Search Results (395)

Graphene oxide (GO) has been widely investigated as a nanoreinforcement for cementitious composites; however, its effectiveness depends on stable dispersion within the highly alkaline, calcium-rich environment of fresh cement paste. This study evaluates the dispersion behaviour of GO in deionised (DI) water and saturated calcium hydroxide (Ca(OH)₂) under controlled conditions and assesses the effectiveness of anionic and cationic surfactants in both environments. GO was synthesised using the modified Hummers method and verified by comprehensive physicochemical characterisation. Dispersion stability was assessed using UV-Vis spectroscopy at GO concentrations of 0.04–0.08 mg/mL in DI water, and the 0.08 mg/mL system was further studied in saturated Ca(OH)₂ with and without sodium dodecylbenzene sulphonate (SDBS) and cetyltrimethylammonium bromide (CTAB) at a 1:1 mass ratio. Zeta potential and dynamic light scattering measurements were performed to understand the relation between the surface charge and agglomeration of GO. In DI water, GO retained close to 70% of its initial absorbance after 60 min, and both surfactants improved retention to above 90%. In saturated Ca(OH)₂, retention fell to approximately 40%, and neither surfactant restored stability despite producing zeta values that would conventionally support stable dispersion. The findings indicate that GO aggregation in calcium ion (Ca²⁺)-rich alkaline environments is not governed by net surface charge alone, consistent with the established mechanism of Ca²⁺ chemical cross-linking with GO carboxyl groups. Full article

Seismic Shake-e is a free app that provides valuable data and tools related to earthquakes, covering the stages before, during, and after seismic events. In this text, we describe the main features of the Seismic Shake-e 2.1 (SSe) app, the considerations that guided its development, examples of its use, and the challenges for future versions. Version 1.0 of this app was awarded as one of the winners of EOVALUE: Call for Innovative Apps in environmental and social fields, a project by the Joint Research Centre (JRC), the European Commission’s science and knowledge service. SSe recognizes two user levels: basic and intermediate/advanced. There are six modules for each level. The main topics of these modules for both user types are: (1) Accelerometer Networks (AN), (2) Seismograms Analyzer-e (SAe), (3) Seismic Design of Buildings (SDB), (4) Earthquake Preparedness (EP), (5) Earthquake Early Warning Systems (EEWS) & Tsunami Warning Systems (TWS), and (6) Earthquake Emergency Response & Recovery. The two key modules are AN and SAe: the first explains how to obtain seismic records, and the second provides tools for their analysis. We include some applications of SSe, along with their results and discussion. We also list the advantages of the main modules and discuss potential future developments and improvements. The uniqueness of this work is that we highlight the software’s essential features and demonstrate its applications. Full article

Electrokinetic-Permeable Reactive Barrier (EK-PRB) technology can effectively remediate heavy metal-contaminated soil, and the properties of PRB materials play an important role in determining the remediation efficiency. To select a suitable PRB material, montmorillonite (MMT) was modified using cetyltrimethylammonium bromide (CTAB), sodium dodecylbenzenesulfonate (SDBS), and cocamidopropyl betaine (CAB), respectively; their remediation efficiencies for soils co-contaminated with Zn²⁺, Pb²⁺, and Cd²⁺ were then compared within an EK-PRB system. The results indicated that remediation efficacy varied significantly depending on the heavy metal and the surfactant used for modification. After 7 days of remediation, SDBS-modified MMT achieved the highest Zn²⁺ removal efficiency (49.65%), whereas CTAB-modified MMT showed optimal removal performance for both Pb²⁺ (38.03%) and Cd²⁺ (76.02%). When the remediation time was extended to 14 days, SDBS-modified MMT attained the highest removal efficiencies for Zn²⁺ (69.80%) and Pb²⁺ (69.50%), while CTAB-modified MMT maintained superior Cd²⁺ removal performance (86.94%). Energy consumption analysis showed that both CAB- and SDBS-modified MMT reduced energy consumption moderately compared with the unmodified control, whereas CTAB modification resulted in a substantial increase in energy demand. Experimental results confirm that surfactant-modified MMT effectively optimizes the EK-PRB remediation. A comprehensive evaluation considering both removal efficiency and energy consumption identified SDBS-MMT as the optimal material. The optimized EK-PRB parameters established in this study provide theoretical and technical support for the remediation of soils co-contaminated with multiple heavy metals. Full article

Constructing efficient conductive networks in flexible polymer matrices remains a central challenge in electromagnetic interference (EMI) shielding material design. In this work, a ‘point-line’ hybrid filler system combining conductive carbon black (CB) and multi-walled carbon nanotubes (MWCNTs) was incorporated into a silicone rubber matrix to systematically engineer the conductive network architecture. By optimising the CB/MWCNT blending ratio, a composite with a tensile strength of 8.5 MPa, elongation at break of 180%, and EMI shielding effectiveness of 50 dB was achieved at a 1:1 weight ratio. Further surface modification of the hybrid fillers using five surfactants, including sodium dodecylbenzene sulfonate (SDBS), cetyltrimethylammonium bromide (CTAB), polyvinylpyrrolidone (PVP), nonylphenol ethoxylate (NPEO), and octylphenol ethoxylate (OPEO), was systematically investigated. OPEO modification was proved the most effective, improving EMI shielding performance to 58 dB while enhancing tensile strength by 11.8% and elongation at break by 50%. These results demonstrate that rational filler hybridisation combined with targeted surfactant modification offers a practical and scalable route to high-performance flexible EMI shielding composites. Full article

Background/Objectives: Sleep-disordered breathing (SDB), including obstructive sleep apnea, is common in children and is associated with mouth breathing, snoring, and neurobehavioral disturbances. In pediatric orthodontic patients, oral habits and craniofacial imbalances may contribute to airway dysfunction, making orthodontic evaluation a potential setting for early identification of SDB. This study aimed to estimate the prevalence of SDB and to evaluate its associations with parent-reported behavioral symptom profiles in a cohort of pediatric orthodontic patients. Methods: A multicenter cross-sectional study was conducted in 186 children aged 7–13 years attending orthodontic clinics in Oradea and Târgu Mureș, Romania. Parents completed a structured questionnaire on oral habits, the 22-item Pediatric Sleep Questionnaire (PSQ), with SDB defined as 8 or more positive responses, and a parent-reported behavioral screening form assessing ADHD symptom subtypes, oppositional-defiant disorder (ODD), conduct disorder, and anxiety/depression. These behavioral outcomes were based on screening measures and were not intended as clinical psychiatric diagnoses. Associations were analyzed using chi-square or Fisher’s exact tests, and multivariable logistic regression analyses were performed adjusting for age, sex, and weight status. Results: Mouth breathing was reported in 61.8% of participants, snoring in 26.9%, and SDB in 13.4%. Positive screens for ADHD-inattentive (p < 0.001), ADHD-hyperactive/impulsive (p < 0.001), ADHD-combined (p < 0.001), ODD (p < 0.001), and anxiety/depression (p < 0.001) were significantly more frequent among children with SDB. In multivariable analysis, SDB remained independently associated with ADHD-combined subtype (OR = 6.22), ADHD-hyperactive/impulsive symptoms (OR = 5.84), oppositional-defiant disorder (OR = 4.91), and anxiety/depression (OR = 4.38). Conclusions: SDB was identified in a meaningful proportion of pediatric orthodontic patients and was significantly associated with multiple screening-defined behavioral symptom domains. These findings support consideration of brief airway- and sleep-oriented screening during orthodontic assessment, particularly in school-aged children presenting with mouth breathing, snoring, or behavioral concerns. Given the cross-sectional and questionnaire-based design, the findings should be interpreted as associative and warrant confirmation in prospective studies using objective sleep measures. Full article

Traditional satellite-derived bathymetry (SDB) often suffers from systematic optical path distortions due to the neglect of seafloor slope effects, leading to significant accuracy degradation in high-gradient coastal areas. This study proposes a Slope-Aware Physics-Informed Neural Network (SA-PINN) framework that synergistically utilizes ICESat-2 bathymetric photons and Sentinel-2 multispectral imagery. The core innovation involves a slope-aware operator, integrated into the radiative transfer-based physics loss function, which explicitly rectifies directional optical path deviations induced by seafloor inclination. By fusing physical mechanisms with data-driven features, the model utilizes a seven-dimensional feature space comprising four spectral bands, two directional slope components, and prior depth. Applications at Culebra, Maui, and Molokai demonstrate that SA-PINN significantly outperforms the Stumpf model, Random Forest, and standard CNNs, achieving root mean square errors (RMSE) of 1.36 m, 2.91 m, and 1.34 m, respectively. Ablation studies confirm that SA-PINN reduces RMSE by up to 37% compared to CNN in complex regions with slopes exceeding 10°, ensuring superior physical consistency and spatial continuity. This research provides a robust, in situ-free automated solution for high-resolution bathymetric mapping in remote and steep coastal environments globally. Full article

Satellite-derived bathymetry (SDB) offers a practical alternative for mapping shallow reefs in remote oceanic settings where acoustic surveys are costly and logistically constrained. Here we benchmark PlanetScope 8-band (3 m) surface reflectance—an underused commercial constellation for reef SDB—using ICESat-2 Advanced Topographic Laser Altimeter System (ATLAS) ATL03 photon data (Release 006) as independent vertical control. Seventeen ATL03 ground tracks (2019–2025) were processed using geometric filtering, photon classification, and explicit air–water refraction correction. This yielded 5171 candidate seafloor observations, of which 5021 were co-located with valid PlanetScope water pixels after Usable Data Mask screening (UDM2/UDM2.1), sun-glint correction, and reflectance quality screening. Four SDB formulations (Lyzenga, Bierwirth, and Stumpf) were calibrated and independently validated using depth-stratified train/validation partitions (70/30, 80/20, and 90/10). Across partitions, the multiband polynomial model of Lyzenga 2006 generalized best (R² = 0.843–0.859; RMSE = 1.734–1.813 m; bias = −0.070 to −0.081 m), followed by Bierwirth (R² = 0.826–0.845; RMSE = 1.818–1.904 m). Lyzenga 1985 reported lower skill (RMSE ≈ 3.1 m), while the Stumpf log-ratio failed in independent validation. ICESat-2 photon bathymetry provides repeatable point-based control in clear waters but remains less precise than echo sounding due to photon classification and spatial-support effects; therefore, uncertainties and applicability limits must be reported. Overall, PlanetScope 3 m, 8-band surface reflectance supports reproducible reef-scale SDB in Seaflower under the evaluated conditions, with Lyzenga 2006 as a robust baseline. Full article

(1) Background: Early treatment of sleep-disordered breathing (SDB) with adaptive servo-ventilation (ASV) after acute myocardial infarction (AMI) has been shown to improve myocardial salvage. This analysis evaluates nocturnal electrocardiogram (ECG) Holter data, derived from polygraphy in a randomised clinical trial (NCT02093377), to assess the occurrence of nocturnal cardiac arrhythmias in patients with SDB and to explore the effect of ASV therapy. (2) Methods: In the TEAM-ASV I trial, patients were stratified by the presence/absence of SDB, defined by an apnoea–hypopnoea index (AHI) ≥15 events/h assessed with polygraphy. Those with SDB were subsequently randomised to receive ASV in addition to standard AMI care. Guideline-conforming semi-automated ECG analysis of nocturnal cardiac arrhythmias was conducted via Holter–ECG software (custo diagnostic, version 5.4). (3) Results: Patients with SDB had an increased incidence of non-sustained ventricular tachycardia (NSVT) (SDB: n = 8 (16%) vs. no SDB: n = 1 (2%); p = 0.024) and premature atrial contractions (PAC) (SDB: 1.2/h [0.3, 3.4] vs. no SDB: 0.3/h [0.1, 1.2]; p = 0.017). In patients with SDB who were randomised to ASV treatment early after AMI, we found no reduction in cardiac arrhythmias when ASV was added to standard care. (4) Conclusions: After AMI, SDB was linked to increased NSVT and PAC. ASV treatment demonstrated neither a harmful nor a beneficial effect on the occurrence of nocturnal cardiac arrhythmias. Further trials are warranted to confirm these findings. Full article

Dual-fuel combustion is often proposed for diesel engines as a means to partially replace conventional diesel with cleaner and/or more sustainable alternatives, such as those derived from green hydrogen. However, the low reactivity of these fuels (i.e., methane, hydrogen, and ammonia) often leads to prolonged ignition delay (ID) and combustion instability. This challenge could potentially be overcome using nanomaterials, which are additives that could improve reactivity and compensate for autoignition deficiencies. Thus, this study evaluates the effect of carbon nanotubes (CNTs) dispersed in diesel fuel on the autoignition process under dual-fuel operation. CNTs were dispersed at a concentration of 100 mg/L and stabilized with surfactant sodium dodecylbenzene sulfonate (SDBS). The resulting nanofuels were then tested in a constant volume combustion chamber (CVCC) using methane, hydrogen, and ammonia as secondary fuels across various energy substitution ratios and temperatures (535 °C, 590 °C and 650 °C). The results show that the impact of CNTs on ID is negligible, especially at high temperatures. At the lowest tested temperature (535 °C) and 40% methane substitution ratio, only slight reductions in ID were obtained. Nevertheless, this effect is less significant at higher temperatures (590 °C and 650 °C). Regarding pressure gradient, the addition of CNTs and SDBS generally induced a decrease in pressure-peak of up to 15%. This trend is attributed to the trapping of fuel droplets within the CNT structures, which creates a physical barrier that delays vaporization. Results confirm that autoignition, which is expected to be the main phenomenon influenced by CNT addition, is not enhanced. Full article

Background: Vulvovaginal candidiasis (VVC) is a significant public health concern characterized by increasing incidence and challenges in treatment. However, most studies investigating Candida spp. virulence factors and antifungal susceptibility predominantly rely on in vitro assays. While these assays are highly reproducible, they do not accurately replicate the complex vaginal microenvironment. To address this limitation, we developed an ex vivo model using porcine vaginal mucosa and a physiologically relevant volume of simulated vaginal fluid (SFV) to better mimic human vaginal conditions. Methods: Biofilm formation and fluconazole activity were assessed using the reference strain Candida albicans ATCC 90028 and two clinical isolates associated with VVC. Results were expressed as colony-forming units (CFU) and directly compared with in vitro assays conducted in Sabouraud dextrose broth (SDB) and SVF. Results: CFU analysis revealed that the ex vivo vaginal mucosa model supported more robust biofilm development, with counts ranging from 6.67 × 10⁷ to 7.20 × 10⁷ CFU/mL, compared to the in vitro SDB assay (3.58 × 10⁷ to 4.5 × 10⁷ CFU/mL). This suggests enhanced fungal growth under tissue-based conditions. Moreover, fluconazole achieved greater biofilm eradication in the ex vivo model (>70%) compared to the in vitro SDB assay (≤34.50%), which may indicate increased antifungal activity within a physiologically relevant environment. Conclusions: The ex vivo vaginal mucosa model offers a physiologically relevant platform for supporting C. albicans biofilm development and serves as a valuable alternative for preclinical screening of antifungal agents. Full article

Background/Objectives: Pediatric sleep-disordered breathing (SDB) is influenced by craniofacial morphology and host susceptibility. Evidence integrating cephalometric airway features with targeted genetic variation in symptomatic skeletal Class II children remains limited. We explored whether children with skeletal Class II mandibular retrognathia and SDB symptoms harbor selected genetic variants and whether carriers show distinct cephalometric airway characteristics. Methods: This cross-sectional study included 48 children with skeletal Class II malocclusion, mandibular retrognathia, and snoring/mouth-breathing symptoms. Craniofacial and airway parameters were assessed on lateral cephalograms. SDB burden was evaluated by a baseline home sleep study (respiratory event index, REI). Targeted sequencing screened TNFRSF1A, PSTPIP1, SLC6A4 (5HTT), ACE, APOE, IRS1, and additionally PHOX2B and PMP22. Exploratory group comparisons used Student’s t-test. Results: Variants were identified in 13/48 participants (27%) in TNFRSF1A, PSTPIP1, SLC6A4, ACE, APOE, and IRS1; none were detected in PHOX2B or PMP22. C3–H was higher in variant carriers (39.90 ± 6.40 vs. 36.48 ± 3.95 mm; p < 0.05). HH1 (perpendicular distance from the hyoid bone to the C3–RGN line) was higher but not significant (16.99 ± 7.58 vs. 14.61 ± 5.25 mm; p > 0.05). Conclusions: In this clinically screened pediatric skeletal Class II cohort with SDB symptoms, selected genetic variants co-occurred with specific hyoid–cervical cephalometric features. Given the cross-sectional design, absence of a control group, and small number of carriers, findings are exploratory and require replication in larger, controlled cohorts with standardized phenotyping. Full article

Satellite-derived bathymetry holds significant value for acquiring nearshore bathymetric data. However, in coastal waters, bathymetry is affected by in-water particle scattering and seafloor substrate variability, leading to spatial inconsistency between the logarithmic green band profile derived from multispectral satellite imagery and the actual water depth profile. According to the position information of interpolated points and the inverse distance square relationship with the surrounding 16 points from low-reference bathymetric data (such as the bathymetric map from GEBCO, NOAA Electronic Navigational Charts), this model adopts a third-order inverse distance square bicubic convolution interpolation method to resample a high-resolution bathymetric map with the size of the satellite image. Normalized underwater topography trend data (derived from the low-resolution reference bathymetric map) were combined with normalized green band data to compute an averaged dataset. In this way, a linear bathymetric model was constructed. We invert this model’s parameters and calculate the water depth by using the average data and reference points from reference bathymetric data. Validation tests were conducted across three test areas using independent validation bathymetric data: Weizhou Island, China (Case II waters); Saipan, Northern Mariana Islands, USA (Case I waters); and Molokai Island, Hawaii, USA (Case I waters). Each test area was studied using five error analysis methods (i.e., scatterplot, error histogram, regional bathymetric error, three check lines, and seven check points). Compared to four classic bathymetric models (i.e., single-band model, log-ratio model, ratio-log model, and multi-band model), the proposed model achieved lower root mean square errors (RMSE) of 2.08 m, 1.40 m, and 2.01 m in the three test areas, representing reductions of 35%, 43%, 45%, and 20% and overall averages of 48%, 62%, 64%, and 43%, respectively. Its goodness of fit (R²) reached 0.87, 0.97, and 0.97, showing improvements of at least 5%, 5%, 9%, and 9% and overall averages of 17%, 77%, 84%, and 12%, respectively. The results demonstrate that the proposed model significantly improves bathymetry accuracy while maintaining algorithmic simplicity, providing a new model for acquiring nearshore foundational bathymetric maps. Full article

Background: Childhood obesity is a growing public health concern globally and is associated with a wide spectrum of comorbidities, including sleep-disordered breathing (SDB). SDB remains under-recognized in pediatric population with obesity, particularly in Middle Eastern settings, despite its significant impact on cognitive, behavioral, and metabolic health. Objectives: To assess the prevalence of SDB among children with obesity aged 6–12 years attending King Faisal University polyclinics in Saudi Arabia and to identify key demographic and anthropometric predictors, with particular emphasis on the mediating role of neck circumference. Methods: A cross-sectional study was conducted involving 130 children with obesity aged 6–12 years. Data collection included sociodemographic characteristics, anthropometric measurements (BMI percentile, neck and waist circumference), and screening for SDB using the validated Arabic version of the Pediatric Sleep Questionnaire Sleep-Related Breathing Disorder (PSQ-SRBD) scale. Logistic regression and mediation analyses were performed to examine associations and pathways between obesity parameters and SDB risk. Results: Of the 130 participants, 37.7% screened positive for SDB risk. SDB prevalence was higher among males and older children. Neck circumference and BMI percentile were independently associated with SDB risk, with neck circumference mediating the relationship between BMI and SDB. The mediation model indicated that increased BMI contributes to SDB risk both directly and indirectly through increased neck circumference. Conclusions: SDB is highly prevalent among obese Saudi children, and neck circumference is a significant mediator of risk. Incorporating SDB screening and neck circumference measurements into routine pediatric obesity care can facilitate early detection and management. These findings support the need for integrated, multidisciplinary approaches to improve pediatric health outcomes. Full article

Background: Community-acquired pneumonia (CAP) in children may be complicated by necrotizing pneumonia (NP), complicated parapneumonic effusion (CPPE), and lung abscess. These complications prolong hospitalization and require medical and surgical intervention. Objectives. To describe clinical course, diagnostic workup, and management of cCAP (complicated CAP) in children admitted to the Women’s and Children’s Health Department, Padua University Hospital, between January 2022 and September 2024. To identify factors associated with disease severity and evaluate outcomes. Methods: All children hospitalized for cCAP during the study period were included. Data collected comprised clinical features, laboratory and imaging findings, medical and surgical management, and outcomes. Results: Forty patients (mean age 4.4 y; 13.15% of pneumonia admission) were included: 67.5% had NP with CPPE, 22.5% isolated effusion, 10% NP without effusion. All patients were febrile at onset, 62.2% had cough, 32.5% abdominal pain, 30% rhinitis. NP was confirmed by contrast-enhanced chest CT. Thirty patients (75%) had positive microbiological testing, mainly Streptococcus pneumoniae and Streptococcus pyogenes. 77.5% required oxygen therapy (five invasive ventilation and one with ECMO). Median fever duration 18 days (IQR 15–27) with elevated CRP (median peak 300 mg/L). Pleural drainage was performed in 66.7%, fibrinolytics in 17.5%, thoracoscopic decortication in 12.5%, and lobectomy in one patient. Radiological resolution occurred at a median of 31 days post-discharge, with normal pulmonary function at a median of 15 months. Conclusions: Despite pediatric cCAP severity, short- and long-term outcomes are favorable. Early recognition and integrated management are crucial, and further prospective studies are warranted to optimize care and identify severity predictors. Full article

Sleep-disordered breathing (SDB) is common after stroke and may negatively influence recovery, yet it is frequently underdiagnosed. Portable respiratory monitoring devices could facilitate early SDB screening in these patients. We estimated the prevalence of sleep apnea (SA) using a smartphone-based monitoring system in post-stroke patients and examined associations between respiratory indices, stroke severity and disability (NIHSS, mRS), and rehabilitation outcomes (motor and cognitive Functional Independence Measure; FIM). Consecutive patients admitted to inpatient rehabilitation within three months after a stroke underwent an overnight assessment with a smartphone-based respiratory monitoring device, which estimated the apnea–hypopnea index (AHI), mean and minimum SpO₂, time with SpO₂ < 94% and <90%, and hourly oxygen desaturation events (≥3% and ≥4%). Of the 104 screened patients, 59 were recruited, while 56 had valid recordings. Most patients (89%) had previously undiagnosed SA: 11% mild (AHI ≥ 5 and <15), 38% moderate (AHI ≥ 15 and <30), and 41% severe (AHI ≥ 30). Greater event burden and nocturnal hypoxemia were associated with older age, worse baseline disability (mRS), lower admission motor FIMs, and poorer rehabilitation metrics. Smartphone-based portable monitoring is an accessible, easy-to-use approach that may enable earlier identification of SA, particularly in individuals with substantial hypoxemia or respiratory event burden. Full article