Search Results (597)

Background and Objectives: Functional capacity assessment is essential in bariatric surgery candidates, but the Six-Minute Walk Test (6MWT) may be limited by fatigue, joint pain, and spatial constraints in individuals with severe obesity. Shorter tests such as the Two-Minute Walk Test (2MWT), Three-Minute Walk Test (3MWT), and One-Minute Sit-to-Stand Test (1MSTS) have been proposed as alternatives, yet comparative data in this population remain scarce. We aimed to evaluate the validity, reliability, and clinical utility of the 2MWT, 3MWT, and 1MSTS as substitutes for the 6MWT in patients preparing for bariatric surgery. Materials and Methods: In this cross-sectional study, 142 obese adults (BMI ≥ 30 kg/m²) underwent standardized 2MWT, 3MWT, 6MWT, and 1MSTS protocols. Correlation, linear regression, test–retest reliability (ICC), and ROC analyses were used to determine each test’s correlation and discriminative accuracy for impaired exercise tolerance (6MWT < 450 m). Results: The 3MWT showed the strongest correlation with the 6MWT (r = 0.930) and the highest explained variance (R² = 0.865), especially in individuals with BMI > 50. It also exhibited excellent reliability (ICC > 0.9) and a strong ROC profile (AUC = 0.931; 212 m cut-off). The 2MWT demonstrated acceptable concurrent validity but slightly lower agreement. The 1MSTS showed weak and inconsistent associations with 6MWT performance, suggesting limited value in assessing aerobic capacity in this population. Conclusions: The 3MWT appears to be a valid, reliable, and clinically practical alternative to the 6MWT in individuals with severe obesity. The 2MWT may be used when time or patient tolerance is limited. The 1MSTS, while safe and simple, may reflect strength and coordination more than aerobic capacity, limiting its utility in this context. Full article

Background: The Malnutrition Screening Tool (MST) is commonly used to identify malnutrition risk; however it has demonstrated poor sensitivity to detect malnutrition in inpatients with chronic kidney disease (CKD) and kidney replacement therapy (KRT) populations. Gastrointestinal symptoms, such as poor appetite, may better detect malnutrition. The accuracy of MST or other nutrition-related parameters to detect malnutrition in ambulatory patients with CKD stages 4–5 without KRT has not been evaluated. Methods: A single site retrospective audit of outpatient records from May 2020 to March 2025 was conducted. Patients with eGFR < 25 mL/min/1.73 m² without KRT who had both MST and a 7-point Subjective Global Assessment (SGA) within 7 days were included. Sensitivity, specificity, and ROC-AUC analyses compared nutritional parameters against SGA-defined malnutrition. Nutritional parameters tested included MST, hand grip strength, upper gastrointestinal symptom burden, poor appetite and a combination of some of these parameters. Results: Among 231 patients (68.8% male, median age 69 years, median eGFR 15), 29.9% were at risk of malnutrition (MST ≥ 2) and 33.8% malnourished (SGA ≤ 5). All potential screening tools had AUC ranging from 0.604 to 0.710, implying a poor-to-moderate discriminator ability to detect malnutrition. Combining HGS ≤ 29.5 kg or MST ≥2 demonstrated high sensitivity (95.5%) and negative predictive value (93.3%), but low specificity (33.3%) for detecting malnutrition, indicating this approach is effective for ruling out malnutrition but may over-identify at-risk individuals. Conclusions: MST and other tested tools showed limited overall accuracy to identify malnutrition. Using combined nutritional markers of HGS or MST score was the most sensitive tool for detecting malnutrition in this advanced CKD without KRT population. Full article

Polar Mesosphere Winter Echoes (PMWEs) are relatively strong radar echoes from 50–80 km altitudes observed at a broad frequency range, at polar latitudes, mainly during equinox and winter seasons. Most PMWEs can be explained by neutral air turbulence creating structures in the mesosphere and enhanced electron density. We have studied the characteristics of PMWEs and their dependence on solar and geophysical conditions using the ESrange RADar (ESRAD) located in northern Sweden during 1996–2021. We found that PMWEs start in mid-August and finish in late May. The mean daily occurrence rate varied significantly during the PMWE season, showing several relative maxima and a minimum in December. The majority of PMWEs were observed during sunlit hours at 60–75 km. Some echoes were detected at 50–60 km. The echo occurrence rate showed a pronounced maximum near local noon at 64–70 km. During nighttime, PMWEs were observed at about 75 km. PMWEs were observed on 47% of days with disturbed conditions (enhanced solar wind speed, K_p index, solar proton, and X-ray fluxes), and on only 14% of days with quiet conditions. Elevated solar wind speed and K_p index each accounted for 30% of the days with PMWE detections. Full article

Urban Air Mobility (UAM) is envisioned to revolutionize urban transportation by improving traffic efficiency and mitigating surface-level congestion. One of the fundamental challenges in implementing UAM systems lies in the optimal siting of vertiports, which requires a delicate balance among infrastructure construction costs, passenger access costs to their assigned vertiports, and the operational connectivity of the resulting vertiport network. This study develops an integrated mathematical model for vertiport location decision, aiming to minimize total system cost while ensuring UAM network connectivity among the selected vertiport locations. To efficiently solve the problem and improve solution quality, a hybrid genetic algorithm is developed by incorporating a Minimum Spanning Tree (MST)-based connectivity enforcement mechanism, a fundamental concept in graph theory that connects all nodes in a given network with minimal total link cost, enhanced by a greedy initialization strategy. The effectiveness of the proposed algorithm is demonstrated through numerical experiments conducted on both synthetic datasets and the real-world transportation network of New York City. The results show that the proposed hybrid methodology not only yields high-quality solutions but also significantly reduces computational time, enabling faster convergence. Overall, this study provides practical insights for UAM infrastructure planning by emphasizing demand-oriented vertiport siting and inter-vertiport connectivity, thereby contributing to both theoretical development and large-scale implementation in complex urban environments. Full article

In many applications, including underwater robotics, the coverage problem requires an autonomous vehicle to systematically explore a defined area while minimizing redundancy and avoiding obstacles. This paper investigates coverage path-planning strategies to enhance the efficiency of underwater gliders particularly in maximizing the probability of detecting a radioactive source while ensuring safe navigation. We evaluate three path-planning approaches: the Traveling Salesman Problem (TSP), Minimum Spanning Tree (MST), and the Optimal Control Problem (OCP). Simulations were conducted in MATLAB R2020a, comparing processing time, uncovered areas, path length, and traversal time. Results indicate that the OCP is preferable when traversal time is constrained, although it incurs significantly higher computational costs. Conversely, MST-based approaches provide faster but fewer optimal solutions. These findings offer insights into selecting appropriate algorithms based on mission priorities, balancing efficiency and computational feasbility. Full article

The absence of skin color information in skin cancer datasets poses a significant challenge for accurate diagnosis using artificial intelligence models, particularly for non-white populations. In this paper, based on the Monk Skin Tone (MST) scale, which is less biased than the Fitzpatrick scale, we propose MST-AI, a novel method for detecting skin color in images of large datasets, such as the International Skin Imaging Collaboration (ISIC) archive. The approach includes automatic frame, lesion removal, and lesion segmentation using convolutional neural networks, and modeling normal skin tones with a Variational Bayesian Gaussian Mixture Model (VB-GMM). The distribution of skin color predictions was compared with MST scale probability distribution functions (PDFs) using the Kullback-Leibler Divergence (KLD) metric. Validation against manual annotations and comparison with K-means clustering of image and skin mean RGBs demonstrated the superior performance of the MST-AI, with Kendall’s Tau, Spearman’s Rho, and Normalized Discounted Cumulative Gain (NDGC) of 0.68, 0.69, and 1.00, respectively. This research lays the groundwork for developing unbiased AI models for early skin cancer diagnosis by addressing skin color imbalances in large datasets. Full article

Brucellosis remains endemic in Tunisia, causing abortions in small ruminants, and represents a public health threat through occupational exposure and the consumption of contaminated animal products. The aims of this study are to assess the antibiotic susceptibility of two Brucella melitensis isolates (TATA and SBZ) from aborted sheep, to analyze their genomes using hybrid whole-genome sequencing, and to investigate their antimicrobial resistance (AMR), potential virulence factors (VFs), and phylogenetic relationships. Both isolates were phenotypically confirmed to be susceptible to doxycycline, gentamicin, rifampicin, streptomycin, and trimethoprim–sulfamethoxazole, and no corresponding classical AMR genes were identified. However, several potential AMR-related genes (mprF, bepCDEFG, qacG, and adeF) and a mutation in the parC gene were detected. The analysis of the genotypes revealed 74 potential virulence genes, primarily involved in lipopolysaccharide synthesis and type IV secretion systems. Genomic comparison showed over 99% nucleotide identity between the Tunisian strains, B. melitensis bv. 1 16M and B. melitensis bv. 3 Ether. Five gene clusters, including three hypothetical proteins with 100% identity, were detected exclusively in the TATA and SBZ strains. Additionally, two unique gene clusters were identified in SBZ: a rhodocoxin reductase and another hypothetical protein. Both isolates were assigned to sequence types ST11 and ST89. Core-genome-based phylogenetic analysis clustered both strains with biovar 3 and ordered the Tunisian strains into two distinct groups: TATA within Tunisian Cluster 1 is closely related to strains from Egypt and Italy, while SBZ near MST Cluster 4 is more related to isolates from Austria and two outliers from Italy and Tunisia. This study provides the first genomic characterization of B. melitensis from aborted sheep in Tunisia and offers valuable insights into AMR, virulence, and phylogenetic distribution. Full article

Accurately reconstructing tree skeletons from multi-view images is challenging. While most existing works use skeletonization from 3D point clouds, thin branches with low-texture contrast often involve multi-view stereo (MVS) to produce noisy and fragmented point clouds, which break branch connectivity. Leveraging the recent development in accurate mask extraction from images, we introduce a mask-guided graph optimization framework that estimates a 3D skeleton directly from multi-view segmentation masks, bypassing the reliance on point cloud quality. In our method, a skeleton is modeled as a graph whose nodes store positions and radii while its adjacency matrix encodes branch connectivity. We use 3D Gaussian splatting (3DGS) to render silhouettes of the graph and directly optimize the nodes and the adjacency matrix to fit given multi-view silhouettes in a differentiable manner. Furthermore, we use a minimum spanning tree (MST) algorithm during the optimization loop to regularize the graph to a tree structure. Experiments on synthetic and real-world plants show consistent improvements in completeness and structural accuracy over existing point-cloud-based and heuristic baseline methods. Full article

Mitochondria are currently of great interest to scientists. The role of mitochondrial DNA (mtDNA) mutations has been proven in the genesis of more than 200 pathologies, which are called mitochondrial disorders. Therefore, the study of mitochondria and mitochondrial DNA is of great interest not only for understanding cell biology but also for the treatment and prevention of many mitochondria-related pathologies. There are two main trends of mitochondrial therapy: mitochondrial replacement therapy (MRT) and mitochondrial transplantation therapy (MTT). Also, there are two main categories of MRT based on the source of mitochondria. The heterologous approach includes the following methods: pronuclear transfer technique (PNT), maternal spindle transfer (MST), Polar body genome transfer (PBT) and germinal vesicle transfer (GVT). An alternative approach is the autologous method. One promising autologous technique was the autologous germline mitochondrial energy transfer (AUGMENT), which involved isolating oogonial precursor cells from the patient, extracting their mitochondria, and then injecting them during ICSI. Transmission of defective mtDNA to the next generation can also be prevented by using these approaches. The development of a healthy child, free from genetic disorders, and the prevention of the occurrence of lethal mitochondrial disorders are the main tasks of this method. However, a number of moral, social, and cultural objections have restricted its exploration, since humanity first encountered the appearance of a three-parent baby. Therefore, this review summarizes the causes of mitochondrial diseases, the various methods involved in MRT and the results of their application. In addition, a new technology, mitochondrial transplantation therapy (MTT), is currently being actively studied. MTT is an innovative approach that involves the introduction of healthy mitochondria into damaged tissues, leading to the replacement of defective mitochondria and the restoration of their function. This technology is being actively studied in animals, but there are also reports of its use in humans. A bibliographic review in PubMed and Web of Science databases and a search for relevant clinical trials and news articles were performed. A total of 81 publications were selected for analysis. Methods of MRT procedures were reviewed, their risks described, and the results of their use presented. Results of animal studies of the MTT procedure and attempts to apply this therapy in humans were reviewed. MRT is an effective way to minimize the risk of transmission of mtDNA-related diseases, but it does not eliminate it completely. There is a need for global legal regulation of MRT. MTT is a new and promising method of treating damaged tissues by injecting the body’s own mitochondria. The considered methods are extremely good in theory, but their clinical application in humans and the success of such therapy remain a question for further study. Full article

Background: Patellar resection is recommended in cases of massive cortical bone disruption or malignancies. Modern literature lacks a consensus surgical reconstruction after total patellectomy. Our study reviews the surgical techniques described in the literature and summarizes the reported functional outcomes and complication rates. Materials: We systematically reviewed the existing literature, searching the PubMed, Embase, and Scopus databases for articles published between 1950 and 2024. We recorded age, diagnosis, tumor size, Lodwick classification, soft tissue involvement, and pre-operative fractures for each case or case series. We also recorded the reconstructive approaches. Complications, local recurrences, MSTS scores, and knee range of motion (ROM) were considered when reported. Results: Twenty-eight articles met our inclusion criteria. Among these, 4 were case series and 24 were case reports. A total of 47 cases treated with total patellectomy were reviewed. Reconstruction was performed with direct suture in 8 cases, while 17 had local augments, including allograft (10 cases), muscle flaps or transportations (4), autologous bone (1), or a composite (2). Reconstruction was not mentioned in 22 cases. ROM was reported for 17 cases, and the MSTS score was reported for 9 cases. Conclusions: In cases of relatively small tissue defects, a direct suture of the extensor apparatus can allow adequate functional recovery. In cases of larger gaps, surgeons should use muscle flaps, transfers, or soft tissue augments. Massive bone and tendon allografts should mainly be considered in cases where the neoplasm was not confined to the patella but extensively involved the patellar ligament or the quadriceps tendon. Full article

Background: Primary malignant bone tumors among adolescent patients are most commonly associated with burdensome surgeries that can severely affect young patients’ early life. To this day, despite available autologous tissue donor sites, cement spacers or endoprostheses are still most commonly used as a form of reconstruction of post-resection defects. Methods: The study group includes 20 adolescent patients diagnosed with Osteosarcoma or Ewing Sarcoma involving the upper limbs. The inclusion criteria were as follows: primary malignant bone tumors sensitive to neoadjuvant chemotherapy, tumors not infiltrating major blood vessels and nerves, and the appliance of the microsurgical free flap as a reconstructive method. Poor tumor response to neodajuvant chemotherapy or patients with incomplete follow-up were excluded from this study. To achieve the functional reconstruction of post-resection defects, fibula free flaps were applied. In cases of resection, including the metaphysis of a long bone, a modification of the flap harvest was applied in order to prevent arthrodesis. The MSTS (Musculoskeletal Tumor Society Scoring System) scale was used as a functional outcome measurement tool. Results: The reported outcomes of this study prove the efficiency of the treatment’s approach of combining the resection of the tumor with subsequent microsurgical restoration with the use of autologous tissues. The average score on the MSTS scale, which assesses the functional outcome, was 26.8/30 points, which indicates great motor outcomes. There were no reports of local recurrence during follow-up. Conclusions: Patients with primary malignant bone tumors in the upper limbs can benefit from microsurgical techniques, which are highly customized; effective; and give sufficient functionality following extensive resection. Full article

This study aims to investigate the mechanism by which the total flavones of Rhododendron (TFR) protect against cerebral ischemic injury through the endothelial-derived H₂S-mediated regulation of RhoA phosphorylation at the Ser188 and Rho kinase 2 (ROCK₂) phosphorylation at Thr436. For experimental design, mouse or rat cerebrovascular endothelial cells (ECs) were cultured with or without neurons and subjected to hypoxia/reoxygenation (H/R) injury. The vasodilation of the cerebral basilar artery was assessed. Cerebral ischemia/reperfusion (I/R) injury was induced in mice by bilateral carotid artery ligation, followed by Morris water maze and open field behavioral assessments. The protein levels of cystathionine-γ-lyase (CSE), 3-mercaptopyruvate sulfurtransferase (3-MST), RhoA, ROCK₂, p-RhoA (RhoA phosphorylated at Ser188), and p-ROCK₂ (ROCK₂ phosphorylated at Thr436) were quantified. Additionally, the activities of RhoA and ROCK₂ were measured. Notably, TFR significantly inhibited H/R-induced H₂S reduction and suppressed the increased expression and activity of RhoA and ROCK₂ in ECs, effects attenuated by CSE or 3-MST knockout. Moreover, TFR-mediated cerebrovascular dilation was reduced by RhoA or ROCK₂ inhibitors, while the protective effect of TFR against cerebral I/R injury in mice was markedly attenuated by the heterozygous knockout of ROCK₂. In the ECs-co-cultured neurons, the inhibition of TFR on H/R-induced neuronal injury and decrease in H₂S level in the co-culture was attenuated by the knockout of CSE or 3-MST in the ECs. TFR notably inhibited the H/R-induced upregulation of neuronal RhoA, ROCK₂, and p-ROCK₂ protein levels, as well as the activities of RhoA and ROCK₂, while reversing the decrease in p-RhoA. However, the knockout of CSE or 3-MST in the ECs significantly attenuated the inhibition of TFR on these increases. Furthermore, 3-MST knockout in ECs attenuated the TFR-mediated suppression of p-RhoA reduction. Additionally, CSE or 3-MST knockout in ECs exacerbated H/R-induced neuronal injury, reduced H₂S level in the co-culture system, and increased RhoA activity and ROCK₂ expression in neurons. In summary, TFR protected against ischemic cerebral injury by endothelial-derived H₂S promoting the phosphorylation of RhoA at Ser188 but inhibited the phosphorylation of ROCK₂ at Thr436 to inhibit the RhoA-ROCK₂ pathway in neurons. Full article

Background/Objectives: Previous studies have reported satisfactory outcomes and low rates of instrumentation-related complications (IRCs) following nonfusion posterior fixation in patients with metastatic spinal tumors (MSTs). However, to adequately assess the longevity and durability of nonfusion instrumentation in patients with longer life expectancy, an extended follow-up period is essential. This study aims to evaluate the incidence of and risk factors for IRCs in patients with MSTs who underwent nonfusion posterior fixation and had radiographic follow-up data available for at least one year postoperatively. Methods: Consecutive data were collected from patients who underwent pedicle screw-based posterior fixation without fusion for MSTs in the thoracic and/or lumbar region from 2005 to 2018. The IRCs included screw loosening, screw pull-out, and metal breakage. The IRC-free survival and related factors were analyzed by Kaplan–Meier survivorship analysis with the log-rank test within a minimum follow-up period of one year. A multivariate analysis was performed using a Cox proportional-hazards regression model. Results: In total, 61 patients were included. The mean follow-up period was 28.3 months (range: 12.0–102.6 months). There were 27 cases (44.2%) of IRCs, including 22 cases of screw loosening, four cases of screw pull-out, and one case of rod breakage, at an average of 9.6 months (range: 1.0–38.1 months). The median IRC-free survival was 38.1 months (range: 1.0–102.6 months). Only three patients experienced pain aggravation with IRCs. No revision surgery was performed. A multivariate analysis identified that fixation length was a risk factor for IRCs (odds ratio: 0.358, 95% confidence interval: 0.114–0.888; p = 0.027). Conclusions: IRCs are frequent but mostly asymptomatic after nonfusion posterior fixation in patients with MSTs followed up for at least one year. Overall, the IRC-free survival was long enough considering the patient survival. Fixation length was a significant risk factor for IRCs regardless of MST location. Full article

The Ice, Cloud, and land Elevation Satellite-2 has provided unprecedented global surface elevation measurements through photon-counting Lidar (Light detection and ranging), yet its low signal-to-noise ratio (SNR) poses significant challenges for denoising algorithms. Existing methods, relying on fixed parameters, struggle to adapt to dynamic noise distribution in rugged mountain regions where signal and noise change rapidly. This study proposes an adaptive Bayesian denoising algorithm integrating minimum spanning tree (MST) -based slope estimation and probabilistic parameter optimization. First, a simulation framework based on ATL03 data generates point clouds with ground truth labels under varying SNRs, achieving correlation coefficients > 0.9 between simulated and measured distributions. The algorithm then extracts surface profiles via MST and coarse filtering, fits slopes with >0.9 correlation to reference data, and derives the probability distribution function (PDF) of neighborhood photon counts. Bayesian estimation dynamically selects optimal clustering parameters (search radius and threshold), achieving F-scores > 0.9 even at extremely low SNR (1 photon/10 MHz noise). Validation against three benchmark algorithms (OPTICS, quadtree, DRAGANN) on simulated and ATL03 datasets demonstrates superior performance in mountainous terrain, with precision and recall improvements of 10–20% under high noise conditions. This work provides a robust framework for adaptive parameter selection in low-SNR photon-counting Lidar applications. Full article

Thymic epithelial tumors (TETs) display heterogeneous histology and often unpredictable clinical behavior. The Hippo signaling pathway has been implicated in tumorigenesis, but its role in TETs remains poorly characterized. We performed the first comprehensive immunohistochemical analysis of core and upstream Hippo pathway components—YAP1, active YAP (AYAP), TAZ, LATS1, MOB1A, MST1, SAV1, and TEAD4—in 77 TETs. Associations with clinicopathological parameters and survival were explored. We observed widespread expression of Hippo components in TETs with significant associations among molecules and differences in subcellular localization and expression in normal tissue. Early stage TETs showed higher nuclear YAP1 (p = 0.032) and AYAP (p = 0.007), while cytoplasmic MST1 (p = 0.002), LATS1 (p = 0.007), MOB1A (p = 0.033) and TEAD4 (p < 0.001) correlated with advanced stage. Cytoplasmic MST1 (p = 0.014), LATS1 (p < 0.001) and TEAD4 (p = 0.005) were associated with histological aggressiveness. Cytoplasmic TEAD4 overexpression was associated with poorer overall survival (log-rank, <70% versus ≥70%, p = 0.003). Our findings provide novel insights into the differential regulation and compartmentalization of Hippo components in TETs. While indolent tumors show features that are consistent with partial Hippo inactivation, more aggressive phenotypes exhibit reduced nuclear YAP/TAZ and altered TEAD4 compartmentalization, suggesting a context-dependent Hippo signaling state. Cytoplasmic TEAD4 emerges as a potential adverse prognosticator, indicating involvement in non-canonical or Hippo-independent mechanisms. Full article