Search Results (35)

Background/Objectives: Patellar instability in adolescents is a significant cause of short- and long-term morbidity and disability. Traditionally, patients with first-time patellar dislocation are managed nonoperatively, although most studies are not focusing on the adolescent athletic population. The primary objective of the current study was to compare patient-reported outcomes and complications in adolescent athletes who underwent surgery either after the first patellar dislocation or after the recurrence of the dislocation with a minimum postoperative follow-up of 48 months (48–75 months). Methods: A total of 39 adolescent athletes who underwent medial patellofemoral ligament (MPFL) reconstruction (Group A, after the first dislocation, and Group B, recurrent patella dislocation) were included in this study. In all the patients, the same MPFL reconstruction technique was applied using a semitendinosus autograft. The graft was fixed on the patella using a transverse tunnel and adjustable loop button fixation and, in the femur, using a tunnel and absorbable screw fixation. The tunnel was drilled obliquely to prevent penetration of the distal femoral physis. The preoperative and postoperative clinical and functional evaluations of the patients were conducted via the visual analog scale (VAS), the Lysholm Knee Scoring System, the Kujala Anterior Knee Pain Scale, and the Pediatric International Knee Documentation Committee (Pedi-IKDC), and the return to sports score was assessed via the Tegner Activity Scale (TAS). Results: At the latest follow-up, both groups demonstrated significant improvement in the Lysholm scores, with Group A achieving a mean of 92.57 ± 6.21 and Group B achieving a mean of 90.53 ± 8.21 (p = 0.062). Postoperatively, Group A achieved a mean Kujala score of 94.21 ± 9.23, whereas Group B reached 92.76 ± 12.39, with no statistically significant difference (p = 0.08). The Pedi-IKDC score improved postoperatively in both groups. In Group A, it increased from 67.98 ± 12.29 to 93.65 ± 4.1, and in Group B, from 56.21 ± 13.6 to 91.67 ± 6.21 (p = 0.067). The preoperative visual analog scale (VAS) score for pain was significantly lower in Group A (3.1 ± 1.13) than in Group B (4.2 ± 3.01, p < 0.01). At the latest follow-up, the VAS scores improved in both groups, with Group A reporting a mean score of 0.47 ± 1.01 and Group B 0.97 ± 1.32 (p = 0.083). The Tegner activity scores were similar between the groups preoperatively, with Group A at 7.72 ± 1.65 and Group B at 7.45 ± 2.09 (p = 0.076). Postoperatively, Group A had a mean score of 7.28 ± 2.15, whereas Group B had a mean score of 6.79 ± 3.70 (p = 0.065). The mean time to return to sports was significantly shorter in Group A (5.1 ± 1.3 months) than in Group B (7.6 ± 2.1 months) (p < 0.01). Overall, 84.61% of the patients returned to their previous activity level. Specifically, 95.2% (20/21) of patients in Group A achieved this outcome, whereas 72.22% (13/18) achieved it in Group B. Patient satisfaction was generally high, with 76% (16/21) of patients in Group A reporting being satisfied or very satisfied, compared with 77% (14/18) in Group B. Conclusions: MPFL reconstruction is a safe and effective procedure for both acute and recurrent patellar dislocation in adolescent athletes. While patients who underwent acute reconstruction returned to sport more quickly and showed higher absolute postoperative scores, the greatest overall improvement from preoperative to final follow-up was observed in those treated for recurrent instability. Both surgical approaches demonstrated high satisfaction rates and minimal complications, supporting MPFL reconstruction as a reliable option in both acute and recurrent cases. Full article

Reinforced concrete structures are prone to the development of microcracks during service. In this study, a composite-modified epoxy potting adhesive was formulated using nano-TiO₂, carboxyl-terminated butadiene nitrile liquid rubber (CTBN), and the reactive diluent D-669. The mechanical properties and effectiveness of this composite adhesive in repairing oblique cracks were systematically evaluated and compared with those of single-component-modified epoxy adhesives. Key material parameters influencing the performance of oblique crack repair were identified, and the underlying repair mechanisms were analyzed. Based on these findings, a theoretical formula for calculating the shear-bearing capacity of beams with repaired web reinforcement was proposed. Experimental results demonstrated that compared to single-component-modified epoxy resin, the optimally formulated composite adhesive improved the tensile strength, elongation at break, and bond strength by 4.07–21.16 MPa, 13.28–20.4%, and 1.05–3.79 MPa, respectively, while reducing the viscosity by 48–872 mPa·s. The viscosity of the adhesive was found to play a critical role in determining the repair effectiveness, with toughness enhancing the crack resistance and bond strength contributing to the structural stiffness recovery. The adhesive effectively penetrated the steel–concrete interface, forming a continuous bonding layer that improved energy dissipation and significantly enhanced the load-bearing capacity of the repaired beams. Full article

Unmanned aerial vehicles (UAVs) are rapidly becoming a popular tool for digital soil mapping at a large-scale. However, their applicability in areas with homogeneous vegetation (i.e., not bare soil) has not been fully investigated. In this study, we aimed to predict soil organic carbon, soil texture at several depths, as well as the thickness of the AB soil horizon and penetration resistance using a machine learning algorithm in combination with UAV images. We used an area in the Eurasian steppe zone (Republic of Bashkortostan, Russia) covered with the Stipa vegetation type as a test plot, and collected 192 soil samples from it. We estimated the models using a cross-validation approach and spatial prediction uncertainties. To improve the prediction performance, we also tested the inclusion of oblique geographic coordinates (OGCs) as covariates that reflect spatial position. The following results were achieved: (i) the predictive models demonstrated poor performance using only UAV images as predictors; (ii) the incorporation of OGCs slightly improved the predictions, whereas their uncertainties remained high. We conclude that the inability to accurately predict soil properties using these predictor variables (UAV and OGC) is likely due to the limited access to soil spectral signatures and the high variability of soil properties within what appears to be a homogeneous site, particularly in relation to soil-forming factors. Our results demonstrated the limitations of UAVs’ application for modeling soil properties on a site with homogeneous vegetation, whereas including spatial autocorrelation information can benefit and should be not ignored in further studies. Full article

The pylon has been identified as a highly promising method for enhancing mixing efficiency in scramjet combustors. This work systematically assessed the impact of spanwise, streamwise, and oblique multi-pylon combinations in a supersonic cold flow through numerical simulations, employing pylon-aided ethylene fuel injection under low dynamic pressure conditions. The Reynolds-averaged Navier–Stokes (RANS) equations with the SST k-ω turbulence model are applied during the simulation. Numerical results reveal that, in comparison to the streamwise combination, the spanwise combination exhibits superior flow field characteristics in terms of mixing efficiency, penetration depth, and total pressure loss. For a given injection condition, an optimal distance between pylons exists in the spanwise combination, with the angle between two pylons having minimal influence on mixing efficiency. The oblique multi-pylon combination yields poorer mixing enhancement efficiency and fuel penetration but incurs less total pressure loss in the near field when compared to the spanwise combination. Additionally, the oblique multi-pylon combination demonstrates enhanced mixing efficiency further downstream of the injector than the spanwise combination. This investigation into fuel injection schemes based on multi-pylon combinations offers valuable insights for the structural design of scramjet engines. Full article

Background: Polymerization shrinkage of composite resins affects the marginal closure of direct dental restorations. It is responsible for developing secondary caries and indirectly affects the survival rate of restorations. This study aims to investigate the null hypothesis, which states that there are no significant differences in the marginal microleakage of Class II restorations when examined in vitro using different dental adhesives, whether the restoration material used is a composite with glass fiber reinforcement or not. Methods: Class II cavities were prepared on both proximal surfaces of thirty-six extracted human molars. A single-component (Universal VivaPen) and a two-component (Futurabond DC) self-etch adhesive system were used for the restorations in the control group (Charisma Classic) and the experimental group (Charisma Classic with Interlig glass fiber strip). An oblique layering technique and a 40-s soft-start light-curing polymerization were used. After selective pre-isolation, the specimens were placed in a 0.2% methylene blue solution and incubated at 37 °C for 24 h. The teeth were sectioned in the mesiodistal direction, and two examiners examined and graded the extent of dye penetration. Statistical analysis was conducted using the Mann–Whitney U and chi-square tests (p < 0.05). Results: All the composite restorations reinforced with glass fiber showed significantly reduced dye infiltration compared to the control group (p < 0.05). A significant difference (p < 0.05) was also observed between the two adhesives. Conclusions: The null hypothesis was rejected. Glass fiber strips significantly reduced composite restoration microleakage regardless of the adhesive. The marginal fit of the restoration was also influenced by the adhesive system used. Full article

At present, the typical targets in the air are mainly high-speed impact bodies such as fragments, which pose a great threat to aviation equipment such as drones. It is urgent to study the impact resistance of different initial conditions of fragments to honeycomb sandwich structures. The fragment impact experiment analyzes the fragment flight attitude, fragment power, failure mode, and impact resistance of the structure by changing the different impact velocities on the target plate. In order to study the damage mode and anti-damage performance of several composite honeycomb sandwich structures under oblique penetration impact mode, a total of six groups of composite honeycomb structures were tested by fragment impact sandwich structure at different angles, and the damage law of composite honeycomb sandwich structure in the experiment was compared and analyzed. According to the experimental results, the accuracy of the theoretical model and numerical simulation was verified by fragment impact composite honeycomb sandwich structure. The analysis results show that the failure mode of the composite honeycomb sandwich structure under oblique impact is quite different from that of the traditional structure, which is mainly reflected in the material accumulation type of the failure part. Compared with the traditional structure, the composite honeycomb sandwich structure exhibits better energy absorption efficiency, which is increased by 130% and 600%, respectively. This paper shows the different failure modes of honeycomb sandwich structure under oblique impact and positive impact. The existence of an inclined angle changes the failure mode, increases the damage range, and increases the total energy absorption. It is necessary to further study the failure mechanism of fragment flight angle on honeycomb sandwich structure and provide a reference for the impact resistance design of the structure. Full article

This review focuses on the development and advancements in angular-selective smart windows, with particular emphasis on static windows utilizing guest–host liquid crystal (GHLC) systems. Angular-selective windows are designed to adjust their transmittance based on the angle of incident light, offering enhanced energy efficiency and visual comfort in both architectural and automotive applications. By leveraging the anisotropic absorption properties of dichroic dyes, GHLC-based windows can selectively block oblique sunlight while preserving clear visibility from normal viewing angles. Various liquid crystal (LC) alignment configurations, including vertically aligned, homogeneously aligned, hybrid aligned, uniformly lying helix, and twisted aligned LC cells, have been investigated to optimize light control for different installation angles, such as for automotive windshields and building windows. These advancements have demonstrated significant improvements in energy conservation and occupant comfort by reducing cooling demands and regulating sunlight penetration. This review summarizes key findings from recent studies, addresses the limitations of current technologies, and outlines potential future directions for further advancements in smart window technology. Full article

Background: This report aims to supplement the existing knowledge on the inferior oblique muscle. In particular, this study presents detailed anatomical and histological data concerning the muscle’s entry point (or entry zone) of the nerve to the inferior oblique muscle. Particular attention was paid to the topographical relationships of the nerve to the inferior oblique muscle (NTIO), including the location of its entry point to the muscle’s belly and its anatomical variations. Methods: Sixty orbits from cadaveric hemi-heads fixed in 10% formalin were studied. The course of the NTIO was traced along the lateral border of the inferior rectus muscle as far as its entry point to the inferior oblique muscle. Particular attention was paid to the various ways in which the NTIO’s muscular sub-branches penetrated between the fibers of the inferior oblique muscle. Results: Three types of NTIO entries to the inferior oblique muscle’s belly were distinguished. In the most common type (48.3%), the nerve entered the muscle’s inferior (orbital) surface. In the next most common type (36.7%), terminal muscular sub-branches of the NTIO joined the superior (also referred to as ocular or global) surface of the inferior oblique muscle. In the remaining four cases (15%), the terminal sub-branches of the NTIO were divided into two main groups (superior and inferior) that joined both the superior and inferior surfaces of the muscle. Histological examination confirmed that the distal part of the NTIO shows a characteristic arcuate course (angulation) just before reaching the muscle’s belly. The process for splitting and forming separate muscular sub-branches of the NTIO was observed for all the examined histological specimens at the level of the nerve’s angulation. Conclusions: The presented findings enhance the understanding of the anatomical variations and precise distribution of motor sub-branches reaching the inferior oblique muscle, which may deepen anatomical knowledge and potentially enhance the management of ocular motor disorders. Full article

The aim of this study is to evaluate the safety and efficacy of the use of the IMACTIS^® CT-Navigation™-electromagnetic navigation system (EMNS) in cryoablation CT-guided procedures under local anesthesia for the treatment of upper kidney pole and adrenal lesions. We conducted a retrospective analysis of patients with upper kidney pole lesions and adrenal metastases who underwent cryoablation using the IMACTIS-CT^®-EMNS between January 2019 and April 2023. The EMNS was used to guide the placement of the cryoprobes with CT guidance under local anesthesia. The primary outcome was technical success, defined as the successful placement of the cryoprobes in the target lesion. A total of 31 patients were studied, of whom, 25 patients were treated with cryoablation for upper pole kidney masses, and 6 patients underwent the cryoablation of adrenal metastases during the study period. The mean age was 60 years (range, 36–82 years), and 21 patients were male. All the upper kidney pole lesions were renal cell carcinomas, and regarding adrenal metastases, the primary cancer sites were the lungs (n = 3), breast (n = 2), and the colon (n = 1). The median size of the lesions was 3,8 cm (range, 1.5–5 cm). All procedures were technically successful, with the cryoprobes accurately placed in the target lesions under CT guidance using the EMNS, avoiding the penetration of any other organs using an oblique trajectory. No major complications were reported, and local tumor control was achieved in all cases. Our initial experience using the EMNS for cryoprobe placement during CT-guided interventional procedures under local anesthesia for the cryoablation treatment of upper pole kidney lesions and adrenal metastases showed that it is safe and effective. Full article

The trencher design of the pre-cut transverse sugarcane planter is the basis for realizing deep planting and shallow burial. Aimed at the problems of insufficient seeding space provided by furrows and high resistance to trenching, a structural configuration of a combined trencher suitable for transverse cane planting agronomy was proposed to improve the stability, simplicity, and efficiency of trenching. The collaborative operations of components such as the soil lifting of the leak-proof plow, the soil fragmentation and throwing of the double-disc rotary tiller, the rebound of the fender, the lateral diversion of the furrowing plow, and the motion control of the double rocker arms were comprehensively utilized. The trenching principle of using double-sided guards to block soil backfilling to form a seeding space was applied, as well as pre-side diversion to reduce the forward resistance of plow surfaces. The simulation of the trenching process showed that the combined trencher was available in terms of soil particle transfer and dynamic space-forming capabilities, and the stress distribution of the advancing plow surface was analyzed. Moreover, based on the minimum resistance characteristics, the optimal spacing between the rotary tiller and the furrowing plow and the blade arrangement mode were configured, and the structural parameters of the furrowing plow were optimized to include a soil penetration angle of 20°, an oblique cutting angle of 75°, and a curvature radius of 280 mm. Field experiments have proven that the soil entry movement trajectory, the length and width of the accessible seed placement space, and the average planting depth of cane seeds could all achieve respective design anticipations of the combined trencher. The measured trenching resistance was 7609.7 N, with an error of 22.2% from the predicted value under the same configuration. Full article

Affected by geological factors, the scale of surface deformation in a hilly semi-desertification mining area varies. Meanwhile, there is certain dense vegetation on the ground, so it is difficult to construct a high-precision and complete image of a subsidence basin by using a single monitoring method, and hence the laws of the deformation and inversion of mining parameters cannot be known. Therefore, we firstly propose conducting collaborative monitoring by using InSAR (Interferometric Synthetic Aperture Radar), UAV (unmanned aerial vehicle), and 3DTLS (three-dimensional terrestrial laser scanning). The time-series complete surface subsidence basin is constructed by fusing heterogeneous data. In this paper, SBAS-InSAR (Small Baseline Subset) technology, which has the characteristics of reducing the time and space discorrelation, is used to obtain the small-scale deformation of the subsidence basin, oblique photogrammetry and 3D-TLS with strong penetrating power are used to obtain the anomaly and large-scale deformation, and the local polynomial interpolation based on the weight of heterogeneous data is used to construct a complete and high-precision subsidence basin. Compared with GNSS (Global Navigation Satellite System) monitoring data, the mean square errors of 1.442 m, 0.090 m, 0.072 m are obtained. The root mean square error of the high-precision image of the subsidence basin data is 0.040 m, accounting for 1.4% of the maximum subsidence value. The high-precision image of complete subsidence basin data can provide reliable support for the study of surface subsidence law and mining parameter inversion. Full article

Polarization imaging is a label-free and non-invasive technique that is sensitive to microstructure and suitable for probing the microstructure of living tissues. However, obtaining deep-layer information from tissues has been a challenge for optical techniques. In this work, we used tissue optical clearing (TOC) to increase optical penetration depth and characterize the layered structures of tissue samples. Different tissue phantoms were constructed to examine changes in the polarization features of the layered structure during the TOC process. We found that depolarization and anisotropy parameters were able to distinguish between single-layer and double-layer phantoms, reflecting microstructural information from each layer. We observed changes in polarization parameter images during the TOC process and, by analyzing different regions of the images, explained the sensitivity of these parameters to double-layer structures and analyzed the influence of oblique incident illumination. Finally, we conducted TOC experiments on living skin samples, leveraging the experience gained from phantom experiments to identify the double-layer structure of the skin and extract features related to layered structures. The results show that the combination of backscattering polarization imaging and tissue optical clearing provides a powerful tool for the characterization of layered samples. Full article

To study the perforation performance of CFRP laminates for rail vehicles under high-velocity impact from foreign objects, impact tests on CFRP laminates at a velocity of 163 m/s were carried out, and a corresponding finite element model was established using ABAQUS and verified. The user-defined material subroutine combined the material strain rate hardening effect and the 3D-Hashin damage criterion. The effects of impact velocity, impact object shape, and oblique angle on the perforation performance of CFRP laminates are discussed. Results show that impact velocity positively correlates with impact peak force and residual velocity. Laminates can be perforated by projectiles with a velocity above 120 m/s, and impact velocity greatly influences delamination below 140 m/s. Three shapes of projectile impacting laminates are considered: spherical, cylindrical, and conical. The conical projectile penetrates the laminate most easily, with the largest delamination area. The cylindrical projectile with a flat end suffers the most resistance, and the delaminated area is between the impact conditions of the conical and spherical projectiles. Increasing the angle of inclination increases the impacted area of the laminate and the extent of damage, thus dissipating more energy. The projectile fails to penetrate the laminate when the oblique angle reaches 60°. CFRP composite structures penetrated by high-speed impacts pose a significant threat to the safety of train operations, providing an opportunity for the application of bio-inspired composite structures. Full article

In precision farming technology, the moisture of the soil, its granulometric composition, specific conductivity and a number of other physical and chemical parameters are determined using remote radar sensing. The most important parameters are those measured in the area of the plant root system located well below the “air-surface” boundary. In order to create conditions for the penetration of electromagnetic waves through the “air-surface” interface with a minimum reflection coefficient, the irradiation of the Earth’s surface is carried out obliquely with an angle of incidence close to the Brewster angle. The reflection coefficient, and, consequently, the Brewster angle, depend on the complex dielectric permittivity of the surface soil layer and are not known a priori. To determine the Brewster angle, the usual method is to search for the minimum amplitude of the vertically polarized signal reflected from the surface. Another approach is when the first derivative of the dependence of the modulus of the complex amplitude of a vertically polarized interference wave, taken with respect to the angle of incidence, is set equal to zero. In turn, in real dielectrics such as agricultural soils, the amplitude of the vertically polarized signal reflected from the surface is directly proportional to the reflection coefficient and does not have a pronounced minimum, which reduces the accuracy of the measurements. Based on the solution of the Helmholtz wave equation for a three-layered structure of the propagation medium (air, upper fertile soil layer, soil layer below the groundwater level), a model of the process of forming an interference wave under oblique irradiation of a planar layered dielectric with losses has been developed. Using the developed model, factors influencing the accuracy of determining the Brewster angle have been identified. For the first time, it is proposed to use the phase shift between the oscillations of the interference waves with vertical and horizontal polarization to measure the Brewster angle. A comparative assessment of the accuracy of determining the Brewster angle using known amplitude methods and the proposed phase method has been carried out. The adequacy of the method was experimentally confirmed. Recommendations have been developed for the practical application of the phase method of finding the Brewster angle for assessing the dielectric permittivity of soil and its moisture content. Full article

In this study, we enhance the angular-selective light absorption capabilities of guest–host liquid crystal (GHLC) cells by introducing a novel design featuring a uniform lying helix (ULH) structure. Previously GHLC cells, predominantly vertically aligned cells absorbed obliquely incident light but compromised x-direction visibility. In stark contrast, our ULH-based design allows incident light to seamlessly traverse transmittance in both z- and x-directions while efficiently obstructing oblique incident light in the y-direction. Our innovative ULH-based GHLC cell achieves an impressive optical performance. Specifically, it attains a substantial transmittance rate of 56.7% in the z-direction. Furthermore, in oblique views encompassing both the x- and y-directions, it maintains competitive transmittance rates of 44.2% and 29.5%, respectively. This strategic design not only ensures clear and unobstructed views for building occupants in the z- and x-directions but also contributes significantly to energy conservation by preventing oblique incident light from penetrating, thus reducing cooling requirements. Our ULH-based GHLC cell represents a breakthrough in smart window technology, offering an elegant solution to the challenge of balancing energy efficiency and occupant comfort in architectural settings. This advancement holds promising implications for sustainable building designs by enhancing indoor environmental quality while mitigating energy consumption for cooling, ultimately redefining the potential of smart windows in contemporary architecture. Full article