A range of experimental designs have been used in destructive testing of composite resin CAD/CAM crowns. Various materials have been adopted for the abutment in such tests, including human or bovine dentin, stainless steel, PMMA, and composite resin, the selection of which is made in accordance with study objective or preference of the researcher. The purpose of this study was to determine how the material selected for the abutment material affected fracture load and maximum displacement.
View Article and Find Full Text PDFThe preparation of supramolecular hydrogels containing various inorganic acids and salts using L-lysine-based hydrogelators is conducted and their thermal stabilities, gel strengths, FT-IR spectra, and electron micrographs are measured. These hydrogelators can form supramolecular hydrogels over a wide pH range and contain inorganic acids and salts. The supramolecular hydrogels based on ester-type hydrogelators have good thermal stabilities (high Tgel), while the hydrogelator with a carboxyl group forms a thermally sensitive gel with high mechanical strength.
View Article and Find Full Text PDFAn improved high-performance liquid chromatography (HPLC) method was developed for simultaneous analysis of histamine (HA) and tele-methylhistamine (tele-MHA) levels in mouse and rat brain. The method consists of a solid-phase extraction (SPE) and subsequent HPLC with postcolumn derivatization of the amines with o-phthalaldehyde. The recovery rates of HA and tele-MHA during the SPE procedure were 82.
View Article and Find Full Text PDFOrganogels are formed through a conventional organogelation involving a heating process and an in situ organogelation at room temperature. The conventional organogelation is carried out by dissolution of gelators by heating, while the in situ organogelation is performed by mixing of highly reactive methyl 2,6-diisocyanatohexanoate (LDI) or 2-isocyanatoethyl 2,6-diisocyanatohexanoate (LTI) and alkylamines. The in situ organogelation produced the organogels within several seconds after mixing.
View Article and Find Full Text PDFNovel gemini organogelators based on L-lysine, in which two L-lysine derivatives are linked by different alkylene chain lengths through the amide bond, have been simply and effectively synthesized, and their organogelation abilities and thermal stabilities have been investigated. In a series of L-lysine ethyl ester derivatives, the organogelation abilities decreased with increasing alkylene spacer length. In particular, bis(N(epsilon)-lauroyl-L-lysine ethyl ester) oxalyl amide is a good organogelator that gels most organic solvents such as alcohols, cyclic ethers, aromatic solvents and acetonitrile.
View Article and Find Full Text PDFTo clarify the role of the neuropeptide Y (NPY) Y5 receptor subtype in energy homeostasis, the effect of the intracerebroventricular infusion of a selective Y5 agonist, D-Trp(34)NPY, was investigated in C57BL/6J mice. Intracerebroventricular infusion of D-Trp(34)NPY (5 and 10 microg/d) produced hyperphagia and body weight gain, accompanied by increased adipose tissue weight, hypercholesterolemia, hyperinsulinemia, and hyperleptinemia. Oral administration of a selective Y5 antagonist at a dose of 100 mg/kg twice a day completely suppressed all of these D-Trp(34)NPY-induced changes, indicating that chronic activation of the Y5 receptor produces hyperphagia and obesity.
View Article and Find Full Text PDFMelanin-concentrating hormone (MCH) is a cyclic orexigenic peptide expressed in the lateral hypothalamus. Recently, we demonstrated that chronic intracerebroventricular infusion of MCH induced obesity accompanied by sustained hyperphagia in mice. Here, we analyzed the mechanism of MCH-induced obesity by comparing animals fed ad libitum with pair-fed and control animals.
View Article and Find Full Text PDFA family of L-lysine-based low-molecular-weight compounds with various positively charged terminals (pyridinium and imidazolium derivatives) was synthesized and its gelation behavior in water was investigated. Most of the compounds can be very easily synthesized in high yields (total yields >90 %), and they function as excellent hydrogelators that form hydrogels below 1 wt %; particularly, N(epsilon)-lauroyl-N(alpha)-[11-(4-tert-butylpyridinium)undecanoyl]-L-lysine ethyl ester (2 c) and N(epsilon)-lauroyl-N(alpha)-[11-(4-phenylpyridinium)undecanoyl]-L-lysine ethyl ester (2 d), which are able to gel water at concentration of only 0.2 wt %.
View Article and Find Full Text PDFMelanin-concentrating hormone (MCH) is a cyclic amino acid neuropeptide localized in the lateral hypothalamus. Although MCH is thought to be an important regulator of feeding behavior, the involvement of this peptide in body weight control has been unclear. To examine the role of MCH in the development of obesity, we assessed the effect of chronic intracerebroventricular infusion of MCH in C57BL/6J mice that were fed with regular or moderately high-fat (MHF) diets.
View Article and Find Full Text PDFNew L-lysine derivatives with a positively charged terminal can gel water below 1 wt%; particularly, 1a and 2a form a hydrogel at 0.3 wt% corresponding to approximately 12,300 and 12,500 waters/gelator molecule, respectively.
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