Remotely-sensed atomic magnetometry

Thesis (M.S.)--Boston UniversityCoherent population trapping (CPT) effects can be realized with frequency mod- ulated lasers and compact vapor cells of alkali metals such as Rubidium-87. Using these optical resonances, one can readily measure the hyperfine separation of this three-level atom. In the presence of a magnetic field, the Zeeman effect causes magnetic sublevels of these hyperfine ground states to split; the frequency of such splitting can be measured in an ensemble of Rubidium atoms with the magnetometer we have constructed. While other groups have constructed magnetometers based on these effects, none to our knowledge have investigated the capability to measure magnetic fields remotely. Most atomic-optical magnetometers,colocate the transmit and receive optical system with the vapor cell itself or require fiber optics at the location of the cell; our free-space technique with a reflective geometry lends itself to measurement at distances greater than could be achieved with those methods. We have developed a laboratory FM laser spectrometer that interrogates CPT resonances to measure magnetic fields with the vapor cell not necessarily co-located with the spectrometer. Its intrinsic linewidth (in the presence of transit-time broadening) is less than 30 kilohertz, which allows measurements on the order of 2 microtesla. We present results concerning the accuracy of the magnetometer at about one meter of standoff distance, and describe considerations for measurements at longer distances

Unusual presentation of thyrotoxicosis as complete heart block and renal failure: a case report

<p>Abstract</p> <p>Introduction</p> <p>Thyrotoxicosis is a clinical entity often very difficult to diagnose without biochemical confirmation as its clinical features can be highly varied. The most common cardiac manifestations of thyrotoxicosis are resting sinus tachycardia, supraventricular tachycardia including atrial fibrillation and atrial flutter with or without cardiac failure. Bradycardia and atrio-ventricular conduction defects are very uncommon in thyrotoxicosis.</p> <p>Case presentation</p> <p>We report the case of a 59-year-old Caucasian man presenting with progressive weight loss, abnormal liver function, acute renal failure and complete heart block due to thyrotoxicosis.</p> <p>Conclusion</p> <p>Thyrotoxicosis should be considered as a possible diagnosis in patients with bradycardia and heart blocks associated with abnormal symptoms like weight loss. Nevertheless, the clinical, electrophysiological and biochemical abnormalities associated with thyrotoxicosis may be completely reversible restoring euthyroid state.</p