Coupled optical microcavities: an enhanced refractometric sensing configuration.

We theoretically investigate the application of coupled optical microcavities as refractive index sensors. Coupled microcavities support a very sharp asymmetrical Fano resonance, which gives rise to faster changes in output transmission than the changes from a single cavity. With the output transmission at a fixed wavelength that varies much faster than it does in a single-cavity resonance, the result is enhanced sensitivity of the device to the changes in refractive index. In addition, it is observed that both thermal and optical Kerr effects can be utilized to improve the sensitivity.

Quantum nondemolition measurement of photon number via optical Kerr effect in an ultra-high-Q microtoroid cavity.

We theoretically investigate a quantum nondemolition (QND) measurement with optical Kerr effect in an ultra-high-Q microtoroidal system. The analytical and numerical results predict that the present QND measurement scheme possesses a high sensitivity, which allows for detecting few photons or even single photons. Ultra-high-Q toroidal microcavity may provide a novel experimental platform to study quantum physics with nonlinear optics at low light levels.

Trends in the care of patients with acute myocardial infarction at a university-affiliated Veterans Affairs Medical Center.

BACKGROUND: Acute cardiac care of the veterans at Veterans Administration (VA) hospitals has been thought of as poor in quality. We examined the use of life-saving, evidence-based medical therapy in patients admitted with acute myocardial infarction to the University of Arkansas for Medical Sciences-affiliated VA Medical Center in Little Rock and compared the use of this therapy with other hospitals in Arkansas and in the rest of the nation. METHODS: Use of life-saving medical therapy in 117 patients admitted with acute myocardial infarction from January 2002 to December 2002 was compared with the National Registry of Myocardial Infarction database for the identical period. RESULTS: Heparin/low-molecular-weight heparin and glycoprotein IIb/IIIa inhibitors were used in 88% and 66% of patients, respectively. Aspirin, beta adrenergic-blocking agents, angiotensin-converting enzyme (ACE) inhibitors/angiotensin receptor blockers (ARBs), and 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) were used in 92%, 93%, 62%, and 79% of the patients, respectively. The use of these therapies was better than in similar patients in Arkansas (P < .001) and the United States as a whole (P < .01). Calcium-channel blockers were used in 16% of the patients. At a mean follow-up period of 1.5 years, use of beta blockers and aspirin had decreased, whereas the use of statins and ACE inhibitors/ARBs was unchanged. CONCLUSION: This study shows that patients with acute myocardial infarction admitted to this university-affiliated VA Medical Center receive evidence-based life-saving medical therapy more often than in the rest Arkansas or in the entire United States. More important, patients at this federal institution continue to receive life-saving medical therapy during follow-up. Better use of evidence-based therapy may be related to affiliation of this VA Medical Center with a teaching institution where board certified cardiologists are involved in short- and long-term care of these patients.

Bradycardia during therapy for multiple myeloma with thalidomide.

We studied the medical records of 96 patients who received thalidomide and 104 patients who made up a control group. We found that 53% of patients (52 patients) using thalidomide had a heart rate of <60 beats/min at some point during follow-up and 19% of thalidomide patients (10 patients) developed symptom-related bradycardia. Reducing the thalidomide dose appeared to alleviate symptoms in most patients.