positively regulates rpoH mRNA levels. Results of this study suggest that the cis-encoded antisense RNA ArpH is likely to affect the invasive capacity of S. Typhi by regulating the expression of rpoH.</p

Data_Sheet_1_Identification and Characterization of a Cis Antisense RNA of the rpoH Gene of Salmonella enterica Serovar Typhi.DOC

<p>Antisense RNAs from complementary strands of protein coding genes regulate the expression of genes involved in many cellular processes. Using deep sequencing analysis of the Salmonella enterica serovar Typhi (S. Typhi) transcriptome, a novel antisense RNA encoded on the strand complementary to the rpoH gene was revealed. In this study, the molecular features of this antisense RNA were assessed using northern blotting and rapid amplification of cDNA ends. The 3,508 nt sequence of RNA was identified as the antisense RNA of the rpoH gene and was named ArpH. ArpH was found to attenuate the invasion of HeLa cells by S. Typhi by regulating the expression of SPI-1 genes. In an rpoH mutant strain, the invasive capacity of S. Typhi was increased, whereas overexpression of ArpH positively regulates rpoH mRNA levels. Results of this study suggest that the cis-encoded antisense RNA ArpH is likely to affect the invasive capacity of S. Typhi by regulating the expression of rpoH.</p

Cytotoxic pyrone derivatives from the deep-sea-derived fungus <i>Cladosporium halotolerans</i> FS702

Two new compounds (R)-6-((8S)-hydroxypropyl)-2-methyl-5,6-dihydro-4H-pyran-4-one (1) and (R)-6-((8R)-hydroxypropyl)-2-methyl-5,6-dihydro-4H-pyran-4-one (2), together with four known compounds were isolated from the marine-derived fungus Cladosporium halotolerans FS702. The structures of these compounds were determined on the basis of extensive spectroscopic analysis including 1D/2D NMR, IR, UV, HRESIMS, ECD calculations as well as the modified Mosher’s method. Cytotoxic assay results showed that compound 2 had significant cytotoxic activity against SF-268, MCF-7, HepG-2, and A549 cells lines with IC50 values of 0.16, 0.47, 0.33 and 0.23 µM, respectively.</p

Multifunctional Hydroxyapatite/Na(Y/Gd)F₄:Yb³⁺,Er³⁺ Composite Fibers for Drug Delivery and Dual Modal Imaging

Porous hydroxyapatite (HAp) composite fibers functionalized with up-conversion (UC) luminescent and magnetic Na­(Y/Gd)­F₄:Yb³⁺,Er³⁺ nanocrystals (NCs) have been fabricated via electrospinning. After transferring hydrophobic oleic acid-capped Na­(Y/Gd)­F₄:Yb³⁺,Er³⁺ NCs into aqueous solution, these water-dispersible NCs were dispersed into precursor electrospun solution containing CTAB. Na­(Y/Gd)­F₄:Yb³⁺,Er³⁺@HAp composite fibers were fabricated by the high temperature treatment of the electrospun Na­(Y/Gd)­F₄:Yb³⁺,Er³⁺ NCs decorated precursor fibers. The biocompatibility test on MC 3T3-E1 cells using MTT assay shows that the HAp composite fibers have negligible cytotoxity, which reveals the HAp composite fibers could be a drug carrier for drug delivery. Because the contrast brightening is enhanced at increased concentrations of Gd³⁺, the HAp composite fibers can serve as T₁ magnetic resonance imaging contrast agents. In addition, the composites uptaken by MC 3T3-E1 cells present the UC luminescent emission of Er³⁺ under the excitation of a 980 nm near-infrared laser. The above findings reveal Na­(Y/Gd)­F₄:Yb³⁺,Er³⁺@HAp composite fibers have potential applications in drug storage/release and magnetic resonance/UC luminescence imaging

Wide-Band Excited YTiTaO₆: Eu³⁺/Er³⁺ Phosphors: Structure Refinement, Luminescence Properties, and Energy Transfer Mechanisms

Eu³⁺-/Er³⁺-activated YTiTaO₆ phosphors have been prepared via conventional solid state reaction process. X-ray diffraction (XRD) and structure refinement, Raman spectra, X-ray photoelectron Spectrum (XPS), photoluminescence (PL) spectra, cathodoluminescence (CL) spectra, and lifetimes were utilized to characterize the synthesized samples. Under UV light excitation, the YTiTaO₆ sample shows broad band emission centered near 505 nm due to the Ta­(Ti)­O₆ polyhedron. Eu³⁺ and Er³⁺ ions doped YTiTaO₆ samples show strong line emissions coming from the characteristic f–f transitions. The energy transfer from the Ta­(Ti)­O₆ group of the host to Eu³⁺ and Er³⁺ in YTiTaO₆ phosphors has been demonstrated to be a resonant type via a dipole–dipole mechanism, and the critical distance (<i>R</i>_C) for host emission to Eu³⁺ and Er³⁺ calculated by concentration quenching method are 10.02 and 18.86 Å, respectively. Under the low voltage electron beam excitation, the CL spectra of YTiTaO₆, YTiTaO₆: Eu³⁺, and YTiTaO₆: Er³⁺ samples are similar to their PL spectra, exhibiting bluish-green, red, and green luminescence, respectively, which indicates that these materials might be promising for application in solid-state lighting and field-emission displays

Dynamic Fluctuation of U³⁺ Coordination Structure in the Molten LiCl–KCl Eutectic via First Principles Molecular Dynamics Simulations

The dynamic fluctuation of the U³⁺ coordination structure in a molten LiCl–KCl mixture was studied using first principles molecular dynamics (FPMD) simulations. The radial distribution function, probability distribution of coordination numbers, fluctuation of coordination number and cage volume, self-diffusion coefficient and solvodynamic mean radius of U³⁺, dynamics of the nearest U–Cl distances, and van Hove function were evaluated. It was revealed that fast exchange of Cl^– occurred between the first and second coordination shells of U³⁺ accompanied with fast fluctuation of coordination number and rearrangement of coordination structure. It was concluded that 6-fold coordination structure dominated the coordination structure of U³⁺ in the molten LiCl–KCl–UCl₃ mixture and a high temperature was conducive to the formation of low coordinated structure

UV-Emitting Upconversion-Based TiO₂ Photosensitizing Nanoplatform: Near-Infrared Light Mediated <i>in Vivo</i> Photodynamic Therapy <i>via</i> Mitochondria-Involved Apoptosis Pathway

Photodynamic therapy (PDT) is a promising antitumor treatment that is based on the photosensitizers that inhibit cancer cells by yielding reactive oxygen species (ROS) after irradiation of light with specific wavelengths. As a potential photosensitizer, titanium dioxide (TiO₂) exhibits minimal dark cytotoxicity and excellent ultraviolet (UV) light triggered cytotoxicity, but is challenged by the limited tissue penetration of UV light. Herein, a novel near-infrared (NIR) light activated photosensitizer for PDT based on TiO₂-coated upconversion nanoparticle (UCNP) core/shell nanocomposites (UCNPs@TiO₂ NCs) is designed. NaYF₄:Yb³⁺,Tm³⁺@NaGdF₄:Yb³⁺ core/shell UCNPs can efficiently convert NIR light to UV emission that matches well with the absorption of TiO₂ shells. The UCNPs@TiO₂ NCs endocytosed by cancer cells are able to generate intracellular ROS under NIR irradiation, decreasing the mitochondrial membrane potential to release cytochrome <i>c</i> into the cytosol and then activating caspase 3 to induce cancer cell apoptosis. NIR light triggered PDT of tumor-bearing mice with UCNPs@TiO₂ as photosensitizers can suppress tumor growth efficiently due to the better tissue penetration than UV irradiation. On the basis of the evidence of <i>in vitro</i> and <i>in vivo</i> results, UCNPs@TiO₂ NCs could serve as an effective photosensitizer for NIR light mediated PDT in antitumor therapy

Rapid, Large-Scale, Morphology-Controllable Synthesis of YOF:Ln³⁺ (Ln = Tb, Eu, Tm, Dy, Ho, Sm) Nano-/Microstructures with Multicolor-Tunable Emission Properties

YOF:Ln³⁺ (Ln = Tb, Eu, Tm, Dy, Ho, Sm) nano-/microstructures with a variety of novel and well-defined morphologies, including nanospheres, nanorod bundles, and microspindles, have been prepared through a convenient modified urea-based homogeneous precipitation (UBHP) technique followed by a heat treatment. The sizes and morphologies of the YOF products could be easily modulated by changing the pH values and fluoride sources. XRD, TG-DTA, FT-IR, SEM, and TEM, as well as photoluminescence (PL) and cathodoluminescence (CL) spectra, were used to characterize the prepared samples. The YOF:Ln³⁺ nanospheres show the characteristic f–f transitions of Ln³⁺ (Ln = Tb, Eu, Tm, Dy, Ho, Sm) ions and give bright green, red, blue, yellow, blue-green, and yellow-orange emission, respectively, under UV light and low-voltage electron beam excitation. Furthermore, YOF:0.03Tb³⁺ phosphors exhibit green luminescence with superior properties in comparison with the commercial phosphor ZnO:Zn to a degree, which is advantageous for improving display quality. Because of the simultaneous luminescence of Ln³⁺ in the YOF host, the luminescence colors of YOF:Ln³⁺ phosphors can be precisely adjusted by changing the doped Ln³⁺ ions and corresponding concentrations, which makes these materials hold great promise for applications in field-emission displays