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Biomedical subjects

C R Peters

Publications and source records attributed to C R Peters.

At least 19 recordsLinked to original sources
PubMed1998

Archaeological predictions for hominid land use in the paleo-Olduvai Basin, Tanzania, during lowermost Bed II times.

We present a preliminary predictive model of Oldowan stone artefact and scavenged larger mammal bone assemblages for 11 landscape facets modeled earlier to occur across a large portion (> 300 km2) of the paleo-Olduvai Basin during lowermost Bed II times. This second phase of model-building is based on our earlier characterizations of the basin's landscape ecostructure and the inter-facet distribution of key resources and hazards probably encountered by Late Pliocene hominids (Peters & Blumenschine, 1995, 1996). Our current extension of the model of hominid-landscape interactions specifies additional theoretical components, including: (1) the assumed capabilities of Oldowan hominids (presumably Homo habilis, primarily); (2) the landscape-facet-specific tasks they carried out; (3) the immediate stone and bone task residues they produced; and (4) the predicted composition, condition, density, and clustering of stone artefact and butchered and unbutchered bone assemblages for each facet. We develop ecological linkages between these new and formerly reported modeling components, the most fundamental of which is the facet-specific degree of tree/shrub cover abundance, and the correlated degree of competition among larger carnivores and hominids for scavengeable larger mammal carcasses. These factors condition variability among landscape facets in scavenging opportunities encountered by hominids, which in our model is the major predictor of bone and stone artefact assemblage composition. The predictive value of scavenging reflects the bias of paleoanthropological traces toward technology and butchery in their landscape context, but the model is surprisingly insensitive to what are usually thought to be critical social components of hominid land use. The predictions for the traces of hominid-landscape interactions modeled herein can be tested in the future against the landscape archaeological sample being excavated from lowermost Bed II by the Olduvai Landscape Paleoanthropology Project.

Animals↗
PubMed1996

Femtomolar sensitivity using a channel-etched thin film waveguide fluoroimmunosensor.

A dual channel, evanescent fluoroimmunoassay format is used to detect femtomolar analyte concentrations (i.e. less than 1 part per trillion [w/w]) on an etched channel siliconoxynitride thin film integrated optical waveguide. Two assays are used to demonstrate the dose-response behaviour of the sensor: (1) a direct assay of a fluorescently-labeled protein ligand binding to an immobilized protein receptor, and (2) an indirect sandwich assay of a non-fluorescent protein ligand binding to an immobilized protein receptor, as detected by the binding of a fluorescently-labeled secondary receptor protein. A red-emitting cyanine dye (Cy-5), which minimized background fluorescence and scatter losses of the waveguide, was used in both assays. To our knowledge, this is the first report of femtomolar sensitivity in an immunosensing instrument.

Biosensing Techniques↗
PubMed1994

Seed-breaking forces exerted by orang-utans with their teeth in captivity and a new technique for estimating forces produced in the wild.

Orang-utans (Pongo pygmaeus) at the Singapore Zoological Gardens were presented with two thick-shelled edible seeds, Mezzettia parviflora (Annonaceae) and Macadamia ternifolia (Proteaceae) in order to estimate their maximum bite forces. The orang-utans could break the Macadamia seeds in one bite, while those of Mezzettia required repeated attempts. Examination of shell fragments showed that many had scratches and some had clear, but small (ca. 1-2 mm diameter), impressions on them. Building upon this information, semi-imitative tests were performed on the seeds in a universal testing machine by loading them in compression with either flat plates or metal casts of orang-utan cheek teeth. The maximum forces required to break the seeds were similar with both the flat plates and the metal teeth; the average for the Macadamia seeds being about 2,000 N (which forms a minimum estimate for the maximum bite forces in orang-utans) and for the Mezzettia seeds, 6,000 N. The work done with the metal teeth was much greater than with the plates. A mechanical analysis showed that this extra work went into producing permanent impressions ("bite marks") in the shell with the tooth cusps. These impressions were larger than those found on the shells of seeds bitten by the orang-utans. Nevertheless, it is shown theoretically that the size of these indentations can given an estimate of the bite forces used. The maximum force developed in the machine tests with the metal teeth was correlated with the force calculated from analysis of the bite marks. The method is suitable for use in field studies where the marks left on remnants of hard foods eaten by primates may be used to estimate, very roughly, the forces used to produce them.

Animal Feed↗
PubMed1993

Hypertrophy of the acetabulo-cristal buttress in Homo sapiens.

In the early 1970s, excavation at the King site, a contact period Mississippian village in northwest Georgia, yielded the skeletal remains of a robust male (King 65) possessing marked hypertrophy of the acetabulo-cristal buttress. The buttress is morphologically similar to that of Plio-Pleistocene Homo but it is accompanied by an anatomically modern degree of thickening of the gluteal table of the ilium. Although the degree of cortical thickness of the gluteal table of the ilium is apparently species-specific, hypertrophy of the acetabulo-cristal buttress is developmental and may be expressed in all species of Homo.

Acetabulum↗
PubMed1989

Rhytidectomy.

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Humans↗
PubMed1989

Otoplasty.

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Child↗
PubMed1989

Ethical issues in professional advertising.

Physician advertising has received considerable attention since the courts decided in favor of the Federal Trade Commission (FTC) in its initial complaint against the American Medical Association in the 1970s. Continued investigations by the FTC into AMA opinions on advertising and publicity have promulgated a new freedom in advertising by physicians. False and deceptive advertising though is the grounds for court action as well as license revocation. This is an attempt to analyze where physician advertising is most prevalent, which physicians are doing it and why.

Advertising↗
PubMed1987

Nut-like oil seeds: food for monkeys, chimpanzees, humans, and probably ape-men.

The hypothetical hyperrobust australopithecine gnathic nutcracker adaptation is reexamined in light of ecobotanical information on edible wild nuts provided by the flora of tropical and subtropical Africa. The nut producing species are tree-forms. Those of the forest region do not as a rule produce fruits with edible mesocarps. In contrast, the woodland savanna species (particularly in the Zambezian region) characteristically provide an important whole fruit, i.e., a nutritious mesocarp in addition to edible oil-rich nut seeds. These fruits drop from the tree before they are fully mature and go through the final ripening phase on the ground. They are important seasonal foods for a variety of vertebrates, including primates, elephants, and antelope. Altogether the nuts exhibit a broad range of toughness values, measured here as strength under compression. The woodland nuts are not as tough (177-934 kg force, breaking load) as those of the tropical forest (192-1,673 kg force). The seed-predators of the woodland species include squirrels, baboons, warthogs, and parrots. Paleoecological analyses indicate that it was the woodland nuts that were probably available to Australopithecus boisei and A. robustus. Preliminary estimates of adult male gnathic nut-cracking capabilities suggest that A. boisei could have orally cracked a significant portion of the woodland nuts. In spite of this, ecobotanical data indicate that we can probably reject the hypothesis that these hominids were year-round gnathic nut-cracking specialists. Both the indirect and direct evidence support this conclusion.

Africa↗
PubMed1986

Emergency care of the injured hand.

A multitude of hand injuries are occupationally related. The scope of such injuries and the appropriate initial care of each is discussed. The ultimate outcome following an occupationally related hand injury is frequently determined by the initial care rendered.

Amputation, Traumatic↗
PubMed1983

Slow cooker vs. oven preparation of meat loaves and chicken.

Meat loaves and chickens prepared by recommended methods for a slow electric cooker were not in the hazardous temperature zone long enough to allow appreciable growth of bacteria that might cause food-borne illness. Total plate counts were reduced to a greater extent than they were when meat loaves and chickens were prepared by conventional methods in a gas oven. Presumptive coliforms, C. perfringens, and coagulase positive staphylococci were not detected after either method of cooking. Other parameters of quality indicated that conventional methods of baking meat loaves and roasting chickens were superior to preparation in a slow electric cooker. Drip losses were significantly greater, as were total cooking losses (except for total losses for chickens in Experiment 2), when a slow electric cooker was used. All mean palatability scores except for interior color in meat loaves and tenderness in chickens were significantly higher after preparation in an oven. Significantly more thiamin was retained in oven-cooked meat loaves and chickens.

Animals↗
PubMed1982

Electron-optical microscopic study of incipient dental microdamage from experimental seed and bone crushing.

No living analogue exists for the hypothetical early hominid hard/tough-seed, coarse-root-eating, and bone-crushing masticatory adaptation. To investigate possible microdamage/microwear to dental enamel caused by such usage, puncture-crushing experiments were carried out on single human teeth, using an Instron compression apparatus on the following six test materials: Makapansgat Limeworks chert (e.g., taphonomy), fresh steer longbone, mongongo nuts, Grewia berries, Carob beans, and wild-onion bulbs. Pairs of extracted unworn third molars were utilized, with one tooth acting as the control. The teeth were mounted, ultrasonically cleaned, and two-stage replicas made with a vinyl polysiloxane elastomer and araldite epoxy resin. After Instron loading and materials failure (1.2-395.0 kg) the test items and the crowns were prepared for comparison with scanning electron microscopy and dispersive x-ray elemental analysis and mapping. The results revealed that although grit adhering to food item surfaces caused microscratches (0.1-1.0 micron wide) similar in appearance to those caused by opal phytoliths in grasses, the dicotyledonous seed coats per se were unable to score enamel. This suggests microscratch morphology alone may not provide a reliable indication of food type. In some cases puncture-crushing of bone and hard legumes produced a localized microfracture pattern (crazing with cracks less than or equal to 0.1-1.0 micron wide) that was readily distinguishable from the simulated taphonomic damage caused by chert fragments, suggesting only analysis of enamel mistaphonomic damage caused by chart fragments, suggesting analysis of enamel microfracture patterns may provide clues as to early hominid dietary adaptations.

Bone and Bones↗
PubMed1980

The influence of vitamin E on capsule formation and contracture around silicone implants.

An attempt was made to determine if the tissue response to surgical trauma and foreign body stimulus (silicone implants) could be altered using vitamin E in rats. The animals were divided into four groups: Group A served as controls, Group B were treated by intramuscular vitamin E, Group C were treated topically with vitamin E around the prosthesis, and Group D were treated topically with croton oil around the prosthesis. The animals in each group were killed at 2 week, 1 month, and 3 months intervals. The intraprosthetic pressure in each prosthesis was recorded using a strain gauge transducer. The capsules were then removed and examined histologically using a light microscope and the thickness of pseudocapsules was measured with an ocular micrometer. In Group B significantly thinner pseudocapsules were observed at 2 weeks, but there was no comparable difference either in thickness or degree of contracture (as measured by intraprosthetic pressures) between Groups A and B at 2 months and 3 months. In Group C, the pseudocapsules were significantly thicker at all tested periods and showed noticeable contracture at 3 months. In group D the pseudocapsules were thickest and cellular infiltrate more marked than in the other groups.

Administration, Topical↗
PubMed1980

The combined multidisciplinary approach to invasive basal cell tumors of the scalp.

Deeply invading tumors of the scalp present numerous extirpative and reconstructive problems requiring the combined expertise and skills of both medical and surgical disciplines. We have employed a combined multidisciplinary approach to recurrent tumors of the scalp and calvarium. Intraoperatively, a fresh-tissue mapping modification of Mohs' histographic surgical technique is performed on the entire surgical specimen. This allows for total microscopic margin control of a recurrent basal cell carcinoma during a single surgical procedure. The resulting defect is immediately reconstructed by myocutaneous free flap transfer using microvascular techniques.

Adult↗