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F Feng

Publications and source records attributed to F Feng.

60 records · Page 4Linked to original sources
PubMed1989

[Simultaneous determination of four components in vitamin B compound tablets by Kalman filtering spectrophotometry].

The four principal components, vitamin B1, B2, B6 and nicotinamide in vitamin B compound tablet show certain instabilities individually and the amounts of these components differ considerably in the tablets, so their simultaneous determination without prior separation is usually difficult. This paper deals with the feasibility of using Kalman filtering spectrophotometry to do so, and makes some efforts concerning the deviation from the Beer-Lambert law due to mutual effects among the acting molecules. The results obtained were comparatively satisfactory both in precision and in accuracy. The average recovery of vitamin B1, B2, B6, and nicotinamide were 100.2 +/- 0.90% (CV), 100.3 +/- 1.7% (CV), 101.1 +/- 3.3% (CV), 99.90 +/- 0.65% (CV) respectively and were better than those in previous reports. All these show that the use of Kalman filtering spectrophotometry to the assay of vitamin B compound tablets is feasible.

Niacinamide↗
PubMed1966

Pantothenate and coenzyme A in bacterial growth.

Toennies, G. (Temple University School of Medicine, Philadelphia, Pa.), D. N. Das, and F. Feng. Pantothenate and coenzyme A in bacterial growth. J. Bacteriol. 92:707-713. 1966.-The effect of environmental pantothenate levels on the growth of Streptococcus faecalis 9790 was studied in terms of growth rate, depletion phenomena, cellular coenzyme A (CoA) content, and differential rates of wall and membrane synthesis. Low concentrations of pantothenate yielded normal exponential growth curves up to peak turbidities which are a function of pantothenate concentration. Attainment of these peaks was followed by lysis. Under such conditions, bacterial CoA increased initially in proportion with cell substance, but attained a peak level much earlier than cell substance, and then gradually decreased down to vanishing amounts. With higher pantothenate concentrations, cellular CoA levels increased to a maximum, and, under these conditions, the CoA content remained constant during exponential growth. Four-fifths of the pantothenate requirement of growing cells was eliminated by environmental oleate and palmitate. When CoA disappeared during growth on low pantothenate levels, cell wall synthesis seemed to continue at nearly normal rates, but membrane synthesis was severely curtailed. The data suggest that in fermentative organisms pantothenate action might be confined to wall and membrane synthesis, that these two processes differ in their quantitative dependence on pantothenate, and that pantothenate might occur in the form of acyl carrier protein as well as CoA.

Cell Wall↗