Structure Determination of an Endogenous Sleep-Inducing Lipid, cis-9-Octadecenamide (Oleamide): A Synthetic Approach to the Chemical Analysis of Trace Quantities of a Natural Product
摘要:
The pursuit of endogenous sleep-inducing substances has been the focus of an extensive, complicated body of research. Several compounds, including Delta-sleep-inducing peptide and prostaglandin D-2, have been suggested to play a role in sleep induction, and yet, the molecular mechanisms of this physiological process remain largely unknown. In recent efforts, the cerebrospinal fluid of deep-deprived cats was analyzed in search of compounds that accumulated during sleep deprivation. An agent with the chemical formula C18H35NO was found to cycle with sleep-wake patterns, increasing in concentration with sleep deprivation and decreasing in amount upon recovery sleep. Since the material was generated in minute quantities and only under the special conditions of sleep deprivation, efforts to isolate sufficient material for adequate characterization, structure identification, and subsequent detailed evaluation of its properties proved unrealistic. With the trace amounts of the impure endogenous compound available, extensive MS studies on the agent were completed, revealing key structural features of the molecule including two degrees of unsaturation, a long alkyl chain, and a nitrogen substituent capable of fragmenting as ammonia. Additionally, HPLC traces suggested a weak UV absorbance for the unknown material. With this data in hand and encouraged by the relatively small size of the molecule, MW = 281, a synthetic approach toward the structural identification of the natural compound was initiated. Herein, we report the full details of the synthesis and comparative characterization of candidate structures for this endogenous agent that led to the unambiguous structural correlation with synthetic cis-9-octadecenamide.
[Problem] A polyolefin composition comprising an olefin-based thermoplastic elastomer which is superior to conventional olefin-based thermoplastic elastomers in scratch resistance and abrasion resistance and has excellent heat aging resistance is proposed.
[Means for Solving the Problem] A polyolefin composition comprising a syndiotactic α-olefin-based copolymer (A), a polyolefin resin (B) (other than polybutene (C)), polybutene (C), and if necessary, an ethylene-based copolymer rubber (D).
THERMOPLASTIC ELASTOMER COMPOSITION FOR FOAMING, MOLDED FOAM THEREOF, COMPOSITE MOLDED PRODUCT USING THE MOLDED FOAM, AND INSTRUMENT PANEL FOR AUTOMOBILE
申请人:KURITA Hayato
公开号:US20110117358A1
公开(公告)日:2011-05-19
[Problem] To provide a thermoplastic elastomer composition for foaming, which has sufficient foamability and provides a molded article having good appearance.
[Solution to Problem] A thermoplastic elastomer composition for foaming, which comprises 10 to 40% by weight of a partially or completely crosslinked ethylene/α-olefin/non-conjugated polyene copolymer rubber (A) comprising ethylene, an α-olefin of 3 to 20 carbon atoms and a non-conjugated polyene, 3 to 33% by weight of an ethylene/α-olefin copolymer (B) comprising ethylene and an α-olefin of 3 to 20 carbon atoms, 10 to 40% by weight of polypropylene (C) having a melting point, as determined by differential scanning calorimetry (DSC), of 40 to 170° C., 10 to 45% by weight of a softener (D) for rubbers, and at least one substance selected from an isotactic propylene-based polymer (E-a) in an amount of 1 to 30% by weight and a syndiotactic α-olefin-based copolymer (E-b) in an amount of 1 to 20% by weight, with the proviso that the total amount of the components (A), (B), (C), (D), (E-a) and (E-b) is 100% by weight.
Process for producing pre-expanded particles of a polyolefin
申请人:SUMITOMO CHEMICAL COMPANY, LIMITED
公开号:EP0323719A2
公开(公告)日:1989-07-12
A process for producing pre-expanded particles of a thermoplastic resin, wherein said particles are of a polyolefin obtained by polymerizing an olefin in the presence of a Ziegler-Natta catalyst, and contain not more than 1% by weight of particles of diameter up to 105 µm and having a particle size distribution represented by:R(Dp) = 100exp[-(Dp/De)n] where Dp is300 or more and represents a particle diameter (µ m); R(Dp) represents a cumulative weight percentage; De represents an absolute size constant that is a particle diameter (µm) corresponding to R(Dp) 36.8% by weight; and n is 25 or more and is a distribution constant.
The process can be carried out by dispersing the particles in a liquid medium (e.g. water) containing a blowing agent (e.g. an aliphatic hydrocarbon) and a phenolic antioxidant, heating to above the softening point of the polymer, and releasing the dispersion into a zone of lower pressure.
Pre-expanded polyolefin particles free from scatters of cell diameter or particle diameter and having a high expansion ratio are obtained, which can be put into a mold for expansion molding to easily provide a uniformly expanded article.
Container bodies for a photographic film cartridge which has solved white powder generation problem by devising the Rockwell hardness, a blend of lubricants, a blend of polypropylene resins or a combination of a particular resin composition and groove formation. While, moistureproofness can be improved by thickening the gate mark portion.
Compositions stabilisées de polyacétals et procédé pour leur fabrication
申请人:SOLVAY
公开号:EP0421973A1
公开(公告)日:1991-04-10
L'invention concerne une composition stabilisée de polyacétals comprenant un anti-oxydant phénolique, un copolymère d'éthylène et d'alcool vinylique et un amide aliphatique.
L'invention concerne également un procédé de fabrication de cette composition.