Upregulation of Src homology phosphotyrosyl phosphatase 2 (Shp2) expression in oral cancer and knockdown of Shp2 expression inhibit tumor cell viability and invasion in vitro

ObjectiveThis study investigated the clinical significance of Shp2 protein expression in oral squamous cell carcinoma (OSCC) and elucidated its biologic significance in OSCC cells.Study DesignA total of 88 OSCC cases were used to assess Shp2 expression, out of which 70 were for immunohistochemistry and 18 paired tumors vs normal tissues were for Western blot of Shp2 expression. OSCC cells were used to assess the effects of Shp2 knockdown for cell viability, apoptosis, invasion, and protein expressions.ResultsExpression of Shp2 protein was significantly upregulated in OSCC tissues compared with the normal tissues, and Shp2 overexpression was associated with advanced tumor clinical stages and lymph node metastasis ex vivo. Knockdown of Shp2 expression in vitro inhibited OSCC cell viability and invasion but induced apoptosis by regulating expression of the apoptosis-related proteins.ConclusionsThe data indicated that Shp2 may play an important role in OSCC progression. Further studies will investigate whether a target of Shp2 expression could be a novel therapeutic strategy for clinical control of OSCC

Topological interfacial states in ferroelectric domain walls of two-dimensional bismuth

Using machine learning method, we investigate various domain walls for the recently discovered single-element ferroelectrics bismuth monolayer [Nature 617, 67 (2023)]. Surprisingly, we find that the charged domain wall configuration has a lower energy than the uncharged domain wall structure due to its low electrostatic repulsion potential. Two stable charged domain wall configurations exhibit topological interfacial states near their domain walls, which is caused by the change of the Z_2 number between ferroelectric and paraelectric states. Interestingly, different from the edge states of topological insulators, the topological interfacial states related Dirac bands are contributed from different edges which is caused by the build-in electric field of FE. Our works thus indicate that domain walls in two-dimensional bismuth can be a good platform for ferroelectric domain wall devices.Comment: 15 pages, 4 fig

Study on Failure Length of Cementing Interface in Horizontal Wells During Fracturing

The cementing interface of oil and gas wells is often the weak link between oil and gas turbulence. Due to the low cementation strength at the fracturing interface, the two interfaces have been crushed to form turbulence channels before the target layer is opened during fracturing. If the closure is not good, there will be inter-layer channeling. Therefore, the pressure bearing capacity of the fracturing interface is an important indicator for designing the fracturing construction parameters. The pressure capacity of the two interfaces during the fracturing process is the key to evaluating the success of the fracturing construction. This paper establishes the calculation model for the stress distribution of horizontal wells in horizontal wells under the effect of non-uniform stress. At the same time, the influence of the pressure change in the wellbore during the fracturing process on the stress distribution in the borehole wall was analyzed. The calculation model of the interfacial stress distribution in the horizontal well during the fracturing process was established, and the debonding pressure and debonding length of the two interfaces under different cementing strengths were calculated. After the establishment of the horizontal well fracturing two interface crack propagation mechanics model, calculate the pressure required for cracks along the two interfaces to expand at different failure lengths

Easy Begun is Half Done: Spatial-Temporal Graph Modeling with ST-Curriculum Dropout

Spatial-temporal (ST) graph modeling, such as traffic speed forecasting and taxi demand prediction, is an important task in deep learning area. However, for the nodes in graph, their ST patterns can vary greatly in difficulties for modeling, owning to the heterogeneous nature of ST data. We argue that unveiling the nodes to the model in a meaningful order, from easy to complex, can provide performance improvements over traditional training procedure. The idea has its root in Curriculum Learning which suggests in the early stage of training models can be sensitive to noise and difficult samples. In this paper, we propose ST-Curriculum Dropout, a novel and easy-to-implement strategy for spatial-temporal graph modeling. Specifically, we evaluate the learning difficulty of each node in high-level feature space and drop those difficult ones out to ensure the model only needs to handle fundamental ST relations at the beginning, before gradually moving to hard ones. Our strategy can be applied to any canonical deep learning architecture without extra trainable parameters, and extensive experiments on a wide range of datasets are conducted to illustrate that, by controlling the difficulty level of ST relations as the training progresses, the model is able to capture better representation of the data and thus yields better generalization

Biomaterials with structural hierarchy and controlled 3D nanotopography guide endogenous bone regeneration

Biomaterials without exogenous cells or therapeutic agents often fail to achieve rapid endogenous bone regeneration with high quality. Here, we reported a class of three-dimensional (3D) nanofiber scaffolds with hierarchical structure and controlled alignment for effective endogenous cranial bone regeneration. 3D scaffolds consisting of radially aligned nanofibers guided and promoted the migration of bone marrow stem cells from the surrounding region to the center in vitro. These scaffolds showed the highest new bone volume, surface coverage, and mineral density among the tested groups in vivo. The regenerated bone exhibited a radially aligned fashion, closely recapitulating the scaffold’s architecture. The organic phase in regenerated bone showed an aligned, layered, and densely packed structure, while the inorganic mineral phase showed a uniform distribution with smaller pore size and an even distribution of stress upon the simulated compression. We expect that this study will inspire the design of next-generation biomaterials for effective endogenous bone regeneration with desired quality

Direct observation of Si-related and Ge-related ring clusters on Si(1 1 1)-(7 Â 7) surface

Abstract In a scanning tunnelling microscope (STM) study of Si(1 1 1)-(7 Â 7) surfaces, we observed the Si-related ring cluster and one new type of Ge-related ring cluster. For both clusters there is an electron transfer between them and the nearby Si centre atoms and their local density of states near the Fermi level is obviously reduced. Moreover, by differences in their electron transfer, the Si-related ring cluster and Ge-related ring cluster can be easily distinguished from each other.

Observation of intervalley quantum interference in epitaxial monolayer WSe2

Monolayer (ML) transition metal dichalcogenides (TMDs) have been attracting great research attentions lately for their extraordinary properties, in particular the exotic spin-valley coupled electronic structures that promise future spintronic and valleytronic applications1-3. The energy bands of ML TMDs have well separated valleys that constitute effectively an extra internal degree of freedom for low energy carriers3-12. The large spin-orbit coupling in the TMDs makes the spin index locked to the valley index, which has some interesting consequences such as the magnetoelectric effects in 2H bilayers13. A direct experimental characterization of the spin-valley coupled electronic structure can be of great interests for both fundamental physics and device applications. In this work, we report the first experimental observation of the quasi-particle interference (QPI) patterns in ML WSe2 using low-temperature (LT) scanning tunneling microscopy/spectroscopy (STM/S). We observe intervalley quantum interference involving the Q-valleys in the conduction band due to spin-conserved scattering processes, while spin-flip intervalley scattering is absent. This experiment establishes unequivocally the presence of spin-valley coupling and affirms the large spin-splitting at the Q valleys. Importantly, the inefficient spin-flip intervalley scattering implies long valley and spin lifetime in ML WSe2, which represents a key figure of merit for valley-spintronic applications.Comment: 15 pages, 4 figure

Dense network of one-dimensional mid-gap metallic modes in monolayer MoSe2 and their spatial undulations

We report the observation of a dense triangular network of one-dimensional (1D) metallic modes in a continuous and uniform monolayer of MoSe2 grown by molecular-beam epitaxy. High-resolution transmission electron microscopy and scanning tunneling microscopy and spectroscopy (STM/STS) studies show these 1D modes are mid-gap states at inversion domain boundaries. STM/STS measurements further reveal intensity undulations of the metallic modes, presumably arising from the superlattice potentials due to moire pattern and the quantum confinement effect. A dense network of the metallic modes with high density of states is of great potential for heterocatalysis applications. The interconnection of such mid-gap 1D conducting channels may also imply new transport behaviors distinct from the 2D bulk