Biomedical subjects

C P Sayers

Publications and source records attributed to C P Sayers.

3 recordsLinked to original sources

PubMed1994

An operator interface for teleprogramming employing synthetic fixtures.

In the teleprogramming system an operator is presented with a virtual reality representation of a remote environment. The operator's interaction within that virtual environment is observed and translated into a sequence of robot program instructions for transmission to, and execution by, a robot at the remote site. In this paper we focus on operator interaction with the master station of the teleprogramming system. The use of synthetic fixtures to provide force and visual clues to assist the operator in performing tasks with speed and precision is discussed. It is suggested that, at least in some situations, it is both necessary and desirable to trade off realism for improved task performance. The difficulty of coping with exceptional conditions and, in particular, uncertainty in the world model used to generate the virtual environment is described and the operator interface for diagnosing and resolving errors is presented. An overview is also given of both the hardware and software used to implement master station for the teleprogramming system.

Computers↗

PubMed1976

Masson's "vegetant intravascular hemangioendothelioma:" a lesion often mistaken for angiosarcoma: study of seventeen cases located in the skin and soft tissues.

The occurrence of Masson's "hemangio-endotheliome vegetant intravasculaire" (Masson's pseudoangiosarcoma) in the skin and soft tissues is illustrated with 17 surgically excised specimens. Two forms are recognized; it may appear either as a pure lesion or as a focal condition in a pre-existing vascular process, such as pyogenic granuloma or hemangioma. The clinical appearance is not specific and the diagnosis can only be established by microscopic examination. It shows a predilection for the head and extremities. Its characteristic morphologic appearance makes possible its differentiation from a group of benign and malignant vascular proliferations. The key microscopic feature is the presence of a papillary growth composed of hyperplastic endothelial cells supported by delicate fibrous stalks entirely confined within the vascular lumen. The lesion should not be mistaken for angiosarcoma, since its clinical behavior is invariably benign.

Diagnosis, Differential↗

PubMed1975

Pulmonary elastic tissue in generalized elastolysis (cutis laxa) and Marfan's syndrome: a light and electron microscopic study.

We have studied elastic tissue changes in the lungs from patients with Marfan's syndrome, generalized elastolysis, patients with emphysema of other cause, and those dying from unrelated causes. Degenerative changes were seen in the elastic tissue fibers in patient's with Marfan's syndrome; they varied from mild to severe. Elastic fibers in the lungs of patients with cutis laxa showed by light and electron microscopy the same morphologic changes previously reported in the skin and vessels. While the alterations in individual elastic fibers in the alveolar septa appeared similar, in cutix laxa there was severe involvement of almost all fibers, whereas in Marfan's syndrome the involvement was not so severe, nor did it affect all fibers. On examination of lung sections from patients with cutis laxa or Marfan's syndrome, both were readily separable from normal and abnormal controls.

Adult↗