Passive Response Research Articles

Glial tone of aggression

Anger transition is often abrupt. In this study, we investigated the mechanisms responsible for switching and modulating aggression levels. The cerebellum is considered a center for motor coordination and learning; however, its connection to social behavior has long been observed. Here, we used the resident-intruder paradigm in male mice and examined local field potential (LFP) changes, glial cytosolic ion fluctuations, and vascular dynamics in the cerebellar vermis throughout various phases of a combat sequence. Notably, we observed the emergence of theta band oscillations in the LFP and sustained elevations in glial Ca2+ levels during combat breakups. When astrocytes, including Bergmann glial cells, were photoactivated using channelrhodopsin-2, the theta band emerged and an early combat breakup occurred. Within a single combat sequence, rapid alteration of offensive (fight) and passive (flight) responses were observed, which roughly correlated with decreases and increases in glial Ca2+, respectively. Neuron-glial interactions in the cerebellar vermis may play a role in adjusting Purkinje cell excitability and setting the tone of aggression. Future anger management strategies and clinical control of excessive aggression and violent behavior may be realized by developing a therapeutic strategy that adjusts glial activity in the cerebellum.

The interaction between neuromuscular forces, aerodynamic forces, and anatomical motion in the upper airway predicts the severity of pediatric OSA.

Upper airway neuromuscular response to air pressure during inhalation is an important factor in assessing pediatric subjects with obstructive sleep apnea (OSA). The neuromuscular response's strength, timing, and duration all contribute to the potential for airway collapses and the severity of OSA. This study quantifies these factors at the soft palate, tongue, and epiglottis to assess the relationship between neuromuscular control and OSA severity in 20 pediatric subjects with and without trisomy 21, under dexmedetomidine-induced sedation. The interaction between neuromuscular force and airflow pressure force was assessed based on power transferred between the airway wall and airflow calculated from airway wall motion (from cine magnetic resonance images) and air pressure acting on the airway wall (from computational fluid dynamics simulations). Airway wall motion could be asynchronous with pressure forces due to neuromuscular activation, or synchronous with pressure forces, indicating a passive response to airflow. The obstructive apnea-hypopnea index (oAHI) quantified OSA severity. During inhalation, the normalized work done through asynchronous dilation of the airway at the soft palate, tongue, and epiglottis correlated significantly with oAHI (Spearman's ρ = 0.54, 0.50, 0.64; P = 0.03, 0.03, 0.003). Synchronous collapse at the epiglottis correlated significantly with oAHI (ρ = 0.52; P = 0.02). Temporal order of synchronous and asynchronous epiglottis motion during inhalation predicted the severity of OSA (moderate vs. severe) with 100% sensitivity and 70% specificity. Subjects with severe OSA and/or trisomy 21 have insufficient neuromuscular activation during inhalation, leading to collapse and increased neuromuscular activation. Airflow-driven airway wall motion during late inhalation likely is the main determinant of OSA severity.NEW & NOTEWORTHY This is the first study that combines cine MRI and computational fluid dynamics with in vivo synchronous respiratory flow measurement to quantify the interaction between airway neuromuscular forces, aerodynamic forces, and airway anatomy noninvasively in pediatric patients with obstructive sleep apnea (OSA). The results indicate power transfer predicts OSA severity.

Parent-adolescent conflict: an exploration from the perspective of Vietnamese adolescents.

This research investigates parent-adolescent conflicts from the viewpoint of Vietnamese adolescents. Employing a mixed-method approach, the study conducted in-depth interviews and a questionnaire survey with 706 high-school students. The findings highlight that conflicts between Vietnamese parents and adolescents commonly arise regarding internet usage for entertainment and academic purposes. Furthermore, adolescents reported having more conflicts with their mothers than with their fathers. Although instances of parental aggression were identified, most adolescents perceived their parents' conflict resolution as supportive. However, Vietnamese adolescents tended to display passive behavioral responses during conflicts. The research also identified certain emotional responses as warning signs of mental health issues, including suicidal thoughts, among some adolescents. Moreover, a higher frequency of conflicts with parents was significantly associated with increased peer connections. The study emphasizes the importance of professionals, such as school social workers or counselors, prioritizing the understanding of parent-child conflicts' impact on adolescents' emotions and mental health. Additionally, it underscores the significance of examining parenting patterns and parent-child communication within contemporary Vietnamese families.

Abstract 15900: Probing Mitochondrial Dysfunction in Mouse Hearts With Doxorubicin-Induced Cardiotoxicity Using Ungated 4D Oxy-Wavelet MRI

Introduction: Despite advances in cancer therapy greatly improving patient survival, more than two-thirds of cancer survivors will still face serious life-threatening cardiomyopathy caused by anti-cancer anthracyclines. Doxorubicin (Dox), a well-known, well studied anthracycline, is a major cause for long-term morbidity and mortality among cancer survivors. Pertinent to this issue is the lack of non-invasive imaging tools that can detect DOX induced cardiomyopathy before irreversible tissue damage is done. Current research of cellular mechanisms underlying DOX-induced cardiotoxicity has shown that mitochondrial dysfunction are central to this cardiomyopathy. Hypothesis: We hypothesize that this mitochondrial dysfunction precedes clinical changes in cardiac strain and left-ventricle ejection fraction. Methods: To probe mitochondrial function non-invasively, we use motion-and-time resolved 4D functional MRI, coined 4D Oxy-Wavelet. Our methodology can capture dynamic changes in the blood oxygenation level dependent (BOLD) signal with high spatiotemporal resolution. Our cyclic hypoxia challenge leverages the need for in-tact mitochondrial function to maintain homeostatic oxygenation during hypoxia. We combine our 4D-fMRI methodology with a cyclic hypoxia challenge to stress-test the mitochondria in a mouse model of DOX-induced cardiotoxicity. We use a novel time-frequency analysis of the event-driven BOLD response to automate the detection of mitochondrial dysfunction in-vivo. Results: C57BL6/J were given Dox over the course of one week. 4D oxy-wavelet MRI was performed at baseline, day 1, 3, 4, and 7 to evaluate the ability to rapidly detect acute DOX induced cardiotoxicity. We found that as early as day one post exposure, mice exhibited a passive response to the hypoxia challenge, representing an inability to maintain homeostatic oxygen and underlying mitochondria dysfunction, that was maintained through this acute period.

The in vivo passive stretch response of the pectoralis major is region-specific

The pectoralis major (PM) is a broad muscle commonly divided into three regions, which contribute uniquely to shoulder stability and movement. The PM muscle regions likely respond differently to stretch, but this has never been shown in vivo. We used shear wave elastography to assess the stretch response of different PM muscle regions during shoulder abduction and external rotation in 20 healthy male participants. Participants’ shoulder was passively rotated through their range of motion in 5.7° increments and shear wave velocities (SWV) were obtained for each muscle region. A piece-wise model was fitted to the SWV-joint angle data, from which slack angle, slack stiffness and elasticity coefficient were determined. For shoulder abduction, we found that the sternocostal region had a significantly smaller slack angle (p = 0.049) and greater slack stiffness (p = 0.005) than the abdominal region, but there was no difference for elasticity coefficient (p = 0.074). For external rotation, only slack stiffness was greater for the sternocostal than the abdominal region (p < 0.001) with no differences found for slack angle (p = 0.18) and elasticity coefficient (p = 0.74). However, our data indicates that neither region was slack in this condition. These findings indicate that the sternocostal and abdominal regions respond differently to passive stretch, highlighting the PM’s functional differentiation. This differentiation should be considered during treatment interventions such as PM muscle harvesting or treatments for breast cancer.

Supporting teachers to actively respond to bullying and to build positive relationships with their students: effects of the T-SUPPORT training.

Despite the central role that teachers can have in preventing and reducing bullying, they often feel insecure about how to deal with bullying. This study evaluated a short teacher training - called the Teachers SUPporting POsitive RelaTionships (T-SUPPORT) training - that aims to reduce bullying by supporting teachers in building positive teacher-student relationships and in actively dealing with bullying. The aim of the current study was to investigate whether the T-SUPPORT training resulted in higher quality teacher-student relationships, and more active and less passive responses to bullying incidents, and whether these improvements in turn resulted in lower levels of bullying victimization. In a Randomized Controlled Trial 10 Belgian primary schools were randomly assigned to an intervention or control condition. The Grades 4-6 teachers of the five schools in the intervention condition received the three-session school-based training; control teachers received no intervention. Grade 4-6 students (N = 964; 55 classrooms) in these schools completed questionnaires at pre- and post-test. In contrast to the hypotheses, results of the two-level linear mixed model analyses revealed no significant effect of the training on teacher-student relationship quality, teachers' responses to bullying and bullying victimization. Yet, higher quality teacher-student relationships and more active teacher responses to bullying were significantly associated with less bullying victimization, whereas more passive responses were linked with more victimization. The latter findings are in line with theorizing and research on the role that teachers can play in reducing bullying.

Role of the rostral dorsomedial column of the periaqueductal gray during social defeat in rats.

Previous studies showed that the dorsal premammillary nucleus of the hypothalamus (PMD) is involved in social passive defensive behaviors likely to be meditated by descending projections to the periaqueductal gray (PAG). We focused on the rostral dorsomedial PAG (rPAGdm) to reveal its putative neural mechanisms involved in mediating social defensive responses. By combining retrograde tracing and FOS expression analysis, we showed that in addition to the PMD, the rPAGdm is influenced by several brain sites active during social defeat. Next, we found that cytotoxic lesions of the rPAGdm drastically reduced passive defense and did not affect active defensive responses. We then examined the rPAGdm's projection pattern and found that the PAGdm projections are mostly restricted to midbrain sites, including the precommissural nucleus, different columns of the PAG, and the cuneiform nucleus (CUN). Also, we found decreased FOS expression in the caudal PAGdm, CUN, and PMD after the rPAGdm was lesioned. The results support that the rPAGdm mediates passive social defensive responses through ascending paths to prosencephalic circuits likely mediated by the CUN. This study provides further support for the role of the PAG in the modulation of behavioral responses by working as a unique hub for influencing prosencephalic sites during the mediation of aversive responses.

Increased intracellular diffusivity of macromolecules within a mammalian cell by low-intensity pulsed ultrasound

Whilst a number of studies have demonstrated that low-intensity pulsed ultrasound (LIPUS) is a promising therapeutic ultrasound technique that can be used for delivering mild mechanical stimuli to target tissue non-invasively, the underlying biophysical mechanisms still remain unclear. Most mechanism studies have focused explicitly on the effects of LIPUS on the cell membrane and mechanosensitive receptors. In the present study, we propose an additional mechanism by which LIPUS propagation through living cells may directly impact intracellular dynamics, particularly the diffusion transport of biomolecules. To support our hypothesis, human epithelial-like cells (SaOS-2 and HeLa) seeded on a confocal dish placed on a microscope stage were exposed to LIPUS with various exposure conditions (ultrasound frequencies of 0.5, 1 and 3 MHz, peak acoustic pressure of 200 and 400 kPa, a pulse repetition frequency of 1 kHz and a 20 % duty cycle), and the diffusivities of various sizes of biomolecules in the cytoplasm area were measured using fluorescence recovery after photobleaching (FRAP). Furthermore, giant unilamellar vesicles (GUVs) filled with macromolecules were used to examine the physical causal relationship between LIPUS and molecular diffusion changes. Nucleocytoplasmic transport coefficients were also measured by modified FRAP that bleaches the whole cell nuclear region. Extracellular signal-regulated kinases (ERK) activity (the phosphorylation dynamics) was monitored using fluorescence resonance energy transfer (FRET) microscopy. All the measurements were taken during, before and after the LIPUS exposure. Our experimental results clearly showed that the diffusion coefficients of macromolecules within the cell increased with acoustic pressure by 12.1 to 33.5 % during the sonication, and the increments were proportional to their molecular sizes regardless of the ultrasound frequency used. This observation in living cells was consistent with the GUVs exposed to the LIPUS, which indicated that the diffusivity increase was a passive physical response to the acoustic energy of LIPUS. Under the 1 MHz LIPUS exposure with 400 kPa, the passive nucleocytoplasmic transport of enhanced green fluorescent protein (EGFP) was accelerated by 21.4 %. With the same LIPUS exposure condition, both the diffusivity and phosphorylation of ERK induced by EGF treatment were significantly elevated simultaneously, which implied that LIPUS could also modify the kinase kinetics in the signal transduction process. Taken together, this study is the first attempt to uncover the physical link between LIPUS and the dynamics of intracellular macromolecules and related biological processes that LIPUS can possibly increase the diffusivity of intracellular macromolecules, leading to the changes in the basic cellular processes: passive nucleocytoplasmic transport and ERK. Our findings can provide a novel perspective that the mechanotransduction process that the intracellular region, in addition to the cell membrane, can convert the acoustic stimuli of LIPUS to biochemical signals.

Sex differences in avoidance behavior and cued threat memory dynamics in mice: Interactions between estrous cycle and genetic background

Anxiety disorders are the most prevalent mental illnesses worldwide, exhibit high heritability, and affect twice as many women as men. To evaluate potential interactions between genetic background and cycling ovarian hormones on sex differences in susceptibility to negative valence behaviors relevant to anxiety disorders, we assayed avoidance behavior and cued threat memory dynamics in gonadally-intact adult male and female mice across four common inbred mouse strains: C57Bl/6J, 129S1/SVlmJ, DBA/2J, and BALB/cJ. Independent of sex, C57Bl/6J mice exhibited low avoidance but high threat memory, 129S1/SvlmJ mice high avoidance and high threat memory, DBA/2J mice low avoidance and low threat memory, and BALB/cJ mice high avoidance but low threat memory. Within-strain comparisons revealed reduced avoidance behavior in the high hormone phase of the estrous cycle (proestrus) compared to all other estrous phases in all strains except DBA/2J, which did not exhibit cycle-dependent behavioral fluctuations. Robust and opposing sex differences in threat conditioning and extinction training were found in the C57Bl/6J and 129S1/SvlmJ lines, whereas no sex differences were observed in the DBA/2J or BALB/cJ lines. C57Bl/6J males exhibited enhanced acute threat memory, whereas 129S1/SvlmJ females exhibited enhanced sustained threat memory, compared to their sex-matched littermates. These effects were not mediated by estrous cycle stage or sex differences in active versus passive defensive behavioral responses. Our data demonstrate that core features of behavioral endophenotypes relevant to anxiety disorders, such as avoidance and threat memory, are genetically driven yet dissociable and can be influenced further by cycling ovarian hormones.

Compensating balance and loan bargaining power in China

AbstractChinese firms simultaneously have high levels of loans and cash holdings. Through listed firms on the Shanghai and Shenzhen Stock Exchanges, we establish a negative link between cash holdings and a firm's loan bargaining power, especially in regions with less bank competition, through a firm's passive response to bank requests rather than its voluntary excess cash reserves. Furthermore, state ownership, collateral, economic contribution, and reduced information asymmetry may effectively strengthen firm bargaining power and moderate the link. However, better marketisation strengthens the link. The banking sector may need to improve its efficiency through better credit rationing in future reforms.

Policy Analysis of China's Principal Rank System for Primary and Secondary Schools : Policies, Challenges, and Future Directions

The Principal Rank System for primary and secondary schools has undergone a nearly 30-year pilot phase, representing a significant reform in the realm of education management in China. However, challenges persist in advancing this reform, and the overall progress has been sluggish. This paper conducts a literature-based examination of the policy background and the implementation of the Principal Rank System. During the promotion of this reform, the implementation of the Principal Rank System encounters multiple challenges, including passive responses from certain principals, inquiries into the determination of principal professional ranks, and the varied impacts of the salary incentive mechanism. This paper analyzes these issues and proposes solutions to address them. It is imperative to establish a unified and stringent principal admission system, develop a comprehensive principal evaluation framework, modernize the principal training mechanism, set forth a rational principal ranking system, enhance the principal duty station exchange system, address income disparities among regions, and augment feedback mechanisms following expert reviews to foster holistic educational development.

Enzyme-free, metal oxide-based amperometric-colorimetric dual-mode functional glucose sensor

To address the urgent need for glucose level detection in the human body, several affordable, lightweight, and skin-mounted glucose sensors have been developed. Enzymatic sensors are frequently utilized, but they have challenges of enzyme degradation and indirect charge transfer through a redox mediator, which affect their reusability and shelf life. Here, enzyme-free nickel oxide thin film electrode in an alkaline medium is used to enable direct charge transfer with glucose. A chemical reaction between glucose and the electrode surface occurs, leading to an additional oxidation (Ni+2/Ni+3) of the electrode under external bias. Additionally, the colorimetric analysis further validated this reaction through the transformation of a dark-colored NiO (Ni+3) electrode into a bleached color state (reduced from Ni+3 to Ni+2) through the oxidation of glucose. As the glucose concentrations increase to 5 mM, the color of the electrode is no longer optically readable (ΔT% ∼ 66%). The corresponding amperometric response is determined with a detection limit of 2 μM and a 3579 μA mM−1 cm−2 sensitivity, and it also recognizes a passive response to other interfering species and facilitates its one-month shelf life. Additionally, a two-electrode electrochemical colorimetric liquid cell-type glucose sensor has been designed to pave the way for future applications.

THE ANEURISMAL ABDOMINAL AORTA WALL MECHANICAL RESISTANCE LOSS AND COLLAGEN FIBRE PATHOLOGICAL REORIENTATION. A NUMERICAL STUDY

The biomechanical properties’ changes of the abdominal aortic aneurysms’ (AAA) walls are closely related to the pathological degeneration of the smooth muscle cells and the main fibrous components (collagen and elastin). In this study, the passive mechanical response of the aneurysmal aortic wall is computationally investigated as a function of the dispersion and orientation of collagen. So, to better understand how the ultimate resistance of the diseased wall varies, several numerical simulations on models of AAA specimens have been performed, using the Gasser-Ogden-Holzapfel anisotropic hyperplastic constitutive model where the dispersion and orientation parameters are explicitly introduced. The simulations were carried out for a variation of the average orientation of the collagen from 0° to 90° with a dispersion that varies from 0 (orthotropic case) to 1/3 (isotropic case). The results of the numerical simulations show that an increase in the dispersion and the angle of orientation in the aneurysm leads to a decrease in the circumferential resistance of the diseased artery. Such results can help to better understand the negative effects of the disease on the arterial wall and to target the necessary therapy.

What happens with the host during reshoring? An exploration of the host company's response in China

PurposeResearch studies on offshoring and reshoring have predominantly focused on the home company, widely ignoring the offshored company in the host country. The host company's influence and contribution have been unseen. This research explores how the host company responds to the home company's location decisions to maintain the dyadic relationship.Design/methodology/approachAn exploratory case study in China was conducted to examine the host company's response to reshoring. The case company has two Japanese parent companies that acted for the emergence of reshoring drivers. Primary and secondary data were collected and analysed through thematic analysis. The host company's response strategies to the home company's relocation decisions were identified and explored.FindingsThe findings reveal that four strategies, identified here as being cost control, market expansion, knowledge seeking and relationship bonding, were implemented by the host company. The importance of Industry 4.0 (I4.0) and knowledge transfer is also emphasised within these strategies.Practical implicationsThis research identified active and practical strategies conducted by the host company to maintain a cooperative relationship with the home company(ies). Instead of encountering a passive response from the host company, the home company may consider working with the host to overcome difficulties caused by emerging reshoring drivers and create an outcome beneficial to both.Originality/valueTo the authors’ knowledge, this is the first research to study manufacturing reshoring from the perspective of the host company. It provides a new perspective to understanding this phenomenon.

Data-Augmentation-Enabled Continuous User Authentication via Passive Vibration Response

Continuous identity authentication is critical for privacy protection throughout an entire user login session. In this paper, we propose a continuous user authentication mechanism namely, which employs the vibration responses from hand biometrics and is passively activated by natural user-device interaction. Hand vibration responses are embedded in the mechanical vibration of a force-bearing body consisting of one mobile device and one user hand. A built-in accelerometer of the device can capture hand-dependent vibration signals. Considering the concealment of vibration generation and the non-replicability of hand structure, it’s difficult for attackers to counterfeit user identity. Moreover, for ensuring the robustness of authentication performance to tapping behavior interference, we construct a data augmentation module jointly leveraging a signal processing and learning-based pipeline. It can generate enough vibration responses representing hand structure biometrics under various behaviors, thereby making comprehensively understand vibration response variation. We prototype on smartphones, and extensive experiments demonstrate that can achieve satisfactory authentication accuracy.

Digital governance with smart sensors: exploring grid administration in Zhejiang’s “Future Community”

Abstract This study explored sensor-based e-government practices in eight pilot “Future Communities” in Zhejiang Province, China. Adopting the approach of “e-government in everyday practice,” it examines how grid members at the grassroots level make sense of smart sensors and their mediated governance through the parameters of passive response, collaborative human and nonhuman networks, and calculability. In an emerging sensing environment, grid members are exposed to contradictory governance regimes, experimenting with and performing competing sets of discourses and actions that are either efficient or inefficient, manual or automatic, and progressive or regressive. Neither facilitated nor emptied by sensor-enabled Weberian functions, they actively improvise along with the dynamism of specific local interactions and situations. However, currently sensors and attendant technologies merely leave space for them to engage in ambiguities and negotiations concerning the extent and boundaries of technical solutionism rather than opening up possibilities for empowerment to refine the forms of governance.

A 3D multi-scale skeletal muscle model to predict active and passive responses. Application to intra-abdominal pressure prediction

Computational models have been used extensively to study the behavior of skeletal muscle structures, however few of these models are able to evaluate their 3D active response using as input experimental measurements such as electromyography. Hence, improving the activation mechanisms in simulation models can provide interesting and useful achievements in this field. Therefore, the purpose of this paper was to develop a multi-scale chemo-mechanical material model to consider the active behavior of skeletal muscle in 3D geometries. The model was used to investigate the response of abdominal muscles which represent a challenging scenario due to their complex geometry and anatomical conditions. Realistic muscle geometries and other tissues of the human abdomen, including transverse abdominis (TA), internal oblique (IO), external oblique (EO), rectus abdominis (RA), rectus sheath (RSH), linea alba (LA) and aponeurosis (APO) were considered. Since the geometry of these tissues was obtained from magnetic resonance images, an iterative algorithm was implemented to find the initial stress state that achieve the equilibrium of them with the intra-abdominal pressure. In order to investigate the functionality of the proposed model, the increase of intra-abdominal pressure was calculated during cough in the supine position while the Ca2+ signal for activating the muscles was set in regard to experimentally recorded electrical activity from previous studies. The amount of intra-abdominal pressure calculated by the model is consistent with reported experimental results. This model can serve as a virtual laboratory to analyze the role of the abdominal wall components in different conditions, such as the performance of meshes used for repairing hernia defects.

Rumor detection on social networks focusing on endogenous psychological motivation

Emerging information acquisition methods represented by social networks are increasingly popular. The freedom and concealment make social media become the main platform for rumor spreading. Rumor detection has attracted the attention of both academia and industry, and a series of rumor detection methods have emerged. However, existing methods focus on modeling exogenous features such as text content and user characteristics, while ignoring the endogenous psychological motivation of users. Sociological and psychological researches on rumor have demonstrated the correlation between the endogenous psychology of users and their behavior in social networks. Therefore, this study focuses on the intrinsic psychological motivation of users, probes the psychological changes of users after they are exposed to rumors from the perspectives of active sharing and passive response, analyzes and judges user behaviors to explore an efficient rumor detection method. Among them, active sharing behavior is based on the investigation of social users’ motivation, decision making and goal setting, and is related to users’ motivation to actively participate in content by creating posts and so on. Passive response, which is closely related to personal emotions originating from the influence of external factors, is a study of users’ cognitive processes and is associated with the way they handle information without active participation. Experiments demonstrate the superiority of our proposed method in rumor detection tasks, improving accuracy by 2.1% over the current baseline on the Twitter16 dataset and enabling early detection of rumors as they emerge.

Biomechanics of Chondrocytes and Chondrons in Healthy Conditions and Osteoarthritis: A Review of the Mechanical Characterisations at the Microscale.

Biomechanical studies are expanding across a variety of fields, from biomedicine to biomedical engineering. From the molecular to the system level, mechanical stimuli are crucial regulators of the development of organs and tissues, their growth and related processes such as remodelling, regeneration or disease. When dealing with cell mechanics, various experimental techniques have been developed to analyse the passive response of cells; however, cell variability and the extraction process, complex experimental procedures and different models and assumptions may affect the resulting mechanical properties. For these purposes, this review was aimed at collecting the available literature focused on experimental chondrocyte and chondron biomechanics with direct connection to their biochemical functions and activities, in order to point out important information regarding the planning of an experimental test or a comparison with the available results. In particular, this review highlighted (i) the most common experimental techniques used, (ii) the results and models adopted by different authors, (iii) a critical perspective on features that could affect the results and finally (iv) the quantification of structural and mechanical changes due to a degenerative pathology such as osteoarthritis.

AFM methods for studying the morphology and micromechanical properties of the membrane of human buccal epithelium cell

Using AFM methods in air under normal conditions in a wide range of local force effects ({F}_{const}< 40 μN) the relief, functional micromechanical properties (elasticity coefficient K, Young’s modulus E, elastic {Delta h}_{dfrm} and plastic {Delta h}_{stiff} deformations) and adhesive properties (work A of adhesive forces {F}_{adh}={F}_{adh}(x;y)) of the membranes of living adult cells of human buccal epithelium were studied in the presence of a protective layer < 100 nm of buffer solution that prevented the cells from drying. Almost all geometric and functional characteristics of the membrane in the local approximation at the micro- and nanolevels are affected by size effects and obey the laws of fractal geometry. The Brownian multifractal relief of the membrane is characterized by dimension {D}_{f} < 2.56 and irregularities < 500 nm vertically and < 2 μm horizontally. Its response to elastic (≤ 6 nN), active (6–21 nN), or passive (> 21 nN) stimulation ({F}_{const}) is a non-trivial selective process and exhibits a correspondingly elastic (K= 67.4 N/m), active (K= 80.2 N/m) and passive (K= 84.5 N/m) responses. K=K({F}_{const}) and E=E({F}_{const}) depend on {F}_{const}. Having undergone slight plastic deformations {Delta h}_{stiff} < 300 nm, the membrane is capable of restoring its shape. We mapped (E=E(x;y), {D}_{f} = 2.56; {Delta h}_{dfrm}={Delta h}_{dfrm}(x;y), {D}_{f} = 2.68; {Delta h}_{stiff}={Delta h}_{stiff}(x;y), {D}_{f } = 2.42, A=Aleft(x;yright) and {F}_{adh}={F}_{adh}(x;y)) indicating its complex cavernous structure.