ARTICLE | doi:10.20944/preprints201805.0052.v1
Subject: Chemistry And Materials Science, Polymers And Plastics Keywords: immiscible blend; compatibilization; homogeneous phase; alcoholysis; carbonyl group; copolymers
Online: 3 May 2018 (07:57:59 CEST)
An immiscible blend of poly(hydroxy ether of bisphenol-A) (phenoxy) and poly(1,4-butylene terephthalate) (PBT) with phase separation was observed in as-blended samples. However, compatibilization of the phenoxy/PBT blends can be promoted through chemical exchange reactions of phenoxy with PBT upon annealing. In contrast to the as-blended samples, the annealed phenoxy/PBT blends had a homogeneous phase with a single Tg that could be enhanced by annealing at 260°C. Infrared (IR) spectroscopy demonstrated that phase homogenization could be promoted by annealing of the phenoxy/PBT blend, where alcoholytic exchange occurred between the dangling hydroxyl group in phenoxy and the carbonyl group in PBT in the heated blends. The alcoholysis reaction changes the aromatic linkages to aliphatic linkages in carbonyl groups, which initially led to the formation of a graft copolymer of phenoxy and PBT with an aliphatic/aliphatic carbonyl link. The progressive alcoholysis reaction resulted in the transformation of the initial homopolymers into block copolymers and finally into random copolymers, which promoted phase compatibilization in blends of phenoxy with PBT. Due to the fact that the amount of copolymers increased upon annealing, crystallization of PBT was inhibited by alcoholytic exchange in the blends.
ARTICLE | doi:10.20944/preprints202207.0060.v1
Subject: Physical Sciences, Optics And Photonics Keywords: perfect absorber; ultra-broadband; visible region; near infrared region
Online: 5 July 2022 (05:15:18 CEST)
As solar energy is a low-cost and clean energy source, there has been a great deal of interest in how to harvest it. To absorb solar energy efficiently, we have designed a broadband metamaterial absorber based on the principle of Fabry–Pérot (FP) cavity and surface plasmon resonances (SPRs). We propose a broadband perfect absorber consisting of a four-layer structure of silica-tungsten-silica-titanium (SiO2-W-SiO2-Ti) for the incident light wavelength range of 300–2500 nm. The structure achieves perfect absorption of incident light in the wavelength range of 351.8–2465.0 nm (absorption >90%), with an average absorption of 96.3%. The advantage of our proposed structure is that it combines the characteristics of both high and broadband absorption and has a high overall absorption efficiency for solar radiation. It is also independent of polarization and insensitive to incident angle. We investigated how absorption was affected by different structures, materials, geometrical parameters, and refractive indices for different dielectric materials, and we explored the reasons for high absorption. This structure is refractory and ultra-thin, and it offers a good trade-off between bandwidth and absorption. It therefore has premium application prospects and value.
ARTICLE | doi:10.20944/preprints201807.0480.v1
Subject: Chemistry And Materials Science, Nanotechnology Keywords: surface plasmon resonance; core–shell nanoparticles; discrete-dipole approximation; aspect ratio
Online: 25 July 2018 (11:53:51 CEST)
In this work, numerical simulations for the absorption and scattering efficiencies of spheroid core–shell nanoparticles (CSNs) were conducted and studied using the discrete-dipole approximation method. The characteristics of surface plasmon resonances (SPR) depend upon shell thickness, the compositions of the core and shell materials, and the aspect ratio of the constructed CSNs. We used different core@shell compositions, specifically Au@SiO2, Ag@SiO2, Au@TiO2, Ag@TiO2, Au@Ag, and Ag@Au, for extinction spectra analysis. We also investigated coupled resonance mode wavelengths by adjusting the composition’s layer thickness and aspect ratio. In this study, we show that the extinction efficiency of the Ag@TiO2 core–shell nanoparticles (CSNPs) was higher than that of the others, and we examined the impact of TiO2 shell thickness and Ag core radius on SPR peak positions. From the extinction spectra we found that the Ag@TiO2 nanoparticle had better refractive index sensitivity and figure of merit when the aspect ratio was set to 0.3. All of the experimental results proved that the tunability of these plasmonic resonances was highly dependent on the material used, the layer thickness, and the aspect ratio of the core@shell CSNPs.
ARTICLE | doi:10.20944/preprints202301.0370.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: Chinese chestnut; replaceable bud; programmed cell death; transcriptomics
Online: 20 January 2023 (06:31:11 CET)
Previous research suggests that the senescence and death of the replaceable bud in chestnut cultivar (cv.) ‘Tima Zhenzhu’ involves programmed cell death (PCD). However, the molecular network responsible for regulating replaceable bud PCD is poorly characterized. Here, we performed transcriptomic profiling of the chestnut cv. ‘Tima Zhenzhu’ replaceable bud before (S20), during (S25), and after PCD (S30) to ascertain the molecular mechanism underlying the PCD process. A total of 5,779, 9,867, and 2,674 differentially expressed genes (DEGs) were discovered upon comparison of S20 vs. S25, S20 vs. S30, and S25 vs. S30, respectively. Approximately 6,137 DEGs common to at least two comparisons were selected for GO and KEGG enrichment analyses to interrogate the main corresponding biological functions and pathways. GO analysis showed that these common DEGs could be divided into three functional categories, including 15 cellular components, 14 molecular functions, and 19 biological processes. KEGG analysis found that “plant hormone signal transduction” included 93 DEGs. Overall, 441 DEGs were identified as related to the process of PCD. Most of these were found to be genes associated with ethylene signaling, as well as initiation and execution of various PCD processes. A hypothetical model, consisting of three overlapping processes, is proposed for the replaceable bud PCD: First, ethylene signaling is activated during preparation for PCD, in order to regulate the activity of downstream targets. Next, during PCD initiation, the up-regulation of several TFs (including MYB, MADS-box, bHLH, and NAC TFs) induces an increase in cytochrome c expression and in the cytosolic Ca2+ content, activating the Ca2+-dependent signaling cascade. Finally, during PCD execution, the process of autophagy and the activity of proteases (i.e., cysteine proteinases RD21A-like, metacaspase-9-like, vacuolar-processing enzyme-like, and senescence-associated proteins for hydrolysis) work synergistically to clear the cell of cellular components. When this process is complete, the replaceable bud senesces and dies.
ARTICLE | doi:10.20944/preprints202306.1297.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: Heart failure; β-adrenergic receptor; cardiac fibrosis; cardiac inflammation; Bruton’s tyrosine kinase; Zanubrutinib
Online: 19 June 2023 (05:23:12 CEST)
(1) Background: Heart failure (HF) is the final stage of multiple cardiac diseases, which has now become a severe public health problem worldwide. β-Adrenergic receptor (β-AR) overactivation is a major pathological factor associated with multiple cardiac diseases and mediates cardiac fibrosis and inflammation. Previous study has demonstrated that Bruton's tyrosine kinase (BTK) mediated cardiac fibrosis by TGF-β related signal pathways, indicating that BTK was a potential drug target for cardiac fibrosis. Zanubrutinib, a second-generation BTK inhibitor, has shown anti-fibrosis effects in previous research. However, it is unclear whether Zanubrutinib can alleviate cardiac fibrosis induced by β-AR overactivation;(2) Methods: In vivo: Male C57BL/6J mice were treated with or without the β-AR agonist isoproterenol (ISO) to establish cardiac fibrosis animal model. Here, results showed that BTK inhibitor Zanubrutinib (ZB) had a great effect on cardiac fibrosis and inflammation induced by β-AR. In vitro: Results showed that ZB alleviated β-AR-induced cardiac fibroblast activation and macrophage proinflammatory cytokine production. Further mechanism studies demonstrated that ZB inhibited β-AR-induced cardiac fibrosis and inflammation by BTK、STAT3、NF-κB and PI3K/Akt signal pathways both in vivo and in vitro; (4) Conclusions: our research provides evidence that ZB ameliorates β-AR-induced cardiac fibrosis and inflammation.