Radiolabeling,Preparation, and Bioevaluation of 99mTc-Azathioprine as a Potential Targeting Agent for Solid Tumor Imaging

Radiochemistry - Azathioprine, an antitumor agent, was labeled with 99mTc using stannous chloride dihydrate as a reducing agent. Factors such as the amounts of the reducing agent and substrate, pH,...     

Defects in Carbon-Rich Ferrite of Cold-Drawn Pearlitic Steel Wires

By means of X-ray line profile analysis and positron lifetime spectroscopy, densities of deformation-induced defects in carbon-rich ferrite of a series of cold-drawn pearlitic steel wires with true strains (ε) up to 5 are characterized. It is shown that both the dislocation densities and the vacancy cluster concentrations increase continuously with increasing ε. On the basis of the measured defect densities, values of defect hardening are estimated. The result shows that contributions of the defect hardening to the total tensile strength of the wires reach nearly 40 pct, which is mainly ascribed to the dislocation hardening. Chemical surroundings of the defects in the carbon-rich ferrite are investigated by coincidence Doppler broadening spectroscopy. The association of carbon with the defects in ferrite is demonstrated.     

Viable Mycobacterium avium ssp. paratuberculosis isolated from calf milk replacer

When advising farmers on how to control Johne's disease in an infected herd, one of the main recommendations is to avoid feeding waste milk to calves and instead feed calf milk replacer (CMR). This advice is based on the assumption that CMR is free of viable Mycobacterium avium ssp. paratuberculosis (MAP) cells, an assumption that has not previously been challenged. We tested commercial CMR products (n = 83) obtained from dairy farms around the United States by the peptide-mediated magnetic separation (PMS)-phage assay, PMS followed by liquid culture (PMS-culture), and direct IS900 quantitative PCR (qPCR). Conventional microbiological analyses for total mesophilic bacterial counts, coliforms, Salmonella, coagulase-negative staphylococci, streptococci, nonhemolytic Corynebacterium spp., and Bacillus spp. were also performed to assess the overall microbiological quality of the CMR. Twenty-six (31.3%) of the 83 CMR samples showed evidence of the presence of MAP. Seventeen (20.5%) tested positive for viable MAP by the PMS-phage assay, with plaque counts ranging from 6 to 1,212 pfu/50 mL of reconstituted CMR (average 248.5 pfu/50 mL). Twelve (14.5%) CMR samples tested positive for viable MAP by PMS-culture; isolates from all 12 of these samples were subsequently confirmed by whole-genome sequencing to be different cattle strains of MAP. Seven (8.4%) CMR samples tested positive for MAP DNA by IS900 qPCR. Four CMR samples tested positive by both PMS-based tests and 5 CMR samples tested positive by IS900 qPCR plus one or other of the PMS-based tests, but only one CMR sample tested positive by all 3 MAP detection tests applied. All conventional microbiology results were within current standards for whole milk powders. A significant association existed between higher total bacterial counts and presence of viable MAP indicated by either of the PMS-based assays. This represents the first published report of the isolation of viable MAP from CMR. Our findings raise concerns about the potential ability of MAP to survive manufacture of dried milk-based products.     

Flotation of α-iron(III) oxide by cetyltrimethylammonium bromide and its activation by phosphates

The zero point of charge, z.p.c., of chemically prepared α-Fe₂O₃ was found at pH 6.9. The adsorption isotherms of cetyltrimethylammonium bromide, CTAB, had a Langmuir shape and shifted to higher adsorption density as the pH increased above the z.p.c. The variation of the adsorption plateau with pH could be correlated with the change in ζ potential accompanying the adsorption of CTAB. The graphs of the recovery of α-Fe₂O₃ floated by CTAB plotted against its equilibrium concentration exhibited maxima, which became higher as the pH increased from 6 to 10. The adsorption capacity of α-Fe₂O₃ for phosphate ions markedly decreased and their desorption increased as the pH increased. The drop in ζ potential of α-Fe₂O₃ in phosphate solution became smaller as the pH increased. In presence of phosphate ions, the adsorption capacity of α-Fe₂O₃ for CTAB markedly increased at pH 6, the enhancement becoming less marked as the pH increased. The enhancement paralleled the phosphate adsorption. In presence of phosphate ions, the recovery of α-Fe₂O₃ floated by CTAB was higher, the activation decreasing as the pH increased. The maximum recovery was shifted to lower CTAB concentration compared to the recovery of unactivated α-Fe₂O₃.     

Influence of hydrogen on the deformation morphology of vanadium (1 0 0) micropillars in the α-phase of the vanadium–hydrogen system

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Solubility of Gases in Vitreous Silica Described by a Distribution of Dissolution Energies

The solubility of gases in vitreous silica complies well with Henry's Law at low pressures. Deviations observed at high pressures have been explained by site saturation, i.e., the number of dissolved molecules approaches the number of available sites that are assumed to have all the same energy of solution. In the present study, the observed deviations from Henry's Law are explained by a gradual saturation of sites of increasing energy. Experimental data of the solubility of hydrogen, helium, and neon in vitreous silica can be described by a Gaussian distribution of dissolution energies and Fermi-Dirac statistics. The solubility of hydrogen in metallic glasses, as well as the solubility of small molecules in glassy polymers, has been interpreted, and now, glasses in vitreous silica fit into this general concept of small particles in amorphous matrices.