Search Results (391)

1-Deoxynojirimycin (DNJ), a well-characterized α-glucosidase inhibitor, remains an important target for dose-reduction and formulation strategies. In the present study, we evaluated the individual and combined α-glucosidase inhibitory activities of nine dietary flavonoids with DNJ, quantified synergistic effects using the combination index (CI) method, and elucidated the molecular mechanism through integrated enzyme kinetics, multi-spectroscopic techniques and molecular docking. (+)-Catechin exhibited the strongest inhibitory activity (IC₅₀ = 33.7 ± 2.7 μM), and its combination with DNJ produced synergistic inhibition across all doses (CI < 0.7). Kinetic analysis confirmed that DNJ acted as a competitive inhibitor, while (+)-catechin functioned as a non-competitive inhibitor. Fluorescence quenching assays revealed that (+)-catechin pre-incubation increased the binding affinity of DNJ to α-glucosidase by 393%. Circular dichroism spectroscopy showed that (+)-catechin induced a marked β-sheet-to-α-helix conformational conversion, and co-incubation of both inhibitors produced more secondary structural changes than either inhibitor alone. Molecular docking further confirmed their distinct binding sites. These findings demonstrate that (+)-catechin synergistically potentiates DNJ activity through allosteric conformational modulation, providing an experimental basis for optimizing DNJ-containing formulations. Full article

This paper mainly investigates the ice-impact resistance of PVC foam sandwich beams for polar ship protective structures through low-velocity impact experiments and nonlinear finite element simulations. An experimentally validated elastic–plastic coupled model, accounting for ice crushing and large structural deformation, was used to examine the effects of core density and face-sheet thickness distribution on the ice-impact response of sandwich beams. Results show that the upper face sheet undergoes local indentation and global bending, the lower face sheet mainly bends globally, and the foam core exhibits local compression and overall bending, while compressive deformation accompanied by ice crushing and spalling occurs at the front part of the ice impactor. Moreover, the effective structural stiffness decreased during plastic loading as local indentation and core compression developed, whereas the unloading stiffness was higher than the effective stiffness during plastic loading. Energy dissipation primarily comes from ice crushing, face-sheet plasticity, and core compression. Increasing core density reduces deflection and core compression but increases peak force. Among the three face-sheet configurations examined at a constant total thickness, the configuration with a thinner upper face sheet and a thicker lower face sheet produced a smaller final deformation of the lower face sheet. This study provides a useful reference for ice-resistant design of sandwich structures in polar ships. Full article

Phanera sirindhorniae (formerly known as Bauhinia sirindhorniae) is a Thai medicinal plant with reported traditional use for the treatment of inflammation; however, its comprehensive phytochemical, biological, and formulation potential remains underexplored. This study aimed to evaluate the phytochemical composition, antioxidant, anti-inflammatory, and antimicrobial activities of extracts from the flower (BSFE), stem (BSSE), and leaf (BSLE), and to develop a BSLE-loaded hydrogel sheet for topical application. Among the extracts, BSSE exhibited the highest total phenolic content (503.71 ± 7.56 mg GAE/g) and total flavonoid content (4778.67 ± 255.47 mg EGCG/g), along with strong antioxidant activity, as demonstrated by DPPH (IC₅₀ = 17.05 µg/mL) and FRAP assays. BSLE showed superior anti-inflammatory activity by significantly suppressing nitric oxide and pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) in LPS-stimulated RAW264.7 macrophages, whereas BSSE displayed moderate effects. In antimicrobial evaluation, BSSE exhibited the strongest activity among the extracts, particularly against Escherichia coli and Staphylococcus species, although its potency remained lower than that of standard antibiotics. HPLC analysis identified 3,4-dihydroxybenzoic acid and luteolin as characteristic anti-inflammatory markers in BSLE. Based on its promising anti-inflammatory activity, BSLE was incorporated into hydrogel sheets (BSLE-F1 and BSLE-F2) using HPMC/PVA matrices with varying PEG 600 content. Both formulations demonstrated suitable physicochemical properties and skin-compatible pH. BSLE-F2 showed improved water retention and dimensional stability, whereas BSLE-F1 exhibited superior peelability, swelling capacity, and tensile strength. In conclusion, BSLE-F1 demonstrated a more favorable balance of mechanical and functional properties, suggesting its suitability as a topical anti-inflammatory hydrogel sheet. This study highlights the potential of P. sirindhorniae extracts for developing multifunctional, natural-based topical delivery systems. Full article

Antarctic microorganisms experience persistent subzero temperatures and repeated freeze–thaw cycles that require specialized mechanisms for survival. Although transcriptomic studies have identified numerous cold-responsive genes, many remain annotated as hypothetical proteins with unknown functions. In this study, we investigated PL002-1792, a strongly upregulated hypothetical protein from Antarctic Flavobacterium sp. PL002 identified under severe cold stress (−20 °C versus −6 °C; log₂ fold change = 5.61, adjusted p = 1.89 × 10⁻¹³⁸). Sequence analysis revealed a 402-amino-acid protein containing a predicted Sec/SPII lipoprotein signal peptide. AlphaFold3 prediction generated a high-confidence structural model (pTM = 0.96) with an elongated β-sheet-rich architecture resembling bacterial ice-binding proteins. Comparative analysis with the ice-binding protein from Flavobacterium frigoris (FfIBP) identified conserved glycine-rich and TXT-like motifs associated with putative ice-binding surfaces. Recombinant PL002-1792 was expressed in Escherichia coli, recovered from inclusion bodies, and successfully refolded into a predominantly β-sheet-rich conformation as confirmed by circular dichroism spectroscopy. Functional assays demonstrated moderate ice recrystallisation inhibition activity, reducing relative ice crystal mean grain size to approximately 90% of the control, and significantly enhanced freeze–thaw survival, with recombinant cells retaining 67% viability after three freeze–thaw cycles compared with 27% for the empty-vector control. These findings identify PL002-1792 as a novel antifreeze-like protein and highlight the utility of structure-guided approaches for uncovering previously uncharacterized cold-adaptation mechanisms in polar microorganisms. Full article

The varying sensibilities of diverse proxies to Indian Summer Monsoon (ISM) variables lead to inconsistencies across individual studies. To attain a comprehensive understanding of the ISM driving mechanisms, it is essential to compile multi-proxy paleorecords from diverse monsoon-influenced areas. However, terrestrial ISM records spanning the last 200 ka remain sparse. Here, we performed a magnetic analysis of the PT2 core lacustrine sediments from the Heqing Basin, covering the past 184 ka, to reconstruct ISM variations from millennial to orbital timescales. According to the rock magnetic results, samples displaying strong magnetization are dominated by substantial amounts of magnetite and maghemite, accompanied by a broad grain-size distribution. Conversely, samples with weak magnetization show only limited quantities of fine-grained magnetite. The decrease in magnetic mineral concentration is attributed to the reduction in both coarse and fine-grained particles. Magnetic mineral dissolution intensity (MMDI) which combines magnetic susceptibility and frequency-dependent magnetic susceptibility, is highly sensitive to ISM changes. Consequently, we derived an ISM index from the MMDI and geochemical indicators of the PT2 core lacustrine sediments. This index exhibits pronounced “glacial–interglacial variations”, aligning with other regional ISM indicators from southwestern China and a variety of ISM-related proxies from a broader range of ISM-influenced areas. This suggests that ISM intensity is more sensitive to glacial boundary conditions in high-latitude ice sheets. Full article

A long-term, consistent dataset of blowing snow (BLSN), a common phenomenon over Antarctica, is essential for ice sheet mass balance analysis. While space-borne lidar missions such as Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) and Ice, Cloud, and Land Elevation Satellite (ICESat-2) have provided valuable continental-scale BLSN observations, their temporal resolutions and spatial reaches present notable limitations. Using CALIPSOs for training, a machine learning approach has been developed to generate hourly Antarctic BLSN data on the Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2) grid, extending back to the 1980s. ICESat-2 observations are used to assess the post-CALIPSO period; the results demonstrate greater bias with BLSN layer heights and better agreement with BLSN fraction and optical depth. When compared with ground-based observations, MERRA-2 exhibits a comparable and lower BLSN fraction and lower layer heights than those recorded by ceilometers. This data record represents the longest continuous BLSN data record to date. This study provides an overview of key BLSN properties, including occurrence, height, and optical depth. The results highlight strong seasonal patterns: BLSN occurrence peaks during Antarctic winter, while both height and optical depth are higher in summer with no statistically significant trend. Spatially, East Antarctica exhibits higher BLSN occurrence than West Antarctica. Full article

Natural coumarins are a structurally privileged group of bioactive benzopyranone lactones widely spread across the Apiaceae, Rutaceae, and Leguminosae families, and hold significant potential as inhibitors of pathological protein aggregation in Alzheimer’s disease, Parkinson’s disease, and type 2 diabetes mellitus. The fully planar, rigid bicyclic structure of the coumarin nucleus (~3.4–3.5 Å thickness) is geometrically compatible with intercalative π–π stacking with aggregation-nucleating aromatic residues, including Phe19 of Aβ(1–42), providing a mechanistically coherent pharmacophoric basis for anti-aggregation activity according to computational and indirect biophysical evidence. This review critically evaluates the peer-reviewed literature on naturally occurring coumarins and their synthetic derivatives as candidate β-sheet intercalators, with analysis of SAR at C-3 to C-8 positions; multi-target-directed ligand designs with dual activities of inhibiting AChE, BACE-1, GSK-3β, and MAO-B, and as blood–brain barrier-penetrating neuroprotective agents validated in cellular and rodent models. The critical analysis identifies the translational gap between in vitro IC₅₀ values and attainable brain drug concentrations as the primary pharmacological obstacle. It identifies the absence of systematic investigation of coumarin against IAPP, a directly relevant amyloid target in metabolic neurodegeneration, as the most significant unmet research priority in the field. Full article

Ice recrystallization inhibition (IRI) activity of peptides is influenced by both peptide length and secondary structure; however, whether combinations of peptides with different lengths exhibit cooperative or antagonistic effects remains poorly understood. Using molecular dynamics simulations, this study investigated how secondary structure and chain-length heterogeneity jointly affect the IRI activity of peptide-pair mixtures. For systems containing only β-sheet-rich peptides, mixtures of different chain lengths consistently reduced ice content relative to the corresponding single-peptide systems, suggesting cooperative enhancement of IRI activity. In contrast, individual α-helical peptides showed strong inhibition of ice growth, but this effect was diminished after they were mixed into peptide pairs. Structural analyses suggested that the improved performance of β-sheet mixtures was associated less with the simple preservation of native β-sheet structure than with mixing-induced changes in peptide–peptide coupling and surface exposure. By contrast, helix-containing mixtures retained more of their original local structure in some cases, but this structural retention was not accompanied by improved ice-growth suppression after mixing. Together, these findings suggest that peptide length effects on IRI are not universally synergistic but depend strongly on secondary-structure compatibility. Full article

Ice-dammed lakes were common along the southern margin of the Laurentide Ice Sheet during deglaciation. In the Schoharie Valley of the northern Catskill Mountains, New York, a 171 km² lake known as glacial Lake Grand Gorge formed in an interlobate area. Previous researchers suggested that deltas developed into this glacial lake from meltwater supplied by the adjacent Hudson Lobe during deglaciation. This study investigates stratigraphy and sedimentology of Pleistocene deltas and lake deposits to determine the source of meltwater and sediment. Detailed examination of stratigraphy from quarries, stream exposures, and new exploration borings was combined with radiocarbon and OSL geochronology to establish event stratigraphy. Sedimentologic and geomorphic data from deltas in the Manor Kill and Platter Kill Valleys demonstrates that braided outwash was supplied directly from the Westerlo Sublobe that crossed the northeastern escarpment of the Catskill Mountains. New geochronologic data indicates that the lake was established by 28 ka and likely persisted to at least 22 ka. Insects and twigs recovered from lake sediments complement the OSL data and indicate: (1) that the lake was present significantly earlier than previous deglacial models predict, and (2) that it existed in an ice-free area of the northern Catskill Mountains during the last glacial maximum of the MIS 2 glaciation. Full article

Antarctic drilling projects provide critical information for investigating ice-sheet stability, reconstructing paleoclimate evolution, and characterizing subglacial geological structures through ice-core and bedrock recovery. Drilling site selection currently relies on high-resolution geophysical methods such as radio echo sounding and active-source seismic methods; however, radar imaging near the ice–bedrock interface is limited by electromagnetic attenuation, while active-source seismic methods in polar regions are constrained by logistical complexity and high cost. To address these limitations, this study proposes a passive integrated imaging approach that integrates P-wave responses and vertical-component Rayleigh-wave information retrieved from continuous ambient noise recordings near drilling sites using seismic interferometry. Based on their distinct propagation characteristics, signal selection and processing workflows are developed to jointly image near-surface firn structure, ice-sheet thickness, and subglacial bedrock structure. Application to the Princess Elizabeth Land drilling project in East Antarctica demonstrates that high- signal-to-noise-ratio P-wave responses and vertical-component Rayleigh-wave signals can be retrieved from as little as 24 h of ambient noise data, while stacking the full 20-day record further suppresses incoherent noise and yields more reliable imaging of the ice–bedrock interface. These results indicate that passive seismic imaging provides a rapid, cost-effective, and environmentally friendly complement for drilling site selection and operational support. Full article

In the northeastern United States, sediments related to the expansion and contraction of the Laurentide ice sheet have been extensively mapped throughout New England, as well as in New Jersey and on Long Island. However, linking these deposits around New York City is challenging due to the extensive urbanization. Staten Island is less developed than the other boroughs of New York City, however outcrops of rock and surface sediment are limited, making interpretation of its geologic history challenging. When small areas of sediment are temporarily exposed, they can be used to improve our understanding of sediment erosion and deposition over time, helping to link the deposits mapped in New Jersey and Long Island. In this study of two small temporary outcrops, the beds of sediment were measured and described in the field and samples were collected for textural and compositional analyses. The results were interpreted in the context of previous work on similar exposures nearby. The sediments are sands and gravels of fluvioglacial origin containing reworked sediments of both the Pliocene Pensauken Formation and older Triassic rocks of the Newark Basin, interpreted to have been deposited on an outwash plain during the Illinoian glaciation (Marine Isotope Stage 6). They were deposited in a topographic low directly overlying Cretaceous sedimentary rocks, but adjacent to sediments of the Pensauken Formation which had in turn been deposited as an earlier valley fill. Similar sequences of repeated valley fills have been observed in New Jersey but have not been documented on Staten Island. This interpretation solves an apparent disagreement between previous studies by illustrating how both the Pensauken Formation and later fluvioglacial sediments can directly overly Cretaceous sediments across a distance of less than a kilometer. Full article

East Antarctica is composed of a composite Precambrian shield largely covered by a thick ice sheet. Information on the thermal structure of the East Antarctic lithosphere is critical to the understanding of the geological history and ice sheet dynamics of this region. To better describe the lithospheric thermal structure, Curie-point depths are first estimated through the inversion of aeromagnetic anomaly data using the wavenumber-domain centroid method, and the Curie point estimates is further employed to determine a lithospheric thermal thickness model by integrating the 1D steady-state heat conduction equation. Our results show that the variations in both the Curie-point depth and thermal thickness estimates have strong spatial consistency with known major geological provinces, such as ancient cratons and younger orogens. Moreover, our findings show a hot and thin lithosphere in the Gamburtsev Subglacial Mountains and Dronning Maud Land, whereas a cold and thick cratonic lithosphere is found in the Wilkes and Aurora Subglacial Basins and the hinterland of Enderby Land. A few local-scale thermal anomalies are also observed in cratonic areas, indicating that some of these areas have lost their cratonic signature. The new thermal thickness model provides direct constraints that can be used to trace early tectonic–thermal activities in East Antarctica. Full article

This work describes the fabrication and characterization of a novel lateral 4H-SiC PiN diode featuring inter-device isolation technology for power integrated circuits (ICs). The device’s architecture includes thick SiO₂ blocking layers and inter-device trench isolation structures, enabling effective electrical isolation between power devices and control circuitry on a single chip. The devices demonstrate good isolation performance, with inter-device leakage currents below 5 nA at a reverse bias of 200 V. The diodes keep reverse leakage current low (<1 μA at 20 V), but exhibit non-distinct turn-on behavior. This is mostly due to the too-shallow N+ and P+ ion implantation region and high series resistance. A monolithically integrated bridge circuit operating at 50 Hz and 200 Hz validates the integration approach; however, large forward voltage drops show that the high series resistance at the device level affects overall conversion efficiency. The transfer length method (TLM) characterization reveals high sheet and contact resistances, which are responsible for the conduction limitations in the PiN diode forward performance. This study establishes the foundation for a lateral SiC device technology with promising inter-device isolation capabilities, as well as the bridge circuit built based on the lateral PiN diodes, which shows the potential of this technology for future monolithic power IC applications. Full article

Pancreatic lipase (PL) inhibition is a promising dietary strategy for obesity management. In this study, the inhibitory mechanisms and structural basis of polyphenols extracted from different sugarcane fractions were investigated using in vitro enzyme assays, spectroscopy, and molecular docking analyses. PL inhibitory activity was evaluated using p-nitrophenyl laurate (pNPL) as the substrate, with all assays performed in triplicate and results statistically analyzed. Among the extracts, sugarcane peel polyphenols (SP) exhibited the strongest inhibition, with a half-maximal inhibitory concentration (IC₅₀) of 31.56 mg/mL, significantly lower than that of sugarcane juice polyphenols (SJ, 55.86 mg/mL) and sugarcane bagasse polyphenols (SB, 65.31 mg/mL). Enzyme kinetic analyses revealed a reversible mixed-type inhibition mechanism. In contrast to crude extracts, individual phenolic monomers showed substantially lower IC₅₀ values (0.13–1.33 mg/mL), highlighting the intrinsic dilution. Compositional analysis identified ferulic acid, gallic acid, chlorogenic acid, and schaftoside as key contributors to PL inhibition. Fourier transform infrared (FTIR) and fluorescence spectroscopy demonstrated that polyphenols altered PL secondary structure by modulating α-helix and β-sheet contents and perturbed the microenvironment of tryptophan (Trp) and tyrosine (Tyr) residues. Molecular docking further indicated that these compounds bind within or near the substrate-binding channel via hydrogen bonding and hydrophobic interactions, engaging critical residues including Ser152, His263, and Phe77, and potentially influencing conformational elements involved in active-site accessibility. Collectively, these results suggest that sugarcane, particularly its peel, represents a valuable natural source of PL inhibitors. Despite the relatively high IC₅₀ values of crude extracts, their inhibitory activity arises from multicomponent contributions and supports their potential application as dietary modulators of fat digestion rather than as pharmaceutical lipase inhibitors. Full article

Aligned CS/Rx aerogels were fabricated by inducing non-directional ice growth (freeze-molding) followed by low-temperature curing, resulting in monoliths with interconnected channels, a high void fraction, and moldability. The swelling index (S%) was calculated to be 1029, the apparent density 0.496 g·cm⁻³, and the estimated porosity 90% based on micrographic analysis. Aerogels have mechanical behavior Shore A hardness greater than 25. Batch metal removal tests were performed (10 mL, 100 mg·L⁻¹ Cr(VI), 0.19 g adsorbent, 24 h, and pH 5–5.5), and the material achieved 95% metal removal. Additional kinetic and isothermal results were obtained using CS85R15 on a packed column (20 to 140 mg·L⁻¹, 1000 mL Cr(VI), 0.80 g adsorbent, 24 h, and pH 5–5.5). Equilibrium data were consistent with a heterogeneous surface hosting a specific site, as reflected in the joint Freundlich/Langmuir fit (q_max 100.8 mg·g⁻¹ for Langmuir). This confirmed the preservation of chitosan functionalities (–OH/–NH) after processing, while XPS detected chromium on the surface with signals consistent with the partial reduction of Cr(VI) to Cr(III) on the aerogel surface. This highlights the relevance of adsorption-based technologies for water remediation, where high-porosity and low-density materials allow for short diffusion pathways and capture electrostatics by protonated amines and redox conversion of hazardous substances. The soft-cure freeze-molding technique is simple, scalable, and compatible with packed-bed/column operation, providing a material platform for tailoring the microstructure (sheets and channels) and surface chemistry to regenerable sorbents for industrial wastewater treatment. Full article