TY  - CHAP
A1  - Mandekar, Swati
A1  - Jentsch, Lina
A1  - Lutz, Kai
A1  - Behbahani, Mehdi
A1  - Melnykowycz, Mark
T1  - Earable design analysis for sleep EEG measurements
T2  - UbiComp '21
N2  - Conventional EEG devices cannot be used in everyday life and
hence, past decade research has been focused on Ear-EEG for mobile,
at-home monitoring for various applications ranging from
emotion detection to sleep monitoring. As the area available for
electrode contact in the ear is limited, the electrode size and location
play a vital role for an Ear-EEG system. In this investigation, we
present a quantitative study of ear-electrodes with two electrode
sizes at different locations in a wet and dry configuration. Electrode
impedance scales inversely with size and ranges from 450 kΩ to
1.29 MΩ for dry and from 22 kΩ to 42 kΩ for wet contact at 10 Hz.
For any size, the location in the ear canal with the lowest impedance
is ELE (Left Ear Superior), presumably due to increased contact
pressure caused by the outer-ear anatomy. The results can be used
to optimize signal pickup and SNR for specific applications. We
demonstrate this by recording sleep spindles during sleep onset
with high quality (5.27 μVrms).
KW  - EEG
KW  - sensors
KW  - Impedance Spectroscopy
KW  - Sleep EEG
KW  - biopotential electrodes
Y1  - 2021
U6  - http://dx.doi.org/10.1145/3460418.3479328
N1  - UbiComp '21: Adjunct Proceedings of the 2021 ACM International Joint Conference on Pervasive and Ubiquitous Computing and Proceedings of the 2021 ACM International Symposium on Wearable Computers, September 21–26, 2021, Virtual, USA
SP  - 171
EP  - 175
ER  - 
TY  - JOUR
A1  - Mandekar, Swati
A1  - Holland, Abigail
A1  - Thielen, Moritz
A1  - Behbahani, Mehdi
A1  - Melnykowycz, Mark
T1  - Advancing towards Ubiquitous EEG, Correlation of In-Ear EEG with Forehead EEG
JF  - Sensors
N2  - Wearable EEG has gained popularity in recent years driven by promising uses outside of clinics and research. The ubiquitous application of continuous EEG requires unobtrusive form-factors that are easily acceptable by the end-users. In this progression, wearable EEG systems have been moving from full scalp to forehead and recently to the ear. The aim of this study is to demonstrate that emerging ear-EEG provides similar impedance and signal properties as established forehead EEG. EEG data using eyes-open and closed alpha paradigm were acquired from ten healthy subjects using generic earpieces fitted with three custom-made electrodes and a forehead electrode (at Fpx) after impedance analysis. Inter-subject variability in in-ear electrode impedance ranged from 20 kΩ to 25 kΩ at 10 Hz. Signal quality was comparable with an SNR of 6 for in-ear and 8 for forehead electrodes. Alpha attenuation was significant during the eyes-open condition in all in-ear electrodes, and it followed the structure of power spectral density plots of forehead electrodes, with the Pearson correlation coefficient of 0.92 between in-ear locations ELE (Left Ear Superior) and ERE (Right Ear Superior) and forehead locations, Fp1 and Fp2, respectively. The results indicate that in-ear EEG is an unobtrusive alternative in terms of impedance, signal properties and information content to established forehead EEG.
KW  - in-ear EEG
KW  - correlation
KW  - forehead EEG
KW  - impedance spectroscopy
KW  - biopotential electrodes
Y1  - 2022
U6  - http://dx.doi.org/10.3390/s22041568
SN  - 1424-8220
VL  - 22
IS  - 4
SP  - 1
EP  - 19
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Malzahn, Kerstin
A1  - Windmiller, Joshua Ray
A1  - Valdés-Ramírez, Gabriela
A1  - Wang, Joseph
A1  - Schöning, Michael Josef
T1  - Wearable electrochemical sensors for in situ analysis in marine environments
JF  - Analyst. 136 (2011), H. 14
Y1  - 2011
SN  - 0003-2654
SP  - 2912
EP  - 2917
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Malinowski, Daniel
A1  - Fournier, Yvan
A1  - Horbach, Andreas
A1  - Frick, Michael
A1  - Magliani, Mirko
A1  - Kalverkamp, Sebastian
A1  - Hildinger, Martin
A1  - Spillner, Jan
A1  - Behbahani, Mehdi
A1  - Hima, Flutura
T1  - Computational fluid dynamics analysis of endoluminal aortic perfusion
JF  - Perfusion
N2  - Introduction: In peripheral percutaneous (VA) extracorporeal membrane oxygenation (ECMO) procedures the femoral arteries perfusion route has inherent disadvantages regarding poor upper body perfusion due to watershed. With the advent of new long flexible cannulas an advancement of the tip up to the ascending aorta has become feasible. To investigate the impact of such long endoluminal cannulas on upper body perfusion, a Computational Fluid Dynamics (CFD) study was performed considering different support levels and three cannula positions.

Methods: An idealized literature-based- and a real patient proximal aortic geometry including an endoluminal cannula were constructed. The blood flow was considered continuous. Oxygen saturation was set to 80% for the blood coming from the heart and to 100% for the blood leaving the cannula. 50% and 90% venoarterial support levels from the total blood flow rate of 6 l/min were investigated for three different positions of the cannula in the aortic arch. 

Results: For both geometries, the placement of the cannula in the ascending aorta led to a superior oxygenation of all aortic blood vessels except for the left coronary artery. Cannula placements at the aortic arch and descending aorta could support supra-aortic arteries, but not the coronary arteries. All positions were able to support all branches with saturated blood at 90% flow volume.

Conclusions: In accordance with clinical observations CFD analysis reveals, that retrograde advancement of a long endoluminal cannula can considerably improve the oxygenation of the upper body and lead to oxygen saturation distributions similar to those of a central cannulation.
KW  - computational fluid dynamics analysis
KW  - simulation
KW  - endoluminal
KW  - aortic perfusion
KW  - extracorporeal membrane oxygenation
Y1  - 2022
U6  - http://dx.doi.org/10.1177/02676591221099809
SN  - 1477-111X
VL  - 0
IS  - 0
SP  - 1
EP  - 8
PB  - Sage
CY  - London
ER  - 
TY  - JOUR
A1  - Malan, Leone
A1  - Hamer, Mark
A1  - Känel, Roland von
A1  - Kotliar, Konstantin
A1  - Wyk, Roelof D. van
A1  - Lambert, Gavin W.
A1  - Vilser, Walthard
A1  - Ziemssen, Tjalf
A1  - Schlaich, Markus P.
A1  - Smith, Wayne
A1  - Magnusson, Martin
A1  - Wentzel, Annemarie
A1  - Myburgh, Carlien E.
A1  - Steyn, Hendrik S.
A1  - Malan, Nico T.
T1  - Delayed retinal vein recovery responses indicate both non-adaptation to stress as well as increased risk for stroke: the SABPA study
JF  - Cardiovascular Journal of Africa
Y1  - 2020
U6  - http://dx.doi.org/10.5830/CVJA-2020-031
SN  - 1680-0745
VL  - 26
IS  - 31
SP  - 1
EP  - 12
PB  - Clinics Cardive Publishing
CY  - Durbanville
ER  - 
TY  - JOUR
A1  - Maggakis-Kelemen, Christina
A1  - Digel, Ilya
A1  - Artmann, Gerhard
T1  - Polystyrene sulfonate/Polyallylamine hydrochloride microcapsules as potential artificial red blood cells - improvement of capsule flexibility
JF  - Biomedizinische Technik. 50 (2005), H. Erg.-Bd. 1
Y1  - 2005
SP  - 324
EP  - 326
ER  - 
TY  - JOUR
A1  - Maggakis-Kelemen, Christina
A1  - Biselli, Manfred
A1  - Artmann, Gerhard
T1  - Determination of the elastic shear modulus of cultured human red blood cells
JF  - Biomedizinische Technik. 47 (2002), H. Suppl. 1 Pt. 1
Y1  - 2002
SN  - 0013-5585
N1  - Druckausgabe unter 63 Z 471 vorhanden
SP  - 106
EP  - 109
ER  - 
TY  - JOUR
A1  - Lüth, H.
A1  - Thust, M.
A1  - Steffen, A.
A1  - Kordos, P.
A1  - Schöning, Michael Josef
T1  - Biochemical sensors with structured and porous silicon capacitors
JF  - Materials Science and Engineering B. 69-70 (2000)
Y1  - 2000
SN  - 0921-5107
SP  - 104
EP  - 108
ER  - 
TY  - JOUR
A1  - Lustfeld, H.
A1  - Pithan, C.
A1  - Reißel, Martin
T1  - Metallic electrolyte composites in the framework of the brick-layer model
JF  - Journal of the European Ceramic Society
N2  - It is well known that the already large dielectric constants of some electrolytes like BaTiO₃ can be enhanced further by adding metallic (e.g. Ni, Cu or Ag) nanoparticles. The enhancement can be quite large, a factor of more than 1000 is possible. The consequences for the properties will be discussed in the present paper applying a brick-layer model (BLM) for calculating dc-resistivities of thin layers and a modified one (PBLM) that includes percolation for calculating dielectric properties of these materials. The PBLM results in an at least qualitative description and understanding of the physical phenomena: This model gives an explanation for the steep increase of the dielectric constant below the percolation threshold and why this increase is connected to a dramatic decrease of the breakdown voltage as well as the ability of storing electrical energy. We conclude that metallic electrolyte composites like BaTiO₃ are not appropriate for energy storage.
Y1  - 2012
U6  - http://dx.doi.org/10.1016/j.jeurceramsoc.2011.10.017
SN  - 0955-2219
VL  - 32
IS  - 4
SP  - 859
EP  - 864
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Lustfeld, H.
A1  - Hirschfeld, J. A.
A1  - Reißel, Martin
A1  - Steffen, B.
T1  - Enhancement of precision and reduction of measuring points in tomographic reconstructions
JF  - Physics Letters A
Y1  - 2011
SN  - 0375-9601
VL  - 375
IS  - 8
SP  - 1167
EP  - 1171
PB  - Elsevier
CY  - Amsterdam
ER  -