Improving zero-training brain-computer interfaces by mixing model estimators

Verhoeven, T,Hü,bner, D,Tangermann, M,Mü,ller, K R,Dambre, J,Kindermans, P J IOP 2017 Journal of neural engineering Vol.14 No.3

<P> <I>Objective</I>. Brain-computer interfaces (BCI) based on event-related potentials (ERP) incorporate a decoder to classify recorded brain signals and subsequently select a control signal that drives a computer application. Standard supervised BCI decoders require a tedious calibration procedure prior to every session. Several unsupervised classification methods have been proposed that tune the decoder during actual use and as such omit this calibration. Each of these methods has its own strengths and weaknesses. Our aim is to improve overall accuracy of ERP-based BCIs without calibration. <I>Approach</I>. We consider two approaches for unsupervised classification of ERP signals. Learning from label proportions (LLP) was recently shown to be guaranteed to converge to a supervised decoder when enough data is available. In contrast, the formerly proposed expectation maximization (EM) based decoding for ERP–BCI does not have this guarantee. However, while this decoder has high variance due to random initialization of its parameters, it obtains a higher accuracy faster than LLP when the initialization is good. We introduce a method to optimally combine these two unsupervised decoding methods, letting one method’s strengths compensate for the weaknesses of the other and vice versa. The new method is compared to the aforementioned methods in a resimulation of an experiment with a visual speller. <I>Main results</I>. Analysis of the experimental results shows that the new method exceeds the performance of the previous unsupervised classification approaches in terms of ERP classification accuracy and symbol selection accuracy during the spelling experiment. Furthermore, the method shows less dependency on random initialization of model parameters and is consequently more reliable. <I>Significance</I>. Improving the accuracy and subsequent reliability of calibrationless BCIs makes these systems more appealing for frequent use.</P>

Thermal emergence of laser-induced spin dynamics for a Ni4 cluster

Sold, S.,Lefkidis, G.,Kamble, B.,Berakdar, J.,Hü,bner, W. American Physical Society 2018 Physical Review B Vol.97 No.18

<P>We investigate the thermodynamic behavior of laser-induced spin dynamics of a perfect and a distorted Ni-4 square in combination with an external thermal bath, by using the Lindblad-superoperator formalism. The energies of the planar molecules are determined with highly correlated ab initio quantum-chemistry calculations. When the distorted structure couples to the thermal bath a unique spin dynamics, i.e., a spin flip, emerges, due to the interplay of optically and thermally induced electronic transitions. The charge and spin relaxation times in dependence on the coupling strength and the bath temperature are determined and compared.</P>

Human primordial germ cell commitment <i>in vitro</i> associates with a unique PRDM14 expression profile

Sugawa, Fumihiro,Araú,zo-Bravo, Marcos J,Yoon, Juyong,Kim, Kee-Pyo,Aramaki, Shinya,Wu, Guangming,Stehling, Martin,Psathaki, Olympia E,Hü,bner, Karin,Schö,ler, Hans R BlackWell Publishing Ltd 2015 The EMBO journal Vol.34 No.8

<P>Primordial germ cells (PGCs) develop only into sperm and oocytes <I>in vivo</I>. The molecular mechanisms underlying human PGC specification are poorly understood due to inaccessibility of cell materials and lack of <I>in vitro</I> models for tracking the earliest stages of germ cell development. Here, we describe a defined and stepwise differentiation system for inducing pre-migratory PGC-like cells (PGCLCs) from human pluripotent stem cells (PSCs). In response to cytokines, PSCs differentiate first into a heterogeneous mesoderm-like cell population and then into PGCLCs, which exhibit minimal PRDM14 expression. PGC specification in humans is similar to the murine process, with the sequential activation of mesodermal and PGC genes, and the suppression of neural induction and of <I>de novo</I> DNA methylation, suggesting that human PGC formation is induced via epigenesis, the process of germ cell specification via inductive signals from surrounding somatic cells. This study demonstrates that PGC commitment in humans shares key features with that of the mouse, but also highlights key differences, including transcriptional regulation during the early stage of human PGC development (3–6 weeks). A more comprehensive understanding of human germ cell development may lead to methodology for successfully generating PSC-derived gametes for reproductive medicine.</P>

Mathematics as Motive, Means and Method in Art : An Example

Corinna Gröbner 한국미술이론학회 2014 미술이론과 현장 Vol.0 No.18

저자는 자신의 작업을 중심으로 수학과 미술의 연결고리, 즉 정상분배의 수행성을 탐구하는 수단으로서 수학적 모델의 원리를 고찰한다. 본 논문은 자신의 작업과 제작과정 에 대한 기술과 작업과 제작과정 모두에 작용하는 수학적 측면에 대한 분석으로 구성되어 있다. 분석의 부분은 작가 자신과 가상의 질의자 간의 문답 형식으로 제시되고, 작가의 동기와 수학이 작업과정에 작용하는 상이한 면들을 포괄하여 진행된다. 행위자 연결망 이론가인 미셀 칼론의 이론에 따라 제작과정은 ‘번역’의 연쇄망으로 기술될 것이며, 예술작품이 점점 수학적 공식의 대변인이 되지만 결국 전복하는 과정을 보여준다. 이 분석 부분은 수학을 사용하는 작가들의 간략한 토론으로 마무리된다. The paper at hand reflects on the intertwinement of mathematics and art using the example of the author’s art project: a meditation on the principle of mathematical modeling by means of exploring the performativity of the normal distribution. The article comprises of a description of the artworks, an account of their manufacturing process and an analysis of the mathematical aspects in both the artworks themselves and their genesis. The analysis part is presented in form of a dialogue between a fictitious questioner and the artist. It embraces the artist’s motives and the different levels on which mathematics comes into play. Referring to actor-network-theorist Michel Callon the production process will be delineated as a chain of “translations” where the artwork by and by becomes the “spokesman” of a mathematical formula, however, in the end commits treason. The analysis part is rounded out with a brief discussion of artists that employ mathematics.

Predicting Proximal Junctional Kyphosis After Adult Spinal Deformity Surgery: A Step Towards True “Precision” Medicine?: Commentary on “Development and Validation of an Online Calculator to Predict Proximal Junctional Kyphosis After Adult Spinal

Lara M. Höbner,Alexandra Grob,Victor E. Staartjes 대한척추신경외과학회 2023 Neurospine Vol.20 No.4

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A Compartmented Microfluidic Reactor for Protein Modification Via Solid-phase Reactions - Semi-automated Examination of Two PEGylation Routes

Regina Fraas,Jonas Ferdinand Hübner,Juliane Diehm,Ramona Faas,Rudolf Hausmann,Matthias Franzreb 한국생물공학회 2019 Biotechnology and Bioprocess Engineering Vol.24 No.2

Microfluidics has emerged as a relatively new scientific field enabling fast reaction times and low demands for reactants. Pursuing these advantages, a compartmented, microfluidic reactor was developed in our group which is suitable for the semi-automated processing of complex reaction cascades including solid phases. As one of the first application examples, we analyzed the influence of different reaction paths on the modification of a model protein in a solid-phase reaction. Extensive characterization experiments were performed: Amongst others, an organic phase was identified which is immiscible with water and compatible with the designated PEGylation reactions. Such organic solvents function as separation plugs for different water based reaction plugs within the microfluidic system. Mixing within the microfluidic system was investigated, in order to ensure an efficient solid-phase reaction. Subsequently, solid-phase PEGylation of the target protein was performed within the microfluidic system via two different reaction cascades. The longest reaction cascades comprised all reactions from particle activation, via protein immobilization and PEGylation to elution and consisted of seven steps. PEGylation in the reactor took place with comparable yields and results as in the control reaction outside the reactor. Due to the modularity, the presented reactor proves to be a versatile instrument for semi-automated reactions and parameter screening, being compatible with biological systems. It combines the advantages of closed channel systems like lab on a chip microfluidics with the flexibility and preparative scale sample volume of larger liquid handling stations.

Myrciaria dubia Juice (camu-camu) Exhibits Analgesic and Antiedematogenic Activities in Mice

Francisco Carlos da Silva,Alessandra Hübner de Souza,Bruna Kempfer Bassoli,Gleiciane Alves Prates,Cíntia Daudt,Dionatas Ulises de Oliveira Meneguetti,Áurea Pandolfo Corrêa,Iasmine Berbigier de Oliveir 한국식품영양과학회 2021 Journal of medicinal food Vol.24 No.6

The Myrciaria dubia (Myrtaceae) fruit is traditionally used to treat malnutrition due to its high levels of vitamin C and phenolic compounds. Because of its composition, this plant is very promising in the research of novel natural treatment for pain disorders. This study analyzed the phytochemical profile of M. dubia juice and assessed its antinociceptive and antiedematogenic potential. The phytochemical profile was determined through high-performance liquid chromatography (HPLC), the oral antinociceptive effect of M. dubia 50% juice (Md50) was evaluated by formalin, hot plate and Complete Freund's Adjuvant tests and the antiedematogenic activity by paw edema. HPLC revealed the presence of ascorbic acid, rutin, and ellagic acid as major compounds. Md50 showed an antinociceptive effect in the acute and chronic phases of the formalin test. In the hot plate test, Md50 also induced an antinociceptive effect of 0.5 up to 6 h, showing antinociceptive and antiedematogenic potential without changing the spontaneous locomotion of animals. All protocols were submitted and approved by the Ethics Committee for use of Animals of the Lutheran University of Brazil (protocol No. 2013-30P).

Skin Protection Seminars to Prevent Occupational Skin Diseases: Results of a Prospective Longitudinal Study in Apprentices of High-risk Professions

Annika Wilke,Richard Brans,Kathrin Nordheider,Antje Braumann,Anja Hübner,Flora K. Sonsmann,Swen M. John,Britta Wulfhorst 한국산업안전보건공단 산업안전보건연구원 2018 Safety and health at work Vol.9 No.4

Background: Occupational skin diseases (OSDs) are frequent in professions with exposure to skin hazards. Thus, a health educational intervention for apprentices of high-risk professions was conducted. It was the aim of this study to gain insight into possible effects of this intervention. Methods: A one-time skin protection seminar was conducted in 140 apprentices of health-related and non-healtherelated professions [trained cohort (TC)]. In addition, 134 apprentices of the same occupations were monitored [untrained cohort (UTC)]. The OSD-specific knowledge and the skin condition of the hands were assessed at baseline (T0), after the seminar (T1), and after 6 (T2) and 12 months (T3). Results: The OSD-specific knowledge increased in all cohorts from T0 to T3, but we found a significantly higher knowledge in the TC at T2 (p < 0.001, t = 3.6, df = 196, 95% confidence interval ¼ 0.9, 3.3) and T3 (p < 0.001, t = 3.8, df = 196, 95% confidence interval = 1.0, 3.2) compared to the UTC. Our results indicated a better skin condition of the hands in the TC of the health-related professions but not in the non-healtherelated professions. Conclusion: The study indicates that an educational intervention may positively influence the diseasespecific knowledge and the prevalence of OSD in apprentices. However, definite conclusions cannot be drawn because of the heterogeneous study cohorts and the study design. Future research should aim at tailoring primary prevention to specific target groups, e.g., in view of the duration and frequency of skin protection education, different professions, and gender-specific prevention approaches.

Targeting Moderate and Severe Male Stress Urinary Incontinence With Adjustable Male Slings and the Perineal Artificial Urinary Sphincter: Focus on Perioperative Complications and Device Explantations

Alexander Kretschmer,Tanja Hüsch,Frauke Thomsen,Dominik Kronlachner,Alice Obaje,Ralf Anding,Tobias Pottek,Achim Rose,Roberto Olianas,Alexander Friedl,Wilhelm Hübner,Roland Homberg,Jesco Pfitzenmaier,F 대한배뇨장애요실금학회 2017 International Neurourology Journal Vol.21 No.2

Purpose: To analyze perioperative complications and postoperative explantation rates for selected readjustable male sling systems and the perineal single-cuff artificial urinary sphincter (AUS) in a large, contemporary, multi-institutional patient cohort. Methods: Two hundred eighty-two male patients who underwent implantation between 2010 and 2012 in 13 participating institutions were included in the study (n=127 adjustable male sling [n=95 Argus classic, n=32 Argus T], n=155 AUS). Perioperative characteristics and postoperative complications were analyzed. The explantation rates of the respective devices were assessed using the Fisher exact test and the Mann-Whitney U-test. A Kaplan-Meier curve was generated. Potential features associated with device explantation were analyzed using a multiple logistic regression model (P<0.05). Results: We found significantly increased intraoperative complication rates after adjustable male sling implantation (15.9% [adjustable male sling] vs. 4.2% [AUS], P=0.003). The most frequent intraoperative complication was bladder perforation (n=17). Postoperative infection rates did not vary significantly between the respective devices (P=0.378). Device explantation rates were significantly higher after AUS implantation (9.7% [adjustable male sling] vs. 21.5% [AUS], P=0.030). In multivariate analysis, postoperative infection was a strong independent predictor of decreased device survival (odds ratio, 6.556; P=0.001). Conclusions: Complication profiles vary between adjustable male slings and AUS. Explantation rates are lower after adjustable male sling implantation. Any kind of postoperative infections are independent predictors of decreased device survival. There is no significant effect of the experience of the implanting institution on device survival.