Data-Driven Structure Recognition of Scanning Tunneling Microscopy Images in a Case of Iron Carbide.

Scanning tunneling microscopy (STM) serves as a critical tool for high-resolution surface imaging, yet deciphering the atomic structures from STM images on multielement surfaces, such as oxides and carbides, remains a challenging task that heavily relies on the expertise and intuition of researchers. In this study, we introduce a data-driven method for rapid structural recognition from STM images. This method involves extracting structural features, filtering through a structural database, and matching with simulated STM images and surface energy analyses, thereby providing researchers with several of the most probable structures. We demonstrate the capabilities of this technique using our previously reported iron carbide grown on an Fe(110) crystal. By proposing a candidate structure set and establishing a comprehensive database linking STM images to corresponding structures and surface energies, we selected 6 out of more than 10 000 possible surfaces. On the basis of these 6 recommendations, researchers can conveniently determine the real surface structures. Our work provides an efficient tool for the structure recognition of STM images to construct surface structures, potentially serving as a universal auxiliary tool for STM structural analysis.

Artificial intelligence-assisted system for the assessment of Forrest classification of peptic ulcer bleeding: a multicenter diagnostic study.

BACKGROUND: Inaccurate Forrest classification may significantly affect clinical outcomes, especially in high risk patients. Therefore, this study aimed to develop a real-time deep convolutional neural network (DCNN) system to assess the Forrest classification of peptic ulcer bleeding (PUB). METHODS: A training dataset (3868 endoscopic images) and an internal validation dataset (834 images) were retrospectively collected from the 900th Hospital, Fuzhou, China. In addition, 521 images collected from four other hospitals were used for external validation. Finally, 46 endoscopic videos were prospectively collected to assess the real-time diagnostic performance of the DCNN system, whose diagnostic performance was also prospectively compared with that of three senior and three junior endoscopists. RESULTS: The DCNN system had a satisfactory diagnostic performance in the assessment of Forrest classification, with an accuracy of 91.2% (95%CI 89.5%-92.6%) and a macro-average area under the receiver operating characteristic curve of 0.80 in the validation dataset. Moreover, the DCNN system could judge suspicious regions automatically using Forrest classification in real-time videos, with an accuracy of 92.0% (95%CI 80.8%-97.8%). The DCNN system showed more accurate and stable diagnostic performance than endoscopists in the prospective clinical comparison test. This system helped to slightly improve the diagnostic performance of senior endoscopists and considerably enhance that of junior endoscopists. CONCLUSION: The DCNN system for the assessment of the Forrest classification of PUB showed satisfactory diagnostic performance, which was slightly superior to that of senior endoscopists. It could therefore effectively assist junior endoscopists in making such diagnoses during gastroscopy.

Plasmonic Cu Nanoparticles for the Low-temperature Photo-driven Water-gas Shift Reaction.

The activation of water molecules in thermal catalysis typically requires high temperatures, representing an obstacle to catalyst development for the low-temperature water-gas shift reaction (WGSR). Plasmonic photocatalysis allows activation of water at low temperatures through the generation of light-induced hot electrons. Herein, we report a layered double hydroxide-derived copper catalyst (LD-Cu) with outstanding performance for the low-temperature photo-driven WGSR. LD-Cu offered a lower activation energy for WGSR to H2 under UV/Vis irradiation (1.4 W cm-2 ) compared to under dark conditions. Detailed experimental studies revealed that highly dispersed Cu nanoparticles created an abundance of hot electrons during light absorption, which promoted *H2 O dissociation and *H combination via a carboxyl pathway, leading to the efficient production of H2 . Results demonstrate the benefits of exploiting plasmonic phenomena in the development of photo-driven low-temperature WGSR catalysts.

Initial stage of carbonization of iron during hydrocarbons dissociation: a molecular dynamics study.

The carbonization of iron is a very important early phenomenon in the field of heterogeneous catalysis and the petrochemical industry, but the mechanism is still controversial. In this work, the carbonization mechanism and carbonization structure of iron nanoparticles by different carbon sources (CH4, C2H6, C2H4, C2H2) were systematically investigated using the reactive molecular dynamics method. The results show that saturated alkanes are dehydrogenated while adsorbed, but unsaturated olefins and alkynes undergo bond-breaking while adsorbed. The C-H bond is more likely to break than the C-C bond. Hydrocarbons with high carbon content have a strong ability to carbonize Fe nanoparticles under the same conditions. For C2H4 and C2H2, the C atoms generated from dissociation form a large number of long carbon chains intertwined with branched chains and multiple carbon rings. The C2 species formed by C2H2 after complete dehydrogenation diffuse rapidly to the interior of the nanoparticles, releasing the surface active sites and accelerating the carbonization process. Carbon-rich iron carbides (FeCx) with different Fe/C ratios were obtained by carbonization with different carbon sources. In addition, the Fe(110) surface exhibits the strongest carburizing ability. These findings provide systematic insights into the initial stages of metal Fe carburization.

Fibular osteotomy is helpful for talar reduction in the treatment of varus ankle osteoarthritis with supramalleolar osteotomy.

BACKGROUND: There have been debates on the necessity of fibular osteotomy (FO) in supramalleolar osteotomy (SMOT) for the treatment of varus ankle osteoarthritis. The purpose of the current study was to compare the clinical and radiological outcomes between SMOT with and without FO in the treatment of varus ankle osteoarthritis. METHODS: The SMOT group included 39 patients, and the SMOT with FO group included 24 patients. The basic information reached no significant difference between groups. The American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, Ankle Osteoarthritis Scale (AOS), modified Takakura stage and range of motion (ROM) were used for the functional evaluation. The radiologic parameters were assessed at the last follow-up to compare the degree of talar reduction between the two groups. RESULTS: Both groups achieved significant improvements in AOFAS scores, modified Takakura stage, as well as AOS pain and functional scores (P < 0.001). The ROM of the ankle joint in the SMOT group was significantly decreased (P = 0.022). In both groups, all of the radiological parameters were significantly improved (P < 0.01). The tibiofibular clear space (TFCS) was significantly widened in the SMOT group (P < 0.001). No significant difference was found between the two groups according to the functional outcomes. However, the talar tilt angle (TT) and hindfoot alignment angle (HFA) in the SMOT with FO group were significantly smaller than those in the SMOT group (P < 0.05). The TFCS was significantly widened in the SMOT group (P = 0.001). The medial displacement of the talus (MDT) was better reduced in the SMOT with FO group (P = 0.006). CONCLUSION: SMOT is a promising procedure for functional improvement and malalignment correction in varus ankle osteoarthritis but reduces ankle range of motion. If SMOT is combined with FO, talar tilt and medial displacement will be better reduced.

Ilizarov Gradual Distraction Correction for Distal Tibial Severe Varus Deformity Resulting from Epiphyseal Fracture: Case Report and Literature Review.

We present a case of a 13-year-old female with severe varus deformity and limb discrepancy resulting from epiphyseal fracture. The preoperative tibial articular surface angle was 64.1°, and the affected tibia was 14 mm shorter than the contralateral tibia. She underwent a medial open osteotomy and fibular osteotomy with gradual distraction correction using Ilizarov fixator. The deformity was corrected at 3 months, and the external fixator was removed when bony union was achieved 6 months postoperatively. At 9 months after surgery, the patient could play basketball without feeling pain. At the last follow-up, namely 36 months after the operation, the American Orthopaedic Foot and Ankle Society hindfoot-ankle score was improved from 58 to 90, the patient was pain free, and the radiological measurements were nearly normal. Ilizarov fixator gradual distraction correction for distal tibial severe varus deformity is a safe and cost-effective method that can yield excellent radiological and clinical outcomes.

Insight into the magnetic moment of iron borides: theoretical consideration from the local coordinative and electronic environment.

Experimentally observed magnetic properties are usually statistically averaged from bulk materials and information associated with the local chemical environment cannot be specified. Against this backdrop, we propose a theoretical strategy to provide an in-depth understanding of the multi-role for metrics that may contribute to the apparent magnetic moment of iron borides. In particular, we demonstrate this strategy through systematic manipulation of the iron/boron stoichiometry of six prototype iron borides to tune their associated local structural and electronic environment to further modulate the resultant magnetic moment. The local coordinative structures of the six iron borides were resolved utilizing bond valence analysis by taking the different coordination shells into account. Furthermore, the local electronic properties of each Fe atom in these iron borides, such as charge transfer, electronic distribution, bonding feature and orbital energy level, were carefully analyzed by Bader analysis, density of states analysis and Crystal Orbital Hamilton Population analysis. From the combination of analyses of both the coordinative and electronic properties of the prototype iron borides, a linear relationship between the local magnetic moment and the bond valence as well as the average energy of the Fe 3d orbitals has been confirmed.

Supramalleolar osteotomy with medial distraction arthroplasty for ankle osteoarthritis with talar tilt.

BACKGROUND: An increased preoperative talar tilt (TT) angle was reported to be positively correlated with treatment failure after supramalleolar osteotomy (SMOT) for varus ankle osteoarthritis. Distraction arthroplasty was reported to have the ability to correct increased TT angles. The purpose of the current study was to compare the outcomes between SMOT with and without medial distraction arthroplasty (MDA) in the treatment of varus ankle osteoarthritis with increased TT angles. METHODS: We retrospectively reviewed the functional outcomes and radiological findings of 34 patients who underwent SMOT with or without MDA for varus ankle osteoarthritis with increased TT angles. The American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score and Ankle Osteoarthritis Scale (AOS) scores were used for functional evaluation. The tibial anterior surface (TAS) angle, talar tilt (TT) angle, tibial medial malleolar (TMM) angle, talocrural (TC) angle, tibial lateral surface (TLS) angle, and hindfoot alignment (HFA) angle were evaluated preoperatively and at the time of the last follow-up. RESULTS: In the SMOT group, the AOFAS score and AOS pain and function scores were significantly improved (P < 0.01 for each) at a mean follow-up of 61 months. The TAS, TT, TC, TLS, and HFA angles were all significantly improved (P < 0.01 for each). Similarly, in the SMOT with MDA group, the AOFAS score, AOS pain and function scores, and the TAS, TT, TC, TLS, and HFA angles were all significantly improved postoperatively (P < 0.01 for each). When comparing the two groups, the postoperative TT angle was significantly smaller in the SMOT with MDA group (P = 0.023) than in the SMOT group. In addition, the failure rate of TT angle correction was significantly higher in the SMOT group (P = 0.016) than in the SMOT with MDA group. CONCLUSION: SMOT is a promising procedure for functional improvement and malalignment correction for varus ankle osteoarthritis, even in patients with increased talar tilt. If SMOT is combined with MDA, there can be an improvement in the correction of the increased talar tilt. LEVEL OF EVIDENCE: Level III, a retrospective comparative study.

Structural characterisation and discrimination of the aerial parts of Paris polyphylla var. yunnanensis and Paris polyphylla var. chinensis by UHPLC-QTOF-MS coupled with multivariate data analysis.

INTRODUCTION: As sources of Rhizoma Paridis are facing shortages, utilising the aerial parts of Paris polyphylla has emerged as a promising additional source. However, the components in the aerial parts still need to be explored, and it is difficult to distinguish the aerial parts of P. polyphylla Smith var. yunnanensis (PPY) and P. polyphylla var. chinensis (PPC), two varieties of P. polyphylla. OBJECTIVE: This study aimed to establish a comprehensive platform to characterise steroid saponins from the aerial parts of PPY and PPC and to discriminate these two varieties. METHODOLOGY: A dereplication approach and ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) analysis were used for the characterisation of steroidal saponins in the aerial parts of PPY and PPC. Multivariate statistical analysis was performed to differentiate these two varieties and screen discriminant variables. In addition, a genetic algorithm-optimised for support vector machines (GA-SVM) model was developed to predict P. polyphylla samples. The distribution of steroidal saponins in PPY and PPC was visualised by a heatmap. RESULTS: A total of 102 compounds were characterised from the aerial parts of PPY and PPC by dereplication. A clear separation of PPY and PPC was achieved, and 35 saponins were screened as marker compounds. The established GA-SVM model showed excellent prediction performance with a prediction accuracy of 100%. CONCLUSIONS: Many steroid saponins that have been reported in Rhizoma Paridis also exist in the aerial parts of P. polyphylla. Samples from the aerial parts of PPY and PPC could be discriminated using our platform.

EH-42: A Novel Small Molecule Induces Apoptosis and Inhibits Migration and Invasion of Human Hepatoma Cells through Suppressing STAT3 Signaling Pathway.

BACKGROUND: Since signal transducer and activator of transcription 3 (STAT3) is aberrantly activated in hepatocellular carcinoma (HCC) and plays a key role in this tumor progression. Inhibition of the STAT3 signaling pathway has been considered as an effective therapeutic strategy for suppressing HCC development. OBJECTIVE: In this study, we investigated the anti-cancer effects of EH-42 on HCC cells and tried to explain the underlying mechanism. METHODS: MTT assay, colon formation assay and AnnexinV-FITC/PI double-staining assay were performed to assess the effects of EH-42 on cell growth and survival. Wound healing assay and transwell invasion assay were performed to assess the effects of EH-42 on cell migration and invasion. Western blotting assay was performed to analyze the effects of EH-42 on relative proteins. RESULTS: According to the MTT assay, colon formation assay and AnnexinV-FITC/PI doublestaining assay, EH-42 could suppress the growth and induce apoptosis of HCC cells in a dosedependent manner. Further western blotting assay showed that the inhibitory effects of EH-42 on cell growth and survival were caused by activating caspase 3/9, suppressing the phospho-STAT3 (Tyr 705) and downregulating anti-apoptotic proteins like Bcl-2/Bcl-xL. Moreover, migration and invasion abilities of HCC cells were also inhibited by EH-42 in the wound healing assay and transwell invasion assay. The potential mechanism was that EH-42 could inhibit HCC metastasis via reversing epithelial-mesenchymal transition and downregulating the secretion of MMPs. CONCLUSION: Taken together, these findings suggested that EH-42 could be a potential therapeutic agent for HCC treatment.

ent-Sauchinone as Potential Anticancer Agent Inhibiting Migration and Invasion of Human Liver Cancer Cells via Suppressing the STAT3 Signaling Pathway.

ent-Sauchinone, a lignan isolated from Saururus chinensis (Lour.) Baill., was reported that it could modulate the expression of signal transducer and activator of transcription 3 (STAT3). Since STAT3 plays a key role in invasion, migration, and metastasis of cancer, we investigated whether ent-sauchinone could exert promising inhibitory effects on the invasion and migration of the metastatic human liver cancer cell line SMMC-7721 in the present study. ent-Sauchinone was extracted from dried herbs of Saururus chinensis (Lour.) Baill. Human liver cancer cell lines SMMC-7721 and HCCLM3 were used to test the effect of ent-sauchinone on cell viability. The IC50 values and time-dependent effect of ent-sauchinone were determined by MTT assay. Cell migration and invasion of SMMC-7721 were evaluated by the wound healing test and transwell assay respectively, the known anti-metastasis agent curcumin was used as a positive control. Western blotting assay was used to investigate relevant molecular mechanisms of cell invasion and migration. Though ent-sauchinone didn't show high cytotoxicity, the wound healing assay and transwell migration assay revealed a profound impairment in the metastatic potential of SMMC-7721 cells due to down-regulation of N-cadherin, MMP-2, and MMP-9 proteins induced by inhibiting the phosphorylation of STAT3. These findings suggest that ent-sauchinone could be used as a promising agent to treat cancer metastasis.

Development of a reactive force field for the Fe-C interaction to investigate the carburization of iron.

The approach of molecular dynamics with Reactive Force Field (ReaxFF) is a promising way to investigate the carburization of iron which is pivotal in the preparation of desired iron-based materials and catalysts. However, it is a challenge to develop a reliable ReaxFF to describe the Fe-C interaction, especially when it involves bond rearrangement. In this work, we develop an exclusive set of Reactive Force Field (ReaxFF) parameters, denoted RPOIC-2017, to describe the diffusion behavior of carbon atoms in the α-Fe system. It inherited some partial parameters in 2012 (ReaxFF-2012) which are suitable for hydrogen adsorption and dissociation. This set of parameters is trained against data from first-principles calculations, including the equations of state of α-Fe, the crystal constant of Fe3C and Fe4C, a variety of periodic surface structures with varying carbon coverages, as well as the barriers of carbon diffusion in the α-Fe bulk and on diverse surfaces. The success in predicting the carbon diffusion coefficient and the diffusion barrier using the developed RPOIC-2017 potential demonstrates that the performance is superior to that of the traditional MEAM potential. The new ReaxFF for the Fe-C interaction developed in this work is not only essential for the design of novel iron based materials, but could also help understand atomic arrangements and the interfacial structure of iron carbides.

Application of the dimensional reduction formalism to Pb9-xBax[Li2(P2O7)2(P4O13)2] (x = 0, 2, 6, 7): a series of phosphates with two types of isolated polyphosphate groups.

A series of phosphates, Pb9-xBax[Li2(P2O7)2(P4O13)2] (x = 0, 2, 6, 7), have been synthesized by a high temperature solution method and the crystal structures were determined by single crystal X-ray diffraction. They are isostructural and crystallize in the triclinic space group P1[combining macron]. It is interesting that there are two kinds of isolated polyphosphate anionic groups coexisting in the crystal structure, which is rare among phosphates. Their structures exhibit zero-dimensional [Li2(P2O7)2(P4O13)2]18- anionic clusters constructed by the LiO4, P2O7 and P4O13 groups, which are separated by the Pb2+ or Ba2+ cations. The structure of Pb9[Li2(P2O7)2(P4O13)2] could be obtained using Li2O as a dimensional reduction agent to dismantle Pb3P4O13. In addition, the infrared spectra and the UV-Vis-NIR diffuse reflectance spectra, as well as thermal analyses are reported. The first-principles theoretical studies are also carried out to understand the relationship between their electronic structures and linear optical properties.

Triterpenoids-Enriched Extract from the Aerial Parts of Salvia miltiorrhiza Regulates Macrophage Polarization and Ameliorates Insulin Resistance in High-Fat Fed Mice.

Adipose tissue inflammation and macrophage polarization are tightly associated with the development of obesity-associated insulin resistance. Our previous studies have demonstrated the triterpenoids-enriched extract from the aerial parts of Salvia miltiorrhiza (TTE) could significantly improve atherosclerosis in LDLR-/- mice. However, its molecular mechanisms of TTE ameliorating insulin resistance remain unclear. In the present study, obesity model with insulin resistance induced by feeding high-fat diet (HFD) was established. Dietary TTE attenuated hyperlipidemia, improved glucose intolerance in mice and mediated the activation of IRS-1/PI3K/Akt insulin signaling pathway. Meanwhile, dietary TTE also attenuated macrophage infiltrations into adipose tissue and modified the phenotype ratio of M1/M2 macrophages. Furthermore, our results showed that TTE regulated the polarization of macrophages partly via adenosine monophosphate-activated kinase (AMPK). Taken together, these findings suggested that TTE has a potential clinical utility in improving insulin resistance. Its mechanisms might be contributed to its beneficial effects on macrophage polarization via AMPK. Copyright © 2016 John Wiley & Sons, Ltd.

How far away are iron carbide clusters from the bulk?

Combining the basin hopping structure searching algorithm and density functional theory, the iron carbide clusters, FexCy (x ≤ 8 and y ≤ 8), and clusters with various stoichiometries (Fe2nCn, Fe3nCn, FenC2n, FenC3n and FenC4n (n = 1-7), Fe5nC2n, and Fe4nCn (n = 1-5)) are predicted. The stable structures of iron rich carbide clusters are composed of C-C dimers or single C atoms on the surface of the clusters, which are remarkably different from their corresponding bulk structures, where the carbon atoms are atomically distributed in the iron matrix. The most stable carbon rich clusters are highly diverse in topology (bowl, basket, plane, shoe, necklace, etc.) with long carbon chains. The Bader charge analysis shows that the size effect on iron carbide clusters is an electronic tuning. Large carbon-rich clusters appear even under low carbon chemical potentials, whereas small iron-rich clusters are only energetically stable in high carbon chemical potentials, which indicates that changing the carbon chemical potential can tune the morphology (size and stoichiometry) of the iron carbide clusters. These results may help us understand the catalytic activity of iron and iron carbides in reactions such as the Fischer-Tropsch synthesis and the carbon nanotube formation process.

Pharmacokinetic profiles of falcarindiol and oplopandiol in rats after oral administration of polyynes extract of Oplopanax elatus.

Polyynes, such as facarindiol (FAD) and oplopandiol (OPD), are responsible for anticancer activities of Oplopanax elatus (O. elatus). A novel approach to pharmacokinetics determination of the two natural polyynes in rats was developed and validated using a liquid chromatography-electrospray ionization-mass spectrometry (LC-MS) method. Biosamples were prepared by liquid-liquid extraction using ethyl acetate/n-hexane (V : V = 9 : 1) and the analytes were eluted on an Agilent ZORBAX Eclipse Plus C18 threaded column (4.6 mm × 50 mm, 1.8 µm) with the mobile phase of acetonitrile-0.1% aqueous formic acid at a flow-rate of 0.5 mL·min(-1) within a total run time of 11 min. All analytes were simultaneously monitored in a single-quadrupole mass spectrometer in the selected ion monitoring (SIM) mode using electrospray source in positive mode. The method was demonstrated to be rapid, sensitive, and reliable, and it was successfully applied to the pharmacokinetic studies of the two polyynes in rat plasma after oral administration of polyynes extract of O. elatus.

When Density Functional Approximations Meet Iron Oxides.

Three density functional approximations (DFAs), PBE, PBE+U, and Heyd-Scuseria-Ernzerhof screened hybrid functional (HSE), were employed to investigate the geometric, electronic, magnetic, and thermodynamic properties of four iron oxides, namely, α-FeOOH, α-Fe2O3, Fe3O4, and FeO. Comparing our calculated results with available experimental data, we found that HSE (a = 0.15) (containing 15% "screened" Hartree-Fock exchange) can provide reliable values of lattice constants, Fe magnetic moments, band gaps, and formation energies of all four iron oxides, while standard HSE (a = 0.25) seriously overestimates the band gaps and formation energies. For PBE+U, a suitable U value can give quite good results for the electronic properties of each iron oxide, but it is challenging to accurately get other properties of the four iron oxides using the same U value. Subsequently, we calculated the Gibbs free energies of transformation reactions among iron oxides using the HSE (a = 0.15) functional and plotted the equilibrium phase diagrams of the iron oxide system under various conditions, which provide reliable theoretical insight into the phase transformations of iron oxides.

American Ginseng Attenuates Colitis-Associated Colon Carcinogenesis in Mice: Impact on Gut Microbiota and Metabolomics.

Inflammatory bowel disease is a risk factor for colorectal cancer initiation and development. In this study, the effects of American ginseng on chemically induced colitis and colon carcinogenesis were evaluated using an azoxymethane (AOM)/dextran sulfate sodium (DSS) mouse model. During the acute phase on day 15, the oral administration of ginseng (15 and 30 mg/kg/day) significantly suppressed AOM/DSS-induced colitis, as demonstrated by the disease activity index and colon tissue histology. During the chronic phase in week 13, AOM/DSS-induced tumor multiplicity was significantly suppressed by ginseng. Ginseng significantly attenuated the increase of inflammatory cytokines, such as IL1α, IL1ß, IL6, G-CSF, and GM-CSF. Serum metabolomics data in the PCA plots showed good separation between the AOM/DSS model and ginseng-treated mice, and the most important endogenous metabolite changes were identified. The 16S rRNA data showed that after AOM/DSS, the microbiome community in the model group was obviously changed, and ginseng inhibited these changes. Fecal metabolomics analysis supported these findings. In conclusion, oral ginseng significantly decreased AOM/DSS-induced colitis and colon carcinogenesis by inhibiting inflammatory cytokines and restoring the metabolomics and microbiota profiles accordingly. Selective endogenous small molecules could be used as biomarkers to elucidate the effects of ginseng treatment. Cancer Prev Res; 9(10); 803-11. ©2016 AACR.

Mössbauer Spectroscopy of Iron Carbides: From Prediction to Experimental Confirmation.

The Mössbauer spectroscopy of iron carbides (α-Fe, γ'-FeC, η-Fe2C, ζ-Fe2C, χ-Fe5C2, h-Fe7C3, θ-Fe3C, o-Fe7C3, γ'-Fe4C, γ''-Fe4C, and α'-Fe16C2) is predicted utilizing the all electron full-potential linearized augmented plane wave (FLAPW) approach across various functionals from LDA to GGA (PBE, PBEsol, and GGA + U) to meta-GGA to hybrid functionals. To validate the predicted MES from different functionals, the single-phase χ-Fe5C2 and θ-Fe3C are synthesized in experiment and their experimental MES under different temperature (from 13 K to 298 K) are determined. The result indicates that the GGA functional (especially, the PBEsol) shows remarkable success on the prediction of Mössbauer spectroscopy of α-Fe, χ-Fe5C2 and θ-Fe3C with delocalized d electrons. From the reliable simulations, we propose a linear relationship between Bhf and µB with a slope of 12.81 T/µB for iron carbide systems and that the proportionality constant may vary from structure to structure.

Corosolic acid inhibits adipose tissue inflammation and ameliorates insulin resistance via AMPK activation in high-fat fed mice.

BACKGROUND: Adipose tissue inflammation is tightly associated with the development of insulin resistance. Corosolic acid (CRA), a natural triterpenoid, is well known as "phyto-insulin" due to its insulin-like activities. However, its underlying mechanism remains unknown. PURPOSE: In this study, we investigated the mechanisms of CRA on improving insulin resistance both in vivo and in vitro. METHODS: C57BL/6 mice were fed with normal diet, high-fat diet (HFD) or HFD with CRA, respectively. General biochemical parameters in blood and glucose intolerance in mice were assayed. Meanwhile, proinflammatory cytokines and macrophage infiltrations in adipose tissues were analyzed by real-time PCR and immunohistochemical staining. The effects of CRA on insulin signaling transduction and AMPK activity in adipose tissues were investigated by western blot. Furthermore, the effects of CRA on AMPK were confirmed on 3T3-L1 cells by using both AMPK inhibitor and AMPKα1/2-specific siRNA RESULTS: CRA attenuated hyperlipidemia, improved insulin sensitivity and glucose intolerance in mice. Meanwhile, it alleviated inflammation in adipose tissues, demonstrated by the suppression of IKKß phosphorylation and down-regulation of gene expressions of proinflammatory cytokines. Histological analysis revealed that CRA attenuated macrophage infiltrations into adipose tissue. It also improved insulin signaling transduction by modification of Ser/Thr phosphorylation of IRS-1 and downstream Akt, thereby improved insulin sensitivity in HFD-fed mice. Furthermore, CRA regulated AMPK activation in a LKB1-dependent manner. AMPKα knockdown in adipocytes abolished the inhibitory effects of CRA on IKKß and IRS-1 serine phosphorylation, indicating that CRA inhibited inflammation and ameliorated insulin resistance via AMPK activation. CONCLUSIONS: CRA inhibited inflammation with improvement in adipose tissue dysfunction and ameliorated insulin resistance in an AMPK-dependent manner.