Search Results (241,877)

This study investigates the atmospheric and upper-ocean responses associated with Super Typhoon (TY) Lekima (2019) during 4–12 August, including its landfall over Zhejiang Province, China. Variations in sea surface temperature (SST), latent heat flux (LHF), water vapor flux (WVF), total column water vapor (TCWV), vertical integral moisture divergence (VIMD), mean sea level pressure (MSLP), wind circulation, precipitation, subsurface temperature and salinity, and Ekman pumping velocity (W_E) were analyzed throughout the typhoon life cycle. Before intensification, SSTs of 29.5–31.0 °C indicated favorable ocean-surface conditions. During and after the storm passage, SST decreased to approximately 26.0–27.5 °C along portions of the track and below 25.0 °C near the Zhejiang coast, with stronger cooling on the right-hand side of the track. Surface salinity decreased by approximately 0.3–0.8 PSU during 8–10 August, with freshening extending through the upper 30–40 m. The Ekman pumping field identified regions where wind-stress curl favored upwelling and downwelling, with stronger positive signals occurring on the right side of the track. During the active maritime stage, LHF values of approximately −300 to −200 W m⁻² indicated enhanced upward latent heat transfer. WVF reached 1800–2200 kg m⁻¹ s⁻¹, TCWV exceeded 70 kg m⁻², and VIMD decreased below approximately −100 × 10⁻⁵ kg m⁻² s⁻¹, indicating enhanced moisture transport and convergence. These conditions coincided with daily precipitation exceeding 120 mm and locally reaching approximately 160 mm over northern and northwestern coastal Zhejiang. The minimum daily mean MSLP decreased from 1000 to 972–976 hPa during peak intensity and subsequently increased as Lekima approached landfall and weakened inland. While these responses are qualitatively consistent with previous TY case studies, our study provides new quantitative benchmarks and process attribution through heat budget analysis. This integrated, stage-based analysis provides a comprehensive quantitative reference for model validation and future comparative studies of landfalling typhoons in the western North Pacific. Full article

Cold stress (CS) severely limits the growth and productivity of rice (Oryza sativa L.), particularly in temperate regions where abrupt temperature declines frequently occur during early developmental stages. In recent years, nanoparticle (NP) application has emerged as a promising approach for alleviating CS; however, systematic comparisons of different NPs across multiple growth stages remain unclear. This study evaluated the effectiveness and physiological mechanisms of four NPs (Fe₂O₃, ZnO, TiO₂, and CeO₂) in enhancing CS tolerance of rice seedlings using four cultivars with contrasting cold tolerance: two conventional cultivars (ZJZ-17, cold-sensitive; XZX-6, cold-tolerant) and two hybrid cultivars (LLY-7108, cold-tolerant; LLY-32, cold-sensitive). Seedlings were subjected to CS (14 °C day/10 °C night) for 5 days at three developmental stages (14, 21, and 28 days after emergence), followed by a 7-day recovery period under optimal conditions. CS markedly reduced plant height (34.8%), fresh weight (57.2%), dry weight (50.0%), and chlorophyll a and b contents (48%) following recovery. Foliar application of NPs significantly mitigated the adverse effects of CS, with Fe₂O₃ and ZnO showing the highest effectiveness. Fe₂O₃ treatment increased plant height, fresh weight, and dry weight by 25.6%, 43.5%, and 40.6%, respectively, relative to cold-stressed plants, while chlorophyll a and b contents increased by 41.6% and 42.2%. NPs application alleviated oxidative damage by reducing reactive oxygen species (up to 67.4%), malondialdehyde (up to 51.2%), and proline accumulation (up to 60.4%). Enhanced antioxidant defense was evidenced by increased activities of superoxide dismutase (66.6%), peroxidase (59.6%), and catalase (34.3%) under Fe₂O₃ treatment. Yield-related traits also showed significant recovery, with Fe₂O₃ increasing tiller number, spikelets per panicle, and grain yield per plant. The hybrid cultivar LLY-7108 consistently exhibited greater CS tolerance than conventional cultivars, while the cold-sensitive cultivar ZJZ-17 showed the greatest susceptibility. CS imposed at later growth stages (28-day-old seedlings) caused less damage and allowed greater recovery than early-stage stress (14-day-old seedlings). Overall, NP-mediated enhancement of photosynthesis and antioxidant capacity significantly improves CS tolerance and yield performance in rice, with Fe₂O₃ NPs emerging as a promising strategy for mitigating CS. These findings provide practical insights for rice cultivation in regions prone to chilling events and contribute to the development of nanoparticle-based approaches for rice production under climate stress. Full article

Chronic hepatitis C virus (HCV) infection is an established risk factor for B-cell lymphoproliferative disorders and represents a paradigmatic model of infection-driven lymphomagenesis. Although direct-acting antivirals have markedly reduced the burden of HCV-related disease, HCV-associated lymphomas continue to occur. Moreover, HCV screening remains incomplete in some geographical areas and healthcare settings, leaving a substantial proportion of infected individuals unaware of their status. This narrative review integrates current evidence on the mechanisms linking chronic HCV infection to mixed cryoglobulinemia and overt B-cell non-Hodgkin lymphoma. HCV lymphotropism and persistent antigenic stimulation could initially promote the selection and expansion of autoreactive B-cell clones, while mixed cryoglobulinemia represents the most informative pre-lymphomatous risk condition. Cytokine-mediated survival signals, particularly those involving B-cell activating factor, reinforce clonal persistence and cooperate with host genetic susceptibility, impaired apoptotic control, and activation-induced cytidine deaminase-mediated genomic instability. The progressive acquisition of somatic driver mutations, copy-number alterations, and epigenetic and transcriptomic changes may enable selected clones to escape functional anergy and become increasingly independent of the original viral stimulus that, in turn, represents an initial trigger of the lymphoproliferative process. Recurrent abnormalities converge on NF-κB, NOTCH, chromatin-regulatory, apoptotic, and cell-cycle pathways, although HCV-associated lymphomas remain molecularly heterogeneous. Emerging microRNA profiles further contribute to the molecular characterization of the transition from chronic infection and cryoglobulinemia to lymphoma. Despite the availability of highly effective antiviral therapies, HCV-associated lymphomagenesis remains clinically relevant and continues to provide an especially informative model for understanding how chronic viral infection can drive human cancer development. Full article

As power densities in Wide Band Gap (WBG) semiconductors increase, traditional steady-state cooling methods often fail to address the rapid thermal transients. This paper investigates a diversity of cooling architectures for discrete Silicon Carbide (SiC) MOSFETs, and a frequency-dependent thermal characterization of different cooling technologies. This paper also presents a new measurement method of heat transfer through multilayer systems, which determines the thermal diffusivity of the power device in real dynamic operation. The measurement of the stored energy in the active component using temperature sensors proves itself to be a practical, rapid, low-cost, and non-invasive method. The results show that the active Peltier stage significantly allows for more frequent current bursts before reaching the thermal limit, thereby proving the system’s capability in high-frequency transient applications to be thermally stable. The analysis of different power systems with different types of cooling, for a range of frequencies of the drive signal for SiC MOSFETs, enables power electronic engineers to evaluate the efficacy of the cooling systems related to the operating frequency and not only as a function of the dissipated power. Analysis of thermal faults in MOSFETs with SEM/EDS methods reveals the weak points in the design of these WBG devices. Full article

The interface failure modes between fibers and asphalt mastic exhibit complex and diverse morphologies under the influence of multiple factors, making cluster analysis difficult. To address this issue, this study proposes an improved growth curve mixture model (IGCMM) for the unsupervised clustering of interface failure modes. Through single-fiber pull-out tests on 90 specimens under three temperatures (−10 °C, 25 °C, and 60 °C) and three fiber types (basalt, glass, and polyester), load–displacement curves were obtained. The multivariate power exponential (MPE) distribution was used to characterize the peak and heavy-tailed features of residuals. Due to the high dimensionality caused by the joint analysis of multiple datasets, principal component analysis (PCA) was employed to compress the 200-dimensional curve data into three principal components, with all model parameters estimated in the low-dimensional space. The Expectation–Maximization (EM) algorithm combined with the extended Bayesian Information Criterion (eBIC) determined the optimal eight failure mode clusters. The results exhibit a high posterior assignment confidence: 96.7% of samples had posterior probabilities exceeding 0.999. The eight statistical patterns were successfully mapped to four theoretical failure modes—fiber pull-out, medium-temperature matrix failure, high-temperature matrix failure, and mixed failure—revealing the coupled regulatory mechanism of temperature and fiber type on interface failure. The framework established in this study—“data-driven clustering–physical parameter anchoring–failure mechanism interpretation”—provides new theoretical tools and methodological support for the mesoscale interface failure diagnosis and crack resistance optimization design of fiber-reinforced asphalt pavement materials. Full article

Background/Objectives: Human physiological evidence for functional clothing is limited, and garment changes may reflect ordinary material or measurement effects. We described surface-temperature and heart rate variability (HRV) observations before and after wearing black-silica-containing clothing and quantified paired changes and between-participant dispersion. Methods: Ten adults enrolled as healthy volunteers completed this single-center, non-randomized, unblinded, uncontrolled, fixed-order, single-group before–after pilot protocol. No physically matched control textile was used. No directional hypothesis or single primary outcome was prospectively specified. Exploratory domains comprised abdominal and leg surface temperature and eight RR interval (RRI)-derived HRV indices. All participants were analyzed; a post hoc n = 9 quality-control sensitivity analysis excluded one participant with a short post-wearing RRI segment. Effect estimates, 95% confidence intervals (CIs), and Holm-adjusted p values were reported. Between-participant dispersion was secondary and exploratory. Results: Leg surface temperature showed a modest increase of 0.668 °C (95% CI −0.001 to 1.336; raw p = 0.050; Holm p = 0.100); abdominal temperature changed by 0.007 °C (95% CI −0.447 to 0.462). No paired HRV outcome retained support after correction (all Holm p ≥ 0.797). In the secondary dispersion analysis, total power had an after/before log-scale SD ratio of 0.612 (bootstrap 95% CI 0.347 to 0.861; Holm p = 0.031); no dispersion outcome retained support in the n = 9 sensitivity analysis. Conclusions: This small uncontrolled pilot provides hypothesis-generating observations but cannot isolate an effect attributable specifically to black silica or demonstrate autonomic benefit, therapeutic action, or product efficacy. Confirmation requires an adequately powered, randomized, participant-blinded crossover study using physically matched garments and standardized measurement conditions. Full article

In the current manuscript, the hot deformation behavior and the thermal processing map of 6082-T6 rolled aluminum alloy sheet were studied. A series of compression tests were conducted using the Gleeble-3500 thermal simulation machine under the conditions of 200–350 °C and 0.001–1 s⁻¹. In order to tackle the stress errors caused by friction and plastic deformation temperature rise, the friction correction model and the adiabatic temperature rise interpolation method were used, respectively, to correct the flow stress curve. Based on the corrected data, a strain-compensated Arrhenius constitutive equation was constructed. Through the 4th-order polynomial fitting of material parameters and strain, the measured and predicted stresses were compared, with the average relative error reaching 10.50%. The thermal processing map was drawn based on the dynamic material model, and the material instability region was concentrated in the low-temperature high-strain rate zone. Within the investigated temperature and strain rate range, the optimal processing window was 320–350 °C and 0.001–0.031 s⁻¹. Combined with microscopic characterization by Optical microscope and transmission electron microscope, it was found that deformation at low temperature and high strain rate was mainly dynamic recovery, and dynamic recrystallization could fully occur at high-temperature low-strain rate. The research results can provide theoretical support for the optimization of the hot forging and hot stamping processes of this alloy. Full article

Basalt fibre-reinforced polymer (BFRP) dowel bars offer a corrosion-resistant alternative to steel dowels for jointed concrete infrastructure, particularly in aggressive marine environments. However, the durability of full-scale BFRP dowels remains insufficiently understood because their shear-dominated behavior differs from that of conventional small-diameter FRP reinforcement. This study investigates the durability of 25-mm epoxy-based BFRP dowel bars exposed separately to artificial seawater and alkaline solution at 60 °C under accelerated continuous-immersion conditions. Mechanical performance was evaluated through flexural strength, transverse shear strength, and interlaminar shear strength (ILSS), while chemical and microstructural changes were examined using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM/EDS). At the common 2- and 4-week exposure durations, seawater caused greater flexural-strength losses (10.0% and 11.5%) than alkaline exposure (1.3% and 8.5%), whereas alkaline exposure caused greater reductions in transverse shear strength (7.3% and 8.3% vs. 2.5% and 5.5%) and ILSS (7.0% and 10.0% vs. 1.3% and 2.4%). FTIR and SEM/EDS observations provided complementary evidence of matrix modification and fibre–matrix interfacial deterioration. Overall, the investigated BFRP dowel system showed limited mechanical degradation under the accelerated conditions, indicating promising material-level durability performance within the investigated exposure durations. Full article

Liquid-state ¹³C–¹³C 2D INADEQUATE NMR spectroscopy provides unparalleled direct carbon–carbon connectivity mapping via scalar couplings, delivering unambiguous structural evidence that conventional HSQC and HMBC methods cannot, particularly for quaternary carbons, fully substituted aromatics, and overlapping polymer resonances. Despite sensitivity challenges arising from low ¹³C natural abundance (~1.1%), this review examines the technique’s evolution from its 1981 introduction to contemporary innovations, compiling over 100 application entries across natural products, synthetic molecules, mixtures, fullerenes, metabolomics, oligomers and polymers. Significant methodological advancements—including cryogenic probe technology (up to 5.5-fold sensitivity gain), J-compensated sequences, composite refocusing (INADEQUATE CR), hybrid INEPT-INADEQUATE approaches, adiabatic pulses, and Overhauser DNP-INADEQUATE—are critically assessed alongside computerized analysis algorithms (CCBond, FRED) and network-based metabolomics tools (INETA, PyINETA). Practical guidance covering optimal J_CC coupling selection, relaxation management, and a decision tree for experiment selection is consolidated. Looking forward, the convergence of artificial intelligence, non-uniform sampling, and integration with density functional theory promises to transform 2D INADEQUATE from a specialist technique of last resort into a routinely accessible tool for structural elucidation. Full article

Accurate prediction of concrete mechanical and deformation behavior remains one of the major challenges in materials engineering and science. This study presents results from structural and finite element (FE) modeling, providing a prediction of the stress–strain state of hardened cement paste and concrete. It proposes a two-step method: first, develop an FE model for hardened cement paste from the monofractional structural model; second, develop an FE model for concrete by integrating deformation characteristics derived from the hardened cement paste model and interfacial transition zone (ITZ) parameters, calculated by the authors’ method. This study involved: designing structural models of hardened cement paste and concrete, constructing FE models based on these structures, and validating them by comparison with experimental data. The simulations used monodisperse structural and tetrahedral hinge–rod finite element models. The novelty of the method is the combination of simplified monofractional structural models and ITZ volume calculation using parameters for structural density and relative sizes of elements, which allows for the design of an FE model of concrete integrated with an FE model of hardened cement paste. The results confirm the high accuracy of the developed models for each concrete class in the range from C16/20 to C55/67, with deformation deviations not exceeding 6% and strength deviations not exceeding 10%. The authors’ principles of FE modeling for hardened cement paste and concrete were established. Full article

In the present study, we employed qualitative and quantitative content analytic methods to explore how fans use social chatbots to engage with the object of their fandom. Drawing on theories of self-disclosure, the Computers Are Social Actors (CASA) paradigm, and parasocial relationships, we investigated motivations underlying chatbot use among fandom communities. Data consisted of 813 Reddit comments discussing Character.ai use. Using qualitative thematic analysis, n-gram collocation analysis, and dictionary-based text analysis, the study identified five primary motivations: fan facilitation, safe harbor, virtual social compensation, real-life (IRL) social contact, and entertainment. Findings indicated that Character.ai was used by fans to extend fandom experiences, engage in role-play and creative storytelling, seek emotional support, compensate for unmet social needs, and explore interests in a judgment-free environment. Evidence from the thematic and n-gram analyses suggested that fandom engagement and social motivations were identified by users as important drivers of use, while utilitarian functions also played a role. The findings highlight how social chatbots may be reshaping fan practices, parasocial engagement, and digitally mediated companionship. Findings are discussed in terms of the dual character of fan C.ai use, namely as a tool to both meet social needs and avoid social contact, with its potential benefits and hazards for fans engaging with social chatbots. Full article

Regional metamorphic graphite deposits in the North China Craton (NCC) are important crystalline graphite resources, but the links among sedimentary protolith, metamorphic evolution, and graphite mineralization remain insufficiently constrained in many ore belts. In the Datong–Xinrong graphite belt of northern Shanxi Province, the studied ore is hosted by graphite-bearing gneiss of the Paleoproterozoic Huangtuyao Formation. The graphite-bearing rocks are interpreted as mudstone-derived paragneiss and contain graphite, plagioclase, quartz, biotite, diopside, garnet, alkali feldspar, pyrrhotite, and minor sillimanite. To clarify the ore-controlling factors and metallogenic evolution of these rocks, we integrated whole-rock geochemistry, Raman spectroscopy of carbonaceous material (CM), and zircon U-Pb geochronology. Geochemical indicators and discrimination diagrams show that the protolith was deposited in a continental-margin setting under dry, brackish-water, and generally oxygen-rich conditions. Raman CM thermometry yields peak metamorphic temperatures of 445.9–534.0 °C, and mineral assemblage constraints indicate pressures of 6.10–7.13 kbar. Zircon U-Pb ages constrain the maximum depositional age of the sedimentary protolith to 2102 ± 42 Ma and the age of mineralization-related metamorphism to 1888 ± 25 Ma. These results support a sedimentary–metamorphic model in which carbon-bearing mudstone was deposited along an early Paleoproterozoic continental margin and was later transformed into graphite-bearing gneiss during late Paleoproterozoic orogenic metamorphism. Full article

This paper compares the financial determinants of firm growth in cases of severe versus tolerable information asymmetry. The paper also compares the observed and stochastic (uncertain) information asymmetry. The data include the nonfinancial firms listed on the NASDAQ100 and DJIA30 for the quarterly period of 1992Q2–2023Q3. The robust results show that (a) firms manage observed and expected (stochastic) severe information asymmetry by focusing on the productivity of fixed assets; (b) the severity of information asymmetry leads firms to reduce debt financing (both short- and long-term) as well as the retention ratio in attempts to decrease the severity of information; (c) the measurement of firm growth using sales-weighted fixed assets growth distinguishes severe and tolerable information asymmetry, which is not realized when the Tobin Q ratio is used; (d) severe and tolerable information asymmetry are systematic factors that affect all firms apart from changes in size; and (e) economic policy uncertainty affects firm growth in addition to the severity of information asymmetry. This paper contributes to the related literature in terms of treating asymmetric information stochastically, as stock prices usually exhibit stochastic patterns. In addition, the results offer insights for both firm management and policy makers regarding the significant financial and macroeconomic factors that can be utilized for managing firm growth in cases of uncertain severe and tolerable information asymmetry. Full article

New prenylated isoindolinone alkaloids, aspernidines C-E (1–3), a new diketopiperazine alkaloid, protubonine C (4), and new polyketides, (±)-asperisocoumarin J and asperisocoumarin K (5 and 6), were isolated from the mangrove-derived fungus Aspergillus sp. SCSIO 41440, together with six known compounds (7–12). Comprehensive NMR and mass spectrometric analysis, single-crystal X-ray diffraction, and calculated electronic circular dichroism (ECD) were employed for the structural elucidation and stereochemical assignment of these compounds. All compounds were evaluated for their acetylcholinesterase (AChE) inhibitory activity. Compound 10 exhibited potent AChE inhibition with an IC₅₀ value of 3.16 ± 1.16 μM. Molecular docking analysis further revealed that 10 binds strongly to the AChE active site (PDB: 4EY7). These findings suggest that compound 10 represents a candidate scaffold for further investigation as an AChE inhibitor. Full article

Desulfurization ash (DA) is a kind of industrial solid waste generated during flue gas desulfurization. To overcome the limited utilization of reactive calcium-bearing constituents and the insufficient mineralogical stability of DA, this study proposes a thermal CO₂ modification approach based on the synergistic coupling of oxidation and carbonation, and systematically investigates the associated evolution of mineral phases and microstructural features. The effects of reaction temperature, CO₂ flow rate, and reaction time are evaluated using TG-DSC, XRD, FT-IR, SEM-EDS, particle size analysis, and carbon-sulfur analysis to elucidate the reaction behavior of DA under a CO₂ atmosphere. The results demonstrate that reaction temperature is the dominant factor governing the modification process. During heating, CaSO₃ is preferentially oxidized to CaSO₄ under the CO₂ atmosphere, thereby stabilizing the sulfur-bearing components. Subsequently, Ca(OH)₂ undergoes carbonation to form CaCO₃, simultaneously contributing to CO₂ sequestration. Under the optimized conditions of 450 °C, a CO₂ flow rate of 120 mL/min, and a reaction time of 60 min, the resulting CaCO₃ exhibits a pronounced needle-like CaCO₃ morphology, while the CO₂ uptake reaches a maximum of 16.71%. These findings clarify the coupled oxidation–carbonation mechanism and mineral transformation behavior of DA during thermal CO₂ modification, providing a theoretical basis and technical reference for the low-carbon utilization of industrial solid wastes. Full article