Rapid Separation of Photofissioned Uranium Products via a Single-Pass Multiplexed Chromatographic Fission Product Separation System.

Current state-of-the-art fission product separations frequently involve multiple independent separation columns and sample manipulation processes; to couple these processes together, multiple evaporation and transposition steps are often required. The addition of these steps results in lengthy separation times, increased analysis costs, the potential for sample loss, and release of radioactive contamination. We report a new semiautomated method for the rapid separation of U, Zr, Mo, Ba, Sr, Te, and lanthanide fission products from irradiated uranium samples. Chemical yields for U, Zr, Ba, Sr, Te and the lanthanides from less than 3-day old uranium fission product samples are consistently greater than 90%, while those of Mo are greater than 70%. This method minimizes the use and addition of oxidation and reduction reagents that often cause issues with retention and separation. Uranium dissolution and fission product separations using this single-pass method are achievable in under 2 h, representing a significant improvement over traditional gravimetric uranium fission product separation procedures.

Guiding therapeutic plasma exchange for antibody-mediated rejection treatment in lung transplant recipients - a retrospective study.

Antibody-Mediated Rejection (AMR) due to donor-specific antibodies (DSA) is associated with poor outcomes after lung transplantation. Currently, there are no guidelines regarding the selection of treatment protocols. We studied how DSA characteristics including titers, C1q, and mean fluorescence intensity (MFI) values in undiluted and diluted sera may predict a response to therapeutic plasma exchange (TPE) and inform patient prognosis after treatment. Among 357 patients consecutively transplanted without detectable pre-existing DSAs between 01/01/16 and 12/31/18, 10 patients were treated with a standardized protocol of five TPE sessions with IVIG. Based on DSA characteristics after treatment, all patients were divided into three groups as responders, partial responders, and nonresponders. Kaplan-Meier Survival analyses showed a statistically significant difference in patient survival between those groups (P = 0.0104). Statistical analyses showed that MFI in pre-TPE 1:16 diluted sera was predictive of a response to standardized protocol (R2  = 0.9182) and patient survival (P = 0.0098). Patients predicted to be nonresponders who underwent treatment with a more aggressive protocol of eight TPE sessions with IVIG and bortezomib showed improvements in treatment response (P = 0.0074) and patient survival (P = 0.0253). Dilutions may guide clinicians as to which patients would be expected to respond to a standards protocol or require more aggressive treatment.

Development of a Quality Improvement Curriculum in a Pediatric Emergency Medicine Fellowship.

Quality improvement (QI) is a science of systematic analysis and improvement of health care delivery systems. Working knowledge of QI models is imperative to professional development of future pediatric emergency medicine practitioners. The Accreditation Council for Graduate Medical Education has established a list of QI and patient safety expectations for trainees. In order to address educational needs in this area, we have created a novel QI curriculum for pediatric emergency medicine fellows that include didactic sessions, active participation in QI projects, and mentorship by QI faculty. As a part of the curriculum, fellows are required to participate in variety of QI and patient safety activities, such as Morbidity and Mortality conferences, QI and Patient Case Review committees, and Clinical Care Guideline work groups. As a measure of success, fellows who have participated in this curriculum have shared their successful QI work at the local and national levels. This goal of this report is to share our experience in order to provide other institutions a framework for their own curriculum development.

High power narrow linewidth discrete mode laser diode integrated with a curved semiconductor optical amplifier emitting at 2051 nm.

We report on a 2.051 µm InxGaAs/InP-based discrete mode laser diode monolithically integrated with a curved tapered semiconductor optical amplifier for CO2 sensing applications. At a heat-sink temperature of 0°C, the laser emits a record InP value of more than 35 mW continuous-wave output power in a single longitudinal mode.

Synthesis and Crystal Structures of Volatile Neptunium(IV) ß-Diketonates.

Production of certified reference materials in support of domestic nuclear forensics programs require volatile precursors for introduction into electromagnetic isotopic separation instruments. ß-Diketone chelates of tetravalent actinides are known for their high volatility, but previously developed synthetic approaches require starting material (NpCl4) that is prohibitively difficult and hazardous to prepare. An alternative strategy was developed here that uses controlled potential electrolysis to reduce neptunium to the tetravalent state in submolar concentrations of hydrochloric acid. Four different ß-diketone ligands of varying degrees of fluorination were reacted with an aqueous solution of Np4+. Products of this reaction were characterized via X-ray diffraction and infrared spectroscopy, and were found to be neutral 8-coordinate complexes that adopt square antiprismatic crystal geometry. Synthesis of Np ß-diketonates by this approach circumvents the necessity of using NpCl4 in tetravalent Np coordination compound synthesis. The volatility of the complexes was assessed using thermogravimetric analysis, where the temperature of sublimation was determined to be in the range of 180° to 205 °C. The extent of fluorination did not appreciably alter the sublimation temperature of the complex. Thermal decomposition of these compounds was not observed during sublimation. High volatility and thermal stability of Np ß-diketonates make them ideal candidates for gaseous introduction into isotopic separation instruments.

Lung volume reduction surgery is safe and leads to functional improvement in patients who fail or cannot undergo bronchoscopic lung volume reduction.

Background: Bronchoscopic lung volume reduction (BLVR) has supplanted surgery in the treatment of patients with advanced emphysema, but not all patients qualify for it. Our study aimed to investigate the outcomes of lung volume reduction surgery (LVRS) among patients who either failed BLVR or were not candidates for it. Methods: We conducted a retrospective analysis of patients who underwent LVRS for upper lobe-predominant emphysema at a single tertiary center between March 2018 and December 2022. The main outcomes measures were preoperative and postoperative respiratory parameters, perioperative morbidity, and mortality. Results: A total of 67 LVRS recipients were evaluated, including 10 who had failed prior valve placement. The median patient age was 69 years, and 35 (52%) were male. All procedures were performed thoracoscopically, with 36 patients (53.7%) undergoing bilateral LVRS. The median hospital length of stay was 7 days (interquartile range, 6-11 days). Prolonged air leak (>7 days) occurred in 20 patients. There was one 90-day mortality from a nosocomial pneumonia (non-COVID-related) and no further deaths at 12 months. There were mean improvements of 10.07% in forced expiratory volume in 1 second and 4.74% in diffusing capacity of the lung for carbon monoxide, along with a mean decrease 49.2% in residual volume (P < .001 for all). The modified Medical Research Council dyspnea scale was improved by 1.84 points (P < .001). Conclusions: LVRS can be performed safely in patients who are not candidates for BLVR and those who fail BLVR and leads to significant functional improvement. Long-term follow-up is necessary to ensure the sustainability of LVRS benefits in this patient population.

Method to improve the noise figure and saturation power in multi-contact semiconductor optical amplifiers: simulation and experiment.

The consequences of tailoring the longitudinal carrier density along the active layer of a multi-contact bulk semiconductor optical amplifier (SOA) are investigated using a rate equation model. It is shown that both the noise figure and output power saturation can be optimized for a fixed total injected bias current. The simulation results are validated by comparison with experiment using a multi-contact SOA. The inter-contact resistance is increased using a focused ion beam in order to optimize the carrier density control. A chip noise figure of 3.8 dB and a saturation output power of 9 dBm are measured experimentally for a total bias current of 150 mA.

Strategic Surge Responses in the COVID-19 era: Operational Themes, Innovative Solutions and Lessons Learned by Three Freestanding Pediatric Emergency Departments.

The prolonged COVID-19 pandemic has created unique and complex challenges in operational and capacity planning for pediatric emergency departments, as initial low pediatric patient volumes gave way to unpredictable patient surges during Delta and Omicron variants. Compounded by widespread hospital supply chain issues, staffing shortages due to infection and attrition, and a concurrent pediatric mental health crisis, the surges have pushed pediatric emergency department leaders to re-examine traditionally defined clinical processes, and adopt innovative operational strategies. This study describes the strategic surge response and lessons learned by 3 major freestanding academic pediatric emergency departments in the western United States to help inform current and future pediatric pandemic preparedness.

Impact of bias current distribution on the noise figure and power saturation of a multicontact semiconductor optical amplifier.

We present an experimental investigation of a multicontact semiconductor optical amplifier. This first-generation device allows for direct control of the carrier density profile along the length of the waveguide. This is used to control the device noise figure, with a minimum value of 5 dB observed at a gain of 15 dB for an optimum carrier density profile. The opposite carrier density profile results in an increase of the power saturation by 3 dB.

High purity 47Sc production using high-energy photons and natural vanadium targets.

Scandium-47 (47Sc) is of high value for targeted radiotherapy and theranostics; we report a novel, cost-effective approach to produce high-purity 47Sc via photonuclear reactions with natural vanadium. Irradiation at 20 MeV photon end-point energy produces >99.998% pure 47Sc, while irradiation at 38 MeV produces 98.8 ± 1.6% pure 47Sc. Experimental data suggest producing greater than 100 mCi (3700 MBq) of 47Sc using this approach may be feasible. Future research into refinement and scale-up to support pre-clinical research is recommended.

A Front-end Redesign With Implementation of a Novel "Intake" System to Improve Patient Flow in a Pediatric Emergency Department.

INTRODUCTION: Children's Hospital Colorado is an academic, tertiary-care Level 1 Trauma Center with an emergency department (ED) that treats >70,000 patients/year. Patient volumes continue to increase, leading to worsening wait times and left-without-being-seen (LWBS) rates. In 2015, the ED's median door-to-provider time was 49 minutes [interquartile range (IQR) = 26-90], with a 3.2% LWBS rate. ED leadership, staff, and providers aimed to improve patient flow with specific goals to (1) decrease door-to-provider times to a median of <30 minutes and (2) decrease annual LWBS rate to <1%. METHODS: An inter-professional team utilized quality improvement and Lean methodology to study, redesign, and implement significant changes to ED front-end processes. Key process elements included (1) new Flow Nurse/EMT roles, (2) elimination of traditional registration and triage processes, (3) immediate "quick registration" and nurse assessment upon walk-in, (4) direct-bedding of patients, and (5) a novel "Intake" system staffed by a pediatric emergency medicine physician. RESULTS: In the 12 months following full implementation of the new front-end system, the median door-to-provider time decreased 49% to 25 minutes (IQR = 13-50), and the LWBS rate decreased from 3.2% to 1.4% (a 56% relative decrease). Additionally, the percentage of patients seen within 30 minutes of arrival increased, overall ED length-of-stay decreased, patient satisfaction improved, and no worsening of the unexpected 72-hour return rate occurred. CONCLUSIONS: Using quality improvement and Lean methodology, an inter-professional team decreased door-to-provider times and LWBS rates in a large pediatric ED by redesigning its front-end processes and implementing a novel pediatric emergency medicine-led Intake system.

Lung Transplant for the Critical Care Nurse.

Lung transplantation is an established treatment of select patients with end-stage pulmonary disease. Lung transplantation should be considered for patients with end-stage pulmonary disease who have an expected 2-year survival of less than 50% without lung transplant and an expected 5-year survival of greater than 80% after transplant. This article reviews routine postsurgical intensive care unit management, along with management of complications such as acute kidney injury, atrial arrhythmias, deep vein thrombosis, primary graft dysfunction, hyperammonemia syndrome, and thrombocytopenia. Finally, management of long-term issues, including diabetes mellitus, hypertension, and bronchial stenosis, is discussed.

A reference material for evaluation of 137 Cs radiochronometric measurements.

A new nuclear forensic reference material has been characterized as a standard for radiochronometric determination of the model purification date for 137Cs sources. The purification date of a radioactive source is a potentially diagnostic nuclear forensic signature for determining the provenance of a radioactive material. Reference values have been measured for the attributes needed to use the 137Cs/137Ba chronometer: the molality (reported here as nmol g-1) of 137Cs and of the radiogenic portion of 137Ba in the material (hereafter referred to as 137Ba*). All measurement results were decay-corrected to represent the composition of the material on the reference date of July 7, 2011. The molality of 137Cs is (0.7915 ± 0.0073) nmol g-1; this value was calculated from the massic activity of 137Cs, (348.4 ± 3.0) kBq g-1, as measured in the NIST 4π-γ secondary standard ionization chamber (previously calibrated by 4π-(e+x)-γ-coincidence efficiency extrapolation counting) and the evaluated half-life of 137Cs, (30.05 ± 0.08) years. The molality of 137Ba*, (1.546 ± 0.024) nmol g-1, was measured by isotope dilution mass spectrometry using the measured relative proportion of 138Ba in the material to apply a correction for the 137Ba contribution from natural Ba. A model age of (47.04 ± 0.56) years, corresponding to a model purification date of June 22, 1964 with an expanded uncertainty of 200 days is calculated from the reference material values. This age is consistent with the date engraved on the capsule that contained the 137Cs starting material and with a prior independent determination of the model purification date. A full discussion of the uncertainties of the reference material values is included.

A composite position independent monitor of reactor fuel irradiation using Pu, Cs, and Ba isotope ratios.

When post-irradiation materials from the nuclear fuel cycle are released to the environment, certain isotopes of actinides and fission products carry signatures of irradiation history that can potentially aid a nuclear forensic investigation into the material's provenance. In this study, combinations of Pu, Cs, and Ba isotope ratios that produce position (in the reactor core) independent monitors of irradiation history in spent light water reactor fuel are identified and explored. These position independent monitors (PIMs) are modeled for various irradiation scenarios using automated depletion codes as well as ordinary differential equation solutions to approximate nuclear physics models. Experimental validation was performed using irradiated low enriched uranium oxide fuel from a light water reactor, which was sampled at 8 axial positions from a single rod. Plutonium, barium and cesium were chemically separated and isotope ratio measurements of the separated solutions were made by quadrupole and multi-collector inductively coupled mass spectrometry (Cs and Pu, respectively) and thermal ionization mass spectrometry (Ba). The effect of axial variations in neutron fluence and energy spectrum are evident in the measured isotope ratios. Two versions of a combined Pu and Cs based PIM are developed. A linear PIM model, which can be used to solve for irradiation time is found to work well for natural U fuel with <10% 240Pu and known or short cooling times. A non-linear PIM model, which cannot be solved explicitly for irradiation time without additional information, can nonetheless still group samples by irradiation history, including high burnup LEU fuel with unknown cooling time. 137Ba/138Ba is also observed to act as a position independent monitor; it is nearly single valued across the sampled fuel rod, indicating that samples sharing an irradiation history (same irradiation time and cooling time) in a reactor despite experiencing different neutron fluxes will have a common 137Ba/138Ba ratio. Modeling of this Ba PIM shows it increases monotonically with irradiation and cooling time, and a confirmatory first order analytical solution is also presented.

Extraction chromatographic separations of tantalum and tungsten from hafnium and complex matrix constituents.

Tantalum (Ta), hafnium (Hf), and tungsten (W) analyses from complex matrices require high purification of these analytes from each other and major/trace matrix constituents, however, current state-of-the-art Ta/Hf/W separations rely on traditional anion exchange approaches that show relatively similar distribution coefficient (Kd) values for each element. This work reports an assessment of three commercially available extraction chromatographic resins (TEVA, TRU, and UTEVA) for Ta/Hf/W separations. Batch contact studies show differences in Ta/Hf and Ta/W Kd values of up to 106 and 104 (respectively), representing an improvement of a factor of 100 and 300 in Ta/Hf and Ta/W Kd values (respectively) over AG1×4 resin. Variations in the Kd values as a function of HCl concentration for TRU resin show that this resin is well suited for Ta/Hf/W separations, with Ta/Hf, Ta/W, and W/Hf Kd value improvements of 10, 200, and 30 (respectively) over AG1×4 resin. Analyses of digested soil samples (NIST 2710a) using TRU resin and tandem TEVA-TRU columns demonstrate the ability to achieve extremely high purification (>99%) of Ta and W from each other and Hf, as well as enabling very high purification of Ta and W from the major and trace elemental constituents present in soils using a single chromatographic step.

Massive donor transfusion potentially increases recipient mortality after lung transplantation.

OBJECTIVE: Donor blood transfusion has been identified as a potential risk factor for primary graft dysfunction and by extension early mortality. We sought to define the contributing risk of donor transfusion on early mortality for lung transplant. METHODS: Donor and recipient data were abstracted from the Organ Procurement and Transplantation Network database updated through June 30, 2014, which included 86,398 potential donors and 16,255 transplants. Using the United Network for Organ Sharing 4-level designation of transfusion (no blood, 1-5 units, 6-10 units, and >10 units, massive), we analyzed all-cause mortality at 30-days with the use of logistic regression adjusted for confounders (ischemic time, donor age, recipient diagnosis, lung allocation score and recipient age, and recipient body mass index). Secondary analyses assessed 90-day and 1-year mortality and hospital length of stay. RESULTS: Of the 16,255 recipients transplanted, 8835 (54.35%) donors received at least one transfusion. Among those transfused, 1016 (6.25%) received a massive transfusion, defined as >10 units. Those donors with massive transfusion were most commonly young trauma patients. After adjustment for confounding variables, donor massive transfusion was associated significantly with an increased risk in 30-day (P = .03) and 90-day recipient mortality (P = .01) but not 1-year mortality (P = .09). There was no significant difference in recipient length of stay or hospital-free days with respect to donor transfusion. CONCLUSIONS: Massive donor blood transfusion (>10 units) was associated with early recipient mortality after lung transplantation. Conversely, submassive donor transfusion was not associated with increased recipient mortality. The mechanism of increased early mortality in recipients of lungs from massively transfused donors is unclear and needs further study but is consistent with excess mortality seen with primary graft dysfunction in the first 90 days posttransplant.

Relationship of race to sudden cardiac death in competitive athletes with hypertrophic cardiomyopathy.

OBJECTIVES: The goal of this study was to determine the impact of race on identification of hypertrophic cardiomyopathy (HCM). BACKGROUND: Sudden death in young competitive athletes is due to a variety of cardiovascular diseases (CVDs) and, most commonly, HCM. These catastrophes have become an important issue for African Americans, although HCM has been previously regarded as rare in this segment of the U.S. population. METHODS: We studied the relationship of race to the prevalence of CVDs causing sudden death in our national athlete registry, and compared these findings with a representative multicenter hospital-based cohort of patients with HCM. RESULTS: Of 584 athlete deaths, 286 were documented to be due to CVD at ages 17 +/- 3 years; 156 (55%) were white, and 120 (42%) were African American. Most were male (90%), and 67% participated in basketball and football. Among the 286 cardiovascular deaths, most were due to HCM (n = 102; 36%) or anomalous coronary artery of wrong sinus origin (n = 37; 13%). Of the athletes who died of HCM, 42 (41%) were white, but 56 (55%) were African American. In contrast, of 1,986 clinically identified HCM patients, only 158 (8%) were African American (p < 0.001). CONCLUSIONS: In this autopsy series, HCM represented a common cause of sudden death in young and previously undiagnosed African American male athletes, in sharp contrast with the infrequent clinical identification of HCM in a hospital-based population (i.e., by seven-fold). This discrepancy suggests that many HCM cases go unrecognized in the African American community, underscoring the need for enhanced clinical recognition of HCM to create the opportunity for preventive measures to be employed in high-risk patients with this complex disease.