Search Results (416)

Chemical looping combustion (CLC), a promising technology employing oxygen carriers to realize cyclic oxygen transfer between reactors, represents a transformative approach to CO₂ capture with near-zero energy penalties. Among oxygen carriers, Fe-based materials have emerged as the predominant choice due to their cost-effectiveness, environmental compatibility, and robust performance. The reaction kinetics of oxygen carriers are crucial for both material development and the rational design of CLC systems. This comprehensive review synthesizes experimental and theoretical advances in kinetic characterization of Fe-based oxygen carriers, encompassing both natural and synthetic materials, while different models corresponding to specific reaction stages and their intrinsic relationships with microstructural transformations are systematically investigated. The kinetic characteristics across various reactor types and experimental conditions are analyzed. The differences between fixed bed thermogravimetric analysis and fluidized bed analysis are revealed, emphasizing the notable impacts of attrition on the kinetic parameters in fluidized beds. Furthermore, the effects of temperature and gas concentration on kinetic parameters are profoundly examined. Additionally, the significant performance variation of oxygen carriers due to their interaction with ash is highlighted, and the necessity of a quantitative analysis on the competing effects of ash is emphasized, providing actionable guidelines for advancing CLC technology using kinetics-informed material design and operational parameter optimization. Full article

The increasing global demand for clean water is driving the development of advanced wastewater treatment technologies. Graphitic carbon nitride (g-C₃N₄) has emerged as an efficient photocatalyst for degrading organic pollutants, such as synthetic dyes, due to its exceptional thermo-chemical stability. However, its application is limited by an insufficient specific surface area, low photocatalytic efficiency, and an unclear degradation mechanism. In this study, we aimed to enhance g-C₃N₄ by doping it with elemental chlorine, resulting in a series of Cl-C₃N₄ photocatalysts with varying doping ratios, prepared via thermal polymerization. The photocatalytic activity of g-C₃N₄ was assessed by measuring the degradation rate of RhB. A comprehensive characterization of the Cl-C₃N₄ composites was conducted using SEM, XRD, XPS, PL, DRS, BET, EPR, and electrochemical measurements. Our results indicated that the optimized 1:2 Cl-C₃N₄ photocatalyst exhibited exceptional performance, achieving 99.93% RhB removal within 80 min of irradiation. TOC mineralization reached 91.73% after 150 min, and 88.12% removal of antibiotics was maintained after four cycles, demonstrating the excellent stability of the 1:2 Cl-C₃N₄ photocatalyst. Mechanistic investigations revealed that superoxide radicals (·O₂⁻) and singlet oxygen (¹O₂) were the primary reactive oxygen species responsible for the degradation of RhB in the chlorine-doped g-C₃N₄ photocatalytic system. Full article

Acinetobacter baumannii (A. baumannii), a very common pathogen, poses a significant public health threat due to its antibiotic resistance and long survival in healthcare environments. Both A. baumannii and carbapenem-resistant A. baumannii (CRAB) can spread through the air, increasing infection risks. Therefore, monitoring their presence in the air is of great significance, especially in hospitals. Herein, we developed a Chelex-100-LAMP-CRISPR/Cas12a (CLC) platform including DNA release and nucleic acid test. Combined with a wet cyclone sampler, the platform can detect airborne A. baumannii and its most common carbapenem-resistant gene, bla_OXA-23, within 70 min. This CLC platform has also been proven to have a detection limit of 6 × 10² CFU of CRAB per test through simulated air samples. Moreover, this platform was also used to test five actual air samples from a tertiary hospital, and the results achieved perfect concordance with sequencing data, validating the platform’s accuracy and reliability. Therefore, the CLC platform showed great potential for the rapid, on-site detection of airborne A. baumannii and its carbapenem-resistant gene bla_OXA-23, offering a valuable tool for infection control in healthcare environments. Full article

Pore structure plays a critical role in evaluating shale “sweet spots”. Compared to marine shale, lacustrine shale has more diverse lithofacies types and greater heterogeneity in pore structure due to frequently changing environmental conditions. Using methods such as mercury intrusion porosimetry (MIP), field emission scanning electron microscopy (FE-SEM), nuclear magnetic resonance (NMR), and X-ray diffraction (XRD), this study investigates the micropore structures and heterogeneity of different lithofacies in the Jurassic Dongyuemiao Member lacustrine shale. Image processing and multifractal theory were employed to identify the controlling factors of pore structure heterogeneity. The key findings are as follows. (1) Based on mineral content and laminae types, the lithofacies types of Dongyuemiao lacustrine shale are classified into four types: shell–laminae mixed shale (SLMS), silty–laminae clay shale (SLCS), clast–laminae clay shale (CLCS), and clay shale (CS). (2) Based on genesis, shale reservoirs’ pore and permeability space are categorized into inorganic pores, organic pores, and micro-fractures. Inorganic pores consist of inter-particle pores and intra-particle pores. Pore size distribution curves for all four lithofacies exhibit two main peaks, with pore sizes concentrated in the ranges of 2–10 nm and 50–80 nm. Mesopores and macropores dominate, accounting for over 80% of the total pore volume. Mesopores are most developed in CLCS, representing 56.3%. (3) Quartz content is positively correlated with the multifractal dimension, while clay content shows a negative correlation. Higher quartz content, coupled with lower clay content, weakens pore structure heterogeneity. A negative correlation exists between total organic carbon (TOC) and the multifractal dimension, indicating that higher organic matter content enhances organic pore development and increases microscopic heterogeneity. (4) Porosity heterogeneity in SLMS is effectively characterized by D₀-D_max, while in the other three lithofacies, it is characterized by D_min-D₀. Permeability across all lithofacies correlates with D₀-D_max. In CS, SLMS, and SLCS, permeability is positively correlated with D₀-D_max, with higher values indicating greater permeability heterogeneity. In CLCS, permeability is negatively correlated with D₀-D_max, such that lower values reflect stronger heterogeneity. Full article

Mammalian spermatozoa undergo a series of physiological and biochemical changes in the oviduct that lead them to acquire the ability to fertilize eggs. During their transit in the oviduct, spermatozoa face a series of environmental changes that can affect sperm viability. A series of ion channels and transporters, as well as the sperm cytoskeleton, allow spermatozoa to remain viable and functional. Cl⁻ channels such as TMEM16A (calcium-activated chloride channel), CFTR (cystic fibrosis transmembrane conductance regulator), and ClC3 (chloride voltage-gated channel 3) are some of the ion transporters involved in maintaining cellular homeostasis. They are expressed in mammalian spermatozoa and are associated with capacitation, acrosomal reaction, and motility. However, little is known about their role in maintaining sperm volume. Therefore, this study aimed to determine the mechanism through which TMEM16A maintains sperm volume during capacitation. The effects of TMEM16A were compared to those of CFTR and ClC3. Spermatozoa were capacitated in the presence of specific TMEM16A, CFTR, and ClC3 inhibitors, and the results showed that only TMEM16A inhibition increased acrosomal volume, leading to changes within the acrosome. Similarly, only TMEM16A inhibition prevented actin polymerization during capacitation. Further analysis showed that TMEM16A inhibition also prevented ERK1/2 and RhoA activation. On the other hand, TMEM16A and CFTR inhibition affected both capacitation and spontaneous acrosomal reaction, whereas ClC3 inhibition only affected the spontaneous acrosomal reaction. In conclusion, during capacitation, TMEM16A activity regulates acrosomal structure through actin polymerization and by regulating ERK1/2 and RhoA activities. Full article

Comprehensive land consolidation (CLC) significantly impacts farmers’ sustainable development, particularly in southwestern mountainous areas with limited alternative livelihood options. However, existing studies have rarely considered the impact of CLC on farmers’ livelihoods under different terrain gradients in mountainous areas. Therefore, this study employs elevation, slope, and the terrain position index to divide terrain gradient zones. Based on 307 responses from household survey data, this study measures the changes in farmers’ livelihood capital and livelihood strategies before and after CLC and analyzes the heterogeneity of the impact of CLC under different terrain gradients. The results show the following: (1) The growth of farmers’ livelihood capital and the net effect of CLC showed the terrain gradient effect of medium-terrain areas > low-terrain areas > high-terrain areas. (2) Traditional agricultural types are transitioning to modern agricultural types and agriculture multi-employment types, while agriculture multi-employment types are shifting to non-agriculture multi-employment types. (3) The direct impact of CLC on livelihood transformation is significant in the low-terrain areas, whereas in the medium-terrain and high-terrain areas, the effects are primarily indirect through livelihood factors. This study can provide suggestions for the sustainable development of farmers in different topographic gradients in the Anning River basin. Full article

Plant extracts contain many small molecules that are less investigated. The present paper aims to study in silico physical-chemical, pharmacokinetic, medicinal chemistry and lead/drug-likeness properties and the ability to interfere with the activity of P-glycoprotein (P-gp) transporter and cytochrome P450 (CYP) oxidase system in humans of phloridzin, phloretin, 4-methylchalcone metabolic series alongside the top three compounds found in the ethanolic extract from strawberries (S), namely 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, 2-pyrrolidinone 5-(cyclohexylmethyl) and hexadecanoic acid. The phloridzin derivatives also were studied for their inhibitory potential upon Bcl-2, TNKS1 and COX-2 molecular targets. In vitro, Caco-2 studies analyzed the cytoprotective and anti-proliferative activity of S and the three phloridzin derivatives (pure compounds) in comparison with their combination 1:1 (GAE/pure compound, w/w), in the range 1 to 50 µg active compounds per test sample. Altogether, it was concluded that phloretin (Phl) can be used alone or in combination with S to support intestinal cell health in humans. Phloridzin (Phd) and phloridzin combined with S were proven ineffective. 4-methylchalcone (4-MeCh) combined with S indicated no advantages, while the pure compound exhibited augmented inhibitory effects, becoming a candidate for combinations with anticancer drugs. Overall, in silico studies revealed possible limitations in the practical use of phloridzin derivatives due to their potential to interfere with the activity of several major CYP enzymes. Full article

This critical review evaluates chemical looping combustion using a syngas derived from gasified biomass (BMD Syngas). It is anticipated that establishing such a process will open new opportunities for CO₂ sequestration and the use of highly concentrated CO₂ in the manufacturing and synthesis of fuels from entirely renewable feedstocks. This review focuses on the process conducted through using two interconnected fluidized bed units: a nickel oxide reduction unit (an endothermic Fuel Reactor) and a nickel oxidation unit (an exothermic Air Reactor). In this respect, a high-performance OC (HPOC) with Ni on a γ-Al₂O₃ fluidizable support (20wt% Ni, 1wt% Co, 5wt% La/γ-Al₂O₃) was developed at the CREC (Chemical Reactor Engineering Centre) of the University of Western Ontario, Canada. The HPOC was studied in a CREC Riser Simulator. The benefits of this mini-fluidized unit are that it can be operated at 2–40 s reaction times, 550–650 °C temperatures, 1.3–2.5 H₂/CO ratios, and 0.5–1 biomass/syngas stoichiometric ratios, mimicking the conditions of industrial-scale CLC units. When using a syngas derived from biomass and the HPOC under these operating conditions, 90% CO, 92% H₂, and 88% CH4 conversions, together with a 91% CO₂ yield, were obtained. These results allowed the prediction of a 1.84–3.0 wt% ($g_{O_2}/g_{{OC}_{}}$) oxygen transport capacity, with a 40–70% nickel oxide conversion. The experimental data acquired with the CREC Riser Simulator permitted the development of realistic kinetic models. The resulting kinetics were used in combination with Computational Particle Fluid Dynamics (CPFD) to demonstrate the operability of a large-scale industrial syngas CLC process in a downer fuel unit. In addition, these CPFD simulations were employed to corroborate that high CO₂ yields are achievable in 12–15 m length downer fuel units. Full article

As an efficient management pattern to improve logistics efficiency through intensive management of construction materials, construction logistics centers (CLCs) have received active attention from academics and practitioners. However, the CLC location–allocation problem, which considers periodic demand and transportation risk, has not been adequately solved. This work provides an approach to integrating transportation path risk into multiperiod CLC location–allocation optimization for large-scale projects in complex environmental regions. For this purpose, this paper formulates a hybrid non-linear integer planning model to define this location–allocation problem and minimize the total cost of construction logistics and transportation risk. The model also incorporates critical features from realistic scenarios, including CLC’s service coverage, capacity constraints, and minimum utilization limits. We have designed an NSGA-II based on endocrine hormone regulation (EHR-NSGA-II) to solve the model. Finally, a large-scale railroad construction project in complex environmental regions is used as an example to prove the effectiveness of the model and algorithm. Compared with the single-period model, the multiperiod model designed in this paper provides a total cost reduction of 8.11% for the CLC location–allocation scheme. In addition, analyzing several key parameters provides valuable insights for managers to design more reliable construction logistics networks. Full article

Assessing land use/land cover changes currently represents an important avenue for achieving a better understanding of the urbanization phenomenon. Various free datasets based on satellite imagery are available, but the user should decide which one is the most suitable for their study area. The aim of the present paper is to perform an accuracy assessment of built-up areas using four datasets: Corine Land Cover Backbone (CLC Backbone), High Resolution Layers (HRL)–Imperviousness, Esri Land Cover and Dynamic World. The study case is represented by 12 major metropolitan areas (MAs) in Romania which have the most dynamic economic development and urban expansion. Confusion matrices were created, and the following metrics have been computed: overall accuracy (OA), kappa coefficient (k) and user accuracy (UA). The analysis was performed on three levels: for the entire surface of the MAs and separately for the urban and rural sides. The results at the metropolitan level show that even though CLC Backbone 2018 is the most suitable for extracting the built areas (0.85 overall accuracy), HRL and Esri Land Cover could also be used, as they share the same overall accuracy values (0.67). Significant differences exist between the urban and rural areas. CLC Backbone performed better in the rural areas (0.87) than in the urban areas (0.84). The other three datasets recorded major variations in the overall accuracy for the urban and rural areas. Esri Land Cover has the second greatest overall accuracy for the urban areas (0.81), while HRL is the second most accurate, after CLC Backbone, for assessing the rural areas (0.67). In conclusion, CLC Backbone has the best accuracy performance for all three levels of analysis. The significance of the study lies in the accuracy assessment results on the four datasets, performed at urban and rural levels. This paper aims to help researchers and decision makers choose the best dataset for assessing land use changes. Additionally, having a reliable dataset may help compute the indicators used to monitor the Sustainable Development Goals (SDGs). Full article

Artemisia dracunculus/(tarragon) is a perennial plant used in traditional medicine and the food industry. The plant is known to have beneficial effects on health, such as antibacterial, antifungal, antiseptic, carminative, anti-inflammatory, antipyretic, anthelmintic, etc. In this study, the compounds present in the highest concentrations in the essential oils obtained by different extraction methods from tarragon found on the Romanian market were identified by gas chromatography–mass spectrometry. The biological activity of these compounds was predicted using the computational tools ADMETlab3.0, admetSAR3.0, CLC-Pred2.0, and AntiBac-Pred. Also, the main molecular target of these compounds was predicted and the interactions with this protein were evaluated using molecular docking. The compounds identified in high concentrations in the obtained essential oils are estragole, cis-β-ocimene, trans-β-ocimene, limonene, eugenol methyl ether, eugenol acetate, eugenol, caryophyllene oxide, and α-pinene. The absorption, distribution, metabolism, excretion, and toxicity profiles of these compounds show that they are generally safe, but some of them can cause skin sensitization and respiratory toxicity and are potential inhibitors of the organic anion transporters OATP1 and OATP2. Several of these compounds exert antibacterial activity against some species of Staphylococcus, Streptococcus, and Prevotella. All compounds reveal potential cytotoxicity for several types of cancer cells. These findings may guide further experimental studies to identify medical and pharmacological applications of tarragon extracts or specific compounds that can be isolated from these extracts. Full article

Sandwich panels, consisting of two concrete wythes that encase an insulating core, are designed to improve energy efficiency and reduce the weight of construction applications. This research examines the thermal and flexural properties of a novel sandwich panel that incorporates ultra-high-performance fiber-reinforced concrete (UHPFRC) and cellular lightweight concrete (CLC) as its core material. Seven sandwich panel specimens were tested for their thermo-flexural performance using four-point bending tests. The experimental parameters included variations in UHPFRC thickness (20 mm and 30 mm) and different shear connector types (shear keys, steel bars, and post-tension steel bars). The study also assessed the effects of adding steel mesh reinforcement to the UHPFRC layer and evaluated the performance of UHPFRC box sections without a CLC core. The analysis concentrated on several critical factors, such as initial, ultimate, and serviceability loads, load–deflection relationships, load–end slip, load–strain relationships, composite action ratios, crack patterns, and failure modes. The thermal properties of the UHPFRC and CLC were evaluated using a transient plane source technique. The results demonstrated that panels using post-tension steel bars as shear connectors achieved flexural performance, and the most favorable composite action ratios reached 68.8%. Conversely, the box section exhibited a brittle failure mode when compared to the other sandwich panels tested. To effectively evaluate mechanical and thermal properties, it is important to design panels that have adequate load-bearing capacity while maintaining low thermal conductivity. This study introduced a thermo-mechanical performance coefficient to evaluate both the thermal and mechanical performance of the panels. The findings indicated that sandwich panels with post-tension steel bars achieved the highest thermo-mechanical performance, while those with steel connectors had the lowest performance. Full article

Background/Objectives: Carbapenem-resistant Klebsiella pneumoniae has become endemic in Europe, including in Italy, where its prevalence has risen dramatically, primarily due to epidemic clones harboring metallo-enzymes. This study aims to investigate the dissemination of K. pneumoniae strains co-producing OXA-48 and NDM-1 between two hospitals in southern Italy using molecular analyses. Methods: A total of 49 K. pneumoniae strains, predominantly co-producing OXA-48 and NDM-1, were collected between March and December 2023. Antibiotic susceptibility testing was conducted following EUCAST guidelines. Whole-genome sequencing (Illumina MiSeq) and bioinformatics tools (CARD, CLC Genomics Workbench) were used to identify resistance and virulence genes, capsule loci, and phylogenetic relationships. Results: All isolates exhibited multidrug-resistant or extensively drug-resistant profiles, including resistance to ceftazidime/avibactam and meropenem/vaborbactam. Genomic analysis revealed diverse resistance genes such as bla_OXA-48, bla_NDM-1, bla_CTX-M-15, and bla_SHV variants. Virulence genes associated with capsules, fimbriae, and siderophores were widespread. Most strains were classified as ST147 by MLST and contained various plasmids known to carry antimicrobial resistance. Phylogenetic analysis confirmed their clonal relatedness, highlighting the intra-hospital dissemination of high-risk clones. Conclusions: High-risk K. pneumoniae clones, particularly ST147, pose significant challenges in healthcare settings due to the extensive antimicrobial resistance driven by plasmid-borne resistance genes, including those that co-produce carbapenemases, like bla_NDM-1 and bla_OXA-48. Molecular monitoring of these clones is essential for improving targeted infection control strategies, mitigating the spread of multidrug-resistant pathogens, and managing their clinical impact effectively. Full article

This study investigated the removal of hydrogen sulfide (H₂S) from biogas using a laboratory-scale biofilter packed with biochar, cellular concrete waste (CLC waste), or polyurethane foam (PUF). The biofilter was tested under varied operational conditions, including H₂S concentrations ranging from 60 to 100 ppm and biogas flow rates of 0.2 to 1.0 L/min, to assess the removal efficiency and elimination capacity (EC). The COMSOL simulation framework was employed to predict biofilter performance and validate the experimental findings. The results revealed that removal efficiencies (REs) varied significantly across the packing materials and operational conditions. The biochar achieved RE values exceeding 92% and an EC of up to 150 g H₂S/m³/h, while the CLC waste demonstrated a moderate RE (~75%) and an EC of 100 g H₂S/m³/h. The PUF exhibited the lowest RE (~48%) but provided structural support for microbial colonization. Notably, the outlet (fourth and fifth) stages of the biofilter consistently outperformed the inlet stages (bottom and first stages), highlighting the influence of the residence time and microbial activity on H₂S removal. These findings provide a foundation for optimizing biofilter design and operational parameters to improve biogas purification efficiency. Full article

The pancake structure is the mainstream optical solution for virtual reality (VR) displays due to its compact, folded optical path. However, only a small portion of the light can pass through the pancake optical engine because the incident light has to be polarized and directed to the half mirror (HM) twice. In order to improve the optical efficiency, a new pancake optical engine is proposed for VR display, which employs a diffractive deflection film (DDF) with different focal lengths in three regions and two cholesteric liquid crystal (CLC) lenses that respond to circularly polarized light. The CLC lenses are modeled, and their polarization response characteristics are verified. The pancake system is simulated and optimized in terms of image quality and evaluated for optical efficiency, achieving 2.86 times the optical efficiency of the conventional pancake system, and the root mean square (RMS) radius of the system is controlled within 19 μm, and the modulation transfer function (MTF) at the cut-off frequency is greater than 0.2. The results indicate that this structure has great potential in the VR display field. Full article