Cyclic Mode Research Articles

Partition of topological indices of benzenoid hydrocarbons into ring contributions

AbstractThis work presents a simple method for partitioning the bond‐additive and atoms‐pair‐additive distance‐based topological indices of plane graphs into the sum of contributions of inner faces. The proposed method is applied to decompose several topological indices (Wiener, hyper‐Wiener, Tratch‐Stankevich‐Zefirov, Balaban, and Szeged indices) into the ring contributions for a series of benzenoid systems. It was found that the employed ring partitioning scheme is providing an accurate assessment of the dominant cyclic conjugation modes in the studied benzenoid hydrocarbons. Thus, the proposed method can be used as the alternative for the quantum‐chemistry‐based aromaticity indices which are significantly more computationally demanding.

Analysis of rotorcraft ground resonance with generic inter-blade damper configurations

The paper investigates the effect of inter-blade dampers with generic in-plane and out-of-plane attachment offsets on ground resonance stability proneness. An analytical formulation, considering dampers with radial offsets only is initially proposed. Sensitivity analyses show that the increase of radial offset reduces the cyclic lead-lag damping and stiffness, providing a non-zero contribution to collective terms. The analytical formulation is suitable, in a preliminary design phase, to define the optimal location of the inter-blade attachment points to avoid ground resonance phenomena and to stabilize the engine drive-train dynamics. A more detailed numerical approach is then presented to consider generic in-plane and out-of-plane attachment offsets. Ground resonance stability analyses are performed also for cases with dissimilar dampers. It is found that out-of-plane offset leads to a modification on the blade pitch-lag coupling, acting on the helicopter stability margins. However, to capture these effects it is necessary to include the overall blade motions, considering flap, lag, and pitch dynamics, together with the corresponding generalized aerodynamics forces, usually neglected in classical ground resonance analysis. Finally, the periodic stability with one damper inoperative shows how, with the radial offsets, the hybridized lead-lag collective and cyclic modes may fall into resonance conditions due to super-harmonics.

Experimental Study on Mechanical Behavior and Energy Evolution Characteristics of Gas-Filled Deep Coal under Cyclic Loading

To study the mechanical behavior and energy evolution law of gas-filled deep coal, conventional triaxial compression experiments under different confining pressure and gas pressure conditions and cyclic loading and unloading experiments under different gas pressures were carried out. The failure characteristics and mechanical parameters evolution of two loading modes were analyzed. In addition, the energy density and ratio evolution law under cyclic loading was revealed, and based on these findings, an attempt was made to depict the relation of cumulative dissipated energy density and volumetric strain by fitting the experimental data. The results indicated that failure of coal is expressed as a single shear surface under conventional compression, while under cyclic loading mode, coal behaves with multi-fracture crushing failure. Mechanical parameters showed a trend of decay with increasing gas pressure, and that cyclic loading and unloading increases the bearing capacity of coal by 8–38%. The dissipated energy density and ratio grew significantly when coal entered the yield stage. In the compaction stage, the cumulative dissipated energy density rose with volumetric strain in the form of an exponential function, and it increased with relative volumetric strain as a power function.

Housekeeping and excess entropy production for general nonlinear dynamics

We propose a housekeeping/excess decomposition of entropy production for general nonlinear dynamics in a discrete space, including chemical reaction networks and discrete stochastic systems. We exploit the geometric structure of thermodynamic forces to define the decomposition; this does not rely on the notion of a steady state, and it even applies to systems that exhibit multistability, limit cycles, and chaos. In the decomposition, distinct aspects of the dynamics contribute separately to entropy production: the housekeeping part stems from a cyclic mode that arises from external driving, generalizing Schnakenberg's cyclic decomposition to nonsteady states, while the excess part stems from an instantaneous relaxation mode that arises from conservative forces. Our decomposition refines previously known thermodynamic uncertainty relations and speed limits. In particular, it not only improves an optimal-transport-theoretic speed limit, but it also extends the optimal transport theory of discrete systems to nonlinear and nonconservative settings.

Validation of carbon isotopologue distribution measurements by GC-MS and application to 13C-metabolic flux analysis of the tricarboxylic acid cycle in Brassica napus leaves.

The estimation of metabolic fluxes in photosynthetic organisms represents an important challenge that has gained interest over the last decade with the development of 13C-Metabolic Flux Analysis at isotopically non-stationary steady-state. This approach requires a high level of accuracy for the measurement of Carbon Isotopologue Distribution in plant metabolites. But this accuracy has still not been evaluated at the isotopologue level for GC-MS, leading to uncertainties for the metabolic fluxes calculated based on these fragments. Here, we developed a workflow to validate the measurements of CIDs from plant metabolites with GC-MS by producing tailor-made E. coli standard extracts harboring a predictable binomial CID for some organic and amino acids. Overall, most of our TMS-derivatives mass fragments were validated with these standards and at natural isotope abundance in plant matrices. Then, we applied this validated MS method to investigate the light/dark regulation of plant TCA cycle by incorporating U-13C-pyruvate to Brassica napus leaf discs. We took advantage of pathway-specific isotopologues/isotopomers observed between two and six hours of labeling to show that the TCA cycle can operate in a cyclic manner under both light and dark conditions. Interestingly, this forward cyclic flux mode has a nearly four-fold higher contribution for pyruvate-to-citrate and pyruvate-to-malate fluxes than the phosphoenolpyruvate carboxylase (PEPc) flux reassimilating carbon derived from some mitochondrial enzymes. The contribution of stored citrate to the mitochondrial TCA cycle activity was also questioned based on dynamics of 13C-enrichment in citrate, glutamate and succinate and variations of citrate total amounts under light and dark conditions. Interestingly, there was a light-dependent 13C-incorporation into glycine and serine showing that decarboxylations from pyruvate dehydrogenase complex and TCA cycle enzymes were actively reassimilated and could represent up to 5% to net photosynthesis.

Simultaneous salt recovery and zwitterionic stachydrine purification from saline eluent via two-stage electrodialysis system

To date, saline eluent from the ion exchange process in the extraction of traditional Chinese medicine such as Leonurus japonicus Houtt was treated predominantly by the conventional processes such as evaporation, crystallization and ethanol elution. However, large amount of energy and fresh organic solvent need to be consumed in the above processes. In the present study, two-stage electrodialysis (ED) was proposed to simultaneously recover salt and purify zwitterionic stachydrine from the saline eluent. In the first stage ED, the membrane type and current density were optimized, and then the continuous twenty-batch operation in partial cyclic mode was carried out to increase the concentration of the recovered NaCl solution. Subsequently, the second stage ED was carried out to further purify the above desalinated saline eluent. Results indicate that, after the two-stage ED process, the concentrated NaCl solution can be directly recycled due to the high concentration of 2.9 mol/L; the recovery rate and purity of NaCl can reach to high values of 99.8% and 99.6%, respectively; the recovery rate and purity of stachydrine can reach to high values of 95.6% and 99.3%, respectively. In addition, a low energy consumption (∼8.34 kWh/m3) was required for the two-stage ED system. What’s more, the membrane fouling investigation indicated that there are as little as 0.5% of the total stachydrine in the saline eluent adsorbed into the CEM. Nonetheless, ED process can be operated stably due to the relatively stable membrane resistance and cell pair voltage drop. Hence, the two-stage ED system is a high-efficient, environmentally-friendly and economical process for simultaneous salt recovery and zwitterionic stachydrine purification from the saline eluent.

Rotation-Invariant Feature Learning via Convolutional Neural Network With Cyclic Polar Coordinates Convolutional Layer

Convolutional neural networks (CNNs) have been demonstrated to be powerful tools to automatically learn effective features from large datasets. Though features learned in CNNs are approximately scale-, translation-, and position-invariant, and their capacity in dealing with image rotations remains limited. In this article, a novel cyclic polar coordinate convolutional layer (CPCCL) is proposed for CNNs to handle the problem of rotation invariance for feature learning. First, the proposed CPCCL converts rotation variation into translation variation using polar coordinates transformation, which can easily be handled by CNNs. Moreover, cyclic convolution is designed to completely handle the translation variation converted from rotation variation by conducting convolution in a cyclic shift mode. Note that the proposed CPCCL is capable of generalization and can be used as a preprocessing layer for classification CNNs to learn the rotation-invariant feature. Extensive experiments over three benchmark datasets demonstrate that the proposed CPCCL can clearly handle the rotation-sensitive problem in traditional CNNs and outperforms several state-of-the-art rotation-invariant feature learning algorithms.

Effect of thermal cyclic nitriding modes on microstructure and chemical composition of titanium alloy surface layers

A method has been developed for cyclic low-temperature ion nitriding using a plasma source with an integrally cold hollow cathode, which is superior in performance to a source with an incandescent cathode. The results of the effectiveness of the developed method are presented. It has been established that the greatest influence on the microhardness of titanium alloys is exerted by the bias voltage and the l ocation of the surface with respect to the plasma flow. Microstructural studies have shown that the α-phase is stabilized in the near-surface layer due to nitrogen diffusion, grain growth is not observed. Alloy VT8M1 retains a two-phase structure. The possibility of controlling nitriding by changing the duration and direction of surface saturation is also shown.

Patch Amperometry and Intracellular Patch Electrochemistry.

Both patch amperometry (PA) and intracellular patch electrochemistry (IPE) take advantage of a recording configuration where an electrochemical detector-carbon fiber electrode (CFE)-is housed inside a patch pipette. PA, which is employed in cell-attached or excised inside-out patch clamp configuration, offers high-resolution patch capacitance measurements with simultaneous amperometric detection of catecholamines released during exocytosis. The method provides precise information on single-vesicle size and quantal content, fusion pore conductance, and permeability of the pore for catecholamines. IPE, on the other hand, measures cytosolic catecholamines that diffuse into the patch pipette following membrane rupture to achieve the whole-cell configuration. In amperometric mode, IPE detects total catechols, whereas in cyclic voltammetric mode, it provides more specific information on the nature of the detected molecules and may selectively quantify catecholamines, providing a direct approach to determine cytosolic concentrations of catecholaminergic transmitters and their metabolites. Here, we provide detailed instructions on setting up PA and IPE, performing experiments and analyzing the data.

EVALUATION OF THE ENERGY EFFICIENCY OF THE NEW MODEL OF SUCKER-ROD PUMPING UNIT

As is known, in world, oil production is carried out both in the sea and in oil fields on land. For the mechanized exploitation of oil fields on land, in most cases used different type of sucker-rod pumps. The main object of the study of the article is a new constructive solution of the pumping unit, the novelty of which is approved by the ownership certificates. The main factor characterizing the operation of pumping units is its quality indicators such as metal consumption, reliability, efficiency and energy consumption. When switching from a balanced sucker-rod pumping unit to an unbalanced the efficiency factor decreases from 0.834 to 0.65 and the operating power factor decreases from 0.605 to 0.312. In this case, power losses increase sharply not only in transmissions, but also in energy distribution networks. If the engine is not fully loaded or is not selected correctly, then these energy coefficients decrease even more. The selection of engine power is performed according to the worst conditions, i.e. the cyclic mode of operation of an unbalanced pumping unit. Despite this, it can be said that in almost all oil fields, the power of asynchronous motors is greatly exaggerated, which causes additional losses. In article proposed expressions for determining the optimal power of the electric motor were proposed, taking into account the efficiency factor of the balancing device during the balancing of the proposed new constructive solution of the beamless pumping unit with a combined, movable counter weights and rotary counter weights. This allows to prevent excess energy consumption and reduce energy costs. Which is very important in the era of globalization, when energy prices are rising sharply.

Disposable Wearable Sensors Based on Nanocellulose for Biomedical Applications

Monitoring of human motor and muscle activity is used in many areas, from prosthetics during rehabilitation to training monitoring of athletes. Sensors for these tasks are usually made of flexible polymers and require recycling after the expiration date. Nanocellulose (NC) can be used as a biodegradable base for this type of sensor. The development of low-cost disposable sensors that do not require disinfection and cleaning is relevant. NC is a composite nanoscale structure of cellulose fibers (fibrils) with a high aspect ratio. The paper aim is to develop disposable wearable biodegradable bend sensors based on nanocellulose using vacuum synthesis methods and the study of their characteristics. Nanocellulose was synthesized by the TEMPO method. The sensors were created by means of magnetron sputtering of Ti/Ni or Cr/Ni thin films at the surface of nanocellulose. Measuring stand was developed to determine the change in resistance due to the bending of the sensor. It’s mechanical part consists of an elastic deformation plate made of high-alloy steel, which can be bent using a micrometric screw. The change in resistance is linearly related to the elongation of the measured sample. A Wheatstone bridge and a 24-Bit ADC HX711 were used to measure the change in resistance. During testing of the sensor for analysis of muscle activity, the sensor element was attached to the human skin with the help of medical glue BF-6. The obtained sensors were tested for biodegradability. The samples were placed in the ground at a depth of 20-30 mm. The mass of nanocellulose samples was measured using a high-precision digital balance EDIS 50 (50/0.001 g) with a built-in level. The optimal ratio of the value of sensitivity and reversibility is observed in the range of the nominal resistance of the nickel film from 10 to 100 Ohms. This is due to an increase in the surface area of ​​the Ni film, which leads to an increase in sensitivity, but at the same time there is a decrease in the repeatability of the characteristics due to a greater influence of the heterogeneous structure of nanofibrillated cellulose. In addition, sensors with different buffer layer materials - Ti and Cr - were selected for testing. For titanium-based sensors, the maximum sensitivity coefficient is 0.312%, while the deviation of the sensor signal after one bending-unfolding cycle (reversibility) is less than 0.001%. Chromium-based sensors have significantly higher sensitivity (0.9753%), but worse reversibility (7.14%). Sensors based on the Cr buffer layer showed poorly reproducible results in the cyclic mode of operation, namely: there are significant fluctuations in the signal amplitude (up to 50-60%) already after the second bending-unfolding cycle. Therefore, despite the high sensitivity of such sensors, they are unsuitable for analyzing human motor and muscle activity/ The sensors based on the Ti buffer layer showed good response (2.5-3%) and good repeatability and resistance to cyclic bending (30 times). It can be seen that the obtained dependencies are approximated by a linear law. Some deviation from linearity is obviously related to the inhomogeneity of the Ni thin film. Also, the sensors showed a good loss of mass (40% in 9 weeks) during the biodegradability test, which confirms their ability to decompose under the influence of atmospheric phenomena. So, in this work, disposable wearable sensors on a nanocellulose substrate were synthesized for the evaluation of motor and muscle activity of a person. It was found that such sensors can be used to test of finger and biceps movement during at least 10-30 full flexion-extension cycles. For test of elbow movement, it is planned to synthesize a high-elastic composite material based on nanocellulose and bioelastic material (for example, polyvinyl alcohol). Thus, the proposed sensor manufacturing technology makes it possible to obtain cheap, light, flexible disposable wearable sensors that do not require further disposal after the end of operation.

Electrically conductive hybrid organic crystals as flexible optical waveguides

Hybrid materials capitalize on the properties of individual materials to attain a specific combination of performance assets that is not available with the individual components alone. We describe a straightforward approach to preparation of sandwich-type hybrid dynamic materials that combine metals as electrically conductive components and polymers as bending, momentum-inducing components with flexible organic crystals as mechanically compliant and optically transducive medium. The resulting hybrid materials are conductive to both electricity and light, while they also respond to changes in temperature by deformation. Depending on the metal, their conductivity ranges from 7.9 to 21.0 S µm‒1. The elements respond rapidly to temperature by curling or uncurling in about 0.2 s, which in one typical case corresponds to exceedingly fast deformation and recovery rates of 2187.5° s‒1 and 1458.3° s‒1, respectively. In cyclic operation mode, their conductivity decreases less than 1% after 10,000 thermal cycles. The mechanothermal robustness and dual functionality favors these materials as candidates for a variety of applications in organic-based optics and electronics, and expands the prospects of application of organic crystals beyond the natural limits of their dynamic performance.

Memory surfaces separating the processes of monotonous and cyclic loads

The processes of elastoplastic deformation of structural materials can consist of a sequence of monotonous and cyclic loading regimes, in which peculiar effects and features arise. Mathematical modeling of such processes, as well as resource assessment and forecasting, is a very difficult task. In addition, the analysis of transient processes from cyclic to monotonous and from monotonous to cyclic shows the need to separate these processes. Based on the analysis of the results of experimental studies of samples of stainless steel 12Х18Н10T under a rigid (controlled deformation) deformation process, which is a sequence of monotonic and cyclic loading modes, under conditions of uniaxial tension-compression at normal temperature, the features and differences in the processes of monotonic and cyclic loading are revealed. To describe these features and separate the processes of monotonic and cyclic loading modes in the theories of plastic flow with combined hardening, various variants of memory surfaces are introduced. An analysis of the results of experimental studies of stainless steel showed that in the space of the plastic strain tensor, the size of the memory surface is determined by the range of plastic strains, and the position of the center is determined by the values of average plastic strains under cyclic loading. Various variants of the memory surface are considered, their capabilities and disadvantages are identified, and the most adequate variant of the memory surface is determined. To confirm the operability of this version of the memory surface, together with the equations of the Bondar plasticity model, the calculated and experimental results were compared and a reliable agreement was obtained between these results both in terms of the kinetics of the stress-strain state and in terms of the number of cycles to failure.

Beamline-implemented stretching devices for in situ X-ray scattering experiments

Two recently developed experimental devices for investigating soft matter deformation are presented. Both devices exploit the capabilities of a modern synchrotron beamline to enable advanced and highly precise materials-science experiments in which X-ray scattering is registered. The devices can be operated both in monotonic as well as cyclic mode and are implemented into a beamline at DESY, Hamburg (Germany). Hence, relevant experimental parameters, such as displacement, force and temperature, are recorded synchronously with the individual X-ray scattering patterns. In addition, spatial variation of materials deformation can be monitored and recorded with optical microscopy. This unique sample environment enables in situ X-ray experiments in transmission, i.e. small- or wide-angle X-ray scattering (SAXS or WAXS), and in grazing-incidence geometry, i.e. grazing-incidence (GI-) SAXS or WAXS. One device with stepper motors is designed for studies of slow, (quasi-) static deformation and the other one with pneumatic actuators can be used for fast, impact deformation. Both devices are available to external beamline users, too.

Cyclic fatigue vs static loading for shear bond strength test of lithium disilicate and dentin substrates: A comparison of resin cement viscosities.

To explore the effect of resin cement viscosities on the shear bond strength under static and fatigue load of lithium disilicate and dentin substrates. Bonded tri-layer samples (lithium disilicate ceramic cylinder, resin cement, and substrate - ceramic or dentin) was performed considering 2 factors (n=15): "resin cement viscosity" (high, HV; or low, LV) and "loading mode" (static, s-SBS; or fatigue shear bond strength, f-SBS). The specimens were subjected to s-SBS (1mm/min, 1kN load cell) and f-SBS (cyclic fatigue, initial load: 10N; step-size: 5N; 10,000 cycles/step; underwater). Failure mode, topography, and finite element analysis (FEA) were performed. The resin cement viscosity did not influence the s-SBS and f-SBS of lithium disilicate substrate; however, it affected the bond strength to dentin, with HV presenting the worst fatigue behavior (f-SBS=6.89MPa). Cyclic loading in shear testing induced a notorious detrimental effect with a relevant decrease (16-56%) in bond strength and survival rates, except for dentin substrate and LV. Most failures were adhesive. A distinct pattern comparing the disilicate and dentin was identified and FEA demonstrated that there was a stress concentration on the top of the cement layer. Cyclic fatigue loading in shear testing has detrimental effects on the adhesive behavior and survival probabilities of bonded lithium disilicate sets, regardless of resin cement viscosity. In contrast, resin cement viscosity affects the bond strength and the survival rates of dentin substrate submitted to cyclic loading mode, in which a low viscosity results in better performance.

Damage and Fatigue Fracture of Structural Elements in Various Cyclic Loading Modes

Damage and Fatigue Fracture of Structural Elements in Various Cyclic Loading Modes

Calibration of Thermal Dissipation Probes for Xylem Sap Flow in the Wood of a Diffuse-Porous and a Conifer Species under Cyclic Heating

The most popular sap flow measurement technique uses thermal dissipation probes. Differences in wood characteristics and the natural temperature gradient between probes have affected the accuracy and applicability of the sap flow equation. In addition, the continued heat of the probe can also cause thermal damage to tree tissue. The objectives of this study were to use cyclic heating and calibrate the probes with two species: Pinus bungeana Zucc. And Salix matsudana Koidz., two typical diffuse-porous species. This experiment evaluated a thermal dissipation probe in three heating modes: continuous heating, 10 min heating and 50 min cooling (10/50), and 30 min heating and 30 min cooling (30/30). The heating modes were evaluated on two species. Temperature differences between the heating needle and the control needle under different heating modes and transpiration water consumption (whole-tree weighing method) were observed simultaneously. The sap flow estimation equation under cyclic heating mode was established by analyzing the relationship between the sap flow rate and the values obtained from whole-tree weighing. The results showed that the original equation underestimated sap flow rate of P. bungeana and S. matsudana by 67% and 60%. Under the cyclic heating modes, the modified equations were different from the original equation, and their accuracy was improved. After verification, the corrected equations [Fd = 0.0264K0.738 (P. bungeana, 30/30, R2 = 0.67), Fd = 0.0722K1.113(S. matsudana, 30/30, R2 = 0.60), Fd is the sap flow density, K is temperature coefficient] reduced the influence of the natural temperature gradient on the estimation of sap flow rate, thereby significantly improving the accuracy of sap flow rate estimation. The resulting equation may be more suitable for actual field observations of sap flow in the two tested species. The cyclic heating mode has the potential to measure plant transpiration for extended periods in the field.

STUDY OF THE WELDABILITY OF STEELS OF DIFFERENT ALLOYING COMPOSITIONS FOR THE LARGE-DIAMETER PIPES TRANSPORTING HYDROGEN SULPHIDE-CONTAINING GAS

Increased resistance to brittle fracture in any zone of the welded joint is one of the main requirements for quality of steel pipes for transportation of the hydrogen sulphide gas, which determines the relevance of identification of the reasons of the impact toughness decrease of the welded joint area. The purpose of the study was to investigate the microstructure formation features of the seam zone of pipes made of low-carbon steels of different chemical composition. The effect of microstructure of the coarse-grained area of the heat affected zone on toughness of welded joint has been estimated by the laboratory thermal cycling testing complex Gleeble 3180. The samples with cross-section of 10×10×110 mm made of commercially available steel grades 04ХНДБ, 06ГНФБ and 05ХГБ (Russian Standard) with different contents of niobium and manganese were used as material for the research. To eliminate the effect of heating rate and holding time in austenitic region on the microstructure, the simulation was carried out in a cyclic mode with the same heating rate up to 1350 °С and subsequent cooling to 800 °С. The cooling rate in the interval 800–500 °C varied from 2 to 64 °C/s. The microstructure formation of the seam zone was studied by scanning electron microscopy and reflected electron diffraction. Despite the differences in chemical composition, the studied steels showed similar microstructure after simulation of the coarse-grained area of the heat-affected zone. For all the steels an increase in the share of rack bainite and the density of high angle boundaries with increasing cooling rate was found. It was established that at close values of average grain size of ferrite in the samples from steel 04ХНДБ the grain homogeneity is higher due to decrease in size and quantity of the largest grains. In specimens made of 05ХГБ and 06ГНФБ steel grades, the impact toughness of simulated coarse-grained area of the heat affected zone stabilizes at high level due to formation of more favorable dispersed structure when cooling rate increases more than 8 °C/s.

Heterogeneous-structured Ti-6Al-4V with enhanced mechanical properties in monotonic and cyclic deformation modes

This study aimed to develop heterogeneous-structured (HS) Ti-6Al-4V composed of coarse and fine grains to enhance the alloy's mechanical properties. This microstructure was induced by selective activation of dynamic globularization by using water-quenching and subsequent rolling below the β-transus temperature. Microstructures and mechanical properties of the HS alloy in monotonic and cyclic deformation modes were compared with those of coarse-grained (CG) and ultrafine-grained (UFG) counterparts. HS Ti-6Al-4V had a higher mechanical strength and better resistance to low-cycle fatigue (LCF) fracture without the loss of ductility compared with commercial mill-annealed CG alloy, and HS alloy had an engineering advantage of low-cost mass production in contrast to UFG counterpart, despite their similar mechanical properties under both monotonic and cyclic deformations. The enhanced mechanical properties of HS alloy were attributed to the presence of UFG region and the partial transformation of transverse to basal texture with a high intensity. Such conditions gave rise to an active slip transfer, low internal stress, and high strain compatibility, thereby leading to the high LCF resistance.

A rapid in vitro electrochemical screening of extracellular matrix of Saccharomyces cerevisiae by palladium nanoparticles-modified electrodes

Herein, a rapid electrochemical screening of yeasts (Saccharomyces cerevisiae) in vitro mode depending on their optical density, cultivation time and growth medium used was conducted in 3 min by palladium nanoparticles (Pd-NPs)-modified electrodes. Pd-NPs-modified electrodes operated in cyclic voltammetry mode at low scan rates, i.e. 5–20 mV/s supported a low oxidative process in the yeast extracellular matrix. The electrochemical screening relied on an efficient electrooxidation of secondary metabolites, i.e. organohydrazines formed in the extracellular medium as a result of microbial activity of yeast cells.More importantly, during the study the impact of fundamental parameters, viz. type of the matrix and pH on electroanalytical response of Pd-NPs-based electrodes in real fermentation medium was investigated in detail. The efficiency of the proposed in vitro electrochemical screening of yeast extracellular matrix was not affected by pH of the samples or composition of the multicomponent medium, but more likely exclusively depended on the presence of organohydrazines. The potential of this electroanalytical approach towards profiling of the extracellular matrix of Saccharomyces cerevisiae was compared with results obtained by gas chromatography mass-spectrometry (GC–MS) and genetically encoded biosensor (ro-GFP2) assays.