A critical evaluation of PEX

PEX, the PHIGS extension to the X Window System, is evaluated in the context of assumptions inherent in the PHIGS output, modeling, input, user interface, and system environment models. Problems not previously discussed arise when examining PEX this way. The problems not only pertain to the implementation of PEX, but also to implementing a 3-D library in a distributed windowing system in general. The University of Illinois PEX implementation serves as a reference to discuss the solutions proposed     

Should circulating anticoagulant [AKA anti-phospholipid] assays be a routine component of well-patient assessment?

Circulating anticoagulants are a major risk factor for thrombotic problems (eg, myocardial infarction, stroke) and pregnancy complications. The authors present a retrospective survey of anticardiolipin antibody and lupus anticoagulant in 200 consecutive patients presenting to their office.     

The Professional Workstation Research Project

Powerful, inexpensive processors, low-cost storage, and high-resolution color displays make single-user, networked, multiprogrammed computer workstations suitable replacements for the time-shared mainframe environment of the scientific and engineering professional. Distributed processing via networks of workstations connected to larger server machines, which are in turn connected to national and international networks, allows a completely new form of computer-aided organization for institutions. The flexibility and speed of such machines mean that a new revolution in information processing and human activity support is inevitable. The professional workstation project has as its immediate goal a networked, distributed system of single-user workstations. Each will use the Unix operating system and provide powerful object-oriented graphics tools that will enhance the productivity of scientific and engineering professionals.     

An Object-Oriented View of the User Interface

The object-oriented view of the user interface presented here is a model of object responsibilities-sharing and cooperation for a typical user interface. The model regards the user interface as a three-layer architecture, with the application contributing to one of the layers called the application exposure, The model seeks to promote user interface software reuse by coupling the user interface and the application with well-defined message protocols, by properly allocating user interfacefunctions to the layers so as to reduce and discipline their dependencies, and byfactoring complex abstractions into reusable secondary components.     

Client-server-based mobile robot control

A control architecture for an autonomous mobile robot usually consists of two components: (1) intelligent control software and (2) an operating system for resource access. From the point of view of a computer scientist, it is desirable to achieve a certain level abstraction from the resource (be it sensor or effector). Here, this is achieved by introducing a client-server framework for realizing abstract resource access and intelligent control. Hardware details are hidden in a middleware layer, which is inserted in between operating system and applications. In this paper, we present the most important features of our client-server approach. The servers decouple hardware and software dependencies. Communication is realized through the use of classes, offering a wide variety of client-server interaction. Event-driven servers and clients lead to quick responses in dynamic environments. Our approach gives reusability, portability, testability, and maintainability through data abstraction. It was successfully applied in our experimental platform ARS     

Combining Graphics and Windowing Standards in the XGKS System

In the past few years we have seen the acceptance of standards for both two and three dimensional computer graphics. Also during this time, the workstation community has converged on a common windowing system. This paper discusses the problems encountered in implementing graphics standards such as GKS and PHIGS PLUS within the X Window System environment.     

Application graphics modeling support through object orientation

The Graphical Application Modeling Support system (Grams), a three-dimensional graphics system that raises the abstraction level at which the application programmer and the end user interact with the system in the image-generation process, is described. The application, graphics and rendering layers of Grams and its organization of class hierarchies are discussed. An application of the Grams system is presented     

Activation of rat hepatic stellate cells in culture is associated with increased sensitivity to endothelin 1

The effect of endothelin (ET) 1 on intracellular Ca2+ transients in cultured rat hepatic stellate cells (HSCs) during transformation was studied by use of single-cell fluorescence. Regardless of the duration of HSC culture, ET-1 caused a BQ-123-sensitive but IRL-1038-insensitive elevation of [Ca2+]i, indicating the involvement of ETA but not ETB receptors. HSCs in early culture ("quiescent HSCs") were mildly responsive to ET-1: the ET-1 concentration required to obtain a [Ca2+]i transient in 50% of the cells (RC50) was 7 nmol/L, and all cells responded to ET-1 concentrations above 40 nmol/L. With culture time, -smooth muscle actin (-SMA) expression increased, as did the ET-1 sensitivity of cells, resulting in a shift of the RC50 value from 7 nmol/L to 13 pmol/L within 8 days. Independent of the duration of culture, ET-1 sensitivity was higher in -SMA-expressing cells. On the other hand, sensitivity of HSCs to produce a [Ca2+]i response to extracellular uridin 5'-triphosphate (UTP) or phenylephrine did not change during the activation process. There was no difference between quiescent and activated HSCs with respect to the sharing of intracellular Ca2+ stores, which could be mobilized by ET-1, UTP, and phenylephrine, respectively. The data suggest three conclusions. (1) A marked increase in ET-1 sensitivity of HSCs during the activation process suggests a potentiation of autocrine/paracrine stimulation. (2) HSCs are susceptible to -adrenergic and purinergic stimulation, but sensitivity to phenylephrine and UTP is not affected during the transformation process. (3) The ET-1-mobilizable Ca2+ store is contained in and is smaller than the Ca2+ pool, which is mobilized by phenylephrine or UTP.     

The relationship of the dimer content of rosin determined by gas chromatography to crystallization time

The resin acid dimer content of rosin influences the crystallization time, as determined with the Burrell-Castor Gelometer. A gas chromatographic packing prepared by treatment of Chromosorb W with dimethyldichlorosilane and trimethylchlorosilane resolved the methyl esters of rosin dimers into 15 components. A vacuum stripping method for assay of rosin dimer agrees with results obtained by quantitative gas chromatography.     

Tracing rays with the area sampling machine

The area sampling buffer concept unifies the three types of sampling functionalities (pixel-area sampling, secondary direction sampling, and light-source area sampling) of a ray tracer with the scan-conversion process. The Area Sampling Machine is a parallel computing system with custom processing units designed to take advantage of these merged properties. This paper age of these merged properties. This paper first describes the architecture of the Area Sampling Machine and then present our simulation results. A successful implementation of the Area Sampling Machine would speed up ray-tracing style image generation processes with the mature hardware technology of Z-buffer scan conversion.