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.
In this study, vibration characteristics of a piezoelectric nanobeam embedded in a viscoelastic medium are investigated based on nonlocal Euler–Bernoulli beam theory. In doing this, the governing ...equations of motion and boundary conditions for vibration analysis are first derived using Hamilton’s principle, where nonlocal effect, piezoelectric effect, flexoelectric effect, and viscoelastic medium are considered simultaneously. Subsequently, the transfer function method is employed to obtain the natural frequencies and corresponding mode shapes in closed form for the embedded piezoelectric nanobeam with arbitrary boundary conditions. The proposed mechanics model is validated by comparing the obtained results with those available in the literature, where good agreement is achieved. The effects of nonlocal parameter, boundary conditions, slenderness ratio, flexoelectric coefficient, and viscoelastic medium on vibration responses are also examined carefully for the embedded nanobeam. The results demonstrate the efficiency and robustness of the developed model for vibration analysis of a complicated multi-physics system comprising piezoelectric nanobeam with flexoelectric effect, viscoelastic medium, and electrical loadings.
Fear acquisition and generalization play key roles in promoting the survival of mammals and contribute to anxiety disorders. While previous research has provided much evidence for the repercussions ...of social exclusion on mental health, how social exclusion affects fear acquisition and generalization has received scant attention. In our study, participants were divided into two groups according to two Cyberball paradigm conditions (exclusion/inclusion). Both groups underwent a Pavlovian conditioning paradigm, functional near-infrared spectroscopy (fNIRS), and skin conductance response (SCR) assessments. We aimed to determine the effects of social exclusion on fear acquisition and generalization and whether modulation of the medial prefrontal cortex (mPFC) mediates this relationship. Our results showed that socially excluded participants featured significantly higher and lower shock risk scores to safety stimuli (conditioned stimulus, CS-) and threatening stimuli (CS+), respectively, than did socially included subjects during fear acquisition. The exclusion group had increased skin conductance responses (SCRs) to CS and exhibited heightened shock risk and increased SCRs to generalized stimuli compared with the inclusion group. The fNIRS results demonstrated that the CS + evoked larger oxy-Hb changes in the mPFC in the inclusion group than in the exclusion group during fear acquisition. Furthermore, the oxy-Hb of left mPFC of CS + mediated the effect on the association between social exclusion and perceived risk of CS+ in the fear acquisition. Our results indicate that social exclusion impairs fear acquisition and generalization via the mediation of the mPFC and that social exclusion increases susceptibility to anxiety disorders through bias processing of fear discrimination in fear acquisition and generalization. By studying the role of social relationship in fear acquisition and generalization, our research provides new insights into the pathological mechanisms of anxiety disorder.
•Social exclusion impairs fear acquisition and generalization via the mediation of mPFC activation.•Social exclusion increases anxiety disorder susceptibility through bias processing.•The mPFC activation of the CS+ partially mediated the association between social exclusion and perceived risk of the CS+.•Improving resilience might prevent the negative effect of social exclusion on fear acquisition.
To investigate the safety and efficacy of intravenous thrombolysis with recombinant tissue plasminogen activator (rt-PA) in patients with acute ischemic stroke (AIS) and cerebral microbleeds (CMBs) ...and analyze the risk factors for hemorrhagic transformation (HT).
The clinical data of 220 patients with CMB within the first 4.5 h after the onset of acute ischemic stroke treated in our hospital from September 2018 to December 2019 were retrospectively analyzed. Then, these patients were evenly assigned into two groups based on whether the intravenous thrombolysis with rt-PA was adopted or not. Next, the neurological deficit was scored using the National Institute of Health stroke scale (NIHSS) before and after treatment, the modified Rankin scale (mRs) score of patients was recorded at 90 d after treatment, and the incidence rate and death rate of intracranial hemorrhage (ICH) after treatment were recorded and evaluated. Additionally, the univariate and logistic regression analyses were employed for the risk factors for HT in patients after thrombolysis.
The NIHSS score declined to (7.08±3.75) points and (7.83±4.22) points at 24 h after treatment and (3.67±3.63) points and (4.92±3.87) points at 7 d after treatment, respectively, in Thrombolysis group and Control group, which were significantly lower than those before treatment (p<0.05). The NIHSS score displayed no statistically significant difference between the two groups at 24 h after treatment (p=0.165), whereas it was markedly lower in Thrombolysis group than that in Control group at 7 d after treatment (p=0.015). At 90 d after treatment, there were 98 (89.1%) and 79 (71.8%) cases of good prognosis in Thrombolysis group and Control group, respectively, and the difference was statistically significant between the two groups (p=0.002). Besides, the number of patients with SICH and aSICH was 3 and 2 (2.7% vs. 1.8%, p=0.651) and 9 and 4 (8.2% vs. 3.6%, p=0.152) in Thrombolysis group and Control group, respectively, and the number of deaths was 7 and 5 (6.4% vs. 4.5%, p=0.553) in the two groups, showing no statistically significant difference. The results of univariate and multivariate analyses revealed that the time from stroke onset to thrombolysis, baseline NIHSS score, and history of atrial fibrillation were independent risk factors affecting the HT of patients undergoing intravenous thrombolysis odds ratio (OR) =1.330, 95% confidence interval (95% CI) =1.079-1.851, p=0.019; OR=1.592, 95% CI=1.025-2.767, p=0.010; OR=2.428, 95% CI=1.814-3.643, p=0.016.
Compared with those undergoing no intravenous thrombolysis with rt-PA, patients with acute ischemic stroke and CMB who received intravenous thrombolysis with rt-PA exhibit significantly improved short-term neurological function recovery and long-term prognosis, but the incidence and mortality rates of ICH have no statistically significant differences. Moreover, the time from stroke onset to thrombolysis, baseline NIHSS score, and history of atrial fibrillation are independent risk factors affecting the HT of patients treated with intravenous thrombolysis.
Rising sudden death among anaesthesiologists in China Zhang, H.-F.; Li, F.-X.; Lei, H.-Y. ...
British journal of anaesthesia : BJA,
July 2017, 20170701, 2017-07-01, 2017-07-00, Letnik:
119, Številka:
1
Journal Article
Digital technology provides methods to record and preserve cultural heritage, support conservation and restoration efforts, and share our collective past with a worldwide audience. Between 2011 and ...2017, the 3D Survey Group from Politecnico di Milano operated an annual workshop in the medieval village of Ghesc in which photogrammetry and laser-scanner surveys were carried out. The point cloud data acquired in these activities has become “time slices” documenting different stages of the preservation interventions in Ghesc and the evolution of advanced survey techniques. The main objective of this research is to streamline the workflow of delivering immersive and interactive experiences for complex heritage by directly utilising the 3D survey point cloud data, whether derived from a photogrammetric survey, static laser scanner, or mobile mapping.A point cloud-based multiplatform application is designed and delivered with versatile functions. It runs on PC and VR devices to provide virtual access to the village and narrate its revitalisation story. Additionally, it operates on mobile devices with an AR feature that brings vibrancy to the on-site experience. This application integrates high-fidelity point cloud models, detailed information on vernacular architecture in the Ossola Valley, and information on the preservation project with gamified learning experiences. The unconventional approach of using points as rendering primitives in virtual applications offers a practical solution for visualising complex heritage, enabling an efficient transition from the data collection stage to the data sharing stage without the need for 3D reconstruction and intricate BIM modelling.
Mixing is an effective strategy to improve the inhibition performance of corrosion inhibitors based on their synergistic effect. In this work, the synergistic inhibition effect of S-benzyl-L-cysteine ...(SBLC) and thiourea (TU) on the corrosion of carbon steel in the CO2-saturated oilfield produced water is studied by electrochemical tests and surface analysis. It is found that SBLC and TU exhibit a significant synergistic corrosion inhibition effect. Meanwhile, the synergistic mechanism is in-depth elucidated by theoretical calculations. The intermolecular interaction between SBLC and TU molecules leads to the formation of a more compact and stronger adsorbed film on carbon steel surface.
Display omitted
•Amino acid (SBLC) and thiourea (TU) were tested as compounded corrosion inhibitors for carbon steel in CO2 environment.•Electrochemical tests indicate that SBLC and TU exhibit significantly synergetic inhibition effect.•The adsorption of SBLC and TU on carbon steel surface is significantly strengthened after mixing.•The co-adsorbed SBLC+TU mixture film can effectively prevent the diffusion of corrosive particles to carbon steel surface.•Theoretical calculations were performed to in-depth explore the synergetic mechanism of SBLC and TU.
•A two-dimensional model for the design of flow fields in VRFBs is reported.•Uniformity of vanadium ion distribution is evaluated by uniformity factors.•Pressure drop is accurately captured in ...interdigitated and serpentine flow fields.•Performance of several design of flow fields for a large cell is studied.
In this work, we report a two-dimensional mathematical model for the design of flow fields in vanadium redox flow batteries (VRFBs). The model is validated by calculating the pressure drop, distribution uniformity of vanadium ions in an interdigitated flow field and a serpentine flow field for a 9-cm2 cell. The model is then used to simulate interdigitated and a series of parallel serpentine design of flow fields in a 410-cm2 cell. It is demonstrated that with an increase in the number of parallel serpentine channels, the pumping power decreases while the distribution of vanadium ions becomes less uniform. Among the design of flow fields studied in this work, the interdigitated design performs the lowest pumping power and the most uniform distributions of vanadium ions.
KDM2B (also known as FBXL10) controls stem cell self-renewal, somatic cell reprogramming and senescence, and tumorigenesis. KDM2B contains multiple functional domains, including a JmjC domain that ...catalyzes H3K36 demethylation and a CxxC zinc-finger that recognizes CpG islands and recruits the polycomb repressive complex 1. Here, we report that KDM2B, via its F-box domain, functions as a subunit of the CUL1-RING ubiquitin ligase (CRL1/SCF(KDM2B)) complex. KDM2B targets c-Fos for polyubiquitylation and regulates c-Fos protein levels. Unlike the phosphorylation of other SCF (SKP1-CUL1-F-box)/CRL1 substrates that promotes substrates binding to F-box, epidermal growth factor (EGF)-induced c-Fos S374 phosphorylation dissociates c-Fos from KDM2B and stabilizes c-Fos protein. Non-phosphorylatable and phosphomimetic mutations at S374 result in c-Fos protein which cannot be induced by EGF or accumulates constitutively and lead to decreased or increased cell proliferation, respectively. Multiple tumor-derived KDM2B mutations impaired the function of KDM2B to target c-Fos degradation and to suppress cell proliferation. These results reveal a novel function of KDM2B in the negative regulation of cell proliferation by assembling an E3 ligase to targeting c-Fos protein degradation that is antagonized by mitogenic stimulations.
PDF
