Developing and fully developed turbulent flow of drag reducing fluids in an annular duct

Velocity profiles for the inner and outer flow regions of annuli are proposed for the turbulent flow of drag reducing fluids. Theoretical expressions for friction factors are developed. From the shear stress equations and the velocity profiles, estimates for the entrance lengths are given.     

Elastic effects in the flow of polymer solutions in channels of variable cross section and a porous medium

The manifestation of elastic effects during the filtration of polymer solutions is analyzed theoretically.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 49, No. 3, pp. 390–397, September, 1985.     

Relevance of pharmacokinetics and pharmacodynamics

This ex post facto study investigated the relationship of social support from two workplace sources, unit managers and registered nurse (RNs) coworkers, to work-related stress among staff nurses. Sample participants included 51 full-time RNs from a variety of clinical specialties in one nursing organization. The three theoretical components--affect, affirmation, and aid--were measured by the Norbeck Social Support Questionnaire. The Nursing Stress Scale was used to quantify the levels of perceived work-related stress. Statistically significant negative correlations were found between affect from unit managers (r = -299; P = 0.15) and aid from coworkers (r = -.294; P = .036) on levels of perceived work-related stress. Additionally, the increased age of the subjects (r = -.342; P = .007), years of nursing experience (r = -252; P = .037), and length of employment (r = -329; P = .009) had a negative relationship with work stress. The results of this research demonstrated that two components of social support--affect (emotional support) from unit managers and aid (services, information, materials) from coworkers--were linked to lower stress scores in this sample of staff nurses.     

Purification, characterization, and mechanism of a flavin mononucleotide-dependent 2-nitropropane dioxygenase from Neurospora crassa

A nitroalkane-oxidizing enzyme was purified to homogeneity from Neurospora crassa. The enzyme is composed of two subunits; the molecular weight of each subunit is approximately 40,000. The enzyme catalyzes the oxidation of nitroalkanes to produce the corresponding carbonyl compounds. It acts on 2-nitropropane better than on nitroethane and 1-nitropropane, and anionic forms of nitroalkanes are much better substrates than are neutral forms. The enzyme does not act on aromatic compounds. When the enzyme reaction was conducted in an 18O2 atmosphere with the anionic form of 2-nitropropane as the substrate, acetone (with a molecular mass of 60 Da) was produced. This indicates that the oxygen atom of acetone was derived from molecular oxygen, not from water; hence, the enzyme is an oxygenase. The reaction stoichiometry was 2CH3CH(NO2)CH3 + O2-->2CH3COCH3 + 2HNO2, which is identical to that of the reaction of 2-nitropropane dioxygenase from Hansenula mrakii. The reaction of the Neurospora enzyme was inhibited by superoxide anion scavengers in the same manner as that of the Hansenula enzyme. Both of these enzymes are flavoenzymes; however, the Neurospora enzyme contains flavin mononucleotide as a prosthetic group, whereas the Hansenula enzyme contains flavin adenine dinucleotide.