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Biomedical subjects

N A Johnson

Publications and source records attributed to N A Johnson.

61 records · Page 4Linked to original sources
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Liquid chromatographic fluorescence method for the determination of thiabendazole residues in green bananas and banana pulp.

A novel liquid chromatographic method was developed for the determination of thiabendazole (TBZ) residues in whole green bananas and ripe banana pulp. TBZ is extracted from the banana matrix with ethyl acetate, followed by cleanup of extract on a cation-exchange, solid-phase extraction column. The extract is analyzed for TBZ residues by column liquid chromatography using a cation-exchange column with fluorescence detection. Recoveries of TBZ from whole green bananas fortified with TBZ at 0.05-10 ppm and from ripe banana pulp fortified with TBZ at 0.01-2 ppm averaged 93 and 95%, respectively. The following method for monitoring TBZ residues in whole green bananas and ripe banana pulp is simple, rapid, and sensitive.

Acetates↗
PubMedDate not supplied

Population-based health promotion: a new agenda for public health nurses.

The role of Public Health Nurses (PHNs) involves participation in the development and implementation of population-based health promotion activities. To support encourage and facilitate such participation, the Nursing Division of the Hamilton-Wentworth Department of Public Health Services initiated a "New Agenda" that would help to realize these PHN roles. The New Agenda involved a commitment by the Nursing Division to support population-based health promotion activities by PHNs through changes in Nursing Division policies and practices, and the advancement of a consensus among PHNs regarding the practice of population-based health promotion. A series of four workshops were designed and introduced to ensure that structural barriers to developing PHN roles were eliminated. PHNs stated they achieved role clarification and role acceptance through the New Agenda interventions.

Attitude of Health Personnel↗
PubMedDate not supplied

Determination of thiabendazole residues in white and sweet potatoes by liquid chromatography with fluorescence detection.

A liquid chromatographic (LC) method was developed for determination of thiabendazole (TBZ) residues in or on whole, unwashed white potatoes (Solanum tuberosum) and sweet potatoes (Ipomoea batatas). TBZ is extracted from the potato homogenate with ethyl acetate and the extract purified and concentrated on a cation-exchange, solid-phase extraction column. The extract is analyzed for TBZ residues by column LC with a cation-exchange column and fluorescence detection. Recoveries of TBZ from whole white potatoes fortified with TBZ at 0.05-20 ppm and from whole sweet potatoes fortified with TBZ at 0.005-0.1 ppm averaged 100 and 94%, respectively. The method is also applicable for quantitation of TBZ residues in white potato waste (dried peel) used as an animal feed additive. The present method for monitoring TBZ residues in white and sweet potatoes and white potato waste (dried peel) is simple, rapid, and sensitive.

Chromatography, Liquid↗
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Liquid chromatographic method for determination of total avermectin B1 and 8,9-Z-avermectin B1 residues in hops.

A liquid chromatographic method has been developed and validated for determination of avermectin B1 and 8,9-Z-avermectin B1 residues in dried hops. The dried hops are rehydrated and subsequently extracted with a methanol-water mixture. The avermectins are partitioned into hexane and the hexane extract is concentrated (purified) on an aminopropyl solid-phase extraction column. The purified extract is derivatized with trifluoroacetic anhydride, and the derivatized avermectins are analyzed by reversed-phase liquid chromatography with fluorescence detection. Recoveries of the avermectins from dried hops fortified with approximately 5-1000 ng/g avermectin B1a or 8,9-Z-avermectin B1a ranged from 73 to 108% with an overall average recovery of 95%. The limit of quantitation is 5 ng/g (signal-to-noise ratio [S/N] > 10), and the limit of detection is 2 ng/g (S/N > 3) for each analyte. The assay procedure provides a simple, rapid, and sensitive method for monitoring the total avermectin residues in hops.

Chromatography, Liquid↗
PubMedDate not supplied

Determination of thiabendazole residues in whole citrus fruits by liquid chromatography with fluorescence detection.

An existing liquid chromatographic (LC) method for determination of thiabendazole (TBZ) residues in or on whole green bananas and potatoes was applied to whole, unwashed citrus fruits. The method is applicable for determining TBZ residues in whole oranges, grapefruits, tangerines, and lemons. TBZ is extracted from citrus homogenate with ethyl acetate, and the extract is cleaned up on a cation-exchange, solid-phase extraction column. The purified extract is analyzed by LC with a cation-exchange column and fluorescence detection. Average recovery of TBZ from whole citrus fruits fortified with TBZ at 0.05-20 ppm was 96%. The assay provides a simple, rapid, and sensitive method for monitoring TBZ residues in whole citrus fruits.

Chromatography, Ion Exchange↗
PubMedDate not supplied

Penetrating BB shot head wound in an asymptomatic 9-year-old girl: the ultimate teaching moment.

BACKGROUND: Air rifle BB injuries represent a common type of childhood accident. The purpose of this case report is to encourage all providers of pediatric care to include nonpowder firearm safety education with standard well-child anticipatory guidance. METHODS: A case report is described and experience with similar injuries is discussed from cases found in a literature review using the key words "air rifle," "patient education," "pediatric," "ballistics," and "trauma." RESULTS: A 9-year-old girl came to the emergency department after having been accidentally shot in the head by her 7-year-old brother with a toy air rifle. The BB shot entered through the left cheek and traversed up into the soft tissue above the mandible, just medial to the internal carotid artery, and posterior to the facial nerve. Other than local pain, she was entirely asymptomatic. The cheek was repaired without complication. Conservative therapy was recommended. She and her family were given anticipatory guidance, and her course thereafter was uneventful. CONCLUSION: Firearm education is not a standard part of every well-child encounter. Injuries by all types of firearms are increasing at epidemic rates. Questioning about the accessibility of both powder- and non-powder-based weapons (ie, air rifle) and providing routine safety education should become the standard of care at all well-child encounters.

Child↗