Abstract: A compound of formula (I): wherein: R1 is selected from (i) H, (ii) C3-6cycloalkyl, (iii) C3-7heterocyclyl optionally substituted with a group selected from: methyl and ester, and (iv) linear or branched C1-4alkyl optionally substituted with a group selected from: alkoxy, amino, amido, acylamido, acyloxy, alkyl carboxyl ester, alkyl carbamoyl, alkyl carbamoyl ester, phenyl, phosphonate ester, C3-7heterocyclyl optionally substituted with a group selected from methyl and oxo, and a naturally occurring amino acid, optionally N-substituted with a group selected from methyl, acetyl and boc; A1 is CRA or N; A2 is CRB or N; A3 is CRC or N; A4 is CRD or N; where no more than two of A1, A2, A3, and A4 may be N; one or two of RA, RB, RC, and RD, (if present) are selected from H, F, Cl, Br, Me, CF3, cyclopropyl, cyano, OMe, OEt, CH2OH, CH2OMe and CH2NMe2; the remainder of RA, RB, RC, and RD, (if present) are H; Y is O, NH or CH2; RY is selected from: (RYA) and (RYB).

Abstract: An anchor nail for use with gypsum and other cementitious or composite materials used in roofing which includes a tapered tubular shank having openings therein through which ends of an insert wire staple are deflected to provide an anchoring for the nail within the material and wherein the legs of the staple are formed so as to prevent fastener withdrawal.

Abstract: A silencer for relatively low horsepower combustion engines is constructed with two separate sections in series through which exhaust gases pass. The upstream section has two concentric perforated tubes within an imperforate jacket with exhaust openings from the tubes discharging into a vestibule. From the vestibule gases are directed in a circumferential path as they enter a second series of concentric perforated tubes within the jacket, the gases being passed first to a chamber between the jacket and the outermost tube and from there through perforations in the walls of the tubes to an exhaust outlet port.