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We report a new synthesis method for multiple-walled nested thin-film nanostructures by combining hydrothermal growth methods with atomic layer deposition (ALD) thin-film technology and sacrificial films, thereby increasing the surface-to-volume ratio to improve the sensing performance of novel ZnO gas sensors. Single-crystal ZnO nanorods serve as the core of the nanostructure assembly and were synthesized hydrothermally on fine-grained ALD ZnO seed films. Subsequently, the ZnO core nanotubes were coated with alternating sacrificial coaxial 3D wrap-around ALD Al2O3 films and ALD ZnO films. Basically, the center nanorod was coated with an ALD 3D wrap-around Al2O3 sacrificial layer to realize a nested coaxial ZnO thin-film nanotube. To increase the surface-to-volume ratio of the nested multiple-film nanostructure, both the front and backside of the nested coaxial ZnO films must be exposed by selectively removing the intermittent Al2O3 sacrificial films. The selective removal of the sacrificial films exposes the front and backside of the free-standing ZnO films for interaction with target gases during sensing operation while steadily increasing the surface-to-volume ratio. The sensing response of the novel ZnO gas sensor architecture with nested nanotubes achieved a maximum 150% enhancement at low temperature compared to a conventional ZnO nanorod sensor.

Metal-organic frameworks are attractive adsorbents for gas storage and separations, but appropriate heat dissipation is important for practical application. Here the authors use experiment and theory to show the impact of liquid adsorbates on thermal transport in metal-organic frameworks.

We leveraged chemical-induced changes to microwave signal propagation characteristics (i.e., S-parameters) to characterize the detection of aliphatic alcohol (methanol, ethanol, and 2-propanol) vapors using TCNQ-doped HKUST-1 metal-organic-framework films as the sensing material, at temperatures under 100 °C. We show that the sensitivity of aliphatic alcohol detection depends on the oxidation potential of the analyte, and the impedance of the detection setup depends on the analyte-loading of the sensing medium. The microwaves-based detection technique can also afford new mechanistic insights into VOC detection, with surface-anchored metal-organic frameworks (SURMOFs), which is inaccessible with the traditional coulometric (i.e., resistance-based) measurements.

The most common gas sensors are based on chemically induced changes in electrical resistivity and necessarily involve making imperfect electrical contacts to the sensing materials, which introduce errors into the measurements. We leverage thermal- and chemical-induced changes in microwave propagation characteristics (i.e., S-parameters) to compare ZnO and surface-anchored metal–organic-framework (HKUST-1 MOF) thin films as sensing materials for detecting ethanol vapor, a typical volatile organic compound (VOC), at low temperatures. We show that the microwave propagation technique can detect ethanol at relatively low temperatures (

Porous hybrid materials and MOF (Metal–Organic-Framework) films represent modern designer materials that exhibit many requirements of a near ideal and tunable future thermoelectric (TE) material. In contrast to traditional semiconducting bulk TE materials, porous hybrid MOF templates can be used to overcome some of the constraints of physics in bulk TE materials. These porous hybrid systems are amenable for simulation and modeling to design novel optimized electron-crystal phonon-glass materials with potentially very high ZT (figure of merit) numbers. Porous MOF and hybrid materials possess an ultra-low thermal conductivity, which can be further modulated by phonon engineering within their complex porous and hierarchical architecture to advance the TE figure of merit (ZT). This Perspective review discusses recent results of MOF TE materials and provides a future outlook and the vision to the search for the next generation TE porous hybrid and MOF materials, which could be part of the green renewable energy revolution with novel materials of sustainably high ZT values.

Background: In patients with low-gradient (LG) aortic stenosis (AS), confirming disease severity and indication of intervention often requires dobutamine stress echocardiography (DSE) or aortic valve calcium scoring by computed tomography. We hypothesized that the mean transvalvular pressure gradient to effective orifice area ratio (MG/EOA, in mm Hg/cm2) measured during rest echocardiography identifies true-severe AS (TSAS) and is associated with clinical outcomes in patients with low-flow, LG-AS. Objectives: The purpose of this study was to evaluate the diagnostic and prognostic value of MG/EOA ratio. Methods: The diagnostic accuracy of MG/EOA ratio to identify TSAS was retrospectively assessed in: 1) an in vitro data set obtained in a circulatory model including 93 experimental conditions; and 2) an in vivo data set of 188 patients from the TOPAS (True or Pseudo-Severe Aortic Stenosis) study (NCT01835028). Receiver operating characteristic curves were used to assess the diagnostic accuracy of MG/EOA ratio for identifying TSAS, and Cox proportional hazards regression analyses were performed to assess its association with clinical outcomes. Results: The optimal cutoff of MG/EOA ratio to identify TSAS in patients with low-flow, LG-AS was ≥25 mm Hg/cm2 (correct classification 85%), as well as in vitro (100%). During a median follow-up of 1.41 ± 0.75 years, 146 (78%) patients met the composite endpoint of aortic valve replacement or all-cause mortality. A MG/EOA ratio ≥25 mm Hg/cm2 was independently associated with an increased risk of the composite endpoint (adjusted HR: 2.36 [95% CI: 1.63-3.42], P

Abstract Guidelines recommend transesophageal echocardiography (TEE) before cardioversion in thrombogenic arrhythmias when the requirement of ≥ 3 weeks of anticoagulation is not met. Current data to support this approach, especially with direct oral anticoagulants (DOAC), are scarce. We analyzed consecutive elective pre-cardioversion TEE in a high-volume electrophysiology center for the occurrence of left atrial appendage (LAA) thrombi or reduced LAA flow velocity. Possible predictors were recorded and compared in a multivariate logistic regression analysis. Consecutive pre-cardioversion TEE in 512 patients (148 female, median age 69 years) were included. In all patients, indication for TEE was either intake of anticoagulation

Background: At the beginning of the COVID-19 pandemic, professionals in charge of particularly vulnerable populations, such as adult congenital heart disease (ACHD) patients, were confronted with difficult decision-making. We aimed to assess changes in risk stratification and outcomes of ACHD patients suffering from COVID-19 between March 2020 and April 2021. Methods and results: Risk stratification among ACHD experts (before and after the first outcome data were available) was assessed by means of questionnaires. In addition, COVID-19 cases and the corresponding patient characteristics were recorded among participating centres. Predictors for the outcome of interest (complicated disease course) were assessed by means of multivariable logistic regression models calculated with cluster-robust standard errors. When assessing the importance of general and ACHD specific risk factors for a complicated disease course, their overall importance and the corresponding risk perception among ACHD experts decreased over time. Overall, 638 patients (n = 168 during the first wave and n = 470 during the subsequent waves) were included (median age 34 years, 52% women). Main independent predictors for a complicated disease course were male sex, increasing age, a BMI >25 kg/m2, having ≥2 comorbidities, suffering from a cyanotic heart disease or having suffered COVID-19 in the first wave vs. subsequent waves. Conclusions: Apart from cyanotic heart disease, general risk factors for poor outcome in case of COVID-19 reported in the general population are equally important among ACHD patients. Risk perception among ACHD experts decreased during the course of the pandemic.

Abstract Aim Due to improved therapy in childhood, many patients with congenital heart disease reach adulthood and are termed adults with congenital heart disease (ACHD). ACHD often develop heart failure (HF) as a consequence of initial palliative surgery or complex anatomy and subsequently require advanced HF therapy. ACHD are usually excluded from trials evaluating heart failure therapies, and in this context, more data about heart failure trajectories in ACHD are needed to guide the management of ACHD suffering from HF. Methods and results The pAtients pResenTing with cOngenital heaRt dIseAse Register (ARTORIA‐R) will collect data from ACHD evaluated or listed for heart or heart‐combined organ transplantation from 16 countries in Europe and the Asia/Pacific region. We plan retrospective collection of data from 1989–2020 and will include patients prospectively. Additional organizations and hospitals in charge of transplantation of ACHD will be asked in the future to contribute data to the register. The primary outcome is the combined endpoint of delisting due to clinical worsening or death on the waiting list. The secondary outcome is delisting due to clinical improvement while on the waiting list. All‐cause mortality following transplantation will also be assessed. The data will be entered into an electronic database with access to the investigators participating in the register. All variables of the register reflect key components important for listing of the patients or assessing current HF treatment. Conclusion The ARTORIA‐R will provide robust information on current management and outcomes of adults with congenital heart disease suffering from advanced heart failure.

Abstract Aims The Fontan operation has resulted in improved survival in patients with single‐ventricle congenital heart disease. As a result, there is a growing population of teenagers and adults with a Fontan circulation. Many co‐morbidities have been increasingly recognized in this population due to the unique features of the Fontan circulation. Standardization of how Fontan co‐morbid conditions are defined will help facilitate understanding, consistency and interpretability of research and clinical experience. Unifying common language usage in Fontan is a critical precursor step for data comparison of research findings and clinical outcomes and ultimately accelerating improvements in management for this growing group of patients. This manuscript aimed to create unified definitions for morbidities seen after the Fontan palliation. Methods In association of many congenital heart disease organizations, this work used Delphi methodology to reach a broad consensus among recognized experts regarding commonly used terms in Fontan care and research. Each definition underwent at least three rounds of revisions to reach a final definition through surveys sent to experts in the field of single‐ventricle care. Results The process of reaching a consensus on multiple morbidities associated with the Fontan procedure is summarized in this manuscript. The different versions that preceded reaching the consensus are also presented in the Supporting Information. Table 1 represents the final definitions according to the consensus. Conclusions We propose the use of these definitions for clinical care, future research studies, registry development and clinical trials.

Sudden cardiac death (SCD) is one of the most frequent causes of death in adult patients with congenital heart disease (ACHD). Despite the rare frequency of its occurrence, the incident appears often when unexpected, and many affected patients had not been identified priorly. Data on predictors for SCD are limited since the total number of ACHD is low. As the cohort is heterogeneous, it is difficult to define uniform risk factors that apply to all ACHD. Complexity of the congenital heart disease appears to play a role, but other factors may also be relevant and have not been sufficiently identified yet. In current guidelines, recommendations are primarily based on data of patients without congenital heart disease.With the ATROPOS registry, we are aiming to identify reliable risk factors for SCD. The registry enables physicians globally to include patients with congenital heart disease who died of or survived SCD. After acquisition, the data will be compared to an age and complexity of disease matched cohort to perform a case-control analysis. Subsequently, a further analysis will be performed using deep learning algorithms with artificial intelligence to amplify the gathered information and find reliable risk factors.

Abstract Background Deep learning algorithms are increasingly used for automatic medical imaging analysis and cardiac chamber segmentation. Especially in congenital heart disease, obtaining a sufficient number of training images and data anonymity issues remain of concern. Methods Progressive generative adversarial networks (PG-GAN) were trained on cardiac magnetic resonance imaging (MRI) frames from a nationwide prospective study to generate synthetic MRI frames. These synthetic frames were subsequently used to train segmentation networks (U-Net) and the quality of the synthetic training images, as well as the performance of the segmentation network was compared to U-Net-based solutions trained entirely on patient data. Results Cardiac MRI data from 303 patients with Tetralogy of Fallot were used for PG-GAN training. Using this model, we generated 100,000 synthetic images with a resolution of 256 × 256 pixels in 4-chamber and 2-chamber views. All synthetic samples were classified as anatomically plausible by human observers. The segmentation performance of the U-Net trained on data from 42 separate patients was statistically significantly better compared to the PG-GAN based training in an external dataset of 50 patients, however, the actual difference in segmentation quality was negligible (

ObjectivesWristband activity trackers (accelerometers) could serve as a convenient monitoring tool to continuously quantify physical activity throughout the day. We aim to provide reference values for the use of these devices in healthy children.MethodsChildren were recruited at a local school and provided with activity trackers (Fitbit Charge 2). Pupils were instructed to wear devices during all normal daytime activities over a period of 11–15 days. Demographic data, total number of daily steps and heart rate were recorded. In addition, all children/parents were asked to complete a questionnaire providing information about daily physical routine (mode of transport to school, sporting activities as well as sport club memberships).ResultsThree hundred two children (54.6% boys; median age 8.7 years) participated in this prospective study. Median wearing time of the device was 12.1 h/day. Overall, the median daily total step count was 12,095. Median step counts/day were significantly higher in boys compared to girls (13,015 vs. 11,305 steps/day; p < 0.0001). In addition, step counts were significantly higher during the week, compared to weekend days. The effect of age on daily step count was found to be non-linear: the total daily step count increased from 6 to 8.5 years of age, while older children (aged >8.5 years) had lower step counts compared to the younger children. Significant predictors of the daily step count were male gender (+1,324.9 steps, p = 0.0008), mode of transportation to school (walking, bicycle, scooter: +865.5 steps p = 0.049), active membership in a sports club (+1,324.9 steps/day, p = 0.0008), and number of structured units of physical exercise performed (+336.5/per 45 min, p < 0.0001). Severe obesity was associated with a significant reduction in total daily step count (−3037.7 steps/day, p = 0.015).ConclusionOur prospective cohort study of healthy school children provides reference values for wristband accelerometers in normal individuals. In addition, it clarifies the effect of age, body weight and lifestyle on normal daily step counts in school children. This data should be helpful to judge the degree of physical limitation of patients compared to healthy peers.

Background No randomized comparison of early (ie, ≤3 months) aortic valve replacement (AVR) versus conservative management or of transcatheter AVR (TAVR) versus surgical AVR has been conducted in patients with low‐flow, low‐gradient (LFLG) aortic stenosis (AS). Methods and Results A total of 481 consecutive patients (75±10 years; 71% men) with LFLG AS (aortic valve area ≤0.6 cm2/m2 and mean gradient

Background Women are underrepresented in leading medical positions and academia. The gender-gap in authorship of congenital heart disease (CHD) publications remains unknown. As determinants of gender equity in this field are poorly characterised, we aimed to quantify and characterise publications in CHD and to assess factors associated with female representation in research.Methods and results We identified 35 118 CHD publications between 2006 and 2015 for which author gender could be ascertained. Overall, 25.0% of all authors were female. Women accounted for 30.2% and 20.8% of all first and senior authorship positions with great geographic heterogeneity. While globally female first and senior authorship increased by 0.8% and 0.6%/year, some geographic regions showed no improvement in gender representation. Significant predictors of female first authorship on logistic regression analysis were country gross domestic product, human development index, gender inequality index and a female senior author (p

BACKGROUND:Transcatheter aortic valve implantation (TAVI) has become the treatment of choice in patients with severe aortic valve stenosis who are not eligible for operative replacement and an alternative for those with high surgical risk. Due to high age and smoking history in a high proportion of TAVI patients, suspicious findings are frequently observed in pre-procedural chest computer tomography (CCT). METHODS:CCT scans of 484 consecutive patients undergoing TAVI were evaluated for incidentally discovered solitary pulmonary nodules (SPN). RESULTS:In the entire study population, SPN ≥ 5 mm were found in 87 patients (18%). These patients were compared to 150 patients who were incidentally collected from the 397 patients without SPN or with SPN < 5 mm (control group). After a median follow-up of 455 days, lung cancer was diagnosed in only two patients. Neither SPN ≥ 5 mm (p = 0.579) nor SPN > 8 mm (p = 0.328) were significant predictors of overall survival. CONCLUSIONS:Despite the high prevalence of SPNs in this single center TAVI cohort lung cancer incidence at midterm follow-up seems to be low. Thus, aggressive diagnostic approaches for incidentally discovered SPN during TAVI evaluation should not delay the treatment of aortic stenosis. Unless advanced thoracic malignancy is obvious, the well documented reduction of morbidity and mortality by TAVI outweighs potentially harmful delays regarding further diagnostics. Standard guideline-approved procedure for SPN can be safely performed after TAVI.

Background. Transcatheter aortic valve implantation (TAVI) is widely used in high risk patients (pts) with aortic stenosis. Underlying chronic kidney disease implicates a high risk of postprocedural acute kidney injury (AKI). We analyzed its occurrence, impact on hospital stay, and mortality. Methods. 150 consecutive pts underwent TAVI in our institution (mean age 81 ± 7 years; logistic EuroSCORE 24 ± 15%). AKI definition was a creatinine rise of 26.5 μmol/L or more within 48 hours postprocedural. Ten patients on chronic hemodialysis were excluded. Results. AKI occurred in 28 pts (20%). Baseline creatinine was higher in AKI pts (126.4 ± 59.2 μmol/L versus 108.7 ± 45.1 μmol/L, P=0.09). Contrast media use was distributed evenly. Both, 30-day mortality (29% versus 7%, P

We report the fabrication, characterization and simulation of Si nanowire SONOS-like non-volatile memory with HfO2 charge trapping layers of varying thicknesses. The memory cells, which are fabricated by self-aligning in situ grown Si nanowires, exhibit high performance, i.e. fast program/erase operations, long retention time and good endurance. The effect of the trapping layer thickness of the nanowire memory cells has been experimentally measured and studied by simulation. As the thickness of HfO2 increases from 5 to 30 nm, the charge trap density increases as expected, while the program/erase speed and retention remain the same. These data indicate that the electric field across the tunneling oxide is not affected by HfO2 thickness, which is in good agreement with simulation results. Our work also shows that the Omega gate structure improves the program speed and retention time for memory applications. [ABSTRACT FROM AUTHOR]