Undesirable Phenomenon Research Articles

Abuse Through Power and Control in Human Societies – Essence, Characteristics and Effects

Abstract The object of the present scientific theoretical study is the abuse of power and control as a socially undesirable phenomenon in human behaviour and in human communities. The article examines the topics of power abuse and violence in a social structure, regardless of whether it is the workplace or another human community, the phenomena of harassment, mobbing, bossing and aggression as are considered as counterproductive social human behaviours. The scientific methodology used is a combination of an etymological review of the considered phenomena of violence, harassment, mobbing, bossing and aggression, content analysis of the concepts of the considered phenomena, combined with a critical scientific review. In conclusion, the idea of psychological safety is presented, which refers to the belief that being oneself, expressing oneself and one’s positions is not only useful for a human group, organization, community but must be safe for the individual, emphasizing the creation of a safe surrounding environment.

Underlying mechanism of structural transformation between GaSb and GaAs response to intense electronic excitation

Ion irradiation of semiconductors has emerged as a promising approach for fabricating self-organized nanosystems with high atomic precision, despite often being accompanied by undesirable phenomena. Exploring the mechanisms underlying structural transformations is crucial for assessing nanostructure array types under complex irradiation environments. By quantitatively calculating the thermodynamically driven processes and analyzing the impact of intrinsic structural parameters, distinct structural transformations in response to intense electronic excitation are systematically investigated in gallium antimonide (GaSb) and gallium arsenide (GaAs) systems. In high-energy regimes, the nanofibers layer of GaSb exhibits intriguing structural discrepancy, characterized by partial nanofibers with coherent boundaries, interspersed nanopores accompanied by antisite defects and Ga precipitates, distinguishing to a series of discontinuous latent tracks that emerged within cylindrical trajectories in GaAs. Furthermore, significant diffusion behaviors of the nanohillocks are discovered in GaAs, with higher average roughness than GaSb, driven by the gradient stress distribution influenced by the free-surface effects. The deposition energy for melting phase formation, Gibbs free energy, and Ga diffusion coefficients contribute to the distinctive structural features, evidencing relatively stable morphological configurations and higher irradiation resistance in GaAs. Consequently, special optoelectronic properties associated with structural discrepancies facilitate the design and optimization of material functionalities by irradiation technologies.

Influence of twist ratio of twisted tape turbulator on thermal and second law efficiency of spiral tube

This study aims to determine the effects of a spirally coiled tube paired with a twisted tape turbulator. The tube was maintained at a constant wall temperature, and the flow was considered to be turbulent. Effect of different flow rates has been studied in which the Reynolds number was ranging between 6000 and 52,000. The Reynolds number and twist angle of twisted tape are the main variables whose influence has been assessed on the heat transfer characteristics. It was observed that the twisted tape may totally change the hydrodynamics behavior of fluid in the spiral tube affecting both pressure drop and heat transfer. As a result of adding twisted tape the pressure drop ratio raised from 1.88 to 2.19 and the Nusselt number raised from 1.03 to 1.115. In order to evaluate both the heat transfer enhancement as a desired phenomenon and the pressure drop as an undesired phenomenon, the performance evaluation criteria (PEC) has also been studied. The amount of 0.868 was the highest PEC amount achieved through this method which indicates that the method has positive effect in enhancing the heat transfer characteristics. In order to better evaluate the proposed method, the White-Shamsundar efficiency has also been evaluated which considers both of the first and second law of thermodynamics simultaneously and reports the data based on both efficiencies of the first and second laws of thermodynamics.

Control Strategy for Disc Coreless Permanent Magnet Synchronous Motor with LC Filter

The disc coreless permanent magnet synchronous motor has the advantages of a short axial size, high power density, and small volume. Due to the coreless structure, its inductance is very small, which results in a serious current ripple and an unacceptable torque ripple if driven from a conventional inverter. This can be solved by installing an LC filter between the inverter and the motor. However, an undesirable resonance phenomenon is induced by the LC filter. In this paper, a new capacitive current feedback active damping (CCFAD) strategy is proposed. Instead of current sensors in the capacitor branch, a state observer is introduced to estimate the capacitance current. The observer is designed with double sliding mode surfaces, which reduces the order of the system. Compared to conventional capacitive current feedback, no additional current sensors are required, reducing the system cost. Besides the resonant harmonics, the phase current contains obvious fifth and seventh harmonics due to the special plane structure of the rotor. The proportional-integral-resonance (PIR) controller, instead of the traditional PI controller, is designed to suppress lower order harmonics. The experiment results show that current ripples due to resonance and rotor structure are suppressed significantly.

An Active Control Method Based on the Study of Dynamic Characteristics of Integrated Electric Drive Systems

<div>Integrated electric drive systems are characterized by high power density, reliability, and controllability, making them increasingly prevalent in the realm of electric commercial vehicles. However, the direct coupling between the motor shaft and the transmission system has introduced a series of undesirable torsional vibration phenomena. To investigate the dynamic characteristics of electric drive systems in operation for electric commercial vehicles, a comprehensive modeling approach is employed. This modeling framework takes into account key factors such as gear backlash, structural flexibility, and electromagnetic spatiotemporal excitations. Based on this model, the influence of the electrical system on time-varying gear mesh stiffness, gear transmission error, bearing forces, and other factors is investigated. Building upon this foundation, the article proposes an approach for active harmonic voltage injection. This method effectively reduces torque fluctuations, decreases the amplitude and fluctuation of gear mesh stiffness and gear transmission error, lowers the vibration accelerations of each shaft, and enhances the reliability of the integrated electric drive system.</div>

Validation of hemispherectomy outcome prediction scale in treatment of medically intractable epilepsy

The Hemispherectomy Outcome Prediction Scale (HOPS) was developed to aid both clinicians and patients in determining the chance of success after hemispheric surgery for medically refractory epilepsy. The original study generating HOPS had a multi-institutional, large cohort format yielding near perfect patient stratification. Evidence suggests that methodologies utilized to create such predictive models, including cross-validation as well as stratification utilizing the same data employed for model generation, may be at risk of an undesirable modeling phenomenon known as overfitting. We posed the question of whether overfitting may be influencing HOPS results and aimed for preliminary evidence of external validation with parameters from patients at our institution not included in the original HOPS study. We found HOPS to stratify our limited post-operative cohort adequately. However, the likelihood of complete seizure freedom among the patients predicted by HOPS to be at greatest chance of success was ∼75 %, about 20 points lower than in the original HOPS cohort. This reduction in absolute chance of success predicted by HOPS may represent some degree of overfitting. It will be informative to aim for external validation of HOPS utilizing patient cohorts entirely separate from those used for model generation. External validation of HOPS and similar models could optimize realistic prediction of success after intervention.

Indirect hazard evaluation by the prediction of backbreak distance in the open pit mine using support vector regression and chicken swarm optimization

Backbreak is one of the undesirable phenomena in open-pit mines and causes several adverse hazards, such as lanslide, rock falling off and bench instability. Backbreak is influenced by many factors, such as rock properties, blasting design and local geology, so it is very difficult to assess and evaluate backbreak accurately. Therefore, controlling and accurate prediction of backbreak distance are crucial tasks to reduce hazards in open-pit mines. For this, soft computing-based techniques are considered to be an effective means, as they can integrate various sophisticated factors into a function to predict and evaluate backbreak distance. So, in this study, support vector regression (SVR) based techniques and three different types of bio-inspired meta-heuristic (BIMH) algorithms, such as chicken swarm optimization (CSO), whale optimization algorithm (WOA) and seagull optimization algorithm (SOA) are used to develop backbreak distance prediction models. The support vector regression is used as a regression tool and BIMH algorithms are used to optimize the hyper-parameters in the support vector regression. Four different types of evaluation metrics are utilized to assess the model performance, namely coefficient of determination (R2), mean square error (MSE), mean absolute error (MAE) and variance account for (VAF). An integrated evaluation system is adopted to provide overall performance for each backbreak prediction scenario. It can be indicated that CSO-SVR based backbreak prediction models can procure the best comprehensive performance and also show the best calculation efficiency. Detailed results include R2, VAF, MSE and MAE equal to 0.99475, 0.034, 99.477 and 0.1553 for a testing set and 0.97450, 0.1633, 97.466, and 0.1914 for a training set which can be said to be an excellent prediction result. By doing this, the hazard risk induced by backbreak can be indirectly assessed. In addition, it is also found that some superior performance can be obtained in some evaluation metrics compared with previous studies which utilized the same backbreak dataset for prediction.

Automated monitoring of insulation by ultraviolet imaging employing deep learning

The corona effect on the surface of electrical system equipment and components generally indicates undesirable phenomena that can lead to physical degradation of materials or even equipment failure. One of the most promising techniques for monitoring corona discharges is the use of specialized cameras for the detection of ultraviolet radiation. This paper introduces an innovative algorithm for classifying the criticality of insulation based on attributes extracted from videos recorded using an ultraviolet detection camera. The attributes extracted from each facula origin include maximum persistence, area, and the minimum distance between the facula origin and the insulation. To obtain this distance, a technique combining a deep convolutional neural network model with an adaptive segmentation thresholding method is proposed. To validate the proposed methodology, inspections were conducted at a 500 kV substation. A total of 96 videos were recorded, within which 99 facula origins were identified. The object detection model applied demonstrated an accuracy of 85.5 % in detecting insulation in images, based on a validation set comprising 1,985 images and 8,730 instances. The results of the classification showed that 72.7 % of the facula origins recorded originated from regions far from the insulation (mainly cables and corona rings). These results demonstrate that the distance between the insulation and the facula origin is an essential attribute for video analysis, providing context for recorded discharges and allowing differentiation between cases where ultraviolet radiation originates from insulation and those where discharge location is less critical.

Microstructural and profilometric analysis of thermally sprayed cylinder wall coatings

AbstractCylinder bore coatings are widely used in automotive internal combustion engines to replace cylinder liners. During the atmospheric plasma spraying process, the coatings are oxidized and controlled by the Si content of the steel powder used as the coating raw material. This phenomenon affects the technological process, the microstructure, and the properties of the formed coatings. The research aims to investigate how the Si content of two commercial grades of steel powder commonly used in industry affects the undesirable consequences observed in practice, such as clogging of powder nozzles or large variations in coating hardness. The analyses and industrial experiments show that increasing the Si content can contribute significantly to these undesirable phenomena.

A comparative study on the physical fitness of college students from different grades and majors in Jiangxi province.

Research to date has not provided a clear understanding of how different grades and majors affect the physical fitness of college students. It is postulated that there are significant disparities in physical health among college students of different grades and majors. The purpose of this study was to evidence these health disparities and to engage in an extensive analysis and discussion thereof. A sample of 8,772 (2,404 boys and 6,368 girls) Chinese college students from freshman to junior years, aged 17-22, including 12 different majors in four colleges, were recruited in Jiangxi Province. All seven physical fitness indicators (body mass index (BMI), forced vital capacity, 50-m dash, standing long jump, sit and reach, upper body muscle strength, and endurance runs) were conducted for all participants. One-way ANOVA and LSD tests were conducted to compare the physical fitness scores of different grades in the same major. Independent sample t-tests were utilized to compare the differences in every physical fitness indicator for different majors. Pearson's correlations among 12 majors for every grade were conducted to study the significant corrections between the two physical fitness indicators. The body mass index (BMI) and physical fitness indicator (PFI) for college students of different grade were investigated using a nonlinear regression model. The current state of physical fitness among college students is concerning, as the majority of students were barely passing (with a passing rate of 75.3%). Specifically, junior students exhibited lower scores than freshman and sophomore students across all 12 majors. From freshman to junior year, majors of music (78.01±4.58), English (79.29±5.03), and education (76.26±4.81) had the highest scores, respectively, but major art consistently scored the lowest, which were 73.85±6.02, 74.97±5.53, and 72.59±4.84, respectively. Pairwise comparisons revealed more significant differences in individual physical fitness indicators among the three grades in humanities than in sciences. Pearson's correlations showed significant correlations among seven physical fitness indicators in all three grades. PFI had a parabolic trend with BMI both for boy and girl college students in Jiangxi province. The physical fitness indicators of college students in Jiangxi province significantly differed in grades and majors, showing undesirable phenomena. The physical fitness of senior and humanities major college students was much weaker and needs sufficient attention. The relationship between BMI and PFI presented an inverted "U"-shaped change characteristic. Continued nationwide interventions are needed to promote physical activity and other healthy lifestyle behaviors in China.

Microflora of Secretions in a Surgical Hospital of Orthopedics and Traumatology Profile for 2021-2023 (SI “ITO NAMS of Ukraine”)

Summary. Healthcare-associated infections (HAIs), namely, surgical site infections, early postoperative and subsequent in-hospital infections, are the most common undesirable phenomenon in the world. According to statistics, at least one case of HAIs is diagnosed in every 100 hospitalized patients in hospitals of 7 developed and 15 other countries of the world at any given time. The occurrence of such complications during the treatment of a patient in a hospital leads to the need of additional diagnostic tests, additional courses of antibiotics, and unplanned surgical intervention. Worsening of the prognosis of treatment may occur due to the formation of the so-called resistant microflora in such patients, with a real probability of spreading the infection in the hospital. Prevention of HAIs in practice occurs through planned infection control in operating rooms and procedure rooms in clinical departments and qualified timely diagnostic work of certified microbiological laboratories in hospitals. Objective. The objective of the study was to determine the spectrum of microflora of secretions for three years (2021-2023) in orthopedic and trauma patients due to changes in modern injuries received more often because of military aggression and to propose the identified differences as criteria for prescribing antibacterial drugs in complex inpatient treatment. The work shows that over the past three years (2021-2023), the ratio of gram-positive and gram-negative microorganisms in the study material almost did not change and averaged 1.65. The peculiarity of the analyzed period was an increase in the number of methicillin-resistant staphylococci by 1.3 times. The spectrum of gram-negative clinical strains has changed, namely, the number of Kl.pneumoniae clinical strains with a high level of polyresistance has increased by 2.5 times. The obtained data made it possible to identify the spectrum of microflora of secretions in orthopedic and trauma patients with modern infectious complications, which prompts us to make changes in the standards of antibacterial treatment protocols, and to plan the needs for certain antibiotics in hospitals with personalization of their prescription to improve the effectiveness of treatment and reduce the risk of development of antimicrobial resistance.

Переходные участки бесстыкового пути, примыкающие к стрелочным переводам

Purpose: consider the problem of interaction between turnouts and adjacent sections of a seamless railway track. Methods: statistical data analysis. Results: an analysis of the results of domestic and foreign studies has been carried out, which show that in such areas there is a jump with subsequent extrusion of material of less rigidity and an increase in the slope of the elastic unevenness, i. e., an undesirable phenomenon occurs — a shock wave. The impact force depends on the mass of the rolling stock and the speed of movement, the geometric evenness of the rail track and the chosen approaches to designing the transition zone as a whole. Jump and mainly occurs due to compression and pushing out of structural layers and materials of lower rigidity in the under-rail area. The impact force depends on the mass of the rolling stock and the speed of movement, the geometric evenness of the rail track and the chosen approaches to designing the transition zone as a whole. Jump and mainly occurs due to compression and pushing out of structural layers and materials of lower rigidity in the under-rail area. Shock waves caused by uneven rigidity of sections have negative consequences (the appearance of deviations in level, subsidence, distortions, increased intensity of rail wear, the appearance of rail defects), which increase the cost of maintenance of the railway track. An analysis of the accumulation of residual deformations has been carried out, which shows the systematic formation of geometric irregularities in adjacent areas in the turnout area. Practical importance: from the point of view of the design of the transition zone, the expected advantage will be the differentiation of structural materials and elements and their influence on achieving the optimal gradation of railway track rigidity in the vertical and horizontal (transverse, longitudinal directions), selection of the optimal ratio of the mechanical properties of individual elements of the superstructure structure. It should also be noted that it is necessary to conduct an additional feasibility study of the feasibility of constructing transition sections in the area where the track and switches meet, taking into account the operational features of individual railway lines.

Impact of Admixtures on Segregation in Self-compacting concrete: A Comparative Study Between Standardized and Ultrasonic Pulse Velocity (UPV) Methods

Mastering the rheology of self-compacting concrete (SCC) remains a major challenge for researchers. One of the main obstacles is segregation, an undesirable phenomenon where aggregates separate from the matrix, thus compromising the quality and homogeneity of the material. This study aims to use the ultrasonic pulse velocity (UPV) measurement technique to evaluate the variation in the degree of static segregation in self-compacting concretes. To do so, column-type molds of different sizes were fabricated. The first was designed in accordance with the recommendations of standard V1, while the others, of different dimensions, were made according to standards V2 and V3. The latter allowed the study of the scale effect on the segregation of SCC, by comparing the results with those obtained using UPV. Five SCC mixes, containing respectively 1%, 1.2%, 1.4%, 1.6% and 1.8% of admixture, were tested using standard techniques (sieve and column test), then compared to the results obtained with the UPV method. The experimental results of the two methods were analyzed and compared to other tests, such as spread, L-box, and sieve stability. Moreover, the correlation between the results of the ultrasonic tests and those of the standardized tests (V1, V2, and V3) showed a high coefficient of determination R²: 86% for V1, 92% for V2 and 87% for V3. These results demonstrate that the UPV method is a promising alternative for evaluating segregation of fresh concrete.

A comprehensive review on freeze-induced deterioration of frozen egg yolks: Freezing behaviors, gelation mechanisms, and control techniques.

Over the years, the production of eggs has increased tremendously, with an estimated global egg production of 9.7 billion by 2050. Further processing of shell eggs to egg products has gained growing popularity. Liquid egg yolks, an innovative form of egg replacement, still suffer from short shelf-life issues, and freezing has been applied to maintain freshness. An undesirable phenomenon called "gelation" was found during the production of frozen egg yolks, which has attracted numerous scholars to study its mechanism and quality control methods. Therefore, we comprehensively reviewed the history of the studies on frozen egg yolks, including the production procedure, the fundamentals of freezing, the gelation mechanism, the factors affecting gelation behaviors, and the techniques to control the gelation behaviors of frozen egg yolks. Reporting the production procedure and freezing fundamentals of frozen egg yolks will give readers a better understanding of the science and technological aspects of frozen egg yolks. Furthermore, a comprehensive summary of the mechanism of egg yolk gel formation induced by freeze-thawing and relevant control techniques will provide insights to researchers and manufacturers in the field of frozen egg processing.

Offsetting Dense Particle Sedimentation in Microfluidic Systems.

Sedimentation is an undesirable phenomenon that complicates the design of microsystems that exploit dense microparticles as delivery tools, especially in biotechnological applications. It often informs the integration of continuous mixing modules, consequently impacting the system footprint, cost, and complexity. The impact of sedimentation is significantly worse in systems designed with the intent of particle metering or binary encapsulation in droplets. Circumventing this problem involves the unsatisfactory adoption of gel microparticles as an alternative. This paper presents two solutions-a hydrodynamic solution that changes the particle sedimentation trajectory relative to a flow-rate dependent resultant force, and induced hindered settling (i-HS), which exploits Richardson-Zaki (RZ) corrections of Stokes' law. The hydrodynamic solution was validated using a multi-well fluidic multiplexing and particle metering manifold. Computational image analysis of multiplex metering efficiency using this method showed an average reduction in well-to-well variation in particle concentration from 45% (Q = 1 mL/min, n = 32 total wells) to 17% (Q = 10 mL/min, n = 48 total wells). By exploiting a physical property (cloud point) of surfactants in the bead suspension in vials, the i-HS achieved a 58% reduction in the sedimentation rate. This effect results from the surfactant phase change, which increases the turbidity (transient increase in particle concentration), thereby exploiting the RZ theories. Both methods can be used independently or synergistically to eliminate bead settling in microsystems or to minimize particle sedimentation.

A numerical analysis of pressure characteristics in the deflector jet pilot stage valve with an innovative deflector deflection

Electric-hydraulic servo-valves are extensively used in the aerospace, mechanical, and aerodynamics industries to control missile wings or airplanes precisely. Aiming to reduce undesired flow phenomena inside the deflector jet pilot valve, innovative deflections of deflector are proposed in this paper. A numerical analysis is performed using STAR CCM + to investigate the pressure and flow characteristics inside the pilot stage of deflector jet servo-valve. For observing the pressure, cavitation and flow characteristics, the Eulerian multi-phase model, VOF phase interaction, and realizable k−ε model for the turbulent flow are used during numerical simulations. The supply and outlet pressure are kept at 24 MPa and 1 MPa, respectively. To verify the calculated numerical results for turbulent flows, the velocity distribution to the V-groove exit of the deflector jet pilot stage is calculated and discussed with the theoretical results. The numerically calculated results show good agreement with published analytical results. The result shows that by the innovative rotation of the deflector both in clockwise and anti-clockwise directions, significant pressure in the receivers is obtained than traditionally moving deflector to the left and right for the same supply pressure. Moreover, when the deflector is positioned clockwise or anti-clockwise by 5°, less cavitation is observed than in the traditional model. The key finding of this paper shows that innovative structural optimization of the amplifier disk and deflector is of utmost importance.

Exploring Volatile Profiles and De-Flavoring Strategies for Enhanced Acceptance of Lentil-Based Foods: A Review.

Lentils are marketed as dry seeds, fresh sprouts, flours, protein isolates, and concentrates used as ingredients in many traditional and innovative food products, including dairy and meat analogs. Appreciated for their nutritional and health benefits, lentil ingredients and food products may be affected by off-flavor notes described as "beany", "green", and "grassy", which can limit consumer acceptance. This narrative review delves into the volatile profiles of lentil ingredients and possible de-flavoring strategies, focusing on their effectiveness. Assuming that appropriate storage and processing are conducted, so as to prevent or limit undesired oxidative phenomena, several treatments are available: thermal (pre-cooking, roasting, and drying), non-thermal (high-pressure processing, alcohol washing, pH variation, and addition of adsorbents), and biotechnological (germination and fermentation), all of which are able to reduce the beany flavor. It appears that lentil is less studied than other legumes and more research should be conducted. Innovative technologies with great potential, such as high-pressure processing or the use of adsorbents, have been not been explored in detail or are still totally unexplored for lentil. In parallel, the development of lentil varieties with a low LOX and lipid content, as is currently in progress for soybean and pea, would significantly reduce off-flavor notes.

Study on the Reuse of Shield Mud from Clay Stratum in Synchronous Grouting Slurry

The purpose of this study is to investigate the feasibility of replacing the fly ash in synchronous grouting material by reusing the shield mud produced in the clay stratum during the shield construction of Wuhan Rail Transit Line 11. The test utilizes the shield mud from the clay stratum to replace the fly ash material in synchronous grouting at percentages of 20%, 40%, 60%, 80%, and 100%, and research and analyses are conducted on the fluidity, stability, strength, and resistance to water dispersion of the slurry after the replacement; at the same time, improvements in the undesirable phenomenon produced by the synchronous grouting slurry are also examined after the replacement. The results show that, when the fly ash is replaced by shield mud at 80%, the mortar still has good stability and strength performance, but, at the same time, the initial value of consistency and the phenomenon of flow time loss is too large. Through the adjustment of the water–binder ratio and the addition of an appropriate amount of a polycarboxylate superplasticizer agent, the adverse phenomenon of the slurry is effectively improved, and the compressive strength and ease of the slurry are also improved. At the same time, when adding an appropriate amount of hydroxyethyl methyl cellulose (HEMC), the slurry has good water dispersion resistance, but, with the gradual increase in HEMC, the fluidity of the slurry deteriorates and the compressive strength decreases. The test proves that the shield mud in the clay stratum can be used to replace most of the fly ash in an appropriate proportion, which not only solves the problem of the shield mud being difficult to work with, but also provides more valuable insights for tunneling projects.

High‐frequency digitally adaptive pulse skipping modulated voltage‐mode controlled quadratic buck converter

AbstractThe quadratic buck converter is renowned for its steep step‐down capability. It encounters increased losses due to its high component count. In scenarios with light loads, switching losses become the dominant factor. Additionally, the presence of two right‐half plane zeros impairs transient response, even at high‐frequency switching operations. Incorporating this converter into the digital domain introduces an undesired phenomenon known as subharmonic oscillation, rendering the system unstable, albeit potentially mitigated over time—a drawback particularly undesirable for converters tasked with rapid load dynamics. This paper introduces an adaptive pulse skipping modulation scheme to control metal–oxide–semiconductor field‐effect transistor (MOSFET) switching actions, enhancing overall efficiency in discontinuous conduction mode. Furthermore, the effects of right half‐plane (RHP) zeros on stability are analyzed within these switching schemes. The proposed scheme is integrated with voltage‐mode control. Simulation and theoretical analyses are conducted to validate this converter. A flat efficiency of 89%to 86%for the load range of 25 to 700 mA is obtained, outperforming other existing schemes. The results demonstrate that the adaptive pulse modulation scheme effectively improves efficiency and stability in discontinuous conduction mode converters. This research provides valuable insights for optimizing power electronics systems with varying load dynamics.

Dithiothreitol prevents the spontaneous release of cortical granules in in vitro aged mouse oocytes by protecting regulatory proteins of cortical granules exocytosis and thickening the cortical actin cytoskeleton

In assisted fertility protocols, in vitro culture conditions mimic physiological conditions to preserve gametes in the best conditions. After collection, oocytes are maintained in a culture medium inside the incubator until in vitro fertilization (IVF) is performed. This time outside natural and physiological conditions exposes oocytes to an oxidative stress that renders in vitro aging. It has been described that in vitro aging produces a spontaneous cortical granule (CG) release decreasing the fertilization rate of oocytes. Nevertheless, this undesirable phenomenon has not been investigated, let alone prevented. In this work, we characterized the spontaneous CG secretion in in vitro aged oocytes. Using immunofluorescence indirect, quantification, and functional assays, we showed that the expression of regulatory proteins of CG exocytosis was affected. Our results demonstrated that in vitro oocyte aging by 4 and 8 h altered the expression and localization of alpha-SNAP and reduced the expression of NSF and Complexin. These alterations were prevented by supplementing culture medium with dithiothreitol (DTT), which in addition to having a protective effect on those proteins, also had an unexpected effect on the actin cytoskeleton. Indeed, DTT addition thickened the cortical layer of fibrillar actin. Both DTT effects, together, prevented the spontaneous secretion of CG and recovered the IVF rate in in vitro aged oocytes. We propose the use of DTT in culture media to avoid the spontaneous CG secretion and to improve the success rate of IVF protocols in in vitro aged oocytes.