Search Results (936)

Optical communication is a critical technology for future deep space exploration, offering substantial advantages in transmission capacity and spectrum utilization. This paper establishes a comprehensive theoretical framework for avalanche photodiode (APD)-based deep space optical uplink communication under combined channel impairments, including atmospheric and coronal turbulence induced beam scintillation, pointing errors, angle-of-arrival (AOA) fluctuations, link attenuation, and background noise. A closed-form analytical channel model unifying these effects is derived and validated through Monte Carlo simulations. Webb and Gaussian approximations are employed to characterize APD output statistics, with theoretical symbol error rate (SER) expressions for pulse position modulation (PPM) derived under diverse impairment scenarios. Numerical results demonstrate that the Webb model achieves higher accuracy by capturing APD gain dynamics, while the Gaussian approximation remains viable when APD gain exceeds a channel fading-dependent gain threshold. Key system parameters such as APD gain and field-of-view (FOV) angle are analyzed. The optimal APD gain significantly influences the achievement of optimal SER performance, and angle of FOV design balances AOA fluctuations tolerance against noise suppression. These findings enable hardware optimization under size, weight, power, and cost (SWaP-C) constraints without compromising performance. Our work provides critical guidelines for designing robust APD-based deep space optical uplink communication systems. Full article

Background/Objectives: Early-onset scoliosis (EOS) frequently requires growth-friendly interventions, such as magnetically controlled growing rods (MCGRs), followed by definitive spinal fusion upon skeletal maturity. The optimal implant density (ID) for final posterior spinal fusion in these patients remains controversial. This study aimed to compare the radiographic, surgical, and economic outcomes associated with high-density (HD) versus low-density (LD) screw constructs in EOS patients previously treated with MCGRs undergoing definitive fusion. Methods: This retrospective study included 27 EOS patients who underwent definitive posterior spinal fusion between January 2017 and September 2022. Participants were categorized into two groups: HD (n = 13) and LD (n = 14). Primary outcomes included coronal and sagittal radiographic parameters assessed at early postoperative and final follow-up visits (minimum of 2 years). The secondary outcomes analyzed were major postoperative complications (grade ≥ IIIB according to Clavien–Dindo–Sink Classification [CDSC]), operative time, blood loss, hospital stay length, and total implant costs. Results: Baseline characteristics between the HD and LD groups were comparable. Early postoperative radiographic assessment demonstrated significantly greater thoracic kyphosis (16.3 ± 7.6° vs. 10.9 ± 14.4°, p = 0.021) and T1-S1 spinal height (43.3 ± 6.7 mm vs. 39.1 ± 4.3 mm, p = 0.039) in the HD group. At final follow-up, only T1-S1 spinal height remained significantly higher in the HD group (45.4 ± 7 mm vs. 39.7 ± 5.1 mm, p = 0.021). Implant costs were significantly higher in the HD group (EUR 6046.5 ± 1146.9 vs. EUR 4376.4 ± 999.4, p < 0.001), while operative time, blood loss, and hospital stay length showed no significant differences. HD constructs had three major complications requiring surgical revision, whereas LD constructs reported no perioperative complications but experienced three late-onset complications also necessitating revision surgery. Conclusions: LD constructs provided comparable long-term radiographic and clinical outcomes to HD constructs, with significantly lower implant-related costs. Despite initial superior kyphosis correction in HD constructs, this benefit diminished by the final follow-up. These findings support a selective, lower-density screw placement strategy to minimize costs and surgical complexity without compromising patient outcomes in EOS undergoing definitive spinal fusion. Full article

Objective: This descriptive systematic review aimed to assess in the available literature on the current application and overall performance of Artificial Intelligence (AI) models in the diagnosis and classification of Rotator Cuff Tears (RCTs) using MRIs. Methods: The systematic review was performed by two of the authors from 2020 to November 2024. Only diagnostic studies involving AI application to MRI images of the rotator cuff were considered, including supraspinatus and biceps tears. Studies evaluating AI applications to Ultrasound or X-ray, or including only healthy rotator cuffs, were not analyzed in this paper. Results: The coronal plane in the T2 sequence emerged as the predominant imaging protocol, with the VGG network being the most widely utilized AI model. The studies included in this research exhibited a solid performance of the AI models with accuracy, ranging from 71.0% to 100%. The statistical analysis revealed no significant differences (p > 0.05) in accuracy, sensitivity, specificity, or precision between AI and human experts across studies that included such comparisons. Conclusions: While AI can significantly improve diagnostic efficiency and workflow optimization, future studies must focus on external validation, regulatory approval, and AI-human collaboration models to ensure safe and effective integration into orthopedic imaging. Full article

Background/Objectives: One of the surgical treatments for lumbar foraminal stenosis, full endoscopic foraminotomy, is known for its numerous advantages and favourable clinical outcomes. While previous studies have analyzed preoperative radiological risk factors associated with recurrence within one year after endoscopic foraminal decompression, no research has investigated postoperative radiological changes. The aim of this study is to analyze the radiological changes occurring in cases of early recurrence within six months after endoscopic foraminal decompression. Methods: A retrospective review was conducted on patients with unilateral lumbar foraminal stenosis who underwent full endoscopic foraminotomy at a single institution. The study included 11 recurrent patients who initially experienced symptomatic improvement and sufficient neural decompression on radiological evaluation, but exhibited recurrent radicular pain and radiological restenosis within six months postoperatively. Additionally, 33 control patients with favourable clinical outcomes and no evidence of restenosis were analyzed. Preoperative and postoperative plain X-ray imaging was used to evaluate sagittal and coronal parameters reflecting spinal anatomical characteristics, including disc height, foraminal height, disc wedging, coronal Cobb’s angle, total lumbar lordosis angle, segmental lumbar lordosis angle, and dynamic segmental lumbar lordosis angle. The study aimed to analyze postoperative changes in these parameters between the recurrent and control groups. Clinical outcomes were assessed using the Visual Analog Scale (VAS). Results: There were no significant differences between the groups in terms of age, sex distribution, presence of adjacent segment disease, or existence of Grade 1 spondylolisthesis. Analysis of preoperative and postoperative radiological changes revealed that, in the recurrent group, disc height and foraminal height showed a significant decrease postoperatively, while disc wedging and the coronal Cobb’s angle demonstrated a significant increase. In contrast, the control group exhibited a significant postoperative increase in the total lumbar lordosis angle and segmental lumbar lordosis angle. Conclusions: Progressive worsening of disc wedging and the coronal Cobb’s angle, and reductions in disc and foraminal height, along with minimal improvement in lumbar lordosis following TELF, suggest the presence of irreversible preoperative degenerative changes. Careful radiologic assessment and close postoperative monitoring are essential to identify patients at risk of early recurrence. Full article

Background: The combination of two or more different types of traumatic dental injuries occurring concurrently to the same tooth presents a significant clinical challenge. By focusing on a rare combination of injuries, this case study explores the issues of delayed management of root fractures accompanied by coronal extrusions in immature maxillary permanent central incisors, underscoring the necessity for tailored approaches when guidelines for intervention were unmet. Methods: The case involves an eight-year-old boy who delayed seeking care for approximately a year after suffering trauma to his upper front teeth in a fall accident at school. The clinical examination revealed partial displacement of two maxillary central incisors in an incisal direction, resulting in increased mobility. Radiographs further showed horizontal root fractures in the apical third of both extruded incisors. Encouragingly, the injured teeth exhibited a normal response to electric pulp testing without signs or symptoms of pulpal pathology, suggesting pulp vitality and eliminating the need for root canal treatment. The extruded coronal fragments were repositioned orthodontically using a utility arch. Results: At the 14-month follow-up, the affected incisors were clinically asymptomatic, functionally satisfactory, and esthetically pleasing. Conclusions: Conservative orthodontic management of extrusive luxation concomitant with root fracture in immature permanent teeth may prove effective in select cases, particularly when long-term follow-up and proper oral care are maintained. Full article

The Edinburgh Visual Gait Score (EVGS) is a commonly used clinical scale for assessing gait abnormalities, providing insight into diagnosis and treatment planning. However, its manual implementation is resource-intensive and requires time, expertise, and a controlled environment for video recording and analysis. To address these issues, an automated approach for scoring the EVGS was developed. Unlike past methods dependent on controlled environments or simulated videos, the proposed approach integrates pose estimation with new algorithms to handle operational challenges present in the dataset, such as minor camera movement during sagittal recordings, slight zoom variations in coronal views, and partial visibility (e.g., missing head) in some videos. The system uses OpenPose for pose estimation and new algorithms for automatic gait event detection, stride segmentation, and computation of the 17 EVGS parameters across the sagittal and coronal planes. Evaluation of gait videos of patients with cerebral palsy showed high accuracy for parameters such as hip and knee flexion but a need for improvement in pelvic rotation and hindfoot alignment scoring. This automated EVGS approach can minimize the workload for clinicians through the introduction of automated, rapid gait analysis and enable mobile-based applications for clinical decision-making. Full article

Purpose: The aim of this in vitro study was to investigate the adhesive bond strength of glass fiber posts when cemented with universal resin cement in two different adhesion modes: adhesive and self-adhesive. Methods: A total of 20 extracted single-root teeth were endodontically treated, decoronated and prepared to receive glass fiber posts (GFPs) with a diameter of 1.6 mm (RelyX fiber post 3D). Specimens were randomly divided into two groups: (G1) GFPs were cemented using RelyX Universal cement in self-adhesive mode, and (G2) GFPs were cemented using Scotch Bond Universal Plus and RelyX Universal cement (adhesive mode). Afterwards, the specimens were sliced at three root levels: coronal, middle and apical. Bond strength was measured using a push-out test. Data were analyzed with a two-way analysis of variance (ANOVA) test and independent sample T-test. Results: Bond strength was significantly influenced by the adhesive strategy (p < 0.025) and the position of the root third (p < 0.007). Microscopic analysis of failure mode revealed a higher prevalence of adhesive failures (cement–dentine). Conclusions: Glass fiber posts cemented with universal resin cement applied in adhesive mode showed significantly higher push-out bond strength than when applied in self-adhesive mode. In both study groups, the apical root regions exhibited the highest retention values, followed by the middle and coronal regions. Full article

Background/Objectives: This study aimed to assess and compare the elimination of the smear layer and microhardness of dentin in root canals after sequential versus continuous chelation using different agitation techniques. Methods: Sixty-four palatal roots of upper first molars were instrumented to size X3 (Protaper Next files). According to the irrigant solution, samples were assigned to two groups (N = 32/group), 3% NaOCl irrigation followed by 17% EDTA (sequential chelation (SC)), or dual-rinse (3% NaOCl/9% HEDP) irrigation (continuous chelation (CC)). Each group has been divided into four subgroups (n = 8/subgroup), based on agitation techniques used: conventional needle (CN) (control group), EndoActivator (EA), ultrasonic agitation (UAI), and Er.Cr.YSGG 2780 nm (laser). SEM images assessed the smear layer, and Vicker microhardness (VHN) was performed at 50 and 100 µm depths. Data were analyzed using: Kruskal–Wallis, Wilcoxon, and the Mann–Whitney U test. Statistical significance was set at p < 0.05. Results: In the UAI and laser agitation, CC significantly reduced the smear layer presence compared to SC in the apical and coronal thirds, respectively (p < 0.05), and no significant differences were observed in the CN and EA groups between SC and CC (p > 0.05). There were significantly higher VHNs of dentine in CC groups than in SC groups in all sections and depths, except in the apical of the CN group at 50 µm and the coronal section of EA and UAI groups at 100 µm. Conclusions: CC was comparable to SC in smear layer removal. CC had a less detrimental effect on dentin compared with SC. Full article

Background and Objectives: This retrospective cohort study compared selective thoracic fusion (STF) and non-STF for adolescent idiopathic scoliosis (AIS) Lenke 1B/1C curves. Although STF is considered an attractive option for patients with a compensatory lumbar curve, direct clinical comparisons between STF and non-STF remain limited. Materials and Methods: AIS patients (≥2 years follow-up) undergoing posterior spinal fusion were divided into STF (57 cases) and non-STF (21 cases) groups. The correction rates of their main thoracic (MT) and thoracolumbar/lumbar (TL/L) curves, coronal balance, and SRS-22r scores were statistically compared. Results: Two years after the operation, while MT curve correction and coronal balance showed no significant differences, TL/L curve correction was significantly higher in the non-STF group. In contrast, the STF group had a significantly higher SRS-22r function score, with comparable results for self-image and satisfaction. Conclusions: Both STF and non-STF present distinct characteristics that should be considered to optimize surgical decision-making. Full article

Background/Objectives: Implant placement in cases of severe bone atrophy or compromised alveolar bone requires careful planning, especially in the anterior maxilla. The nasopalatine canal (NPC) and its cortical walls offer potential anchorage sites. This study evaluates the NPC’s anatomical characteristics using cone beam computed tomography (CBCT) to assess its suitability for implant anchorage. Methods: A retrospective analysis of 150 CBCT scans from three dental clinics in Poland was conducted. NPC measurements—including length, width, number of canals, and distances to adjacent anatomical structures—were taken in the sagittal, coronal, and axial planes. Statistical tests included Pearson correlation and Student’s t-test to explore relationships between NPC dimensions and gender. Results: The mean NPC length was 10.27 mm and mean width 3.55 mm. Significant gender differences were observed in the canal length, width, and distances to the labial and palatal plates (p < 0.05). Strong positive correlations were found between the canal width at the palate base and other parameters, such as the midpoint width (r = 0.58) and diameter (r = 0.44). The distance from the palatal opening to the labial plate showed the strongest correlation (r = 0.67), indicating enhanced cortical anchorage potential with increased canal dimensions. Discussion: NPC morphology varied (cylindrical, funnel-like, hourglass), aligning with prior studies. Larger diameters were linked to single-canal configurations. Implant placement strategies—such as direct canal insertion or lateralization—can be effective, especially with polished, single-piece implants that reduce soft tissue ingrowth and improve primary stability. Conclusions: Understanding NPC anatomy is crucial for implant planning in atrophic maxillae. With the proper technique, NPC use for cortical anchorage is a viable treatment option. Full article

Background/Objectives: Despite recent advances in minimally invasive extrapleural lateral approaches, oblique lateral interbody fusion (OLIF) at the upper lumbar level is often difficult and limited to optimal reconstruction. We aimed to compare the radiological outcomes and approach-related complications of OLIF between the upper (L1–2 or L2–3) and lower (L3–4 or L4–5) levels. Methods: This study is a retrospective review of OLIF in the upper (n = 63) and lower (n = 60) lumbar level groups. Radiological parameters included the anterior/posterior disc height, coronal/sagittal disc angle, cage position, cage subsidence, and fusion rate at a postoperative 1-year follow-up. Approach-related complications including pleural/peritoneal lacerations, neurovascular injury, and other organ injuries were examined. Results: The baseline radiological parameters were similar between the two groups (all p > 0.05). At 1-year postoperatively, the anterior disc height (ADH) was significantly greater in the lower-level group (p = 0.031), while no significant differences were observed in the posterior disc height, coronal/sagittal disc angle, cage anterior position, or cage subsidence rate (all p > 0.05). The fusion rates were 97.9% and 95.0% at the upper and lower lumbar levels, respectively (p = 0.146). During OLIF at the upper lumbar level, chest tube insertion due to pleural laceration was observed in 11 (17.5%) cases. One case (1.2%) of segmental artery injury and two cases (3.2%) of pseudo-hernia were attributed to iliohypogastric nerve injury. Conclusions: Although the extrapleural approach in OLIF at the upper lumbar level is often limited, the radiological outcomes were comparable to those of OLIF at the lower lumbar level. Full article

Objectives: The purpose of this study was to assess whether a 3-min 2D knee protocol can meet the needs for clinical application if using a SuperResolution reconstruction approach. Methods: In this prospective study, a total of 20 volunteers underwent imaging of the knee using a 3T MRI scanner (Philips Ingenia Elition X 3.0T, Philips). The imaging protocol, consisting of a fat-saturated 2D proton density sequence in coronal, sagittal, and transverse orientations, as well as a sagittal T1-weighted sequence, was acquired with standard and ultra-low resolution. The standard sequences were reconstructed using an AI-assisted Compressed SENSE method (SmartSpeed). The ultra-low-resolution sequences have been reconstructed using a vendor-provided prototype. Four experienced readers (two radiologists and two orthopedic surgeons) evaluated the sequences for image quality, anatomical structures, and incidental pathologies. The consensus evaluation of two different experienced radiologists specialized in musculoskeletal imaging served as the gold standard. Results: The acquisition time for the entire protocol was 11:01 min for standard resolution and 03:36 min for ultra-low resolution. In the overall assessment, CS-SuperRes-reconstructed sequences showed slightly improved accuracy and increased specificity compared to the standard CS-AI method (0.87 vs. 0.86 and 0.9 vs. 0.87, respectively), while the standard method exhibited a higher sensitivity (0.73 vs. 0.57). Overall, 24 out of 40 pathologies were detected in the ultra-low-resolution images compared to 26 in the standard images. Conclusions: The CS-SuperRes method enables a 2D knee protocol to be completed in 3 min, with improved accuracy compared to the clinical standard. Full article

Background and Objectives: Successful endodontic treatment requires thorough disinfection and removal of the smear layer to prevent reinfection. However, conventional irrigants like sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) can compromise dentin integrity. This study assessed the efficacy of the Synergistic Microbicidal and Ablative Root canal Technique (SMART), which integrates AromaRoot, a biocompatible irrigation solution based on quaternary ammonium compounds, with 980 nm diode laser activation, to enhance bacterial reduction and smear layer removal. Materials and Methods: Sixty extracted single-rooted human teeth were inoculated with Enterococcus faecalis and divided into four treatment groups using NaOCl, AromaRoot, and 980 nm laser, either alone or in combination. Bacterial counts were measured as colony-forming units per milliliter (CFU/mL). For smear layer analysis, 56 extracted teeth were prepared and irrigated using EDTA, AromaRoot, and laser activation, followed by scanning electron microscopy to evaluate dentinal tubule exposure. Data were analyzed using Kruskal–Wallis and ANOVA. Results: The combination of AromaRoot, NaOCl, and laser activation achieved a 99.00% bacterial reduction (from 8082 to 60 CFU/mL, p < 0.001), outperforming NaOCl alone (98.34%, 131 CFU/mL). For smear layer removal, AromaRoot with laser achieved 78.5% open dentinal tubules in the apical third, significantly higher than EDTA alone (64.5%, p < 0.05), though EDTA remained superior in the coronal third (89.0% vs. 81.0%, p > 0.05). Conclusions: The SMART technique significantly improves both disinfection and smear layer removal in root canal therapy, particularly in the apical region. These findings suggest that AromaRoot, especially when laser-activated, may serve as a safe and effective alternative to conventional irrigants, warranting further clinical evaluation. Full article

Accurate preoperative image processing in markerless image-guided surgeries is an important task. However, preoperative planning highly depends on the quality of medical imaging data. In this study, a novel algorithm for outer skin layer extraction from head computed tomography (CT) scans is presented and evaluated. Axial, sagittal, and coronal slices are processed separately to generate spatial data. Each slice is binarized using manually defined Hounsfield unit (HU) range thresholding to create binary images from which valid contours are extracted. The individual points of each contour are then projected into three-dimensional (3D) space using slice spacing and origin information, resulting in uniplanar point clouds. These point clouds are then fused through geometric addition into a single enriched triplanar point cloud. A two-step downsampling process is applied, first at the uniplanar level and then after merging, using a voxel size of 1 mm. Across two independent datasets with a total of 83 individuals, the merged cloud approach yielded an average of 11.61% more unique points compared to the axial cloud. The validity of the triplanar point cloud reconstruction was confirmed by a root mean square (RMS) registration error of 0.848 ± 0.035 mm relative to the ground truth models. These results establish the proposed algorithm as robust and accurate across different CT scanners and acquisition parameters, supporting its potential integration into patient registration for markerless image-guided surgeries. Full article

About ten years ago, we established the first coronagraph that has been continuously operating on the high plateau of western China. This coronagraph is an internal occulting, 10 cm aperture instrument, installed at Lijiang Station through a collaboration with the Norikura Station of the National Astronomical Observatory of Japan. To ensure high efficiency in current and future coronal observations, developing integrated observation systems is essential for reliable, autonomous, and remote operation of coronagraphs. This paper introduces an advanced integrated observation and control system, based on the Lijiang 10 cm coronagraph. The coronagraph focuses on the observations for the solar inner corona, capturing the coronal green-line emission within a field range from $1.03R_{⨀}$ to $2.5R_{⨀}$. To enhance the observational precision and efficiency, a comprehensive integrated system has been designed, incorporating various subsystems, including precise pointing and tracking mechanisms, a multi-band filter system, a protective dome system, and a robust data storage infrastructure. This paper details the hardware architecture and software frameworks supporting each subsystem. Results from extended operational testing confirm the stability of the system, its capacity for autonomous and remote observations, and significant improvements in the automation and efficiency of coronal imaging. The automated observation system will be further improved and used for our future coronagraphs to be developed for coronal magnetism diagnosis. Full article