Search Results (8,308)

Driven by factors such as meteorology, topography, and industrial structure, the concentrations of volatile organic compounds (VOCs) exhibit significant spatial heterogeneity. Investigating the characteristics and sources of VOCs in different regions is therefore crucial for formulating targeted strategies to mitigate their contributions to fine particulate matter (PM_2.5) and ozone (O₃) pollution. This study comprehensively investigated—for the first time—the concentration characteristics, sources, and contributions to secondary organic aerosol (SOA) and O₃ formation of VOCs at an urban background site in Ganzhou, a southern Chinese city, based on hourly observations of VOCs during 2023. Analyses included ozone formation potential (OFP), secondary organic aerosol formation potential (SOAFP), and positive matrix factorization (PMF) source apportionment. The influence of photochemical loss was assessed using a photochemical age parameterization method. The results showed an annual average total VOC concentration of 22.6 ± 13.17 ppbv, with higher levels in winter and lower in summer. Alkanes were the dominant species (45.76%). After correcting for photochemical loss, the initial concentration of VOCs (IC-VOCs) was approximately 60% higher than the observed concentration of VOCs (OC-VOCs), with alkenes becoming the dominant group in IC-VOCs (≈72%). OFP analysis indicated that the OFP calculated using initial VOC concentrations (IC-OFP) was substantially higher (by 320 μg/m³) than the values calculated using observed VOC concentrations (OC-OFP), primarily due to the increased contribution of alkenes. SOAFP was higher in spring and winter, and lower in summer and autumn, with aromatic hydrocarbons being the dominant contributors (>85%). PMF results based on month-case studies identified combustion and industrial process sources as the major contributors (>20%) in August, while combustion and vehicle exhaust dominated in January. Photochemical loss significantly influenced source apportionment, particularly leading to an underestimation of biogenic emissions during a warm month (August). These findings underscore the necessity of accounting for photochemical aging and offer a scientific basis for refining targeted VOC control measures in Ganzhou and similar regions. Full article

The aim of this study is to investigate the impact of layered nanomodifiers with distinct chemical structure and morphology, namely graphene nanoplates (GnP) and sodium montmorillonite (Na-MMT), on thermal degradation of polylactic acid (PLA). The exploration was performed with thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and pyrolytic gas chromatography–mass spectrometry (PyGCMS). The findings revealed a catalytic effect of Na-MMT on PLA thermal destabilization, manifested in accelerated degradation and the notable change in the composition of pyrolysis products. In contrast, the incorporation of graphene nanoplates into the PLA matrix induced a “barrier effect”: it imposed diffusion limitations on the emission of volatile degradation products during pyrolysis, which enhanced the thermal stability of the PLA/GnP composite and led to quantitative alterations in the distribution of major pyrolysis products. To elucidate the underlying degradation pathways, authors proposed a model kinetic analysis of thermal degradation for both PLA/GnP and PLA/Na-MMT composites. The analysis clearly distinguished the mechanistic differences between the two systems: while Na-MMT promotes catalytic decomposition, GnP primarily acts as the physical barrier retarding mass transport and delaying the thermal degradation development. Good alignment of theoretical model–kinetic predictions with Pyrolysis–GC/MS observations confirms the robustness of the suggested kinetic modeling method. Full article

Cardiovascular diseases remain the leading cause of mortality worldwide, underscoring the urgent need for reliable in vitro models that recapitulate the complexity of the native myocardium. Conventional two-dimensional (2D) cultures lack structural and biochemical complexity, whereas in vivo models are costly, raise ethical concerns, and have poor translational potential. In this study, we developed a novel hydrogel scaffold derived from decellularized porcine ventricular myocardium (dECM). A newly optimized decellularization strategy effectively removed cellular and nuclear components while preserving essential extracellular matrix proteins. The dECM-based hydrogel exhibited reproducible self-crosslinking, gelation kinetics, and stability. Cytocompatibility assays using human bone marrow-derived mesenchymal stem cells demonstrated excellent viability and proliferation upon contact with the biomaterial. Multidimensional hydrogel applications (2.5D and 3D) in vitro revealed higher cell densities than those observed under 2D conditions. Moreover, using human umbilical vein endothelial cells, the dECM-based hydrogel proved to be a valid tool for fabricating cardiovascular in vitro models. As such, this cardiac dECM-based hydrogel is a structurally preserved, biocompatible platform that supports both short- and long-term cell culture. The scaffold has the potential to serve promising applications in cardiac tissue engineering, disease modeling, and cardiotoxicity screening by offering a closer mimicry of the native myocardial environment. Full article

Silicone-based implants have been widely used in breast reconstruction but have also been associated with poorly understood complications, including pathologic foreign body responses such as capsular contracture. In this study, we leveraged 3D-printing technology to generate silicone-based implants in a novel, anatomically relevant, prepectoral rat model. We used this model to evaluate the response to an extracellular matrix-based product: ovine-derived reinforced tissue matrix (RTM). Two-piece negative molds were developed through computer-aided design and 3D-printed. The molds were filled with various polydimethylsiloxane mixtures and dip-coated to fabricate implants. Implant material characterization revealed that the implants retained the original 3D-printed mold shape and qualitatively demonstrated a shell with an inner solid gel-like structure. Fabricated implants had smooth surfaces, as well as tunable features including implant stiffness (storage modulus). From initial studies in our rat model, placement of bilateral prepectoral implants allowed assessment of both muscle- and skin-facing capsules and were well-tolerated for at least 12 weeks. Comparison of the foreign body response between RTM-covered and uncovered (control) implants in this model revealed that the capsule thickness did not differ between groups at the 12-week endpoint. However, RTM reduced contractile fibroblasts (alpha-smooth muscle actin) and macrophages (Iba1) compared to the control. Our findings suggested that RTM may improve capsule quality by attenuating cells involved in fibrosis, even when total capsule thickness remains unchanged. However, these changes to cells involved in fibrosis were only observed at this early endpoint and may not predict long-term clinical outcomes. Full article

Postoperative facial scars frequently remain aesthetically problematic despite advances in laser-based treatments, as residual inflammation and disorganized dermal remodeling often limit clinical outcomes. Exosome-based formulations have gained attention as biologically active adjuncts capable of influencing key wound-healing pathways, including inflammatory regulation, neovascularization, and extracellular matrix modulation. This randomized, controlled clinical study aimed to evaluate the short-term clinical effect of laser-assisted delivery of exosome skin boosters for postoperative facial scars and facial rejuvenation. Seventy-five patients with postoperative facial scars were randomly allocated to receive fractional non-ablative Nd:YAG laser treatment alone or in combination with either human-derived or plant-derived exosome skin boosters. All participants completed five treatment sessions at two-week intervals. Clinical outcomes were evaluated using validated scar assessment tools, including the modified Vancouver Scar Scale and the Patient and Observer Scar Assessment Scale, along with objective imaging analyses using Mark-Vu and ImageJ software. Compared with laser monotherapy, adjunctive exosome treatment was associated with numerically greater short-term improvements in scar appearance and reductions in grayscale intensity. Improvements in additional skin quality parameters, such as pigmentation uniformity, erythema, pore size, and fine wrinkles, were also observed in the exosome-treated groups. Clinical responses were comparable between human- and plant-derived exosome formulations, and no serious adverse events were reported. These findings indicate that exosome-based skin boosters may serve as a safe and well-tolerated biological complement to laser therapy for short-term improvement of postoperative facial scars and skin quality. Larger studies with longer follow-up are warranted to determine long-term efficacy and clinical durability. Full article

In this work, we develop a disturbance suppression-oriented fuzzy sliding mode secured sampled-data controller for third-order parabolic partial differential equations that ought to cope with nonlinearities, hybrid cyber attacks, and modeled disturbances. This endeavor is mainly driven by formulating an observer model with a T–S fuzzy mode of execution that retrieves the latent state variables of the perceived system. Progressing onward, the disturbance observers are formulated to estimate the modeled disturbances emerging from the exogenous systems. In due course, the information received from the system and disturbance estimators, coupled with the sliding surface, is compiled to fabricate the developed controller. Furthermore, in the realm of security, hybrid cyber attacks are scrutinized through the use of stochastic variables that abide by the Bernoulli distributed white sequence, which combat their unpredictability. Proceeding further in this framework, a set of linear matrix inequality conditions is established that relies on the Lyapunov stability theory. Precisely, the refined looped Lyapunov–Krasovskii functional paradigm, which reflects in the sampling period that is intricately split into non-uniform intervals by leveraging a fractional-order parameter, is deployed. In line with this pursuit, a strictly $({\Phi }_1,{\Phi }_2,{\Phi }_3)-\varrho$ dissipative framework is crafted with the intent to curb norm-bounded disturbances. A simulation-backed numerical example is unveiled in the closing segment to underscore the potency and efficacy of the developed control design technique. Full article

In this study, films based on polysaccharides with C. sativa flower extract were prepared for selected freeze-dried fruits: raspberry (Rubus idaeus L.) and blueberry (Vaccinium corymbosum L.). The extract used affected the barrier and mechanical properties of the film. The elongation values of the film ranged from 32.5 ± 8.6 [%] (for sample 0) to 44.8 ± 8.2 [%] (for sample 4.0 F). The addition of the extract resulted in an increase in polyphenol content, proportional to the quantity of extract used. Spearman’s rank correlation analysis showed particularly strong correlations between colour indices (L*, a*, b*) and parameters describing antioxidant activity. The use of C. sativa flower extract in the polysaccharide matrix reduced the degradation of bioactive compounds during the storage of packaged fruit. In all cases of stored raspberries, a decrease in the number of moulds and yeasts was observed after 2 and 8 weeks. The greatest reduction in moulds and yeasts was recorded for the 4.0 F film (from 0.86 to 0.64 log cfu/g). In the case of blueberries, the total number of bacteria before storage was 2.52 log cfu/g, while after 8 weeks of storage in 4.0 F, this number significantly decreased to 2.28 log cfu/g. As in the case of raspberries, a reduction in mould and yeast was observed, with concentrations falling from an initial value of 0.89 to 0.67 log cfu/g after 8 weeks of storage at 4.0 F. Full article

In this study, an electrochemical valorization strategy on liquid byproducts from hazelnut shell gasification was developed to couple waste remediation with energy-efficient hydrogen production. The aqueous phase, rich in organic compounds, is processed in an anion exchange membrane (AEM) cell, where pure hydrogen evolved at the cathode while organic pollutants are oxidized at the anode. First, the feedstock is thoroughly characterized using gas chromatography–mass spectrometry (GC-MS), identifying a complex matrix of water-soluble aromatic compounds such as phenols, catechols, and other aromatics compounds, with concentrations reaching up to 2.9 g/kg for catechols. Then, the electro-reforming process is optimized using Nickel oxide–hydroxide (Ni(O)OH) electrodes with a loading of 0.75 mg/cm². This methodology relies on the favorable thermodynamics of organic oxidation, which requires a lower onset potential (0.4 V) compared to the oxygen evolution reaction (OER) observed in the alkaline control (0.52 V), and the low overpotential of the Nickel oxide–hydroxide electrode towards the oxidized species. Consequently, the organic load undergoes progressive oxidation into hydrophilic and less bioaccumulating species and carbon dioxide, allowing for the simultaneous generation of pure hydrogen at the cathode at a reduced cell voltage. Elevated stability was observed, with a substantial abatement—78% of the initial organic load—of organic compounds achieved over 80 h at a fixed cell voltage of 0.5 V, and a specific energy consumption for hydrogen production of $38.5 \mathrm{M}\mathrm{J}\cdot {\mathrm{k}\mathrm{g}}_{{\mathrm{H}}_2}^{-1}$. This represents a step forward in the development of technologies that reduce the energy intensity of hydrogen generation while valorizing biomass gasification residues. Full article

Substitutional elements are introduced to face-centered cubic (FCC) multi-principal element alloys (MPEAs) to effectively enhance the mechanical performance by solid solution strengthening and second-phase strengthening. Commonly, relatively large atomic radius elements introduced into the alloy matrix result in lattice distortion and hinder grain boundary migration, thus achieving matrix strengthening. However, owing to the complex compositions of MPEAs, different substitutional elements introduced affect the microstructure evolution behavior and corresponding strengthening effects. In this work, an abnormal grain growth behavior of Ni-Co-Cr-based MPEAs based on Al alloying was observed. Systematic annealing experiments combined with quantitative grain growth analysis were conducted to clarify the effects of Al, W, and Mo on grain boundary migration. The results show that substitutional Al reduces the apparent activation energy for grain growth, resulting in both a lower grain growth component (n = 2) and a lower activation energy for grain growth of 219 kJ/mol, thereby enhancing grain boundary mobility. On the contrary, minor additions of high-melting-point W and Mo effectively inhibited the Al-induced rapid grain growth by increasing the activation energy and resulting in a higher grain growth component and a lower activation energy for grain growth of 251 kJ/mol. These findings provide new insights into the role of substitutional solutes in controlling grain growth kinetics in multi-principal element alloys. Full article

Targeted synthesis of Ni/C-containing composite materials was carried out using the matrix isolation method. The Ni content was varied (5–20 wt.% from chitosan). The morphology and physicochemical properties of the obtained materials were characterized using a number of methods: elemental analysis, SEM, TEM, XRD, FTIR, Raman spectroscopy, TPR–H₂, and SSA. FTIR showed that nickel ions are immobilized on the chitosan molecule, and heat treatment of the polymer molecule results in the formation of polyconjugation centers. It was also revealed that heat treatment of the salt–polymer films results in the formation of a graphite-like structure (Raman spectroscopy) with the inclusion of nickel in metallic form (XRD, TPR–H₂), with a particle size from 2 to 10 nm (TEM). The composites were shown to have a SSA of up to 269 m²/g. The resulting composite materials were used as catalysts for the decomposition of methane to produce hydrogen. High activity was observed in the catalytic methane decomposition at 700 °C (methane conversion up to 25.8%; hydrogen yield up to 1.98 g_H2/g_Ni/h). Full article

This work investigates the synthesis, thermodynamic phase stability and microstructural, mechanical and tribological behavior of the CrFeMoV alloy system and its Al-modified derivatives, CrFeMoV-Al2 and CrFeMoV-Al6, which belong to the family of high- and medium-entropy alloys. The studied systems were produced via Vacuum Arc Melting (VAM), followed by a comprehensive characterization. Thermodynamic and geometric phase-formation models were employed to predict the formation of BCC/Β2 solid solutions and the potential emergence of σ-type intermetallic compounds. An ML model was also employed to further predict elemental interactions and phase evolution. These predictions were experimentally confirmed via X-ray diffraction analysis, which verified the presence of a BCC matrix in all compositions, the presence of σ-phase precipitates whose volume fraction systematically reduced with Al inclusion and the gradual increase in the B2 phase with the increase in the Al content. Scanning electron microscopy and EDX analyses uncovered noticeable dendritic segregation, with Mo and Fe enrichment in dendrite cores and in interdendritic regions, respectively. Cr, V, and Al were more uniformly distributed. Mechanical property data derived by micro hardness testing demonstrated a high hardness of 816 HV for the base alloy, ascribed to σ-phase strengthening, followed by a progressive reduction in this value to 802 HV and 756 HV in Al-containing alloys due to the attenuation of σ-phase formation and the gradual increase in the B2 phase. Dry sliding wear results unveiled a positive correlation between wear resistance and hardness, confirming the beneficial role of intermetallic strengthening. Finally, nanoindentation tests shed light on the nanoscale mechanical response, confirming the trends observed at the microscale. Overall, the combination of thermodynamic modeling and experimental analysis provide a robust framework for understanding phase stability, microstructural evolution, and mechanical performance in Al-alloyed CrFeMoV high-entropy systems, while highlighting the potential of controlled Al additions to tailor microstructure and properties. Full article

Hemostatic biomaterials are widely used in surgical and trauma settings, yet their influence on early wound healing remains incompletely understood. This in vivo study investigated the effects of cellulose- and gelatin-based hemostatic biomaterials on early wound healing using a murine skin wound model. Oxidized non-regenerated cellulose (ONRC), oxidized regenerated cellulose (ORC), and a porcine gelatin-based matrix (GELA) were left in situ following standardized subcutaneous implantation and compared with sham-treated controls. Tissue responses were analyzed at postoperative days 3 and 7 using histology, immunohistochemistry, and quantitative real-time polymerase chain reaction (qPCR). Cellulose-based materials persisted as eosinophilic remnants, whereas fibrous matrix structures and enhanced extracellular matrix deposition were observed in the GELA group. Immunohistochemical analysis revealed increased cluster of differentiation 68 (CD68)–positive macrophage presence in the ORC group at day 3 and in the GELA group at day 7, indicating biomaterial-dependent modulation of macrophage involvement during early wound healing. Expression of Kiel 67 (Ki-67), a marker of cellular proliferation, was significantly elevated in the epidermis of the GELA group at day 7, suggesting enhanced proliferative activity during the reparative phase. In contrast, no significant differences were detected in the expression of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), or cluster of differentiation 14 (CD14) between groups. Overall, none of the investigated biomaterials impaired early wound healing, while the gelatin-based material demonstrated features consistent with enhanced reparative cellular responses without excessive inflammation. Full article

Open-hole compression (OHC) tests were carried out on non-crimp fabric (NCF) laminates with varied open-hole orientation (angle to the loading direction) and inter-hole spacing. Failure modes were documented by scanning electron microscopy (SEM), and the compressive strength was quantified. Finite element simulations in Abaqus were developed to replicate the tests, establishing a progressive-damage model for open-hole laminates under compression. Intralaminar failure was described using the three-dimensional Hashin failure criterion and a modified matrix compression criterion incorporating shear coupling effects, while interlaminar delamination was modeled with cohesive elements, enabling the simulation of damage initiation, growth, delamination, and final collapse. The results show that hole orientation and spacing have a pronounced effect on open-hole compression (OHC) strength. A spacing threshold is observed, beyond which further increases in spacing provide little additional benefit. In contrast, the apparent elastic stiffness is essentially insensitive to hole spacing and orientation. The combined intralaminar and interlaminar model successfully reproduces the characteristic mechanical response—linear elasticity followed by catastrophic failure—in good agreement with the experiments. Full article

Aging alters cardiac resilience to anesthetic and surgical stress, yet the molecular basis for these effects remain poorly understood. To define age-dependent transcriptional responses, we profiled cardiac gene expression across young adult (3 m), late middle-aged (17 m), and old mice (27 m) following 2 h isoflurane and operative (Iso/Op) exposure. Across all age groups, 24 h after cessation, Iso/Op induced distinct transcriptional signatures relative to the sham, with conserved perturbations in oxidative stress responses, Ca²⁺ handling, hypertrophy-associated signaling, and energy metabolism. In 3 m hearts, transcriptional alterations were characterized by dysregulation of small-molecule catabolism, fatty acid metabolism, endoplasmic reticulum processing, and cytoskeletal organization. In 17 m hearts, lipid metabolic disruption was amplified and accompanied by suppression of muscle system and calcium signaling pathways. In 27 m hearts, Iso/Op robustly activated PPAR and AMPK signaling and fatty acid catabolic programs while downregulating pathways governing contractility, actin organization, and morphogenesis, consistent with age-associated maladaptive metabolic reprogramming. To assess persistence, we analyzed a longitudinal cohort of 20 m mice five weeks after exposure and observed sustained transcriptomic remodeling driven predominantly by isoflurane, including mitochondrial dysfunction and altered expression of genes linked to diabetic cardiomyopathy, extracellular matrix integrity, and neurodegeneration-associated pathways. Together, these data suggest that isoflurane-based perioperative stress can produce age-amplified and durable metabolic and structural cardiac remodeling, implicating impaired lipid utilization and mitochondrial homeostasis as potential mechanisms of long-term cardiovascular vulnerability. Full article

The pygmy hippopotamus (Choeropsis liberiensis, Morton, 1849) is classified as Endangered by the International Union for the Conservation of Nature (IUCN). Compared to other large, threatened mammals, this species remains relatively understudied and new findings indicate potential welfare concerns, emphasizing the need for further research on the species welfare in zoological institutions. One approach to improving welfare in captivity is through environmental enrichment. This study investigated the effects of olfactory enrichment on three individual pygmy hippopotamuses through behavioral analysis and heat-map visualization. Using continuous focal sampling, several behaviors were influenced by the stimuli, with results showing a general decrease in inactivity and an increase in environmental engagement and interaction, particularly through scenting behavior. To further enhance behavioral quantification, machine learning techniques were applied to video data, comparing manual and automated behavior classification using the pose estimation program SLEAP. Four behaviors Standing, Locomotion, Feeding/Foraging, and Lying Down were compared. A confusion matrix, time budgets, and Kendall’s Coefficient of Concordance (W) were used to assess agreement between methods. The results showed a strong and moderate agreement between manual and automated annotations, for the female and calf, respectively. This demonstrates the potential of automation to complement behavioral observations in future welfare monitoring. Full article