Colloidal Synthesis of (PbBr₂)₂(AMTP)₂PbBr₄ a Periodic Perovskite “Heterostructured” Nanocrystal

Heterostructures in nanoparticles challenge our common understanding of interfaces due to quantum confinement and size effects, giving rise to synergistic properties. An alternating heterostructure in which multiple and reoccurring interfaces appear in a single nanocrystal is hypothesized to accentuate such properties. We present a colloidal synthesis for perovskite layered heterostructure nanoparticles with a (PbBr2)2(AMTP)2PbBr4 composition. By varying the synthetic parameters, such as synthesis temperature, solvent, and selection of precursors, we control particle size, shape, and product priority. The structures are validated by X-ray and electron diffraction techniques. The heterostructure nanoparticles’ main optical feature is a broad emission peak, showing the same range of wavelengths compared to the bulk sample

A single cell atlas of the human liver tumor microenvironment

Abstract Malignant cell growth is fueled by interactions between tumor cells and the stromal cells composing the tumor microenvironment. The human liver is a major site of tumors and metastases, but molecular identities and intercellular interactions of different cell types have not been resolved in these pathologies. Here, we apply single cell RNA‐sequencing and spatial analysis of malignant and adjacent non‐malignant liver tissues from five patients with cholangiocarcinoma or liver metastases. We find that stromal cells exhibit recurring, patient‐independent expression programs, and reconstruct a ligand–receptor map that highlights recurring tumor–stroma interactions. By combining transcriptomics of laser‐capture microdissected regions, we reconstruct a zonation atlas of hepatocytes in the non‐malignant sites and characterize the spatial distribution of each cell type across the tumor microenvironment. Our analysis provides a resource for understanding human liver malignancies and may expose potential points of interventions

How Does Local Strain Affect Stokes Shifts in Halide Double Perovskite Nanocrystals?

Lead-free perovskite nanocrystals are of interest due to their nontoxicity and potential application in the display industry. However, engineering their optical properties is nontrivial and demands an understanding of emission from both self-trapped and free excitons. Here, we focus on tuning silver-based double perovskite nanocrystals' optical properties via two iso-valent dopants, Bi and Sb. The photoluminescence quantum yield of the intrinsic Cs2Ag1-yNayInCl6 perovskite increased dramatically upon doping. However, the two dopants affect the optical properties very differently. We hypothesize that the differences arise from their differences in electronic level contributions and ionic sizes. This hypothesis is validated through absorption and temperature dependence photoluminescence measurements, namely, by employing the Huang-Rhys factor, which indicates the coupling of the exciton to the lattice environment. The larger ionic size of Bi also plays a role in inducing significant microstraining verified via synchrotron measurements. These differences make Bi more sensitive to doping concentration over antimony which displays brighter emission (QY ∼40%). Such understanding is important for engineering optical properties in double perovskites, especially in light of recent achievements in boosting the photoluminescence quantum yield

TAp73 is downregulated in oocytes from women of advanced reproductive age

Studies on oocyte transcriptome are important to understand the biological pathways involved in oogenesis, totipotence and early embryonic development. Moreover, genes regulating physiological pathways in gametes could represent potential candidates for reproductive disorders. In addition to oocyte specific transcription factors, also the members of the p53 family could be etiologically involved due to their biological functions. In fact, their role in the control of cell cycle, apoptosis and germ-line genome stability is well known. Female reproductive aging is one of the causes of fertility reduction and it is often associated with egg aneuploidy increase. In order to verify the potential involvement of p73 in reproductive aging, we determined its expression in single mature MII oocytes from two groups of women, younger than 35 or older than 38 y, respectively. We found that TAp73 isoforms are downregulated in oocytes from women older than 38 y. We confirmed these data in pools of mouse oocytes. TAp73 downregulation in oocytes from women of advanced reproductive age could explain both the reduction of fertility and the increase of newborns with chromosomal abnormalities