Stable Composition Research Articles

Utilizing magnetic xanthan gum nanocatalyst for the synthesis of acridindion derivatives via functionalized macrocycle Thiacalix[4]arene

An effective method for synthesizing acridinedione derivatives using a xanthan gum (XG), Thiacalix[4]arene (TC4A), and iron oxide nanoparticles (IONP) have been employed to construct a stable composition, which is named Thiacalix[4]arene-Xanthan Gum@ Iron Oxide Nanoparticles (TC4A-XG@IONP). The process used to fabricate this nanocatalyst includes the in-situ magnetization of XG, its amine modification by APTES to get NH2-XG@IONP hydrogel, the synthesis of TC4A, its functionalization with epichlorohydrine, and eventually its covalent attachment onto the NH2-XG@IONP hydrogel. The structure of the TC4A-XG@IONP was characterized by different analytical methods including Fourier-transform infrared spectroscopy, X-Ray diffraction analysis (XRD), Energy Dispersive X-Ray, Thermal Gravimetry analysis, Brunauer–Emmett–Teller, Field Emission Scanning Electron Microscope and Vibration Sample Magnetomete. With magnetic saturation of 9.10 emu g−1 and ~ 73% char yields, the TC4As-XG@IONP catalytic system demonstrated superparamagnetic property and high thermal stability. The magnetic properties of the TC4A-XG@IONP nanocatalyst system imparted by IONP enable it to be conveniently isolated from the reaction mixture by using an external magnet. In the XRD pattern of the TC4As-XG@IONP nanocatalyst, characteristic peaks were observed. This nanocatalyst is used as an eco-friendly, heterogeneous, and green magnetic catalyst in the synthesis of acridinedione derivatives through the one-pot pseudo-four component reaction of dimedone, various aromatic aldehydes, and ammonium acetate or aniline/substituted aniline. A combination of 10 mg of catalyst (TC4A-XG@IONP), 2 mmol of dimedone, and 1 mmol of aldehyde at 80 °C in a ethanol at 25 mL round bottom flask, the greatest output of acridinedione was 92% in 20 min.This can be attributed to using TC4A-XG@IONP catalyst with several merits as follows: high porosity (pore volume 0.038 cm3 g−1 and Pore size 9.309 nm), large surface area (17.306 m2 g−1), three dimensional structures, and many catalytic sites to active the reactants. Additionally, the presented catalyst could be reused at least four times (92–71%) with little activity loss, suggesting its excellent stability in this multicomponent reaction. Nanocatalysts based on natural biopolymers in combination with magnetic nanoparticles and macrocycles may open up new horizons for researchers in the field.

Increased monocarbonate formation during long-term hydration of CAC-limestone binder by calcium sulfate addition – A temperature-dependent XRD study

The long-term hydration of a mix with and without gypsum addition was investigated at 10, 23 and 40 °C by QXRD analysis. In addition, thermodynamic modelling was performed on all systems using GEMS to determine the stable phase composition and the influence of water loss during hydration. The results show that the formation of conversion-sensitive phases such as CAH10 is accelerated at 10 °C and hindered at 23 and 40 °C by the addition of gypsum. Moreover, at all different temperatures, monocarbonate forms next to AH3 as the main hydrate phase and the final phase composition is reached after at least 14 d (at 23 °C and 40 °C already after 2 d). Formation of low amounts ettringite only occurs at 10 and 23 °C during the entire storage time. At 40 °C, however, ettringite is not observed, which is probably due to water loss in the mix until 2 d.

МИНЕРАЛЬНЫЙ СОСТАВ КАК МАРКЕР ТЕРРИТОРИАЛЬНОЙ ПРИНАДЛЕЖНОСТИ ВИН ЗАЩИЩЕННЫХ НАИМЕНОВАНИЙ МЕСТ ПРОИСХОЖДЕНИЯ

The paper discusses methods for identifying wines based on regional characteristics, which consists of establishing a connection between the component composition of wines and soils corresponding to the area where grapes grow. It has been shown that markers of regional affiliation can be components whose content in wines practically does not change during the production process. The results of a study of the mineral composition of wines produced by the winemaking enterprise OOO “Imenie Sikory” are presented. Using atomic absorption spectroscopy using the Kvant Z spectrometer (NPF OOO “KORTEK”, Russia), 12 metal elements (Co, Mn, Rb, Cr, Cs, Al, Ba, Zn, Sr, Li, Na, Mg) were determined in the course of studies on atomic emission and absorption spectra. A study was also conducted of the mineral composition of soil samples from vineyards where grapes used for wine production grew. Using the methods of correlation and cluster analysis, as well as using the “random forest” algorithm (for wine samples, the initial data were the content of elements and their pairwise ratios), it was revealed that the mineral composition can serve as a marker of the regional affiliation of wine products, since the studied wine samples are within each variety have a stable mineral composition, regardless of the year of harvest (correlations between the year and the content of elements are insignificant), determined by the characteristics of the site where the grapes grow. Quantitative determination of the components of the mineral complex in combination with mathematical processing of the results allows us to establish the origin of the wines with a reasonable degree of probability. The mineral composition of the studied wines is unique and is determined by the soil characteristics of the vineyard areas of the “Semigorye” geographical object.

The influence of environmental factors on the composition of the petrophytic-steppe communities in the south of the Sverdlovsk and in the north of the Chelyabinsk regions

The investigated petrophytic-steppe communities of the Middle Urals do not belong to the zonal vegetation type. Their growth in the region is associated with an unusual combination of environmental conditions - well-drained, well-heated rocky riverbank slopes of the southern and close exposures of slopes. The aim of the work was to identify the key environmental parameters that determine the composition and structure of petrophytic-steppe communities in the south of the Sverdlovsk and north of the Chelyabinsk regions. The communities of the coastal slopes of the Iset, Bagaryak, Patrushikha, Sysert and Neiva rivers were studied. An array of 74 geobotanical releves of communities from 8 plots was collected, considering environmental factors, and the composition and structure of plant communities on plots of 1 m2 were also detailed. Using the CCA method of ordination, the contribution of environmental parameters to the variation in vegetation cover characteristics was estimated. It was shown that the parameters characterizing the type of rocks, as well as indicators of the amount of precipitation, have the greatest contribution. Four variants of combination of species in the studied communities, gravitating to certain sets of environmental parameters, were identified, for each of the groups a stable composition of dominant species was noted, and species characterized by a high level of constancy were identified.

Evaluation of the impact of tragacanth/xanthan gum interpolymer complexation with chitosan on pharmaceutical performance of gels with secnidazole as potential periodontal treatment

Periodontitis consists a group of dental disorders that affect about 70 % of the world population. The therapy mainly relies on mechanical removing bacterial biofilm, nevertheless, local or systemic antibacterial agents play a key role in treating the acute conditions. Secnidazole is a newer derivative of commonly used metronidazole with high safety profile and broad spectrum of antimicrobial activity. The aim of the study was to evaluate the applicability of polyelectrolyte complex-based hydrogels composed of anionic tragacanth with addition of xanthan gum and cationic chitosan as carriers for buccal/intra pocket delivery of secnidazole. Prepared hydrogels with 5 % and 10 % (w/w) drug content were evaluated pharmaceutically towards inter alia physicomechanical, rheological and thermal properties, drug release kinetics, swelling behavior or antimicrobial activity. Cytotoxicity against human primary umbilical vein endothelial cells was also assessed with two independent method. Stable compositions with secnidazole were obtained, however, various miscibility of the drug with the polymers was noted. By adding chitosan, antibacterial activity and swelling performance of the gels were improved, nevertheless, drop of the mucoadhesiveness was also recorded. Hydrogels with 5 % secnidazole were selected as effective antimicrobial compositions with the highest cytocompatibility. They might be considered as promising for oromucosal application with special attention given to SEC as an alternative locally administered antimicrobial agent.

Evaluating the capacity of heavy metal pollution enrichment in green vegetation in the industrial zone, Northwest China

It focused on heavy metal pollution of green vegetation in Tuokexun County, Xinjiang Northwest China's suburban industrial area, using inductively coupled plasma emission spectrometer to analyze the samples for Mn, Ni, Zn, Cd, Hg, Pb, As, Cu, and Cr contents. The soil's heavy metal content in the study area indicated a minor level of pollution overall (P = 1.77), with the most severe contamination being Hg, which is more likely to be caused by human activities. Heavy metal elements in trees have the most stable composition in comparison to grass and shrubs, with varying concentrations across different vegetation. The concentrations of Mn, Cd and Hg were highest in the Haloxylon ammodendron, Ni in Morus alba, Pb, As and Cu in Nitraria tangutorums, and Cr in Phragmites australis. Heavy metal restoration is most effectively performed by shrubs, and there are disparities in heavy metal enrichment among various vegetation. No significant difference was found in heavy metal enrichment between the aboveground and underground parts of vegetation. Based on the average of the membership function, Tamarix exhibits the strongest ability to enrich heavy metals, while Nitraria tangutorum comes in second, and Cynanchum chinense R.Br. is the least effective among all plant species. Morus alba is recommended as the primary planting species in the area. Nitraria tangutorum and Haloxylon ammodendron have good potential for Cd and As restoration and can be used as supporting vegetation.

Variations in the Vascular Bundle and Fiber Structure during the Stem Development of Rattan (Calamus caesius Blume)

Calamus caesius is one of the most well-known commercial climbing palm species across the world. A comprehensive understanding of the growth-dependent variation in microstructure and polymer distribution can provide fundamental information to guide its end-use applications. In this study, we investigated the age-wise characteristics of rattan stems and the ultrastructure of fibers using electron microscopy, light microscopy, and FTIR. The results showed that the frequency of vascular bundles with a diameter of 0.55∼0.62 mm in C. caesius was 3.49∼3.97 pieces/mm2. The diameter and length of the metaxylem vessel were 0.32∼0.34 mm and 2.86∼3.00 mm, respectively. Cellulose, lignin, xylan, and HCA are mainly concentrated in the fiber sheath of vascular bundles. The distribution of major polymers in positions other than the top was relatively stable. The tissue proportion of parenchyma, xylem, and phloem did not differ significantly at different positions. The proportion of fibers from 22.27%∼25.33% showed significant differences. The fiber length was 1.43∼1.76 mm, and the diameter was 10.78∼12.63 μm. During the growth process of the rattan stem, the secondary wall of fiber cells continued to accumulate inward towards the cell cavity from 2 to 6 layers. The unique fiber properties and stable vascular bundle composition of C. caesius may have potential in fields such as composite materials or renewable energy.

Effective Ti-6Al-4V Powder Recycling in LPBF Additive Manufacturing Considering Powder History

Laser powder bed fusion (LPBF) is an outstanding additive manufacturing (AM) technology that can enable both complicated geometries and desired mechanical properties in high-value components. However, the process reliability and cost have been the obstacles to the extensive industrial adoptions of LPBF. This work aims to develop a powder recycling procedure to reduce production cost and minimize process uncertainties due to powder degradation. We used a recycle index (R) to reuse Ti-6Al-4V powder through 10 production cycles. Using this recycle index is more reasonable than simply replying on recycle numbers as it incorporates the powder usage history. A recycling procedure with simple virgin powder top-up can effectively mitigate powder degradation and maintain stable powder properties, chemical compositions, and tensile properties. The experimental finding points to a sustainable recycling strategy of Ti alloy powders with minimal material waste and without noticeable detriment to observed mechanical performance through LPBF production cycles.

Study of the Effect of Adding Nb2O5 on Calcium Titanate-Based Ferroelectric Ceramics

This paper considers the effect of adding niobium oxide (Nb2O5) to ferroelectric ceramics based on calcium titanate (CaTiO3), and establishes a connection between the observed alterations in strength and dielectric properties and the variation in the Nb2O5 dopant concentration in the ceramics’ composition. The method of mechanochemical solid-phase synthesis was used as the main method for obtaining the ceramics, followed by thermal sintering under specified conditions in order to form a stable phase composition of the ceramics, and to initialize phase transformations in the composition. Based on the assessment of the phase composition of the resulting ceramics, it was determined that a growth in the Nb2O5 dopant concentration beyond 0.10 mol results in the formation of an orthorhombic-phase CaNb2O4 of the Pbcm(57) spatial system, the weight contribution of which grows. A growth in the Nb2O5 additive concentration results in the formation of two-phase ceramics, the formation of which allows for an enhancement in the mechanical strength of ceramics and resistance to external influences. During the study of the dependence of the strength properties on the dopant concentration alteration, a three-stage change in hardness and crack resistance was established, regarding both structural ordering and phase transformations. The measurement of dielectric characteristics showed the direct dependence of dielectric losses and the dielectric constant on the phase composition of ceramics.

Microbial Community Composition as an Indicator of the State of Basins Located at the Sea Coast (Exemplified by the Kanda Bay, Kandalaksha Gulf, White Sea)

Abstract—Formation of the Kanda Bay resulted from construction of a railway dam (1916) and subsequent isolation of the sea lagoon from the main basin of the Kandalaksha Gulf, White Sea. Decreased action of tidal flows, which mix the water column of the lagoon, altered the hydrological regime of the basin. Decreased water exchange resulted in formation of oxygen-depleted near-bottom water and to sulfide contamination. A freshwater lake was, however, preserved in the southern part of the Kanda Bay. The composition of microbial communities was studied for the near-bottom water horizons at different sides of the Kanda Bay. The oxygen regime in this layer was found to change, with increasing concentrations of sulfide and methane and active processes of sulfate reduction and methane oxidation. The composition of the microbial community changed noticeably, with lower abundance of true marine and freshwater microorganisms and development of bacteria and archaea predominant in microbial communities of anoxic water in meromictic basins. Among the microbial diversity, indicator species with increased abundance were revealed. These are archaea of the genera Methanoregula and Methanosaeta (phylum Halobacterota). The sulfur cycle microorganisms, which were the indicators of stagnant marine water, included anoxygenic phototrophic bacteria of the class Chlorobia, (Chlorobium phaeovibrioides, Pelodictyon phaeoclathratiforme), Chloroflexi of the genus Chloronema, nonsulfur purple bacteria related to the genus Rhodoferax, colorless sulfur bacteria of the family Beggiatoaceae, and sulfur oxidizers of the genus Thiobacillus. Archaea of the genus Nitrosopumilus (phylum Crenarchaeota) and bacteria of the genus Woeseia may be considered opposites to the indicator microorganisms, since they were found only in the open sea water. In our opinion, stable water exchange through the dam will result in the stable composition of the Kanda Bay microbial community, with only seasonal variations and year-to-year fluctuations. The negative scenario supports prediction of conversion of the Kanda Bay into a stratified basin with anoxic near-bottom water and the microbial community similar to that found in meromictic lakes.

The green macroalga Caulerpa prolifera replaces seagrass in a nitrogen enriched, phosphorus limited, urbanized estuary

The Indian River Lagoon (IRL) on Florida’s east-central coast is a highly developed eutrophic estuary, experiencing harmful algal blooms (HABs). Beginning in 2011, the IRL experienced multiple phytoplankton HABs that were followed by widespread seagrass losses and expanding blooms of the rhizophytic macroalga Caulerpa prolifera. To better understand factors related to the changing benthic cover, long-term monitoring data spanning 2011–2020 for seagrass and C. prolifera percent cover at six locations in the northern IRL and Banana River Lagoon were considered in multivariate analyses with environmental parameters (temperature, salinity, pH, dissolved oxygen, etc.), dissolved nutrient and chlorophyll-a concentrations, and macroalgal carbon (δ13C) and nitrogen (δ15N) stable isotopes, elemental composition (%C, %N, %P), and nutrient ratios (C:N:P). Data reduction using the global Bio-Env + STepwise (BEST) procedure followed by linkage tree (LINKTREE) analyses indicated the variable most correlated to annual differences in benthic cover was macroalgal C:P. Following seagrass losses, P availability increased, as the result of heavy rainfall, increased sediment flux, and/or more bioavailable P due to seagrass losses. The most correlated variables among differences in location were C:P, δ13C, and salinity, which could be related to less urbanization at the northernmost sites that had lower percent cover of C. prolifera. While not identified as a significant variable, the increase in C. prolifera was associated with four years (2016–2019) of high ammonium concentrations (6.26 µM) and macroalgal δ15N values (+8.67 ‰), linking the blooms to the influence of human waste. The variables identified in this work as related to benthic cover suggest that reducing stormwater runoff and inputs of human waste will promote the recovery of seagrasses in the IRL. These findings have implications for urbanized estuaries experiencing seagrass loss globally.

The Global Metabolome Profiles of Four Varieties of Lonicera caerulea, Established via Tandem Mass Spectrometry

Blue honeysuckle (Lonicera caerulea L.) bears dietary fruits that are rich in bioactive compounds. However, information on the metabolome profiles of honeysuckle varieties grown in Russia is limited. In this study, we employed tandem mass spectrometry to study the metabolome profiles of four L. caerulea varieties (Volhova, Tomichka, Goluboe vereteno, and Amfora) grown in two geographical locations in Russia, i.e., the Russian Far East and St. Petersburg. We observed that the metabolome profiles of the four varieties grown in two locations differ significantly, particularly in the polyphenol’s other compound classes. We were able to identify 122 bioactive compounds in extracts from honeysuckle berries, 75 compounds from the polyphenol group and 47 compounds from other chemical groups. Thirty chemical constituents from the polyphenol group (flavones jaceosidin, cirsiliol, sophoraisoflavone A, chrysoeriol-O-hexoside, flavonols dimethylquercetin-3-O-dehexoside, rhamnocitrin, rhamnetin II, stilbenes pinosylvin, resveratrol, dihydroresveratrol, etc.) and twenty-seven from other chemical groups were identified. The largest number of unique polyphenols is characteristic of the variety Tomichka, the selection of the regional state unitary enterprise “Bakcharskoye”, from the free pollination of L. caerulea, originating in the Primorsky Territory of Russia (L. caerulea subspecies Turczaninow). This genotype has the highest number of similar unique polyphenols, regardless of where it was grown. Blue honeysuckle genotypes originating from Primorsky Krai in Russia can be used in various breeding programs in order to improve and enrich the biochemical composition of fruits. It should also be noted that, regardless of the place of cultivation, the total amount of unique polyphenols remains quite large. Attention should be paid to the Volhova honeysuckle variety, obtained through gamma irradiation of the Pavlovskaya variety (Kamchatka ecotype). This sample is characterized by a stable composition of biologically active substances, regardless of the growing area. These data could support future research on the production of a variety of pharmaceutical products containing ultrapure extracts of L. caerulea.

Ключові засади та передові підходи забезпечення якості фітофармацевтичних препаратів

Due to the specificity of the composition and production of herbal medicines, ensuring their quality is particularly important, but at the same time an extremely difficult task. Purpose - to review the key problems, principles and aspects of the quality of herbal medicines and generalize advanced approaches to ensure their quality using the example of a phytoneering drug for the treatment of cough in acute bronchitis and inflammatory diseases of the respiratory tract. The concept of the quality of the phytoneering drug was considered and analyzed. The central role belongs to the well-founded choice of starting plant material, the use of cultivated subspecies of plants and own seed material, which is of critical importance for ensuring the optimal and stable phytochemical composition of the extracts. In addition, the quality of the phytoneering medicines is determined by strict compliance with the GACP guideline, a standardized production process in accordance with GMP using the latest patented technologies, leading procedures for continuous quality control and the possibility of analyzing the multicomponent composition of the obtained extracts. Thus, the concept of phytoneering provides a thorough and comprehensive methodological basis for establishing quality at each stage of the life cycle of the drug and the reproducibile and consistent quality of extracts from batch to batch. Together with a thorough evidence base of preclinical and clinical research all this is an absolute competitive advantage of the phytoneering medicine over other herbal drugs. No conflict of interests was declared by the authors.

Gut microbiome dynamics in index patients colonized with extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales after hospital discharge and their household contacts.

This study investigated the gut microbiome dynamics of index patients colonized with extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-Ec) (n = 5) or extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-Kp) (n = 3) and their household contacts (n = 9) up to 4 months after hospital discharge of the index patient using 16S rRNA amplicon gene sequencing. Samples were collected at the day of hospital discharge of the index patient, 1 week and 2 and 4 months after discharge. Compared to household contacts, we observed a significant lower alpha diversity (P < 0.001) among index patients and significant (P < 0.05) separation between the two groups for beta diversity. Principal component analysis of the samples from each household (i.e., index patient and respective household contact) showed a clear shift in microbiome composition, in 4/8 index patients, from dissimilar to more similar to the household contact group. This suggests recovery of the microbiome to a healthier status, which was also reflected by de novo colonization of (health-associated) taxa. In contrast, the four time-point samples of the household contacts clustered together indicating a stable microbiome composition over time irrespective of low-level ESBL-Ec (n = 3) or ESBL-Kp (n = 2) colonization. In conclusion, here we show that, at the day of hospital discharge, the microbiome composition of index patients is dissimilar from that of household contacts. Over time, signals of microbiome recovery were observed in half of the index patients. The stable microbiome composition in household contacts irrespective of low-level ESBL-Ec or ESBL-Kp colonization suggests that the gut microbiome in these healthy people provided colonization resistance against ESBL-PE outgrowth. IMPORTANCE Colonization with extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-PE) often precedes infections and is therefore considered as a great threat for public health. Here, we studied the gut microbiome dynamics in eight index patients colonized with ESBL-PE after hospital discharge and the impact of exposure to this index patient on the gut microbiome dynamics of their household contacts. We showed that the microbiome composition from index patients is different from their household contacts upon hospital discharge and that, in some of the index patients, their microbiome composition over time shifted toward the composition of their household contacts. In contrast, household contacts showed a stable microbiome composition over time irrespective of low-level extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-Ec) or extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-Kp) gut colonization, suggesting that, in healthy microbiomes, colonization resistance is able to prevent ESBL-PE expansion.

Prediction of thermodynamic stability of actinide compounds by machine learning model

The thermodynamic phase stability plays a crucial role as it serves as a fundamental parameter governing the synthesizability of materials and their potential for degradation under specific operating conditions. In this study, two machine learning (ML) models, random forest (RF) and neural network (NN), were used to predict the thermodynamic phase stability of actinide compounds using a dataset consisting of 62204 DFT-calculated energies. Our study utilizes a comprehensive range of properties that do not contain structural information, making them applicable to materials composed of any number of constituent elements. Notably, the trained models achieve an approximation that closely aligns with the error obtained from DFT calculations, while drastically reducing computational time by several orders of magnitude. Moreover, we extended our analysis to predict binary phase diagrams of Generation IV nuclear fuels using the trained models. To address the limitations of a single model for predicting certain compounds and enhance model robustness, a simple ensemble learning approach, i.e., the multi-component learner was employed. By synergistically combining prediction outcomes from RF and NN models, the ensemble learning approach excels in accurately predicting phase diagrams of actinide compounds. Utilizing the compound components forecasted by the model as a foundation, we embarked on an extensive series of structural searches and conducted thorough phonon dispersion studies. The outcomes unequivocally affirm the model's efficacy in accurately predicting stable compound compositions.

Hydrothermal extraction and physicochemical characterization of biogenic hydroxyapatite nanoparticles from buffalo waste bones for in vivo xenograft in experimental rats

Hydroxyapatite (HA) can be used in odontology and orthopedic grafts to restore damaged bone due to its stable chemical characteristics, composition, and crystal structural affinity for human bone. A three-step hydrothermal method was used for the extraction of biogenic calcined HA from the buffalo waste bones at 700 °C (HA-700) and 1000 °C (HA-1000). Extracts were analyzed by thermogravimetric analysis, differential scanning calorimetry, X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and in vivo examination of HA xenografts for femoral lesions in experimental rats. Crystallinity, purity, and morphology patterns showed that the HA main phase purity was 84.68% for HA-700 and 88.99% for HA-1000. Spherical HA nanoparticles were present for calcined HA-700 samples in the range 57–423 nm. Rats with critical bone lesions of 3 mm in diameter in the left femur treated with calcined HA-700 nanoparticles healed significantly (p < 0.001) faster than rats treated with HA-1000 or negative controls. These findings showed that spherical biogenic HA-700 NPs with a bud-like structure have the potential to stimulate both osteoconduction and bone remodeling, leading to greater bone formation potential in vivo. Thus, the calcined biogenic HA generated from buffalo waste bones may be a practical tool for biomedical applications.

3D In2S3/C/Fe3C nanofibers for Z-scheme photocatalytic CO2 conversion to acetate

Constructing a Z-scheme heterostructure is of great significance to achieve efficient photocatalytic CO2 conversion without sacrificial reagents. However, the fabrication of a well-suited Z-scheme remains a challenge. In this work, we constructed a Z-scheme system with a suitable band structure by in-situ hydrothermal growth of In2S3 nanosheets on electrospun Fe3C/Carbon fibers with 3D structure. The Z-scheme electron transport path is verified by the calculation of the energy band structure calculation and the method of photodeposition, indicating that In2S3 and Fe3C are reduction reaction sites and oxidation reaction sites respectively. Carbon fibers serve as both the skeleton of the 3D structure and the electron mediator from Fe3C to In2S3. Moreover, the DFT calculation demonstrates that the introduction of Fe3C can reduce the energy barrier of *CO and *COH coupling on In2S3, and weaken the bonding of In-S, thereby enhancing the product selectivity towards acetate. Owing to the efficient charge transfer of the Z-scheme system, the photocorrosion in In2S3 is also greatly reduced, showing a relatively stable chemical composition after several hours of reaction. Compared with In2S3 and Fe3C/C, In2S3-C/Fe3C composites showed a significantly increased acetate evolution rate of 11.33 μmol/h/g without any sacrificial reagents. This work provides important insights into the design and research of the photocatalyst system that combines a monolithic 3D structure and a Z-scheme charge flow for efficient CO2 conversion.

A Transition-Matrix Growth Model and Equilibrium Curve for Natural Forests in Jiangxi Province

Researchers build growth models to predict the growth of forest stands and propose management measures to improve the overall quality of these stands. In this study, data collected from 91 sample plots from the eighth (2010) and ninth (2015) Chinese National Forest Inventories in Jiangxi Province were used to establish a transition-matrix growth model. Then, 12 potential equilibrium curves were set to guide forest management, and a transition-matrix growth model was used to predict stand growth in Jiangxi Province. In each 10-year management period, trees with diameters that exceeded the equilibrium curve were cut down. The results show that species diversity (H1), size diversity (H2), and basal area (B) have statistically significant influences on growth, mortality, and recruitment. Moreover, the high accuracy of the transition-matrix growth model is demonstrated. According to the simulation results, B = 35 m2/ha, the maximum diameter of retained trees Dmax = 45 cm and the adjacent diameter ratio q = 1.7 constitute the optimal equilibrium curve to guide forest management. The diameter distribution guided by the equilibrium curve is reverse J-shaped and is associated with significant increases in the hardwood stock volume and current annual growth. Under the guidance of the equilibrium curve, the forests in Jiangxi Province can be reasonably managed, produce more high-economic-value timber, and achieve a more stable species composition. This study will help maximize the ecological and economic benefits of forests and provide a reference for the realization of the sustainable development of forestry. Furthermore, the results can be used to improve the facility and accuracy of natural forest harvesting.

Moisture‐Insensitive, Phase‐Stable Indium‐Based Metal Halides and Their Light‐Emitting Applications

AbstractTernary indium (In)‐based metal halides are gaining increased attention as promising lead (Pb)‐free alternatives for light‐emitting diodes (LEDs) owing to their broadband emission and high photoluminescence quantum yields (PLQYs). However, most of the pure In‐based compositions suffer from instability against moisture and thermal stress, leading to a rapid degradation of material and hence their optical properties. Herein, a new kind of organic–inorganic hybrid In‐based metal halide BA6InCl9 (BA+ = C4H11N+) is presented, which exhibits stable crystal structure and material composition at both ambient (over 5 months) and heating conditions (up to 200 °C). Besides, the Huang‐Rhys factor of ≈4.94 determined for BA6InCl9 is considerably smaller than most Pb‐free perovskites, which suggests a relatively weak exciton‐phonon coupling in these crystals. By trace amounts of antimony (III) (Sb3+) doping, the PLQY of the BA6InCl9 single crystals can be markedly improved from ≈25% to 95%, and the ensuing down‐conversion LEDs exhibit bright orange‐red emission with an external quantum efficiency of 0.12%, which retains ≈50% of the initial luminance after 380 min of continuous operation in ambient air. It is forseen that the study will prompt future research on In‐based metal halides and their use in stable light‐emitting applications.

Двухуровневый цифровой экологический мониторинг городов горно-металлургического комплекса Урала

Introduction. The main approach to the development of modern cities is an approach based on the balance of social, economic, and environmental subsystems, within the framework of which plans to achieve sustainable growth are implemented. In the era of digitalization, the most important condition for effective environmental management is the use of advanced tools for analyzing data obtained during the environmental monitoring procedure. Materials and methods. The methodology for monitoring the state of various components of the environment involves a number of sequential operations. The first stage of the study (obtaining a priori information) pursues the goal of creating a landscape-geochemical basis on which information about typical elementary landscapes reflecting the structure of the area is placed. The second stage includes obtaining operational information about the state of selected environmental components using field and laboratory methods. At the third stage, desk processing of information is carried out. Results. The structure of environmental monitoring can be divided into levels in accordance with the degree of detail of the tasks assigned to it. The most appropriate division of environmental monitoring in cities for the conditions of the Urals seems to be the following levels: a) local, examining the state of the environment as a whole in the city or on the border of the sanitary protection zone of an enterprise and b) detailed, examining the state of the environment from the impact of waste disposal facilities. Discussion. In the field of environmental monitoring, a digital database should be created at the local and detailed levels, with the help of which it is possible to conduct analysis and further forecast the state of the environment, with the subsequent development of environmental measures. Environmental monitoring within cities with a mining and metallurgical complex must be carried out comprehensively, including the atmosphere, surface water, soil, snow cover, groundwater and vegetation. Conclusion. Thus, the proposed environmental monitoring system is characterized by high environmental and economic efficiency, which meets the requirements of sustainable development at the present stage. Resume. For the cities of the mining and metallurgical complex of the Urals, it is necessary to conduct two-level environmental monitoring with the development, implementation and dissemination of digital technologies in the environmental sphere. Environmental monitoring within cities with a mining and metallurgical complex must be carried out comprehensively, including the atmosphere, surface water, soil, snow cover, groundwater and vegetation. Conducting local monitoring in the territory of influence of the enterprise and detailed monitoring in the zone of influence of waste disposal facilities presupposes the presence of stable observations in the space-time interval and a stable ingredient composition. The instability of observations leads to deterioration of the analysis, which reduces the quality of the forecast of the situation and recommendations for preventive measures. Suggestions for practical applications and directions for future research. The research results can be useful in the formation of a data bank on the state of the environment for the development and adoption of environmental measures with high environmental and economic efficiency at industrial facilities of the mining and metallurgical complex.