ABSTRACT
Developing carbon encapsulated magnetic composites with rational design of microstructure for achieving high-performance electromagnetic wave (EMW) absorption in a facile, sustainable, and energy-efficiency approach is highly demanded yet remains challenging. Here, a type of N-doped carbon nanotube (CNT) encapsulated CoNi alloy nanocomposites with diverse heterostructures are synthesized via the facile, sustainable autocatalytic pyrolysis of porous CoNi-layered double hydroxide/melamine. Specifically, the formation mechanism of the encapsulated structure and the effects of heterogenous microstructure and composition on the EMW absorption performance are ascertained. With the presence of melamine, CoNi alloy emerges its autocatalysis effect to generate N-doped CNTs, leading to unique heterostructure and high oxidation stability. The abundant heterogeneous interfaces induce strong interfacial polarization to EMWs and optimize impedance matching characteristic. Combined with the inherent high conductive and magnetic loss capabilities, the nanocomposites accomplish a high-efficiency EMW absorption performance even at a low filling ratio. The minimum reflection loss of -84.0 dB at the thickness of 3.2 mm and a maximum effective bandwidth of 4.3 GHz are obtained, comparable to the best EMW absorbers. Integrated with the facile, controllable, and sustainable preparation approach of the heterogenous nanocomposites, the work shows a great promise of the nanocarbon encapsulation protocol for achieving lightweight, high-performance EMW absorption materials.
ABSTRACT
The advantages of sodium metal, such as abundant resources, low cost, high capacity, and high working potential, make it a promising metal anode. Unfortunately, the hazardous dendrite growth of sodium metal is one of the major hindrances for the practical application of sodium metal batteries (SMBs). By applying multifunctional Mg(II)@Ti3 C2 MXene as the protective layer for commercial Cu foil, the wettability of the electrolyte on the current collector is dramatically improved with the suppression of sodium dendrites. Moreover, the first-principles calculations prove that the surface of Mg(0001) is able to establish a connection with Na(111) growth, with Mg acting as the nucleation seed for sodium. The experimental results indicate that even when a high areal capacity of sodium (2 mAh cm-2 ) is deposited, no sodium dendrite is observed. Electrochemical tests, including symmetric cells, Na||Cu asymmetric cells, and full cells, prove the sodiophilic character of Mg2+ -decorated Ti3 C2 MXene. The results may also create a new pathway for developing other dendrite-free metal anodes, such as Li/K/Zn/Ca/Mg.
ABSTRACT
With the advantages of high theoretical-specific capacity and lowest working potential, lithium metal anode is considered as the most promising anode for next-generation batteries. Here, a scalable dealloying method is developed to prepare nano-sized bismuth (Bi). It is found that the Bi-modification can not only enhance the wettability of the commercial polyethylene separator but also suppresses the lithium dendrite growth. With the nano-sized Bi modified separator, 5V-class lithium metal batteries with commercial carbonate-based electrolyte show a 91% capacity retention ratio after 800 cycles. First-principle calculations prove that lithium atoms tend to deposit smoothly on the Bi surface. Moreover, for potassium ion batteries, nano-sized Bi shows a stable cycling performance and high capacity. The results may be useful for the development of high-energy and high-safety batteries.
ABSTRACT
INTRODUCTION: In the event of radiological accidents and cancer radiotherapies in the clinic, the gastrointestinal (GI) system is vulnerable to ionizing radiation and shows GI injury. Accessible biomarkers may provide means to predict, evaluate, and treat GI tissue damage. The current study investigated radiation GI injury biomarkers in rat plasma. MATERIAL AND METHODS: High-coverage targeted lipidomics was employed to profile lipidome perturbations at 72 h after 0, 1, 2, 3, 5, and 8 Gy (60Co γ-rays at 1 Gy/min) total-body irradiation in male rat jejunum. The results were correlated with previous plasma screening outcomes. RESULTS: In total, 93 differential metabolites and 28 linear dose-responsive metabolites were screened in the jejunum. Moreover, 52 lipid species with significant differences both in jejunum and plasma were obtained. Three lipid species with linear dose-response relationship both in jejunum and plasma were put forth, which exhibited good to excellent sensitivity and specificity in triaging different exposure levels. DISCUSSION: The linear dose-effect relationship of lipid metabolites in the jejunum and the triage performance of radiation GI injury biomarkers in plasma were studied for the first time. CONCLUSION: The present study can provide insights into expanded biomarkers of IR-mediated GI injury and minimally invasive assays for evaluation.
Subject(s)
Lipidomics , Whole-Body Irradiation , Animals , Biomarkers/metabolism , Gamma Rays , Lipids , Male , RatsABSTRACT
The structural, electronic and vibrational properties of a water layer on Ag(100) and Ag(511) have been studied by first-principles calculations and ab initio molecular dynamics simulations. The most stable water structure on the Ag(100) and Ag(511) surfaces have been obtained. The AIMD results showed rather high stability of the water layer on the stepped surface at 140 K, indicating a crystal-like structure with long-range ordering. The calculated vibrational spectra at 140 K showed good agreement with the experimental results. On the Ag(100) surface, a red-shift was observed when the temperature increased from 140 K to 300 K caused by the change in the number of H-bonded (HB) hydrogen. On Ag(511), a three-fold splitting of the O-H stretch mode was observed. This can be explained by the special water structure at the stepped Ag surface: the relatively strong water-metal interaction at the step edge and weak water-terrace interaction/strong water-water interaction at the terrace, which can also explain the high stability of the water layer on the Ag(511) surface.
ABSTRACT
In this work, by combining density functional theory calculations and Monte Carlo simulations with cluster expansion Hamiltonian methods, we investigate the surface aggregation of Pt atoms on the Pt/Ag(111) surface under vacuum conditions and in the presence of CO. The results show the decisive influence of CO-CO interactions and reveal the competition between CO-metal interactions and CO-CO repulsion. Thus, in addition to evidence of reverse Pt segregation caused by CO adsorption, two methods for tuning the surface Pt atomic system synthesis are found, where the surface can be adjusted by tuning the CO coverage to obtain a larger number of monomers (0.25 ML CO coverage) or a pure Pt layer (1 ML coverage) at Pt bulk concentrations above 10%. For highly dilute alloys, the Pt distribution can be controlled by adjusting the concentration. Indeed, for a Pt bulk concentration close to 8% and a CO coverage of about less than 1 ML, between 400 and 600 K, an ordered structure has been observed which maximized the number of Pt monomers and homogeneous distribution on the surface. The overpotential (η) of the ordered Pt3Ag(111) surface is 0.41 V, slightly lower than that of pure Pt(111) (η = 0.43 V), indicating a potential candidate for ORR catalysts with rich active sites and a low overpotential.
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In this work, the surface structure of a PdAg alloy is investigated by cluster expansion (CE) combined Monte Carlo (MC) simulations. All systems with different component proportions show an obvious component segregation corresponding to the depth from the surface. A significant amount of Ag is observed on the first layer, and Pd is concentrated significantly on the second layer. The Pd distribution on the PdAg surfaces is closely related to the temperature and composition ascribed to the concentration and configurational entropy effects, which are explicitly treated in MC simulations. The vacancies mainly distribute separately. The simulation results show good agreement with the experimental evidence. Moreover, we demonstrated a general and highly effective casting combined quenching strategy for controlling the ensemble size and chemical composition of alloy surfaces which could successfully be applied to the large-scale production of SAA.
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In this paper, the Wulff cluster model which has been proved to successfully describe the melt structure of pure metals, homogenous alloys and eutectic alloys has been extended to an alloy with intermetallic compounds (In50Bi50). According to the cohesive energy and the solid-state XRD patterns, the most possible types of clusters in the melt are Bi and InBi. At relatively high temperatures, the superimposed XRD (simulated) patterns of Bi and InBi clusters are in good agreement with the experimental HTXRD patterns in terms of the position and intensity of the peaks. With the decrease of temperature, there is an obvious deviation in the simulated XRD value at the second peak caused by the nucleation process of Bi clusters, which would be modified by adding simulated XRD patterns of the Bi bulk. The proportion of the superimposed Bi bulk XRD pattern increases with the decrease of temperature suggesting that the nucleation process of the Bi cluster begins at 160 °C.
ABSTRACT
In the present work, the Wulff cluster model, which has been proved to be successful for pure metals and homogeneous alloys, has been extended to eutectic alloys (Ag-Cu and Al-Si). In our model, the shapes of the clusters in melts were determined by the interfacial energy calculated by density functional theory (DFT) of different facet families based on Wulff theory. The cluster size was given by the pair distribution function (PDF) g(r), which was converted from experimental high-temperature X-ray diffraction (HTXRD). The simulated XRD curves in the high temperature region were in good agreement with the experimental results. For the Al-Si alloy, a deviation of the intensity and position of the second peak near the eutectic temperature was observed. The simulated results after structure and composition modification corresponded to the experimental ones. It indicates that the deviation is mainly related to the significant change of the cluster size during Si clusters' growth processes before nucleation. Differently, there are no such nucleation processes at temperatures near the eutectic point due to the relatively high nucleation barriers of the two components in the Ag-Cu alloy.
ABSTRACT
In the present work, a new liquid metal model (Wulff cluster model) which has been proved to describe the structures of pure metal melts has been extended to binary homogeneous alloy melts (Cu-Ni and Ag-Au). The shapes of the nano-particles are determined by surface energies of different families of crystal planes, calculated by density functional theory (DFT), whereas the size was given by the pair distribution function (PDF) g(r) which was converted from experimental high-temperature X-ray diffraction (HTXRD). We demonstrated that the simulated X-ray diffraction (XRD) curves from present models match the experimental results quite well at high temperatures above the liquid-solid two-phase region, including not only the position and width of the peaks but also the relative intensity of the first and second peaks. Moreover, when the temperature is near the liquid-solid two-phase region, our model also fits the experimental strength curve well after modification using the solid XRD pattern of a relatively high melting point metal instead of its nano-particle. The agreement indicates the nucleation processes in homogeneous alloy melts.
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Chromosome damage is related to DNA damage and erroneous repair. It can cause cell dysfunction and ultimately induce carcinogenesis. Histone acetylation is crucial for regulating chromatin structure and DNA damage repair. Ionizing radiation (IR) can alter histone acetylation. However, variations in histone acetylation in response to IR exposure and the relationship between histone acetylation and IR-induced chromosome damage remains unclear. Hence, this study investigated the variation in the total acetylation levels of H3 and H4 in human lymphocytes exposed to 0-2 Gy 60Co γ-rays. Suberoylanilide hydroxamic acid (SAHA), a histone deacetylase (HDAC) inhibitor, was added to modify the histone acetylation state of irradiated cells. Then, the total acetylation level, enzyme activity, dicentric plus centric rings (dic + r) frequencies, and micronucleus (MN) frequencies of the treated cells were analyzed. Results indicated that the acetylation levels of H3 and H4 significantly decreased at 1 and 24 h, respectively, after radiation exposure. The acetylation levels of H3 and H4 in irradiated groups treated with SAHA were significantly higher than those in irradiated groups that were not treated with SAHA. SAHA treatment inhibited HDAC activity in cells exposed to 0-1 Gy 60Co γ-rays. SAHA treatment significantly decreased dic + r/cell and MN/cell in cells exposed to 0.5 or 1.0 Gy 60Co γ-rays relative to that in cells that did not receive SAHA treatment. In conclusion, histone acetylation is significantly affected by IR and is involved in chromosome damage induced by 60Co γ-radiation.
Subject(s)
Chromosomes, Human/genetics , Cobalt Radioisotopes/adverse effects , Gamma Rays/adverse effects , Histones/metabolism , Lymphocytes/radiation effects , Acetylation/drug effects , Acetylation/radiation effects , Cell Line , Histone Deacetylase Inhibitors/pharmacology , Humans , Hydroxamic Acids/pharmacology , Lymphocytes/cytology , Lymphocytes/drug effects , Lymphocytes/metabolism , VorinostatABSTRACT
The dose effect between nucleoplasmic bridges (NPB) and relatively low doses of ionising radiation remains unknown. Accordingly, this study investigated the NPB frequencies in human peripheral blood lymphocytes exposed to low-dose (60)Co γ-rays. Complex anomalies, including fused nuclei (FUS), horse-shoe nuclei (HS) and circular nuclei (CIR), which possibly originated from multiple NPBs, were also scored. Human peripheral blood samples were collected from three healthy males and irradiated with 0-1 and 0-0.4 Gy (60)Co γ-rays. A cytokinesis-block micronucleus cytome assay was then conducted to analyse NPB, PFHC (NPB plus three complex nuclear anomalies) and micronucleus (MN) in binucleated cells. All dose-response curves followed the linear model for both NPB frequency and PFHC cell frequency. The dose-response curves between NPB frequency and absorbed dose at 0-1 and 0-0.4 Gy were y = 0.0037x + 0.0005 (R (2) = 0.979, P < 0.05) and y = 0.0043x + 0.0004 (R (2) = 0.941, P < 0.05), respectively. The dose-response curves between PFHC cell frequency and absorbed dose at 0-1 and 0-0.4 Gy were y = 0.0044x + 0.0007 (R (2) = 0.982, P < 0.05) and y = 0.0059x + 0.0005 (R (2) = 0.969, P < 0.05), respectively. The statistical significance of differences between the irradiated groups (0-0.4 Gy) and background levels of NPB, PFHC and MN were also analysed. The lowest analysable doses of NPB, PFHC and MN were 0.12, 0.08 and 0.08 Gy, respectively. In conclusion, NPBs and PFHC positively correlated with the absorbed radiation at a relatively low dose.
Subject(s)
Gamma Rays , Lymphocytes/radiation effects , Micronuclei, Chromosome-Defective , Adult , Cells, Cultured , Dose-Response Relationship, Radiation , Humans , Male , Micronucleus TestsABSTRACT
Conversion of lignocellulosic material to ethanol is a major challenge in second generation bio-fuel production by yeast Saccharomyces cerevisiae. This report describes a novel strategy named "two-stage transcriptional reprogramming (TSTR)" in which key gene expression at both glucose and xylose fermentation phases is optimized in engineered S. cerevisiae. Through a combined genome-wide screening of stage-specific promoters and the balancing of the metabolic flux, ethanol yields and productivity from mixed sugars were significantly improved. In a medium containing 50g/L glucose and 50g/L xylose, the top-performing strain WXY12 rapidly consumed glucose within 12h and within 84h it consistently achieved an ethanol yield of 0.48g/g total sugar, which was 94% of the theoretical yield. WXY12 utilizes a KGD1 inducible promoter to drive xylose metabolism, resulting in much higher ethanol yield than a reference strain using a strong constitutive PGK1 promoter. These promising results validate the TSTR strategy by synthetically regulating the xylose assimilation pathway towards efficient xylose fermentation.
Subject(s)
Ethanol/metabolism , Gene Expression Regulation, Fungal/genetics , Metabolic Engineering , Promoter Regions, Genetic , Saccharomyces cerevisiae , Transcription, Genetic/genetics , Xylose/metabolism , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolismABSTRACT
In order to investigate the structure of FeAl mesoscopic crystals segregating in liquid state alloys, we have determined their equilibrium structures (Wulff shape) based on the Wulff cluster model. For non-stoichiometric surface terminations, the chemical environment is taken into account through the chemical potential of the constituents. In this case, different cluster shapes change as a function of the chemical environment. In order to model the growth process in more detail, we propose a quasi-static growth model based on the sequential addition of (sub-)monolayers in the most favorable surface directions. Thus, a sequence of different Wulff shapes results in the growth process, as illustrated for the FeAl intermetallic compound. This model is proved preliminarily by calculating the concentration trend of Al/Fe atoms on both Al-terminated and Fe-terminated surfaces, and by simulating the most stable layer adsorbed on these two surfaces. This model might be helpful in analyzing the growth processes including nucleation barriers during nucleation processes theoretically.
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PURPOSE: In the event of a large-scale radiological accident, rapid and high-throughput biodosimetry is the most vital basis in medical resource allocation for the prompt treatment of victims. However, the current biodosimeter is yet to be rapid and high-throughput. Studies have shown that ionizing radiation modulates expressions of circular RNAs (circRNAs) in healthy human cell lines and tumor tissue. circRNA expressions can be quantified rapidly and high-throughput. However, whether circRNAs are suitable for early radiation dose classification remains unclear. METHODS: We employed transcriptome sequencing and bioinformatics analysis to screen for radiation-differentially expressed circRNAs in the human lymphoblastoid cell line AHH-1 at 4 h following exposure to 0, 2, and 5 Gy 60Co γ-rays. The dose-response relationships between differentially expressed circRNA expressions and absorbed doses were investigated using real-time polymerase chain reaction and linear regression analysis at 4 h, 24 h, and 48 h post-exposure to 0, 2, 4, 6, and 8 Gy. Six distinct dose classification models of circRNA panels were established and validated by receiver operating characteristic (ROC) curve analysis. RESULTS: A total of 11 radiation-differentially expressed circRNAs were identified and validated. Based on dose-response effects, those circRNAs changed in a dose-responsive or dose-dependent manner were combined into panels A through F at 4 h, 24 h, and 48 h post-irradiation. ROC curve analysis showed that panels A through C had the potential to effectively classify exposed and non-exposed conditions, which area under the curve (AUC) of these three panels were all 1.000, and the associate p values were .009. Panels D through F excellently distinguished between different dose groups (AUC = 0.963-1.000, p < .05). The validation assay showed that panels A through F demonstrated consistent excellence in sensitivity and specificity in dose classification. CONCLUSIONS: Ionizing radiation can indeed modulate the circRNA expression profile in the human lymphoblastoid cell line AHH-1. The differentially expressed circRNAs exhibit the potential for rapid and high-throughput dose classification.
Subject(s)
RNA, Circular , RNA , Humans , RNA, Circular/genetics , RNA/genetics , RNA/metabolism , ROC Curve , Sensitivity and Specificity , Cell LineABSTRACT
Designing a functional, conductive metal-organic framework (cMOF) is highly desired. Substantial efforts have been dedicated to increasing the intralayer conjugation of the cMOFs, while less dedication has been made to tuning the interlayer charge transport of the metal-organic nanosheets for the controllable dielectric property. Here, we construct a series of conductive bimetallic organic frameworks of (ZnxCu3-x) (hexahydroxytriphenylene)2 (ZnCu-HHTP) to allow for fine-tuned interlayer spacing of two-dimensional frameworks, by adjusting the ratios of Zn and Cu metal ions. This approach for atomistic interlayer design allows for the finely control of the charge transport, band structure, and dielectric properties of the cMOF. As a result, Zn3Cu1-HHTP, with an optimal dielectric property, exhibits high-efficiency absorption in the gigahertz microwave range, achieving an ultra-strong reflection loss of -81.62 decibels. This study not only advances the understanding of the microstructure-function relationships in cMOFs but also offers a generic nanotechnology-based approach to achieving controllable interlayer spacing in MOFs for the targeted applications.
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Genetic elements of interest can be introduced into the Saccharomyces cerevisiae genome via homologous recombination. The current method is to link such an element to a selectable marker gene to be integrated into the target locus. However, the marker gene in this method cannot be reused, which limits repeated manipulation of the yeast genome. An alternative method is to utilize a counterselectable gene, such as URA3, with flanking tandem repeats. After integration, URA3 along with one copy of the repeat can be popped out via internal recombination, leaving behind one copy of the unwanted repeat. Here we describe a novel concept of genetic element shuffling in which the tandem repeats are made of the desired genetic element, so that after integration and popping out, only one copy of the element remains at the desired locus to function. As a proof of principle, we constructed three recyclable cassettes (PPGK1-URA3-PPGK1, PGAL1-URA3-PGAL1, and PtetO7-URA3-PtetO7) and integrated them upstream of an engineered chromosomal PHIS3-mCherry-Myc locus. After promoter shuffling, the mCherry-Myc gene was regulated precisely as anticipated.
Subject(s)
Gene Expression Regulation, Fungal , Genetic Engineering/methods , Promoter Regions, Genetic , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/isolation & purification , DNA, Fungal/genetics , Genes, Fungal , Genes, Reporter , Genetic Loci , Genetic Markers , Microscopy, Fluorescence , Plasmids/genetics , Recombination, Genetic , Sequence Analysis, DNAABSTRACT
In the crystal structure of the title compound, C13H7N3O·H2O, the components are associated into chains along [010] through strong O-Hâ¯O hydrogen bonds with the free water mol-ecules as bridging ligands. These chains are further cross-linked by C-Hâ¯O and C-Hâ¯N hydrogen bonds, forming a three-dimensional structure.
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To provide the basis for thermal conductivity regulation of vermicular graphite cast iron (VGI), a new theoretical method consisting of shape interpolation, unit cell model and numerical calculation was proposed. Considering the influence of the graphite anisotropy and interfacial contact thermal conductivity (ICTC), the effective thermal conductivity of a series of unit cell models was calculated by numerical calculation based on finite difference. The effects of microstructure on effective thermal conductivity of VGI were studied by shape interpolation. The experimental results were in good agreement with the calculated ones. The effective thermal conductivity of VGI increases in power function with the decrease in graphite shape parameter, and increases linearly with the increase in graphite volume fraction and thermal conductivity of matrix. When the graphite volume fraction increases by 1%, the thermal conductivity of nodular cast iron increases by about 0.18 W/(m·K), while that of gray cast iron increases by about 3 W/(m·K). The thermal conductivity of cast iron has the same sensitivity to the thermal conductivity of matrix regardless of the graphite shape parameter. The thermal conductivity of matrix increased by 15 W/(m·K) and the thermal conductivity of cast iron increased by about 12 W/(m·K). Moreover, the more the graphite shape deviates from the sphere, the greater the enhancement effect of graphite anisotropy on thermal conductivity than the hindrance effect of interface between graphite and matrix. This work can provide guidance for the development of high thermal conductivity VGI and the study of thermal conductivity of composites containing anisotropic dispersed phase particles with complex shapes.
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Enterotoxigenic Escherichia coli (ETEC) is a common pathogen of swine colibacillosis, which can causing a variety of diseases initiate serious economic losses to the animal husbandry industry. The traditional Chinese medicine Changyanning (CYN) often used for diarrhea caused by the accumulation of damp heat in the gastrointestinal tract, has anti-bacterial, anti-inflammatory and anti-oxidation effects. This study investigated the effect of CYN on gut microbiota and metabolism in mice infected with ETEC K88. A total of 60 Kunming mices were divided into Control group, ETEC K88 group, CYN.L group (2.5 g/kg), CYN.M group (5 g/kg), CYN.H group (10 g/kg) and BTW group (10 g/kg), determined clinical symptoms, intestinal morphology, inflammatory responses, gut microbiota as well as serum metabolites. CYN administration elevated ETEC K88-induced body weight loss, ameliorated duodenum, ilem, colon pathological injury, and reduced the increase of spleen index caused by ETEC. CYN also reduced the levels of pro-inflammatory cytokines (IL-6, TNE-α) in the serum. 16s rRNA gene sequencing results showed that CYN increased the abundance of beneficial bacteria Lactobacillus but decreased the abundance of pathogenic bacteria Escherichia in the feces of mice. Moreover, CYN participates in amino acid biosynthesis and metabolism in the process of serum metabolism to regulates ameliorate intestinal injury induced by ETEC K88. In conclusion, CYN regulates gut microbiota and metabolism to ameliorate intestinal injury induced by ETEC K88.