Browse Articles

Electrosynthesis of Six-Carbon Acetal from CO₂ Using a Tandem Electrolysis

Photoinduced, Copper-Catalyzed Enantioconvergent Azidation of Alkyl Halides

Activation of Semicore Electrons in Alkali Metals and Their Role in the B1–B2 Phase Transition under Pressure

The Modulatory Role of Positional Isomerism in Diolein on the Structural Features of pH-Responsive 2-Hydroxyoleic Acid Nanocarriers

Functional Al/Cd Heterometallics─From Controlled Al(I) Transfer to Nucleophilic Transfer of Cadmium Ions

Allenes as Stimuli-Responsive Chromophores for Visible to Near-Infrared Optical Modulation

Diversity-Oriented Method Development: Multifunctional Homoallylic Amines and Azabicyclooctanes Bearing a Bridgehead Enamine

Trisilylation of a Formal Cr(−I) Bis-dinitrogen Complex

Late-Stage Serine Modification Enables Noncanonical Peptide Synthesis

Atroposelective Synthesis of Azobenzenes by Palladium-Catalyzed Cross-Coupling of Racemic Biaryl Triflates and Diazenyl Pronucleophiles

Elucidation of Marcus Relationships for Hydride Transfer Reactions Involving Transition Metal Hydrides

Total Synthesis of (−)-Psathyrin A Enabled by Radical Cyclization

Determination of Mn Valence States in Nanocatalysts During Sustainable Syngas Conversion

Fluorinated Deep Eutectic Gel Electrolytes for Sustainable Lithium Metal Batteries

Effects of site elevation and grazing exclusion on phenolic compound production in Nardus stricta plants in high-elevation grasslands

Specialized plant metabolism, particularly phenolic compound production, contributes significantly to the functioning and resilience of mountain ecosystems. Livestock grazing can influence phenolic production, with its effects varying depending on microclimatic factors and soil conditions. Despite the ecological significance of this process, the impact of livestock grazing on phenolic production in alpine plants remains insufficiently explored. To address this knowledge gap, we conducted a field experiment to investigate the individual and combined effects of site elevation and experimental grazing exclusion on phenolic compound production in Nardus stricta plants. After two growing seasons, we collected leaf samples to quantify phenolic diversity and concentration. Site elevation significantly affected phenolic richness and flavonoid concentrations, with higher levels at the highest elevation compared to lower sites. However, livestock grazing exclusion had no significant impact on phenolic concentration, diversity, or any interactions between grazing exclusion and site elevation across sites. This study enhances understanding of plant chemistry and responses to stressors, offering insights into plant adaptations to environmental and land-use changes.

Experimental study on axial compression performance of I-shaped aluminum concrete columns embedded in CFRP-PVC square tubes

To investigate the axial compressive behavior of CFRP-PVC square tube-embedded aluminum concrete columns, five specimens and one control specimen without I-shaped aluminum were tested under uniaxial compression, with the number of CFRP layers and spacing as variable parameters. The failure modes, load-displacement responses, and mechanical properties such as peak load, ductility, stiffness, and energy dissipation were systematically analyzed. Results showed that the incorporation of I-shaped aluminum improved the peak load and ductility by an average of 48.4% and 6.2%, respectively. Increasing the number of CFRP layers increased the bearing capacity by 62.6% for one layer and 69.8% for two layers. Ductility decreased by approximately 15.4% with one layer due to limited confinement but improved by about 15.3% with two layers as the enhanced restraint mitigated stress concentrations and strengthened the composite action. Enlarging the CFRP spacing reduced the bearing capacity by an average of 7.4% but had negligible effect on ductility. The addition of I-shaped aluminum enhanced the axial stiffness by an average of 6.2%, and increasing CFRP layers effectively mitigated stiffness degradation. All specimens exhibited CFRP-PVC or PVC tube rupture and I-shaped aluminum flange buckling, with buckling locations shifting upward as confinement increased. A validated ABAQUS model was used to explore the composite confinement mechanism, and a new confinement model was proposed. The proposed composite columns offer enhanced mechanical performance and durability, making them promising candidates for practical applications in lightweight and high-performance structural elements.

Multiproxy study reveals equality in the deposition of flaked lithic grave goods from the Baltic Stone Age cemetery Zvejnieki (Latvia)

The Stone Dead Project carried out analysis of the flaked lithic assemblages from burial contexts at Zvejnieki cemetery, Latvia. Zvejnieki (c. 7500−2500 cal. BC) represents one of the largest Stone Age burial grounds in Europe, consisting of over 330 burials containing 350 individuals. Using a multiproxy approach, combining geological, technological, functional, spatial and depositional context information, we compare the biographies of lithic grave goods with biographical information (age, sex) of the humans they accompany. Results show gender equality in lithic offerings whilst children are the age group most frequently given lithic grave goods. Certain typologies appear to have carried particular significance and were possibly made, and sometimes broken, as part of funerary rituals. The implications of these and other findings are discussed and placed within their broader archaeological context.

Correction: Insecticidal activity of Bacillus thuringiensis towards Agrotis exclamationis larvae–A widespread and underestimated pest of the Palearctic zone

A hybrid framework of statistical, machine learning, and explainable AI methods for school dropout prediction

Student dropout is a significant challenge in Bangladesh, with serious impacts on both educational and socio-economic outcomes. This study investigates the factors influencing school dropout among students aged 6–24 years, employing data from the 2019 Multiple Indicator Cluster Survey (MICS). The research integrates statistical analysis with machine learning (ML) techniques and explainable AI (XAI) to identify key predictors and enhance model interpretability. Initially, descriptive and inferential statistical analyses were applied to identify significant predictors and guide feature selection. The hybrid feature selection strategy, combining statistical significance and model-based importance measures, revealed key features. Logistic regression was applied to identify statistically significant predictors of school dropout. ML algorithms, Random Forest (RF) and Extreme Gradient Boosting (XGB), were used to build predictive models. Model performance was evaluated using accuracy, precision, recall, and an F1 score. The XGB model achieved the best performance with an accuracy of 94.4%, followed by the RF model. To interpret model predictions and ensure transparency, SHAP (Shapley Additive Explanations) and LIME (Local Interpretable Model-Agnostic Explanations) were employed in tandem with the statistical analyses. Key factors influencing student dropout included age, sex, completed grade, last education grade, division, wealth index, father’s and mother’s education. These insights offer a data-driven foundation for policymakers to develop targeted intervention strategies aimed at reducing student dropout rates and improving educational outcomes in Bangladesh.

Serotonergic receptor binding in the brainstem in the Sudden Infant Death Syndrome in a high-risk population

The Sudden Infant Death Syndrome (SIDS) is a major global health problem, with increased risk among socioeconomically disadvantaged populations. We propose SIDS, or a subset, is due to a defect in the brainstem serotonin system mediating cardiorespiratory integration and arousal. This defect impinges on homeostasis during a critical developmental period in infancy, especially in populations experiencing maternal and infantile stress, resulting in sleep-related sudden death. In the socially disadvantaged cohort of the prospective Safe Passage Study from Cape Town, South Africa, and the Northern Plains of the United States, we tested the hypothesis that: 1) serotonin (5-HT) receptor 1A binding is reduced within the brainstem of SIDS infants compared to controls; and 2) reduced 5-HT1A binding in SIDS is associated with maternal drinking and/or smoking during pregnancy. Using receptor ligand autoradiography for the 5-HT1A receptor, 3H-8-OH-DPAT binding was measured in brainstem nuclei in infants dying of SIDS (n = 14) and controls dying of known causes (n = 10). We found a brainstem serotonin defect in SIDS infants, that is strongly driven by preterm birth, and that likely underlies the pathogenesis of sleep-related sudden death in response to homeostatic stress. The findings replicate studies of US low-to-middle income SIDS cohorts, with key differences related to prematurity, including increased 5-HT1A binding in premature SIDS compared to premature controls. The relationship of the serotonin defect to prenatal smoking and drinking is unclear, owing to the high exposure rates in SIDS cases and controls. SIDS was significantly associated with lack of a phone (proxy for poverty) (p = 0.024) and overcrowded housing (p = 0.047). These data support the concept of a serotonin defect in brainstem nuclei mediating cardiorespiratory control and arousal in SIDS infants. Maternal and/or fetal stress, along with premature birth, may underlie a deflection of normal development of the serotonergic system.