• Sweeney Gustafson posted an update 4 hours, 21 minutes ago

    The purpose of this work was to assess technical performance of a prototype high-ratio (r29), 80 line cm-1grid for imaging conditions which mimic those for adult cardiovascular angiography. The standard equipment r15, 80 line cm-1grid was used as a reference. Plastic Water®LR phantoms with thickness in the range 20-44 cm were used to simulate adult patient attenuation and scatter. Grids were tested using x-ray field of view 20 and 25 cm and x-ray source to detector distance (SID) 107 and 120 cm. The primary transmission fraction (TP) was measured using both narrow beam geometry and a lead beam stop (BS) technique. Scatter transmission (TS) was measured with the lead BS technique. The quantum signal to noise ratio improvement factor (KSNR) was used to describe relative grid performance. The experimental conditions required revised theory to assess grid performance. Theory to account for the detector glare and underestimation of scatter intensity by the lead BS method was developed. Also, novelKSNRtheory was developed to allow direct comparison of two grids operated at different SID. MeanTPwas modestly lower for the r29 versus r15 grid (0.69 versus 0.75). When tested under equivalent scatter condition, TSof the r29 grid was approximately ½ that of the r15 grid (0.18 versus 0.34).KSNRof the r29 grid at SID 120 cm compared to the r15 grid at SID 107 cm increased linearly with phantom thickness (range 1.0 to ∼1.16). Findings of this work indicate that the r29 grid used at SID 120 cm is expected to provide improved image quality (or reduced patient radiation dose) when compared to the r15 grid used at SID 107 cm for adult cardiovascular patients and that the potential benefit of the r29 grid increases with patient thickness >20 cm.There is a clear relationship between the self-assembling architecture of nanoparticles (NPs) and their physical properties, and they are currently used in a variety of applications, including optical sensors. Polymer-tethered NPs, which are created by grafting polymers onto NPs to control the self-assembly of NPs, have attracted considerable attention. Recent synthetic techniques have made it possible to synthesize a wide variety of polymers and thereby create NPs with many types of surfaces. However, self-assembled structures have not been systematically classified because of the large number of tuning parameters such as the polymer length and graft density. In this study, by using coarse-grained molecular simulation, we investigated the changes in the self-assembled structure of polymer-tethered NP solutions confined in nanotubes due to the chemical properties of polymers. Three types of tethered polymer NP models were examined homo hydrophilic, diblock hydrophilic-hydrophobic (HI-HO), and diblock hydrophobic-hydrophilic. Under strong confinement, the NPs were dispersed in single file at low axial pressure. As the pressure increased, multilayered lamellar was observed in the HI-HO model. In contrast, under weak confinement, the difference in the pressure at which the phases emerge, depending on the model, was significant. By changing the chemical properties of the grafted polymer, the thermodynamic conditions (the axial pressure in this study) under which the phases appear is altered, although the coordination of NPs remains almost unchanged. BMS-986235 ic50 Our simulation offers a theoretical guide for controlling the morphologies of self-assembled polymer-tethered NPs, a novel system that may find applications in nanooptical devices or for nanopatterning.Xenogeneic bone has good biological activity, but eliminating immunogenicity, while retaining osteogenic abilities, is a challenge. By combining xenogeneic bone with poly amino acid (PAA) that has an amide bond structure, a new type of composite conforming to bionics and low immunogenicity may be obtained. In this study, according to the principles of component bionics, three composites of delipidized cancellous bone powder (DCBP) and PAA were designed and obtained by anin situpolycondensation method, an extrusion molding (EM) method, and a solution-blend method. The three composites were all macroscopically uniform, non-cytotoxic, and demonstrated low immunogenicity by effective removal of residual antigens during preparation. Compared with PAA, mouse bone marrow mesenchymal stem cells (BMSCs) on the surfaces of three composites showed different cellular morphologies. The effects of different preparation methods and cellular morphology on cellular differentiation were confirmed by alkaline phosphatase activity, calcium nodule formation and the expression levels of osteogenic differentiation-related genes (bone morphogenetic protein 2, runt-related transcription factor 2, osteopontin and osteocalcin). Among these composites, DCBP/PAA EM showed best cell proliferation and osteogenic differentiationin vitro, and possessed greater bone formation than PAA in a rabbit femoral condyle study. This study may provide a new method for preparing bioactive bone repair materials with low immunogenicity and superior ability to stimulate differentiation of BMSCsin vitroand osteogenesisin vivo. DCBP/PAA EM might be a promising bone repair material for bone defect treatment.Due to its low immunogenic potential and the possibility to fine-tune their properties, materials made of recombinant engineered spider silks are promising candidates for tissue engineering applications. However, vascularization of silk-based scaffolds is one critical step for the generation of bioartificial tissues and consequently for clinical application. To circumvent insufficient vascularization, the surgically induced angiogenesis by means of arteriovenous loops (AVL) represents a highly effective methodology. Here, previously established hydrogels consisting of nano-fibrillary recombinant eADF4(C16) were transferred into Teflon isolation chambers and vascularized in the rat AVL model over 4 weeks. To improve vascularization, also RGD-tagged eADF4(C16) hydrogels were implanted in the AVL model over 2 and 4 weeks. Thereafter, the specimen were explanted and analyzed using histology and microcomputed tomography. We were able to confirm biocompatibility and tissue formation over time. Functionalizing eADF4(C16) with RGD-motifs improved hydrogel stability and enhanced vascularization even outperforming other hydrogels, such as fibrin.