Molekularbiologische Affinitätsstudien : neue Anwendungen elektrophoretischer, miniaturisierter Trennsysteme

Molecular biological affinity studies is a field with an abundance of interesting analytical methods. The following work summarises the current methods in a short overview before focussing on the electrophoretic measurements. They belong to an active area of research, which is suitable for a large spectrum of applications. The possibility to transfer affinity studies from capillary to a miniaturised system – the chip – is the main aim of this work. In the age of high throughput screening, fast new analytical methods are required and miniaturised systems, such as the electrophoretic chip, become a common demand. Up-to-now the application of EMSA (electrophoretic mobility shift assay) was only used on capillary. Here it was successfully transferred for the first time to a planar miniaturised system. In order to characterise the microchip, known systems (neurotransmitters and cyclodextrins) have been measured. As for the binding parameters, the measurements proofed that chips deliver the same results as the capillary, however in a shorter time and with less material consumption. Apart from measurements with neurotransmitters, studies with artificial receptors and peptides, with single-stranded DNA and metal cations have been accomplished. The results of the binding affinities have been compared to calorimetric measurements and confirmed the quality of the ACE (affinity capillary electrophoresis) measurements on chip. By choosing certain oligonucleotide sequences and suited buffer systems, the binding selectivity of metal ions for tetranucleotides could be shown. Considering the building of binary and tertiary complexes, which depends on the kind of buffer molecules, the binding constants and the amount of binding partners were calculated. Although not the same number of measurements has been compiled for the microchip as for the capillary, in principal the suitability of the chip to examine non-covalent bindings to oligonucleotides and DNA strands was shown. Methodical specialities as well as qualitative differences between measurements on the capillary and on the chip have been observed and documented. In some areas of research, important for electrophoretic ACE measurements, chips are superior to capillary. The smaller amount of probes and buffer and the shorter separation time, which allows the measurement of instable systems, all speak in favour of the chip. Due to the significantly shorter separation times, the phenomenon of diffusion has a distinctly smaller impact on the peak broadening. This improves the separation efficiency. High separation efficiency is important for ACE analytics, especially so when the separation is done in seconds. The worse sensitivity of the chip could only be put down to technical peculiarities and less efficient detection systems of the chips used here. Although capillaries with normal separation lengths deliver qualitatively better results at the moment, the microchip will be superior to the classical capillary electrophoresis as soon as reliable injection methods are available and the steering of probe and separation media are solved, additional to its present advantages

Quantification of single-stranded nucleic acid and oligonucleotide interactions with metal ions by affinity capillary electrophoresis: part I

The interactions between oligonucleotides and inorganic cations have been measured by capillary zone electrophoresis. With increasing concentrations of divalent cations (Ca2+, Mg2+, Mn2+ and Ni2+) in the running buffer, the migration behavior was evaluated by calculation of the binding constants. Besides these fundamental studies of binding equilibria, different buffer components, tris(hydroxymethyl)aminomethane and 3-(N-morpholino)propanesulfonic acid, have been investigated and their effects on metal ion binding quantifie

Coronary collaterals and risk for restenosis after percutaneous coronary interventions: a meta-analysis

<p>Abstract</p> <p>Background</p> <p>The benefit of the coronary collateral circulation (natural bypass network) on survival is well established. However, data derived from smaller studies indicates that coronary collaterals may increase the risk for restenosis after percutaneous coronary interventions. The purpose of this systematic review and meta-analysis of observational studies was to explore the impact of the collateral circulation on the risk for restenosis.</p> <p>Methods</p> <p>We searched the MEDLINE, EMBASE and ISI Web of Science databases (2001 to 15 July 2011). Random effects models were used to calculate summary risk ratios (RR) for restenosis. The primary endpoint was angiographic restenosis > 50%.</p> <p>Results</p> <p>A total of 7 studies enrolling 1,425 subjects were integrated in this analysis. On average across studies, the presence of a good collateralization was predictive for restenosis (risk ratio (RR) 1.40 (95% CI 1.09 to 1.80); <it>P </it>= 0.009). This risk ratio was consistent in the subgroup analyses where collateralization was assessed with intracoronary pressure measurements (RR 1.37 (95% CI 1.03 to 1.83); <it>P </it>= 0.038) versus visual assessment (RR 1.41 (95% CI 1.00 to 1.99); <it>P </it>= 0.049). For the subgroup of patients with stable coronary artery disease (CAD), the RR for restenosis with 'good collaterals' was 1.64 (95% CI 1.14 to 2.35) compared to 'poor collaterals' (<it>P </it>= 0.008). For patients with acute myocardial infarction, however, the RR for restenosis with 'good collateralization' was only 1.23 (95% CI 0.89 to 1.69); <it>P </it>= 0.212.</p> <p>Conclusions</p> <p>The risk of restenosis after percutaneous coronary intervention (PCI) is increased in patients with good coronary collateralization. Assessment of the coronary collateral circulation before PCI may be useful for risk stratification and for the choice of antiproliferative measures (drug-eluting stent instead bare-metal stent, cilostazol).</p

Cerebral cortex expression of Gli3 is required for normal development of the lateral olfactory tract

<div><p>Formation of the lateral olfactory tract (LOT) and innervation of the piriform cortex represent fundamental steps to allow the transmission of olfactory information to the cerebral cortex. Several transcription factors, including the zinc finger transcription factor Gli3, influence LOT formation by controlling the development of mitral cells from which LOT axons emanate and/or by specifying the environment through which these axons navigate. <i>Gli3</i> null and hypomorphic mutants display severe defects throughout the territory covered by the developing lateral olfactory tract, making it difficult to identify specific roles for <i>Gli3</i> in its development. Here, we used <i>Emx1Cre</i>;<i>Gli3</i>^<i>fl/fl</i> conditional mutants to investigate LOT formation and colonization of the olfactory cortex in embryos in which loss of <i>Gli3</i> function is restricted to the dorsal telencephalon. These mutants form an olfactory bulb like structure which does not protrude from the telencephalic surface. Nevertheless, mitral cells are formed and their axons enter the piriform cortex though the LOT is shifted medially. Mitral axons also innervate a larger target area consistent with an enlargement of the piriform cortex and form aberrant projections into the deeper layers of the piriform cortex. No obvious differences were found in the expression patterns of key guidance cues. However, we found that an expansion of the piriform cortex temporally coincides with the arrival of LOT axons, suggesting that <i>Gli3</i> affects LOT positioning and target area innervation through controlling the development of the piriform cortex.</p></div

A first update on mapping the human genetic architecture of COVID-19

peer reviewe

Switch-matrix-based Monolithic CMOS Platform Featuring a Large Array of Carbon Nanotube Sensor Elements and a 96-channel Readout Circuitry

We present a monolithic CMOS biosensor system comprised of a switch-matrix-based array of carbon nanotube field-effect transistors (CNT-FETs) and an associated readout circuitry. The switch-matrix allows for flexible selection and simultaneous routing of 96 sensor elements to the readout channels. The resistances of the CNT-FETs were measured by applying a constant voltage and measuring the resulting current. Variation of the first-stage-amplifier gain and bandwidth allows for measuring resistances in the range between 50 kΩ and 20 MΩ at a bandwidth of up to 20 kHz. A parallel integration of the CNT-FETs has been achieved by using a floating electrode dielectrophoresis (DEP) manipulation technique

Monolithic CMOS sensor platform featuring an array of 9'216 carbon-nanotube-sensor elements and low-noise, wide-bandwidth and wide-dynamic-range readout circuitry

ISSN:0925-400

Development of a Novel Home-Based Exergame With On-Body Feedback: Usability Study.

BACKGROUND With more than 1.4 billion adults worldwide classified as physically inactive, physical inactivity is a public health crisis leading to an increased risk of cardiometabolic diseases. Motivating and engaging training strategies are needed to tackle this public health crisis. Studies have shown that exergames, games controlled by active body movements, are potentially usable, attractive, and effective tools for home-based training. The ExerCube (by Sphery Ltd) has been developed as a physically immersive and adaptive functional fitness game. The development of a home-based version of the ExerCube could increase accessibility, reduce barriers to exercise, and provide an attractive solution to improve physical and cognitive health. OBJECTIVE The aim was threefold: (1) to develop a usable home-based exergame system, (2) to evaluate the usability and training experience of the home-based exergame and its early-stage on-body feedback system, and (3) to identify avenues for further user-centered design iterations of the system. METHODS A total of 15 healthy participants (mean age 25, SD 3 years) completed 2 laboratory visits consisting of four 5-minute exergame sessions. In each session, the on-body feedback system provided a different feedback modality (auditory, haptic, and visual feedback) to the participant. Following the second visit, participants completed a range of assessments, including the System Usability Scale (SUS), the Physical Activity Enjoyment Scale (PACES), the Flow Short Scale (FSS), the Immersive Experience Questionnaire (IEQ), and a rating of perceived exertions (RPEs) both physically and cognitively. Participants answered questions regarding the on-body feedback system and completed a semistructured interview. RESULTS Usability was rated as acceptable, with a SUS score of 70.5 (SD 12). The questionnaires revealed medium-to-high values for the training experience (FSS: 5.3, SD 1; PACES: 5.3, SD 1.1; IEQ: 4.7, SD 0.9. Physical (mean 4.8, SD 1.6) and cognitive (mean 3.9, SD 1.4) RPEs were moderate. Interviews about the on-body feedback system revealed that the majority of participants liked the haptic feedback and the combination of haptic and auditory feedback the best. Participants enjoyed the distinct perceptibility, processing, and integration of the exergame and its supportive and motivating effect. The visual feedback was perceived less positively by participants but was still classified as "potentially" helpful. The auditory feedback was rated well but highlighted an area for further improvement. Participants enjoyed the training experience and described it as motivating, interactive, immersive, something new, interesting, self-explanatory, as well as physically and cognitively challenging. Moreover, 67% (n=10) of the participants could imagine exercising at home and continuing to play the exergame in the future. CONCLUSIONS The home-based exergame and its early-stage on-body feedback system were rated as usable and an enjoyable training experience by a young healthy population. Promising avenues emerged for future design iterations