ARTICLE | doi:10.20944/preprints202307.1453.v1
Subject: Chemistry And Materials Science, Metals, Alloys And Metallurgy Keywords: Laser welding; Al-Si coated hot stamping steel; Galvanized steel; Microstructure; Mechanical properties; Ni foil
Online: 21 July 2023 (09:05:35 CEST)
To weaken the harm of Al-Si coating and increase the strength of welded joint, variable thickness of Ni foil (Ni, an austenitic formation element) was added into the lap laser welding Al-Si coated 22MnB5 hot stamping steel/galvanized steel joints. The joints' weld appearance, microstructure, and mechanical properties were explored. The weld altered from X-shape to Y-shape with the increased thickness of Ni foil. During welding, Al-Si coating was melted and diluted into the welding pool, forming δ-ferrite (a rich-Al phase with low toughness and strength) in FZ and FB. This phase deteriorated the strength of the joints. After adding Ni, the amount and size of the δ-ferrite phase decreased. With a significant thickness of Ni foil, δ-ferrite would disappear. However, a new phase (FM, rich-Ni phase) probably formed except PM(a no or negligible Ni phase). The heat-affected zone (HAZ) on the side of 22MnB5 comprised a coarse martensite zone, refined martensite zone, martensite+ferrite zone, and tempered martensite zone from the FZ to the basic material. HAZ on the side of galvanized steel mainly contained ferrite and pearlite. After adding Ni foil, the strength of the joint was more than that without Ni. The maximum strength of the joint can be up to 679MPa because of the disappearance of δ-ferrite. Meanwhile, the toughness of the joint increased. The fracture mode was from three mixed fractures(cleavage, quasi-cleavage, and dimple) to one fracture(dimple).
Subject: Chemistry And Materials Science, Biomaterials Keywords: bismuth selenide nanoparticles; photothermal killing; apoptosis; autophagy; stress-related signaling pathway
Online: 10 May 2021 (10:52:30 CEST)
With a highly efficient optical absorption capability, bismuth selenide (Bi2Se3) nanomaterial can be used as an outstanding photothermal agent for anti-tumor treatment and shows promise in the field of nanotechnology-based biomedicine. However, little research has been done on the relevant mechanism underlying the photothermal killing effect of Bi2Se3 nanomaterial. Herein, the photothermal effects of Bi2Se3 nanoparticles on A549 cells were explored with emphasis put on autophagy. Firstly, we characterized the structure and physicochemical property of the synthesized Bi2Se3 and confirmed their excellent photothermal conversion efficiency (35.72%), photostability, biocompatibility and ability of photothermal killing on A549 cells. Enhanced autophagy was detected in Bi2Se3-exposed cells under an 808 nm laser. Consistently, an elevated expression ratio of LC3-II to LC3-I, a marker of autophagy occurrence, was induced in Bi2Se3-exposed cells upon NIR irradiation. Meanwhile, the expression of cleaved-PARP was increased in the irradiated cells dependently on the exposure concentrations of Bi2Se3 nanoparticles. Pharmacological inhibition of autophagy by 3-methyladenine (3-MA) further strengthened the photothermal killing effect of Bi2Se3. Meanwhile, stress-related signaling pathways including p38 and SAPK/JNK were activated coupled with the attenuated PI3K/Akt signaling. Our study figures out that autophagy and the activation of stress-related signaling pathways were involved in the photothermal killing of cancerous cells by Bi2Se3, which provides a more understanding of photothermal nanomaterials.
ARTICLE | doi:10.20944/preprints202310.0315.v1
Subject: Public Health And Healthcare, Primary Health Care Keywords: Protein energy supply ratio; Overweight/obesity; Children; Adolescents; NHANES
Online: 6 October 2023 (05:47:43 CEST)
Background: The proportion of dietary protein may play a key role in the development of obesity in children and adolescents. Methods: Cross-sectional data of 4,336 children and adolescents from the National Health and Nutrition Survey (NHANES) during 2011 to March 2020 were analyzed. Multivariate logistic regression analysis was used to estimate odds ratios (OR) and 95% confidence intervals, and restriction cubic spline was uesd to explore nonlinear relationships of dietary protein energy supply ratio and obesity in children and adolescents. Results:In the adjusted logistic regression model, for every 1% increase in dietary protein energy ratio in children and adolescents, the increased risk of obesity was 4% (OR=1.04,95%CI:1.01-1.08). The restrictive cubic spline showed a nonlinear relationship between dietary protein energy ratio and obesity in children aged 6-11 years (P <0.05). The dietary protein energy supply ratio was included in the logistic regression model after converting to quartiles into categorical variables. The adjusted OR of children aged 6-11 years was 2.08 (95%CI:1.34, 3.23,P <0.01) for the highest quartile of dietary protein energy supply ratio compared with the lowest quartile. Conclusion: In American children, dietary protein energy supply ratios was positively correlated with obesity, independent of individual characteristics and energy.
ARTICLE | doi:10.20944/preprints202310.0015.v1
Subject: Environmental And Earth Sciences, Ecology Keywords: coastal wetland; carbon; nitrogen; coupling; stoichiometry; meta-ecosystem
Online: 1 October 2023 (08:52:35 CEST)
The dynamics of hydrological lateral nutrient fluxes contribute to our understanding of ecological functions related to energy, materials, and organism flows across various spatiotemporal scales. To explore the connectivity between multiple spatial flow processes, we conducted a one-year field measurement to assess lateral hydrologic carbon (C) and nitrogen (N) fluxes over the continental shelf in the Yangtze estuary. We observed a significant correlation between the differences in remote sensing-based estimates of gross primary production (GPP) (∆GPPMODIS) and the differences in eddy covariance (EC) tower-based GPP (∆GPPEC) at both high-elevation and low-elevation sites. Over the course of a year, our predicted daily maximum tidal elevation (TE) closely matched the observed values in the creek, which facilitated the development of theoretical models to simulate biogeochemical cycling processes and aquatic ecosystem functions. Our findings indicate that the studied saltmarsh acts as a net exporter of dissolved total C (DTC) while serving as a net sink for dissolved total N (DTN). Furthermore, there is a significant correlation in the total dissolved stoichiometry of the C/N ratio between imports and exports. These findings highlight the importance of integrating ecological stoichiometric principles to gain a deeper understanding of the complex relationships between physical, chemical, and biological processes, particularly within the context of the meta-ecosystem framework. Additionally, when considering reciprocal hydrological lateral C and N flows, single ecosystem can function both as sources and sinks within the meta-ecosystem framework.