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Biomedical subjects

W R Nelson

Publications and source records attributed to W R Nelson.

36 records · Page 2Linked to original sources
PubMed1984

Primary and leakage radiation calculations at 6, 10 and 25 MeV.

Primary and leakage x-ray spectra for typical clinical accelerators have been calculated using the EGS Monte Carlo code for 3 energies (6, 10 and 25 MeV) and 4 angles (0 degree, 45 degrees, 90 degrees and 135 degrees). Broad-beam transmission curves have been calculated for ordinary concrete using the MORSE program with the EGS spectra as input. A simple analytical model, which is shown to agree rather well with both experimental data and with the MORSE results, is presented and initial and subsequent tenth-value layers are extracted. Finally, the photon spectrum after the concrete shield is obtained with MORSE.

Monte Carlo Method↗
PubMed1983

A trauma centre--what is involved.

A trauma centre must provide a system of care. This begins as soon as possible after the injury and continues until the patient returns to his usual daily activities. Because of necessity, such trauma centres deal with those who have serious or multiple injuries. Then it is important to provide early and appropriate care from the outset and sometimes before definitive management is undertaken. Care must be expeditious always as this reduces morbidity and mortality. We consider management to be divided into (a) before admission, (b) care in hospital, and, lastly (c) rehabilitation or other measures after discharge. This paper focuses on what we describe as the "golden hour" which is that crucial first hour after admission. Nevertheless, to achieve optimal results the whole system of care is vital. It is in that initial hour, however, that our radiologic colleagues are most clearly and actively involved.

Accidents↗
PubMed1980

Pneumatic power supply for intravenous infusions.

The pneumatic power supply (PPS) has been used as the driving device for the pneumatic blood pump during the resuscitation of more than 15 hypovolemic patients. The device has been found to be safe and easy to use. By virtue of its semiautomatic function, members of the resuscitation team are free to perform other duties. Previously, these individuals would have been required to maintain an adequate driving pressure in the infusion pumps.

Chlorofluorocarbons, Methane↗
PubMed1977

Improved staining characteristics of serum lipids after halogenation and esterification of thin-layer chromatograms.

We describe a procedure for treatment of thin-layer chromatographic serum lipid patterns so that they may be stained by dyes for evaluation by densitometry. After development of the chromatogram [Clin. Chem. 18, 384 (1972)] the plates are dried and sprayed with butyryl chloride. This esterifies the free cholesterol. After drying, the plate is treated with iodine monobromide, to add iodline to the double bonds. The triacylglycerols (triglycerides), cholesterol esters, free cholesterol, and phospholipids are now all in the form of esters with no unsaturated double bonds. The free fatty acids are also now saturated. The chromatogram is now stained with basic fuchsine in acetate buffer (0.1 mol/liter, pH 5.0). Excess stain is removed with a buffered solution of guanidine hydrochloride. Erythrosine B may also be used. With basic fuchsine the background will be a uniform pink. With erythrosine B the background is white, but the stain tends to be washed out of the free fatty acids. The chromatograms are evaluated by densitometry, with use of a 540-nm filter for basic fuchsine and a 520-nm filter for erythrosine B. The stained chromatograms and densitometric scans accurately represent the relative concentration of the various lipid fractions as compared to that of an internal standard, and correlate with the nature of the disease being explored.

Adult↗
PubMed1975

In vitro inhibition of endotoxin induced platelet aggregation with hydrocortisone sodium succinate (Solu-Cortef).

Citrated canine platelet rich plasma stimulated with ADP, thrombin, collagen and E. coli endotoxin demonstrated platelet aggregation when measured with Payton aggregometer. Following incubation with hydrocortisone sodium succinate (Solu-Cortef) the same platelet rich plasma did not undergo platelet aggregation when stimulated by these agents. Solu-Cortef added to platelet rich plasma during ATP, thrombin, collagen and endotoxin stimulated platelet aggregation resulted in a reversal of the optical density suggesting deaggregation. These in vitro observations support the beneficial effects observed when steroids are administered in vivo to experimental or clinical shock.

Adenosine Diphosphate↗
PubMedDate not supplied

Axillary metastases from carcinoma of the larynx: a 25-year survival.

Axillary metastases from squamous cell carcinomas of the head and neck are usually considered signs of incurability. A case is presented in which the patient developed well-differentiated squamous cell carcinoma in bilateral axillary nodes following total laryngectomy and radical neck dissection for advanced recurrent squamous cell carcinoma of the larynx. Bilateral axillary dissection was performed on this patient followed by a second neck dissection for metastasis. The patient remained well for 25 years free of disease, dying of a massive heart attack. One report of this phenomenon has been found in the literature. The authors conclude that radical axillary dissection should be considered in selective cases of well-differentiated carcinoma in axillary nodes from a controlled primary in the head and neck mucosa when no other signs of dissemination have been found. A brief review of cervical and axillary lymphatic anatomy is included.

Axilla↗
PubMedDate not supplied

Structured methods for identifying and correcting potential human errors in space operations.

Human performance plays a significant role in the development and operation of any complex system, and human errors are significant contributors to degraded performance, incidents, and accidents for technologies as diverse as medical systems, commercial aircraft, offshore oil platforms, nuclear power plants, and space systems. To date, serious accidents attributed to human error have fortunately been rare in space operations. However, as flight rates go up and the duration of space missions increases, the accident rate could increase unless proactive action is taken to identity and correct potential human errors in space operations. The Idaho National Engineering and Environmental Laboratory (INEEL) has developed and applied structured methods of human error analysis to identify potential human errors, assess their effects on system performance, and develop strategies to prevent the errors or mitigate their consequences. These methods are being applied in NASA-sponsored programs to the domain of commercial aviation, focusing on airplane maintenance and air traffic management. The application of human error analysis to space operations could contribute to minimize the risks associated with human error in the design and operation of future space systems.

Accidents, Aviation↗
PubMedDate not supplied

Unwanted photon and neutron radiation resulting from collimated photon beams interacting with the body of radiotherapy patients.

Monte Carlo calculations have been made to determine the energies delivered by photons and neutrons to the human body irradiated by collimated photon beams. The beams were monoenergetic and ranged from 100 keV to 40 MeV. The energy deposition in the body was sorted into two regions: inside and outside the irradiated volume. Most of the results obtained were for a beam size of 100 cm2 although some calculations were also made to 600 cm2 beams. The effect of beam size on energy deposition in the two regions was investigated for 60Co gamma rays. Graphs are presented which give the integral doses delivered by neutrons and photons to the two regions for therapy beams of various energies. These graphs can be used to calculate the integral doses which are delivered inside and outside the treatment volume for photon spectra from most medical accelerators. Calculations of energy deposition were also made for the spectra from two particular accelerators. These were done using Monte Carlo as well as by simply "folding" the spectra into the results for monoenergetic photons. The results obtained by both methods were in good agreement and indicated that the integral doses deposited outside the treatment volume by neutrons are more than two orders of magnitude smaller than those deposited by scattered photons.

Cobalt Radioisotopes↗