Transmission electron microscope (TEM) imaging techniques combined with focused ion beam sample preparation were used to calibrate the solar energetic particle track production rate in lunar samples. ...Track density measurements by TEM as a function of depth were obtained from lunar rock 64455 that has a well‐constrained exposure age of 2 Myr giving a track production rate of 4.4 ± 0.4 × 104 tracks cm−2 yr−1 for a 2π exposure at 1 AU. The typical space weathering effects in mature lunar soils (both vapor‐deposited rims and solar wind‐damaged rims) accumulate in ˜106 yr based on the new calibration applied to track densities in individual grains. Solar wind‐damaged rim widths in anorthite and olivine follow a power law relationship with track density and achieve steady‐state widths in a few Myr. Vapor‐deposited rim widths show no correlation with exposure age suggesting that their formation is episodic with the full width of vapor‐deposited rims accumulating in a single or a few rare impact events. Solar wind‐damaged rim development was modeled using the stopping range of ions in matter code. Modeling shows that the solar wind‐damaged rims develop rapidly and approach steady‐state values in 105–106 yr. Anorthite and olivine record similar track densities for similar exposure ages, but their structural response to solar wind irradiation differs significantly. Solar wind‐damaged rims on olivine are not amorphous in contrast to modeling and high flux laboratory experiments and a model is proposed to account for their different response to solar wind irradiation.
The connotation, design optimization and implementation of the Volume Fracturing technique are discussed. The connotation includes five aspects as follows: (1) break up reservoirs to form complex ...fracture network, and “artificial” permeability; (2) the fracture initiation involving not only single open-fracture but shear failure and slip; (3) “breakthrough” the traditional fracturing seepage theory model, greatly shorten the effective fluid seepage distance; (4) more suitable for highly brittle formations; and (5) multi-stage and multi-cluster perforation mode to improve well productivity. Research shows that: the time required to seep through matrix with 0.000001 × 10−3 μm2 permeability to fracture for 100 m distance is about more than 100 × 104 years, and only Volume Fracturing can realize the “shortest distance”seepage. Cluster spacing optimization, non-uniform stage (cluster) interval and proppant filling mode are the key to achieve Volume Fracturing. Small cluster interval technology, multiple stop-injection construction mode and tip screen-out fracturing technology are the key techniques to realize Volume Fracturing in low brittle formations. Volume fracturing technique has a good application prospect in tight oil (gas), volcanic and carbonate reservoirs, and the further developed “integrated” volume fracturing (based on multi-layer and multi-branch well technology) is the future development direction for unconventional resources.
The poor electrochemical performance of LiMnPO4 nanoplates relative to that of isostructural LiFePO4 is clarified. LiMnPO4 nanoplates ca. 2 mm in diameter and 50 mm thick were prepared by a single ...solvothermal method. The 010 1D Li+ diffusion path lies in the plane of the platelets, and the two-phase LiMnPO4/MnPO4 interface intersects the 010 direction. A 10% volume change and a cooperative Jahn-Teller distortion of the Mn3+ sites in the MnPO4 phase introduces a large strain across the interface that impedes the rate of interface motion and therefore the rate of Li extraction/insertion. Nevertheless, a capacity of 107.5 mAh g−1 at the C/20 rate had a capacity fade of only 0.08% per cycle LiFePO4 platelets, on the other hand, have the 010 1D Li+ diffusion paths perpendicular to the platelets and the LiFePO4 interface parallel to the 010 direction, which leaves short diffusion lengths that are not blocked by structural changes.
► Synthesis and orientation of LiMnPO4 nanoplatelets. ► Orientation of MnPO4/LiMnPO4 two-phase interface versus ID Li-diffusion channels. ► Strain across and mobility of the MnPO4/LiMnPO4 two-phase boundary in Li1−xMnPO4.
Activation of nucleotide-binding domain leucine-rich repeat containing family pyrin domain containing 3 (NLRP3) inflammasome in Kupffer cells (KCs) contributes significantly to hepatic ...ischemia/reperfusion (I/R) injury, while the mechanism of how NLRP3 inflammasome is regulated remains less well defined. Recent evidence has showed that mitophagy acts as a central player for maintaining mitochondrial homeostatis through elimination of damaged mitochondria, leading to the prevention of hyperinflammation triggered by NLRP3 activation. In this study, we aimed at investigating the potential role of PTEN-induced kinase 1 (PINK1)-mediated mitophagy in hepatic I/R injury. C57BL/6 mice subjected to partial warm hepatic I/R or primary KCs exposed to anoxia/reoxygenation (A/R) was used as in vivo or in vitro model, respectively. Mitophagy was measured by protein levels of PINK1, Parkin, LC3B-II, TOMM20 and p62. NLRP3, caspase-1 and IL-1β at mRNA and/or protein levels were used as indicators of inflammasome activation. Our results demonstrated remarkable hepatic inflammation and NLRP3 inflammasome activation during hepatic I/R, along with increased PINK1-mediated mitophagy. Notably, overexpression of PINK1 in vivo attenuated hepatic I/R injury, ROS production, NLRP3 activation and hepatic inflammation. In parallel, A/R challenge in vitro also triggered NLRP3 activation in KCs accompanied by increase in mitophagy. Enhanced mitophagy mediated by PINK1 overexpression further inhibited NLRP3 activation and reversed the KC-mediated inflammatory injury to hepatocytes. Kinase-dead mutation of PINK1 completely abolished the above protective effects by PINK1. Blocking of mitophagy/autophagy by silencing of PINK1/Parkin, ATG5, NDP52 or OPTN showed the totally opposite effects, respectively. Treatment with different autophagic inhibitors also consistently reversed the PINK1-mediated effects, suggesting that an intact PINK1-mediated mitophagy signaling was crucial for ablation of NLRP3 signaling in the presence of A/R. Together, these results support a critical role of PINK1-mediated mitophagy in mitochondrial quality control for KC activation and function in hepatic I/R.
Display omitted
•PINK1-mediated mitophagy restrained excessive mtROS production and mtDNA association with NLRP3 in the presence of I/R or A/R, thereby inhibiting NLRP3 inflammasome activation.•Blocking of mitophagyby silencing of PINK1/Parkin, ATG5, NDP52 or OPTN, or by treatment with 3-MA or CQ, consistently abolished the protective effects by PINK1, respectively.
We examined the presence of iron-oxidizing bacteria (IOB) at a groundwater surface water interface (GSI) impacted by reduced groundwater originating as leachate from an upgradient landfill. IOB ...enrichments and quantifications were obtained, at high vertical resolution, by an iron/oxygen opposing gradient cultivation method. The depth-resolved soil distribution profiles of water content, Fe²⁺, and total Fe indicated sharp gradients within the top 10 cm sediments of the GSI, where the IOB density was the highest. In addition, the vertical distribution of iron-reducing bacteria at the same sampling site mirrored the IOB distribution. Clone libraries from two separate IOB enrichments indicated a stratified IOB community with clear differences at short vertical distances. Alpha- and Betaproteobacteria were the dominant phylotypes. Clones from the near-surface sediment (1-2 cm below ground surface) were dominated by members of the Bradyrhizobiaceae and Comamonadaceae; clones from the deeper sediments were phylogenetically more diverse, dominated by members of the Rhodocyclaceae. The iron deposition profiles indicated that active iron oxidation occurred only within the near-to-surface GSI sediments. The match between the iron deposition profiles and the IOB abundance profiles strongly hints at the contribution of the IOB community to Fe oxidation in this Fe-rich GSI ecosystem.
Manganese (Mn) oxides are among the strongest mineral oxidants in the environment and impose significant influence on mobility and bioavailability of redox-active substances, such as arsenic, ...chromium, and pharmaceutical products, through oxidation processes. Oxidizing potentials of Mn oxides are determined by Mn valence states (2+, 3+, 4+). In this study, the effects of beam damage during electron energy-loss spectroscopy (EELS) in the transmission electron microscope have been investigated to determine the “safe dose” of electrons. Time series analyses determined the safe dose fluence (electrons/nm2) for todorokite (106 e/nm2), acid birnessite (105), triclinic birnessite (104), randomly stacked birnessite (103), and δ-MnO2 (<103) at 200 kV. The results show that meaningful estimates of the mean Mn valence can be acquired by EELS if proper care is taken.
Mineralogical studies of coatings on quartz grains and bulk sediments from an aquifer on Western Cape Cod, Massachusetts, USA were carried out using a variety of transmission electron microscopy ...(TEM) techniques. Previous studies demonstrated that coatings on quartz grains control the adsorption properties of these sediments. Samples for TEM characterization were made by a gentle mechanical grinding method and focused ion beam (FIB) milling. The former method can make abundant electron-transparent coating assemblages for comprehensive and quantitative X-ray analysis and the latter technique protects the coating texture from being destroyed. Characterization of the samples from both a pristine area and an area heavily impacted by wastewater discharge shows similar coating textures and chemical compositions. Major constituents of the coating include Al-substituted goethite and illite/chlorite clays. Goethite is aggregated into well-crystallized domains through oriented attachment resulting in increased porosity. Illite/chlorite clays with various chemical compositions were observed to be mixed with goethite aggregates and aligned sub-parallel to the associated quartz surface. The uniform spatial distribution of wastewater-derived phosphorus throughout the coating from the wastewater-contaminated site suggests that all of the coating constituents, including those adjacent to the quartz surface, are accessible to groundwater solutes. Both TEM characterization and chemical extraction results indicate there is a significantly greater amount of amorphous iron oxide in samples from wastewater discharge area compared to those from the pristine region, which might reflect the impact of redox cycling of iron under the wastewater-discharge area. Coating compositions are consistent with the moderate metal and oxy-metalloid adsorption capacities, low but significant cation exchange capacities, and control of iron(III) solubility by goethite observed in reactive transport experimental and modeling studies conducted at the site.
►A cross section of quartz sand coating was made by the FIB technique. ►Goethite and clay minerals are the main constituents of the coating. ►All of the coating constituents are accessible to groundwater solutes. ►Dissolution of goethite and precipitation of amorphous iron oxide. ►Vivianite-like iron phosphate was formed.
Display omitted
•A triarylnaphthvalene was synthesized by photoinduced valence isomerization reaction.•The single crystal structure of the triarylnaphthvalene was determined.•The triarylnaphthvalene ...is stable at room temperature.•The triarylnaphthvalene decomposes to form two triarylnaphthalenes upon heating.
2-Phenyl-1,3-di(4-pyridyl)naphthvalene 3a was synthesized by the photoinduced reversible valence isomerization of 2-phenyl-1,3-di(4-pyridyl)naphthalene 2a. Then, 3a was converted into 3-phenyl-1,2-di(4-pyridyl)naphthalene 4a and 2a simultaneously. The t1/2 of 3a in DMSO-d6 at 90 °C was 2 h, while that at 110 °C was approximately 10 min.
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal).
This article has been retracted at the ...request of the Editor-in-Chief and authors.
Following the publication of the above article, the Editor was notified by a concerned reader that the authors supplied duplicated images. Specifically, that in Fig. 5 A, both FACS panels are identical and in Fig 5E, two different proteins (HK2 and PDK1) have the same western blot.
After checking the data in relation with Fig. 5A and E, the authors have confirmed that the two pictures indeed have the problems of duplication. The authors reported that this problem came from the authors’ unintentional behavior, which may be due to a copy and paste error in the manner of image processing. The authors sincerely apologize for the inconvenience caused to our Editors and readers.
Due to this duplication error, the authors and Editor have made the decision to retract this paper.
Hepatic ischemia/reperfusion (I/R) contributes to major complications in clinical practice affecting perioperative morbidity and mortality. Recent evidence suggests the key role of nucleotide-binding ...oligomerization domain-like receptor (NLR) family pyrin domain-containing 3 (NLRP3) inflammaosme activation on the pathogenesis of I/R injury. Asiatic acid (AA) is a pentacyclic triterpene derivative presented with versatile activities, including antioxidant, anti-inflammation and hepatoprotective effects. This study was designed to determine whether AA had potential hepatoprotective benefits against hepatic I/R injury, as well as to unveil the underlying mechanisms involved in the putative effects. Mice subjected to warm hepatic I/R, and Kupffer cells (KCs) or RAW264.7 cells challenged with lipopolysaccharide (LPS)/H
O
, were pretreated with AA. Administration of AA significantly attenuated hepatic histopathological damage, global inflammatory level, apoptotic signaling level, as well as NLRP3 inflammasome activation. These effects were correlated with increased expression of peroxisome proliferator-activated receptor gamma (PPARγ). Conversely, pharmacological inhibition of PPARγ by GW9662 abolished the protective effects of AA on hepatic I/R injury and in turn aggravated NLRP3 inflammasome activation. Activation of NLRP3 inflammasome was most significant in nonparenchymal cells (NPCs). Depletion of KCs by gadolinium chloride (GdCl3) further attenuated the detrimental effects of GW9662 on hepatic I/R as well as NLRP3 activation.
, AA concentration-dependently inhibited LPS/H
O
-induced NLRP3 inflammaosome activation in KCs and RAW264.7 cells. Either GW9662 or genetic knockdown of PPARγ abolished the AA-mediated inactivation of NLRP3 inflammasome. Mechanistically, AA attenuated I/R or LPS/H
O
-induced ROS production and phosphorylation level of JNK, p38 MAPK and IκBα but not ERK, a mechanism dependent on PPARγ. Finally, AA blocked the deleterious effects of LPS/H
O
-induced macrophage activation on hepatocyte viability
, and improved survival in a lethal hepatic I/R injury model
. Collectively, these data suggest that AA is effective in mitigating hepatic I/R injury through attenuation of KCs activation via PPARγ/NLRP3 inflammasome signaling pathway.
PDF
