Variation In Composition Research Articles

Study of the Influence of Coating Roughness on the Properties and Wear Resistance of Electrospark Deposited Ti6Al4V Titanium Alloy

The present work is concerned with studying surface parameters of coatings deposited to titanium alloy Ti6Al4V by electrospark deposition (ESD) with hard alloy depositing electrodes based on WC, TiC and TiCN. The variation of roughness parameters, composition, structure and tribological characteristics of coatings as a function of ESD mode parameters was investigated. The influence of the mode parameters on the main coating roughness parameters (Ra, Rz, Rmax, Rpk, Rk, Rs, Rsk, Rku (ISO 21920-2:2021) was analysed, the values of which can be used to determine the load bearing capacity and wear resistance. The results of the tribological tests showed that within the test range, the roughness of the coatings has a controversial influence on their frictional wear performance. As the roughness parameters increase to Ra=3÷3.5 µm, the relative wear resistance of the coated surfaces also increases, reaching values up to 4÷5 µm for the electrodes used and no significant changes in the wear mechanism were observed. However, increasing coating roughness above Ra=3.5 to 5 µm results in a monotonic decrease in relative wear resistance to 2.5÷3 times. Possible ways to reduce the surface roughness and increase the wear resistance of coatings were presented.

Employment, labor productivity and environmental sustainability: Firm‐level evidence from transition economies

AbstractThis article investigates the impact of investment in environmentally sustainable practices on employment and labor productivity growth in transition economies. It explores the influence of labor skill composition and geographical variations on sustainability dynamics. Utilizing data from the World Bank's Enterprise Survey 2019 across 24 transition economies, an environmental sustainability index is constructed using Principal Components Analysis. To address endogeneity concerns, a combination of fixed effects and instrumental variables is employed. The findings highlight the significance of environmental sustainability for both employment and labor productivity growth. However, the observed relationships diminish in significance when comprehensively addressing endogeneity, suggesting a more nuanced and time‐dependent connection between environmentally sustainable practices and job growth. Notably, high‐skill firms experience a deceleration in job creation following sustainability investments, while low‐skill firms benefit from improved labor productivity. Geographically, Central Europe exhibits more pronounced impacts on labor productivity, potentially attributed to higher levels of development and sustainability awareness compared to Southeast Europe and the Commonwealth of Independent States.

Synthesis and Characterization of Activated Carbon/Alginate-Fe Composites as Slow Release Fertilizer

Research on the slow release kinetics of Fe(III) ions from Activated Carbon/Alginate-Fe(III) composites or abbreviated as K/A-Fe(III) has been carried out. The aim of this research was to synthesize K/A-Fe(III) composite as a material that has the potential to become a slow release micronutrient fertilizer and to study the kinetics of slow release of Fe(III) ions from the composite. The K/A-Fe(III) composite was synthesized by mixing alginate suspension and activated carbon (alginate: activated carbon weight ratio = 1:3 and 3:1) until homogeneous. Composite grains were characterized using Fourier Transformed Infrared (FTIR) spectroscopy, the kinetics of Fe(III) release from the three composite variations found that KAlg31 composite showed more absorption and release of Fe ions than KAlg13.

Gamma-enhancement of reflected light images as a routine method for assessment of compositional heterogeneity in common low-reflectance Fe-bearing minerals

Abstract Incorporation of impurity elements into minerals impacts on their physical properties (e.g., reflectance, hardness, and electrical conductivity) but the quantitative relationships between these features and compositional variation remain inadequately constrained. Prior work has shown that gamma-enhancement of reflected light images represents a simple yet powerful tool to assess the compositional heterogeneity of single pyrite crystals as it can enhance subtle differences in reflectance between distinct domains with different minor element concentrations. This study extends the gamma correction method to several other common Fe-bearing minerals, magnetite, garnet, wolframite, and tetrahedrite-tennantite, which all have far lower reflectance than pyrite. Gamma-enhanced optical images reveal clear variations in reflectance that are either systematic with increased minor element concentration as the change in gray value on backscatter electron (BSE) images (in the case of magnetite, garnet, and tetrahedrite-tennantite) or contrasting (as in pyrite), yielding a convincing linkage between reflectance variation and compositional heterogeneity. Reflectance variation is an expression of the distribution of the average effective number of free electrons on the mineral surface that can re-emit light when excited by visible light. Gamma-enhanced images can reveal compositional heterogeneity in minerals such as wolframite where small atomic mass differences between substituting elements (Mn and Fe, in the case of wolframite) are virtually impossible to observe as a variation of gray values on BSE images. Results also demonstrate that Fe-rich domains in these minerals can be expected to have higher reflectance than Fe-poor domains whenever Fe is a major constituent. The greater reflectance is attributed to Fe ions having a greater effective number of free electrons than many other elements (e.g., Co, Ni, Si, Ca, Al, Mg, Mn, and As). The research highlights the utility of gamma correction as an inexpensive tool for routine evaluation of compositional heterogeneity in common Fe-bearing minerals, potentially obviating the necessity of a microbeam platform to correlate textures and composition.

Seasonality and longer-term development generate temporal dynamics in the Populus microbiome.

Temporal variation in community composition is central to our understanding of the assembly and functioning of microbial communities, yet the controls over temporal dynamics for microbiomes of long-lived plants, such as trees, remain unclear. Temporal variation in tree microbiomes could arise primarily from seasonal (i.e., intra-annual) fluctuations in community composition or from longer-term changes across years as host plants age. To test these alternatives, we experimentally isolated temporal variation in plant microbiome composition using a common garden and clonally propagated plants, and we used amplicon sequencing to characterize bacterial/archaeal and fungal communities in the leaf endosphere, root endosphere, and rhizosphere of two Populus spp. over four seasons across two consecutive years. Microbial community composition differed among seasons and years (which accounted for up to 21% of the variation in microbial community composition) and was correlated with seasonal dissimilarity in climatic conditions. However, microbial community dissimilarity was also positively correlated with time, reflecting longer-term compositional shifts as host trees aged. Together, our findings demonstrate that temporal patterns in tree microbiomes arise from both seasonal fluctuations and longer-term changes, which interact to generate unique seasonal patterns each year. In addition to shedding light on two important controls over the assembly of plant microbiomes, our results also suggest future studies of tree microbiomes should account for background temporal dynamics when testing the drivers of spatial patterns in microbial community composition and temporal responses of plant microbiomes to environmental change.IMPORTANCEMicrobiomes are integral to the health of host plants, but we have a limited understanding of the factors that control how the composition of plant microbiomes changes over time. Especially little is known about the microbiome of long-lived trees, relative to annual and non-woody plants. We tested how tree microbiomes changed between seasons and years in poplar (genus Populus), which are widespread and ecologically important tree species that also serve as important biofuel feedstocks. We found the composition of bacterial, archaeal, and fungal communities differed among seasons, but these seasonal differences depended on year. This dependence was driven by longer-term changes in microbial composition as host trees developed across consecutive years. Our findings suggest that temporal variation in tree microbiomes is driven by both seasonal fluctuations and longer-term (i.e., multiyear) development.

Dental Solid Waste Analysis: A Scoping Review and Research Model Proposal

In the face of 21st-century environmental challenges, including climate change, migration pressures, and waste disposal issues, certain healthcare sectors, notably dentistry, pose a significant global environmental footprint with concerns about carbon emissions and waste production. This scoping review searches the paradox that healthcare, while dedicated to safeguarding health, inadvertently contributes to environmental degradation through waste accumulation and disposal. The analysis of the relevant literature emphasizes the imperative for an environmentally sustainable approach to dental waste measurement, disposal methods, and comprehensive education for stakeholders. Aligned with the World Conference on Sustainable Development and the United Nations’ 2030 Agenda, the study adhered to PRISMA-ScR systematic review guidelines and the Institute of Medicine’s recommendations. The study utilized Medline/PubMed and international organization websites for data retrieval, employing Boolean operator queries in Medline. The systematic literature analysis identified six cross-sectional studies (2004–2023) highlighting variations in dental waste composition due to the lack of standardized identification methods. This heterogeneity underscores the need for a proposed research model, emphasizing comprehensive methodologies and healthcare staff training in waste management, thus transforming the analysis into a scoping review. The study advocates for environmentally conscious dental practices, contributing to broader sustainable healthcare goals through sharing of a research protocol for dental solid waste management.

Effect of microcarbon particle size and dispersion on the electrical conductivity of LLDPE-carbon composite

This experimental research aimed to develop a conductive polymer composite (CPC) material for electromechanical devices. The composite was made by incorporating conductive micro carbon derived from rice husks into a Linear Low-Density Polyethylene (LLDPE) polymer matrix using hot compaction. Variations of filler composition were used, with carbon loading of 50%, 45%, and 40%, and mesh sizes of #150, #200, and #250. The experimental results showed that particle size variations did not significantly affect composite density, but higher mesh selection improved filler dispersion within the matrix, resulting in higher electrical conductivity values. The optimal conductivity value of 9.43E-04 S/cm was achieved with a micro-carbon composition of 50% loading. However, decreasing micro carbon loading had a more significant impact on reducing electrical conductivity values.

Nutritional Analysis of Three Commercially Important Dried Fish (Otolithoides Pama, Trichiurus Haumela, Harpodon Nehereus) of Three Different Countries

The study aimed to compare the nutritional and fatty acid composition of three dried fish species, Otolithoides pama, Trichiurus haumela, and Harpodon nehereus, of Bangladesh and imported sample of India and Myanmar. Proximate compositions were analyzed using the AOAC method with modifications, and fatty acid analyses were conducted via Gas Chromatography Mass Spectrometry (GCMS). Overall, the quality of fish samples from all three countries was deemed excellent. The dried Harpodon nehereus from Myanmar stood out with the highest protein content (62.81±2.83%) among the species, while also exhibiting the highest lipid content (11.03±0.39%). Indian Harpodon nehereus had the highest ash content (10.18±0.72%), and Bangladesh’s dried Harpodon nehereus had higher moisture and fiber content. For Trichiurus haumela, the Bangladeshi sample had the highest protein and lipid content, whereas Myanmar’s sample had the highest ash concentration. Moisture and fiber content were higher in Myanmar and Bangladesh. Otolithoides pama displayed variations in protein, ash, moisture, and fiber content across countries, with India having the highest moisture content. The major fatty acids identified included Methyl Palmitate, Methyl Palmitpleate, Methyl Laurate, Methyl Arachidonate, and Methyl Stearate, with notable levels of Methyl Linoleate in all three species, particularly in Bangladeshi Trichiurus haumela. In summary, the study revealed significant compositional variations in dried fish from different countries.

Beyond salinity: Plants show divergent responses to soil ion composition

AbstractAimIn salt‐affected environments, salinity shapes ecosystem functions and species composition. Apart from salinity, however, we know little about how soil chemical factors affect plant species. We hypothesized that specific ions, most of which contribute to salinity, co‐determine plant niche differentiation. We asked if the importance of ions differs for species with (halophytes) and without (associated species) physiological adaptations to saline soils.LocationCarpatho‐Pannonian region (Central and Eastern Europe).Time period2005–2021.Major taxa studiedVascular plants.MethodsWe recorded species occurrences and collected soil samples in 433 plots in saline habitats. We measured pH, salinity (electrical conductivity), and concentrations of Ca2+, K+, Mg2+, Na+, SO42− Cl−, CO32− and mineral nitrogen (mN) and calculated the sodium adsorption ratio (SAR). For 88 species, we fitted response curves with Huisman–Olff–Fresco (HOF) models. To study ions' effects on species composition and ions' variance, we compared unconstrained and constrained ordinations and performed a principal component analysis. We used random forests to analyse the importance of ions for individual species and created two‐dimensional species niche plots for key ions.ResultsIon concentration niches varied among species and did not necessarily correspond to soil salinity or alkalinity. We frequently observed monotonic, sigmoidal model responses, while skewed unimodal responses were rare. Ions explained a considerable proportion of species compositional variation. Particularly, Na+, SO42−, Cl−, and CO32− contributed to the ions' variance. Na+, followed by SO42−, Cl−, CO32−, Ca2+, Mg2+, and mN, was most important for the occurrence of individual species. Compared to associated species, Na+, SO42−, and mN were significantly less important for halophytes, whereas Cl− and CO32− played a significant role.Main conclusionsWe show that ion composition co‐determines niche differentiation in saline soils, suggesting evolved physiological adaptations in halophytes. Our study calls for incorporating high‐resolution data on soil ion composition in ecological research.

Variation in chemical composition and volatility of oxygenated organic aerosol in different rural, urban, and mountain environments

Abstract. The apparent volatility of atmospheric organic aerosol (OA) particles is determined by their chemical composition and environmental conditions (e.g., ambient temperature). A quantitative, experimental assessment of volatility and the respective importance of these two factors remains challenging, especially in ambient measurements. We present molecular composition and volatility of oxygenated OA (OOA) particles in different rural, urban, and mountain environments (including Chacaltaya, Bolivia; Alabama, US; Hyytiälä, Finland; Stuttgart and Karlsruhe, Germany; and Delhi, India) based on deployments of a filter inlet for gases and aerosols coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (FIGAERO-CIMS). We find on average larger carbon numbers (nC​​​​​​​) and lower oxygen-to-carbon (O : C) ratios at the urban sites (nC: 9.8 ± 0.7; O : C: 0.76 ± 0.03; average ±1 standard deviation) compared to the rural (nC: 8.8 ± 0.6; O : C: 0.80 ± 0.05) and mountain stations (nC: 8.1 ± 0.8; O : C: 0.91 ± 0.07), indicative of different emission sources and chemistry. Compounds containing only carbon, hydrogen, and oxygen atoms (CHO) contribute the most to the total OOA mass at the rural sites (79.9 ± 5.2 %), in accordance with their proximity to forested areas (66.2 ± 5.5 % at the mountain sites and 72.6 ± 4.3 % at the urban sites). The largest contribution of nitrogen-containing compounds (CHON) is found at the urban stations (27.1 ± 4.3 %), consistent with their higher NOx levels. Moreover, we parametrize OOA volatility (saturation mass concentrations, Csat) using molecular composition information and compare it with the bulk apparent volatility derived from thermal desorption of the OOA particles within the FIGAERO. We find differences in Csat values of up to ∼ 3 orders of magnitude and variation in thermal desorption profiles (thermograms) across different locations and systems. From our study, we draw the general conclusion that environmental conditions (e.g., ambient temperature) do not directly affect OOA apparent volatility but rather indirectly by influencing the sources and chemistry of the environment and thus the chemical composition. The comprehensive dataset provides results that show the complex thermodynamics and chemistry of OOA and their changes during its lifetime in the atmosphere. We conclude that generally the chemical description of OOA suffices to predict its apparent volatility, at least qualitatively. Our study thus provides new insights that will help guide choices of, e.g., descriptions of OOA volatility in different model frameworks such as air quality models and cloud parcel models.

Evaluation of venom diversity and antivenom quality from the venom of long-term captive vs recently wild captured Pseudocerastes persicus snake: An In vitro and In vivo study

Snakebite envenomation is a life-threatening condition and antivenoms are used as the most effective treatment. Venom obtained from snakes in long-term captivity showed some variations in comparison to the venom of the wild snakes. The objective of this study is to compare the venom of the Pseudocerastes persicus under long-term captivity and wild conditions as well as the antivenom obtained from these venoms. We have analyzed venom samples and produced trivalent antivenoms using the venom of long-term captive (LTC) or recently wild-captured (RWC) Pseudocerastes persicus, and RWC Macrovipera lebetina, and Echis carinatus. The HPLC analysis revealed that the RWC snakes' venom had three peaks that were not present in the LTC snake's venom. Further analysis using MALDI-TOF and MS/MS showed that the fraction with a retention time (RT) of 14 min contained a toxin from the Kunitz-type serine protease inhibitor (KUT) class, while the fraction with RT 21 a peptide identified within the snake venom metalloproteinase (SVMP) class. The third peak was identified as a sphingolipid.Interestingly, the in vivo preclinical tests showed no significant differences in the effectiveness of the antivenoms. which could be due to the cross-immunogenicity or cross-reactivity between different toxins in the venom. According to our results, small variations in the venom composition of a species do not lead to a decrease in the efficacy of the polyvalent antivenom.

Targeted and untargeted metabolomics reveals meat quality in grazing yak during different phenology periods on the Qinghai-Tibetan Plateau

Yak meat is more popular among consumers because of its high nutritional value, but little attention has been paid to its meat quality, which is affected by different phenology periods grass. We hypothesized that seasonal variations in grass composition influenced the ruminal bacteria community, and eventually affected the meat quality of yaks. This study aims to investigate the relationship of meat quality in grazing yak as well as the key rumen bacteria using targeted and untargeted metabolomics and 16S rRNA during different phenology periods. The main three altered metabolic pathways in grazing yak, including amino acids biosynthesis, glutathione metabolism, and fatty acids biosynthesis, were found in the grass period (GP) group compared to the regreen period (RP) and hay period (HP) groups. The GP group had higher concentrations of flavor amino acids (FAA), polyunsaturated fatty acids (PUFA), and a lower ratio of n-6/n-3 compared with the RP group. Correlation analysis results showed that Rikenellaceae_RC9_gut_group was positively correlated with fatty acids and lipid metabolites, which might be involved in lipid metabolism. Pediococcus had a positive correlation with biological peptides, which could be involved in the metabolism of bioactive compounds. In conclusion, grass in different phenology periods was associated with modified amino acids and fatty acids composition of yak meat as well as altered regulation of biological pathways, which was correlated with changes in rumen bacterial communities.

A multi-proxy detrital study from Permian-Triassic fluvial sequences of Victoria Land (Antarctica): Implications for the Gondwanan basin evolution

One of the most complete Permian-Triassic fluvial sequences of the Beacon Supergroup, characterizing the infilling of the Transantarctic Basin, is recorded in the Allan Hills in Victoria Land (Antarctica). The multidisciplinary provenance approach carried out in this study includes UPb analysis on detrital zircons, chemistry on detrital mineral phases (garnet and white mica), and sandstone petrography. These, coupled with the data regarding the stratigraphic/sedimentological framework, provide a reconstruction of the geological history of the Permian-Triassic portion of the Beacon Supergroup, showing shifting clastic provenance from different source rocks. Results obtained from this integrated study support a source for the Permian Weller Coal Measures from the local basement, made up of very low- to high grade metamorphic rocks. A compositional shift is recorded with the Lower Triassic Feather Conglomerate, mainly linked with changes in the fluvial style, likely associated with tectonic activity. The Middle to Upper Triassic Lashly Formation shows the main provenance change, supporting a distal source region: the fluvial system received a volcanoclastic input derived from the Permian-Triassic arc located to the east of the basin. The compositional and provenance variations, together with paleocurrent indicators, compared to the coeval units in the central Transantarctic Mountains, allow the reconstruction of the basin evolution and of the changing clastic drainage patterns. Data support the occurrence of articulated sub-basins where alluvial sedimentation settled, in which a morphological-structural divide was represented by the Ross High, separating during the Permian up to the Early Triassic the Victoria Land sub-basin from the main Transantarctic Basin. According to the changed composition of the Lashly Formation sandstones, it appears that in the Middle/Late Triassic, the Ross High was not more a morphological barrier, and that the Victoria Land sub-basin was joined with the Transantarctic foreland Basin.

Variable carbon isotope fractionation of photosynthetic communities over depth in an open-ocean euphotic zone

Marine particulate organic carbon (POC) contributes to carbon export, food webs, and sediments, but uncertainties remain in its origins. Globally, variations in stable carbon isotope ratios (δ13C values) of POC between the upper and lower euphotic zones (LEZ) indicate either varying aspects of photosynthetic communities or degradative alteration of POC. During summertime in the subtropical north Atlantic Ocean, we find that δ13C values of the photosynthetic product phytol decreased by 6.3‰ and photosynthetic carbon isotope fractionation (εp) increased by 5.6‰ between the surface and the LEZ-variation as large as that found in the geologic record during major carbon cycle perturbations, but here reflecting vertical variation in δ13C values of photosynthetic communities. We find that simultaneous variations in light intensity and phytoplankton community composition over depth may be important factors not fully accounted for in common models of photosynthetic carbon isotope fractionation. Using additional isotopic and cell count data, we estimate that photosynthetic and non-photosynthetic material (heterotrophs or detritus) contribute relatively constant proportions of POC throughout the euphotic zone but are isotopically more distinct in the LEZ. As a result, the large vertical differences in εp result in significant, but smaller, differences in the δ13C values of total POC across the same depths (2.7‰). Vertical structuring of photosynthetic communities and export potential from the LEZ may vary across current and past ocean ecosystems; thus, LEZ photosynthesis may influence the exported and/or sedimentary δ13C values of both phytol and total organic carbon and affect interpretations of εp over geologic time.

Molecular mechanisms of chaperone-directed protein folding: Insights from atomistic simulations.

Molecular chaperones, a family of proteins of which Hsp90 and Hsp70 are integral members, form an essential machinery to maintain healthy proteomes by controlling the folding and activation of a plethora of substrate client proteins. This is achieved through cycles in which Hsp90 and Hsp70, regulated by task-specific co-chaperones, process ATP and become part of a complex network that undergoes extensive compositional and conformational variations. Despite impressive advances in structural knowledge, the mechanisms that regulate the dynamics of functional assemblies, their response to nucleotides, and their relevance for client remodeling are still elusive. Here, we focus on the glucocorticoid receptor (GR):Hsp90:Hsp70:co-chaperone Hop client-loading and the GR:Hsp90:co-chaperone p23 client-maturation complexes, key assemblies in the folding cycle of glucocorticoid receptor (GR), a client strictly dependent upon Hsp90/Hsp70 for activity. Using a combination of molecular dynamics simulation approaches, we unveil with unprecedented detail the mechanisms that underpin function in these chaperone machineries. Specifically, we dissect the processes by which the nucleotide-encoded message is relayed to the client and how the distinct partners of the assemblies cooperate to (pre)organize partially folded GR during Loading and Maturation. We show how different ligand states determine distinct dynamic profiles for the functional interfaces defining the interactions in the complexes and modulate their overall flexibility to facilitate progress along the chaperone cycle. Finally, we also show that the GR regions engaged by the chaperone machinery display peculiar energetic signatures in the folded state, which enhance the probability of partial unfolding fluctuations. From these results, we propose a model where a dynamic cross-talk emerges between the chaperone dynamics states and remodeling of client-interacting regions. This factor, coupled to the highly dynamic nature of the assemblies and the conformational heterogeneity of their interactions, provides the basis for regulating the functions of distinct assemblies during the chaperoning cycle.

The role of gravity and temperature on hydrogen-containing mixtures in the subsurface

A model for thermal and gravity-induced compositional grading of hydrogen-containing gas mixtures using a cubic equation of state is presented. The theoretical background of compositional gradient modeling is reviewed, and the implementation of a thermal gradient model is used to predict the compositional variation of a hydrogen-natural gas mixture for both depleted gas reservoir and salt cavern applications. We show that near-uniform gas composition versus depth is expected during the storage of hydrogen mixed with natural gas over 100 m of vertical relief. Further study into the calculation and significance of the ideal portion of the component molar enthalpy is needed to increase confidence in model implementation and application.

Consistency and Variability of the Human Milk Oligosaccharide Profile in Repeat Pregnancies.

Human milk oligosaccharides (HMOs) are a set of complex carbohydrates and the third largest solid component of human milk, after lactose and lipids. To date, over 150 HMOs have been identified and the diversity of structures produced by lactating women is influenced by maternal genetics as well as other maternal, infant, and environmental factors. While the concentrations of individual HMOs have been shown to vary between individuals and throughout the course of lactation, the variability of HMO concentration profiles following different pregnancies occurring in the same woman is presently unknown. As such, the objective of this study was to compare HMO concentrations in human milk samples provided by the same women (n = 34) following repeat pregnancies. We leveraged existing human milk samples and metadata from the UC San Diego Human Milk Research Biorepository (HMB) and measured the concentrations of the 19 most abundant HMOs using high-performance liquid chromatography with fluorescence detection (HPLC-FL). By assessing dissimilarities in HMO concentration profiles, as well as concentration trends in individual structures between pregnancies of each participant, we discovered that HMO profiles largely follow a highly personalized and predictable trajectory following different pregnancies irrespective of non-genetic influences. In conclusion, this is the first study to assess the interactions between parity and time following delivery on variations in HMO compositions.

Advancements and environmental considerations in portland cement-based radiation shielding concrete: Materials, properties, and applications in nuclear power plants– review

Radiation Shielding Concrete plays a critical role in safeguarding against ionizing radiation, in nuclear power plants, medical facilities, and other radiation-sensitive environments. This review paper presents a comprehensive examination of radiation shielding concrete development, highlighting a novel approach that incorporates a diverse range of natural and industrial materials. Traditional radiation shielding concrete formulations rely heavily on virgin materials, contributing to environmental degradation and resource depletion. In contrast, this paper explores the innovative use of natural materials, industrial by-products, and waste materials, emphasizing the environmental sustainability and resource efficiency of such approaches. By harnessing these alternative materials, the paper outlines how radiation shielding concrete production can significantly reduce its ecological footprint while maintaining or even enhancing its radiation shielding capabilities. The paper delves into the functional aspects, composition variations, and performance characteristics of radiation shielding concrete, providing a holistic perspective on the diverse materials employed. Additionally, it thoroughly examines the factors influencing the effectiveness of radiation shielding concrete in nuclear power plants. Furthermore, this review discusses recent developments and advancements in radiation shielding concrete, offering insights into the cutting-edge research and innovations that are shaping the future of radiation shielding. The integration of natural and industrial materials presents promising avenues for enhancing the versatility, cost-effectiveness, and sustainability of radiation shielding concrete.

A ToF-SIMS methodology for analyzing inter-tissue lipid distribution variations and intra-tissue multilevel mass spectrometry imaging within a single rat

A comprehensive investigation of lipid distribution across various tissues is significant in elucidating their physiological roles and the development of associated metabolic disorders. In this work, high spatial-resolved ToF-SIMS was employed to compare and analyze lipid characteristics in brain, liver, heart and kidney tissues obtained from a single rat. Notably, various lipids including phosphatidylcholine, cholesterol, fatty acids, and vitamin E exhibited distinct distribution patterns among these tissues. Furthermore, the metabolic characteristics within a given tissue were acquired at the tissue and sub-tissue to cellular level, thus establishing a connection with their biological functionalities. These findings demonstrate the capability of ToF-SIMS to discern variations in metabolite composition across distinct tissues, as well as to monitor the progression of metabolite spatial distribution within the same tissues. Such insights hold potential for investigating metabolic alterations in inter-tissue or intra-tissue contexts following drug intervention or metabolic disorders, thereby elucidating the underlying metabolic mechanisms of diseases and identifying novel metabolic pathways for therapeutic interventions.

Characteristics of high-order silane based Si and SiGe epitaxial growth under 600 ℃

Low temperature Si and SiGe epitaxy have been crucial in the semiconductor industry, prompting interest in high-order silanes as Si precursors. In this study, we investigated the growth characteristics of Si and SiGe epitaxial layers using Si2H6, Si3H8, and Si4H10 precursors by ultra-high vacuum chemical vapor deposition at temperatures between 500℃ and 600 ℃. We examined the effects of each precursor on the growth behaviors through varying temperature and flow rate conditions. For these three precursors, activation energies for Si epitaxy were measured to be below surface H desorption energy, and an increase in the order led to a greater adatom density at equivalent flow rates. In SiGe epitaxy, we observed Ge composition variations with temperature at each Ge-to-Si flow ratio depending on the Si precursors. Si2H6 exhibited almost consistent Ge compositions across temperatures, and the activation energy for SiGe epitaxy was decreased to 1.73 eV when the flow ratio was increased to 1. In comparison, Si3H8 and Si4H10 exhibited negligible changes in Ge compositions for the flow ratios below 0.5, with activation energies of 1.88 and 1.62 eV, respectively. Based on our experimental results, we proposed potential reaction pathways for high-order silane precursors.