Thermally stimulated luminescence studies of undoped and doped CaB₄O₇ compounds

Thermoluminescence of undoped and doped CaB₄O₇ with activators such as Cu and Mn has been investigated. The polycrystalline samples of undoped and doped CaB₄O₇ are prepared by melting method. The formation of CaB₄O₇ compound is checked by X-ray diffraction study and the compound is found to have orthorhombic structure at room temperature. The TSL studies of undoped CaB₄O₇ sample shows two glow peaks at 150°C and 265°C and one shoulder at around 190°C. The TSL studies of Cu doped CaB₄O₇ sample also shows two glow peaks at 160°C and 270°C and a shoulder at around 230°C whereas the TSL glow curves of Mn doped CaB₄O₇ has only one single strong glow peak at 135°C. A comparative TSL studies of these compounds shows that CaB₄O₇ compound doped with Mn is the most sensitive and the TSL intensity is enhanced by about 40 times when compared with the TSL intensity of undoped CaB₄O₇ compound. The trap parameters namely order of kinetics (b), activation energy (E) and frequency factor (s) associated with the 135°C glow peak of CaB₄O₇: Mn phosphor are determined using isothermal decay and glow curve shape (Chen's) methods

Investigation of Thermal Stability of Red Emitting SrGd2(1 – x)Eu2xO4 Phosphors for Lighting and Display Applications

Novel red-emitting SrGd2(1 – x)Eu2xO4 samples were prepared via combustion method. Structural and optical characteristics were examined with the help of XRD, FTIR, FESEM and photoluminescence (PL) studies. FESEM images reveal agglomerated rod-like morphology. The intense red emission corresponding to 5D0→7F2 transitions under UV-excitation 276 nm and higher thermal stability up to 250 °C of SrGd2(1 – x)Eu2xO4 reveals its applicability in lighting and display devices

Comments on a class of orthogonality relations relevant to fluid-structure interaction

Copyright @ 2011 Springer Science+Business Media B.V

In Vivo Electroporation Enhances the Immunogenicity of an HIV-1 DNA Vaccine Candidate in Healthy Volunteers

DNA-based vaccines have been safe but weakly immunogenic in humans to date.We sought to determine the safety, tolerability, and immunogenicity of ADVAX, a multigenic HIV-1 DNA vaccine candidate, injected intramuscularly by in vivo electroporation (EP) in a Phase-1, double-blind, randomized placebo-controlled trial in healthy volunteers. Eight volunteers each received 0.2 mg, 1 mg, or 4 mg ADVAX or saline placebo via EP, or 4 mg ADVAX via standard intramuscular injection at weeks 0 and 8. A third vaccination was administered to eleven volunteers at week 36. EP was safe, well-tolerated and considered acceptable for a prophylactic vaccine. EP delivery of ADVAX increased the magnitude of HIV-1-specific cell mediated immunity by up to 70-fold over IM injection, as measured by gamma interferon ELISpot. The number of antigens to which the response was detected improved with EP and increasing dosage. Intracellular cytokine staining analysis of ELISpot responders revealed both CD4+ and CD8+ T cell responses, with co-secretion of multiple cytokines.This is the first demonstration in healthy volunteers that EP is safe, tolerable, and effective in improving the magnitude, breadth and durability of cellular immune responses to a DNA vaccine candidate.ClinicalTrials.gov NCT00545987

Evasion of IFN-γ Signaling by Francisella novicida Is Dependent upon Francisella Outer Membrane Protein C

Francisella tularensis is a Gram-negative facultative intracellular bacterium and the causative agent of the lethal disease tularemia. An outer membrane protein (FTT0918) of F. tularensis subsp. tularensis has been identified as a virulence factor. We generated a F. novicida (F. tularensis subsp. novicida) FTN_0444 (homolog of FTT0918) fopC mutant to study the virulence-associated mechanism(s) of FTT0918.The ΔfopC strain phenotype was characterized using immunological and biochemical assays. Attenuated virulence via the pulmonary route in wildtype C57BL/6 and BALB/c mice, as well as in knockout (KO) mice, including MHC I, MHC II, and µmT (B cell deficient), but not in IFN-γ or IFN-γR KO mice was observed. Primary bone marrow derived macrophages (BMDM) prepared from C57BL/6 mice treated with rIFN-γ exhibited greater inhibition of intracellular ΔfopC than wildtype U112 strain replication; whereas, IFN-γR KO macrophages showed no IFN-γ-dependent inhibition of ΔfopC replication. Moreover, phosphorylation of STAT1 was downregulated by the wildtype strain, but not the fopC mutant, in rIFN-γ treated macrophages. Addition of NG-monomethyl-L-arginine, an NOS inhibitor, led to an increase of ΔfopC replication to that seen in the BMDM unstimulated with rIFN-γ. Enzymatic screening of ΔfopC revealed aberrant acid phosphatase activity and localization. Furthermore, a greater abundance of different proteins in the culture supernatants of ΔfopC than that in the wildtype U112 strain was observed.F. novicida FopC protein facilitates evasion of IFN-γ-mediated immune defense(s) by down-regulation of STAT1 phosphorylation and nitric oxide production, thereby promoting virulence. Additionally, the FopC protein also may play a role in maintaining outer membrane stability (integrity) facilitating the activity and localization of acid phosphatases and other F. novicida cell components

Thermally stimulated luminescence studies of undoped, Cu and Mn doped BaSO₄compounds

435-438Thermally stimulated luminescence (TSL) of undoped and doped BaSO4 with activators such as Cu and Mn has been investigated. The polycrystalline samples of undoped and doped BaSO4 are prepared by melting method. The formation of BaSO4 compound is confirmed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) studies. Comparison of TL intensity of the most intensive glow peak of Cu doped BaSO4 compound with that of undoped BaSO4 shows that addition of Cu impurity in BaSO4 compound enhances the TL intensity by about 9 times. However, the addition of Mn impurity to undoped BaSO4 increases the TL intensity by about three times when compared with that of undoped BaSO4. Among the studied samples namely undoped, Cu and Mn doped BaSO4; Cu-doped BaSO4 has been found to be the most sensitive