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Feshbach resonances are a powerful tool to tune the interaction in an ultracold atomic gas. The commonly used magnetic Feshbach resonances are specific for each species and are restricted with respect to their temporal and spatial modulation. Optical Feshbach resonances are an alternative which can overcome this limitation. Here, we show that ultra-long-range Rydberg molecules can be used to implement an optical Feshbach resonance. Tuning the on-site interaction of a degenerate Bose gas in a 3D optical lattice, we demonstrate a similar performance compared to recent realizations of optical Feshbach resonances using intercombination transitions. Our results open up a class of optical Feshbach resonances with a plenitude of available lines for many atomic species and the possibility to further increase the performance by carefully selecting the underlying Rydberg state., Ultracold Rydberg molecules have characteristic properties that can be exploited for quantum control and applications. Here the authors demonstrate a Rydberg optical Feshbach resonance, which is based on ultra-long-range Rydberg molecules.

Funder: Max Williamson Fund, Germ cell tumours (GCTs) are a collection of benign and malignant neoplasms derived from primordial germ cells. They are uniquely able to recapitulate embryonic and extraembryonic tissues, which carries prognostic and therapeutic significance. The developmental pathways underpinning GCT initiation and histogenesis are incompletely understood. Here, we study the relationship of histogenesis and clonal diversification in GCTs by analysing the genomes and transcriptomes of 547 microdissected histological units. We find no correlation between genomic and histological heterogeneity. However, we identify unifying features including the retention of fetal developmental transcripts across tissues, expression changes on chromosome 12p, and a conserved somatic evolutionary sequence of whole genome duplication followed by clonal diversification. While this pattern is preserved across all GCTs, the developmental timing of the duplication varies between prepubertal and postpubertal cases. In addition, tumours of younger children exhibit distinct substitution signatures which may lend themselves as potential biomarkers for risk stratification. Our findings portray the extensive diversification of GCT tissues and genetic subclones as randomly distributed, while identifying overarching transcriptional and genomic features.

Malignant rhabdoid tumour (MRT) is an often lethal childhood cancer that, like many paediatric tumours, is thought to arise from aberrant fetal development. The embryonic root and differentiation pathways underpinning MRT are not firmly established. Here, we study the origin of MRT by combining phylogenetic analyses and single-cell mRNA studies in patient-derived organoids. Comparison of somatic mutations shared between cancer and surrounding normal tissues places MRT in a lineage with neural crest-derived Schwann cells. Single-cell mRNA readouts of MRT differentiation, which we examine by reverting the genetic driver mutation underpinning MRT, SMARCB1 loss, suggest that cells are blocked en route to differentiating into mesenchyme. Quantitative transcriptional predictions indicate that combined HDAC and mTOR inhibition mimic MRT differentiation, which we confirm experimentally. Our study defines the developmental block of MRT and reveals potential differentiation therapies., Malignant rhabdoid tumours (MRT) have been suggested to originate in the ectoderm-derived neural crest. Here, the authors analyse MRTs using phylogenetics, scRNA-seq, and patient-derived organoids; they find evidence for an MRT origin in the neural crest lineage and suggest differentiation treatment with HDAC/mTOR inhibitors.

Tumor cells may share some patterns of gene expression with their cell of origin, providing clues into the differentiation state and origin of cancer. Here, we study the differentiation state and cellular origin of 1300 childhood and adult kidney tumors. Using single cell mRNA reference maps of normal tissues, we quantify reference “cellular signals” in each tumor. Quantifying global differentiation, we find that childhood tumors exhibit fetal cellular signals, replacing the presumption of “fetalness” with a quantitative measure of immaturity. By contrast, in adult cancers our assessment refutes the suggestion of dedifferentiation towards a fetal state in most cases. We find an intimate connection between developmental mesenchymal populations and childhood renal tumors. We demonstrate the diagnostic potential of our approach with a case study of a cryptic renal tumor. Our findings provide a cellular definition of human renal tumors through an approach that is broadly applicable to human cancer., Transcriptomic analysis may provide information about the differentiation state and cell of origin of a cancer. Here, the authors assess mRNA signals in 1300 childhood and adult renal tumors and report a fetal origin of childhood tumors and no dedifferentiation of adult tumors.

With the emergence of applications based on short-wavelength infrared light, indium arsenide quantum dots are promising candidates to address existing shortcomings of other infrared-emissive nanomaterials. However, III–V quantum dots have historically struggled to match the high-quality optical properties of II–VI quantum dots. Here we present an extensive investigation of the kinetics that govern indium arsenide nanocrystal growth. Based on these insights, we design a synthesis of large indium arsenide quantum dots with narrow emission linewidths. We further synthesize indium arsenide-based core-shell-shell nanocrystals with quantum yields up to 82% and improved photo- and long-term storage stability. We then demonstrate non-invasive through-skull fluorescence imaging of the brain vasculature of murine models, and show that our probes exhibit 2–3 orders of magnitude higher quantum yields than commonly employed infrared emitters across the entire infrared camera sensitivity range. We anticipate that these probes will not only enable new biomedical imaging applications, but also improved infrared nanocrystal-LEDs and photon-upconversion technology., National Science Foundation (U.S.) (EECS-1449291), National Institutes of Health (U.S.) (Massachusetts Institute of Technology. Laser Biomedical Research Center. 9-P41-EB015871-26A1), Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies (W911NF-13-D-0001), Boehringer Ingelheim Fonds, European Molecular Biology Organization (Long-term Fellowship), National Science Foundation (U.S.). Graduate Research Fellowship Program, American Society for Engineering Education. National Defense Science and Engineering Graduate Fellowship, United States. Dept. of Energy. Center for Excitonics (DE- SC0001088).

Magneto-fluorescent particles have been recognized as an emerging class of materials that exhibit great potential in advanced applications. However, synthesizing such magneto-fluorescent nanomaterials that simultaneously exhibit uniform and tunable sizes, high magnetic content loading, maximized fluorophore coverage at the surface and a versatile surface functionality has proven challenging. Here we report a simple approach for co-assembling magnetic nanoparticles with fluorescent quantum dots to form colloidal magneto-fluorescent supernanoparticles. Importantly, these supernanoparticles exhibit a superstructure consisting of a close-packed magnetic nanoparticle ‘core’, which is fully surrounded by a ‘shell’ of fluorescent quantum dots. A thin layer of ​silica coating provides high colloidal stability and biocompatibility, and a versatile surface functionality. We demonstrate that after surface pegylation, these ​silica-coated magneto-fluorescent supernanoparticles can be magnetically manipulated inside living cells while being optically tracked. Moreover, our ​silica-coated magneto-fluorescent supernanoparticles can also serve as an in vivo multi-photon and magnetic resonance dual-modal imaging probe., National Institutes of Health (U.S.) (5-U54-CA151884), National Institutes of Health (U.S.) (R01-CA126642), Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies (W911NF-13-D-0001)), United States. Dept. of Energy (DE-FG02-07ER46454), National Institutes of Health (U.S.) (Massachusetts Institute of Technology. Laser Biomedical Research Center 9-P41-EB015871-26A1), United States. Dept. of Energy. Office of Basic Energy Sciences (Award DE-SC0001088), United States. Dept. of Defense (Breast Cancer Research Innovator Award W81XWH-10-1-0016)), Human Frontier Science Program (Strasbourg, France) (Grant RGP0005/2007), National Institutes of Health (U.S.) (R01-DA028299), National Institutes of Health (U.S.) (R01-NS076462), European Molecular Biology Organization (Long-term Fellowship)