Publications by authors named "Pressley L"

The quantum limit in a Fermi liquid, realized when a single Landau level is occupied in strong magnetic fields, gives rise to unconventional states, including the fractional quantum Hall effect and excitonic insulators. Stronger interactions in metals with nearly localized f-electron degrees of freedom increase the likelihood of these unconventional states. However, access to the quantum limit is typically impeded by the tendency of f-electrons to polarize in a strong magnetic field, consequently weakening the interactions.

View Article and Find Full Text PDF

Chemical bonding in 2D layered materials and van der Waals solids is central to understanding and harnessing their unique electronic, magnetic, optical, thermal, and superconducting properties. Here, we report the discovery of spontaneous, bidirectional, bilayer twisting (twist angle ∼4.5°) in the metallic kagomé MgCoGe at = 100(2) K via X-ray diffraction measurements, enabled by the preparation of single crystals by the Laser Bridgman method.

View Article and Find Full Text PDF

A family of high entropy oxides with the formula MgTaLnO (Ln = La, Pr, Nd, Sm, Eu, Gd) has been discovered and synthesized. Single crystals, 5 mm OD × 2.5 cm, for Ln = Nd have been grown using the laser optical floating zone technique.

View Article and Find Full Text PDF

Background: Adult congenital heart disease (ACHD) is a relatively new subspecialty in the cardiology field. The prevalence of ACHD is estimated at ∼ 3,000 per million adult population. The ACHD patient group is estimated to grow at ∼ 5% per year and in the next decade it is forecast that 1 in 150 young adults will carry some form of ACHD diagnosis.

View Article and Find Full Text PDF

Aims: Improved survival has resulted in increasing numbers and complexity of adults with congenital heart disease (ACHD). International guidelines recommend specialized care but many patients are still not managed at dedicated ACHD centres. This study analysed referral sources and appropriateness of management for patients referred to our tertiary ACHD Centre over the past 3 years.

View Article and Find Full Text PDF

Objective: Survival of patients with repaired tetralogy of Fallot (rToF) into young adulthood is very good. Concerns exist, however, over long-term morbidity and mortality as these subjects reach middle age. We aimed to assess survival and the prevalence of complications in patients with rToF seen in our Adult Congenital Heart Disease (ACHD) service.

View Article and Find Full Text PDF

Background: Congenitally corrected transposition of the great arteries (ccTGA) is a rare congenital heart disease. There have been only few reports of sudden cardiac death (SCD) in patients with ccTGA and reasonable ventricular function.

Methods: A retrospective review of the medical records of all patients attending our adult congenital heart centre, with known ccTGA.

View Article and Find Full Text PDF

Background: Although repair of Tetralogy of Fallot (TOF) and transposition of the great arteries (TGA) has facilitated survival into adulthood, many survivors have residual haemodynamic abnormalities, including exercise intolerance and late right ventricular (RV) failure.

Methods: We studied 40 asymptomatic adult subjects (31.3+/-1.

View Article and Find Full Text PDF

Background: There is concern about whether cardiac damage occurs as a result of prolonged strenuous exercise.

Objective: To investigate whether competing in a triathlon is associated with cardiac damage based on a sustained increase in cardiac troponin T (cTnT), and whether such an increase correlates with echocardiographic changes

Methods: cTnT and echocardiographic measurements were made in 38 participants in the 2001 Australian ironman triathlon. cTnT was measured the day before, immediately after, and the day following the race.

View Article and Find Full Text PDF

The MRI findings of a case of coronary artery fistula occurring in a patient with pulmonary atresia and tricuspid atresia is presented.

View Article and Find Full Text PDF

We report two cases of carotid sinus syndrome secondary to head and neck malignancy. The underlying mechanisms unique to head and neck malignancy and treatments of the syndrome are discussed.

View Article and Find Full Text PDF

Coronary pulmonary fistulae are rare cardiac anomalies. We present the case of a 46-year-old woman with multiple coronary-pulmonary fistulae involving all three coronary arteries. She presented with atypical chest pain and had no obstructive coronary lesion.

View Article and Find Full Text PDF

Objectives: To determine the relationship between age and aortic dilatation in patients with Marfan syndrome and to define the rate of progression of aortic dilatation in these patients.

Design: All patients were evaluated in a multidisciplinary clinic to establish a firm diagnosis of Marfan syndrome. Aortic dimensions were measured by echocardiography and patients with Marfan syndrome were followed up with annual physical and echocardiographic examinations to detect any change in aortic diameter over the subsequent four years.

View Article and Find Full Text PDF

In a previous study, we described a form of nondeletion alpha-thalassemia (alpha T Saudi alpha) found in subjects of Saudi Arabian origin. In the current study, using synthetic oligoprobe hybridization and restriction enzyme analysis, we have demonstrated that the molecular basis of alpha T Saudi alpha is due solely to a single base mutation (AATAAA----AATAAG) in the polyadenylation signal of the alpha 2 gene and that the frameshift mutation in codon 14 of the linked alpha 1 gene is the result of a cloning artefact. The alpha 2 polyadenylation signal mutation occurs in other Middle Eastern and the Mediterranean populations and is responsible for the clinical phenotype of Hb H disease in some Saudi Arabian individuals with five alpha genes (alpha T Saudi alpha/(alpha alpha alpha)T Saudi).

View Article and Find Full Text PDF

Three identical alpha + thalassemia genes, one of which always carried the Hb J Tongariki mutation, have been observed in Vanuatuans. Despite the fact that at least two of them have arisen by different types of crossover event, the expression of all three haplotypes is identical.

View Article and Find Full Text PDF

Each of three families of northern European origin contains a mentally retarded son with hemoglobin H (Hb H) disease. One parent is a carrier of mild alpha-thalassemia and the other is normal, suggesting that this form of Hb H disease results from the interaction between an inherited defect of alpha-chain production and one member of the pair in chromosome 16 and a new mutation on the other. Restriction-enzyme analysis indicated that the new mutation was not the same in the other three patients, and demonstrated at least two hitherto undescribed lesions involving the alpha-globin gene cluster.

View Article and Find Full Text PDF

Restriction endonuclease mapping of nondeletion alpha-thalassemia determinants from a variety of racial groups showed no detectable abnormalities within a 40-kilobase region of the zeta-alpha globin gene cluster. By using a zeta-specific probe, we defined three different types of interactions that give rise to Hb H disease, each involving a nondeletion alpha-thalassemia haplotype. mRNA analysis showed further diversity within these groups, indicating that there are at least three nondeletion determinations.

View Article and Find Full Text PDF

Five Cypriots homozygous for beta +-thalassaemia have inherited deletion or non-deletion forms of alpha-thalassaemia that seem to have modified the usually severe clinical picture to that of mild thalassaemia intermedia. These observations have important implications for the antenatal diagnosis of beta-thalassaemia.

View Article and Find Full Text PDF

We have studied seven Jamaican Negro families in whom the genes for alpha thalassaemia and the sickle cell mutation (betas) were independently segregated. Using a combination of techniques we identified two alpha thalassaemia phenotypes which resemble the severe (alpha thalassaemia 1) and mild (alpha thalassaemia 2) determinants previously described in Orientals. This study has enabled us to clearly correlate the phenotype of alpha thalassaemia with the genotype in this population.

View Article and Find Full Text PDF

We studied 11 families with alpha-thalassemia from the Qatif population of eastern Saudi Arabia to determine the genetic and molecular basis of hemoglobin-H disease, which is being encountered in this area with increasing frequency. The results show that there are two common alpha-thalassemia haplotypes, a deletion (-alpha/) determinant and a nondeletion (alpha alpha T/) determinant, which interact to produce a series of overlapping phenotypes. The most severe, hemoglobin-H disease, results from the homozygous state for the nondeletion determinant--a pattern of inheritance not previously recognized for this condition.

View Article and Find Full Text PDF