The thickness-dependent electronic states and physical properties of two-dimensional materials suggest great potential applications in electronic and optoelectronic devices. However, the enhanced surface effect in ultra-thin materials might significantly influence the structural stability, as well as the device reliability. Here, we report a spontaneous phase transformation of gallium telluride (GaTe) that occurred when the bulk was exfoliated to a few layers. Transmission electron microscopy (TEM) results indicate a structural variation from a monoclinic to a hexagonal structure. Raman spectra suggest a critical thickness for the structural transformation. First-principle calculations and thermodynamic analysis show that the surface energy and the interlayer interaction compete to dominate structural stability in the thinning process. A two-stage transformation process from monoclinic (m) to tetragonal (T) and then from tetragonal to hexagonal (h) is proposed to understand the phase transformation. The results demonstrate the crucial role of interlayer interactions in the structural stability, which provides a phase engineering strategy for device applications.
BackgroundCystic renal cell carcinoma (CRCC) is relatively rare; CRCC is frequently misdiagnosed as a benign renal cyst. CRCC carries an excellent prognosis following surgical treatment. The aim of our study was to summarize the management of CRCC and to characterize the prognosis of affected patients.MethodsA retrospective study of 67 patients with CRCC was conducted at our center between January 2005 and April 2013. Patient prognosis as well as the clinical manifestations, imaging characteristics, treatment, and pathologic features of CRCC were summarized based on available medical record data.ResultsWe identified 67 cases of CRCC, representing 2.5% of all renal cell carcinoma cases. The tumor was discovered incidentally in 70% of the cases. Ultrasonography was found to be a useful screening tool, but computed tomography remains the imaging study of choice for identifying malignant features. Magnetic resonance imaging can be used in equivocal cases. Regarding treatment, radical nephrectomy was performed in 52% of the cases, and partial nephrectomy was selected in the remaining 48% of cases. None of the 46 patients (68% of the study group) available for follow-up showed any evidence of recurrence.ConclusionsCRCC is an uncommon subtype of renal cell carcinoma, occurring in 2.5% of cases. CRCC carries an excellent prognosis after surgical treatment. Partial nephrectomy should be regarded as the preferred surgical technique for CRCC.
Abnormal expression of microRNAs (miRNAs) is frequently occurred in prostate cancer (PCa). This study was aimed to investigate the biological roles of miR‐451a in PCa. Quantitative real‐time PCR (qRT‐PCR) and Western blot were employed to investigate the expression levels of miR‐451a and proteasome (prosome, macropain) subunit, beta type, 8 (PSMB8) in PCa cell lines. Luciferase activity reporter assay was used to verify the connection between miR‐451a and PSMB8. in vitro functional experiments were performed to measure the effects of miR‐451a or PSMB8 on PCa cell proliferation, colony formation ability, cell invasion, and cell apoptosis. miR‐451a expression was downregulated, whereas PSMB8 expression was upregulated in PCa cell lines. Luciferase activity reporter assay confirmed the direct connection between miR‐451a and PSMB8. Overexpression of miR‐451a inhibits PCa cell proliferation, colony formation, cell invasion and promotes cell apoptosis, while the overexpression of PSMB8 caused the opposite effects. Moreover, rescue experiments confirmed PSMB8 was a functional target of miR‐451a. In conclusion, this study provides novel insights into the role of miR‐451a in PCa, and the results demonstrated miR‐451a could inhibit PCa progression by targeting PSMB8.
A novel echocardiographic method, vector flow mapping (VFM), acquires velocity vector from color Doppler velocity data. The purpose of this study was to evaluate whether VFM could provide useful information on intracardiac flow and helpful to evaluate left ventricular (LV) function. Thirty-eight patients with uremia undergoing hemodialysis and 30 healthy volunteers were enrolled. The maximum vector velocity, maximum diameter and duration of the intracardiac vortex were measured using VFM software during systole and diastole. The maximum vector velocity of the vortex and the peak velocities at the basal septum and lateral mitral annulus measured by tissue Doppler imaging (TDI) were correlated. The maximum diameter and duration of vortex formation were significantly higher in uremic patients compared with the control group during the ejection phase (40.6 ± 7.9 cm/sec vs. 28.1 ± 3.9 cm/sec; 297.1 ± 22.1 msec vs. 145.4 ± 19.3 msec, all P < 0.001). The maximal diameters of the vortex were higher in uremic patients compared with the control group during diastole (25.6 ± 3.4 mm vs. 16.4 ± 2.1 mm; 34.3 ± 3.1 mm vs. 26.8 ± 3.9 mm; 37.5 ± 2.4 mm vs. 20.9 ± 2.1 mm; all P < 0.001). The maximum vector velocities were lower in mid-diastole and late diastole (23.6 ± 2.3 cm/sec vs. 45.2 ± 3.7 cm/sec; 31.9 ± 2.9 cm/sec vs. 54.7 ± 3.2 cm/sec, all P < 0.001). There was a correlation between the maximum vector velocity of the vortex in mid-diastole and E'/A' at the septum and lateral mitral annulus (r = 0.70, r = 0.76, P < 0.001). Vortex can be utilized to provide intracardiac dynamic information using VFM and it may be a good supplement for evaluating LV function.
The effect of deep-level defects is a key issue for the applications of CdZnTe high-flux photon counting devices of X-ray irradiations. However, the major trap energy levels and their quantitive relationship with the device’s performance are not yet clearly understood. In this study, a 16-pixel CdZnTe X-ray photon counting detector with a non-uniform counting performance is investigated. The deep-level defect characteristics of each pixel region are analyzed by the current–voltage curves (I–V), infrared (IR) optical microscope photography, photoluminescence (PL) and thermally stimulated current (TSC) measurements, which indicate that the difference in counting performance is caused by the non-uniformly distributed deep-level defects in the CdZnTe crystals. Based on these results, we conclude that the CdZnTe detectors with a good photon counting performance should have a larger Te cd 2 + and Cd vacancy-related defect concentration and a lower A-center and Tei concentration. We consider the deep hole trap Tei, with the activation energy of 0.638–0.642 eV, to be the key deep-level trap affecting the photon counting performance. In addition, a theoretical model of the native defect reaction is proposed to understand the underlying relationships of resistivity, deep-level defect characteristics and photon counting performance.
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