The present work focuses on the enhanced resistance of ceramic precursor modified expandable graphite to hypersonic aerodynamic heating of ablative-resistant coating. Expandable graphite (EG) was ...modified by some coupling agents and boric acid to increase the interaction force between inorganic fillers and epoxy resin phases. A novel epoxy-based ablative-resistant coating is developed using modified EG, zinc borate, E-glass fibers and epoxy resin. The SEM and XPS measurements showed that the silane function groups have been attached on the surface of EG and boric silicon compound was also deposited on the surface of EG as ceramic precursor. Boric silicon compound is deposited on the surface of EG as ceramic precursor. Coating heat-resistant performance tests using Muffle stove showed that the coating with EG modified by
ND-42
and boric acid has a uniform expansion of carbon layer with good integrity and high strength. Furthermore, it is observed that the back surface of the samples coated with ablation-resistant coating can be cooled to below 270 ℃ in a thermal test by a FD-04D/E Wind Tunnel, and the uniformly expanded and dense carbon char is seen in the SEM images, which indicated that the coating is characterized by good heat-insulation and heat-resistant parameters.
Inspired by the fact that nanostructured expandable graphite (denoted as EG), when functionalized with silicon (Si) and boron (B) elements, can significantly enhance thermal insulation performance ...and improve the strength of char residue layers, the study controllably synthesizes EG supported with boron acid (H
3
BO
3
) or polyhedral oligomeric silsesquioxane (POSS), using polydopamine (PDA) as a bridging agent. The resulting composites possess specific particle sizes of 80–90 nm and 100–120 nm for H
3
BO
3
-PDA-EG and POSS-PDA-EG, respectively. By formulating ablative-resistant coatings incorporating these composites, significant improvements are achieved in the mechanical properties of the resulting ceramic layers formed during ablation compared to control formulation. The compressive strength of the char residue layer is 0.13 MPa for EG alone, 8.85 MPa for H
3
BO
3
-PDA-EG, and 12.86 MPa for POSS-PDA-EG. Additionally, it is observed that the back surface of the coating with POSS-PDA-EG is approximately 180 ℃, while the back surface of the coating with H
3
BO
3
-PDA-EG is approximately 300 ℃ in a thermal test by a FD-04D/E Wind Tunnel, and compared to the coating with H
3
BO
3
-PDA-EG, the coating with POSS-PDA-EG yields more uniformly expanded and dense residue, which indicated that the coating with POSS-PDA-EG is characterized by better heat insulation and heat-resistant parameters. This is attributed to the improved silicon-boron coordination effect facilitated by the presence of POSS-PDA-EG and boron oxide, promoting ceramization. The resulting graphitized carbon layer, formed through fusion with porous expanded graphite at high temperatures, effectively resists high heat flow erosion over an extended duration. This work introduces an effective approach for enhancing ablation resistance by synergistically catalyzing boric acid or POSS-modified EG with a PDA bridge. The initial decomposition temperature was increased from 189 to 223 ℃, the maximum decomposition temperature was increased from 282 to 287℃, and the residual weight was increased from 51.6 to 63.6%. This can be concluded that the mixture of epoxy resin with either H
3
BO
3
-PDA-EG or POSS-PDA-EG demonstrates outstanding thermal resistance. The utilization of these novel composites and the insights gained from their performance contribute to advancements in the field of ablation-resistant coatings.
A novel fluorescent probe based on functional mesoporous material (denoted as SBA-KH-2py) with high sensitivity and selectivity of detecting silver ions (Ag
+
) was designed and prepared by ...immobilizing (4-nitro-2-((pyridin-2-ylmethylene) amino) aniline (denoted as 2py-Schiff base) within the channels of mesoporous material. The 2py-Schiff base was successively loaded within the framework of mesoporous material by the organic silane coupling agent, and the ordered channels were still retained. With the increasing loading amounts of Schiff base, the fluorescence intensities of functional materials also were enhanced in the fluorescent spectra excited by the same wavelengths. Especially, the material SBA-KH-20%-2py possesses the strongest fluorescence intensity. Moreover, in the recognition experiments, it can definitely distinguish Ag
+
ions in aqueous solutions, which shows the excellent selectivity and high sensitivity.
Abstract
Ultrahot Jupiters (UHJs) possess the most extreme environments among various types of exoplanets, making them ideal laboratories to study the chemical composition and kinetics properties of ...exoplanet atmosphere with high-resolution spectroscopy. It has the advantage of resolving the tiny Doppler shift and weak signal from exoplanet atmosphere and has helped to detect dozens of heavy elements in UHJs including KELT-9b, WASP-76b, and WASP-121b. MASCARA-4b is a 2.8 days UHJ with an equilibrium temperature of ∼2250 K, which is expected to contain heavy elements detectable with the Very Large Telescope (VLT). In this letter, we present a survey of atoms/ions in the atmosphere of the MASCARA-4b, using the two VLT/ESPRESSO transits data. Cross-correlation analyses are performed on the obtained transmission spectra at each exposure with the template spectra generated by
petitRADTRANS
for atoms/ions from element Li to U. We confirm the previous detection of Mg, Ca, Cr, and Fe, and report the detection of Rb, Sm, Ti+, and Ba+ with peak signal-to-noise ratios (S/Ns) > 5. We report a tentative detection of Sc+, with peak S/Ns ∼ 6 but deviating from the estimated position. The most interesting discovery is the first-time detection of elements Rb and Sm in an exoplanet. Rb is an alkaline element like Na and K, while Sm is the first lanthanide series element and is by far the heaviest one detected in exoplanets. Detailed modeling and acquiring more data are required to yield abundance ratios of the heavy elements and to understand better the common presence of them in UHJ’s atmospheres.
Metabolic diseases, such as diabetes, obesity, and fatty liver disease, have now reached epidemic proportions. Receptor tyrosine kinases (RTKs) are a family of cell surface receptors responding to ...growth factors, hormones, and cytokines to mediate a diverse set of fundamental cellular and metabolic signaling pathways. These ligands signal by endocrine, paracrine, or autocrine means in peripheral organs and in the central nervous system to control cellular and tissue-specific metabolic processes. Interestingly, the expression of many RTKs and their ligands are controlled by changes in metabolic demand, for example, during starvation, feeding, or obesity. In addition, studies of RTKs and their ligands in regulating energy homeostasis have revealed unexpected diversity in the mechanisms of action and their specific metabolic functions. Our current understanding of the molecular, biochemical and genetic control of energy homeostasis by the endocrine RTK ligands insulin, FGF21 and FGF19 are now relatively well understood. In addition to these classical endocrine signals, non-endocrine ligands can govern local energy regulation, and the intriguing crosstalk between the RTK family and the TGFβ receptor family demonstrates a signaling network that diversifies metabolic process between tissues. Thus, there is a need to increase our molecular and mechanistic understanding of signal diversification of RTK actions in metabolic disease. Here we review the known and emerging molecular mechanisms of RTK signaling that regulate systemic glucose and lipid metabolism, as well as highlighting unexpected roles of non-classical RTK ligands that crosstalk with other receptor pathways.
The secreted protein isthmin-1 (Ism1) mitigates diabetes by increasing adipocyte and skeletal muscle glucose uptake by activating the PI3K-Akt pathway. However, while both Ism1 and insulin converge ...on these common targets, Ism1 has distinct cellular actions suggesting divergence in downstream intracellular signaling pathways. To understand the biological complexity of Ism1 signaling, we performed phosphoproteomic analysis after acute exposure, revealing overlapping and distinct pathways of Ism1 and insulin. We identify a 53% overlap between Ism1 and insulin signaling and Ism1-mediated phosphoproteome-wide alterations in ~450 proteins that are not shared with insulin. Interestingly, we find several unknown phosphorylation sites on proteins related to protein translation, mTOR pathway, and, unexpectedly, muscle function in the Ism1 signaling network. Physiologically,
ablation in mice results in altered proteostasis, including lower muscle protein levels under fed and fasted conditions, reduced amino acid incorporation into proteins, and reduced phosphorylation of the key protein synthesis effectors Akt and downstream mTORC1 targets. As metabolic disorders such as diabetes are associated with accelerated loss of skeletal muscle protein content, these studies define a non-canonical mechanism by which this antidiabetic circulating protein controls muscle biology.
A novel phosphorus-silicon flame retardant (P
PSQ) was prepared by bonding phosphate to silicon-based polysilsesquioxane (PSQ) and used as flame retardant of poly (lactic acid) (PLA). The results ...show that PLA with 10 wt % P
PSQ has a limiting oxygen index (LOI) 24.1%, the peak heat release rate (PHRR) and total heat release (THR) of PLA decrease 21.8% and 25.2% compared to neat PLA in cone calorimetric test, indicating that P
PSQ shows better flame retardancy in comparison to PSQ. Furthermore, the study for the morphology and composition of carbon residue after the combustion of PLA and the gas release of PLA during combustion illustrate that P
PSQ has flame retardancy in condensed phase and gas phase simultaneously. In condensed phase, phosphorus from phosphate promotes the formation of more stable and better carbon layer containing Si and P, which inhibits the transfer of heat and oxygen in the combustion. In gas phase, the phosphate in P
PSQ emits phosphorus-containing compound that can restrain the release of C-O containing products, which may have effective flame retardancy for PLA in gas phase to a certain extent. In one word, P
PSQ is denoted as a good phosphorus-silicon synergistic flame-retardant.
Objective Correct diagnosis and prognostic evaluation of medullary thyroid cancer (MTC) are crucial to treat patients. The purpose of this study was to evaluate the diagnostic and prognostic value of ... 18 FF-DOPA PET/CT in patients with MTC. Methods We reviewed MTC patients who underwent 18 FF-DOPA PET/CT from June 2008 to November 2023. Clinical characteristics, follow-up data, and the following 18 FF-DOPA PET/CT parameters were recorded: maximum standardized uptake value (SUV max ), mean standardized uptake value (SUV mean ), metabolic tumor volume (MTV), and SUV mean of multiple organs. The diagnostic value of PET/CT for the detection of tumor lesions was calculated. Serum basal calcitonin (bCt) and stimulated calcitonin (sCt) were determined. Receiver operating characteristics, Kaplan–Meier, and Cox regression analyses were performed. Results In total, 109 patients (50 women, 59 men; average age, 55 ± 14 years) were included in the analysis. The patient-related sensitivity, specificity, and accuracy of 18 FF-DOPA PET/CT were 95%, 93%, and 94%, respectively. The lesion-related sensitivity, specificity, and accuracy were 65%, 99%, and 72%, respectively. The optimal cutoff values of bCt, sCt, and CEA to obtain positive 18 FF-DOPA PET/CT results were 64 pg/mL, 1808 pg/mL, and 4 µg/L, respectively. Patients with negative 18 FF-DOPA PET/CT had longer overall survival than patients with positive 18 FF-DOPA PET/CT results ( P = 0.017). Significant positive correlations were found between bCt, sCt, and CEA with SUV max , SUV mean , and MTV of 18 FF-DOPA PET/CT ( P < 0.001). 18 FF-DOPA PET/CT results and MTV may be useful for the evaluation of the prognosis of patients with recurrent MTC, while age and MTV were independent prognostic factors in patients with primary MTC. For all patients, SUV mean of the left kidney, liver, aorta, and pancreas might be used to independently predict OS. Conclusion 18 FF-DOPA PET/CT had great value for diagnosis and prognostic assessment in patients with MTC. The DOPA PET/CT parameter SUV mean and MTV showed significant association with OS.
Layered Li‐rich cathode materials with high reversible energy densities are becoming prevalent. However, owing to the activation of low‐potential redox couples and the progressively irreversible ...structural transformation caused by the local adjustment of transition‐metal ions in the intra/interlayer driven by anionic redox, continuous capacity degradation, and voltage decay emerge, thus greatly reducing the energy density and increasing the difficulty of battery system management. Herein, layered Li‐rich cathode materials with higher intralayer configuration entropy have more local structural diversity and higher distortion energy, resulting in superior local structural adaptability with no drastic redox couple evolution, major local structural adjustment, or obvious layered‐to‐spinel phase transition. Consequently, the energy retention of the entropy‐stabilization‐strategy‐enhanced Li‐rich cathode materials is almost twice that of a typical Li‐rich cathode material (Li1.20Mn0.54Ni0.13Co0.13O2, T‐LRM) after 3 months of cyclic testing. Moreover, when cycled at 1 C, the voltage degradation per cycle is less than 0.02%, that is, it results in a voltage loss of only 0.8 mV per cycle, which is excellent performance. This study paves the way for the development of Li‐rich cathode materials with stabilized intralayer atomic arrangements and high local structural adaptability.
Layered Li‐rich cathode materials with higher intralayer configuration entropy have more local structural diversity and higher distortion energy, resulting in superior local structural adaptability: no drastic redox couple evolution, major local structural adjustment, or obvious layered‐to‐spinel phase transition. This leads to high stability of the capacity and voltage, greatly enhancing energy retention.
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![The role of [18F]F-DOPA PET...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/2235-0802_2235-0640/small "The role of [18F]F-DOPA PET/CT in diagnostic and prognostic assessment of medullary thyroid cancer: a 15-year experience with 109 patients")
