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Biomedical subjects

B L Davis

Publications and source records attributed to B L Davis.

At least 55 records · Page 3Linked to original sources
PubMed1989

Chevron osteotomy of the first metatarsal for hallux valgus.

A retrospective study of 50 chevron osteotomies evaluated subjective and objective functional and cosmetic results, which were in keeping with other reported studies--i.e. satisfactory subjective cosmesis in 98%; excellent or good pain relief in 84%; and satisfactory objective cosmesis in 84%. The correction of the 1st intermetatarsal angle averaged 3.3 degrees, and that of the metatarsophalangeal valgus averaged 15 degrees. Average active range of motion of the 1st metatarsophalangeal joint was 60 degrees. Complications were generally mild and asymptomatic, and were usually iatrogenic. The findings of this study, together with information gained from a concomitant stress analysis, led to recommendations regarding operative technique.

Adult↗
PubMed1986

Granuloma-related hypercalcemia in lipoid pneumonia.

A patient with hypercalcemia, suppressed serum PTH levels, and elevated serum levels of calcitriol was found to have a granulomatous lipoid pneumonia due to chronic aspiration of a "vaporizing ointment." After the surgical removal of the largest granuloma, the serum calcium and calcitriol levels rapidly returned to normal. This is a new instance of granuloma-induced hypercalcemia, probably mediated by the activation of vitamin D by cells of the granulomatous reaction.

Aged↗
PubMed1982

Occupational dermatitis associated with straw itch mites (Pyemotes ventricosus).

A 1981 outbreak of dermatitis in Austin, Tex, was traced to occupational exposure to wheat infested with the straw itch mite, Pyemotes ventricosus; the wheat was being sold for decorative purposes by an imported-goods store located on the second floor of a large, modern, shopping mall complex. In addition to an extensive varicelliform skin eruption, one employee also had chills, fever, malaise, diarrhea, and anorexia associated with her exposure to these mites. The straw itch mite has been associated with several large epidemics of dermatitis during the 19th and 20th centuries. This outbreak is the third reported in Texas since 1961. Physicians should consider the possibility of straw itch mite infestations of products brought into the home or places of employment when they observe patients with a varicelliform or chigger-bite-like dermatitis, which may be accompanied by constitutional symptoms.

Adult↗
PubMed1982

The PCP epidemic: a critical review.

The scientific literature on PCP (phencyclidine) was reviewed with a view to determining whether or not current knowledge coincides with the picture of PCP presented by the popular media. The media portray PCP as an insidious drug whose use has reached almost epidemic proportions among American youth. Serious adverse reactions, including psychosis and violent behavior, are seen as common if not inevitable consequences of use. The literature indicates that this picture of PCP is not justified. Both the prevalence of use and the relative frequency of severe adverse effects appear to have been overstated by the media.

Adolescent↗
PubMedDate not supplied

Decomposition of superimposed ground reaction forces into left and right force profiles.

The process of collecting ground reaction force data by mounting a forceplate beneath a treadmill belt has the advantage that numerous walking trials can be analyzed without the problem of subjects 'targeting' their footsteps. However, a potential problem is that the measured forces represent a summation of bilateral force profiles during the double support phase of walking. To address this issue, an algorithm is described for decomposing superimposed ground reaction force data into individual left and right profiles. It is based on an examination of the side-to-side oscillations of the measured center of pressure (CoP). Whenever the measured CoP exceeds a certain threshold, it is assumed that the person is being supported by a single limb, and the measured GRF data reflect the forces under that limb. Conversely, when the measured CoP indicates that both feet are on the treadmill, it is assumed that the location of the individual CoP under each foot is given by wL2 and wR2. These quantities reflect the greatest excursion of the measured CoP towards the left and right sides of the forceplate, respectively. With this assumption, individual GRF profiles can be calculated by means of solving two simultaneous equations--one describing the equilibrium of forces in the vertical direction, and one describing the equilibrium of moments about an antero-posterior axis of the forceplate. The algorithm describing this procedure is simple enough to be implemented on a spreadsheet and yields estimates for average force, impulse, peak force and stance time that are typically within 3% of the true values.

Adult↗
PubMedDate not supplied

Segmented force plate (SFP) software package for clinical use.

A gait analysis system is described. It is designed for clinical use as well as research purposes. The system is simple to operate and can be used by non-computer specialist. The design philosophy is straightforward and allows for easy adaptation to other systems. Samples of the output are presented.

Electronic Data Processing↗
PubMedDate not supplied

The motor core of speech: a comparison of serial organization patterns in infants and languages.

Comparison of serial organization of infant babbling and early speech with that of 10 languages reveals four movement-related design features reflecting a deep evolutionary heritage: (1) the cyclical consonant-vowel alternation underlying the syllable, a "Frame" for speech consisting of mandibular oscillation, possibly evolving from ingestive cyclicities (e.g., chewing) via visuofacial communicative cyclicities (e.g., lipsmacks); (2) three intracyclical consonant-vowel co-occurrence preferences reflecting basic biomechanical constraints-coronal consonants-front vowels, dorsal consonants-back vowels, and labial consonants-central vowels; (3) a developmental progression from above-chance to below-chance levels of intercyclical consonant repetition; (4) an ease-related labial consonant-vowel-coronal consonant sequence preference for word initiation. These design features presumably result from self-organizational responses to selection pressures, primarily determined by motor factors. No explanation for these design features is available from Universal Grammar, and, except for feature 3, perceptual-motor learning seems to have only a limited causal role in acquisition of any design feature.

Child↗
PubMedDate not supplied

Prosodic correlates of stress in babbling: an acoustical study.

Prelinguistic babbling often seems remarkably speech-like, not because it has recognizable words but because it seems to have adult-like prosody. To quantify this impression, we compared disyllabic sequences from five infants and five adults in terms of the use of frequency, intensity, and duration to mark stress. Significantly larger values for the three acoustic variables were observed on stressed than on unstressed syllables independent of syllable position for both groups. Adults showed the correlates of utterance final syllables--lower f0, lower intensity, and longer duration; infants showed only decrease in intensity. Ratios for stressed to unstressed syllables and participation of the three variables in stress production in individual disyllables were highly similar in both groups. No bias toward the English lexical trochaic stress pattern was observed. We conclude that infants in English environments produce adult-like stress patterns before they produce lexical items, which specify stress. Acoustic and perceptual analyses are used to explore stress marking by prelinguistic infants in an English language environment. Results show that infants employ the three acoustic correlates of stress in individual syllables in a manner largely similar to that of adult speakers, although they do not show second-syllable declination effects or an English language trochaic stress bias.

Adult↗
PubMedDate not supplied

An embodiment perspective on the acquisition of speech perception.

Understanding the potential relationships between perception and production is crucial to explanation of the nature of early speech acquisition. The 'embodiment' perspective suggests that mental activity in general cannot be understood outside of the context of body activities. Indeed, universal motor factors seem to be more responsible for the distribution of early production preferences regarding consonant place and manner, and use of the vowel space than the often considerable cross-language differences in input available to the perceptual system. However, there is evidence for a perceptual basis to the establishment of a language-appropriate balance of oral-to-nasal output by the beginning of babbling, illustrating the necessary contribution of 'extrinsic' perceptual information to acquisition. In terms of representations, at least one assumption that segmental units underlying either perception or production in early phases of acquisition may be inappropriate. Our work on production has shown that the dominant early organizational structure is a relatively unitary open-close 'frame' produced by mandibular oscillation. Consideration of the role of 'intrinsic' (self-produced) perceptual information suggests that this frame may be an important basis for perceptual as well as production organization.

Humans↗