Effect of p-aminosalicylic acid (PAS) on the loss of acid-fastness produced in tubercle bacilli by isoniazid

The microbiological assay method for estimating free isoniazid in serum described by Mandel et al. (1956), used as the assay end-point the dilution pro-ducing loss of acidfastness in 50 per cent of bacilli. The advantage of this end point is that loss of acidfastness is produced specifically by isoniazid, and not by either PAS (Mandel et al., loc. cit.) or streptomycin (Middlebrook, 1952). Mandel et al. (loc. cit.) claimed that the addition of as much as 1,000 mg./c.c. of PAS to undiluted human sera did not interfere with the assay of isoniazid in the serum using loss of acid-fastness as the end-point. Since Mandel et al. (loc. cit.) did not however, describe their results fully, it remained a possibility that PAS in con-centrations near that necessary to inhibit the growth of tubercle bacilli c ould act synergestically or antagonistically with isoniazid in producing loss of acid-fastness. This was investigated in the following experiments

Phosphorus-containing imide resins

Bis- and tris-imides derived from tris (m-aminophenyl) phosphine oxides by reaction with maleic anhydride or its derivatives, and addition polymers of such imides, including a variant in which a mono-imide is condensed with a dianhydride and the product is treated with a further quantity of maleic anhydride. Such monomers or their oligomes may be used to impregnate fibers and fabrics which when cured, are flame resistant. Also an improved method of producing tris (m-aminophenyl) phosphine oxides from the nitro analogues by reduction with hydrazine hydrate using palladized charcoal or Raney nickel as the catalyst is described

Elastomer-modified phosphorus-containing imide resins

Phosphine oxide-containing polyimide resins modified by elastomers, are disclosed which have improved mechanical properties. These products are particularly useful in the production of fiber or fabric-reinforced composites or laminates

Phosphorus-containing imide resins

Cured polymers of bis and tris-imides derived from tris(m-aminophenyl) phosphine oxides by reaction with maleic anhydride or its derivatives, and addition polymers of such imides, including a variant in which a monoimide is condensed with a dianhydride and the product is treated with a further quantity of maleic anhydride prior to curing are disclosed and claimed. Such polymers are flame resistant. Also disclosed are an improved method of producing tris(m-aminophenyl) phosphine oxides from the nitro analogues by reduction with hydrazine hydrate using palladized charcoal or Raney nickel as the catalyst and fiber reinforced cured resin composites

Phosphorus-containing bisimide resins

The production of fire-resistant resins particularly useful for making laminates with inorganic fibers such as graphite fibers is discussed. The resins are by (1) condensation of an ethylenically unsaturated cyclic anhydride with a bis(diaminophenyl) phosphine oxide, and (2) by addition polymerization of the bisimide so obtained. Up to about 50%, on a molar basis, of benzophenonetetracarboxylic acid anhydride can be substituted for some of the cyclic anhydride to alter the properties of the products. Graphite cloth laminates made with these resins show 800 C char yields greater than 70% by weight in nitrogen. Limiting oxygen indexes of more than 100% are determined for these resins

Heavy-Fermions in a Transition-Metal Compound: LiV2O4LiV_2O_4

The recent discovery of heavy-Fermion properties in Lithium Vanadate and the enormous difference in its properties from the properties of Lithium Titanate as well as of the manganite compounds raise some puzzling questions about strongly correlated Fermions. These are disscussed as well as a solution to the puzzles provided.Comment: late