Analysis and Implementation of the Maximum Likelihood Expectation Maximization Algorithm for FIND

This thesis presents an organized explanation and breakdown of the Maximum Likelihood Expectation Maximization image reconstruction algorithm. This background research was used to develop a means of implementing the algorithm into the imaging code for UNH\u27s Field Deployable Imaging Neutron Detector to improve its ability to resolve complex neutron sources. This thesis provides an overview for this implementation scheme, and include the results of a couple of reconstruction tests for the algorithm. A discussion is given on the current state of the algorithm and its integration with the neutron detector system, and suggestions are given for how the work and results of this project could be continued and expanded upon

Prolonged toxicity in a 2-year-old after accidental ingestion of aripiprazole.

Aripiprazole (Abilify), or 7-{4-[4-(2,3-dichlorophenyl)-1-piperazinyl]butyloxy}-3,4-dihydro-2(1H)-quinolone, is a novel atypical antipsychotic possessing a long half-life. Although not a Food and Drug Administration-approved indication, low-dose aripiprazole is used to treat pediatric psychiatric conditions. Data regarding toxicity of low-dose aripiprazole ingestions in children are limited. We report the case of an accidental ingestion of two 5-mg aripiprazole tablets by a 2-year-old girl with a measured drug level of 160 ng/mL approximately 34 hours after ingestion. She exhibited marked lethargy, tremor, and tachycardia persisting over 72 hours. Emergency physicians, pediatricians, and psychiatrists should be aware of the potential for significant and prolonged toxicity in children even with relatively small-dose aripiprazole exposures

Preexisting Depression and Ambulatory Status After Stroke: Florida-Puerto Rico Collaboration to Reduce Stroke Disparities

OBJECTIVE: Stroke is a global public health burden, and therefore it is critical to identify modifiable risk factors to reduce stroke incidence and improve outcomes. Depression is such a risk factor; however, the association between preexisting depression and stroke outcomes, such as independent ambulation, is not well studied, especially among racial-ethnic minority groups. To address this gap in the literature, effects of preexisting depression on ambulatory status at hospital discharge after stroke were evaluated among individuals participating in the racially and ethnically diverse Florida-Puerto Rico Collaboration to Reduce Stroke Disparities project. METHODS: Data were analyzed from a total of 42,031 ischemic stroke patients, who were independently ambulatory prior to their stroke, after discharge from 84 hospitals between 2014 and 2017. Preexisting depression was confirmed by medical history or antidepressant medication use. Multilevel multivariate logistic regression analyses were used to assess the association of preexisting depression with independent ambulation at hospital discharge. Effects of sex and race-ethnicity on this association were examined. RESULTS: Of 42,031 participants (mean±SD age=70.4±14.2 years; 48% were female; race-ethnicity: 16% Black, 12% Hispanic living in Florida, and 7% Hispanic living in Puerto Rico), 6,379 (15%) had preexisting depression. Compared with participants without depression, those with preexisting depression were older, were more likely to be female and non-Hispanic White, and had a greater burden of vascular risk factors or comorbid conditions. Independent ambulation at hospital discharge was less frequent among women, Black participants, and individuals with vascular risk factors or comorbid conditions. In multivariate models, preexisting depression decreased the likelihood of independent ambulation at discharge (odds ratio=0.88, 95% CI=0.81, 0.97). No interactions were found between preexisting depression and race-ethnicity or sex. CONCLUSIONS: Preexisting depression was independently associated with dependent ambulation at hospital discharge after stroke, regardless of sex and race-ethnicity. Treating depression may contribute to primary stroke prevention and could improve ambulatory status at discharge

Ten-Year Review of Antihypertensive Prescribing Practices After Stroke and the Associated Disparities From the Florida Stroke Registry

BACKGROUND: Guideline-based hypertension management is integral to the prevention of stroke. We examine trends in antihypertensive medications prescribed after stroke and assess how well a prescriber\u27s blood pressure (BP) medication choice adheres to clinical practice guidelines (BP-guideline adherence). METHODS AND RESULTS: The FSR (Florida Stroke Registry) uses statewide data prospectively collected for all acute stroke admissions. Based on established guidelines, we defined optimal BP-guideline adherence using the following hierarchy of rules: (1) use of an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker as first-line antihypertensive among diabetics; (2) use of thiazide-type diuretics or calcium channel blockers among Black patients; (3) use of beta blockers among patients with compelling cardiac indication; (4) use of thiazide, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, or calcium channel blocker class as first line in all others; (5) beta blockers should be avoided as first line unless there is a compelling cardiac indication. A total of 372 254 cases from January 2010 to March 2020 are in the FSR with a diagnosis of acute ischemic stroke, hemorrhagic stroke, transient ischemic attack, or subarachnoid hemorrhage; 265 409 with complete data were included in the final analysis. Mean age was 70±14 years; 50% were women; and index stroke subtypes were 74% acute ischemic stroke, 11% intracerebral hemorrhage, 11% transient ischemic attack, and 4% subarachnoid hemorrhage. BP-guideline adherence to each specific rule ranged from 48% to 74%, which is below quality standards of 80%, and was lower among Black patients (odds ratio, 0.7 [95% CI, 0.7-0.83]; CONCLUSIONS: This large data set demonstrates consistently low rates of BP-guideline adherence over 10 years. There is an opportunity for monitoring hypertensive management after stroke

The UTMOST pulsar timing programme II:Timing noise across the pulsar population

While pulsars possess exceptional rotational stability, large scale timing studies have revealed at least two distinct types of irregularities in their rotation: red timing noise and glitches. Using modern Bayesian techniques, we investigated the timing noise properties of 300 bright southern-sky radio pulsars that have been observed over 1.0-4.8 years by the upgraded Molonglo Observatory Synthesis Telescope (MOST). We reanalysed the spin and spin-down changes associated with nine previously reported pulsar glitches, report the discovery of three new glitches and four unusual glitch-like events in the rotational evolution of PSR J1825$-$0935. We develop a refined Bayesian framework for determining how red noise strength scales with pulsar spin frequency ($\nu$) and spin-down frequency ($\dot{\nu}$), which we apply to a sample of 280 non-recycled pulsars. With this new method and a simple power-law scaling relation, we show that red noise strength scales across the non-recycled pulsar population as $\nu^{a} |\dot{\nu}|^{b}$, where $a = -0.84^{+0.47}_{-0.49}$ and $b = 0.97^{+0.16}_{-0.19}$. This method can be easily adapted to utilise more complex, astrophysically motivated red noise models. Lastly, we highlight our timing of the double neutron star PSR J0737$-$3039, and the rediscovery of a bright radio pulsar originally found during the first Molonglo pulsar surveys with an incorrectly catalogued position.Comment: Accepted by MNRAS. 28 pages, 8 figures, 8 table

Antimicrobial use Guidelines for Treatment of Respiratory Tract Disease in Dogs and Cats: Antimicrobial Guidelines Working Group of the International Society for Companion Animal Infectious Diseases

Respiratory tract disease can be associated with primary or secondary bacterial infections in dogs and cats and is a common reason for use and potential misuse, improper use, and overuse of antimicrobials. There is a lack of comprehensive treatment guidelines such as those that are available for human medicine. Accordingly, the International Society for Companion Animal Infectious Diseases convened a Working Group of clinical microbiologists, pharmacologists, and internists to share experiences, examine scientific data, review clinical trials, and develop these guidelines to assist veterinarians in making antimicrobial treatment choices for use in the management of bacterial respiratory diseases in dogs and cats.M.R. Lappin, J. Blondeau, D. Boothe, E.B. Breitschwerdt, L. Guardabassi, D.H. Lloyd, M.G. Papich, S.C. Rankin, J.E. Sykes, J. Turnidge, and J.S. Wees

Impact of Time to Treatment on Endovascular Thrombectomy Outcomes in the Early Versus Late Treatment Time Windows

BACKGROUND: The impact of time to treatment on outcomes of endovascular thrombectomy (EVT) especially in patients presenting after 6 hours from symptom onset is not well characterized. We studied the differences in characteristics and treatment timelines of EVT-treated patients participating in the Florida Stroke Registry and aimed to characterize the extent to which time impacts EVT outcomes in the early and late time windows. METHODS: Prospectively collected data from Get With the Guidelines-Stroke hospitals participating in the Florida Stroke Registry from January 2010 to April 2020 were reviewed. Participants were EVT patients with onset-to-puncture time (OTP) of ≤24 hours and categorized into early window treated (OTP ≤6 hours) and late window treated (OTP \u3e6 and ≤24 hours). Association between OTP and favorable discharge outcomes (independent ambulation, discharge home and to acute rehabilitation facility) as well as symptomatic intracerebral hemorrhage and in-hospital mortality were examined using multilevel-multivariable analysis with generalized estimating equations. RESULTS: Among 8002 EVT patients (50.9% women; median age [±SD], 71.5 [±14.5] years; 61.7% White, 17.5% Black, and 21% Hispanic), 34.2% were treated in the late time window. Among all EVT patients, 32.4% were discharged home, 23.5% to rehabilitation facility, 33.7% ambulated independently at discharge, 5.1% had symptomatic intracerebral hemorrhage, and 9.2% died. As compared with the early window, treatment in the late window was associated with lower odds of independent ambulation (odds ratio [OR], 0.78 [0.67-0.90]) and discharge home (OR, 0.71 [0.63-0.80]). For every 60-minute increase in OTP, the odds of independent ambulation reduced by 8% (OR, 0.92 [0.87-0.97]; CONCLUSIONS: In routine practice, just over one-third of EVT-treated patients independently ambulate at discharge and only half are discharged to home/rehabilitation facility. Increased time from symptom onset to treatment is significantly associated with lower chance of independent ambulation and ability to be discharged home after EVT in the early time window

Predictors and Temporal Trends of Withdrawal of Life-Sustaining Therapy After Acute Stroke in the Florida Stroke Registry

UNLABELLED: Temporal trends and factors associated with the withdrawal of life-sustaining therapy (WLST) after acute stroke are not well determined. DESIGN: Observational study (2008-2021). SETTING: Florida Stroke Registry (152 hospitals). PATIENTS: Acute ischemic stroke (AIS), intracerebral hemorrhage (ICH), and subarachnoid hemorrhage (SAH) patients. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Importance plots were performed to generate the most predictive factors of WLST. Area under the curve (AUC) for the receiver operating curve were generated for the performance of logistic regression (LR) and random forest (RF) models. Regression analysis was applied to evaluate temporal trends. Among 309,393 AIS patients, 47,485 ICH patients, and 16,694 SAH patients; 9%, 28%, and 19% subsequently had WLST. Patients who had WLST were older (77 vs 70 yr), more women (57% vs 49%), White (76% vs 67%), with greater stroke severity on the National Institutes of Health Stroke Scale greater than or equal to 5 (29% vs 19%), more likely hospitalized in comprehensive stroke centers (52% vs 44%), had Medicare insurance (53% vs 44%), and more likely to have impaired level of consciousness (38% vs 12%). Most predictors associated with the decision to WLST in AIS were age, stroke severity, region, insurance status, center type, race, and level of consciousness (RF AUC of 0.93 and LR AUC of 0.85). Predictors in ICH included age, impaired level of consciousness, region, race, insurance status, center type, and prestroke ambulation status (RF AUC of 0.76 and LR AUC of 0.71). Factors in SAH included age, impaired level of consciousness, region, insurance status, race, and stroke center type (RF AUC of 0.82 and LR AUC of 0.72). Despite a decrease in the rates of early WLST (\u3c 2 d) and mortality, the overall rates of WLST remained stable. CONCLUSIONS: In acute hospitalized stroke patients in Florida, factors other than brain injury alone contribute to the decision to WLST. Potential predictors not measured in this study include education, culture, faith and beliefs, and patient/family and physician preferences. The overall rates of WLST have not changed in the last 2 decades