Substitution Sites Research Articles

Impact of vascular Ehlers-Danlos Syndrome-associated Gly substitutions on structure, function, and mechanics using bacterial collagen.

Vascular Ehlers-Danlos syndrome (vEDS) arises from mutations in collagen-III, a major structural component of the extracellular matrix (ECM) in vascularized tissues, including blood vessels. Fibrillar collagens form a triple-helix that is characterized by a canonical (Gly-X-Y)n sequence. The substitution of another amino acid for Gly within this conserved repeating sequence is associated with several hereditary connective tissue disorders, including vEDS. The clinical severity of vEDS depends on the identity of the substituted amino acid and its location. In this study, we engineered recombinant bacterial collagen-like proteins (CLPs) with previously reported Gly→X (X=Ser or Arg) vEDS substitutions within the integrin-binding site. Employing a combination of biophysical techniques, enzymatic digestion assays, integrin binding affinity assays, and computational modeling, we assessed the impact of Gly→X substitutions on structure, stability, function, and mechanical properties. While constructs with Ser or Arg substitutions maintained a triple-helix structure, Arg substitution significantly reduced global thermal stability, heightened susceptibility to trypsin digestion, and altered integrin α2-inserted (α2I) domain binding. Molecular dynamics (MD) simulations also demonstrated distinct effects of different Gly substitutions on the triple-helix structure - Arg substitutions induced notable bulging at the substitution site and disrupted interchain hydrogen bonds compared to Ser substitutions. Additionally, steered MD simulations revealed that Arg substitution led to a significant decrease in Young's modulus of the triple-helix. Bacterial CLPs have proved to be a powerful model for studying the underlying mechanisms of vEDS-causing mutations in collagen-III. Serine and arginine substitutions differentially perturb cell-matrix interactions and ECM in a manner consistent with clinical vEDS severity.

A PLIN1 polymorphism is associated with fat production in male emus

The emu (Dromaius novaehollandiae) is a novel poultry species that produces meat, eggs, and fat. Although emus have recently been domesticated, genetic improvements to establish strains have scarcely progressed. In this study, we investigated the relationship between production traits and perilipin 1-encoding gene (PLIN1) polymorphisms in the emus. We determined the partial complementary DNA (cDNA) sequence of the PLIN1, which is involved in lipid droplet formation. We identified four nucleotide substitution sites (c.270C>T, c.321T>C, c.587A>T, and c.639C>T) in the PLIN1 gene of emus. Of these, c.587A>T is a non-synonymous substitution that converts lysine to methionine at the 196th codon (p.K196M). Although p.K196M was predicted to affect the production traits of emus, a large deflection in genotype frequency was observed in this study; thus, we could not investigate the relationship between genotypes and phenotypes. In males, the fat yields of the CC, CT, and TT genotypes in c.270C>T were 0.25 ± 0.06, 0.22 ± 0.06, and 0.21 ± 0.07 kg, respectively, while the meat yields of the CC, CT, and TT genotypes in c.270C>T were 0.15 ± 0.01, 0.16 ± 0.02, and 0.16 ± 0.03 kg, respectively. These results indicate that male emus with the CC genotype had a significantly higher fat content and lower meat productivity than male emus with the other genotypes (P < 0.05). Therefore, c.270C>T in PLIN1 affects fat and meat production in males. Our findings may contribute to the effective genetic improvement of the emus.

Molecular Design of n-Type Organic Semiconductors with Ultralow Electron Reorganization Energies.

Bottom-up design of n-type organic semiconductors with salient electron-transport properties is of fundamental importance. Here, with the aid of density functional theory, we demonstrate that condensing odd-membered carbon rings (5MR/7MR) to small polycyclic aromatic hydrocarbons (PAHs) can endow molecules with ultralow electron reorganization energies (λ < 100 meV). Studying 60 molecules, we find that introducing polycyclic fragments with built-in 5MR and 7MR to linear PAHs at the Cα,β positions or to nonlinear PAHs in D2h symmetry constitutes molecules with λ as low as 65 meV. A joint ACID and NICS analysis proves that the stronger the molecular aromaticity, the lower the λ will be. This is contrary to what has been previously found for p-type molecules. Furthermore, we propose "acupoints" on molecules for N-doping and cyanation, which can be used to precisely locate the substitution sites to reduce the LUMO energies (in favor of electron injection and air stability) of low-λ molecules while it does not elevate λ. These findings would help to reduce the synthetic blindness/cost and contribute to the bottom-up design of n-type small-molecule organic semiconductors.

Heteroatom Effect on Site-Selective Oxygen-Sulfur Substitution Reactions of Keggin-Type Polyoxotungstates.

Sulfur, a group 16 element, can substitute the oxygen sites of metal oxides, potentially providing them with unique properties and enabling new applications. Polyoxometalates (POMs) are anionic metal oxide clusters with wide structural diversity owing to arbitrary selection of their constituting metal atoms. However, substitution of the oxygen sites of POMs with sulfur atoms has been rarely explored. Recently, we reacted a Keggin-type POM [XW12O40]4- (IX; X = Si and Ge) with a sulfurizing reagent (Lawesson's reagent), synthesizing Keggin-type polyoxothiometalates (POTMs) [XW12O28S12]4- (IIX, X = Si and Ge) in which all 12 terminal oxygen atoms of IX were site-selectively substituted with sulfur atoms. Although the selected heteroatoms (X) and anion charges substantially influence the properties and reactivities of POMs, oxygen-sulfur substitution of Keggin-type POMs with other heteroatoms and anion charges has not been attempted. Herein, we report the oxygen-sulfur substitution reaction of Keggin-type POMs [XW12O40]n- (IX; X = Al, Si, and P; n = 5, 4, and 3, respectively) with various heteroatoms, yielding the corresponding Keggin-type POTMs [XW12O28S12]n- (IIX). The oxygen-sulfur substitution reaction depended on the heteroatom: POMs with higher anion charges reacted more strongly with the sulfurizing reagents. We also investigated the reaction mechanism of POMs and sulfurizing reagents.

Structure-performance relationship and molecular structure optimization design of acid phosphate ester extractants

The extraction performance of acid phosphate ester extractants (PEEs) decreases significantly as the acidity of the aqueous phase increases. Therefore, finding PEEs suitable for high-acid environments has become critical to addressing their performance attenuation. However, the unclear structure-performance relationship of PEEs has led to a lack of guidance in experimental synthesis, significantly impeding the emergence of new acid-resistant PEEs. To tackle these issues, ten novel phenyl phosphate ester extractants were designed based on the molecular formula of phosphodiester (R1R2P(=O)OH) and the conjugation effect of the benzene ring. The relationship between the intrinsic extraction performance of acid PEEs and substituent groups (phenoxy, alkoxy, and alkyl) was quantitatively established by calculating the Gibbs free energy changes of three primary reactions (dimer dissociation, monomer acid ionization, and metal coordination) during divalent cobalt ion extraction. Additionally, the impact of different substitution sites (para, meta, and ortho) of the benzene ring on the extraction performance of acid PEEs was studied. The results indicated that introducing phenoxy groups into traditional acid PEEs (P204 and P507) can effectively enhance the extractants’ acid ionization ability and thermodynamic driving force. The extraction performance of acid PEEs is positively correlated with the number of phenoxy groups, and carbon chain substitution at the meta-position of the benzene ring is the most advantageous. By screening five low-toxicity and low-cost phenolic hydroxyl reagents currently available on the market, design a phenyl phosphate ester extractant ([(CH3)3CCH2C(CH3)2C6H4O]2P(=O)OH, P-4TO) that combines cost and performance advantages. Furthermore, the transition state theory was used to confirm the feasibility of preparing P-4TO, which provided a comprehensive theoretical research method for the future design and synthesis of efficient PEEs.

Importing Atomic Rare‐Earth Sites to Activate Lattice Oxygen of Spinel Oxides for Electrocatalytic Oxygen Evolution

AbstractSpinel oxides have emerged as highly active catalysts for the oxygen evolution reaction (OER). Owing to covalency competition, the OER process on spinel oxides often follows an arduous adsorbate evolution mechanism (AEM) pathway. Herein, we propose a novel rare‐earth sites substitution strategy to tune the lattice oxygen redox of spinel oxides and bypass the AEM scaling relationship limitation. Taking NiCo2O4 as a model, the incorporation of Ce into the octahedral site induces the formation of Ce−O−M (M=Ni, Co) bridge, which triggers charge redistribution within NiCo2O4. The developed Ce−NiCo2O4 exhibits remarkable OER activity with a low overpotential, satisfactory electrochemical stability, and good practicability in anion‐exchange membrane water electrolyzer. Theoretical analyses reveal that OER on Ce−NiCo2O4 surface follows a more favorable lattice oxygen mechanism (LOM) pathway and non‐concerted proton‐electron transfers compared to pure NiCo2O4, as also verified by pH‐dependent behavior and in situ Raman analysis. The 18O‐labeled electrochemical mass spectrometry provides direct evidence that the oxygen released during the OER originates from the lattice oxygen of Ce−NiCo2O4. We discover that electron delocalization of Ce 4f states triggers charge redistribution in NiCo2O4 through the Ce−O−M bridge, favoring antibonding state occupation of Ni−O bonding in [Ce−O−Ni] unit site, thereby activating lattice oxygen redox of NiCo2O4 in OER. This work provides a new perspective for designing highly active spinel oxides for OER and offers significant insights into the rare‐earth‐enhanced LOM mechanism.

Importing Atomic Rare-Earth Sites to Activate Lattice Oxygen of Spinel Oxides for Electrocatalytic Oxygen Evolution.

Spinel oxides have emerged as highly active catalysts for the oxygen evolution reaction (OER). Owing to covalency competition, the OER process on spinel oxides often follows an arduous adsorbate evolution mechanism (AEM) pathway. Herein, we propose a novel rare-earth sites substitution strategy to tune the lattice oxygen redox of spinel oxides and bypass the AEM scaling relationship limitation. Taking NiCo2O4 as a model, the incorporation of Ce into the octahedral site induces the formation of Ce-O-M (M=Ni, Co) bridge, which triggers charge redistribution within NiCo2O4. The developed Ce-NiCo2O4 exhibits remarkable OER activity with a low overpotential, satisfactory electrochemical stability, and good practicability in anion-exchange membrane water electrolyzer. Theoretical analyses reveal that OER on Ce-NiCo2O4 surface follows a more favorable lattice oxygen mechanism (LOM) pathway and non-concerted proton-electron transfers compared to pure NiCo2O4, as also verified by pH-dependent behavior and in situ Raman analysis. The 18O-labeled electrochemical mass spectrometry provides direct evidence that the oxygen released during the OER originates from the lattice oxygen of Ce-NiCo2O4. We discover that electron delocalization of Ce 4f states triggers charge redistribution in NiCo2O4 through the Ce-O-M bridge, favoring antibonding state occupation of Ni-O bonding in [Ce-O-Ni] unit site, thereby activating lattice oxygen redox of NiCo2O4 in OER. This work provides a new perspective for designing highly active spinel oxides for OER and offers significant insights into the rare-earth-enhanced LOM mechanism.

Molecular dynamics simulation: Effect of sulfation on the structure of curdlan triple helix in aqueous solution

In this work, by using molecular dynamics simulations, we elucidate the effect of sulfation substitution on the stability of the curdlan triple helix structure. The simulation results indicate that the stability of the triple helix structure is significantly influenced by the sites of sulfation substitution. The substitution at the O2 site directly disrupts the hydrogen bonding network between the triple helix chains, significantly destroying the triple helix conformation. When substitutions occur at both the O4 and O6 sites simultaneously (O4,6), the electrostatic repulsion between numerous sulfate groups introduces considerable energy perturbation to the triple helix, leading to alterations in the glucan chain conformation and consequent destabilization of the triple helix structure. Meanwhile, we find that even if the sulfation substitution is performed at the same substitution sites, the difference in the degree of substitution also has an impact on the triple helix stability. The resistance of the triple helix to sulfation substitution at O2 is weak, and low degree of substitution can lead to the unwinding of the triple helix. However, it demonstrates higher resistance to substitution at O4,6 where only higher degree of substitution results in triple helix destabilization.

High-throughput screening and identification of lignin peroxidase based on spore surface display of Bacillus subtilis.

Lignin peroxidase is closely related to agriculture and food as it improves the quality of feedstuffs, facilitates the degradation of lignin in agricultural wastes, and degrades azo dyes that have similar complex structures to lignin. However, the current status of homologous or heterologous expression of lignin peroxidase is unsatisfactory and needs to be modified with the help of immobilization and directed evolution to maximize its potential. Directed evolution technology is an effective strategy for designing and improving enzyme characteristics, and Bacillus subtilis spore surface display technology is an efficient method for preparing immobilized enzymes. A colorimetric dye decolorization assay using Congo red as a substrate was developed and optimized for high-throughput screening of spore surface display in a 96-well plate. After two rounds of screening, a superior mutant strain was selected from 2700 mutants. Its highest catalytic activity was 196.36%. The amino acid substitution sites were identified as N120D and I242T. The mechanism for the enhanced catalytic activity was explained using protein modeling and functional analysis software. This study provides insights into the rational design of lignin peroxidase and its application in food and agriculture. © 2024 Society of Chemical Industry.

Loss of heterozygosity of CYP2D6 enhances the sensitivity of hepatocellular carcinomas to talazoparib

Loss of heterozygosity (LOH) diminishes genetic diversity within cancer genomes. A tumour arising in an individual heterozygous for a functional and a loss-of-function (LoF) allele of a gene occasionally retain only the LoF allele. This can result in deficiency of specific protein activities in cancer cells, creating unique differences between tumour cells and normal cells of the individual. Such differences may constitute vulnerabilities that can be exploited through allele-specific therapies. To discover frequently lost genes with prevalent LoF alleles, we mined the 1000 Genomes dataset for SNVs causing protein truncation through base substitution, indels or splice site disruptions, resulting in 60 LoF variants in 60 genes. From these, the variant rs3892097 in the liver enzyme CYP2D6 was selected because it is located within a genomic region that frequently undergoes LOH in several tumor types including hepatocellular cancers. To evaluate the relationship between CYP2D6 activity and the toxicities of anticancer agents, we screened 525 compounds currently in clinical use or undergoing clinical trials using cell model systems with or without CYP2D6 activity. We identified 12 compounds, AZD-3463, CYC-116, etoposide, everolimus, GDC-0349, lenvatinib, MK-8776, PHA-680632, talazoparib, tyrphostin 9, VX-702, and WZ-3146, using an engineered HEK293T cell model. Of these, talazoparib and MK-8776 demonstrated consistently heightened cytotoxic effects against cells with compromised CYP2D6 activity in engineered hepatocellular cancer cell models. Moreover, talazoparib displayed CYP2D6 genotype dependent effects on primary hepatocellular carcinoma organoids. Exploiting the loss of drug-metabolizing enzyme gene activity in tumor cells following loss of heterozygosity could present a promising therapeutic strategy for targeted cancer treatment. This work was funded by Barncancerfonden (T.S, PR2022-0099 and PR2020-0171, X.Z, TJ2021-0111), Cancerfonden (T.S, 211719Pj and D.G, 222449Pj), Vetenskapsrådet (T.S, 2020-02371 and D.G, 2020-04707), and the Erling Persson Foundation (T.S, 2020-0037 and T.S, 2023-0113).

Valence switching of bismuth in ferricyanide as cathode materials for sodium-ion batteries

Sodium-ion batteries (SIBs) are considered potential alternatives to lithium-ion batteries, and the key to their widespread use lies in finding efficient and cost-effective cathode materials. Ferricyanides have emerged as promising candidates for SIBs cathodes due to their low cost and open channel structure allowing for favorable ion and electron transport. However, traditional ferricyanides such as Prussian blue (PB) and its analogs (PBAs) have a limited two-electron transfer capacity, which hampers their practical application. Bi-based ferricyanide materials with multiple valence states, low toxicity and abundant resources are attractive for electrochemical reactions and enable multiple electron transfers to develop high-capacity cathode materials. In this study, we synthesized a rod-like BiHCF·4H2O sample using a simple coprecipitation method. After dehydration, the rod-like BiHCF compounds with a robust framework and reduced lattice water defects demonstrated good electrochemical performance in SIBs. The rod-like BiHCF electrode exhibited a specific capacity of 221 mAh g−1 at 20 mA g−1 based on a three-electron transfer of Bi3+/Bi0. A full SIBs composed of a BiHCF cathode and Bi anode demonstrated acceptable performance, indicating potential for practical applications. This work provides valuable insights into the development of redox-active site substitution strategies for high performance positive electrode materials in SIBs.

Energy trapping to substitutional and charge compensation defects in persistent luminescent BaAl2O4:Tb3+

The holistic approach of the photoluminescence (PL), thermoluminescence (TL), and persistent luminescence properties at room temperature of BaAl2O4:Tb3+ were investigated in detail using a wide range of techniques. Materials were obtained using a solution combustion synthesis. The x-ray powder diffraction patterns of nondoped and Tb3+ doped BaAl2O4 indicated the hexagonal phase, and a Tb4O7 solid solution was observed at 4 and 5 mol% Tb doped aluminate. X-ray photoelectron spectroscopy revealed that Ba occupied one site and that Tb ions occupied this site as Tb3+ as well as TbIV. PL emission in blue, green, and red was observed under an excitation at 228 nm, that originated from the interconfigurational 4f8–4f75d1 transitions of Tb3+. Time-of-flight secondary ion mass spectroscopy, UV–vis diffuse reflectance, and PL revealed the presence of a Cr3+ impurity. The 0.5 mol% Tb3+ doped BaAl2O4 exhibited a strong TL band at 354, 437 and 598 K, which were attributed to the traps formed by Tb3+ doping and subsequent O2− charge compensation. A persistent luminescence mechanism was constructed for the Tb3+ doped BaAl2O4. After the energy was stored in thermally liberated Tb3+ in the Ba2+ substitution sites and charge compensation defects, the Tb3+ was the source of the continuous luminescence.

The livelihood impacts of eucalypt plantations on rural farm households in Western Gurage Watersheds, Central-south Ethiopia

BackgroundRural landscapes, particularly those close to human settlements and main roads throughout the highlands of Ethiopia, appear greener than the outfields because of eucalypt plantations. The most common factors for eucalypt plantations are two: fuel and construction demands and to generate income. ObjectiveThis study tried to investigate the socioeconomic impacts of eucalypt plantations in Western Gurage Watersheds located in Central-south Ethiopia. The specific objectives are: to evaluate the socioeconomic importance of eucalypt plantations on the livelihood of farm households, and to assess perceptions on impacts of eucalypt plantation and copping strategies. MethodsSystematic and purposive sampling method was employed by selecting households with eucalypt woodlots from the list of each Woreda's Kebeles. Close- and open- ended questionnaires were distributed to every fifth households that possessed eucalypt plantations. Three hundred eighty three questionnaires were distributed and collected from households found in three Woredas (districts) namely Cheha, Enemorna Ener, and Eza located in the Watersheds. To supplement the information critical observations, discussions with focus groups and interviews with key informant were employed. The survey data were analyzed using both qualitative and quantitative techniques. To describe data acquired from critical observations, focus group discussions and key informant interviews; critical and logical qualitative data analysis technique were used. Descriptive and dispersive statistics such as frequency, percentage, mean, variance, standard deviation, p- value and correlation were employed using SPSS Version 20. ResultsThe result showed that eucalypt plantation dominated fuel wood and construction consumption and substituted further encroachment to natural forests. From multiple responses given, households prefer planting eucalypts to indigenous trees because it is fast growing (100 %), profitable (100 %), needs lesser labor (100 %), needs lower capital (100 %), can be used for multipurpose (100 %), and coppice itself fatly (93 %). They rated income gained from eucalypt as 2nd next to enset. ConclusionsHouseholds may continue planting the species particularly for fuel wood and construction need since substituting it by other alternative seems not feasible and challenging. To sustain the livelihood and environment; appropriate management like site selection and substitutions by horticultural and cash crops using micro irrigation schemes for market needs are recommended. Conducting in-depth participatory research and specific policy ratification and promulgation on eucalypt plantations will sustain its utilization and curb the drawbacks.

Surface segregation on Ag@MNi (M = Pd, Pt, Rh, and Ru) core–shell nanocrystals for enhancing the oxygen reduction performance

Synthesis of cost-effective electrocatalysts for oxygen reduction reaction (ORR) has received wide attention due to their sluggish kinetics, which limits the development and application of fuel cell technique. In this work, we report a versatile synthetic approach to prepare a series of small-sized Ag@MNi (M = Pd, Pt, Rh, Ru) nanocrystals with core–shell structures by a simple solvothermal method. According to characterization analysis, surface segregation of Pd was proved in the outermost layer with the Pd-rich shell layer, which can regulate the adsorption energy of *OH. Electrochemical results show that the onset potential and half-wave potential of Ag@PdNi nanocrystals (Ag@PdNi NCs) are 1.005 and 0.913 V vs. RHE (reversible hydrogen electrode), respectively, with a Tafel slope of 55.31 mV dec-1 and strong ORR catalytic durability, which is similar to Ag@MNi (M = Pt, Rh, Ru) NCs and slightly higher than that of PdAg alloy nanoparticles (PdAg alloy NPs), PdNi alloy nanoparticles (PdNi alloy NPs), commercial Pd black and even commercial Pt/C, in alkaline medium. Density Functional (DFT) calculations show that the presence of Agcore effectively promotes the segregation of Pd atoms to the outer shell surface, where Ni provides better segregated substitution sites for Pd, which significantly improves the ORR activity and durability due to the electronic synergistic effect between Agcore nuclei and Pdshell can reduce the adsorption strength of OHads.

Design, synthesis and biological evaluation of sulfonylurea derivatives as NLRP3 inflammasome inhibitors

The NLRP3 inflammasome has been extensively studied in recent years and its aberrant activation can exacerbate inflammatory responses, contributing to various diseases. MCC950, a sulfonylurea drug, is a potent selective inhibitor of the NLRP3 inflammasome. However, its clinical development was halted due to hepatotoxicity, and studies have indicated significant reduction in activity among its metabolites. Building upon MCC950, we referenced substitution sites of NP3-146 for structural modifications aimed at addressing potential metabolism-related issues. Consequently, we synthesized a series of sulfonylurea derivatives. Ultimately, the optimized compound C4 exhibited a remarkable 80.39 % inhibition of IL-1β at 2 μM, with an IC50 value of 0.805 μM. In conclusion, compound C4 shows potential as a lead compound and warrants further development as an anti-inflammatory NLRP3 inhibitor.

Ancient and modern bone diagnosis: Towards a better understanding of chemical and structural feature alterations

Chemical and structural alterations hold great importance in the field of diagenesis. Attenuated Total Reflectance − Fourier Transform Infrared Spectroscopy (ATR-FTIR) is a valuable method for examining bio-apatite composition changes. Infrared spectroscopy (IR) and X-ray diffraction (XRD) were employed to analyze both modern and archaeological bone specimens. Organic and mineral component changes in modern and ancient samples were investigated. Ancient bone samples were collected from two archaeological sites in Jordan, dating back to the Iron and Byzantine ages. IR results indicated that collagen cross-links and mineral maturity are higher in modern bones compared to ancient bones. Additionally, the crystallinity index is higher in modern bones than in archaeological bones, while the carbonate to phosphate ratio (C/P) is lower in modern bones than in ancient ones. Curve fitting was applied to reveal the carbonate substitution inside the hydroxyapatite lattice within the IR region from 850 to 890 cm−1. A2-type carbonates (identified as υ2 of CO32−) denote hydroxyl site substitution, and B-type carbonates represent a substitution to the phosphate site. The full width at half maximum (FWHM) of the peak at 604 cm−1 from IR spectra reveals that crystallinity is higher in modern bones, as confirmed by the FWHM of the (002)-apatite pattern in XRD. Statistical analysis was conducted to validate these findings, ensuring the robustness of the results. Finally, the results obtained in this investigation align with previous literature reports regarding ATR-FTIR ratios. This suggests that modern bones have better crystallinity compared to ancient bones. Furthermore, the ATR-FTIR ratios indicate that the hydroxyl and phosphate sites of modern bones undergo more substitution than older bones. The findings of this study not only enhance our understanding of the diagnostic processes in archaeological bone specimens but also have broader implications for fields such as archaeology, anthropology, and forensics, where the analysis of bone composition and structural changes can provide valuable insights into the history and characteristics of ancient remains.

Evaluating Sulfur as a P‐Type Dopant in Cu3N Using Ab Initio Methods

Copper nitride (Cu3N) is an environmentally friendly semiconducting material with bipolar doping capability and is of interest to various applications. As deposited Cu3N films have inherent n‐type conductivity, further controllable n‐type doping is possible by introducing metal impurities. First‐principles methods based on density functional theory and beyond have been employed to study the p‐type doping behavior of sulfur atoms in Cu3N. The structural, electronic, optical, and thermal properties of pure Cu3N and sulfur‐doped Cu3N are computed for single and 3 × 3 × 3 supercells. Sulfur doping causes a shift from intrinsic n‐type to p‐type behavior. This study confirms that sulfur atoms in sulfur‐doped copper nitride preferentially occupy interstitial positions over nitrogen substitution, face‐centered, or copper substitution sites. Due to this change and an increased lattice constant, Cu3N becomes a softer material with a larger bandgap in the single‐cell alloy. Doped Cu3N supercell results show significant changes in optical properties appropriate for solar and other photoelectric applications. Cu3N:S exhibits remarkable enhancements in power factor and thermal and electrical conductivity, indicating potentially better performance in thermoelectric applications. The dielectric constant and absorption coefficient also significantly change with the incorporation of sulfur into Cu3N.

Bifunctional catalytic activity of anion-doped LaSrCoO4 for oxygen reduction and evolution reactions.

Here, we synthesized Co-based, anion-incorporated‍ ‌R‌u‌d‌d‌l‌e‌s-d‌e‌n‌-‌Popper perovskite electrocatalysts (LaSrCoO4-x X y ) and compared their catalytic performances in the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The ORR mechanism with the newly synthesized F-doped LaSrCoO4 catalyst was dominated by a four-electron process, and the number of electrons involved in the reaction increased compared with that for LaSrCoO4. The OER activity of the hydride-doped LaSrCoO4 catalyst was the highest among the LaSrCoO4 system catalysts. Density functional theory calculations revealed that there is a correlation between the Co 3d unoccupied orbital band centre and the OER activity. The addition of anions and substitution of metal sites improved the ORR and OER activities of the catalysts. Our findings confirmed that the addition of heteroatom anions can improve the activity of perovskite-type electrocatalysts, promoting their application in various fields.

Substitution of Ce4+ for ionic at both A/B sites greatly improves the microwave responses of (Sr0.9Ca0.1)1/2La1/2Al1/2Ti1/2O3 perovskite ceramics

In this paper, (Sr0.9Ca0.1)1/2La1/2Al1/2Ti1/2O3-x wt.% CeO2 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) ceramics were synthesized via solid state reaction. The effects of Ce4+ doping on microstructure and microwave dielectric properties were studied. All samples crystallized as perovskite single-phase. Ce4+ substitution for La3+ occurred at the A site for 0 < x ≤ 0.4, and for Ti4+ at the B site for 0.4 ≤ x ≤ 0.5. Oxygen vacancy concentration was linked to substitution sites, decreasing for x ≤ 0.3 and increasing for x ≥ 0.4, as shown by XPS analysis. The quality factor was influenced by oxygen vacancies, grain size, and packing fraction. Bonding valence and oxygen octahedral distortion affected the temperature coefficient of resonant frequency. At x = 0.4 and sintered at 1570 °C, the ceramics showed excellent properties: εr = 38.83, Q×f = 54058 GHz, τf = 2.137 ppm/°C, making it a promising low-loss dielectric ceramic for microwave communication applications.

Halogenated-edge polymeric semiconductor for efficient spin transport.

Organic semiconductors (OSCs) are featured by weak spin-orbit coupling due to their light chemical element composition, which enables them to maintain spin orientation for a long spin lifetime and show significant potential in room-temperature spin transport. Carrier mobility and spin lifetime are the two main factors of the spin transport performance of OSCs, however, their ambiguous mechanisms with molecular structure make the development of spintronic materials really stagnant. Herein, the effects of halogen substitution in bay-annulated indigo-based polymers on carrier mobility and spin relaxation have been systematically investigated. The enhanced carrier mobility with an undiminished spin lifetime contributes to a 3.7-fold increase in spin diffusion length and a record-high magnetoresistance of 8.7% at room temperature. By analyzing the spin-orbit coupling and hyperfine interaction, it was found that the distance of the substitution site from the conjugated center and the nitrogen atoms in the molecules play crucial roles in spin relaxation. Based on the above results, we proposed a molecular design strategy of halogen substitution far from conjugate center to enhance spin transport efficiency, presenting a promising avenue for advancing the field of organic spintronics.