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Biomedical subjects

F A Weber

Publications and source records attributed to F A Weber.

8 recordsLinked to original sources
PubMed2005

Radiation-driven hydrodynamics of high- hohlraums on the national ignition facility.

The first hohlraum experiments on the National Ignition Facility (NIF) using the initial four laser beams tested radiation temperature limits imposed by plasma filling. For a variety of hohlraum sizes and pulse lengths, the measured x-ray flux shows signatures of filling that coincide with hard x-ray emission from plasma streaming out of the hohlraum. These observations agree with hydrodynamic simulations and with an analytical model that includes hydrodynamic and coronal radiative losses. The modeling predicts radiation temperature limits with full NIF (1.8 MJ), greater, and of longer duration than required for ignition hohlraums.

Journal Article↗
PubMed2004

Measurement of the absolute hohlraum-wall albedo under ignition foot drive conditions.

We present measurements of the absolute albedos of hohlraums made from gold or from high-Z mixtures. The measurements are performed over the range of radiation temperatures (70-100 eV) expected during the foot of an indirect-drive temporally shaped ignition laser pulse, where accurate knowledge of the wall albedo (i.e., soft x-ray wall reemission) is most critical for determining capsule radiation symmetry. We find that the gold albedo agrees well with calculations using the supertransition array opacity model, potentially providing additional margin for inertial confinement fusion ignition.

Journal Article↗
PubMed1990

Long-term results of revision total hip arthroplasty.

A total of 138 revision hip arthroplasties in 134 patients, all operated upon by one surgeon, were followed for an average of 7.4 years. The overall results were reasonable, with good to excellent Mayo hip scores in 62% and little or no pain in 86%. These results were independent of body weight, age, primary diagnosis and type of arthroplasty used. The incidence of radiological loosening was alarming, though comparable to that found in other series. Our findings indicate that it may be wise to replace both components even when, after careful assessment before and during operation, one of them seems to be securely fixed.

Adult↗
PubMed1986

Revision of infected total hip arthroplasty.

Extension of infection down the medulla of the femur to the supracondylar region may occur in cases of chronic infected total hip arthroplasty. Because this cannot always be identified before operation, the femur should be reamed and flushed proximally from the lateral condyle in all cases where there is suspicion of infection around the femoral component. Where infection is unequivocal and extensive, a period of irrigation and suction drainage is advisable before final total hip arthroplasty. After the prosthesis has been inserted in either one or two stages, it is wise not to rely on antibiotic cement mixtures alone but to monitor the bacterial flora and prescribe local antibiotic therapy accordingly.

Anti-Bacterial Agents↗
PubMed1975

A radiological study of fractures of acrylic cement in relation to the stem of a femoral head prosthesis.

The incidence and prognostic significance of fractures of acrylic cement related to the stem of a femoral head prosthesis in total hip replacement are examined. These fractures are demonstrated when the cement has been rendered radio-opaque by the addition of barium sulphate. One and a half percent of the radiographs of 6,649 patients showed these fractures, which were sometimes associated with subsidence of the prosthesis. Fracture of the cement was usually evident at the six-month post-operative review, if it occurred at all. This radiological complication was devoid of symptoms in the majority of cases and tended to occur in patients with excellent functional recovery. In a minority of patients pain in the thigh during the first six months seemed likely to be explained by this fracture. Slight subsidence of the prosthesis in the cement bed appeared to result in a new and final position of stability. The prognosis was very good; only when separation of the fracture exceeded about 4 millimetres was the prognosis doubtful, in which case a chronic deep infection might be suspected. Possible mechanical and structural causes of fracture of the cement are discussed.

Aged↗
PubMed1973

Spinal stenosis.

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Adult↗