Dominant Site Research Articles

Ion Irradiation-Induced Coordinatively Unsaturated Zn Sites for Enhanced CO Hydrogenation.

Defect engineering critically influences metal oxide catalysis, yet controlling coordinatively unsaturated metal sites remains challenging due to their inherent instability under reaction conditions. Here, we demonstrate that high-flux argon ion (Ar+) irradiation above recrystallization temperatures generated well-defined coordinatively unsaturated Zn (CUZ) sites on ZnO(101̅0) surfaces that exhibited enhanced stability and activity for CO hydrogenation. Combining low-temperature scanning probe microscopy, ambient pressure X-ray photoelectron spectroscopy, and surface-ligand infrared spectroscopy with density functional theory calculations, we identified <12̅10> step edges exposing CUZ sites as the dominant active sites. These sites facilitate hydrogen-assisted CO dissociation through a mechanism distinct from formate-mediated pathways on stoichiometric ZnO. The ion-irradiation approach effectively addressed instability of Zn species, a major problem in ZnO catalysis, enabling stable performance in syngas conversion when combined with zeolites. Our atomic scale investigation provided spectroscopic fingerprints for active sites on the ZnO catalyst and insights into the structure-activity relationships of ZnO for CO hydrogenation. Our approach for engineering thermally stable defect sites in oxide catalysts provided opportunities for rational catalyst design beyond traditional preparation methods.

State and culture in sustainability transformations: structural power, democracy, and the promise of a Marcusian cultural politics of critical meaning-making

The concept of sustainability transformation highlights the need not merely for new environmental policies but for transformational change of societal systems in response to the ecological crisis, including a profound shift in values, ideas, and cultural meanings. Yet, according to historical-institutionalist state theory, the imperatives of the liberal-capitalist democratic welfare state give rise to a “glass ceiling” of transformation that limits prospects for such systemic change beyond quality-of-life improvements that remain consistent with liberal capitalism. Exploring the potential of cultural meaning-making to break this glass ceiling, I draw on various strands of critical theory to identify the operation of ideological power at the level of both the state and the cultural realm as what creates the glass ceiling of transformation. This makes the cultural realm at once a possible emancipatory force and a site of domination of its own. I suggest that the critical thought of Herbert Marcuse offers an account of a critical-democratic culture that promises to arise precisely out of this ambiguity and that must be understood as a crucial foundation for sustainability transformation.

Single-Atom Metal Species as A Promoter to Enhance Heterogeneous Catalysis.

Single-atom catalysts (SACs) have emerged as a focal point of research in the field of heterogeneous catalysis. This paper reviews the progress in the studies of single atoms as promoters in various catalytic reactions, elucidating their distinctive role in comparison to the dominant active sites. We provide a discussion on the application of single-atom promoters (SAP) within host-guest systems in various catalysts, including metal oxide supported catalysts, molybdenum carbide-based catalysts, bimetallic catalysts, and others. The behavior of SAP is diverse. They often promote the formation of oxygen vacancies for oxide support, leading to local site reconstruction that creates specific reaction route. Moreover, they can also precisely modify the electronic structure of hetero-metal atomic or nanoparticle sites, then regulating the adsorption of reactants or intermediates and catalytic performance. Finally, the potential for the development of SAP is outlined, proposing novel approach for the design of SACs with enhanced activity and stability.

The antinomies of feed and feeding in animal agriculture

This paper is about the environmental politics and ethics of animal agriculture through a focus on feed and feeding. We review a large and interdisciplinary body of scholarship on animal agriculture to show that the production of feed, and the feeding of animals in confined systems of production, is associated with degradation, exploitation, and violence. At the same time, and especially in the current conjuncture, feed and feeding research and scholarship highlight ways to address and mitigate animal agriculture's environmental problems while also providing hope for more ethical multispecies relations on the farm. We map the antinomies of feed and feeding through three analytical registers: feed as object, feeding as practice, and feed/ing as conversion. We argue that feed and feeding are at the center of the contemporary politics and ethics of animal agriculture — both as a site of exploitation and domination, but also as a contested promise of a more ethical and sustainable animal agriculture. Our conclusion examines how the antinomies of feed and feeding are both incompatible and yet bound together, an issue that we argue provides critical insights into the contemporary environmental politics and ethics of animal agriculture.

Kinetic insights into structure sensitivity of Ru catalyzed l-alanine hydrogenation to alaninol

Ru(101) sites are identified as the dominant active sites for the hydrogenation of l-alanine to alaninol.

Partially Interstitial Silicon‐Implanted Ruthenium as an Efficient Electrocatalyst for Alkaline Hydrogen Evolution

To enhance the alkaline hydrogen evolution reaction (HER), it is crucial, yet challenging, to fundamentally understand and rationally modulate potential catalytic sites. In this study, we confirm that despite calculating a low water dissociation energy barrier and an appropriate H adsorption free energy (ΔG*H) at Ru‐top sites, metallic Ru exhibits a relatively inferior activity for the alkaline HER. This is primarily because the Ru‐top sites, which are potential H adsorption sites, are recessive catalytic sites, compared with the adjacent Ru‐hollow sites that have a strong ΔG*H. To promote the transformation of Ru‐top sites from recessive to dominant catalytic sites, interstitial Si atoms are implanted into the hollow sites. However, complete interstitial implantation leads to a high water dissociation energy barrier at the RuSi intermetallic surface. Thus, we present a partial interstitial incorporation strategy to form a Ru–RuSi heterostructure that not only converts the Ru‐top sites from recessive to dominant catalytic sites but also preserves the low water dissociation energy barrier at the Ru surface. Moreover, the spontaneously formed built‐in electric fields bidirectionally optimize the adsorption ability of the Ru sites, thereby greatly reducing the thermodynamic energy barrier and enhancing the alkaline HER.

Partially Interstitial Silicon-Implanted Ruthenium as an Efficient Electrocatalyst for Alkaline Hydrogen Evolution.

To enhance the alkaline hydrogen evolution reaction (HER), it is crucial, yet challenging, to fundamentally understand and rationally modulate potential catalytic sites. In this study, we confirm that despite calculating a low water dissociation energy barrier and an appropriate H adsorption free energy (ΔG*H) at Ru-top sites, metallic Ru exhibits a relatively inferior activity for the alkaline HER. This is primarily because the Ru-top sites, which are potential H adsorption sites, are recessive catalytic sites, compared with the adjacent Ru-hollow sites that have a strong ΔG*H. To promote the transformation of Ru-top sites from recessive to dominant catalytic sites, interstitial Si atoms are implanted into the hollow sites. However, complete interstitial implantation leads to a high water dissociation energy barrier at the RuSi intermetallic surface. Thus, we present a partial interstitial incorporation strategy to form a Ru-RuSi heterostructure that not only converts the Ru-top sites from recessive to dominant catalytic sites but also preserves the low water dissociation energy barrier at the Ru surface. Moreover, the spontaneously formed built-in electric fields bidirectionally optimize the adsorption ability of the Ru sites, thereby greatly reducing the thermodynamic energy barrier and enhancing the alkaline HER.

Histopathological and Immunohistochemical Evaluation of African Swine Fever Pigs in Bali Province

African Swine Fever (ASF) is a disease affecting pigs, caused by a double-stranded DNA virus that is not transmissible to humans or other animals. It leads to significant economic losses due to high morbidity and mortality rates, particularly in densely populated pig regions like Bali Province. During the ASF outbreak from June to December 2023, this study conducted histopathological research on clinical samples. Biological materials from twelve pigs confirmed positive for ASF via qPCR examination were histopathologically analyzed. Tissue samples from various organs underwent processing and examination using hematoxylin and eosin staining. Immunohistochemistry (IHC) was employed to detect the ASF virus’s p54 protein. Clinical symptoms, anatomical pathology, and histological examination revealed characteristic acute ASF lesions. Immunohistochemistry consistently showed p54 viral antigen distribution in mononuclear cells/macrophages across various organs, with the spleen and lymph nodes being dominant sites in 12 pigs (100%). This comprehensive study demonstrates the effectiveness of IHC in detecting the ASF virus and characterizing its histopathology.Keywords: ASF; histopathology; immunohistochemistry

Energy, Exergy and Exergo-economic analyses of supercritical CO2 cycles for the exploitation of a geothermal resource in the Italian water dominant Amiata site

Alternative powerplant layouts to commonly applied flash technology is investigated for the water dominant geothermal location of Amiata Mountain, Italy. The proposed solution avoids flashing the brine stream by a borehole pump capable of maintaining pressurized conditions, thus reducing the amount of non-condensable gases released when reaching the ground level. Therefore, the need of a gas treatment section is completely avoided. The heat recovered from the hot brine at ground level is transferred to different supercritical CO2 cycle configurations, equipped with high efficiency Printed Circuit Heat Exchangers (PCHE). The optimal 45.5% calculated exergy efficiency was achieved for the recuperative cycle with intercooling and reheat, which however didn’t show the optimal electricity costs (8.092 c€/kWh) because of the more complex heat exchangers network. The lowest cost of electricity (7.4 c€/kWh) was found for the recuperative cycle configuration. These costs are in line with the current levels of geothermal binary cycles, but almost doubled compared to the current single flash +ORC solution, due to a 40-50% reduction of power output with sCO2 cycles. On the other hand, sCO2 binary cycles could guarantee an almost zero environmental impact, which is the main reason for social concerns related to the current flash powerplants.

Expression of influenza A H1N1 and H3N2 viruses Mosaic-HA1 antigens and evaluation of its immunogenicity in mice

Vaccination is the most effective measure for reducing and preventing influenza and related complications. In this study, we analyzed the mutation trend and the antigen dominant site changes of the amino acid sequence of hemagglutinin subunit 1 (HA1) of human influenza A virus (IAV) in the northern hemisphere from 2012 to 2022. According to the HA1 sequences of A/Darwin/6/2021 (H3N2) and A/Wisconsin/588/2019 (H1N1) recommended by the World Health Organization in the 2022 influenza season in northern hemisphere, we employed the mosaic algorithm to design three Mosaic-HA1 antigens through stepwise substitution. Mosaic-HA1 was expressed and purified in 293F cells and then mixed with the alum adjuvant at a volume ratio of 1:1. The mixture was used to immunize BALB/c mice, and the immunogenicity was evaluated. Enzyme-linked immunosorbent assay showed that Mosaic-HA1 induced the production of IgG targeting two types of HA1, the specific IgG titers for binding to H3 protein and H1 protein reached 105 and 103 respectively. The challenge test showed that Mosaic-HA1 protected mice from H3N2 or H1N1. This study designs the vaccines by recombination of major antigenic sites in different subtypes of IAV, giving new insights into the development of multivalent subunit vaccines against influenza.

Constructing Angstrom‐Level Ion Pocket Array in 1D Channel Wall for Efficient Lithium Ion Sieving

AbstractThe rapid development of new energy industry is leading to the scarcity of lithium (Li) metal. Rational design of adsorbents for efficient separation of Li+ ion from aqueous media is pivotal to solve the recovery of this valuable resource. Current adsorbents generally suffer from the drawbacks in adsorption capacity, kinetics, and selectivity. Herein, a novel and ultra‐stable metal–organic framework is designed for Li+ separation. The dense oxygen atoms on the cambered wall of its 1D channel encircle to form angstrom‐level tetrahedral ion pockets array, acting as the dominant adsorption sites. This rational distribution of the array avoids the pore blockage caused by the pre‐adsorbed ions, thereby accelerating the diffusion of subsequent ions into the interior pore. Meanwhile, this tetrahedral pocket shows distinct electronegativity and strong chelation effect for Li+. Benefiting from these specifics, this adsorbent exhibits a record‐breaking adsorption capacity for Li+ (76.1 mg g−1) and short equilibrium time (30 min). Moreover, the selective adsorption of Li+ over Na+, K+, Ca2+, and Mg2+ is achieved due to the matched Li+ ion diameter with the pocket/channel sizes and lower energy barrier for dehydration. Thus, this work proposes a feasible strategy for the construction of novel MOFs for ions adsorption.

A 3D Macroporous Carbon NiCu Single‐Atom Catalyst for High Current Density CO2 Electroreduction

AbstractTransition metal and nitrogen co‐decorated carbon materials are promising platforms for CO2 electroreduction. A hard‐template 2‐step pyrolysis method is proposed for the fabrication of highly dispersed Ni and Cu atomic active sites on a 3D macroporous carbon matrix. The pyrrolic N‐type Ni−Nx sites serve as dominant active sites toward selective CO2 electroreduction to CO. The incorporation of Cu alters the distribution of N species and simultaneously optimizes the electronic state and geometric structure of the Ni−Nx moiety, thereby improving its adsorption and activation capacity for CO2. Moreover, the isolated Cu atomic sites enhance the resistance of corresponding gas‐diffusion electrodes against electrolyte flooding. The optimal catalyst 3D NiCu‐69 achieves nearly exclusive production of CO with a Faraday efficiency (FECO) of 98% at a current density of −700 mA cm−2 in a CO2‐gas‐fed flow‐through electrolyzer and delivers a CO production rate of 1363 mol(m2s)−1, which is exceeding most reported electrocatalysts. The FECO remained as high as 94% after electrolyzing at a current density of −100 mA cm−2 for 22 h. 3D NiCu‐69 exhibits a favorable performance in both acidic and neutral conditions, with a high FECO of ≈90.2% within the current density range of −100 to −500 mA cm−2.

Dual function antioxidant and anti-inflammatory fish maw peptides: Isolation and structure-activity analysis via tandem molecular docking and quantum chemical calculation

The structure–function relationship of gastrointestinal tract digestion-derived fish maw peptides remains largely unknown. This study aims to elucidate the active sites and cellular bioactivities of these peptides through molecular docking (MD), density functional theory (DFT) computations, in silico bioinformatic analysis, and in cellulo Caco-2 cell studies. In silico screening identified 29 non-toxic, non-allergenic, and water-soluble peptides. Seven peptides exhibited favorable binding to the Keap1-Kelch (2FLU) and TNF-α (2AZ5) proteins. Specifically, peptides WIDPNQG, GFPGER, and FLLFRQ demonstrated the highest electron affinities and smallest HOMO-LUMO energy gaps, suggesting strong free-radical scavenging potential. Both DFT and ex situ MD confirmed the active sites of the seven peptides. The guanidinium group was the dominant active site on six peptides. The isolated peptides improved cellular redox balance, reduced malonaldehyde, and suppressed inflammatory cytokines. This study confirmed DFT computations as a novel tool for elucidating the structure-function relationship of food-derived peptides.

Dexamethasone is a regulator of clock genes in testicular peritubular cells.

We recently found that peritubular cells of the human testis are a dominant site of expression of the glucocorticoid receptor (GR; encoded by NR3C1). Activation of GR by dexamethasone (Dex) strongly influences the phenotype of cultured human testicular peritubular cells (HTPCs), causing massive changes of their proteome and secretome. As glucocorticoids (GC) are also known to set the internal clock of peripheral organs by regulating clock genes, we tested such an influence of Dex in HTPCs. We performed cellular studies with HTPCs and immortalized nonhuman primate (Callithrix jacchus; Cj)-derived peritubular cells, organotypic incubations of testicular fragments of Cj, qPCR and proteomic, as well as immunohistochemical studies. Basal clock gene expression levels, when monitored by qPCR under standard culture conditions, showed alterations over 24 h, suggesting an endogenous circadian rhythm, especially for BMAL1. Dex (1 µM) when added to cells, caused a strong and significant increase of PER1, followed by elevations of BMAL1, and other clock genes. This action was observed as early as 4 h after the addition of Dex. Immunohistochemistry and data mining revealed GR in testicular peritubular cells and other somatic cells of Cj, in situ. We therefore performed organotypic incubations of testicular fragments of Cj (n = 3) and found that upon addition of Dex (1 µM), mRNA levels of BMAL1 and PER1 also increased in samples of two out of three animals after 6 h. Mass spectrometry did, however, not reveal significant alterations of the testicular proteome, possibly due to the short time point and/or the fact that the somatic GR-expressing cells represent only a small portion of the testis. In support for this assumption, Dex (1 µM; 6 h) significantly increased mRNA levels of BMAL1 and PER1 in Cj-derived immortalized testicular peritubular cells. The results indicate that an internal clock system likely exists in peritubular cells of the testis and that Dex, via testicular GR expressed by peritubular cells and other somatic cells, is a strong regulator of this system. In a physiological situation, GC thus may be important regulators of the testicular clock, while in a situation of prolonged stress or GC-medication, derangements in clock gene expression may result.

Modification of Cs/SiO2 with Zr element through sol–gel method for production of methyl methacrylate via one-step aldol condensation

Development of effective cesium-based catalyst is important for methyl methacrylate (MMA) production via one-step aldol reaction. Herein, a kind of Cs/Zr-SiO2 catalyst was prepared by sol–gel method and the acid-base properties and their balance could be controllably regulated. The influence of catalyst preparation conditions including Si/Zr ratio and water content on the structure and acid-base properties of Cs/Zr-SiO2 was demonstrated, which consequentially affected catalytic performance. The formation of Si-O-Zr and Cs-O-Si structure was identified as the dominant Lewis acid and base sites and the acid site density can be enhanced by 1-fold when using sol–gel method. In addition, the MP conversion could reach 37 % with MMA selectivity of 85 % at the optimal condition. Kinetic studies revealed that the activation barrier on the modified 10Cs/Zr-SiO2 exhibited the lowest activation energy of 110.9 kJ/mol. Besides, the initial catalytic activity could still maintain after 800 h recycling, with single-pass life of 160 h.

Glycation of sunnhemp protein with dextran via dry heating: Thermal, micro-structural characterization, and amino acid profiling.

This study aims to obtain sunnhemp protein isolate (SHPI) and dextran conjugates by dry heating method of Maillard conjugation. The effects of different incubation time (0, 1, 3, 5, 7, and 9 days) on the molecular flexibility, available lysine content, antioxidant properties, molecular structure, and thermal and micro-structural properties of conjugates were compared with SHPI (no conjugation) at 60°C and 79% relative humidity. The results indicated the formation of SHPI-dextran conjugates as confirmed by the change in molecular flexibility, lysine content, antioxidant activities, color, and water activity values. The molecular structure revealed the confirmation of covalent bonding between SHPI and dextran. Differential scanning calorimetry and thermo-gravimetric analysis results exhibited improvement in the thermal stability of SHPI when conjugated with dextran. The microstructural characterization showed that Maillard conjugation changed the surface structure of SHPI. The analysis of amino acid composition displayed that lysine, arginine, and phenylalanine were the dominant Maillard reaction sites of SHPI and dextran. Among all the conjugated samples, 5 days of incubation time was selected as an optimum condition for the development of SHPI-dextran conjugates on the basis of the aforementioned characterization. Overall, it was concluded that Maillard conjugation of sunnhemp protein with dextran via dry-heating technique could modify and improve its various attributes. PRACTICAL APPLICATION: The conjugation of plant proteins with polysaccharide through the Maillard reaction under dry heating conditions represents a natural and green technique for improving the techno-functional properties of proteins. The study has the potential to establish framework for the utilization of Sunnhemp protein isolate-dextran conjugates. This approach offers the potential for cost-effective production of emulsifiers and development of effective encapsulating matrices. The investigation expands on an underutilized plant protein source facilitating an alternative to animal-based proteins and contributing to the development of a sustainable circular bioeconomy.

Hierarchically Ordered Pore Engineering of Carbon Supports with High-Density Edge-Type Single-Atom Sites to Boost Electrochemical CO2 Reduction.

Metal sites at the edge of the carbon matrix possess unique geometric and electronic structures, exhibiting higher intrinsic activity than in-plane sites. However, creating single-atom catalysts with high-density edge sites remains challenging. Herein, the hierarchically ordered pore engineering of metal-organic framework-based materials to construct high-density edge-type single-atomic Ni sites for electrochemical CO2 reduction reaction (CO2RR) is reported. The created ordered macroporous structure can expose enriched edges, further increased by hollowing the pore walls, which overcomes the low edge percentage in the traditional microporous substrates. The prepared single-atomic Ni sites on the ordered macroporous carbon with ultra-thin hollow walls (Ni/H-OMC) exhibit Faraday efficiencies of CO above 90% in an ultra-wide potential window of 600mV and a turnover frequency of 3.4×104h-1, much superior than that of the microporous material with dominant plane-type sites. Theory calculations reveal that NiN4 sites at the edges have a significantly disrupted charge distribution, forming electron-rich Ni centers with enhanced adsorption ability with *COOH, thereby boosting CO2RR efficiency. Furthermore, a Zn-CO2 battery using the Ni/H-OMC cathode shows an unprecedentedly high power density of 15.9mW cm-2 and maintains an exceptionally stable charge-discharge performance over 100h.

First-principles density functional study of iodine molecule adsorption on stable CuS surfaces

The present work investigated the adsorption of gaseous iodine molecules (I2) on stable CuS surface, which has demonstrated excellent performance as an adsorbent for I2 removal, with first-principles density functional theory (DFT). In this work, a pair of asymmetric surfaces (marked as slab1 and slab2) formed by breaking the weakest bond along (001) direction are chosen to present CuS surfaces. The findings indicate that the adsorption of I2 molecules on the pristine CuS(001) surface is relatively weak, while surface defects significantly enhance the binding strength of I2. In particular, S-vacancy CuS(001) surfaces exhibit considerably higher adsorption energy for I2 compared to Cu-vacancy surfaces. We found that the hollow and Cu-top sites are typically the dominant adsorption sites, and the initial orientation of I2 relative to the surface also influences the adsorption performance.

Development of Polymorphic Index Model for Assessing Subtropical Secondary Natural Oak Forest Site Quality Under Complex Site and Climate Variables

Site and climate conditions are the key determinants controlling dominant height growth and forest productivity, both independently and interactively. Secondary natural oak forests are a typical forest type in China, especially in Hunan Province, but little is known about the site index of this forest under the complex site and climate variables in the subtropics. Based on survey data of dominant trees and site variables from 101 plots in Hunan oak natural secondary forests and climate data obtained using spatial interpolation, we used the random forest method, correlation analysis, and the analysis of variance to determine the main site and climate factors affecting oak forest dominant height and proposed a modeling method of an oak natural secondary forest site index based on the random effect of site–climate interaction type. Of the site variables, elevation affected stand dominant height the most, followed by slope direction and position. Winter precipitation and summer mean maximum temperature had the greatest impact on stand dominant height. To develop the modeling method, we created 10 popular base models but found low performance (R2 ranged from 0.1731 to 0.2030). The optimal base model was Mitscherlich form M3 (R2 = 0.1940) based on parameter significance tests. Since site and climate factors affect the site index curve, the dominant site and climate factors were combined into site types and climate types, respectively, and a nonlinear mixed-effects approach was used to simulate different site types, climate types, site–climate interaction types, and their combinations as random effects. Site–climate interaction type as a random factor enhanced model (M3.4) performance and prediction accuracy (R2 from 0.1940 to 0.8220) compared to the optimum base model. After clustering the 62 site–climate interaction types into three, five, and eight groups using hierarchical clustering, a mixed-effects model with the random effects of eight groups improved model performance (R2 = 0.8265) and applicability. The modeling method developed in this study could be used to assess a regional secondary natural oak forest site index under complex site and climate variables to evaluate the forest productivity.

High-Valence Metals Accelerate the Reaction Kinetics for Boosting Water Oxidation.

The transition metal with high valence state in oxyhydroxides can accelerate the reaction kinetics, enabling highly intrinsic OER activity. However, the formation of high-valence transition-metal ions is thermodynamically unfavorable in most cases. Here, a novel strategy is proposed to realize the purpose and reveal the mechanism by constructing amorphous phase and incorporating of elements with the characteristic of Lewis acid or variable charge state. A model catalyst, CeO2-NiFeOxHy, is presented to achieve the modulation of valence state of active site (Ni2+→Ni3+→Ni4+) for improved OER, leading to dominant active sites with high valence state. The CeO2-NiFeOxHy electrode exhibits superior OER performance with overpotential of 214 and 659mV at 10 and 500mAcm-2, respectively (without IR correction), and high stability, which are much better than those of NiOxHy, NiFeOxHy and CeO2-NiOxHy. These findings provide an effective strategy to achieve the active metals with high-valence state for highly efficient OER.