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Biomedical subjects

D B Ward

Publications and source records attributed to D B Ward.

6 recordsLinked to original sources
PubMed2005

Continuous extraction and destruction of chloro-organics in wastewater using ozone-loaded Volasiltrade mark245 solvent.

Extracting waterborne contaminants to ozone-loaded Volasiltrade mark245 (a siloxane solvent in which ozone is ten times more soluble than water) has been studied as a means of enhancing reaction kinetics and thus, providing more rapid wastewater decontamination. Investigation was carried out with respect to 2-chlorophenol and dichloromethane. Using a pilot scale continuous flow liquid-liquid/ozone water treatment system, 2-chlorophenol was extracted to the ozone-loaded solvent phase and considerable extents of destruction were achieved. However, the approach was demonstrated to yield slightly less destruction than direct gas contact for the same utilization of ozone and enhanced reaction kinetics were not shown to occur. This was suggested to be due to increased interfacial mass transfer resistance and/or the promotion of less destructive reaction pathways. Modification of the existing pilot system, by conversion from co- to counter-current solvent-loading, enabled greater dissolved ozone concentrations to be achieved within the solvent. Increasing the counter-current exchange column height to approximately 2.5m was suggested for achieving a near optimum level of performance. The liquid-liquid/ozone approach was demonstrated to be an effective means of indirectly exposing wastewater contaminants to concentrated ozone. As such the technology may be applicable as an alternative to direct gas contact in instances where the avoidance of contaminant sparging is desired (i.e. where contaminants are highly volatile, pungent and/or toxic) or foaming occurs.

Chlorophenols↗
PubMed2000

Characterization of diaper dermatitis in the United States.

BACKGROUND: Diaper dermatitis is the most common dermatologic disorder of infancy. This study evaluates the frequency of outpatient visits resulting in this diagnosis, specialties of physicians providing services, demographics of patients, and leading agents used in treatment. DESIGN: Records of 272,841 encounters from the National Ambulatory Medical Care Survey (1990-1997) were examined for visits in which diaper dermatitis was diagnosed in children. The likelihood of diagnosis in the general pediatric population was calculated and the leading treatment agents were ranked. RESULTS: There were approximately 8.2 million visits in which diaper dermatitis was diagnosed. For the pediatric population in the at-risk age range, there was a 1 in 4 likelihood of being diagnosed with the skin disorder. Pediatricians provided 75% of services for the treatment of diaper dermatitis; the demographics of patients were similar to those of comparably aged individuals in the general population. Nystatin was the leading treatment agent prescribed (27% of visits), followed by clotrimazole (16%), a combination product of nystatin and triamcinolone (16%), hydrocortisone (8%), and a combination product of clotrimazole and betamethasone dipropionate (6%). CONCLUSIONS: Visits for diaper dermatitis are frequent, and pediatricians are the physicians most often called on to provide treatment. No portion of the pediatric population is disproportionately diagnosed. The frequent use of potent corticosteroids contained in combination agents is a potential target for improving the management of diaper dermatitis.

Administration, Topical↗
PubMed1967

Changes in the chemical composition and the enzymic activities of hepatic microsomes of the chick embryo during development.

1. The values of the protein, RNA and phospholipid concentrations within the total microsomal fractions obtained from different stages of embryonic chick liver are compared. 2. Only the phospholipid content increases significantly with increasing developmental age. 3. The lack of membranes in the early stages of development and the relative constancy of RNA values during development suggests that some of the protein present at the early developmental stages is of a non-membranous non-ribosomal nature. 4. Glucose 6-phosphatase, adenosine triphosphatase, NADH(2)-cytochrome c reductase and diaphorase all increased in activity as development progressed. 5. Comparisons of submicrosomal fractions with respect to their protein, RNA and phospholipid content showed that in all embryonic stages fraction II (rough-membrane fraction) contained more than 60% of the proteins, RNA and phospholipid of the microsomal fraction. 6. Glucose 6-phosphatase was shown to be present predominantly in fraction II, whereas adenosine triphosphatase was present predominantly in fraction Iab (smooth-membrane fraction). 7. The significance of the differences between the smooth- and rough-microsomal fractions is discussed.

Animals↗
PubMed1967

The phospholipid composition of embryonic chick liver microsomes.

1. The phospholipid composition of hepatic microsomal fractions from different developmental stages of embryonic chick was established. The major components were phosphatidylcholine (approx. 66%), phosphatidylethanolamine plus phosphatidylserine (approx. 21%) and sphingomyelin (approx. 9%). 2. There were no significant changes in the phospholipid composition during embryonic development from 9 to 20 days. 3. When microsomal subfractions were prepared it was found that the smooth-microsomal fractions (Ia and Ib) had a significantly greater sphingomyelin content than the rough-microsomal fraction (II). This was compensated by a lower phosphatidylcholine content in fractions Ia and Ib and an increase of phosphatidylcholine in fraction II. 4. The significance of the differences in the phospholipid composition of smooth and rough microsomes is discussed with particular reference to the origin and interrelation of smooth and rough endoplasmic reticulum.

Aging↗