Stress-induced Shifts Research Articles

A new FEM-based approach on the modeling of stress-induced velocity shift of piezoelectric surface acoustic wave resonators

A new FEM-based approach on the modeling of stress-induced velocity shift of piezoelectric surface acoustic wave resonators

Diamond-based HBAR as a high-pressure sensor

Features of an application of a High-overtone Bulk Acoustic Resonator (HBAR) as a high-pressure sensor have been considered. In this way, the second version of an integrated measurement system combining a Diamond Anvil Cell (DAC) and an HBAR operating in the microwave frequency band from 1.3 to 3.7 GHz was developed. A specific configuration of HBAR based on a piezoelectric layered structure as “Al/ASN/Mo/(100) diamond” was proposed. Two independent methods of pressure control were used to calibrate the embedded HBAR as a pressure sensor: a stress-induced shift of the diamond Raman line and the shift of the R1 luminescence line of Cr3+ in the ruby matrix. A stable correlation between the frequency shifts of the acoustic overtones in the HBAR, the shift of the diamond Raman line and the shift of the R1 line with a change in pressure applied to the W-gasket with embedded ruby particles was established in the range of 0 … 30 GPa. The sensitivity of an investigated sensor to the pressure variation was found to be equal 1ΔPΔff=4.8∙10-4GPa-1. The maximal value of 30 GPa obtained in a given work can be easily increased after a minor reconfiguration of the DAC. Considering the range of 0 − 5 GPa a proposed built-in DAC acoustoelectronic sensor has the better performance and sensitivity compared with known methods of a pressure measurement.

Acute stress during witnessing injustice shifts third-party interventions from punishing the perpetrator to helping the victim.

People tend to intervene in others' injustices by either punishing the transgressor or helping the victim. Injustice events often occur under stressful circumstances. However, how acute stress affects a third party's intervention in injustice events remains open. Here, we show a stress-induced shift in third parties' willingness to engage in help instead of punishment by acting on emotional salience and central-executive and theory-of-mind networks. Acute stress decreased the third party's willingness to punish the violator and the severity of the punishment and increased their willingness to help the victim. Computational modeling revealed a shift in preference of justice recovery from punishment the offender toward help the victim under stress. This finding is consistent with the increased dorsolateral prefrontal engagement observed with higher amygdala activity and greater connectivity with the ventromedial prefrontal cortex in the stress group. A brain connectivity theory-of-mind network predicted stress-induced justice recovery in punishment. Our findings suggest a neurocomputational mechanism of how acute stress reshapes third parties' decisions by reallocating neural resources in emotional, executive, and mentalizing networks to inhibit punishment bias and decrease punishment severity.

Optimization of Recombinant Protein Production in Synechococcus elongatus PCC 7942: Utilizing Native Promoters and Magnetic Fields.

The cyanobacterium Synechococcus elongatus PCC 7942 holds significant potential as a biofactory for recombinant protein (RP) production due to its capacity to harness light energy and utilize CO2. This study aimed to enhance RP production by integration of native promoters and magnetic field application (MF) in S. elongatus PCC 7942. The psbA2 promoter, which responds to stress conditions, was chosen for the integration of the ZsGreen1 gene. Results indicated successful gene integration, affirming prior studies that showed no growth alterations in transgenic strains. Interestingly, exposure to 30 mT (MF30) demonstrated a increase in ZsGreen1 transcription under the psbA2 promoter, revealing the influence of MF on cyanobacterial photosynthetic machinery. This enhancement is likely attributed to stress-induced shifts in gene expression and enzyme activity. MF30 positively impacted photosystem II (PSII) without disrupting the electron transport chain, aligning with the "quantum-mechanical mechanism" theory. Notably, fluorescence levels and gene expression with application of 30 mT were significantly different from control conditions. This study showcases the efficacy of utilizing native promoters and MF for enhancing RP production in S. elongatus PCC 7942. Native promoters eliminate the need for costly exogenous inducers and potential cell stress. Moreover, the study expands the scope of optimizing RP production in photoautotrophic microorganisms, providing valuable insights for biotechnological applications.

Locally resolved stress measurement in the ultra-hard composites polycrystalline diamond and polycrystalline cubic boron nitride

Cutting tools made of the ultra-hard composites polycrystalline diamond and polycrystalline boron nitride are being used in more and more sectors of machining. Due to the laborious preparation processes such as grinding, brushing, electrical discharge and laser machining, the subsurface of these tools is strongly stressed mechanically and thermally. This also changes the residual stress state in the highly loaded cutting edge area. The measurement of these residual stresses is not possible by established XRD methods due to the highly curved surface of the cutting edge. The measurement method Raman spectroscopy shows high potential for this application, but conversion factors are necessary for the application. These factors enable the conversion of the stress-induced peak shift in the Raman spectrum into absolute residual stress values. Previous conversion factors are mainly based on hydrostatic load cases, which, however, cannot be transferred to the application on cutting tools. In this work, axial load cases were provided by bending and conversion factors were determined by comparing XRD stress measurements and Raman peak shifts. The conversion factors determined were then plotted against existing results from other studies and the causes for the deviations that occurred were determined. By this, for the first time, a conversion factor for an axial load case for cubic boron nitride could be determined and it could be shown that, as for diamond, it differs significantly from the hydrostatic load case.

Effects of Mycobacterium vaccae NCTC 11659 and Lipopolysaccharide Challenge on Polarization of Murine BV-2 Microglial Cells.

Previous studies have shown that the in vivo administration of soil-derived bacteria with anti-inflammatory and immunoregulatory properties, such as Mycobacterium vaccae NCTC 11659, can prevent a stress-induced shift toward an inflammatory M1 microglial immunophenotype and microglial priming in the central nervous system (CNS). It remains unclear whether M. vaccae NCTC 11659 can act directly on microglia to mediate these effects. This study was designed to determine the effects of M. vaccae NCTC 11659 on the polarization of naïve BV-2 cells, a murine microglial cell line, and BV-2 cells subsequently challenged with lipopolysaccharide (LPS). Briefly, murine BV-2 cells were exposed to 100 µg/mL whole-cell, heat-killed M. vaccae NCTC 11659 or sterile borate-buffered saline (BBS) vehicle, followed, 24 h later, by exposure to 0.250 µg/mL LPS (Escherichia coli 0111: B4; n = 3) in cell culture media vehicle (CMV) or a CMV control condition. Twenty-four hours after the LPS or CMV challenge, cells were harvested to isolate total RNA. An analysis using the NanoString platform revealed that, by itself, M. vaccae NCTC 11659 had an "adjuvant-like" effect, while exposure to LPS increased the expression of mRNAs encoding proinflammatory cytokines, chemokine ligands, the C3 component of complement, and components of inflammasome signaling such as Nlrp3. Among LPS-challenged cells, M. vaccae NCTC 11659 had limited effects on differential gene expression using a threshold of 1.5-fold change. A subset of genes was assessed using real-time reverse transcription polymerase chain reaction (real-time RT-PCR), including Arg1, Ccl2, Il1b, Il6, Nlrp3, and Tnf. Based on the analysis using real-time RT-PCR, M. vaccae NCTC 11659 by itself again induced "adjuvant-like" effects, increasing the expression of Il1b, Il6, and Tnf while decreasing the expression of Arg1. LPS by itself increased the expression of Ccl2, Il1b, Il6, Nlrp3, and Tnf while decreasing the expression of Arg1. Among LPS-challenged cells, M. vaccae NCTC 11659 enhanced LPS-induced increases in the expression of Nlrp3 and Tnf, consistent with microglial priming. In contrast, among LPS-challenged cells, although M. vaccae NCTC 11659 did not fully prevent the effects of LPS relative to vehicle-treated control conditions, it increased Arg1 mRNA expression, suggesting that M. vaccae NCTC 11659 induces an atypical microglial phenotype. Thus, M. vaccae NCTC 11659 acutely (within 48 h) induced immune-activating and microglial-priming effects when applied directly to murine BV-2 microglial cells, in contrast to its long-term anti-inflammatory and immunoregulatory effects observed on the CNS when whole-cell, heat-killed preparations of M. vaccae NCTC 11659 were given peripherally in vivo.

Abundance of Oligoflexales bacteria is associated with algal symbiont density, independent of thermal stress in Aiptasia anemones.

Many multicellular organisms, such as humans, plants, and invertebrates, depend on symbioses with microbes for metabolic cooperation and exchange. Reef-building corals, an ecologically important order of invertebrates, are particularly vulnerable to environmental stress in part because of their nutritive symbiosis with dinoflagellate algae, and yet also benefit from these and other microbial associations. While coral microbiomes remain difficult to study because of their complexity, the anemone Aiptasia is emerging as a simplified model. Research has demonstrated co-occurrences between microbiome composition and the abundance and type of algal symbionts in cnidarians. However, whether these patterns are the result of general stress-induced shifts or depletions of algal-associated bacteria remains unclear. Our study aimed to distinguish the effect of changes in symbiont density and thermal stress on the microbiome of symbiotic Aiptasia strain CC7 by comparing them with aposymbiotic anemones, depleted of their native symbiont, Symbiodinium linucheae. Our analysis indicated that overall thermal stress had the greatest impact on disrupting the microbiome. We found that three bacterial classes made up most of the relative abundance (60%-85%) in all samples, but the rare microbiome fluctuated between symbiotic states and following thermal stress. We also observed that S. linucheae density correlated with abundance of Oligoflexales, suggesting these bacteria may be primary symbionts of the dinoflagellate algae. The findings of this study help expand knowledge on prospective multipartite symbioses in the cnidarian holobiont and how they respond to environmental disturbance.

Melatonin Does Not Affect the Stress-Induced Phase Shifts of Peripheral Clocks in Male Mice.

Repeated or chronic stress can change the phase of peripheral circadian rhythms. Melatonin (Mel) is thought to be a circadian clock-controlled signal that might play a role in synchronizing peripheral rhythms, in addition to its direct suppressing effects on the stress axis. In this study we test whether Mel can reduce the social-defeat stress-induced phase shifts in peripheral rhythms, either by modulating circadian phase or by modulating the stress axis. Two experiments were performed with male Mel-deficient C57BL/6J mice carrying the circadian reporter gene construct (PER2::LUC). In the first experiment, mice received night-restricted (ZT11-21) Mel in their drinking water, resulting in physiological levels of plasma Mel peaking in the early dark phase. This treatment facilitated re-entrainment of the activity rhythm to a shifted light-dark cycle, but did not prevent the stress-induced (ZT21-22) reduction of activity during stress days. Also, this treatment did not attenuate the phase-delaying effects of stress in peripheral clocks in the pituitary, lung, and kidney. In a second experiment, pituitary, lung, and kidney collected from naive mice (ZT22-23), were treated with Mel, dexamethasone (Dex), or a combination of the two. Dex application affected PER2 rhythms in the pituitary, kidney, and lung by changing period, phase, or both. Administering Mel did not influence PER2 rhythms nor did it alleviate Dex-induced delays in PER2 rhythms in those tissues. We conclude that exogenous Mel is insufficient to affect peripheral PER2 rhythms and reduce stress effects on locomotor activity and phase changes in peripheral tissues.

Abstract 15426: Stress-Induced Transcriptomic Shift in Human iPSC-Derived Cardiomyocytes Carrying Hypertrophic Cardiomyopathy Associated MYH7 G256E Mutation

Introduction: Hypertrophic cardiomyopathy (HCM) is a monogenic disorder caused by heterozygous (HET) mutations in sarcomere genes such as MYH7. Recently, human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) carrying HET HCM mutations have shed new insights into the molecular mechanisms of HCM. However, it remains unclear whether the cellular phenotypes of low penetrant mutations such as MYH7 G256E and others, can be adequately elucidated. Hypothesis: We hypothesize that the incorporation of cellular stressors can enhance the manifestation of pathogenic HCM phenotypes in low penetrant MYH7 mutations. Methods: We generated HET and homozygous (HOM) hiPSC-lines for mutation G256E in the MYH7 locus, which is associated with HCM. We performed single-cell RNA sequencing (scRNAseq) with CellPlex technology on wildtype (WT), HET, and HOM iPSC-CMs at day 30 and 60 of cardiac differentiation to establish baseline cellular transcriptional phenotype. We then treated day 30 hiPSC-CMs with 1μM isoproterenol treatment for 5 days or glucose starvation for 10 days and performed scRNAseq to assess their transcriptional shift. Additional Digital Droplet PCR studies were performed to investigate the MYH7 mutant allele expression. Results: In day 30 iPSC-CMs we detected a large clone-to-clone and batch-to-batch variability transcriptionally that obscured the identification of a consistent mutant phenotype in HET MYH G256E vs WT hiPSC lines. These phenotypes correlated with a 1:1 ratio of mutant vs WT allele expression. Implementation of long-term culture or treatment with isoproterenol or glucose starvation led to enhanced hypertrophic and oxidative phosphorylation gene expression in HET hiPSC-CMs. Intriguingly, the expression of MYH6 increased in MYH7-mutant hiPSC-CMs. Conclusions: The application of cellular stressors can enhance the manifestation of hypertrophic phenotypes in HET MYH G256E hiPSC-CMs and suggests a potential mechanism for the variable penetrance of MYH7 mutations in HCM patients.

Chitosan-induced biotic stress tolerance and crosstalk with phytohormones, antioxidants, and other signalling molecules.

Several polysaccharides augment plant growth and productivity and galvanise defence against pathogens. Such elicitors have ecological superiority over traditional growth regulators, considering their amplified biocompatibility, biodegradability, bioactivity, non-toxicity, ubiquity, and inexpensiveness. Chitosan is a chitin-derived polysaccharide that has recently been spotlighted among plant scientists. Chitosan supports plant growth and development and protects against microbial entities such as fungi, bacteria, viruses, nematodes, and insects. In this review, we discuss the current knowledge of chitosan's antimicrobial and insecticidal potential with recent updates. These effects are further explored with the possibilities of chitosan's active correspondence with phytohormones such as jasmonic acid (JA), salicylic acid (SA), indole acetic acid (IAA), abscisic acid (ABA), and gibberellic acid (GA). The stress-induced redox shift in cellular organelles could be substantiated by the intricate participation of chitosan with reactive oxygen species (ROS) and antioxidant metabolism, including hydrogen peroxide (H2O2), superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). Furthermore, we propose how chitosan could be intertwined with cellular signalling through Ca2+, ROS, nitric oxide (NO), transcription factors (TFs), and defensive gene activation.

In Situ Monitoring of Curing Reaction in Solid Composite Propellant with Fiber-Optic Sensors.

Curing activity in the preparation of solid composite propellants determines the performance of solid rocket motors in operation. Limited by the lack of effective monitoring tools, the complete curing behavior and thermal-induced curing kinetics are rarely disclosed. It is still a challenge to monitor in situ and in real-time the physical and chemical cross-linking reaction during the curing of propellant. Herein, we demonstrate a promising approach based on optical fiber capable of being implanted inside the propellant to monitor the internal stress evolution during the curing process, by taking hydroxyl-terminated polybutadiene propellant as an example. Attributed to the strain and temperature sensitivity of a pair of optical fiber gratings, the thermal-assisted physico-chemical cross-linking states of curing process have been demonstrated in detail. By tracking the stress-induced wavelength shifts of fiber gratings and calculating the curing mechanism function, the complete curing roadmap, including the viscous flow stage, gel stage, hardening stage can be clearly revealed, and the curing completion times are obtained as 154, 81, and 40 h, at the curing temperatures of 60, 70, and 80 °C, respectively. The apparent activation energy of this curing system obtained by calculation is 73.88 kJ/mol. This flexible fiber-based sensor provides an effective tool for unraveling the cure kinetic mechanism, and paves a universal pathway to guide the preparation and applications of versatile composite materials for solid rocket motors.

Evolution of magnetic stripes under uniaxial stress in La1.885Ba0.115CuO4 studied by neutron scattering

We present the effect of uniaxial stress on the magnetic stripes in the cuprate system ${\mathrm{La}}_{2\ensuremath{-}x}{\mathrm{Ba}}_{x}{\mathrm{CuO}}_{4}$ with $x=0.115$, previously found to have a stress-induced enhancement in the superconducting transition temperature. By means of neutron scattering, we confirm that the static stripes are suppressed by stress, pointing towards a trade-off between superconductivity and static magnetism, in direct agreement with previously reported muon spin rotation measurements. Additionally, we show that some of the reduced weight in the elastic channel appears to have moved to the inelastic channel, while we can exclude the opening of a spin gap down to an energy of 1 meV. Moreover, a stress-induced momentum shift of the fluctuations towards the typical 1/8 value of commensurability is observed, while no change in periodicity is seen in the static stripe signal. These results impose a strong constraint on the theoretical interpretation of stress-enhanced superconductivity in cuprate systems.

Does stress consistently favor habits over goal-directed behaviors? Data from two preregistered exact replication studies

Instrumental learning is controlled by two distinct parallel systems: goal-directed (action-outcome) and habitual (stimulus-response) processes. Seminal research by Schwabe and Wolf (2009, 2010) has demonstrated that stress renders behavior more habitual by decreasing goal-directed control. More recent studies yielded equivocal evidence for a stress-induced shift towards habitual responding, yet these studies used different paradigms to evaluate instrumental learning or used different stressors. Here, we performed exact replications of the original studies by exposing participants to an acute stressor either before (cf. Schwabe and Wolf, 2009) or directly after (cf. Schwabe and Wolf, 2010) an instrumental learning phase in which they had learned that distinct actions led to distinct, rewarding food outcomes (i.e., instrumental learning). Then, following an outcome devaluation phase in which one of the food outcomes was consumed until participants were satiated, action-outcome associations were tested in extinction. Despite successful instrumental learning and outcome devaluation and increased subjective and physiological stress levels following stress exposure, the stress and no-stress groups in both replication studies responded indifferently to valued and devalued outcomes. That is, non-stressed participants failed to demonstrate goal-directed behavioral control, thereby rendering the critical test of a shift from goal-directed to habitual control in the stress group inapt. Several reasons for these replication failures are discussed, including the rather indiscriminate devaluation of outcomes that may have contributed to indifferent responding during extinction, which emphasize the need to further our understanding of the boundary conditions in research aimed at demonstrating a stress-induced shift towards habitual control.

Adrenalectomy prevents the effects of social defeat stress on PER2 rhythms in some peripheral tissues in male mice

While stress does not affect the phase or period of the central pacemaker in the suprachiasmatic nucleus, it can shift clocks in peripheral tissues. Our previous studies showed significant delays of the PER2 rhythms in lung and kidney following social defeat stress. The mechanism underlying these effects is not fully understood, but might involve glucocorticoids (GC) released during the stressor. In the present study, we performed social defeat stress in adrenalectomized (ADX) mice to see if the induction of endogenous GC is necessary for the stress-induced phase shifts of peripheral clocks. We used mice that carry a luciferase reporter gene fused to the circadian clock gene Period2 (PER2::LUC) to examine daily rhythms of PER2 expression in various peripheral tissues. Mice were exposed to 5 consecutive daily social defeat stress in the late dark phase (ZT21–22). Running wheel rotations were recorded during 7 baseline and 5 social defeat days, which showed that social defeat stress suppressed locomotor activity without affecting the phase of the rhythm. This suppression of activity was not prevented by ADX. One hour after the last stressor, tissue samples from the liver, kidney and lung were collected and cultured for ex vivo bioluminescence recordings. In the liver, PER2 rhythms were not affected by social defeat stress or ADX. In the kidney, social defeat stress caused a > 4 h phase delay of the PER2 rhythm, which was prevented by ADX, supporting the hypothesis of a crucial role of GC in this stress effect. In the lung, social defeat stress caused an 8 h phase delay, but, surprisingly, a similar phase delay was seen in ADX animals independent of defeat. The latter indicates complex effects of stress and stress hormones on the lung clock. In conclusion, the findings show that repeated social defeat stress in the dark phase can shift PER2 rhythms in some tissues (lung, kidney) and not others (liver). Moreover, the social defeat stress effect in some tissues appears to be mediated by glucocorticoids (kidney) whereas the mechanism in other tissues is more complex (lung).

Neuron-Glia-Ratio-Like Approach Evidenced for Limited Variability and In-Aggregate Circadian Shifts in Cortical Cell-Specific Transcriptomes.

Regardless of shifts in levels of individual transcripts, it remains elusive whether natural variability in cell-specific transcriptomes within the cerebral cortex is limited in aggregate. It is also unclear whether cortical cell-specific transcriptomes might change dynamically in absence of cell number changes. Total variation in neuron- and glia-specific in-aggregate transcriptomes could be identified in a model-free way via glia-neuron ratio approach, by univariate median-to-median ratios comparing integral levels of cell-specific transcripts within a tissue sample. When deleterious, regenerative or developmental events affecting cortical cell numbers were subtle, median-to-median ratios demonstrated within-group variability not exceeding <20-25% in most cases. These levels of total variability might be explained in part by limited (~5-10%) circadian and stress-induced shifts in cell-specific cortical transcriptomes. Relevant in-aggregate transcriptomic alterations were identified after shifts in cell numbers induced by well-validated deleterious events including ischemia, traumatic injury, microglia's activation/depletion or specific mutations. Cortical median-to-median ratios also follow naturally occurring changes in the numbers of excitatory, inhibitory neurons and glial cells during perinatal brain development. These findings characterize cortical cell-specific transcriptomes as subjects to circadian shifts and lifetime events, urging the importance of reporting full details on an origin of any transcriptomic sample collected in vivo.

Physics-Based Compact Model of Current Stress-Induced Threshold Voltage Shift in Top-Gate Self-Aligned Amorphous InGaZnO Thin-Film Transistors

Threshold voltage shift ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta {V}_{\text{T}}$ </tex-math></inline-formula> ) under various current stress (CS) conditions need to be quantitatively studied in self-aligned top-gate amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs). Here, we propose a stretched-exponential function (SEF)-based <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta {V}_{\text{T}}$ </tex-math></inline-formula> model that can be applied to various combinations of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text{GS}}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text{DS}}$ </tex-math></inline-formula> . The proposed model indicates the characteristic electron trapping time constant <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\tau _{1}$ </tex-math></inline-formula> is inversely proportional to ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text{GS}} - {V}_{\text{T}}$ </tex-math></inline-formula> ). In contrast, the time constant <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\tau _{2}$ </tex-math></inline-formula> is directly proportional to the square root of ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text{DS}}+{V}_{\text{bi}}$ </tex-math></inline-formula> ), presumably due to the local donor creation by a lateral electric field. The proposed model was verified experimentally in various <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text{GS}}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text{DS}}$ </tex-math></inline-formula> configurations. Further, it is confirmed that the lateral electric field dominantly influences donor creation near the drain.

Influence of stress on the electromechanical properties and the phase transitions of lead-free (1 − x)Ba(Zr0.2Ti0.8)O3–x(Ba0.7Ca0.3)TiO3

The influence of stress on the phase boundaries of polycrystalline lead-free perovskite (1 − x)Ba(Zr0.2Ti0.8)O3–x(Ba0.7Ca0.3)TiO3 (x = 0.4, 0.5, and 0.6) was characterized through the temperature- and stress-dependent small-signal dielectric and piezoelectric response from − 150 to 200 °C under uniaxial compressive stress up to − 75 MPa. For all three compositions, the phase transition temperatures separating the rhombohedral, orthorhombic, tetragonal, and cubic phases were shifted to higher temperatures with an increase in the uniaxial mechanical loading, corresponding to a significant decrease in the dielectric and piezoelectric responses. Additional stress-dependent relative permittivity measurements up to − 260 MPa were conducted at four different constant temperatures (− 10, 10, 25, and 40 °C), revealing significant increases in the dielectric response, making these materials interesting for tunable dielectric applications. Furthermore, the stress-induced shift in phase transition temperatures was confirmed by in situ combined temperature- and stress-dependent Raman spectroscopy measurements under different constant uniaxial loads within the temperature range from 30 to 130 °C.Graphical abstract

К вопросу о механизмах повышения проницаемости стенки кишечника при стрессе

One of the manifestations of the stress reaction in the colon is an increase in the permeability of its wall due to the development of an inflammatory reaction against the background of changes in neuroendocrine regulation and microbiota state. These processes are accompanied by significant changes in humoral homeostasis and cell activity involved in the development of an inflammatory response in the colon wall. We performed a literature review to analyze and summarize the available research data on the mechanisms of stress-induced changes in the intestine at the molecular, cellular and tissue levels involving the regulatory systems of the body. Scientific information was searched in Web Of Science, Scopus, ScienceDirect, Medline, Russian Science Citation Index (RSCI), as well as in the search engines Google Scholar, PubMed, Semantic Scholar, Taylor &amp; Francis, Wiley Online Library and Bielefeld Academic Search Engine (BASE). Wall permeability has been shown to have a rather complex regulation involving corticotropin-releasing factor, mast cells, dendritic cells, eosinophils, macrophages, Substance P, nerve growth factor, neurotensin, microbiota metabolic factors (serotonin, short-chain fatty acids, indole derivatives and conjugated fatty acids), epigenetic mechanisms, the HES1 (Hairy/Enhancer of Split-1) - GR (glucocorticoid receptor), and the stress-associated polarity signaling pathway. Under stress, there is a change in the functioning of these mechanisms, leading to an increase in the permeability of the intestinal wall. It results in translocation of bacteria from the lumen into the underlying layers which causes activation of the immune response with subsequent development of an inflammatory reaction. The presented data testify to the prospects and validity of the development of methods of correction of stress-induced shifts in the colon by influencing the central and local mechanisms of realization of the stress response and the state of the microbiota.

Decreased putamen activation in balancing goal-directed and habitual behavior in binge eating disorder

Acute stress is associated with a shift from goal-directed to habitual behavior. This stress-induced preference for habitual behavior has been suggested as a potential mechanism by which binge eating disorder (BED) patients succumb to eating large amounts of high-caloric foods in an uncontrolled manner (i.e., binge episodes). While in healthy subjects the balance between goal-directed and habitual behavior is subserved by the anterior cingulate cortex (ACC), insular cortex, orbitofrontal cortex (OFC), anterior caudate nucleus, and posterior putamen, the brain mechanism that underlies this (possibly amplified) stress-induced behavioral shift in BED patients is currently unknown. In the current study, 76 participants (38 BED, 38 healthy controls (HCs)) learned six stimulus-response-outcome associations in a well-established instrumental learning task. Subsequently, three outcomes were selectively devalued, after which participants underwent either a stress induction procedure (Maastricht Acute Stress Test; MAST) or a no-stress control procedure. Next, the balance between goal-directed and habitual behavior was assessed during functional magnetic resonance imaging. Findings show that the balance between goal-directed and habitual behavior was associated with activity in the ACC, insula, and OFC in no-stress HCs. Although stress and BED did not modulate the balance between goal-directed and habitual behavior, BED participants displayed a smaller difference in putamen activation between trials probing goal-directed and habitual behavior compared with HCs when using a ROI approach. We conclude that putamen activity differences between BED and HC could reflect changes in monitoring of response accuracy or reward value, albeit perhaps not sufficiently to induce a measurable shift from goal-directed to habitual behavior. Future research could clarify potential boundary conditions of stress-induced shifts in instrumental behavior in BED patients.

Влияние пептида His-Phe-Arg-Trp-Pro-Gly-Pro на процессы свободнорадикального окисления в условиях хронического иммобилизационного стресса

Studying the effects of regulatory peptides on the stress-induced shifts in the bodily processes is of great fundamental and applied significance. Currently, a wide range of peptide neurotropic drugs, affecting the stress response development, are used in medicine, and new promising molecules are being studied. The study was aimed to assess the effects of the adrenocorticotropic hormone (ACTH) synthetic analog, ACTH(6-9)-Pro-Gly-Pro, administered at a dose of 5, 50 and 500 μg/kg, on the free-radical oxidation processes in Wistar rats, subjected to chronic restraint stress (CRS) during two weeks. Serum levels of 8-oxo-2'-deoxyguanosine (8-OHdG) and superoxide dismutase 3 (SOD3) were assessed by enzyme immunoassay, and the levels of thiobarbituric acid reactive substances (TBARS) were assessed by fluorimetric method. CRS lead to the significant increase in the 8-OHdG levels by 18.4% (p = 0.01) and the decrease in the SOD3 levels by 14.3% (p = 0.01), however, it had no effect on the levels of TBARS. ACTH(6-9)-Pro-Gly-Pro, administered at a dose of 5 and 50 μg/kg, significantly decreased the levels of 8-OHdG by 19.8% (p = 0.03) and 30% (p = 0.001), respectively. Thus, it was found that CRS resulted in oxidative stress in animals. ACTH(6-9)-Pro-Gly-Pro administration at a dose of 5 and 50 μg/kg inhibits the stress-induced free-radical oxidation processes.