Evaluation of Spatial Resolution of Virtual Monochromatic Imaging In Vitro: Effect of Energy Level and Contrast.

OBJECTIVE: Our aim was to evaluate effects of the energy level and contrast on the spatial resolution of virtual monochromatic imaging (VMI). METHODS: With 2 types of computed tomographic (CT) scanners (Discovery CT750 HD and Revolution CT), we scanned an elliptical cylinder acrylic phantom with 20- or 40-fold dilutions of contrast medium and obtained VMI data sets at 40, 50, 60, and 70 keV. We evaluated the effects of energy levels and contrast on modulation transfer function (MTF) and the effect of energy levels on noise power spectra (NPS). RESULTS: With both CT scanners, MTF decreased significantly as the energy level decreased. The effect of the dilution of contrast media on MTF varied with CT scanners. With both scanners, NPS curves demonstrate uniform increase in NPS across the entire spatial frequency as the energy levels decreased. CONCLUSIONS: The energy level and contrast can affect the spatial resolution of VMIs.

Preparation of C2-symmetric allenes by palladium-catalyzed double-nucleophilic substitution on 3-bromopenta-2,4-dienyl acetate.

Easily accessible 3-bromopenta-2,4-dienyl acetate was applied to the palladium-catalyzed reaction with soft nucleophiles. The reaction proceeded through the stepwise 2-fold nucleophilic substitution via formal S(N)2' and S(N)2 processes giving the various doubly functionalized C(2)-symmetric allenes in good yields.

Synthetic osteopontin-derived peptide SVVYGLR can induce neovascularization in artificial bone marrow scaffold biomaterials.

We have previously reported that an osteopontin-derived SVVYGLR peptide exhibited potent angiogenic activity in vitro and in vivo. In the present study, the focus points were on the in vitro effect of SVVYGLR on bone marrow stromal cell proliferation, as well as its in vivo effect on bone tissue formation when grafts made of CO3Ap-collagen sponge- as a scaffold biomaterial containing the SVVYGLR motif - were implanted. SVVYGLR peptide promoted bone marrow stromal cell proliferation. When a CO3Ap-collagen sponge containing SVVYGLR peptide was implanted as a graft into a tissue defect created in rat tibia, the migration of numerous vascular endothelial cells - as well as prominent angiogenesis - inside the graft could be detected after one week. These results thus suggested that our scaffold biomaterials including the peptide could be useful for bone tissue regeneration.