3He spin-dependent cross sections and sum rules.

We present a measurement of the spin-dependent cross sections for the 3He over -->(e over -->,e')X reaction in the quasielastic and resonance regions at a four-momentum transfer 0.1< or =Q2< or =0.9 GeV2. The spin-structure functions have been extracted and used to evaluate the nuclear Burkhardt-Cottingham and extended Gerasimov-Drell-Hearn sum rules for the first time. The data are also compared to an impulse approximation calculation and an exact three-body Faddeev calculation in the quasielastic region.

Fatal seizures after flumazenil administration in a patient with mixed overdose.

OBJECTIVE: To report a fatal case of refractory status epilepticus precipitated by flumazenil use in a mixed benzodiazepine-tricyclic antidepressant overdose. CASE SUMMARY: A 39-year-old woman was brought to the emergency room (ER) in a stupor from a suspected suicidal overdose of an unknown mixture of drugs. Past medical history included seizures and psychiatric disorders managed with benzodiazepine and tricyclic antidepressants. Initial ER electrocardiogram showed a QRS interval of 136 milliseconds. The patient developed refractory seizures after being given flumazenil. Lorazepam, phenytoin, and phenobarbital were administered; however, seizures persisted for 4 hours, resulting in rhabdomyolysis, acute renal failure, severe brain damage, and death. DISCUSSION: Flumazenil should be used with caution in patients with chronic benzodiazepine use, prior seizure history, or when a mixed overdose is suspected. Flumazenil may unmask tricyclic antidepressant-induced seizures by antagonizing the antiepileptic effect of concomitantly ingested benzodiazepine. In this patient seizures occurred within two minutes of flumazenil administration. As benzodiazepine-induced central nervous system depression is rarely life-threatening, the use of flumazenil must be balanced against potential risk. CONCLUSIONS: Seizure risk factors should be assessed in all patients in whom flumazenil use is considered. If risk factors are present, the benefit of flumazenil use is outweighed by the potential risk. If flumazenil is used, resulting seizures may require larger doses of benzodiazepine.

Measurement of the generalized forward spin polarizabilities of the neutron.

The generalized forward spin polarizabilities gamma(0) and delta(LT) of the neutron have been extracted for the first time in a Q2 range from 0.1 to 0.9 GeV2. Since gamma(0) is sensitive to nucleon resonances and delta(LT) is insensitive to the Delta resonance, it is expected that the pair of forward spin polarizabilities should provide benchmark tests of the current understanding of the chiral dynamics of QCD. The new results on delta(LT) show significant disagreement with chiral perturbation theory calculations, while the data for gamma(0) at low Q2 are in good agreement with a next-to-leading-order relativistic baryon chiral perturbation theory calculation. The data show good agreement with the phenomenological MAID model.

Q2 evolution of the neutron spin structure moments using a 3He target.

We have measured the spin structure functions g(1) and g(2) of 3He in a double-spin experiment by inclusively scattering polarized electrons at energies ranging from 0.862 to 5.058 GeV off a polarized 3He target at a 15.5 degrees scattering angle. Excitation energies covered the resonance and the onset of the deep inelastic regions. We have determined for the first time the Q2 evolution of Gamma(1)(Q2)= integral (1)(0)g(1)(x,Q2)dx, Gamma(2)(Q2)= integral (1)(0)g(2)(x,Q2)dx, and d(2)(Q2)= integral (1)(0)x(2)[2g(1)(x,Q2)+3g(2)(x,Q2)]dx for the neutron in the range 0.1< or =Q2< or =0.9 GeV2 with good precision. Gamma(1)(Q2) displays a smooth variation from high to low Q2. The Burkhardt-Cottingham sum rule holds within uncertainties and d(2) is nonzero over the measured range.

Q2 evolution of the generalized Gerasimov-Drell-Hearn integral for the neutron using a 3He target.

We present data on the inclusive scattering of polarized electrons from a polarized 3He target at energies from 0.862 to 5.06 GeV, obtained at a scattering angle of 15.5 degrees. Our data include measurements from the quasielastic peak, through the nucleon resonance region, and beyond, and were used to determine the virtual photon cross-section difference sigma(1/2)-sigma(3/2). We extract the extended Gerasimov-Drell-Hearn integral for the neutron in the range of four-momentum transfer squared Q2 of 0.1-0.9 GeV2.