Using Kern's Model to Redesign a Postgraduate Curriculum for Orthopaedic Physician Assistants.

ABSTRACT: Postgraduate physician assistant (PA) specialty training expands entry-level education, allowing PAs to work in concentrated fields. The United States Army - Baylor University Doctor of Science in PA Studies Orthopaedics program provides formal education to fill the capability gap caused by surgeon shortages in the military. Based on several sources of feedback, the authors recognized that the curriculum needed modernization and set forth to rewrite the curriculum. This article describes the use of Kern's 6-Step Approach for Curriculum Development for Medical Education to redesign a curriculum for an 18-month postgraduate doctoral program for military orthopaedic PAs. The resulting formal curriculum enables 4 geographically separated sites to execute an orthopaedic PA degree program that addresses a critical specialty care access challenge for the military. Kern's 6-Step approach could be used to design or redesign any PA educational content, from a single course to an entire degree program.

Care at Your Fingertips: Codesign, Development, and Evaluation of the Oncology Hub App for Remote Symptom Management in Pediatric Oncology.

PURPOSE: To codesign, develop, and evaluate a smartphone app that includes patient-reported measures of symptoms and real-time advice in children's cancer. METHODS: The Oncology Hub is a comprehensive approach to symptom management that includes a suite of codesigned tools and resources including clinical algorithms to determine the level of concern, symptom management advice, and resources for families of children with cancer. The evaluation involved Think Aloud interviews with parent and adolescent patients to complete tasks in the app as well as a User Experience questionnaire (score range, 0-120) and qualitative feedback. The accuracy of algorithms was determined by repeated testing of inputs and outputs over 4 weeks. RESULTS: Design and wireframes were iteratively refined through consultation with parents and adolescents confirming the final design. Beta testing evaluation was then completed by 25 participants including two adolescents. Across all participants, 84% of tasks were easy to navigate, and the Oncology Hub demonstrated high usability, usefulness, and acceptability with participants' scores ranging between 90 and 120 (mean = 112.2, standard deviation = 9.43). Qualitative feedback was positive. Testing of algorithms identified inconsistencies in understanding between clinical research and coding teams; refinements were made until the expected response notifications were returned with 100% accuracy. CONCLUSION: Technology offers new ways to think about how clinicians and families communicate and share information to harness the best of community and hospital services. Understanding how information is exchanged using health apps, and how this affects clinical workflow is critical to successful implementation, and optimizing symptom assessment and management in children with cancer.

The Role of Pandemic Fatigue in Seeking and Avoiding Information on COVID-19 Among Young Adults.

The health information environment surrounding COVID-19 is complex, with varying and competing information. This study uses the risk information seeking and processing model (RISP) to examine COVID-19 information seeking and avoiding among young adults. Pandemic fatigue is also operationalized and tested as a more nuanced measure of negative affective response within the RISP framework. Survey results (N = 527) reveal pandemic fatigue predicts information seeking and avoidance, but may have a weaker influence on these outcome variables than the RISP's original construct of negative affective response. Additionally, the original RISP model achieved slightly more explanatory power in predicting risk information seeking than our revised RISP model, using pandemic fatigue as an alternative measure of negative affective response. These findings indicate that contemporary concepts such as pandemic fatigue may be incorporated into applications of the RISP model, thus allowing researchers to evaluate other types of negative affective responses to risk and further expanding the utility of the model. Theoretical implications and practical recommendations for public health officials and health care workers are discussed.

A platform for oncogenomic reporting and interpretation.

Manual interpretation of variants remains rate limiting in precision oncology. The increasing scale and complexity of molecular data generated from comprehensive sequencing of cancer samples requires advanced interpretative platforms as precision oncology expands beyond individual patients to entire populations. To address this unmet need, we introduce a Platform for Oncogenomic Reporting and Interpretation (PORI), comprising an analytic framework that facilitates the interpretation and reporting of somatic variants in cancer. PORI integrates reporting and graph knowledge base tools combined with support for manual curation at the reporting stage. PORI represents an open-source platform alternative to commercial reporting solutions suitable for comprehensive genomic data sets in precision oncology. We demonstrate the utility of PORI by matching 9,961 pan-cancer genome atlas tumours to the graph knowledge base, calculating therapeutically informative alterations, and making available reports describing select individual samples.

Journeys, Not Destinations: Theorizing a Process View of Supply Chain Integrity.

Integrity is considered an important corporate value. Yet recent global events have highlighted the challenges firms face at living up to their stated values, especially when extended supply chain partners are involved. The concept of Supply Chain Integrity (SCI) can help firms shift focus beyond internal corporate integrity, toward supply chain integrity. Researchers and managers will benefit from an understanding of the SCI concept toward implementing SCI to better align supply chain partners with stated corporate values. This research fully develops and empirically grounds the firm-level, inter-firm-oriented SCI concept. The thematic analysis of six firms' archival and website content elaborated empirical descriptions of SCI themes and enabled the development of a process model for SCI, presenting a novel view of the underlying process by which firms can assess, develop, and maintain SCI across their supply chains. We propose the SCI model as an evolutionary process to improve a firm's supply chain sustainability, rather than a dichotomous end state where firms either "have" integrity or they don't. The SCI model could be used as a tool to help leaders create necessary change to better align values and supporting statements with culture, while influencing and affecting stakeholders across the supply chain. This is particularly important in today's world, where business leaders must consider all stakeholders and address important stakeholder-driven issues such as supply chain sustainability, resilience, and security, which are now at the forefront in the ever-changing environment.

Evaluation of Alitretinoin for the Treatment of Mycosis Fungoides and Sézary Syndrome.

BACKGROUND: Mycosis fungoides (MF) and Sézary syndrome (SS) are the most common subtypes of cutaneous T-cell lymphoma (CTCL). There is currently no cure for CTCL, and treatment is aimed at limiting disease progression. This study evaluated the efficacy and tolerability of alitretinoin in CTCL management. METHODS: A retrospective, multicenter study was conducted on CTCL patients treated with alitretinoin as a primary agent or in combination with standard therapies. RESULTS: Forty-eight patients with MF (n = 40) and SS (n = 8) with a median age of 59.7 years (±14.3) were eligible for study inclusion. Treatment response data were evaluated in 40 patients and safety in 42 patients. 40.0% of the patients had early-stage, 43.8% had advanced-stage CTCL, and in 16.7% of patients there was insufficient information for staging. 40.0% (16/40) of the patients achieved a complete or partial response, whereas 47.5% (19/40) achieved stable disease, 12.5% (5/40) had progressive disease, and there were no cases of disease relapses in responders. Both early and advanced stages of CTCL were responsive to alitretinoin as a primary or combined modality. Alitretinoin was well tolerated, and 64.3% (27/42) of patients did not report any side effects. The most commonly observed side effect was hypertriglyceridemia. CONCLUSIONS: This retrospective analysis supports the efficacy and safety of alitretinoin in clearing skin disease and preventing disease progression in CTCL as a monotherapy or in combination with standard therapies.

Association between Prurigo Nodularis and Etiologies of Peripheral Neuropathy: Suggesting a Role for Neural Dysregulation in Pathogenesis.

Background: Prurigo nodularis (PN) is an intensely pruritic skin condition of considerable morbidity. However, the pathogenesis of PN and its association with underlying neuropathy is unclear. Objective: We sought to investigate the association between PN and etiologies of peripheral neuropathy. Methods: A cross-sectional analysis of adult patients (≥18-year-old) with PN, AD, and Psoriasis at the Johns Hopkins Health System over a six-year period (January 2013-January 2019) was performed. The strength of association with etiologies of peripheral neuropathy were compared to a control cohort of individuals without PN, as well as those with AD or psoriasis. Results: A total of 1122 patients with PN were compared to 10,390 AD patients, 15,056 patients with psoriasis, and a control cohort of 4,949,017 individuals without PN, with respect to 25 comorbidities associated with peripheral neuropathies. Limitations: Comparisons between peripheral neuropathies and PN represent associations but are not causal relationships. Conclusion: Prurigo nodularis is strongly associated with peripheral neuropathies, suggesting a role for neural dysregulation in pathogenesis.

Risky business: Investigating influences on large truck drivers' safety attitudes and intentions.

INTRODUCTION: Safety research in the U.S. motor carrier context remains important, as the trucking industry employs approximately 1.7 million large truck drivers. Drivers face many competing pressures in this unique high risk, high regulation, and low direct supervision context. They represent the cornerstone of safe carrier operations. METHODS: Using a multi-theoretical approach, this study investigates how drivers' perceptions of carrier safety climate influence their safety-related attitudes and intentions. RESULTS: Responses from nearly 1500 over the road drivers provide evidence that safety climate directly influences drivers' attitudes toward safety, safety norms, and driver risk avoidance, and indirectly influences drivers' intentions to commit unsafe acts. These findings replicate previous findings and also extend the nomological network of theory in this context, adding driver risk avoidance as a central factor to the driver safety theoretical framework. Additionally, carrier managers are encouraged to reflect on the study's evidence and pursue a better understanding of their drivers' risk perceptions and tolerance, while minimizing avoidable risk through prudent safety and operational policies, procedures, and processes. Future research in this area is highly encouraged.

Comorbidities in Mycosis Fungoides and Racial Differences in Co-Existent Lymphomatoid Papulosis: A Cross-Sectional Study of 580 Patients in an Urban Tertiary Care Center.

Background: Mycosis fungoides (MF) is a cutaneous T-cell lymphoma. Previous reports have suggested MF is associated with inflammatory conditions such as psoriasis, increased cardiovascular risk factors as well as secondary neoplasms. Methods: A cross-sectional study of MF patients seen from 2013 to 2019 was performed. Comorbidities were selected based on the 2015 Medicare report highlighting the most common chronic medical illnesses in the United States. Lifetime comorbidity occurrence in patients with MF were compared with that in patients with atopic dermatitis, psoriasis and patients without MF. Additional analyses were performed with patients sub-stratified by race. Results: Compared to control groups, MF was strongly associated with lymphomatoid papulosis and Hodgkin's disease, but not significantly associated with lung, breast or colon cancer. Interestingly, the association with lymphomatoid papulosis was observed in Caucasians (CI 1062-4338; p < 0.001) and not African Americans (p = 0.9). Patients with MF had a greater association with congestive heart failure, hypertension (HT) and hyperlipidemia (HLD) compared with the general population. However, they were significantly less likely to have HT and HLD when compared with psoriasis patients (HT CI: 0.6-0.9; p < 0.001, and HLD CI: 0.05-0.07; p < 0.001). MF patients were also significantly less likely to have concomitant vitamin D deficiency compared with atopic dermatitis (AD) and psoriasis (p < 0.001). Conclusions: Our results suggest that the association of MF with lymphomatoid papulosis varies by race. Compared to the general population, hypertension and hyperlipidemia were positively associated with MF, however, these were significantly less likely on comparison to psoriasis. Unlike previously described, vitamin D deficiency was found to be significantly less in patients with MF.

Analysis of CTCL cell lines reveals important differences between mycosis fungoides/Sézary syndrome vs. HTLV-1+ leukemic cell lines.

HTLV-1 is estimated to affect ~20 million people worldwide and in ~5% of carriers it produces Adult T-Cell Leukemia/Lymphoma (ATLL), which can often masquerade and present with classic erythematous pruritic patches and plaques that are typically seen in Mycosis Fungoides (MF) and Sézary Syndrome (SS), the most recognized variants of Cutaneous T-Cell Lymphomas (CTCL). For many years the role of HTLV-1 in the pathogenesis of MF/SS has been hotly debated. In this study we analyzed CTCL vs. HTLV-1+ leukemic cells. We performed G-banding/spectral karyotyping, extensive gene expression analysis, TP53 sequencing in the 11 patient-derived HTLV-1+ (MJ and Hut102) vs. HTLV-1- (Myla, Mac2a, PB2B, HH, H9, Hut78, SZ4, Sez4 and SeAx) CTCL cell lines. We further tested drug sensitivities to commonly used CTCL therapies and studied the ability of these cells to produce subcutaneous xenograft tumors in NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ mice. Our work demonstrates that unlike classic advanced MF/SS cells that acquire many ongoing balanced and unbalanced chromosomal translocations, HTLV-1+ CTCL leukemia cells are diploid and exhibit only a minimal number of non-specific chromosomal alterations. Our results indicate that HTLV-1 virus is likely not involved in the pathogenesis of classic MF/SS since it drives a very different pathway of lymphomagenesis based on our findings in these cells. This study also provides for the first time a comprehensive characterization of the CTCL cells with respect to gene expression profiling, TP53 mutation status, ability to produce tumors in mice and response to commonly used therapies.

Drone Transport of Chemistry and Hematology Samples Over Long Distances.

OBJECTIVES: We addressed the stability of biological samples in prolonged drone flights by obtaining paired chemistry and hematology samples from 21 adult volunteers in a single phlebotomy event-84 samples total. METHODS: Half of the samples were held stationary, while the other samples were flown for 3 hours (258 km) in a custom active cooling box mounted on the drone. After the flight, 19 chemistry and hematology tests were performed. RESULTS: Seventeen analytes had small or no bias, but glucose and potassium in flown samples showed an 8% and 6.2% bias, respectively. The flown samples (mean, 24.8°C) were a mean of 2.5°C cooler than the stationary samples (mean, 27.3°C) during transportation to the flight field as well as during the flight. CONCLUSIONS: The changes in glucose and potassium are consistent with the magnitude and duration of the temperature difference between the flown and stationary samples. Long drone flights of biological samples are feasible but require stringent environmental controls to ensure consistent results.

Management of Patients with Predicted Difficult Airways in an Academic Emergency Department.

BACKGROUND: Patients with difficult airways are sometimes encountered in the emergency department (ED), however, there is a little data available regarding their management. OBJECTIVES: To determine the incidence, management, and outcomes of patients with predicted difficult airways in the ED. METHODS: Over the 1-year period from July 1, 2015 to June 30, 2016, data were prospectively collected on all patients intubated in an academic ED. After each intubation, the operator completed an airway management data form. Operators performed a pre-intubation difficult airway assessment and classified patients into routine, challenging, or difficult airways. All non-arrest patients were included in the study. RESULTS: There were 456 patients that met inclusion criteria. Fifty (11%) had predicted difficult airways. In these 50 patients, neuromuscular blocking agents (NMBAs) were used in 40 (80%), an awake intubation technique with light sedation was used in 7 (14%), and no medications were used in 3 (6%). In the 40 difficult airway patients who underwent NMBA facilitated intubation, a video laryngoscope (GlideScope 21, Verathon, Bothell, WA and C-MAC 19, Karl Storz, Tuttlingen, Germany) was used in each of these, with a first-pass success of 90%. In the 7 patients who underwent awake intubation, a video laryngoscope was used in 5, and a flexible fiberoptic scope was used in 2. Ketamine was used in 6 of the awake intubations. None of these difficult airway patients required rescue with a surgical airway. CONCLUSIONS: Difficult airways were predicted in 11% of non-arrest patients requiring intubation in the ED, the majority of which were managed using an NMBA and a video laryngoscope with a high first-pass success.

Optical design considerations for efficient light collection from liquid scintillation counters.

Liquid scintillation counters measure charged particle-emitting radioactive isotopes and are used for environmental studies, nuclear chemistry, and life science. Alpha and beta emissions arising from the material under study interact with the scintillation cocktail to produce light. The prototypical liquid scintillation counter employs low-level photon-counting detectors to measure the arrival of the scintillation. For reliable operation, the counting instrument must convey the scintillation light to the detectors efficiently and predictably. Current best practices employ the use of two or more detectors for coincidence processing to discriminate true scintillation events from background events due to instrumental effects such as photomultiplier tube dark rates, tube flashing, or other light emission not generated in the scintillation cocktail vial. In low-background liquid scintillation counters, additional attention is paid to shielding the scintillation cocktail from naturally occurring radioactive material present in the laboratory and within the instrument's construction materials. Low-background design is generally at odds with optimal light collection. This study presents the evolution of a light collection design for liquid scintillation counting (LSC) in a low-background shield. The basic approach to achieve both good light collection and a low-background measurement is described. The baseline signals arising from the scintillation vial are modeled and methods to efficiently collect scintillation light are presented as part of the development of a customized low-background, high-sensitivity LSC system.

Can emergency physicians perform common carotid Doppler flow measurements to assess volume responsiveness?

INTRODUCTION: Common carotid flow measurements may be clinically useful to determine volume responsiveness. The objective of this study was to assess the ability of emergency physicians (EP) to obtain sonographic images and measurements of the common carotid artery velocity time integral (VTi) for potential use in assessing volume responsiveness in the clinical setting. METHODS: In this prospective observational study, we showed a five-minute instructional video demonstrating a technique to obtain common carotid ultrasound images and measure the common carotid VTi to emergency medicine (EM) residents. Participants were then asked to image the common carotid artery and obtain VTi measurements. Expert sonographers observed participants imaging in real time and recorded their performance on nine performance measures. An expert sonographer graded image quality. Participants were timed and answered questions regarding ease of examination and their confidence in obtaining the images. RESULTS: A total of 30 EM residents participated in this study and each performed the examination twice. Average time required to complete one examination was 2.9 minutes (95% CI [2.4-3.4 min]). Participants successfully completed all performance measures greater than 75% of the time, with the exception of obtaining measurements during systole, which was completed in 65% of examinations. Median resident overall confidence in accurately performing carotid VTi measurements was 3 (on a scale of 1 [not confident] to 5 [confident]). CONCLUSION: EM residents at our institution learned the technique for obtaining common carotid artery Doppler flow measurements after viewing a brief instructional video. When assessed at performing this examination, they completed several performance measures with greater than 75% success. No differences were found between novice and experienced groups.

Detection of in vivo enzyme activity with CatalyCEST MRI.

PURPOSE: CatalyCEST MRI compares the detection of an enzyme-responsive chemical exchange saturation transfer (CEST) agent with the detection of an unresponsive "control" CEST agent that accounts for other conditions that influence CEST. The purpose of this study was to investigate the feasibility of in vivo catalyCEST MRI. METHODS: CEST agents that were responsive and unresponsive to the activity of urokinase plasminogen activator were shown to have negligible interaction with each other. A CEST-fast imaging with steady state precession (FISP) MRI protocol was used to acquire MR CEST spectroscopic images with a Capan-2 pancreatic tumor model after intravenous injection of the CEST agents. A function of (super)-Lorentzian line shapes was fit to CEST spectra of a region-of-interest that represented the tumor. RESULTS: The CEST effects from each agent showed the same initial uptake into tumor tissues, indicating that both agents had the same pharmacokinetic transport rates. Starting 5 min after injection, CEST from the enzyme-responsive agent disappeared more quickly than CEST from the unresponsive agent, indicating that the enzyme responsive agent was being catalyzed by urokinase plasminogen activator, while both agents also experienced net pharmacokinetic washout from the tumor. CONCLUSION: CatalyCEST MRI demonstrates that dynamic tracking of enzyme-responsive and unresponsive CEST agents during the same in vivo MRI study is feasible.

Immediate effects of cryotherapy on static and dynamic balance.

PURPOSE/BACKGROUND: Cryotherapy is commonly used in physical therapy with many known benefits; however several investigations have reported decreased functional performance following therapeutic application thereof. The purpose of this study was to determine the effect of cryotherapy applied to the ankle on static and dynamic standing balance. It was hypothesized that balance would be decreased after cryotherapy application. METHODS: Twenty individuals (aged 18 to 40 years) participated in this research project. Each participant was tested under two conditions: an experimental condition where subjects received ice water immersion of the foot and ankle for 15 minutes immediately before balance testing and a control condition completed at room temperature. A Biodex® Balance System was used to quantify balance using anterior/posterior (AP), medial/lateral (ML), and overall balance indices. Paired t-tests were used to compare the balance indices for the two conditions with alpha set at 0.05 a priori. Effect size was also calculated to account for the multiple comparisons made. RESULTS: The static balance indices did not display statistically significant differences between the post-cryotherapy and the control conditions with low effect sizes. Dynamic ML indices significantly increased following the cryotherapy application compared to the control exhibiting a moderate effect size indicating decreased balance following cryotherapy application. No differences were noted between experimental and control conditions for the dynamic AP or overall balance indices while a small effect size was noted for both. CONCLUSIONS: The results suggest that cryotherapy to the ankle has a negative effect on the ML component of dynamic balance following ice water immersion. CLINICAL RELEVANCE: Immediate return to play following cryotherapy application is cautioned given the decreased dynamic ML balance and potential for increased injury risk. LEVEL OF EVIDENCE: 3b Case-control study.

Extraction chromatographic methods in the sample preparation sequence for thermal ionization mass spectrometric analysis of plutonium isotopes.

A sample preparation sequence for actinide isotopic analysis by thermal ionization mass spectrometry (TIMS) is described that includes column-based extraction chromatography as the first separation step, followed by anion-exchange column separations. The sequence is designed to include a wet ashing step after the extraction chromatography to prevent any leached extractant or oxalic acid eluent reagents from interfering with subsequent separations, source preparation, or TIMS ionization. TEVA resin and DGA resin materials, containing extractants that consist only of C, N, O, and H atoms, were investigated for isolation of plutonium. Radiotracer level studies confirmed expected high yields from column-based separation procedures. Femtogram-level studies were carried out with TIMS detection, using multiple monoisotopic spikes applied sequentially throughout the separation sequence. Pu recoveries were 87% and 86% for TEVA and DGA resin separations, respectively. The Pu recoveries from 400 µL anion-exchange column separation sequences were 89% and 93% for trial sequences incorporating TEVA and DGA resin. Thus, a prior extraction chromatography step in the sequence did not interfere with the subsequent anion-exchange separation when a simple wet ash step was carried out in between these column separations. The average measurement efficiency for Pu, encompassing the chemical separation recoveries and the TIMS ionization efficiency, was 2.73% ± 0.77% (2σ) for the DGA resin trials and 2.67% ± 0.54% for the TEVA resin trials, compared to 3.41% and 2.37% (average 2.89%) for two control trials. These compare with an average measurement efficiency of 2.78% ± 1.70%, n = 33 from process benchmark analyses using Pu spikes processed through a sequence of oxalate precipitation, wet ash, iron hydroxide precipitation, and anion-exchange column separations. We conclude that extraction chromatography can be a viable separation procedure as part of a multistep sequence for TIMS sample preparation.

Uranium extraction from laboratory-synthesized, uranium-doped hydrous ferric oxides.

The extractability of uranium (U) from synthetic uranium-hydrous ferric oxide (HFO) coprecipitates has been shown to decrease as a function of mineral ripening, consistent with the hypothesis that the ripening process will decrease uranium lability. To evaluate this process, three HFO suspensions were coprecipitated with uranyl (UO2(2+)) and maintained at pH 7.0 +/- 0.1. Uranyl was added to the HFO postprecipitation in a fourth suspension. Two suspensions also contained either coprecipitated silicate (Si-U-HFO) or phosphate (P-U-HFO). After precipitation of the HFOs, at time intervals of 1 week, 1 month, 6 months, 1 year, and 2 years, aliquots of each suspension were contacted with five extractant solutions for a range of time. Uranium was preferentially extracted over Fe in varying degrees from all coprecipitates, by all extractants. The preference was dependent on the duration of mineral ripening and adjunct anion. Micro-X-ray diffraction analysis provides evidence for the transformation from amorphous material to phases containing substantial proportions of crystalline goethite and hematite, except the P-U-HFO, which remained primarily amorphous. Analysis of the U-HFO coprecipitate bythe Mössbauertechnique and scanning electron microscopy provides confirmation of an increase in particle size and evidence of mineral ripening to crystalline phases.

Ultra-low level plutonium isotopes in the NIST SRM 4355A (Peruvian Soil-1).

For more than 20 years, countries and their agencies which monitor radionuclide discharge sites and storage facilities have relied on the National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 4355 Peruvian Soil. Its low fallout contamination makes it an ideal soil blank for measurements associated with terrestrial-pathway-to-man studies. Presently, SRM 4355 is out of stock, and a new batch of the Peruvian soil is currently under development as future NIST SRM 4355A. Both environmental radioanalytical laboratories and mass spectrometry communities will benefit from the use of this SRM. The former must assess their laboratory procedural contamination and measurement detection limits by measurement of blank sample material. The Peruvian Soil is so low in anthropogenic radionuclide content that it is a suitable virtual blank. On the other hand, mass spectrometric laboratories have high sensitivity instruments that are capable of quantitative isotopic measurements at low plutonium levels in the SRM 4355 (first Peruvian Soil SRM) that provided the mass spectrometric community with the calibration, quality control, and testing material needed for methods development and legal defensibility. The quantification of the ultra-low plutonium content in the SRM 4355A was a considerable challenge for the mass spectrometric laboratories. Careful blank control and correction, isobaric interferences, instrument stability, peak assessment, and detection assessment were necessary. Furthermore, a systematic statistical evaluation of the measurement results and considerable discussions with the mass spectroscopy metrologists were needed to derive the certified values and uncertainties. The one sided upper limit of the 95% tolerance with 95% confidence for the massic (239)Pu content in SRM 4355A is estimated to be 54,000 atoms/g.

Nuclear archeology in a bottle: evidence of pre-Trinity U.S. weapons activities from a waste burial site.

During World War II, the Hanford Site in Washington became the location for U.S. plutonium production. In 2004, a bottle containing a sample of plutonium was recovered from a Hanford waste trench. Here, state-of-the-art instrumental analyses, reactor model simulations, and investigative science techniques were used to provide insights as to the origin of this unknown sample, a process collectively termed as nuclear archeology. Isotopic age dating conducted on the sample in 2007 indicated the sample was separated from the spent fuel 61.6 +/- 4.5 years earlier. The isotope (22)Na, a detectable product of a secondary nuclear reaction, proved useful as a powerful tool for nuclear forensic analysis as (1) an easily detectable signifier of the presence of alpha emitting actinides, (2) an indicator of sample splitting, and (3) a measure of the time since sample splitting. Analytical results of minor actinide isotopes and reactor model simulations confirmed the material originated from the X-10 reactor in Oak Ridge, TN. Corroborated by historical documents, we concluded this sample was part of the first batch of Pu separated at T-Plant, Hanford, the world's first industrial-scale reprocessing facility, on December 9, 1944. This sample represents the oldest known collection of man-made (239)Pu in the world.