Search Results (1,561)

High-level quantum chemical methods (MRCI+Q and MRCI+P) combined with large correlation-consistent basis sets (aug-cc-pVnZ, where n = Q, 5, 6), were used to investigate the ground-state potential energy curves (PECs) and surfaces (PESs) of the X₂, XO, and X₂O systems (with X = F, Cl, Br). For the triatomic systems, the potential energy data obtained from MRCI+Q/aug-cc-pVQZ calculations in two different Jacobi representations were interpolated using the reproducing kernel Hilbert space (RKHS) method to construct smooth and accurate analytical representations of the PESs. This work provides a detailed comparison of the bonding characteristics of these molecules with those reported in previous studies. It lays the groundwork for future investigations of their dynamics and reactivity. Full article

Bluetooth Low Energy (BLE) resolvable private addresses (RPAs) reduce passive tracking, but RPA-resolving creates receiver-side work: a scanner whose bonded identity set exceeds controller resolving-list capacity which can be forced into repeated host-side Identity Resolving Key (IRK) searches by floods of syntactically valid unknown private-address candidates. We formulate this as capacity-constrained resolving scheduling and propose P3, our persistence-aware admission-control scheduler for BLE RPA resolution, evaluated in its main form P3-Persist. After cache and resolving-list fast paths miss and the unresolved-work budget is exhausted, P3 grants a small reserve only to over-the-air RPA values that reappear. This uses visible repetition rather than an identity-correlated pre-resolution label. In paired simulations, identical visible traces produced identical initial pre-resolution decisions, but later modeled delay/defer features were distinguishable in some tested conditions; accordingly, no end-to-end side-channel-free claim is made. In the evaluated 20-seed, 1800 s simulation matrix (N = 512, RL = 8), P3-Persist keeps modeled unique-flood work in the same bounded approximately 45k AES-equivalent/min regime as budget-only limiting while increasing modeled legitimate resolution to 0.9569 under medium flood and 0.9557 under heavy flood, compared to 0.57–0.62 for budget-only baselines. A 20-seed epoch–loss–density experiment shows that service recovery is conditional rather than universal, and a denser adaptive-address search identifies an overlapping near-cap region around m = 320 and r = 1, with a highest confirmed mean of 146,196.29 AES-equivalent/min (96.69% of the modeled cap). These results establish bounded-work and conditional service-recovery behavior within the simulator; they do not establish production-firmware effectiveness, end-to-end side-channel freedom, on-device timing, energy, current, latency, or queueing behavior. Full article

This study evaluated and compared copper oxide (CuO) and titanium dioxide (TiO₂) nanoparticles (NPs) incorporated into etch-and-rinse adhesives, with and without photoactivation, on microleakage (ML), resin tag length (RTL), micro tensile bond strength (μTBS), and degree of conversion (DC) in caries-affected dentin (CAD). One hundred thirty extracted permanent mandibular molars with occlusal caries (ICDAS 5) were randomly allocated into five groups (n = 26): unmodified adhesive (control); CuO NP-modified (1 wt%); CuO NP-modified with green-light activation; TiO₂ NP-modified (1 wt%); and TiO₂ NP-modified with UV pre-irradiation. Modified adhesives were applied in etch-and-rinse mode and LED-photopolymerized. Micro-hybrid composite build-ups were placed incrementally, and specimens were thermocycled. ML was assessed by dye penetration, RTL by SEM, μTBS by universal testing machine, and DC by ATR-FTIR; fracture modes were classified as adhesive, cohesive, or admixed. Data were analyzed using one-way ANOVA and post hoc Tukey’s. All experimental groups outperformed the control for ML, RTL, and μTBS (p < 0.05). For DC, only the photoactivated groups exceeded control (75.23% and 76.12% vs. 65.22%; p < 0.05); whereas, the non-activated nanoparticle groups did not differ from control. Pre-irradiation of NP-modified adhesives before photopolymerization produced better bonding and marginal sealing, a promising strategy for resin composite restorations. Full article

This study evaluated and compared four irrigation activation protocols—conventional syringe irrigation (CSI), passive ultrasonic irrigation (PUI), photon-induced photoacoustic streaming (PIPS), and shock wave-enhanced emission photoacoustic streaming (SWEEPS)—with 17% EDTA as a final irrigant, with respect to smear layer (SL) removal and push-out bond strength (PBS) of root canal sealer in the apical third of curved root canals. One hundred and twenty extracted single-rooted human premolars with oval canals and moderate curvature (20–40°, Schneider’s method) were allocated into four groups randomly (n = 30 each). Canals were prepared crown-down under 2.5% NaOCl irrigation, followed by final 17% EDTA irrigation per the assigned protocol: CSI, PUI, PIPS, and SWEEPS. 10 specimens per group underwent SEM evaluation of SL removal using Hülsmann’s criteria; remaining specimens were obturated. In 10 samples, apical sealer adaptation was assessed via SEM. PBS of ten samples were evaluated using a universal testing machine, followed by failure mode assessment. Data were statistically evaluated using two-way mixed ANOVA, followed by Tukey’s post hoc test for PBS and Kruskal–Wallis test with Dunn’s multiple-comparison test with Bonferroni correction for SL scores (p < 0.05). Minimum SL removal was exhibited by the apical third of Group 1 (CSI-EDTA) samples. PIPS-EDTA and SWEEPS-EDTA presented comparable SL elimination outcomes in the cervical and middle thirds (p > 0.05). SL elimination between these two groups was significantly different in the apical third. The cervical section of Group 4 displayed the highest bond integrity. However, the lowest bond strength was exhibited by the apical third of Group 1 (CSI-EDTA). SWEEPS combined with EDTA demonstrated superior smear layer removal throughout curved root canals, including the apical third, and yielded the highest push-out bond strength among all tested irrigation protocols. Full article

This review summarizes the methods for the synthesis of α-phosphonocinnamates and their heterocyclic analogs, which have found important applications in materials chemistry, as convenient building blocks in organic synthesis and in other areas of science and technology. Five complementary disconnections are critically compared: (i) Knoevenagel condensation of phosphonoacetates or phosphonoacetic acid with (hetero)aromatic aldehydes and N-tosylimines under amine, amine/carboxylic acid, or amine/Lewis acid catalysis; (ii) arsine-mediated condensation of 2-bromophosphonoacetates with aldehydes; (iii) Mn(III)- or Ag(I)-mediated radical C–P bond formation on cinnamic esters; (iv) phosphine-catalyzed hydrophosphonylation of arylpropiolates; and (v) Heck coupling of aryldiazonium salts with α-phosphonoacrylates. The factors that govern (E)/(Z) selectivity, the substrate scope (electron-rich versus electron-deficient (hetero)arenes), and the chemoselectivity issues encountered with salicylaldehydes—where acyclic phosphonocinnamates, 3-phosphonocoumarins, and [1,2]benzoxaphosphinines (2-phosphacoumarins) compete—are analyzed in detail. A dedicated section covers the synthesis of coumarin-3-phosphonates, including Knoevenagel-type cyclization, Mn(III), Ag(I), Cu or Pd-catalyzed and electrochemical phosphorylation of preformed coumarins, decarboxylative phosphorylation, and intramolecular cyclization strategies. Conflicting literature reports are reconciled where possible, and the practical strengths and limitations of each protocol are highlighted to guide method selection. Full article

Gene delivery with cationic polymers requires balancing DNA compaction, colloidal stability, and intracellular release, yet for imine-linked low-molecular-weight polyethyleneimine (PEI) vectors, quantitative relationships connecting the N/P ratio with the full property–transfection cascade remain undefined. Here, two amphiphilic non-viral vectors were prepared by linking a hydrophobic benzene–siloxane core (TAS) to hyperbranched PEI (800 or 2000 Da) through reversible imine bonds and complexed with DNA across a broad N/P range (10–600). Polyplexes were characterized by atomic force microscopy (AFM), dynamic light scattering (DLS), ζ-potential, agarose gel electrophoresis, transfection via green fluorescent protein (GFP) imaging and luciferase assay in HeLa cells. Both vectors formed spherical nano-entities (AFM diameters ~30 nm for TAS-PEI800; ~100 nm for TAS-PEI2000). TAS-PEI2000 achieved complete DNA retardation at N/P ≈ 30 versus N/P ≈ 150 for TAS-PEI800, consistent with its higher charge density (ζ = +37.59 vs. +18.35 mV). Transfection efficiency was superior for TAS-PEI2000 across most N/P ratios; however, TAS-PEI2000 displayed an optimal transfection efficiency at N/P ≈ 100 (ζ ≈ 3.84 mV), beyond which efficiency declined, indicating a binding–release trade-off. Cell viability remained >77% across the N/P range for TAS-PEI800, but dropped below 25% at N/P ≥ 400 for TAS-PEI2000. A phenomenological logistic model identified characteristic transition thresholds (θ ≈ 60 for TAS-PEI800; θ ≈ 40 for TAS-PEI2000), capturing the onset of cooperative self-assembly; however, the post-optimum decline observed for TAS-PEI2000 requires additional inhibitory terms. These findings demonstrate that PEI molecular weight governs both the N/P threshold required for efficient transfection and the width of the therapeutic window, thereby providing structure–activity descriptors for the rational design of imine-linked polyplex systems. Full article

Nelumbo nucifera Gaertn. is a rich source of bioactive compounds, and has been extensively investigated for its antioxidant and anti-inflammatory properties. However, despite its broad pharmacological potential, detailed molecular-level insights into the interactions of its phenolic and flavonoid constituents with key skin-aging-related enzymes remain limited. Therefore, this study employed an integrated in silico and in vitro approach to systematically evaluate the anti-aging potential of phenolic and flavonoid compounds derived from N. nucifera. Molecular docking was performed to investigate their binding interactions with tyrosinase, elastase, and collagenase. Compounds exhibiting the most promising inhibitory profiles were further subjected to molecular dynamics (MD) simulations for 100 ns and density functional theory (DFT) analyses at the B3LYP/6-31G(d,p) level of theory to elucidate their structural stability and electronic properties. The computational results revealed favorable binding affinities, stable complex formation, and electrostatic features supporting hydrogen bond interactions. In vitro enzyme inhibition assays demonstrated that hesperidin exhibited inhibitory activity against tyrosinase, collagenase, and elastase, with IC₅₀ values of 3.43 mM, 2.26 mM, and 0.55 mM, respectively. Kojic acid was used as a positive control for tyrosinase, while epigallocatechin gallate (EGCG) was used as a positive control for both collagenase and elastase. Additionally, hesperidin exhibited enzyme-inhibitory activity and preliminary intrinsic UV absorption. This compound warrants further investigation, specifically regarding its stability and performance within standardized cosmeceutical formulations. Full article

Selective laser melting (SLM) and electron beam melting (EBM) enable the fabrication of commercially pure titanium, but the effects of the fabrication method and build orientation on surface characteristics and bonding remain unclear. This study evaluated the surface roughness, wettability, and shear bond strength of titanium fabricated by SLM and EBM at build orientations of 0°, 45°, and 90°, with titanium ingots intended for dental casting serving as reference specimens. The surfaces were wet-ground, air-abraded with 50 µm alumina particles, and treated with a 10-methacryloyloxydecyl dihydrogen phosphate-containing metal primer. Surface roughness (Sa), static water contact angles before and after primer application, and shear bond strength to a resin luting agent after 24 h of water storage were evaluated (n = 15/group). The EBM specimens fabricated at 90° exhibited significantly greater Sa values than the other groups (p < 0.05). Primer application significantly increased the water contact angle in all groups (p < 0.05), although group-dependent differences were observed. No significant differences in shear bond strength were detected among the fabrication conditions (p > 0.05). Thus, under the tested surface treatment conditions, differences in surface roughness and wettability were not accompanied by corresponding differences in the initial bond strength of commercially pure titanium. Full article

Achieving an acceptable adhesive interface is necessary for the long-term success of composite restorations in primary teeth. This study compared the three-dimensional internal adaptation of composite restorations in primary second molars among four prespecified universal adhesive product–application protocol combinations using micro-computed tomography (micro-CT). Seventy-six extracted primary second molars were randomly allocated to four experimental groups (n = 19): G2-BOND Universal/self-etch, G2-BOND Universal/selective enamel etching, G-Premio Bond/self-etch, and G-Premio Bond/selective enamel etching. Following restoration and thermocycling (5000 cycles), whole-cavity interfacial gap volume percentages were quantified using micro-CT. Data were analyzed using the Kruskal–Wallis test followed by Dunn–Bonferroni-adjusted pairwise comparisons. An overall difference was detected among the four experimental groups (p = 0.016). Following adjustment for multiple comparisons, the G2-BOND Universal self-etch group showed a lower whole-cavity interfacial gap volume percentage than the corresponding selective enamel-etching group (adjusted p = 0.013). No other adjusted pairwise comparison reached statistical significance. Within the limitations of this laboratory study, these findings are restricted to the tested product–application protocol combinations and do not demonstrate an interaction between adhesive system and application mode. Full article

Green finance has emerged as a critical mechanism for aligning capital markets with climate and sustainability objectives, particularly as economies face mounting pressure to transition away from carbon-intensive growth models. In hydrocarbon-dependent regions such as the Gulf Cooperation Council (GCC), this transition poses distinctive challenges that require integrated institutional, policy, and financial frameworks. The global transition toward sustainable finance has gathered significant momentum, with green capital markets emerging as a central mechanism for channeling investment toward climate and development objectives. Hydrocarbon-dependent economies face a distinctive challenge in this transition, as they must reconcile resource-based growth models with rising pressures for environmental accountability and low-carbon diversification. This study develops an integrated theoretical framework to examine how Gulf Cooperation Council (GCC) financial systems are transitioning toward green capital markets, drawing on institutional theory, environmental policy pathway analysis, and climate-finance alignment models. Using descriptive statistics from regional stock exchanges covering 2015–2024, the study maps key trends in sustainable asset growth, institutional investor preferences, and regulatory evolution across the GCC. Findings indicate progressive alignment with global ESG norms; sustainable asset valuations grew at 23.5% CAGR (UAE) and 18.7% CAGR (Saudi Arabia). A fixed-effects panel regression with panel-corrected standard errors is estimated across all six GCC economies; regulatory framework maturity emerges as the strongest predictor of green bond issuance (β = 0.47, p < 0.01). Cumulative green bond issuances reached USD 52.6 billion (2015–2024), with renewable energy accounting for 58.1% of the sectoral allocation and green transportation recording a 55.9% CAGR (2020–2024). Policy recommendations focus on GCC-wide harmonization of mandatory ESG disclosure, adoption of a unified green bond taxonomy, and expansion of concessional green financing mechanisms. Substantial cross-country heterogeneity is documented, driven by differences in energy policy commitment, financial market maturity, and institutional capacity. The proposed framework offers specific policy guidance to accelerate green financial integration in the GCC, emphasizing regulatory harmonization, institutional capacity-building, and alignment with SDG targets 7 and 13. The study contributes to the limited evidence base on green finance in hydrocarbon-dependent economies and provides a foundation for future empirical research. Given the small panel dimensions (N = 6 cross-sectional units; T = 10 years), this study is positioned as exploratory rather than confirmatory: the panel-regression estimates and the hypothesized institutional-to-policy-to-finance sequence are interpreted as associational patterns consistent with the proposed framework rather than as definitive causal tests, and the reported coefficients are offered as indicative magnitudes to be re-examined as longer GCC green-finance time series become available. Full article

Herein, we report an unexpected pseudo-multicomponent transformation discovered during attempts to selectively nitrate the pyridine core of 3-acetyl-2,4,6-trimethylpyridine (3). Despite employing standard nitration conditions, including KNO₃–H₂SO₄ and HNO₃–H₂SO₄ mixtures, electrophilic substitution of the aromatic ring did not occur. Instead, the reaction sequence promoted an in situ nitrozation, dehydration to nitrile oxide intermediates, and subsequent [3+2]-cycloaddition involving two substrate molecules. This process yielded a novel, highly functionalized furoxan derivative, precisely identified as 3,4-bis(2,4,6-trimethylnicotinoyl)-1,2,5-oxadiazole 2-oxide (5). The molecular architecture of compound 5 was established by ¹H and ¹³C NMR spectroscopy, mass spectrometry, elemental analysis, and single-crystal X-ray diffraction (XRD) analysis. To elucidate the stereochemical and electronic features governing compound 5, DFT calculations were performed at the ωB97X-D/6-311++G(d,p) level of theory. The experimental crystallographic disorder of the N-oxide oxygen atom was computationally rationalized by the thermodynamic near-degeneracy (ΔG < 0.63 kcal/mol) of two orientational isomers (5a and 5b). Furthermore, frontier molecular orbital analysis within the framework of perturbation theory accounted for the head-to-tail regioselectivity during cyclization, while wide energy gaps (ΔE = 8.13–8.27 eV) and high chemical hardness (η = 4.07–4.14 eV) underscored the kinetic stability of the heterocycle. Phenotypic and target-specific in silico profiling using PASS Online identified Matrix Metalloproteinase-9 (MMP-9) as a relevant target for potential hemorheological and cardioprotective applications. Validated molecular docking simulations across three human MMP-9 crystallographic domains (PDB: 8K5Y, 6ESM, 4XCT) demonstrated competitive binding affinities and balanced Ligand Efficiency metrics (LE = 0.26–0.29 kcal/mol/heavy atom), anchoring compound 5 within the catalytic pocket via conventional hydrogen bonds and π-mediated interactions. Finally, in vitro evaluations using a blood hyperviscosity model confirmed significant hemorheological efficacy, as compound 5 effectively prevented the rise in blood viscosity, outperforming the reference drug pentoxifylline. The convergence of computational insights and experimental functional activity establishes this novel bis(nicotinoyl)furoxan framework as a promising candidate for further hemorheological and cardioprotective applications. Full article

The electrochemical regeneration of sodium borohydride (NaBH₄) from spent metaborate is a central bottleneck for circular hydrogen storage. (1) Background: The eight-electron reduction of the aqueous borate species B(OH)₄⁻ to BH₄⁻ is thermodynamically out-competed by the hydrogen-evolution reaction (HER) by about 0.41 V at every pH, so selectivity can only be won kinetically. (2) Methods: We advance an ambiphilic-site hypothesis, screen 30 candidate metal centres using entirely experimental, tabulated descriptors (bulk HER exchange current density; gas-phase M-O bond energy) with no new electronic-structure computation, and then audit the transferability of both descriptor axes against published, corrected DFT datasets for nitrogen-coordinated single-atom sites. (3) Results: At the parent-metal level, the two axes are orthogonal (Spearman ρ = 0.02) and the score passes a family-level experimental validation over seven bulk-electrode metals (ρ = 0.69; exact permutation p = 0.050), separating the HER-dominated noble-metal family from the single-atom Mn benchmark. The site-level audit shows that the oxophilicity axis transfers to M-N₄ sites almost quantitatively (ρ = −0.84 pyridine-4N, −0.95 pyrrole-4N, n = 23) while the bulk HER axis does not, and that site-level scaling between oxygen and hydrogen binding narrows the productive window to oxophilic centres that over-bind hydrogen. (4) Conclusions: The site-anchored screen redirects the search from the parent-metal leaders (La, Ce, Y, Ti, Sc) to refractory single-atom centres, with W, Nb and Mo as priority synthesis targets (Re excluded on scarcity; Zr, Hf, Ta as data-supported extensions; Ti as the sustainability-anchored borderline case) and the lanthanides retained only as explicitly extrapolative candidates. All data and analysis code are openly deposited. Full article

This systematic review evaluated the effects of functional additives on fluoride release, fluoride recharge/re-release, and selected mechanical, physical, and biological properties of orthodontic glass ionomer cements (GICs) and glass ionomer-based adhesives. The review followed PRISMA guidelines. The protocol was retrospectively registered in the Open Science Framework. PubMed, Scopus, Web of Science, Embase, and WorldCat were searched for in vitro studies investigating modified orthodontic GICs and reporting fluoride-related or clinically relevant material properties. The final literature search was conducted on 30 April 2026. After screening 87 records, 23 studies were included in the qualitative synthesis. Owing to substantial methodological and outcome heterogeneity among the included studies, no meta-analysis was performed, and the findings were synthesized narratively. Risk of bias was assessed using the QUIN Tool; 20 studies were classified as having a medium risk of bias and three as having a low risk, while none were classified as having a high risk. The effects of additives on fluoride release varied according to additive type and concentration, material composition, storage conditions, pH, and evaluation period. Increases in fluoride release were reported in studies evaluating materials containing nCaF₂, TMPnano, nanofluorapatite or nanofluorohydroxyapatite, hydroxyapatite, nanochitosan, SNP/ZnONP, and ZnSO₄. Several additives maintained or improved mechanical performance, whereas higher concentrations of some agents adversely affected bond strength, microhardness, or material stability. Antibacterial and antibiofilm activity was most evident for CHX, DMAHDM, MDPB, propolis, silibinin, nanosilver, and zinc-containing systems. Limited evidence also suggested potential benefits regarding enamel protection and cytocompatibility. Functional additives may enhance the preventive potential of orthodontic GIC-based materials, particularly through improved fluoride release and antibacterial activity. However, further standardized long-term and clinical studies are required before clinical recommendations can be made. Full article

(1) Background: This study aimed to assess how two different adhesive solvent evaporation techniques affect the microtensile bond strength (µTBS) of a universal adhesive to dentin, as well as the enzymatic activity of dentinal matrix metalloproteinases (MMPs) at baseline and after 6-month aging under simulated pulpal pressure. (2) Methods: Middle-depth dentin surfaces of 32 sound extracted human molars were bonded under simulated pulpal pressure using a universal adhesive (Clearfil Universal Bond Quick) in either etch-and-rinse (ER) or self-etch (SE) mode. Two solvent evaporation approaches were compared: evaporation with a disposable air/water syringe (air) and with a disposable suction device (suction), yielding four experimental groups (n = 8): ER/air, ER/suction, SE/air, and SE/suction. After light-curing for 10 s, a 4 mm composite build-up was created. Specimens were stored in distilled water under simulated pulpal pressure at 37 °C for either 24 h (T0) or 6 months (T6) and then sectioned into sticks and subjected to µTBS testing. Fracture surfaces were examined by scanning electron microscopy (SEM). An additional subset of teeth from each group (n = 3) underwent in situ zymographic analysis, in which bonded sticks were ground and exposed to fluorescein-conjugated gelatin, with enzymatic activity quantified by confocal microscopy. Statistical analysis was performed at a significance threshold of p < 0.05. (3) Results: Air-drying yielded significantly higher µTBS values than suction drying, irrespective of adhesive application mode (p < 0.05). At T6, SE groups retained bond strength values comparable to baseline (p > 0.05), whereas ER groups showed a significant reduction in bond strength with aging (p < 0.05). The ER mode and suction were associated with significantly increased MMP activity at T0 (p < 0.05), while there were no differences between SE/ER at T6 (p > 0.05), and air increased MMP activity (p < 0.05). (4) Conclusions: When using an ethanol-based universal adhesive under pulpal pressure, evaporation with a disposable air syringe combined with the self-etch application mode appears to offer greater bonding reliability and stability. Full article

This in vitro study evaluated the effect of two silane coupling agent application techniques (dry air and thermally activated warm air) on the interfacial properties and shear bond strength (SBS) of lithium disilicate veneers fabricated with two designs: incisal overlap and window. Materials and Methods: The interfacial characteristics of lithium disilicate specimens were evaluated using contact angle measurements and ATR–FTIR spectroscopy to investigate the effect of different silane application techniques. Forty lithium disilicate veneer specimens were divided by preparation design (incisal overlap or window) and silane application technique (dry air or warm air) (n = 10). Forty flat lithium disilicate specimens were prepared for contact angle and ATR–FTIR analyses. Wettability was assessed using the sessile drop method, while SBS was measured using a universal testing machine. ATR–FTIR evaluated chemical changes within the silane layer. Results: Warm-air silane application significantly improved SBS and wettability compared with dry-air application. The incisal overlap/warm-air group exhibited the highest SBS (19.3 ± 1.7 MPa), whereas the window/dry-air group showed the lowest (12.5 ± 1.4 MPa). Contact angle measurements demonstrated significantly lower values following thermal activation (p < 0.001). ATR–FTIR analysis suggested modifications in carbonyl-containing organic species at the interface following thermal activation. Conclusions: Thermal activation of silane improved interfacial properties and bond strength. Incisal overlap preparations demonstrated superior bonding performance, while warm-air silane application enhanced adhesion across both designs. Full article