Viscomagnetoelastic Interactions in a Vortex Array in the Type–II Superconductor

The paper develops considerations on viscomagnetoelastic interactions in a vortex array in a type–II superconductor. It is well known that a magnetic field penetrates such a material along lines called vortices of a special structure. Each of them consists of a core of material in the normal state, i.e. a material in which Ohm’s law works and a surrounding where the supercurrent flows. The mean diameter of a core is called the coherence length. The penetration of the supercurrent outside the core exists in the London penetration depth. Since interactions among the vortices run with the help of the Lorenz force, the vortex field has elastic properties. Moreover, because of the normal state inside the vortex core also the viscosity of that field has been observed. The above situation occurs only between upper and lower magnetic field limits below the critical temperature regarding the phase diagram. The vortex field has a very interesting feature. In the vicinity of the lower magnetic field curve it possesses an ordered (quadratic or triangular) structure. Then going to the upper magnetic field limit that structure is losing its configuration behaving as a fluid. We assume smooth transition from ordered to disordered state althought it is much more complicated in nature. Following the above statements all the “material” coefficients characteristic for the vortex field are also dependent on the magnetic field and temperature. The main aim of the paper is a formulation of the stress – strain constitutive law consisting of the following features:• a coexistence of the ordered and disordered states,• the viscosity of the vortex field,• the dependence of the “material” coefficients related to the vortex field on the magnetic field.An application for YBCO ceramics that deals with the use of the proposed constitutive law in vortex field equations and results coming from that are presented. Numerical calculations concern wave propagation in depinned parallel vortex line field versus magnitude of the applied magnetic field

A stress field in the vortex lattice in the type-II superconductor

Magnetic flux can penetrate a type-II superconductor in the form of Abrikosov vortices (also called flux lines, flux tubes, or fluxons), each carrying a quantum of magnetic flux. These tiny vortices of supercurrent tend to arrange themselves in a triangular and/or quadratic flux-line lattice, which is more or less perturbed by material inhomogeneities that pin the flux lines. Pinning is caused by imperfections of the crystal lattice, such as dislocations, point defects, grain boundaries, etc. Hence, a honeycomb-like pattern of the vortex array presents some mechanical properties. If the Lorentz force of interactions between the vortices is much bigger than the pinning force, the vortex lattice behaves elastically. So we assume that the pinning force is negligible in the sequel and we deal with soft vortices. The vortex motion in the vortex lattice and/or creep of the vortices in the vortex fluid is accompanied by energy dissipation. Hence, except for the elastic properties, the vortex field is also of a viscous character. The main aim of the paper is a formulation of a thermoviscoelastic stress - strain constitutive law consisted of coexistence of the ordered and disordered states of the vortex field. Its form describes an auxetic-like thermomechanical (anomalous) property of the vortex field

Haematological and infectious complications associated with the treatment of patients with congenital cardiac disease: consensus definitions from the Multi-Societal Database Committee for Pediatric and Congenital Heart Disease

A complication is an event or occurrence that is associated with a disease or a healthcare intervention, is a departure from the desired course of events, and may cause, or be associated with, suboptimal outcome. A complication does not necessarily represent a breech in the standard of care that constitutes medical negligence or medical malpractice. An operative or procedural complication is any complication, regardless of cause, occurring (1) within 30 days after surgery or intervention in or out of the hospital, or (2) after 30 days during the same hospitalization subsequent to the operation or intervention. Operative and procedural complications include both intraoperative/intraprocedural complications and postoperative/postprocedural complications in this time interval. The MultiSocietal Database Committee for Pediatric and Congenital Heart Disease has set forth a comprehensive list of complications associated with the treatment of patients with congenital cardiac disease, related to cardiac, pulmonary, renal, haematological, infectious, neurological, gastrointestinal, and endocrinal systems, as well as those related to the management of anaesthesia and perfusion, and the transplantation of thoracic organs. The objective of this manuscript is to examine the definitions of operative morbidity as they relate specifically to the haematological system and to infectious complications. These specific definitions and terms will be used to track morbidity associated with surgical and transcatheter interventions and other forms of therapy in a common language across many separate databases. The MultiSocietal Database Committee for Pediatric and Congenital Heart Disease has prepared and defined a near-exhaustive list of haematological and infectious complications. Within each subgroup, complications are presented in alphabetical order. Clinicians caring for patients with congenital cardiac disease will be able to use this list for databases, quality improvement initiatives, reporting of complications, and comparing strategies for treatmen

Pediatric Cardiac Surgical Patterns of Practice and Outcomes in Europe and China:An Analysis of the European Congenital Heart Surgeons Association Congenital Heart Surgery Database

Background: The European Congenital Heart Surgeons Association (ECHSA) Congenital Heart Surgery Database (CHSD) was founded in 1999 and is open for worldwide participation. The current dataset includes a large amount of surgical data from both Europe and China. Thepurposeofthisanalysisistocomparepatternsof practice and outcomes among pediatric congenital heart defect surgeries in Europe and China using the ECHSA-CHSD. Methods: We examined all European (125 centers, 58,261 operations) and Chinese (13 centers, 23,920 operations) data in the ECHSA-CHSD from 2006-2018. Operative mortality, postoperative length of stay, median patient age and weight were calculated for the ten benchmark operations for China and Europe, respectively. Results: Benchmark procedure distribution frequencies differed between Europe and China. In China, ventricular septal defect repair comprised approximately 70% of procedures, while Norwood operations comprised less than one percent of all procedures. Neonatal cardiac procedures were rare in China overall. For procedures in STAT mortality category 1, Chinese centers had lower operative mortality rates, while procedures in categories 3 and 5 mortality is lower in European centers. Operative mortality over the time period decreased from 3.89% to 1.64% for the whole cohort, with a sharper decline in China. This drop coincides with an increase of submitted procedures over this 13-year-period. Conclusion: Chinese centers had higher program-matic volume of congenital heart surgeries, while European centers have a more complex case mix. Palliation for patients with functionally univentricular heart was performed less commonly in China. These comparison of patterns of practice and outcomes demonstrate opportunities for continuing bidirectional transcontinental collaboration and quality improvement

Pediatric Cardiac Surgical Patterns of Practice and Outcomes in Japan and Europe

Objectives: The Japan Cardiovascular Surgery Database-Congenital section (JCVSD-Congenital) and the European Congenital Heart Surgeons Association (ECHSA) Congenital Heart Surgery Database (CHSD) share the same nomenclature. We aimed at comparing congenital cardiac surgical patterns of practice and outcomes in Japan and Europe using the JCVSD-Congenital and ECHSA-CHSD. Methods and Results: We examined Japanese (120 units, 63,365 operations) and European (96 units, 90,098 operations) data in JCVSD-Congenital and ECHSA-CHSD from 2011 to 2017. Patients' age and weight, periprocedural times, mortality at hospital discharge, and postoperative length of stay were calculated for ten benchmark operations. There was a significantly higher proportion of ventricular septal defect closures and Glenn operations and a significantly lower proportion of coarctation repairs, tetralogy of Fallot repairs, atrioventricular septal defect repairs, arterial switch operations, truncus repairs, Norwood operations, and Fontan operations in JCVSD-Congenital compared to ECHSA-CHSD. Postoperative length of stay was significantly longer following all benchmark operations in JCVSD-Congenital compared to ECHSA-CHSD. Mean STAT mortality score (Society of Thoracic Surgeons European Association for Cardio-Thoracic Surgery mortality score) was significantly higher in JCVSD-Congenital (0.78) compared to ECHSA-CHSD (0.71). Mortality at hospital discharge was significantly lower in JCVSD-Congenital (4.2%) compared to ECHSA-CHSD (6.0%, P < .001). Conclusions: The distribution of the benchmark procedures and age at the time of surgery differ between Japan and Europe. Postoperative length of stay is longer, and the mean complexity is higher in Japan compared to European data. These comparisons of patterns of practice and outcomes demonstrate opportunities for continuing bidirectional transcontinental collaboration and quality improvement

Risk factors for cardiac arrhythmias in children with congenital heart disease after surgical intervention in the early postoperative period

ObjectiveEarly postoperative arrhythmias are a recognized complication of pediatric cardiac surgery.MethodsDiagnosis and treatment of early postoperative arrhythmias were prospectively analyzed in 402 consecutive patients aged 1 day to 18 years (mean 29.5 months) who underwent operation between January and December 2005 at our institute. All children were admitted to the intensive care unit, and continuous electrocardiogram monitoring was performed. Risk factors, such as age, weight, Aristotle Basic Score, cardiopulmonary bypass time, aortic crossclamp time, and use of deep hypothermia and circulatory arrest, were compared. Statistical analysis using the Student t test, Mann–Whitney U test, or Fisher exact test was performed. Multivariate stepwise logistic regression was used to assess the risk factors of postoperative arrhythmias.ResultsArrhythmias occurred in 57 of 402 patients (14.2%). The most common types of arrhythmia were junctional ectopic tachycardia (21), supraventricular tachycardia (15), and arteriovenous block (6). Risk factors for arrhythmias, such as lower age (P = .0041⁎), lower body weight (P = .000001⁎), higher Aristotle Basic Score (P = .000001⁎), longer cardiopulmonary bypass time (P = .000001⁎), aortic crossclamp time (P = .000001⁎), and use of deep hypothermia and circulatory arrest (P = .0188⁎), were identified in a univariate analysis. In the multivariate stepwise logistic regression, only higher Aristotle Basic Score was statistically significant (P = .000003⁎) compared with weight (P = .62) and age (P = .40); in the cardiopulmonary bypass group, only longer aortic crossclamp time was statistically significant (P = .007⁎).ConclusionLower age, lower body weight, higher Aristotle Basic Score, longer cardiopulmonary bypass time, aortic crossclamp time, and use of deep hypothermia and circulatory arrest are the risk factors for postoperative arrhythmias. Junctional ectopic tachycardia and supraventricular tachycardia were the most common postoperative arrhythmias

On-Pump vs Off-Pump coronary artery bypass surgery in atrial fibrillation : analysis from the polish national registry of cardiac surgery procedures (KROK)

BackgroundNo single randomized study has ever before addressed the safety of On-Pump coronary artery bypass grafting (CABG) vs Off-Pump CABG in the setting of atrial fibrillation (AF) and data from small observational samples remain inconclusive.Methods and findingsProcedural data from KROK (Polish National Registry of Cardiac Surgery Procedures) were retrospectively collected. Of initial 188,972 patients undergoing CABG, 7,913 presented with baseline AF (76.0% men, mean age 69.1±8.2) and underwent CABG without concomitant valve surgery between 2006-2019 in 37 reference centers across Poland. Mean follow-up was 4.7±3.5 years (median 4.3 IQR 1.7-7.4). Cox proportional hazards models were used for computations. Of included patients, 3,681 underwent On-Pump- (46.52%) as compared to 4,232 (53.48%) who underwent Off-Pump CABG. Patients in the latter group less frequently were candidates for complete revascularization (PConclusionsOff-Pump CABG offered 30-day survival benefit to patients undergoing CABG surgery and presenting with underlying AF. On-Pump CABG was associated with significantly improved survival at long term

Balonowa angioplastyka we wrodzonej i pooperacyjnej koarktacji aorty &#8212; kilkuletnie obserwacje własne

Wstęp: Celem pracy jest przedstawienie doświadczenia autorów w interwencyjnym leczeniu wrodzonej i pooperacyjnej koarktacji aorty. Materiał i metody: Badania przeprowadzono w grupie 20 dzieci z wrodzoną koarktacją aorty (w wieku 95,75 &plusmn; 71,78 miesiąca; śr. 114 miesięcy, przedział wieku: 11 dni &#8211; 18 lat) i 26 dzieci z pooperacyjną koarktacją (w wieku 47,72 &plusmn; 63,83 miesiąca, śr. 8 miesięcy, przedział wieku: 28 dni &#8211; 16 lat). Zabiegi wykonywano w znieczuleniu ogólnym, z dostępu od strony tętnicy udowej. Średnica balonu nie przekraczała średnicy aorty zstępującej na poziomie przepony. Wyniki: W grupie pacjentów z wrodzoną koarktacją aorty bezpośredni gradient skurczowy przez miejsce zwężenia w grupie 20 pacjentów obniżył się z 38,27 &plusmn; 18,76 mm Hg do 14,09 &plusmn; 14,89 mm Hg (p < 0,001). Trzy noworodki i dwoje niemowląt w wieku poniżej 6 miesiąca życia zakwalifikowano do zabiegu angioplastyki z powodu ciężkiego stanu ogólnego (u 2 z nich ponadto odnotowano hipoplazję łuku poprzecznego). U 3 z nich wynik bezpośredni i w okresie ponad 12-miesięcznej obserwacji był dobry. U pozostałych 2 z hipoplazją łuku poprzecznego w kilka miesięcy później wykonano zabieg operacyjny z dobrym efektem. Spośród 15 pacjentów > 1 rż. u 8 (53,33%) wynik angioplastyki był dobry - u tych chorych nie odnotowano nadciśnienia tętniczego, nie było również konieczne leczenie. U jednego pacjenta po nieskutecznej angioplastyce założono z dobrym efektem hemodynamicznym stent CP. Trzech chorych z hipoplazją cieśni jest w trakcie cyklu kolejnych angioplastyk, stopniowo przygotowujących ścianę aorty do założenia stentu. U 3 pacjentów > 10 rż. wystąpił tętniak aorty i w efekcie został założony stent pokryty (covered stent). W grupie pacjentów z pooperacyjną koarktacją aorty bezpośredni gradient skurczowy przez miejsce zwężenia obniżył się z 42,52 &plusmn; 17,96 do 15,01 &plusmn; 14,91; p < 0,001. Z grupy 26 osób u 22 (84,61%) efekt balonowej angioplastyki był dobry. U 20 pacjentów nie jest konieczne stosowanie leków hipotensyjnych, u 2 nadciśnienie tętnicze jest w pełni kontrolowane jednym lekiem. U 4 osób (15,38%) z powodu nieefektywnej angioplastyki założono stent, uzyskując dobry efekt hemodynamiczny. Wnioski: We wrodzonej koarktacji aorty leczenie interwencyjne jest alternatywne do leczenia chirurgicznego. U noworodków i niemowląt decyzję o wykonaniu angioplastyki balonowej powinno się podejmować indywidualnie w zależności od stanu pacjenta: angioplastyka balonowa wrodzonej koarktacji aorty bez towarzyszącej hipoplazji łuku u pacjentów w wieku powyżej roku jest metodą skuteczną; angioplastyka balonowa wrodzonej koarktacji aorty u pacjentów w wieku ponad 10 lat może spowodować wystąpienie tętniaka aorty; angioplastyka balonowa skrajnie ciasnej koarktacji aorty może być pierwszym etapem przygotowania ściany aorty do założenia stentu; angioplastyka balonowa pooperacyjnej koarktacji aorty jako leczenie z wyboru jest metodą bezpieczną i skuteczną. (Folia Cardiol. 2004; 11: 205&#8211;211