Search Results (546)

The repellent activities (Periplaneta americana) of lone and binary mixtures of terpenoids—geranial, trans-anethole, and trans-cinnamaldehyde—against adult American cockroaches were evaluated in this study. The respective efficacies of these mixtures were compared with that of 12% (w/w) DEET. Safety bioassays for all formulations on non-target species, namely, earthworms (Eudrilus eugeniae) and guppy fish (Poecilia reticulata), were conducted to identify natural compounds with repellent efficacy equal to or surpassing that of DEET while ensuring ecological safety for non-target organisms such as fish and earthworms. All mixtures (RC₅₀ of 0.3 to 1.6 µL/cm³) were more effective than all lone terpenoids (RC₅₀ of 6.2 to 9.1 µL/cm³) and DEET (RC₅₀ of 3.0 µL/cm³), demonstrating strong synergy, with an increased repellent value (IV) of 79 to 96%. The strongest repellency, 98.0% at 72 h and an RC₅₀ of 0.3 µL/cm³, was achieved using geranial + trans-cinnamaldehyde (1:1). This mixture was 5.9 to 10 times more effective as a repellent than DEET. The toxicity of every lone terpenoid and terpenoid mixture to non-target species was low; hence, these mixtures can be considered safe, whereas DEET was highly toxic to non-target species (100% mortality). The terpenoid mixture geranial + trans-cinnamaldehyde showed strong repellency against P. americana. Full article

In the context of carbon neutrality, the large-scale integration of renewable energy sources has led to frequent load changes in coal-fired boilers. These fluctuations cause key operational parameters to deviate significantly from their design values, undermining combustion stability and reducing operational efficiency. To address this issue, we introduce a novel predictive control method to enhance the control precision of key parameters under complex variable-load conditions, which integrates a coupled predictive model and real-time optimization. The predictive model is based on a coupled Transformer-gated recurrent unit (GRU) architecture, which demonstrates strong adaptability to load fluctuations and achieves high prediction accuracy, with a mean absolute error of 0.095% and a coefficient of determination of 0.966 for oxygen content (OC); 0.0163 kPa and 0.987 for bed pressure (BP); and 0.300 °C and 0.927 for main steam temperature (MST). These results represent substantial improvements over lone implementations of GRU, LSTM, and Transformer models. Based on these multi-step predictions, a WOA-based real-time optimization strategy determines coordinated adjustments of secondary fan frequency, slag discharger frequency, and desuperheating water valves before deviations occur. Field validation on a 300 t/h boiler over a representative 24 h load cycle shows that the method reduces fluctuations in OC, BP, and MST by 62.07%, 50.95%, and 40.43%, respectively, relative to the original control method. By suppressing parameter variability and maintaining key parameters near operational targets, the method enhances boiler thermal efficiency and steam quality. Based on the performance gain measured during the typical operating day, the corresponding annual gain is estimated at ~1.77%, with an associated CO₂ reduction exceeding 6846 t. Full article

Background: An increasing number of university students report feeling lonely, a negative experience arising from a mismatch between perceived and actual social relationships. Loneliness has been linked to poorer mental health. However, the relationship between qualitative (sources of loneliness) and quantitative (high or low) differences in loneliness and mental health is under researched. The aims of this research were to (a) identify profiles of loneliness among university students across three indicators of loneliness, namely, social, family, and romantic indicators, using latent profile analysis (LPA); (b) examine the differences among identified profiles based on dimensions of mental health indicators (depression, anxiety, and stress), social support, and life satisfaction; and (c) assess profile membership based on demographic variables (gender, social isolation, relationship status, and education characteristics) and the Big Five personality traits (extraversion, agreeableness, openness, conscientiousness, and neuroticism). Method: A cross-sectional survey was conducted on 912 university students from five cities in Uttar Pradesh, India. Participants completed questionnaires covering demographic details and validated measures assessing loneliness, depression, stress, anxiety, social support, life satisfaction, and the Big Five personality traits. Data were analyzed using the latent profile module in Jamovi and fit indices, namely, BIC, AIC, and BLRT, and entropy was used to select the best profile. Results: The latent profile analysis identified four profiles for university student loneliness, including Social and emotional lonely (31.4%), Moderate romantic lonely (23.8%), Moderate social lonely (8.2%), and Severe romantic lonely (36.6%). Moreover, the Social and emotional lonely profile scored the highest on depression, anxiety, and stress. The Moderate romantic lonely profile scored the highest on life satisfaction and social support. Being in a relationship decreased the likelihood of being categorized as Severe romantic lonely. In terms of personality, neuroticism was the strongest predictor of profile membership. This study is a step towards identifying at-risk lonely individuals with varying sources of loneliness. Identifying different profiles of lonely individuals will have direct implications for designing interventions that cater to a particular group rather than a one-size-fits-all approach. Full article

Ensuring the stability of underground structure engineering in deep coal mines is the key to the successful exploitation of deep geothermal resources in coal mines. Therefore, this paper carried out mechanical tests on rock–coal combinations under different rock properties and studied their stress–strain laws, energy and acoustic emission evolution laws, as well as deformation and failure laws. The main conclusions are as follows: (1) The strength of rock–coal assemblages mainly depends on the strength of coal samples far from the interface, and coal samples are the main bearing bodies in the process of uniaxial compression. (2) Because oil shale has a relatively low strength and large deformations, the rock property of relatively large deformations can improve the ability of the combinations to convert external energy into elastic energy. (3) The acoustic emission energy rate signals of rock–coal combinations can be divided into three stages: quiet, active, and sudden increase. The acoustic emission energy rate signals of limestone–coal and sandstone–coal assemblages are of the “lone-shock” type, while the acoustic emission energy rate signals of oil shale coal assemblages are of the “Multi-peak” type. (4) When oil shale with a relatively low strength and large deformations occurs, both the rock sample and coal sample of the combination appear to have deformation localization zones, and the deformation localization zones in the rock sample and coal sample run through the rock–coal interface, which eventually leads to the failure of both the rock sample and coal sample of the combination. These relevant research results help ensure the safe utilization of geothermal resources in deep coal mines and promote the global energy structure in accelerating the transformation to low-carbon and clean energy. Full article

This study investigated the efficiency of biochar in eliminating Cd(II) and Pb(II) ions from slurries generated from construction-derived waste materials. The construction waste slurry samples consisted of genuinely contaminated sludge sediments. To improve the adsorption capacity of biochar for metal ions, coconut shell-derived biochar was subjected to hydrochloric acid treatment. The modified biochar demonstrated an improved porous structure and showed a higher concentration of oxygen-containing functional groups compared to the untreated biochar. After a 48 h contact with the contaminated slurry, the treated biochar attained removal efficiencies of 21.15% for Cd(II) and 19.43% for Pb(II). The kinetic study of the adsorption process conformed to a pseudo-second-order model. Density functional theory (DFT) computations clarified the adsorption mechanism of Cd(II) and Pb(II) by carboxyl (-COOH) and hydroxyl (-OH) functional groups. The findings demonstrated that functional groups contribute lone-pair electrons for the adsorption of heavy metal ions. The carboxyl (-COOH) functional group exhibited a greater affinity for binding Cd(II) and Pb(II) ions than the hydroxyl (-OH) group, which explains the improved adsorption efficiency seen in biochar treated with hydrochloric acid. These findings offer theoretical validation for the use of hydrochloric acid-modified biochar as an efficient adsorbent for the remediation of sludge contaminated with Cd(II) and Pb(II). Full article

The photochemical behavior of substituted pyridine N-Oxides is characterized by complex rearrangements culminating in the formation of valuable photoproducts. The CAS(10,8)/cc-pVDZ approach with NEVPT2 corrections is applied to investigate geometric distortions associated with the $S_1$ excited state, conical intersections, and the ultimate transformation of pyridine N-Oxides into oxaziridine-like derivative formations. Our results reveal that the deactivation of the $S_1$ excited state is driven by an out-of-plane rotation of the N-O oxygen atom, resulting in the formation of a lone pair over the nitrogen atom. Along this excited-state reaction pathway, the N-O bond undergoes significant weakening, while a C=C double bond emerges mainly in the excited state. The deactivation at the minimum-energy conical intersection leading to the ground state reveals the formation of an oxaziridine-like intermediate, which subsequently converts into a 1,2-oxazepine derivative. Full article

In this study, we systematically investigated the piezoelectric and carrier transport properties of two-dimensional (2D) Bi-based chalcohalide monolayers (BiXY, X = Se, Te; Y = Br, I) using first-principles calculations. The phonon dispersion and elastic properties proved that BiXY monolayers are dynamically and mechanically stable. Our results reveal that the stereochemically active 6s² lone-pair electrons of Bi³⁺ play a crucial role in determining the structural and electronic characteristics of these systems. The simultaneous enhancement of Born effective charges and the strong sensitivity of atomic positions to external strain give rise to pronounced piezoelectric responses in BiXY monolayers. Specifically, the calculated piezoelectric coefficients (d₁₁) reached 13.16 and 17.76 pm/V for BiSeBr and BiSeI, respectively. The carrier transport properties were estimated using the deformation potential (DP) theory, which yielded upper-bound values under idealized conditions. For instance, in BiTeBr, the effective masses of electrons and holes were 0.15 and 0.40 m₀, respectively, leading to high carrier mobilities of 2736.1 and 2689.9 cm² V⁻¹ s⁻¹. These findings highlight the potential of Bi-based chalcohalide monolayers as promising candidates for next-generation multi-functional nanoelectronic and piezoelectric devices. Full article

Background/Objectives: Cardiac amyloidosis (CA) as well as coronary artery disease (CAD) are both highly prevalent among the elderly. However, both the prevalence and risk factors associated with significant CAD among patients with CA, as well as potential outcome disparities, remain mainly unexplored. This study aimed to show the prevalence of CAD in patients with CA, as well as to assess outcomes and differences in late gadolinium enhancement (LGE) in comparison to patients with lone CA. Methods: We retrospectively assessed CA patients who underwent CAD assessment between 2013 and 2023. The primary endpoint was all-cause death. A subgroup underwent cardiac magnetic resonance imaging (CMR) with LGE assessment. Results: Of 255 consecutive patients with CA, 81 patients had significant CAD. Differences could be found with respect to age, sex, arterial hypertension, and hyperlipidemia. Significant differences in CMR features could only be found with respect to indexed left-ventricular end-diastolic volume, as well as left-ventricular mass. CAD-specific LGE was present only in 17.7% of patients with CAD, while most patients showed typical amyloid LGE, making a viability diagnosis difficult via CMR, especially in patients with end-stage CA. No differences in outcomes could be observed according to the prevalence of CAD. Conclusions: Concomitant obstructive CAD is highly prevalent among patients with CA. However, the presence of CAD does not influence patient outcomes. Furthermore, our data suggests that CAD viability testing by CMR might be complicated in patients with concomitant CA due to the high prevalence of amyloid-specific LGE. Full article

Background and Clinical Significance: Atrial fibrillation is a rare disorder in the pediatric population in the absence of underlying heart disease. A specific arrhythmia, known as lone pediatric atrial fibrillation, can occur without identifiable structural heart abnormalities. Case Presentation: We report a case of a 12-year-old obese child with symptomatic hypertension and atrial fibrillation diagnosed through an electrocardiogram (ECG). Conclusions: The patient was rapidly managed with intravenous metoprolol, and he subsequently started cardiologic treatment and clinical follow-up. This case underlines the possibility of performing routine ECGs in the follow-up of obese children. Full article

How individuals and organizations interface with the digital economy has been largely influenced by transformations ushered in on the global financial map by the rapidly expanding Financial Technology (FinTech). This paper seeks to shed light on the successes of FinTech, namely on how it contributed to sustainability through financial inclusion, reduction in reliance on cash and the promotion of an innovation-driven economy known for being paperless. Based on contributions from students at Taif University in Saudi Arabia, determinants of FinTech adoption intentions are analyzed using data from n = 544. Our study focuses on evaluating the effects of financial, technical and external factors on adoption behavior by using a two-prong approach: first, we use the DeLone and McLean IS Success Model; then we employ a Second-Order Construct using Structural Equation Modelling (SEM). The results indicated that the strongest effects on attitudes stem from technical factors—information, system and service quality. Additionally, they also show that adoption intention is considerably shaped by financial as well as external dimensions. The Saudi Vision 2030 has set national goals of digital transformation, financial inclusion and human capital empowerment. This study provides a modest contribution to those goals by fostering FinTech adoption among the youth. Furthermore, its findings also offer educators, policymakers and Fintech providers a platform to enhance literacy, strengthen trust and develop sustainable digital finance ecosystems in line with the Kingdom’s Vision 2030 objectives. Full article

The emergence of generative AI, particularly the widespread accessibility of ChatGPT, has led to challenges for higher education. The extent and manner of use are under debate. Local empirical investigations about the use and acceptance of ChatGPT contribute to effective policymaking. The study employs a specialized approach, utilizing an information system view based on the DeLone and McLean Information Systems Success Model as its theoretical framework. A survey was conducted to assess students’ opinions about ChatGPT regarding its usefulness in their studies. The model was tested using PLS-SEM with 466 Hungarian and Romanian higher education students. The model examined six constructs as information quality, system quality, service quality, use, user satisfaction, and net benefits. The results confirmed the effects of information quality and system quality on use and satisfaction, whereas service quality did not make a significant contribution. Satisfaction was found to be the key driver to use. The study contributes to a deeper understanding of AI acceptance in higher education and provides valuable considerations for policymaking. A data-oriented, task-focused policymaking is recommended over system-based regulation. Additionally, a comprehensive framework model is required for international comparisons, which combines information systems success and technology acceptance models. Full article

This study assesses De Lone and McLean’s Information System (D&M IS) Success Model concerning DAS throughout small and medium enterprises (SMEs) in Saudi Arabia (SA). The present work mainly sought to evaluate the impact of information quality (IQ), system quality (SysQ), service quality (SrvQ) serving, system utilization, and user satisfaction (Usat) on the usage of the Digital Accounting System (DAS), which is posited to ultimately improve the quality of sustainable decision-making. The research utilized a quantitative methodology, employing a self-administered questionnaire to collect data from 328 decision-makers who are knowledgeable about actual DAS usage by SMEs in SA. Subsequent to gathering data, validation was conducted via Structural Equation Modeling (SEM) by utilizing smart-PLS software. The findings indicate that SysQ and IQ significantly influenced system utilization, although SrvQ did not. DAS was determined to significantly influence user happiness. Moreover, system utilization and user satisfaction positively influenced DAS, thereby affecting the sustainability of decision-making and reflecting the overall benefits of DAS. This work enhances the current IS literature by identifying the characteristics that affect the net advantages of DAS, with the suggested model evaluated in SMEs in SA utilizing DAS. This study serves as a reference to elucidate the significance of DAS and offers consequences, limitations, and prospects for further research. Full article

Azomethine ylides (AMYs) have a nitrogen–carbon double bond and an electron lone pair on the nitrogen atom. They are essential 1,3-dipoles for [3+2] cycloadditions in the synthesis of pyrrolidine-containing heterocycles. Significant progress in 1,3-diplolar cycloadditions has been made in the construction of novel heterocyclic scaffolds, with efforts to broaden substrate scope, enhance stereoselectivity, and integrate green chemistry principles. This article summarizes double cycloadditions of AMYs derived from amino esters and amino acids for the synthesis of novel polyheterocycles. The design of double cycloadditions through the pot, atom, and step economic (PASE) method to increase the reaction efficiency is discussed. The examples presented in this paper may be applied to the synthesis of biologically active molecules. Full article

The analysis of time-resolved S₁–S_n absorption spectra in the 0–500 ps range, together with quantum-chemical calculations, uncovered a photorecoordination reaction for the following complexes of CD6 (a bis(aza-18-crown-6)-containing dienone (ketocyanine dye) with a central cyclohexanone fragment): CD6·(Mⁿ⁺)₂ (M = Ba²⁺, Sr²⁺, Ca²⁺, K⁺). This process takes place over hundreds of fs and involves an “axial-to-equatorial” conformational change, with the solvation shell undergoing rearrangement as well. The characteristic photorecoordination times were found to correlate with the stability constants of the complexes. The lifetimes for the fluorescent states of CD6 and its complexes, namely CD6·(Mⁿ⁺)₂ (M = Ba²⁺, Sr²⁺, Ca²⁺, K⁺), are different; ergo, there is no photoejection of crowned cations into the solution. The calculated conformational profiles in the ground and excited states indicate the presence of an energy barrier in this process. A general photorelaxation pathway is suggested for CD6·(Mⁿ⁺)₂ metal complexes (M = Ba²⁺, Sr²⁺, Ca²⁺, K⁺). The coordination of cations via the carbonyl moiety in the dye molecule promotes photorecoordination of metal cations in the cavities of the azacrown ether fragment. Photorecoordination times were found to correlate with the degree of conjugation between the lone pairs in the N atoms of the aza-18-crown-6 ether and the π subsystem in the dye molecules (established for the CD4–CD6 metal–dye complex series, where CD4 and CD5 are related dyes with central cyclobutanone and cyclopentanone fragments, respectively). Full article

This paper comprehensively reports experimental proof of parity violation in the ground and photoexcited states of three mirror-symmetric Si–Si bond polymers in homogeneous solutions of achiral molecules under non-stirring conditions by analyzing 370 chiroptical datasets relating to multiple second-order helix–helix transitions in the circular dichroism (CD) of poly(di-i-butylsilane) (iBS), poly(di-i-pentylsilane) (iPS), and poly(di-i-hexylsilane) (iHS) in achiral alkanols and p-dioxane-h₈/-d₈. Particularly large (–)-CD of g_abs = −3.1 × 10⁻² at 290 nm was found for iBS in i-pentanol at 25 °C. Notably, iPS in n-propanol at −5 °C generated (–)-CD with g_abs = −0.48 × 10⁻² at 300 nm, but (+)-circularly polarized luminescence (CPL) with g_lum = +0.84 × 10⁻² at 326 nm. In contrast, iHS in n-octanol at 0 °C showed only very weak (–)-CD of g_abs ~−0.03 × 10⁻² at 310 nm. The H/D isotopes of p-dioxane-h₈/-d₈ weakly affected the helix–helix transition characteristics of iBS. (–)-Sign vibrational CD signals assigned to the handed symmetric and asymmetric bending modes of the CH₃ and CH₂ groups of the solvents and other achiral molecules were observed. We assumed (i) three ¹H nuclear-spin-1/2 induced handed motions of CH₃ rotors at i-alkyl side chains and achiral alkanols, and (ii) helical main-chain Si atoms (δ⁺) coordinated by handed lone pairs at oxygen (δ⁻) in gauche-containing n- and i-alkanols induced by the CH₃ rotors. A possible origin of biomolecular handedness is proposed based on the first observation of far-UV CD and UV spectra of zwitterionic glycine bearing H₃N⁺ rotor in neutral H₂O. Full article