Search Results (29,023)

The paper discusses the results of the concentrations of atmospheric particulate matter, in the PM_2.5 and PM₁₀ fractions, acquired by two low-cost sensors. The research was carried out from 1 July 2023 to 30 June 2024, in Palermo, Sicily. The results obtained from two systems equipped with the same sensor model were compared. Excellent linear correlation was observed between the results, with differences in measurements falling within instrumental accuracy. Two instruments equipped with different sensors, models Novasense SDS011 and Plantower PMSA003, were placed at the same site. These were complemented by a weather station to measure meteorological parameters. Upon comparing the atmospheric particulate matter concentrations measured by the two instruments, it was observed that there was a good linear correlation for PM_2.5 and a poor linear correlation for PM₁₀. Additionally, the PMSA003 sensor appeared to consistently record higher concentrations than the SDS011 sensor. During periods influenced by natural sources and/or anthropogenic activities at the regional and/or local scale, i.e., the dispersal of Saharan sands, forest fires, and local events using fireworks, abnormal concentrations of atmospheric particulate matter were detected. Despite the inherent limitations in precision and accuracy, both low-cost instruments were able to identify periods with abnormal concentrations of atmospheric particulate matter, regardless of their source or type. Full article

This paper presents the authentication analysis of a bronze bust of Napoleon I, attributed to the Italian artist Renzo Colombo (1856–1885) based on his signature and other casting and molding inscriptions. The bust was made using the lost wax technique and artificially patinated in the Pinédo variant workshop. This study combined historiographical research (using the specialized literature) with data from auction catalogs. These were compared with photographs of the entire bust and close-up images of key areas, including anthropomorphic features, clothing, inscriptions, and structural and ornamental details. The condition of the bust and its historical and chemical characteristics were assessed through direct analysis with magnifying tools and indirect analysis using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). Full article

Traditionally, “ancient villages” are communities that date back to a previous era, possess abundant traditional resources, and hold significant historical, social, cultural, ecological, and economic significance. This study examines the geographical and chronological development of 2957 traditional communities in the Yangtze River Basin and extensively employs GIS spatial analysis, geostatistical analysis, and historical literature review to study the evolution of the locations of traditional settlements under various factors. The study’s findings revealed that: (1) From a geographical standpoint, the traditional villages in the study area present a distribution state of “two cores, small aggregation, and many dispersions”. The two core clusters are located at the intersection of Hunan, Guizhou, and Chongqing provinces, where the natural geographical advantages attracted people from different dynasties to settle here. (2) From a temporal perspective, the quantity of traditional villages shows a growing trend, and the distribution center of each dynasty shows an east–west direction. Among them, the shift from the Song to the Yuan dynasties marked the period of greatest change in village distribution, which originated from the Song Dynasty’s quick economic growth. In addition, the village distribution was clustered in the eastern part of the country, adapting to the needs of commercial trade. When the Song Dynasty fell, the society was in turmoil, and the villages were transferred to the central region to avoid the war. The Yuan Dynasty also laid down the fundamental distribution pattern of conventional villages. (3) From the standpoint of choosing a village location, most of them are distributed in mountainous, hilly, and plain regions; the gentle slopes of 0°~15° are favored by people. Sufficient water sources, abundant precipitation, and a suitable climate are also necessary choices. (4) From the perspective of driving factors, traditional village distribution in the basin is impacted by historical, cultural, social, and ecological factors. Included among these, traditional village distribution is inversely connected with socio-economic variables. Under the interaction of two factors, the distribution will be more affected. To summarize, the complex human geographic factors together create the conventional village dispersal pattern, and examining these elements holds substantial practical importance for comprehending, safeguarding, and preserving traditional villages. Full article

A SAW device with a multi-layered piezoelectric substrate has excellent performance due to its high Q value. A multi-layer piezoelectric substrate combined with phononic crystal structures capable of acoustic wave reflection with a very small array can achieve miniaturization and high performance. In this paper, a honeycomb-shaped phononic crystal structure based on 42°Y-X LT/SiO₂/poly-Si/Si-layered substrate is proposed. The analysis of the bandgap distribution under various filling fractions was carried out using dispersion and transmission characteristics. In order to study the application of PnCs in SAW devices, one-port resonators with different reflectors were compared and analyzed. Based on the frequency response curves and Bode-Q value curves, it was found that when the HC-PnC structure is used as a reflector, it can not only improve the transmission loss of the resonator but also reduce the size of the device. Full article

Nickel manganese oxide (NiMnO₃) combines magnetic and dielectric properties, making it a promising material for sensor and supercapacitor applications, as well as for catalytic water splitting. The efficiency of its utilization is notably influenced by particle size. In this study, we investigate the influence of thermal treatment parameters on the phase composition of products from alkali co-precipitation of nickel and manganese (II) ions and identify optimal conditions for synthesizing phase-pure nickel manganese oxide. Ultrafine nanoparticles of NiMnO₃ (with sizes as small as 2 nm) are obtained via liquid-phase ultrasonic dispersion, exhibiting a narrow size distribution. A systematic exploration of the solvent nature (water, N-methyl-2-pyrrolidone, dimethyl sulfoxide, dimethylformamide) on the efficiency of ultrasonic dispersion of NiMnO₃ nanoparticles is provided. It is demonstrated that particle size is influenced not only by absorbed acoustic power, dependent on the physical properties of the used solvent (boiling temperature, gas solubility, viscosity, density) but also by the chemical stability of the solvent under prolonged ultrasonic treatment. Our findings provide insights for designing ultrasonic treatment protocols for nanoparticle dispersions with tailored particle sizes. Full article

TiO₂ used for photocatalytic water purification is most active in the form of nanoparticles (NP), but their use is fraught with difficulties in separation from solution or/and a tendency to agglomerate. The novel materials designed in this work circumvent these problems by immobilizing TiO₂ NPs on the surface of exfoliated clay minerals. A series of TiO₂/clay mineral composites were obtained using five different clay components: the Na-, CTA-, or H-form of montmorillonite (Mt) and Na- or CTA-form of laponite (Lap). The TiO₂ component was prepared using the inverse microemulsion method. The composites were characterized with X-ray diffraction, scanning/transmission electron microscopy/energy dispersive X-ray spectroscopy, FTIR spectroscopy, thermal analysis, and N₂ adsorption–desorption isotherms. It was shown that upon composite synthesis, the Mt interlayer became filled by a mixture of CTA⁺ and hydronium ions, regardless of the nature of the parent clay, while the structure of Lap underwent partial destruction. The composites displayed high specific surface area and uniform mesoporosity determined by the size of the TiO₂ nanoparticles. The best textural parameters were shown by composites containing clay components whose structure was partially destroyed; for instance, Ti/CTA-Lap had a specific surface area of 420 m²g⁻¹ and a pore volume of 0.653 cm³g⁻¹. The materials were tested in the photodegradation of methyl orange and humic acid upon UV irradiation. The photocatalytic activity could be correlated with the development of textural properties. In both reactions, the performance of the most photoactive composites surpassed that of the reference commercial P25 titania. Full article

Urethane surfactants (REQ) were synthesized with octadecanol ethoxylate (AEO) and isocyanate methacrylate (IEM). Subsequently, reactive-carbamate-surfactant-modified nanomicrospheres (PER) were prepared via two-phase aqueous dispersion polymerization using acrylamide (AM), 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and ethylene glycol dimethacrylate (EGDMA). The microstructures and properties of the nanomicrospheres were characterized and examined via infrared spectroscopy, nano-laser particle size analysis, scanning electron microscopy, and in-house simulated exfoliation experiments. The results showed that the synthesized PER nanomicrospheres had a uniform particle size distribution, with an average size of 336 nm. The thermal decomposition temperature of the nanomicrospheres was 278 °C, and the nanomicrospheres had good thermal stability. At the same time, the nanomicrospheres maintained good swelling properties at mineralization < 10,000 mg/L and temperature < 90 °C. Under the condition of certain permeability, the blocking rate and drag coefficient gradually increased with increasing polymer microsphere concentration. Furthermore, at certain polymer microsphere concentrations, the blocking rate and drag coefficient gradually decreased with increasing core permeability. The experimental results indicate that nanomicrospheres used in the artificial core simulation drive have a better ability to drive oil recovery. Compared with AM microspheres (without REQ modification), nanomicrospheres exert a more considerable effect on recovery improvement. Compared with the water drive stage, the final recovery rate after the drive increases by 23.53%. This improvement is attributed to the unique structural design of the nanorods, which can form a thin film at the oil–water–rock interface and promote oil emulsification and stripping. In conclusion, PER nanomicrospheres can effectively control the fluid dynamics within the reservoir, reduce the loss of oil and gas resources, and improve the economic benefits of oil and gas fields, giving them a good application prospect. Full article

In recent decades, the study of discrete distributions has received increasing attention in the field of statistics, mainly because discrete distributions can model a wide range of count data. One common distribution used for modeling count data, for instance, is the negative binomial distribution (NBD), which performs well with over-dispersed data. In this paper, a new count distribution is introduced, called the conflation of negative binomial and logarithmic distributions, which is formed by conflating the negative binomial and logarithmic distributions, resulting in a distribution that possesses some of the properties of negative binomial and logarithmic distributions. The distribution has two parameters and is verified by a positive integer. Two modifications are proposed to the distribution, which includes zero as a support point. The new distribution is valuable from a theoretical perspective since it is a member of the weighted negative binomial distribution family. In addition, the distribution differs from the NBD in the sense that the probability of lower counts is inflated. This study discusses the characteristics of the proposed distribution and its modified versions, such as moments, probability generating functions, likelihood stochastic ordering, log-concavity, and unimodality properties. Real-world data are used to evaluate the performance of the proposed models against other models. All computations shown in this paper were produced using the R programming language. Full article

Mining activities, particularly in large excavations like the Bingham Canyon Copper Mine in Utah, have been increasingly linked to respiratory conditions due to heavy-metal-enriched waste and dust. Operating continuously since 1906, the Bingham Canyon Copper Mine contributes 4.4% of the Salt Lake Valley PM2.5 pollution. However, the extent of its contributions to larger-sized particulate matter (PM10) dust, soil and water contamination, and human health impacts is largely unknown. Aerosol optical depth data from Sentinel-2 imagery revealed discernible dust clouds downwind of the mine and smelter on non-prevailing-wind days, suggesting potential heavy metal dispersion from this fugitive dust and subsequent deposition to nearby surface soils. Our analysis of topsoils from across the western Salt Lake Valley found mean arsenic, copper, lead, and zinc concentrations to be well above global background concentrations. Also, the minimum values for arsenic and maximum values for lead were well above the US EPA regional screening levels for residential soils. Thus, arsenic is the metal of greatest concern for impacts on human health. Elevated concentrations of all metals were most notable near the mine, smelter, and tailings pond. Our study linked these elevated heavy metal levels to regional asthma outcomes through cluster analysis and distance-related comparison tests. Significant clusters of high asthma rates were observed in regions with elevated topsoil heavy metal concentrations, impacting both low- and high-income neighborhoods. The findings of this preliminary study suggest that the mine, smelter, and recent construction activities, especially on lands reclaimed from former tailings ponds, could be contributing to atmospheric dust containing high levels of heavy metals and exacerbating asthma outcomes for residents. However, the methods used in the study with aggregated health outcome data cannot determine causal links between the heavy metal contents of soil and health outcomes; they can only point to potential links and a need for further investigation. Such further investigation should involve individual-level data and control for potential confounding factors, such as socioeconomic status, access to healthcare, and lifestyle factors, to isolate the effect of metal exposures on asthma outcomes. This study focused on atmospheric deposition as a source of heavy metal enrichment of topsoil. However, future research is also essential to assess levels of heavy metals in subsoil parent materials and local surface and groundwaters to be able to assess the links between the sources or methods of soil contamination and health outcomes. Full article

Phospholipids are the main building components of cell membranes and are also used for cell signaling and as energy storages. Cancer cells alter their lipid metabolism, which ultimately leads to an increase in phospholipids in cancer tissue. Surgical energy instruments use electrical or vibrational energy to heat tissues, which causes intra- and extracellular water to expand rapidly and degrade cell structures, bursting the cells, which causes the formation of a tissue aerosol or smoke depending on the amount of energy used. This gas phase analyte can then be analyzed via gas analysis methods. Differential mobility spectrometry (DMS) is a method that can be used to differentiate malignant tissue from benign tissues in real time via the analysis of surgical smoke produced by energy instruments. Previously, the DMS identification of cancer tissue was based on a ‘black box method’ by differentiating the 2D dispersion plots of samples. This study sets out to find datapoints from the DMS dispersion plots that represent relevant target molecules. We studied the ability of DMS to differentiate three subclasses of phospholipids (phosphatidylcholine, phosphatidylinositol, and phosphatidylethanolamine) from a control sample using a bovine skeletal muscle matrix with a 5 mg addition of each phospholipid subclass to the sample matrix. We trained binary classifiers using linear discriminant analysis (LDA) and support vector machines (SVM) for sample classification. We were able to identify phosphatidylcholine, -inositol, and -ethanolamine with SVM binary classification accuracies of 91%, 73%, and 66% and with LDA binary classification accuracies of 82%, 74%, and 72%, respectively. Phosphatidylcholine was detected with a reliable classification accuracy, but ion separation setups should be adjusted in future studies to reliably detect other relevant phospholipids such as phosphatidylinositol and phosphatidylethanolamine and improve DMS as a microanalysis method and identify other phospholipids relevant to cancer tissue. Full article

Synthetic microwave focusing methods have been widely adopted in qualitative medical imaging to detect and localize anomalies based on their electromagnetic scattering signatures. This paper discusses the principles, challenges, and limitations of synthetic microwave-focusing techniques in medical applications. It is shown that the various focusing techniques, including time reversal, confocal imaging, and delay-and-sum, are all based on the scalar solution of the electromagnetic scattering problem, assuming the imaged object, i.e., the tissue or object, is linear, reciprocal, and time-invariant. They all aim to generate a qualitative image, revealing any strong scatterer within the imaged domain. The differences among these techniques lie only in the assumptions made to derive the solution and create an image of the relevant tissue or object. To get a fast solution using limited computational resources, those methods assume the tissue is homogeneous and non-dispersive, and thus, a simplified far-field Green’s function is used. Some focusing methods compensate for dispersive effects and attenuation in lossy tissues. Other approaches replace the simplified Green’s function with more representative functions. While these focusing techniques offer benefits like speed and low computational requirements, they face significant ongoing challenges in real-life applications due to their oversimplified linear solutions to the complex problem of non-linear medical microwave imaging. This paper discusses these challenges and potential solutions. Full article

This paper addresses the study of synoptic-scale meteorological conditions that favor long-range pollen transport in southern South America combining airborne pollen counts, modeled three-dimensional backward trajectories, and synoptic and surface meteorological data. Alnus pollen transport trajectories indicate origins predominantly in montane forests of the Yungas between 1500 and 2800 m altitude. The South American Low-Level Jet is the main meteorological feature that explains 64% of the detected pollen arrival at the target site. Podocarpus and Nothofagus pollen instead are linked primarily to the widespread Subantartic forests in southern Patagonia. Their transport patterns are consistent with previous studies, which show an association with synoptic patterns related to cold front passages carrying pollen in the free atmosphere (27% for Nothofagus and 25% for Podocarpus). These results show the significance of understanding long-distance pollen transport for disciplines such as climate change reconstruction and agriculture, emphasizing the need for further research to refine atmospheric circulation models and refine interpretations of past vegetation and climate dynamics. Full article

Residuals are essential in regression analysis for evaluating model adequacy, validating assumptions, and detecting outliers or influential data. While traditional residuals perform well in linear regression, they face limitations in exponential family models, such as those based on the binomial and Poisson distributions, due to heteroscedasticity and dependence among observations. This article introduces a novel standardized combined residual for linear and nonlinear regression models within the exponential family. By integrating information from both the mean and dispersion sub-models, the new residual provides a unified diagnostic tool that enhances computational efficiency and eliminates the need for projection matrices. Simulation studies and real-world applications demonstrate its advantages in efficiency and interpretability over traditional residuals. Full article

Nanostructured polymer-dispersed liquid crystals (nano-PDLCs) are transparent and optically isotropic materials in which submicron-sized liquid crystal (LC) domains are dispersed within a polymer matrix. Nano-PDLCs can induce birefringence by applying an electric field (E-field) based on the reorientation of the LC molecules. If nano-PDLCs are utilized as light-scattering-less birefringence memory materials, it is necessary to suppress the relaxation of the LC molecule orientation after the removal of the E-field. We focused on the ferroelectric smectic A (SmA) phase to suppress the relaxation of LC molecules, owing to its layered structure and high viscosity. Although nano-PDLCs require a strong E-field to reorient their LC molecules because of the anchoring effect at the LC/polymer interface, the required field strength can be reduced using a ferroelectric smectic A (SmA_F) LC with a large dielectric constant. In this study, we fabricated a nano-PDLC by shining an ultraviolet light on a mixture comprised an SmA_F LC, photocurable monomers, and a photo-initiator. The electro-birefringence effect was evaluated using polarizing optical microscopy. After the removal of the E-field, an enhanced memory effect was observed in the sample using SmA_F LC compared with nematic LC-based nano-PDLCs. Full article

Background/Objectives: A biocomposite based on magnesium-doped hydroxyapatite and enriched with amoxicillin (MgHApOx) was synthesized using the coprecipitation method and is presented here for the first time. Methods: The stability of MgHAp and MgHApOx suspensions was evaluated by ultrasound measurements. The structure of the synthesized MgHAp and MgHApOx was examined with X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The crystalline structure was determined by X-ray diffraction. The FTIR data were collected in the range of 4000–400 cm⁻¹. The morphology of the nanoparticles was evaluated by scanning electron microscopy (SEM). Furthermore, the biocompatible properties of MgHAp, MgHApOx and amoxicillin (Ox) suspensions were assessed using human fetal osteoblastic cells (hFOB 1.19 cell line). The antimicrobial properties of the MgHAp, MgHApOx and Ox suspension nanoparticles were assessed using the standard reference microbial strains Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 and Candida albicans ATCC 10231. Results: X-ray studies have shown that the biocomposite retains the characteristics of HAp and amoxicillin. The SEM assessment exhibited that the apatite contains particles at nanometric scale with acicular flakes morphology. The XRD and SEM results exhibited crystalline nanoparticles. The average crystallite size calculated from XRD analysis increased from 15.31 nm for MgHAp to 17.79 nm in the case of the MgHApOx sample. The energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analysis highlighted the presence of the constituent elements of MgHAp and amoxicillin. Moreover, XPS confirmed the substitution of Ca²⁺ ions with Mg²⁺ and the presence of amoxicillin constituents in the MgHAp lattice. The results of the in vitro antimicrobial assay demonstrated that MgHAp, MgHApOx and Ox suspensions exhibited good antimicrobial activity against the tested microbial strains. The results showed that the antimicrobial activity of the samples was influenced by the presence of the antibiotic and also by the incubation time. Conclusions: The findings from the biological assays indicate that MgHAp and MgHApOx are promising candidates for the development of new biocompatible and antimicrobial agents for biomedical applications. Full article