Intact State Research Articles

Augmentation of Nitric Oxide Deficient Hypertension by High Salt Diet Is Associated With Reduced TNF-α Receptor Type 1 Expression in the Kidneys.

High salt (HS) intake induces an augmented hypertensive response to nitric oxide (NO) inhibition, though it causes minimal changes in blood pressure (BP) in NO intact condition. The cause of such augmentation is not known. HS induces tumor necrosis factor-alpha (TNFα) production that causes natriuresis via activation of its receptor type 1 (TNFR1). We hypothesized that NO deficiency reduces renal TNFR1 activity, leading to enhanced sodium retention and hypertension. We examined the changes in renal TNFR1 protein expression (Immunohistochemistry analyses) after HS (4% NaCl) intake in wild-type mice (WT, C57BL6) treated with a NO synthase (NOS) inhibitor, nitro-l-arginine methyl ester (L-NAME; 0.05 mg/min/g; osmotic mini-pump), as well as in endothelial NOS knockout mice (eNOSKO) and compared the responses in WT mice with normal salt (NS; 0.3% NaCl) intake. BP was measured with tail-cuff plethysmography and 24-hour urine collections were made using metabolic cages. HS alone did not alter mean BP in untreated mice (76 ± 3 to 77 ± 1 mm Hg) but induced an augmented response in L-NAME treated (106 ± 1 vs. 97 ± 2 mm Hg) and in eNOSKO (107 ± 2 vs. 89 ± 3 mm Hg) mice. The percentage area of TNFR1 expression in renal tissue was higher in WT + HS (4.1 + 0.5%) than in WT + NS mice (2.7 ± 0.6%). However, TNFR1 expression was significantly lower in L-NAME treated WT + NS (0.9 ± 0.1%) and in eNOSKO + NS (1.4 ± 0.2%) than in both WT + NS and WT + HS mice. These data indicate that TNFR1 activity is downregulated in NO deficient conditions, which facilitates salt retention leading to augmented hypertension during HS intake.

Effect of a Partial Superficial and Deep Medial Collateral Ligament Injury on Knee Joint Laxity.

Injuries to the medial collateral ligament (MCL), specifically the deep MCL (dMCL) and superficial MCL (sMCL), are both reported to be factors in anteromedial rotatory instability (AMRI); however, a partial sMCL (psMCL) injury is often present, the effect of which on AMRI is unknown. To investigate the effect of a dMCL injury with or without a psMCL injury on knee joint laxity. Controlled laboratory study. Sixteen fresh-frozen human cadaveric knees were tested using a 6 degrees of freedom robotic simulator. The anterior cruciate ligament (ACL) was cut first and last in protocols 1 and 2, respectively. The dMCL was cut completely, followed by an intermediary psMCL injury state before the sMCL was completely sectioned. Tibiofemoral kinematics were measured at 0°, 30°, 60°, and 90° of knee flexion for the following measurements: 8 N·m of valgus rotation (VR), 4 N·m of external tibial rotation, 4 N·m of internal tibial rotation, and combined 89 N of anterior tibial translation and 4 N·m of external tibial rotation for both anteromedial rotation (AMR) and anteromedial translation. The differences between subsequent states, as well as differences with respect to the intact state, were analyzed. In an ACL-intact or -deficient joint, a combined dMCL and psMCL injury increased external tibial rotation and VR compared with the intact state at all angles. A significant increase in AMR was seen in the ACL-intact knee after this combined injury. Cutting the dMCL alone showed lower mean increases in AMR compared with the psMCL injury, which were significant only when the ACL was intact in knee flexion. Moreover, cutting the dMCL had no effect on VR. The ACL was the most important structure in controlling anteromedial translation, followed by the psMCL or dMCL depending on the knee flexion angle. A dMCL injury alone may produce a small increase in AMRI but not in VR. A combined dMCL and psMCL injury caused an increase in AMRI and VR. In clinical practice, if an increase in AMRI at 30° and 90° of knee flexion is seen together with some increase in VR, a combined dMCL and psMCL injury should be suspected.

Comparative Biomechanical Stability of the Fixation of Different Miniplates in Restorative Laminoplasty after Laminectomy: A Finite Element Study

A novel H-shaped miniplate (HSM) was specifically designed for restorative laminoplasties to restore patients’ posterior elements after laminectomies. A validated finite element (FE) model of L2/4 was utilized to create a laminectomy model, as well as three restorative laminoplasty models based on the fixation of different miniplates after a laminectomy (the RL-HSM model, the RL-LSM model, and the RL-THM model). The biomechanical effects of motion and displacement on a laminectomy and restorative laminoplasty with three different shapes for the fixation of miniplates were compared under the same mechanical conditions. This study aimed to validate the biomechanical stability, efficacy, and feasibility of a restorative laminoplasty with the fixation of miniplates post laminectomy. The laminectomy model demonstrated the greatest increase in motion and displacement, especially in axial rotation, followed by extension, flexion, and lateral bending. The restorative laminoplasty was exceptional in preserving the motion and displacement of surgical segments when compared to the intact state. This preservation was particularly evident in lateral bending and flexion/extension, with a slight maintenance efficacy observed in axial rotation. Compared to the laminectomy model, the restorative laminoplasties with the investigated miniplates demonstrated a motion-limiting effect for all directions and resulted in excellent stability levels under axial rotation and flexion/extension. The greatest reduction in motion and displacement was observed in the RL-HSM model, followed by the RL-LSM model and then the RL-THM model. When comparing the fixation of different miniplates in restorative laminoplasties, the HSMs were found to be superior to the LSMs and THMs in maintaining postoperative stability, particularly in axial rotation. The evidence suggests that a restorative laminoplasty with the fixation of miniplates is more effective than a conventional laminectomy due to the biomechanical effects of restoring posterior elements, which helps patients regain motion and limit load displacement responses in the spine after surgery, especially in axial rotation and flexion/extension. Additionally, our evaluation in this research study could benefit from further research and provide a methodological and modeling basis for the design and optimization of restorative laminoplasties.

Biomechanical impact of meniscal ramp lesions on knee joint contact characteristics in ACL deficient knees: a cadaveric analysis.

To evaluate the changes in contact characteristics of the tibiofemoral joint resulting from a meniscal ramp lesion in the medial meniscus. Twelve cadaveric knees (six matched pairs) were subjected to a 600N axial load using a custom testing jig, which allowed for knee positioning at 0°, 45°, and 90° of flexion without other constraints. The knees were randomly assigned to either a ramp lesion group (n = 6) or a posterior root lesion group (n = 6). Four testing conditions were examined: (1) intact, (2) isolated ramp lesion, (3) isolated posterior root tear of the medial meniscus, and (4) combined ramp lesion and posterior root tear of the medial meniscus. Contact characteristics were evaluated using a flexible pressure sensor, the I-Scan System. Peak contact pressure in isolated ramp lesions (4.15 ± 0.98MPa, P = 0.206) showed non-significant increases compared to the intact condition (3.86 ± 1.32MPa). Peak contact pressure in isolated posterior root tears (4.58 ± 1.70MPa, P = 0.040) and, combined ramp and posterior root lesions (4.67 ± 1.47MPa, P = 0.003) were significantly higher than that in the intact condition. The knee flexion position significantly affected the medial tibiofemoral joint's contact area, contact pressure, and peak contact pressure (P < 0.001 for all). Isolated ramp lesions did not significantly impact force transmission, contact area, or contact pressure. In contrast, isolated root lesions and combined ramp and posterior root tears of the medial meniscus significantly intensified the changes in contact characteristics in the medial tibiofemoral joint compared to the intact condition. Level III.

Influence of Isolated Talonavicular and Subtalar Joint Arthrodesis on Hindfoot Kinematics and Range of Motion During Cadaveric Gait Simulation.

Isolated subtalar and talonavicular joint arthrodeses have been associated with adjacent joint arthritis and altered hindfoot kinematics during simplified loading scenarios. However, the effect on kinematics during dynamic activity is unknown. This study assessed changes in subtalar and talonavicular kinematics after isolated talonavicular (TNiso) and subtalar (STiso) arthrodesis, respectively, during stance simulations. Fourteen midtibia specimens received either a TNiso or STiso arthrodesis, with 7 randomized to each group. A 6-degree-of-freedom robot sequentially simulated the stance phase for the intact and arthrodesis conditions. Bootstrapped bias-corrected 95% CIs of the talonavicular and subtalar joint kinematics were calculated and compared between conditions. The TNiso decreased subtalar inversion, adduction, and plantarflexion in late stance (P < .05). The subtalar range of motion in the sagittal and coronal planes decreased by 40% (P = .009) and 46% (P = .002), respectively. No significant changes in talonavicular joint kinematics were observed after isolated subtalar arthrodesis; however, the range of motion was reduced by 61% (P = .007) and 50% (P = .003) in the coronal and axial planes, respectively. In this model for arthrodesis, changes in subtalar kinematics and motion restriction were observed after isolated talonavicular arthrodesis, and motion restriction was observed after isolated subtalar arthrodesis. Surprisingly, talonavicular kinematics did not appear to change after isolated subtalar arthrodesis. Both joint fusions substantially decrease the motion of the reciprocal adjacent joint. Surgeons should be aware that the collateral costs with talonavicular fusion appear higher, and it has a significant effect on subtalar kinematics during the toe-off phase of gait.

Concept Design of a 15 MW TLP-Type Floating Wind Platform for Korean Offshore Installation

Offshore wind farms on the east offshore of Korea to produce multi-GW power from floating wind platforms are being planned. The objectives of the present study are to develop a new TLP-type floating wind platform with a 15 MW turbine for the planned site and to confirm the feasibility of the TLP design under extreme typhoon environments. The concept design of the 15 MW TLP floating platform was completed for installation at a water depth of 137 m. The platform was vertically moored with highly pretensioned wire rope tendons. The platform and tendons were designed to withstand extreme conditions for up to 50 years. Additionally, a platform with an integrated turbine was designed to be wet-towable from the quayside without dedicated vessels to minimize the pre-service cost and risk. An extreme response analysis was conducted to evaluate the platform motion, acceleration, airgap and tendon tension for wave variation, intact and damaged condition of the tendon, environment heading change, and water level variation. The platform design results were validated using the design criteria from the industry standards and recommendations, and the design was verified to comply with the design requirements for the planned sites.

Leakage characteristics of plug flow in the case of pipe leakage

AbstractIn order to study the changes in two‐phase flow parameters after pipeline damage and the impact of gas injection on water leakage from damaged pipelines, experimental and simulation studies were conducted on the damaged pipelines. The main objective is to compare the void fraction in intact and damaged states and to investigate the factors influencing and variations in gas–liquid leakage flow rates. The results show that increasing the liquid superficial velocity can reduce the difference in void fraction distribution caused by different damage directions. The leakage flow rate is affected by the direction of damage and the superficial velocity of the respective phase. It has been discovered that gas injection in the pipeline can make it easier to find small‐area pipeline damage. The change rate of the volume void fraction shows different changes with the increase in gas proportion in different directions; the shape of the bubble has no bearing on this change.

The Kouvalchouk procedure vs. distal tibial allograft for treatment of posterior shoulder instability: the deltoid “hammock” effect exists

BackgroundIn 1993, Kouvalchouk described an acromial bone block with a pedicled deltoid flap for the treatment of posterior shoulder instability. This procedure provides a “double blocking” effect in that the acromial autograft restores posterior glenoid bone loss and the deltoid flap functions as a muscular “hammock” resembling the sling effect of the conjoint in the Latarjet procedure. The primary aim of this study was to compare the Kouvalchouk procedure to distal tibial allograft (DTA) reconstruction for the management of posterior shoulder instability with associated bone loss, while the secondary aim was to evaluate the deltoid hammock effect. s MethodsTen upper extremity cadavers were evaluated using a validated shoulder testing apparatus in 0° and 60° of glenohumeral abduction in the scapular plane. Testing was first performed on the normal shoulder state and was followed by the creation of a 20% posterior glenoid defect. Subsequently, the Kouvalchouk and DTA procedures were conducted. Forces of 0N, 5N, 10N and 15N were applied to the posterior deltoid tendinous insertion on the Kouvalchouk graft along the physiological muscle line-of-action to evaluate the ‘hammock” effect of this procedure. Testing was additionally performed on the Kouvalchouk bone graft with the deltoid muscle sectioned from its bony attachment. For all test states, a posteriorly directed force was applied to the humeral head perpendicular to the direction of the glenoid bone defect, with the associated translation quantified using an optical tracking system. The outcome variable was posterior translation of the humeral head at an applied force magnitude of 30N. ResultsThe Kouvalchouk procedure with the loaded deltoid flap (10N: P=0.039 and 15N: P<0.001) was significantly better at reducing posterior humeral head translation than the DTA. Overall, increased glenohumeral stability was observed with increased force applied to the posterior deltoid flap in the Kouvalchouk procedure. The 15N Kouvalchouk was most effective at preventing posterior humeral translation, and the difference was statistically significant compared with the 20% glenoid defect (P=0.003), detached Kouvalchouk (P<0.001), and 0N Kouvalchouk (P<0.001). The 15N Kouvalchouk procedure restored posterior shoulder joint stability to near normal levels, such that it was not significantly different from the intact state (P=0.203). ConclusionsThe Kouvalchouk procedure with load applied to the deltoid was found to be biomechanically superior to the DTA for the management of posterior shoulder instability with associated bone loss. Additionally, the results confirmed the presence and effectiveness of the deltoid “hammock” effect.

A modified virtual time reversal method for enhancing monitoring sensitivity of bolt preloads based on ultrasonic guided waves

Bolted joints are prone to loosening due to inaccurate initial preloads and time-varying service conditions. Real-time monitoring of bolt preloads is therefore an important means to warrant the reliability and safety of a bolted structure, though it remains a daunting task to implement precise monitoring of early bolt loosening. A modified virtual time reversal (MVTR) method is developed in this study, aimed at enhanced sensitivity of bolt preload monitoring. To begin with, the frequency response function (FRF) of an intact bolted structure is ascertained using the excitation wave and the received wave signal through the bolt. Then a received wave signal captured from the bolted structure under monitoring is time-reversed, and a refocused signal is calculated in virtue of the time-reversed signal and the FRF in the intact state. Bolt tightness indices are established by the peak amplitude or energy of the refocused wave packet. To facilitate interpretation of the principle of the proposed MVTR, a semi-analytic model is developed, which combines the waveform superposition method and finite element method. With the model, the effects of interface contact length, wave mode and signal frequency on the tightness indices are investigated. The effectiveness of the proposed MVTR is experimentally verified using three representative bolted lap structures featuring single bolt or multiple bolts. The results confirm the findings from the semi-analytic model, demonstrating that the MVTR enhances monitoring sensitivity compared to prevailing approaches using linear or nonlinear guided wave features.

Numerical analysis of a poroelastic cartilage model: Investigating the influence of changing material properties in osteoarthritis

Several changes occur in both the cartilage's material properties and anatomical structure as osteoarthritis progresses. Unlike most numerical studies that solely consider individual changes, our study aimed to understand the impact on cartilage mechanics by considering the combined effect of material properties and cartilage thickness varied with osteoarthritis progression. In total, 3 three-dimensional finite element models, representing the intact, early, and late osteoarthritis conditions, were developed to simulate a load-bearing area in the knee. The articular cartilage was modelled as fluid-saturated linear biphasic poroelastic to incorporate solid-fluid interaction. All models underwent prolonged creep (50 N) and relaxation (0.3 mm) analyses for 600 s. In the early stage of osteoarthritis, the tibial cartilage demonstrated an overall stiffer behaviour attributed to cartilage swelling despite decreased stiffness at the material level. On the other hand, in the late stage of osteoarthritis, the decrease in cartilage thickness led to increased knee deformation. Additionally, increased permeability resulted in accelerated fluid exudation across all osteoarthritis models, and the elevation in void ratio further intensified fluid pressure within the cartilage to a higher magnitude. Furthermore, these changes collectively influenced both the magnitude and distribution of the outcomes. A holistic understanding of the material properties altered in osteoarthritis may contribute to a better understanding of the mechanical performance of cartilage during disease progression.

Effect of confining pressure on the damage characteristics and mechanism of granite under ultra-high-frequency impact

Assisted ultra-high-frequency impact technology is a promising method for improving hard rock-breaking efficiency in geotechnical and petroleum engineering. However, previous studies did not consider the effects of in situ stress. In this study, triaxial ultra-high-frequency impact tests were conducted at confining pressures ranging from 0 to 20 MPa. Using nuclear magnetic resonance, infrared thermal radiation, crack dye penetrant, and scanning electron microscope tests, the influence of confining pressure on the macro, meso, and micro damage characteristics and mechanism of granite was revealed. The results indicate that with the increasing confining pressure, the porosity increment of small pores continuously decreases from 0.2% to −0.02%; the moderate pores first increase to a peak of around 0.18% before 6 MPa and then gradually decrease to around zero. The large pores began to increase after 8 MPa, increasing to around 0.05% when the confining pressure was 14 MPa. In addition, the failure mode first changed from tensile splitting damage to a relatively intact state with meso-damage, and finally, transverse shear fracture occurred owing to the higher shear stress and low mode II fracture toughness near the crack tips. These findings prove the effectiveness of ultra-high-frequency impact technology in weakening hard rock in deep strata.

The Effect of Lower Limb Alignment on Tibiofemoral Joint Contact Biomechanics after Medial Meniscus Posterior Root Repair: A Finite-Element Analysis.

The purpose of this study was to determine how variations in lower limb alignment affect tibiofemoral joint contact biomechanics in the setting of medial meniscus posterior root tear (MMPRT) and associated root repair. A finite-element model of an intact knee joint was developed. Limb alignments ranging from 4° valgus to 8° varus were simulated under a 1,000 N compression load applied to the femoral head. For the intact, MMPRT, and root repair conditions, the peak contact pressure (PCP), total contact area, mean and maximum local contact pressure (LCP) elevation, and total area of LCP elevation of the medial tibiofemoral compartment were quantified. The PCP and total contact area of the medial compartment in the intact knee increased from 2.43 MPa and 361 mm 2 at 4° valgus to 9.09 MPa and 508 mm 2 at 8° of varus. Compared with the intact state, in the MMPRT condition, medial compartment PCP was greater and the total contact area smaller for all alignment conditions. Root repair roughly restored PCPs in the medial compartment; however, this ability was compromised in knees with increasing varus alignment. Specifically, elevations in PCP relative to the intact state increased with increasing varus, as did the total contact area with LCP elevation. After root repair, medial compartment PCP remained elevated above the intact state at all degrees tested, ranging from 0.05 MPa at 4° valgus to 0.27 MPa at 8° of varus, with overall PCP values increasing from 2.48 to 9.09 MPa. For varus alignment greater than 4°, root repair failed to reduce the total contact area with LCP elevation relative to the MMPRT state. Greater PCPs and areas of LCP elevation in varus knees may reduce the clinical effectiveness of root repair in delaying or preventing the development of tibiofemoral osteoarthritis.

Effect of intramyocardial injection of allogeneic biomaterial on the exercise tolerance after destructive injury to the heart muscle (experimental study)

Introduction. The low regenerative potential of the heart prevents replacing dead cardiomyocytes with new cells. It has been shown that cell-free allogeneic biodegradable material (ABM) can increase the efficiency of reparative processes in myocardium and improve its structural and functional state. However, how the physical training capabilities change against this background has not been practically studied. Aim. To evaluate exercise tolerance in rats after the use of ABM. Material and methods. The work was performed on Wistar rats. Myocardial damage was caused by coronary occlusion (CO) and cryodestruction (CD) of the left ventricle apex of the heart. ABM was injected into the CO zone and along the perimeter of the myocardium affected area during CD. Animals with myocardial damage were included in control groups. Rats with myocardial damage and ABM injection constituted the experimental groups. Rats were taken into the experiment 45 days after ABM injection. The physical tolerance of rats was measured using the forced swimming test. Results. It has been shown that the swimming time of rats with СO by 62.5 % and with CD by 37.5 % (p&lt;0.05) is less compared to similar indicators for these animals in the initial (intact) state, which indicates a significant decrease in their exercise tolerance in myocardial damage. Animals with CO or CD on the background of intramyocardial injection of ABM showed 33 % and 48 % longer swimming during the test, respectively. The increase in exercise tolerance of rats against the background of the ABM administration was accompanied by the improvement in the morphometric parameters of the heart. Conclusion. The effect of ABM intramyocardial injection on the endogenous mechanisms of cardiac muscle regeneration is effective and functionally significant.

Dynamic Analysis of a Barge-Type Floating Wind Turbine Subjected to Failure of the Mooring System

Evidence points to increasing the development of floating wind turbines to unlock the full potential of worldwide wind-energy generation. Barge-type floating wind turbines are of interest because of their shallow draft, structural simplicity, and moonpool-damping effect. Based on the BEM potential flow method, this study uses ANSYS-AQWA software to create a floating-barge moonpool platform model equipped with an OC5 NREL 5 MW wind turbine, to study the effect of the damping lid method on the resonance of the moonpool gap water, the wind–wave coupling effect, and the dynamic response of the FOWT and mooring system after single-line and double-line failure. The results show that the damping lid method, based on the potential flow theory, can effectively correct the effect caused by the lack of viscosity; the effect of a single breakage of upwind mooring lines on the motion is mainly in the sway and yaw modes, and after mooring line 8 breaks, the maximum tension of the adjacent mooring line increases by 2.91 times compared to the intact condition, which is 58.9% of the minimum breaking strength; and the breakage of two mooring lines located at one corner leads to a surge drift of up to 436.7 m and a cascading failure phenomenon.

Effect of Distal Tibiofibular Destabilization and Syndesmosis Compression on the Flexibility Kinematics of the Ankle Bones: An In Vitro Human Cadaveric Model.

Overcompression of the distal tibiofibular syndesmosis during open reduction and internal fixation of ankle fracture may affect multidirectional flexibility of the ankle bones. Ten cadaveric lower limbs (78.3±13.0 years, 4 female, 6 male) underwent biomechanical testing in sagittal, coronal, and axial rotation with degrees of motion quantified. The intact force (100%) was the force needed to compress the syndesmosis just beyond the intact position, and overcompression was defined as 150% of the intact force. After intact testing, the anterior inferior tibiofibular ligament (AITFL), interosseus membrane (IOM), and posterior inferior tibiofibular ligament (PITFL) were sectioned and testing was repeated. The IOM and AITFL were reconstructed in sequence and tested at 100% and 150% compression. Overcompression of the syndesmosis did not significantly reduce ROM of the ankle bones for any loading modality (P > .05). IOM+AITFL reconstruction restored distal tibiofibular axial rotation to the intact condition. Axial rotation motion was significantly lower with AITFL fixation compared with IOM fixation alone (P < .05). The proximal tibiofibular syndesmosis demonstrated significantly higher motion in axial rotation with all distal reconstruction conditions. As assessed by direct visualization, overcompression of the distal tibiofibular syndesmosis did not reduce ROM of the ankle bones. Distal tibiofibular axial rotation was significantly lower with IOM+AITFL fixation compared with IOM augmentation alone. Distal tibiofibular axial rotation did not differ significantly from the intact condition after combined IOM+AITFL fixation. Dynamic fixation of the distal tibiofibular syndesmosis resulted in increased axial rotation at the proximal tibiofibular syndesmosis. These biomechanical data suggest that inadvertent overcompression of the distal tibiofibular syndesmosis when fixing ankle fractures does not restrict subsequent ankle bone ROM. The AITFL is an important stabilizer of the distal tibiofibular syndesmosis in external rotation. controlled laboratory study.

Effect of temperature rise on the mechanical behaviour of deep-sea clay surrounding oil and gas pipelines

The mechanical behaviour of deep-sea clay is crucial for oil and gas pipeline safety and is traditionally assessed through in situ penetration testing, which is usually conducted in a low-temperature environment (usually at temperatures lower than 4 °C). However, the temperature of deep-sea clay surrounding high-temperature pipelines can reach approximately 20 °C. To date, the influence of temperature variation on the mechanical properties of deep-sea clay, especially strain-softening behaviour, has been largely overlooked, posing a safety risk to practical engineering. Consequently, this study first establishes a temperature-controlled cyclic penetration testing platform. Then, an enhanced mini-spherical penetrometer is employed to investigate the undrained strength and strain-softening behaviour of undisturbed deep-sea clay samples at 4 °C, 10 °C and 20 °C. In particular, an improved framework is proposed to quantitatively characterize the mechanical behaviour. Finally, a strain-softening law considering temperature variations is established and rigorously validated through in situ tests. The findings underscore several significant observations: (a) deep-sea clay in its intact state exhibits a heightened sensitivity to temperature variations compared to that in its remoulded state; (b) temperature variations influence the strain-softening parameters of deep-sea clay, resulting in distinct behaviours; and (c) the proposed strain-softening law considering temperature variations is verified to be more logical.

Peculiarities of property rights protection, their specific application to objects

The article examines the issue of the specifics of the protection of property rights, the specifics of their application to objects.&#x0D; Article 13 of the Constitution of Ukraine declares that the fundamental principle of in the field of protection of property rights there is a provision that the state provides equal protection of all subjects of property rights. In recent years, the question of protection of property rights has gained important theoretical and practical importance. The analysis of modern judicial practice shows that there is no unified position of judicial bodies on the resolution of disputes related to the violation of property rights. Courts of general jurisdiction and commercial courts, when considering disputes related to the protection of violated rights, ambiguously apply the norms of current legislation, therefore, the uncertainty of judicial authorities in the matter of the uniform application of the provisions of civil law to disputes of this category leads to the violation of the constitutional rights of owners.&#x0D; It is emphasized that the protection of property rights is a complex of civil legal means, which are aimed, on the one hand, at ensuring the normal economic use of property and maintaining property rights in an intact state, and, on the other hand, at restoring violated property relations, overcoming obstacles to their normal functioning and compensation for damages caused to the owner.&#x0D; As a conclusion, it is said that the protection of property rights acts as an independent subjective right that arises at the moment when there is a threat of its violation or dispute. This right includes powers, each of which involves the active implementation of positive actions.&#x0D; In the field of legal relations related to the protection of property rights, the objects of protection are directly the rights to certain objects. It is these rights that can be violated by other persons, and it is for their protection that the civil law provides for various means that a person can use to protect his violated or disputed rights, which are subject to protection by the law of interests.&#x0D; Subjects of legal relations related to the protection of property rights are, on the one hand, persons who have property rights to a specific object, and persons who retain property in accordance with relevant contracts or laws, and who, accordingly to legal norms, have the right to demand protection of their violated subjective rights. On the other hand, these are persons whose actions led to the unlawful violation of subjective rights to property objects.

Analyzing isolated degeneration of lumbar facet joints: implications for degenerative instability and lumbar biomechanics using finite element analysis.

The facet joint contributes to lumbar spine stability as it supports the weight of body along with the intervertebral discs. However, most studies on the causes of degenerative lumbar diseases focus on the intervertebral discs and often overlook the facet joints. This study aimed to investigate the impact of facet joint degeneration on the degenerative changes and diseases of the lumbar spine. A finite element model of the lumbar spine (L1-S1) was fabricated and validated to study the biomechanical characteristics of the facet joints. To simulate degeneration of the facet joint, the model was divided into four grades based on the number of degenerative segments (L4-L5 or L4-S1) and the contact condition between the facet joint surfaces. Finite element analysis was performed on four spine motions: flexion, extension, lateral bending, and axial torsion, by applying a pure moment to the upper surface of L1. Important parameters that could be used to confirm the effect of facet joint degeneration on the lumbar spine were calculated, including the range of motion (ROM) of the lumbar segments, maximum von Mises stress on the intervertebral discs, and reaction force at the facet joint. Facet joint degeneration affected the biomechanical characteristics of the lumbar spine depending on the movements of the spine. When analyzed by dividing it into degenerative onset and onset-adjacent segments, lumbar ROM and the maximum von Mises stress of the intervertebral discs decreased as the degree of degeneration increased in the degenerative onset segments. The reaction force at the facet joint decreased with flexion and increased with lateral bending and axial torsion. In contrast, lumbar ROM of the onset-adjacent segments remained almost unchanged despite severe degeneration of the facet joint, and the maximum von Mises stress of the intervertebral discs increased with flexion and extension but decreased with lateral bending and axial torsion. Additionally, the facet joint reaction force increased with extension, lateral bending, and axial rotation. This analysis, which combined the ROM of the lumbar segment, maximum von Mises stress on the intervertebral disc, and facet joint reaction force, confirmed the biomechanical changes in the lumbar spine due to the degeneration of isolated facet joints under the load of spinal motion. In the degenerative onset segment, spinal instability decreased, whereas in the onset-adjacent segment, a greater load was applied than in the intact state. When conducting biomechanical studies on the lumbar spine, considering facet joint degeneration is important since it can lead to degenerative spinal diseases, including adjacent segment diseases.

Biomechanical Comparison Between Superior Capsular Reconstruction and Lower Trapezius Tendon Transfer in Irreparable Posterosuperior Rotator Cuff Tears

Background: Superior capsular reconstruction (SCR) and lower trapezius tendon transfer (LTT) have recently been used to manage irreparable posterosuperior rotator cuff tears (PSRCTs). There has been a paucity of comparative biomechanical considerations between the 2 procedures. Purpose: To compare the glenohumeral stability and biomechanical properties between SCR and LTT in PSRCTs involving the entire infraspinatus tendon region. Study Design: Controlled laboratory study. Methods: Eight fresh-frozen cadaveric shoulders were tested at 0°, 20°, and 40° of shoulder abduction. Maximum internal, external, and total humeral range of motion (ROM), superior translation of the humeral head, and subacromial contact characteristics were compared among 4 conditions: (1) intact rotator cuff, (2) PSRCTs involving the entire infraspinatus tendon region, (3) LTT using Achilles allograft (12 N and 24 N of loading), and (4) SCR using fascia lata allograft. Results: Although a decrease in total ROM was noted in LTT with 12 N compared with the tear condition, LTT with both 12 N and 24 N as well as SCR did not restrict total rotational ROM compared with the intact condition. LTT had decreased total ROM compared with tear condition at 20° of abduction (P = .042), while no significant decrease was confirmed at all abduction angles after SCR. SCR and LTT with 24 N decreased superior translation compared with the PSRCT condition at 0° and 20° of abduction (P < .037) but not significantly at 40° of abduction, whereas LTT with a 24-N load decreased glenohumeral superior translation at all abduction angles (P < .039). Both SCR and LTT decreased subacromial contact pressure compared with the tear condition (P < .014) at all abduction angles. SCR decreased subacromial contact pressure at 0° and 40° of abduction (P = .019 and P = .048, respectively) compared with LTT with 12 N of loading, while there was no difference between SCR and LTT with 24 N of loading in all abduction angles. SCR increased the contact area compared with the PSRCT condition at all abduction angles (P < .023), whereas LTT did not increase the contact area. Conclusion: SCR and LTT decreased glenohumeral superior translation and contact pressure compared with PSRCT conditions. The LTT was superior to SCR in terms of superior translation of the humeral head at a higher shoulder abduction angle, whereas the SCR showed more advantageous subacromial contact characteristics compared with LTT. Clinical Relevance: These biomechanical findings provide insights into these 2 fundamentally different procedures for the treatment of young and active patients with PSRCTs involving the entire infraspinatus tendon region.

Time-elapsed microstructural imaging of failure of the reverse shoulder implant

BackgroundReverse Shoulder Arthroplasties (RSA) have become a primary choice for improving shoulder function and pain. However, the biomechanical failure mechanism of the humeral component is still unclear. The present study reports a novel protocol for microstructural imaging of the entire humerus implant under load before and after fracture.MethodsA humerus specimen was obtained from a 75-year-old male donor. An expert surgeon implanted the specimen with a commonly used RSA implant (Aequalis reversed II, Stryker Orthopaedics, USA) and surgical procedure. The physiological glenohumeral contact force that maximized the distal implant migration was selected from a public repository (orthoload.com). Imaging and concomitant mechanical testing were performed using a large-volume micro-CT scanner (Nikon XT H 225 ST) and a custom-made compressive stage. Both when intact and once implanted, the specimen was tested under a pre-load and by imposing a constant deformation causing a physiological reaction load (650 N, 10 degrees adducted). The deformation of the implanted specimen was then increased up to fracture, which was identified by a sudden drop of the reaction force, and the specimen was then re-scanned.ResultsThe specimen’s stiffness decreased from 874 N/mm to 464 N/mm after implantation, producing movements of the bone-implant interface consistent with the implant’s long-term stability reported in the literature. The micro-CT images displayed fracture of the tuberosity, caused by a combined compression and circumferential tension, induced by the distal migration of the implant.ConclusionThe developed protocol offers detailed information on implant mechanics under load relative to intact conditions and fracture, providing insights into the failure mechanics of RSA implants. This protocol can be used to inform future implant design and surgical technique improvements.