Composition Of Aggregates Research Articles

Impact of tourist and recreational activities on the indicators of soil-ecological monitoring of the adjacent territory of Lake Teletskoe (Altai Mountains)

Relevance. The increasing recreational load on the ecosystems of the Lake Teletskoe basin, its related obvious damage and the necessity to quantify the ongoing transformations. Aim. To assess the current state of a soil cover of the adjacent territory of Lake Teletskoe in terms of tourism and recreation impact. Methods. Comparative geographical and chemical as well as soil-ecological monitoring of studied indicators of early, short- and long-term diagnostics. Results and conclusions. Because of the tourist activities in the coastal zone of the mountain-forest belt of Lake Teletskoe, a developed path network transforming its natural ecosystems appeared. Some parameters of soil properties and composition on this path and in the sites not affected by recreation differed significantly. The analysis of water extract showed the decrease in acidity, the reduced content of ammonium and nitrate nitrogen, phosphates, a change in the concentration of calcium cations, potassium and magnesium in the top soil layer on the path, as compared to the undisturbed places. Soil trampling by recreants has damaged litter, decreased its thickness or completely destructed the promenade area. Reduction in litter reserves on the moderately developed paths exceeded by more than 2.7–4.0 times, whereas on the well-defined ones (as in the Altai State Biosphere Reserve with the established systemized movement across the territory), litter was absent at all on a few or even single paths. On weakly developed (fresh) paths, litter reserves turned out to be even higher than on the undisturbed areas or on the paths located next to a gravel site. Recreational loads were responsible for the 1.2–1.7 times increase in soil density of the upper (0–5 cm) layer, accompanied by a decrease in soil porosity and air supply. The hardness of soil was 1.3–1.5 times higher on the path than around it. The tourist effect on general physical properties of soil was traced to a depth of 20–30 cm, but maximum changes were noted in its upper (0–5 cm) layer. Recreational loads did not impact essentially on the aggregate soil composition. No significant changes, caused by tourist and recreational activities, were found in the elemental chemical composition of soils. The content of nutrients and lead were within the background and did not exceed the standardized values. The detected high concentrations of arsenic were not associated with the influence of tourist and recreational activities.

Properties of coal gangue aggregate concrete subjected to elevated temperatures

Using coal gangue as aggregate in concrete can lessen the environmental damage of solid waste. The chemical composition, mineral composition, microstructure and thermal stability of the gangue aggregate were examined firstly. Then the coarse aggregate of coal gangue (CCA) and fine aggregate of coal gangue (CFA) were used as to take the place of natural aggregates with a 50% substitution rate. After being exposed to 200 °C, 400 °C, 600 °C and 800 °C, the performances of concrete with coal gangue aggregate were investigated. The results indicated that as the temperature rose, the mass loss of concrete containing coal gangue gradually increased. The strength of concrete with CCA and CFA exposed to 200 °C was enhanced by 0.6% and 5.8%, respectively, in comparison with the unheated specimens. The splitting tensile strength and modulus of elasticity of specimens with CFA showed better than those of the specimens with CCA. After being exposed to 200 °C, 400 °C, 600 °C and 800 °C, the modulus of elasticity of the specimens containing CCA was reduced by 29.9%, 30.3%, 28.6%, and 13.0%, respectively, in comparison with the specimens with natural aggregate. They was reduced by 17.1%, 9.9%, 24.2%, and 13.0%, respectively, for the specimens containing gangue as fine aggregates.

Alpha-1 Antitrypsin Inclusions Sequester GRP78 in a Bile Acid-Inducible Manner.

The homozygous PiZ mutation (PIZZ genotype) constitutes the predominant cause of severe alpha-1 antitrypsin (AAT) deficiency and leads to liver disease via hepatocellular AAT aggregation. We systematically analysed the composition of AAT aggregates and studied the impact of bile acids. AAT inclusions were isolated from livers of PiZ overexpressing mice and PIZZ humans via fluorescence-activated and immunomagnetic sorting (FACS/MACS), while insoluble proteins were obtained via Triton-X extraction. Inclusion composition was evaluated through mass-spectrometry (MS), immunoblotting and immunostaining. Hepatocytes with versus without AAT aggregates were obtained via microdissection. Serum bile acids were assessed in 57 PIZZ subjects and 19 controls. Mice were administered 2% cholic acid (CA)-supplemented chow for 7 days. MS identified the key endoplasmic reticulum chaperone 78 kDa glucose-regulated protein (GRP78) in FACS/MACS pulldowns. GRP78 was also enriched in insoluble fractions from PiZ mice versus wild types and detected in insoluble fractions/MACS isolates from PIZZ liver explants. In cultured cells/primary hepatocytes, PiZ overexpression was associated with increased GRP78 mRNA/protein levels. In human livers, hepatocytes with AAT aggregates had higher GRP78 levels than hepatocytes without. PIZZ subjects displayed higher serum bile acid levels than controls and the highest levels were seen in individuals with liver injury/fibrosis. In PiZ mice, CA-mediated bile acid challenge resulted in increased liver injury and translocation of GRP78 into the aggregates. Our results demonstrate that GRP78 is sequestered within AAT inclusions. Bile acid accumulation, as seen in PIZZ subjects with liver disease, may promote GRP78 segregation and thereby augment liver damage. NCT02929940.

Effects of vegetation restoration on soil aggregate characteristics and soil erodibility at gully head in Loess hilly and gully region

Vegetation restoration can be effective in containing gully head advance. However, the effect of vegetation restoration type on soil aggregate stability and erosion resistance at the head of the gully is unclear. In this study, five types of vegetation restoration—Pinus tabulaeformis (PT), Prunus sibirica (PS), Caragana korshinskii (CKS), Hippophae rhamnoides (HR), and natural grassland (NG, the dominant species is Leymus chinensis)—in the gully head were studied. Soil aggregate composition and nutrient contents in the 0–20, 20–40, and 40–60 cm soil layers were also determined, and the soil stability parameters were used to evaluate the soil conditions. The soil erodibility (K) was then determined by measuring the granulometric composition and organic matter. The results showed that the particle size of soil aggregates under different vegetation restoration types was mainly < 0.25 mm, and the percentage of aggregate disruption (PAD) was 22.08–76.07%. This further indicated that in Loess hilly and gully regions, water-stable aggregates were more reflective of the stability of soil aggregates in a gully head under vegetation restoration. The > 0.25 mm aggregates (R> 0.25 mm), geometric mean diameter (GMD), and mean weight diameter (MWD) values of the three soil layers were the highest in PT and the lowest in NG, while the opposite was true for fractal dimension (D) and the percentage of aggregate disruption (PAD). The K ranged from 0.052 to 0.065 t·hm2·h·MJ− 1 mm− 1·hm− 2. GMD can be used to characterize the anti-erosion ability of soil, and increasing the soil organic carbon, total nitrogen, and clay content can effectively reduce soil erodibility. The comprehensive analysis indicated that the soil aggregates of arbors planted in the gully head had the highest stability and anti-erodibility, followed by shrubs and grasslands, and can be used to evaluate vegetation restoration measures in gully heads.

Long-Term Application of an Oil Residue Organic Fertilizer Improved Soil Physical Properties in the Root Zone of Jujube Trees

Organic fertilizers have been widely applied in Chinese agriculture. Soil aggregate composition and pore size distribution indicate the effects of fertilizer practices on soil quality. While the effects of the long-term application of organic fertilizers on total soil pore space have been reported, few studies have examined the distribution of connected pore spaces (of critical importance for solute transport in the soil). Soil physical and chemical properties influence plant growth and soil processes. We compared the effects of organic fertilizer application (10 years, 5 years, and no application) on soil connectivity pore structures and physicochemical properties within the root zone (20–40 cm depth) around date palms through CT scanning or core samples. Specifically, when the number of years of organic fertilizer application increased, the proportion of 2–0.25 mm particle size aggregates in the soil increased, and soil connectivity pore structure became more complex and stable, with higher connectivity, pore numbers, and numbers of pore throats. The connectivity of particles of the 0–300 μm size class of pores increased and the proportion of the 500–1000 μm class of pore throats increased. Soil organic matter and enzyme activity were significantly related to soil pore structure characteristics. In conclusion, the application of organic fertilizer improved soil pore structures, and the effects became more pronounced with the increased duration of application. These results provide theoretical and practical support for the application of organic fertilizer to improve soil structures in arid areas, and the findings have significant implications for sustainable agriculture in arid and semi-arid regions.

Asphalt-Aggregates Interface Interaction: Correlating Oxide Composition and Morphology with Adhesion

The adhesion between asphalt and aggregates is a complex physicochemical interfacial interaction that plays a critical role in determining the durability of asphalt pavement. This paper aims to investigate the determination mechanism of oxide composition and morphology of aggregates to their interfacial interaction and adhesion with asphalt, thereby optimizing the adhesion evaluation indicators of aggregates. Herein, the adhesion and interaction properties of aggregates were evaluated by photoelectric colorimetric, water boiling methods, and dynamic shear rheometer. The morphology and chemical compositions of 11 aggregates were characterized using X-ray diffraction, X-ray fluorescence, and scanning electron microscopy, thereby classified into 3 categories based on their oxide composition. The results indicate that the chemical composition of the aggregates is a crucial factor influencing adhesion rates, while micro-roughness impacts adhesion rates to varying degrees across different aggregate groups. Oxide composition was found to be a reliable predictor of adhesion properties, and incorporating surface roughness indicators improved the accuracy of adhesion rate prediction models. Both rheological indicators proved effective in characterizing the adhesion properties of aggregates, though they exhibited varying sensitivities depending on the aggregates categories.

Development and research of methods for strengthening the blades of a straw spreader

Abstract In this article, a comprehensive analysis of existing materials, hardening methods, design and features of the work of parts in the composition of aggregates is carried out. Based on this analysis, the choice of material for the base and reinforcing coating was carried out, and the most effective ways of strengthening the blades of the straw spreader were determined, which are installed on combines instead of similar imported parts. In the course of the study, the spread of blanks and hardened parts by weight, the degree of wear of knives in real operation, as well as the chemical and phase composition, structure and properties of reinforcing coatings were studied. 65G steel is proposed as a modern import-substituting material, and 6HV2C steel is proposed as a promising one. To increase the hardness and wear resistance of the knife blade, the technology of induction surfacing of modified hard alloys (composites) using high-frequency transistor converters (inverters) with a programmable mode is proposed. This technique makes it possible to achieve a more uniform heat distribution and ensure high accuracy of temperature control during the surfacing process, which improves the mechanical properties of the coating. The use of boron carbide and spherical tungsten carbide as a wear resistance modifier makes it possible to increase the hardness of the coating to 62-67 HRC, suppress the growth of dendritic structures, increase the adhesion of the functional filler to the composite matrix, reduce dispersion and increase the microhardness of the carbide phase, which together increases the potential wear resistance of the coating. The use of induction surfacing of modified hard alloys on knife blades contributes to a significant increase in their service life by increasing resistance to mechanical damage and wear.

Effects and mechanisms of different carbonaceous aggregates on coal tar pitch wettability behavior

The wettability of coal tar pitch is significantly influenced by the type of carbonaceous aggregate, directly impacting its effectiveness as a binder in industrial applications. This study systematically investigates the wetting behavior between various carbonaceous aggregates and coal tar pitch, providing critical insights into the physicochemical properties that influence the interaction. Specifically, we examine the potential of utilizing residual anodes as alternative aggregates. The rheological property of coal tar pitch was characterized to evaluate its suitability as a binder. Subsequently, the wettability of coal tar pitch on multiple carbonaceous aggregates was characterized by single particle wettability experiments, static wettability tests, and dynamic contact angle measurements. The results indicate that coal tar pitch exhibits the highest wettability with calcined coke, followed by residual anode, anthracite coal, and spent pot lining. Static wettability experiment revealed an inverse relationship between the specific surface area of the carbonaceous aggregates and their wettability. The Super-Depth-of-Field Microscope denoted that decreasing surface roughness improves the wettability of car tar pitch when the composition of aggregates is similar. X-ray diffraction and X-ray photoelectron spectroscopy tests showed that higher ideal graphite carbon content (Ig), decreased height of the crystallite (Lc), and increased surface functional groups (CN/CO/CS) all contribute to improve wettability. This study not only provides a comprehensive framework for selecting optimal carbonaceous aggregates but also delivers theoretical support for the reuse of residual anodes in industrial processes.

Arbuscular mycorrhizal fungi regulation of soil carbon fractions in coal mining restoration: Dominance of glomalin-related soil proteins revealed by stable carbon isotopes (δ13C)

Arbuscular mycorrhizal fungi (AMF) play a pivotal role in soil carbon cycling by orchestrating the recruitment of microbial communities and establishing hyphal networks. Understanding whether these attributes of AMF are instrumental in restoring soil carbon pools in areas disrupted by coal mining is crucial for forecasting soil organic carbon (SOC) dynamics in post-disturbance restoration sites. This study conducted a year-long, in-situ leaf decomposition experiment (comprising three shrubs: Amorpha fruticose, Caragana, and Sea buckthorn; two treatments: inoculated with AMF and without AMF inoculation) at the mycorrhizal restoration demonstration base in Inner Mongolia's mining area. Utilizing stable isotope technology, we investigated the mycorrhizal regulatory effects on aggregate carbon dynamics during the leaf decomposition process. Our findings showed that the presence of AMF hyphae accelerated carbon transformation within aggregates, resulting in augmented content of mineral-bound carbon (+6.1 %) and δ13C abundance (7.1 %) within microaggregates in sea buckthorn plots. Analysis employing random forest and partial least squares regression models corroborated that the regulation of mycorrhizal dynamics on aggregate carbon composition after fresh leaf input was indirectly influenced by GRSP rather than directly by AMF hyphae. In summary, our findings elucidate the evolving patterns of aggregate carbon dynamics following AMF inoculation in coal mining reclamation sites under field conditions. This underscored the efficacy of planting sea buckthorn and inoculating AMF during the vegetation restoration process of open-pit mine reclamation land in Inner Mongolia.

Effects of Enhanced Phytoremediation Techniques on Soil Aggregate Structure

In response to the current serious problem of soil cadmium (Cd) contamination in agricultural land, phytoremediation technology is a green and environmentally friendly application prospect; however, its remediation efficiency is currently limited. An enhanced phytoremediation technique was constructed using the biodegradable chelator aspartate diethoxysuccinic acid (AES) combined with the plant growth regulator gibberellic acid (GA3) to enhance the formation of maize. This technique has been proven to have a superior remediation effect. However, the safety of the restoration technique is of particular importance. The remediation process not only removes the contaminants, but also ensures that the original structure and stability of the soil is not damaged. In this regard, the constructed enhanced phytoremediation technique was further investigated in this study using soil columns. In combination with microscopic tests, such as X-ray diffraction and scanning electron microscopy, this study investigated the effects of the remediation process on the distribution characteristics of Cd in soil aggregates, and the structure and stability of soil aggregates. This was conducted by analyzing, as follows: plant growth conditions; the morphology, structure and mineral composition of soil aggregates in different soil layers; and the changes in these characteristics. The results demonstrated that the enhanced phytoremediation technique constructed in this study has a negligible impact on the morphology and mineral composition of soil aggregates, while exerting a limited influence on soil structure stability. This indicates that the technique can facilitate the safe utilization of remediated contaminated soil.

Proteomic analysis of wild boar meat: Effect of storage method and time on muscle protein stability

Oxidation processes affect proteins from various molecular pathways and are crucial for wild boar meat quality, shelf life and human health. This study investigated the effects of different storage methods on the formation and composition of oxygen-induced protein aggregates in the muscles of European wild boar (Sus scrofa scrofa). Vacuum packaging (VAC), modified atmosphere packaging (MAP) and dry-ageing (DA) were compared over a 21-day storage period. The results showed significant differences in protein aggregation depending on the method and storage time. The most intense protein aggregation occurred in the MAP (80 % O2), while air DA (20.9 % O2) resulted in intermediate levels of protein aggregation. Crucial myofibrillar proteins involved in aggregate formation were titin, myosin isoforms (MYH1, MYH2 and MYH7) and nebulin, which were cross-linked with small sarcoplasmic enzymes, such as muscle creatine kinase, isocitrate dehydrogenase and ATPase 1. High‑oxygen storage conditions also promoted the oxidation of ATP synthase, beta-enolase 3, ADP/ATP translocase and myoglobin.

Study on the Characteristics of Steel Slag and its Road Performance in Asphalt Mixture

Based on the characteristics of steel slag, the application progress of steel slag as aggregate in asphalt mixture is summarized. Firstly, the differences in mechanical properties, chemical composition and physical structure of steel slag aggregates treated by different methods are summarized. The surface structure of steel slag is rough and rich in edges and corners, showing good wear resistance and crushing resistance, but there are also problems such as high density, high water absorption and volume instability. Among them, volume instability is the key factor affecting the application of steel slag in asphalt mixture. Then, the effects of steel slag aggregate on the road performance of asphalt mixture, such as water stability, rutting resistance, high temperature stability and low temperature cracking resistance, are summarized in detail. It is found that steel slag instead of coarse aggregate in asphalt mixture can improve the performance of skid resistance, rutting resistance and fatigue resistance. The water damage performance is due to the different sources of steel slag, and the uncertainty of the change results is large. On the whole, steel slag instead of aggregate can improve the road performance to a certain extent, but the volume of steel slag aggregate is unstable, which may bring some variability. In the process of road application, targeted regulation should be carried out to ensure the stability of asphalt mixture performance.

Size distribution of aggregates across different aquatic systems around Japan shows that stronger aggregates are formed under turbulence

AbstractMarine aggregates, composed of various particles, play a crucial role in ocean carbon storage. The overall size distribution of the aggregates (number size spectra) is controlled by the balance between aggregation and disaggregation processes. Turbulence has been proposed to facilitate both aggregation and disaggregation by increasing the collision rate of aggregates or sometimes directly tearing them apart. Predominant processes driven by turbulence typically depend on the level of turbulence—relatively weak turbulence is associated with aggregation while stronger turbulence promotes disaggregation. Aggregate strength also plays a key role, as strongly bonded aggregates can withstand turbulence better, leading to lower disaggregation rates. While the relationship between turbulence and aggregate strength has been studied numerically and experimentally, field measurements remain limited. Here, we compare our number size spectra to turbulence intensity from the field measurements across different environmental settings around Japan to determine the effect of turbulence on aggregate strength. We combined measurements from 10 sites with different environmental settings and observed the flatter slopes (higher net aggregation rate) and shifts in the intersection lengths with an increase of turbulence, while strong turbulence is typically linked with disaggregation. Our findings suggested that stronger aggregates are formed under stronger turbulence and the overall population of strong aggregates also increases with an increase of turbulence intensity. We also compared our number size spectra with three other confounding factors (fluorescence, salinity, and aggregate compositions) to confirm the effects of turbulence are dominant in our aggregate dynamics.

Bank shocks and the debt structure

Abstract This article studies how sudden changes in bank credit supply impact economic activity. I identify shocks to bank credit supply based on firms’ aggregate debt composition. I use a model where firms fund production with bonds and loans. In the model, bank shocks are the only type of shock that imply opposite movements in the two types of debt as firms adjust their debt composition to new credit conditions. Bank shocks account for a third of output fluctuations and are predictive of the bond spread.

Varying Line-Broadening Sources by Tuning the Composition of DNA-Assembled Cyanine Tetramer Aggregates

Varying Line-Broadening Sources by Tuning the Composition of DNA-Assembled Cyanine Tetramer Aggregates

Effects of Long-Term Fenced Enclosure on Soil Physicochemical Properties and Infiltration Ability in Grasslands of Yunwu Mountain, China

Fenced enclosures, a proven strategy for restoring degraded grassland, have been widely implemented. However, recent climate trends of warming and drying, accompanied by increased extreme rainfall, have heightened soil erosion risks. It is crucial to assess the long-term effectiveness of fenced enclosures on grassland restoration and their impact on soil physicochemical properties and water infiltration capacity. This study investigated the effects of enclosure duration on soil organic matter, aggregate composition and stability, and infiltration capacity in Yunwu Mountain Grassland Nature Reserve, comparing grasslands with enclosure durations of 2, 14, 30, and 39 years. Results showed that grasslands enclosed for 14, 30, and 39 years had infiltration rates increased by 20.66%, 152.03%, and 61.19%, respectively, compared to those enclosed for only 2 years. After 30 years of enclosure, soil quality reached its optimum, with the highest root biomass, soil organic matter, aggregate stability, and a notably superior infiltration rate. The findings suggest that long-term fenced enclosures facilitate grassland vegetation restoration and enhance soil infiltration capacity, with the most significant improvement observed at the 30-year enclosure milestone, followed by a gradual decline in this effect.

Aggregate structure of agro-gray soils of Vladimir Opolye: composition and strength of aggregates

A complex of soils characteristic of the Vladimir Opole region was studied: agro-gray typical deep-arable soil, tongue-shaped agrozem and agro-gray gleyic soil. The high contrast of soil properties, which is due to the genesis of field landscapes, can be traced in the differences in the arable and subarable horizons of agro-gray soils at the aggregate and microaggregate levels. The soils have an excellent structural condition, high water resistance and mechanical strength of aggregates. In the aggregate structure of arable horizons, dependences on the position in the relief were found: down the slope the content of agronomically valuable aggregates decreases, the weighted average diameter of aggregates increases, the water resistance of aggregates and the mechanical strength of aggregates at capillary saturation decreases. However, the distribution and size of microaggregates, as well as the strength of aggregates in an air-dry state, reflects the complex genesis of the landscape and retains the influence of paleorelief with depressions and elevations. The weighted average diameter of microaggregates of arable horizons of the soils of the Vladimir Opole region is close to the chernozems of the Kursk region. The granulometric composition of the studied soils is typical of Vladimir Opolye soils and close to each other. In accordance with the classification of N.A. Kachinsky arable horizons are medium loamy, coarse silt, BT horizons are heavy loamy, coarse silt. The most structural is the arable horizon of agro-gray typical deep-arable soil, it has large microaggregates, it also has high water resistance and the highest content of agronomically valuable aggregates. The most homogeneous in terms of aggregate composition is tongue-shaped agrozem; the average diameter of aggregates and microaggregates in the arable and subarable horizons are equal and similar in the content of microaggregates and agronomically valuable aggregates. This soil is also highly water resistant. Agro-gray gleyic soil contains fewer agronomically valuable aggregates and its water stability is unsatisfactory.

The stoichiometric characteristics of carbon, nitrogen, and phosphorus in soil aggregates of Cryptomeria japonica plantation with stand ages in the Rainy Area of Western China.

Understanding the variations in soil aggregate composition, as well as the contents and stoichiometry of organic carbon (C), total nitrogen (N) and total phosphorus (P), in the surface layer of Cryptomeria japonica plantations with different stand ages can provide a theoretical basis for the optimized management of plantations and the improvement of soil fertility in the Rainy Area of West China. With the dry-sieving method, we measured the contents of soil aggregates with different sizes in the 0-15 and 15-30 cm soil layers across C. japonica plantations with five distinct developmental stages at Hongya Forestry Farm, Sichuan Province, including young stands (7 years old), middle-aged stands (13 years old), nearly mature stands (24 years old), mature stands (33 years old), and over-mature stands (53 years old). We further analyzed the C, N and P contents and ecological stoichiometric characteristics of soil aggregates. The results showed that the particle size composition of soil aggregates in C. japonica plantations varied among stand ages. The nearly mature and mature stands had higher proportion of large aggregates (0.5-1 and 1-2 mm), whereas the nearly mature stand had a lower proportion of micro-aggregates (0.053-0.25 mm) and the silt-plus-clay fraction (<0.053 mm). Moreover, the C, N and P contents and stoichiometric ratios in soil aggregate showed a unimodal pattern, which increased initially and then decreased with stand age, with peak values in the nearly mature and mature plantations. Furthermore, the C, N and P contents in aggregates in 0-15 cm soil layer were higher than that in the 15-30 cm soil layer. The highest C and N contents were found in the aggregates with particle sizes of 0.5-1 and 0.25-0.5 mm. In conclusion, the near-mature and mature stands of C. japonica plantations have higher nutrient content in soil aggregate, underscoring these stages was critical for maintaining soil fertility and advancing sustainable management practices.

SiO2 aerogel modified aggregates: Preparation, heat resistance and improvement mechanism

Modification of natural aggregates using SiO2 aerogel solution can not only radically reduce the rutting disease of asphalt pavement, but also avoid the problems of poor heat-resistant performance, mechanical strength and durability of ordinary heat-resistant aggregates. The effects of SiO2 aerogel solution type, modification method and SiO2 aerogel solution dosage on the thermal resistance and adhesion properties of SiO2 aerogel-modified aggregates (SM-Agg) were explored by orthogonal tests. Based on scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and infrared thermography, the surface micromorphology, elemental composition and dynamic thermal resistance properties of natural aggregate and SM-Agg were analyzed, respectively. The results showed that Both SiO2 aerogel solution type and dosage significantly affect the evaluation indexes and the modification of natural aggregates by soaking method using ZN-S type SiO2 aerogel solution with 15 % of the aggregate mass could obtain SM-Agg with good heat resistance and adhesion properties. The surface of SM-Agg was covered with a “gel layer” containing uniform and densely distributed SiO2 aerogel particles. The temperature of the top surface of the 18.3-mm-thick SM-Agg specimen gradually changed from 2.2°C higher than that of the natural aggregate to about 1.8°C lower than that of the natural aggregate within 60 min of heating at 55°C. The “gel layer” containing SiO2 aerogel particles forms one or more layers of three-dimensional heat-blocking mesh on the aggregate surface, which dramatically reduces the heat transfer area, prolongs the heat transfer path within the specimen, and increases the heat-reflecting capacity of the aggregate surface.

A multidimensional analysis reveals distinct immune phenotypes and the composition of immune aggregates in pediatric acute myeloid leukemia

Because of the low mutational burden and consequently, fewer potential neoantigens, children with acute myeloid leukemia (AML) are thought to have a T cell-depleted or ‘cold’ tumor microenvironment and may have a low likelihood of response to T cell-directed immunotherapies. Understanding the composition, phenotype, and spatial organization of T cells and other microenvironmental populations in the pediatric AML bone marrow (BM) is essential for informing future immunotherapeutic trials about targetable immune-evasion mechanisms specific to pediatric AML. Here, we conducted a multidimensional analysis of the tumor immune microenvironment in pediatric AML and non-leukemic controls. We demonstrated that nearly one-third of pediatric AML cases has an immune-infiltrated BM, which is characterized by a decreased ratio of M2- to M1-like macrophages. Furthermore, we detected the presence of large T cell networks, both with and without colocalizing B cells, in the BM and dissected the cellular composition of T- and B cell-rich aggregates using spatial transcriptomics. These analyses revealed that these aggregates are hotspots of CD8+ T cells, memory B cells, plasma cells and/or plasmablasts, and M1-like macrophages. Collectively, our study provides a multidimensional characterization of the BM immune microenvironment in pediatric AML and indicates starting points for further investigations into immunomodulatory mechanisms in this devastating disease.