Nathan W. Bower

Nutritional evaluation of marama bean, (Tylosema esculentum, Fabaceae): analysis of the seed

Marama bean (Tylosema esculentum, Fabaceae), a potential arid-land legume crop from the Kalahari Desert of Botswana, was analyzed for protein, amino acids, oil, fatty acids, fiber, caloric value, trypsin inhibitor, and mineral content. Results indicate that the bean is adequate in these nutrients for a human diet, but the trypsin inhibitor activity should be destroyed prior to consumption.RésuméBerechnungen betreffend des Ernährungswertes der Marama Bohne (Tylosema esculentum,Fabaceae):Die Analyse der Samen. Die Marama Bohne ist potentiell ein Legumen aus der Kalahari Wüste für Ernten in öden Ländern. Es wurde nach Proteinen, Aminosäuren, Öl, Fettsäuren, Fasern, Heizwert, Trypsin Hemmungstoffen, und anorganischem Gehalt analysiert. Die Ergebnisse zeigen, dass die Bohne adäquat ist für menschliche Ernährung in diesen Nährstoffen, aber das die Trypsin hemmende Aktivität sollte vor dem Verzehrt zerstört.

Experimental and theoretical comparison of the precision of flame atomic absorption, fluorescence, and emission measurements

Theoretical equations and experimental evaluation procedures for the determination of the precision of flame atomic absorption, emission, and fluorescence measurements are presented. These procedures and noise power spectra are used to evaluate the precision and noise characteristics of atomic copper measurements with all three techniques under the same experimental conditions in an H2-air flame. At the detection limit, emission and fluorescence measurements are limited by background emission shot and flicker noise whereas absorption measurements are limited by flame transmission lamp flicker noise. Analyte flicker noise limits precision at higher analyte concentrations for all three techniques. Fluctutations in self-absorption and the inner filter effect are shown to contribute to the noise in atomic emission and fluorescence measurements.

Optimization of Precision and Accuracy in X-Ray Fluorescence Analysis of Silicate Rocks

The precision of XRF measurements on a Rigaku 3064 has been determined for 10 major and 12 trace elements in 10 geochemical reference rocks. A complete procedure for evaluating the sources of imprecision in XRF analyses is presented with new equations and data demonstrating that for many measurements a minute is an adequate count time for obtaining the minimum error (1% RSD) in an analysis. Longer analysis times were found to be limited by sample preparation errors, and for very long analysis times, the precision is predicted to get worse.

Optimization of instrumental variables in flame atomic absorption spectrometry

Abstract The optimization of flame atomic absorption instrumental variables such as hollow-cathode lamp current, slit width, slit height, flame type and stoichiometry, burner position, resonance line, and integration time for best precision or signal-to-noise ratio is discussed. Because different types of noise are limiting in different absorbance regions, optimum values of instrumental variables can vary with the absorbance measured.

Mountain Pine Beetle Attack Associated with Low Levels of 4-Allylanisole in Ponderosa Pine

Abstract Mountain pine beetle (Dendroctonus ponderosae) is the most important insect pest in southern Rocky Mountain ponderosa pine (Pinus ponderosa) forests. Tree mortality is hastened by the various fungal pathogens that are symbiotic with the beetles. The phenylpropanoid 4-allylanisole is an antifungal and semiochemical for some pine beetle species. We analyzed 4-allylanisole and monoterpene profiles in the xylem oleoresin from a total of 107 trees at six sites from two chemotypes of ponderosa pine found in Colorado and New Mexico using gas chromatography-mass spectroscopy (GC-MS). Although monoterpene profiles were essentially the same in attacked and nonattacked trees, significantly lower levels of 4-allylanisole were found in attacked trees compared with trees that showed no evidence of attack for both chemotypes.

Lead, Arsenic, and Cadmium Contamination and Its Impact on Children's Health in La Oroya, Peru

The large scale of nonferrous metal smelting has created a chronic public health issue in La Oroya, Peru. In this reconnaissance study, the distributions of lead, arsenic, and cadmium in drinking water, indoor dust, and soil were measured at five sites to estimate their impact on childrens health. As expected, median soil metal levels dropped exponentially with distance from the smelting complex (3,177 ppm Pb, 1,658 ppm As, and 127 ppm Cd at La Oroya Antigua). Indoor dust metal concentrations were also elevated at La Oroya Antigua (2,574 ppm Pb, 1,071 ppm As, 28 ppm Cd), and drinking water As values were elevated relative to Pb and Cd (8.5 ppb As, 0.28 ppb Pb, and 0.05 ppb Cd), suggesting selective loss of Pb and Cd relative to As. Exposure and dose-response modeling (IEUBK) indicate soil Pb and As are serious health problems in need of remediation.

Evaluation of the efficacy of spatiotemporal Pb isoscapes for provenancing of human remains

Geospatially distributed isotopes (isoscapes) from biogeochemically fractionated processes have been applied in many forensic investigations, such as authentication of food and sourcing of drugs. Provenancing of human remains using isotopes has been hindered by a lack of appropriate isoscapes, by changes in these isoscapes over time, and by various homogenization processes. In this study we create spatiotemporal isoscapes for anthropogenic lead (Pb) for the contiguous United States and Europe using literature data from dated sediments, soils and biological tissues. We compare (206)Pb/(207)Pb isoscapes with isoscapes of δ(13)C, δ(18)O and (87)Sr/(86)Sr to determine their relative efficacy for the forensic identification of human remains. We do this comparison using third molar enamel data from 22 United States Air Force Academy cadets with known life trajectories born between 1983 and 1985. We use these spatiotemporal isoscapes with osteologic analyses, hospital records and isotopic analyses of tooth enamel carbonate from permanent teeth to help identify 32 individuals from unmarked graves found in a forgotten 19th century mental asylum cemetery.

Nutritional evaluation of tepary bean: Elemental analysis of seed

Abstract Tepary bean (Phaseolus acutifolius var. latifolius), a potential arid‐land legume crop, was analyzed for total protein, oil, fiber and mineral content. Results indicate the bean would be adequate in these nutrients for a human diet if deficient amino acids in the seed‐protein were complimented.

Critical comparison of X-ray fluorescence and combustion-infrared methods for the determination of sulphur in biological matrices

Eleven NBS SRMs were used to evaluate XRF and combustion-IR as methods for the rapid, routine determination of sulphur and biological matrices. Relative standard deviations of 2.8 and 3.8% and analysis times of 1 and 3 min were obtained for the two methods, respectively, on dry, powdered material. Good agreement with the literature was obtained for plant tissues, but both methods produced higher results (14%) on animal tissues compared with NBS values.

Atomic Absorption for the Archaeologist: An Application to Pottery from Pella of the Decapolis

Abstract Atomic absorption spectrophotometry is a suitable, though presently little-recognized, method by which the archaeologist can obtain potentially relevant data on the elemental composition of artifacts. Its relatively low cost and the ease with which a minimally-trained technician can carry out the procedure make it particularly attractive as a routine archaeological procedure. By way of illustration the authors analyze a corpus of pottery from Pella and discuss the archaeological interpretation of the data.