Search Results (15,858)

Given its highly aggressive nature and poor clinical outcome, pancreatic ductal adenocarcinoma (PDAC) requires physiologically relevant in vitro models that more accurately reflect tumor biology and drug response. In this study, adhesive and non-adhesive hydrogel microenvironments were comparatively evaluated for pancreatic cancer spheroid modeling using PANC-1 and MIA PaCa-2 cells. Gelatin methacryloyl (GelMA) hydrogels were synthesized, photocrosslinked, and optimized in terms of stability, swelling, degradation, and cytocompatibility, while 3% agarose was used as a non-adhesive counterpart. Although the optimized GelMA formulation showed adequate structural stability and no cytotoxicity, it did not support spheroid formation. In contrast, agarose enabled the formation of compact, viable, and proliferative spheroids in both cell lines. Agarose-derived spheroids exhibited time-dependent growth, positive Ki-67 staining, and increased HIF-1α expression under 3D conditions, indicating the establishment of hypoxia-associated tumor-like microenvironments. Gemcitabine treatment induced a time-dependent reduction in spheroid viability, while viable cell populations persisted throughout exposure, reflecting the heterogeneous therapeutic response typical of 3D tumor models. Overall, these findings provide a comparative, microenvironment-based assessment of pancreatic cancer spheroid modeling, indicating that hydrogel-dependent differences in adhesivity and structural dynamics are important determinants of spheroid assembly, hypoxia-associated molecular adaptation, and chemotherapeutic response. Overall, these findings provide a comparative, microenvironment-based assessment of pancreatic cancer spheroid modeling, indicating that hydrogel-dependent differences in adhesivity and structural dynamics are important determinants of spheroid assembly, hypoxia-associated molecular adaptation, and chemotherapeutic response. Overall, these findings provide a comparative, microenvironment-based assessment of pancreatic cancer spheroid modeling, indicating that hydrogel-dependent differences in adhesivity and structural dynamics are important determinants of spheroid assembly, hypoxia-associated molecular adaptation, and chemotherapeutic response. Full article

Chemotaxis enables eukaryotic cells to detect and migrate along extracellular chemoattractant gradients spanning several orders of magnitude. This remarkable dynamic range relies on adaptation, a process that allows cells to reset their signaling machinery while preserving sensitivity to incremental changes in stimulus intensity. Although numerous actin-dependent feedback mechanisms have been characterized, the molecular basis of adaptation within an actin-independent core gradient-sensing module remains poorly understood. Here, we identify the Ras GTPase-activating protein, C2GAP1, as a critical F-actin-independent effector of the heterotrimeric G protein, Gα2, in Dictyostelium discoideum. Using cytoskeleton-free gradient-sensing cells, quantitative imaging, biochemical assays, FRET-based G-protein activation measurements, and structural modeling, we demonstrate that C2GAP1 controls concentration-dependent adaptation during gradient sensing. Mechanistically, C2GAP1 directly associates with Gα2 in both GDP- and GTP-bound states, with preferential binding to activated Gα2, thereby sustaining membrane recruitment and locally attenuating Ras and downstream signaling. Loss of C2GAP1 enhances G-protein activation, disrupts local inhibition, and impairs rapid reorientation in dynamic gradients. These findings define a direct coupling between heterotrimeric G proteins and the RasGAP, C2GAP1, as a core adaptive module that enables gradient sensing across a wide concentration range. Full article

Despite major advances in early breast cancer detection and therapeutic strategies, locoregional and distant recurrences, as well as the development of a second primary breast cancer, remain major clinical challenges. Current prognostic tools primarily rely on tumor-specific features, such as the histological grade, hormone receptor status, and proliferative index, and, more recently, on molecular signatures aimed at improving risk stratification and predicting recurrence. However, these approaches remain imperfect, and there is an urgent need to develop complementary strategies. Growing attention has been focused on the tumor microenvironment and the surrounding non-tumoral tissue, which may harbor clinically relevant molecular alterations. Emerging evidence suggests that DNA methylation changes can be detected in the adjacent and contralateral breast tissue and reflect early steps of carcinogenesis or predisposition to tumor development. This phenomenon, often referred to as field cancerization, raises new questions about the dynamics of cancer development. The aim of this work is to provide an integrative overview of DNA methylation alterations in normal breast tissue, including peritumoral and contralateral areas, and to examine their potential as predictive biomarkers of recurrence, based on the available data from tumoral tissue. In theory, these applications seem promising, but their role needs to be confirmed in large prospective trials, in order to overcome barriers to clinical implementation. The currently available evidence does not support a role for DNA methylation in the selection of locoregional and systemic treatment strategies, particularly with a view to reducing the rising number of uni- and bilateral mastectomies performed without any demonstrated survival benefit. Full article

Background/Objectives: SHP2 (PTPN11) is a key regulator of RAS/MAPK signaling and a well-validated target in cancer and developmental disorders. Designing ligands for its catalytic site is challenging due to the pocket’s intrinsic flexibility and the presence of conserved structural water molecules critical for ligand recognition, which limits traditional discovery approaches. This study aimed to systematically identify and prioritize novel SHP2-binding candidates using a computational strategy that accounts for these challenges. Methods: An integrative computational workflow was applied, combining water-aware docking, large-scale virtual screening of 714,409 compounds, MM/GBSA binding free-energy analysis, AI-driven chemical space modeling using ChemBERTa, and microsecond-scale molecular dynamics (MD) simulations. The high-resolution catalytic PTP domain of SHP2 structure was analyzed to identify conserved water molecules (W711, W716, W726, W776) essential for reproducing the crystallographic binding mode of the reference ligand 3LU. Candidates were prioritized based on docking scores, physicochemical criteria, structural inspection, MM/GBSA energetic profiles, and occupancy of distinct chemical space regions. Results: Seven compounds were selected. SwissADME analysis confirmed favorable drug-likeness and GI absorption, with no BBB permeation. ChemBERTa embeddings revealed substantial structural novelty relative to known SHP2 inhibitors. 1 μs molecular dynamics simulations suggested stable binding of compound 4 (2-(3-methyl-2,6-dioxopurin-7-yl)acetate) and persistent interactions with the conserved water network. MM/GBSA evaluation subsequently highlighted its energetically coherent profile. Conclusions: The workflow prioritizes compound 4 as a promising and structurally innovative SHP2-binding candidate. This integrative strategy provides a generalizable approach for targeting proteins with flexible pockets, critical water networks, and limited scaffold diversity, offering a roadmap for challenging computational ligand-prioritization projects. Full article

Sterols and sphingolipids assemble into specialized membrane microdomains that are essential for membrane function, protein sorting, and signal transduction. Although coordinated regulation between sterol and sphingolipid metabolic pathways has long been recognized, the molecular mechanisms mediating this cross-talk remain incompletely defined. Here, we uncover an unanticipated role for the conserved yeast Orm proteins in controlling sterol and neutral lipid homeostasis. Deletion of ORM1 and ORM2 causes hypersensitivity to sterol biosynthesis inhibitors, accumulation of steryl esters, and an increase in lipid droplet number. Consistent with mutants lacking core neutral lipid hydrolases, orm1Δ orm2Δ cells display a marked defect in neutral lipid mobilization. These phenotypes depend on sphingolipid pathway perturbation but cannot be attributed to sphingolipid accumulation alone. Together, these findings position the Orm proteins as regulatory nodes linking sterol metabolism, lipid droplet dynamics, and sphingolipid biosynthesis. Full article

The yak (Bos grunniens), a unique bovine species that is endemic to the Qinghai–Tibet Plateau and adjacent mountainous regions, exhibits remarkable adaptations to chronic high-altitude hypoxia. However, the molecular mechanisms underlying yaks’ adaptation to this extreme environment remain poorly understood. This study aimed to elucidate the spatiotemporal expression dynamics of hypoxia-inducible factor 1α (HIF-1α) and 2α (HIF-2α) in major tissues of yaks across developmental stages (0.5, 1.5, 2.5, and 4.5 years; n = 3 per group). The tissues (heart, liver, spleen, lungs, kidneys, blood vessels and skeletal muscles) were analyzed using hematoxylin and eosin (H&E) staining and immunohistochemistry. The results revealed significant differences in the expression levels of HIF-1α and HIF-2α between tissues and at different ages. In cardiac tissue, both HIF-1α and HIF-2α are localized to the myocardial interstitium, with HIF-1α expression peaking at 1.5–2.5 years and HIF-2α expression reaching its maximum at 2.5 years. Hepatic HIF-1α showed perivenous hepatocytes enrichment and peaked at 2.5 years (p < 0.01 vs. other ages), while HIF-2α was uniformly distributed across lobules without age-related changes. Splenic HIF-1α and HIF-2α levels increased progressively with age, both peaking at 4.5 years (p < 0.01), and age was strongly correlated with expression levels (HIF-1α: r = 0.430; HIF-2α: r = 0.493). In pulmonary tissues, HIF-1α in bronchial smooth muscle peaked at 2.5 years, whereas alveolar septal HIF-2α peaked at 1.5 years (p < 0.05). In the kidney, HIF-1α was primarily localized to tubular epithelial cells and HIF-2α was diffusely distributed in the glomerular interstitium; neither factor showed significant variation across ages. In vascular tissues, HIF-1α expression remained stable across all ages and was predominantly observed in the smooth muscle layer, while HIF-2α exhibited a significant peak in endothelial cells at 2.5 years (p < 0.01). These findings suggest that HIF-1α predominates during early development stages, while HIF-2α becomes dominant as yaks approach maturity. Full article

Background: Menthol is a naturally occurring volatile terpene alcohol, widely used in food, pharmaceutical, and tobacco products; however, its high volatility leads to significant flavor loss during storage and handling. Methods: Herein, bimodal mesoporous silica materials (BMMs) were employed as carriers to encapsulate menthol, the loading and release behaviors were systematically compared using normal-temperature and alcohol-thermal loading methods. Results: Comprehensive characterizations (XRD and SAXS patterns, FT-IR spectra, SEM images, and N₂-sorption isotherms) confirmed that menthol incorporation did not disrupt the hierarchical mesoporous channels of BMMs. The alcohol-thermal loading method achieved a superior menthol loading capacity of 87%, significantly outperforming the normal-temperature loading (58%). Release performances revealed a transition in the dominant release mechanism, from diffusion-controlled behavior at low loading levels to concentration gradient-driven desorption at high loadings. Molecular dynamics simulations further demonstrated that alcohol-thermal loading enabled faster molecular diffusion and a more uniform distribution of menthol within the mesopores due to weaker interfacial interactions, whereas normal-temperature loading induced localized multilayer adsorption, resulting in mesopore blockage and hindered diffusion. In addition, long-term atmospheric release tests assessed sustained menthol retention over 30 days. Conclusions: Overall, this work establishes alcohol-thermal loading as an effective approach for regulating adsorption and release in mesoporous carriers, providing a foundation for developing volatile compound encapsulation strategies. Full article

Conventional wiped-film molecular distillers(WFMDs) often show limited hydrodynamic renewal and mixing when processing high-viscosity materials because of liquid pooling and weak secondary flow. This study investigates a novel grooved scraper design for a wiped-film molecular distiller handling an ethylene glycol/glycerol mixture (42.0 mol% ethylene glycol; density 1196.0 kg/m³; dynamic viscosity 0.222 Pa·s), used here as a representative high-viscosity, heat-sensitive system. Three-dimensional multiphase CFD simulations were performed to examine the combined effects of groove width (2.0–10.0 mm) and scraper tip angle (30–75°) on flow behavior. The results show that a groove width of 7.0 mm increases vorticity gain by 9% and wall shear stress gain by 20% relative to the inline scraper baseline. The grooved geometry generates periodic shear disturbances, promotes radial secondary flow, and strengthens turbulent mixing. A balance between radial mixing enhancement and axial transport continuity is required. Among the tested angles, a tip included angle of 45° produces the highest average vorticity magnitude and more coherent vortex structures. These findings clarify the hydrodynamic regulation mechanism of scraper micro-geometry and support its use as a process-intensification strategy for distiller parameter selection. Full article

The advent of breast cancer molecular subtyping has transformed management, enabling treatment personalisation and de-escalation beyond traditional stage-based approaches. Established biomarkers, such as Ki-67 in luminal disease, HER2 amplification, and PD-L1 expression in triple-negative breast cancer, underpin seminal clinical trials yet remain imperfect predictors of response and long-term outcome. MicroRNAs have emerged as promising next-generation biomarkers and therapeutic tools. As master regulators of gene expression, both tumour-derived and circulating microRNAs can refine diagnosis and molecular subclassification, inform prognosis and therapeutic selection, act as treatment sensitisers, and potentially serve as direct therapeutic targets. Well-characterised miRNAs such as miR-221 have been implicated in endocrine resistance, while recent liquid-biopsy approaches have enabled the identification of circulating miR-145 and exosomal miR-155 as predictors of pathological complete response in HER2-positive disease. Their detectability in tissue, blood and other biofluids offers a minimally invasive means to dynamically monitor cancer behaviour and response, supporting more precise therapeutic decision-making. This review synthesises the current evidence for miRNA-based biomarkers across oestrogen-receptor positive, HER2-positive and triple-negative breast cancer and outlines their potential integration into biomarker-driven clinical trial designs and personalised treatment strategies. Full article

Poly(amidoamine) (PAMAM) dendrimers are widely recognized as versatile nanocarriers due to their tunable architecture and ability to associate with bioactive molecules. In this study, generation 3 PAMAM dendrimers functionalized with triphenylphosphonium (TPP) were employed to investigate the association of structurally related phenolic compounds—caffeic acid, p-coumaric acid, and cinnamic acid—through either covalent conjugation or non-covalent encapsulation. Physicochemical characterization by NMR, dynamic light scattering, and zeta potential measurements revealed the formation of supramolecular aggregates rather than isolated dendrimer units, with hydrodynamic diameters ranging from 127 to 260 nm and positive surface charge across all formulations. Encapsulation efficiencies determined by HPLC reached 93.8% for caffeic acid, 78.9% for p-coumaric acid, and 71% for cinnamic acid, indicating differential association behavior. Molecular dynamics simulations over 1 μs supported these findings, showing stronger and more stable interactions for polar antioxidants, particularly caffeic acid, driven by hydrogen bonding and electrostatic interactions, while cinnamic acid displayed preferential binding in more hydrophobic dendrimer regions. Radical scavenging assays (DPPH• and ABTS•+) demonstrated that all formulations retained antioxidant capacity, although dendrimer association modulated scavenging kinetics. In cellular assays under oxidative stress, free caffeic acid exhibited the strongest immediate reduction of intracellular reactive oxygen species, whereas dendrimer-associated systems showed reduced but significant activity, consistent with decreased solvent accessibility and slower release predicted by simulations. Overall, these results highlight a trade-off between molecular retention and immediate biological efficacy, demonstrating that the mode of association governs antioxidant accessibility and performance. This combined experimental and computational approach provides a mechanistic framework for the rational design of dendrimer-based delivery systems aimed at balancing stability and functional activity. Full article

2,4-Dichlorophenoxyacetic acid (2,4-D) is a vital exogenous auxin for the induction and proliferation of litchi embryogenic callus. At present, its molecular regulation mechanism remains unclear. In this study, transcriptome sequencing samples were selected based on different cell growth phenotypes observed in ‘Feizixiao’ litchi embryogenic callus cultured in liquid medium with or without 2,4-D. By integrating transcriptome profiling with weighted gene co-expression network analysis (WGCNA), we identified key genes and signaling pathways dynamically responsive to 2,4-D concentration changes. We identified 558 commonly differentially expressed genes (DEGs), of which 117 were up-regulated and 387 were down-regulated; functional enrichment analysis revealed significant enrichment in the “plant hormone signal transduction” and “phenylpropanoid biosynthesis” pathways. In the former pathway, genes such as AUX28, GH3.17, GH3.6, and ARR5 were up-regulated; in the latter, by comparison, β-glucosidase 47 and Peroxidase 61 exhibited increased expression levels induced by 2,4-D. Furthermore, among these DEGs, 57 transcription factors belonged to 24 families. Notably, VRN1, FEZ, and DOF5.4 were significantly and rapidly induced by 2,4-D. WGCNA results demonstrated a significant positive correlation between the yellow module and 2,4-D treatment. Small heat shock protein (sHSP) genes constituted the core hub genes in the yellow module. Through Venn analysis of DEGs and key modules, 38 cross-genes were identified, of which non-specific lipid-transfer protein-like genes (nsLTP) were found to be specifically up-regulated without 2,4-D. The transcription factors and genes identified work in synergy to ensure the formation and sustained proliferation of embryogenic callus by precisely regulating the dynamic balance of auxin and cytokinin within cells and maintaining the stability of cell structure. Our findings provide a crucial theoretical foundation for understanding the molecular mechanism of 2,4-D in regulating litchi embryogenic callus proliferation. Full article

Starch–polyphenol complexes have attracted increasing attention as functional ingredients for improving the structural stability and reducing the glycemic potential of starch-based foods, yet their application in extruded fresh noodles remains insufficiently understood. In this study, chestnut starch–resveratrol complexes prepared by heat-moisture synergistic recrystallization treatment (CS-HMRT-Res) were incorporated into extruded fresh noodles, and their quality, structural characteristics, digestibility, and glycemic response were systematically evaluated. Compared with commercial wheat-based Regan noodles, CS-HMRT-Res noodles exhibited enhanced cooking stability (lower swelling and leaching) and improved texture (hardness, chewiness, tensile strength), with a markedly lower total color difference after cooking (ΔE = 1.8 vs. 6.5). SEM, FTIR and XRD indicated a more compact and ordered network; the relative crystallinity of cooked noodles increased to approximately 30.8%. In in vitro digestion, CS-HMRT-Res showed the lowest starch hydrolysis extent at 180 min (45.92%) and yielded a low predicted glycemic index of 53.35, compared with 70.65 for Regan noodles. Consistently, gavage studies in mice confirmed that HMRT-Res-chestnut starch produced the lowest postprandial blood glucose increment response (4.31 mmol/L). Molecular dynamics simulations further suggested that resveratrol could competitively occupy the α-amylase binding cavity and reduce starch accessibility to the enzyme. Overall, CS-HMRT-Res improved processing quality, structural integrity, and reduced glycemic potential, offering a structure-function framework for designing low-GI products. Full article

To investigate the inevitable aging of composite insulators under the coupled effects of electrical, thermal, ice, and fog stresses, as well as to explore their aging mechanisms and residual strength prediction methods, this study collected operational insulator samples from four environmental regions: Tibet, Yunnan, Hunan Xuefeng Mountain, and Anhui/Chongqing. Mechanical properties, including tensile strength, elongation at break, and shear resistance, were tested. The results indicate that the degradation of mechanical performance in composite insulation components can be attributed to the synergistic interaction of operational environments and material characteristics, with the aging behavior of high-temperature vulcanized (HTV) silicone rubber exhibiting significant non-linearity. Based on existing research, molecular dynamics simulations were employed to construct microstructural models at different aging stages, and it was verified that main chain scission, reduced system density, and changes in the elemental chemical environment during aging are closely related to the degradation of material mechanical properties. Based on hyper-elastic constitutive theory and fracture mechanics, a quantitative method for assessing the comprehensive aging degree was proposed, with “service years” and “operational altitude” as the core dimensions. A negative exponential model was established to describe the strength degradation of silicone rubber materials. This model enables the non-destructive estimation of the residual mechanical strength of in-service insulators in complex regions without power interruption, providing a decision-making framework for grid operation and maintenance. Full article

The development of tight heavy-oil reservoirs is severely hampered by the high viscosity and poor mobility of crude oil caused by strong intermolecular stacking interactions among asphaltenes, coupled with the substantial adsorption loss and inadequate deep transport capacity of conventional displacement agents. By targeted penetrant delivery, a novel nanoemulsion system with a well-defined “core–shell” architecture was synthesized to address these critical challenges. The physicochemical properties, stability and oil displacement performance were evaluated. The prepared nanoemulsion exhibited an ultrasmall and uniform particle size distribution between 10 nm and 20 nm. It also demonstrated exceptional dispersibility in aqueous media and remarkable thermal and salinity stability under reservoir conditions. Furthermore, an ultralow critical micelle concentration of approximately 0.01% could be achieved and the oil–water interfacial tension was reduced to 7.3 × 10⁻² mN/m, significantly outperforming the conventional surfactant AES. Core flooding tests revealed that the proposed nanoemulsion enhanced oil recovery by 37.1% and attained a displacement efficiency of 68.9% in oil-wet capillary models. Molecular dynamics simulations further elucidated the underlying synergistic mechanism. The hydrophilic shell minimized adsorption on rock surfaces, facilitating deep migration within nanoporous channels. The hydrophobic core, containing terpinene as a penetrant, effectively disrupted the π-π stacking of asphaltenes due to its nonplanar molecular configuration. This disruption transformed the asphaltene aggregates from a tightly packed state to a dispersed state, resulting in substantial viscosity reduction. This work elucidated the mechanism of asphaltene aggregate disruption by nanoemulsions at the molecular level, offering a promising and theoretically grounded strategy for the efficient exploitation of tight heavy-oil reservoirs. Full article

Laser assistance offers a promising pathway for high-efficiency and low-damage ultraprecision grinding for difficult-to-machine hard-brittle semiconductors. This study employs atomistic simulation to investigate the surface removal and subsurface damage mechanisms of C-, M-, and A-plane AlN workpieces during single-grit laser-assisted nanogrinding (LAG). The results indicate that LAG reduces material pileup, thereby decreasing the grit–workpiece contact area and grinding resistance. By leveraging laser-induced thermal effects to enhance atomic plastic flow, LAG evidently achieves a higher material removal rate than conventional grinding (CG). Grinding the C-plane along a <11–20> orientation yields the lowest surface roughness, although this improvement is not useful for the M- and A-planes. Tangential force increases linearly with grinding depth in both methods, but LAG exhibits a lower rate of increase. LAG consistently produces lower grinding forces and friction coefficients and results in lower dislocation densities in C- and A-plane AlN workpieces at nearly all grinding depths. The C-plane exhibits the thinnest damage layer, followed by the M-plane, with the A-plane the thickest. Increasing the laser power density lowers the grinding force and enhances the removal efficiency. Optimal power density minimizes subsurface damage and improves surface quality; however, excessive power density exacerbates damage. This work provides valuable insights for developing high-efficiency, low-damage LAG techniques for hard-brittle semiconductors. Full article