Connective Elements Research Articles

New connective tissue structure of the wrist area - research on fetal material.

The correct function of the upper limb depends on the cooperation and coordination of the muscular and skeletal systems as well as the connective tissue elements present in it. Connective tissue forms fascia, connective tissue membranes and ligaments. Connective tissue mostly develops from the mesenchyme. It is formed from the intercellular substance consisting of protein fibrous elements and the ground substance. The fibrous elements generally fulfill the mechanical function of the intercellular substance. There are three types of fibrous elements: collagen fibers, reticular fibers and elastic fibers. The aim of the study was to examine the occurrence of fibrous structures in the wrist area in fetal material stored in the Prenatal Laboratory of the Department of Anatomy of the Wroclaw Medical University (Wroclaw, Poland). The research included 114 fetuses (53 male and 61 female) of between 117.0 and 197.0 (median 177.0) days of fetal life. The study showed 100% prevalence of a ring-shaped connective tissue structure on the radial side of the wrist located around the tendon of the "flexor carpi radialis muscle", previously unobserved in fetuses. Its bilaterality was found in 57.9% and unilaterality in 42.1% of the examined fetuses. In male fetuses, the ring-shaped structure was located in the right upper limb in 68.9% of the examined limbs, and in the left in 80.3%. Bilaterality was 49.2%, and unilaterality 50.8%. In female fetuses, this structure was observed in the right limbs in 84.9%, and in the left in 77.4%. Bilaterality was 61.1%, and unilaterality 38.9%. The structure that was observed has not been described in fetuses so far; only in one study authors describing a similar change in adults calls it an "Annular Pulley" and connects its significance with the system of disc-shaped ligaments of the tendons of the flexor muscles of the hand, which are an element of the attachment system of tendons to the skeletal system. Its function within the ligamentous and retinacular system of the wrist remains unknown. This is the first study to describe the occurrence of the "AP" in fetal material. Further research is required to understand its role in the biomechanics of the upper limb and its histological structure.

Leveraging digital connectivity for innovation performance: a fsQCA study on Chinese high-tech manufacturing firms

The digital connectivity view (DCV) represents a distinct strategic framework for understanding how firms leverage interconnected digital technologies to create sustainable competitive advantages in global markets. While digital connectivity promises enhanced innovation performance, organizations face significant challenges in effectively leveraging these capabilities, with outcomes remaining highly uneven across industries. This study examines how different configurations of digital connectivity elements and organizational capabilities drive innovation performance in manufacturing firms through an integrated theoretical framework combining dynamic capabilities theory and DCV. Using fuzzy-set qualitative comparative analysis of 63 Chinese high-tech manufacturing firms, the research identifies multiple distinct pathways to high innovation performance. The findings reveal four key mechanisms that explain how firms effectively leverage digital connectivity, with digital-architecture resources playing a central role. Different capability configurations produce varying levels of radical and incremental innovation outcomes. The research advances innovation management literature by empirically validating configurational patterns, developing a novel theoretical framework bridging DCV with dynamic capabilities theory, and providing practical insights for manufacturing firms in emerging economies navigating global crises while maintaining innovation vitality.

Retinal Nerve Fiber Layer Thickness(RNFL) Measurements in Nepalese Population of Eastern Region by Optical Coherence Tomography

Introduction: Glaucoma represents a group of disease defined by consistent remodeling of the connective tissue elements of the optic nerve head and with the loss of neural tissue of the retinal nerve fiber layer associated with the eventual development of distinctive patterns of visual function.1 OCT is used commonly to evaluate thinning of peripapillary retinal nerve fiber layer (RNFL) objectively and quantitatively, which is a hallmark for the diagnosis of glaucoma.2 As the OCT, normal database is commercially not available for Nepalese eyes. These measurements will provide a reference for the comparison and further evaluation of results of glaucoma and other patients with the help of OCT in the Nepalese Population. Methods: 384 eyes of normal population RNFL thickness measurements were done with peripapillary SD-OCT (Cirrus HD OCT Model 5000/500; Carl Zeiss Meditec, Dublin, USA). Multiple regression analyses were applied to assess the effect of age and mean refractive error on peripapillary RNFL thickness. Results: The average Retinal nerve fiber layer thickness (RNFLT) was highest in the age group 70-79 years (102.33 ±4.61µm) followed by age groups 50-59 years (93.89 ±5.89 µm) and 60-69 years (92.95 ±7.83 µm) respectively. The mean ± SD peripapillary RNFLT (µm) at the superior, inferior, nasal and temporal quadrants in the study population were 117.95±9.41µm, 120.71 ± 10.12 µm, 71.64 ±71.64 µm and 61.65±6.65µm respectively. Conclusion: This study may serve as a reference in comparing changes in RNFL thickness during glaucoma screening with SD-OCT in this population.

Design and Application of a Gripping Apparatus for Torsion Testing of Aluminum/Composite Tubes

As is known, hybrid composite shafts with fibers and metals offer remarkable improvements in terms of mechanical performance, and research is still ongoing in this field. Due to the nature of torsional loading, it is seen that various holding apparatuses are applied for specimens of different diameters to test the specimen without slipping between the test jaws, especially for large parts. This study examines specimen types and connection elements used in torque tests, and a practical solution that can be used in universal testing machines is investigated. In this context, experiments were carried out for unreinforced aluminum tubes and [±452/Al] arrayed specimens using screw clamp connection and shape-bonded designs. It was found that reinforcement of the clamping region of the specimens with an additional layer in hybrid tubes is a preferable solution for shape-bonded connections

Students’ Perception of The Use of Duolinggo for Learning English

This study aims to determine the perception of students majoring in English towards the use of the Duolingo for learning English and to find out which aspects of language improve after using the Duolingo for learning English. The population were 10 English Education Department students who had used or were currently using Duolingo. This research used quantitative method. In collecting the data, this research used a questionnaire. The results of this research showed that most students liked and enjoyed using the Duolingo application for learning English. The students were asked questions regarding their perceptions of Duolingo, particularly about the elements of utility, content, context, control, and connectivity or mobility, and almost all agreed that they liked the Duolingo app because various aspects of it aligned with these five elements. Moreover, most students agreed that Duolingo helped them improve some aspects of their English skills, such as improving their pronunciation, writing, listening, speaking, and vocabulary. Based on the results, it can be concluded that the majority of students have a positive perception of using the Duolingo app for learning English.

Съвременен атомистичен модел на изкуството. Част трета

The Contemporary Atomistic Model of Art sought represents an ontogenetic process of creation, communication and perception of the artwork in the environment that surrounds us and that is within us. Instead of immutable wholes (holism), we have infinite sets of processes of connection and disconnection, merging and splitting of “nuclei” (atomism) where interactions are clearly visible. Through art, thought of as the porous structure of society with permeable sites of relation, each image and each material form of an artwork is only a connective element with values and other forms that are transferable in society. This is a principle of dynamic connection in which form is a kind of representation and a potential condition of exchange. The in-between zone has been distinguished, bearing its own traditions and recognizing both the connectedness as well as the separate items that are connected. Fluid culture atomism (fluid atomism) is where we observe the dynamics in interactions in an ever-changing structure that is itself made up of separated atomic units briefly grouped into more complex molecular formations, with all the connections between them being impermanent and temporary. Both the internal structures and the state of the whole change. The interactions of individual units are a key factor in the analysis of processes in art. These processes are embedded in perishable, dynamically transforming networks of ‘private’ art worlds, the sum of which is not the Universal World but a momentary state in an ever-changing system. The relationship between the individual artist and the overall system of organized artistic life passes through interactions of a socialpsychological type in organized temporary groups of artists. This article discusses the possible relations between the field of social psychology and art. Emphasis is placed on the aspects of innovative artistic inquiry, discussed as the singular and the unique in art as opposed to the established order. Innovation in art is juxtaposed with innovation in social bonding as a social psychological problem of creativity. Individual creativity is compared to the creativity of groups and the particularities of the creative processes inherent to individual artists. Such an interpretation develops further the idea of an art world seen as impermanent and dynamically changing networks of ‘private’ art worlds. Among the autonomous zones defined by the individual and the group are found shared zones through which polar differences are harmonized. Individual artistic innovation is juxtaposed with innovative practices that are formed through the action of the groups.

Structural Deterioration and Failure of the Laminated Wooden Roof of a Covered Swimming Pool

A swimming pool in Corrales de Buelna (Cantabria) was demolished in March 2017 due to the loss of mechanical performance of the laminated timber structure. The relevant deterioration was caused by rotting of the wood and corrosion of the metal connecting elements. The structure featured a barrel vault with five large tri-articulated arches enclosed on the sides by inclined facades formed by toral rafters and purlins. The corresponding diagnostic process involved data collection and structural assessments to verify the structure’s bearing capacity and serviceability. Data collection was carried out in December 2015 and consisted of a thermal camera inspection to determine the points of moisture accumulation and sampling openings, conduct environmental and wood hygrothermal measurements, and measure cross-sectional losses and deformations of the structural elements. Verification of the load-bearing capacity was carried out using matrix calculation structure software for both the original and deteriorated structure. The diagnosis indicated that the damage was caused by leaks in the joints of the aluminum composite roof panels and by the insufficient load-bearing capacity of the structure. The severity of the damage compromised the mechanical strength and stability of the building, leading to a recommendation that the use of the facilities be immediately discontinued. The degree of deterioration left the structure unrecoverable, making it very difficult to apply reinforcement measures. These factors led to the structure’s demolition to prevent its collapse.

ELEMENTOS DE CONEXÃO: A LEGITIMIDADE NA MUDANÇA DA NACIONALIDADE EM PANORAMA INTERNACIONAL

The present study aims to demonstrate whether any change in nationality has legitimacy for international law or if it constitutes an exposed fraud to the guiding law. To achieve the proposed objective, it is intended to highlight, initially, the relationship between international law and the connecting elements, to analyze the legal institute of nationality, the reasons for changing nationality in the enforcement of fundamental rights and, finally, to demonstrate the legitimacy and possible fraud of nationality in an international panorama. To achieve the proposed objective, a bibliographic research was carried out, carried out through the review of theoretical materials related to the theme, as well as the analysis of journals and articles available on the internet, addressing the topic qualitatively, during the month of September 2024. The proposed objective was achieved by understanding the theme in the brief highlight between the relationship between the connecting elements and Private International Law. Then, an analysis of the legal institute of nationality was presented. Soon after, the reasons for changing nationality in the realization of fundamental rights were exposed and, finally, the legitimacy and possible fraud of nationality in the international panorama were demonstrated.

An improved coupled beam method for predicting longitudinal bending behaviour in luxury cruise ships

ABSTRACT This paper describes an improved coupled beam method, designated as MBS-CB, that estimates elastic response in the longitudinal bending of a cruise ship. Initially, the ship structure is discretised into beams, and the coupling relationships between adjacent beams are analysed. Secondly, connector elements with equal stiffness constraints are refined to simulate the coupling behaviour between adjacent beam elements. Meshed beam sections are introduced to simplify the beams involved in total longitudinal bending. A spatial beam system model of the ship structure is established to predict the interaction between adjacent beams and to characterise the longitudinal bending behaviour of the ship. Ultimately, the accuracy of the method is validated through instance analysis. Furthermore, the method is employed to investigate the longitudinal bending characteristics of a large passenger ship, and the participation of different superstructures in the ship's longitudinal bending is obtained through moment distribution coefficients and length proportions.

Charting new territory: the early lessons in integrating social determinant of health (SDOH) measures into practice.

Quality measures for social determinants of health (SDOH) have been introduced or proposed in more than 20 federal programs, initiatives, or guidance documents to capture performance, but understanding the scope of work needed to effectively collect and align with these new measurement requirements is still in its early stages. The National Committee for Quality Assurance (NCQA) recently developed the Social Need Screening and Intervention (SNS-E) measure and is currently building 2 new domains of interest: utility insecurity and social connection. Before these domains can be leveraged to drive population health, the feasibility of collecting and reporting on them must be assessed. This report describes qualitative data collection on the barriers and facilitators of collecting data elements for utility insecurity and social connection from 8 diverse health plans. Although plans reported that collecting SDOH data was feasible, they identified barriers associated with multiple data systems, coding, as well as data formatting, storage, extraction, and mapping. Further research is needed to explore additional codes, mechanisms for collecting SDOH data in a patient-centric manner, and ensuring that health plans, health care systems, and community partners can align with national measurement initiatives. Standardizing these data will be key to improving outcomes for all.

An asymmetric pinching damaged hysteresis model for glubam members: Parameter identification and model comparison

The performance of glue laminated bamboo (glubam) members is governed by the nonlinear response at their joints, where high deformation levels and stress concentrations are developed. Numerous phenomenological models are presently employed to describe the hysteresis behavior of these joints, while these models always have an excessive number of parameters, and the physical interpretation of these parameters is often challenging. Moreover, some hysteresis models cannot capture all hysteresis features such as asymmetry, pinching, and damage. Consequently, this paper introduces a novel phenomenological-based hysteretic model named Asymmetric Pinching Damaged (APD) model, and implemented it in Abaqus by combining connector and spring elements in series or parallel. This model encompasses asymmetry, pinching, and strength degradation for bamboo joint components, with parameters that possess clear physical meanings and are readily comprehensible. This study also presented a parameter identification framework coupling the Parallel Genetic Algorithm (PGA) and Bayesian Neural Network (BNN). By merging the FE modeling and optimizing algorithms with the interactive application of ABAQUS and Python software platforms, the integrated identification framework is capable of performing multi-threaded parallel computation of finite element models considering the BNN-based uncertainty quantification, thus greatly improving the efficiency of parameter identification.

Mindfulness meditation among South African psychologists: a pathway to ‘being’ amid existential suffering in contemporary South Africa

Mindfulness is currently regarded as a life skill as well as part of an approach to life that can generate beneficial intrapersonal and relational outcomes. Given the centrality of intrapersonal and relational outcomes in psychotherapeutic encounters, it seems logical that the practice of mindfulness by psychologists would be relevant to explore, especially in contemporary South African contexts where high levels of trauma, interpersonal distress, and resultant existential and intrapsychic struggles prevail. The study seeks to address an identified gap in existing research concerning the experienced relevance of long-term mindfulness meditative practice for counselling psychology and therapeutic practice generally, particularly in the South African context. Located within an interpretivist paradigm and interpretative phenomenological analysis, this study explored the mindfulness and mindfulness meditation practices of 11 South African counselling psychologists and the ways in which these practices informed their being in both personal and psychotherapeutic settings. Each participant was invited to participate in a semi-structured interview and reflexive journalling task as part of the research process. The findings centralise the being capacities afforded to psychologists through a mindfulness practice and identify how the related elements of non-judgement, nonattachment, and (re)connection enable enhanced relational encounters with clients. The findings contribute to the limited literature related to the value of psychologists’ mindfulness practices in relation to the way in which they manage their own responses to clients, as well as the potential for mindfulness practices to help clients manage presenting trauma responses.

Study on multi-cluster fracture interlaced competition propagation model of hydraulic fracturing in heterogeneous reservoir

The heterogeneity of the reservoir plays a crucial role in influencing the propagation of multi-cluster hydraulic fractures in horizontal wells. To explore this impact, a seepage-stress-damage coupled model was developed in this study for analyzing the competitive propagation of multi-cluster fractures utilizing the finite-discrete element method. Utilizing the model, a random assignment program has been developed to establish the coupling distribution of mechanical parameters between matrix elements and discrete elements for characterizing the reservoir heterogeneity. Simultaneously, a wellbore flow model describing the pressure drop of fracturing fluid flow is developed by introducing pipe flow element and fluid connection element, enabling the realization of dynamic flow distribution. Based on the developed model, an investigation is conducted into the impact of pumping rates, fracturing fluid viscosity, and perforation parameters on the fracture propagation of multi-cluster fracturing. The study findings suggest that as reservoir heterogeneity increases, the distribution of rock strength becomes more uneven, resulting in a more complex morphology of fracture propagation. Higher pumping rates lead to elevated pressure within fractures, thereby facilitating the uniform propagation of multi-cluster fractures, particularly in reservoir characterized by medium to high heterogeneity. Increasing the viscosity of fracturing fluid can diminish the tortuosity of multi-cluster fracture propagation, albeit with a somewhat limited enhancement in uniformity. As reservoir heterogeneity intensifies, the interference between fractures escalates, necessitating a reduced number of perforations to heighten perforation friction and enhance the balanced propagation of multi-cluster fractures. This research offers theoretical guidance and a scientific foundation for the design of schemes and optimization of parameters in staged multi-cluster fracturing technology for horizontal wells in heterogeneous reservoirs.

Opposed Aromatic Surfaces Behave as Independent Binding Sites for Carbohydrate Stacking: Analysis of Sandwich-like CH/π/CH Complexes.

CH/π bonds are versatile elements for the construction of complex molecular architectures, thus playing key roles in many biomolecular recognition processes. Although seldom acknowledged, aromatic units are inherently bivalent and can participate in CH/π bonds through either face simultaneously, leading to the formation of ternary stacking complexes. This sandwich-like arrangement is by far the most common in natural complexes and could potentially lead to negative cooperativity due to unfavorable polarization or electrostatic effects, especially when polarized CH fragments are involved. To evaluate the energetics of such interaction modes, we selected a biologically relevant model, carbohydrate/aromatic stacking, and conducted an experimental analysis comparing binary CH/π interactions to ternary CH/π/CH stacking. Our approach utilized a dynamic combinatorial strategy, which is well-suited to reveal minor stability differences among aromatic complexes. Our results showed that carbohydrate/aromatic stacking is relatively insensitive to molecular recognition events occurring on the opposite side of the aromatic platform, whether exposed to water or involved in additional CH/π contacts, with free energy fluctuations lower than 10%. Based on these data, for all practical purposes, the two opposing aromatic surfaces can be considered independent, noninteracting binding sites, making aromatic platforms optimal connecting elements for supramolecular cross-linking.

Different habitat condition proportions on farms affect the structure and diversity of dung beetle (Coleoptera, Scarabaeidae, Scarabaeinae) communities

The continuous changes and increase of land use into ranching and agriculture have caused shifts in the composition and structure of dung beetle communities due to the modification of vegetation structure. The impact of these changes can be approached using dung beetles as ecological indicators. Agricultural, ranching, and forestry are often integrated into the same farm in different proportions (landscape level), and their degree of integration with habitats changes over time and space. We assessed if different habitat proportions of crop, pasture, and forest land on three farms affect the structure and diversity of dung beetle (Coleoptera: Scarabaeinae) communities. Farms included from three to four habitat conditions each (plantations of timber species, banana-coffee plantation, living fences, pastures, secondary and riparian forest). Pitfall traps with dung and carrion as bait were placed across each habitat condition of each farm during three different sampling periods. Across all samplings, 1,198 dung beetle individuals belonging to 21 species were captured. Species diversity and composition vary according to the type of farm and the main factor that modifies this tendency is the proportion of pasture land composing the farm. Farms with a lower proportion of grazing land (11.96% for forestry farms and 32.19% for agricultural farms) and denser vegetation canopy, which cast more shadows, had greater beetle diversity. Conversely, farms having a greater proportion of grazing land had low diversity and a dominant tendency in the species abundance curve. Umbraphile species dominated the forest farm, indicating a strong affinity for shaded environments such as the one provided there, while species displaying no habitat preference exhibited higher abundance in the ranching farm. Additionally, a notable prevalence of small-sized species was observed in the ranching farm, contrasting with a relatively even distribution of sizes in the remaining landscapes. These tendencies suggest that shade positively influences biodiversity conservation. Riparian vegetation, living fences, and banana-coffee plantations are important connectivity elements in agricultural landscapes for shade-adapted dung beetle species.

A novel meshless method for numerical simulation of fractured-vuggy reservoirs

This paper proposes a novel meshless numerical simulation method for fractured-vuggy reservoirs. Initially, model discretization involves extracting fracture and vug feature nodes along the contours of the reservoir bodies and in alignment with fracture orientations, tailored to the characteristics of the fractured-vuggy oil deposit. Subsequently, a connection element model is established within the influence domain. Based on the seepage equations of the connection system, a computational method for the parameters of the connection elements (connection transmissibility and connection volume) is defined. In addition, a sequential method is employed to solve for the pressure and saturation, achieving rapid prediction of the reservoir's production dynamics. On this basis, an automatic history matching algorithm is utilized for real-time fitting of oil–water dynamic indicators, inverting the characteristic parameters of the connection element model, and quantitatively characterizing the injection–production connection elements. The research findings indicate that the method is capable of rapidly fitting and predicting the dynamics of oil reservoir production. Furthermore, conceptual model examples have substantiated that it achieves comparable computational efficiency and superior computational accuracy when compared to the traditional finite difference (volume) method under the same nodal conditions. Additionally, the node arrangement for fractures and vugs is comparatively flexible, and it can ensure the integrity of the flow paths with a limited number of nodes to enhance predictive accuracy. Therefore, this method can effectively meet the rapid prediction requirements for fractured-vuggy reservoirs and also provides a novel meshless computational approach for the numerical simulation of such reservoirs.

Application of 3D Printing Technology in Furniture Construction.

In recent years, 3D printing technology has become very important in many fields of science, manufacturing, design, medicine, aviation, sports, etc. Furniture design and manufacturing are also not left out of this trend. In this study, the results of bending moments and stiffness of joints of thin structural elements connected by 3D printing with polylactic acid (PLA) connectors are given. The connectors are newly developed, and information on their strength characteristics is lacking in the literature. Ten joints were investigated, made with 9 and 12 mm plywood and 6 mm MDF. The tested joints constructed by 3D-printed connecting elements show a high strength under arm compression bending load, between 44.16 and 24.02 N·m. The stiffness coefficients of joints with 3D-printed connecting elements are between 348 and 145 N·m/rad and are higher than those of conventional detachable mitre joints but lower than those of glued ones. The type of filling of the hollow section of the connecting elements and the wall thickness influenced the joints' strength and stiffness. Reducing the width of the connecting elements from 40 to 30 mm and the inner radius between the arms from 2 to 1 mm does not significantly affect the joints' strength and stiffness coefficients.

Rapid design method for composite emergency steel piers with thin-walled steel tube framework and discussion on "temporary-permanent" transition

To address the conflict between the reserve of repair materials for existing bridge piers and the demands for emergency repairs, as well as the challenge of converting temporary emergency structures into permanent ones without significant disassembly, a novel composite emergency steel pier has been developed. This pier utilizes commonly available thin-walled steel tube sections as the framework, I-beams as the connecting elements, and incorporates a "temporary-permanent" transition function. Taking the emergency steel pier for medium-height bridge piers in high-speed rail systems as an example, this study introduces three evaluation metrics—security coefficient (n), stability coefficient k), and variation coefficient (V)—analyzing the factors influencing the design and application thresholds of the emergency steel piers from perspectives of strength, stability, and load distribution uniformity. Based on this, a rapid design method for composite emergency steel piers with thin-walled steel tube frameworks that does not require numerical simulation has been developed and experimentally validated. Research findings indicate that when used for the emergency repair of medium-height or lower bridge piers in high-speed railways, the column line stiffness of the thin-walled steel tube framework composite emergency steel piers should range between 0.34 × 10 exp7 kN/mm to 4.15 × 10 exp7 kN/mm. The transverse and longitudinal spacing of the columns should be 1 m to 3 m and 1.5 m to 3 m respectively. The line stiffness of the plinth beams I and II should be greater than 0.69 kN/mm and 1.01 kN/mm respectively. Within these parameter ranges, the emergency steel pier will not experience strength failure or instability, and the load distribution among the columns remains uniformly favorable. In applications to other scenarios, the rapid generation of composite emergency steel piers with thin-walled steel tube frameworks can be achieved by following three steps: parameter selection and structural configuration determination, calculation of the pier-beam linear stiffness ratio, and criterion-based result verification. The rapid design and implementation of composite emergency steel piers help alleviate the contradiction between material stockpiling and repair demands. Furthermore, the pre-designed "temporary-permanent" transition functionality facilitates integrated operations for emergency repairs and permanent restorations.

Local inflammatory factors in pregnant women with various methods of cervical insufficiency treatment

the reasons for the formation of cervical insufficiency are considred to be different from violation of the ratio of connective tissue elements due to its genetic characteristics to hormonal imbalance, and the predominance of pro-inflammatory factors of the immune system. A special attention is devoted to clinical situations, when cervical insufficiency was diagnosed in terms 22-24 weeks, the treatment means an alternative between emergency cerclage and obstetric pessary. The gaol of study – to compare dynamic of vaginal microbiota and local cervical immune factors by use of different cervical insufficiency treatment methods. Materials and methods. 81 pregnant with cervical insufficiency, diagnosed in term 22-24 weeks were observed, 47 pregnant treated by cerclage procedure (group A), and 34 were fitted with an obstetric pessary (group B). 30 healthy pregnant women in the period of 22 weeks formed group C. In all patients before treatment and every two weeks after it microscopy of vaginal discharges according to Hay/Ison criteria and evaluation of cervical cytokines were performed. Results. The balance by obstetric pessary use of type I and type III by Hay-Ison criteria being similar before treatment with pregnancy prolongation is changing dramatically to the prevalence of bacterial vaginosis be use of obstetric pessary – from 30,3% and 21,2% in 2 weeks to 25,0% and 41,7% in 6 weeks, by cerclage – from 43,5% and 14,9% in 2 weeks to 30,3% and 17,5% in 6 weeks. Patients with cervical insufficiency have increased concentration of IL-6 and IL-10, but by use of obstetrical pessary additionally growth of IL-8 from 42,3 pg/ml in 2 weeks to 187,6 pg/ml in 6 weeks is registered as well as decreasing of SLPI from 1,5 μg/ml to 0,6 μg/ml. Both changes show progression of inflammation and are associated with worth pregnancy outcomes. In the same time, cerclage is assocated with growth of SLPI from 1,9 μg/ml to 4,3 μμg/ml, what is a marker of adequate immune reaction by pregnancy. There is a difference between the groups of cerclage and obstetric pessary in dynamic of microbiota changes - a tendency to increasing of laboratory criteria of bacterial vaginosis frequency in group of obstetric pessary in 2 weeks becomes significant in 4 and more in 6 weeks comparing with group of cerclage. Proper to cervical insufficiency high concentration of proinflammatory IL-6 and IL-10 by use of obstetrical pessary is complicated by increasing of IL-8 and decreasing of SLPI, what means an activation of cervical inflammation, by cerclage – a increasing of SLPI is observed, what is favourable for pregnancy.

Modeling of residual stiffness phenomenon in modified Iwan model of bolted joints and its application

Bolted joints have been widely used in various mechanical structures. Due to the presence of contact interfaces, the joints exhibit complex nonlinear behavior under dynamic loading. Effective prediction of the dynamic response of bolted structures requires the construction of appropriate dynamic models. This paper proposes a modified Iwan model which gives a more comprehensive description of joints than the previous Iwan models, especially for the phenomenon of residual stiffness in macro slip. The equations of the model's backbone curve, hysteresis curve, and energy dissipation are derived. The parameter identification procedure is also provided. Subsequently, connection elements based on the modified Iwan model are integrated into a single bolted joint and a thin-walled cylinder containing multiple bolted joints, the responses under quasi-static unidirectional loading, quasi-static cyclic loading and constant-frequency excitation are investigated. The physical interpretation of the parameters in the model is discussed, thus explaining the relationship between the bolted joint's physical parameters and some important variables. The results indicate that the model can effectively characterize the nonlinear mechanical behavior of the bolted joint for both micro and macro slip regime, with significant improvement in computational efficiency.