Search Results (39)

Objectives: This retrospective study examines acetabular morphology and defects in children with cerebral palsy (CP). The study discovers the usefulness and reliability of a reconstructed 3D CT measurement technique and compares it to conventional radiographic measurements. Methods: 33 subjects with CP who underwent hip reconstruction, including Dega osteotomy and varus derotation femoral osteotomy, were included and compared to an age-matched group of 42 typically developing children. We reproduced a three directional acetabular index (3DAI), including anterosuperior, superolateral and posterosuperior indices in CT analysis, and compared them with established radiographic measurements for the migration percentage (MP) and the acetabular index (AI). Results: The results showed significantly higher 3DAI in every direction of wall deficiency, accentuating the methods sensitivity for acetabular dysplasia. The interrater and test–retest reliability were robust with ICC = 0.939–0.988 for the CP group. Conventional radiographic measurements demonstrated better discriminative power for identifying hip dislocation and correlated strongly with the 3DAI (p < 0.001). Conclusions: The 3DAI method showcases an important addition to the conventional radiographic measurements by enabling a quantification of the defect amount and direction for operative planning. The study supports the potential of a 3D analysis in the improvement of diagnostic precision and suggests a continuous refinement of the CT measurement technique. Full article

Background/Objectives: The aim of this study was to establish the reliability and accuracy of a new noninvasive tool for FLLA (frontal plane lower limb alignment) assessment: a photometric method. Methods: Sixty-seven subjects (31 males, 36 females, age 11–47 years) participated in the study. Seventeen subjects with orthopedic disorders were marked with radiopaque markers over the anterior superior iliac spines and femoral condyles. One pelvis-to-floor radiograph and one photograph were taken in the same standardized standing position. The hip–knee–ankle (HKA) angle (radiography) and the pelvis–knee–ankle (PKA) angle (photography) were measured by one rater. In 50 healthy participants, anterior superior iliac spines and femoral condyles were marked, and two pelvis-to-floor photographs were taken in a standardized standing position. The PKA angle was measured two times by three raters. The accuracy of the photometric method was tested with Pearson’s correlation coefficient, simple linear regression, and Bland–Altman analysis. The reliability was tested with ICC(2,k) and Bland–Altman analysis. Results: The HKA angle was on average 3.9° more varus than the PKA angle, with a high correlation between measures (r = 0.97, p < 0.0001) and limits of agreement between −1.300 and −6.482. Intrarater (ICC(2,k) > 0.972), interrater (ICC(2,k) = 0.991), and test–retest (ICC(2,k) = 0.980) reliability were excellent. Conclusions: The photometric method is promising as a reliable and accurate noninvasive tool for assessing FLLA. Its accuracy across different study groups has yet to be confirmed in a larger cohort. The advantage of the presented photometric method is the use of the easily palpable anterior superior iliac spine as the proximal femoral axis point. Full article

Composite materials are increasingly in demand. However, challenges such as high raw-material costs and complicated waste management impede their adoption. Overcoming these obstacles requires efficient recycling methods. Pyrolysis effectively recycles carbon fiber-reinforced polymers (CFRPs). This study proposes a cost-effective CFRP recovery approach utilizing conventional ovens to minimize recycling expenses and maximize reclaimed-product value. Pyrolysis was conducted under atmospheric conditions at 450–600 °C, lasting 1–6 h at each temperature. It was optimal at 2.5 h and 500 °C. Higher temperatures caused fiber degradation, and lower temperatures excessively prolonged duration. After determining the optimal conditions, composite plates were produced using recycled carbon fibers and a vacuum-assisted resin infusion process. Subsequent physical characterization and mechanical tests were conducted on these plates to assess the recycled-CFRP properties. The recovered tensile strength and tensile modulus were 88% and 97% that of virgin carbon fibers (vCF), respectively. Full article

Background: S1 nerve roots are difficult to approach during percutaneous procedures for the diagnostic and treatment procedures of low back pain with radicular symptoms. This is harder in older patients with obscure anatomies, due to the low bone density with overimposing degenerative changes in the facets and deformations. The otherwise straightforward procedure for the lumbar nerve roots, placing the needle in the proximity of the S1 under fluoroscopic guidance, becomes quite a challenge. Case presentation: In the proposed technique, the initial target for the needle is the lower part of the S1 facet in the convergent trajectory of the needle. After achieving contact with the bone the tip of the needle is moved caudally as, in proximity, it reaches the dorsal foramina of the S1/S2 segment—this is named “wandering to the hole”. The convergent trajectory of the needle ensures the success of the procedure with a minimal risk of intravenous drug administration, which is characteristic for the suprapedicular technique. Conclusions: The proposed technique is straightforward and reproducible due to the combination of the understanding of the surgical and radiological anatomy of this region, in spite of degenerative changes in the spine. Full article

The prototype of a biomimetic multi-spiked connecting scaffold (MSC-Scaffold) represents an essential innovation in the fixation in subchondral trabecular bone of components for a new generation of entirely cementless hip resurfacing arthroplasty (RA) endoprostheses. In designing such a functional biomaterial scaffold, identifying the microstructural and mechanical properties of the host bone compromised by degenerative disease is crucial for proper post-operative functioning and long-term maintenance of the endoprosthesis components. This study aimed to explore, depending on the occurrence of obesity, changes in the microstructure and mechanical properties of the subchondral trabecular bone in femoral heads of osteoarthritis (OA) patients caused by the MSC-Scaffold embedding. Computed microtomography (micro-CT) scanning of femoral heads from OA patients was conducted before and after the mechanical embedding of the MSC-Scaffold. Bone morphometric parameters such as bone volume/total volume (BV/TV), trabecular thickness (Tb.Th), and trabecular number (Tb.N) for regions surrounding the MSC-Scaffold were computed, and the mechanical properties such as bone density (ρ_B), bone compressive strength (S), and the Young’s modulus (E) within these regions were calculated. A statistically significant increase in BV/TV (by 15.0% and 24.9%) and Tb.Th (by 13.1% and 42.5%) and a decrease in Tb.N (by 15.2% and 23.6%) were observed, which translates to an increase in ρ_B (by 15.0% and 24.9%), S (by 28.8% and 49.5%), and E (by 18.0% and 29.8%) in non-obese patients and obese patients, respectively. These changes in properties are favorable for the mechanical loads’ transfer from the artificial joint surface via the MSC-Scaffold to the periarticular trabecular bone of the OA femoral head in the postoperative period. Full article

This study aimed to investigate the degeneration of the meniscal tissue in osteoarthritic knees and to adapt the Bonar score and its modifications to develop a microscopic examination. This study included consecutive patients who underwent total knee arthroplasty for symptomatic end-stage gonarthrosis. During the surgery, the menisci were completely dissected to preserve their original shapes. The samples were prepared using the hematoxylin and eosin (H&E) staining method and the Alcian blue protocol and were examined under light microscopy. The extent of histopathological changes was assessed based on the classical Bonar score assumptions. Additionally, in the second step of the examination, menisci remnants were evaluated using the modified Bonar score developed by Zabrzyński et al. The study involved 44 patients, from whom 83 samples of knee menisci were obtained. Histological examination of the meniscal specimens under a light microscope revealed tissue degeneration in all cases, in both the medial and lateral menisci. The mean classical Bonar score was 8.3571 and the mean modified Bonar score was 6.9398. There were no statistically significant differences in classical Bonar score assessment between medial and lateral menisci (p = 0.3014). There were no statistically significant differences in the modified-Bonar score assessment between medial and lateral menisci (p = 0.3620). We show that both menisci are implicated in the degenerative process, with high scores in the Bonar system, regardless of knee axial deformity. The Bonar score, along with its modifications, can be readily employed in the microscopic assessment of meniscus pathology. Full article

Many dynamic random-access memory (DRAM) manufacturing companies encounter significant resistance value deviations during the PVD sputtering process for manufacturing Ti thin films. These resistance values are influenced by the thickness of the thin films. Current mitigation strategies focus on adjusting film thickness to reduce resistance deviations, but this approach affects product structure profile and performance. Additionally, varying Ti thin film thicknesses across different product structures increase manufacturing complexity. This study aims to minimize resistance value deviations across multiple film thicknesses with minimal resource utilization. To achieve this goal, we propose the TSDTM-ANN-GA framework, which integrates the two-stage dynamic Taguchi method (TSDTM), artificial neural networks (ANN), and genetic algorithms (GA). The proposed framework requires significantly fewer experimental resources than traditional full factorial design and grid search method, making it suitable for resource-constrained and low-power computing environments. Our TSDTM-ANN-GA framework successfully identified an optimal production condition configuration for five different Ti thin film thicknesses: Degas temperature = 245 °C, Ar flow = 55 sccm, DC power = 5911 W, and DC power ramp rate = 4009 W/s. The results indicate that the deviation between the resistance values and their design values for the five Ti thin film thicknesses decreased by 86.8%, 94.1%, 95.9%, 98.2%, and 98.8%, respectively. The proposed method effectively reduced resistance deviations for the five Ti thin film thicknesses and simplified manufacturing management, allowing the required design values to be achieved under the same manufacturing conditions. This framework can efficiently operate on resource-limited and low-power computers, achieving the goal of real-time dynamic production parameter adjustments and enabling DRAM manufacturing companies to improve product quality promptly. Full article

The purpose of this work was to test a new setup to pump water with entrained air for application in gas fermentation. A mixed flow, where gas is contained in a liquid to be pumped, rapidly reduces the efficiency of a conventional pump, due to the compressibility of the gas. It is not always possible to degas the fluid, for instance in gas fermentation, which is preferably carried out in tubular reactors (loop fermenters) to achieve a high conversion rate of the gaseous feedstocks. Method: In this work, a rim-driven thruster (RDT) was tested in a lab-scale, cold flow model of a loop reactor with 5–30% (by volume) of gas fraction (air) in the liquid (water) as alternative propulsion element (6 m total pipe length, ambient temperature and pressure). As a result, it was found that the RDT, in connection with a guiding vane providing swirling motion to the two-phase fluid, could pump a mixed flow with up to 25.7% of gas content (by volume) at atmospheric pressure and 25 °C and 0.5 to 2 m/s flow speed. In conclusion, an RDT is advantageous over a classic propulsion element like a centrifugal pump or axial flow pump for transporting liquids with entrained gases. This article describes the potential of rim-driven thrusters, as known from marine propulsion, in biotechnology, the chemical industry, and beyond, to handle multiphase flows. Full article

This article introduces an eco-friendly method for the reclamation of carbon fiber-reinforced polymers (CFRP). The research project involved numerous experiments using microwave-assisted pyrolysis (MAP) to explore a range of factors, such as the inert gas flow, the power level, the On/Off frequency of rotation, and the reaction duration. To design the experiments, the three-level Box–Behnken optimization tool was employed. To determine the individual and combined effects of the input parameters on the thermal decomposition of the resin, the data were analyzed using least-squares variance adjustment. The results demonstrate that the models developed in this study were successful in predicting the direct parameters of influence in the microwave-assisted decomposition of CFRPs. An optimal set of operating conditions was found to be the maximum nitrogen flow (2.9 L/min) and the maximum operating experimental power (914 W). In addition, it was observed that the reactor vessel’s On/Off rotation frequency and that increasing the reaction time beyond 6 min had no significant influence on the resin elimination percentage when compared to the two other parameters, i.e., power and carrier gas flow rate. Consequently, the above-mentioned conditions resulted in a maximum resin elimination percentage of 79.6%. Following successful MAP, various post-pyrolysis treatments were employed. These included mechanical abrasion using quartz sand, chemical dissolution, thermal oxidative treatment using a microwave (MW) applicator and thermal oxidative treatment in a conventional furnace. Among these post-treatment techniques, thermal oxidation and chemical dissolution were found to be the most efficient methods, eliminating 100% of the carbon black content on the surface of the recovered carbon fibers. Finally, SEM evaluations and XPS analysis were conducted to compare the surface morphology and elementary constitution of the recovered carbon fibers with virgin carbon fibers. Full article

We analyzed hydrological responses to changing climate and land use/land cover (LULC) for the past (1985–2020) and future (2021–2080) in the Chemoga watershed of the Upper Blue Nile Basin. The watershed comprises four agroecological environments: Moist Kolla, Moist Weyna Dega, Moist Dega, and Wet Wurch. Past and projected LULC changes under business-as-usual (BAU) and land conservation (LC) scenarios were utilized. Climate projections from 2021 to 2080, under two Shared Socioeconomic Pathways (SSP2-4.5 and SSP5-8.5), were downscaled from Global Climate Models. Utilizing the Soil and Water Analysis Tool, we assessed impacts on mean annual surface runoff (SR) and evapotranspiration (ET). Maximum and minimum temperatures increased significantly in the past and future climate scenarios, with a significant rainfall increase observed under SSP5-8.5. Historical trends revealed a 16.6% increase in SR and 7% in ET from 1983–2002 to 2003–2020. Under BAU LULC with the SSP2-4.5 (SSP5-8.5) climate scenario, SR increased by 24% (26.1%) and ET by 3.1% (4.4%) from 2003–2020 to 2021–2050, followed by a subsequent SR rise of 13.7% (14.0%) and ET increase of 6.0% (5.7%) from 2021–2050 to 2051–2080. Conversely, the LC LULC with SSP2-4.5 (SSP5-8.5) resulted in a 5.3% (4.2%) SR decrease and ET increase of 9.7% (11.3%) from 2003–2020 to 2021–2050 and a further SR decrease of 1% (0.7%) and 6.1% (6.9%) ET increase from 2021–2050 to 2051–2080. The Moist Kolla agroecology experienced the highest SR increase due to vegetation clearances for commercial farming. Meanwhile, the LC scenario indicated substantial decreases in SR and marginal increases in ET in the Moist Weyna Dega agroecology due to forest restoration on steep slopes. Overall, SR showed greater sensitivity to LULC changes, while ET was more responsive to climate changes. The results emphasize considering diverse agroecological contexts for effective water resource management under changing climate and LULC scenarios. Full article

Utilizing titanium diboride (TiB₂) inoculation for grain-refining purposes is a widely established practice in aluminum casthouses and foundries. Since this inoculation is usually implemented jointly with or between routine melt treatment steps ahead of casting, it is important to know whether and how other melt treatment processes affect the fade of TiB₂ particles. For the present study, we investigated the influence of degassing process on the separation behavior of TiB₂ particles in aluminum melt. Multiple sampling methods were employed and the samples were analyzed via spectrometer analysis. The removal efficiency of TiB₂ during the gas-purging process of 5083 aluminum melt was confirmed to be significant over 10 min of treatment time. The rate at which the TiB₂ content decays was found to increase with the impeller rotary speed from 400 rounds per minute (rpm) to 700 rpm. The separation rate of TiB₂ particles was obtained to be 0.05–0.08 min⁻¹ by fitting the experimental data. Particle mapping results suggest that the TiB₂ particles were separated to a dross layer. The obtained experimental results were used to quantitatively evaluate the conventional deterministic flotation model. The deviation between the conventional model and the experimental data was explained through the entrainment–entrapment (EE) model. Suggestions were made for future analytical and experimental works which may validate the EE model. Full article

Bio-based plastics made of food-safe compostable materials, such as thermoplastic starch (TPS), can be designed into films that have potential to replace many non-biodegradable single-use plastic (SUP) items. TPS film characteristics, such as elongation at break and tensile strength, are largely affected by the choice of the plasticizers used in formulation. Our work identifies the mechanical properties and the chemical structural differences between TPS films made with two different plasticizer mixtures that have not yet been compared alongside one another: deep eutectic solvent choline chloride/urea (1:2) (CC:U) and glycerol with an acetic acid catalyst (AA:G). Potato-based TPS samples were formed by mixing each plasticizer with a consistent amount of potato starch and distilled water with heat. After gelation formation, the viscous TPS mixture was centrifuged to degas and extruded. Films were dried at controlled room temperature. Characterization included the tensile testing of coupons according to ASTM (American Society of Testing and Materials) standard D638, attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy, X-ray diffraction (XRD), melting point (MP), and scanning electron microscopy (SEM). The AA:G films displayed significantly higher tensile strength (M = 2.04 ± 1.24 MPa) than the CC:U films (M = 0.18 ± 0.08 MPa); however, the CC:U films had higher elongation at break (M = 47.2 ± 3.6%) than the AA:G films (M = 31.1 ± 12.6%). This can be explained by the difference in functional groups, composition, and the degree of crystallinity evidenced by the FTIR, XRD, MP, and SEM results. Our findings suggest that potato-based TPS films with an AA:G plasticizer mixture hold promise for SUP applications that require more strength, while CC:U films may be more suited for wraps and bags that require flexibility. These innovations can aid to mitigate the environmental impact of harmful plastic waste. Full article

Late-discovered developmental hip dysplasia deformities often necessitate complex surgical treatments and meticulous preoperative planning. The selection of osteotomies is contingent upon the patient’s age and the specific structural deformity of the hip. In our anatomical hip model, derived from the data of a 12-year-old patient, we performed virtual osteotomies that are commonly recommended for such cases. We precisely constructed geometric models for various osteotomies, including the Dega, Pemberton, Tönnis, Ganz, Chiari pelvic, and Pauwels femoral osteotomies. We employed Autodesk Inventor for the finite element analysis of the hip joint and the corrective osteotomies. In comparing one-stage osteotomies, we noted that the Dega and Ganz pelvic osteotomies, especially when combined with the Pauwels femoral osteotomy, yielded the most favorable outcomes. These combinations led to enhanced femoral head coverage and reduced intra-articular pressure. Furthermore, we calculated the femoral head-to-acetabulum volume ratio for both the Dega and Pauwels osteotomies. The encouraging results we obtained advocate for the integration of finite element analysis in virtual osteotomies of the pelvis and femur as a preoperative tool in the management of developmental hip dysplasia. Full article

This paper presents advances in designs of resurfacing arthroplasty endoprostheses that occurred through their historical generations. The critical characteristics of contemporary generation hip resurfacing arthroplasty endoprostheses are given and the failures resulting from the specific generation cemented and short stem fixation of the femoral component are reviewed. On the background of these failures, the critical need arises for an alternative approach to the fixation of components of resurfacing arthroplasty leading towards the first generation of biomimetic fixation for resurfacing arthroplasty endoprostheses. The state of the art of the completed bioengineering research on the first biomimetic fixation for resurfacing arthroplasty endoprostheses is presented. This new design type of completely cementless and stemless resurfacing arthroplasty endoprostheses of the hip joint (and other joints), where endoprosthesis components are embedded in the surrounding bone via the prototype biomimetic multi-spiked connecting scaffold (MSC-Scaffold), initiates the first at all generations of biomimetic endoprostheses of diarthrodial joints. Full article

Background: Developmental dysplasia of the hip (DDH) is a common disorder of atypical hip development. Pelvic osteotomy (e.g., according to Salter, Pemberton or Dega) may be indicated for children with DDH at walking age. The most popular postoperative treatment is a hip spica cast. Alternative postoperative options include abduction braces and non-weightbearing protocols combined with physical therapy. The aim of this systematic review was to determine the most effective form of postoperative treatment after unilateral pelvic osteotomy in children with DDH in terms of clinical and radiological outcomes and complications. Methods: A systematic review was conducted and reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis 2020 guidelines and registered in the international prospective register of systematic reviews. Articles were selected from PubMed, Embase and Cochrane databases. The quality of all (non-)randomized included studies was assessed using the Methodological Index for Non-Randomized Studies (MINORS) criteria. Results: The search strategy yielded 3524 articles. Fourteen articles with 367 total hips were included in this review. A total of 312 hips were treated with spica casts, 49 with abduction braces and 6 with non-weightbearing protocols. The quality of evidence was moderate (MINORS, 3–12 points). All types of postoperative treatments had good clinical outcomes overall, without secondary displacement of the osteotomy. Clinical outcomes for spica casts were reported according to McKay’s criteria in 135 hips, with 123 excellent and 12 good results. Clinical outcomes for abduction braces showed satisfaction for all parents (49 of 49). The radiological outcome was overall well preserved with any postoperative treatment. There was a higher complication rate with the use of hip spica casts, including avascular necrosis, pain complaints and superficial infections. Conclusion: This systematic review showed no benefit of postoperative spica casts compared with abduction braces and avoidance of weightbearing after simple pelvic osteotomy for residual DDH. Full article