This study presents the synthesis, structural architecture, density functional theory (DFT) investigations, third-order nonlinear optical (NLO) properties, and biological evaluations of two organic–inorganic hybrid compounds based on the dicationic 1-(4-pyridyl)piperazine ligand: (C9H15N3)2+.HgCl42- (Compound I) and (C9H15N3)2+.CuCl42- (Compound II) Single-crystal X-ray diffraction reveals that both hybrid compounds assemble into robust 3D supramolecular networks governed by extensive ionic charge-assisted (N–H···Cl, C–H···Cl) hydrogen bonds. Hirshfeld surface analysis demonstrates that H···Cl (up to 37.1) and H···H contacts dominate the crystal packing. Quantum theory of atoms in molecules (QTAIM), non-covalent interaction (NCI) calculations and Time-dependent DFT (TD-DFT) validate the purely non-covalent character of these lattice-stabilizing interactions. Single-beam Z-scan measurements under continuous-wave excitation show that both complexes exhibit strong reverse saturable absorption (RSA) and thermal self-defocusing behavior. Compound II demonstrates a significantly enhanced third-order susceptibility χ3 = 1.899 × 10–5 compared to Compound I χ3= 1.25 × 10–5 driven by efficient dication-to-halometalate electronic coupling and LMCT interactions. Furthermore, Compound I exhibited pronounced antibacterial efficacy against Escherichia coli 19 mm and S. aureus 21 mm while Compound II demonstrated superior cytotoxic potency against MDA-MB-231 triple-negative breast cancer cells with an IC50 of 10.96 μg/mL (compared to 25.25 μg/mL for Compound I). These results highlight the dual potential of compound I and II in photonic devices and as next-generation anti-cancer therapeutics.
Groundwater faces increasing pressures from climate change, urbanization, land-use change, and emerging contaminants. To assess current challenges, future strategies, and priorities, the international survey “Hydrogeology: Quo vadis…?” gathered responses from the hydrogeology community across four continents. Key concerns included groundwater contamination, impeded recharge and water availability, insufficient regulation of new chemical substances, climate-related extremes, fragmented governance, and limited data accessibility. Strategic priorities focused on strengthening interdisciplinary cooperation, enhancing monitoring and data integration, ensuring sustainable resource allocation, and improving education and public awareness. However, a persistent gap between goal-setting and implementation emerged, driven by weak enforcement, governance and research silos, and resource constraints. To address this gap, seven possible ways forward are outlined: (1) strengthening implementation and enforcement, including improving legislation to protect groundwater; (2) improving cross-level and cross-sector coordination; (3) building networks; (4) investing in education and public engagement; (5) enhancing data integration; (6) tackling emerging challenges proactively; and (7) cultivating political will with long-term resources. The results provide a benchmark for global hydrogeology perspectives and a practical roadmap to advance more effective groundwater governance and protection.
Current research on regional identities does not fully account for the role of regional intergroup dynamics in shaping immigration attitudes. Drawing on insights from the party literature on affective polarization, we argue that not only regional ingroup likes, but also regional outgroup dislikes likely shape attitudes towards other outgroups such as immigrants. We test these arguments in Belgium’s three regions: Flanders, Wallonia, and Brussels-Capital. Using novel survey data, we find that negative feelings toward other regional groups consistently correlate with stronger anti-immigrant sentiment, reinforcing a generalized outgroup rejection. However, the findings for regional ingroup attachment vary: in Flanders and Wallonia, stronger regional identity aligns with exclusionary attitudes, while in Brussels, it is linked to more inclusive views. This study makes three contributions: (1) advancing research on regional affects, (2) demonstrating the role of regional outgroup dislike in shaping migration attitudes, and (3) systematically incorporating Brussels into cross-regional empirical analyses. Our findings highlight the role of subnational identity dynamics in shaping immigration attitudes within multi-level systems.
Dieser Beitrag geht der Frage des Lehrens und Lernens sowie der Beurteilung des Mündlichen im Sprachunterricht aus der Perspektive der Interaktionskompetenz nach. Auf der Grundlage von Interaktionsanalysen aus dem Unterricht und Gespächen mit Lehrpersonen der Sekundarstufe II wird zunächst eine Bestandesaufnahme der Problematik erstellt, wie Lehrpersonen mit dem Unterricht und der Evaluation des Mündlichen einhergeht. Dabei ergeben sich zwei wichtige Mängelbereiche: Zum einen fehlen präzise Deskriptoren für die Evaluation des Mündlichen. Zum anderen besteht ein Mangel an didaktischen Dispositiven, die es erlauben würden klar umrissene Teilkompetenzen – unter Berücksichtigung der eigentlichen Kompetenzniveaus der Schüler – im Unterricht gezielt anzugehen. Angesichts dieser doppelten Diagnose bietet dieser Beitrag abschliessend konkrete Wegweiser hinsichtlich eines strukturierten Unterrichts des Mündlichen sowie der Ausarbeitung klarer, operationeller Evaluationskriterien für die Interaktionskompetenz.
Laser-driven high-Q Kerr-nonlinear optical microresonators enable parametric oscillation with low-power continuous-wave lasers and host a variety of coherent dissipative structures, including dissipative Kerr solitons and switching waves. These time-periodic structures constitute coherent optical frequency combs, and photonic-chip integration has miniaturized them to the chip scale. Such photonic-integrated, microresonator-based frequency combs - often termed 'microcombs' or 'Kerr combs' - have been demonstrated in various system-level and scientific applications. They complement femtosecond-laser-based frequency combs when high repetition rates, broad bandwidths, or high power per comb line are needed. This review introduces the field of microcombs and outlines the fundamental physical principles governing the generation of coherent frequency combs in microresonators.
