ABSTRACT
Background: Shoulder and elbow function is essential to basic basketball actions. Outside of anterior shoulder instability, injuries in these joints are not well characterized in National Basketball Association (NBA) players. Purpose: To describe the epidemiology and associated risk factors of shoulder and elbow injuries in NBA players and identify factors that influence player performance upon return to play. Study Design: Descriptive epidemiology study. Methods: Historical injury data from the 2015-2020 NBA seasons were retrieved from Pro Sports Transactions, a public online database. An injury was defined as a health-related concern resulting in an absence of ≥1 NBA games. Primary measures included pre- and postinjury player efficiency rating (PER) and true shooting percentage (TS%) with interquartile ranges (IQRs), stratified by extremity dominance. Multivariate logistic regression analyses with stepwise regression were performed to identify risk factors associated with return-to-play performance. Results: A total of 192 shoulder and elbow injuries were sustained among 126 NBA athletes, with incidence rates of 1.11 per 1000 game exposures (GEs) and 0.30 per 1000 GEs, respectively. Sprain/strain and general soreness were the most common injury types in both the shoulder and the elbow. In the 2 years after injury, baseline PER was achieved in all groups, except for players with dominant shoulder injuries (baseline PER, 16 [IQR, 14-18] vs 2-year PER, 13 [IQR 11-16]; P = .012). Younger age was associated with quicker return to baseline PER (odds ratio, 0.77 [95% CI, 0.67-0.88]). Shoulder and elbow injuries did not negatively influence TS% upon return to play (baseline TS%, 0.55% [IQR, 0.51%-0.58%] vs 1-year TS%, 0.55% [IQR, 0.52%-0.58%]; P = .13). Conclusion: Dominant shoulder injuries negatively influenced PER during the first 2 seasons upon return to play in NBA players. Therefore, expectations that players with this type of injury immediately achieve baseline statistical production should be tempered. Shooting accuracy appears to remain unaffected after shoulder or elbow injury.
ABSTRACT
Background: Health and safety concerns surrounding the coronavirus 2019 (COVID-19) pandemic led the National Basketball Association (NBA) to condense and accelerate the 2020 season. Although prior literature has suggested that inadequate rest may lead to an increased injury risk, the unique circumstances surrounding this season offer a unique opportunity to evaluate player safety in the setting of reduced interval rest. Hypothesis: We hypothesized that the condensed 2020 NBA season resulted in an increased overall injury risk as compared with the 2015 to 2018 seasons. Study Design: Descriptive epidemiology study. Methods: A publicly available database, Pro Sports Transactions, was queried for injuries that forced players to miss ≥1 game between the 2015 and 2020 seasons. Data from the 2019 season were omitted given the abrupt suspension of the league year. All injury incidences were calculated per 1000 game-exposures (GEs). The primary outcome was the overall injury proportion ratio (IPR) between the 2020 season and previous seasons. Secondary measures included injury incidences stratified by type, severity, age, position, and minutes per game. Results: A total of 4346 injuries occurred over a 5-season span among 2572 unique player-seasons. The overall incidence of injury during the 2020 season was 48.20 per 1000 GEs but decreased to 39.97 per 1000 GEs when excluding COVID-19. Despite this exclusion, the overall injury rate in 2020 remained significantly greater (IPR, 1.42 [95% CI, 1.32-1.52]) than that of the 2015 to 2018 seasons (28.20 per 1000 GEs). On closer evaluation, the most notable increases seen in the 2020 season occurred within minor injuries requiring only a 1-game absence (IPR, 1.53 [95% CI, 1.37-1.70]) and in players who were aged 25 to 29 years (IPR, 1.57 [95% CI, 1.40-2.63]), averaging ≥30.0 minutes per game (IPR, 1.67 [95% CI, 1.47-1.90]), and playing the point guard position (IPR, 1.67 [95% 1.44-1.95]). Conclusion: Players in the condensed 2020 NBA season had a significantly higher incidence of injuries when compared with the prior 4 seasons, even when excluding COVID-19-related absences. This rise is consistent with the other congested NBA seasons of 1998 and 2011. These findings suggest that condensing the NBA schedule is associated with an increased risk to player health and safety.
ABSTRACT
Inspired Therapeutics (Merritt Island, FL) is developing a mechanical circulatory support (MCS) system designed as a single driver with interchangeable, extracorporeal, magnetically levitated pumps. The NeoMate system design features an integrated centrifugal rotary pump, motor, and controller that will be housed in a single compact unit. Conceptually, the primary innovation of this technology will be the combination of disposable, low-cost pumps for use with a single, multi-functional, universal controller to support multiple pediatric cardiopulmonary indications. In response to the paucity of clinically available pediatric devices, Inspired Therapeutics is specifically targeting the underserved neonate and infant heart failure (HF) patient population first. In this article, we present the development of the prototype Inspired Therapeutics NeoMate System for pediatric left ventricular assist device (LVAD) support, and feasibility testing in static mock flow loops (H-Q curves), dynamic mock flow loops (hemodynamics), and in an acute healthy ovine model (hemodynamics and clinical applicability). The resultant hydrodynamic and hemodynamic data demonstrated the ability of this prototype pediatric LVAD and universal controller to function over a range of rotary pump speeds (500-6000 RPM), to provide pump flow rates of up to 2.6 L/min, and to volume unload the left ventricle in acute animals. Key engineering challenges observed and proposed solutions for the next design iteration are also presented.
Subject(s)
Heart Failure , Heart-Assist Devices , Animals , Child , Equipment Design , Feasibility Studies , Heart Failure/therapy , Hemodynamics/physiology , Humans , Infant, Newborn , SheepABSTRACT
PURPOSE: Pediatric heart failure patients remain in critical need of a dedicated mechanical circulatory support (MCS) solution as development efforts for specific pediatric devices continue to fall behind those for the adult population. The Inspired Pediatric VAD is being developed as a pediatric specific MCS solution to provide up to 30-days of circulatory or respiratory support in a compact modular package that could allow for patient ambulation during treatment. METHODS: Hydrodynamic performance (flows, pressures), impeller/rotor mechanical properties (torques, forces), and flow shear stress and residence time distributions of the latest design version, Inspired Pediatric VAD V3, were numerically predicted and investigated using computational fluid dynamics (CFD) software (SolidWorks Flow Simulator). RESULTS: Hydrodynamic performance was numerically predicted, indicating no change in flow and pressure head compared to the previous device design (V2), while displaying increased impeller/rotor torques and translation forces enabled by improved geometry. Shear stress and flow residence time volumetric distributions are presented over a range of pump rotational speeds and flow rates. At the lowest pump operating point (3000 RPM, 0.50 L/min, 75 mmHg), 79% of the pump volume was in the shear stress range of 0-10 Pa with < 1% of the volume in the critical range of 150-1000 Pa for blood damage. At higher speed and flow (5000 RPM, 3.50 L/min, 176 mmHg), 65% of the volume resided in the 0-10 Pa range compared to 2.3% at 150-1000 Pa. CONCLUSIONS: The initial computational characterization of the Inspired Pediatric VAD V3 is encouraging and future work will include device prototype testing in a mock circulatory loop and acute large animal model.
Subject(s)
Heart Failure , Heart-Assist Devices , Animals , Equipment Design , Heart Failure/therapy , Humans , Hydrodynamics , Pressure , Stress, MechanicalABSTRACT
PURPOSE: Despite the availability of first-generation extracorporeal mechanical circulatory support (MCS) systems that are widely used throughout the world, there is a need for the next generation of smaller, more portable devices (designed without cables and a minimal number of connectors) that can be used in all in-hospital and transport settings to support patients in heart failure. Moreover, a system that can be universally used for all indications for use including cardiopulmonary bypass (CPB), uni- or biventricular support (VAD), extracorporeal membrane oxygenation (ECMO) and respiratory assist that is suitable for use for adult, neonate, and pediatric patients is desirable. Providing a single, well designed, universal technology could reduce the incidence of human errors by limiting the need for training of hospital staff on a single system for a variety of indications throughout the hospital rather than having to train on multiple complex systems. The objective of this manuscript is to describe preliminary research to develop the first prototype pump for use as a ventricular assist device for pediatric patients with the Inspired Universal MCS technology. The Inspired VAD Universal System is an innovative extracorporeal blood pumping system utilizing novel MagLev technology in a single portable integrated motor/controller unit which can power a variety of different disposable pump modules intended for neonate, pediatric, and adult ventricular and respiratory assistance. METHODS: A prototype of the Inspired Pediatric VAD was constructed to determine the hemodynamic requirements for pediatric applications. The magnitude/range of hydraulic torque of the internal impeller was quantified. The hydrodynamic performance of the prototype pump was benchmarked using a static mock flow loop model containing a heated blood analogue solution to test the pump over a range of rotational speeds (500-6000 RPM), flow rates (0-3.5 L/min), and pressures (0 to ~ 420 mmHg). The device was initially powered by a shaft-driven DC motor in lieu of a full MagLev design, which was also used to calculate the fluid torque acting on the impeller. RESULTS: The pediatric VAD produced flows as high as 4.27 L/min against a pressure of 127 mmHg at 6000 RPM and the generated pressure and flow values fell within the desired design specifications. CONCLUSIONS: The empirically determined performance and torque values establish the requirements for the magnetically levitated motor design to be used in the Inspired Universal MagLev System. This next step in our research and development is to fabricate a fully integrated and functional magnetically levitated pump, motor and controller system that meets the product requirement specifications and achieves a state of readiness for acute ovine animal studies to verify safety and performance of the system.
Subject(s)
Heart Failure , Heart-Assist Devices , Animals , Child , Equipment Design , Heart Failure/therapy , Hemodynamics , Humans , Sheep , TorqueABSTRACT
Surgical site infections, defined as acute wound infections requiring surgical intervention within 90 days post-surgery, were retrospectively compared between a novel, zipper-like closure method (ZM) and staples in 682 patients (904 knees) and 772 patients (971 knees), respectively. The incidence of deep infections was 0.6% for staples and 0.2% for ZM (p = 0.169) and superficial infections was 0.1% for staples and 0.0% for ZM (p = 0.518). With no difference in wound complications, the ZM may be preferred since the two-week post-operative clinic visit required for wound check and staple removal was eliminated, thereby, decreasing clinic volume.
ABSTRACT
The Oxford® Partial Knee has excellent long-term survivorship but high surgical times indicate a learn curve. This retrospective review included a radiographic evaluation of component placement of the initial 300 procedures following conversion from fixed bearing implant use. The anteroposterior and sagittal femoral angles were considered inaccurate in 1.7% and 3.9% of cases, respectively. The anteroposterior and sagittal tibial angles were considered inaccurate in 18.7% and 6.0% of cases, respectively. Overall, a learning curve appears to be present regarding the anteroposterior tibial component angle, with the greatest percentage of inaccuracies occurring within the initial 20 cases.
ABSTRACT
In the US, the most significant morbidity and mortality associated with non-valvular atrial fibrillation (NVAF) is embolic stroke, with 90% of thrombus originating from the left atrial appendage (LAA). Anticoagulation is the preferred treatment for the prevention of stroke in NVAF patients, but clinical studies have demonstrated high levels of non-compliance and increased risk of bleeding or ineligibility for anticoagulation therapy, especially in the elderly population where the incidence of NVAF is highest. Alternatively, stroke may be preventing using clinically approved surgical and catheter-based devices to exclude or occlude the LAA, but these devices continue to be plagued by peri-device leaks and thrombus formation because of residual volume. To overcome these limitations, Cor Habere (Louisville, KY) and the University of Louisville are developing a LAA closure device (StrokeShield) that completely occludes and collapses the LAA to minimize the risk of stroke. The StrokeShield device is a collapsible occluder (nitinol reinforced membrane) that completely covers the LAA orifice with an expandable conical coil anchor that attaches to the myocardium. The device is designed for catheter-based delivery and expands to completely occlude the LAA orifice and collapse the LAA. The primary advantages of the StrokeShield system are a completely sealed LAA (no peri-device flow or residual space) and smooth endothelialized connection to the left atrial wall with minimal risk of cardiac bleeding and tamponade. We tested proof-of-concept of a prototype StrokeShield device in acute (n = 2) and chronic 60-day (n = 2) healthy canine models. Acute results demonstrated that the conical coil securely attached to the myocardium (5N pull-out force) and the Nitinol umbrella fully deployed and covered the LAA ostium. Results from the chronic implants demonstrated long-term feasibility of device placement with no procedural or device-related intra- or post-operative complications, secure placement and correct positioning of the device with no device migration. The device successfully occluded the LAA ostium and collapsed the LAA with no interference with the mitral valve, circumflex coronary artery, or pulmonary veins. Necropsy demonstrated no gross signs of thrombus or end-organ damage and the device was encapsulated in the LAA. Histology demonstrated mature neointima covering the device with expected foreign body inflammatory response. These early positive results will help to guide the iterative design process for the continued development of the StrokeShield system.
Subject(s)
Atrial Appendage/surgery , Atrial Fibrillation/therapy , Stroke/prevention & control , Animals , Atrial Appendage/physiopathology , Atrial Fibrillation/complications , Dogs , Embolization, Therapeutic , Male , Proof of Concept Study , Septal Occluder Device , Stroke/etiology , Treatment OutcomeABSTRACT
Pediatric heart failure (HF) patients have been a historically underserved population for mechanical circulatory support (MCS) therapy. To address this clinical need, we are developing a low cost, universal magnetically levitated extracorporeal system with interchangeable pump heads for pediatric support. Two impeller and pump designs (pump V1 and V2) for the pediatric pump were developed using dimensional analysis techniques and classic pump theory based on defined performance criteria (generated flow, pressure, and impeller diameter). The designs were virtually constructed using computer-aided design (CAD) software and 3D flow and pressure features were analyzed using computational fluid dynamics (CFD) analysis. Simulated pump designs (V1, V2) were operated at higher rotational speeds (~5,000 revolutions per minute [RPM]) than initially estimated (4,255 RPM) to achieve the desired operational point (3.5 L/min flow at 150 mm Hg). Pump V2 outperformed V1 by generating approximately 30% higher pressures at all simulated rotational speeds and at 5% lower priming volume. Simulated hydrodynamic performance (achieved flow and pressure, hydraulic efficiency) of our pediatric pump design, featuring reduced impeller size and priming volume, compares favorably to current commercially available MCS devices.
Subject(s)
Heart Failure , Heart-Assist Devices , Child , Equipment Design , Heart Failure/surgery , Humans , Hydrodynamics , Prosthesis DesignABSTRACT
Compression and cold therapy used separately have shown to reduce negative effects of tissue damage. The combining compression and cold therapy (cryocompression) as a single recovery modality has yet to be fully examined. To examine the effects of cryocompression on recovery following a bout of heavy resistance exercise, recreationally resistance trained men (n =16) were recruited, matched, and randomly assigned to either a cryocompression group (CRC) or control group (CON). Testing was performed before and then immediately after exercise, 60 minutes, 24 hours, and 48 hours after a heavy resistance exercise workout (barbell back squats for 4 sets of 6 reps at 80% 1RM, 90 sec rest between sets, stiff legged deadlifts for 4 sets of 8 reps at 1.0 X body mass with 60 sec rest between sets, 4 sets of 10 eccentric Nordic hamstring curls, 45 sec rest between sets). The CRC group used the CRC system for 20-mins of cryocompression treatment immediately after exercise, 24 hours, and 48 hours after exercise. CON sat quietly for 20-mins at the same time points. Muscle damage [creatine kinase], soreness (visual analog scale, 0-100), pain (McGill Pain Q, 0-5), fatigue, sleep quality, and jump power were significantly (p < 0.05) improved for CRC compared to CON at 24 and 48 hours after exercise. Pain was also significantly lower for CRC compared to CON at 60-mins post exercise. These findings show that cryocompression can enhance recovery and performance following a heavy resistance exercise workout.
ABSTRACT
The rapid pace of bacterial evolution enables organisms to adapt to the laboratory environment with repeated passage and thus diverge from naturally-occurring environmental ("wild") strains. Distinguishing wild and laboratory strains is clearly important for biodefense and bioforensics; however, DNA sequence data alone has thus far not provided a clear signature, perhaps due to lack of understanding of how diverse genome changes lead to convergent phenotypes, difficulty in detecting certain types of mutations, or perhaps because some adaptive modifications are epigenetic. Monitoring protein abundance, a molecular measure of phenotype, can overcome some of these difficulties. We have assembled a collection of Yersinia pestis proteomics datasets from our own published and unpublished work, and from a proteomics data archive, and demonstrated that protein abundance data can clearly distinguish laboratory-adapted from wild. We developed a lasso logistic regression classifier that uses binary (presence/absence) or quantitative protein abundance measures to predict whether a sample is laboratory-adapted or wild that proved to be ~98% accurate, as judged by replicated 10-fold cross-validation. Protein features selected by the classifier accord well with our previous study of laboratory adaptation in Y. pestis. The input data was derived from a variety of unrelated experiments and contained significant confounding variables. We show that the classifier is robust with respect to these variables. The methodology is able to discover signatures for laboratory facility and culture medium that are largely independent of the signature of laboratory adaptation. Going beyond our previous laboratory evolution study, this work suggests that proteomic differences between laboratory-adapted and wild Y. pestis are general, potentially pointing to a process that could apply to other species as well. Additionally, we show that proteomics datasets (even archived data collected for different purposes) contain the information necessary to distinguish wild and laboratory samples. This work has clear applications in biomarker detection as well as biodefense.
Subject(s)
Adaptation, Physiological , Bacterial Proteins/metabolism , Plague/microbiology , Yersinia pestis/metabolism , Bacteriological Techniques , Environmental Microbiology , Humans , Logistic Models , Phenotype , Plague/diagnosis , Proteome/metabolism , Proteomics/methods , Species Specificity , Yersinia pestis/classification , Yersinia pestis/geneticsABSTRACT
GOALS: This study aims to examine the effects of raising the reporting age for benign endometrial cells (BEC) on Papanicolaou (Pap) tests according to the 2014 3rd edition of the Bethesda System for Cervical Cytology, as well as the sequelae of the 2012 American Society of Colposcopy and Cervical Pathology (ASCCP) guidelines recommending endometrial asessment only for postmenopausal or symptomatic premenopausal women. PROCEDURES: We retrospectively examined clinical and histologic data from 4438 women aged ≥40 with BEC on Pap tests, of whom 608 (14%) were biopsied. RESULTS: Fifty-three (8.7%) histologic abnormalities were discovered upon biopsy. There was no significant difference (p=0.52) in abnormalities found between premenopausal women aged ≥40 and premenopausal women aged ≥45. Furthermore, there were no high-grade cancers in women between ages 40-44. There were also 3 high-grade cancers in patients aged 46, 46, and 49. Each of these women was asymptomatic and premenopausal. CONCLUSION: Our results affirm the raising of the reporting age of BEC on Pap tests from 40 to 45 in our patient population. Because there were 3 asymptomatic, premenopausal patients with high-grade cancers in our 45-49 age group, we cannot completely adhere to the ASCCP guidelines nor can we advocate raising the reporting age further to 50. Other laboratories must review their own follow-up data to validate appropriate reporting criteria for BEC for their patients.
Subject(s)
Endometrial Neoplasms/pathology , Endometrium/pathology , Papanicolaou Test , Adult , Age Factors , Aged , Aged, 80 and over , Female , Humans , Middle Aged , Postmenopause , Practice Guidelines as Topic , Uterine Diseases/pathology , Vaginal SmearsABSTRACT
Counterpulsation devices (CPDs) require an accurate, reliable electrocardiogram (ECG) waveform for triggering inflation and deflation. Surface electrodes are for short-term use, and transvenous/epicardial leads require invasive implant procedure. A subcutaneous ECG lead configuration was developed as an alternative approach for long-term use with timing mechanical circulatory support (MCS) devices. In this study, efficacy testing was completed by simultaneously recording ECG waveforms from clinical-grade epicardial (control) and subcutaneous (test) leads in chronic ischemic heart failure calves implanted with CPD for up to 30 days. Sensitivity and specificity of CPD triggering by R-wave detection was quantified for each lead configuration. The subcutaneous leads provided 98.9% positive predictive value and 98.9% sensitivity compared to the epicardial ECG leads. Lead migration (n = 1) and fracture (n = 1) were observed in only 2 of 40 implanted leads, without adversely impacting triggering efficacy due to lead redundancy. These findings demonstrate the efficacy of subcutaneous ECG leads for long-term CPD timing and potential use as an alternative method for MCS device timing.
Subject(s)
Counterpulsation , Electrocardiography , Heart Failure/therapy , Animals , Cattle , Counterpulsation/instrumentation , Electrocardiography/methods , Heart Failure/physiopathology , MaleABSTRACT
BACKGROUND: Cardiac rhythm abnormalities are a leading cause of morbidity and mortality in developed countries. Loss-of-function variants in the ANK2 gene can cause a variety of cardiac rhythm abnormalities including sinus node dysfunction, atrial fibrillation and ventricular arrhythmias (called the "ankyrin-B syndrome"). ANK2 encodes ankyrin-B, a molecule critical for the membrane targeting of key cardiac ion channels, transporters, and signalling proteins. METHODS AND RESULTS: Here, we describe a family with a reciprocal chromosomal translocation between chromosomes 4q25 and 9q26 that transects the ANK2 gene on chromosome 4 resulting in loss-of-function of ankyrin-B. Select family members with ankyrin-B haploinsufficiency due to the translocation displayed clinical features of ankyrin-B syndrome. Furthermore, evaluation of primary lymphoblasts from a carrier of the translocation showed altered levels of ankyrin-B as well as a reduced expression of downstream ankyrin-binding partners. CONCLUSIONS: Thus, our data conclude that, similar to previously described ANK2 loss-of-function "point mutations", large chromosomal translocations resulting in ANK2 haploinsufficiency are sufficient to cause the human cardiac ankyrin-B syndrome. The unexpected ascertainment of ANK2 dysfunction via the discovery of a chromosomal translocation in this family, the determination of the familial phenotype, as well as the complexities in formulating screening and treatment strategies are discussed.
Subject(s)
Ankyrins/genetics , Arrhythmias, Cardiac/genetics , Chromosomes, Human, Pair 4/genetics , Chromosomes, Human, Pair 9/genetics , Haploinsufficiency , Translocation, Genetic , Abnormalities, Multiple/genetics , Abnormalities, Multiple/physiopathology , Adult , Arrhythmias, Cardiac/physiopathology , Family , Female , Fetal Diseases/genetics , Fetal Diseases/physiopathology , Humans , Male , PregnancyABSTRACT
Ensuring data quality and proper instrument functionality is a prerequisite for scientific investigation. Manual quality assurance is time-consuming and subjective. Metrics for describing liquid chromatography mass spectrometry (LC-MS) data have been developed; however, the wide variety of LC-MS instruments and configurations precludes applying a simple cutoff. Using 1150 manually classified quality control (QC) data sets, we trained logistic regression classification models to predict whether a data set is in or out of control. Model parameters were optimized by minimizing a loss function that accounts for the trade-off between false positive and false negative errors. The classifier models detected bad data sets with high sensitivity while maintaining high specificity. Moreover, the composite classifier was dramatically more specific than single metrics. Finally, we evaluated the performance of the classifier on a separate validation set where it performed comparably to the results for the testing/training data sets. By presenting the methods and software used to create the classifier, other groups can create a classifier for their specific QC regimen, which is highly variable lab-to-lab. In total, this manuscript presents 3400 LC-MS data sets for the same QC sample (whole cell lysate of Shewanella oneidensis), deposited to the ProteomeXchange with identifiers PXD000320-PXD000324.
Subject(s)
Chromatography, Liquid/methods , Chromatography, Liquid/standards , Mass Spectrometry/methods , Mass Spectrometry/standards , Models, Statistical , Quality Control , Reproducibility of Results , Research DesignABSTRACT
Dimethyl methylphosphonate (DMMP) was used as a chemical threat agent (CTA) simulant for a first look at the effects of real-world factors on the recovery and exploitation of a CTA's impurity profile for source matching. Four stocks of DMMP having different impurity profiles were disseminated as aerosols onto cotton, painted wall board, and nylon coupons according to a thorough experimental design. The DMMP-exposed coupons were then solvent extracted and analyzed for DMMP impurities by comprehensive 2D gas chromatography/mass spectrometry (GC×GC/MS). The similarities between the coupon DMMP impurity profiles and the known (reference) DMMP profiles were measured by dot products of the coupon profiles and known profiles and by score values obtained from principal component analysis. One stock, with a high impurity-profile selectivity value of 0.9 out of 1, had 100% of its respective coupons correctly classified and no false positives from other coupons. Coupons from the other three stocks with low selectivity values (0.0073, 0.012, and 0.018) could not be sufficiently distinguished from one another for reliable matching to their respective stocks. The results from this work support that: (1) extraction solvents, if not appropriately selected, can have some of the same impurities present in a CTA reducing a CTA's useable impurity profile, (2) low selectivity among a CTA's known impurity profiles will likely make definitive source matching impossible in some real-world conditions, (3) no detrimental chemical-matrix interference was encountered during the analysis of actual office media, (4) a short elapsed time between release and sample storage is advantageous for the recovery of the impurity profile because it minimizes volatilization of forensic impurities, and (5) forensic impurity profiles weighted toward higher volatility impurities are more likely to be altered by volatilization following CTA exposure.
Subject(s)
Chemical Warfare Agents/analysis , Environmental Monitoring/methods , Environmental Pollutants/analysis , Forensic Sciences/methods , Chemical Terrorism , Chemical Warfare Agents/chemistry , Cotton Fiber , Environmental Pollutants/chemistry , Gas Chromatography-Mass Spectrometry , Nylons/chemistry , Organophosphorus Compounds/analysis , Organophosphorus Compounds/chemistryABSTRACT
In an effort to validate and demonstrate response and recovery sampling approaches and technologies, the U.S. Department of Homeland Security (DHS), along with several other agencies, have simulated a biothreat agent release within a facility at Idaho National Laboratory (INL) on two separate occasions in the fall of 2007 and the fall of 2008. Because these events constitute only two realizations of many possible scenarios, increased understanding of sampling strategies can be obtained by virtually examining a wide variety of release and dispersion scenarios using computer simulations. This research effort demonstrates the use of two software tools, CONTAM, developed by the National Institute of Standards and Technology (NIST), and Visual Sample Plan (VSP), developed by Pacific Northwest National Laboratory (PNNL). The CONTAM modeling software was used to virtually contaminate a model of the INL test building under various release and dissemination scenarios as well as a range of building design and operation parameters. The results of these CONTAM simulations were then used to investigate the relevance and performance of various sampling strategies using VSP. One of the fundamental outcomes of this project was the demonstration of how CONTAM and VSP can be used together to effectively develop sampling plans to support the various stages of response to an airborne chemical, biological, radiological, or nuclear event. Following such an event (or prior to an event), incident details and the conceptual site model could be used to create an ensemble of CONTAM simulations which model contaminant dispersion within a building. These predictions could then be used to identify priority area zones within the building and then sampling designs and strategies could be developed based on those zones.
ABSTRACT
We consider the monitoring of surgical outcomes, where each patient has a different risk of post-operative mortality due to risk factors that exist prior to the surgery. We propose a risk-adjusted (RA) survival time CUSUM chart (RAST CUSUM) for monitoring a continuous, time-to-event variable that may be right-censored. Risk adjustment is accomplished using accelerated failure time regression models. We compare the average run length performance of the RAST CUSUM chart with the RA Bernoulli CUSUM chart using data from cardiac surgeries to motivate the details of the comparison. The comparisons show that the RAST CUSUM chart is more efficient at detecting a sudden increase in the odds of mortality than the RA Bernoulli CUSUM chart, especially when the fraction of censored observations is relatively low or when a small increase in the odds of mortality occurs. We also discuss the impact of the amount of training data used to estimate chart parameters as well as the implementation of the RAST CUSUM chart during prospective monitoring.
Subject(s)
Survival Analysis , Biometry , Cardiovascular Surgical Procedures/mortality , Databases, Factual , Humans , Likelihood Functions , Logistic Models , Models, Statistical , Postoperative Complications/mortality , Risk FactorsABSTRACT
A number of methods have been proposed for detecting an increase in the incidence rate of a rare health event, such as a congenital malformation. Among these are the sets method, two modifications of the sets method, and the CUSUM method based on the Poisson distribution. We consider the situation where data are observed as a sequence of Bernoulli trials and propose the Bernoulli CUSUM chart as a desirable method for the surveillance of rare health events. We compared the performance of the sets method and its modifications with that of the Bernoulli CUSUM chart under a wide variety of circumstances. Chart design parameters were chosen to satisfy a minimax criteria. We used the steady-state average run length to measure chart performance instead of the average run length (ARL), which was used in nearly all previous comparisons involving the sets method or its modifications. Except in a very few instances, we found that the Bernoulli CUSUM chart has better steady-state ARL performance than the sets method and its modifications for the extensive number of cases considered. Thus, we recommend the use of the Bernoulli CUSUM chart to monitor small incidence rates and provide practical advice for its implementation.