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Biomedical subjects

M M Johnson

Publications and source records attributed to M M Johnson.

99 records · Page 6Linked to original sources
PubMedDate not supplied

Effect of respirator inspiratory resistance level on constant load treadmill work performance.

Respirator inspiratory resistance can affect performance times, especially when the experiment is optimized to elicit respiratory stress. Twelve subjects performed on a treadmill at constant speeds and grades chosen to result in performance times of 5-15 min. Six levels of inspiratory resistance were used, ranging from 0.78 to 7.64 cm H2O.sec/L. The results showed that performance times decrease linearly with resistance level, and no threshold resistance value is apparent. Inspiratory resistance also induces hypoventilation, with lower minute volumes and lower oxygen consumption values at higher resistances. These trends are also linear. From these results, there is no value for inspiratory resistance that can be given as a design goal. Other parameters such as weight and space may dictate filter resistance values, and these, in turn, will lead to determined performance degradations.

Adolescent↗
PubMedDate not supplied

Purchasing over-the-counter medications: the influence of age and familiarity.

This study examines the influence of age and type of over-the-counter (OTC) medications on decision-making processes leading to the selection of OTC medications. Manipulating type of OTC medication served as a way of examining subjects' familiarity with the decision domain. Thirty-six younger and thirty-six older adults answered questions regarding their OTC medication purchases, and completed a decision task in which they searched four computerized displays of product label information in order to select an antacid, a cold medication, a laxative, and a pain reliever. In general, older adults were slower to review information, more likely to have used OTC medications, and more organized in their searches for information. Specific to pair relievers, older and younger adults demonstrated similar information use and time to decision, and older adults specifically tailored the organization of their information searches when choosing pain relievers. Clearly, older adults selectively use product information on OTC medication packages, given adequate time to process information. Manufacturers' efforts directed at improving information availability should benefit older adults' decision processes.

Adult↗
PubMedDate not supplied

Individual differences in the voluntary use of a memory aid during decision making.

To characterize selective uses of external memory aids, 42 younger and 38 older adults made decisions and then completed individual difference measures. Experimental manipulation of the availability of a memory aid allowed examination of the effects of having a memory aid available as opposed to the spontaneous use of that aid. Use of the memory aid resulted in longer decision times, more requests for information, and less rechecking of already viewed information. Younger and older adults with high abstraction scores and older adults with high vocabulary scores were more likely to use the aid. Patterns of use differed in that younger adults used the aid in the middle of their information gathering and older adults used the aid toward the end. Making a memory aid available for use during decision making affected decision-making processes of older adults; use of the aid was associated with greater crystallized and fluid intelligence.

Adult↗
PubMedDate not supplied

Communication using a telephone while wearing a respirator.

Respirators have been found to degrade communication effectiveness when wearers speak face-to-face. However, little is known about communication effectiveness when using the telephone and wearing a respirator. Eleven pairs of subjects were asked to pronounce and identify words chosen from Modified Rhyme Test lists. Each word appeared on a computer screen in one room and the speaker said the word into the telephone. The listener in another room identified the word and typed it into a computer linked with the first. Subjects wore U.S. Army M40 full-facepiece air-purifying respirators with hoods. Three different speech diaphragm arrangements and two hood materials were tested. Results show that accuracy suffered by about 10% when respirators and hoods were worn compared with the control condition. Word identification speed was one-third to one-half of the control (no respirator or hood) condition depending on specific equipment worn.

Adolescent↗
PubMedDate not supplied

Effect of external dead volume on performance while wearing a respirator.

Respirator dead volume accumulates exhaled carbon dioxide and returns it to the respiratory system during subsequent inhalations. Because inhaled carbon dioxide is known to be a powerful respiratory stimulant and psychoactive gas, respirator dead volume would be expected to influence performance times while respirators are worn during work. This experiment was performed at intense levels of treadmill walking (80-85% VO2max) to demonstrate maximum sensitivity to respiratory stress. Six dead volume conditions (representing a range of 280 to 1,160 mL) were imposed on the subjects. Results show linear decreases in performance times and breathing apparatus comfort with increasing dead volumes. For each 350 mL of external dead volume, a 19% decrease of performance time and an 18% decrease in breathing apparatus comfort can be expected.

Acidosis, Respiratory↗
PubMedDate not supplied

The effect of callus removal on dynamic plantar foot pressures in diabetic patients.

Clinical observation suggests that neuropathic foot ulceration frequently occurs beneath plantar callosities and in areas of high dynamic shear and vertical stress underneath the foot during walking. Seventeen diabetic patients had dynamic foot pressure measurements made before and after the removal of a total of 43 forefoot plantar callosities. Peak pressures (mean +/- SE) in the treated areas were reduced by 26% from 14.2 +/- 1.0 to 10.3 +/- 0.9 kg cm-2 (p less than 0.001), with reductions at 37 of the 43 sites and in all patients. Mean heel pressures were not significantly different (5.0 +/- 0.6 vs 4.9 +/- 0.6 kg cm-2). These results suggest that callus may act as a foreign body elevating plantar pressures and that a significant reduction in pressure is achieved by local chiropody treatment.

Analysis of Variance↗
PubMedDate not supplied

Effects of family disruption on Southeast Asian refugee women.

Identifying refugee women at a high risk of depression, anxiety and post-traumatic stress is an important role of the nurse, so that appropriate interventions--including family and community support--can be implemented. Below, an assessment of Southeast Asian refugee women experiencing emotional distress from the disruption of family ties that occurred during war, escape and resettlement.

Adaptation, Psychological↗
PubMedDate not supplied

Compliance with the screening mammography program of British Columbia: will she return?

OBJECTIVE: To identify factors associated with compliance in the Screening Mammography Program of British Columbia (SMPBC). METHOD: Factors associated with rescreening within 18 months (annual compliers) and between 18 to 36 months later (late compliers) were identified in a cohort of SMPBC screenees using a self-administered questionnaire. RESULTS: Fewer than half of women initially screened within the SMPBC were annual compliers, nearly 40% not returning by 3 years. In women age 50+ years, annual compliers tended to have no prior mammography, no prior breast pain, a physician referral to SMPBC, and a normal initial SMPBC mammogram. Late compliers also tended to have no prior mammography, a physician referral, and a normal initial SMPBC mammogram. CONCLUSIONS: Several modifiable factors associated with compliance were identified: a physician referral to the program and possibly subsequent referral back to the program after workup for an abnormal mammogram.

Adult↗