The metal-support interactions (MSI) could greatly determine the electronic properties of single-atom catalysts, thus affecting the catalytic performance. However, the typical approach to regulating ...MSI usually suffers from interference of the variation of supports or sacrificing the stability of catalysts. Here, we effectively regulate the site-specific MSI of Ir single atoms anchored on Ni layered double hydroxide through an electrochemical deposition strategy. Cathodic deposition drives Ir atoms to locate at three-fold facial center cubic hollow sites with strong MSI, while anodic deposition drives Ir atoms to deposit onto oxygen vacancy sites with weak MSI. The mass activity and intrinsic activity of Ir single-atom catalysts with strong MSI towards oxygen evolution reaction are 19.5 and 5.2 times that with weak MSI, respectively. Mechanism study reveals that the strong MSI between Ir atoms and the support stimulates the activity of Ir sites by inducing the switch of active sites from Ni sites to Ir sites and optimizes the adsorption strength of intermediates, thereby enhancing the activity.
•Stepwise pyrolysis of the asphaltene from the Maoming oil shale carried out.•Range of functionalized lipids indicative of low thermal maturity found.•Sterols, stenones and steradienes were dominated ...by C29 homologues.•Both microalgae and land plants are significant sources of organic matter.•Asphaltene preserves biomarkers that can be liberated via stepwise pyrolysis.
Eocene Maoming oil shale was extracted and the precipitated asphaltene was subjected to stepwise pyrolysis carried out in seven temperature steps from 310°C to 610°C at 50°C intervals. The pyrolyzate at 310°C included n-alkanes and botryococcanes in a distribution similar to the extractable lipids. Long chain n-alkanols, fatty acids (FAs) and C29 steroids were also relatively abundant. The pyrolyzate released at 360°C was comparable with that at 310°C, but had a relatively high content of a steradiene (C29 Δ3,5-steradiene) and several C29 unsaturated steroid ketones derived from the pyrolysis of sterols by loss of –OH and –H. FAs were not present in the pyrolyzate at 410°C. Among the steroid ketones, the diones made a greater contribution, indicating that these ketones were formed as secondary products during the pyrolysis. A full suite of aliphatic hydrocarbons made its first appearance at 460°C, but steroid ketones still dominated the pyrogram. Prist-1-ene, which is frequently detected in the pyrolysis of geological macromolecules, was only a minor component, as were four unknown isomers tentatively labelled as monounsaturated C15 isoprenoid ketones. The pyrolyzates at 510 and 560°C were dominated by n-alkene/n-alkane doublets which had a bimodal distribution and carbon numbers up to C37 (at 510°C). Only trace amounts of n-alkene/n-alkane doublets were produced from the 610°C pyrolysis step. The results show that stepwise pyrolysis can be a fast overview tool for studying components of the asphaltene fraction and can provide useful information on the sources of organic matter (OM) in the oil shale, including polar molecules such as sterols, ketones, and fatty acids. An obvious advantage is the avoidance of complicated pre-treatments before detection using gas chromatography-mass spectrometry (GC–MS). The data confirm the importance of algal OM in the Maoming oil shale as well as the terrigenous plant contribution.
Nanocarriers with positive surface charges are known for their toxicity which has limited their clinical appli- cations. The mechanism underlying their toxicity, such as the induction of inflammatory ...response, remains largely unknown. In the present study we found that injection of cationic nanocarriers, including cationic liposomes, PEI, and chitosan, led to the rapid appearance of necrotic cells. Cell necrosis induced by cationic nanocarriers is dependent on their positive surface charges, but does not require RIP1 and Mlkl. Instead, intracellular Na^＋ overload was found to accompany the cell death. Depletion of Na^＋ in culture medium or pretreatment of cells with the Na^＋/K^＋- ATPase cation-binding site inhibitor ouabain, protected cells from cell necrosis. Moreover, treatment with cationic nanocarriers inhibited Na^＋/K^＋-ATPase activity both in vitro and in vivo. The computational simulation showed that cationic carriers could interact with cation-binding site of Na^＋/K^＋-ATPase. Mice pretreated with a small dose of ouabain showed improved survival after injection of a lethal dose of cationic nanocarriers. Further analyses suggest that cell necrosis induced by cationic nanocarriers and the resulting leakage of mitochondrial DNA could trigger severe inflammation in vivo, which is mediated by a pathway involving TLR9 and MyD88 signaling. Taken together, our results reveal a novel mechanism whereby cationic nanocarriers induce acute cell necrosis through the interaction with Na^＋/K^＋-ATPase, with the subsequent exposure of mitochondrial damage-associated molecular patterns as a key event that mediates the inflammatory responses. Our study has important implications for evaluating the biocompatibility of nanocarriers and designing better and safer ones for drug delivery.
As a valuable medicinal plant, Rhodiola has a very long history of folk medicine used as an important adaptogen, tonic, and hemostatic. However, our knowledge of the chloroplast genome level of ...Rhodiola is limited. This drawback has limited studies on the identification, evolution, genetic diversity and other relevant studies on Rhodiola. Six Rhodiola complete chloroplast genomes were determined and compared to another Rhodiola cp genome at the genome scale. The results revealed a cp genome with a typical quadripartite and circular structure that ranged in size from 150,771 to 151,891 base pairs. High similarity of genome organization, gene number, gene order, and GC content were found among the chloroplast genomes of Rhodiola. 186 (R. wallichiana) to 200 (R. gelida) SSRs and 144 pairs of repeats were detected in the 6 Rhodiola cp genomes. Thirteen mutational hotspots for genome divergence were determined and could be used as candidate markers for phylogenetic analyses and Rhodiola species identification. The phylogenetic relationships inferred by members of Rhodiola cluster into two clades: dioecious and hermaphrodite. Our findings are helpful for understanding Rhodiola's taxonomic, phylogenetic, and evolutionary relationships. Comparative analysis of chloroplast genomes of Rhodiola facilitates medicinal resource conservation, phylogenetic reconstruction and biogeographical research of Rhodiola.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Hepatic fibrosis is one kind of liver diseases with a high mortality rate and incidence. The activation and proliferation of hepatic stellate cells (HSCs) is the most fundamental reason of hepatic ...fibrosis. There are no specific and effective drug delivery carriers for the treatment of hepatic fibrosis at present. We found that when hepatic fibrosis occurs, the expression of CD44 receptors on the surface of HSCs is significantly increased. Based on this finding, we designed silibinin-loaded hyaluronic acid (SLB-HA) micelles to achieve the treatment of hepatic fibrosis. Meanwhile, we constructed liver fibrosis rat model using Sprague–Dawley rats. We demonstrated that HA micelles had specific uptake to HSCs in vitro while avoiding the distribution in normal liver cells and the phagocytosis of macrophages. Importantly, HA micelles showed a significant liver targeting effect in vivo, especially in fibrotic liver which highly expressed CD44 receptors. In addition, SLB-HA micelles could selectively kill activated HSCs, having an excellent anti-hepatic fibrosis effect in vivo and a significant sustained release effect, and also had a good biological safety and biocompatibility. Overall, HA micelles represented a novel nanomicelle system which showed great potentiality in anti-hepatic fibrosis drugs delivery.
The silibinin-loaded hyaluronic acid (SLB-HA) micelles were designed to achieve the treatment of hepatic fibrosis. The HA micelles had specific uptake to hepatic stellate cells in vitro and in vivo, while avoiding the distribution in other liver cells and the phagocytosis of macrophages. Display omitted
The research and application of CO2 storage and enhanced oil recovery (EOR) have gradually emerged in China. However, the vast unconventional oil and gas resources are stored in reservoir pores ...ranging from several nanometers to several hundred micrometers in size. Additionally, CO2 geological sequestration involves the migration of fluids in tight caprock and target layers, which directly alters the transport and phase behavior of reservoir fluids at different scales. Micro- and nanoscale fluidics technology, with their advantages of in situ visualization, high temperature and pressure resistance, and rapid response, have become a new technical approach to investigate gas–liquid interactions in confined domains and an effective supplement to traditional core displacement experiments. The research progress of micro–nano fluidics visualization technology in various aspects, such as CO2 capture, utilization, and storage, is summarized in this paper, and the future development trends and research directions of micro–nano fluidics technology in the field of carbon capture, utilization, and storage (CCUS) are predicted.
Abstract
Biological membranes often play important functional roles in biomimetic drug delivery systems. We discover that the circulation time and targeting capability of biological membrane coated ...nanovehicles can be significantly improved by reducing cholesterol level in the coating membrane. A proof-of-concept system using cholesterol-reduced and PD-1-overexpressed T cell membrane to deliver a photothermal agent and a STING agonist is thus fabricated. Comparing with normal membrane, this engineered membrane increases tumor accumulation by ~2-fold. In a melanoma model in male mice, tumors are eliminated with no recurrence in >80% mice after intravenous injection and laser irradiation; while in a colon cancer model in male mice, ~40% mice are cured without laser irradiation. Data suggest that the engineered membranes escape immune surveillance to avoid blood clearance while keeping functional surface molecules exposed. In summary, we develop a simple, effective, safe and widely-applicable biological membrane modification strategy. This “subtractive” strategy displays some advantages and is worth further development.
In this study, a method for double-beam quantum cascade laser absorption spectroscopy (DB-QCLAS) was developed. Two mid-infrared distributed feedback quantum cascade laser beams were coupled in an ...optical cavity for the monitoring of NO and NO
(NO at 5.26 μm; NO
at 6.13 μm). Appropriate lines in the absorption spectra were selected, and the influence of common gases in the atmosphere, such as H
O and CO
, was avoided. By analyzing the spectral lines under different pressure conditions, the appropriate measurement pressure of 111 mbar was selected. Under this pressure, the interference between adjacent spectral lines could be effectively distinguished. The experimental results show that the standard deviations for NO and NO
were 1.57 ppm and 2.67 ppm, respectively. Moreover, in order to improve the feasibility of this technology for detecting chemical reactions between NO and O
, the standard gases of NO and O
were used to fill the cavity. A chemical reaction instantaneously began, and the concentrations of the two gases were immediately changed. Through this experiment, we hope to develop new ideas for the accurate and rapid analysis of the process of NOx conversion and to lay a foundation for a deeper understanding of the chemical changes in atmospheric environments.
Abstract
NLRP3 controls the secretion of inflammatory cytokines IL-1β/18 and pyroptosis by assembling the inflammasome. Upon coordinated priming and activation stimuli, NLRP3 recruits NEK7 within ...hetero-oligomers that nucleate ASC and caspase-1 filaments, but the apical molecular mechanisms underlying inflammasome assembly remain elusive. Here we show that NEK7 recruitment to NLRP3 is controlled by the phosphorylation status of NLRP3 S803 located within the interaction surface, in which NLRP3 S803 is phosphorylated upon priming and later dephosphorylated upon activation. Phosphomimetic substitutions of S803 abolish NEK7 recruitment and inflammasome activity in macrophages in vitro and in vivo. In addition, NLRP3-NEK7 binding is also essential for NLRP3 deubiquitination by BRCC3 and subsequently inflammasome assembly, with NLRP3 phosphomimetic mutants showing enhanced ubiquitination and degradation than wildtype NLRP3. Finally, we identify CSNK1A1 as the kinase targeting NLRP3 S803. Our findings thus reveal NLRP3 S803 phosphorylation status as a druggable apical molecular mechanism controlling inflammasome assembly.
Mountains have not only provided refuge for species, but also offered dispersal corridors during the Neogene and Quaternary global climate changes. Compared with a plethora of studies on the refuge ...role of China's mountain ranges, their dispersal corridor role has received little attention in plant phylogeographic studies. Using phylogeographic data of Eomecon chionantha Hance (Papaveraceae), this study explicitly tested whether the Nanling Mountains, which spans from west to east for more than 1000 km in subtropical China, could have functioned as a dispersal corridor during the late Quaternary in addition to a glacial refugium.
Our analyses revealed a range-wide lack of phylogeographic structure in E. chionantha across three kinds of molecular markers two chloroplast intergenic spacers, nuclear ribosomal internal transcribed spacer (nrITS), and six nuclear microsatellite loci. Demographic inferences based on chloroplast and nrITS sequences indicated that E. chionantha could have experienced a strong postglacial range expansion between 6000 and 1000 years ago. Species distribution modelling showed that the Nanling Mountains and the eastern Yungui Plateau were the glacial refugia of E. chionantha. Reconstruction of dispersal corridors indicated that the Nanling Mountains also have acted as a corridor of population connectivity for E. chionantha during the late Quaternary.
Our results suggest that the Nanling Mountains may acted dual roles as a dispersal corridor in east-west direction and as a glacial refugium in subtropical China during the late Quaternary. The population connectivity mediated by the mountain range and a strong postglacial range expansion are the most likely reasons for the lack of phylogeographic structure in E. chionantha. The hypothesis of dual roles of the mountain range presented here sheds new insights into the phylogeographic patterns of organisms in subtropical China.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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