Use of Chitosan-Siloxane Porous Hybrid Scaffold as Novel Burr Hole Covers

Chitosan-siloxane porous hybrids have high potential as tissue scaffolds. This manuscript focuses on the regeneration of skull bone after a burr hole. This was done using hybrids incorporated with calcium or coated with hydroxyapatite after soaking in a phosohate solution. The specimens fitted the burr hole and the cells migrated into the pores form surrounding bone tissue. After implanation no inflammation was observed and the specimens degraded 12 months later. A coating of hydroxyapatite accelerated bone formation compared

Structures of Organic Additives Modified Magnetite Nanoparticles

Magnetite (Fe3O4) nanoparticles and magnetite-based inorganic–organic hybrids are attracting increasing attention in biomedicine, as thermoseeds for hyperthermia and contrast media in magnetic resonance imaging. Controlling the size of Fe3O4 thermoseeds is important, as particle size affects their heat generation under alternative magnetic fields. Fe3O4 is easily synthesized via aqueous processes. We previously demonstrated that adding organic polymers during synthesis affected the size and crystallinity of the resulting Fe3O4. However, the relationship of the chemical structure of the low-molecular-weight organic additive of its effect on the product has not been elucidated. In this study, organic compounds containing varying functional groups and surface charges were added to the precursor solution of Fe3O4. Crystalline Fe3O4 formed in the presence of neutral acetone, cationic ethylenediamine, and anionic acetic acid. These nanoparticles had slightly smaller particle sizes than those prepared in the absence of additives. The presence of oxalic acid and tris(hydroxymethyl)aminomethane inhibited Fe3O4 nucleation, instead yielding lepidocrosite- or akaganeite-type FeOOH. These differences were attributed to the ability to form complexes between iron ions and the organic additives. The saturation magnetizations of the products were consistent with Fe3O4. This indicated that the crystal phase of the iron oxide products differed, even when prepared in the presence of organic additives of the same functional group. It is concluded that state of ion-organic molecule complex in the solutions is a key factor governing nanostructure of the resultant iron oxide

Diurnal Variation of Human Sweet Taste Recognition Thresholds Is Correlated With Plasma Leptin Levels

OBJECTIVE—It has recently been proposed that the peripheral taste organ is one of the targets for leptin. In lean mice, leptin selectively suppresses gustatory neural and behavioral responses to sweet compounds without affecting responses to other taste stimuli, whereas obese diabetic db/db mice with defects in leptin receptor lack this leptin suppression on sweet taste. Here, we further examined potential links between leptin and sweet taste in humans

Detailed secondary structure models of invertebrate 7SK RNAs

<p>The 7SK RNA is a small nuclear RNA that is involved in the regulation of Pol-II transcription. It is very well conserved in vertebrates, but shows extensive variations in both sequence and structure across invertebrates. A systematic homology search extended the collection of 7SK genes in both Arthropods and Lophotrochozoa making use of the large number of recently published invertebrate genomes. The extended data set made it possible to infer complete consensus structures for invertebrate 7SK RNAs. These show that not only the well-conserved 5′- and 3′- domains but all the interior Stem A domain is universally conserved. In contrast, Stem B region exhibits substantial structural variation and does not adhere to a common structural model beyond phylum level.</p