Search Results (780)

This study demonstrates drift-assisted positron annihilation lifetime spectroscopy on a p-type (100) silicon substrate in a MOS capacitor, using an applied electric field to control the spatial positron distribution prior to annihilation. The device was operated under accumulation, depletion, and inversion conditions, revealing that the internal electric field can drift-transport positrons either toward or away from the SiO₂/Si interface, acting as a diffusion barrier or support, respectively. Key positron drift-transport parameters were derived from lifetime data, and the influence of the non-linear electric field on positron trapping was analyzed. The comparison of the presented results to our previous oxide-side drift experiment on the same metal-oxide–silicon capacitor indicates that the interface exhibits two distinct sides, with different types of defects: void-like and vacancy-like ($P_{\mathrm{b}}$ centers). The positron data also suggest that the charge state of the $P_{\mathrm{b}}$ centers likely varies with the operation mode of the MOS, which affects their positron trapping behavior. Full article

We present a combined ML/NLP (Machine Learning, Natural Language Processing) pipeline for protecting cloud-based APIs (Application Programming Interfaces), which works both at the level of individual HTTP (Hypertext Transfer Protocol) requests and at the access log file reading mode, linking explicitly technical anomalies with business risks. The system processes each event/access log through parallel numerical and textual branches: a set of anomaly detectors trained on traffic engineering characteristics and a hybrid NLP stack that combines rules, TF-IDF (Term Frequency-Inverse Document Frequency), and character-level models trained on enriched security datasets. Their results are integrated using a risk-aware policy that takes into account endpoint type, data sensitivity, exposure, and authentication status, and creates a discrete risk level with human-readable explanations and recommended SOC (Security Operations Center) actions. We implement this design as a containerized microservice pipeline (input, preprocessing, ML, NLP, merging, alerting, and retraining services), orchestrated using Docker Compose and instrumented using OpenSearch Dashboards. Experiments with OWASP-like (Open Worldwide Application Security Project) attack scenarios show a high detection rate for injections, SSRF (Server-Side Request Forgery), Data Exposure, and Business Logic Abuse, while the processing time for each request remains within real-time limits even in sequential testing mode. Thus, the pipeline bridges the gap between ML/NLP research for security and practical API protection channels that can evolve over time through feedback and retraining. Full article

We introduce a new method for preparing a percolation system by employing an inverse percolation model. Unlike standard percolation, where the site occupancy is uniform, the new model imposes a distance-dependent probability of site removal, where sites closer to the lattice center have a higher probability of being removed and are more prone to damage as compared to those at the periphery of the system. The variation in this removal probability is a function of the distance $\left(d\right)$ from the central point. Thus, the central point plays a key role. This is reflected in our effort to model the role of a tumor cell and its surroundings (the tumor microenvironment). The tumor causes a decrease in the concentration of key elements, such as ${\mathrm{O}}_2$ (resulting in hypoxia) and Ca, in the region close to it, which in turn is an impediment to the efficiency of radiotherapy and chemotherapy. This decrease is the largest in sites adjacent to the tumor and smaller away from the tumor. Such change in the concentrations of these elements is vital in the mechanism of cancer therapies. Starting from a fully occupied lattice, we introduce a distance-dependent removal probability $q\left(d\right)$. The value of $q\left(d\right)$ is 1 at and next to the tumor (center) and decreases linearly away from it to a limiting value $q_p$, which is the value of q at the lattice boundaries. We investigate the system properties as a function of $q_p$ and observe a significant decrease in the critical percolation threshold $p_c$ as $q_p$ decreases, falling from the standard value of $p_c=0.5927$ to approximately $p_c=0.20$. Furthermore, we demonstrate that the size of the spanning cluster and the total number of clusters exhibit a strong dependence on $q_p$ as well. Full article

Multi-radar systems can significantly improve tracking robustness and accuracy, but practical deployments are challenged by asynchronous sensing timestamps across distributed platforms and by limited communication bandwidth. This paper proposes a communication-efficient asynchronous track fusion framework based on state and covariance projection. Each radar performs local Kalman filtering and transmits only a compact track message consisting of the posterior state estimate, the associated error covariance, and a timestamp. At the fusion center, a causal reference time is chosen as the latest received timestamp, and all tracks are projected to this common time using a hybrid constant-acceleration (CA)/constant-velocity (CV) motion model with appropriately discretized process noise, followed by information-form (inverse-covariance) fusion. Under standard linear-Gaussian assumptions, the fusion rule is minimum mean square error (MMSE)-optimal when the projected estimation errors are approximately independent. We also analyze the computational complexity and the communication payload of the proposed procedure. Monte Carlo simulations with five heterogeneous radars and random inter-radar time offsets up to 37.5 ms over 100 runs show that the proposed fusion reduces the steady-state range root mean square error (RMSE) by about 66% and the radial-velocity RMSE by about 31% relative to the average single-radar tracker, while maintaining statistical consistency as verified by the normalized estimation error squared (NEES). These results indicate that projection-based track fusion provides an effective accuracy–communication trade-off for asynchronous multi-radar tracking. Full article

Background/Objectives: Pacing-induced cardiomyopathy (PiCM) is a recognized complication of chronic right ventricular pacing (RVP), characterized by left ventricular (LV) dysfunction, adverse remodeling, and progression to heart failure. MicroRNAs (miRs) regulate gene expression and play an important role in ventricular remodeling. This study aimed to observe whether dynamic changes in miRs according to a novel peripheral blood mononuclear cell (PBMC)-based approach could serve as early predictive biomarkers of PiCM. Methods: A prospective, single-center cohort study was conducted in adult patients undergoing pacemaker implantation. Clinical characteristics, echocardiographic parameters and expression levels of miR-208b-3p and miR-9 were assessed immediately and 3 months post-pacemaker implantation. PiCM was defined as a ≥10% reduction in LVEF at one year, with no alternative cause. Statistical analyses included correlation testing, ROC curve analysis, and multivariate regression to identify factors associated with PiCM. Results: Among 126 patients, 11.1% developed PiCM. Compared with the non-PiCM group, those who developed PiCM exhibited more pronounced 3-month changes in miR-208b-3p (median Δ₃log miR: +1.3 vs. −0.4, p = 0.013) and miR-9 (median Δ₃log miR: −1.7 vs. +0.21, p = 0.011). In multivariate analyses, Δ₃LV-GLS, Δ₃logmiR-208b-3p, and Δ₃logmiR-9 were associated with a higher likelihood of PiCM. Among PiCM patients, Δ₃logmiR-208b-3p correlated inversely with Δ₃LV-GLS (r = −0.73, p = 0.016), while Δ₃logmiR-9 correlated positively (r = 0.88, p < 0.001). ROC analyses demonstrated good predictive ability for Δ₃LV-GLS (AUC = 0.924), Δ₃log miR-208b-3p (AUC = 0.783), and Δ₃log miR-9 (AUC = 0.835), with no significant differences between curves. Conclusions: Early LV-GLS deterioration and dynamic changes in expression of miR-208b-3p and miR-9 in PBMCs precede overt LV systolic dysfunction. These miRs may serve as early predictive biomarkers for PiCM. Full article

Background/Objectives: Acute ischemic stroke (AIS) associated with cervical carotid artery pathology remains a therapeutic challenge due to uncertainty regarding emergent carotid artery stenting (eCAS) and the need for intensified antithrombotic therapy, which may increase the risk of hemorrhagic transformation (HT). This retrospective cohort study evaluated the functional and safety outcomes of eCAS within an extended treatment time window. Methods: We analyzed 139 consecutive patients with anterior circulation AIS and large vessel occlusion treated with mechanical thrombectomy between 2019 and 2024. Patients were eligible for MT within 24 h based on clinical–core mismatch (DAWN) or perfusion–core mismatch (DEFUSE 3) criteria. Outcomes were compared between patients treated with eCAS and those undergoing MT without stenting. Results: Twenty-five patients underwent eCAS, predominantly for tandem lesions (80%). Median age was 66 years, median baseline NIHSS was 14, and median infarct core volume on DWI/CTP was 15 mL. Baseline characteristics were comparable between groups, except for the site of occlusion (p < 0.001). A good functional outcome (modified Rankin Scale, mRS 0–2 at 90 days) was observed in 60% of patients in the eCAS group versus 43% in the non-stenting group, without statistical significance (p = 0.067). Rates of parenchymal hematoma (12% vs. 18.4%) and symptomatic intracerebral hemorrhage (8% vs. 3.5%) were similar between groups. Conclusions: In this single-center cohort, eCAS performed in an extended time window did not demonstrate a clear signal of increased hemorrhagic risk. However, residual confounding and imbalance between treatment groups persisted despite the application of inverse probability weighting (IPW), and the findings should be interpreted cautiously. Full article

Background/Objectives: Fluid overload in critically ill patients is linked to adverse outcomes. While resuscitation strategies are well established, guidance for the de-resuscitation phase remains limited. This study aimed to identify clinical factors associated with diuretic response and achieving negative fluid balance (FB) in critically ill patients. Methods: We conducted a single-center, retrospective cohort study of ICU patients who received intravenous furosemide between 2017 and 2023. A CHAID (Chi-square Automatic Interaction Detector) decision tree identified clinical variables associated with fluid removal after the first dose, and a mixed-effects model analyzed repeated measurements. Results: The cohort comprised 1764 patients over 6632 ICU days. Mean arterial pressure (MAP) was the strongest predictor of negative FB. MAP ≤ 75 mmHg yielded minimal negative FB (−33 ± 1054 mL/24 h); MAP 75–90 mmHg yielded intermediate negative FB (−467 ± 1140 mL/24 h); and MAP > 90 mmHg produced the greatest negative FB (−899 ± 1415 mL/24 h; p < 0.001). Secondary associations varied by MAP: creatinine at low MAP, blood urea nitrogen at mid-range MAP, and SOFA score at high MAP, all inversely related to negative FB. In mixed-effects analyses, each 1 mmHg MAP increase was associated with 23.3 mL greater fluid removal (p < 0.001). Independent factors linked to reduced negative FB included vasopressor use (noradrenaline), elevated creatinine, and higher SOFA scores. Conclusions: In this cohort, MAP was significantly associated with the likelihood of achieving a negative fluid balance during de-resuscitation. Conversely, vasopressor use, renal dysfunction, and higher illness severity were linked to reduced diuretic responsiveness. These findings support individualized de-resuscitation strategies. Full article

This study critically examines the relationship between neoliberal environmentalism and green certification systems by quantitatively analyzing LEED-certified buildings in Istanbul. It explores how green building practices intersect with market-oriented urban environmental governance through an analysis of the spatial distribution, ownership types, access typologies, and functional uses of certified projects. The findings reveal that nearly 80% of LEED-certified buildings in Istanbul are developed by private companies, and that 88.6% of these buildings are private spaces with limited or no public access. These projects are predominantly high-end offices or residential developments, with a large share holding “Gold” certification. Correlation analysis identifies an inverse relationship between LEED project density and socioeconomic vulnerability, raising critical questions about spatial justice and equity in access to sustainable urban environments. This study contributes to the growing body of critical literature that frames urban sustainability not merely as a technocratic checklist of standards but as a normative and contested terrain in which justice, equity, and inclusivity must be placed at the center. Full article

Background/Objectives: Sepsis is a life-threatening condition associated with high mortality. Optimal dosing strategies for β-lactam antibiotics in sepsis remain controversial, particularly in patients with renal impairment. Cefepime (CFPM) is widely used as empiric therapy; however, its appropriate initial dosing in critically ill patients is unclear. This study aimed to evaluate whether high-dose CFPM administration during the first 48 h improves survival in patients with sepsis, irrespective of renal function. Methods: This single-center, retrospective, observational study included adult intensive care unit (ICU) patients with sepsis who received CFPM as initial therapy between January 2017 and December 2024. Patients were categorized into High-dose (12 g within 48 h; 2 g every 8 h) and Low-dose (<12 g/48 h) groups. The primary outcome was ICU survival. To address confounding, inverse probability of treatment weighting (IPTW) based on serum creatinine was applied, with sensitivity analyses using 1% trimmed and stabilized IPTW. Results: Of 122 eligible patients, 84 were analyzed (High-dose: n = 27; Low-dose: n = 57). After IPTW adjustment, high-dose CFPM was significantly associated with improved ICU survival (odds ratio [OR] 5.43, 95% confidence interval [CI] 1.60–18.39, p = 0.0066). This association remained consistent in the 1% trimmed IPTW analysis (OR 4.07, 95% CI 1.19–13.97, p = 0.0256). Stabilized IPTW yielded a similar effect estimate, though without statistical significance (OR 5.43, 95% CI 0.72–41.16, p = 0.1017). Overall, results were consistent in direction and magnitude across models. Conclusions: High-dose CFPM administration during the initial 48 h was associated with improved ICU survival in patients with sepsis, independent of renal function. Full article

Previous studies on single-polarized InSAR-based sub-canopy topography inversion have mainly relied on simplified or empirical models that only consider the volume scattering process. In a boreal forest area, the canopy layer is often discontinuous. In such a case, the radar backscattering echoes are mainly dominated by ground surface and volume scattering processes. However, interferometric scattering models like Random Volume over Ground (RVoG) have been little utilized in the case of single-polarized InSAR. In this study, we propose a novel method for retrieving sub-canopy topography by combining the RVoG model with multi-baseline InSAR data. Prior to the RVoG model inversion, a SAR-based dimidiate pixel model and a coherence-based penetration depth model are introduced to quantify the initial values of the unknown parameters, thereby minimizing the reliance on external vegetation datasets. Building on this, a nonlinear least-squares algorithm is employed. Then, we estimate the scattering phase center height and subsequently derive the sub-canopy topography. Two frames of multi-baseline TanDEM-X co-registered single-look slant-range complex (CoSSC) data (resampled to 10 m × 10 m) over the Krycklan catchment in northern Sweden are used for the inversion. Validation from airborne light detection and ranging (LiDAR) data shows that the root-mean-square error (RMSE) for the two test sites is 3.82 m and 3.47 m, respectively, demonstrating a significant improvement over the InSAR phase-measured digital elevation model (DEM). Furthermore, diverse interferometric baseline geometries and different initial values are identified as key factors influencing retrieval performance. In summary, our work effectively addresses the limitations of the traditional RVoG model and provides an advanced and practical tool for sub-canopy topography mapping in forested areas. Full article

Additive manufacturing technologies for metals are developing rapidly. Among them, wire arc additive manufacturing (WAAM) has become widespread due to its accessibility. However, parts produced using WAAM require surface post-processing; therefore, hybrid technologies have emerged that combine additive and subtractive processes within a single compact manufacturing complex. Such systems make it possible to organize single-piece and small-batch production, including for the repair and restoration of equipment in remote areas. For this purpose, hybrid equipment must be lightweight, compact for transportation, provide sufficient workspace, and be capable of folding for transport. This paper proposes the concept of a multifunctional metal 3D printer based on hybrid technology, where WAAM is used for printing, and mechanical post-processing is applied to obtain finished parts. To ensure both rigidity and low mass, a 3-UPU parallel manipulator and a worktable with two rotational degrees of freedom are employed, enabling five-axis printing and machining. The printer housing is foldable for convenient transportation. The kinematics of the proposed 3D printer are investigated as an integrated system. Forward and inverse kinematics problems are solved, the velocities and accelerations of the moving platform center are calculated, singular configurations are analyzed, and the workspace of the printer is determined. Full article

Background/Objectives: Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant vascular dysplasia characterized by recurrent epistaxis, anemia, and visceral arteriovenous malformations. Epistaxis is the most frequent and disabling manifestation, with limited effective pharmacological options. Propranolol, a non-selective beta-blocker with vasoconstrictive and antiangiogenic properties, has shown benefit in other vascular anomalies but remains scarcely studied in HHT. This study aimed to evaluate the effect of oral propranolol on nasal bleeding in patients with HHT. Methods: A retrospective observational study including 151 adults with HHT (44 treated with propranolol, 107 untreated) was conducted using data from an Institutional HHT Registry from a referral center. Baseline demographic and clinical variables were recorded. Outcomes at 6 months included changes in hemoglobin, adherence to nasal hygiene, use of bleeding-related therapies, and improvement in epistaxis frequency and intensity according to the Sadick–Bergler scale. Logistic regression models were adjusted for confounders and indication bias using inverse probability of treatment weighting (IPTW). Results: After IPTW adjustment, propranolol was significantly associated with reduced frequency of epistaxis (adjusted OR: 3.8; 95% CI: 1.3–11.2; p = 0.016), while no effect was observed on intensity. Hemoglobin levels increased modestly in both groups without a significant difference. Patients without propranolol showed greater antifibrinolytic use, whereas adherence to nasal care remained stable among treated patients. Conclusions: Oral propranolol reduced nasal bleeding frequency in HHT, even among patients with greater baseline severity. Given its accessibility, safety, and potential to lessen treatment burden, it may represent a valuable adjunct therapy. This study represents the largest cohort of HHT patients treated with propranolol reported to date. Randomized trials including standardized bleeding scores and patient-reported outcomes are warranted to confirm clinical and quality-of-life benefits. Full article

Background and Objectives: Pancreatoduodenectomy (PD) is the primary treatment for patients with resectable, non-metastatic pancreatic adenocarcinoma and periampullary tumors. Although surgical methods and perioperative management have improved, the procedure still carries a high risk of complications, with postoperative pancreatic fistula (POPF) being the most significant. This study focuses on identifying current risk factors for POPF after PD in a single HPB center. Materials and Methods: We retrospectively analyzed prospectively collected data from patients undergoing PD in our department between October 2018 and April 2024. Data included demographics, comorbidities, lifestyle factors, preoperative tests (bilirubin, CA19-9, HbA1c), intraoperative variables (pancreatic texture, duct diameter), and postoperative outcomes. POPF was classified using the International Study Group of Pancreatic Surgery (ISGPS) criteria. Univariate and multivariate logistic regression analyses were performed. Results: A total of 118 patients underwent PD (82 males, 36 females; mean age 67 (45–85) years; mean body mass index (BMI) 26.6 kg/m²). POPF occurred in 37 patients (31%), with 27 Grade B (23%) and 10 Grade C (9%). The 30- and 90-day mortality rates were 5% and 12.7%, respectively. Univariate analysis showed associations between POPF and soft pancreas (p = 0.018), c-reactive protein (CRP) on postoperative day (POD) 5 (p = 0.004), and serum amylase on POD 0 (p = 0.008). Diabetes mellitus was associated with a lower incidence of POPF (p = 0.014). Multivariate analysis confirmed CRP on POD 5 (OR 1.007, p = 0.025) and DM (OR 0.254, p = 0.015), as independent factors. ROC analysis identified POD 0 amylase >113.5 U/L (AUC 0.717) and POD 5 CRP >125.3 mg/dL (AUC 0.669) as predictive values. Conclusions: POPF remains an important complication after PD. CRP > 126 mg/dL on POD 5 was associated with POPF and may serve as an adjunctive signal to guide further assessment, including imaging. The observed inverse association with diabetes mellitus is hypothesis-generating and should be interpreted cautiously, considering potential confounding and the influence of center volume, surgeon heterogeneity, and institutional protocols. Full article

Fulgides are a class of organic compounds that exhibit photochromic behavior in both the solid state and in solution. These compounds have attracted considerable research interest due to their wide range of potential applications, including photochromic eyewear, smart windows, optical switches, data storage, and chemical and biological sensors. Here, we report the synthesis and crystal structures of fulgides bearing four different para-substituents on the phenyl moiety. All four molecules crystallize in space groups containing an inversion center. The distances between the two carbon atoms that would form the single C–C bond in the cyclized products fall within the range of 3.301–3.475 Å. The observed structural variations are attributed to intermolecular interactions based on Hirshfeld surface analysis. The fulgides exhibit photochromism, but they are not expected to display ferroelectric behavior due to their crystallization in centrosymmetric space groups. Full article

Background/Objectives: Teledermatology has transformed access to dermatologic care, yet its association with melanoma prognostic parameters and diagnostic pathways in tertiary settings remains incompletely characterized. To compare the clinicopathologic profile of melanomas diagnosed under face-to-face consultation (2019) versus teledermatology-based referral (teleconsultation) (2022). Methods: A retrospective observational study comparing two patient cohorts: those diagnosed with melanoma via in-person consultation in 2019, and those diagnosed through teleconsultation in 2022. These years were selected to reflect the structural shift in care delivery models before and after the COVID-19 pandemic, during which teledermatology was formally implemented. Sociodemographic, clinical, and histopathological variables were collected. A multivariable logistic regression model assessed variables associated with being diagnosed in the 2022 teledermatology cohort versus the 2019 face-to-face cohort. Statistical analyses were performed using R (v. 4.4.3). Results: A total of 151 patients were included (89 in-person in 2019, 62 via teleconsultation in 2022). Multivariable analysis identified three variables independently associated with being diagnosed via teleconsultation. Increasing Breslow thickness was inversely associated with teleconsultation diagnosis (OR 0.60 per 1 mm increase; 95% CI 0.40–0.91; p= 0.017). Similarly, the presence of histologic regression (OR 0.28; 95% CI 0.09–0.90; p = 0.032) and immunosuppression (OR 0.08; 95% CI 0.008–0.86; p = 0.037) were inversely associated with teleconsultation diagnosis. No significant associations were found for sex, age, tumor location, ulceration, mitosis, or clinical stage. Conclusions: In this retrospective single-center comparison of two care models, melanomas diagnosed through teleconsultation in 2022 were associated with a more favorable clinicopathologic profile at diagnosis than those diagnosed via face-to-face consultation in 2019. These findings support the role of teledermatology-based referral pathways in facilitating timely melanoma assessment, although causal inference is limited by the observational design. Full article