Cultural identity central to Native American persistence in science.

Native Americans are the least represented population in science fields. In recent years, undergraduate and graduate level summer research programs that aimed to increase the number of Native Americans in science have made some progress. As new programs are designed, key characteristics that address science self-efficacy and science identity and provide supports for Native American students' commitment to a scientific career should be considered. In this study, we used sequential mixed methods to investigate the potential of culturally tailored internship programs on Native American persistence in science. We analyzed surveys (n = 47) and interviews (n = 4) with Native American students to understand their perceptions of themselves in relation to science research and how summer research experiences might develop science identities. Based on regression modeling, science identity, but not science self-efficacy, predicted intent to persist in science. In turn, science self-efficacy and Native American identity predicted science identity, and this suggests cultural identity is central to Native American persistence in science. In interviews, students' comments reinforced these findings and shed light on students' reasoning about the kinds of science experiences they sought; specifically, they chose to participate in culturally tailored internships because these programs provided a sense of belonging to the scientific community that did not conflict with their cultural identities. Based on our analysis, we propose an Indigenous science internship model and recommend that agencies target funding for culturally tailored programs from high school through early-investigator levels as well as provide inclusive programmatic and mentoring guidelines.

Determination of arsenobetaine in fish tissue by species specific isotope dilution LC-LTQ-Orbitrap-MS and standard addition LC-ICPMS.

An accurate and precise method for the determination of arsenobetaine (AsB, (CH(3))(3)(+)AsCH(2)COO(-)) in fish samples using exact matching species specific isotope dilution (ID) liquid chromatography LTQ-Orbitrap mass spectrometry (LC-LTQ-Orbitrap-MS) and standard addition LC inductively coupled plasma mass spectrometry (LC-ICPMS) is described. Samples were extracted by sonication for 30 min with high purity deionized water. An in-house synthesized (13)C enriched AsB spike was used for species specific ID analysis whereas natural abundance AsB, synthesized and characterized by quantitative (1)H NMR (nuclear magnetic resonance spectroscopy), was used for reverse ID and standard addition LC-ICPMS. With the LTQ-Orbitrap-MS instrument in scan mode (m/z 170-190) and resolution set at 7500, the intensities of [M + H](+) ions at m/z of 179.0053 and 180.0087 were used to calculate the 179.0053/180.0087 ion ratio for quantification of AsB in fish tissues. To circumvent potential difficulty in mass bias correction, an exact matching approach was applied. A quantitatively prepared mixture of the natural abundance AsB standard and the enriched spike to give a ratio near one was used for mass bias correction. Concentrations of 9.65 ± 0.24 and 11.39 ± 0.39 mg kg(-1) (expanded uncertainty, k = 2) for AsB in two fish samples of fish1 and fish2, respectively, were obtained by ID LC-LTQ-Orbitrap-MS. These results are in good agreement with those obtained by standard addition LC-ICPMS, 9.56 ± 0.32 and 11.26 ± 0.44 mg kg(-1) (expanded uncertainty, k = 2), respectively. Fish CRM DORM-2 was used for method validation and measured results of 37.9 ± 1.8 and 38.7 ± 0.66 mg kg(-1) (expanded uncertainty, k = 2) for AsB obtained by standard addition LC-ICPMS and ID LC-LTQ-Orbitrap-MS, respectively, are in good agreement with the certified value of 39.0 ± 2.6 mg kg(-1) (expanded uncertainty, k = 2). Detection limits of 0.011 and 0.033 mg kg(-1) for AsB with LC-ICPMS and ID LC-LTQ-Orbitrap-MS, respectively, were obtained demonstrating that the technique is well suited to the determination AsB in fish samples. To the best of our knowledge, this is first application of species specific isotope dilution for the accurate and precise determination of AsB in biological tissues.

Lessons From the First Decade of the Native American Summer Research Internship at the University of Utah.

PROBLEM: American Indian/Alaska Native (AI/AN) populations are facing multiple health crises, including limited access to care, high rates of chronic disease, and early mortality that is far worse than other underrepresented minorities in the United States. According to the Association of American Indian Physicians, AI/AN people represent 2.0% of the U.S. population but only 0.2% of medical students and 0.1% of full-time faculty at MD-granting institutions. Increasing the number of AI/AN clinicians and scientists is one strategy to improve health outcomes in the AI/AN population and address these crises. APPROACH: In 2010, the University of Utah partnered with research, cultural, and professional mentors to create a 10-week summer Native American Research Internship (NARI) program for AI/AN college students across the United States who are interested in pursuing biomedical careers. NARI attracts and supports AI/AN students by offering mentored summer research internships in an innovative, culturally aware framework that adapts to observed challenges to optimize educational experiences and support biomedical career aspirations. OUTCOMES: During the first decade of the NARI program, 128 students from 22 U.S. states, representing 46 tribal nations and 57 colleges and universities, participated. Of those 128 students, 113 (88%) have completed a bachelor's degree and the remaining 15 (12%) are currently working toward a bachelor's degree. No NARI student has dropped out of college. Twenty-six (20%) NARI alumni have matriculated to medical school and 30 (23%) to graduate school. Eight (6%) participants have completed medical school, and 3 (2%) are pursuing a PhD in science. An additional 36 (28%) have gained employment in biomedical research fields. NEXT STEPS: The NARI program has increased the participation of AI/AN students in medicine and the biomedical sciences. The innovative, culturally aware, and adaptive framework is a model for other programs for AI/AN students and students in other underrepresented communities.

Mercury in arctic air: the long-term trend.

The long-term (1974-2000) time trend of total filterable mercury (TFM) in the air in the Canadian Arctic is reported. The concentration of TFM had declined by (3.0+/-0.8) % and (3.1+/-0.9) % per year in the summer and fall, respectively, over the 27 years, which coincided with the calculated reduction rate of world-wide mercury emission (~3.3% per year) from human activities between 1983 and 1995. The time trend for winter and early spring was not statistically significant as the variability of TFM was very large, partly due to Arctic Mercury Depletion Events and partly due to Arctic haze.

Total filterable mercury and 210Pb in the Canadian Arctic air.

Total filterable mercury (TFM) and lead-210 ((210)Pb) were measured for a one-year air particulate sample series collected weekly at Resolute (74.7 degrees N, 95.0 degrees W), a Canadian high Arctic site, during July 1999 and June 2000. The measurements showed a clear time lag of two months between the peak concentrations of TFM and (210)Pb.

Causes and costs for ED visits after pediatric adenotonsillectomy.

OBJECTIVE: (1) Review the reasons, timing, and costs for children presenting to the emergency department (ED) after adenotonsillectomy (T&A). STUDY DESIGN: Case series with chart review. SETTING: Tertiary care children's hospital. SUBJECTS AND METHODS: A standardized activity-based hospital accounting system was used to identify 437 children from an academic pediatric otolaryngology practice presenting to the ED after T&A from 2009 to 2012. The reason for presentation, timing after surgery, and facility costs were recorded. RESULTS: The study cohort represented 13.3% of the 3198 patients who underwent T&A during that time period. Overall, 133 (4.2%) presented for dehydration, 106 (3.3%) presented for post-tonsillectomy hemorrhage, 65 (2.0%) for poorly controlled pain, 42 (1.3%) for fever, 29 (1.0%) for vomiting/nausea/GI discomfort, 22 (0.7%) for respiratory complications, and 12 (0.4%) for miscellaneous reasons related to the operation; 28 (0.8%) were unrelated to the T&A and excluded. Mean postoperative day at the time of ED presentation was 4.4 (95% CI, 4.1-4.7). The mean cost per patient presenting to the ED was $1420 (95% CI, $1104-$1737), the most costly subgroups being those presenting with respiratory complications ($2855; 95% CI, $1434-$4277), hemorrhage ($1502; 95% CI, $1216-$1787), and dehydration ($1372; 95% CI, $995-$1750). The least costly subgroup was acute postoperative pain ($781; 95% CI, $282-$1200). CONCLUSION: A significant portion of children present to the ED after T&A for poorly controlled pain, dehydration, or fever. The costs from these visits are significant. Accounting for these costs in the global care for pediatric T&A could assist in calculating appropriate reimbursement for bundled payments in this climate of health care reform.

Ultrasound-assisted vapor generation of mercury.

Cold vapor generation arising from reduction of both Hg(2+) and CH(3)Hg(+) occurs using ultrasonic (US) fields of sufficient density to achieve both localized heating as well as radical-based attack in solutions of formic and acetic acids and tetramethylammonium hydroxide (TMAH). A batch sonoreactor utilizing an ultrasonic probe as an energy source and a flow through system based on a US bath were optimized for this purpose. Reduction of CH(3)Hg(+) to Hg(0) occurs only at relatively high US field density (>10 W cm(-3) of sample solution) and is thus not observed when a conventional US bath is used for cold vapor generation. Speciation of mercury is thus possible by altering the power density during the measurement process. Thermal reduction of Hg(2+) is efficient in formic acid and TMAH at 70 degrees C and occurs in the absence of the US field. Room temperature studies with the batch sonoreactor reveal a slow reduction process, producing temporally broad signals having an efficiency of approximately 68% of that arising from use of a conventional SnCl(2) reduction system. Molecular species of mercury are generated at high concentrations of formic and acetic acid. Factors affecting the generation of Hg(0) were optimized and the batch sonoreactor used for the determination of total mercury in SLRS-4 river water reference material.

Characterization of a suite of ginkgo-containing standard reference materials.

A suite of three ginkgo-containing dietary supplement Standard Reference Materials (SRMs) has been issued by the National Institute of Standards and Technology (NIST) with certified values for flavonoid aglycones, ginkgolides, bilobalide, and selected toxic trace elements. The materials represent a range of matrices (i.e., plant, extract, and finished product) that provide different analytical challenges. The constituents have been determined by at least two independent analytical methods with measurements performed by NIST and at least one collaborating laboratory. The methods utilized different extractions, chromatographic separations, modes of detection, and approaches to quantitation. The SRMs are primarily intended for method validation and for use as control materials to support the analysis of dietary supplements and related botanical materials.

Determination of total mercury in biological samples using flow injection CVAAS following tissue solubilization in formic acid.

Total mercury in biological samples was determined by flow injection (FI) cold vapour atomic absorption spectrometry (CVAAS) following tissue solubilization with formic acid. A mixture of potassium bromide and potassium bromate was used to decompose organomercury compounds prior to their reduction with sodium borohydride. A gold amalgam system was used to achieve lower detection limits when required. National Research Council Canada certified reference materials dogfish liver (DOLT-3), dogfish flesh (DORM-2) and lobster hepatopancreas (TORT-2), as well as oyster tissue (NIST SRM 1566b) and mussel tissue (NIST SRM 2976) were used to assess the accuracy of the method. The method of standard additions provided the most accurate results. Limit of detection (LOD) for Hg in the solid sample of 0.001 and 0.01mugg(-1) were achieved with and without amalgamation, respectively. The precision of measurement for 1.6ngml(-1) methylmercury was 2.7% using the amalgam system.

Certification of a new selenized yeast reference material (SELM-1) for methionine, selenomethinone and total selenium content and its use in an intercomparison exercise for quantifying these analytes.

A new selenized yeast reference material (SELM-1) produced by the Institute for National Measurement Standards, National Research Council of Canada (INMS, NRC) certified for total selenium (2,059+/-64 mg kg(-1)), methionine (Met, 5,758+/-277 mg kg(-1)) and selenomethionine (SeMet, 3,431+/-157 mg kg(-1)) content is described. The +/-value represents an expanded uncertainty with a coverage factor of 2. SeMet and Met amount contents were established following a methanesulfonic acid digestion of the yeast using GC-MS and LC-MS quantitation. Isotope dilution (ID) calibration was used for both compounds, using 13C-labelled SeMet and Met. Total Se was determined after complete microwave acid digestion based on ID ICP-MS using a 82Se spike or ICP-OES spectrometry using external calibration. An international intercomparison exercise was piloted by NRC to assess the state-of-the-art of measurement of selenomethione in SELM-1. Determination of total Se and methionine was also attempted. Seven laboratories submitted results (2 National Metrology Institutes (NMIs) and 5 university/government laboratories). For SeMet, ten independent mean values were generated. Various acid digestion and enzymatic procedures followed by LC ICP-MS, LC AFS or GC-MS quantitation were used. Four values were based on species-specific ID calibration, one on non-species-specific ID with the remainder using standard addition (SA) or external calibration (EC). For total selenium, laboratories employed various acid digestion procedures followed by ICP-MS, AFS or GC-MS quantitation. Four laboratories employed ID calibration, the remaining used SA or EC. A total of seven independent results were submitted. Results for methionine were reported by only three laboratories, all of which used various acid digestion protocols combined with determination by GC-MS and LC UV. The majority of participants submitted values within the certified range for SeMet and total Se, whereas the intercomparison was judged unsuccessful for Met because only two external laboratories provided values, both of which were outside the certified range.

Determination of thorium and uranium in ultrapure lead by inductively coupled plasma mass spectrometry.

A method for the determination of U and Th at sub-ppt levels in high-purity Pb samples using extraction chromatography with ICPMS detection is described. Following acid digestion, uranium and thorium are separated from the lead matrix using UTEVA resin. Sorption and elution procedures were optimized, the potential reusability of the chromatographic resin was evaluated, and a performance comparison between prepacked and freshly prepared UTEVA column was made. Uranium could be eluted with 0.025 M HCl and Th then recovered using 0.5% oxalic acid. Recovery yields for U exceed 80% whereas those for Th were typically 60%. Procedural detection limits of 0.5 and 1.5 pg g(-)(1) were obtained for U and Th, respectively. For purposes of comparison, GD-MS analysis of samples was also performed, yielding results consistent with those generated by ICPMS but with inferior detection power.

Formic acid solubilization of marine biological tissues for multi-element determination by ETAAS and ICP-AES.

A simple, fast method is described for the determination of Ag, As, Cd, Cu, Cr, Fe, Ni, and Se in marine biological tissues by electrothermal atomic-absorption spectrometry (ETAAS) and Na, Ca, K, Mg, Fe, Cu, and Mn by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Solubilization of the biological tissue was achieved by using formic acid with vortex mixing followed by heating to 50 degrees C in an ultrasonic bath. Once solubilized, the tissues were diluted to an appropriate volume with water for analysis. Aliquots were sampled into a graphite furnace and ICP-AES using a conventional autosampler. The method was validated by use of biological certified reference materials from NRC, DORM-2, DOLT-2, DOLT-3, LUTS-1, TORT-2, and NIST SRMs 1566b and 2976. Simplicity and reduced sample-preparation time prove to be the major advantages to the technique.

Preparation and certification of a reference material for the determination of nutrients in seawater.

There is an urgent need for natural water reference materials certified for nutrients. In 1996, NRC collected seawater for a proposed CRM at a depth of 200 m in the North Atlantic; this was immediately filtered through 0.05-microm cartridge filters into 50-L carboys. The water was later homogenized in the NRC laboratories in Ottawa and stabilized via gamma irradiation. Over six years of stability testing no significant deterioration was detected. In addition to the usual customary standard colorimetric procedures, alternative analytical methods were developed to enable the certification process. The production of a CRM called MOOS-1 will be discussed. Certified values, with uncertainty components addressing the homogeneity, stability, and characterization of the material, were calculated to be: orthophosphate=1.56+/-0.07 micro mol L(-1), silicate=26.0+/-1.0 micro mol L(-1), nitrite=3.06+/-0.15 micro mol L(-1), and nitrite and nitrate=23.7+/-0.9 micro mol L(-1).

Effects of gamma-sterilization on butyltin homogeneity and content in sediments: a GC-ICP-MS study.

A GC-ICP-MS method based on extraction and alkylation of butyltins with sodium tetraethylborate was used to quantitatively assess the fate of these analytes in solutions and sediments following exposure to gamma-irradiation. The effects of a 2.5 Mrad sterilization dose on three butyltin species in both methanolic calibration solutions and in sediment matrices were investigated. Although significant losses of tributyltin (TBT, 90%), dibutyltin (DBT, 100%) and monobutyltin (MBT, 80%) were detected in standard solutions prepared in methanol following gamma-irradiation, no species inter-conversion occurred. Some degradation of TBT (38%) and DBT (32%) but no significant change in MBT content was found using a spiked sediment CRM HISS-1. Conversion DBT to MBT in spiked HISS-1 was deduced. Much smaller degradation of TBT (16% loss) and 10% loss of DBT by conversion to MBT (14% gain) was registered using a sediment blend of PACS-2 and HISS-1 (SOPH). Despite some initial losses of TBT and DBT due to irradiation, better than 2% RSD in both TBT and DBT concentrations measured in twelve different bottles of blended sediment SOPH were obtained, indicating the material may be considered homogeneous for these analytes. Results from a long-term five-year stability study of PACS-2 show that all three butyltins are stable during storage at 4 degrees C followed with 2.5 Mrad minimum dose of gamma-irradiation sterilization treatment.