Biomedical subjects

S M Doyle

Publications and source records attributed to S M Doyle.

22 records · Page 2Linked to original sources

PubMed1985

Radon entry into houses having a crawl space.

The transport of 222Rn from soil, through a vented crawl space, and into the living space of single-family residences was studied. Two houses were monitored in detail for periods of 5 and 7 weeks. With crawl space vents open, the average indoor 222Rn concentrations were 1.2 and 0.6 pCi 1.-1 (44 and 22 Bq m-3); with the vents sealed the averages rose to 2.2 and 1.0 pCi 1.-1 (81 and 37 Bq m-3). The data suggest that, of the Rn released into the crawl space from the soil beneath the house, a significant fraction, perhaps 50% or more, enters the living space. The effect of 3 meteorological parameters--wind speed, indoor-outdoor temperature difference, and rate of barometric pressure change--on Rn concentration and entry rate were examined. In 1 of the houses a higher temperature difference corresponded to a higher indoor concentration, suggesting that the increased infiltration rate is more than compensated by an increase in the Rn entry rate. On the other hand, a high wind speed tended to reduce the indoor concentration, presumably by increasing both cross-ventilation of the crawl space and the infiltration rate of the living space. Results suggest that Rn transport into the crawl space of at least 1 of the houses occurred by pressure-driven flow, rather than solely by molecular diffusion. The diffusion coefficient of 222Rn through polyethylene sheeting, such as was present on the ground beneath this house, was measured in the laboratory and found to range from 0.65 X 10(-7) cm2 s-1 at 11 degrees C to 1.6 X 10(-7) cm2 s-1 at 25 degrees C, implying that the maximum diffusive flux through the sheet was many times smaller than that necessary to account for the rate of Rn entry into the house. A third house was studied using a tracer gas injected into the crawl space at a controlled rate. The fraction of air leaving the crawl space that entered the living space ranged from 0.3 to 0.65, in good agreement with results for Rn transmission in the other 2 houses, assuming that the 222Rn flux into the crawl space was comparable to that which would have resulted from molecular diffusion from soil having a 222Rn diffusion length of 1.0 m. By sealing leaks in the floor of this house, the average infiltration rate was reduced by 25%, but the indoor concentration of the tracer gas remained constant.

Air Pollutants↗

PubMed1984

Time-averaged indoor Rn concentrations and infiltration rates sampled in four U.S. cities.

Indoor Rn concentrations, measured in 58 houses during a 4- to 5-mon period during the winter and spring of 1981-1982, varied from 0.1-16 pCi l-1 (4-590 Bq m-3). Average infiltration rates were determined for each house during the same period, based on a measurement of the effective leakage area and an infiltration model, and found to range from 0.2-2.2 air changes per hour (h-1). Indoor Rn concentrations correlated poorly with infiltration rates for houses within each city as well as for the entire sample. Differences in Rn entry rates among houses thus appear to be more important than differences in infiltration rates in determining whether a house has high indoor Rn levels, consistent with previous indications from grab-sample measurements. Radon entry rates and indoor Rn concentrations were generally higher in houses in Fargo, ND, and Colorado Springs, CO, than in houses in Portland, ME, and Charleston, NC.

Air Pollutants↗

PubMedDate not supplied

Symptomatic talonavicular coalition.

Talonavicular coalition is reported as an asymptomatic congenital anomaly of the foot that is noticed incidentally on radiographs of the foot, and is often associated with symphalangism, clinodactyly, ball-and-socket ankle joint, a great toe that is shorter than the second toe, and an autosomal dominant inheritance pattern. We describe here three patients with five involved feet. All three patients had chronic foot pain not secondary to trauma, and all five feet required treatment to alleviate the pain.

Adolescent↗

PubMedDate not supplied

Resection arthroplasty of the hip for patients with cerebral palsy: an outcome study.

Thirteen patients (18 hips) with cerebral palsy and painful hip subluxation or dislocation underwent proximal femoral resection-interposition arthroplasty (PFRIA) as a salvage procedure for intractable pain or seating difficulty. Eleven patients (14 hips) had a prior failed soft-tissue or bony reconstruction. The average age at surgery was 26.6 years (range, 10.7-45.5 years), and average follow-up was 7.4 years (range, 2.2-20.8 years). All patients/caregivers noted significant improvement in subjective assessment of pain after the surgery. Upright sitting tolerance improved from an average preoperative value of 3.2-8.9 h postoperatively (p < 0.01). Four patients who were unable even to sit in a customized wheelchair before the operation could be easily seated in a custom chair after surgery. Hip range of motion including flexion, extension, and abduction was significantly improved postoperatively (p < 0.05). Single-dose radiation therapy was used postoperatively for five hips and resulted in a significantly lower grade of heterotopic ossification at final follow-up (p < 0.005). Skeletal traction in the postoperative period did not prevent proximal migration of the femur compared with skin traction. Maximal pain relief was achieved at an average of 5.6 months postoperatively (range, 0.03-14 months). Complications included transient postoperative decubitus ulceration (four patients), pneumonia (two patients), and symptomatic heterotopic bone (two patients). The significant improvements in pain management, sitting tolerance, and range of motion suggest that PFRIA is a reasonable salvage procedure for the painful, dislocated hip in cerebral palsy. Resolution of pain may not be immediate, as was noted in this series.

Adolescent↗