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The nuclear effectors of the EGFR and Notch signaling pathways with transcription factor Lozenge, directly regulate D-Pax2 transcription in cone cells of the Drosophila eye disc. Specificity of D-Pax2 expression can be changed upon genetic manipulation of the inputs. Relatively small numbers of temporally/spatially controlled signals received by a set of pluripotent cells can set up the unique combinations of activated transcription factors needed to regulate target genes and specify distinct cell fates in the group, finally. Likely similar mechanisms specify pattern formation in vertebrate developmental systems that involve cell-cell communication.

• RbCaF3:Dy3+ Phosphors were synthesized through solid state reaction technique. • Dual-luminescence properties of the RbCaF 3 :Dy3+ phosphors were investigated. • The sharp and strong emission was obtained at 484 nm for RbCaF 3 :Dy3+ phosphor. • The concentration quenching occurs at 0.06 mol% and calculated R c value is 3.91 Å. A series of Dy3+ activated RbCaF 3 phosphors was synthesized by the conventional high temperature solid state reaction technique under ambient atmosphere. The structural properties and morphology of synthesized compounds were analyzed by PXRD and FE-SEM, respectively. The chemical composition of synthesized phosphors was obtained by EDAX. The phosphor was excited at 386 nm and monitored at 484 and 574 nm, and the strongest peak was located at 484 nm (blue region). In addition, the point of RbCaF 3 :Dy3+ with calculated chromaticity coordinates in the CIE diagram was located in the yellow region. TL characteristics of the RbCaF 3 :Dy3+ phosphor was analyzed and the glow curve peak was emitted at 355 K. The symmetry factor, Balarin parameter, activation energy and frequency factor were calculated by Chen method from the TL glow curve, and the TL signal degradation was also analyzed. [ABSTRACT FROM AUTHOR]

The outer membrane vesicles (OMVs) from bacteria are known to posses both defensive and protective functions and thus participate in community related functions. In the present study, outer membrane vesicles have been shown to protect the producer bacterium and two other bacterial species from the growth inhibitory effects of some antibiotics. The OMVs isolated from E. coli MG1655 protected the bacteria against membrane-active antibiotics colistin, melittin. The OMVs of E. coli MG1655 could also protect P. aeruginosa NCTC6751 and A. radiodioresistens MMC5 against these membrane-active antibiotics. However, OMVs could not protect any of these bacteria against the other antibiotics ciprofloxacin, streptomycin and trimethoprim. Hence, OMVs appears to protect the bacterial community against membrane-active antibiotics and not other antibiotics, which have different mechanism of actions. The OMVs of E. coli MG1655 sequester the antibiotic colistin, whereas their protein components degrade the antimicrobial peptide melittin. Proteomic analysis of OMVs revealed the presence of proteases and peptidases which appear to be involved in this process. Thus, the protection of bacteria by OMVs against antibiotics is situation dependent and the mechanism differs for different situations. These studies suggest that OMVs of bacteria form a common defense for the bacterial community against specific antibiotics. [ABSTRACT FROM AUTHOR]

Abstract: Human-β-defensins HBD-1–3 are important components of the innate immune system. Synthetic peptides Phd-1–3 with a single disulphide bond, spanning the cationic C-terminal region of HBD-1–3, have antimicrobial activity. The interaction of Phd-1–3 with model membranes was investigated using isothermal titration calorimetry (ITC) and steady-state fluorescence polarization to understand the biophysical basis for the mechanism of antimicrobial action. Calorimetric titration of POPE:POPG (7:3) vesicles with peptides at 25°C and 37°C showed complex profiles with two distinct regions of heat changes. The data indicate binding of Phd-1–3 at 37°C to both negative and zwitterionic lipid vesicles is exothermic with low enthalpy values (ΔH~ −1.3 to −2.8kcal/mol) as compared to amphipathic helical antibacterial peptides. The adsorption of peptides to negatively charged lipid membranes is modulated by electrostatic interactions that are described by surface partition equilibrium model using Gouy–Chapman theory. However, this model could not explain the isotherms of peptide binding to zwitterionic lipid vesicles. Fluorescence polarization of TMA-DPH (1-[4-(trimethylammonio) phenyl]-6-phenyl-1,3,5-hexatriene) and DPH (1,6-diphenyl-1,3,5-hexatriene) located in the head group and acyl chain region respectively, indicates that the peptides interact with interfacial region of negatively charged membranes. Based on the results obtained, we conclude that adsorption of cationic peptides Phd-1–3 on lipid surface do not result in conformational change or pore formation. It is proposed that interaction of Phd-1–3 with the negatively charged lipid head group causes membrane destabilization, which in turn affects the efficient functioning of cytoplasmic membrane proteins in bacteria, resulting in cell death. [Copyright &y& Elsevier]

The high-ordered crystal structure of a thermoelectric material does not delimit the phonon conductivity but shows improved electrical properties. Disordered crystal structures act as scattering centers for phonon, but at the expense of the electrical properties of the material. Hence, a diminished thermal (phonon) conductivity and improved electronic conductivity can be obtained from an incommensurate (IC) phase structure. This paper reports that TlBiSe 2 polycrystal material exhibits incommensurate (IC) phase (disordered structure). The 'Tl+' connecting chains and the disordered structure inherent in the IC phase enhance the TE properties in TlBiSe 2. The crystalline phase was confirmed for TlBiSe 2 by X-ray diffraction (XRD). These polycrystals have shown their characteristic Raman modes and micro flake-like morphology, as observed by Raman spectroscopy and field emission scanning electron microscopy (FESEM). X-ray photoelectron spectroscopy confirmed the IC phase formation by observing the characteristic binding energy shift of 'Tl' and 'Se' states. The parallel plane symmetry break in the IC phase has resulted in a hall carrier concentration (n) of 3.49 × 1020 cm−3 and mobility (μ) of 8.27 m2V−1s−1. Further, Seebeck coefficient showed 80 μV/K; the Wiedemann Franz law calculation reserved a lower electronic thermal conductivity of 0.003381 Wm−1K−1 and a power factor of 2.956 μW/m K2 has been attained. [ABSTRACT FROM AUTHOR]

In the present work, we report on luminescence properties of Eu3+ ions doped KBaScSi 3 O 9 silicate phosphors (KBSS) synthesized by high temperature solid state reaction method and the prepared phosphor samples were characterized through XRD, FE-SEM, photoluminescence and decay spectral measurements. The XRD pattern confirmed that the KBSS host lattice exhibited a monoclinic crystal structure. Room temperature photoluminescence (PL) spectroscopic results reveal that, on Eu3+ ion doping in the KBSS host matrix, the magnetic dipole transition (5D 0 → 7F 1) at 593 nm responsible for orange light, dominates the red emission with respect to the electric dipole transition (5D 0 → 7F 2) at 611 nm. The Judd-Ofelt (JO) intensity parameters Ω λ (λ = 2 and 4) have been calculated from the emission spectra to understand the nature of ligand environment around the Eu3+ ions. The radiative parameters, such as transition probability (A), stimulated emission cross-section ( σ P E ), radiative lifetime (τ R) and branching ratios (β R) corresponding to the 5D 0 →7F 0 , 5D 0 →7F 1 , 5D 0 →7F 2 , 5D 0 →7F 3 and 5D 0 →7F 4 emission transitions have been determined by using JO parameters and the refractive indices respectively. The concentration quenching effect for Eu3+ was found at the optimum doping concentration of 7 mol %. The CIE chromaticity coordinates were calculated from the luminescence spectra to explore the dominant emission colour of the title phosphors. The experimental lifetime values of 5D 0 level of the Eu3+ doped silicate phosphors have been calculated and the obtained results were discussed in detail. Image 1 • Higher Ω 2 values indicate the higher asymmetry around the Eu3+ ion site. • CIE 1931 diagram confirms that studied phosphors give red emission when excited at 466 nm. • KBSS:xEu phosphors excited at 466 nm shows a very high color purity in the range of 97.4%–98.8%. • 5D 0.→7F 2 of KBSS:0.07Eu phosphor exhibits higher A σ P E , β R values suitable for lasers. [ABSTRACT FROM AUTHOR]

Abstract: The La3+ substituted nanocrystalline strontium ferrite has been prepared by citrate combustion method using metal nitrate salts as cation precursors and citric acid as a fuel. The structural characteristics of the compounds have been evaluated using XRD and FTIR. The existence of the single-phase perovskite structure with nanocrystalline size has been confirmed from the X-ray powder diffraction patterns. The stretching and bending vibrations of the metal cations are confirmed from the FTIR spectra. The electrical conductivity of the materials is found to increase with increasing temperature measured by using a modified four-probe technique. The electrochemical behavior has been studied by using potentiostatic polarization method in KOH solutions at two different concentrations of 1 and 2M. From the polarization studies it has been found that the material La0.4Sr0.6FeO3 gives the lowest corrosion rate of 0.001mmpy in 1M KOH solution. [Copyright &y& Elsevier]

Structure and biological activities of synthetic peptides corresponding to bovine neutrophil β-defensin BNBD-12, GPLSC1GRNGGVC2IPIRC3 PVPMRQIGTC4 FGRPVKC5 C6RSW with disulfide connectivities C1-C5, C2-C4 and C3-C6 and its variants with one, two and three disulfide bridges have been investigated. Selective protection of cysteine thiols was necessary in the four and six cysteine containing peptides for the formation of disulfide connectivities as observed in BNBD-12. Circular dichroism (CD) spectra indicate that in aqueous medium, only a small fraction of molecules populate turn-like conformations. In the presence of micelles and lipid vesicles, the single, two and three disulfide containing peptides adopt β-hairpin or β-sheet structures. Antibacterial activity was observed for all the peptides, irrespective of the number of disulfide bridges or how they were connected. Our results suggest that a rigid β-sheet structure or the presence of three disulfide bridges does not appear to be stringent requirements for antibacterial activity in β-defensins. [Copyright &y& Elsevier]

A new class of cyclobisamides, having the general profile of amino acid (cystine or serine)–ether composites, as potentially efficient ion transporters has been designed and synthesized. In model membranes, the adamantane harboring composites exhibited 57–66% of gramicidin A activity in ion transport. [Copyright &y& Elsevier]