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Abstract This case reports describe a rare disease, mid‐aortic syndrome (MAS), that can cause severe heart failure and hypertension in infancy. The typical images, key points of diagnosis, and therapy methods of the disease have also been presented. We report two critical thoracoabdominal aortic coarctation cases in infants aged 2 and 11 months with severe heart failure. The patients were initially misdiagnosed as dilated myocardiopathy, with the correct diagnosis confirmed through imaging. Both patients underwent balloon angioplasty; one patient also had bare‐metal stents implanted. The patient treated with balloon angioplasty alone died after the procedure, whereas the other patient recovered well. In conclusion, careful physical examinations, especially upper and lower extremity blood pressure differences and palpation of upper and lower limb pulses, are critical in unexplained infant heart failure cases. Stent implantation may be a safer and more effective treatment than simple balloon angioplasty in infants with MAS.

A 6-year-old girl was diagnosed with Kawasaki disease and bilateral giant coronary artery aneurysms at four months old and was subsequently referred to our hospital due to chest pain and T wave changes on electrocardiography. After admission, stress myocardial perfusion imaging showed reversible ischemia in multiple areas of the left ventricle. Coronary angiography revealed complete proximal segment occlusion of the left circumflex artery (LCX). The occluded LCX was recanalized by a Gaia 3rd micro-wire successfully passing through the occluded section to the distal end of the LCX, followed by sequential balloon dilation and drug-coated balloon angioplasty. Coronary angiography immediately after post-dilation and one-year follow-up angiography showed that the structure and blood flow of LCX was good. Although percutaneous coronary intervention (PCI) in pediatric patients with Kawasaki disease is limited in practice, PCI remains one of the treatment options for selected patients.

Abstract Background Kawasaki disease (KD) is a medium vessel vasculitis that typically occurs in children aged between 6 months and 5 years. It is extraordinarily rare in the neonatal period. KD-related systemic artery aneurysms (SAAs) have never been reported in neonates. Case presentation A male infant was transferred to our institution for persistent high-grade fever lasting 16 days. Symptoms started at day 14 of life, and he was admitted to a children’s hospital on the second day of fever. Physical examination at the time found no signs suggestive of KD. The only laboratory parameters which were of significance were values suggestive of systemic inflammation. However, his fever persisted and inflammatory markers continued to rise despite 2 weeks of antibiotic therapy. KD as a noninfectious cause of fever was considered when he came to our institution, and echocardiographic findings of left and right medium coronary artery aneurysms (CAAs) confirmed our suspicions. Full-body magnetic resonance angiography also revealed bilateral axillary artery aneurysms. Administration of intravenous gamma globulin resulted in rapid improvement. His fever resolved on the next day and CAAs and SAAs regressed to normal at 6 months and 3 months after diagnosis, respectively. Conclusion This unique case of incomplete KD highlights the importance of considering KD in neonates with unexplained prolonged fever and reinforces the need to remain vigilant for SAAs in KD.

Left posterior fascicular ventricular tachycardia (LPFVT) is extremely rare in neonates. We described a 17-day-old girl with LPFVT who was initially misdiagnosed as supraventricular tachycardia (SVT). Eventually, she was successfully treated by amiodarone infusion followed by oral amiodarone with propranolol for 9 months, and LPFVT spontaneously resolved after a 1-year follow-up. This case report illustrated the basic principles and caveats in differential diagnosis of LPFVT in the neonatal age group. With proper diagnosis and therapy, neonatal LPFVT might regress in the first year of life.

Background: Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare but potentially life-threatening congenital heart defect. A retrospective analysis was carried out to elucidate the surgical outcomes of ALCAPA in infants and children using follow-up echocardiography. Methods: From September 2008 to March 2017, 26 children diagnosed with ALCAPA underwent left coronary re-implantation. All surviving patients received echocardiography during follow-up. Results: The mortality rate after the operation was 11.5%. Before repair, twenty patients (76.9%) presented with left ventricular (LV) dysfunction. The mean Z-score of the preoperative LV end-diastolic diameter was 4.42 ± 2.09. Mitral regurgitation (MR) was present in all patients. Two patients (7.7%), both with mitral valve prolapse, underwent mitral valve repair at the time of ALCAPA repair. Two children required postoperative extracorporeal membrane oxygenation. LV function normalized at a median time of 5.3 months (range: 0.5–36.0 months). The Z-score of the LV end-diastolic diameter decreased simultaneously. The degree of MR gradually decreased in all surviving patients. All patients had patency of the proximal left coronary artery confirmed by echocardiography at the most recent follow-up. Six patients (26.1%) showed supravalvar pulmonary stenosis and seven patients (30.4%) showed right pulmonary stenosis during follow-up. Conclusions: Coronary re-implantation was effective for rebuilding a dual coronary system in patients with ALCAPA and resulted in progressive improved LV function and reduced functional MR. Echocardiography was valuable for evaluating the outcomes. LV function, the degree of MR, and possible complications could be detected with follow-up echocardiography.

In view of nonlinear characteristic of pressure distribution of high viscous materials like coal slurry in slurry pipeline, the paper put forward a kind of modeling method based on BP neural network optimized by quantum genetic algorithm after analysis of relationship of pipeline pressure and main influence factors based on experimental data. The method optimizes weights and thresholds of BP neural network by quantum genetic algorithm, and uses the optimized BP neural network to approximate nonlinear characteristics of the pipeline pressure of coal slurry, then gets mathematical model. The simulation results show that the pressure distribution model of coal slurry pipeline based on optimized BP neural network has good stability, its error is 0.063 2, which can satisfy engineering requirement, and it is better than the model based on BP neural network in optimization time and accuracy.

This case reports describe a rare disease, mid‐aortic syndrome (MAS), that can cause severe heart failure and hypertension in infancy. The typical images, key points of diagnosis, and therapy methods of the disease have also been presented. We report two critical thoracoabdominal aortic coarctation cases in infants aged 2 and 11 months with severe heart failure. The patients were initially misdiagnosed as dilated myocardiopathy, with the correct diagnosis confirmed through imaging. Both patients underwent balloon angioplasty; one patient also had bare‐metal stents implanted. The patient treated with balloon angioplasty alone died after the procedure, whereas the other patient recovered well. In conclusion, careful physical examinations, especially upper and lower extremity blood pressure differences and palpation of upper and lower limb pulses, are critical in unexplained infant heart failure cases. Stent implantation may be a safer and more effective treatment than simple balloon angioplasty in infants with MAS. [ABSTRACT FROM AUTHOR]

Nb3Sn superconductor is of significant interest for applications in constructing high-field magnets beyond the limit of NbTi. However, its critical current density decreases rapidly at high magnetic fields ( > 12 T) and the state-of-the-art level of Nb3Sn superconductors still cannot meet the requirements of the planned future accelerator magnets. The primary flux pinning centers for Nb3Sn wire mainly arise from the grain boundaries (GBs). In the present paper, we theoretically investigate, through time-dependent Ginzburg-Landau theory and with graphics-processing unit parallel technique, the vortex pinning and the critical current density in large-scale polycrystalline Nb3Sn superconductor by varying the pinning potential of GB and grain size at various magnetic fields. Unlike the conventional dot-like pinning systems, it is found that the critical current is not a monotonous function by suppressing the superconductivity of the GBs. The optimal pinning potential of GB for maximum critical current density strongly depends on magnetic fields. Furthermore, we find that the critical current density can be significantly enhanced by reducing grain size at low magnetic fields, while increase of critical current density cannot always be observed at high magnetic fields. Actually, critical current density even decreases by reducing grain size, which depends on the superconductivity of GBs. The findings in the paper provide theoretical foundations to achieve further improvement of Nb3Sn with optimizing the flux pinning. [ABSTRACT FROM AUTHOR]

Ferromagnetic materials will affect not only the electromagnetic response but also the mechanical behaviors of coated conductors. The influence of soft ferromagnetic substrate on magneto-elastic behavior in a superconductor/ferromagnetic (SC/FM) bilayer exposed to a transverse magnetic field is investigated theoretically. The ferromagnetic substrate is regarded as ideal soft magnets with high permeability and small magnetic hysteresis. Due to the composite structure of SC/FM hybrids, magneto-elastic behavior will be subjected to combined effect of equivalent force and flexural moment. Analytical expressions for internal stress and strain components are derived by virtue of a two-dimensional elasticity analysis. It is worth pointing out that the y component of strain has much larger positive value during field ascent, which may result in the delamitation at the interface. Irreversible magnetostrictive behaviors are observed both along x direction and along y direction. For the thickness dependence of magnetostriction, the flexural moment dominates when the SC thickness is small while the equivalent force plays a critical role at higher SC thickness. [ABSTRACT FROM AUTHOR]

In this paper, the critical state Bean model is employed to estimate the effect of the electromagnetic force on the fracture behavior of the superconductor slab. The superconductor slab with an inclined crack is subjected to an applied field. Based on the finite element method, the stress intensity factors are computed for two activation processes, zero field cooling and field cooling. Numerical results obtained show that the crack length and the inclined angle have significant effects on the fracture behavior. Generally, maximum of mode-I stress intensity factor is larger than that of mode-II stress intensity factor. The stress intensity factors analyzed in the paper are useful to learn fracture behavior and mechanical failure of superconductors. [ABSTRACT FROM AUTHOR]

Using time-dependent Ginzburg–Landau formalism, we investigate the multiple reversals of ratchet effects in an unpatterned superconducting strip by the tilted dynamic pinning potential. In the case of collinear sliding potential and Lorentz force, vortices are always confined in the channels induced by sliding potential. However, due to the inclination angle of sliding pinning potential with respect to the Lorentz force, vortices could be driven out of the channels, and unexpected results with multiple reversals of vortex rectifications are observed. The mechanism of multiple reversals of vortex rectifications is explored by analyzing different vortex motion scenarios with increasing ac current amplitudes. The multiple reversals of transverse and longitudinal ratchet effects can be highly controlled by ac amplitude and dynamic pinning velocity. What's more, at certain large current the ratchet effect reaches strongest within a wide range of pinning sliding velocity. [ABSTRACT FROM AUTHOR]

Eucommiae Cortex (EC), a rare, nourishing medicinal herb that is native in China, has good effect in the treatment of hypertension. In this study, we compared tissue distribution of six representative active components of EC extract—genipinic acid (GA), protocatechuic acid (PCA), neochlorogenic acid (NCA), chlorogenic acid (CA), (+)-pinoresinol di-O-β-D-glucopyranoside (PDG), and (+)-pinoresinol 4′-O-β-D-glucopyranoside (PG)—between normal rats and spontaneously hypertensive rats (SHRs). Each rat was intragastrically given EC extract at a dose of 5.4 g/kg. Rats were sacrificed at 10 min, 30 min, 2 h, and 8 h after administration; six rats were sacrificed at each time point. Then, we quickly harvested their major organs, including heart, liver, spleen, lungs, kidneys, and brain. Using ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), we determined the levels of the above mentioned six components in the organs of both types of rats and then analyzed differences in the tissue distribution. The results showed that levels of each component differed between SHRs and the normal group at each time point. As time progressed, the number of organs in which GA distribution in each tissue of SHRs differed from that of the normal group gradually increased: SHRs showed lower GA levels than normal rats. Levels of PG and PDG in both groups at 10 and 30 min were similar. NCA and CA in the SHR group and the normal group at 10 min, 30 min, and 2 h were also similar to some extent. The results indicated that the pathological state of spontaneous hypertension could affect tissue distribution of EC active components in rats. [ABSTRACT FROM AUTHOR]

The strain effect on critical magnetic field in isotropic high-κ superconductors is studied theoretically in this paper. Based on the phenomenological theory, we obtain the critical magnetic field in the presence of the applied strain. The dependence of upper critical magnetic field on the coupling parameters is discussed. The theoretical analysis is in broad agreement with experimental results as the coupling parameters are the linear functions of the strain. Furthermore, according to the assumption, the plot of strain effect on lower critical field is observed as symmetric curve for compressive and tensile strains. The plots also predict that the strain effect on lower critical field is greater in higher-κ superconductors. [ABSTRACT FROM AUTHOR]

We theoretically investigate, through Ginzburg–Landau simulations, the possibility to induce an open circuit voltage in absence of applied current, by dragging superconducting vortices with a dynamic pinning array as for instance that created by a nearby sliding vortex lattice or moving laser spots. Different dynamic regimes, such as synchronous vortex motion or dynamic vortex chains consisting of laggard vortices, can be observed by varying the velocity of the sliding pinning potential and the applied magnetic field. Additionally, due to the edge barrier, significantly different induced voltage is found depending on whether the vortices are dragged along the superconducting strip or perpendicular to the lateral edges. The output voltage in the proposed mesoscopic superconducting dynamo can be tuned by varying size, density and directions of the sliding pinning potential. [ABSTRACT FROM AUTHOR]

Introducing artificial antidots into superconductors is an efficient way to improve the superconducting properties for application. However, besides the pioneering theoretical studies, the fundamental question concerning how many vortices can be trapped by the antidot still needs to be further clarified from an experimental point of view. In this study, by the e-beam lithography, antidots with different sizes and shapes are fabricated in a superconducting Pb film. The vortex distribution at antidots has been directly imaged using the low-temperature scanning Hall probe microscope. A universal scaling behavior is found that the number of trapped vortices mainly depends on the size of the antidots, irrespective of the shape of antidots. The results shed light on the study of vortex pinning at artificial pinning centers, which is important for practical applications. [ABSTRACT FROM AUTHOR]

Vortex rectifications are well known as drifting vortices along an "easy" direction when asymmetric potential is introduced to break the inversion symmetry for the vortex motion. Using the time-dependent Ginzburg–Landau formalism, we show an approach to switch the reversal of vortex ratchets by a dynamic pinning landscape, which is highly tuned by varying the sliding velocity of the dynamic pinning potential and its characteristic sizes and densities. Besides the anticipated positive rectified voltage with an easy vortex motion along the sliding direction of dynamic pinning sites, contrary to intuition, we also observe a negative dc voltage with vortices moving preferentially uphill, i.e., against the sliding direction. The mechanism of such reversal of vortex ratchets is different from previous work, which is revealed based on the dragging effect on the vortex motion by the sliding pinning sites. [ABSTRACT FROM AUTHOR]

We study the degeneracy of the superconducting vortex ground state in a dice lattice of elongated antidots within the Ginzburg-Landau (GL) theory. It is found there are two kinds of unit cells in this dice lattice, namely z6 unit cell where six antibars meet and z3 unit cell where three antibars meet. This can result in more complicated vortex arrangements in the unit cells than that in the kagome lattice. We demonstrate that the vortex patterns at specific fractional magnetic fields can be determined by the local constraints, which presented the ice-like vortex configuration based on the degeneracy rules. This is the reason that the vortex system follows the rule of “two vortices in, one vortex out” or “two vortices out, one vortex in” at each vertex of z3 unit cell. The so-called degeneracy rules are explored by considering nearest-neighbor interaction. Thus, it is possible to realize a rich variety of ice-like vortex configurations in a large area of the sample. [ABSTRACT FROM AUTHOR]

As a model of second-generation high-temperature superconducting (2G HTS) power transmission cable, the effect of soft ferromagnetic (FM) substrate on hysteretic ac loss in a round cable carrying transport current or exposed to radial magnetic field is investigated theoretically. We consider the FM substrates as ideal soft magnets with an infinite permeability, neglecting the magnetic hysteresis. The analytical expressions of field and current distribution around a curved superconductor tape with FM substrate were derived applying the complex-field approach. FM components can strongly influence the ac loss behaviors in a round cable composed of coated conductors. The approximate expressions for ac loss in a round cable at small currents or low fields are obtained. It is shown that at small currents the ac loss QFM in a round cable for FM substrate depended on ac current amplitude ia and central angle θn as , while at low fields ha , the order of which differs significantly from QNM for nonmagnetic (NM) substrate. Additionally, the influence of the central angle as well as tape-width of coated conductors on the ac loss characteristic in a round cable is discussed. The ac loss QFM can be reduced by a suitable tape-width of coated conductor at higher fields as compared with QNM. [ABSTRACT FROM AUTHOR]

Abstract: The strip necking model for strain-hardening materials is studied in this paper, in which the stress distributed over the strip necking zone is assumed to be ultimate stress. The bi-linear stress–strain relation which can model certain features of plastic flow is adopted in this model. The stress and strain fields are calculated based on this model in this paper. The size of the strip necking region is determined by balancing the stress intensity factor due to remote loading with that due to assumed closing forces equal to the ultimate tensile strength of the material distributed over the strip necking zone. It is interesting that the strip necking region size and the crack tip opening displacement depend not only on the remote load, but also the material hardening parameters, which is different from the results of strip yield model. The results agree with experiments well, and the model has wider application. [Copyright &y& Elsevier]

Shone's complex is a rare and severe type of congenital left-sided obstructive lesion of multiple cardiovascular levels. This report aims to present the authors' experience diagnosing atypical Shone's complex using echocardiography. Atypical Shone's complex was diagnosed for 38 consecutive patients (18 boys and 20 girls, ages 1 day to 15 years) using echocardiography. All the diagnoses were confirmed by cardioangiography, surgery, or both. Among the congenital left-sided obstructive lesions, four levels of obstruction coexisted in 3 cases (7.9%), three levels in 10 cases (26.3%), and two levels in 25 cases (65.8%). Supra-annular mitral stenosis caused by a supravalvular mitral ring was diagnosed in 1 case. Mitral valvular stenosis was diagnosed in 24 cases including a parachute mitral valve (4 cases), a double-orifice mitral valve (1 case), and partly fused thickened mitral valvular leaflets (19 cases). Subaortic stenosis was diagnosed in 10 cases including circumferential membranous subaortic stenosis (1 case), tunnel-type subaortic narrowing (2 cases), and asymmetric obstructive fibrous ridge below the aortic valve (7 cases). Aortic stenosis was diagnosed in 25 cases including the bicuspid aortic valve (12 cases), the hypoplasia aortic annulus (3 cases), and partly fused or thickened tri-leaflet aortic valves (10 cases). Supra-aortic stenosis was diagnosed in 6 cases including the localized type (4 cases) and the diffused type (2 cases). Coarctation of the aorta was diagnosed in 26 cases. Of these, focal coarctation was described in 15 cases, long segment coarctation in 7 cases, and dysplastic isthmus and/or descending aorta in 4 cases. Secondary changes in Shone's complex manifested as left atrial dilation (26 cases), left ventricular hypertrophy (26 cases), and pulmonary hypertension (19 cases). Echocardiography plays an important role in the diagnosis of atypical Shone's complex, in comprehensive evaluation of the number, position, morphology, and severity of left-sided obstructions. [ABSTRACT FROM AUTHOR]

Thermomagnetic instabilities are widely observed in bulk superconductors and superconducting (SC) films in form of flux jumps and flux avalanches. Recent experiments demonstrate that the frequent flux jumps can also be observed in superconducting coils. These undesirable flux jumps have a significant impact on coils. However, it is much more difficult to simulate the flux jumps in superconducting coils than bulk superconductors because of the unacceptable number of elements for such complex structures with composite materials. In this paper, we develop a possible scheme to numerically simulate the flux jumps inside the superconducting coils with acceptable computation resources, which allows us to qualitatively study the main characteristics of the thermomagnetic instabilities. Furthermore, we explore the sensitivity of flux jumps inside the superconducting solenoid to various electromagnetic and thermal parameters as well as the ramp rate. Our scheme of numerical simulation may pave an appropriate way to further study the thermomagnetic instabilities inside the various superconducting coils with complex structures. [ABSTRACT FROM AUTHOR]