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Pelvic fractures and sacroiliac joint (SI) diastasis are debilitating injuries which can drastically decrease an individual's functional capacity, and lead to significant morbidity and mortality. In younger, healthier populations, pelvic fractures are usually the result of sudden traumatic forces, such as a motor vehicle collision. Atraumatic pelvic fractures can also occur, and are most commonly due to age related changes and osteoporosis. Even with prompt surgical management, pelvic fractures often result in a host of challenging complications such as disruption of the SI joint with subsequent limitations in mobility and chronic pain. In this case report, we present a novel treatment of SI diastasis, secondary to corticosteroid induced osteoporosis and pelvic fractures. We performed percutaneous bilateral poly-methyl-methacrylate (PMMA) SI joint fusions under CT-guidance. Here we describe a case of bilateral SI joint CT guided percutaneous arthroplasty for osteoporotic SI joint diastasis and pelvic fractures, resulting in a rapid resolution of SI joint pain and restoration of the ability to ambulate in a previously wheelchair-bound patient. This may be of particular benefit in patients who are poor surgical candidates who experience osteoporotic fractures and would be otherwise unable to receive definitive operative management of their pathologic fractures.

Aortic injury is a frequently encountered condition that can present as a life-threatening emergency. When this injury occurs in the retroperitoneal portion of the aorta, it can be difficult to diagnose and treat because of the location. Although surgical repair remains the mainstay of treatment, surgery might not be an option for some patients. We have presented a case of a 54-year-old nonoperative candidate who had experienced iatrogenic retroperitoneal abdominal aortic rupture with pseudoaneurysm formation. The patient was successfully treated with the novel use of a proven technique: direct percutaneous embolization of the pseudoaneurysm sac via a translumbar approach under image guidance.

Most patients have a time limited indication for inferior vena cava filtration. When the indication has expired, a retrievable inferior vena cava filter should be removed percutaneously, unless the risks of retrieval outweigh the benefits. Over time, long term indwelling inferior vena cava filters may experience complications, such as strut penetration, migration, thrombosis, tilt, fracture, and inferior vena cava stenosis. Long term indwelling retrievable inferior vena cava filters may become embedded in the wall of the inferior vena cava, making percutaneous retrieval difficult. However, this is not always the case, and they also may be easily and safely removed using simple techniques. We present a case of a long term indwelling retrievable inferior vena cava filter that was easily removed using simple techniques, 16.5 years after placement.

OBJECTIVE. The purpose of this article was to evaluate the feasibility and efficacy of percutaneous fluoroscopic-guided stone retrieval from the cystic duct and antegrade common bile duct (CBD) stone advancement into the duodenum exclusively through a cholecystostomy tube. MATERIALS AND METHODS. Twenty-one patients with acute cholecystitis and choledocholithiasis or an impacted cystic duct stone who underwent percutaneous cholecystostomy tube placement were retrospectively enrolled in this study. The patients had a contra-indication for cholecystectomy (17 patients because of comorbidities and one who declined surgery) or had failed endoscopic retrograde stone removal attempts (three patients). RESULTS. The 21 patients underwent subsequent percutaneous CBD (17 patients) and cystic duct (nine patients) stone removal on follow-up sessions through the percutaneous cholecystostomy track using moderate sedation. A total of 32 stone removal procedures were performed. Seventeen patients underwent balloon dilatation sphincterotomy, after which the CBD stones were pushed forward into the duodenum using a compliant balloon. Seven patients also had stone removal from the cystic duct by a stone retrieval basket. The primary technical success rate for removal of all CBD and cystic duct stones was 76%. The secondary technical success rate was 100%. The clinical success rate was 74%. All patients tolerated the procedures well without major complication. The clinical follow-up interval ranged from 2 to 2310 days (median, 30 days), with no incidence of postprocedural complications. CONCLUSION. Percutaneous transcholecystic common bile and cystic duct stone removal through an existing cholecystostomy access is a safe and effective procedure that is well tolerated.

This paper provides a review of research performed at two novel, large-scale ion implantation and deposition facilities developed within the High Energy-Density Physics Group at Los Alamos National Laboratory: the Plasma Source Ion Implantation (PSII) facility, where large-area (several m2) workpieces are being implanted with nitrogen and carbon for tribological applications using a 100 kV, 60 A pulse modulator, and the High Intensity Pulsed Ion Beam (HIPIB) facility, where high-temperature superconductor and diamond-like carbon films are being deposited from substrate material evaporated with a 300 keV, 30 kA ion beam capable of energy fluences of 30 kJ/cm2 per pulse over an area of 25 cm2.

Diamondlike carbon (DLC) films were prepared by high‐intensity pulsed‐ion‐beam ablation of graphite targets. A 350 keV, 35 kA, 400 ns beam, consisting primarily of hydrogen, carbon, and oxygen ions was focused onto a graphite target at a fluence of 15–45 J/cm2. Amorphous carbon films were deposited at up to 30 nm per pulse, corresponding to an instantaneous deposition rate greater than 1 mm/s. Electrical resistivities were between 1 and 1000 Ω cm. Raman spectra indicate that diamondlike carbon is present in most of the films. Electron‐energy‐loss spectroscopy indicates significant amounts of sp3‐bonded carbon, consistent with the presence of DLC. Scanning electron microscopy showed most films contain 100 nm features, but micron size particles were deposited as well. Initial tests revealed favorable electron field‐emission behavior.

An aluminum (Al) target was laser ablated in a nitrogen (N2) atmosphere, producing aluminum nitride (AlN) powder. These powders were calcined at 900°C for 2 h. Powders were produced at various nitrogen pressures, and the calcined powders were tested for unreacted aluminum content, using differential thermal analysis (DTA). The AlN powder, produced at a laser fluence of 12 J/cm2 and a nitrogen pressure of 10.0 kPa (75 torr), showed no evidence of unreacted aluminum by DTA and was phase-pure AlN by X-ray diffraction (XRD). The surface area of this powder is 82 m2/g, corresponding to a particle size of ∼11 nm, which is in good agreement with TEM observations.

An aluminum (Al) target was laser ablated in a nitrogen (N2) atmosphere, producing aluminum nitride (AlN) powder. These powders were calcined at 900°C for 2 h. Powders were produced at various nitrogen pressures, and the calcined powders were tested for unreacted aluminum content, using differential thermal analysis (DTA). The AlN powder, produced at a laser fluence of 12 J/cm2 and a nitrogen pressure of 10.0 kPa (75 torr), showed no evidence of unreacted aluminum by DTA and was phase-pure AlN by X-ray diffraction (XRD). The surface area of this powder is 82 m2/g, corresponding to a particle size of ∼11 nm, which is in good agreement with TEM observations.

An aluminum (Al) target was laser ablated in an oxygen (O2) atmosphere, producing nanosize alumina (Al2O3) powder. The powder surface area decreased (and the particle size increased) with both increasing oxygen pressure and laser fluence. All powders produced had surface areas between 135 and 250 m2/g, corresponding to primary particle sizes ranging from 7 to 3 nm in radius. Phase evolution with temperature was studied via X-ray diffraction. These powders showed a direct transformation from γ- to α-alumina at approximately 1200°C, bypassing other transition alumina phases, while still maintaining small particle size ( 30 nm). Despite the nanosize particles, green densities equal to 54% of the skeletal density (i.e., true density of the solid phase) were obtained by uniaxial pressing at 40 MPa.

The accuracy of pore size information obtained from mercury porosimetry is often adversely affected by sample compression. Pore filling and compression are difficult to separate in a conventional intrusion experiment. However, we show that by performing an intrusion experiment on a sample sealed in an impermeable membrane (i.e., isostatic compaction), the effects of compression can be ascertained. Using this approach, the volume change associated with pore collapse compression was found to be proportional to P− 1 3 . Partial correction of intrusion data is accomplished by subtracting αP− 1 3 from the intrusion data, where α is a constant related to the solid matrix strength and is obtained from the slope in the linear region of a plot of volume versus P− 1 3 .

The physical structure (i.e., primary particle size, cluster fractal dimension) of a series of vapor-phase aggregates (fumed silica, carbon black) has been studied using mercury porosimetry. By employing an isostatic pressing technique, intrusion at low pressure is shown to be the result of cluster compaction for a range of Cab-O-Sil fumed silica and two carbon black samples. Analysis of the intrusion/compaction curve indicates fractal behavior with a D value of 2.5–2.6. Primary particle sizes determined via porosimetry support the theory that the nitrogen surface areas of fumed silica samples differ as a result of both particle size and surface roughness variation. The ratio of the mercury porosimetry-derived primary particle size to that determined from nitrogen adsorption was found to correlate with the surface fractal dimension as determined from scattering for both carbon black and fumed silica.

This paper reports gels containing a poly(borazinyl amine) and tetrahydrofuran processed by CO{sub 2} supercritical drying techniques followed by pyrolysis. The resulting BN ceramic aerogels are highly porous, and the microstructure, porosity, and surface area characteristics have been examined. The aerogels show excellent thermal stability exhibiting surface areas in excess of 350 m{sup 2}/g and porosities greater than 0.8 even when heated in argon at 1500{degrees}C for 8 h. By removing solvent via evaporation before supercritical drying, the mean pore radius can be varied between 3.6 and 10 nm.

The emerging capability to produce high average power (5--350 kW) pulsed ion beams at 0.2--2 MeV energies is enabling the authors to develop a new, commercial-scale thermal surface treatment technology called Ion Beam Surface Treatment (IBEST). This new technique uses high energy, pulsed ({

Surface treatment experiments using intense pulsed ion beams have demonstrated new capabilities for materials surface treatment. These experiments have confirmed corrosion resistance, surface hardening, amorphous layer and nanocrystalline grain size formation, metal surface polishing, controlled melt of ceramic surfaces, surface cleaning and oxide layer removal by rapid melting and resolidification. Deposition of beam energy in a thin surface layer allows melting of the layer with relatively small energies (1-10 J/cm2) and allows rapid cooling (109-1010 K/sec) and resolidification of the melted layer by thermal diffusion into the underlying substrate. At higher intensities (≥20 J/cm2), this technology can provide rapid ablation of material from targets followed by rapid, congruent deposition of polycrystalline thin films on substrates. This technology uses high energy pulsed (40–400 ns) ion beams to directly deposit energy in the top 2–20 micrometers of the surface of materials.

Summary form only given. Thin-film deposition by ion beam evaporation (IBE) is being studied at Los Alamos with an intense light ion beam generated with an applied-B/sub r/ magnetically insulated ion diode. For the first experiments, typical beam parameters are 0.4-MV, 35-kA, 0.5-/spl mu/s pulsewidth, H, C, and O ions generated with a Lucite flashover anode. Initial deposition experiments have been performed at relatively low energy fluences of about 10 J/cm/sup 2/ onto a variety of metallic and ceramic targets using a small portion of the beam. Beam-target interactions are modelled with the hydrodynamic code TITAN. YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta ceramic films, have been deposited onto a variety of room-temperature crystalline substrates. Rutherford backscattering analyses of the thin films indicate a deposition rate of 50 nm/pulse, which is orders of magnitude higher than typical laser deposition rates.

Diamond-like carbon films were prepared by high intensity pulsed ion beam ablation of graphite targets. A 350 keV, 35 kA, 400 ns pulse width beam, consisting primarily of carbon ions and protons, was focused onto a graphite target at a fluence of 15-45 J/cm2. Films were deposited onto substrates positioned in an angular array from normal to the target to 90° off normal. Deposition rates up to 30 nm per pulse, corresponding to an instantaneous deposition rate greater than 1 mm/sec, have been observed. Electrical resistivities between 1 and 1000 ohm·cm were measured for these films. XRD scans showed that no crystalline structure developed in the films. SEM revealed that the bulk of the films contain material with feature sizes on the order of 100 nm, but micron size particles were deposited as well. Both Raman and electron energy loss spectroscopy indicated significant amounts of sp3 bonded carbon present in most of the films.

Initial experiments on the evaporation from metallic and ceramic targets using a pulsed light ion beam source is reported. The source is an intense ion beam produced by a 1.2 MV, 300 kJ Anaconda generator which has been fitted with an extraction diode.Beam fluences of 10–20 J/cm2 give a deposition rate of about 30–50 nm per shot, for both brass and YBa2Cu3O7-x (1–2–3) targets. This is about 1000 times greater than comparable rates from pulsed laser deposition (PLD). Single-shot ablated 1–2–3 films, deposited on Si, were analyzed using RBS; the measured stoichiometry was close to 1–2–3 in favorable cases, but shot-to-shot reproducibili ty was poor.Approximately 1% of the available ion beam energy was utilized for these initial experiments. The potential for producing large area coatings from multi-cation targets and nanophase powders using pulsed ion beam deposition will be discussed.

From measurements of the change in nitrogen surface area as a function of the quantity of vapor preadsorbed on a solid powder or porous solid, surface/pore structural parameters may be obtained. The approach is demonstrated for water vapor adsorbed on various fumed silica powders, Vycor phase-separated glass, and several silica gels for surface roughness and micropore size distribution.

In a previous study of fumed silica by mercury porosimetry (ref. 1), we established an inverse dependence of the powder compressibility → on applied pressure P, heralded by power-law differential volume vs pressure curves. Independent small-angle neutron scattering (SANS) measurements, undertaken to establish microstructure, indicated a decreasing zero-angle intensity, I(q→0), with increasing sample compression. Preliminary analysis suggested that I(q7rarr;0) is proportional to the compressibility → . Since it is well known that I(q→0) is proportional to → for systems in thermodynamic equilibrium, our results implied an analogous relation for systems in mechanical equilibrium. However, the preliminary study was incomplete, lacking scattering data for a wide range of compactions. In this paper, we have tested this relationship, in the low pressure regime, by correlating the scattered neutron intensity from samples in various degrees of compaction. We find that, while the intensity does decrease with increasing compaction (after removing the effects due merely to greater sample density) as expected according to the compressibility analogy, the dependence is not the same as that found by mercury porosimetry. Lightly compressed fumed silica has been studied as a percolating system by several groups (refs. 2–4); our results pertain to states of greater compaction.

Poly(borazinylamines) have been processed in THF and toluene solvents and aerogel forms produced by supercritical drying methods. The polymer aerogels have been pyrolyzed and porous amorphous and crystalline BN monoliths have been produced. These have been characterized and effects of processing factors on surface area and pore structure are described.

Transient increases in plasma thyroxine (T4) concentrations and gill sodium-potassium-dependent adenosine triphosphatase ([Na+K]-ATPase) activity in captive alevins and young juveniles of pink salmon Oncorhynchus gorbuscha occurred during the period when development of salinity tolerance and seaward migration is observed. Plasma triiodothyronine (T3) concentration generally decreased during this time. Maximal values of plasma T4 concentration and gill (Na+K)-ATPase activity coincided with complete absorption of the yolk sac and final differentiation of the abdominal body wall. These findings suggest that a process similar to the smolt transformation of congeneric species may occur in juvenile pink salmon prior to seawater entry. Received March 23, 1983 Accepted August 8, 1983

An investigation of the properties of the ablation products from intense-pulsed ion beam impact on solid targets is described. Measurements and calculations of the properties of the ablation plume are presented and correlated with incident beam parameters. Experimental techniques include Thomson parabola particle spectroscopy to measure the incident ion beam atomic composition and the energy spectrum of each beam component, thermal imaging to measure the incident-beam energy density, time-resolved photography to measure the plume expansion time history and geometry, and time-resolved energy-density measurements of the plume. The results of a thermal transport model of the beam-target interaction are presented, and a detailed comparison with measurements is made.

Thin film deposition by ion beam evaporation is being studied at Los Alamos with an intense light ion beam generated in a focused applied-Br magnetically-insulated ion diode. H, C, and O ions are extracted from the Lucite flashover anode. The diode is powered directly by a Marx generator. For these first experiments, typical beam parameters are: 0.4 MV, 35 kA, 0.5-{mu}s pulsewidth. The beam is being used to produce and evaluate carbon films for use in field-emissive flat-panel displays. The films have been prepared by ablation of graphite targets with a 4 kJ ion beam focused to 30 {+-} 15 J/cm{sup 2}. Approximately 10 mg of material is ablated per pulse roughly consistent with a 1-D deposition and heat transport model. Films are deposited onto Si (100) and glass substrates. The films are fairly smooth with deposition rates as high as 50 nm/pulse. Four-point measurements give electrical resistivities of 10 to 100 {Omega}-cm, 10{sup 4} to 10{sup 5} times higher than graphite. Current-voltage measurements show good electron emission with Fowler-Nordheim scaling. X-ray diffraction shows no crystalline structure, while scanning electron microscopy reveals 100-nm feature sizes with a few 1-{mu}m particles. Raman spectroscopy and electron energy loss spectroscopy indicate that themore » films contain significant sp{sup 3} bonding. Glassy carbon is also produced under some conditions. Time-resolved photographs of ablation plume expansion will be presented. Also, time-resolved measurements of plume energy input to the substrates, using thin-film platinum resistive elements, have been made and will be presented.« less