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    Abstract:
    DNA can be measured in mammalian tissues by extracting deoxyribose from unfixed, lyophilized tissue specimens with 0.5 N perchloric acid at 90 degrees C. Deoxyribose concentrations in the extract are determined photometrically by reaction with diphenylamine. Inevitably, some deoxyribose is destroyed during exposure to the hot acid. A computer program has been written which corrects photometric absorbance data for such loss of deoxyribose. When extrapolated to infinite duration of extraction, the corrected absorbances yield a measure of the DNA content of the specimen. This method was used to estimate DNA concentrations in human cerebellar cortex and white matter. The results are discussed in relation to stable carbon isotope ratios of human cerebellar DNA.
    Keywords:
    Deoxyribose
    Perchloric acid
    Absorbance
    Browning
    Diphenylamine
    The effect of the diphenylamine-treatment on the core browning and physiological changes of ‘Ya-Li’ pears stored at 0℃ were studied in this paper. The results showed that the fruits treated at 0℃ appeared serious core browning at early-period storage. The index of core browning at early-period storage decreased markedly after 60 d, the index of core browning of DPA-treated fruits was 0.233,and that of the control was 0.417; meanwhile, ethylene production was cut down,activity of PPO was restrained, content of phenolics was maintained and content of malondialdehyde was affected with diphenylamine-treatment.
    Diphenylamine
    Browning
    Malondialdehyde
    Citations (0)
    Diphenylamine
    Deoxyribose
    Cytosine
    Trichloroacetic acid
    Citations (1)
    In the presence of acid, the 2-deoxypentose of DNA is converted to beta-hydroxylevulinaldehyde which reacts with diphenylamine to give blue color, which is estimated by UV spectrophotometer or by colorimeter at 595 nm. Since only deoxyribose of purine nucleotide reacts, the value obtained represents only half to total amount.
    Diphenylamine
    Deoxyribose
    Colorimeter
    Bleach
    Value (mathematics)
    Abstract A separatory funnel procedure is presented that separates diphenylamine (DPA) from Ext. D&C Yellow No. 1. The DPA is extracted from the color with isooctane and the amount of DPA is determined spectrophotometrically. Recoveries of 0.02–1 % added DPA ranged from 95.5 to 104%.
    Diphenylamine
    Citations (0)
    Current sitation at home and abroad,production methods and uses of diphenylamine were described.It was suggested that continuous condensation of aniline be used,plant for production of diphenylamine be constructed as soon as possible to meet the increasing need of diphenylamine.
    Diphenylamine
    Citations (0)
    Summary Dips of diphenylamine 1,000 p.p.m. in aqueous alcoholic solution controlled superficial scald on 11 varieties of apples, but not on Statesman. A similar formulation applied as a spray to fruit in cases was equally successful, but some damage occurred to the bottom fruit where drainage was incomplete. Paper wraps containing DPA completely controlled scald in Granny Smith apples. Oiled wraps did not give adequate control of scald in immature, early pieked fruit. Phenothiazine 1,000 and 2,000 p.p.m. did not control scald and caused damage to some varieties. Several other unsuccessful materials are noted. Diphenylamine does not aggravate other storage disorders, and there is some evidence that it may reduce both internal breakdown and core flush.
    Diphenylamine