Search Results (290)

Pyrochlore Bi_1.8Mn_0.5Ni_0.5Ta₂O_9-Δ (sp.gr. Fd-3m, a = 10.5038(9) Å) was synthesized by the solid-phase reaction method and characterized by vibrational and X-ray spectroscopy. According to scanning electron microscopy, the ceramics are characterized by a porous microstructure formed by randomly oriented oblong grains. The average crystallite size determined by X-ray diffraction is 65 nm. The charge state of transition element cations in the pyrochlore was analyzed by soft X-ray spectroscopy using synchrotron radiation. For mixed pyrochlore, a characteristic shift of Bi4f and Ta4f and Ta5p spectra to the region of lower energies by 0.25 and 0.90 eV is observed compared to the binding energy in Bi₂O₃ and Ta₂O₅ oxides. XPS Mn2p spectrum of pyrochlore has an intermediate energy position compared to the binding energy in MnO and Mn₂O₃, which indicates a mixed charge state of manganese (II, III) cations. Judging by the nature of the Ni2p spectrum of the complex oxide, nickel ions are in the charge state of +(2+ζ). The relative permittivity of the sample in a wide temperature (up to 350 °C) and frequency range (25–10⁶ Hz) does not depend on the frequency and exhibits a constant low value of 25. The minimum value of 4 × 10⁻³ dielectric loss tangent is exhibited by the sample at a frequency of 10⁶ Hz. The activation energy of conductivity is 0.7 eV. The electrical behavior of the sample is modeled by an equivalent circuit containing a Warburg diffusion element. Full article

Numerous scientific studies have confirmed the effectiveness of seed bioactivation using electromagnetic fields (EMFs) in agriculture. This article presents the results of the remote application of an EMF TOR device in the cultivation of barley Hordeum vulgare L. Laboratory studies and field tests were conducted, showing a positive effect on the growth and development of plants both when treating dry seeds before sowing and when treating sown seeds in the field. The optimal time period for EMF treatment was determined: treating air-dried seeds with EMFs before sowing for 10–15 min increased germination by 5–18% and the growth rate of seedlings by 2–3 times. The maximum observed effect occurred during the treatment period from 7:00 to 11:00. As a result of changing the balance of phytohormones, the further stimulation of the root system and the assimilation surface of plants was noted due to a 1.5-fold increase in the content of auxins. The density of productive stems, ear length, seed set, and 1000 seed weight increased, which ultimately led to an increase in yield by more than 10% and, in some varieties, to a decrease in the protein content in grains compared to the control variant (by 3–22%), bringing them closer to brewing conditions. Full article

A comprehensive paleoecological study of a forested bog located in the middle taiga subzone of northeastern European Russia was carried out. According to the ¹⁴C radiocarbon dating and botanical composition analysis, the bog began forming 8200 calibrated years ago, evolving in three stages from grassy wetlands to its current state as a pine-Sphagnum peatland. Analysis revealed substantial carbon storage (81.4 kg m⁻²) within the peat deposit. Macrocharcoal particles were consistently present throughout the peat deposits, demonstrating continuous fire activity across the bog’s developing. High charcoal particle accumulation rates occurred not only during warm periods like the Holocene thermal maximum but also during colder and wetter periods. These periods include recent centuries, when high charcoal accumulation rates are likely due to increased human activity. Statistical analysis showed significant relationships between macrocharcoal content and several peat characteristics: higher charcoal levels correlated with increased soil carbon (r = 0.6), greater aromatic compounds (r = 0.8), and elevated polycyclic aromatic hydrocarbons (r = 0.7), all with p < 0.05. These findings highlight how fire has consistently shaped this ecosystem’s development and carbon storage capacity over millennia, with apparent intensification during recent centuries potentially linked to anthropogenic influences on fire regimes in the boreal zone. Full article

Aging port infrastructure demands frequent and reliable inspections, yet the existing automated systems often require expensive industrial drones, posing significant adoption barriers for local governments with limited resources. To address this challenge, this study develops a low-cost, automated crack detection system for port quay walls utilizing orthophotos generated from a small general-purpose drone. The system employs the YOLOR (You Only Learn One Representation) object detection algorithm, enhanced by two novel image processing techniques—overlapping tiling and pseudo-altitude slicing—to overcome the resolution limitations of low-cost cameras. While official guidelines for port facilities designate 3 mm as an inspection threshold, our system is specifically designed to achieve a higher-resolution detection capability for cracks as narrow as 1 mm. This approach ensures reliable detection with a sufficient safety margin and enables the proactive monitoring of crack progression for preventive maintenance. The effectiveness of the proposed image processing techniques was validated, with an F₁ score-based analysis revealing key trade-offs between maximizing detection recall and achieving a balanced performance depending on the chosen simulated altitude. Furthermore, evaluation using real-world inspection data demonstrated that the proposed system achieves a detection performance comparable to that of a well-established commercial system, confirming its practical applicability. Crucially, by mapping the detected cracks to real-world coordinates on georeferenced orthophotos, the system provides a foundation for advanced, data-driven asset management, allowing for the quantitative tracking of deterioration over time. These results confirm that the proposed workflow is a practical and sustainable solution for infrastructure monitoring. Full article

Treadmills are a convenient tool to study animal gait and behavior. Traditional animal treadmill designs often entail preset speeds and therefore have reduced adaptability to animals’ dynamic behavior, thus restricting the experimental scope. Fortunately, advancements in computer vision and automation allow circumvention of these limitations. Here, we introduce a series of real-time adaptive treadmill systems utilizing both marker-based visual fiducial systems (colored blocks or AprilTags) and marker-free (pre-trained models) tracking methods powered by advanced computer vision to track experimental animals. We demonstrate their real-time object recognition capabilities in specific tasks by conducting practical tests and highlight the performance of the marker-free method using an object detection machine learning algorithm (FOMO MobileNetV2 network), which shows high robustness and accuracy in detecting a moving rat compared to the marker-based method. The combination of this computer vision system together with treadmill control overcome the issues of traditional treadmills by enabling the adjustment of belt speed and direction based on animal movement. Full article

High-albedo ground and wall materials are promoted to mitigate heat stress in tropical climates, yet conflicting evidence driven by climatic and metric variability make their impact on Outdoor Thermal Comfort (OTC) unclear. This study employed parametric simulations to assess how ground and wall albedo affect OTC, measured via the Universal Thermal Climate Index (UTCI) in typical urban canyons. Using ENVI-met, we tested ground albedo (0.2–0.8) and wall albedo (0.05–0.90) with emissivity fixed at 0.9. Findings reveal that ground albedo had a minimal impact on the UTCI (mean amplitude 0.44 °C), while wall albedo reduced the UTCI by up to 2.80 °C, prioritizing wall material selection for heat mitigation. It was also found that the increase in ground albedo offsets the cooling potential of high-albedo walls. Furthermore, differences in the impact under shaded and unshaded areas were observed. These results question assumptions of universal high-albedo benefits, recommending case-specific simulations in urban design. Full article

Increasing the use of healthcare facilities has resulted in the growing production of biomedical waste, which poses health risks to users, health professionals, and the environment. The aim of this research is to study the correlation between governance in Togo’s public health facilities and the quality of biomedical waste management within these facilities. Methods: This was a cross-sectional, descriptive, and analytical study conducted from September to December 2024. It involved 264 public health facilities of all types in all health regions of Togo. Health facilities were selected using the simple random selection technique. Healthcare providers were selected using the reasoned choice technique. The statistical tests used were the chi-square test and logistic regression, which enabled proportions to be compared and confounding factors to be eliminated, respectively. Results: Multivariate analysis revealed a statistically significant association between the organization and training component of governance and the quality of biomedical waste management (BMWM) in health facilities (OR = 3.79; 95% CI [1.79–8.03]; p < 0.001). This relationship suggests that health facilities with functional infection prevention and control (ICP) or BMWM committees, trained staff at all levels (nursing, technical, and administrative), and dedicated waste management personnel are more likely to implement compliant waste management practices. Analyses of the data also revealed that, among the criteria for assessing the quality of biomedical waste management (BMWM), the most significant were sorting (OR = 1.482; 95% CI [1.286; 1.708]), quantification (OR = 2.026; 95% CI [1.491; 2.753]), transportation (OR = 1.403; 95% CI [1.187; 1.66]), and disposal infrastructure (OR = 1.604; 95% CI [1.298; 1.982]). The application of this grid shows that 17.8% of the health facilities surveyed had a score equal to or above 80% on all the criteria used to assess the quality of biomedical waste management, and they were therefore managing waste in an “acceptable” manner. The study highlights key findings in biomedical waste management practices, providing actionable insights for improving public health safety. Full article

In Arctic residents, blood lipids fluctuate seasonally in response to changes in light exposure (LE) patterns. This study investigates which aspects of LE (timing, dynamic range, and duration) are related to lipid profiles. We analyzed actigraphy data measuring LE and blue light exposure (BLE) along with blood determinations from 27 residents across different seasons. We assessed circadian parameters of melatonin in a subset of participants. We found that features of BLE and melatonin significantly predicted lipids: An earlier BLE acrophase was associated with higher HDL-C (β = −0.246, p = 0.013). Nighttime BLE was positively associated with TC (β = 0.290, p = 0.008) and LDL-C (β = 0.253, p = 0.025). The normalized circadian amplitude of BLE was inversely associated with the TG/HDL ratio (β = −0.384, p < 0.001). Finally, earlier melatonin was associated with lower TG/HDL (β = 0.464, p = 0.007). Results remained significant after adjusting for co-factors of photoperiod duration, age, sex, and indigeneity. These findings suggest that patterns of LE (circadian light hygiene) could be a way to improve cardiovascular health. Full article

This study presents the influence of pH control agents and pH value on the physical properties of ZnO thin films obtained by chemical bath deposition. ZnO thin films were synthesized on glass substrates using precursor solutions of different pHs prepared from two bases: sodium hydroxide (NaOH) and ammonia (NH₃). The effect of pH values on the morphological, structural, and optical properties of ZnO thin films was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and UV–Visible spectroscopy. XRD results showed that all the synthesized ZnO thin films are polycrystalline and crystallize in a hexagonal wurtzite structure. The crystallite size, calculated using the Debye–Scherrer formula, varied from 10.50 nm to 11.69 nm for ZnO thin films obtained with NH₃ and from 20.79 nm to 27.76 nm for those obtained with NaOH. FTIR analysis confirmed the presence of functional groups. SEM images indicated that not only the base but also the pH affects the morphology of the films, giving rise to different granular shapes. Overall, the ZnO thin films obtained with NaOH looked more mesoporous compared to those obtained with NH₃. Optical characterization results showed that whatever the base used, the pH of the precursor solution affected the ZnO thin film transmittance. Films synthesized with NH₃ exhibited the best transmittance (80%) at pH 8.5, while the best transmittance (81%) of films synthesized with NaOH was obtained at pH 8 in the visible region. Based on optical and morphological properties, ZnO films obtained from NH₃ at pH 8.5 are found to be more suitable as photoanodes in dye-sensitized solar cells. Full article

Complex antimony pyrochlores Bi_2.7M_0.46Ni_0.70Sb₂O_10+Δ (M = Zn, Mg) were synthesized from oxide precursors, using the solid-state reaction method. For each composition variant, the pyrochlore phase formation process was studied during solid-state synthesis in the range of 500–1050 °C. The influence of zinc and magnesium on the phase formation process was established. The interaction of oxide precursors occurs at a temperature of 600 °C and higher, resulting in the formation of bismuth stibate (Bi₃SbO₇) as a binary impurity phase. Oxide precursors, including bismuth(III) and antimony(III,V) oxides, are fixed in the samples up to 750 °C, at which point the intermediate cubic phase Bi₃M_2/3Sb_7/3O₁₁ (sp. gr. Pn-3, M = Zn, Ni) is formed in the zinc system. Interacting with transition element oxides, it is transformed into pyrochlore. An intermediate phase with the Bi_4.66Ca_1.09VO_10.5 structure (sp. gr. Pnnm) was found in the magnesium system. The unit cell parameter of pyrochlore for two samples has a minimum value at 800 °C, which is associated with the onset of high-temperature synthesis of pyrochlore. The synthesis of phase-pure pyrochlores is confirmed by high-resolution Raman spectroscopy. The data interpretation showed that the cations in Ni/Zn pyrochlore are more likely to be incorporated into bismuth positions than in Ni/Mg pyrochlore. The nickel–magnesium pyrochlore is characterized by a low-porosity microstructure, with grain sizes of up to 3 μm, according to SEM data. Zinc oxide has a sintering effect on ceramics. Therefore, the grain size in ceramics is large and varies from 2 to 7 μm. Full article

The behavior of the spectra of symmetric block-type random matrices with symmetric blocks of high dimensionality is considered in this paper. Under minimal conditions regarding the distributions of matrix block elements (Lindeberg conditions), the universality of the limiting empirical distribution function of block-type random matrices is shown. Full article

The multifactorial modification of the structure and properties of alginate matrix was conducted using partially acetylated cellulose nanocrystals. Fourier-transform infrared spectroscopy and thermogravimetric analysis indicated the absence of chemical interactions between the polymer matrix and the filler. The surface texture was examined using optical microscopy and scanning electron microscopy, along with a reconstruction of its 3D model. With an increase in the content of nanoparticles in the composite, the following was revealed. Firstly, the roughness and density of the arrangement of surface elements increased, while their size decreased. Secondly, at pH values < 7, the puncture resistance increased, whereas the swelling coefficient of the films decreased. In Hanks solutions, the low solubility of the films was established, as well as a higher swelling coefficient at pH > 7. Thirdly, the contribution of donor centers to the free surface energy, cytocompatibility of composite films, and adhesion of fibroblasts to the surface increased. The hematological tests of the composites showed a procoagulant effect. Summarizing the data, we propose a model that explains the influence of nanocrystals and their concentration on the formation of the observed composites’ structure and their physicochemical and biological properties. The main driving forces of structurization are the factor of the excluded volume and interactions in a heterogeneous colloidal system. Full article

Reducing the use of chemical inputs (fertilizers, pesticides) in agriculture while maintaining crop productivity is the main challenge facing sub-Saharan African family farming systems. The use of effective microorganisms (EM) is among the various innovative approaches for minimizing chemical inputs and the environmental impact of agricultural production and protecting soil health while enhancing crop yields and improving food security. This study sought to characterize the microbial biodiversity of local beneficial microorganisms (BMs) products from locally fermented forest litter and investigate their ability to enhance tomato plant growth and development. Beneficial microorganisms (BMs) were obtained by anaerobic fermentation of forest litter collected in four agroecological regions of Senegal mixed with sugarcane molasses and various types of carbon sources (groundnut shells, millet stovers, and rice bran in different proportions). The microbial community composition was analyzed using next-generation rDNA sequencing, and their effects on tomato growth traits were tested in greenhouse experiments. Results show that regardless of the litter geographical collection site, the dominant bacterial taxa in the BMs belonged to the phyla Firmicutes (27.75–97.06%) and Proteobacteria (2.93–72.24%). Within these groups, the most prevalent classes were Bacilli (14.41–89.82%), α-proteobacteria (2.83–72.09%), and Clostridia (0.024–13.34%). Key genera included Lactobacillus (13–65.83%), Acetobacter (8.91–72.09%), Sporolactobacillus (1.40–43.35%), and Clostridium (0.08–13.34%). Fungal taxa were dominated by the classes Leotiomycetes and Sordariomycetes, with a prevalence of the acidophilic genus Acidea. Although microbial diversity is relatively uniform across samples, the relative abundance of microbial taxa is influenced by the litter’s origin. This is illustrated by the PCoA analysis, which clusters microbial communities based on their litter source. Greenhouse experiments revealed that five BMs (DK-M, DK-G, DK-GM, NB-R, and NB-M) significantly (p < 0.05) enhanced tomato growth traits, including plant height (+10.75% for DK-G and +9.44% for NB-R), root length (+56.84–62.20%), root volume (+84.32–97.35%), root surface area (+53.16–56.72%), and both fresh and dry shoot biomass when compared to untreated controls. This study revealed that forest-fermented litter products (BMs), produced using litter collected from various regions in Senegal, contain beneficial microorganisms known as plant growth-promoting microorganisms (PGPMs), which enhanced tomato growth. These findings highlight the potential of locally produced BMs as an agroecological alternative to inorganic inputs, particularly within Senegal’s family farming systems. Full article

Green belts, consisting mainly of natural forests, woodlands, and agricultural areas surrounding major cities, play an essential role in regulating urban development and controlling the expansion of metropolitan areas. Although this concept has been extensively studied in the world’s major metropolitan areas, it remains relatively unknown in many countries, particularly in Africa. There is a great need for research to better understand urban vegetation cover on the continent. This article proposes a systematic review of African publications on green cover for the period 2010 to 2024. A descriptive and thematic analysis of the selected scientific papers was carried out using a database established to examine the state of existing research and understanding of the management of these plant formations in Africa. The results of these analyses highlight several major challenges facing urban forestry, including increasing anthropogenic pressures, lack of urban planning that integrates urban forestry, and shortcomings in the management of existing forest landscapes. The thematic analysis has also helped to identify the topics addressed by African researchers, identify gaps in research, and suggest directions for future studies. Three priority areas emerge from this analysis: the conservation of natural or artificial green belts around cities, the impact of these forest landscapes on urban heat islands (climate impact), and the sustainability of ecosystem management in the context of sustainable urbanization. These guidelines will enable a better understanding and valorization of green belts in Africa, thus contributing to the construction of more sustainable cities and the efficient management of forest landscapes. Full article

Objective: Laccases are known to be able to degrade phenolic compounds to simpler components. The main objective of our study was to analyze this property in transgenic aspen plants carrying the laccase gene Lac from Trametes hirsuta which can be potentially used in soil phytoremediation. Methods: We created transgenic aspen plants carrying the laccase gene Lac from Trametes hirsute using the agrobacterial transformation of stem explants with the pBI–Lac vector containing the Lac gene from the white rot fungus T. hirsuta 072 (NCBI GenBank accession number KP027478). Transgenic plants were micropropagated and cultivated in vitro in lines. The degradation of 2,4,6-trichlorophenol (2,4,6-TCP) by plant roots was analyzed by mass-spectrometry with electron ionization using a gas chromatograph. Results: Although plants have their own laccases, those of fungal origin are more effective. All transgenic plants that expressed the recombinant gene degraded 2,4,6-TCP more effectively than non-transformed plants in the control (the degradation efficiency ranged 92 to 98% versus 82% in non-transformed control). Line 47Lac8 demonstrated a 16% higher efficiency than the non-transformed plants in the control. There was also an inverse relationship between the viability of a transgenic line and its level of expression of the recombinant gene. Thus, line 47Lac4 was not viable under native conditions, probably due to lignin synthesis disruptions during the initiation of secondary tissues. This is confirmed by changes in the expression of native genes of lignin biosynthesis. The rest of the transgenic lines did not differ significantly from control in wood growth and biochemistry. The transgenic plant roots were shown to preserve the ability to express the Lac gene ex vitro. Conclusions: Three transgenic lines (47Lac5, 47Lac8, and 47Lac23) with the Lac gene can be recommended for use in soil phytoremediation. Full article