Search Results (75)

A new class of poroelastic dynamic contact problems stemming from hydraulic fracture theory is introduced and studied. The two-phase medium consists of a solid phase and pores which are saturated with a Newtonian fluid. The porous body contains a fluid-driven crack endowed with non-penetration conditions for the opposite crack surfaces. The poroelastic model is described by a coupled system of hyperbolic–parabolic partial differential equations under the unilateral constraint imposed on displacement. After full discretization using finite-element and Hilber–Hughes–Taylor methods, the well-posedness of the resulting variational inequality is established. Formulation of the complementarity conditions with the help of a minimum-based merit function is used for the semi-smooth Newton method of solution presented in the form of a primal–dual active set algorithm which is tested numerically. Full article

Bit-related trauma is a welfare issue in equestrian sports; therefore, a proper understanding of how the bit behaves inside the mouth is of importance. The objective of this study is to investigate the influence of bit design (snaffle bits/single/double-jointed; ring/eggbutt and curb bits), size, rein tension, and rein angle on the intra-oral movement of the bit in ex vivo specimens. The lateral and posterior movement of different bits was measured on cadaver heads under different circumstances. This ex vivo model, while not fully replicating natural conditions, provided insight into potential bit-related movements. Lateral displacement of the snaffle bit was significantly greater with higher unilateral rein tension. Bits that were too wide exhibited significantly more lateral and posterior displacement under unilateral rein tension. Posterior displacement increased with both unilateral and bilateral rein tensions. Using a bit that is too wide, using reins at a 20° angle, and applying 4 kg of rein tension were identified as risk factors for contact with the mesial gingival tissues of the mandibular 06s. Similar patterns were observed with curb bits, although bit movement was more restricted, and no contact with the mesial gingival tissues of the mandibular 06s was noted. This study demonstrated that bit design, bit size, rein angle, and rein tension all influence bit movement in the horse’s mouth. Full article

Corneal sequestrum, also known as corneal mummification or necrosis, is a common complication of corneal ulceration in cats, with brachycephalic and pure-bred cats being the most affected. This prospective clinical trial aimed to evaluate the efficacy of self-adhesive, human bandage contact lenses (SHBCLs) versus the commonly used conjunctival transposition flap (CTF) in the management of feline corneal sequestrum. Twenty-five client-owned cats of different breeds with unilateral corneal sequestrum were investigated. All cats underwent a complete ophthalmic examination. Characterization of corneal sequestrum was carried out. The corneal lesion was removed surgically via keratectomy, and the cats were then categorized into three treatment groups: G-SHBCL (10 cats), G-CTF (10 cats), and the control group (G-CO, 5 cats). The healing progress of the corneal defect and associated clinical findings were recorded in all studied groups. Eight out of ten cats (80%) treated with SBCLs showed complete healing of the corneal defect with light corneal scarring and absence of all signs of ocular pain or discomfort. In comparison with G-CTF and G-CO, no granulation tissue was observed in all cats treated with SHBCLs. Moreover, no residues of corneal sequestrum or adhesion were identified, and the degree of corneal clarity was higher in the SHBCL treatment group. In conclusion, application of SHBCLs on a corneal defect, after removal of the associated sequestrum, enhances healing of the cornea and markedly improves the corneal clarity and transparency within a short period. Full article

Background/Objectives: Temporomandibular disorders (TMDs) are a group of musculoskeletal and neuromuscular conditions involving the temporomandibular joint (TMJ), masticatory muscles, and related anatomical structures. Although magnetic resonance imaging (MRI) is considered a noninvasive and highly informative imaging modality for assessing TMJ soft tissues, few studies have examined how TMJ structural features observed on MRI findings relate to oral function and craniofacial morphology in female patients with malocclusion. To investigate the associations among TMJ structural features, oral function, and craniofacial morphology in female patients with malocclusion, using MRI findings interpreted in conjunction with a preliminary assessment based on selected components of the DC/TMDs Axis I protocol. Methods: A total of 120 female patients (mean age: 27.3 ± 10.9 years) underwent clinical examination based on DC/TMDs Axis I and MRI-based structural characterization of the TMJ. Based on the structural features identified by MRI, patients were classified into four groups for comparison: osteoarthritis (OA), bilateral disk displacement (BDD), unilateral disk displacement (UDD), and a group with Osseous Change/Disk Displacement negative (OC/DD (−)). Occlusal contact area, occlusal force, masticatory efficiency, tongue pressure, and lip pressure were measured. Lateral cephalometric analysis assessed skeletal and dental patterns. Results: OA group exhibited significantly reduced occlusal contact area (p < 0.0083, η² = 0.12) and occlusal force (p < 0.0083, η² = 0.14) compared to the OC/DD (−) group. Cephalometric analysis revealed that both OA and BDD groups had significantly larger ANB angles (OA: 5.7°, BDD: 5.2°, OC/DD (−): 3.7°; p < 0.0083, η² = 0.21) and FMA angles (OA: 32.4°, BDD: 31.8°, OC/DD (−): 29.0°; p < 0.0083, η² = 0.17) compared to the OC/DD (−) group. No significant differences were observed in masticatory efficiency, tongue pressure, or lip pressure. Conclusions: TMJ structural abnormalities detected via MRI, especially osteoarthritis, are associated with diminished oral function and skeletal Class II and high-angle features in female patients with malocclusion. Although orthodontic treatment is not intended to manage TMDs, MRI-based structural characterization—when clinically appropriate—may aid in treatment planning by identifying underlying joint conditions. Full article

Vestibular atelectasis (VA) is a rare clinical entity characterized by a collapse of the endolymphatic space resulting in vestibular loss with the possible onset of positional and/or sound/pressure-induced vertigo. It could be idiopathic or secondary to other inner-ear diseases including Meniere’s disease (MD). A collapse of the membranous labyrinth involving the semicircular canals (SCs) and the utricle represents its distinctive histopathological feature. While specific radiological patterns consistent with VA have been described on contrast-enhanced MRI with delayed acquisitions, an impairment of the blood–labyrinthine barrier (BLB) could be detected in several disorders leading to vestibular loss. We conducted a narrative review of the literature on VA focusing on the putative pathomechanisms accounting for positional and sound/pressure-induced nystagmus despite unilateral vestibular loss (UVL) in this condition, providing two novel cases of VA. Both patients presented with a clinical picture consistent with unilateral MD that rapidly turned into progressive UVL and positional and/or sound/pressure-induced vertigo. In both cases, the posterior SC was initially impaired at the video-head impulse test (vHIT) and both cervical and ocular VEMPs were initially reduced. Progressively, they developed unsteadiness with paretic spontaneous nystagmus, an impairment also for the lateral and anterior SCs, caloric hypo/areflexia and VEMPs areflexia. They both exhibited ipsilesional nystagmus to sound/pressure stimuli and in one case a persistent geotropic direction-changing positional nystagmus consistent with a “light cupula” mechanism involving the lateral SC of the affected side. A collapse of the membranous labyrinthine walls resulting in contact between the vestibular sensors and the stapes footplate could explain the onset of nystagmus to loud sounds and/or pressure changes despite no responses to high- and low-frequency inputs as detected by caloric irrigations, vHIT and VEMPs. On the other hand, the onset of positional nystagmus despite UVL could be explained with the theory of the “floating labyrinth”. Both patients received contrast-enhanced brain MRI with delayed acquisition exhibiting increased contrast uptake in the pars superior of the labyrinth, suggesting an impairment of the BLB likely resulting in secondary VA. A small intralabyrinthine schwannoma was detected in one case. VA should always be considered in case of positional and/or sound/pressure-induced vertigo despite UVL. Full article

Background: Anterior cruciate ligament (ACL) injuries are a major concern in female soccer players, with change of direction (COD) movements being a key contributor to non-contact injuries. Traditional injury prevention programs have shown limited effectiveness in addressing individual biomechanical deficits. This study aimed to evaluate the effects of a 10-week unilateral strength training program on COD mechanics and ACL injury risk factors. Methods: Eleven female soccer players participated in a pre–post intervention study. Movement mechanics was assessed using the Cutting Movement Assessment Score (CMAS) at 45°, 75°, and 90° angles. The training program included unilateral lower limb strengthening exercises designed to enhance neuromuscular control and reduce biomechanical risk factors. Risk profiles were analyzed before and after the intervention. Statistical analyses included paired t-tests and effect size calculations. Results: Significant improvements in CMAS scores were observed at all COD angles (p < 0.05), with the largest effect at 90° (Cohen’s d = 2.1). The percentage of high-risk players decreased from 82% to 0%, while the proportion of low-risk players increased from 36% to 73%. Improved knee alignment, foot placement, and trunk stability were key contributors to the observed movement enhancements. Conclusions: Unilateral strength training may effectively improve COD mechanics and reduces biomechanical risk factors associated with ACL injuries in female soccer players. Our findings suggest that individualized training interventions can influence current injury prevention strategies. Full article

This study investigates the acute effects of a combined isometric and plyometric unilateral conditioning activity (CA) on post-activation performance enhancement (PAPE) in junior elite sprinters. The rationale for combining isometric and plyometric exercises lies in their complementary effects: isometric exercises enhance neuromuscular activation, while plyometric exercises may exploit the stretch–shortening cycle to maximize power output. Thirteen sprinters (10 males, three females) performed countermovement jumps (CMJ) and 50 m sprints before and after the CA protocol, which involved Bulgarian split squats (15% body mass) and single-leg hops. Performance metrics, including sprint times, CMJ height, and modified reactive strength index (RSImod), were recorded and analyzed. Results showed a significant improvement in CMJ height (2.6 ± 3.1%, p < 0.001) and RSI (4.1 ± 7.5%, p = 0.038), alongside a reduction in 20 m sprint time (−0.8 ± 1.4%, p = 0.012). No significant changes were observed in 40 m and 50 m sprint times or ground contact and flight times. These findings suggest that the applied CA selectively enhances sprint acceleration and vertical jumping performance, with a minimal impact on sprint distances above 20 m. This study underscores the potential of incorporating combined isometric and plyometric CAs into sprint training to optimize short-distance performance, though further research is needed to refine exercise protocols and explore long-term effects. Full article

The diagnosis of patellofemoral pain (PFP) remains imprecise due to the variable sensitivity and specificity scores of most clinical tests. More functionally relevant assessments and metrics are needed to provide better diagnostic insights. A total of 33 participants (control: n = 17 [M/F = 9/7]; PFP: n = 18 [M/F = 2/14]) volunteered for this study. The control group followed no intervention program, whereas the PFP group completed a joint-specific intervention program at a clinical practice for 8 weeks. At 0- and 8-week isometric knee extensor torques, unilateral drop jumping metrics, and anterior knee pain scale (AKPS) scores were collected and analysed. Statistically significant between-group differences were evident for the reactive strength index (RSI) (M_diff = 0.05 m/s, p = 0.032) and ground contact time (GCT) (M_diff = 0.28 s, p = 0.011) but not for peak force (p = 0.390), jump height (p = 0.721), impulse (p = 0.740), or peak torque (p = 0.359). While controlling for gender as a confounder, the RSI and GCT showed diagnostic utility for differentiating PFP from healthy controls (AUC = 0.83–0.87, sensitivity = 0.85–0.91, and specificity = 0.59–0.72). The AKPS score demonstrated moderate positive correlations with jump metrics (impulse: r = 0.58, 95% confidence interval (CI) [0.11, 0.83]; RSI: r = 0.50, 95% CI [0.01, 0.80]), accounting for 25–34% of performance variability. The unilateral drop jump provides useful metrics for differentiating those with PFP from their healthy counterparts. The RSI and GCT may serve as diagnostic metrics in evaluating PFP patients and can be coupled with the AKPS to track performance and rehabilitation progress in PFP patients. Full article

Background/Objectives: This study investigated the impacts of a 12-week training program on kinetic parameters during landings in non-professional recreational athletes. Methods: Fifty-seven non-elite recreational athletes performed three unilateral-landing trials from a 30 cm high structure on a force platform. The following outcome measures were analyzed: the ground reaction forces at initial ground contact (PF1) and the highest value (PF2), impulse (change in the moment of force during landing), stabilization time, and ankle and knee accelerations. The ground reaction forces, momentum, and accelerations were evaluated in the vertical, medio-lateral, and anteroposterior axes. Participants were randomly assigned to two groups. The experimental group (EG) underwent a 12-week intervention, three times per week, consisting of various exercises, such as strength, eccentric, proprioceptive, whole-body vibration (WBV), and neuromuscular exercises. After 12 weeks, the same outcome measures were analyzed. Results: The effects of the training program on vertical ground reaction forces were not clear (0.3% and 0.9%, respectively). Medio-lateral (64.8%, d = 0.51) and anteroposterior (43.9%, d = 1.34) forces were probably reduced due to the training program. The stabilization time was also reduced in the experimental group (44.2%). The training program most likely decreased the vertical impulse (47.3%, d = −1.56), whereas the total ankle acceleration increased (18.4%, d = 0.79). Conclusions: The findings reveal significant improvements in neuromuscular control and stability during landings, specifically demonstrating reduced medio-lateral forces, vertical momentum, and acceleration during monopodal landings. This study focuses on the importance of proper landing techniques in minimizing the risk of knee injuries, emphasizing the falling strategy’s role in injury prevention. Full article

Spinal cord injury results in significant motor and sensory loss. In the experimental ventral root avulsion (VRA) model, the ventral (motor) roots are disconnected from the spinal cord surface, disrupting contact between spinal motoneurons and muscle fibers. Axotomized motoneurons typically degenerate within two to three weeks after avulsion, the situation being exacerbated by an increased glial response and chronic inflammation. Nevertheless, root reimplantation has been observed to stimulate regenerative potential in some motoneurons, serving as a model for CNS/PNS regeneration. We hypothesized that a combination of neuroprotective and immunomodulatory therapies is capable of enhancing regenerative responses following nerve root injury and repair. A heterologous fibrin biopolymer (HFB) was used for surgical repair; dimethyl fumarate (DMF) was used for neuroprotection and immunomodulation; and adipose tissue-derived mesenchymal stem cells (AT-MSCs) were used as a source of trophic factors and cytokines that may further enhance neuronal survival. Thus, adult female Lewis rats underwent unilateral VRA of the L4–L6 roots, followed by reimplantation with HFB, AT-MSCs transplantation, and daily DMF treatment for four weeks, with a 12-week postoperative survival period. An evaluation of the results focused on light microscopy, qRT-PCR, and the Catwalk motor function recovery system. Data were analyzed using one-way or two-way ANOVA (p < 0.05). The results indicate that the combined therapy resulted in a reduced glial response and a 70% improvement in behavioral motor recovery. Overall, the data support the potential of combined regenerative approaches after spinal cord root injury. Full article

We consider an elliptic variational–hemivariational inequality $\mathcal{P}$ in a real reflexive Banach space, governed by a set of constraints K. Under appropriate assumptions of the data, this inequality has a unique solution $u\in K$. We associate inequality $\mathcal{P}$ to a sequence of elliptic variational–hemivariational inequalities $\left\{{\mathcal{P}}_n\right\}$, governed by a set of constraints $\tilde{K}\supset K$, a sequence of parameters $\left\{{\lambda }_n\right\}\subset {\mathbb{R}}_{+}$, and a function $\psi$. We prove that if, for each $n\in \mathbb{N}$, the element $u_n\in \tilde{K}$ represents a solution to Problem ${\mathcal{P}}_n$, then the sequence $\left\{u_n\right\}$ converges to u as ${\lambda }_n\to 0$. Based on this general result, we recover convergence results for various associated penalty methods previously obtained in the literature. These convergence results are obtained by considering particular choices of the set $\tilde{K}$ and the function $\psi$. The corresponding penalty methods can be applied in the study of various inequality problems. To provide an example, we consider a purely hemivariational inequality that describes the equilibrium of an elastic membrane in contact with an obstacle, the so-called foundation. Full article

Background: Preserving residual hearing after cochlear implant (CI) surgery remains a crucial challenge. The application of dexamethasone (DEX) has been proven to positively affect residual hearing. To deliver DEX in a localized and controlled way, a round window niche implant (RNI), allowing drug diffusion via the round window membrane into the cochlea, may be used. To prove this concept, an RNI for guinea pigs as a CI-trauma model was manufactured by molding and tested for its drug release in vitro and biological effects in vivo. Methods: The RNIs were molded using silicone containing 10% DEX. Release was analyzed over time using high-performance liquid chromatography (HPLC). Fourteen adult guinea pigs were randomly assigned to two groups (CI or CI + RNI group). All animals received a unilateral CI electrode insertion trauma followed by CI insertion. The CI + RNI group was additionally implanted with an RNI containing 10% DEX. Animals were followed up for 4 weeks. Acoustically evoked auditory brainstem response and impedance measurement, micro-computed tomography (µCT) imaging, and histology were performed for evaluation. Results: DEX was released for more than 250 days in vitro, with an initial burst followed by a slower release over time. Comparing the hearing threshold shift (from day 0 to day 28) of the CI and CI + RNI groups, significant differences were observed at 32 and 40 kHz. The impedance shift at basal contacts was lower in the CI + RNI group than in the CI group. Moreover, the fibrosis in the lower basal turn was reduced in the CI + RNI group in contrast to the CI group. Conclusions: The RNI containing 10% DEX has anti-inflammatory potential concerning fibrosis inhibition and has beneficial effects on hearing preservation at high frequencies. Full article

The existing PDC (polycrystalline diamond compact)–cone hybrid bit bearing adopts a unilateral support structure, which is prone to stress concentration in the journal area, resulting in fracture and wear failure of the bearing, thus reducing the service life of the hybrid bit. In this paper, a new type of double supported bearing hybrid bit is proposed. The static strength analysis of unilateral and bilateral support bearing structures is carried out by finite element simulation, and the stress and strain distribution of the two structures under loads of 20–100 kN is obtained. Experimental devices for unilateral and bilateral support bearing structures are designed and manufactured to complete 50–100 kN static pressure loading experiments. The results show that the stress and strain of unilateral and bilateral support bearing increased linearly with the increase of load. Compared with unilateral bearing, when the load was 100 kN, the maximum Mises stress of bilateral bearing decreased from 358.80 MPa to 211.10 MPa, with a decrease of 41.16%. The maximum contact stress decreased from 415.20 MPa to 378.10 MPa, a decreased of 8.94%, and the maximum principal strain decreased from 1.101 × 10⁻³ to 9.71 × 10⁻⁴, a decrease of 11.81%. The axial strain in the danger zone was reduced by 14.68% and 17.35%, respectively. It is found that the contact stress of the simulation data is highly correlated with the bearing life, and the service life of the bilateral bearing bit is increased by 8.94%. The simulation data and experimental results provide data support for the production of hybrid bits with bilateral bearing support. Full article

Traditional measurement methods often rely on manual operations, which are not only inefficient but also cause stress to cattle, affecting animal welfare. Currently, non-contact cattle dimension measurement usually involves the use of multi-view images combined with point cloud or 3D reconstruction technologies, which are costly and less flexible in actual farming environments. To address this, this study proposes an automated cattle dimension measurement method based on an improved keypoint detection model combined with unilateral depth imaging. Firstly, YOLOv8-Pose is selected as the keypoint detection model and SimSPPF replaces the original SPPF to optimize spatial pyramid pooling, reducing computational complexity. The CARAFE architecture, which enhances upsampling content-aware capabilities, is introduced at the neck. The improved YOLOv8-pose achieves a mAP of 94.4%, a 2% increase over the baseline model. Then, cattle keypoints are captured on RGB images and mapped to depth images, where keypoints are optimized using conditional filtering on the depth image. Finally, cattle dimension parameters are calculated using the cattle keypoints combined with Euclidean distance, the Moving Least Squares (MLS) method, Radial Basis Functions (RBFs), and Cubic B-Spline Interpolation (CB-SI). The average relative errors for the body height, lumbar height, body length, and chest girth of the 23 measured beef cattle were 1.28%, 3.02%, 6.47%, and 4.43%, respectively. The results show that the method proposed in this study has high accuracy and can provide a new approach to non-contact beef cattle dimension measurement. Full article

Cat-scratch disease (CSD) is an infectious disease caused by Bartonella henselae, presenting with fever and lymphadenopathy following contact with felines. The ocular manifestations include neuroretinitis, characterised by optic nerve swelling and a macular star. Case Presentation: We discuss a case of neuroretinitis that presented atypically, without a macular star. There was an initial suspicion of Bartonella, but the serology was negative. Our patient was eventually empirically treated for infective neuroretinitis based on a positive contact history (recently scratched by one of his three pet cats). There was progression to a macular star upon serial dilated fundus examination, and the repeated serology one week after symptom onset showed rising titres, supporting a diagnosis of CSD. Conclusions: A judicious review of systems, repeat assays, serial dilated fundus examination, and early ophthalmic evaluation are useful in cases of suspected neuroretinitis, remaining an important differential in the evaluation of sudden-onset painless vision loss and unilateral disc swelling. Full article