Publications by authors named "Nadejda Krasteva"

A microfluidic tongue-on-a-chip platform has been evaluated relative to the known sensory properties of various sweeteners. Analogous metrics of typical sensory features reported by human panels such as sweet taste thresholds, onset, and lingering, as well as bitter off-flavor and blocking interactions were deduced from the taste receptor activation curves and then compared. To this end, a flow cell containing a receptor cell array bearing the sweet and six bitter taste receptors was transiently exposed to pure and mixed sweetener samples.

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The present study aimed to investigate whether the perception of still scenes in a virtual environment in congruent versus incongruent condition can be influenced by odors. Ninety healthy participants were divided into three groups, including two experimental virtual reality (VR) environments: a rose garden, an orange basket, and a control condition. In each VR condition, participants were exposed to a rose odor, an orange odor, or no odor, resulting in congruent, incongruent, and control conditions.

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Purpose: The olfactory system can be successfully rehabilitated with regular, intermittent stimulation during multiple daily exposures to selected sets of odors, i.e., olfactory training (OT).

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RNA aptamers for tumor necrosis factor-alpha (TNFα), for which functionality was demonstrated in L929 cells, show only little affinity for the protein in vitro. Detailed investigation of the aptamer-protein interaction by surface plasmon resonance and quartz crystal microbalance analysis revealed that affinity is not the only crucial parameter for efficacy and functionality of those aptamers. Instead, the sensitive equilibrium of the monomeric and homotrimeric form of soluble TNFα decides on aptamer binding.

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The interaction between lipid bilayers in water has been intensively studied over the last decades. Osmotic stress was applied to evaluate the forces between two approaching lipid bilayers in aqueous solution. The force-distance relation between lipid mono- or bilayers deposited on mica sheets using a surface force apparatus (SFA) was also measured.

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Cytokine proteins are known as biomarker molecules, characteristic of a disease or specific body condition. Monitoring of the cytokine pattern in body fluids can contribute to the diagnosis of diseases. Here we report on the development of an array comprised of different anti-cytokine antibodies on an activated solid support coupled with a fluorescence readout mechanism.

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Although the identification of the multigene family encoding mammalian olfactory receptors were identified more than 20 years ago, we are far from understanding olfactory perception because of the difficulties in functional expression of these receptors in heterologous cell systems. Cell-free (CF) or in vitro expression systems offer an elegant alternative route to cell based protein expression, as the functional expression of membrane proteins can be directly achieved from the genetic template without the need of cell cultivation and protein isolation. Here we investigated in detail the cell-free expression and membrane insertion of the olfactory receptor OR5 in dependence of different experimental conditions like probing different origins of the cell-free expression system (from bacteria, via plants and insects toward mammalian system) and lipid composition of the respective extracts.

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This work is about gas biosensing with a cytochrome c biosensor. Emphasis is put on the analysis of the sensing process and a mathematical model to make predictions about the biosensor response. Reliable predictions about biosensor responses can provide valuable information and facilitate biosensor development, particularly at an early development stage.

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Gold-nanoparticle/organic films were prepared via layer-by-layer self-assembly using dodecylamine-stabilised Au-nanoparticles and poly(propyleneimine) (PPI) dendrimers of generation one to five (G1-G5) or hexadecanedithiol (HDT) as linker compounds. TEM and FE-SEM images revealed that the bulk of the films consisted of nanoparticles with diameters of about 4 nm. XPS was used to study the chemical composition of the films.

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