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L L Barton

Publications and source records attributed to L L Barton.

At least 37 records · Page 2Linked to original sources
PubMed1998

Removal of U and Mo from water by immobilized Desulfovibrio desulfuricans in column reactors.

Intact cells of Desulfovibrio desulfuricans were immobilized in polyacrylamide gel and used to remove soluble U and Mo from water by enzymatically mediated reduction reactions in column reactors. Formate or lactate served as the electron donor and oxidized U(VI) and Mo(VI) species served as electron acceptors. Greater than 99% removal efficiencies were achieved for both metals with initial concentrations of 5 mg/L U and 10 mg/L Mo. Hydraulic residence times in the columns were between 24 and 36 h. Sulfate concentrations as high as 2000 mg/L did not inhibit reduction of U or Mo in the columns. However, nitrate inhibited uranium reduction at concentrations near 50 mg/L and inhibited molybdenum reduction at concentrations near 150 mg/L. The results indicate that enzymatic reduction of U and Mo by immobilized cells of D. desulfuricans may be a practical method for removing these contaminants from solution in continuous-flow reactors.

Bioreactors↗
PubMed1998

Reduction of Cr, Mo, Se and U by Desulfovibrio desulfuricans immobilized in polyacrylamide gels.

Intact cells of Desulfovibrio desulfuricans, immobilized in polyacrylamide gel, removed Cr, Mo, Se and U from solution by enzymatic-mediated reduction reactions. Lactate or H2 served as the electron donor and the oxidized Cr(VI), Mo(VI), Se(VI) and U(VI) served as electron acceptors. Reduction of the oxidized metal species resulted in the precipitation of solid phases of the metals. Metal removal efficiencies of 86-96% were achieved for initial concentrations of 1 mM Mo, Se, and U and 0.5 mM Cr. Insoluble metal phases accumulated on both the surface and the interior of the polyacrylamide gel. In column tests conducted for U removal, effluent concentrations less than 20 micrograms L(-1) were achieved with initial concentrations of 5 mg L(-1) and 20 mg L(-1) U and residence times from 25-37 h. The enzymatic reduction of Cr, Mo, Se, and U by immobilized cells of D. desulfuricans may be a practical method for removing these metals from solution in a biological reactor.

Acrylic Resins↗
PubMed1998

Gastrointestinal complications of chronic granulomatous disease: case report and literature review.

Chronic granulomatous disease (CGD), an inherited disorder of phagocytic leukocyte function, is characterized by recurrent infections with catalase-positive organisms. Gastrointestinal (GI) tract involvement, present in the majority of affected individuals, may be present initially and recurrently, mimics other entities such as inflammatory bowel disease, and causes substantive morbidity and mortality. Disorders of motility, ulceration, obstruction, and infection (e.g., abscesses) occur from the mouth to the anus and stereotypically manifest with vomiting, diarrhea, abdominal pain, weight loss, and fever. Careful physical examination, in concert with appropriate diagnostic studies, is necessary to delineate intraabdominal pathologic processes. Abdominal radiographs, ultrasonography, computerized tomography, and endoscopy are useful ancillary diagnostic procedures. Drainage of accessible abscesses, antimicrobial therapy based on organisms cultured from blood and tissue, and interferon gamma may lead to suppression or eradication of infections and resolution of symptoms. Corticosteroids are useful for gastric outlet obstruction and sulfasalazine and cyclosporine for large bowel disease. Gallbladder dysfunction may be ameliorated, as in our patient, with administration of cholestyramine.

Child, Preschool↗
PubMed1997

Pediatric morning report: an appraisal.

We examined and contrasted morning reports at two hospitals, university and community, that have a pediatric residency program. Patient diagnoses assigned at morning report were compared with final diagnoses to assess disease categories discussed and the value of including outpatient follow-up in this educational forum. Data were obtained during morning reports for 6 months by chief residents at university and private community hospitals. Pertinent history, physical examination, and laboratory and radiologic findings were recorded and were assigned a tentative morning report diagnosis based on morning report discussion. Cases were then reviewed at discharge and at 6 months to determine final diagnoses. At the university hospital, 58% of the cases were undiagnosed before presentation at morning report. Of those cases, 23% were assigned a diagnosis at morning report that differed from the final diagnosis. Similarly, at the private community hospital, 28% of cases were undiagnosed before presentation at morning report. Of those cases, 73% were assigned a diagnosis that differed from the final diagnosis. We conclude that the provision of follow-up at morning report is important for maximizing resident education.

Child↗
PubMed1997

An analysis of morning report at a pediatric hospital.

The purpose of this study was to determine the types of cases residents select for morning report discussion and the educational value of postdischarge follow-up of unknown cases. Between April and December of 1994, at Cardinal Glennon Children's Hospital in St. Louis, Missouri, random, resident, and group-selected patients listed at morning report were followed up throughout hospitalization. Patients were categorized based upon whether or not their morning report and discharge diagnoses were the same or different. Patients discharged without a diagnosis were followed up by chart review at 6 months to determine whether a diagnosis had been made. Data were analyzed by Chi-square analysis with Bonfferoni adjustment factor for multiple comparisons. Residents were more than two times more likely to select cases for discussion in which the diagnosis changed during hospitalization (P < 0.01). The 6-month follow-up yielded new diagnoses in only 21% of previously unknown cases. We concluded that residents do an exceptional job of selecting difficult diagnostic cases for discussion at morning report. Postdischarge follow up of unknown cases adds little new information for discussion at morning report.

Child↗