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Epitaxial layers of PbSe have been grown onto Si(111) by vacuum deposition techniques using a (Ca, Ba)F[sub 2] buffer film. For lattice match, the buffer layer is graded with CaF[sub 2] at the Si interface and BaF[sub 2] at the PbSe interface. Like bulk BaF[sub 2], this buffer layer forms a suitable support for the growth of high quality PbSe. The layers grown exhibit smooth surfaces and mobilities as high as those of bulk PbSe, i.e., ˜3 × 10[sup 4] cm[sup 2] V[sup -1] s[sup -1] at 77 K and >1.2 × 10[sup 5] cm² V[sup -1] s[sup -1] below 20 K. These results are very promising for the fabrication of heteroepitaxial monolithic integrated circuits, with, for example, photovoltaic (Pb,Sn) (S,Se,Te) narrow gap semiconductor infrared detectors on silicon. [ABSTRACT FROM AUTHOR]

Self-renewal programs in leukemia stem cells (LSCs) predict poor prognosis in patients with acute myeloid leukemia (AML). We identify CD4 + T cell-derived interleukin (IL)-21 as an important negative regulator of self-renewal of LSCs. IL-21/IL-21R signaling favors asymmetric cell division and differentiation in LSCs through the activation of p38-MAPK signaling, resulting in reduced LSC numbers and significantly prolonged survival in murine AML models. In human AML, serum IL-21 at diagnosis is identified as an independent positive prognostic biomarker for outcome and correlates with improved survival and higher complete remission rates in patients that underwent high-dose chemotherapy. IL-21 treatment inhibits primary LSC function and enhances the effect of cytarabine and CD70 CAR T cell treatment on LSCs in vitro. Low-dose IL-21 treatment prolongs the survival of AML mice in syngeneic and xenograft experiments. Therefore, promoting IL-21/IL-21R signaling on LSCs may be an approach to reduce stemness and increase differentiation in AML., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)