ERP correlates of word production before and after stroke in an aphasic patient

No abstract available

Fabrication of optical planar waveguides in KY(WO4)2KY(WO_4)_2 by He-ion implantation

In this paper, planar waveguides produced by He-ion implantation have been demonstrated in undoped and Yb-doped KY(WO/sub 4/)/sub 2/ crystals. The effective refractive indices of guided modes in surface planar waveguides were measured by dark m-line spectroscopy and the refractive index profiles were reconstructed by calculations based on the inverse WKB method. The end-faces of implanted crystals were polished and the waveguiding properties of the obtained planar structures were investigated using a laser diode at 980 nm and a CCD camera

A clinical evaluation of the hydron toric and bausch and lomb toric self contact lenses

A clinical evaluation of two currently available toric hydrogel lens was made. The Hydron Tor ic and the Bausch and lomb Toric lenses are both front surface torics with prism ball aststahilization features. The Hydron lens also employs an inferior truncation and an aspheric back surface. First fit success rate for the Hydron lenses on 27 eyes was 40%. An increase to 72% success was achieved after one lens reorder and 76% were fit after a total of two reorders. Len::es had been worn for periods ranging from one week to six months. Of 27 eyes fit with the Bausch and Lomb lens, 71% were still wearing the initial lens fit after one to four weeks. Further data on these lenses i s forthcoming in Part II of this study. Physiological difficulties with the Hyd.rons were the primary reasons for failures, this resulted in l ens reorders, most frequently due to lens tightening, or to edema caused by the thick lenses. Stabilization was excellent for all types and magnitudes of astigmatism in the study. Bausch & Lomb offers limited parameters and some stabilization difficulties were encountered with all types of astigmatism but more frequently with against the rule types

17-jähriger Mann mit akuten Bauchschmerzen, Hämatochezie und Exanthem

Zusammenfassung: Ein 17-jähriger Patient stellte sich mit kolikartigen abdominellen Schmerzen und Diarrhö vor. Als weitere Symptome traten Petechien, Arthralgien und eine Hämatochezie auf. Sonographisch bestand eine auffällige Ileozökalregion. Endoskopisch fand sich eine Ileitis terminalis, und histologisch zeigte sich hier eine leukozytoklastische Vaskulitis mit IgA-Ablagerungen. Die Kasuistik zeigt exemplarisch die mehrzeitige klinische Manifestation der Purpura Schönlein-Henoch und deren Verlau

Fabrication of optical planar and channel waveguides in Yb³⁺ doped KY(WO₄)₂ by He-ion implantation

Light ion implantation can be regarded as a universal tool for fabricating low-loss waveguide structures in optically active oxide materials. We have fabricated planar optical waveguides in $KY(WO_4)_2$:(2%)$Yb^{3+}$ crystals by implanting He+ ions at 1.5 MeV, with doses ranging from 1 to 3x10^16 ions/cm2. An optical barrier with a decreased effective refractive index was created at the end of the ions' tracks, situated approximately 3.5 μm below the surface. The change in refractive index with respect to the bulk value and its stability to thermal treatment were investigated by dark m-line spectroscopy. Surface channel waveguides were obtained by writing sidewalls into the planar guiding layer by implantation through a slit. The sidewalls were produced by keeping the ion energy fixed and varying the incident angle of implantation. Channel waveguides of 5-μm width and 4-μm depth were obtained in the regions between the implanted sidewalls. Beam-propagation parameters were measured by investigating the output profile of end-coupled, fundamental-mode laser light at 980 nm. The results of loss measurements will be presented at the conference

Human Processing of Behaviorally Relevant and Irrelevant Absence of Expected Rewards: A High-Resolution ERP Study

Acute lesions of the posterior medial orbitofrontal cortex (OFC) in humans may induce a state of reality confusion marked by confabulation, disorientation, and currently inappropriate actions. This clinical state is strongly associated with an inability to abandon previously valid anticipations, that is, extinction capacity. In healthy subjects, the filtering of memories according to their relation with ongoing reality is associated with activity in posterior medial OFC (area 13) and electrophysiologically expressed at 220–300 ms. These observations indicate that the human OFC also functions as a generic reality monitoring system. For this function, it is presumably more important for the OFC to evaluate the current behavioral appropriateness of anticipations rather than their hedonic value. In the present study, we put this hypothesis to the test. Participants performed a reversal learning task with intermittent absence of reward delivery. High-density evoked potential analysis showed that the omission of expected reward induced a specific electrocortical response in trials signaling the necessity to abandon the hitherto reward predicting choice, but not when omission of reward had no such connotation. This processing difference occurred at 200–300 ms. Source estimation using inverse solution analysis indicated that it emanated from the posterior medial OFC. We suggest that the human brain uses this signal from the OFC to keep thought and behavior in phase with reality