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SiC/SiC composites are the ideal candidates for hot-end components in aerospace and other high-tech fields. In recent years, as one type of material with simple structures, mini-composites have been widely used to study or initially verify the properties of ceramic matrix composites (CMC). Nevertheless, attentions were rarely paid on the influence of strain rate on the mechanical properties of mini-composites. In this study, based on mini-SiC/SiC composites, we investigated the effect of the strain rate on their tensile strength, initial tensile modulus, Weibull modulus, and fracture work. Furthermore, the underlying mechanisms were discussed and the exact constitutive model of the as-prepared mini-SiC/SiC composites was constructed according to the Michaelis-Menten and generalized linear models. This work can fill the gaps in the CMC research in some degree and provide a preliminary theoretical basis for the formulation of tensile properties test standards of mini-composites.

Background The aim of this study was to investigate the feasibility of lung ultrasound in the diagnosis of neonatal respiratory distress syndrome (NRDS) in preterm infants. Methods One hundred and nine preterm infants were prospectively recruited. Three ultrasound diagnostic criteria were developed to diagnose preterm infants with NRDS: (A) thickened or not smooth pleural line, part of the lung field shows diffuse ‘B-line’ sign or alveolar-interstitial syndrome (AIS); (B) thickened or not smooth pleural line, all lung fields show AIS, signifying the ‘white lung’ sign; (C) thickened or rough pleural line, ‘white lung’ sign and ‘lung consolidation’ sign can be observed in any lung field. Results The sensitivity and negative predictive value of NRDS in preterm infants with diagnostic criteria A were 100%, but the specificity and positive predictive value were 67.95 and 55.36%, respectively. The specificity and positive predictive value of diagnostic criteria B and C were 100%, while the 95% CI of diagnostic criteria B was narrower than diagnostic criteria C. The sensitivity and negative predictive value of diagnostic criteria B were higher than that of diagnostic criteria C. Of the 31 NRDS cases, 15 cases had severe NRDS and the other 16 did not have severe NRDS. Conclusion Thickened or rough pleural line with white lung sign is an important characteristic for the diagnosis of NRDS by lung ultrasound. White lung sign combined with the lung consolidation sign had high diagnostic efficacy when distinguishing severe NRDS from not severe NRDS.

Precursor infiltration and pyrolysis (PIP) and chemical vapor infiltration (CVI) were used to fabricate SiC/SiC composites on a four-step 3D SiC fibre preform deposited with a pyrolytic carbon interface. The effects of fabrication processes on the microstructure and mechanical properties of the SiC/SiC composites were studied. Results showed the presence of irregular cracks in the matrix of the SiC/SiC composites prepared through PIP, and the crystal structure was amorphous. The room temperature flexural strength and modulus were 873.62 MPa and 98.16 GPa, respectively. The matrix of the SiC/SiC composites prepared through CVI was tightly bonded without cracks, the crystal structure had high crystallinity, and the room temperature bending strength and modulus were 790.79 MPa and 150.32 GPa, respectively. After heat treatment at 1300 °C for 50 h, the flexural strength and modulus retention rate of the SiC/SiC composites prepared through PIP were 50.01% and 61.87%, and those of the composites prepared through CVI were 99.24% and 96.18%, respectively. The mechanism of the evolution of the mechanical properties after heat treatment was examined, and the analysis revealed that it was caused by the different fabrication processes of the SiC matrix. After heat treatment, the SiC crystallites prepared through PIP greatly increased, and the SiOxCy in the matrix decomposed to produce volatile gases SiO and/or CO, ultimately leading to an increase in the number of cracks and porosity in the material and a decrease in the material load-bearing capacity. However, the size of the SiC crystallites prepared through CVI hardly changed, the SiC matrix was tightly bonded without cracks, and the load-bearing capacity only slightly changed.

Substantial progress has been made in the standardization of nomenclature for paediatric and congenital cardiac care. In 1936, Maude Abbott published her Atlas of Congenital Cardiac Disease, which was the first formal attempt to classify congenital heart disease. The International Paediatric and Congenital Cardiac Code (IPCCC) is now utilized worldwide and has most recently become the paediatric and congenital cardiac component of the Eleventh Revision of the International Classification of Diseases (ICD-11). The most recent publication of the IPCCC was in 2017. This manuscript provides an updated 2021 version of the IPCCC.The International Society for Nomenclature of Paediatric and Congenital Heart Disease (ISNPCHD), in collaboration with the World Health Organization (WHO), developed the paediatric and congenital cardiac nomenclature that is now within the eleventh version of the International Classification of Diseases (ICD-11). This unification of IPCCC and ICD-11 is the IPCCC ICD-11 Nomenclature and is the first time that the clinical nomenclature for paediatric and congenital cardiac care and the administrative nomenclature for paediatric and congenital cardiac care are harmonized. The resultant congenital cardiac component of ICD-11 was increased from 29 congenital cardiac codes in ICD-9 and 73 congenital cardiac codes in ICD-10 to 318 codes submitted by ISNPCHD through 2018 for incorporation into ICD-11. After these 318 terms were incorporated into ICD-11 in 2018, the WHO ICD-11 team added an additional 49 terms, some of which are acceptable legacy terms from ICD-10, while others provide greater granularity than the ISNPCHD thought was originally acceptable. Thus, the total number of paediatric and congenital cardiac terms in ICD-11 is 367. In this manuscript, we describe and review the terminology, hierarchy, and definitions of the IPCCC ICD-11 Nomenclature. This article, therefore, presents a global system of nomenclature for paediatric and congenital cardiac care that unifies clinical and administrative nomenclature.The members of ISNPCHD realize that the nomenclature published in this manuscript will continue to evolve. The version of the IPCCC that was published in 2017 has evolved and changed, and it is now replaced by this 2021 version. In the future, ISNPCHD will again publish updated versions of IPCCC, as IPCCC continues to evolve.

The active oxidation of C/C composites at high temperature is a great obstacle for its application. In this study, a method of preparing SiC/Si–ZrB2–CrSi2/SiC multilayer oxidation-resistant coating for C/C composites by combining preoxidation and chemical vapor deposition (CVD) was proposed, and the results show that the coating has excellent oxidation resistance at 1473 K, 1573 K and 1673 K. Moreover, based on the uniform deformation model, the track of phases transition, lattice strain and internal stress for the protection/failure mechanisms at different temperatures/time were investigated by the agents of strain compatibility and stress distribution soured from XRD and Raman spectra.

A carbon/carbon (C/C)–Cu composite reinforced by novel carbon fiber 2.5D-braided preforms was fabricated through pressureless infiltration technique (PLI). The microstructure of the developed composite was characterized by scanning electron microscopy, X-ray diffraction, and energy dispersive spectroscopy. The mechanical, tribological, and electrical properties of the C/C–Cu composite were compared with those of a C/C composite and a carbon/copper (C/Cu) contact strip material. Results showed that the proposed composite formed an excellent network conduction structure. Moreover, the composite exhibited a high flexural strength of 215 MPa, excellent compression strength of 324 MPa, and a particularly low electrical resistivity of 0.63 μΩm, validating its advantages over the C/Cu composite strip in terms of mechanical and electrical properties. The component phases (TiC) of the C/C–Cu composite formed an excellent interconnected structure, which stiffened the interface between the Cu alloy and the pyrocarbon matrix and resulted in excellent mechanical and electrical properties. The friction coefficients of the C/C, C/C–Cu, and C/Cu composites were 0.152, 0.169, and 0.062, respectively. The C/Cu composite exhibited the worst mechanical and electrical performance despite achieving the lowest friction coefficient. Thus, the C/C–Cu composite is a promising new type of sliding electrical contact material.

Background: Ebstein’s anomaly (EA) has various spectrums in clinical and anatomic features. This study aimed to report the experience of two-dimensional intraoperative transesophageal echocardiography (2D-ITEE) during the EA surgery and to analyze the characteristics of the tricuspid valve (TV) by comparing the data from 2D-ITEE with the results from the surgery. Methods: 2D-ITEE data of 164 patients with EA who were operated in the First Hospital of Tsinghua University between July 2004 and April 2014 were retrospectively analyzed in this study. 2D-ITEE was applied in all patients. Downward displacement distances were measured, and the numbers of downward displacement or absent leaflets were compared with that of the surgery and with that of the two-dimensional-transthoracic echocardiogram (2D-TTE). Data comparison was performed using the Chi-square test. Results: The anterior leaflet partial or total downward displacement was 37.76 ± 17.50 mm in 54 cases, absent in one patient; septal leaflet downward displacement was 29.07 ± 12.34 mm in 134 cases, absent in 17 cases; and posterior leaflet downward displacement was 43.18 ± 19.16 mm in 115 cases, absent in 34 cases. Statistically, there was no significant difference between the results from 2D-ITEE and that of 2D-TTE. The consistency rates of 2D-ITEE with operation for septal and posterior leaflets were 93.2% and 96.1%, respectively, while the rate for anterior was only 40.1%, which was significantly different. Color Doppler flow image showed severe regurgitation in 150 cases and moderate in 14 cases. After surgical correction, moderate regurgitation of TV was found in 58 cases with 2D-ITEE, repair was performed again until the effect was satisfied. No complication occurred relating to the use of 2D-ITEE. Conclusions: 2D-ITEE could help diagnose anterior leaflet, evaluate the effect of TV repair, increase operational success rate, and reduce complication. Key words: Ebstein’s Anomaly; Echocardiography; Two-dimensional-transesophageal Echocardiography

This study extends the state of the art of deep learning convolutional neural network (CNN) to the classification of video images of echocardiography, aiming at assisting clinicians in diagnosis of heart diseases. Specifically, the architecture of neural networks is established by embracing hand-crafted features within a data-driven learning framework, incorporating both spatial and temporal information sustained by the video images of the moving heart and giving rise to two strands of two-dimensional convolutional neural network (CNN). In particular, the acceleration measurement along the time direction at each point is calculated using dense optical flow technique to represent temporal motion information. Subsequently, the fusion of both networks is conducted via linear integrations of the vectors of class scores obtained from each of the two networks. As a result, this architecture maintains the best classification results for eight viewpoint categories of echo videos with 92.1% accuracy rate whereas 89.5% is achieved using only single spatial CNN network. When concerning only three primary locations, 98% of accuracy rate is realised. In addition, comparisons with a number of well-known hand-engineered approaches are also performed, including 2D KAZE, 2D KAZE with Optical Flow, 3D KAZA, Optical Flow, 2D SIFT and 3D SIFT, which delivers accuracy rate of 89.4%, 84.3%, 87.9%, 79.4%, 83.8% and 73.8% respectively.

A novel graphene modified high-temperature resistant adhesive for bonding carbon/carbon composites was developed. The effects of graphene content on the mechanical properties, thermal conductivities and braking properties of the carbon/carbon joints were studied. When the graphene content in the adhesive was 1.5 wt%, the specimens possessed the bonding strength of 13.2 MPa and the thermal conductivity of 23.89 W/(m•k), which were 63.09% and 145.03% higher than those of 0.0 wt%, respectively, and 24.38% and 64.53% higher than those of 5.0 wt%, respectively. The excellent properties were attributed to the uniform dispersion of graphene in the adhesive matrix, which could effectively reduce the stress concentration and provide a fast heat conductivity network chain. The adhesive properties also had an obvious influence on the braking performance. Finite element analysis considered that the main reason for the difference in braking performance was that the temperature and field distribution on the friction surface were affected by the thermal conductivity of the adhesive.

Persistent fifth aortic arch (PFAA) is one of the rarest congenital anomalies. We report a seven-month-old male with PFAA with upper arch interruption and lower arch coarctation diagnosed by echocardiogram and multidetector computed tomography.

We developed a simple strategy for designing a sensitive electrochemical stripping voltammetric sensor for organophosphate pesticides (OPs) based on solid-phase extraction (SPE) using nanosized Pt intercalated Ni/Al layered double hydroxides (labeled as NanoPt-LDHs). By assembling NanoPt with LDHs together, the resulting NanoPt-LDHs are highly efficient to capture OPs. It dramatically facilitates the enrichment of OPs onto their surface and realizes the sensitive stripping voltammetric detection of methyl parathion (MP) as a model of OPs. The stripping analysis shows highly linear over MP concentration ranges of 0.001–0.15 and 0.3–1.0 μg mL−1 with a detection limit of 0.6 ng mL–1 (S/N=3). The combination of NanoPt, LDHs, SPE, and square-wave voltammetry (SWV) provides a fast, simple, and sensitive electrochemical method for OPs. Keywords: Stripping voltammetric analysis, Layered double hydroxides, Solid-phase extraction, Methyl parathion, NanoPt

We developed a simple strategy for designing a highly sensitive electrochemical biosensor for organophosphate pesticides (OPs) based on acetylcholinesterase (AChE) immobilized onto Au nanoparticles-polypyrrole nanowires composite film modifid glassy carbon electrode (labeled as AChE-Au-PPy/GCE). Where, the generated Au nanoparticles (AuNPs) were homogenously distributed onto the interlaced PPy nanowires (PPy NWs) matrix, constructing a three-dimensional porous network. This network-like nanocomposite not only provided a biocompatible microenvironment to keep the bioactivity of AChE, but also exhibited a strong synergetic effect on improving the sensing properties of OPs. The combination of AuNPs and PPyNWs greatly catalyzed the oxidation of the enzymatically generated thiocholine product, thus increasing the detection sensitivity. On the basis of the inhibition of OPs on the enzymatic activity of AChE, the conditions for OPs detection were optimized by using methyl parathion as a model OP compound. The inhibition of methyl parathion was proportional to its concentration ranging from 0.005 to 0.12 and 0.5 to 4.5 microgmL(-1). The detection limit was 2 ngmL(-1). The developed biosensor exhibited good reproducibility and acceptable stability. This study provides a new promise tool for analysis of organophosphate pesticides.

A novel hybrid bifunctional sensing platform for simultaneous determination of NO and O2 has been developed, whereby hematite nanotubes are immobilized into the chitosan matrix onto a gold electrode (labeled as HeNTs-Chi/Au). The HeNTs distributed in porous-structured chitosan matrix not only offer abundant active sites for bifunctional sensing of NO and O2, but also facilitate oxidation of NO and reduction of O2 dramatically. Straight calibration curves are achieved in analyte concentration ranges of 5.0 × 10−8 to 1.25 × 10−6 mol L−1 for NO and 2.5 × 10−7 to 6.0 × 10−6 mol L−1 for O2. Also, the detection limits are low of 8.0 × 10−9 mol L−1 for NO and 5.0 × 10−8 mol L−1 for O2. Such an efficient bifunctional sensor for NO and O2 offers great potential in quantitation of NO levels in biological and medical systems, since NO level is highly regulated by various reactive oxygen species. Keywords: Bifunctional sensor, Hematite nanotubes, Chitosan, Nitric oxide, Oxygen

This work reports on a novel chitosan–hematite nanotubes composite film on a gold foil by a simple one-step electrodeposition method. The hybrid chitosan–hematite nanotubes (Chi–HeNTs) film exhibits strong electrocatalytic reduction activity for H2O2. Interestingly, two electrocatalytic reduction peaks are observed at −0.24 and −0.56 V (vs SCE), respectively, one controlled by surface wave and the other controlled by diffusion process. The Chi–HeNTs/Au electrode shows a linear response to H2O2 concentration ranging from 1 × 10−6 to 1.6 × 10−5 mol L−1 with a detection limit of 5 × 10−8 mol L−1 and a sensitivity as high as 1859 μA μM−1 cm−2. Keywords: Hematite nanotubes, Chitosan, Hydrogen peroxide, One-step electrodeposition, Biosensing

Echocardiograms routinely sample pulmonary regurgitation signals from which it is possible to measure end diastolic gradients; these correlate with pulmonary artery diastolic pressures.We performed echocardiograms in 741 ambulatory adults with coronary artery disease who were recruited for the Heart and Soul Study. We compared indicators of cardiac status among individuals with normal (0-5.0 mm Hg) and elevated (5.0 mm Hg) end diastolic pulmonary regurgitation (EDPR) gradients.Of the 481 participants with measurable EDPR gradients, 21% had elevated EDPR gradients (5.0 mm Hg). EDPR gradients5.0 mm Hg were associated with higher New York Heart Association functional class (P = .002), higher brain natriuretic peptide (P = .002), fewer metabolic equivalents achieved on treadmill testing (P0.001), and higher left ventricular mass (P0.001). The EDPR gradient5.0 mm Hg had a sensitivity of 25% (95% confidence interval 20-30%) and a specificity of 86% (80-91%) for detecting at least one of the following: systolic dysfunction, diastolic dysfunction, or abnormal wall motion score. The EDPR gradient5.0 mm HG was statistically equivalent to the tricuspid regurgitation (TR) gradient30 mm Hg in terms of diagnostic value (area under the receiver operating characteristic curve equaled 0.58 for each test). The EDPR gradient increased the yield of pulmonary artery pressures from 61% (TR gradient alone) to 84% (P.0001).The EDPR gradient provides valuable information independent of the TR gradient in evaluating pulmonary artery pressures and cardiac dysfunction.

Focused abdominal ultrasonography (US) has been introduced in Europe as a method to evaluate blunt abdominal trauma. The main focus of the examination is detection of free fluid in the abdomen secondary to injury of the abdominal organs. The examination takes only a few minutes to perform. In the authors' experience, trauma patients in unstable condition and in whom significant free fluid is detected are immediately taken to the operating room for surgical exploration without undergoing computed tomographic (CT) correlation. The authors have also used US to identify the specific site of organ injury. Injuries to solid organs such as the liver, spleen, and kidney that are identified with US usually appear heterogeneous or hyperechoic. A hematoma surrounding the injured organ may appear echogenic or hypoechoic. However, pitfalls of focused abdominal US for trauma include failure to show contained solid-organ injuries; injuries to the diaphragm, pancreas, and adrenal gland; and some bowel injuries. Thus, negative findings at US do not exclude an intraperitoneal injury, and close clinical observation or CT is warranted.

UNLABELLED We introduce our surgical experience in treating recurrent aortic coarctation or coarctation associated with intracardiac abnormalities, which is difficult to manage. Four patients underwent the operation with hypothermic cardiopulmonary bypass. During the surgery, the posterior pericardium was opened and the thoracic aorta was dissected and sidebiting clamped, and an end-to-side anastomosis of the artificial graft to the descending aorta was performed. The graft was passed in between the inferior vena cava and the inferior right pulmonary vein and posterior to the pericardium. After that, the aorta was clamped and intracardiac repair was finished. Then the proximal artificial graft was anastomosed to the right side of the ascending aorta with heart beating. All patients recovered smoothly. There was no early or late death, without bleeding or other complications after operation. CONCLUSION "Complex coarctation" can be treated with ascending-to-descending aortic bypass via posterior pericardium and satisfied result can be achieved.

Echocardiography plays an important part in diagnostic aid in cardiology. During an echocardiogram exam images or image sequences are usually taken from different locations with various directions in order to comprehend a comprehensive view of the anatomical structure of the 3D moving heart. The automatic classification of echocardiograms based on the viewpoint constitutes an essential step in a computer-aided diagnosis. The challenge remains the high noise to signal ratio of an echocardiography, leading to low resolution of echocardiograms. In this paper, a new synergy is proposed based on well-established algorithms to classify view positions of echocardiograms. Bags of Words (BoW) are coupled with linear SVMs. Sparse coding is employed to train an echocardiogram video dictionary based on a set of 3D SIFT descriptors of space-time interest points detected by a Cuboid detector. Multiple scales of max pooling features are applied to representat the echocardiogram video. The linear multiclass SVM is employed to classify echocardiogram videos into eight views. Based on the collection of 219 echocardiogram videos, the evaluation is carried out. The preliminary results exhibit 72% Average Accuracy Rate (AAR) for the classification with eight view angles and 90% with three primary view locations.

This paper considers a new type of 5-axis machine tool which is used to cut superalloy blades specially. Referring to this new structure system, this study presents modal simulation in detail to calculate the structure vibration resistance. The modal simulation include building suitable finite element models, considering boundary constraints and interpreting results. The physical impact test of prototype is conducted to validate the simulation results. The modal simulation also reveals that some important partial characteristics that affects the structure performance are ignored in the physical test data. The validated model can be used to complement the experimental test.

A sensitive electrochemical stripping voltammetric biosensor is designed for organophosphate pesticides (OPs) based on solid-phase extraction (SPE) using Ni/Al layered double hydroxides (LDHs) modified glassy carbon electrode (labeled as Ni/Al-LDHs/GCE). The Ni/Al-LDHs as the host are highly efficient to capture OPs, which dramatically facilitates the enrichment of nitroaromatic OPs onto their surface and realizes the stripping voltammetric detection of OPs. The stripping voltammetric performances of methyl parathion (MP) intercalated into LDHs were evaluated by cyclic voltammetric and square-wave voltammetric (SWV) analysis. The combination of the host–guest supramolecular structure, SPE, and stripping voltammetry provides a fast, simple, and sensitive electrochemical method for detecting nitroaromatic OPs by using MP as a model. The stripping analysis is linear over the MP concentration ranges of 0.001–0.1 and 0.2–1.0 μg mL−1 with a detection limit of 0.6 ng mL−1 (S/N = 3). The developed biosensor exhibits good reproducibility and acceptable stability. This study offers a new promising protocol for OPs analysis.

To assess the accuracy of emergency abdominal ultrasonography (US) in the detection of both hemoperitoneum and parenchymal organ injury in children.Imaging findings were recorded prospectively in 744 consecutive children who underwent emergency US from January 1995 to October 1998; free fluid and parenchymal abnormalities of specific organs were also noted. Patients with intraabdominal injuries were identified retrospectively. Computed tomographic (CT) findings, intraoperative findings, and clinical outcome were compared with the initial US findings. Sensitivity, specificity, and positive and negative predictive values were calculated for patients who underwent CT, laparotomy, or both after US.Seventy-five (10%) of 744 patients had intraabdominal injuries, and US depicted free fluid in 42 of them. US had 56% sensitivity, 97% specificity, 82% positive predictive value, and 91% negative predictive value for detection of hemoperitoneum alone. US helped identify parenchymal abnormalities that corresponded to actual organ injury without accompanying free fluid in nine patients (12%). Inclusion of identification of parenchymal organ injury at US increased the sensitivity of US to 68%, with an accuracy of 92%.US for blunt abdominal trauma in children is highly accurate and specific, but moderately sensitive, for detection of intraabdominal injury.

Objective We report the results of surgical treatment of Ebstein anomaly during a 10-year period, especially with an anatomic repair technique that restores to near normal anatomic and physiologic function of the tricuspid valve and the right ventricle. Methods Between December 1997 and December 2006, 83 consecutive patients aged 9 months to 52 years underwent operation for Ebstein anomaly. Among them, 78 underwent the anatomic repair technique (male 39). Tricuspid incompetence was moderate in 22 patients and severe in 56 patients. The main surgical technique includes excision of the atrialized right ventricle, detachment and repair of the leaflet, transposition of the leaflet, and anulus plication of the tricuspid valve. In some patients in whom the septal leaflet was severely hypoplastic or absent, a new leaflet was created with autologous pericardium. Biventricular repair was not performed in 5 patients with very severely hypoplastic tricuspid valves and poor right ventricular function. Results All patients survived and recovered uneventfully. For the 78 patients who underwent anatomic repair, postoperative echocardiography showed that tricuspid incompetence disappeared in 65 patients and was mild in 13 patients. Right ventricular function was good. Patients have been doing well during a mean follow-up of 46 months (2 months to 9 years). The latest follow-up echocardiograms showed that tricuspid incompetence was eliminated in 55 patients and was mild in 17, moderate in 3, and severe in 3. The 5 patients with a total cavopulmonary connection procedure and one-and-one-half-ventricle correction procedure are also doing well. Conclusions Satisfactory early and midterm results can be achieved with the anatomic repair technique to correct Ebstein anomaly. Tricuspid valve replacement can be avoided in most patients.