High-throughput screening of stable and efficient double inorganic halide perovskite materials by DFT.

Perovskite solar cells have become the most promising third-generation solar cells because of their superior physical-chemical properties and high photoelectric conversion efficiency. However, the current obstacles to commercialization of perovskite solar cells are their poor stability and harmful elements. How to find high-efficiency, high-stability and non-toxic perovskite materials from thousands of possible perovskite crystals is the key to solve this problem. In this paper, the inorganic halide double perovskite A2BX6 and its crystal structure are considered, and the data mining algorithm in informatics is introduced into the high-throughput computing data to analyze various elements in nature to study the perovskite materials that can meet the requirements of high performance. The photoelectric conversion properties and stability of 42 inorganic double perovskite materials are studied based on density functional theory (DFT). The results show that the tolerance factors of 39 crystals are between 0.8 and 1.10, indicating that these crystals have stable perovskite structure. In addition, the dielectric function, PDOS, elastic modulus, shear modulus and poison's ratio of these crystals are analyzed. According to the above theoretical simulation results, three candidate materials for ideal light absorption are presented. This can provide a theoretical basis for the industrial application of perovskite solar cells.

Prognostic value of survivin and EGFR protein expression in triple-negative breast cancer (TNBC) patients.

Triple-negative breast cancer (TNBC) is a particular type of breast cancer which is characterized by its biological aggressiveness, worse prognosis, and lack of prognostic markers or therapeutic targets in contrast with hormonal receptor-positive and human epidermal growth factor receptor 2-positive (HER2+) breast cancers. We aimed to evaluate survivin and epidermal growth factor receptor (EGFR) expression and their prognostic value and determine their relationships with the clinicopathological parameters of TNBC. A total of 136 patients who had undergone a resection of primary TNBC were enrolled at the Third Affiliated Hospital of Harbin Medical University from March 2003 to September 2005. Expression of ER, PR, HER2, EGFR, and survivin was assessed by immunohistochemistry. The association of TNBC and other clinicopathological variables and the prognostic value of survivin and EGFR expression were evaluated. Survivin was expressed in 62 (45.6 %) cases and EGFR was expressed in 82 (60.3 %) cases. Survivin expression was associated with menopausal status (P = 0.011), tumor size (P = 0.037), and lymph node status (P = 0.001). EGFR expression was associated with menopausal status (P = 0.029), lymph node status (P = 0.004), P53 expression (P = 0.001), Ki-67 expression (P = 0.028), and lymphatic vascular invasion (P = 0.037). A multivariate analysis demonstrated that tumor size (hazard ratio (HR) 1.587, 95 % confidence interval (CI) 1.081­2.330, P = 0.018 for disease-free survival (DFS); HR 1.606, 95%CI 1.096­2.354, P = 0.015 for overall survival (OS)), lymph node status (HR 2.873, 95%CI 1.544­5.344, P = 0.001 for DFS; HR 2.915, 95%CI 1.553­5.471, P = 0.001 for OS), tumor grade (HR 1.914, 95%CI 1.218­3.007, P = 0.005 for DFS; HR 1.983, 95%CI 1.228­3.203, P = 0.005 for OS), EGFR (HR 3.008, 95%CI 1.331­6.792, P = 0.008 for DFS; HR 3.151, 95%CI 1.374­7.226, P = 0.007 for OS), and survivin (HR 1.573, 95%CI 1.087­2.277, P = 0.016 for DFS; HR 1.607, 95%CI 1.088­2.374, P = 0.017 for OS) were of prognostic significance for disease-free and overall survival. We draw a conclusion from the present study that survivin and EGFR expression are useful prognostic markers of TNBC and might be useful for molecular targeting therapy of TNBC treatment.