The structure of the lithosphere-asthenosphere system is fundamental to understanding plate tectonics and Earth's evolution. Continental lithosphere, which is far more complicated than its oceanic counterpart due to the imprints left by numerous geologic processes during its long life, has drawn great attention from the seismological community (e.g.,

Significance Our regional-scale geochemical dataset ( 3 He/ 4 He) resolves the geometry of the continental collision between India and Asia. Geophysical images have led to contradictory interpretations that India directly underthrusts Tibet as a horizontal plate or India subducts steeply into the mantle. Helium transits from mantle depths to the surface within a few millennia, such that the ratio of mantle-derived 3 He to dominantly crust-derived 4 He provides a snapshot of the subsurface. 3 He/ 4 He data from 225 geothermal springs across a >1,000-km-wide region of southern Tibet define a sharp boundary subparallel to the surface suture between India and Asia, just north of the Himalaya, delineating the northern limit of India at ∼80-km depth. The India–Asia collision resembles oceanic subduction with an asthenospheric mantle wedge.

The aim of this study was to explore the expression and clinical significance of miR-494 and PTEN (phosphatase and tensin homologue deleted on chromosome ten) in non-small cell lung cancer (NSCLC). Immunohistochemistry for PTEN and in situ hybridization (ISH) for miR-494 were performed in 92 NSCLC tissues and 10 normal lung tissues to detect their expression, and correlation between their expression with clinical characteristics and prognosis was analyzed. The expression of miR-494 was significantly higher in NSCLC than in normal lung tissues (P = 0.004). The positive expression of PTEN protein in the lung carcinoma tissues was significantly lower than that in the normal lung tissues (P = 0.013), while the level of miR-494 expression was negatively correlated with PTEN expression (r = -0.577, P< 0.01). The high positive rate of miR-494 was positively correlated with pathological TNM (p-TNM) staging and lymph node metastasis. The expression of miR-494 was negatively correlated with grade of differentiation. However, the expression of PTEN was positively correlated with grade of differentiation. Patients with over-expression of miR-494 had a shorter overall survival (OS), while the negative group of PTEN was correlated with poor OS. MiR-494 over-expression and low PTEN expression are closely related to tumor p-TNM staging and lymph node metastasis, differentiation, and OS. Combined detection of PTEN and miR-494 can aid in determining malignancy degree and the prognosis of patients with NSCLC. MiR-494 may be served as a novel prognostic factor and may lead to new treatment strategies for NSCLC.