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Biomedical subjects

E G Cohen

Publications and source records attributed to E G Cohen.

5 recordsLinked to original sources
PubMed2001

Collapse in systems with attractive nonintegrable potentials.

Collapse, or a gravitational-like phase transition, is found in microcanonical ensembles of particles with an attractive 1/r(alpha) potential not only for alpha = 1 but for all 0<alpha<3. The phase behavior of the system is complex: If an effective sufficiently short-range cutoff is applied, the density of the collapsed phase is finite everywhere; if not, the collapse results in a density singularity. Also, with increasing effective cutoff range, the gravitational phase transition will cross over to a normal first-order phase transition.

Journal Article↗
PubMed2001

Phase transitions in systems with 1/r(alpha) attractive interactions.

Collapse, or a gravitational-like phase transition is studied in a microcanonical ensemble of particles with an attractive 1/r(alpha) potential. A mean-field continuous integral equation is used to determine a saddle-point density profile that extremizes the entropy functional. For all 0 < alpha < 3, a critical energy is determined below which the entropy of the system exhibits a discontinuous jump. If an effective short-range cutoff is applied, the entropy jump is finite; if not, the entropy diverges to +infinity. A stable integral equation solution represents a state with maximal entropy; the reverse is always true only for a modified integral equation introduced here.

Journal Article↗
PubMed2001

Changing trends in angioedema.

Angioedema can be a life-threatening event presenting to otolaryngologists, emergency medicine physicians, and other physicians. Recent reports suggest an increasing role of angiotensin-converting enzyme inhibitors (ACEIs) in the causation of angioedema. Sixty-four cases occurring between 1994 and 1998 were identified and examined retrospectively. Fifty-eight percent of patients presenting with angioedema were using ACEIs. Ninety-four percent of patients overall, and 92% of patients with ACEI-associated angioedema, were African-American. Tongue, lip, facial, and supraglottic edema were most common. Treatment included intubation in 13% and intensive care unit monitoring in 20%. Nearly all patients were treated with corticosteroids and antihistamines. There were no deaths. Angioedema associated with ACEI use appears to be much more common than previously reported. African-American patients may be at higher risk for angioedema with ACEI use. Successful management was achieved with observation, expectant airway management, corticosteroids, and discontinuation of ACEIs. Patients without airway obstruction or pharyngeal or laryngeal edema who improved with treatment and observation were successfully treated as outpatients.

Adult↗