Effect Of Substitution Research Articles

Substitution effects in tourism and hospitality: influential factors, examples, and propositions

Substitution effects in tourism and hospitality: influential factors, examples, and propositions

Specific heat analyses on optical-phonon-derived uniaxial negative thermal expansion system TrZr2 (tr = fe and Co1- xNix).

A large uniaxial negative thermal expansion (NTE) along the c-axis has recently been observed in the transition metal (Tr) zirconides TrZr2 with a tetragonal CuAl2-type structure. A recent study on FeZr₂ [M. Xu et al., Nat. Commun. 14, 4439 (2023)] suggests that optical phonons play a critical role in inducing the NTE along the c-axis. In this study, we investigate the thermophysical properties of TrZr₂ compounds (Tr = Fe and Co1- xNix(x = 0, 0.2, 0.4, 0.6, 0.8, 1)) using specific heat measurements, sound velocity data, and theoretical phonon calculations to achieve our aim of clarifying the contribution of optical phonons to the uniaxial NTE along the c-axis observed in both FeZr₂ and CoZr₂. We found that FeZr2 shows a lattice-specific heat peak structure at 8.90 meV, which corresponds to optical phonon energy with a high population of negative Grüneisen parameter along the c-axis in the phonon dispersion curves in FeZr2. In an examination of a chemical substitution effect on the Co1- xNixZr2, we found that the lattice-specific heat peak structure disappeared for x ≥ 0.4 and the oscillator intensity decreased. Phonon calculations revealed the existence of low-energy optical phonon branches at the Γ point for CoZr2 and FeZr2 with uniaxial NTE along the c-axis. However, the low-energy phonon branches were not found in NiZr2 with uniaxial positive thermal expansion along the c-axis. The increase in phonon density of states near the above optical phonon energy in CoZr2 and FeZr2 is consistent with the lattice-specific heat analyses, and we propose that low-energy optical phonons are essential for the exhibiting of uniaxial NTE along the c-axis in TrZr2.

The relationship between insurance development, population, economic growth, and health expenditures in OECD countries: a panel causality analysis

AbstractThis paper examines the relationship between insurance development, population, economic growth, and health expenditures for a panel of 31 OECD countries over the period 1995–2021. A dynamic panel data analysis based on cointegration, FMOLS, DOLS, VECM, and Granger causality tests is employed to suggest for the existence of a long-run relationship among variables. The long-run results show that insurance development, national income, and population exhibit positive impacts on health expenditures. The results reveal that insurance factor has larger income effects than substitution effects on health expenditures. Regarding the short-run causal relationship between the variables, the empirical results suggest that economic growth strengthens health expenditure growth, while insurance growth reduces it. In the short-run, insurance development has a crowding-out effect since it produces larger substitution effects than income effects. The results provide political implications that governments need to concern the short-run crowding-out effect of private insurance sections on health expenditures when making fiscal policies on public health expenditures.

Analysis of candidate variants in a Chinese family with monozygotic twins with keratoconus: a case report

ABSTRACT Background Keratoconus (KC) is an asymmetrical bilateral corneal ectasia, of which the pathogenesis is unknown. Moreover, genetic factors play an important role. We reported ophthalmic findings in a Chinese family with monozygotic twins with KC to describe the clinical features and identify genetic variants. Methods Comprehensive ophthalmic clinical assessments and examinations, including history, slit-lamp biomicroscopy, best-corrected visual acuity, corneal topography, anterior segment optical coherence tomography, and corneal biomechanics, were carried out on the twins and their parents. Whole-genome sequencing (WGS) was performed to identify variants in this family. SIFT, PolyPhen2, MutationTaster, and CADD were used to predict the effect of amino acid substitutions on the affected protein. Results The twins presented typical KC features. However, their mother did not meet the criteria for a KC diagnosis but exhibited KC subclinical manifestations. After screening, 12 potentially pathogenic variants in 10 genes were identified in both twins and emerged as candidate variants for this family. These genes included 1 previously reported KC-associated variant (ZNF469, c.4384 G>A); 8 variants in 6 KC-associated genes (GRHPR, c.337 G>A, c.862_863del; COL6A1, c.920 G>A; FLG, c.8753C>G; HSPG2, c.9503C>T; KRT82, c.1306 G>A; SCN9A, c.5702_5706del, c.641 G>A); and 3 variants in 3 non-KC-associated genes (PDE6G, c.6C>A; HAL, c.1724C>T; AGBL1, c.2381 G>A). Conclusions The accumulation of these potentially pathogenic variants in twins may have caused KC in these twins. These results expand the spectrum of KC candidate variants and provide a basis for further studies on KC.

A Data-Driven Optimization Framework for Static Rebalancing Operations in Bike Sharing Systems

Bike sharing systems have been widely deployed in urban cities for first- and last-mile transportation. However, because of the geographical and temporal imbalance of bike demand, bikes need to be reallocated system-wide among stations during the night to maintain a high service level while minimizing demand loss due to stockout or overcapacity. Two technical challenges remain in optimizing the static bike rebalancing operations. One challenge is to accurately predict bike pickup and dropoff demand at each station, considering demand substitution effects and subsequently determining the optimal rebalancing quantity for each station. The other is to efficiently optimize the routing of multiple rebalancing vehicles for large-scale bike sharing systems, considering outlier stations with rebalancing quantities exceeding vehicle capacity. To this end, we propose an end-to-end solution to tackle the aforesaid challenges. Specifically, we first develop deep learning-based predictors that capture the time dependencies of station-level demand, the impact of weather conditions, and the demand substitution effect by nearby stations. Based on the demand rate, a sequential simulation-based demand loss estimator is developed to find the optimal rebalancing quantities that lead to the minimum expected demand loss. Then, a mixed integer linear programming model is formulated to optimize the routing problem of rebalancing vehicles. To address the computational challenge, we propose a data-driven decomposition algorithm to support a multivehicle multivisit rebalancing strategy by decomposing the multivehicle routing problem into smaller and tractable single-vehicle routing problems, which can be solved in parallel. Finally, extensive numerical experiments using real-world data from New York City Citi Bike demonstrate the accuracy of the proposed bike demand predictors, the impact of demand substitution, and the efficiency of the data-driven optimization framework. History: Accepted by Ram Ramesh, Area Editor for Data Science & Machine Learning. Funding: This work was supported by the National Natural Science Foundation of China [Grant 72201222] and the Hong Kong Research Grants Council [Grants CityU 21500220 and CityU 11504322]. Supplemental Material: The software that supports the findings of this study is available within the paper and its Supplemental Information ( https://pubsonline.informs.org/doi/suppl/10.1287/ijoc.2022.0182 ) as well as from the IJOC GitHub software repository ( https://github.com/INFORMSJoC/2022.0182 ). The complete IJOC Software and Data Repository is available at https://informsjoc.github.io/ .

The two-stage pricing of preannouncement for platform introducing self-operated logistics under consideration of the first- or second-mover advantage

PurposeThe optimization of transport efficiency by self-operated logistics has brought competitive advantages to platform, who is gradually developing self-operated logistics and adopting the preannouncement to announce the related information in advance. The purpose of this paper is to explore the development order of self-operated logistics on platform under consideration of preannounce behavior.Design/methodology/approachThis paper considers the sequence of platform constructing the self-operated logistics and constructs the two-stage pricing models to analyze the optimal pricing of platforms under different preannounce strategies, including four scenarios: {no-preannounce, first mover}, {no-preannounce, second mover}, {preannounce, first mover} and {preannounce, second mover}.FindingsThe authors receive several conclusions: First, under no-preannounce scenario, regardless of the sequence of entry into self-operated logistics market, when the quality differentiation of two platforms’ self-operated logistics is moderate, the ratio pricing of two platforms at competition stage is positively correlated with quality differentiation of their self-operated logistics. Additionally, there exists the substitution effect between preannouncement and quality differentiation under no-preannounce condition, and the first-mover platform should increase the pricing of the monopoly phase until it is twice as high as its pricing during the competition phase. Interestingly, the pricing of platform and the strategy for developing self-operated logistics are symmetric between first- and second-mover scenarios.Originality/valueFirst, this study analyzes the pricing and self-operated logistics construction under different preannounce strategies, enriching the interdisciplinary research on corporate marketing and providing scientific suggestions on how to use preannouncement to acquire competitive advantages. Second, this paper also considers the sequence of platform developing self-operated logistics and analyzes how platform develops self-operated logistics as well as pricing to gain first-mover and second-mover advantages. Third, this paper develops the two-stage pricing models that consider the continuity of pricing in different cycles, enriching the relevant theories and models.

Effects of task-shifting from primary care physicians to nurses: an overview of systematic reviews.

Task-shifting from primary care physicians (PCPs) to nurses is a means of overcoming PCP shortages and meeting the needs of patients receiving primary care. The aim of this overview of systematic reviews is to assess the effects of delegation or substitution of PCPs' activities by nurses on patient relevant, clinical, professional and health services-related outcomes. We conducted a systematic literature search for secondary literature in Medline, Embase, Pubmed, the Cochrane Library, and the Cumulative Index of Nursing and Allied Health Literature (CINAHL). We included systematic reviews and meta-analyses that analysed randomised controlled trials (RCTs) and controlled, prospective trials in English and German. Abstracts and full-text articles were screened independently by two reviewers. Full-text articles were assessed using the Overview Quality Assessment Questionnaire. After data extraction a narrative synthesis was performed. We defined patient-relevant outcomes as our primary outcomes. We included six systematic reviews. The interventions included first contact, history taking and assessment, patient education, review of drug treatment, referrals to GPs and other health professionals, ordering further investigations and ongoing care. Two meta-analyses showed a relative risk reduction of mortality in favour of nurse-led care, whereby the reduction in one analysis was significant. The effect was highest in the group of more highly qualified nurse practitioners (RR 0.19), as opposed to nurse practitioners (RR 0.76) and registered nurses (RR 0.92). Two meta-analyses showed a relative risk reduction in hospital admissions and patient satisfaction. Whereas care conducted by physicians and registered nurses led to the same outcomes, care conducted by nurse practitioners led to better outcomes (RR 0.74). An analysis according to nursing group showed that patients were more satisfied with treatment by registered nurses (SMD 1.37) than with treatment conducted by nurse practitioners and more qualified nurse practitioners (SMD 0.17). In terms of patient-relevant outcomes, no differences were observed between physician-led care and nurse-led care in terms of physical function, quality of life and pain. Nurse-led care is probably as safe or safer than physician-led care in terms of mortality and hospital admissions. However, the impact of nursing staff training has not been sufficiently examined.

High-Pressure Behaviors of Hydrogen Bonds in Fluorine-Doped Brucite.

Brucite, Mg(OH)2 (P3̅m1, Z = 1), is a prototype material for studying hydrogen bonds in solid hydroxides. In this study, substitutional effects of fluorine (F) on the hydrogen-bonding geometries of hydrogenated and deuterated brucite were investigated under ambient conditions and at high pressure using combined experimental methods of neutron powder diffraction, Raman spectroscopy, and infrared (IR) spectroscopy. Under ambient conditions, neutron powder diffraction results showed that F substitution decreased the donor-acceptor distance and increased the hydroxyl covalent bond lengths of both hydrogenated and deuterated brucite, strengthening the hydrogen bond. Red shifts of the hydroxyl stretching modes also indicated an elongation of d(O-H) and d(O-D). High-pressure neutron diffraction experiments were performed on Mg(OH)1.81F0.19 and Mg(OD)1.74F0.26 up to 7.04 and 10.02 GPa, respectively. For both samples, changes in the hydrogen-bonding geometries did not indicate hydrogen-bond strengthening under high pressure. Compared with Mg(OD)2, the doping of F suppressed the increase of the hydroxyl covalent bond length, the hydrogen-bond angle, and the cone angle, inhibiting pressure-induced hydrogen-bond strengthening. High-pressure Raman and IR absorption spectroscopic measurements on Mg(OD)2 and Mg(OD)1.79F0.21 up to 9.7 and 13.7 GPa confirmed that F substitution restrains pressure-induced hydroxyl elongation.

Short-term organic fertilizer substitution increases sorghum yield by improving soil physicochemical characteristics and regulating microbial community structure

IntroductionChemical fertilizer reduction combined with organic fertilizer (organic fertilizer substitution) has a positive impact on crop productivity and sustainable development. However, the effects of short-term organic fertilizer substitution on microbial community structure and functions of sorghum rhizosphere soil and on sorghum yield remain unclear. Herein, this study investigated the short-term effects of organic fertilizer substitution on sorghum soil physicochemical properties, microbial community structure and enzyme activities using Metagenomic sequencing technology.MethodsThe fertilization treatment included no fertilization (CK), pure chemical fertilizer N (CF), substitution of 25% chemical fertilizer N with organic N (NF25), substitution of 50% chemical fertilizer N with organic N (NF50), substitution of 75% chemical fertilizer N with organic N (NF75), and pure organic fertilizer N (NF100); soil samples were collected and analyzed in the flowering period of sorghum.Results and DiscussionThe results showed that the suitable organic fertilizer substitution rate of sorghum field was 50%, and its yield was the highest among all treatments (9789.9 kg/hm2). Compared with the CF treatment, a medium ratio (50%) of organic fertilizer substitution significantly reduced soil alkalization (by 3.05%), improved soil nutrients, enhanced soil enzyme activities, and increased sorghum yield (P < 0.05). After organic fertilizer substitution treatment, higher protein, fat, and total starch levels accumulated in sorghum grains, and the tannin content of grains decreased. The effect of organic fertilizer substitution on bacterial diversity was greater than that on fungal diversity. Among the dominant bacterial phyla, the medium ratio of organic substitution treatment significantly increased the relative abundances of Proteobacteria (by 3.57%) and Actinomycetes (by 14.94%), and decreased the relative abundances of Acidobacteria (by 5.18%) and Planctomycetes (by 7.76%) compared with no fertilization, while the dominant fungal phyla did not respond significantly to the addition of organic fertilizer. Organic fertilizer substitution also improved soil microbial metabolic pathways, biosynthesis of secondary metabolites, and carbon metabolism. The biomarkers enriched in inorganic fertilizer treatment and organic fertilizer substitution treatments had similar relevant environmental elements but reversed correlation trends. Moreover, soil Alkali-hydrolyzable nitrogen and L-leucine aminopeptidase were important environmental factors influencing the structure of bacterial and fungal communities in sorghum soils, respectively. Soil nutrient levels and microbial communities together explained the variation in annual sorghum yield. The results of this study provide evidence that short-term organic fertilizer substitution increases sorghum yield by improving soil properties and regulating microbial community structure.

Impact of chlorine substitution on valence orbitals and ionization dynamics in 3-chloropyridine: Insights from high-resolution vacuum ultraviolet mass-analyzed threshold ionization study.

In this study, the effects of chlorine substitution on the valence orbitals and electronic states of 3-chloropyridine (3-CP) were investigated utilizing high-resolution vacuum ultraviolet mass-analyzed threshold ionization (VUV-MATI) spectroscopy and computational methods. High-quality vibrational spectra were obtained from the VUV-MATI spectra of 3-CP isotopomers (35Cl and 37Cl), revealing high-quality vibrational spectra for the lowest cationic states. The adiabatic ionization energies (AIEs) of these isotopomers were accurately determined, providing detailed information about the electronic structure and ionization dynamics. Intense spectra peaks were linked with the D1 excited state of the 3-CP cation, with vibronic transitions in this state closely matching those predicted by Franck-Condon simulations. This provided insights into the cationic structure and the roles of the highest occupied molecular orbital (HOMO) and the HOMO-1. The HOMO was primarily a π orbital of the pyridine ring, while the HOMO-1 consisted of nonbonding orbitals. The AIEs suggested that meta-chlorine substitution stabilizes nonbonding orbitals less effectively than ortho substitution, indicating closely spaced electronic states in the 3-CP cation. Minor discrepancies in vibrational frequencies and intensities, particularly above 800cm-1, suggested the presence of vibronic coupling, warranting further investigation. Overall, this study provided a comprehensive understanding of the vibronic and ionization properties of 3-CP, emphasizing the influence of the position of the chlorine substitution on molecular orbitals and the value of advanced theoretical and experimental approaches for analyzing the vibrational spectra of complex molecules.

Metal-Metal Bonding in Tri-Actinide Clusters: A DFT Study of [An3Cl6] z (z = 1-6) and [An3Cl6Cp3] z (z = -2- +3; An = Ac, Th, Pa, U, Np, Pu).

The actinide-actinide bonding in tri-actinide clusters [An₃Cl₆]ᶻ (An = Ac-Pu, z = 1-6) and [An₃Cl₆Cp₃]ᶻ (z =-2-+3; Cp = (η5-C5H5)) is studied using density functional theory. We find 3-centre bonding similar to the tri-thorium cluster [{Th(η⁸-C₈H₈)(μ₃-Cl)₂}₃{K(THF)₂}₂]∞, as we previously reported (Nature 2021, 598, 72-75). The population of 3-centre molecular orbitals (3c-MOs) by zero, one or two electrons correlates with shortening of the An-An bond lengths, which also decrease with increasing actinide atomic number, consistent with the contraction of the actinide valence atomic orbitals. Mulliken analyses indicate that these 3c-MOs predominantly involve An 6d and 5f orbitals. Various methods evidence the presence of An-An bonding in most systems with populated 3c-MOs, including bond orders (Mayer and Wiberg), quantum theory of atoms in molecules metrics (ρ, ∇²ρ, -G/V, H, delocalization indices), electron localization function, and electron density assessments. Additionally, we explore the effect of Cp ligand substitution on uranium complexes, finding that bulkier Cp ligands can induce U-U bond distortions and result in slightly longer U-U bonds. Overall, this study advances our understanding of metal-metal bonding in tri-actinide clusters, highlighting its effects on geometric and electronic structures.

Long-Term Impact of the Bloor Viaduct Suicide Barrier on Suicides in Toronto: A Time-Series Analysis: Effet à long terme de la barrière anti-suicide du viaduc Bloor sur les suicides à Toronto : une analyse chronologique.

A suicide prevention barrier was installed at Toronto's Bloor Viaduct bridge in 2003. It was associated with short-term location substitution, possibly mediated by media effects that did not persist over 1 decade. The long-term impact of the barrier is unknown. We examined rates of suicides by jumping from the Bloor Viaduct, other bridges and by other methods using coroner's records in Toronto (1998-2020). We used interrupted time-series Poisson regression analyses to model changes in quarterly bridge-related suicides after barrier installation. A secondary analysis explored the potential substitution effects of suicide by other methods. Of 5219 suicides from 1998 to 2020, 303 were by jumping from bridges. After controlling for covariates, installation of the Bloor Viaduct suicide barrier was associated with a 49% step decrease in bridge-related suicide in the next quarter in Toronto (incidence rate ratio [IRR] = 0.51, 95% CI, 0.30 to 0.86) with no rebound increase in bridge-related suicide during the subsequent 17 years after the original drop (IRR = 0.99, 95% CI, 0.96 to 1.03). There was also no associated change in suicides by other methods after the barrier (IRR = 1.04, 95% CI, 0.90 to 1.20). Contrary to initial findings, these results indicate an enduring suicide prevention effect of the Bloor Viaduct suicide barrier. They support the long-term utility of structural interventions at high-frequency sites for suicide.

Insights into C-H Activation Reactivity of Fe (IV)O Porphyrinoid Complexes: A Computational Investigation.

This work presents a detailed comparative analysis of C-H activations catalyzed by three different Fe(IV)O porphyrinoid complexes. The study considers the usual heme porphyrin (complex I) as the base compound, porphyrazine (complex II), which is obtained by replacing carbon with nitrogen at the meso position, and phthalocyanine (complex III), which is obtained through the peripheral benzoannulation of porphyrazine. The focus here is to explore the impact of bridging groups and peripheral functionalization in heme systems on reactivity. Factors such as distortion energy and electron acceptor orbitals significantly affect the overall reactivity. The effect of substitution on quantum mechanical tunneling, using H/D kinetic isotope effect studies, is also included. The results reveal a fascinating reactivity order: meso nitrogen substitution enhances reactivity, while additional benzo-annulation hinders reactivity, leading to the order complex II > complex I > complex III. In comparison to the usual Cpd I, which is Fe(IV)O-porphyrin π cation radical with an -SH axial ligand, complex II was found to be more reactive. The electron affinity of the Fe(IV)O complexes and the dissociation energy of the forming Fe(IV)O-H bond aligns with observed reactivity trend. These findings support the use of accessible iron frameworks derived from porphyrin in C-H activation processes.

Substitution effect and charge transport properties in organic field-effect transistors (OFETs) of simply functionalized carbazole derivatives

Development of low cost, easy-preparation and good performance organic semiconductors is in high demand for the practical application of organic field-effect transistors (OFETs). Even though the π-extended carbazole derivatives have been intensively studied in OFETs, the application potential of simple carbazole derivatives, i.e., owning simple substituents directly at carbazole backbone, remains unclear. In this work, we designed and synthesized a series of carbazole derivatives with simple phenyl or thienyl functionalization directly at 2,7- or 2,6-positions, respectively. The photophysical and electrochemical properties, together with their theoretical frontier molecular orbitals and energy levels were investigated. The molecular conformations and packing structures in the solid state of these molecules were understood by single-crystal structure analysis. In addition, single-crystal based OFETs were fabricated to explore their intrinsic charge transporting properties, in which the 2,7-diphenyl modified carbazole derivative showed hole-transporting mobilities up to 0.16 cm2 V-1 s-1. Our study not only proves that simply functionalized carbazoles have great potentials to act as easy-preparation high-performance p-type semiconducting materials, but also illustrates that 2,7-positon functionalization is more advantageous for balancing the molecular conformations and packing structures of carbazole derivatives to achieve good charge transport performance.

Effects of Lu-doping on the magnetic behaviour and ordering of (Ho[formula omitted]Lu[formula omitted])2Fe2Si2C

We have investigated the effects of Lu substitution on the magnetic behaviour and ordering of (Ho1−xLux)2Fe2Si2C (x = 0.32 and 0.46) by high-resolution neutron powder diffraction, magnetisation and specific heat over the temperature range 2 to 300 K. Our study has establised that the antiferromagnetic (AFM) state is weakened upon Lu substitution and that the Néel temperature TN shifts towards lower temperature with increasing Lu content. The replacement of the magnetic Ho3+ ion by the non-magnetic Lu3+ ion of smaller atomic radius, leads to a modification of the crystal field levels, as indicated by the specific heat measurements. Neutron diffraction data analysis reveals that the magnetic structure of undoped Ho2Fe2Si2C, which exhibits a commensurate, antiferromagnetic ordering of the Ho sublattice along the b-axis with a propagation vector k = [0, 0, 12], is maintained in the Lu-doped (Ho1−xLux)2Fe2Si2C compounds.

Synergistic effects of liquid phase sintering and B-site substitution to enhance proton conductivity of BaZr0.1Ce0.7Y0.1Yb0.1O3-δ for protonic ceramic fuel cell

This paper is dedicated to improving the sintering and conductivity of BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb) by adding ZnO-CuO dual-sintering aids. The synergistic effects of liquid-sintering of Zn and B-site substitution of Cu on the sinterability and proton conductivity of BZCYYb are systematically investigated. X-ray diffraction (XRD) analysis of BZCYYb after addition of ZnO-CuO (BZCYYb-Zn-Cu) confirms the complete perovskite phase formation without any secondary phase. The substitution of Ce4+ (0.87 Å) with Zn2+ (0.74 Å) or Cu2+ (0.73 Å) induces a shift in XRD diffraction peak to higher angle due to a decrease in lattice constant. Energy dispersive X-ray spectroscopy analysis indicate a distinct distribution of Zn primarily at the grain boundaries, while Cu is predominantly located within the grains of BZCYYb-Zn-Cu. The addition of ZnO-CuO into BZCYYb results in a denser microstructure with larger average grain size. Furthermore, the substitution of Ce4+ by Cu2+ increases the concentration of oxygen vacancies and reduces activation energy. For BZCYYb-Zn-Cu, the proton conductivity reaches 4.52×10-2 S/cm at 750 °C, approximately 3 times higher than that of BZCYYb. This enhancement can be attributed to the synergistic effects of larger average grain size resulting from liquid phase sintering of Zn, low active energy, and high concentration of oxygen vacancies arising from Cu B-site substitution. BZCYYb-Zn-Cu is used as the electrolyte for anode support SOFC, and the single cell exhibits remarkable electrochemical performance and excellent stability in H2 fuel. This research establishes a crucial theoretical foundation for the preparation and performance evaluation for large-size protonic ceramic cell.

Effect of Cr substitution in ZnFe2O4 nanoparticles on the electron transfer at electrochemical interfaces

In this study, we explored the effect of Cr³⁺ substitution by partially and fully replacing Fe³⁺ in the normal spinel ZnFe₂O₄ crystal structure at electrochemical interfaces. The resulting ZnCrₓFe₂₋ₓO₄ nanomaterials exhibited an average particle size between 20 and 50 nm with a spherical morphology. The materials also demonstrated energy band gaps ranging from 2.1 to 3.1 eV. X-ray diffraction (XRD) analysis confirmed that all the synthesized materials maintained a normal spinel structure, attributed to the octahedral site preference energy (OSPE) of Zn²⁺, Fe³⁺, and Cr³⁺ ions. Electrochemical performance assessments revealed that the ZnFe₂O₄-based sensor achieved a sensitivity of (37.8 ± 0.2) μA/mM with a kinetic rate constant of (13.1 ± 2.8) ms⁻¹, while the ZnCr₂O₄-based sensor exhibited a sensitivity of (32.4 ± 0.5) μA/mM and a kinetic rate constant of (3.73 ± 0.55) ms⁻¹ in the detection of paracetamol, whereas ZnCrFeO4 sensor has produced the second-best sensitivity (35.7 ± 0.1 μA/mM) and the rate constant (4.53 ± 0.54 ms⁻¹) with the lowest limit of detection (1.94 ± 0.01 μM). These differences in electrochemical performance were correlated with the variations in the energy band gaps caused by the restructuring of the normal spinel structure. Our findings indicate that the ZnFe₂O₄ sensor has a higher potential for direct electron transfer, whereas the other sensors are more likely to facilitate surface-mediated electron transfer.

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.

Substitution or complementary effects: The impact of neighborhood effects and policy interventions on farmers’ pesticide packaging waste recycling behavior

Substitution or complementary effects: The impact of neighborhood effects and policy interventions on farmers’ pesticide packaging waste recycling behavior

Technology shock of ChatGPT, social attention and firm value: Evidence from China

The release of ChatGPT has attracted widespread attention and triggered fluctuations in the capital market. This study employs difference-in-differences (DID) and event study (ES) to investigate the effects of ChatGPT's release on the cumulative abnormal return (CAR) of listed companies in China. The results reveal that a series of ChatGPT launch events, including GPT-3.5 and GPT-4, have a significantly positive impact on the firm value of the companies focused on ChatGPT, with dynamic effects. In the initial two months after the release of ChatGPT, the Chinese stock market exhibited an undervaluation of GPT-focused companies, indicating information asymmetry and competitive substitution effect. With the widespread promotion of generative AI, social recognition of ChatGPT's potential value increased. This study verifies the moderation effect of social attention in strengthening ChatGPT's impact, demonstrating that a higher search index for ChatGPT enhances stock returns for GPT-focused companies. Heterogeneity tests reveal that the impact of ChatGPT is significantly positive for large or non-state-owned companies, while small or state-owned companies show no significant effect. From the perspective of labor structure, companies dominated by technical and production personnel experience positive effects, whereas those dominated by sales personnel do not. In the eastern regions with more favorable digital economic innovation environments, companies experience a notably positive impact. This paper provides a theoretical explanation and empirical evidence for the microeconomic impact of generative AI in the Chinese context, offering valuable insights for both government and firms.