Magneto-chemical studies with a new ultrasensitive superconducting quantum magnetometer

A magnetometer utilizing quantum superconductivity as the basis for the flux sensor element has been designed and used for biochemical susceptibility measurements in the temperature range from 1.5°K to 300°K. The sensitivity and reproducibility of this instrument have been tested by measurements on small amounts of material of well-known susceptibilities. Using this instrument the temperature dependence of the magnetic susceptibilities of oxy- and metaquohemerythrin have been measured and for the first time their anti-ferromagnetic components have been unambigiously resolved. From this data the exchange coupling constants between the two high-spin iron (III) atoms in each subunit have been determined to be -77 and -134 cm^(-1) respectively

Anomalous Periodicity of the Current-Phase Relationship of Grain-Boundary Josephson Junctions in High-Tc Superconductors

The current-phase relation (CPR) for asymmetric 45 degree Josephson junctions between two d-wave superconductors has been predicted to exhibit an anomalous periodicity. We have used the single-junction interferometer to investigate the CPR for this kind of junctions in YBCO thin films. Half-fluxon periodicity has been experimentally found, providing a novel source of evidence for the d-wave symmetry of the pairing state of the cuprates.Comment: 4 pages, 5 figure

Studying Cat (Felis catus) Diabetes: Beware of the Acromegalic Imposter

Naturally occurring diabetes mellitus (DM) is common in domestic cats (Felis catus). It has been proposed as a model for human Type 2 DM given many shared features. Small case studies demonstrate feline DM also occurs as a result of insulin resistance due to a somatotrophinoma. The current study estimates the prevalence of hypersomatotropism or acromegaly in the largest cohort of diabetic cats to date, evaluates clinical presentation and ease of recognition. Diabetic cats were screened for hypersomatotropism using serum total insulin-like growth factor-1 (IGF-1; radioimmunoassay), followed by further evaluation of a subset of cases with suggestive IGF-1 (>1000 ng/ml) through pituitary imaging and/ or histopathology. Clinicians indicated pre-test suspicion for hypersomatotropism. In total 1221 diabetic cats were screened; 319 (26.1%) demonstrated a serum IGF-1>1000 ng/ml (95% confidence interval: 23.6-28.6%). Of these cats a subset of 63 (20%) underwent pituitary imaging and 56/63 (89%) had a pituitary tumour on computed tomography; an additional three on magnetic resonance imaging and one on necropsy. These data suggest a positive predictive value of serum IGF-1 for hypersomatotropism of 95% (95% confidence interval: 90-100%), thus suggesting the overall hypersomatotropism prevalence among UK diabetic cats to be 24.8% (95% confidence interval: 21.2-28.6%). Only 24% of clinicians indicated a strong pre-test suspicion; most hypersomatotropism cats did not display typical phenotypical acromegaly signs. The current data suggest hypersomatotropism screening should be considered when studying diabetic cats and opportunities exist for comparative acromegaly research, especially in light of the many detected communalities with the human disease

Low-frequency measurement of the tunneling amplitude in a flux qubit

We have observed signatures of resonant tunneling in an Al three-junction qubit, inductively coupled to a Nb LC tank circuit. The resonant properties of the tank oscillator are sensitive to the effective susceptibility (or inductance) of the qubit, which changes drastically as its flux states pass through degeneracy. The tunneling amplitude is estimated from the data. We find good agreement with the theoretical predictions in the regime of their validity.Comment: REVTeX4, 3pp., 3 EPS figures. v2: new sample, textual clarifications. v3: minor polishing; final, to appear in PRB Rapid

Single session endoscopic management of intrinsic ureteropelvic junction obstruction and concomitant renal stone disease in a child: a case report

BACKGROUND: Percutaneous nephrolithotomy is a well known therapeutic modality for stone diseases of childhood. Antegrade and retrograde endopyelotomies are also well defined options of treatment for secondary ureteropelvic junction obstruction. Yet there are few reports regarding endoscopic therapy of intrinsic ureteropelvic junction obstruction. To our knowledge, there exist only a few reports of endosurgical treatment of children with stone disease and with concomitant intrinsic ureteropelvic junction obstruction, in the literature. CASE PRESENTATION: We present the endoscopic management of stone disease and concomitant intrinsic ureteropelvic junction obstruction of a child in one session. CONCLUSION: Percutaneous nephrolithotomy and antegrade endopyelotomy is combined safely with successful outcome in a child