Pure-phase CuWO4 photoanodes with 200 nm thickness were produced by spin-casting sol–gel precursors to evaluate their performance as photoelectrodes for water oxidation. The stability of CuWO4 in ...potassium phosphate (KPi) and potassium borate (KBi) buffers was evaluated as a function of pH and irradiance. CuWO4 photoanodes demonstrate higher stability at pH 3 and 5 in a 0.1 M KPi buffer and are significantly more stable over a 12 h period of illumination in a 0.1 M KBi buffer at pH 7 (∼75 μA/cm2 photocurrent at 1.23 V vs RHE (reversible hydrogen electrode) and 1 sun illumination) than in a 0.1 M KPi buffer at pH 7. The onset of photoelectrochemical water oxidation and electrochemical O2 reduction is dictated by Cu(3d x 2–y 2 ) states that reside at 0.4 V vs RHE, determined by linear sweep voltammetry. The onset for water oxidation is hindered by a large charge-transfer resistance, as high as 4.6 kΩ at 1 V vs RHE. Nevertheless, CuWO4 photoanodes show nearly quantitative faradic efficiency for water oxidation, even in the presence of chloride, an improvement over the binary oxide WO3.
Electrodeposited thin films composed of CuWO4–WO3 oxidize water under AM 1.5G irradiation with no electrical bias and simultaneous reduction of Fe(CN)63– at a Pt-mesh auxiliary electrode with a ...faradaic efficiency of >85%. The quantum efficiency and apparent quantum yield are 7% (at 400 nm) and 0.038%, respectively, in a representative film. Although low, the photoanode is stable, maintaining its steady-state current density (17 μA/cm2) over a 2.5 h illumination period. Through full photoelectrochemical characterization, we identify the specific drawbacks in our material and propose solutions.
Background
The arterial switch operation (ASO) is the preferred surgical procedure used to correct dextro-transposition of the great arteries. A known complication of the ASO is branch pulmonary ...arteries (PAs) stenosis, which may require reintervention. Our goal is to determine the frequency of reintervention after the ASO and any factors associated with reintervention.
Methods
This was a single center, retrospective study of infants who underwent the ASO from June 6, 2011 to February 21, 2021. The primary outcome was the prevalence of reintervention on the PAs following the ASO.
Results
Sixty-eight infants were analyzed; 9 (13%) patients had 10 reinterventions. The mean age at time of the ASO was 6.52 ± 6.63 days; weight was 3.34 ± 0.57 kg. Those with a reintervention had a longer bypass time (P = .047). Mean age at reintervention was 0.80 ± 0.72 years; mean time from the ASO to reintervention was 0.799 ± 0.717 years. Six surgical procedures, two stent placements, and four balloon angioplasties were performed on a total of 13 branch PAs. There was no increased risk for reintervention on the right versus left PA. After reintervention, there was an improvement in the minimal PA diameter and echo gradient. There were no adverse events or mortality related to the reintervention. Mean follow-up was 6.17 ± 2.94 years.
Conclusion
The prevalence of branch PA reintervention following the ASO in our cohort was 13%. There is an association between longer cardiopulmonary bypass time and reintervention. After reintervention, there was an increase in PA diameter and a decrease in echo gradient.
While the Norwood operation is the most common palliative surgery for neonates with hypoplastic left heart syndrome (HLHS), initial hybrid strategy aiming to restrict pulmonary blood flow and ...maintain systemic output is necessary when Norwood is contraindicated or at high risk. The traditional mainstay of initial hybrid palliation is surgical pulmonary artery branch banding (PABB) plus interventional ductal stenting. We present a case of a transcatheter approach for pulmonary flow restriction (PFR) that was accomplished by modifying a Medtronic microvascular plug (MVP)™. The patient is a 2.4 kg neonate diagnosed with HLHS, dysplastic tricuspid and pulmonary valves with pulmonary stenosis, tricuspid stenosis, and regurgitation. He was not considered a candidate for surgical intervention. He started developing sequelae of unbalanced pulmonary and systemic blood flow; therefore, he underwent placement of transcatheter PFR as alternative to PABB. He underwent successful orthotopic heart transplant 104 days after index procedure. This case demonstrates the significant complexity that can occur in patients with HLHS and abnormal right sided valves. Additionally, it is another example that transcatheter branch pulmonary artery flow restriction can be a safe and feasible alternative to PABB as initial palliation strategy. It may benefit patients in whom primary Norwood procedure would have increased risks or who will undergo primary transplant.
Rett syndrome is an X‐linked neurodevelopmental disorder caused by mutation of Mecp2 gene and primarily affects females. Glial cell dysfunction has been implicated in in Rett syndrome (RTT) both in ...patients and in mouse models of this disorder and can affect synaptogenesis, glial metabolism and inflammation. Here we assessed whether treatment of adult (5–6 months old) symptomatic Mecp2‐heterozygous female mice with N‐acetyl cysteine conjugated to dendrimer (D‐NAC), which is known to target glia and modulate inflammation and oxidative injury, results in improved behavioral phenotype, sleep and glial inflammatory profile. We show that unbiased global metabolomic analysis of the hippocampus and striatum in adult Mecp2‐heterozygous mice demonstrates significant differences in lipid metabolism associated with neuroinflammation, providing the rationale for targeting glial inflammation in this model. Our results demonstrate that treatment with D‐NAC (10 mg/kg NAC) once weekly is more efficacious than equivalently dosed free NAC in improving the gross neurobehavioral phenotype in symptomatic Mecp2‐heterozygous female mice. We also show that D‐NAC therapy is significantly better than saline in ameliorating several aspects of the abnormal phenotype including paw clench, mobility, fear memory, REM sleep and epileptiform activity burden. Systemic D‐NAC significantly improves microglial proinflammatory cytokine production and is associated with improvements in several aspects of the phenotype including paw clench, mobility, fear memory, and REM sleep, and epileptiform activity burden in comparison to saline‐treated Mecp2‐hetereozygous mice. Systemic glial‐targeted delivery of D‐NAC after symptom onset in an older clinically relevant Rett syndrome model shows promise in improving neurobehavioral impairments along with sleep pattern and epileptiform activity burden. These findings argue for the translational value of this approach for treatment of patients with Rett Syndrome.
Rett syndrome is a neurodevelopmental disorder primarily affecting females, caused by mutations in the Mecp2 gene. Glial cell dysfunction and inflammation contribute to the pathogenesis of this disorder. In this study, we investigated the therapeutic potential of a targeted treatment, N‐acetyl cysteine conjugated to dendrimer (D‐NAC), in symptomatic Mecp2‐heterozygous female mice. We found that D‐NAC treatment significantly improved the neurobehavioral phenotype, memory, sleep patterns, and microglial inflammatory profile. This study offers valuable insights into the underlying mechanisms and therapeutic approaches for Rett syndrome, with implications for the development of novel interventions for patients affected by this debilitating condition.
Medical school assessments should foster the development of higher-order thinking skills to support clinical reasoning and a solid foundation of knowledge. Multiple-choice questions (MCQs) are ...commonly used to assess student learning, and well-written MCQs can support learner engagement in higher levels of cognitive reasoning such as application or synthesis of knowledge. Bloom’s taxonomy has been used to identify MCQs that assess students’ critical thinking skills, with evidence suggesting that higher-order MCQs support a deeper conceptual understanding of scientific process skills. Similarly, clinical practice also requires learners to develop higher-order thinking skills that include all of Bloom’s levels. Faculty question writers and examinees may approach the same material differently based on varying levels of knowledge and expertise, and these differences can influence the cognitive levels being measured by MCQs. Consequently, faculty question writers may perceive that certain MCQs require higher-order thinking skills to process the question, whereas examinees may only need to employ lower-order thinking skills to render a correct response. Likewise, seemingly lower-order questions may actually require higher-order thinking skills to respond correctly. In this Perspective, the authors describe some of the cognitive processes examinees use to respond to MCQs. The authors propose that various factors affect both the question writer and examinee’s interaction with test material and subsequent cognitive processes necessary to answer a question.
To describe the duration of time to achieve exclusive oral feeding in infants with single ventricle physiology and to identify risk factors associated with prolonged gastrostomy tube dependence.
...Single center, retrospective study of infants with single ventricle physiology. The primary outcome was duration of time required to achieve oral feeding. Transition periods were defined as exclusive oral feeding by Glenn palliation (early), by 1 year of age (mid), or after 1 year of age (late).
Seventy-eight infants were analyzed; 46 (59%) were discharged to home with a gastrostomy tube after the initial hospitalization. Overall, 39 infants (50%) achieved early transition, 14 (18%) mid, and 18 (23%) late. The group who achieved early transition had a higher percentage of preoperative oral feeding (P < .01), greater weight-for-age z score at initial discharge (P = .03), shorter initial intensive care unit duration (P < .01), shorter initial hospital length of stay (P < .01), and greater weight-for-age z score at Glenn admission (P = .02). No preoperative oral feeding (OR = 0.12, P = .02) and greater number of cardiac medications at initial discharge (OR = 3.8, P = .03) were associated with failure to achieve early transition. No preoperative oral feeding (OR = 0.09, P = .01) and longer initial intensive care unit duration (OR = 1.1, P = .03) were associated with failure to achieve mid transition.
Preoperative oral feeding may potentially be a modifiable factor to help improve early transition to oral feeding.
PDF
