Mechanical Compatibility between Mg3(Sb,Bi)2 and MgAgSb in Thermoelectric Modules.

Thermoelectric (TE) modules are exposed to temperature gradients and repeated thermal cycles during their operation; therefore, mechanically robust n- and p-type legs are required to ensure their structural integrity. The difference in the coefficients of thermal expansion (CTEs) of the two legs of a TE module can cause stress buildup and the deterioration of performance with frequent thermal cycles. Recently, n-type Mg3Sb2 and p-type MgAgSb have become two promising components of low-temperature TE modules because of to their high TE performance, nontoxicity, and abundance. However, the CTEs of n-Mg3Sb2 and p-MgAgSb differ by approximately 10%. Furthermore, the oxidation resistances of these materials at increased temperatures are unclear. This work manipulates the thermal expansion of Mg3Sb2 by alloying it with Mg3Bi2. The addition of Bi to Mg3Sb2 reduces the coefficient of linear thermal expansion from 22.6 × 10-6 to 21.2 × 10-6 K-1 for Mg3Sb1.5Bi0.5, which is in excellent agreement with that of MgAgSb (21 × 10-6 K-1). Furthermore, thermogravimetric data indicate that both Mg3Sb1.5Bi0.5 and MgAgSb are stable in air and Ar at temperatures below ∼570 K. The results suggest the compatibility and robustness of Mg3Sb1.5Bi0.5 and MgAgSb as a pair of thermoelectric legs for low-temperature TE modules.

Utility of perinatal natriuretic peptide for predicting neonatal heart failure.

BACKGROUND: We evaluated the significance of perinatal plasma natriuretic peptide (NP) levels in neonates with congenital heart defects (CHDs) or arrhythmias and determined whether measurement of perinatal plasma NP levels and echocardiographic assessment in utero could predict heart failure after birth. METHODS: The study was conducted between 2012 and 2016 to evaluate the correlation of perinatal atrial NP (ANP) and brain NP (BNP) levels at birth with the modified Ross score after birth and the cardiovascular profile (CVP) score before birth. RESULTS: A total of 122 singletons with CHDs or arrhythmias and 27 controls were analyzed. Neonatal blood sampling was performed at a median of 0.7 h (range, 0.1-1.5) after birth. The neonatal plasma ANP and BNP levels shortly after birth were significantly higher than those in the umbilical artery (UA) plasma. The ANP and BNP levels in UA and neonatal blood were correlated with the modified Ross score. The neonatal plasma ANP and BNP levels and the modified Ross scores were inversely correlated with the CVP score in neonates with CHDs or arrhythmias. The area under the receiver operating characteristic curve of UA ANP levels for predicting neonatal heart failure was highest among those for the CVP score, perinatal plasma ANP and BNP levels, and their combinations. CONCLUSIONS: The plasma ANP and BNP levels increased markedly shortly after birth. Assessment of the UA plasma ANP level at birth and the CVP score in utero may be utilized to predict neonatal heart failure.

Plasma natriuretic peptide levels reflect the status of the heart failure in fetuses with arrhythmia.

OBJECTIVES: To evaluate the significance of natriuretic peptide (NP) levels in fetal arrhythmia. STUDY DESIGN: Cardiovascular profile (CVP) scores and umbilical vein (UV) NP levels at birth were compared by different fetal arrhythmia statuses. RESULTS: Fetal tachyarrhythmia (n = 22), bradyarrhythmia (n = 12), extrasystole (n = 12) and controls (n = 127) were enrolled in this study. Fetal antiarrhythmic therapy was performed in fetuses with tachyarrhythmia (n = 18) and bradyarrhythmia (n = 5). Fetal arrhythmias were divided into three groups: group A (arrhythmia controlled at birth, n = 17), Group B (arrhythmia uncontrolled at birth, n = 9) and Group C (fetal therapy not indicated, n = 20). Group B had significantly lower CVP scores and higher NP levels than the other two groups and controls (p < .01). Groups A and C had significantly lower CVP scores than controls, but NP levels in Groups A and C showed no differences compared with controls. CONCLUSIONS: UV NP concentrations reflect the severity of fetal arrhythmia and responses to fetal therapy.

Synthesis, microstructure, multifunctional properties of mayenite Ca12Al14O33 (C12A7) cement and graphene oxide (GO) composites.

The Pristine Mayenite Ca12Al14O33 (C12A7) Cement was simply synthesized by using solid-state reaction. The C12A7 and Graphene Oxide (GO) composites (C12A7_GO-x) with various contents of the GO suspension loading (x = 0 wt%, 1 wt%, 2 wt%, 3 wt%, and 4 wt%) were directly prepared by mixing the C12A7 and GO. X-ray diffraction results of pristine C12A7 and all C12A7_GO composites indicated a pure phase corresponding to the standard of C12A7 cement. Raman spectroscopy confirmed the existence of GO in all C12A7_GO samples. Scanning Electron Microscopy (SEM) showed the micrometer grain sizes and the occurrence of grain boundary interfaces for GO incorporation in all C12A7_GO samples. UV-Vis spectroscopy revealed the absorption value of all C12A7_GO samples and red shift near longer wavelengths when increasing the GO concentrations. The dielectric constant of C12A7_GO composites can be explained by the high density of free electron charges for the interfacial polarization on the GO surface. The maximum specific capacitance of C12A7_GO-4 electrode of 21.514 at a current density of 0.2 A g-1 can be attributed to the increase in the electrochemically active surface area for the formation of the electrical double layer capacitors behavior and the effects of high surface area GO connections. Also, the mechanical properties exhibited an increase in Vickers indenter hardness (HV) values with increasing GO contents. The highest HV value was 117.8 HV/2 kg at the C12A7_GO-4 sample. These results showed that the composite materials of the pristine C12A7 cement with GO were highly efficient. All in all, the GO material contained a high potential for enhancing low-cost cement materials in multifunctional properties such as optical, dielectric, electrochemical, and mechanical properties.

Prognostic value of von Willebrand factor in adult patients with congenital heart disease.

OBJECTIVES: von Willebrand factor (vWF) has prognostic value in patients with heart failure (HF) and in those with liver disease. Liver congestion, due to right-sided HF (RHF), is one of the major clinical pathophysiologic manifestations in adults with congenital heart disease (ACHD). The present study's purpose was to clarify the prognostic value of plasma levels of vWF antigen (vWF:Ag) in ACHD. METHODS: We measured vWF:Ag (%) in 382 consecutive patients (20 unrepaired cyanotic ACHD, 172 Fontan patients and 190 ACHD after biventricular repair) and compared the results with the clinical profiles and prognosis. RESULTS: The plasma vWF:Ag level was 130±53 (normal range: 55%-190%), and 48 patients (13%) showed high levels of vWF:Ag (≥190%). Older age, Fontan circulation, higher central venous pressure, lower arterial oxygen saturation and lower plasma levels of albumin were independently associated with high log (vWF:Ag) (p<0.05-0.0001). During the follow-up of 2.4±1.4 years, 15 patients died. High log (vWF:Ag) predicted the all-cause mortality (HR 1.63 per 0.1, 95% CI 1.40 to 1.96, p<0.0001). Specifically, patients with high vWF:Ag (≥165%) had a substantially higher risk of all-cause mortality (HR 56.4, 95% CI 11.4 to 1020, p<0.0001), and this prognostic value was independent of plasma levels of brain-type natriuretic peptide. CONCLUSIONS: High vWF:Ag may reflect RHF severity and related liver dysfunction with a strong prognostic value of all-cause mortality in ACHD. Thus, vWF:Ag might be an excellent biomarker for monitoring ACHD with RHF.

Density and viscosity of liquid ZrO2 measured by aerodynamic levitation technique.

Liquid ZrO2 is one of the most important materials involved in severe accident analysis of a light-water reactor. Despite its importance, the physical properties of liquid ZrO2 are scarcely reported. In particular, there are no experimental reports on the viscosity of liquid ZrO2. This is mainly due to the technical difficulties involved in the measurement of thermo-physical properties of liquid ZrO2, which has an extremely high melting point. To address this problem, an aerodynamic levitation technique was used in this study. The density of liquid ZrO2 was calculated from its mass and volume, estimated based on the recorded image of the sample. The viscosity was measured by a droplet oscillation technique. The density and viscosity of liquid ZrO2 at temperatures ranging from 2753 K to 3273 K, and 3170 K-3471 K, respectively, were successfully evaluated. The density of liquid ZrO2 was found to be 4.7 g/cm 3 at its melting point of 2988 K and decreased linearly with increasing temperature, and the viscosity of liquid ZrO2 was 13 mPa at its melting point.

Si-Based Materials for Thermoelectric Applications.

Si-based thermoelectric materials have attracted attention in recent decades with their advantages of low toxicity, low production costs, and high stability. Here, we report recent achievements on the synthesis and characterization of Si-based thermoelectric materials. In the first part, we show that bulk Si synthesized through a natural nanostructuring method exhibits an exceptionally high thermoelectric figure of merit zT value of 0.6 at 1050 K. In the second part, we show the synthesis and characterization of nanocomposites of Si and metal silicides including CrSi2, CoSi2, TiSi2, and VSi2. These are synthesized by the rapid-solidification melt-spinning (MS) technique. Through MS, we confirm that silicide precipitates are dispersed homogenously in the Si matrix with desired nanoscale sizes. In the final part, we show a promising new metal silicide of YbSi2 for thermoelectrics, which exhibits an exceptionally high power factor at room temperature.

Retraction Note to: Primary Draining Vein Stenting for Obstructive Total Anomalous Pulmonary Venous Connection in Neonates with Right Atrial Isomerism and Functional Single Ventricle Improves Outcome.

The authors have retracted this article [1] because, contrary to the statement in the article, this research did not obtain ethics approval from the National Cerebral and Cardiovascular Center Institutional Review Board prior to submission of the manuscript to Pediatric Cardiology. All authors agree to this retraction.

Cardiovascular profile and biophysical profile scores predict short-term prognosis in infants with congenital heart defect.

AIM: To predict the prognosis of infants with congenital heart disease, accurate prenatal diagnosis of structural abnormality and heart failure are both necessary. The aim of this study was to investigate whether cardiovascular profile (CVP) and biophysical profile (BP) scores are useful for predicting prognosis in infants with congenital heart defect (CHD). METHODS: A retrospective review of singletons prenatally diagnosed with CHD at a tertiary pediatric cardiac center between 2011 and 2015 was undertaken. RESULTS: A total of 202 patients with CHD were analyzed. Perinatal and infant deaths occurred in 16 (7.9%) and 10 cases (5.0%), respectively. Infants with the last CVP score ≤ 5 had 18.7-fold higher perinatal mortality than those with a last CVP score > 5 (P < 0.01). Infants with a last BP score ≤ 6 had 18.7-fold higher perinatal mortality than those with a last BP score > 6 (P < 0.01). Infants with a CVP score decrease in utero had 4.5-fold higher infant mortality than those with an increase or no change (P < 0.01). Multivariate analysis showed that single-ventricle physiology, pre-term birth at <37 weeks of gestation, last CVP score ≤ 5, and last BP score ≤ 6 were independent predictors of perinatal mortality. Single-ventricle physiology and a CVP score decrease were independent predictors of infant mortality. CONCLUSION: CVP and BP scores are useful for predicting perinatal prognosis in infants with CHD. A CVP score decrease in utero is associated with infant mortality, suggesting that serial CVP score assessment may be useful for management planning.

Nanostructured bulk Si for thermoelectrics synthesized by surface diffusion/sintering doping.

Nanostructured bulk silicon (bulk nano-Si) has attracted attention as an advanced thermoelectric (TE) material due to its abundance and low toxicity. However, oxidization will occur easily when bulk nano-Si is synthesized by a conventional method, which deteriorates the TE performance. Various methods to prevent such oxidation have been proposed but they need specific techniques and are thus expensive. Here, we propose a simple and cost-effective method named Surface Diffusion/Sintering Doping (SDSD) to synthesize bulk nano-Si for TEs. SDSD utilizes Si nanoparticles whose surface is coated with a native thin oxide layer. SDSD is composed of two steps, (1) a molecular precursor containing a doping element is added onto the oxide layer of Si nanoparticles and (2) the nanoparticles are sintered into a bulk state. During sintering, the doping element diffuses through the oxide layer forming conductive paths, which results in a high carrier concentration as well as high mobility. Furthermore, owing to the nanostructures, low lattice thermal conductivity (κ lat) is also achieved, which is an ideal situation for TEs. In this study, we show that P-doped bulk nano-Si synthesized by SDSD shows good TE performance due to its high carrier concentration, high carrier mobility, and low κ lat. Since SDSD takes advantage of oxidization, it is cost-effective and suitable for mass production to synthesize bulk nano-Si for TEs.

Prediction of postnatal arrhythmia in fetuses with cardiac rhabdomyoma.

OBJECTIVES: Fetal cardiac rhabdomyomas are rare but well-known to be associated with arrhythmia or conduction abnormalities. However, since in utero electrophysiological information is quite limited, it remains unclear which type of rhabdomyoma will develop arrhythmia after birth. The aim of this study is to identify factors that predict postnatal arrhythmia requiring therapy in fetuses with cardiac rhabdomyoma. STUDY DESIGN: A retrospective review of infants prenatally diagnosed with cardiac rhabdomyoma was performed at our tertiary pediatric cardiac center between 1990 and 2016. Fetal arrhythmia was diagnosed using fetal echocardiography and magnetocardiography. We compared the characteristics of cases with and without antiarrhythmic therapy after birth. Cases without antiarrhythmic therapy after birth consisted of those who had postnatal arrhythmia but did not require antiarrhythmic therapy and those who had no postnatal arrhythmia. RESULTS: A total of 20 fetuses with cardiac rhabdomyoma were included in this study. Ten cases (50%) were confirmed as having tuberous sclerosis after birth. The mean gestational week at diagnosis and delivery were 32.1 ± 2.7 and 37.6 ± 2.8 weeks, respectively. Mean cardiac tumor size in utero was 21 ± 11 mm (range, 7-54 mm) in diameter. Fetal arrhythmia was found in six cases; three resolved in utero with transplacental antiarrhythmic therapy. Postnatal arrhythmia or conduction abnormalities were found in 12 cases; 7 required antiarrhythmic therapy. Cases with antiarrhythmic therapy after birth had larger cardiac tumor in utero than those without therapy (29.6 ± 12.8 mm versus 16.3 ± 5.8 mm, p < .01). Cardiac tumor size >30 mm in diameter predicted postnatal arrhythmia requiring therapy with sensitivity of 57.1% and specificity of 100%. Location and number of cardiac tumor and presence of arrhythmia or conduction abnormalities in utero were similar between the two groups. CONCLUSIONS: Cardiac rhabdomyomas >30 mm in diameter are associated with postnatal arrhythmia requiring therapy regardless of number and location.

Chalcopyrite ZnSnSb2: A Promising Thermoelectric Material.

Ternary compounds with a tetragonal chalcopyrite structure, such as CuGaTe2, are promising thermoelectric (TE) materials. It has been demonstrated in various chalcopyrite systems, including compounds with quaternary chalcopyrite-like structures, that the lattice parameter ratio, c/ a, being exactly 2.00 to have a pseudo-cubic structure is key to increase the degeneracy at the valence band edge and ultimately achieve high TE performance. Considering the fact that ZnSnSb2 with a chalcopyrite structure is reported to have c/ a close to 2.00, it is expected to have multiple valence bands leading to a high p-type zT. However, there are no complete investigations on the high temperature TE properties of ZnSnSb2 mainly because of the difficulty of obtaining a single-phase ZnSnSb2. In the present study, pure ZnSnSb2 samples with no impurities are synthesized successfully using a Sn flux-based method and TE properties are characterized up to 585 K. Transport properties and thermal analysis indicate that the structure of ZnSnSb2 remains chalcopyrite with no order-disorder transition and clearly show that ZnSnSb2 can be made to exhibit a high zT in the low-to-mid temperature range through further optimization.

Amniotic Fluid Natriuretic Peptide Levels in Fetuses With Congenital Heart Defects or Arrhythmias.

BACKGROUND: We have previously demonstrated that umbilical cord plasma natriuretic peptide (NP) levels reflect the severity of heart failure (HF) in fetuses with congenital heart defects (CHD). The aim of this study was to evaluate the significance of amniotic fluid (AF) NP levels in the assessment of HF in fetuses with CHD or arrhythmia. Methods and Results: This was a prospective observational study at a tertiary pediatric cardiac center. A total of 95 singletons with CHD or arrhythmia, and 96 controls from 2012 to 2015 were analyzed. AF concentrations of atrial NP (ANP), B-type NP (BNP) and N-terminal pro-B-type NP (NT-proBNP) at birth were compared with ultrasonographic assessment of fetal HF using the cardiovascular profile (CVP) score. Multivariate analysis showed that a CVP score ≤5 and preterm birth are independently associated with high AF NT-proBNP levels. AF NT-proBNP levels of fetuses with CHD or arrhythmia inversely correlated with CVP score (P for trend <0.01). In contrast, AF concentrations of ANP and BNP were extremely low, and it was difficult to assess the degree of fetal HF based on them. CONCLUSIONS: AF NT-proBNP concentrations increase in stepwise fashion with the severity of HF in fetuses with CHD or arrhythmia; it was the optimal NP for assessing the fetal HF.

Primary Draining Vein Stenting for Obstructive Total Anomalous Pulmonary Venous Connection in Neonates with Right Atrial Isomerism and Functional Single Ventricle Improves Outcome.

For neonates with right atrial isomerism (RAI), functional single ventricle (f-SV), and obstructive total anomalous pulmonary venous connection (TAPVC), primary TAPVC repair (TAPVCR) has a poor outcome. At our hospital, the survival rate at 1 year of such neonates undergoing primary TAPVCR between 1999 and 2010 (TAPVCR group) was 30% (3/10). Most deceased cases suffered from capillary leak syndrome and unstable pulmonary resistance after the surgeries. We sought to determine whether less invasive primary draining vein stenting (DVS) improved the outcome of these neonates. We investigated outcomes in consecutive nine such neonates (median gestational age 38 weeks, birth weight 2.8 kg, females 4) who underwent primary DVS with 6-mm-diameter Palmaz® Genesis® stents at our hospital between 2007 and 2017 (DVS group). Eight patients underwent subsequent surgeries to adjust the pulmonary flow after decreased pulmonary resistance. The survival rate at 1 year after the first interventions in the DVS group improved to 77% (7/9), although there was a difference between the interventional eras of the two groups. Of the seven patients who underwent multiple stent redilations with a larger balloon or additional stenting in other sites until the next stage of surgery at a median age of 8 months, four received a bidirectional Glenn (BDG) shunt and TAPVCR and three underwent TAPVCR, with two of those cases reaching BDG. Less invasive primary DVS improved the outcome of neonates with RAI, f-SV, and obstructive TAPVC, with many reaching BDG. Patient selection to advance toward Fontan is thought to further improve the outcome.

Fetal echocardiographic findings in right pulmonary artery to left atrium communication: a case report and review of the literature.

Right pulmonary artery to left atrium communication (RPALA com) is a fatal congenital heart disease with right-to-left shunting. We present a rare case of RPALA com that was prenatally diagnosed and confirmed by autopsy. We focus on some unique echocardiographic findings for prenatal diagnosis of RPALA com by reviewing our case and the literature. Asymmetric cardiomegaly with a pear sign and dilatation of the pulmonary artery might be useful for screening tests. A larger stalk with the pear sign, high-velocity of shunt flow, and absence of a dilated pulmonary vein might support the prenatal diagnosis of RPALA com.

High wettability of liquid caesium iodine with solid uranium dioxide.

In March 2011, the Fukushima Daiichi Nuclear Power Plant accident caused nuclear fuel to melt and the release of high-volatility fission products into the environment. Caesium and iodine caused environmental contamination and public exposure. Certain fission-product behaviours remain unclear. We found experimentally that liquid CsI disperses extremely favourably toward solid UO2, exhibiting a contact angle approaching zero. We further observed the presence of CsI several tens of micrometres below the surface of the solid UO2 sample, which would be caused by the infiltration of pores network by liquid CsI. Thus, volatile fission products released from molten nuclear fuels with complex internal composition and external structure migrate or evaporate to varying extents, depending on the nature of the solid-liquid interface and the fuel material surface, which becomes the pathway for the released fission products. Introducing the concept of the wettability of liquid chemical species of fission products in contact with solid fuels enabled developing accurate behavioural assessments of volatile fission products released by nuclear fuel.

Cardiovascular profile score as a predictor of acute intrapartum non-reassuring fetal status in infants with congenital heart defects.

OBJECTIVES: To investigate the predictive factors of urgent cesarean delivery (CD) due to acute intrapartum non-reassuring fetal status (NRFS) in infants with congenital heart defects (CHDs). STUDY DESIGN: This was a retrospective review of 199 singletons prenatally diagnosed with a CHD and for whom vaginal delivery was attempted in our institution between 2007 and 2014. A cardiovascular profile (CVP) score was used to assess fetal heart failure. RESULTS: The number of urgent CDs due to NRFS was 37 (18.6%). Fetuses with a CVP score ≤7 were significantly more likely to require urgent CD due to NRFS than those with a CVP score ≥8 (p < 0.001). Infants with right heart defects or biventricular cyanotic heart defects had a significantly higher frequency of urgent CD due to NRFS than those with other types of CHD (p = 0.017). Multivariate analysis showed that a CVP score ≤7, a birth weight <2500 g, and primipara status were significant predictors of urgent CD due to NRFS. CONCLUSIONS: Fetal heart failure, low birth weight, and primipara status were revealed to be independent predictors of urgent CD due to acute intrapartum NRFS in CHD infants. The CVP score may be a useful echocardiographic marker in perinatal management planning.

Comorbid Epilepsy and Developmental Disorders in Congenital Long QT Syndrome With Life-Threatening Perinatal Arrhythmias.

OBJECTIVES: Given the association of long QT syndrome (LQTS) and neurological disorders, we speculated that the more severe LQTS phenotype, perinatal LQTS, would exhibit more frequent comorbid neurodevelopmental anomalies than LQTS without perinatal arrhythmias (nonperinatal LQTS). BACKGROUND: Congenital LQTS with life-threatening perinatal arrhythmias (perinatal LQTS) has a poor life prognosis. METHODS: Twenty-one consecutive LQTS patients diagnosed before 1 year of age at our institution and 3 previously reported perinatal LQTS patients with neurological seizures were enrolled. In total, the clinical course was evaluated in 24 patients. RESULTS: Among 21 infantile LQTS patients, 5 of 6 with perinatal LQTS (83%) were diagnosed with epilepsy and 4 (67%) with developmental disorders, but none with nonperinatal LQTS were. The total development quotient by Kinder Infant Development Scale scores was 17 to 72 (median 67) in 5 epileptic perinatal LQTS. In the 8 perinatal LQTS patients with neurological disorders, including 3 previously reported cases, epileptic seizures occurred at 2 days to 2.5 years of age and 5 had developmental disorders. Mutations in these 8 patients were located in the transmembrane loop of KCNH2, and D3/S4-S5 linker, D4/S4, or the D4/S6 segment of SCN5A. CONCLUSIONS: A high comorbidity of neurodevelopmental anomalies was observed in perinatal LQTS. Mutations in patients with neurological comorbidities were in loci linked to LQTS with a severe cardiac phenotype. These observations indicate the possibility that neurological disorders in perinatal LQTS are manifested as neurological phenotypes associated with severe cardiac phenotypes, while we could not completely exclude another possibility that those were caused by a brain perfusion injury.

Fetal critical aortic stenosis with natural improvement of hydrops fetalis due to spontaneous relief of severe restrictive atrial communication.

We describe a rare case of fetal critical aortic stenosis with spontaneous relief of severe restrictive atrial communication, resulting in complete resolution of hydrops fetalis in utero. Fetal ultrasonography showed hydrops fetalis caused by critical aortic stenosis with a severely restrictive foramen ovale and severe mitral regurgitation at 23 weeks of gestation. Hydrops fetalis, however, spontaneously resolved, showing an obvious increase of flow through the foramen ovale and pulmonary vein at 26 weeks of gestation. The neonate required balloon dilation of the aortic valve and balloon atrioseptostomy immediately after birth and also received bilateral pulmonary artery banding and arterial duct stenting 1 week later. The patient was in good condition after conversion to biventricular circulation via Ross procedure at 8 months old. The present case suggests that atrioseptostomy as a fetal intervention may improve outcome in even a hydropic condition.