Abstract: A &bgr;-lactam compound of the formula: wherein R1 is lower alkyl or OH-substituted lower alkyl, R2 is H or lower alkyl, X is O, S or NH, n is 1 to 3, R3 is —C(Ra)═NH (Ra is H, lower alkyl or substituted lower alkyl), or a salt thereof, or an ester thereof. These compounds show excellent antibacterial activity against Gram-positive bacteria, particularly against methicillin-resistant Staphylococci and methicillin-resistant and coagulase-negative Staphylococci.

Abstract: A compound of the formula: ##STR1## , which is useful as an antimicrobial agent.

Abstract: A magnetic recording flexible disc composed of a polyester film substrate having formed thereon a magnetic layer, the improvement wherein said polyester film is a biaxially oriented film consisting of poly-1,4-cyclohexylene dimethylene terephthalate wherein at least 90 mole % of a glycol component is 1,4-cyclohexanedimethanol and at least 80 mole % of an acid component is terephthalic acid, a maximum value of a temperature dependent expansion in the surface direction of the film is 9.times.10.sup.-6 to 35.times.10.sup.-6 /.degree.C., a maximum value of a humidity dependent expansion in the surface direction of the film is 0 to 8.0.times.10.sup.-6 /% RH, the difference between the maximum and minimum values of the temperature dependent expansion in the surface direction of the film is 0 to 8.0.times.10.sup.-6 /.degree.C., and the difference between the maximum and minimum values of the humidity dependent expansion in the surface direction of the film is 0 to 3.0.times.10.sup.-6 /% RH.

Abstract: A process for producing a film of a thermoplastic resin, characterized in that the rotation of a cooling drum for cooling a molten film-like extrudate is controlled such that the variation rate (%) of instantaneous rotation under no load (as defined in the specification) is less than about 1%, and that the cooled film-like extrudate is withdrawn from the cooling drum so that substantially no tension in the subsequent stretching step is exerted on the film-like extrudate on the cooling drum. The process is preferably applicable to a film-forming apparatus which operates at high speeds. A film having markedly reduced thickness unevenness is produced.