Simple Defects Research Articles

Risk assessment tool implementation in congenital heart disease associated pulmonary arterial hypertension

Abstract Background Risk assessment is recommended for patients with congenital heart disease associated pulmonary arterial hypertension (CHD-PAH). Patients in intermediate or high risk may need intensified therapies to improve their survival. Purpose To compare an abbreviated version of the risk assessment strategy proposed by the current European PH guidelines, noninvasive French model, and an abridged version of the REVEAL 2.0 risk score calculator, REVEAL Lite 2. Methods We enrolled a mixed prevalent and incident cohort of patients with CHD-PAH from 6 PAH centers from January 2006 to December 2019 (n=126). Noninvasive French model comprising WHO functional class (FC), 6-minute walk distance (6 MWD), and N-terminal pro–brain natriuretic peptide (NT-pro BNP) or BNP was used. REVEAL Lite 2 includes FC, systolic blood pressure, heart rate, 6MWD, BNP/NT-pro BNP, and estimated glomerular filtration rate. Patients were grouped into three categories according to the number of non-invasive low-risk criteria (French model) and REVEAL Lite 2 scores. Risk was calculated based on the last available assessment at 12 months' follow-up, starting from enrollment. Kaplan-Meier (KM) survival was assessed in patients in each risk group with all-cause mortality as the end point. Log-rank test was used to compare estimates. Results The mean age was 32±16 years at diagnosis. The mean follow up was 99.41±58.2 months. 32 patients had died. Most patients were Eisenmenger Syndrome (39.4%) and simple defects (19.7%). Most patients had received monotherapy (74.5%). 66.6% of patients were WHO FC I–II, 29.3% III, and 3.9% IV (Table). Both models effectively discriminated risk in our cohort (p=0.0001). Patients achieving two or more noninvasive low-risk criteria or low risk category by REVEAL Lite 2 at follow-up had a significantly reduced risk of death. Figure demonstrates KM survival curves for noninvasive French model (A) and REVEAL Lite 2 (B). 51% of patients achieved 2 or more low risk criteria at follow-up. 56% of patients were in low risk at follow-up (REVEAL lite 2). The estimated survival rate at 5 years of patients meeting 2 and more low-risk criteria at follow-up was 100% vs. 86.8% for patients meeting 1 low-risk criterion and 59.6% for patients meeting 0 low-risk criterion. The corresponding survival rate was 65% for high-risk patient, 76.2% for intermediate-risk patient, and 100% for low-risk patient (REVEAL lite 2) (p=0.0001 by log-rank test; Figure). REVEAL Lite 2 approximates noninvasive French model at discriminating among patients at low, intermediate, or high risk based on c-index. Conclusions Both noninvasive French model and REVEAL Lite 2 provide a simplified and robust method of risk assessment for CHD-PAH. This analysis also supports the value of goal-oriented treatment in CHD-PAH. Patients who have less than 2 low-risk criteria or who have not achieved low risk category at follow-up may benefit from escalation of their treatment regimen. Funding Acknowledgement Type of funding sources: None.

Eisenmenger syndrome: is it the same entity in adulthood and pediatric age?

Abstract Introduction Eisenmenger syndrome is the final clinical stage of different congenital heart diseases (CHD) associated with pulmonary arterial hypertension (PAH). Children born in recent years with CHD have benefited from advances in pediatric cardiac surgery that have modified their evolution compared to adults with the same pathologies. Purpose Our objective was to define and compare the characteristics and prognosis of the adult and pediatric population with Eisenmenger Syndrome. Methods REHAP and REHIPED are Spanish, voluntary, multicenter registries that include patients with PAH associated with CHD. REHAP started in 2007 and includes patients over 18 years of age. Patients diagnosed with PAH after this time were prospectively included, until 2020. Patients who were followed in the participating centres and diagnosed after January 1998 were retrospectively included in the registry. REHIPED started in 2009 and collects patients between 2 months and 18 years of age. Patients diagnosed with PAH after this time were prospectively included, until 2020. Patients who were followed and diagnosed after January 1998 were retrospectively included. The baseline characteristics, hemodynamic profile, treatment, and 10-year survival of the REHAP patients were compared to those included in the REHIPED. Results Eisenmenger syndrome is the main clinical group in adults (56% of patients with PAH associated with CHD enlisted in REHAP), 371 patients were included. On the other hand, Eisenmenger syndrome is the least frequent clinical group in childhood (21% of patients with PAH associated with CHD enlisted in REHIPED), 32 patients were included. Among adults, simple defects were significatively more common, whereas complex defects were more frequent in children (p 0.004). Half of the patients were in NYHA class III-IV, with no difference between groups. Adults presented greater hemodynamic severity, with higher mean pulmonary arterial pressure and greater pulmonary vascular resistance index. There were no differences in treatment: neither in first line therapy nor in the percentage of patients who received prostanoids at any time during follow up. The usage of prostanoids was very low in both groups. Two-thirds of the patients who died or underwent transplantation did so without taking prostanoids at any time. The 10-years survival analysis showed no significative difference between groups. Conclusions The prevalence of Eisenmenger syndrome is clearly lower in the pediatric population with CHD compared to the adult population. However, once Eisenmenger syndrome has developed, even though adults present greater hemodynamic severity, the clinical characteristics and the prognosis are similar in both groups. The usage of prostanoids is low in adulthood and in childhood, even in those with more severe forms of the disease. Funding Acknowledgement Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Ferrer, MSD, Janssen, GSK Table 1Figure 1

Short-term prognostic value of heart failure diagnosis in a contemporary cohort of patients with ACHD

Abstract Background Heart failure (HF) is one of the primary causes of premature death in patients with adult congenital heart disease (ACHD), yet population-specific data remains scarce. This study aims at assessing the short-term value of prognostic value of a heart failure diagnosis in patients with adult congenital heart disease, and its relation to ACHD classification systems such as the Bethesda disease complexity classification and the physiological severity classification. Methods This study included 3995 patients under active follow-up at our institution. We used a standardized definition of ACHD-HF. Predictors of the composite primary outcome: death, transplant or ventricular assist device (VAD) were identified using uni- and multivariable Cox proportional hazard models. Results Mean age was 35.7±13.3 years. According to the Bethesda disease complexity classification 33.5% of patients had simple defects, 55.6% moderate defects, and 10.9% severe defects. Based on the physiological severity classification, 18.0% of patients were in physiological stage A, 35.6% in physiological stage B, 42.2% in physiological stage C, and 4.2% in physiological stage D. The overall prevalence of ACHD-HF was 6.4%. During a median follow up of 1.8 (IQR 1.3–2.9) years, patients with ACHD-HF had a worse outcome with 27.3% reaching the composite primary endpoint of death, heart transplant or VAD implantation, compared to 1.4% of ACHD patients without HF. Event-free survival was 91.1%, 72.0% and 46.1% at 2, 4 and 6 years in patients with ACHD-HF, compared to 99.5%, 98.7% and 95.1% in ACHD patients without HF. In multivariable analysis the presence of heart failure (HR 4.6; 95% CI 2.9–7.2; p<0.001) and the physiological severity classification (HR 3.1; 95% CI 2.3–4.1; p<0.001) were independently associated with the composite primary outcome, whereas the Bethesda disease complexity classification was not (HR 0.9; 95% CI 0.7–1.3; p=0.701). Conclusion The risk of mortality, transplant and VAD is substantially increased in ACHD-HF patients. Our data provides insight into the short term prognostic value of a HF diagnosis in ACHD patients, helping physicians to gauge the prognosis in ACHD-HF and thereby guide management decisions. In addition to the physiological severity classification, the presence of HF proves to be a valuable prognostic marker in patients with ACHD. Funding Acknowledgement Type of funding sources: None. Kaplan–Meier analysesUni- and multivariable Cox regression

First-principles study of Ti-doped sapphire. II. Formation and reduction of complex defects

Eliminating the effect of residual infrared absorption in titanium sapphire remains a crucial task to fulfill, despite that this kind of laser crystal has been developed for decades. The ${\mathrm{Ti}}^{3+}\text{\ensuremath{-}}{\mathrm{Ti}}^{4+}$ (${\mathrm{Ti}}_{\mathrm{Al}}^{0}\text{\ensuremath{-}}{\mathrm{Ti}}_{\mathrm{Al}}^{1+}$) pair model is the most widely accepted explanation to this residual absorption, but theoretical analyses based on first-principles calculation have not yet depicted a clear picture for the variation of the ${\mathrm{Ti}}_{\mathrm{Al}}^{0}\text{\ensuremath{-}}{\mathrm{Ti}}_{\mathrm{Al}}^{1+}$ pair and a variety of other potentially important defects in titanium sapphire when fabricating conditions change. Here, we extend the work in [W. Jing, M. Liu, J. Wen, L. Ning, M. Yin, and C.-K. Duan, Phys. Rev. B 104, 165103 (2021)] about binding tendencies of ${\mathrm{Ti}}_{\mathrm{Al}}\text{\ensuremath{-}}{\mathrm{Ti}}_{\mathrm{Al}}$ pairs and optical transition properties to providing a comprehensive understanding of the formation and processing condition dependence of various potentially significant defects and complexes besides the (${\mathrm{Ti}}_{\mathrm{Al}}\text{\ensuremath{-}}{\mathrm{Ti}}_{\mathrm{Al}}{)}^{0,1+}$ pairs. Apart from the complexes composed of ${V}_{\mathrm{Al}}^{3\ensuremath{-}}$ and ${\mathrm{Ti}}_{\mathrm{Al}}^{0,1+}$ defects, two new significant negatively charged defects, ${({V}_{\mathrm{Al}}\text{\ensuremath{-}}{\mathrm{Al}}_{i}\text{\ensuremath{-}}{V}_{\mathrm{Al}})}^{3\ensuremath{-}}$ and ${({V}_{\mathrm{Al}}\text{\ensuremath{-}}{\mathrm{Ti}}_{i}\text{\ensuremath{-}}{V}_{\mathrm{Al}})}^{2\ensuremath{-}}$ are revealed. These two complexes are correspondingly an interstitial ${\mathrm{Al}}^{3+}$ and ${\mathrm{Ti}}^{4+}$ surrounded by two neighboring aluminium vacancies ${V}_{\mathrm{Al}}^{3\ensuremath{-}}$. We show that ${V}_{\mathrm{Al}}^{3\ensuremath{-}}$ plays the key role to stabilize ${\mathrm{Ti}}_{\mathrm{Al}}^{0}\text{\ensuremath{-}}{\mathrm{Ti}}_{\mathrm{Al}}^{1+}$ and form various stable complexes with ${\mathrm{Ti}}_{\mathrm{Al}}^{1+}$ and ${\mathrm{Ti}}_{\mathrm{Al}}^{0}\text{\ensuremath{-}}{\mathrm{Ti}}_{\mathrm{Al}}^{1+}$ in weak and moderate reductive atmospheres. Thus, besides annealing at strong reductive atmosphere at elevated temperatures, Al ion injection or annealing in Al vapor is a potential method to eliminate the harmful residual infrared absorption, which is pinpointed at the reduction of the concentration of ${V}_{\mathrm{Al}}^{3\ensuremath{-}}$ and its variant ${({V}_{\mathrm{Al}}\text{\ensuremath{-}}{\mathrm{Al}}_{i}\text{\ensuremath{-}}{V}_{\mathrm{Al}})}^{3\ensuremath{-}}$. While in extremely strong reductive atmosphere, isolated Ti substitution dominates over those complexes containing ${V}_{\mathrm{Al}}^{3\ensuremath{-}}$, but there still remains a tiny amount of ${\mathrm{Ti}}_{\mathrm{Al}}^{0}\text{\ensuremath{-}}{\mathrm{Ti}}_{\mathrm{Al}}^{1+}$ and ${\mathrm{Ti}}_{\mathrm{Al}}^{1+}$, which are charge compensators to balance the charge of trace amount ${\mathrm{Ti}}_{\mathrm{Al}}^{1\ensuremath{-}}$ further reduced from ${\mathrm{Ti}}_{\mathrm{Al}}^{0}$. And this effect can be further eliminated by lower temperature reductive-atmosphere annealing. In addition, we obtain a simple numerical expression to predict the achievable figure of merit when the concentration of ${\mathrm{Ti}}_{\mathrm{Al}}^{1+}$ is given. Formation energies for simple defects and binding energies for complexes obtained in this work may serve as the basis for simulations and design various quenching and annealing processes to further reduce harmful defect species in titanium sapphire.

Atrial septal defect in adulthood: a new paradigm for congenital heart disease

Atrial septal defects (ASDs) represent the most common congenital heart defect diagnosed in adulthood. Although considered a simple defect, challenges in optimal diagnostic and treatment options still exist due to great heterogeneity in terms of anatomy and time-related complications primarily arrhythmias, thromboembolism, right heart failure and, in a subset of patients, pulmonary arterial hypertension (PAH). Atrial septal defects call for tertiary expertise where all options may be considered, namely catheter vs. surgical closure, consideration of pre-closure ablation for patients with atrial tachycardia and suitability for closure or/and targeted therapy for patients with PAH. This review serves to update the clinician on the latest evidence, the nuances of optimal diagnostics, treatment options, and long-term follow-up care for patients with an ASD.

Design of tunable ring-shaped plasmonic photonic crystal filters infiltrated with optical fluids

Three different designs of plasmonic photonic crystal filters (two-channel, three-channel, and four-channel) are proposed and considered. The photonic crystal structures consist of standing rods made of Ag and GaAs, whereby introducing different simple or ring-shaped defects, two-, three-, or four-port filters are realized. Optical fluid is used instead of air as the background material, owing to its versatile benefits. By utilizing different combinations of optical fluids and plasmonic materials, multichannel filters are obtained which can function better by improving the structural parameters such as the rod’s radius. Considering the four-port filter, its applications as the power splitter are also investigated. For tuning the filter properties such as the resonance peak’s value and wavelength, impacts of Ag and GaAs rod radius on the transmission spectrum are examined. The following resonance peak’s value and FWHM are obtained for the proposed structures: two-channel filter (0.9, 4 nm), three-channel filter (0.8, 2 nm), four-channel filter (0.5, 10 nm). The proposed designed filters can be utilized in the photonic integrated circuits as well as the nanophotonics devices for medical and industrial applications.

The Diagnostic Yield of Fetal Echocardiography Indications in the Current Era

The aim of this study was to examine the diagnostic yield of current fetal echocardiography (FE) indications representing a recent era. FE reports of all pregnancies referred to two provincial FE programs from 2009 to 2018 were examined, identifying the indication for FE (14 categories), gestational age at referral, and whether there was no fetal heart disease (FHD), mild or possible FHD (e.g., simple ventricular septal defect, possible coarctation), or moderate or severe FHD. Over the study period, there were 19,310 unique FE referrals in Alberta (23.3±5.4weeks' gestation), including 1,907 (9.9%) with moderate or severe and 654 (3.4%) with mild or possible FHD. The most common referral indications included extracardiac pathology or markers (29.7%), maternal diabetes (18.3%), suspected FHD (17.7%), and family history of heart defects (17.7%). The highest yield for moderate or severe FHD was suspected FHD (41.1%; 95% CI, 39.4%-42.7%), followed by suspected or confirmed genetic disorder (15.4%; 95% CI, 12.6%-18.2%), twins or multiples (10.6%; 95% CI, 8.7%-12.5%), oligohydramnios (8.0%; 95% CI, 4.1%-11.9%), extracardiac pathology or markers (6.4%; 95% CI, 5.8%-7.1%), and heart not well seen (5.8%; 95% CI, 4.0%-7.6%). Lowest yields were observed for maternal diabetes (2.2%; 95% CI, 1.7%-2.7%) and family history of heart defects (1.7%; 95% CI, 1.3%-2.2%). Excluding suspected FHD, with two or more FE indications, all other indications demonstrated significant increases in yield of mild or possible (3.5% vs 1.9%, P<.001) and moderate or severe (7.2% vs 2.9%, P<.001) FHD. Suspected FHD provides the highest diagnostic yield of moderate or severe FHD. In contrast, maternal diabetes and family history of heart defects, among the most common referral indications, had diagnostic yields approaching general population risks. Even in the absence of suspected FHD, having two or more referral indications importantly increases the diagnostic yield of all other FE indications.

Long-term survival in patients with isolated pulmonary valve stenosis: a not so benign disease?

Background and objectivesDuring the last decades, the survival rates in patients with congenital heart disease have increased dramatically, particularly in patients with complex heart malformations. However, the survival in patients...

Modeling Disorder in Pyrochlores and Other Anion-Deficient Fluorite Structural Derivative Oxides.

Their very flexible chemistry gives oxide materials a richness in functionality and wide technological application. A specific group of oxides that have a structure related to fluorite but with less oxygen, termed anion-deficient fluorite structural derivatives and with pyrochlores being the most notable example, has been shown to exhibit a diversity of useful properties. For example, the possibility to undergo a transition from an ordered to disordered state allows these oxides to have high radiation tolerance. Atomistic-scale calculations in the form of molecular dynamics (MD) and density functional theory (DFT) have been extensively used to understand what drives this order/disorder transition. Here we give a brief overview of how atomistic-scale calculations are utilized in modeling disorder in pyrochlores and other anion-deficient fluorite structural derivatives. We discuss the modeling process from simple point defects to completely disordered structures, the dynamics during the disordering process, and the use of mathematical models to generate ordered solid-solution configurations. We also attempt to identify the challenges in modeling short range order and discuss future directions to more comprehensive models of the disordered structures.

Safety and feasibility of conduction system pacing in patients with congenital heart disease.

Conduction system pacing (CSP) has emerged as an ideal physiologic pacing strategy for patients with permanent pacing indications. We sought to evaluate the safety and feasibility of CSP in a consecutive series of unselected patients with congenital heart disease (CHD). Consecutive patients with CHD in which CSP was attempted were included. Safety and feasibility, implant tools and electrical parameters at implant and at follow-up were evaluated. A total of 20 patients were included (10 with a previous device). A total of 10 patients had complex forms of CHD, 9 moderate defects and 1 a simple defect. CSP was achieved in 75% of cases (10 His bundle pacing, 5 left bundle branch pacing) with left ventricular septal pacing in the remaining 5 patients. Procedure times and fluoroscopy times were prolongued (126 ± 82 min and 27 ± 30 min, respectively). Ventricular lead implant times widely varied ranging from 4 to 115 min, (mean 31 ± 28 min) and the use of multiple delivery sheaths was frequent (50%). The QRS width was reduced from 145 ± 36 ms at baseline to 116 ± 18 ms with CSP. Implant electrical parameters included: CSP pacing threshold 0.95 ± 0.65 V; R wave amplitude 9.2 ± 8.8 mV and pacing impedance 632 ± 183 Ohms, and remained stable at a median follow-up of 478 days (interquartile range: 225-567). Systemic ventricle systolic function and NYHA class (1.50 ± 0.51 vs. 1.10 ± 0.31; p = .008) significantly improved at follow-up. Lead revision was required in one patient at Day 4. Permanent CSP is safe and feasible in patients with CHD although implant technique is complex.

Optimizing Care for Adults with Congenital Heart Disease: Results of a Conjoint Analysis Based on a Nationwide Sample of Patients Included in the German National Register.

(1) Background: Congenital heart disease (CHD) requires lifelong specialized care. Failure to follow up and gaps in care are common in this group and lead to increased morbidity/mortality. We evaluated patients’ perceived needs and expectations regarding specialized care using state-of-the-art statistical and market research techniques based on a nationwide sample of CHD patients. (2) Methods: A random sample of adults with CHD registered in the German National Register for Congenital Heart Defects were invited to answer an adaptive online questionnaire based on the conjoint analysis (CA) technique. CA determines the relative importance of various aspects of health care provision and allows individuals to trade between characteristics, thus recognizing limited resources. (3) Results: 637 patients participated (mean age 33.8 ± 12.6 years; 55.6% female; disease complexity: simple defect 12.6%, moderate complexity 40.3%, complex CHD 40.2%) in the analysis. Patients assigned the highest relative importance to aspects of patient–physician communication, physician qualifications, waiting time, medical care, and medical equipment. Comfort-related aspects such as driving time or hotel aspects of care received much lower scores. We identified four well-defined clusters of patients with differing expectation patterns: (i) time sensitive patients; (ii) excellence seeking patients; (iii) continuity seekers, and (iv) support seeking patients. (4) Conclusions: Adult CHD patients rank effective patient–physician interaction and communication as the most important factors. As we identified significant heterogeneity between CHD patients, centers should cater for individual preferences and integrate individual needs into treatment plans to prevent failure to follow up and ensure patient compliance.

Is N-terminal pro-brain type natriuretic peptide a useful marker in newborns with heart defects?

Heart diseases are currently a significant cause of morbidity and mortality in newborns. The existing diagnostic methods are often not sufficient or, in many cases, cannot be used. Great advances have been achieved in medical knowledge concerning biomarkers for the diagnosis of circulatory system disorders in adult patients. Among these biomarkers, N-terminal pro-brain type natriuretic peptide (NT-proBNP) plays a main role. However, in the existing literature, there is not enough data concerning the physiological features of this biomarker in newborns and its potential use in neonatal cardiac diagnostics. To evaluate the diagnostic usefulness of NT-proBNP measurements in correlation with other markers of circulatory failure and myocardial damage in newborns with heart defects. This study involved 126 newborns. Patients were divided into 2 main groups: group I included infants with congenital heart defects (CHD) and group II (control) included healthy neonates. Newborns with CHD were further divided into 2 subgroups: group Ia with simple shunts and group Ib with combined heart defects. Patients in group I were further divided according to the hemodynamic significance of CHD. The NT-proBNP level was evaluated using the CARDIAC proBNP immunologic test (Cobas h232; Roche Diagnostics, Basel, Switzerland). The NT-proBNP concentrations were significantly higher in newborns with CHD compared to healthy ones. Newborns with combined heart defects had higher levels of NT-proBNP than newborns with simple shunts. The NT-proBNP concentrations in newborns with CHD correlated with echocardiographic parameters of hemodynamic significance and with left ventricular ejection fraction (LVEF). Additionally, NT-proBNP correlated with clinical symptoms of heart failure (HF; Ross classification, Reithmann's score). Statistically significant differences in NT-proBNP level between newborns with heart defects and healthy controls were shown. In newborns with heart diseases, significant correlations were found between NT-proBNP level and the type of heart defect (simple shunt or combined defects), the hemodynamic significance of the defect, LVEF, and the clinical intensity of HF.

Ultra-compact terahertz all-optical logic comparator on GaAs photonic crystal platform

Photonic crystals are suitable structures for designing various types of optical logic circuits. In this paper, an all-optical comparator is designed and simulated using two-dimensional photonic crystals. A combination of linear and point defects has been used in the proposed structure. The small number of point defects and the use of simple linear defects make this comparator simple design. One of the important features of this comparator is that it uses two outputs to compare the input bits. A small structure is used for the proposed optical comparator. Also, this structure has a delay time of 0.07 ps, which is due to the very small size of the structure and the use of a small number of defects. The simulation results show that the bit rate for the proposed comparator is 3.33 Tb/s. Therefore, this structure can be suitable for use in high-speed logic circuits.

Key considerations in the approach to congenital heart disease in dogs and cats.

Congenital heart disease is an important subset of all cardiovascular disease in dogs and cats that is present at birth and most often detected in young animals but can be diagnosed in adulthood. The range of abnormalities that can occur during development of the heart is vast incorporating simple and complex defects, varying degrees of severity and clinical presentations that include heart failure and cyanosis. While some defects do not result in morbidity in an individual animal, others cause severe clinical signs and death at a young age. Advances in imaging and expanding treatment options offer increasingly more possibilities in the diagnosis and management of congenital heart disease which is the focus of this review. The objective is to provide a broad overview of current practice and highlight key aspects to guide practitioners in their approach to congenital heart disease diagnosis and knowledge of available treatment options.

Promoting the Methane Oxidation on Pd/CeO2 Catalyst by Increasing the Surface Oxygen Mobility via Defect Engineering

AbstractMethane is a useful chemical resource, but removing it, a powerful greenhouse gas, is important to prevent global warming. In this study, the methane oxidation activity of conventional Pd/CeO2 catalyst was improved by enhancing the oxygen mobility of ceria surface via the simple defect engineering. Raman spectroscopy demonstrates that the defect concentration of ceria surface is reduced after high temperature treatments. Cryogenic hydrogen‐temperature‐programmed‐reduction curves indicate that the surface oxygen of ceria in Pd/CeO2 catalysts with the reduced defect concentration became mobile, resulting in the facile reduction at the lower temperature. X‐ray diffraction, X‐ray photoelectron and X‐ray adsorption spectroscopies show that the improvement in the surface oxygen mobility does not originate from the change in PdOx particle size nor its oxidation state. As a result, the temperature of 50 % conversion of methane shifted by 25 °C to the lower temperature on Pd/CeO2 catalyst with the reduced defect concentration. This work highlights that the catalytic activity can be enhanced by promoting the active participation of the surface oxygen of support.

Rational Passivation of Sulfur Vacancy Defects in Two-Dimensional Transition Metal Dichalcogenides.

Structural defects vary the optoelectronic properties of monolayer transition metal dichalcogenides, leading to concerted efforts to control defect type and density via materials growth or postgrowth passivation. Here, we explore a simple chemical treatment that allows on–off switching of low-lying, defect-localized exciton states, leading to tunable emission properties. Using steady-state and ultrafast optical spectroscopy, supported by ab initio calculations, we show that passivation of sulfur vacancy defects, which act as exciton traps in monolayer MoS2 and WS2, allows for controllable and improved mobilities and an increase in photoluminescence up to 275-fold, more than twice the value achieved by other chemical treatments. Our findings suggest a route for simple and rational defect engineering strategies for tunable and switchable electronic and excitonic properties through passivation.

Properties of irradiated sodium borosilicate glasses from experiment and atomistic simulations

AbstractWith a combination of atomistic modeling and experimental techniques, we have investigated the structural and elastic parameters of sodium borosilicate glasses, including irradiation‐induced changes. Both approaches show that the Young's modulus depends linearly on the density of material. The simulated glass density and boron speciation match also the estimates by independent, elemental glass composition‐based models, indicating that atomistic simulations could be used in validation of theoretical models and experimental results. This allows us to formulate Young's modulus—density relationships for investigated borosilicate glasses and test the existing empirical model for description of Vickers hardness of these materials. The simulation of irradiation reveals a change of B[4] content under irradiation. By applying a simple defects accumulation procedure, we are able to correctly reproduce the measured critical irradiation dose of ~0.1 dpa and provide reasonable information on density change and stored internal energy. With the obtained agreements between the experimental and simulation results, we obtained superior insights into the atomic‐scale structural evolution of irradiated borosilicate glasses.

Bicuspid Aortic Valve in Infants, Children, and Adolescents: A Review for Primary Care Providers.

1. Talha Niaz, MBBS* 2. Jonathan N. Johnson, MD*,† 3. Frank Cetta, MD*,† 4. Timothy M. Olson, MD*,† 5. Donald J. Hagler, MD*,† 1. *Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, and 2. †Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN * Abbreviations: AHA : : American Heart Association BAV : : bicuspid aortic valve TTE : : transthoracic echocardiography Bicuspid aortic valve is the most common congenital heart defect in children, adolescents, and adults. Primary care providers play an important role in screening, referral, and follow-up of these patients and should be aware of the family screening guidelines, sports participation recommendations, and periodic follow-up requirements for adequate surveillance of the complications that arise from bicuspid aortic valve. After reading this article, readers should be able to: 1. Describe the epidemiology and anatomy of bicuspid aortic valve (BAV). 2. Understand the clinical presentation and diagnosis of BAV in infants, children, and adolescents. 3. Identify the various complications of BAV disease. 4. Discuss the management and follow-up requirements for BAV. 5. Analyze the family screening and sports participation guidelines for patients with BAV. Bicuspid aortic valve (BAV) is the most common congenital heart defect in children, adolescents, and adults. (1) It is a heterogeneous disease that affects both the aortic valve and the aorta. It can lead to many complications, including aortic valve stenosis, regurgitation, or endocarditis. (2)(3) It also can lead to dilation of the aorta, predisposing individuals to a significantly higher risk of aortic aneurysm and dissection. (4) Although most individuals with BAV present with these long-term complications during adulthood, a considerable number of patients may also present during childhood and adolescence with early-onset disease; that may require interventions in up to 12% to 15% of the patients. (5)(6) Therefore, patients with BAV require lifelong follow-up and surveillance. BAV has multiple implications in terms of sports participation and family screening, making it an important subject for primary care providers. This article reviews the anatomy, genetics, presentation, diagnosis, …

Defect engineering-induced porosity in graphene quantum dots embedded metal-organic frameworks for enhanced benzene and toluene adsorption

The emerging environmental issues necessitate the engineering of novel and well-designed nanoadsorbents for advanced separation and purification applications. Despite recent advances, the facile synthesis of hierarchical micro-mesoporous metal-organic frameworks (MOFs) with tuned structures has remained a challenge. Herein, we report a simple defect engineering approach to manipulate the framework, induce mesoporosity, and crease large pore volumes in MIL-101(Cr) by embedding graphene quantum dots (GQDs) during its self-assembly process. For instance, MIL-101@GQD-3 (Vmeso: 0.68 and Vtot: 1.87 cm3/g) exhibited 300.0% and 53.3% more meso and total pore volume compared to those of the conventional MIL-101 (Vmeso: 0.17 and Vtot: 1.22 cm3/g), respectively, resulting in 1.7 and 2.8 times greater benzene and toluene loading at 1 bar and 25 °C. In addition, we found that MIL-101@GQD-3 retained its superiority over a wide range of VOC concentrations and operating temperature (25–55 °C) with great cyclic capacity and energy-efficient regeneration. Considering the simplicity of the adopted technique to induce mesoporosity and tune the nanoporous structure of MOFs, the presented GQD incorporation technique is expected to provide a new pathway for the facile synthesis of advanced materials for environmental applications.

Selexipag for pulmonary arterial hypertension in a wide range of adult congenital heart disease

BackgroundSelexipag has been recognised as effective treatment for pulmonary arterial hypertension (PAH). However, evidence for its use in PAH associated with congenital heart disease (CHD) is limited to those with PAH after simple defect correction. We evaluated the response to selexipag in a wider range of PAH-CHD patients. MethodsProspective observational cohort study recruiting adults with PAH-CHD who were initiated on selexipag treatment between 2017 and 2019 at five expert centres. ResultsOf 34 patients (age 46 ± 14.8 years, 67.6% female, 61.8% dual therapy, 32.4% complex shunt), 21 had Eisenmenger syndrome, 2 systemic-to-pulmonary shunt, and 11 PAH after defect correction. Majority of patients tolerated only low doses, with a median maintenance dose of 400 (IQR 200–800) μg twice daily. Ten (29.4%) patients, primarily with Eisenmenger syndrome, discontinued treatment due to unmanageable side effects. Median exposure to selexipag was 16.1 (IQR 6.0–25.8) months. Morbidity/mortality was high for patients with Eisenmenger syndrome, whereas patients with PAH after defect correction had an excellent event-free survival (Log-rank p = 0.04). Following current European guidelines, after 12 months of treatment, one patient with Eisenmenger syndrome and five patients with PAH after defect correction improved from ‘Intermediate’ to ‘Low’ risk, whereas two patients with Eisenmenger syndrome worsened in risk status (p = 0.028). Six-minute walk distance and N-terminal pro-brain natriuretic peptide levels remained stable, whereas improvement in World Health Organization functional class was observed in nine patients. ConclusionThese findings suggest that patients with PAH after defect correction may have better tolerability and more clinical benefit from selexipag than patients with Eisenmenger syndrome.