Biomedical subjects
Publications and source records attributed to W Pieper.
In comparison to pancreatic cancer, extrahepatic cholangiocarcinoma has a better prognosis and a higher resection rate, but it is tainted with the occurrence of metachronic tumors. Metachronic tumors of the female genitalia are described in the literature, but metachronic gastric cancer after curative treatment of cholangiocacinoma is also possible.
The dielectric properties of suspensions of spherical polystyrene particles with radii of 34 and 50 nm, in aqueous electrolyte solutions were measured in the frequency range of 10 kHz to 30 GHz using HP 4192A impedance and 8753A network analyzers, and double path interferometers. The samples were prepared from the stock suspensions with a high particle concentration (volume fraction of 0.4), which were used either unchanged or diluted with increasing amounts of water down to a concentration of 0.05. The permittivity and total loss spectra showed three well-defined relaxation regions, which could successfully be interpreted using an existing model [Grosse, C., J. Phys. Chem. 92, 3905 (1988)] (corrected by including a term of counterion diffusion on the particle surface). A model spectral function was fitted to the data using seven free parameters: the static conductivity of the electrolyte solution, three parameters associated with the relaxation of the electrolyte solution, and just three parameters for the description of both the counterion and the Maxwell-Wagner relaxations. For different particle concentrations, the values of the surface conductivity (obtained from the Maxwell-Wagner parameters) remained essentially constant, while the low-frequency relaxation parameters exhibited very good agreement with theoretical predictions in Delgado, A. V., Arroyo, F. J., Gonzales-Caballero, F., Shilov, V. N., and Borkovskaya, Yu. B., Colloids Surf. A, in press. Copyright 1998 Academic Press.
In two experiments we studied the influence of dexterity (controls, typists, pianists) and of differences between the five fingers of the dominant hand on speed and accuracy in a 5-choice reaction task. We used five coloured squares (Blue, Green, Yellow, Red, White) as stimuli, randomly varying foreperiods (3-10s) and an intermediate stimulus-response-compatibility. The results reported here were independent of sex, foreperiods, and colour of stimuli. In Experiment 1 (N = 168) with three groups (controls, typists, pianists) thumb and little finger showed significantly shorter reaction times than did index, middle, and ring finger. This difference did not interact with dexterity. Averaged across all the fingers typists and controls did not differ. Pianists showed significantly shorter reaction times than these two groups. Experiment 2 (N = 40) replicated all these findings. In both experiments groups did not differ in speed-accuracy-trade-off. The accuracy of the fingers was independent of dexterity. In all three groups the little finger showed the lowest rate of false alarms and the highest degree of reliability. The frequency distribution of finger confusions in all groups was in accordance with the spatial proximity of fingers: the closer their proximity the higher were the rates of confusion. In addition, these distributions showed an asymmetry across all three groups. The finger next to the 'correct' finger in direction towards the thumb showed the highest false alarm rate in each case.
To test the functional capacity of a finger, the documentation of its range of motion is of great importance. The capacity to grasp is determined by the flexion and extension ability of the finger joints. Dexterity is based on the mobility field of the finger end, within the grasping area. Both can be shown graphically. A table is described with which the mobility within the grasping area of each finger can be tested and documented without joint measuring. The advantage of this method is the easy handling and the graphic demonstration, allowing a very precise judgment of the functional capacity of a finger. The graphic demonstration is especially qualified for testing disabled fingers as well as showing progress during physiotherapy.
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Twenty-four university students received differential Pavlovian conditioning with two colored stimuli separately accompanied by shock, and two other colored stimuli separately presented without shock. The reinforced and nonreinforced pairs of stimuli both contained complementary elements. After differentiation between the reinforced and nonreinforced elements was established, the complementary pairs were each additively mixed, (i.e., presented at the same time and in the same locus), producing two identical white compounds (established by pilot study). The subjects' skin-conductance responses to the two compounds showed that their different conditioning histories did not result in different responses. Rather, a simple declining function was obtained, resembling habituation or extinction. It was concluded that the definition of the conditional stimulus as a physical event is inappropriate in studies in which physically different stimuli may result in identical internal processes (or phenomenologic experiences)--for example, in additive color mixture.