Ceramic biomaterials have been investigated for several decades, but their potential biomedical applications in cancer therapy have been paid much less attentions, mainly due to their lack of related ...material functionality for combating the cancer. In this work, we report, for the first time, that MAX ceramic biomaterials exhibit the unique functionality for the photothermal ablation of cancer upon being exfoliated into ultrathin nanosheets within atomic thickness (MXene). As a paradigm, biocompatible Ti3C2 nanosheets (MXenes) were successfully synthesized based on a two-step exfoliation strategy of MAX phase Ti3AlC2 by the combined HF etching and TPAOH intercalation. Especially, the high photothermal-conversion efficiency and in vitro/in vivo photothermal ablation of tumor of Ti3C2 nanosheets (MXenes) were revealed and demonstrated, not only in the intravenous administration of soybean phospholipid modified Ti3C2 nanosheets but also in the localized intratumoral implantation of a phase-changeable PLGA/Ti3C2 organic–inorganic hybrid. This work promises the great potential of Ti3C2 nanosheets (MXenes) as a novel ceramic photothermal agent used for cancer therapy and may arouse much interest in exploring MXene-based ceramic biomaterials to benefit the biomedical applications.
We present RaGOO, a reference-guided contig ordering and orienting tool that leverages the speed and sensitivity of Minimap2 to accurately achieve chromosome-scale assemblies in minutes. After the ...pseudomolecules are constructed, RaGOO identifies structural variants, including those spanning sequencing gaps. We show that RaGOO accurately orders and orients 3 de novo tomato genome assemblies, including the widely used M82 reference cultivar. We then demonstrate the scalability and utility of RaGOO with a pan-genome analysis of 103 Arabidopsis thaliana accessions by examining the structural variants detected in the newly assembled pseudomolecules. RaGOO is available open source at https://github.com/malonge/RaGOO .
The response mechanism of aerobic granular sludge (AGS) systems to salt stress in high-salinity wastewater treatment processes has not been fully elucidated in current studies. The aim of this study ...was to reveal the comprehensive effects of salinity on AGS characteristics using microbial community and metaproteomics analyses. The results showed that the removal efficiency of COD, TN and TP decreased significantly with increasing salinity. Under salt stress, the Na+ content in AGS decreased, while the K+ and Ca2+ contents increased. This was because the salt-tolerant mechanism of the microorganisms was dependent on the uptake of K+ and ejection of Na+via K+/Na+ pumps, Na+/H+ reversed transport proteins, and K+ channels. Compared with the salt-free condition, 14 of 25 different protein spots were identified successfully by metaproteomic analysis, including porin, periplasmic-binding protein, and ATP-binding cassette-type for phosphonate transporter, which were expressed mainly by members of γ-Proteobacteria and α-Proteobacteria. The variations in functional proteins and microbial community revealed that α- and γ-Proteobacteria had disproportionally active and the metabolic activity of β-Proteobacteria was inhibited by increasing salinity. Additionally, Psychrobacter sp. was confirmed to be a predominant bacterium at 15 g/L NaCl, as the porin was strongly expressed.
•Functional proteins in aerobic granule sludge were tested under different salinity.•Reactor performance, granular characteristics and microbial community were monitored.•Psychrobacter sp. was predominant bacteria with plentiful porin expression at high salinity.•The metabolic activity of β-Proteobacteria was inhibited by the increasing salinity.•Porin, periplasmic-binding protein played an important role in high-salt tolerance.
Advancing crop genomics requires efficient genetic systems enabled by high-quality personalized genome assemblies. Here, we introduce RagTag, a toolset for automating assembly scaffolding and ...patching, and we establish chromosome-scale reference genomes for the widely used tomato genotype M82 along with Sweet-100, a new rapid-cycling genotype that we developed to accelerate functional genomics and genome editing in tomato. This work outlines strategies to rapidly expand genetic systems and genomic resources in other plant species.
•The initial strain and the shear modulus are revealed with moisture contents.•A method for obtaining the long-term strength of loess specimens is proposed.•A modified Burgers creep models is ...proposed.
Understanding the creeping behavior of loess is of great importance as large-scale loess landslides are closely related with creep behavior. At present, it is still challenging to predict and estimate the long-term stability of such landslides. This is in a large degree due to the poor understanding of moisture control on creep behavior of loess. The purpose of this study is to decipher the loess creep behavior under various moisture contents (MCs) using loess specimens obtained from Baqiao landslide, Xi’an of China, using multi-loading triaxial creep tests under different MCs of 9%, 12%, 15%, 18% and 21%. Based on the laboratory test results, a series of relationships between the creep rate at the steady-state creep stage and the initial strain and initial shear modulus are revealed. Meanwhile, a method for obtaining the long-term strength of loess specimens, namely, the Steady-state Creep Rate Slope Method (SCRSM), is proposed. SCRSM resolves the issue in several conventional methods such as the Isochronous Stress-Strain Curve Method, the Tangent Method of Steady Creep Rate when MCs are of concern. Such an improvement is primarily due to a better way of finding the inflection point of the steady-state rate. It is found that SCRSM is robust and accurate to determine the long-term strength of loess specimens. Furthermore, we propose a modified Burgers model with a newly introduced nonlinear parameter n to overcome deficiencies of conventional creep models. This modified Burgers model is flexible to fit the creep test curves of loess, and can describe the curves at the accelerated creep stage more accurately. Lastly, the main factors triggering the Baqiao landslide is analyzed considering stratum lithology, rainfall and excavation. In general, this study provides a basis for understanding the evolutional process of loess landslides as well as guidelines for prevention, controlling and prediction of loess landslides.
Treatment of full-thickness skin defects poses significant clinical challenges including risk of infection and severe scaring. Silver nanoparticle (NAg), an effective antimicrobial agent, has ...provided a promising therapeutic method for burn wounds. However, the detailed mechanism remains unknown. Hence, we constructed a metallic nanosilver particles-collagen/chitosan hybrid scaffold (NAg-CCS) and investigated its potential effects on wound healing. In vitro scratch assay, immunofluorescence staining and antibacterial activity of the scaffold were all studied. In vivo NAg-CCS was applied in full-thickness skin defects in Sprague-Dawley (SD) rats and the therapeutic effects of treatment were evaluated. The results showed that NAg at a concentration of 10 ppm accelerated the migration of fibroblasts with an increase in expression of α-smooth muscle actin (α-SMA). Furthermore, in vivo studies showed increased levels of pro-inflammatory and scar-related factors as well as α-SMA, while markers for macrophage activation were up-regulated. On day 60 post transplantation of ultra-thin skin graft, the regenerated skin by NAg-CCS had a similar structure to normal skin. In summary, we demonstrated that NAg-CCS was bactericidal, anti-inflammatory and promoted wound healing potentially by regulating fibroblast migration and macrophage activation, making it an ideal dermal substitute for wound regeneration.
In this study, we characterize and consider the effects of slope length and slope gradient on the size distributions of loess slides. To carry out this study, we employ data on 275 loess slides ...within Zhidan County, Central Loess Plateau, China. These data were collected in the field and supplemented by the interpretation of remote sensing images. Both the field observations and slope stability analysis show that loess slide size increases with the slope length. Slide sizes is significantly correlated with slope length, showing a power law relationship in both cases. However, the simulation results show that slope gradient is not associated with loess slide size. The main part of the link between slope gradient and slide size seen in the observations is only apparent, as indicated by the strong connection between slope gradient and length. Statistical analysis of the field observations reveals that slope gradient decreases with increasing slope length, and this correlation interferes with the potential relationship between landslide sizes and slope gradient seen in the field observations. In addition, the probability densities of the areas of loess slides occurring on slopes of different slope lengths are determined using kernel density estimation. This analysis shows that slope length controls the rollover of the frequency-size distribution of loess slides. The scaling exponent increases with slope length.
•Field observations and simulations of loess landslide size distribution•The size of loess landslides is controlled by the slope height and slope gradient.•The loess slide size increases with the slope height, whereas it decreases with the increase of slope gradient.•The slope height and slope gradient control the rollover of frequency-size distribution of loess slides.
As sessile organisms, plants must adapt to variations in the environment. Environmental stress triggers various responses, including growth inhibition, mediated by the plant hormone abscisic acid ...(ABA). The mechanisms that integrate stress responses with growth are poorly understood. Here, we discovered that the Target of Rapamycin (TOR) kinase phosphorylates PYL ABA receptors at a conserved serine residue to prevent activation of the stress response in unstressed plants. This phosphorylation disrupts PYL association with ABA and with PP2C phosphatase effectors, leading to inactivation of SnRK2 kinases. Under stress, ABA-activated SnRK2s phosphorylate Raptor, a component of the TOR complex, triggering TOR complex dissociation and inhibition. Thus, TOR signaling represses ABA signaling and stress responses in unstressed conditions, whereas ABA signaling represses TOR signaling and growth during times of stress. Plants utilize this conserved phospho-regulatory feedback mechanism to optimize the balance of growth and stress responses.
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•The TOR kinase phosphorylates ABA receptor PYLs at a conserved serine residue•PYLs phosphorylation inhibits stress responses by abolishing PYLs activities•Stress- and ABA-activated SnRK2s phosphorylate Raptor and inhibit TOR activity•TOR and ABA signaling balance plant growth and stress responses
Wang et al. reveal that the TOR kinase phosphorylates ABA receptors to repress stress responses under unstressed conditions and to promote growth recovery once environmental stresses subside. Under stress conditions, SnRK2s phosphorylate Raptor, a regulatory component in the TOR complex, to prevent growth by inhibiting TOR activity.
Affected by groundwater fluctuations, the loess around the hydro-fluctuation zone near the groundwater table is frequently subjected to periodic dry-wet cycles. The investigation on the creep ...characteristics and microstructural evolution associated with the mechanical response of loess after the application of dry-wet cyclings is of great significance to better understand the loess landslide mechanism. Triaxial creep tests and scanning electron microscopy (SEM) were conducted on intact loess specimens obtained from Heifangtai platform, Gansu, China. The micrographs were processed using IPP software and the microstructural information of soil pores were obtained. Results of triaxial creep test revealed that the application of dry-wet cyclings causes the creep deformation of loess soils to increase significantly, and they showed that the long-term strength and dry-wet cycle follow an exponentially decreasing function, indicating that the reduction in the long-term strength of loess soils is greater in the first five dry-wet cycling compared with that in the subsequently dry-wet cyclings. The microstructural analysis showed that aggregates were found to cluster upon the application of drying-wetting cycling, followed by the rearrangement of soil skeletons, transforming the initial relatively dense structure into a loosen one with a greater percentage of macro-pores which are more sensitive to creep deformation of loess soils. Additionally, it is observed that the microstructural evolution is dependent on the number of dry-wet cyclings. As the dry-wet cycles increase, the flatter and irregular macro-pores increased gradually at the expense of meso-pores. In addition, the mechanism of irrigation-induced loess landslides is revealed from the perspective of variation in creep characteristics of loess after the dry-wet cycles, which can be summarized into three stages, namely, the dry-wet cycle stage of the loess around the hydro-fluctuation zone; the long-term creep-liquefaction stage of the deep loess, and the slip surface transfixion stage.
•Reduction in qL is the greatest in the first five dry-wet cycling compared with that in the subsequently dry-wet cycling.•The microstructure of loess samples subjected to dry-wet cycling after yielding was investigated by SEM.•Flatter and irregular macro-pores increased gradually at the expense of meso-pores with an increase in the dry-wet cycling.
Extracellular matrix (ECM) derived from decellularized tissues and organs has been used as a biological scaffold in a variety of pre-clinical and clinical applications. However, the lack of ...mechanical properties and shape controllability is a drawback. In contrast, synthetic polymers can be easily engineered with good mechanical performance, but they have limited biological functionality. In this study, we explored a new method to electrospun cartilage-derived extracellular matrix (cECM) and polycaprolactone (PCL) composite nanofibrous membranes. The cartilage is a compact tissue for which electrospinning is difficult. To overcome this problem, the cartilage was sliced into pieces, milled into powders, and digested into a looser structure. The cECM/PCL (mass ratio 50:50) hybrid nanofibers appeared to be smooth, thinner, and uniform with enhanced mechanical properties and wettability compared to the electrospun PCL. Meanwhile, the presence of cECM in the cECM/PCL nanofibrous membranes significantly promoted chondrocyte proliferation in vitro and facilitated cartilage regeneration in vivo. All these results indicate that the cECM/PCL nanofibrous membranes fabricated with good mechanical properties and biocompatibility may represent a promising scaffold for cartilage regeneration. Moreover, this work may offer a convenient and cost-effective method to synthesize ECM-based hybrid nanofibrous scaffolds for other tissue applications.
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•A new method to electrospun cECM/PCL hybrid nanofibrous scaffold was explored.•The cECM/PCL scaffold have enhanced mechanical properties and superior wettability compared with PCL alone.•the cECM/PCL scaffold promoted chondrocyte proliferation in vitro and facilitated cartilage regeneration in vivo.•This method represents a platform in which different decellularized tissues could be electrospun into nanofibers.
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