Ultrafast transient liquid assisted growth of high current density superconducting films

The achievement of high growth rates in YBa₂Cu₃O₇ epitaxial high-temperature superconducting films has become strategic to enable high-throughput manufacturing of long length coated conductors for energy and large magnet applications. We report on a transient liquid assisted growth process capable of achieving ultrafast growth rates (100 nm s⁻¹) and high critical current densities (5 MA cm⁻² at 77 K). This is based on the kinetic preference of Ba-Cu-O to form transient liquids prior to crystalline thermodynamic equilibrium phases, and as such is a non-equilibrium approach. The transient liquid-assisted growth process is combined with chemical solution deposition, proposing a scalable method for superconducting tapes manufacturing. Additionally, using colloidal solutions, the growth process is extended towards fabrication of nanocomposite films for enhanced superconducting properties at high magnetic fields. Fast acquisition in situ synchrotron X-ray diffraction and high resolution scanning transmission electron microscopy (STEM) become crucial measurements in disentangling key aspects of the growth process.

High throughput manufacturing of long length coated conductors requires fast epitaxial growth of high-temperature superconducting films. Here, Soler et al. report an ultrafast growth rates and high critical current densities of YBa₂Cu₃O₇ films using a transient liquid-assisted growth method.

Ultra-fast microwave-assisted reverse microemulsion synthesis of Fe3O4@SiO2 core–shell nanoparticles as a highly recyclable silver nanoparticle catalytic platform in the reduction of 4-nitroaniline

Highly efficient silver catalytic platform Fe₃O₄@SiO₂ core–shell nanoparticles is synthesized via novel microwave-assisted reverse microemulsion fast methodology.

Novel and atypical splicing mutation in a compound heterozygous UNC13D defect presenting in Familial Hemophagocytic Lymphohistiocytosis triggered by EBV infection

Familial Hemophagocytic Lymphohistiocytosis type 3 (FHL3) is a genetic disorder caused by mutations in UNC13D gene, coding the granule priming factor Munc13-4 that intervenes in NK and T cell cytotoxic function. Here we report the case of a 17-month-old girl with prolonged symptomatic EBV infectious mononucleosis and clinical symptoms of hemophagocytic syndrome. In vitro functional analysis pointed to a degranulation defect. The genetic analysis of UNC13D gene identified initially a heterozygous mutation (c.753+1G>T) in the donor splice-site that resulted in exon 9 skipping (maternal allele). Mutations in other genes were considered, but additional analysis of UNC13D cDNA revealed in the paternal allele a heterozygous transition from G to A (c.2448-13G>A) at the 3' acceptor splice-site in intron 25, generating a new acceptor splice-site that leads to a frameshift and a premature STOP codon. Allele specific amplification of the cDNA confirmed the absence of a functional mRNA from the paternal allele. This case illustrates an atypical compound heterozygous UNC13D mutation affecting the RNA splicing that generates a typical FHL3 phenotype.

Nanoscale strain-induced pair suppression as a vortex-pinning mechanism in high-temperature superconductors

Boosting large-scale superconductor applications require nanostructured conductors with artificial pinning centres immobilizing quantized vortices at high temperature and magnetic fields. Here we demonstrate a highly effective mechanism of artificial pinning centres in solution-derived high-temperature superconductor nanocomposites through generation of nanostrained regions where Cooper pair formation is suppressed. The nanostrained regions identified from transmission electron microscopy devise a very high concentration of partial dislocations associated with intergrowths generated between the randomly oriented nanodots and the epitaxial YBa(2)Cu(3)O(7) matrix. Consequently, an outstanding vortex-pinning enhancement correlated to the nanostrain is demonstrated for four types of randomly oriented nanodot, and a unique evolution towards an isotropic vortex-pinning behaviour, even in the effective anisotropy, is achieved as the nanostrain turns isotropic. We suggest a new vortex-pinning mechanism based on the bond-contraction pairing model, where pair formation is quenched under tensile strain, forming new and effective core-pinning regions.

Chemical solution approaches to YBa2Cu3O7_delta-Au nanocomposite superconducting thin films

We explore the feasibility of preparing YBa2CU3O7-Au (YBCO-Au) nanocomposite thin films by chemical solution deposition (CSD). Two approaches were used: (i) A standard in-situ methodology where Au metallorganic salts are added into the precursor solution of YBCO trifluoroacetate (TFA) salts and (ii) a novel approach where stable colloidal solutions of preformed gold nanoparticles (5-15 nm) were homogeneously mixed with TFA-YBCO solutions. A detailed analysis of the microstructure of the films showed that in both cases, there is a strong tendency of gold nanoparticles to migrate to the film surface. However the kinetics of this migration evidences important differences and in the case of preformed nanoparticles their size remains unchanged (a few nanometers) whereas for the in-situ nanocomposites gold ripening leads to large particles (hundreds of nanometers). The grown YBCO-Au films showed good superconducting characteristics (J(c) 2 MA/cm2 at 77 K) but the absence of Au inclusions inside the YBCO matrix explains the fact that no enhancement of vortex pinning was observed.

Airway inflammation in the elite athlete and type of sport

BACKGROUND

The prevalence of asthma and bronchial hyper-responsiveness is greater in elite athletes than in the general population, and its association with mild airway inflammation has recently been reported.

OBJECTIVE

To study the relationship between the type of sport practised at the highest levels of competition (on land or in water) and sputum induction cell counts in a group of healthy people and people with asthma.

MATERIAL AND METHODS

In total, 50 athletes were enrolled. Medical history, results of methacholine challenge tests and sputum induced by hypertonic saline were analysed

RESULTS

Full results were available for 43 athletes, who were classified by asthma diagnosis and type of sport (land or water sports). Nineteen were healthy (10 land and 9 water athletes) and 24 had asthma (13 land and 11 water athletes). Although the eosinophil counts of healthy people and people with asthma were significantly different (mean difference 3.1%, 95% CI 0.4 to 6.2, p = 0.008), analysis of variance showed no effect on eosinophil count for either diagnosis of asthma or type of sport. However, an effect was found for neutrophil counts (analysis of variance: F = 2.87, p = 0.04). There was also a significant correlation between neutrophil counts and both duration of training and bronchial hyper-responsiveness among athletes exposed to water (Spearman's rank correlations, 0.36 and 0.47, p = 0.04 and 0.04, respectively).

CONCLUSIONS

Elite athletes who practice water sports have mild neutrophilic inflammation, whether or not asthma is present, related to the degree of bronchial hyper-reactivity and the duration of training in pool water.

Strong isotropic flux pinning in solution-derived YBa2Cu3O7-x nanocomposite superconductor films

Power applications of superconductors will be tremendously boosted if an effective method for magnetic flux immobilization is discovered. Here, we report the most efficient vortex-pinning mechanism reported so far which, in addition, is based on a low-cost chemical solution deposition technique. A dense array of defects in the superconducting matrix is induced in YBa(2)Cu(3)O(7-x)-BaZrO(3) nanocomposites where BaZrO(3) nanodots are randomly oriented. Non-coherent interfaces are the driving force for generating a new type of nanostructured superconductor. Angle-dependent critical-current measurements demonstrate that a strong and isotropic flux-pinning mechanism is extremely effective at high temperatures and high magnetic fields leading to high-temperature superconductors with record values of pinning force. The maximum vortex-pinning force achieved at 65 K, 78 GN m(-3), is 500% higher than that of the best low-temperature NbTi superconductors at 4.2 K and so a great wealth of high-field applications will be possible at high temperatures.

Lung Function in Cardiac Dysfunction

OBJECTIVE

The alterations in lung function caused by heart failure were first described some decades ago. The advent of new tools for the diagnosis and investigation of heart disease, such as echocardiography, has subsequently made it possible to classify cardiac dysfunction with greater precision. The objective of this study was to analyze and compare a series of lung function and gas exchange variables in patients who had been classified into 4 groups according to type of heart disease as diagnosed by echocardiography.

MATERIALS AND METHOD

Emergency room patients whose main symptom was acute dyspnea caused by cardiac or respiratory disease were included in the study. The final sample comprised 71 patients whose echocardiogram revealed cardiac dysfunction. Spirometry was carried out and resting arterial blood gases measured in this group.

RESULTS

Of the 71 patients with cardiopathy, 31 had systolic dysfunction, 27 diastolic dysfunction, 7 cor pulmonale, and 6 primary valve disease. Spirometry revealed a generally obstructive pattern, more marked in the group with cor pulmonale. Analysis of arterial blood gases revealed slight hypoxemia with normocapnia in all groups, but this was more accentuated in the patients with cor pulmonale and diastolic dysfunction. An analysis of the correlations (Pearson's r) between cardiac and pulmonary variables revealed the statistically significant associations between cardiac mass and other variables to be as follows: forced vital capacity r=0.34 (P=.02), forced expiratory volume in one second r=0.526 (P=.0001), forced expiratory volume in one second as a percentage of predicted r=0.3 (P=.037), and forced midexpiratory flow rate r=0.31 (P=.03). The correlation between left ventricular ejection fraction and PaO2 was r=-0.312 (P=.01); the correlation between left ventricular end-diastolic diameter and PaO2 was r=0.369 (p=.006).

CONCLUSIONS

In patients with cardiac dysfunction, spirometry reveals a generally obstructive pattern, which is more accentuated in patients with right ventricular dysfunction owing to the existence of prior lung disease. The associations found between the cardiac and lung function variables do not help the physician to determine the predominant diagnosis for a patient more precisely or to establish a prognosis.

Separation between the digestive and the respiratory lumina during the human embryonic period: morphometric study along the tracheo-oesophageal septum

An isolated tracheo-oesophageal fistula could be caused by close proximity of the epithelia of both organs (O'Rahilly & Müller, 1984; Kluth et al. 1987) at certain embryonic stages, the most frequent location being the tracheal bifurcation. Thus the relative position and degree of separation between the digestive and the respiratory tubes throughout their development may be relevant to the origin of this anomaly. The aim of this study was to analyse along the different segments of the tracheo-oesophageal septum (TES) where the closest relationship between both lumina occurred and what degree of separation was present at each segment. Computer imaging techniques were applied on cross sections of a graded series of normal human embryos (Carnegie stages (CS) 13-23). In addition, the differentiation of the primitive TES was also studied (from CS 12) by light microscopy. Between CS 13 and 16 both tubes tended to separate (phase of separation), principally at the proximal segments of the laryngopharyngeal and the tracheo-oesophageal portions of the TES. During this phase the separation between the trachea and oesophagus was wider than between the larynx and pharynx. From CS 17 to CS 23 the digestive and respiratory lumina reached their widest separation at different levels of the laryngopharyngeal portion. Below these levels they tended to come closer together, principally at the proximal segment of the tracheo-oesophageal portion, but also at the distal part of the laryngopharyngeal portion. During this phase of approximation they reached their closest relationship at the proximal (CS 17) and the distal (from CS 18) segments of the tracheo-oesophageal portion. When finally the distal segment of the trachea (which includes the bifurcation) comes closest to the oesophagus, the coats of both organs have already undergone an appreciable differentiation. According to these observations, the origin of the most frequent isolated tracheo-oesophageal fistula at the bifurcation region could not be explained from the normal development of the TES.