27 research outputs found
Coherent Dynamics of Charge Carriers in {\gamma}-InSe Revealed by Ultrafast Spectroscopy
For highly efficient ultrathin solar cells, layered indium selenide (InSe), a
van der Waals solid, has shown a great promise. In this paper, we study the
coherent dynamics of charge carriers generation in {\gamma}-InSe single
crystals. We employ ultrafast transient absorption spectroscopy to examine the
dynamics of hot electrons after resonant photoexcitation. To study the effect
of excess kinetic energy of electrons after creating A exciton (VB1 to CB
transition), we excite the sample with broadband pulses centered at 600, 650,
700 and 750 nm, respectively. We analyze the relaxation and recombination
dynamics in {\gamma}-InSe by global fitting approach. Five decay associated
spectra with their associated lifetimes are obtained, which have been assigned
to intraband vibrational relaxation and interband recombination processes. We
extract characteristic carrier thermalization times from 1 to 10 ps. To examine
the coherent vibrations accompanying intraband relaxation dynamics, we analyze
the kinetics by fitting to exponential functions and the obtained residuals are
further processed for vibrational analysis. A few key phonon coherences are
resolved and ab-initio quantum calculations reveal the nature of the associated
phonons. The wavelet analysis is employed to study the time evolution of the
observed coherences, which show that the low-frequency coherences last for more
than 5 ps. Associated calculations reveal that the contribution of the
intralayer phonon modes is the key determining factor for the scattering
between free electrons and lattice. Our results provide fundamental insights
into the photophysics in InSe and help to unravel their potential for
high-performance optoelectronic devices
The crosstalk between anoikis and epithelial-mesenchymal transition and their synergistic roles in predicting prognosis in colon adenocarcinoma
Anoikis and epithelial-mesenchymal transition (EMT) are significant phenomena occurring in distant metastasis of colon adenocarcinoma (COAD). A comprehensive understanding of their crosstalk and the identification of key genes are vital for treating the distant metastasis of COAD. The objective of this study was to design and validate accurate prognostic predictors for COAD patients based on the anoikis and EMT processes. We obtained gene signatures from various databases and performed univariate and multivariate Cox regression analyses, principal component analysis (PCA). The COAD patients were categorized into the worst prognosis group, the Anoikis Potential Index (API) Low + EMT Potential Index (EPI) High group and the others group. Then we utilized gene set enrichment analysis (GSEA) to identify differentially expressed genes and to establish a prognostic risk model. The model classified patients into high- or low-risk groups, with patients in the high-risk group displaying worse survival status. A nomogram was established to predict overall survival rates, demonstrating high specificity and sensitivity. Additionally, we connected the risk model to the tumor microenvironment (TME) using single-sample GSEA and the MCP counter tool, as well as evaluated the sensitivity to common chemotherapeutic drugs, such as Gefitinib and Gemcitabine. Lastly, cell and tissue experiments suggested a positive correlation among anoikis resistance, EMT, and liver/lung metastasis of COAD. This is the first study to comprehensively analyze the crosstalk between anoikis and EMT and offers new therapeutic targets for COAD metastasis patients
Multiple Visual Rating Scales Based on Structural MRI and a Novel Prediction Model Combining Visual Rating Scales and Age Stratification in the Diagnosis of Alzheimer's Disease in the Chinese Population
Objective: To explore the value of multiple visual rating scales based on structural MRI in the diagnosis of Alzheimer's disease (AD) in the Chinese population.Materials and Methods: One hundred patients with AD and 100 age- and gender- matched cognitively normal controls were enrolled in this study. All the participants underwent neuropsychological tests and a structural MRI scan of the brain, among them, 42 AD cases and 47 cognitively normal controls also underwent 3D-T1 weighted sequence used for the analysis of voxel-based morphometry (VBM). The AD cases were divided into mild and moderate–severe groups according to the mini-mental state examination. Each participant was evaluated by two trained radiologists who were blind to the clinical information, according to the six visual rating scales, including for medial temporal lobe atrophy (MTA), posterior atrophy (PA), anterior temporal (AT), orbitofrontal (OF) cortex, anterior cingulate (AC), and fronto-insula (FI). Finally, we estimated the relationship between the visual rating scales and the volume of corresponding brain regions, using correlation analysis, and evaluated the specificity and sensitivity of every single scale and combination of multiple scales in the diagnosis of AD, using a receiver operating characteristic (ROC) curve and establishing a logistic regression model.Results: The optimal cutoff of all six visual rating scales for distinguishing AD cases from normal controls was 1.5. Using automated classification based on all six rating scales, the accuracy for distinguishing AD cases from healthy controls ranged from 0.68 to 0.80 (for mild AD) and 0.77–0.90 (for moderate–severe AD), respectively. A diagnostic prediction model with a combination of MTA and OF results was made as follows: Score = BMTA(score) + BOF(score) −1.58 (age < 65 years); Score = BMTA(score) + BOF(score) −4.09 (age ≥65 years). The model was superior to any single visual rating scale in the diagnosis of mild AD (P < 0.05).Conclusion: Each of the six visual rating scales could be applied to the diagnosis of moderate-severe AD alone in the Chinese population. A prediction model of the combined usage of MTA, OF, and age stratification for the early diagnosis of AD was preliminarily established
Experimental and Numerical Investigation of Polymer-Based 3D-Printed Lattice Structures with Largely Tunable Mechanical Properties Based on Triply Periodic Minimal Surface
Triply periodic minimal surfaces (TPMSs) have demonstrated significant potential in lattice structure design and have been successfully applied across multiple industrial fields. In this work, a novel lattice structure with tunable anisotropic properties is proposed based on two typical TPMS types, and their mechanical performances are studied both experimentally and numerically after being fabricated using a polymer 3D printing process. Initially, adjustments are made to the original TPMS lattice structures to obtain honeycomb lattice structures, which are found to possess significant anisotropy, by utilizing numerical homogenization methods. Based on this, a continuous self-twisting deformation is proposed to change the topology of the honeycomb lattice structures to largely tune the mechanical properties. Quasi-static compression experiments are conducted with different twisting angles, and the results indicate that self-twisting can affect the mechanical properties in specific directions of the structure, and also enhance the energy absorption capacity. Additionally, it mitigates the risk of structural collapse and failure during compression while diminishing structural anisotropy. The proposed self-twisting strategy, based on honeycomb lattice structures, has been proven valuable in advancing the investigation of lattice structures with largely tunable mechanical properties
BILABIAL TRILL INDUCED BY FRICATIVE HIGH ROUNDED VOWEL: THE EMERGING OF "TB" IN THE WU DIALECT OF SU-WAN BOUNDARY
10.1353/jcl.2019.0006JOURNAL OF CHINESE LINGUISTICS471172-19
Novel high ionic conductivity electrolyte membrane based on semiconductor La \u3c inf\u3e 0.65 Sr \u3c inf\u3e 0.3 Ce \u3c inf\u3e 0.05 Cr \u3c inf\u3e 0.5 Fe \u3c inf\u3e 0.5 O \u3c inf\u3e 3-Δ for low-temperature solid oxide fuel cells
© 2019 The p-type semiconductor La0.65Sr0.3Ce0.05Cr0.5Fe0.5O3-δ (CLSCrF) is for the first time composited with the ionic conductor Ce0.8Sm0.2O2-δ (SDC) to prepare high ionic conductivity electrolyte membranes for low-temperature solid oxide fuel cells (LT-SOFCs). Experimental results illuminate that the introduction of moderate semiconductor into ionic membrane can improve membrane\u27s ionic conductivity, reduce cell\u27s polarization resistance and accelerate the electrode reaction in cathode zone. With 30 wt% CLSCrF incorporated into the SDC membrane, the cell delivers a maximum power density of 837 mW cm−2 at 550 °C with the membrane ionic conductivity as high as 0.15 S cm−1. This conductivity value is nearly 2 times higher than that of the simplex ionic membrane SDC. The rectification characteristic test indicates that there is a physical junction effect in the CLSCrF-SDC cells, which can prevent electrons from passing through internally and avoid the short circuit problem effectively. Moreover, the short-term durability test reveals that the developed CLSCrF-SDC cell is capable of stably operating for 18 h at 550 °C under a fixed current density of 234 mA cm−2. This study suggests that the CLSCrF-SDC is a promising membrane to advance the LT-SOFCs development