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104 result(s) for "Sims, Douglas"
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Metal(loid)s Profile of Four Traditional Ethiopian Teff Brands: Geographic Origin Discrimination
Among the most renowned Ethiopian food crops, teff (Eragrostis tef (Zucc.)Trotter) is the most nutritious and gluten-free cereal. Because of the increase in demand for teff, it is necessary to establish geographic origin authentication of traditional teff brands based on multi-element fingerprint. For this purpose, a total of 60 teff samples were analysed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Accuracy of the laboratory procedure was verified by the analysis of rice flour standard reference material (NIST SRM 1568b). In this context, four traditional teff brands (Ada’a, Ginchi, Gojam and Tulu Bolo) were analytically characterized using multi-element fingerprint and further treated statistically using linear discriminant analysis (LDA). Due to obvious extrinsic Fe, Al and V contamination, these elements were excluded from the discriminant model. Five elements (Cu, Mo, Se, Sr, and Zn) significantly contributed to discriminate the geographical origin of white teff. On the other hand, Mn, Mo, Se and Sr were used as discriminant variables for brown teff. LDA revealed 90 and 100% correct classifications for white and brown teff, respectively. Overall, multi-element fingerprint coupled with LDA can be considered a suitable tool for geographic origin discrimination of traditional teff brands.
United States Grown and Imported Rice on Sale in Las Vegas: Metal(loid)s Composition and Geographic Origin Discrimination
Concentrations of metal(loid)s, Ag, Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Se, Sr, V and Zn, were determined in rice on sale in Las Vegas. The rice samples were grown in five different countries, the USA, Thailand, India, Pakistan, and Bangladesh. The elemental concentrations in rice grain were determined using inductively coupled plasma mass spectrometry (ICP-MS) following hot block-assisted digestion. The accuracy of the laboratory procedure was verified by the analysis of rice flour standard reference material (NIST SRM 1568b). The mean metal(loid) contents in rice of various geographic origins were 3.18–5.91 mg kg−1 for Al, 0.05–0.12 mg kg−1 for As, 3.64–41 μg kg−1 for Cd, 5.11–12 μg kg−1 for Co, 0.12–0.14 mg kg−1 for Cr, 1.5–1.91 mg kg−1 for Cu, 3.04–4.98 mg kg−1 for Fe, 4.2–10.4 mg kg−1 for Mn, 0.21–0.41 mg kg−1 for Ni, 0.02–0.07 mg kg−1 for Se, 0.68–0.88 mg kg−1 for Sr, 3.64–5.26 μg kg−1 for V, and 16.6–19.9 mg kg−1 for Zn. respectively. The mean concentration of As in US rice was significantly higher than in Indian, Pakistani, and Bangladeshi rice. On the other hand, it was found a significantly low mean level of Cd in US-grown rice. It was also found that the concentrations of metal(loid)s in black and brown rice on sale in Las Vegas were statistically similar, except for Mn and Se. The geographic origin traceability of rice grain involved the use of ICP-MS analysis coupled with chemometrics that allowed their differentiation based on the rice metal(loid) profile, thus confirming their origins. Data were processed by linear discriminant analysis, and US and Thai rice samples were cross-validated with higher accuracy (100%). This authentication quickly discriminates US rice from the other regions and adds verifiable food safety measures for consumers.
Assessment of environmental pollution and human health risks of mine tailings in soil: after dam failure of the Córrego do Feijão Mine (in Brumadinho, Brazil)
The dam failure of the Córrego do Feijão Mine (CFM) located in Minas Gerais State, Brazil, killed at least 278 people. In addition, large extensions of aquatic and terrestrial ecosystems were destroyed, directly compromising the environmental and socioeconomic quality of the region. This study assessed the pollution and human health risks of soils impacted by the tailing spill of the CFM dam, along a sample perimeter of approximately 200 km. Based on potential ecological risk and pollution load indices, the enrichments of Cd, As, Hg, Cu, Pb and Ni in soils indicated that the Brumadinho, Mário Campos, Betim and São Joaquim de Bicas municipalities were the most affected areas by the broken dam. Restorative and reparative actions must be urgently carried out in these areas. For all contaminated areas, the children’s group indicated an exacerbated propensity to the development of carcinogenic and non-carcinogenic diseases, mainly through the ingestion pathway. Toxicological risk assessments, including acute, chronic and genotoxic effects, on people living and working in mining areas should be a priority for public management and mining companies to ensure effective environmental measures that do not harm human health and well-being over time.
Uptake of Trace Elements in Leaves of the Larrea Tridentata (DC.) Coville in Desert Washes of an Arid Environment
Trace elements (As, Cd, Cr, Pb, Ba, Fe, Al, Mn and Ba) were uptaken by the leaves of the creosote bush (Larrea tridentata (DC.) Coville) in Nelson, Nevada, although at low concentrations. Samples were collected up-gradient of the mine tailings, the tailings, and down gradient from the source to measure spatial distribution. Data show that trace elements (As, Ba, Cr, Hg, Se) enter L. tridentata through root tissues, migrating to leaf tissue, but at significantly lower levels than that of the source sediments. Metalloid (As and Se) concentrations in the leaf tissues ranged from non-detect to greater than 44 mg kg−1 As and non-detect to over 34 mg kg−1 Se. For trace metals, Hg ranged from non-detect to 0.14 mg kg−1; Ba from 1.74 to 4.12 mg kg−1; and Cr from non-detect to 6.18 mg kg−1 while Ag, Cd, and Pb were not detected in the plant leaves. When comparing the ratio of sediment metal concentration to plant metal concentrations, the Techatticup Wash contained the highest levels of trace elements in the leaves of the L. tridentata, followed by the Carnation Wash, with the Eagle Wash containing the lowest concentrations of trace elements.
Enhancing Resilience in an Operational Unit
Resilient soldiers, cohesive teams, and adaptable leaders serve as the backbone of the human dimensions concept, enabling effective performance in decentralized operations over protracted periods of conflict. While there are many ways to build these capabilities, including tough realistic training, soldiers can also be trained in specific resilience skills that help them withstand and recover from significant stress. Such training can yield surprising benefits; but with competing requirements for units’ time, leaders want to be confident that resilience training is worth the effort. While evidence-based resilience training that has proven effective with service members is a wise investment, both financially and in terms of human resources, even good, empirically validated resilience training implemented half-heartedly and with mixed messages from leadership is not worthwhile. When the unit environment undermines the purpose of resilience training with a “check-the-block” mentality or when the training is isolated from everyday military life, the training loses potential value. And, despite its potential importance in helping soldiers, resilience training is not a panacea: everyone has a point at which bouncing back from stress is more difficult.
Incorporating Oxygen-Enhanced MRI into Multi-Parametric Assessment of Human Prostate Cancer
Hypoxia is associated with prostate tumor aggressiveness, local recurrence, and biochemical failure. Magnetic resonance imaging (MRI) offers insight into tumor pathophysiology and recent reports have related transverse relaxation rate (R2*) and longitudinal relaxation rate (R1) measurements to tumor hypoxia. We have investigated the inclusion of oxygen-enhanced MRI for multi-parametric evaluation of tumor malignancy. Multi-parametric MRI sequences at 3 Tesla were evaluated in 10 patients to investigate hypoxia in prostate cancer prior to radical prostatectomy. Blood oxygen level dependent (BOLD), tissue oxygen level dependent (TOLD), dynamic contrast enhanced (DCE), and diffusion weighted imaging MRI were intercorrelated and compared with the Gleason score. The apparent diffusion coefficient (ADC) was significantly lower in tumor than normal prostate. Baseline R2* (BOLD-contrast) was significantly higher in tumor than normal prostate. Upon the oxygen breathing challenge, R2* decreased significantly in the tumor tissue, suggesting improved vascular oxygenation, however changes in R1 were minimal. R2* of contralateral normal prostate decreased in most cases upon oxygen challenge, although the differences were not significant. Moderate correlation was found between ADC and Gleason score. ADC and R2* were correlated and trends were found between Gleason score and R2*, as well as maximum-intensity-projection and area-under-the-curve calculated from DCE. Tumor ADC and R2* have been associated with tumor hypoxia, and thus the correlations are of particular interest. A multi-parametric approach including oxygen-enhanced MRI is feasible and promises further insights into the pathophysiological information of tumor microenvironment.
Buellia dispersa (Lichens) Used as Bio-Indicators for Air Pollution Transport: A Case Study within the Las Vegas Valley, Nevada (USA)
Hazardous substances (e.g., toxic elements, oxides of nitrogen, carbon and sulfur) are discharged to the environment by a number of natural and anthropogenic activities. Anthropogenic air pollution commonly contains trace elements derived from contaminants and additives released into the atmosphere during fossil fuel combustion (automobiles, power generation, etc.) as well as physical processes (e.g., metal refining, vehicle brake wear, and tire and pavement wear). Analysis of pollutant chemical concentrations in lichens collected across the Las Vegas Valley allows documentation of the distribution of air pollution in the Valley. Analyses of lichen biomass (Buellia dispersa), when compared to windrose diagrams, shows pathways of airborne pollutant transport across the Las Vegas Valley. The west and north sectors of the Las Vegas Valley contained the lowest target contaminates (e.g., Cr, Cu, Co, Pb, Ni) and the highest NO3− while the east and south sectors contained the highest levels of target contaminates and lowest NO3−. Additionally, metals and NO3− detected in the east and south sectors of the valley indicate that air pollution generated in the valley is moving from the south to the north-northeast and across the valley, exiting on the north and south side of Frenchman Mountain.
Trace Element Scavenging in Dry Wash Surficial Sediments in an Arid Region of Southern Nevada, USA
Sediment samples were collected from a dry wash in Nelson, Nevada where the Techatticup Mine and Mill operated between 1850 and 1960. Samples were used to evaluate movement and behavior of certain metals and metalloids including aluminum, arsenic, barium, cadmium, copper, iron, manganese, lead, and vanadium. The data show that some metals and metalloids are more concentrated on larger particles whereas others show the opposite tendency. For example, As was greatest on silt fractions and least on coarse fractions, while Se was detected only on silts. Chromium, Cu, Fe, Mn, Pb, and Zn concentrations all increased with decreasing particle size (silt > sand > coarse), whereas Al, Ba, and V showed the opposite trend (silt < sands < coarse).
Risk of Metal Mobilization from Redevelopment Activities in Hyperarid Climates: A Laboratory Experiment and Discussion
The reclamation and redevelopment of abandoned mine sites into parks, golf courses, and residential communities in arid and hyperarid regions has been caused, in part, to rising land costs. A laboratory experiment using three columns was monitored for 273 days to evaluate trace metal and metalloid availability. The sediment from the Three Kids Mine that was used in this study is documented to contain high levels of trace metals and metalloids. The experiment simulated agricultural activities over time to assess whether fertilizers would mobilize trapped contaminants. Results indicate that irrigation and fertilizers can provide conditions for Pb, Mn, Zn, Al, Ba, Cu, and As to become mobile, though on a limited basis. There was an increase in Pb, Mn, Zn, Al, Ba, Cu, and As within the first 30 days followed by a decrease at 90 days. Concentrations of Pb, Mn, and Zn increased at 273 days due to application of fertilizer-fortified waters. This study shows the potential for mobilized trace metals and metalloids to enter the wider environment after developmental activities are finished.
Mentorship: Sparking a sense of wonder
According to the United States Geological Survey, nearly 85% of the country's drinking water originates from surface waters such as rivers and lakes. [...]research offers a great amie environment to learn, teach and share and a continuous process in life with no end. Teaching students' strengths helps them develop confidence in their own abilities and empowers them to perform better, all while establishing a STEM mindset. [...]every learning experience is an opportunity for assessing a student's own growth. [...]teaching a student that a good scientist does tasks, but a great scientist takes risks is the most rewarding thing a scientist can do in their career.