Short-term Compression Research Articles

Роль корекції ендотеліальної дисфункції в комплексній профілактиці гіпертензивних ускладнень вагітності

Purpose - to study the effect of correction of endothelial dysfunction by the introduction of L-arginine in the comprehensive prevention of the development of severe hypertensive disorders in pregnant women. Materials and methods. The division into groups was carried out indiscriminately following the prescribed bath. 27 women reached the 1st group, who, in addition to basic prevention of preeclampsia (small doses of aspirin for 12 days, calcium supplement 1000 mg per dose for 16 years), took Tivortin until conception and p. It's an hour of urgency; up to the 2nd group - 54 women who did not receive basic prevention of preeclampsia. The control group (3) consisted of 16 healthy women with physiological changes in vagusity. Participants of the 1st group, during the hour of stay in the hospital, took L-arginine internally (iv) (4 g) + 2 teaspoons 2 times (4 g) per os per dose 40 minutes before admission, then 3 teaspoons spoons 2 times (6 g per dose). The average intensity of the droplets became 6. The function of the endothelium was evaluated according to the universally recognized non-invasive cuff test method, which is based on the principle of ultrasound assessment of the change in the diameter of the brachial artery in response to the restoration of blood flow in it after short-term compression of the upper limb with a cuff. Physical condition and endurance were assessed using the generally accepted 6-minute walk method. The quality of life in pregnant women who had experienced severe preeclampsia in the past was assessed in stages - according to the health-related quality of life (HRQoL) scale and the scale created by the World Health Organization (WHOQOL-BREF). Results. Arterial hypertension and preeclampsia are based on changes in endothelium-dependent vasodilatation. A positive effect on the function of the endothelium significantly improves indicators of physical well-being and quality of life. When conducting a test with a 6-minute walk in the Group 1, better indicators were found than in the Group 2 (respectively, 409±23 m vs. 381±32 m, p<0.05), this indicator in the control group was 473±32 m (p<0.05 according to the Groups 1 and 2). However, this indicator significantly improved in pregnant women of the Group 1 after intravenous administration of L-arginine: 441±12 m (p<0.05 compared to the indicator before intravenous administration). According to the assessment of the quality of life of pregnant women of the studied groups, it should be noted that the quality of life indicators in all domains are significantly lower in women of the Group 1, which is associated with significantly worse anamnesis data of such women, significant concern about the results of the next pregnancy. When evaluating indicators of endothelium-dependent and endothelium-independent vasodilatation, it was found that in the group of women who received L-arginine preconceptionally, in the 1st trimester, the indicator before intravenous IV administration was 5.09±0.44, and after - 8.21±0.24, which indicates a significant improvement in endothelium-dependent vasodilation indicators (by 49.1%) 28-32 weeks, there are also no births of children with a body weight of less than 1500 g. Conclusions. In the group of high-risk pregnant women, the use of L-arginine in the complex prevention of preeclampsia allows to reduce the risks of early severe preeclampsia, to reduce the medication burden of two- and three-component hypotensive therapy. An increase in physical endurance, quality of life, and improvement in pregnancy outcomes are due to a positive effect on the function of the endothelium through the optimization of endothelium-dependent vasodilatation associated with the provision of the L-arginine substrate for the full synthesis of nitric oxide. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of the participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.

Effect of short-term compression therapy after thermal ablation for varicose veins: study protocol for a prospective, multicenter, non-inferiority, randomized controlled trial

BackgroundFor patients with varicose veins, the goal is to relieve pain and swelling, reduce the severity of edema, improve skin changes, and heal ulcers associated with venous disease. Compression therapy is the cornerstone of their management. Several studies have shown that wearing an elastic bandage for the first 24 h and then a compression stocking for a week can effectively reduce the pain after thermal ablation. However, in clinical practice, patient compliance with this treatment could be better, considering difficulties in pulling up and removing the compression stocking, tightness, and skin irritation because these must be worn for a prolonged period. A potential solution to battling these barriers is short-term compression therapy. Besides, the effect and necessity of wearing compression stockings after thermal ablation have been questioned. Based on current clinical experience and limited evidence, although some scholars have suggested that compression therapy may be an unnecessary adjunctive therapy after thermal ablation, there is still a great deal of uncertainty in the absence of compression therapy after thermal ablation compared to compression therapy. Therefore, we advocate further research to evaluate the clinical effect of short-term postoperative compression therapy. Furthermore, well-designed randomized controlled trials are needed.MethodsA prospective, multicenter, non-inferiority randomized controlled trial is designed to evaluate the non-inferiority of target vein occlusion rate at 3 months. Three hundred and sixty patients will be randomly assigned in a 1:1 ratio to one of the following treatments: (A) 3 M™ Coban™ elastic bandage for 48 h or (B) 3 M™ Coban™ elastic bandage for the first 24 h and then a class II compression full-length stocking (23–32 mm Hg) for 1 week. The two groups will be compared on several variables, including target vein occlusion rate at 3 months (primary outcome indicator), pain, quality of life, clinical severity of varicose veins, postoperative complications, time to return to regular work, and compliance.DiscussionSuppose the effect of the 3 M™ Coban™ elastic bandage for 48 h proves to be non-inferior to long-term compression therapy. In that case, this short-term treatment may contribute to a future update of clinical guidelines for compression therapy after thermal ablation of varicose veins, resulting in higher patient compliance and better postoperative quality of life.Trial registrationClinical Trials NCT05840991. Registered on May 2023.

Paleostress regime evolution in South China induced by dynamic changes in Izanagi-Pacific subduction since the Cretaceous

A complex intraplate deformation sequence since the Cretaceous is recorded in the basin–mountain belt along the South China continental margin and provides a critical window to reconstruct the paleostress regime since the Cretaceous and further explore the relationship between the intraplate deformation episodes in South China and the dynamic changes in Izanagi-Pacific subduction. Here, integrating the clues from the field investigation, fault-slip inversion, and zircon U–Pb chronology in four regions along the basin–mountain belt reveals six paleostress regimes on the South China margin, listed in order of decreasing age: E‒W extension (ca. 145-120 Ma), NW‒SE extension (ca. 120-105 Ma), NW‒SE compression (ca. 105-100 Ma), N–S extension (ca. 100-65 Ma), NE‒SW compression (ca. 65-55 Ma), and NE‒SW extension (ca. < 55 Ma). The four extensional regimes controlled regional subsidence and sedimentation, resulting in NW-striking and E–W-striking alignments of Early and Late Cretaceous basins, respectively. In comparison, the two compressional regimes produced two regional unconformities between the Early and Late Cretaceous strata and between the Late Cretaceous and Paleogene strata. Our results suggest that the prevailing Cretaceous extension in South China likely started at ca. 145 Ma, reversed due to short-term compression, and restarted at ca. 100 Ma. By comparing the history of the Izanagi-Pacific plate subduction, we conclude that the dynamic changes in the subduction process have been the primary force driving intraplate deformation in South China since the Cretaceous.

Analysis of Active and Passive Deformation of Expanded Polystyrene Foam under Short-Term Compression

In this paper, we undertake a detailed analysis of the active and passive deformation of expanded polystyrene (EPS), which is used as a thermal insulating layer in building partitions, under short-term compressive loading. The values of residual strain in 10-40 kg/m3 density EPS after monotonically increasing loading under active deformations of 20%, 30%, 40%, 50%, and 60% with the following complete removal are determined. These values are a physical sign of the elastic-plastic state of EPS. It has been shown that the final destruction of cells takes place in EPS when the active strain reaches 50%. Empirical equations are proposed to estimate the residual strain of EPS based on density with determination coefficients varying from 0.744 to 0.986 at a confidence level of 90%. Moreover, graphical interpretations with regression equations for residual strain dependence on density and compressive strength, as well as density and active strain, were proposed with determination coefficients equal to 0.779 and 0.717, respectively.

Hierarchical 3D Printed Porous Silicones with Porosity Derived from Printed Architecture and Silicone-Shell Microballoons

A method is reported to prepare siloxane microballoons that can be loaded into a direct ink write siloxane ink for 3D printing. The resulting structure is subjected to a solvent removal and supercritical drying process to provide a final printed siloxane having both macroscopic and microscopic porosity. Core-shell particles are generated by an emulsion template and phase separation process. Intra-strand closed-cell porosities can be achieved between 10 and 40 vol% thus facilitating additional compressive strain before lockup. Short term compression set testing highlights the excellent shape retention properties of these elastomers, which have less than 8% relative compression set under load.

Short-Term Oxidation Behavior, Microstructure Evolution and Compression Behavior of Nickel-Based Superalloy GH4037 in Solid and Semi-Solid States

Semi-solid processing combines the advantages of traditional forging and casting methods, so it has received much attention recently. However, the research on semi-solid behaviors of Nickel-based superalloys has been rarely reported. In order to investigate the behaviors of Nickel-based superalloy at solid and semi-solid states, oxidation experiments, isothermal treatment experiments and deformation experiments of GH4037 alloy were studied. Short-term oxidation experiments of GH4037 alloy were carried out at a solid temperature (1200 °C) and a semi-solid temperature (1360 °C). The results indicated that the oxides formed at 1200 °C were mainly composed of TiO2, Cr2O3 and a small amount of spinels NiCr2O4, while the oxides formed at 1360 °C consisted of the spinels of NiCr2O4, NiWO4 and NiMoO4 besides TiO2 and Cr2O3. Microstructure evolution of GH4037 alloy after semi-solid isothermal treatment at 1370 °C and 1380 °C was studied. The results indicated that semi-solid microstructures consisted of equiaxed solid grains and liquid phases. The average grains size and shape factor of solid grains were affected by melting mechanism and grain growth mechanism. Compression behaviors of GH4037 alloy after compressed at 1200 °C and 1360 °C were investigated. The results indicated that the flow stress of 1360 °C decreased significantly compared to that of 1200 °C. The deformation zones in the specimens were divided into three parts: the difficult deformation zone, the large deformation zone, and the free deformation zone. At 1200 °C, the deformation mechanism was plastic deformation mechanism. At 1360 °C, sliding between solid particles (SS), liquid flow (LF), flow of liquid incorporating solid particles (FLS), plastic deformation of solid particles (PDS) coexisted in the compression specimen.

Transformation of concrete deforming diagrams in conditions of uniform and non-uniform stress states

The aim of the research is formulated, which is the theoretical substantiation, development and testing of the concrete state diagram, suitable for use to calculations of the strength of bended reinforced concrete elements based on the deformational model, as well as for more complete assessment of non-uniform stress-strain state of the cross-sections of elements at all stages of their loading up to the destruction directly on the values of the relative strains of concrete and the corresponding stresses.&#x0D; In this paper, an analytical method of converting the parameters of reference concrete deforming diagrams, which are determined experimentally during standard tests of concrete prismatic specimens by short-term axial compression and tension up to the destruction in «soft» mode of loading, into parameters of simulated transformed diagrams, which correspond to the «rigid» mode of loading of concrete, is developed. The way of simultaneous application of analytical expressions for the specified defoming diagrams, which describe the operation of concrete in conditions of uniform compression, for transition to the state diagram, which displays the functional relationship between the stresses and strains of the concrete compressed zone in bended concrete and reinforced concrete elements, cross-sections of which operate in conditions of non-uniform stress state, is proposed.&#x0D; The results of testing the obtained mathematical model of the concrete state diagram during the calculation by different methodics of strength of the normal cross-sections of bendable reinforced concrete elements are presented.&#x0D; It has been determined that a promising direction for further experimental and theoretical research is the study of the application of the developed methodics of graphical building and mathematical descripting of concrete deforming diagrams under conditions of uniform and non-uniform compression to the calculation of concrete and reinforced concrete elements that are operated under the action of long-term and short-term low-cycle loadings.

Short-term compression therapy in chronic vein disease without trophic disorders: possibilities of medical compression knitwear

Introduction.Medical compression stockings are one of the main methods in a conservative strategy for the treatment of chronic vein diseases as well as for adjuvant treatment after superficial venous interventions. however, compliance to this treatment is low.Objective.To evaluate patient satisfaction with medical compression knitwear therapy in a short-term follow-up.Materials andмethods.The study included 150 patients of both sexes aged 42 ± 8.3 years. Endovenous laser obliteration combined with mini-phlebectomy and/or sclerotherapy for varicose veins was performed. All patients after the surgery wore compression stockings of compression class 2 with a recommended wearing period of 14 days. At the control visit at the end of the follow-up period all patients were asked to complete a satisfaction survey with a specially prepared questionnaire including 7 questions.Results and discussion.No significant adverse events and complications related to either the invasive intervention or the compression therapy were observed during the follow-up period. There were no abnormalities such as compression sensations or changes in blood flow under the knitwear. The compression was totally adequate, with no areas of over- and/or under-compression. All respondents felt that the knitwear was well anchored to the leg and no slipping or twisting due to the wide elastic band with droplet silicone. In addition to all of the above, the patients noted that the knitwear offered to them in the study had good tactile properties: it was soft and pleasant to the skin. According to the survey, the average score for all questions was 9.5 (QR 8-10).Conclusion.Elastic compression is an effective and safe means of preventing adverse events, complications and pain in patients after superficial varicose veins surgery. Additional consumer properties of medical compression knitwear can significantly influence patients’ compliance and therefore the effectiveness of treatment.

Compensatory Changes of the Diastole under Conditions of Inflow Restriction to the Heart.

This work was designed to study changes in the mechanical properties of rat myocardium during short-term (2-3 sec) compression of the lower vena cava. A catheter was inserted into the left ventricle, allowing simultaneous measurement of left-ventricular volume and pressure. The decrease in the left-ventricular end-diastolic volume caused by inflow restriction was accompanied by less pronounced decrease in the left-ventricular stroke volume and maximum rate of left-ventricular pressure development. This was coincided with accelerated relaxation and deeper fall of the minimum left-ventricular diastolic pressure. The lower was left-ventricular end-systolic volume, the greater was the degree of these changes. It is assumed that the "restoring force" that naturally appears under conditions of low filling of the left ventricle is determined by elastic N2B part of the titin molecule that is compressed during strong shortening of myofibrils and accelerates their return to the previous length during relaxation. As a result of better filling of the left ventricle, the heart can maintain left-ventricular stroke volume at the appropriate level.

Short-term compression therapy following invasive treatments of superficial venous disorders

Short-term compression therapy following invasive treatments of superficial venous disorders

Study of the Influence of Pine Wood Shelf Life on Endurance under Compression along the Grains

Purpose of research. Study of the influence of pine wood shelf life on endurance under compression along the grains, as well as grounds for results obtained. Wood is anisotropic, depending on the grains, the mechanical and physical properties of the material differ greatly. Methods Wood is anisatropic, the change in its endurance depends not only on conditions, shelf life, moisture, but also on the direction of the grains in the timber. However, the relevance of using this material still remains unchanged. The tests were carried out on a press of the UM-5 type. After carrying out the compression test, moisture tests were performed and the test results of the specimens were reported at 12% moisture. Untested samples were stored from 1981 to 2019 in the laboratory of the Department of Industrial and Civil Engineering at South-West University. In 2019, the stored samples were prepared for testing and tested. Results. To obtain substantiated data on the influence of wood shelf life on endurance, an experiment was carried out with the bars that had undergone a 39-year wait in the laboratory of the Department of Industrial and Civil Engineering. From among the samples, 16 samples were selected, which were tested for short-term compression load along the grains. For these samples diagrams “Load-displacement” were recorded on the press UM-5. The experiment showed two types of sample destruction which led to the corresponding conclusion. Conclusion. The strength characteristics revealed as a result of experiments from core and sapwood of pine on samples 20x20x30 in 1981 and in 2020 significantly differed from normal ones, this was influenced by a relatively small number of samples.

Clinical outcome of short-term compression after sclerotherapy for telangiectatic varicose veins

BackgroundSclerotherapy is considered to be the method of choice for the treatment of telangiectatic varicose veins (C1 veins). Whereas the use of compression stockings after sclerotherapy is recommended, little is known about the impact of compression on the outcome of sclerotherapy. The aim of this study was to assess the influence of compression on the outcome of injection sclerotherapy of C1 varicose veins. MethodsThere were 100 legs of 50 consecutive patients with chronic venous insufficiency (C1) included. After randomization per patient, both legs were treated with sclerotherapy in a predefined area of the thigh (measuring 100 cm2), followed by eccentric compression for 24 hours. Group A received no further compression, whereas group B was additionally equipped with compression stockings of 18 to 20 mm Hg above the ankle and continued wearing these for 1 week. Photodocumentation was performed before, 1 week after, and 4 weeks after sclerotherapy, and the clinical outcome was assessed at these postprocedure follow-up dates. The photographs were reviewed by an internal unblinded rater and an independent blinded external rater. ResultsThere was no discernible difference between the groups in terms of clinical outcome or side effects after 4 weeks. Whereas inter-rater reliability was high, there was no correlation between the raters and patients in terms of outcome. In 55% of the treated legs, the patients deemed the result of the treatment to be good; in 27% of the treated legs, fair; and in 18%, poor. Postprocedure hyperpigmentation occurred in 13% of patients and was comparable in both groups. Compression therapy was found to be comfortable by the majority (58%) of patients. ConclusionsOne week of postinterventional compression therapy had no clinical benefit compared with no compression.

ДЕФОРМАЦИИ РАСТВОРА ГОРИЗОНТАЛЬНЫХ ШВОВ КАМЕННОЙ КЛАДКИ ПРИ СЖАТИИ

The necessity of establishing and determining the consistency of mortars deformation in the horizontal joints of masonry is established: in the absence and development of cracks and with the exhaustion of resistance ranging from 80 – 85 % of the total deformation of masonry under short-term compression. Attention is paid to the absence of reports in the scientific literature on the conduct and results of research on the spatial stress-deformative state of the mortar in the joints of masonry under compression. The advantages of studying the secant modulus of deformation Ep are emphasized in solving various issues in the theory of operation and method for calculating the masonry. On the basis of long-term research results, the essential difference between the change in the secant modulus of cement mortars deformation E'p of varying strength of horizontal joints from the nature of its change when tested in standard samples is shown analytically and graphically. The advantages of the developed methodology for processing the results of investigations of mortars in standard samples are noted. It allows to more accurately set the actual values of normal strain modulus E0 and the ultimate relative deformation under compression. The analytical dependences of the plasticity coefficient and the secant modulus of deformations E'p are found based on processing the results of numerous studies of masonry mortars

Anisotropy of strength properties of aluminate cement after exposure to single-axis loading at early stage of hardening

The article considers the impact of short-term compression at an early age on the flexural strength of aluminate cement. Taking into account the results of the previous research, the authors took the samples with the identical planes instead of prisms. The change in splitting tensile strength of pre-stressed samples at different planes has been analyzed. The studies have shown cement hardening in a plane perpendicular to the direction of short-time compression. It can be explained by the compaction of cement stone, decrease in porosity and formation of additional bonds through the chemical-plastic hardening, as noted by F. J. Ulm and O. Coussy. The research revealed that, after the removal of load, the difference between the strength of pre-stressed and control samples tends to reduce. The X-ray phase analysis demonstrates the difference in the hydration process in the first 24 hours after loading and change in the recrystallization of hexagonal hydroalumates into cubic crystals.

Tissue flossing: a new short-term compression therapy for reducing exercise-induced delayed-onset muscle soreness. A randomized, controlled and double-blind pilot crossover trial.

The symptomatic reduction of exercise-induced delayed-onset muscle soreness (DOMS) is of great interest in the fields of Sports Medicine and Physical Therapy. At this time, few therapeutic interventions have proven their effectiveness. One of the most promising interventions is compression therapy. The object of this study is tissue flossing, a therapeutic short-term compression method and whether its post-exercise application can reduce the extent of perceived DOMS. Participants (N.=17) without any musculoskeletal injuries were recruited from university students. Participants performed an exercise protocol and obtained the intervention subsequently on one of both arms. Participants had to return for a second day to perform the whole procedure again, this time receiving the flossing intervention on the other arm. At both timepoints, their opposite arms served as the control. The primary outcome measure was a patient-reported score on a 100-mm Visual Analogue Scale. The mean value of DOMS of the flossed arm was 42 mm compared to the non-flossed arm was 48 mm. Differences were found to be statistically significant at 24 hours (P=0.036; α=0.05), as well as at 48 hours post-intervention (P=0.035; α=0.05). Effect sizes were dz=0.408 at 24 hours-and dz=0.411 at 48 hours post-intervention. The clean language effect size was 0.66. Tissue flossing appears to be an effective method for treating DOMS which is slightly less effective but much more practicable than gold standard treatment.

Abstract A38: Modeling ascites-induced changes in peritoneal mechanobiology and ovarian cancer metastatic success

Abstract Ovarian cancer (OvCa) is frequently accompanied by accumulation of intraperitoneal ascites fluid early in disease progression. This fluid is rich in soluble and cellular components including tumor cells and multicellular aggregates (MCAs) of 150-300 um diameter shed from the primary tumor. In addition to chemical cues, ascites fluid buildup can also alter the force environment in the peritoneal cavity, thereby impacting the primary tumor, disseminating cells and MCAs, and host peritoneal tissues. Whereas the intraperitoneal pressure (IPP) of the normal peritoneal cavity is subatmospheric (-5 mmHg), the IPP measured in ovarian cancer patients with tense ascites is reported to be 24 mmHg. The potential effect of ascites-induced changes in peritoneal mechanobiology on tumor cells and host structures has not been investigated due to a lack of appropriate model systems. As a first approximation, we have begun preliminary investigations into the response of tumor and host structures to compressive and strain (stretching) forces. Our initial experiments used MCAs sealed in nonadherent cell culture bags placed into a temperature-controlled stainless-steel pressure vessel and subjected to a compressive force of 22-24 mmHg using an Instron system. While this approach is feasible for short-term experiments, longer-term compression experiments require a system with gas exchange to maintain cell viability. Thus, we fabricated a mold designed to fit within a Flexcell-400C Compression system Biopress+ Bioflex 6-well plate. This mold was used to produce porous hydrogels containing defined void areas so as to encapsulate MCAs within the hydrogel carrier and thereby ensure a more uniform encounter with the Flexcell compression plate. Our initial experiments investigated the effects of MCA compression on gene expression associated with epithelial-to-mesenchymal transition (EMT). Data indicate that short-term static compression (6h) downregulates CDH2 (N-cadherin, Ncad) with cell line-dependent inhibition of EMT regulators including SNAI1, SNAI2, and TWIST. In contrast, long-term compression (24h) upregulated expression of mesenchymal genes including CDH2, MMP14, Wnt5a, ROR1, and ROR2. To examine the impact of strain on receptivity of host peritoneal tissues to metastatic implantation, we used control or strained ex vivo explants of murine peritoneal tissue immobilized on silastic resin. Strained peritoneal tissue exhibited a 3-fold increase in stiffness as determined by atomic force microscopy. Concomitantly, adhesion of ovarian cancer cells to strained peritoneum increased by 4.5-fold. Together these data provide support for a more detailed investigation of the complex role of peritoneal mechanobiology as an important microenvironmental regulator of ovarian cancer metastatic success. Citation Format: Yuliya Klymenko, Rebecca Wates, Yueying LIu, Rachel Lombard, Holly Weiss-Bilka, Leigh Campbell, Diane Wagner, Matthew J. Ravosa, M. Sharon Stack. Modeling ascites-induced changes in peritoneal mechanobiology and ovarian cancer metastatic success. [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr A38.

Experimental and Numerical Investigation on Compression Creep Behavior of Wood

Abstract This article provides an efficient and intuitive way to predict the long-term (12-h) compression creep behavior of wood by a finite element method (FEM). In this study, oriental beech (Fagus orientalis L.) was used as an example. First, a short-term (3-h) compression creep experiment was conducted to obtain the original creep data of beech, and then a Kelvin model (KM) with two elements in series was applied to fit the curve of creep strain and time to calculate parameters used in FEM. Second, long-term compression creep behavior was numerically analyzed by the FEM based on the short-term creep data. Finally, the results of the FEM and the KM were compared with that of the long-term creep experiment. The results showed that the creep deformations increased in the order of longitudinal (L), radial (R), and tangential (T) directions under the same loading level, and the creep behavior of beech in the L direction stopped after a short time and stayed constant. Additionally, in the same orientation, the creep deformation increased with the growth of loading levels below the ultimate creep strength. In addition, the KM did not work well for predicting the long-term creep behavior of beech. By contrast, the results of FEM were highly consistent with those of the experiment, and errors in L, R, and T directions were all less than the standard deviation. As a result, the numerical method provided acceptable accuracy to predict the long-term creep behavior of wood construction and wood products.

Failure of structural elements made of polymer supported composite materials during the multiyear natural aging

Modern high-rise construction introduces a number of limitations and tasks. In addition to durability, comfort and profitability, projects should take into account energy efficiency and environmental problems. Polymer building materials are used as substitutes for materials such as brick, concrete, metal, wood and glass, and in addition to traditional materials. Plastic materials are light, can be formed into complex shapes, durable and low, and also possess a wide range of properties. Plastic materials are available in various forms, colors and textures and require minimal or no color. They are resistant to heat transfer and diffusion of moisture and do not suffer from metal corrosion or microbial attack. Polymeric materials, including thermoplastics, thermoset materials and wood-polymer composites, have many structural and non-structural applications in the construction industry. They provide unique and innovative solutions at a low cost, and their use is likely to grow in the future. A number of polymer composite materials form complex material compositions, which are applied in the construction in order to analyze the processes of damage accumulation under the conditions of complex nonstationary loading modes, and to determine the life of structural elements considering the material aging. This paper present the results of tests on short-term compression loading with a deformation rate of v = 2 mm/min using composite samples of various shapes and sizes.

Reorganized neural activation in motor cortex following subdural fluid collection: an fMRI and DTI study

ABSTRACTWe report a patient with a cavernous malformation involving the right lentiform nucleus. Pre-surgical planning included fMRI localization of language, motor, and sensory processing, and DTI of white matter tracts. fMRI results revealed no activation near the planned resection zone. However, post-surgery the patient developed a subdural fluid collection, which applied pressure to the primary motor cortex (M1). Follow-up scans revealed that motor activation had shifted due to pressure, and then shifted to a new location after the fluid collection subsided. This case report suggests that long-term neural reorganization can occur in response to short term compression in the cortex.

Long-term load duration induces N-cadherin down-regulation and loss of cell phenotype of nucleus pulposus cells in a disc bioreactor culture.

Long-term exposure to a mechanical load causes degenerative changes in the disc nucleus pulposus (NP) tissue. A previous study demonstrated that N-cadherin (N-CDH)-mediated signalling can preserve the NP cell phenotype. However, N-CDH expression and the resulting phenotype alteration in NP cells under mechanical compression remain unclear. The present study investigated the effects of the compressive duration on N-CDH expression and on the phenotype of NP cells in an ex vivo disc organ culture. Porcine discs were organ cultured in a self-developed mechanically active bioreactor for 7 days. The discs were subjected to different dynamic compression durations (1 and 8 h at a magnitude of 0.4 MPa and frequency of 1.0 Hz) once per day. Discs that were not compressed were used as controls. The results showed that long-term compression duration (8 h) significantly down-regulated the expression of N-CDH and NP-specific molecule markers (Brachyury, Laminin, Glypican-3 and Keratin 19), attenuated Alcian Blue staining intensity, decreased glycosaminoglycan (GAG) and hydroxyproline (HYP) contents and decreased matrix macromolecule (aggrecan and collagen II) expression compared with the short-term compression duration (1 h). Taken together, these findings demonstrate that long-term load duration can induce N-CDH down-regulation, loss of normal cell phenotype and result in attenuation of NP-related matrix synthesis in NP cells.