Intercalation of magnetic iron atoms through graphene formed on the SiC(0001) surface is found to induce significant changes in the electronic properties of graphene due mainly to the Fe-induced ...asymmetries in charge as well as spin distribution. From our synchrotron-based photoelectron spectroscopy data together with ab initio calculations, we observe that the Fe-induced charge asymmetry results in the formation of a quasi-free-standing bilayer graphene while the spin asymmetry drives multiple spin-split bands. We find that Fe adatoms are best intercalated upon annealing at 600 °C, exhibiting split linear π-bands, characteristic of a bilayer graphene, but much diffused. Subsequent changes in the C 1s, Si 2p, and Fe 3p core levels are consistently described in terms of Fe-intercalation. Our calculations together with a spin-dependent tight binding model ascribe the diffuse nature of the π-bands to the multiple spin-split bands originated from the spin-injected carbon atoms residing only in the lower graphene layer.
Metastasis is the predominant cause of death in breast cancer patients. Several lines of evidence have shown that microRNAs (miRs) can have an important role in cancer metastasis. Using isogenic ...pairs of low and high metastatic lines derived from a human breast cancer line, we have identified miR-149 to be a suppressor of breast cancer cell invasion and metastasis. We also identified GIT1 (G-protein-coupled receptor kinase-interacting protein 1) as a direct target of miR-149. Knockdown of GIT1 reduced migration/invasion and metastasis of highly invasive cells. Re-expression of GIT1 significantly rescued miR-149-mediated inhibition of cell migration/invasion and metastasis. Expression of miR-149 impaired fibronectin-induced focal adhesion formation and reduced phosphorylation of focal adhesion kinase and paxillin, which could be restored by re-expression of GIT1. Inhibition of GIT1 led to enhanced protein degradation of paxillin and α5β1 integrin via proteasome and lysosome pathways, respectively. Moreover, we found that GIT1 depletion in metastatic breast cancer cells greatly reduced α5β1-integrin-mediated cell adhesion to fibronectin and collagen. Low level of miR-149 and high level of GIT1 was significantly associated with advanced stages of breast cancer, as well as with lymph node metastasis. We conclude that miR-149 suppresses breast cancer cell migration/invasion and metastasis by targeting GIT1, suggesting potential applications of the miR-149-GIT1 pathway in clinical diagnosis and therapeutics.
Although the medial prefrontal cortex (mPFC) is known to play a crucial role in rodent social behavior, little is known about mPFC neural correlates of social behavior. In the present study, we ...examined single-neuron activity in the mPFC of mice performing a modified version of the three-chamber test. We found that a subset of mPFC neurons elevate discharge rates when approaching a stranger mouse but not when approaching an inanimate object or an empty chamber. Our results reveal mPFC neural activity that is correlated with social approach behavior in a widely used social-interaction paradigm. These findings might be helpful for future investigations of mPFC neural processes underlying social interaction in health and disease.
Although the prefrontal cortex is known to play a crucial role in rodent social behavior, little is known about prefrontal neural correlates of social behavior. This study shows that the activity of a subset of prefrontal neurons increases in association with social approach behavior during a three-chamber test-a widely used behavioral paradigm. Such responses might be a signature of prefrontal neural processes underlying social approach behavior.
Production of the industrial chemical propylene oxide is energy-intensive and environmentally unfriendly. Catalysts based on bulk silver surfaces with direct propylene epoxidation by molecular oxygen ...have not resolved these problems because of substantial formation of carbon dioxide. We found that unpromoted, size-selected Ag₃ clusters and approximately 3.5-nanometer Ag nanoparticles on alumina supports can catalyze this reaction with only a negligible amount of carbon dioxide formation and with high activity at low temperatures. Density functional calculations show that, relative to extended silver surfaces, oxidized silver trimers are more active and selective for epoxidation because of the open-shell nature of their electronic structure. The results suggest that new architectures based on ultrasmall silver particles may provide highly efficient catalysts for propylene epoxidation.
L-ascorbate (L-ascorbic acid, vitamin C) clearly has an inhibitory effect on cancer cells. However, the mechanism underlying differential sensitivity of cancer cells from same tissue to L-ascorbate ...is yet to be clarified. Here, we demonstrate that L-ascorbate has a selective killing effect, which is influenced by sodium-dependent vitamin C transporter 2 (SVCT-2) in human breast cancer cells. Treatment of human breast cancer cells with L-ascorbate differentially induced cell death, dependent on the SVCT-2 protein level. Moreover, knockdown of endogenous SVCT-2 via RNA interference in breast cancer cells expressing high levels of the protein induced resistance to L-ascorbate treatment, whereas transfection with SVCT-2 expression plasmids led to enhanced L-ascorbate chemosensitivity. Surprisingly, tumor regression by L-ascorbate administration in mice bearing tumor cell xenograft also corresponded to the SVCT-2 protein level. Interestingly, SVCT-2 expression was absent or weak in normal tissues, but strongly detected in tumor samples obtained from breast cancer patients. In addition, enhanced chemosensitivity to L-ascorbate occurred as a result of caspase-independent autophagy, which was mediated by beclin-1 and LC3 II. In addition, treatment with N-acetyl-L-cysteine, a reactive oxygen species (ROS) scavenger, suppressed the induction of beclin-1 and LC3 II, implying that the differential SVCT-2 protein-dependent L-ascorbate uptake was attributable to intracellular ROS induced by L-ascorbate, subsequently leading to autophagy. These results suggest that functional SVCT-2 sensitizes breast cancer cells to autophagic damage by increasing the L-ascorbate concentration and intracellular ROS production and furthermore, SVCT-2 in breast cancer may act as an indicator for commencing L-ascorbate treatment.
Recent developments in the instrumentation and data analysis of synchrotron small‐angle X‐ray scattering (SAXS) on biomolecules in solution have made biological SAXS (BioSAXS) a mature and popular ...tool in structural biology. This article reports on an advanced endstation developed at beamline 13A of the 3.0 GeV Taiwan Photon Source for biological small‐ and wide‐angle X‐ray scattering (SAXS–WAXS or SWAXS). The endstation features an in‐vacuum SWAXS detection system comprising two mobile area detectors (Eiger X 9M/1M) and an online size‐exclusion chromatography system incorporating several optical probes including a UV–Vis absorption spectrometer and refractometer. The instrumentation and automation allow simultaneous SAXS–WAXS data collection and data reduction for high‐throughput biomolecular conformation and composition determinations. The performance of the endstation is illustrated with the SWAXS data collected for several model proteins in solution, covering a scattering vector magnitude q across three orders of magnitude. The crystal‐model fittings to the data in the q range ∼0.005–2.0 Å−1 indicate high similarity of the solution structures of the proteins to their crystalline forms, except for some subtle hydration‐dependent local details. These results open up new horizons of SWAXS in studying correlated local and global structures of biomolecules in solution.
A new endstation for biological small‐ and wide‐angle X‐ray scattering is detailed, which provides development opportunities for studying correlated local and global structures of biomolecules in solution.
The large volume of adult living donor liver transplantations (ALDLTs) at our center affords a unique opportunity to examine the impact of acute‐on‐chronic liver failure (ACLF) among high–Model for ...End‐Stage Liver Disease MELD score patients. From February 1998 to March 2010, 1958 cirrhotic recipients were analyzed to study the relationship between MELD scores and ALDLT outcomes. A total of 327 high‐MELD score recipients were categorized into ACLF and non‐ACLF groups, and their outcomes were compared. The 5‐year graft and patient survival in the high‐MELD group were 75.2% and 76.4%, respectively, which were significantly worse than the low and intermediate MELD groups. The presence of ACLF associated with higher MELD scores appeared to be the dominant factor responsible for the inferior results of patients with MELD score of 30–34 points. The 5‐year graft survivals in the ACLF group was 70.5% and in the non‐ACLF group it was 81.0% (p = 0.035). Therefore, ALDLT should be performed as soon as possible in high‐MELD score patients prior to ACLF development. Moreover, ACLF patients should be separately categorized when analyzing the outcomes of ALDLT. ALDLT for ACLF patients should not be discouraged because favorable outcomes can be expected through timely ALDLT and comprehensive management.
While adult living donor liver transplantation should be performed as soon as possible before acute‐on‐chronic liver failure develops, it should not be discouraged for patients with acute‐on‐chronic liver failure since timely transplantation and comprehensive management can bring a favorable outcome.
This article explores the potential learning benefits of three-dimensional (3-D) virtual learning environments (VLEs). Drawing on published research spanning two decades, it identifies a set of ...unique characteristics of 3-D VLEs, which includes aspects of their representational fidelity and aspects of the learner-computer interactivity they facilitate. A review of applications of 3-D VLEs is presented, leading to the identification of a series of learning affordances of such environments. These affordances include the facilitation of tasks that lead to enhanced spatial knowledge representation, greater opportunities for experiential learning, increased motivation/engagement, improved contextualisation of learning and richer/more effective collaborative learning as compared to tasks made possible by 2-D alternatives. The authors contend that the continued development of and investment in 3-D games, simulations and virtual worlds for educational purposes should be considered contingent on further investigation into the precise relationships between the unique characteristics of 3-D VLEs and their potential learning benefits. To this end, they conclude by proposing an agenda or 'roadmap' for future research that encompasses empirical studies aimed at exploring these relationships, as well as those aimed at deriving principles and guidelines to inform the design, development and use of 3-D virtual environments for learning. Author abstract
Background and purpose
We investigated changes in deep gray matter (DGM) volume and its relationship to cognition and clinical factors in a large cohort of patients with neuromyelitis optica spectrum ...disorder (NMOSD) and compared them with results from multiple sclerosis (MS).
Methods
Brain magnetic resonance imaging (3 Tesla) and clinical data from 91 patients with NMOSD, 52 patients with MS and 44 healthy controls (HCs) were prospectively evaluated. Differences in DGM volumes were compared among groups. The relationships between DGM atrophy and clinical variables were also analysed.
Results
Patients with NMOSD exhibited significantly reduced thalamic volumes compared with HCs (P = 0.029), although this atrophy was less severe than that seen in patients with MS (P < 0.001). DGM atrophy was restricted to the thalamus in NMOSD, but it was broadly distributed in MS. Patients with NMOSD with cognitive impairment (CI) exhibited more severe thalamic atrophy than those with cognitive preservation (P = 0.017) and HCs (P = 0.003), whereas patients with MS with CI revealed DGM atrophy across the entire structure, with the exception of the bilateral pallidum, left hippocampus and amygdala, relative to HCs. The Expanded Disability Status Scale score was correlated with thalamic atrophy in both NMOSD and MS. Patients with NMOSD with brain lesions demonstrated more severe thalamic atrophy than did those without brain lesions and HCs (P < 0.001).
Conclusions
The DGM atrophy was less severe and more selectively distributed in NMOSD than in MS. Thalamic atrophy was associated with clinical disability, including CI, in both NMOSD and MS.
Summary
The use of calcium phosphate bone cement has been described to allow for retention of reduction. Therefore, we evaluated whether augmentation with resorbable calcium phosphate could improve ...fracture stability in osteoporotic hip fractures. The results showed that augmentation with calcium phosphate cement significantly improved the stability of intertrochanteric fractures.
Introduction
The aim with this study was to measure whether augmentation with resorbable calcium phosphate cement could improve fracture stability in osteoporotic hip fractures.
Methods
We retrospectively reviewed 82 patients who underwent closed reduction and internal fixation with proximal femoral nail (PFN) for unstable intertrochanteric fractures between 2014 and 2017. In 42 of 82 patients, patients were treated with a PFN alone (group I). These patients were compared with 40 patients for whom the same device combined with calcium phosphate cement for augmentation was used (group II). Questionnaire surveys or telephone interviews were conducted and patients completed a self-report Harris hip score (HHS) and visual analog scale (VAS) scores. Radiographic outcomes including mean sliding distance of screw, femoral shortening, and varus collapse were compared. Postoperative complications were compared.
Results
Clinical outcomes at 6 months after surgery were equivalent in both groups. Screw sliding, femoral shortening, and varus collapse were all significantly reduced in the cemented group at the last follow-up (
p
< 0.001,
p
= 0.005,
p
< 0.001, respectively). A total of 9 (21%) complications occurred in group I. In contrast, 2 (5%) complications were seen in group II (
p
= 0.029).
Conclusions
Augmentation with calcium phosphate cement significantly improved the stability of intertrochanteric fractures fixed with a PFN and reduced overall failure rates. We believe augmentation with resorbable calcium phosphate cement for osteoporotic hip fractures is a reasonable option in selected patients.
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