MEG and EEG Dipole Clusters from Extended Cortical Sources

Manfred Fuchs,Jo¨rn Kastner,Reyko Tech,Michael Wagner,Fernando Gasca 대한의용생체공학회 2017 Biomedical Engineering Letters (BMEL) Vol.7 No.3

Data from magnetoencephalography (MEG) andelectroencephalography (EEG) suffer from a rather limitedsignal-to-noise-ratio (SNR) due to cortical backgroundactivities and other artifacts. In order to study the effect ofthe SNR on the size and distribution of dipole clustersreconstructed from interictal epileptic spikes, we performedsimulations using realistically shaped volumeconductor models and extended cortical sources with differentsensor configurations. Head models and corticalsurfaces were derived from an averaged magnetic resonanceimage dataset (Montreal Neurological Institute). Extended sources were simulated by spherical patches withGaussian current distributions on the folded cortical surface. Different patch sizes were used to investigate cancellationeffects from opposing walls of sulcal foldings andto estimate corresponding changes in MEG and EEG sensitivitydistributions. Finally, white noise was added to thesimulated fields and equivalent current dipole reconstructionswere performed to determine size and shape of theresulting dipole clusters. Neuronal currents are orientedperpendicular to the local cortical surface and show cancellationeffects of source components on opposing sulcalwalls. Since these mostly tangential aspects from largecortical patches cancel out, large extended sources exhibitmore radial components in the head geometry. This effecthas a larger impact on MEG data as compared to EEG,because in a spherical head model radial currents do notyield any magnetic field. Confidence volumes of singlereconstructed dipoles from simulated data at differentSNRs show a good correlation with the extension ofclusters from repeated dipole reconstructions. Size andshape of dipole clusters reconstructed from extended corticalsources do not only depend on spike and timepointselection, but also strongly on the SNR of the measuredinterictal MEG or EEG data. In a linear approximation thesize of the clusters is proportional to the inverse SNR.

Looking into an Austrian mother company and their Korean subsidiary based on their Internationalization Process and Knowledge Management Strategy: Case Study based on Anton Paar

Sonya-Rachel Gharibeh,Manfred Fuchs,Sangwook Kim 한국경영정보학회 2018 한국경영정보학회 학술대회논문집 Vol.2018 No.5

When we think about the economy of the 21st century, globalization and multinational enterprises (MNEs) cannot be ignored. Therefore, my Master Thesis is going to look into Anton Paar, a multinational company that is based both in Austria and South Korea, in this case the mother company is based in Graz Austria and their South Korean subsidiary is based in Seoul. When thinking about an MNE the first step of the company is the internationalization process, the journey of coming to the South Korean market. The obstacles that had to be overcome where in the field of law, language, culture and many more. After looking at the internationalization process that was concerned with external factors, an MNE must turn to some of their internal factors. One of the most important internal factors in a globalized economy is knowledge management. Knowledge management of a MNE must figure out how they will transfer their knowledge from the mother company to their subsidiary, how and if they should adapt their original strategy or use some of the knowledge they gain from the subsidiary in different fields of their mother company and other subsidiaries. Another big concern is the management of knowledge loss and what they will do to enforce their employees to share and transcribe their knowledge. These questions and many more are of utmost importance when it comes to an MNE and their way of working in a globalized economy. In my Master Thesis I will try to answer these questions for the company Anton Paar, via semi structured interviews and an intensive literature review.

Statistical Non-Parametric Mapping in Sensor Space

Michael Wagner,Reyko Tech,Manfred Fuchs,Jo¨rn Kastner,Fernando Gasca 대한의용생체공학회 2017 Biomedical Engineering Letters (BMEL) Vol.7 No.3

Establishing the significance of observed effectsis a preliminary requirement for any meaningful interpretationof clinical and experimental Electroencephalographyor Magnetoencephalography (MEG) data. We propose amethod to evaluate significance on the level of sensorswhilst retaining full temporal or spectral resolution. Inputdata are multiple realizations of sensor data. In this context,multiple realizations may be the individual epochs obtainedin an evoked-response experiment, or group study data,possibly averaged within subject and event type, or spontaneousevents such as spikes of different types. In thiscontribution, we apply Statistical non-Parametric Mapping(SnPM) to MEG sensor data. SnPM is a non-parametricpermutation or randomization test that is assumption-freeregarding distributional properties of the underlying data. The method, referred to as Maps SnPM, is demonstratedusing MEG data from an auditory mismatch negativityparadigm with one frequent and two rare stimuli and validatedby comparison with Topographic Analysis of Variance(TANOVA). The result is a time- or frequencyresolvedbreakdown of sensors that show consistentactivity within and/or differ significantly between event orspike types. TANOVA and Maps SnPM were applied tothe individual epochs obtained in an evoked-responseexperiment. The TANOVA analysis established dataplausibility and identified latencies-of-interest for furtheranalysis. Maps SnPM, in addition to the above, identifiedsensors of significantly different activity between stimulustypes.

Five-fold Gastrointestinal Electrical Stimulation With Electromyography-based Activity Analysis: Towards Multilocular Theranostic Intestinal Implants

Jonas F Schiemer,Axel Heimann,Karin H Somerlik-Fuchs,Roman Ruff,Klaus-Peter Hoffmann,Jan Baumgart,Manfred Berres,Hauke Lang,Werner Kneist 대한소화기 기능성질환∙운동학회 2019 Journal of Neurogastroenterology and Motility (JNM Vol.25 No.3

Background/AimsMotility disorders are common and may affect the entire gastrointestinal (GI) tract but current treatment is limited. Multilocularsensing of GI electrical activity and variable electrical stimulation (ES) is a promising option. The aim of our study is to investigate theeffects of adjustable ES on poststimulatory spike activities in 5 GI segments. MethodsSix acute porcine experiments were performed with direct ES by 4 ES parameter sets (30 seconds, 25 mA, 500 microseconds or1000 microseconds, 30 Hz or 130 Hz) applied through subserosal electrodes in the stomach, duodenum, ileum, jejunum, and colon. Multi-channel electromyography of baseline and post-stimulatory GI electrical activity were recorded for 3 minutes with hook needleand hook-wire electrodes. Spike activities were algorithmically calculated, visualized in a heat map, and tested for significance byPoisson analysis. ResultsPost-stimulatory spike activities were markedly increased in the stomach (7 of 24 test results), duodenum (8 of 24), jejunum (23 of24), ileum (18 of 24), and colon (5 of 24). ES parameter analysis revealed that 80.0% of the GI parts (all but duodenum) required apulse width of 1000 microseconds, and 60.0% (all but jejunum and colon) required 130 Hz frequency for maximum spike activity. Fivereaction patterns were distinguished, with 30.0% earlier responses (type I), 42.5% later or mixed type responses (type II, III, and X),and 27.5% non-significant responses (type 0). ConclusionsMultilocular ES with variable ES parameters is feasible and may significantly modulate GI electrical activity. Automatedelectromyography analysis revealed complex reaction patterns in the 5 examined GI segments.

ROS-induced ATF3 causes susceptibility to secondary infections during sepsis-associated immunosuppression

Hoetzenecker, Wolfram,Echtenacher, Bernd,Guenova, Emmanuella,Hoetzenecker, Konrad,Woelbing, Florian,Br체ck, J체rgen,Teske, Anna,Valtcheva, Nadejda,Fuchs, Kerstin,Kneilling, Manfred,Park, Ji-Hyeon,Kim, K Nature Publishing Group, a division of Macmillan P 2012 Nature medicine Vol.18 No.1

Sepsis, sepsis-induced hyperinflammation and subsequent sepsis-associated immunosuppression (SAIS) are important causes of death. Here we show in humans that the loss of the major reactive oxygen species (ROS) scavenger, glutathione (GSH), during SAIS directly correlates with an increase in the expression of activating transcription factor 3 (ATF3). In endotoxin-stimulated monocytes, ROS stress strongly superinduced NF-E2??related factor 2 (NRF2)??dependent ATF3. In vivo, this ROS-mediated superinduction of ATF3 protected against endotoxic shock by inhibiting innate cytokines, as Atf3<SUP>??/??</SUP> mice remained susceptible to endotoxic shock even under conditions of ROS stress. Although it protected against endotoxic shock, this ROS-mediated superinduction of ATF3 caused high susceptibility to bacterial and fungal infections through the suppression of interleukin 6 (IL-6). As a result, Atf3<SUP>??/??</SUP> mice were protected against bacterial and fungal infections, even under conditions of ROS stress, whereas Atf3<SUP>??/??</SUP>Il6<SUP>??/??</SUP> mice were highly susceptible to these infections. Moreover, in a model of SAIS, secondary infections caused considerably less mortality in Atf3<SUP>??/??</SUP> mice than in wild-type mice, indicating that ROS-induced ATF3 crucially determines susceptibility to secondary infections during SAIS.