A selective Pt-CdS photodiode to monitor erythemal flux.

The design and potential benefit of a solar ultraviolet (UV) radiometer reporting a maximum instantaneous flux of erythemally weighted heterogeneous energy is considered. The proposed device is electronically peak detecting; the user would ideally 'point and paint' the sun to find a localized maximum. A projected exposure time can be calculated from an instantaneous reading of erythemally weighted flux for a given minimal erythemal dose (MED) specified by the user. This calculation, though not necessarily providing a true exposure time, may be useful and informative in that it serves as a more 'recognizable' measure of erythemal flux and introduces a custom scale for each individual via their MED. Erythemal flux is calculated as the weighted integral sum [symbol: see text]j(lambda,t) epsilon(lambda) d lambda, where j (lambda, t) is the instantaneous angular integrated spectral irradiance accepted by human skin. This instrument proposal uses a single interference filter over a Pt-CdS photodiode; the interference filter is offered as a nominal design transmittance. The simulated response of the selective photodiode has a near-linear relation to the effective irradiance. Test inputs for evaluation purposes and to elucidate a transducer response are constructed from a spline interpolation of the World Radiation Center (WRC) spectrum and classic transmittance models. Our desired erythemal flux is offered in interconvertible UV Indexes (UVIs) as a function of zenith angle and atmosphere, characterized by elevation, ozone path, and turbidity.

Tissue architectural features for the grading of prostatic carcinoma.

In research for the development of a computer-aided workstation for the objective grading of prostatic carcinoma, tissue architectural (histometric) features were analyzed in ten cases each of well-differentiated, moderately differentiated and poorly differentiated carcinoma (as subjectively graded by the consensus of a panel of experts). Sections were cut at 4 microns, stained by the Feulgen reaction and digitized by two different video-based photometric systems. Some images were interactively segmented, considering the histometric clues to be studied; others were automatically segmented by an expert system-guided technique. The latter procedure produced good results, with over 90% of the nuclei judged to be correctly segmented in 64% of the fields studied and over 80% in another 24% of the fields. While the number of nuclei per field provided some separation of well-differentiated from other lesions, the number of nuclei per gland distinguished between well-differentiated and moderately differentiated lesions. Simplicial decomposition of the images also provided a measure of the degree of differentiation, as did the "texture" of the nuclear placement, based on two run-length statistics. Combination of the run-length features distinguished the three categories of lesions with statistical significance. The results of this study provided insights into the problems (such as the effect of field boundaries) faced in the design of an computer-aided grading system. They also showed the value of expert system-guided scene segmentation and of such histometric features as the field cellularity and the number of nuclei per gland for the discrimination between lesions of different grades of differentiation.

Transdiaphragmatic approach to thoracic duct ligation in the cat.

An approach combining ventral midline celiotomy with transdiaphragmatic thoracotomy was evaluated in eight healthy cats for ligation of the thoracic duct system. Evans Blue solution was injected into the right colic lymph node to outline the intestinal lymphatic trunk and the thoracic duct system. Three cats (group 1) had mesenteric lymphangiograms and three (group 2) had only lymph node dye injection before thoracic duct ligation. The thoracic duct system was ligated with hemostatic clips just cranial to the aortic hiatus of the diaphragm, through a left transdiaphragmatic thoracotomy. Two cats (group 3) had prethoracotomy mesenteric lymphangiograms and thoracic duct isolation without ligation. Mesenteric lymphangiography was performed immediately after the surgery. In all of the cats, an absence of contrast medium in the thoracic duct system cranial to the surgical site was interpreted as complete obstruction. Four weeks after ligation, there was complete obstruction of the thoracic duct system with alternate lymphaticovenous communications in four of the six cats with ligated thoracic duct systems. Partial obstruction of the thoracic duct system with alternate lymphaticovenous communications was present in the other two cats. Both cats without thoracic duct ligation had patent thoracic duct systems. At necropsy of the six cats with ligated thoracic ducts, there was mild focal lymphadenitis of injected lymph nodes in three cats. The wall of the aorta adjacent to the hemostatic clips was normal in all six cats. The surgical technique was simple and provided excellent exposure. Vital staining with Evans Blue helped visualize the thoracic duct system, but mesenteric lymphangiography did not. Postligation lymphangiography was not of value in identifying incomplete ligation.

Patient classification based on cytologic sample profiles. I. Basic measures for profile construction.

Past efforts in the field of automated cell recognition have focused upon the separation and classification of cell types. From these efforts, large data banks have been built and work in the field is now shifting towards the practical application of this information for clinical diagnoses. This paper presents the initial results of work on a system developed to undertake the reduction of the masses of data into diagnostically useful patient cytologic sample profiles.

Assessing the potential of change in institutions.

The present article discusses the importance of evaluating the strengths and weaknesses of key institutional personnel prior to attempting program innovations. The importance of such individuals in "making" or "breaking" effective programs is emphasized, and various key hospital staff members are described. A simple evaluation process is discussed with the purpose of better anticipating problem areas in program development. It was concluded that in some cases, project implementations should not be attempted when assessed personnel problems appear capable of seriously limiting the effectiveness of a program.

Semantic processing and organization in free recall.

It was hypothesized that both semantic processing and organizational activity are necessary for optimal free recall performance. In a series of three experiments, subjects were presented with a list of randomly selected nouns and were asked to make up a meaningful sentence for each noun. The subjects also rated the difficulty of using each noun. The subjects were instructed to try to remember words that were labeled "remember" words. For words that were labeled "story" words, the subjects were instructed only to make each sentence, using the word, part of an ongoing story which each subject was to make up. A test of retention for all presented words, using retention intervals of both 1 min and 24 h, showed that the story words were always recalled better than were the remember words. However, the amount of sequential organization was the same for both the story and the remember words. Recognition performance was found to be the same for both types of words. In addition, the story words were rated as being more difficult than the remember words. It was concluded that extensive semantic processing without organization is not sufficient for optimal recall.