Towards Neutron Capture on Exotic Nuclei: Demonstrating (d,pγ) as a Surrogate Reaction for (n,γ).

The neutron-capture reaction plays a critical role in the synthesis of the elements in stars and is important for societal applications including nuclear power generation and stockpile-stewardship science. However, it is difficult-if not impossible-to directly measure neutron capture cross sections for the exotic, short-lived nuclei that participate in these processes. In this Letter we demonstrate a new technique which can be used to indirectly determine neutron-capture cross sections for exotic systems. This technique makes use of the (d,p) transfer reaction, which has long been used as a tool to study the structure of nuclei. Recent advances in reaction theory, together with data collected using this reaction, enable the determination of neutron-capture cross sections for short-lived nuclei. A benchmark study of the ^{95}Mo(d,p) reaction is presented, which illustrates the approach and provides guidance for future applications of the method with short-lived isotopes produced at rare isotope accelerators.

Constraining Neutron Capture Cross Sections for Unstable Nuclei with Surrogate Reaction Data and Theory.

Obtaining reliable data for nuclear reactions on unstable isotopes remains an extremely important task and a formidable challenge. Neutron capture cross sections-crucial ingredients for models of astrophysical processes, national security applications, and simulations of nuclear energy generation-are particularly elusive, as both projectile and target in the reaction are unstable. We demonstrate a new method for determining cross sections for neutron capture on unstable isotopes, using ^{87}Y(n,γ) as a prototype. To validate the method, a benchmark experiment is carried out to obtain the known ^{90}Zr(n,γ) cross section analogously. Our approach, which employs an indirect ("surrogate") measurement combined with theory, can be generalized to a larger class of nuclear reactions. It can be used both with traditional stable-beam experiments and in inverse kinematics at rare-isotope facilities.

Quadrupole collectivity in neutron-rich Fe and Cr isotopes.

Intermediate-energy Coulomb excitation measurements are performed on the N ≥ 40 neutron-rich nuclei (66,68)Fe and (64)Cr. The reduced transition matrix elements providing a direct measure of the quadrupole collectivity B(E2;2(1)(+) → 0(1)(+)) are determined for the first time in (68)Fe(42) and (64)Cr(40) and confirm a previous recoil distance method lifetime measurement in (66)Fe(40). The results are compared to state-of-the-art large-scale shell-model calculations within the full fpgd neutron orbital model space using the Lenzi-Nowacki-Poves-Sieja effective interaction and confirm the results of the calculations that show these nuclei are well deformed.

MDA-MDMA concentrations in urine specimens.

Urine specimens collected from active-duty U.S. Army personnel were submitted for analysis to the Tripler Army Medical Center, Forensic Toxicology Drug Testing Laboratory as part of the random drug testing program. During an 18-month drug-screening period, 34 specimens tested positive for amphetamines with the Roche Abuscreen Radioimmunoassay for Methamphetamine (High Specificity); based on gas chromatographic-mass spectrometric (GC-MS) analysis, the presence of 3,4-methylenedioxymethamphetamine (MDMA) was suspected. These samples were subsequently submitted to the Division of Forensic Toxicology, Office of the Armed Forces Medical Examiner, Armed Forces Institute of Pathology for further testing. All 34 samples screened positive using both the Abbott TDx Amphetamine/ Methamphetamine II assay and the Amphetamine class assay. Confirmation and quantitation by GC-MS revealed the presence of both MDMA and 3,4-methylenedioxyamphetamine (MDA) in all samples. The MDMA concentrations ranged from 0.38 to 96.2 mg/L (mean, 13.4 mg/L) and the MDA concentrations ranged from 0.15 to 8.6 mg/L (mean, 1.6 mg/L). The mean ratio of MDA, the N-demethylation metabolite of MDMA, to MDMA was 0.15, similar to the ratio of amphetamine, the N-demethylation metabolite of methamphetamine, to methamphetamine of 0.10. The presence of MDA in urine specimens at a concentration approximately 10-15% that of the MDMA present is consistent with MDMA metabolism, which may be indicative of the use of MDMA only, as compared with the combined use of both drugs.

Forensic drug testing for opiates. VI. Urine testing for hydromorphone, hydrocodone, oxymorphone, and oxycodone with commercial opiate immunoassays and gas chromatography-mass spectrometry.

Opiate testing for morphine and codeine is performed routinely in forensic urine drug-testing laboratories in an effort to identify illicit opiate abusers. In addition to heroin, the 6-keto-opioids, including hydromorphone, hydrocodone, oxymorphone, and oxycodone, have high abuse liability and are self-administered by opiate abusers, but only limited information is available on detection of these compounds by current immunoassay and gas chromatographic-mass spectrometric (GC-MS) methods. In this study, single doses of hydromorphone, hydrocodone, oxymorphone, and oxycodone were administered to human subjects, and urine samples were collected before and periodically after dosing. Opiate levels were determined in a quantitative mode with four commercial immunoassays, TDx opiates (TDx), Abuscreen radioimmunoassay (ABUS), Coat-A-Count morphine in urine (CAC), and EMIT d.a.u. opiate assay (EMIT), and by GC-MS. GC-MS assay results indicated that hydromorphone, hydrocodone, oxymorphone, and oxycodone administration resulted in rapid excretion of parent drug and O-demethylated metabolites in urine. Peak concentrations occurred within 8 h after drug administration and declined below 300 ng/mL within 24-48 h. Immunoassay testing indicated that hydromorphone, hydrocodone, and oxycodone, but not oxymorphone, were detectable in urine by TDx and EMIT (300-ng/mL cutoff) for 6-24 h. ABUS detected only hydrocodone, and CAC failed to detect any of the four 6-keto-opioid analgesics. Generally, immunoassays for opiates in urine displayed substantially lower sensitivities for 6-keto-opioids compared with GC-MS. Consequently, urine samples containing low to moderate concentrations of hydromorphone, hydrocodone, oxymorphone, and oxycodone will likely go undetected when tested by conventional immunoassays.

Detection of amphetamine and methamphetamine in urine by gas chromatography/mass spectrometry following derivatization with (-)-menthyl chloroformate.

A gas chromatography/mass spectrometry assay was developed for the detection of amphetamine and methamphetamine in urine. These drugs were detected as carbamate derivatives following reaction with (-)-menthyl chloroformate. Selected ion monitoring of the 226, 182, and 227 dalton ions for amphetamine and the 240, 102, and 196 dalton ions for methamphetamine provided positive analyte identification. Quantitative values obtained by isotope dilution mass spectrometry displayed a linear response from below 50 to above 6,000 ng/mL. Differentiation of over-the-counter (R)-methamphetamine from illicit (S)-methamphetamine was accomplished by chromatographic separation of the diastereomeric derivatives on an achiral column. No interferences were observed from ephedrine, pseudoephedrine, phentermine, phenylpropanolamine, or 2-phenylethylamine.

Acute pancreatitis and vitamin K deficiency in pregnancy.

Two patients with acute pancreatitis in pregnancy are described. In both, bleeding from vitamin K deficiency occurred after the initial attack of pancreatitis and the bleeding tendency was successfully treated with vitamin K.

Reduced carbohydrate intake in the preparatory diet and the reliability of the oral glucose tolerance test.

Two USAF flying populatins of 622 subjects each were subjected to the oral glucose tolerance test. One of these populations was prepared for the test by the ingestion of at least 300 grams per day (g/d) of dietary carbohydrate for the 3 d preceding the test; the other by 150 g/d of dietary carbohydrate. Statistical analysis of the data obtained from these populations revealed no change in the reliability of the oral glucose tolerance test as a diagnostic tool. Thaf school of Aerospace Medicine Consultation Service on all patients undergoing oral glucose tolerance tests.

Exercise-induced asthma.

Tests in three patients with asthma occurring only on exertion showed that F.E.V.(1) fell progressively on exercise, to reach a minimum after 10 minutes. All patients showed a striking metabolic acidosis, with an accumulation of the products of anaerobic metabolism.