Tunable valley polarization in Janus WSSe by magnetic proximity coupling to a CrI3 layer.

We investigate the electronic properties and valley physics of Janus monolayer WSSe on a CrI3 substrate layer based on first-principles calculations. It is shown that the K and K' valley degeneracy can be lifted which leads to valley polarization (VP) in the WSSe due to the magnetic proximity coupling to a magnetic substrate. The magnitude of VP is highly sensitive to the interfacial electronic properties and can be tuned by varying the stacking configurations of the heterostructure. Interestingly, the direction of VP can be altered by manipulating the layer alignment without reversing the magnetism orientation of the magnetic substrate CrI3. We suggest that the hybridization between the bands of WSSe and the substrate plays an important role. Meanwhile, the charge distributions have been mapped out to uncover the microscopic origin of the direction variable VP. In addition, large VP can be achieved by adjusting the interlayer spacing. Our investigations may have potential applications in the design of valleytronic devices.

[Secretory carcinoma of the breast: clinical histopathologic and biological behaviors].

Objective: To investigate the clinicopathological and immunohistochemistrical features of secretory carcinoma of the breast (SCB), as well as its diagnosis and prognosis. Methods: Five cases of SCB were collected and specimens were fully drawn. Microscopic pathology examinations and immunohistochemistry(SP method)were performed. Results: Five cases were all female patients aged from 31 to 54 years old (with an average age of 38 years), and all patients initially presented with the painless breast lump, often near the areola. Macroscopically, all the tumors were relatively circumscribed, with a mean diameter of 2.1 cm(1.2-3.0 cm). Histologically, the tumors revealed different patterns (microcystic, solid, ductal, and so forth) and appeared large amounts of intracellular and extracellular eosinophilic PAS- and AB-PAS- positive secretory materials, as well as the granular eosinophilic cytoplasm. Immunohistochemistrically, the tumor cells were strongly positive for epithelial membrane antigen (EMA) and S-100. Three cases had negative expression for estrogen receptor (ER) and progesterone (PR), and two cases had weakly focal expression. Human epidermal growth factor receptor 2 (HER2) and P53 were negative, while only one case had weakly focal expression. The tumors were positive for CK7, CK5/6, CD10, but they were negative for CEA, smooth muscle actin (SMA) and P63 . The proliferation index of Ki-67 was 5%-8%. There was no patient with metastasis of the tumor in axillary lymph node. Except 1 case lost follow-up, and the rest had no recurrence or distant metastasis. Conclusions: SCB is very rare, with low malignancy, and has better prognosis, but it is usually classified as triple-negative breast cancer because of the immune phenotype. The correct diagnosis of this lesion depends on clinical characteristics, morphology and immunohistochemistry.

Phononic frequency combs through nonlinear resonances.

We explore an analogue of optical frequency combs in driven nonlinear phononic systems, and present a mechanism for generating phononic frequency combs through nonlinear resonances. In the underlying process, a set of phonon modes is simultaneously excited by the external driving which yields frequency combs with an array of discrete and equidistant spectral lines of each nonlinearly excited phonon mode. Frequency combs through nonlinear resonance of different orders are investigated, and in particular the possibility of correlation tailoring in higher-order cases is revealed. We suggest that our results can be applied in various nonlinear acoustic processes, such as phonon harvesting, and can also be generalized to other nonlinear systems.

Spin-dependent energy bands and spin polarization in two-dimensional spin-orbit lateral superlattices.

In this work, we theoretically investigate the spin-split energy bands of electrons and spin-polarized transport in two-dimensional (2D) spin-orbit lateral superlattices (SOLSLs), where the square rods with Rashba spin-orbit coupling (SOC) are distributed periodically by applying gate voltages on the semiconductor. Within the Landauer framework of ballistic transport, the energy bands, the electrical conductance, the spin polarization and the spin-dependent electronic charge distributions have been calculated. It is found that the energy minibands are formed and the energy levels are split up by the Rashba SOC. As a result, the spin-polarized conductance is obtained even in the absence of external magnetic fields and magnetic materials. Meanwhile, the spin polarization can approach high values in the SOLSLs by manipulating the strength of SOC. Furthermore, the spin-dependent electronic charge distributions have been obtained, which present a clear picture of spin-polarized conductance. Our investigations have the potential applications in spin-based quantum devices and semiconductor spintronics.