Heterogeneous Sites Research Articles

MXene/AgNW composite material for selective and efficient removal of radioactive cesium and iodine from water

Toxic fission products, such as cesium (137Cs) and iodine (129I) are of great concern because of their long half-lives and high solubility in water. The simultaneous removal of Cs and I using a single adsorbent is an area of increasing interest. In this study, MXene/silver nanowire (AgNW) composite was synthesized through physical mixing and employed for simultaneous removal of iodide (I−) and cesium (Cs+) ions from contaminated water. The MXene/AgNW composite demonstrated excellent adsorption capacities of 84.70 and 26.22 mg/g for I− and Cs+, respectively. The experimental data supported the hypothesis of multilayer adsorption of Cs+ owing to the inter-lamellar structures and the presence of heterogeneous adsorption sites in MXene. The interaction between I− and the AgNW involved chemisorption followed by monolayer adsorption. MXene/AgNW composite material exhibited promising results in the presence of competitive ions under extreme pH conditions. Thus, synthesized composite materials holds promising potential as an adsorbent for the remediation of radioactive liquid waste.

Ten-year mortality after percutaneous coronary intervention, off-pump and on-pump surgery for complex coronary artery disease - who is the winner?

Abstract Aim The very long-term mortality of off-pump and on-pump CABG versus PCI in a randomized complex coronary artery disease (CAD) population is unknown. This study aims to investigate the impact of on-pump and off-pump coronary artery bypass grafting (CABG) versus percutaneous coronary intervention (PCI) on 10-year all-cause mortality. Methods and results The SYNTAXES trial randomized 1800 patients with three-vessel and/or left main CAD to PCI or CABG and assessed their survival at 10 years. In this sub-study, the hazard of mortality over 10 years was compared according to the technique of revascularization: on-pump CABG (n=725), off-pump CABG (n=128), and PCI (n=903). There was substantial inter-site variation in the use of off-pump CABG despite baseline characteristics being largely homogeneous amongst the three groups. The crude rate of mortality was significantly lower following on-pump CABG versus PCI (25.6% vs 28.4%, Hazard Ratio [HR] 0.79, 95% Confidence Interval [CI] 0.65-0.96), whilst it was comparable between off-pump CABG and PCI (28.5% vs 28.4%, HR 0.98, 95%CI 0.69-1.40). After adjusting for the nine variables included in the SYNTAX score II 2020, 10-year mortality remained significantly lower with on-pump CABG than PCI (HR 0.75 against PCI, p=0.009) (central figure). Conclusion In the SYNTAXES trial, 10-year mortality adjusted for major confounders was significantly lower following on-pump CABG compared to PCI, whilst off-pump CABG offered no prognostic survival benefit over PCI. Site heterogeneity in the technique used in bypass surgery has had measurable effects on treatment performance. Given its impact on outcomes, it should be pre-stratified in future studies.Central figure

Additive and non-additive genetic variance in juvenile Sitka spruce (Picea sitchensis Bong. Carr)

Many quantitative genetic models assume that all genetic variation is additive because of a lack of data with sufficient structure and quality to determine the relative contribution of additive and non-additive variation. Here the fractions of additive (fa) and non-additive (fd) genetic variation were estimated in Sitka spruce for height, bud burst and pilodyn penetration depth. Approximately 1500 offspring were produced in each of three sib families and clonally replicated across three geographically diverse sites. Genotypes from 1525 offspring from all three families were obtained by RADseq, followed by imputation using 1630 loci segregating in all families and mapped using the newly developed linkage map of Sitka spruce. The analyses employed a new approach for estimating fa and fd, which combined all available genotypic and phenotypic data with spatial modelling for each trait and site. The consensus estimate for fa increased with age for height from 0.58 at 2 years to 0.75 at 11 years, with only small overlap in 95% support intervals (I95). The estimated fa for bud burst was 0.83 (I95=[0.78, 0.90]) and 0.84 (I95=[0.77, 0.92]) for pilodyn depth. Overall, there was no evidence of family heterogeneity for height or bud burst, or site heterogeneity for pilodyn depth, and no evidence of inbreeding depression associated with genomic homozygosity, expected if dominance variance was the major component of non-additive variance. The results offer no support for the development of sublines for crossing within the species. The models give new opportunities to assess more accurately the scale of non-additive variation.

Abstract 14241: Alcohol Exposure Among Patients With Dilated Cardiomyopathy: A Report From the DCM Precision Medicine Study

Introduction: Alcohol-related cardiomyopathy is characterized by cardiac dysfunction and dilatation due to prolonged and excessive alcohol (ETOH) consumption. This study aims to determine the prevalence, use patterns and genetic associations of ETOH exposure in patient with dilated cardiomyopathy (DCM) and their first-degree relatives (FDR). Hypothesis: 1. There is increased prevalence of EOTH use among patients who develop DCM. 2. Non-genetic co-morbidities are more common in patients who use ETOH and developed DCM. 3. Probands and FDR who use ETOH and develop DCM are more likely to have genetic variants. Methods: We analyzed clinical and genetic data on individuals aged 18 and older enrolled in the US DCM Precision Medicine Study. Partial and full DCM phenotypic expression were included in the analysis. The AUDIT-C score was used to evaluate the intensity of ETOH use. ETOH use and presence of DCM-related rare genetic variants were examined in FDRs using GEE type logistic mixed models adjusted for intra-family correlation and site heterogeneity. Results: A total of 2,595 subjects (1,188 probands and 1,407 FDRs) were included. Prior and current ETOH users were 270 (23%) and 546 (46%) for probands, and 30 (10%) and 168 (54%) for FDRs with DCM/partial DCM. Avg. years of drinking were 25.2 for probands and 24.0 for FDRs with DCM/partial DCM; the percent with AUDIT-C positive scores were 31.5 for probands and 32.7 for FDRs with DCM/partial DCM. In probands, moderate or high/severe ETOH use was more likely to be in men, white, Hispanic and those with </=12 yrs. of education (p<0.001). Patients drinking heavily were more likely to have hypertension, diabetes, hypercholesterolemia, and history of arrhythmia/conduction disease. Among FDRs, DCM/partial DCM was associated with the presence of DCM-related variants but not with moderate-severe drinking years in quartile after controlling for demographics and comorbidities. ETOH use did not modify the genetic effect on DCM/partial DCM. Conclusions: There is a high prevalence of prior or current ETOH use among probands and FDRs with DCM/partial DCM with an average ETOH use between 24-25 yrs. ETOH use was not found to associate with DCM or to modify the association between the presence of genetic variants and development of DCM.

Privacy-preserving and lossless distributed estimation of high-dimensional generalized additive mixed models

Various privacy-preserving frameworks that respect the individual’s privacy in the analysis of data have been developed in recent years. However, available model classes such as simple statistics or generalized linear models lack the flexibility required for a good approximation of the underlying data-generating process in practice. In this paper, we propose an algorithm for a distributed, privacy-preserving, and lossless estimation of generalized additive mixed models (GAMM) using component-wise gradient boosting (CWB). Making use of CWB allows us to reframe the GAMM estimation as a distributed fitting of base learners using the L2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$L_2$$\\end{document}-loss. In order to account for the heterogeneity of different data location sites, we propose a distributed version of a row-wise tensor product that allows the computation of site-specific (smooth) effects. Our adaption of CWB preserves all the important properties of the original algorithm, such as an unbiased feature selection and the feasibility to fit models in high-dimensional feature spaces, and yields equivalent model estimates as CWB on pooled data. Next to a derivation of the equivalence of both algorithms, we also showcase the efficacy of our algorithm on a distributed heart disease data set and compare it with state-of-the-art methods.

Mechanisms of Zn removal from water by amorphous geopolymer: Molecular-level insights from X-ray absorption spectroscopy, isotope fractionation, and surface complexation modeling

Porous geopolymers have attracted widespread attention as promising heavy metal adsorbents that can be synthesized from aluminosilicate solid wastes. However, the precise microstructural evidence for adsorbed heavy metals on geopolymers remains unclear due to the insensitivity of conventional characterization techniques on minerals with amorphous structure and surface disorder. Batch adsorption and column experiments coupled with X-ray absorption spectroscopy (XAS), Zn stable isotope, and surface complexation model (SCM) were employed to reveal the Zn removal mechanisms with coal fly ash porous geopolymer (CFAPG) at a molecular scale. The macroscopic kinetic and isothermal adsorption of Zn on CFAPG were well described by the pseudo-second-order model and Bi_Langmuir equation, respectively, indicating the presence of abundant heterogeneous active sites on the CFAPG surface. Two types of active sites on the CFAPG surface were identified by XAS coupled with Zn isotopes in batch experiments at pH ≤ 6.0: one is pH-dependent and associated with tetrahedral zinc coordination, and the other is pH-insensitive and associated with octahedral zinc coordination; these sites were confirmed by the bidentate SCM as the variable charge site (surface complexation, >S-OH) and the permanent negative charge site (cation exchange, >X–), respectively. Furthermore, the important contribution of surface co-precipitation besides surface complexation and cation exchange to the Zn adsorption on CFAPG was identified by XAS coupled with SCM in a flow-through column experiment at pH >6.0. These investigations provide a systemic understanding of the Zn adsorption mechanisms on CFAPG and an SCM reference for the application and prediction of geopolymers in heavy metal-contaminated water remediations.

Spatial Heterogeneity and Strong Coupling of FeII /FeIII in anIndividual Metal-Organic Framework Nanoparticle for Efficient CO2 Photoreduction.

The synthesis and characterization of an FeII /FeIII metal-organic framework (MOF) nanocrystal with spatial heterogeneity that arises from the non-uniform distribution of different valence states is disclosed. The FeII /FeIII -Ni Prussian blue analog (PBA) delivers superior photocatalytic performance in the selective CO2 reduction reaction thanks to the strong FeII /FeIII coupling, with CO yield up to 12.27mmol g-1 h-1 and 90.6% selectivity under visible-light irradiation. Density functional theory calculation and experimental studies prove that the spatial heterogeneity of FeII /FeIII in the individual MOF nanocrystal not only directs and expedites the charge transfer within a catalyst particle but also creates the heterogeneity of catalytically-active Ni sites for efficient CO2 photoreduction. The current findings add to a growing literature of materials with compositional heterogeneity and provide a reference for future research.

Heterogeneity of Active Sites in the Polymer Chain Transfer Reactions at Olefin Polymerization over Multisite Supported Ziegler-Natta Catalysts.

In this review, we summarize and discuss our experimental data published in a number of papers on the transfer reactions of polymer chains in the polymerization of ethylene, propylene, and hexene-1, and the copolymerization of ethylene with α-olefins over multisite supported titanium-magnesium catalysts (TMC). Three groups of transfer reactions are discussed in the review: (1) transfer reactions with AlEt3 cocatalyst, (2) transfer reactions with hydrogen, and (3) transfer reactions with participation of α-olefins in the case of ethylene copolymerization with α-olefins. We have found polymerization conditions where it is possible to observe heterogeneity of active sites of TMC for all three groups of the indicated reactions. It is shown that (1) the transfer reaction with AlEt3 proceeds with higher reactivity on the active sites that produce polymers with low molecular weight; (2) the transfer reaction with hydrogen, in the case of α-olefin polymerization and copolymerization of ethylene with α-olefins, proceeds with higher reactivity on the active sites which produce polymers with high molecular weight; (3) the transfer reaction with α-olefins proceed with higher reactivity on the active sites that produce high molecular weight polymers.

Takes more than two to tango: Intrahousehold food system agency and its intricacies in South Africa

Intra-household food system agency is affected by individual physiology, environmental diversity, variations in social conditions, relational perspectives and distribution within families, resulting in differing capabilities and functionings which have a bearing on welfare. The study used the capability approach to assess intrahousehold food system agency, its determinants and welfare impact, taking a cross-sectional survey of 1184 households from three heterogenous study sites in South Africa. Poisson count regression, Propensity Score Matching and Monte Carlo Simulations were used in the study. Duration of stay within the community, tenure, employment status and household size were significant in the number of intrahousehold food system decisions made by female heads and none-nuclear family members, with however overall reduction in number of decisions made. Yet, when female heads showed agency in agricultural production and food expenditure, food security improved by 5 % and 6 %, respectively. On the other hand, it is reduced by between 4 % and 5 % for none-nuclear family members. Duration of stay in the community and age of household head had the highest contribution to agency variation. In conclusion, there are varied intrahousehold food system decisions made by various members of the households, resulting in varying degrees of food security. In addition, variations in the socio-economic factors of the households result in varied agency, especially for female household heads and other none-nuclear family members. Female-head intrahousehold food system agency should be promoted in lieu of their positive impact on food security, and their reduced decision-making capacity in hindsight.

On evaluating the hypothesis of shape similarity between soil particle-size distribution and water retention function

Two pedotransfer functions (PTFs) are available in the literature enabling the soil water retention function (WRF) to be estimated from knowledge of the soil particle-size distribution (PSD), oven-dry soil bulk density (b), and saturated soil water content (s): i) the Arya and Heitman model (PTF-AH) and ii) the Mohammadi and Vanclooster model (PTF-MV). These physico-empirical PTFs rely on the hypothesis of shape similarity between PSD and WRF, and do not require the calibration of the input parameters. In the first stage, twenty-seven PSD models were evaluated using 4,128 soil samples collected in Campania (southern Italy). These models were ranked according to the root mean square residuals (RMSR), corrected Akaike Information Criterion (AICc), and adjusted coefficient of determination (R2adj). In the second stage, three subsets of PSD and WRF data (DS-1, DS-2, and DS-3), comprising 282 soil samples, were used to evaluate the two PTFs using the best three PSD models selected in the first stage. The hypothesis of shape similarity was assumed as acceptable only when the RMSR value was lower than the field standard deviation of the WRFs (*), which is viewed as a tolerance threshold and computed from the physically-based scaling approach proposed by Kosugi and Hopmans (1998). In the first study area (DS-1), characterized by a fairly uniform, loamy textured volcanic soil, the PTF-AH outperformed the PTF-MV and both PTFs provided reasonable performance within the acceptance threshold (i.e., RMSR < *). In the other two heterogeneous field sites (DS-2 and DS-3, characterized by soil textural classes that span from clay and clay-loam to loam and even sandy-loam soils), the PTF-MV (with 3% to 6% RMSR surpassing *) outperformed the PTF-AH (with 8% to 30% RMSR surpassing *) and the majority of RMSR values were larger than those obtained in the original studies. The mean relative error (MRE) revealed that the PTF-MV systematically underestimates the measured WRFs, whereas the PTF-AH provided negative MRE values indicating an overall overestimation. The outcomes of our study provide a critical evaluation when using calibration-free PTFs to predict WRFs over large areas.

Environmental effects on ammonium adsorption onto clay minerals: Experimental constraints and applications

Adsorption of ammonium (NH4+) by clay minerals in soil/sediment and altered oceanic crust plays an important role in Earth's geological nitrogen cycle by transporting nitrogen from the biosphere and hydrosphere into the lithosphere. Clay minerals have also been proposed to play an important role in catalyzing abiotic synthesis of organic compounds (which also requires adsorption enrichment of NH4+) for the origin of life. Consequently, nitrogen in clay minerals could be used as a potential tracer for reconstructing paleo-environments and searching for life on extraterrestrial planets and moons. However, the premise of these applications, i.e., how different environmental conditions (e.g., ambient pH, temperature, salinity and aqueous NH4+ concentration) would affect NH4+ adsorption onto clay minerals, is still poorly understood. In this study, we carried out laboratory experiments to examine the NH4+ adsorption behavior of several clay minerals (montmorillonite, vermiculite, illite, chlorite, kaolinite) under conditions varying in aqueous NH4+ concentration (20, 50, 100, 200, 500, 1000 mg/L), pH (2, 5, 7), salinity (fresh water vs. artificial seawater), and temperature (23, 50, 70 °C). Our results show that the NH4+ adsorption on all studied minerals is very fast (reaching equilibrium within a few minutes). The NH4+ adsorption capacity is however strongly mineral-dependent and follows the order of vermiculite ≈ montmorillonite ≫ illite > kaolinite ≈ chlorite. The much higher NH4+ adsorption capacities of vermiculite and montmorillonite can be attributed to the NH4+ adsorption in their interlayer sites in addition to the surface and edge sites that dominate the NH4+ adsorption in illite, kaolinite, and chlorite. But illite contains some frayed edge sites that are accessible to NH4+ adsorption, and thus has higher adsorption capacity than kaolinite and chlorite. The NH4+ adsorption on all these clay minerals is highly susceptible to environmental conditions (e.g., aqueous NH4+ concentration, pH, temperature, and salinity). For example, the NH4+ adsorption capacities of montmorillonite and vermiculite significantly decrease following the increase in salinity and the decreases in pH and aqueous NH4+ concentration. Our experimental data can be best fitted by the Freundlich Model, which suggests that NH4+ adsorption on clay minerals likely occurs in energetically heterogeneous surface sites. Based on these results, we provide new insights into the understanding of NH4+ migration from seawater to sediments and altered oceanic crust, preservation capability of the paleoenvironmental nitrogen signature in clay minerals, and optimal conditions for clay to catalyze organic synthesis toward the origin of life on the early Earth.

Adsorption of hexavalent chromium using Water Hyacinth Leaf Protein Concentrate/Graphene Oxide hydrogel.

Water Hyacinth Leaf Protein Concentrate/Graphene Oxide (WHLPC/GO) hydrogel was synthesized for the removal of Cr(VI) from wastewater. About 90% of the prepared hydrogel constitutes WHLPC. The prepared material was characterized by FT-IR and XRD. The process variables such as pH, contact time, adsorbentdosage, initial Cr(VI) concentration, and temperature were optimized using a batch mode experiment. Kinetic studies were alsoconducted and it was observed that the chemosorptive pseudo-second-order best described the adsorption system with a correlation coefficient(R2) of 0.984. The highest adsorption capacity of 322.00 mg/g was achieved at pH 1.0, and equilibrium was achieved within 420 min. Various isotherm models were analyzed using non-linear fitting. It was found that the Sips model provides the best fit, indicating heterogeneous and uniform active site surface adsorption of Cr(VI) on the WHLPC/GO. The reuse efficiency of the synthesized material was also found to be greater than 84% for five consecutive cycles. Thermodynamic studies were conducted and results revealed that the adsorption was spontaneous and endothermic.

Sand dam contributions to year-round water security monitored through telemetered handpump data

Sand dams are a form of rainwater harvesting, prolific in arid and semi-arid lands. Water is provided partly via handpumps, which, as the only improved method of abstraction from sand dams, are important for drinking water security. Accelerometers and cellular transmitters were fitted to 30 handpumps by the Africa Sand Dam Foundation (ASDF) in 2019 to monitor the use and reliability of the handpumps by recording hourly water volume abstracted. Data from April 2019 to October 2021 for 26 of these sites, alongside qualitative data, were analysed and each handpump’s contribution to year-round water security was explored, focusing on the long dry season when water supply from other sources is compromised. ion was over 20 times higher in the long dry season than in any other season, and at sites with higher salinity, higher livestock use, and larger dam wall area. At 21 wells, abstraction was still being recorded at the end of at least one long dry season; however, high spatial and temporal heterogeneity between pumps and seasons means that not all sand dams deliver reliable water supply year-round. Quantifying the contribution that sand dams make to water security is crucial for understanding their resilience against a changing climate and can aid decision makers when choosing the most appropriate water management technique. Knowledge of temporal and site heterogeneity in abstraction can inform when other water sources need increasing and can help with sand dam design optimisation. Overall, our results indicate the positive contribution that sand dams make to year-round water security through the water that is abstracted through handpumps.

Is Over-parameterization a Problem for Profile Mixture Models?

Biochemical constraints on the admissible amino acids at specific sites in proteins lead to heterogeneity of the amino acid substitution process over sites in alignments. It is well known that phylogenetic models of protein sequence evolution that do not account for site heterogeneity are prone to long-branch attraction (LBA) artifacts. Profile mixture models were developed to model heterogeneity of preferred amino acids at sites via a finite distribution of site classes each with a distinct set of equilibrium amino acid frequencies. However, it is unknown whether the large number of parameters in such models associated with the many amino acid frequency vectors can adversely affect tree topology estimates because of over-parameterization. Here, we demonstrate theoretically that for long sequences, over-parameterization does not create problems for estimation with profile mixture models. Under mild conditions, tree, amino acid frequencies, and other model parameters converge to true values as sequence length increases, even when there are large numbers of components in the frequency profile distributions. Because large sample theory does not necessarily imply good behavior for shorter alignments we explore the performance of these models with short alignments simulated with tree topologies that are prone to LBA artifacts. We find that over-parameterization is not a problem for complex profile mixture models even when there are many amino acid frequency vectors. In fact, simple models with few site classes behave poorly. Interestingly, we also found that misspecification of the amino acid frequency vectors does not lead to increased LBA artifacts as long as the estimated cumulative distribution function of the amino acid frequencies at sites adequately approximates the true one. In contrast, misspecification of the amino acid exchangeability rates can severely negatively affect parameter estimation. Finally, we explore the effects of including in the profile mixture model an additional "F-class" representing the overall frequencies of amino acids in the data set. Surprisingly, the F-class does not help parameter estimation significantly and can decrease the probability of correct tree estimation, depending on the scenario, even though it tends to improve likelihood scores.

Design of multifunctional 1D/2D polypyrrole nanotubes@pg-C3N4 binary nanocomposite for removal of mercury (Hg2+) from wastewater and supercapacitor applications

A multifunctional, highly efficient, 1D/2D Polypyrrole nanotubes@pg-C3N4 binary nanocomposite was prepared using a one-pot ultra-sonication approach. The influence of 1D and 2D nanomaterials on the behavior of developed PPy-NTs-based nanocomposite for eliminating Hg2+ ions was explored. The developed nanocomposite revealed greater adsorption performance to eliminate Hg2+ions from contaminated water. The PPy-NTs/pg-C3N4 potential as an excellent sorbent for the removal of Hg2+ and possible mechanisms were assessed using batch experiments involving multiple factors that can also optimize the maximum adsorption conditions that were found to be at pH = 5, 1 h stirring time, and 0.5 g/L adsorbent dosage. The maximum Hg2+ absorption capacity reached was 197 mg/g. The data were well fitted with the pseudo-second-order kinetic model, which indicates that the chemisorption process controls the Hg2+ ions adsorption onto the pg-C3N4/PPy-NTs. The four adsorption isotherms models were applied to analyze the adsorption of Hg2+ ions on the developed adsorbent. The data were well described with Freundlich isotherm, revealing the presence of heterogeneous adsorption sites. The effect of temperature and thermodynamic considerations were investigated, showing that Hg2+ ion adsorption is endothermic. Additionally, the prepared material was explored for the supercapacitor application. It delivered an outstanding electrochemical supercapacitor performance and remarkable cycling stability.

Spatiotemporal assessment and scenario simulation of the risk potential of industrial sites at the regional scale

Spatiotemporal risk and future evolutionary distribution characteristics of industrial sites are crucial for regional environmental supervision. However, traditional site survey methods have long cycles, high costs, and small coverage and usually only consider the static risk of a single industrial site to a single receptor. Low-cost, large-scale, and long-term multi-source data can compensate for the shortcomings of traditional site surveys. Previous studies have rarely considered the spatiotemporal heterogeneity of industrial sites and assessed their dynamic risks at the regional scale. This study used China's Yangtze River Delta Urban Agglomeration as the study area. We assessed the risk potential of industrial sites from 2000 to 2020 using multi-source and multiperiod data. We also simulated the risk potential for 2030 and 2050 using a patch-generating land use simulation (PLUS) model under different scenarios. The results indicated that the proportion of medium- and high-risk potential grids from 2000 to 2020 ranged from 2.53 % to 5.61 % in the study area, with the vast majority of areas (94.39 %–97.47 %) having low- or no-risk potential. The PLUS model exhibited remarkable reliability from 2005 to 2020, with the overall accuracy, Kappa coefficient, and Moran's index ranging from 83 % to 89 %, 0.38 to 0.59, and 0.34 to 0.56, respectively. The future prediction results indicated that the number of high-risk potential grids (>5 %) showed an upward trend under natural development scenarios in 2030 and 2050 and a downward trend under the ten-chapter soil pollution action plan or strict control scenarios. This study provides vital information for addressing the challenges of industrial site management and environmental risks in similar regions.

A developed dual-site Langmuir model to represent the high-pressure methane adsorption and thermodynamic parameters in shale

Comprehending the mechanism of methane adsorption in shales is a crucial step towards optimizing the development of deep-buried shale gas. This is because the methane adsorbed in shale represents a significant proportion of the subsurface shale gas resource. To properly characterize the methane adsorption on shale, which exhibits diverse mineral compositions and multi-scale pore sizes, it is crucial to capture the energy heterogeneity of the adsorption sites. In this paper, a dual-site Langmuir model is proposed, which accounts for the temperature and pressure dependence of the density of the adsorbed phase. The model is applied to the isothermals of methane adsorption on shale, at pressures of up to 30 MPa and temperatures ranging from 40 to 100 °C. The results show that the proposed model can describe the adsorption behavior of methane on shale more accurately than conventional models, which assume a constant value for the density of adsorbed phase. Furthermore, the proposed model can be extrapolated to higher temperatures and pressures. Thermodynamic parameters were analyzed using correctly derived equations. The results indicate that the widely used, but incorrect, equation would underestimate the isosteric heat of adsorption. Neglecting the real gas behavior, volume of the adsorbed phase, and energy heterogeneity of the adsorption sites can lead to overestimation of the isosteric heat of adsorption. Furthermore, the isosteric heat evaluated from excess adsorption data can only be used to make a rough estimate of the real isosteric heat at very low pressure.

The Predictive Value of Circulating Exosomal PD-L1 in Cervical Cancer Immunotherapy

Programmed death ligand 1 (PD-L1) expression was wildly used as a predictor of immune Check-Point Inhibitors (ICIs) efficiency. However, emerging results showed that PD-L1 was of great heterogeneity in sampling time and site. Recently, some studies found that exosomal PD-L1(ExoPD-L1) was related to ICIs response. In this study, we aimed to explore the predictive value of ExoPD-L1 in ICIs treatment of cervical cancer (CC) for the first time. A total of 40 primarily diagnosed CC patients who accepted radical radiotherapy (RT) from March 2021 to October 2022 were included. The consecutive tumor sample were collected before and during RT. Another 37 advanced CC patients who accepted ICIs combination therapy from June 2020 to October 2022 were enrolled in this study. Blood samples were collected from each participant before and during treatment. Exosomes were derived by differential centrifugation, which was further identified by Western blot (WB) (CD9/TSG101/Calnexin), transmission electron microscope analysis and nanoparticle tracking analysis. ExoPD-L1 detection was conducted by enzyme-linked immuno-sorbent assay (ELISA). The knockout of PD-L1 was conducted via CRISPR/Cas9 assay and the overexpress of PD-L1 was conducted by lentiviral transfection. CD8+ T cells were extracted from murine spleen by CD8+ T Cell Isolation Kit. Immune cells and cytokines markers were detected by multicolor flow cytometry. The consecutive detection of PD-L1 showed a dynamic change during RT. Compared with the level before RT, PD-L1 expression elevated in most patients (87.5%, 35/40) after RT. And the responders (n = 18) had elevated ExoPD-L1 level at the first two circles in the ICIs combination therapy (P<0.001). Whereas the level of pre-treatment ExoPD-L1 couldn't stratified clinical responders and non-responders (P = 0.181). The median follow-up time was 14.13 months. The mPFS in increased group vs. decreased group: not reach vs.11.02 months (P = 0.025, HR: 0.218, 0.052-0.913). Continuous blood sampling of mice models also found that effective therapeutic intervention could increase ExoPD-L1 in the early stage. The combination of exosome inhibitor GW4869 and anti-PD-1 further inhibited tumor growth. Mice were injected with external ExoPD-L1OE and ExoPD-L1KO. The results showed that ExoPD-L1OE suppressed body immunity and promoted tumor growth. The results of flow cytometry showed that ExoPD-L1OE inhibited CD8+ T cells from releasing interferon-and granzyme B. And ExoPD-L1OE also suppressed the CD8+ T cells proliferation in murine spleen. The coculture of CD8+ T cells and exosomes in vitro also confirmed the above conclusion. Compared with unstable and impressionable tumoral PD-L1, ExoPD-L1 seems to be better predictor for the efficacy of immunotherapy in CC, which was with easy accessibility and continuation. Exosome PD-L1 played an immunosuppressive role by inhibiting the proliferation and functional factor release of CD8+ T cell.

Modeling of heterogeneous site energy distributions in precipitate nucleation

The simulation of heat changes resulting from phase transitions can help to interpret differential scanning calorimetry (DSC) measurements, e.g. of metallic alloy systems in which multiple reactions overlap during non-isothermal heat treatments. So far, simulated DSC curves mostly exhibit sharp reaction peaks as commonly just one mean energy value for a certain type of nucleation site is assumed. This work proposes an efficient model for treating heterogeneous nucleation site energy variations within the framework of classical nucleation theory (CNT). The site energies are assumed to vary according to a Rayleigh distribution and a scaling function. The effect on the nucleation behavior of precipitates is studied. A consideration of the distribution of heterogeneous site energies has the potential to significantly smoothen the numerical treatment of precipitation processes compared to the non-distributed case. The comparison to previously published simulations of DSC curves during the cooling of an AA6005 aluminum alloy demonstrates the advantages of this extension, especially for slow cooling rates.

Synthesis of a porous hollow magnetic molecularly imprinted microsphere by O/W/O composite emulsion polymerization for specifically recognizing bovine serum albumin

Molecular imprinting technology is highly successful for low-molecular-weight molecules, but is still confronted with many challenges for proteins. This study introduces a strategy to synthesize hollow magnetic molecularly imprinted microspheres (HMMIMs) under Fe3O4 magnetic nanoparticles matrix, by oil-in-water-in-oil composite emulsion polymerization with alkylphenol ethoxylates and Span-80 as emulsifiers. The synthesis conditions after optimization were 1.0 mmol thermo-sensitive functional monomer N-isopropylacrylamide, 1.0 mmol cross-linker N, N-methylene bisacrylamide, 2.0 wt% vinyl-modified silk fibroin, and 50 mg Fe3O4@COOH nanoparticles. The morphology structure and the forming process of the acquired HMMIMs were well characterized by POM, SEM, TEM and FT-IR. The HMMIMs were synthesized successfully with a porous structure and large specific surface area. The particle size of the obtained HMMIMs was at 10–20 µm. The obtained microspheres were superparamagnetic and thermo-responsive. The HMMIM adsorption capacity at 25 °C toward bovine serum albumin (BSA) was 89.9 mg/g and the BSA separation factor in BSA/BHb mixtures was 2.12. A good separation efficacy toward BSA was also observed in bovine whole blood. The prepared HMMIM possessed heterogeneous active sites, the BSA adsorption process on HMMIM was chemisorption controlled.