Electronic properties of PbCl2 and PbBr2 using Compton scattering technique

We present the electron momentum densities of PbCl₂ and PbBr₂ using 661.65 keV γ-rays from 20 Ci ¹³⁷Cs source. To supplement our experimental investigations, we also report energy bands, density of states, Mulliken's population and Compton profiles of PbCl₂ and PbBr₂ using linear combination of atomic orbitals within Hartree–Fock and density functional theories. The energy bands are also computed employing full potential linearized augmented plane wave (FP-LAPW) method. Compton profiles are also analyzed in terms of equal-valence-electron-density scale. It shows that PbCl₂ is more covalent than PbBr₂, which is in agreement with the Mulliken's population analysis. It is seen that the Hartree–Fock and density functional theory based Compton line shapes show similar type of deviations from the experimental data. The luminescence properties of these halides are explained on the basis of energy band and density of states.     

Update of NIST half-life results corrected for ionization chamber source-holder instability

As reported at the ICRM 2011, it was discovered that the source holder used for calibrations in the NIST 4πγ ionization chamber (IC) was not stable. This has affected a large number of half-life measurement results previously reported and used in compilations of nuclear data. Corrections have been made on all of the half-life data based on the assumption that the changes to the ionization chamber response were gradual. The corrections are energy dependent and therefore radionuclide specific. This presentation will review our results and present the recommended changes in half-life values and/or uncertainties.     

LiSr4(BO3)3:Ce3+ phosphor as a new material for ESR dosimetry

LiSr₄(BO₃)₃:0.01Ce³⁺ phosphor was investigated to assess its potential as a material for measurements of radiotherapeutic doses with electron spin resonance (ESR). The ESR spectrum of the phosphor irradiated with ⁶⁰Co features five ESR signals. An isochronal annealing experiment has shown that the strongest of these signals is associated with the same trap center as the 473 K peak on the TL glow curve of this material. The dose–response is linear in the studied range from 0.89 to 90.30 Gy. Fading of the signal was also investigated.     

Spatially and temporally controlled immune cell interactions using microscale tools

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A combination of Sinomenine and Methotrexate reduces joint damage of collagen induced arthritis in rats by modulating osteoclast-related cytokines

ObjectiveTo analyze the combination therapy of Sinomenine (SIN) and Methotrexate (MTX) in rheumatoid arthritis (RA), we herein demonstrated the combination effect of SIN and MTX on collagen-induced arthritis (CIA) in rats through their modulation on osteoclast-related cytokines.MethodsCIA was induced by the immunization of type II collagen (CII) in SD rats. SIN and MTX were administrated alone or in combination after the onset of arthritis. Arthritis index and histological analysis were used to evaluate the effect of treatments. Effects of SIN and MTX on expression of receptor activator of NF-κB ligand (RANKL) and osteopontin (OPN) in synovial tissues were assayed by immunohistochemistry. RANKL, osteoprotegerin (OPG), IL-6, IL-17 and matrix metalloproteinases (MMPs) in rat serum were measured by ELISA. The expression of osteoclast-related cytokines in fibroblast-like synoviocytes (FLS) from RA patients was assayed by RT-PCR.ResultsSIN and MTX combination additively reduced the inflammatory symptoms and joint damage in CIA. Combination of SIN and MTX significantly repressed synovial RANKL and OPN production. SIN and MTX exhibited complementary and synergistic effect upon down-regulating RANKL, IL-6, IL-17 and MMPs in rat serum. SIN and MTX also modulated the expression of RANKL and OPG in RA-FLS.ConclusionSIN and MTX have additive effects, decreasing inflammation and joint damage in CIA rats by modulating osteoclast-related cytokines. These results are indicative of the combined effect of SIN and MTX for anti-arthritic treatment in RA.     

Development and characterization of rhVEGF-loaded poly(HEMA–MOEP) coatings electrosynthesized on titanium to enhance bone mineralization and angiogenesis

Osteointegration of titanium implants could be significantly improved by coatings capable of promoting both mineralization and angiogenesis. In the present study, a copolymeric hydrogel coating, poly-2-hydroxyethyl methacrylate-2-methacryloyloxyethyl phosphate (P(HEMA–MOEP)), devised to enhance calcification in body fluids and to entrap and release growth factors, was electrosynthesized for the first time on titanium substrates and compared to poly-2-hydroxyethyl methacrylate (PHEMA), used as a blank reference. Polymers exhibiting negatively charged groups, such as P(HEMA–MOEP), help to enhance implant calcification. The electrosynthesized coatings were characterized by X-ray photoelectron spectroscopy and atomic force microscopy. MG-63 human osteoblast-like cell behaviour on the coated specimens was investigated by scanning electron microscopy, MTT viability test and osteocalcin mRNA detection. The ability of negatively charged phosphate groups to promote hydroxyapatite-like calcium phosphate deposition on the implants was explored by immersing them in simulated body fluid. Similar biological responses were observed in both coated specimens, while calcium-phosphorus globules were detected only on P(HEMA–MOEP) surfaces pretreated with alkaline solution. Testing of the ability of P(HEMA–MOEP) hydrogels to entrap and release human recombinant vascular endothelial growth factor, to tackle the problem of insufficient oxygen and nutrient delivery, suggested that P(HEMA–MOEP)-coated titanium prostheses could represent a multifunctional material suitable for bone restoration applications.