TY  - JOUR
A1  - Rodrigues, Raul T.
A1  - Morais, Paulo V.
A1  - Nordi, Cristina S. F.
A1  - Schöning, Michael Josef
A1  - Siqueira Jr., José R.
A1  - Caseli, Luciano
T1  - Carbon Nanotubes and Algal Polysaccharides To Enhance the Enzymatic Properties of Urease in Lipid Langmuir-Blodgett Films
JF  - Langmuir
N2  - Algal polysaccharides (extracellular polysaccharides) and carbon nanotubes (CNTs) were adsorbed on dioctadecyldimethylammonium bromide Langmuir monolayers to serve as a matrix for the incorporation of urease. The physicochemical properties of the supramolecular system as a monolayer at the air–water interface were investigated by surface pressure–area isotherms, surface potential–area isotherms, interfacial shear rheology, vibrational spectroscopy, and Brewster angle microscopy. The floating monolayers were transferred to hydrophilic solid supports, quartz, mica, or capacitive electrolyte–insulator–semiconductor (EIS) devices, through the Langmuir–Blodgett (LB) technique, forming mixed films, which were investigated by quartz crystal microbalance, fluorescence spectroscopy, and field emission gun scanning electron microscopy. The enzyme activity was studied with UV–vis spectroscopy, and the feasibility of the thin film as a urea sensor was essayed in an EIS sensor device. The presence of CNT in the enzyme–lipid LB film not only tuned the catalytic activity of urease but also helped to conserve its enzyme activity. Viability as a urease sensor was demonstrated with capacitance–voltage and constant capacitance measurements, exhibiting regular and distinctive output signals over all concentrations used in this work. These results are related to the synergism between the compounds on the active layer, leading to a surface morphology that allowed fast analyte diffusion owing to an adequate molecular accommodation, which also preserved the urease activity. This work demonstrates the feasibility of employing LB films composed of lipids, CNT, algal polysaccharides, and enzymes as EIS devices for biosensing applications.
Y1  - 2018
U6  - http://dx.doi.org/10.1021/acs.langmuir.7b04317
SN  - 1520-5827
VL  - 34
IS  - 9
SP  - 3082
EP  - 3093
PB  - ACS Publications
CY  - Washington, DC
ER  - 
TY  - JOUR
A1  - Röhlen, Desiree
A1  - Pilas, Johanna
A1  - Dahmen, Markus
A1  - Keusgen, Michael
A1  - Selmer, Thorsten
A1  - Schöning, Michael Josef
T1  - Toward a Hybrid Biosensor System for Analysis of Organic and Volatile Fatty Acids in Fermentation Processes
JF  - Frontiers in Chemistry
N2  - Monitoring of organic acids (OA) and volatile fatty acids (VFA) is crucial for the control of anaerobic digestion. In case of unstable process conditions, an accumulation of these intermediates occurs. In the present work, two different enzyme-based biosensor arrays are combined and presented for facile electrochemical determination of several process-relevant analytes. Each biosensor utilizes a platinum sensor chip (14 × 14 mm²) with five individual working electrodes. The OA biosensor enables simultaneous measurement of ethanol, formate, d- and l-lactate, based on a bi-enzymatic detection principle. The second VFA biosensor provides an amperometric platform for quantification of acetate and propionate, mediated by oxidation of hydrogen peroxide. The cross-sensitivity of both biosensors toward potential interferents, typically present in fermentation samples, was investigated. The potential for practical application in complex media was successfully demonstrated in spiked sludge samples collected from three different biogas plants. Thereby, the results obtained by both of the biosensors were in good agreement to the applied reference measurements by photometry and gas chromatography, respectively. The proposed hybrid biosensor system was also used for long-term monitoring of a lab-scale biogas reactor (0.01 m³) for a period of 2 months. In combination with typically monitored parameters, such as gas quality, pH and FOS/TAC (volatile organic acids/total anorganic carbonate), the amperometric measurements of OA and VFA concentration could enhance the understanding of ongoing fermentation processes.
Y1  - 2018
U6  - http://dx.doi.org/10.3389/fchem.2018.00284
IS  - 6
PB  - Frontiers
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Lapitan, Denis G.
A1  - Rogatkin, Dmitrii A.
A1  - Persheyev, Sydulla K.
A1  - Kotliar, Konstantin
T1  - False spectra formation in the differential two-channel scheme of the laser Doppler flowmeter
JF  - Biomedizinische Technik
N2  - Noise in the differential two-channel scheme of a classic laser Doppler flowmetry (LDF) instrument was studied. Formation of false spectral components in the output signal due to beating of electrical signals in the differential amplifier was found out. The improved block-diagram of the flowmeter was developed allowing to reduce the noise.
Y1  - 2018
U6  - http://dx.doi.org/10.1515/bmt-2017-0060
SN  - 0013-5585
VL  - 63
IS  - 4
SP  - 439
EP  - 444
PB  - De Gruyter
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Miyamoto, Koichiro
A1  - Seki, Kosuke
A1  - Suto, Takeyuki
A1  - Werner, Frederik
A1  - Wagner, Torsten
A1  - Schöning, Michael Josef
A1  - Yoshinobu, Tatsuo
T1  - Improved spatial resolution of the chemical imaging sensor with a hybrid illumination that suppresses lateral diffusion of photocarriers
JF  - Sensor and Actuators B: Chemical
N2  - The chemical imaging sensor is a semiconductor-based chemical sensor capable of visualizing pH and ion distributions. The spatial resolution depends on the lateral diffusion of photocarriers generated by illumination of the semiconductor substrate. In this study, two types of optical setups, one based on a bundle of optical fibers and the other based on a binocular tube head, were developed to project a hybrid illumination of a modulated light beam and a ring-shaped constant illumination onto the sensor plate. An improved spatial resolution was realized by the ring-shaped constant illumination, which suppressed lateral diffusion of photocarriers by enhanced recombination due to the increased carrier concentration.
Y1  - 2018
U6  - http://dx.doi.org/10.1016/j.snb.2018.07.016
SN  - 0925-4005
VL  - 273
SP  - 1328
EP  - 1333
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Rittweger, Jörn
A1  - Albracht, Kirsten
A1  - Flück, Martin
A1  - Ruoss, Severin
A1  - Brocca, Lorenza
A1  - Longa, Emanuela
A1  - Moriggi, Manuela
A1  - Seynnes, Olivier
A1  - Di Giulio, Irene
A1  - Tenori, Leonardo
A1  - Vignoli, Alessia
A1  - Capri, Miriam
A1  - Gelfi, Cecilia
A1  - Luchinat, Claudio
A1  - Franceschi, Claudio
A1  - Bottinelli, Roberto
A1  - Cerretelli, Paolo
A1  - Narici, Marco
T1  - Sarcolab pilot study into skeletal muscle’s adaptation to longterm spaceflight
JF  - npj Microgravity
Y1  - 2018
U6  - http://dx.doi.org/10.1038/s41526-018-0052-1
SN  - 2373-8065
VL  - 4
IS  - 1
SP  - 1
EP  - 9
PB  - Nature Portfolio
ER  - 
TY  - JOUR
A1  - Bialonski, Stephan
A1  - Wellmer, Jörg
A1  - Elger, Christian E.
A1  - Lehnertz, Klaus
T1  - Interictal focus localization in neocortical lesional epilepsies with synchronization cluster analysis
JF  - Epilepsia
Y1  - 2006
SN  - 0013-9580
VL  - 47
SP  - 36
ER  - 
TY  - JOUR
A1  - Bialonski, Stephan
A1  - Lehnertz, Klaus
T1  - Identifying phase synchronization clusters in spatially extended dynamical systems
JF  - Physical Review E
Y1  - 2006
U6  - http://dx.doi.org/10.1103/PhysRevE.74.051909
SN  - 2470-0053
VL  - 74
IS  - 5
SP  - 051909
ER  - 
TY  - JOUR
A1  - Lehnertz, Klaus
A1  - Mormann, Florian
A1  - Osterhage, Hannes
A1  - Andy, Müller
A1  - Prusseit, Jens
A1  - Chernihovskyi, Anton
A1  - Staniek, Matthäus
A1  - Krug, Dieter
A1  - Bialonski, Stephan
A1  - Elger, Christian E.
T1  - State-of-the-art of seizure prediction
JF  - Journal of Clinical Neurophysiology
Y1  - 2007
U6  - http://dx.doi.org/10.1097/WNP.0b013e3180336f16
SN  - 1537-1603
VL  - 24
IS  - 2
SP  - 147
EP  - 153
ER  - 
TY  - JOUR
A1  - Allefeld, Carsten
A1  - Bialonski, Stephan
T1  - Detecting synchronization clusters in multivariate time series via coarse-graining of Markov chains
JF  - Physical Review E
Y1  - 2007
U6  - http://dx.doi.org/10.1103/PhysRevE.76.066207
SN  - 2470-0053
VL  - 76
IS  - 6
SP  - 066207
ER  - 
TY  - JOUR
A1  - Bialonski, Stephan
A1  - Schindler, K.
A1  - Elger, C. E.
A1  - Lehnertz, Klaus
T1  - Lateralized characteristics of the evolution of EEG correlation during focal onset seizures: a mechanism to prevent secondary generalization?
JF  - Epilepsia
N2  - Rationale: Previous studies [Topolnik et al., Cereb Cortex 2003; 13: 883; Schindler et al., Brain 2007; 130: 65] indicate that the termination of focal onset seizures may be causally related to an increase of global neuronal correlation during the second half of the seizures. This increase was observed to occur earlier in complex partial seizures than in secondarily generalized seizures. We here address the question whether such an increase of neuronal correlation prior to seizure end is indeed a global phenomenon, involving both hemispheres or whether there are side-specific differences. Methods: We analyzed 20 focal onset seizures (10 complex partial, 10 secondarily generalized seizures) recorded in 13 patients who underwent presurgical evaluation of focal epilepsies of different origin. EEG was recorded intracranially from bilaterally implanted subdural strip and intrahippocampal depth electrodes. Utilizing a moving window approach, we investigated the evolution of the maximum cross correlation for all channel combinations during seizures. For each moving window the mean value of the maximum cross correlation (MCC) between all electrode contacts was computed separately for each hemisphere. After normalization of seizure durations, MCC values of the ipsi- and contralateral hemisphere for all seizures were determined. Results: We observed that the MCC of the contralateral hemisphere in complex partial seizures increased during the first half of the seizure, whereas, for the same time interval, the MCC of the ipsilateral hemisphere even declined below the level of the pre-seizure period. In contrast, no significant differences between both hemispheres could be observed for secondarily generalized seizures where both hemispheres showed a simultaneous increase of MCC during the second half of the seizures. The level of MCC for the contralateral hemisphere was higher for complex partial seizures than for secondarily generalized seizures during the first half of the seizure. Conclusions: Our findings indicate that there are indeed lateralized differences in the evolution of global neuronal correlation during complex partial and secondarily generalized seizures. The observed contralateral increase of neuronal correlation during complex partial seizures might indicate an emerging self-organizing mechanism for preventing the spread of seizure activity.
Y1  - 2008
SN  - 0013-9580
VL  - 49
SP  - 11
EP  - 11
ER  -