The 40Ar(d,p)41Ar cross section between 3-7 MeV.

To determine the safety of using argon as a deuteron beam stopping material, the  40Ar(d,p)41Ar cross section was measured at average deuteron energies of 3.6 MeV, 5.5 MeV, and 7.0 MeV using an activation method. A 16-MeV deuteron beam produced by Lawrence Berkeley National Laboratory's 88-Inch Cyclotron was degraded to each energy by nickel foils and the front wall of an aluminum gas chamber. The reduced-energy deuterons were used to activate a sample of natAr gas. After each irradiation, the gas chamber's  41Ar activation was measured with a high-purity germanium detector. The cross sections measured were larger than a previous measurement by ∼40%.

Precision measurement of relative γ-ray intensities from the decay of 61Cu.

A discrepancy, well outside reported uncertainties, has been observed between the accepted and measured values of the intensity ratio of the two strongest γ rays following 61Cu ß+ decay. This discrepancy has significant impact since the natNi(d,x)61Cu reaction has historically been one of only a few IAEA recommendations for use as a deuteron flux monitor and a considerable number of published cross sections measured in ratio to that beam monitor cross section may depend on the choice of either the first or second strongest γ ray in those calculations. To determine the magnitude of this error most precisely, over a hundred separate measurements of the 283 keV to 656 keV γ-ray emission ratio were collected from seven experiments and a variety of detectors and detection geometries. A weighted average of all these measurements indicates an error in the value listed in the Nuclear Data Sheets of 11% in either the primary or second-highest intensity γ ray of 61Cu, potentially introducing an 11% error in 61Cu production cross section measurements, cross sections using nickel activation as a deuteron beam current monitor, or in dose rates when 61Cu is used in nuclear medicine. General agreement with the Data Sheets with ten other intensity ratios suggests the most probable error is in the secondary (656 keV) emission, which accordingly should be updated from 10.8% to 9.69%.

Design and initial results from a kilojoule level Dense Plasma Focus with hollow anode and cylindrically symmetric gas puff.

We have designed and built a Dense Plasma Focus (DPF) Z-pinch device using a kJ-level capacitor bank and a hollow anode, and fueled by a cylindrically symmetric gas puff. Using this device, we have measured peak deuteron beam energies of up to 400 keV at 0.8 kJ capacitor bank energy and pinch lengths of ∼6 mm, indicating accelerating fields greater than 50 MV/m. Neutron yields of on the order of 10(7) per shot were measured during deuterium operation. The cylindrical gas puff system permitted simultaneous operation of DPF with a radiofrequency quadrupole accelerator for beam-into-plasma experiments. This paper describes the machine design, the diagnostic systems, and our first results.

Neutron production from feedback controlled thermal cycling of a pyroelectric crystal.

The LLNL Crystal Driven Neutron Source is operational and has produced record ion currents of approximately 10 nA and neutron output of 1.9(+/-0.3)x10(5) per thermal cycle using a crystal heating rate of 0.2 degrees C/s from 10 to 110 degrees C. A 3 cm diameter by 1 cm thick LiTaO(3) crystal with a socket secured field emitter tip is thermally cycled with feedback control for ionization and acceleration of deuterons onto a deuterated target to produce D-D fusion neutrons. The entire crystal and temperature system is mounted on a bellows which allows movement of the crystal along the beam axis and is completely contained on a single small vacuum flange. The modular crystal assembly permitted experimental flexibility. Operationally, flashover breakdowns along the side of the crystal and poor emitter tip characteristics can limit the neutron source. The experimental neutron results extend earlier published work by increasing the ion current and pulse length significantly to achieve a factor-of-two higher neutron output per thermal cycle. These findings are reviewed along with details of the instrument.

Cervical sympathetic chain schwannomas masquerading as carotid body tumors.

Cervical sympathetic chain (CSC) schwannoma is a rare neurogenic tumor that can mimic a carotid body tumor (CBT). Two male patients aged 33 and 49 years old were referred for a cervical mass thought to be a CBT. Both patients were found to have an asymptomatic, pulsatile, nontender mass located at the level of the angle of the mandible. Both patients were neurologically asymptomatic and cranial nerves were normal. Both patients underwent neck exploration and resection of the mass involving the CSC. Postoperatively, a Horner's syndrome was present. Histopathology confirmed both tumors to be schwannomas of the CSC. At follow-up, both patients are asymptomatic with no recurrence. The main imaging criterion to differentiate a CBT from a CSC schwannoma is the lack of hypervascularity of the latter. Malignant transformation is extremely rare. Tumor excision gives excellent results with no local recurrence. Horner's syndrome is an expected postoperative complication.

Bile duct stricture in an infant with gastroschisis treated by percutaneous transhepatic drainage, biliary stenting, and balloon dilation.

A newborn twin with an antenatal diagnosis of gastroschisis underwent staged repair of the abdominal wall defect. She developed multiple fistulae due to ischemic bowel and then abdominal wall dehiscence requiring additional surgical interventions. Obstructive jaundice, first evident at 3 weeks of age, became progressively severe. A stricture of the common bile duct was diagnosed by percutaneous transhepatic cholangiography. The stricture was treated by percutaneous biliary drainage, biliary stenting, and balloon dilation of the common bile duct. These procedures, commonly used in adults for biliary decompression, may be useful alternatives to surgical intervention in infants and children with obstructive jaundice due to bile duct stricture.

Repair of a false aneurysm of the aortic arch.

A 66-year-old man having previously undergone repair of aneurysms of the ascending, transverse and infrarenal aorta, presented with a large false aneurysm of the aortic arch. Successful repair of the aneurysm was achieved under a state of profound hypothermia and circulatory arrest. The patient remains well and free from aortic aneurysmal disease two years after surgery.

Nephrostolithotomy: percutaneous techniques for urinary calculus removal.

Recently the technique of percutaneous nephrostomy has been modified to allow the percutaneous extraction of urinary calculi. This communication describes experience with the percutaneous extraction of 63 calculi from the urinary tract. An overall success rate of 87%, a low incidence of complications (about 3%), a fast recovery, and sooner return to work are obtained. Several technical variants including grasping, fragmentation, flushing, and removal under direct vision have been used. In most cases, a combination of the different techniques has to be used in one patient. Essential to the technique is the introduction of large dilators into the kidney.

Removal of partially extruded steel coils.

The authors use a snare for the antegrade extraction of coils which have become partially extruded during therapeutic embolization.

Ivalon shavings: technical considerations of a new embolic agent.

Ivalon (polyvinyl alcohol sponge) shavings can be used as a permanent embolic material. When injected as a suspension with assorted particles of proper size, congenital arteriovenous malformations can be cured, eliminating the need for surgical excision.

Transluminal dilatation of coarctation of the abdominal aorta. An experimental study in dogs.

The optimal treatment for recurrent coarctation of the aorta remains undefined. Recurrent stenosis following surgical repair occurs in 6-48% of cases involving the thoracic aorta. Because of the high morbidity and mortality associated with surgery, an alternate approach such as transluminal angioplasty is desirable. To evaluate this possibility, the authors created several experimental lesions to test their capability for dilatation, using the percutaneous transluminal technique. The results indicate that balloon dilatation of coarctation after end-to-end anastomosis is difficult or impossible. Dilatation of other types of suture lines may also be difficult due to the large amount of fibrous tissue at the anastomotic site, which is not amenable to balloon dilatation. Thus surgery remains the preferred form of therapy.

Embolization of the spermatic vein for treatment of infertility: a new approach.

A new transjugular technique for spermatic venography and nonsurgical transcatheter occlusion of incompetent spermatic veins is described. With this technique, the left spermatic vein was easily catheterized in 28 of 30 patients examined, and in 21 patients the vein could be occluded. Right spermatic vein catheterization was attempted in 25 patients. Right-sided spermatic vein occlusion was successful in 17 of 24 patients. The vein could not be selectively entered only twice. Bilateral incompetence of the spermatic veins in men with primary sterility is the rule rather than the exception. Valvular incompetence does not necessarily produce a clinically detectable varicocele. Bilateral venography is indicated in all men with abnormal spermiograms.

[Distribution of pathogenic enterobacteria in the water of open reservoirs]. / Rasprostranenie patogennykh énterobakterii v vode otkrytykh vodoemov.

Investigations carried out indicated that the main source of microbial contamination of open reservoirs were effluents often drained without any purification and disinfection. Salmonellae were isolated in 10.6 +/- 0.88% of the water samples examined in the Southern regions of the country. Isolation of pathogenic enterobacteria from the water of open reservoirs was seasonal, with the maximal percentage in winter and in spring, this being connected with delay of self-purification processes in the cold seasons of the year. Serovars isolated from water and patients proved to be identical. There was no direct correlation between the coli index and the isolation of pathogenic enterobacteria.