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Abstract Gold electrodes have been used in a wide range of electrochemical biosensors because their functionalization process with thiols has been well described and, in general, they offer good chemical stability. However, one of the most commonly used redox-pairs in electrochemical impedance spectroscopy, Hexacyanoferrate (II)/(III), causes corrosion of the gold electrodes and consequently damages the surface modification. This leads to alterations of the sensing signals, and thus, renders the quantitative and sensitive detection of target molecules virtually impossible. To overcome this problem we introduced the in-situ generation of Hexaammineruthenium (II)/(III) as redox-pair during the impedimetric measurement by applying a DC-bias. This DC-bias was chosen in such a way that it supplied Hexaammineruthenium (II) in a suitable concentration at the electrode surface by reducing Hexaammineruthenium (III). We compared the stability of photolithographically fabricated thin-film and screen-printed gold electrodes in Hexacyanoferrate and Hexaammineruthenium solutions. Further, long-time characterization of the electrochemical properties with cyclic voltammetry and electrochemical impedance spectroscopy revealed that Hexaammineruthenium (II)/(III) was an excellent redox-pair for stable impedimetric measurements with gold electrodes. To demonstrate the suitability of Hexaammineruthenium for biosensing we applied it for the impedimetric detection of human-IgG. This biosensor exhibited a linear range from 11.3 ng/mL to 113 μg/mL, which is a suitable range for diagnostic applications. Highlights • Corrosion problems with HCF independent of electrode fabrication and SAM thickness. • Alternative redox-couple for impedimetric bio-sensor with increased stability. • Hexaammineruthenium (III) is used; DC-bias generates reduced state in-situ. • A stable IgG biosensor with redox-probe Hexaammineruthenium (II)/(III) is realized. [ABSTRACT FROM AUTHOR]

Abstract: In classical DNA chip analysis, the target DNA moves by diffusion and Brownian motion only. We introduce a system for enhancing the signals and reducing the hybridization times of bio chips. It allows active agitation within the hybridization buffer by controlled movement of magnetic particles within the analyte solution. First results show that the system easily achieves specific fluorescent signals about four times higher than the ones obtained by a referencing standard procedure within the same hybridization time, while unspecific signals remain unchanged. The device can easily be applied to existing bio chip applications and allows universal operation in the field of molecular diagnostics. [Copyright &y& Elsevier]

Improving the explainability of Computer Vision models based on Deep Learning has recently become a compelling problem, ensuring reliable predictions to the end-user and enabling more fine-grained classifications. Recently, Concept Bottleneck models have been proposed for images classification, partitioning the problem in two stages and thereby defining a hierarchy of concepts. So far, however, little work has been done to investigate the applicability of this approach to other datasets with higher intra-class variability and ambiguity, and to discuss its flexibility to tasks different from whole-images classification. In this work we develop and discuss a Concept Bottleneck model for images segmentation, objects fine classification and tracking, and compare it to more classical methods based on Mask R-CNN and images similarity algorithms. All our models are trained and tested on a dataset comprised of pictures of fridges filled with various objects, however the method can be applied to any fine classification task. The proposed model makes full use of the hierarchy in concepts, exploiting the relationships between different categories at the same hierarchical level and relying on a novel method for handling multi-labels classifications. We show that the performance on fine classification is on par with a regular Mask R-CNN, but with a significant increase in explainability and in handling classes confusion. New explainable metrics are proposed to quantitatively evaluate the increase in explainability. We also demonstrate the effectiveness of the derived Concept Bottleneck features on related tasks, i.e., the tracking of objects between consecutive pictures in a sequence. The code is released as open source and available at https://opensource.silicon-austria.com/pittinof/hierarchical-concept-bottleneck. [ABSTRACT FROM AUTHOR]

In this work we investigate the magnetic field dependence of the precession frequency of vortex states in spin-valve nanocontacts with an amorphous CoFeB free layer and an artificial antiferromagnet as polarizer. The nanocontacts have radii between 70 and 90 nm. We show that the excitation frequency in these devices responds to small, in-plane magnetic fields along the easy and hard axis directions. The characteristics of the frequency response depend on the generated magnetic configuration under the nanocontact. This, in turn, results from the combined effect of the applied magnetic field and the current-generated Oersted field. Taking also into account the relative large nanocontact radii, a variety of vortex excitation modes can arise with distinctive frequency versus field responses, some of which could be considered for magnetic field sensing applications. [ABSTRACT FROM PUBLISHER]

This paper presents a small microcontroller-based sine-wave generator for probe signals of a wide range of amplitudes and frequencies, which requires very little energy so that it can be used for wireless applications in biosensing. The presented realization generates a 10-kHz sine wave with a 100-mV peak-to-peak voltage. Its total harmonic distortion is less than 0.15%, and the spurious free dynamic range excluding harmonics is about 85 dB. The generator's total power consumption at a 3.3-V supply voltage and without output buffers is less than 3.5 mW. This value includes the power requirement of the microcontroller's internal 8-MHz clock generator and is below the power needs of current direct-digital-synthesis-based signal generators. The presented concept bases on commercially available electronic components and is implemented for probe signal generation in wireless batteryless tags for long-term impedance measurements on standard microbiological cell cultures. The included microcontroller enables the use of a phase-controlled trigger signal and other simultaneous control functions, e.g., for peripheral components and data communication. [ABSTRACT FROM AUTHOR]

Positive effects of exercise on cancer prevention and progression have been proposed to be mediated by stimulating natural killer (NK) cells. Because NK cell receptors are regulated by epigenetic modifications, we investigated whether acute aerobic exercise and training change promoter DNA methylation and gene expression of the activating KIR2DS4 and the inhibiting KIR3DL1 gene. Sixteen healthy women (50-60 years) performed a graded exercise test (GXT) and were randomized into either a passive control group or an intervention group performing a four-week endurance exercise intervention. Blood samples (pre-, post-GXT and post-training) were used for isolation of DNA/RNA of NK cells to assess DNA promoter methylation by targeted deep-amplicon sequencing and gene expression by qRT-PCR. Potential changes in NK cell subsets were determined by flow cytometry. Acute and chronic exercise did not provoke significant alterations of NK cell proportions. Promoter methylation decreased and gene expression increased for KIR2DS4 after acute exercise. A high gene expression correlated with a low methylation of CpGs that were altered by acute exercise. Chronic exercise resulted in a minor decrease of DNA methylation and did not alter gene expression. Acute exercise provokes epigenetic modifications, affecting the balance between the activating KIR2DS4 and the inhibiting KIR3DL1, with potential benefits on NK cell function. [ABSTRACT FROM AUTHOR]

Abstract: Biosensor systems which enable impedance measurements on adherent cell layers under label-free conditions are considered powerful tools for monitoring specific biological characteristics. A radio frequency identification-based sensor platform was adopted to characterize cultivation and differentiation of human bone marrow-derived multipotent stem cells (bmMSC) over periods of up to several days and weeks. Electric cell-substrate impedance sensing was achieved through fabrication of sensitive elements onto glass substrates which comprised two comb-shaped interdigitated gold electrodes covering an area of 1.8mm×2mm. The sensing systems were placed into the wells of a 6-well tissue culture plate, stacked onto a reader unit and could thus be handled and operated under sterile conditions. Continuous measurements were carried out with a sinusoidal voltage of 35mV at a frequency of 10kHz. After seeding of human bmMSC, this sensor was able to trace significant impedance changes contingent upon cell spreading and adhesion. The re-usable system was further proven suitable for live examination of cell-substrate attachment or continuous cell monitoring up to several weeks. Induction of either osteogenic or adipogenic differentiation could be validated in bmMSC cultures within a few days, in contrast to state-of-the-art protocols, which require several weeks of cultivation time. In the context of medical cell production in a GMP-compliant process, the here presented interdigitated electric microsensor technology allows the documentation of MSC quality in a fast, efficient and reliable fashion. [Copyright &y& Elsevier]