Groundwater sapping as the cause of irreversible desertification of Hunshandake Sandy Lands, Inner Mongolia, northern China.

In the middle-to-late Holocene, Earth's monsoonal regions experienced catastrophic precipitation decreases that produced green to desert state shifts. Resulting hydrologic regime change negatively impacted water availability and Neolithic cultures. Whereas mid-Holocene drying is commonly attributed to slow insolation reduction and subsequent nonlinear vegetation-atmosphere feedbacks that produce threshold conditions, evidence of trigger events initiating state switching has remained elusive. Here we document a threshold event ca. 4,200 years ago in the Hunshandake Sandy Lands of Inner Mongolia, northern China, associated with groundwater capture by the Xilamulun River. This process initiated a sudden and irreversible region-wide hydrologic event that exacerbated the desertification of the Hunshandake, resulting in post-Humid Period mass migration of northern China's Neolithic cultures. The Hunshandake remains arid and is unlikely, even with massive rehabilitation efforts, to revert back to green conditions.

SLL-1A-16 suppresses proliferation and induces autophagy in non-small-cell lung cancer cells via the AKT/mTOR signaling pathway.

Non-small-cell lung cancer (NSCLC), which accounts for approximately eighty-five percent of lung cancer diagnoses worldwide, is a malignancy with high incidence and mortality rates. Among the various antitumor compounds, organic selenium-containing compounds have emerged as a promising class of therapeutic agents for cancer treatment. In the present study, SLL-1A-16, a new organoselenium small molecule, was discovered to exhibit antiproliferative activity against NSCLC both in vitro and in vivo. Treatment with SLL-1A-16 significantly inhibited NSCLC cell proliferation and induced apoptosis and autophagy. Mechanistically, SLL-1A-16 inhibited cell proliferation through G1-S phase arrest by reducing cyclin D1 and CDK4 expression. Additionally, SLL-1A-16 significantly induced apoptosis by upregulating cleaved caspase 3 and Bax expression, while downregulating Bcl-2 levels. Our study also demonstrated that SLL-1A-16 induced autophagy in NSCLC cells by inhibiting the Akt/mTOR pathway. Overall, our findings suggest that SLL-1A-16 could induce cell cycle arrest, apoptosis and autophagy in NSCLC cells by inhibiting the Akt/mTOR signaling pathways, providing a theoretical basis for the potential clinical application of SLL-1A-16 as a chemotherapeutic agent in NSCLC treatment.