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result(s) for
"Bradley, M. Scott"
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Highly efficient resonant coupling of optical excitations in hybrid organic/inorganic semiconductor nanostructures
by
Tischler, Jonathan R.
,
Atay, Tolga
,
Nurmikko, A. V.
in
Absorption
,
Aggregates
,
Chemistry and Materials Science
2007
The integration of organic and inorganic semiconductors on the nanoscale offers the possibility of developing new photonic devices that combine the best features of these two distinct classes of material. Such devices could, for example, benefit from the large oscillator strengths found in organic materials and the nonlinear optical properties of inorganic species. Here we describe a novel hybrid organic/inorganic nanocomposite in which alternating monolayers of J-aggregates of cyanine dye and crystalline semiconductor quantum dots are grown by a layer-by-layer self-assembly technique. We demonstrate near-field photon-mediated coupling of vastly dissimilar optical excitations in the two materials that can reach efficiencies of up to 98% at room temperature. By varying the size of the quantum dots and thus tuning their optical resonance for absorption and emission, we also show how the ability of J-aggregates to harvest light can be harnessed to increase the effective absorption cross section of the quantum dots by up to a factor of ten. Combining organic and inorganic semiconductors in this way could lead to novel nanoscale designs for light-emitting, photovoltaic and sensor applications
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Journal Article
Outcomes in Primary Repair of Truncus Arteriosus with Significant Truncal Valve Insufficiency: A Systematic Review and Meta-analysis
by
Korte, Jeffrey E.
,
Brennan, Emily
,
Bradley, Scott M.
in
Analysis
,
Cardiac Surgery
,
Cardiology
2023
Data regarding the effect of significant TVI on outcomes after truncus arteriosus (TA) repair are limited. The aim of this meta-analysis was to summarize outcomes among patients aged ≤ 24 months undergoing TA repair with at least moderate TVI. A systematic literature search was conducted in PubMed, Scopus, and CINAHL Complete from database inception through June 1, 2022. Studies reporting outcomes of TA repair in patients with moderate or greater TVI were included. Studies reporting outcomes only for patients aged > 24 months were excluded. The primary outcome was overall mortality, and secondary outcomes included early mortality and truncal valve reoperation. Random-effects models were used to estimate pooled effects. Assessment for bias was performed using funnel plots and Egger’s tests. Twenty-two single-center observational studies were included for analysis, representing 1,172 patients. Of these, 232 (19.8%) had moderate or greater TVI. Meta-analysis demonstrated a pooled overall mortality of 28.0% after TA repair among patients with significant TVI with a relative risk of 1.70 (95% CI [1.27–2.28],
p
< 0.001) compared to patients without TVI. Significant TVI was also significantly associated with an increased risk for early mortality (RR 2.04; 95% CI [1.36–3.06],
p
< 0.001) and truncal valve reoperation (RR 3.90; 95% CI [1.40–10.90],
p
= 0.010). Moderate or greater TVI before TA repair is associated with an increased risk for mortality and truncal valve reoperation. Management of TVI in patients remains a challenging clinical problem. Further investigation is needed to assess the risk of concomitant truncal valve surgery with TA repair in this population.
Journal Article
Timing of surgical repair and resource utilisation in infants with complete atrioventricular septal defect
by
Chowdhury, Shahryar M.
,
Zyblewski, Sinai C.
,
Lucas, Jon F.
in
Cardiac Surgical Procedures
,
Cohort Studies
,
Heart Septal Defects - surgery
2023
Variation exists in the timing of surgery for balanced complete atrioventricular septal defect repair. We sought to explore associations between timing of repair and resource utilisation and clinical outcomes in the first year of life.
In this retrospective single-centre cohort study, we included patients who underwent complete atrioventricular septal defect repair between 2005 and 2019. Patients with left or right ventricular outflow tract obstruction and major non-cardiac comorbidities (except trisomy 21) were excluded. The primary outcome was days alive and out of the hospital in the first year of life.
Included were 79 infants, divided into tertiles based on age at surgery (1st = 46 to 137 days, 2nd = 140 - 176 days, 3rd = 178 - 316 days). There were no significant differences among age tertiles for days alive and out of the hospital in the first year of life by univariable analysis (tertile 1, median 351 days; tertile 2, 348 days; tertile 3, 354 days; p = 0.22). No patients died. Fewer post-operative ICU days were used in the oldest tertile relative to the youngest, but days of mechanical ventilation and hospitalisation were similar. Clinical outcomes after repair and resource utilisation in the first year of life were similar for unplanned cardiac reinterventions, outpatient cardiology clinic visits, and weight-for-age z-score at 1 year.
Age at complete atrioventricular septal defect repair is not associated with important differences in clinical outcomes or resource utilisation in the first year of life.
Journal Article
Comparison of Maximum Vasoactive Inotropic Score and Low Cardiac Output Syndrome As Markers of Early Postoperative Outcomes After Neonatal Cardiac Surgery
by
Bradley, Scott M
,
Scheurer, Mark A
,
Zyblewski, Sinai C
in
Cardiac arrest
,
Cardiac arrhythmia
,
Dopamine
2012
Low cardiac output syndrome (LCOS) and maximum vasoactive inotropic score (VIS) have been used as surrogate markers for early postoperative outcomes in pediatric cardiac surgery. The objective of this study was to determine the associations between LCOS and maximum VIS with clinical outcomes in neonatal cardiac surgery. This was a secondary retrospective analysis of a prospective randomized trial, and the setting was a pediatric cardiac intensive care unit in a tertiary care children’s hospital. Neonates (n = 76) undergoing corrective or palliative cardiac operations requiring cardiopulmonary bypass were prospectively enrolled. LCOS was defined by a standardized clinical criteria. VIS values were calculated by a standard formula during the first 36 postoperative hours, and the maximum score was recorded. Postoperative outcomes included hospital mortality, duration of mechanical ventilation, intensive care unit (ICU) and hospital lengths of stay (LOS), as well as total hospital charges. At surgery, the median age was 7 days and weight was 3.2 kg. LCOS occurred in 32 of 76 (42%) subjects. Median maximum VIS was 15 (range 5–33). LCOS was not associated with duration of mechanical ventilation, ICU LOS, hospital LOS, and hospital charges. Greater VIS was moderately associated with a longer duration of mechanical ventilation (p = 0.001, r = 0.36), longer ICU LOS (p = 0.02, r = 0.27), and greater total hospital costs (p = 0.05, r = 0.22) but not hospital LOS (p = 0.52). LCOS was not associated with early postoperative outcomes. Maximum VIS has only modest correlation with duration of mechanical ventilation, ICU LOS, and total hospital charges.
Journal Article
Utility of computed tomographic angiography in the pre-operative planning for initial and repeat congenital cardiovascular surgery
by
Ellis, Alexander R.
,
Mulvihill, Denise
,
Hlavacek, Anthony M.
in
Adolescent
,
alternative imaging modality
,
Angiography - methods
2010
To investigate the utility of computed tomographic angiography as an adjunctive imaging modality before congenital cardiac surgery.
We evaluated 33 patients who underwent a pre-operative computed tomographic angiogram. They were classified according to the anatomic site of repair. Post-operatively, the surgeon completed a questionnaire assessing the utility of the study.
Computed tomographic angiography was found to be either \"essential\" or \"very useful\" for pre-operative planning in 94% of the patients. Specifically, the scan was consistently useful for procedures involving the aorta (14/15, 93%) or the pulmonary veins (4/4, 100%) and obviated pre-operative catheterisations in 14 patients (42%). Furthermore, when compared with other diagnostic groups, computed tomographic angiography determined the need for peripheral cannulation in patients undergoing re-operations (6/7; 86%, p = 0.02).
Computed tomographic angiography was found to be useful in the pre-operative planning of virtually all patients undergoing repair of congenital cardiac malformations, regardless of diagnosis. Specifically, the studies were essential in select populations, such aortic arch or pulmonary vein repairs, and helped to determine cannulation sites for repeat operations while significantly reducing the need for invasive imaging.
Journal Article
Pulmonary arteriovenous malformations after the superior cavopulmonary shunt: mechanisms and clinical implications
by
Bradley, Scott M
,
Mukherjee, Rupak
,
Stroud, Robert E
in
angiogenesis
,
cavopulmonary connection
,
congenital heart disease
2014
Children with functional single ventricle heart disease are commonly palliated down a staged clinical pathway toward a Fontan completion procedure (total cavopulmonary connection). The Fontan physiology is fraught with long-term complications associated with lower body systemic venous hypertension, eventually resulting in significant morbidity and mortality. The bidirectional Glenn shunt or superior cavopulmonary connection (SCPC) is commonly the transitional stage in single ventricle surgical management and provides excellent palliation. Some studies have demonstrated lower morbidity and mortality with the SCPC when compared with the Fontan. Unfortunately the durability of the SCPC is significantly limited by the development of pulmonary arteriovenous malformations (PAVMs) which have been commonly attributed to the absence of hepatic venous blood flow and the lack of pulsatile flow to the affected lungs. Abnormal angiogenesis has been suggested as a final common pathway to PAVM development. Understanding these fundamental mechanisms through the investigation of angiogenic pathways associated with the pathogenesis of PAVMs would help to develop medical therapies that could prevent or reverse this complication following SCPC. Such therapies could improve the longevity of the SCPC, potentially eliminate or significantly postpone the Fontan completion with its associated complications, and improve long-term survival in children with single ventricle disease.
Journal Article
Does a ventriculotomy have deleterious effects following palliation in the Norwood procedure using a shunt placed from the right ventricle to the pulmonary arteries?
by
Laudito, Antonio
,
Bradley, Scott M.
,
Shirali, Girish S.
in
Anastomosis, Surgical
,
Blood pressure
,
Cardiac Catheterization
2007
Introduction: A recent modification to the Norwood procedure involving a shunt placed directly from the right ventricle to the pulmonary arteries may improve postoperative haemodynamics. Concerns remain, however, about the potential problems produced by the required ventriculotomy. Methods: We compared 76 patients with hypoplastic left heart syndrome who underwent the Norwood procedure, 35 receiving a modified Blalock-Taussig shunt and the remaining 41 a shunt placed directly from the right ventricle to the pulmonary arteries. We reviewed their subsequent progress through the second stage of palliation. A single observer graded right ventricular function, and the severity of tricuspid regurgitation, based on blinded review of the most recent echocardiograms prior to the second stage of palliation. Results: At the time of catheterization prior to the second stage, patients with a shunt placed from the right ventricle to the pulmonary arteries, rather than a modified Blalock-Taussig shunt, had higher arterial diastolic blood pressure, at 44 versus 40 millimetres of mercury, p equal to 0.02, lower ventricular end diastolic pressures, at 8 versus 11 millimetres of mercury, p equal to 0.0002, and larger pulmonary arteries as judged using the Nakata index, at 270 versus 188 millimetres squared per metres squared, p equal to 0.009. There was no difference in qualitative ventricular systolic function or tricuspid regurgitation between groups. No differences were found between groups during the hospitalization following the second stage of palliation. A trend towards improved survival to the second stage was seen following the construction of a shunt from the right ventricle to the pulmonary arteries. Conclusions: Construction of a shunt from the right ventricle to the pulmonary arteries is associated with lower right ventricular end diastolic pressures, larger pulmonary arterial size, and higher systemic arterial diastolic pressures. No apparent deleterious effects of the right ventriculotomy were observed in terms of qualitative ventricular systolic function or tricuspid regurgitation.
Journal Article
The prevalence of attention-deficit/hyperactivity disorder following neonatal aortic arch repair
by
Ellis, Charles
,
Atz, Andrew M.
,
Sistino, Joseph J.
in
Adolescent
,
Aorta, Thoracic - surgery
,
Aortic Diseases - complications
2015
Objective: We sought to determine the prevalence of attention-deficit/hyperactivity disorder in a population of children who underwent neonatal heart surgery involving repair of the aortic arch for Norwood Stage I, interrupted aortic arch, and combined repair of aortic coarctation with ventricular septal defect. Methods: Children between the ages of 5 and 16 were surveyed using the ADHD-IV and the Child Heath Questionnaire-50. Classification as attention-deficit/hyperactivity disorder was defined for this study as either a parent-reported diagnosis of attention-deficit/hyperactivity disorder or ADHD-IV inattention score of ⩾93 percentile. Results: Of the 134 surveys, 57 (43%) were returned completed. A total of 25 (44%) children either had a diagnosis of attention-deficit/hyperactivity disorder and/or ADHD-IV inattention score ⩾93 percentile. Eleven of the 13 (85%) children with interrupted aortic arch, 3 of the 7 (42.9%) children with combined coarctation/ventricular septal defect repair, and 9 of the 33 (27.3%) children with hypoplastic left-heart syndrome were classified as having attention-deficit/hyperactivity disorder. Only 7 of the 25 (28%) children received medical treatment for this condition. Quality of life indicators in the Child Heath Questionnaire-50 Questionnaire were highly correlated with the ADHD-IV scores. Conclusion: The risks for the development of attention-deficit/hyperactivity disorder are multifactorial but are significantly increased in this post-surgical population. This study revealed a low treatment rate for attention-deficit/hyperactivity disorder, and a significant impact on the quality of life in these children.
Journal Article
Reduction in Postoperative High-Density Lipoprotein Cholesterol Levels in Children Undergoing the Fontan Operation
2012
Despite the emerging relevance of high-density lipoprotein (HDL) in the inflammatory cascade and vascular barrier integrity, HDL levels in children undergoing cardiac surgery are unexplored. As a measure of HDL levels, the HDL-cholesterol (HDL-C) in single-ventricle patients was quantified before and after the Fontan operation, and it was determined whether relationships existed between the duration and the type of postoperative pleural effusions. The study prospectively enrolled 12 children undergoing the Fontan operation. Plasma HDL-C levels were measured before and after cardiopulmonary bypass. The outcome variables of interest were the duration and type of chest tube drainage (chylous vs. nonchylous). The Kendall rank correlation coefficient and the Wilcoxon rank sum test were used. There were 11 complete observations. The median preoperative HDL-C level for all the subjects was 30 mg/dl (range, 24–53 mg/dl), and the median postcardiopulmonary bypass level was 21 mg/dl (range, 14–46 mg/dl) (p = 0.004). There was a tendency toward a moderate inverse correlation (–0.42) between the postcardiopulmonary bypass HDL-C level and the duration of chest tube drainage, but the result was not statistically significant (p = 0.07). In the chylous effusion group, the median postcardiopulmonary bypass HDL-C tended to be lower (16 vs. 23 mg/dl; p = 0.09). After the Fontan operation, the plasma HDL-C levels in children are significantly reduced. It is reasonable to conclude that the reduction in HDL-C reflects reduced plasma levels of HDL particles, which may have pertinent implications in postoperative pleural effusions given the antiinflammatory and endothelial barrier functions of HDL.
Journal Article