The stimuli-responsive polypeptides have drawn extensive attention because of their promising applications in biotechnology considering their biocompatibility, biodegradability, and bioactivity. In ...this tutorial review, we summarize the most recent progress in this area, including thermo-, redox-, photo-, and biomolecule responsive polypeptides over the past decade. The design and synthesis of stimuli-responsive polypeptides will be briefly introduced. The correlation between the structure and properties, particularly the effects of polypeptide conformation, will be emphasized here. In addition, the applications of stimuli-responsive polypeptides in controlled drug release and tissue engineering are briefly discussed.
On January 3, 2019, China's Chang'e-4 probe, accomplishes the first-ever soft landing on Moon's farside in the Von Kármán crater floor mare volcanism plain (177.59°E, 45.46°S) within the South ...Pole-Aitken (SPA) basin. Its surface in-situ measurements would provide the first “ground truth” for lunar farside volcanism and SPA materials. We present a detailed geologic context, topographical, morphological, quantitative geochemical and mineralogical characterization of a 20 × 20 km area centered at the Chang'e-4 landing site, using the latest multi-source high-resolution orbital data sets. The landing area is very flat at a baseline of 30 m, with 90% of surface having slope <5°, and deficient of surface boulder exposures. The landing area mare is superposed by abundant sub-kilometer, block-poor circular impact craters and secondary craters in chains and clusters. Mare basalts at the landing site is dominated by low-titanium basalts, and appear to be less mafic and iron-depleted than all typical kinds of retuned lunar basalt samples and may represent a new kind of mare basalt. The landing site mare is heavily sculptured by a set of linear parallel ridged and furrowed textures formed by ballistic ejecta from the Finsen crater, which are characterized by a more feldspathic composition, while with elevated orthopyroxene abundance, and may represent compositional properties of the primitive SPA basin floor materials. We propose the Finsen ejecta and mare basalt outcrops at the landing area as prioritized targets for Chang'e-4 surface geological and spectroscopic explorations. Follow-on mission data interpretations should consider the mixing effect of local mare basalts and distant feldspathic materials.
•Chang’e-4 landed in farside Von Kármán crater floor mare plain (177.59°E, 45.46°S) within the South Pole-Aitken (SPA) basin.•The landing area mare basalts appear to be less mafic and iron-depleted than returned lunar basalt samples.•The landing area mare is sculptured by ejecta from the Finsen crater, which may represent primitive SPA composition.•Finsen ejecta and mare basalts are prioritized targets and mission data interpretations should consider the mixing effect.
X-ray diffraction patterns of Martian mudstones acquired by Chemistry & Mineralogy X-Ray Diffraction (CheMin) aboard Mars Science Laboratory (MSL) suggest that the smectites detected in Gale crater ...have poor crystallinity. This finding poses an urgent question about the structural ordering of phyllosilicates found globally by Visible/Near-Infrared (VIS-NIR) spectroscopic orbital remote sensing on Mars, linked to their formation conditions. In this study, we synthesized saponite (Nz+x/zM6Si8-xAlxO20(OH)4·nH2O, where M and N correspond to the divalent octahedral cations and the interlayer cations, respectively) with variable crystallinity, which bear structural similarities to the smectite discovered at Gale crater. Synthetic saponite was characterized using Field Emission Scanning Electron Microscopy (FE-SEM), powder X-ray diffraction (XRD), then studied the spectral features of these samples using nuclear magnetic resonance spectroscopy (NMR), Raman spectroscopy, and VIS-NIR reflectance spectroscopy. Our study revealed that the crystallinity of these saponite samples increased (as shown in the FWHM of XRD (060) peak), and is accompanied by (1) improved T-O-T layer stacking along the c axis (specified by the intensity and width of the XRD (001) peak); (2) increased uniformity of the SiO4 unit in tetrahedral sheets (based on the peak widths of Raman spectra and the well-resolved 29Si NMR peaks); (3) improved regularity in the distribution of Mg2+ in octahedral sites and thus the regularity of metal-OH bonds in octahedral sheet (based on the resolution of the NIR 2.2–2.4 μm band and the peak width of the XRD (060,330) peak); and (4) the increased Al in tetrahedral sites and decrease of Al in octahedral sites (the width of 27Al NMR peak), the crystallinity of saponite raised. Based on experimental observations, the first derivative spectra of metal-OH absorptions were proposed as a crystallinity index for smectite on Mars. Our results indicate that different vibration spectroscopy techniques can constrain the structural ordering of smectite on Mars and provide insight into their formation conditions.
•XRD and various spectroscopic methods indicate the improved structural ordering of synthetic saponite.•The NIR band in 2.2–2.4 μm exhibits obvious changes in the band resolution following the improved crystallinity.•The first derivative of metal-OH band at 2.2–2.4 μm was proposed to evaluate the structural ordering of smectites on Mars.
Lithium-ion batteries are the primary power source in electric vehicles, and the prognosis of their remaining useful life is vital for ensuring the safety, stability, and long lifetime of electric ...vehicles. Accurately establishing a mechanism model of a vehicle lithium-ion battery involves a complex electrochemical process. Remaining useful life (RUL) prognostics based on data-driven methods has become a focus of research. Current research on data-driven methodologies is summarized in this paper. By analyzing the problems of vehicle lithium-ion batteries in practical applications, the problems that need to be solved in the future are identified.
Background:
Dental pulp stem cells (DPSCs) are a unique source for future clinical application in dentistry such as periodontology or endodontics. However, DPSCs are prone to apoptosis under abnormal ...conditions. Taxifolin is a natural flavonoid and possesses many pharmacological activities including anti-hypoxic and anti-inflammatory. We aimed to elucidate the mechanisms of taxifolin protects DPSC under hypoxia and inflammatory conditions.
Methods:
DPSCs from human dental pulp tissue was purchased from Lonza (cat. no. PT-5025. Basel, Switzerland)) and identified by DPSC’s biomarkers. DPSC differentiation in vitro following the manufacturers’ instructions. ARS staining and Oil red staining verify the efficiency of differentiation in vitro after 2 weeks. The changes of various genes and proteins were identified by Q-PCR and western-blot, respectively. Cell viability was determined by the CCK-8 method, while apoptosis was determined by Annexin V/PI staining.
Results:
DPSC differentiation in vitro shows that hypoxia and TNF-α synergistically inhibit the survival and osteogenesis of DPSCs. A final concentration of 10 μM Taxifolin can significantly reduce the apoptosis of DPSCs under inflammation and hypoxia conditions. Taxifolin substantially increases carbonic anhydrase IX (CA9) expression but not HIF1a, and inhibitions of CA9 expression nullify the protective role of taxifolin under hypoxia and inflammatory condition.
Conclusion:
Taxifolin significantly increased the expression of CA9 when it inhibits DPSC apoptosis and taxifolin synergistically to protect DPSCs against apoptosis with CA9 under hypoxia and inflammatory conditions. Taxifolin can be used as a potential drug for clinical treatment of DPSC-related diseases.
A series of new functional amino acids were prepared in high yield via thiol–ene Michael addition between l-cysteine and monomethoxy oligo(ethylene glycol) (OEG) functionalized methacrylates (OEG x ...MA) and acrylate (OEG x A). These OEGylated cysteine derivatives were converted into polymerizable N-carboxyanhydride (NCA) monomers using triphosgene. Subsequent ring-opening polymerization (ROP) of these NCA monomers gave a series of OEGylated poly-l-cysteine (poly-EG x MA-C or poly-EG x A-C) homopolypeptides. Depending on the length of OEG side chains, poly-EG x MA-C and poly-EG x A-C polypeptides displayed different solubility and secondary structure in water. More importantly, the obtained polypeptides can display reversible thermoresponsive properties in water when the x value is between 3 and 5. The synthetic strategy represents a highly efficient method to prepare nonionic functional polypeptides with tunable thermoresponsive properties.
The oxidation-responsive behaviors of OEGylated poly-l-cysteine homopolypeptides, that is, poly(l-EG x MA-C) n , were investigated. These poly-l-cysteine derivatives adopted mixed conformation in ...water, in which the β-sheet accounted for a significant proportion. Upon oxidation, the thioethers in polypeptide side chains were converted to polar sulfone groups, which triggered the secondary structure transition from β-sheet preferred conformation to random coil. Accordingly, the increase of side-chain polarity together with conformation changes increased samples’ water solubility and cloud point temperature. Using mPEG45-NH2 as macroinitiator, we synthesized PEG45-b-poly(l-EG2MA-C)22 diblock copolymer via ring-opening polymerization (ROP) of l-EG2MA-C N-carboxyanhydride (NCA). The PEG45-b-poly(l-EG2MA-C)22 was able to self-assemble into spherical micelles in aqueous solution, and the micelles could undergo an oxidation-triggered disassembly due to the oxidation-responsive thioethers. Such a new class of oxidation-responsive polypeptides might provide a promising platform to construct inflammation targeting drug delivery systems.
We conducted comprehensive Raman and Fourier transform infrared (FTIR) spectroscopic studies on the whole rock and lithic clasts of Northwest Africa (NWA) 4884 to constrain its igneous mineralogy and ...metamorphic characteristics. NWA 4884 is composed of mostly clinopyroxene (25.8 vol.%), pigeonite (16.6 vol.%), plagioclase (26.6 vol.%), maskelynite (8.1 vol.%), olivine (20.7 vol.%), minor tridymite (1.0 vol.%), quartz (0.2 vol.%), and ilmenite (0.5 vol.%). Lithic clasts contain mafic rocks including plutonic ultramafic cumulate, olivine gabbro, mare basalt, and feldspathic rocks including noritic anorthosite and impact melt breccia. Raman and FTIR spectroscopic analyses are combined to investigate the shock history of this breccia and revealed that NWA 4884 is highly shocked (17.9–48.1 GPa recorded in plagioclase). The combination of bulk composition and remote sensing data provides possible source regions of NWA 4884: the southern Lacus Veris (20.5°S, 84.5°W) within Orientale basin and the western mare unit (45.3°N, 151.3°E) of Campbell Crater. The pairing relationship among NWA 4884, Yamato 793274, Queen Alexandra Range 94281, and NWA 7611 is supported by their petrographic, mineral, and compositional similarities. Our work demonstrates the potential of Raman and FTIR spectroscopies to shed light on igneous petrology and the bombardment history of the Moon.
Petrographic and Raman spectral studies of Northwest Africa (NWA) 4884 indicate that lithic clasts in NWA 4884 contain mafic rocks including plutonic ultramafic cumulate, olivine gabbro, mare basalt, and feldspathic rocks including noritic anorthosite and impact melt breccia. Raman and Fourier transform infrared spectroscopic analyses revealed that plagioclase in NWA 4884 is highly shocked (17.9–48.1 GPa). The combination of bulk composition and remote sensing data provides possible source regions of 4884: the southern Lacus Veris (20.5°S, 84.5°W) within Orientale basin and the western mare unit (45.3°N, 151.3°E) of Campbell Crater. The pairing relationship among NWA 4884, Yamato 793274, QUE 94281, and NWA 7611 is supported by their petrographic, mineral, and compositional similarities.
Background
Cancer-associated fibroblasts (CAFs) are involved in tumor growth, angiogenesis, metastasis, and resistance to therapy. We sought to explore the CAFs characteristics in hepatocellular ...carcinoma (HCC) and establish a CAF-based risk signature for predicting the prognosis of HCC patients.
Methods
The signal-cell RNA sequencing (scRNA-seq) data was obtained from the GEO database. Bulk RNA-seq data and microarray data of HCC were obtained from the TCGA and GEO databases respectively. Seurat R package was applied to process scRNA-seq data and identify CAF clusters according to the CAF markers. Differential expression analysis was performed to screen differentially expressed genes (DEGs) between normal and tumor samples in TCGA dataset. Then Pearson correlation analysis was used to determine the DEGs associated with CAF clusters, followed by the univariate Cox regression analysis to identify CAF-related prognostic genes. Lasso regression was implemented to construct a risk signature based on CAF-related prognostic genes. Finally, a nomogram model based on the risk signature and clinicopathological characteristics was developed.
Results
Based on scRNA-seq data, we identified 4 CAF clusters in HCC, 3 of which were associated with prognosis in HCC. A total of 423 genes were identified from 2811 DEGs to be significantly correlated with CAF clusters, and were narrowed down to generate a risk signature with 6 genes. These six genes were primarily connected with 39 pathways, such as angiogenesis, apoptosis, and hypoxia. Meanwhile, the risk signature was significantly associated with stromal and immune scores, as well as some immune cells. Multivariate analysis revealed that risk signature was an independent prognostic factor for HCC, and its value in predicting immunotherapeutic outcomes was confirmed. A novel nomogram integrating the stage and CAF-based risk signature was constructed, which exhibited favorable predictability and reliability in the prognosis prediction of HCC.
Conclusion
CAF-based risk signatures can effectively predict the prognosis of HCC, and comprehensive characterization of the CAF signature of HCC may help to interpret the response of HCC to immunotherapy and provide new strategies for cancer treatment.
•The electrostatic discharge (ESD) induced by Martian dust activities may cause the formation of color centers in NaCl.•The Cl released from NaCl crystals during Mars dust event may play an important ...role in perchlorate formation.•The possibility of color centers in NaCl may shed light on the detection of normally featureless chlorides on Mars.
The electrostatic discharge (ESD) induced by Martian dust activities (dust storms, dust devils, and grain saltation) has been recently proposed as a powerful geological agent to modify the structure and chemistry of Martian salts. Here, we performed new experiments to simulate gas discharge in Martian dust activity in a Mars chamber to investigate the modifications of chloride exposed to a medium strength ESD process. The structural, chemical and spectral features of NaCl before and after ESD exposure were systematically characterized with multiple analysis methods. On the basis of the experimental results, we found that 1) the colorless NaCl precursor subjected to ESD exposure subsequently displayed violet/blue color, indicating the presence of color centers; 2) the color centers (VK centers and Na colloids) in NaCl cause strong and characteristic spectral features in the visible to near-infrared reflectance spectra and Raman spectra; and 3) the relative density of color centers (VK centers and Na colloids) in NaCl gradually changes with increasing ESD duration. Our results also suggest that preferential Cl was released within NaCl crystals during the ESD process, and new phases ClO3−, ClO4−, and CO32− formed, which is consistent with previous studies (Wang et al., 2020b; Wu et al., 2018). We interpreted that preferential Cl release within NaCl crystals should be associated with the decomposition of VK centers and the sputtering process. We also proposed that the chemically active Cl species released from solid NaCl crystals is an essential part of the overall reaction pathway of perchlorate formation on Mars. Chloride exposed to the radiation environment at the Martian surface may also contain color centers, shedding light on the detection of normally featureless chlorides on Mars.
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