Search Results (259)

Patient-specific implants (PSIs) in orthognathic surgery offer optimal intraoperative accuracy. However, evidence regarding their postoperative skeletal stability, specifically comparing distinct fixation designs and segmentation patterns, remains limited. We present a retrospective cohort study that evaluated 64 adult patients undergoing customized maxillary orthognathic surgery between January 2020 and June 2025. The primary predictor variables were fixation design (conventional customized plates vs. minimally invasive plates) and maxillary segmentation (monoblock vs. multisegmental). The outcome variable was 3D skeletal stability, measured as linear displacement between preoperative planning and 6-month postoperative imaging. Non-parametric tests compared displacements and clinical instability rates (defined as ≥2.0 mm). Mann–Whitney tests compared landmark displacements, Fisher’s exact tests compared proportions with ≥2.0 mm displacement, and ORs with 95% CIs were computed (α = 0.05). Analysis of 64 patients revealed that median displacement across landmarks ranged from 0.7 to 4.28 mm and 28.1% exhibited displacement ≥ 2.0 mm, primarily in molar and canine regions. While overall instability rates did not differ significantly between single-segment and multisegmental osteotomies (p = 0.28), multisegmental cases showed significantly higher displacement at the left canine (p = 0.027). Plate design was not associated with skeletal instability (p = 0.88), suggesting that minimally invasive plates provide comparable stability to conventional designs. Customized maxillary plates provide reliable postoperative stability with median displacements within clinically acceptable limits (<2 mm). Minimally invasive PSI designs offer stability comparable to conventional extended designs. However, localized instability in multisegmental cases suggests a need for careful biomechanical management regardless of the fixation method used. Full article

Chronic wounds represent a major complication of underlying conditions such as diabetes mellitus, arterial ischemia, surgical wound and burns. This study aimed at the phenotypic and molecular characterization of antimicrobial resistance for a selection of bacterial isolates, originating from wounds harvested from patients hospitalized in the Vascular Surgery and Plastic Surgery wards. The microbiological diagnosis of wound infections was established according to the laboratory’s working protocol. PCR screening of antibiotic resistance genes was performed using a real-time PCR, while the microtiter plate assay was used to determine the biofilm-forming capacity. Testing of biofilm susceptibility to meropenem and amikacin was performed on Calgary biofilm device. Of the 88 bacterial isolates studied, 78.40% were Gram-negative bacilli (GNB)—Klebsiella pneumoniae (K.P), Pseudomonas aeruginosa (P.A), Proteus mirabilis (P.M), Acinetobacter baumannii (A.B), while the remaining 21.60% were Gram-positive cocci (GPC)—Staphylococcus aureus (S.A). All A.B isolates and 92.59% of K.P were carriers of β-lactamase- and carbapenemase-encoding genes, while 57.89% of S. aureus isolates were carriers of mecA (methicillin-resistant). Strong biofilm-forming isolates (B+++) were more frequent in P.A than in K.P (p = 0.002) and P.M (p = 0.02), with a frequency comparable to that of A.B strains (p = 0.212). When analyzing the biofilm reaction to meropenem, a significantly lower susceptibility was detected in the biofilm for K.P isolates, compared to the planktonic ones. Most GNB have been extensively multidrug-resistant, particularly K.P and A.B. Isolates from chronic wounds are major biofilm-formers. A strong and statistically significant association has been identified in the case of K.P and P.M between the presence of resistance genes and the biofilm-forming capacity. These findings highlight the need for a customized therapeutic approach for each chronic wound, considering the mechanisms underlying treatment resistance. These include bacterial virulence factors and the wound microenvironment colonized by the biofilm and the relative contribution of each to the overall resistance profile. Full article

Hypernasality is a common characteristic of several speech disorders and can significantly affect perceived speech intelligibility and quality. Nasometry quantifies nasalance by calculating the proportion of acoustic energy emitted from the nasal cavity relative to the combined nasal and oral acoustic output during speech production and is commonly used in clinical assessment and research. However, commercially available nasometers are costly and limited in portability, restricting their use in resource-limited or remote settings. The primary purpose of this study was to design and build a low-cost, open-source mobile nasometer prototype (“mNasometer”) by leveraging advances in 3D printing, off-the-shelf electronic components, and a custom open-source mobile application. A secondary aim was to compare the electroacoustic and subjective performance of mNasometer with that of a gold-standard commercial nasometer. Electroacoustic analyses focused on comparing long-term averaged spectra and the oral/nasal acoustic isolation between the gold-standard commercial nasometer and the proposed mNasometer, which incorporates a 3D-printed nasal separation plate. In addition, nasalance scores were collected from ten healthy young adult participants using both systems during structured speech production tasks (i.e., reading standard passages or nasal sentences). Agreement between devices was evaluated using correlational analyses and comparative statistical procedures. Long-term averaged spectra exhibited similar profiles between the commercial nasometer and the mNasometer across different test stimuli, indicating comparable capture of stimulus energy distributions. Although the mNasometer demonstrated reduced oral–nasal acoustic isolation relative to the commercial system, objective nasalance scores followed similar overall trends between devices, with statistically significant stimulus-dependent differences observed. Frame-wise correlational analyses revealed significant correlations between nasalance measures obtained from the commercial nasometer and the mNasometer across most of the speech production tasks, suggesting that the reduced isolation did not critically compromise measurement correspondence. In summary, the low-cost, open-source mNasometer prototype provides nasalance measurements that show promising agreement with those of a gold-standard commercial device. Its reduced cost and increased portability suggest potential for expanded research and field-based applications in the objective assessment of nasalance. Full article

Background: Tile C1.2 pelvic ring injuries are characterized by combined rotational and vertical instability and require reliable posterior stabilization. The aim of this exploratory biomechanical study was to compare the construct-level mechanical behavior of three posterior pelvic ring fixation strategies in a standardized Tile C1.2 injury model while maintaining identical anterior symphyseal fixation in all specimens. Methods: Nine fourth-generation composite pelvic specimens with a simulated Tile C1.2 injury pattern were allocated to three groups (n = 3 per group) according to posterior fixation method: anterior sacroiliac plating, sacroiliac screw fixation, and ilioiliac plate fixation. All specimens received the same anterior symphyseal plate. Mechanical testing was performed under monotonic axial compression using a universal testing machine and a custom acetabular support designed to ensure reproducible load transmission. A preload of 50 N was applied before data acquisition, after which displacement was zeroed. Loading was then continued up to a predefined maximum load of 1.9 kN. Axial displacement was obtained from actuator travel, and apparent axial secant stiffness was evaluated at predefined load levels. Results: Across the tested loading range, sacroiliac screw fixation demonstrated the lowest axial displacement and the highest apparent axial secant stiffness, whereas ilioiliac plate fixation showed the greatest displacement and the lowest stiffness values. Anterior sacroiliac plate fixation showed intermediate mechanical behavior. No structural failure occurred within the tested load range. Conclusions: Within the limits of this small synthetic biomechanical study, the investigated posterior fixation strategies showed different construct-level displacement and stiffness profiles under monotonic axial compression when anterior fixation was kept constant. Among the tested posterior constructs, sacroiliac screw fixation was associated with lower displacement and higher apparent stiffness within this experimental model. Full article

Background: Electrochemotherapy enhances the intracellular delivery of anticancer agents through electroporation but is traditionally limited to cytotoxic drugs associated with significant side effects. Vitamin C (ascorbic acid) exhibits selective anticancer activity when accumulated at high intracellular concentrations; however, its therapeutic application is restricted by poor membrane permeability and rapid systemic clearance. Methods: In this study, we investigated whether reversible electroporation, applied using a custom-designed variable plate electrode system designed to deliver a uniform electric field, could potentiate the antitumor efficacy of low-dose vitamin C. Numerical simulations were performed to optimize electrode spacing and stimulation voltage, suggesting homogeneous electric field coverage throughout the tumor volume. The proposed approach was evaluated in vitro using MDA-MB-231 and 4T1 breast cancer cell lines and in vivo in a 4T1 murine breast cancer model. Results: Low-dose vitamin C alone produced minimal cytotoxic effects, whereas its combination with electroporation significantly reduced cell viability and increased apoptotic and necrotic cell death in vitro. In vivo, vitamin C–assisted electrochemotherapy resulted in pronounced tumor growth suppression, with tumor volumes reduced to approximately 0.34-fold of baseline by day 15, accompanied by decreased proliferation and marked tissue disruption. Conclusions: These findings demonstrate that uniform-field reversible electroporation markedly enhances the intracellular delivery and antitumor activity of low-dose vitamin C, supporting this technology-driven strategy as a promising, low-toxicity alternative to conventional chemotherapeutic agents in electrochemotherapy for solid tumors. Full article

Accurate reciprocating tribological testing depends on the mechanical design, kinematic stability, and load application strategy of the testing apparatus. This paper presents the design, construction, and validation of a custom-built linear reciprocating tribometer developed for controlled laboratory testing. The tribometer provides a programmable stroke of up to 500 mm and a sliding-velocity range of 0.1–50 mm/s. The tribometer was validated through finite element analysis, repeated friction tests, and noise measurements. FEM results showed a maximum displacement of 0.1664 mm and a maximum von Mises stress of 7.47 MPa for the moving plate assembly under a 100 N load, while the loading portal exhibited a maximum localized displacement of 0.017 mm and a maximum stress of approximately 13 MPa under combined loading. These conditions correspond to the maximum design load of the developed tribometer. Repeated tests at 10, 15, and 20 mm/s yielded coefficients of variation of 2.84%, 5.90%, and 14.62%, respectively. Acoustic measurements showed standard deviation values in the range 1.868–3.119 dB. The obtained results confirm stable operation, limited structural deformation, and satisfactory repeatability within the analyzed operating range, indicating that the developed tribometer is suitable for controlled reciprocating tribological experiments under representative laboratory conditions. Full article

Background/Objectives: Unilateral condylar hyperplasia is an idiopathic condition that causes facial asymmetry and occlusal problems. Currently, traditional treatment protocol is the combination of orthognathic and extra-oral condylectomy surgery via pre-auricular incision, which can create aesthetic problems with additional risks of facial nerve damage. The purpose of this study was to report management of condylar hyperplasia patients through minimally invasive condylectomy that was planned via virtual methods. Methods: The custom-made cutting guides were produced, and unilateral condylectomy operations were performed via intra-oral approach. Orthognathic surgery with/without genioplasty operations were either done with condylectomy in one session or in an additional session. Results: Custom-made cutting guides produced by virtual methods provided easy operations without any need for additional extra-oral incisions. Planned osteotomies were transferred successfully from the virtual surgical plan and resections of the excess bone tissues were performed using novel piezo surgery devices. The bones were fixed to their pre-planned position using 3D-printed titanium plates. The patients healed without any complications. Results of this innovative virtually guided protocol tested showed functional and esthetic results without any extra-oral scars with no facial nerve damage. Conclusions: Combination of intra-oral condylectomy with orthognathic surgery using 3D-printed titanium cutting guides seems to be an advantageous approach with successful results in terms of aesthetics and function for management of mandibular condylar hyperplasia patients; however, there is an urgent need in the scientific literature for further clinical research with a larger number of subjects. Full article

Driven by the requirements of lightweight design and efficient impact protection, biomimetic hexagonal honeycomb structures have been widely used for energy absorption. However, their dynamic response and energy absorption behavior in underwater environments remain insufficiently understood. To address this gap, this study investigates the impact response and deformation mechanisms of aluminum honeycomb structures under fully submerged conditions relevant to marine engineering. We fabricated honeycomb cores from 5052-H18 aluminum alloy and developed a custom fixture for fluid–structure interaction tests under underwater drop hammer impact conditions. Using force sensors and high-speed photography, we characterized the dynamic impact behavior through load–time and velocity–time responses. Results demonstrate that drainage holes in the support plate serve a dual function: they enable the structure to maintain stable deformation and absorb energy underwater while also significantly enhancing energy absorption capacity. Specifically, the mean crushing force increases by 156.5%, and the energy absorption capacity increases by 333% compared to performance in air. This enhancement arises from the plastic deformation of cell walls and the additional energy dissipation induced by fluid–structure interaction. Overall, this study clarifies the dynamic compression behavior of aluminum honeycombs in underwater environments and demonstrates their potential for marine energy-absorption applications. Full article

In this study, a three-dimensional simulation of a walking-beam reheating furnace was developed to improve the steel slab reheating process and reduce surface oxidation kinetics using computational fluid dynamics (CFD). Combustion, heat transfer, fluid dynamics, and chemical reaction models were integrated into the numerical framework of this study. In addition, dynamic mesh remeshing was coupled through user-defined functions (UDFs), enabling the simultaneous simulation of slab movement and evolution of the involved transport phenomena. Turbulence was modeled with the realizable k-ε formulation, combustion with the Eddy Dissipation model, and radiation with the P-1 model coupled with WSGGM to include CO₂ and H₂O gas radiation. Scale formation was modeled using customized functions based on Arrhenius-type kinetics and Wagner’s oxidation model, evaluating its growth as a function of time, temperature, and furnace atmosphere. The predicted thermal evolution inside the furnace was validated using industrial data, yielding an average deviation of 5%. Furthermore, the proposed operating conditions led to an average slab temperature of 1289.77 °C at the exit of the homogenization zone, which was 16 °C higher than that under the current operation but still within the target range (1250 ± 50 °C). The reduction in combustion air decreased energy losses and improved product quality, lowering the molar oxygen content in the furnace atmosphere from 4.9 × 10² mol to 6.7 × 10¹ mol. Additionally, annual savings of 4,793,472 kg of natural gas and 13,884 tons of steel were estimated owing to reduced oxidation losses. The proposed air–fuel adjustment led to estimated annual energy savings (equivalent to 4,793,472 kg of natural gas) and a reduction in material loss due to oxidation from 4.5% to 3.75% (an absolute reduction of 0.75 percentage points; relative reduction ≈ 16.7%), which has a significant industrial impact on metal conservation and descaling cost reduction. Although there are CFD studies on plate overheating and scale growth separately, this work presents three main contributions: (1) the integration, within a single numerical framework, of combustion, radiation, species transport, oxidation kinetics, and actual plate movement using a dynamic mesh; (2) validation against continuous industrial records (16 thermocouples) and quantification of operational benefits such as fuel savings and reduced material loss; and (3) a comparative analysis between actual and optimized conditions, which standardize the air–methane ratio. Full article

Biodegradable zinc (Zn) has attracted increasing interest as a material for temporary implants, primarily due to its moderate degradation kinetics. In recent years, additive manufacturing of Zn alloys using the laser powder bed fusion method (L-PBF) has shown promising results. Compared to as-cast Zn alloys, it offers preferable customized solutions for patient-specific temporary biomedical implants. Due to the novelty of these printed degradable biomaterials and due to reported cytotoxic effects of Zn alloys, this study investigates additively manufactured ZnAgCu, ZnAgCuMn, and ZnAgCuTi alloys, both in as-printed and post-processed conditions, with a focus on L929 and SAOS-2 biocompatibility. In this work, we demonstrate that the increased porosity and therefore larger surface areas compared to polished Zn-alloy samples affect their biocompatibility. Minimal to no cell proliferation was observed on and near the Zn-alloy test plates after 24 h. Undiluted extracts from as-cast Zn and L-PBF-manufactured plates were initially cytotoxic to SAOS-2 cells. However, as passivation proceeded, cytocompatibility was significantly increased from day 3 onward. Zn²⁺ ion release peaked at 24 h and declined significantly from day 2 to day 10. Compared to the other Zn alloys, ZnAgCuMn exhibited the lowest cytocompatibility. Most intriguingly, 3-month surfaces exhibited reduced cytocompatibility to osteoblasts compared to freshly polished samples. The observed in vitro cytotoxicity motivates further investigation of as-printed and post-processed L-PBF-manufactured Zn alloys, aiming to develop novel surface modification strategies to mitigate the initial ion burst responsible for reduced cytocompatibility and to adjust and tailor the overall degradation kinetics to physiologically tolerable levels tailored to the intended clinical application. Full article

Three-dimensional (3D) culture systems that recapitulate the tumor microenvironment are essential for studying cancer cell behavior, drug response, and cell–matrix interactions. Here, we present a detailed protocol for generating 3D spheroid cultures from murine breast cancer cells using methacrylated gelatin (GelMA)-based bioink and a CELLINK BioX bioprinter. This method enables precise deposition of spheroid-laden GelMA droplets into low-attachment plates, facilitating high-throughput and reproducible 3D culture formation. The protocol includes steps for spheroid formation, GelMA preparation, bioprinting, and post-printing analysis using a customized CellProfiler pipeline. The analysis pipeline takes advantage of the functionality of CellProfiler and ImageJ software (version 2.14.0) packages to create a versatile and accessible analysis tool. This approach provides a robust and adaptable platform for in vitro cancer research, including studies of metastasis, drug resistance, cancer cell lipid metabolism, and TME-associated hypoxia. Full article

Microbiological analysis is crucial for identifying species, assessing infections, and diagnosing infectious diseases, thereby supporting both research studies and medical diagnosis. In response to these needs, accurate and efficient identification of bacterial colonies is essential. Conventionally, this process is performed through manual counting and visual inspection of colonies on agar plates. However, this approach is prone to several limitations arising from human error and external factors such as lighting conditions, surface reflections, and image resolution. To overcome these limitations, an automated bacterial colony counting and classification system was developed by integrating a custom-designed imaging device with advanced deep learning models. The imaging device incorporates controlled illumination, matte-coated surfaces, and a high-resolution camera to minimize reflections and external noise, thereby ensuring consistent and reliable image acquisition. Image-processing algorithms implemented in MATLAB were employed to detect bacterial colonies, remove background artifacts, and generate cropped colony images for subsequent classification. A dataset comprising nine bacterial species was compiled and systematically evaluated using five deep learning architectures: ResNet-18, ResNet-50, Inception V3, GoogLeNet, and the state-of-the-art EfficientNet-B0. Experimental results demonstrated high colony-counting accuracy, with a mean accuracy of 90.79% ± 5.25% compared to manual counting. The coefficient of determination (R² = 0.9083) indicated a strong correlation between automated and manual counting results. For colony classification, EfficientNet-B0 achieved the best performance, with an accuracy of 99.78% and a macro-F1 score of 0.99, demonstrating strong capability in distinguishing morphologically distinct colonies such as Serratia marcescens. Compared with previous studies, this research provides a time-efficient and scalable solution that balances high accuracy with computational efficiency. Overall, the findings highlight the potential of combining optimized imaging systems with modern lightweight deep learning models to advance microbiological diagnostics and improve routine laboratory workflows. Full article

Objectives: The aim of this study was to compare the stiffness-related mechanical response and peak von Mises stress distribution of low-profile 2.4 mm mandibular reconstruction systems (a conventional reconstruction plate, a 3D grid-type plate, and a customized plate) in a virtual atrophic mandible model with a 5 cm segmental defect. Materials and Methods: A CT-based three-dimensional mandible model was created and instrumented with three plate configurations (G1–G3). Linear static finite element analyses were performed under a 300-N masticatory load combined with literature-based muscle force vectors. Peak von Mises stresses were recorded for plates and screws, and the locations of maximum stress concentration were identified. Results: Peak plate stress was highest in the conventional reconstruction plate (G1: 695.5 MPa), followed by the 3D grid-type plate (G2: 595.6 MPa), and lowest in the customized plate (G3: 185.2 MPa). The peak screw stress was 692.9 MPa (G1), 898.0 MPa (G2), and 595.6 MPa (G3). The 3D grid-type plate increased construct stiffness but shifted stress concentration toward the mandibular angle and adjacent screws, whereas the customized plate reduced the peak plate stress and limited the extent of the high-stress region across the defect. Conclusions: Within the limitations of a linear static FEA (stiffness/stress distribution rather than failure load or fatigue resistance), the customized plate (G3) demonstrated the most favorable biomechanical performance (lowest peak plate stress). The 3D grid-type plate (G2) reduced peak plate stress compared with the conventional design (G1) but produced the highest peak screw stress. Practical considerations such as manufacturing lead time and resource requirements may favor off-the-shelf plates; however, a formal cost or operative-time analysis was not performed. Full article

Vertical cavity surface emitting lasers (VCSELs) have shown great potential in high-speed communication, quantum information processing, and 3D sensing due to their excellent beam quality and low power consumption. However, generating high-purity and controllable circularly polarized light usually requires external optical components such as quarter-wave plates, which undoubtedly increases system complexity and volume, hindering chip-level integration. To address this issue, we propose a monolithic integration scheme that directly integrates a custom-designed double-layer asymmetric metasurface onto the upper distributed Bragg reflector of a chiral VCSEL. This metasurface consists of a rotated GaAs elliptical nanocolumn array and an anisotropic grating above it. By precisely controlling the relative orientation between the two, the in-plane symmetry of the structure is effectively broken, introducing a significant optical chirality response at a wavelength of 1550 nm. Numerical simulations show that this structure can achieve a near 100% high reflectivity for the left circularly polarized light (LCP), while suppressing the reflectivity of the right circularly polarized light (RCP) to approximately 33%, thereby obtaining an efficient in-cavity circular polarization selection function. Based on this, the proposed VCSEL can directly emit high-purity RCP without any external polarization control components. This compact circularly polarized laser source provides a key solution for achieving the next generation of highly integrated photonic chips and will have a profound impact on frontier fields such as spin optics, secure communication, and chip-level quantum light sources. Full article

Fatigue crack propagation is a critical failure mechanism in engineering structures, requiring meticulous monitoring for timely maintenance. This research introduces a deep learning framework for estimating fatigue fracture length in metallic plates through acoustic emission (AE) signals. AE waveforms recorded during crack growth are transformed into time-frequency images using the Choi–Williams distribution. First, a clustering system is developed to analyze the distribution of the AE image-based dataset. This system employs a CNN-based model to extract features from the input images. The AE dataset is then divided into three categories according to fatigue lengths using the K-means algorithm. Principal Component Analysis (PCA) is used to reduce the feature vectors to two dimensions for display. The results show how close together the data points are in the clusters. Second, convolutional neural network (CNN) models are trained using the AE dataset to categorize fracture lengths into three separate ranges. Using the pre-trained models ResNet50V2 and VGG16, we compare the performance of a bespoke CNN using transfer learning. It is clear from the data that transfer learning models outperform the custom CNN by a wide margin, with an accuracy of approximately 99% compared to 93%. This research confirms that convolutional neural networks (CNNs), particularly when trained with transfer learning, are highly successful at understanding AE data for data-driven structural health monitoring. Full article