The role of losses in determining hyperbolic material figures of merit.

Uniaxial materials have achieved new prominence in photonics because they can have hyperbolic spectral regions with metallic (ε<0) and dielectric (ε>0) permittivities along different crystal axes. In the lossless case, this results in an open hyperboloid dispersion relation, allowing materials to support highly confined modes with extremely large wavevectors. However, even small losses change the character of the hyperbolic dispersion from open hyperboloids to closed surfaces with finite maximum k, significantly limiting the extent to which highly-confined modes can be achieved.

Near-Unity Light-Matter Interaction in Mid-Infrared van der Waals Metasurfaces.

Accessing mid-infrared radiation is of great importance for a range of applications, including thermal imaging, sensing, and radiative cooling. Here, we study light interaction with hexagonal boron nitride (hBN) nanocavities and reveal strong and tunable resonances across its hyperbolic transition. In addition to conventional phonon-polariton excitations, we demonstrate that the high refractive index of hexagonal boron nitride outside the Reststrahlen band allows enhanced light-matter interactions in deep subwavelength (<λ/15) nanostructures across a broad 7-8 μm range.

FLIP(C1orf112)-FIGNL1 complex regulates RAD51 chromatin association to promote viability after replication stress.

Homologous recombination (HR) plays critical roles in repairing lesions that arise during DNA replication and is thus essential for viability. RAD51 plays important roles during replication and HR, however, how RAD51 is regulated downstream of nucleofilament formation and how the varied RAD51 functions are regulated is not clear. We have investigated the protein c1orf112/FLIP that previously scored in genome-wide screens for mediators of DNA inter-strand crosslink (ICL) repair.

Fluorene-9-bisphenol affects the terminal differentiation of mouse embryonic bodies.

Fluorene-9-bisphenol (BHPF) has recently attracted interest as it is increasingly used in industrial settings as a substitute for Bisphenol A (BPA). However, the effects of BHPF exposure on embryonic stem cell (ESC) self-renewal, pluripotency, and differentiation remain poorly understood. This study investigates the impacts of BHPF on mouse embryonic stem cells (mESCs) and embryonic bodies (EBs).

RADIF(C1orf112)-FIGNL1 Complex Regulates RAD51 Chromatin Association to Promote Viability After Replication Stress.

Homologous recombination (HR) plays critical roles in repairing lesions that arise during DNA replication and is thus essential for viability. RAD51 plays important roles during replication and HR, however, how RAD51 is regulated downstream of nucleofilament formation and how the varied RAD51 functions are regulated is not clear. We have investigated the poorly characterized protein c1orf112/RADIF that previously scored in genome-wide screens for mediators of DNA inter-strand crosslink (ICL) repair.

Mapping nanocrystal orientations via scanning Laue diffraction microscopy for multi-peak Bragg coherent diffraction imaging.

The recent commissioning of a movable monochromator at the 34-ID-C endstation of the Advanced Photon Source has vastly simplified the collection of Bragg coherent diffraction imaging (BCDI) data from multiple Bragg peaks of sub-micrometre scale samples. Laue patterns arising from the scattering of a polychromatic beam by arbitrarily oriented nanocrystals permit their crystal orientations to be computed, which are then used for locating and collecting several non-co-linear Bragg reflections. The volumetric six-component strain tensor is then constructed by combining the projected displacement fields that are imaged using each of the measured reflections via iterative phase retrieval algorithms.

Digital autofocusing of a coded-aperture Laue diffraction microscope.

To provide optimal depth resolution with a coded-aperture Laue diffraction microscope, an accurate position of the coded-aperture and its scanning geometry need to be known. However, finding the geometry by trial and error is a time-consuming and often challenging process because of the large number of parameters involved. In this paper, we propose an optimization approach to automate the focusing process after data is collected.

Erratum: An automated do-it-yourself system for dynamic stem cell and organoid culture in standard multi-well plates.

[This corrects the article DOI: 10.1016/j.crmeth.

Examining African contributions to global health: Reflections on knowledge circulation and innovation.

This article unites different disciplinary debates on 'southern innovation', 'theory from the South', and 'decolonisation of knowledge' in order to discuss existing understandings around the role of Africa in the production of health-related knowledge, public health policy, and medical innovation. Arguing that high-income countries have much to learn from the global South when it comes to health-related knowledge and practices, we propose an interdisciplinary research approach to uncovering and examining African contributions to global health, drawing on an ongoing collaborative project funded by the Swiss National Science Foundation. We present four empirical case studies concerning drug development, healthcare systems, and urban planning to critically enquire into both historical and contemporary transcontinental knowledge circulation and learning potentials, as much as cases of forgetting and silencing.

An automated do-it-yourself system for dynamic stem cell and organoid culture in standard multi-well plates.

We present a low-cost, do-it-yourself system for complex mammalian cell culture under dynamically changing medium formulations by integrating conventional multi-well tissue culture plates with simple microfluidic control and system automation. We demonstrate the generation of complex concentration profiles, enabling the investigation of sophisticated input-response relations. We further apply our automated cell-culturing platform to the dynamic stimulation of two widely employed stem-cell-based models for early mammalian development: the conversion of naive mouse embryonic stem cells into epiblast-like cells and mouse 3D gastruloids.

Enhanced Infrared Photodiodes Based on PbS/PbCl Core/Shell Nanocrystals.

Improved passivation strategies to address the more complex surface structure of large-diameter nanocrystals are critical to the advancement of infrared photodetectors based on colloidal PbS. In this contribution, the performance of short-wave infrared (SWIR) photodiodes fabricated with PbS/PbCl (core/shell) nanocrystals vs their PbS-only (core) counterparts are directly compared. Devices using PbS cores suffer from shunting and inefficient charge extraction, while core/shell-based devices exhibit greater external quantum efficiencies and lower dark current densities.

Discovery of davemaoite, CaSiO-perovskite, as a mineral from the lower mantle.

Calcium silicate perovskite, CaSiO, is arguably the most geochemically important phase in the lower mantle, because it concentrates elements that are incompatible in the upper mantle, including the heat-generating elements thorium and uranium, which have half-lives longer than the geologic history of Earth. We report CaSiO-perovskite as an approved mineral (IMA2020-012a) with the name davemaoite. The natural specimen of davemaoite proves the existence of compositional heterogeneity within the lower mantle.

Tunable side-bounce monochromator.

Side-bounce beamlines with fixed-exit angles have been intended to operate with only one selected energy. However, a tunable monochromator in a new geometry is presented here that will make side-bounce beamlines energy tunable. It requires the addition of two more rotations.

Plasmonic nanoarcs: a versatile platform with tunable localized surface plasmon resonances in octave intervals.

The tunability of the longitudinal localized surface plasmon resonances (LSPRs) of metallic nanoarcs is demonstrated with key relationships identified between geometric parameters of the arcs and their resonances in the infrared. The wavelength of the LSPRs is tuned by the mid-arc length of the nanoarc. The ratio between the attenuation of the fundamental and second order LSPRs is governed by the nanoarc central angle.

Combining Laue diffraction with Bragg coherent diffraction imaging at 34-ID-C.

Measurement modalities in Bragg coherent diffraction imaging (BCDI) rely on finding a signal from a single nanoscale crystal object which satisfies the Bragg condition among a large number of arbitrarily oriented nanocrystals. However, even when the signal from a single Bragg reflection with (hkl) Miller indices is found, the crystallographic axes on the retrieved three-dimensional (3D) image of the crystal remain unknown, and thus localizing in reciprocal space other Bragg reflections becomes time-consuming or requires good knowledge of the orientation of the crystal. Here, the commissioning of a movable double-bounce Si (111) monochromator at the 34-ID-C endstation of the Advanced Photon Source is reported, which aims at delivering multi-reflection BCDI as a standard tool in a single beamline instrument.

Binary Superlattices of Infrared Plasmonic and Excitonic Nanocrystals.

Self-assembled superlattices of nanocrystals offer exceptional control over the coupling between nanocrystals, similar to how solid-state crystals tailor the bonding between atoms. By assembling nanocrystals of different properties (e.g.

Cases in Precision Medicine: The Role of Tumor and Germline Genetic Testing in Breast Cancer Management.

Personalization of care through precision medicine and, more specifically, genetic testing is altering the treatment of breast cancer. Genetic testing is used in germline and tumor testing, with each providing distinct data to guide management. Germline testing supports more accurate risk evaluation to inform screening and risk-reducing medical and surgical strategies.

Experimental setup combining in situ hard X-ray photoelectron spectroscopy and real-time surface X-ray diffraction for characterizing atomic and electronic structure evolution during complex oxide heterostructure growth.

We describe the next-generation system for in situ characterization of a complex oxide thin film and heterostructure growth by pulsed laser deposition (PLD) using synchrotron hard X-rays. The system consists of a PLD chamber mounted on a diffractometer allowing both real-time surface X-ray diffraction (SXRD) and in situ hard X-ray photoelectron spectroscopy (HAXPES). HAXPES is performed in the incident X-ray energy range from 4 to 12 keV using a Scienta EW4000 electron energy analyzer mounted on the PLD chamber fixed parallel with the surface normal.

Author Correction: Ultralow-loss polaritons in isotopically pure boron nitride.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Controlling dissolution of PbTe nanoparticles in organic solvents during liquid cell transmission electron microscopy.

We present direct visualization of the dynamics of oleic-acid-capped PbTe nanoparticles suspended in different organic solvents using liquid cell transmission electron microscopy. Liquid cell transmission electron microscopy is a powerful tool to directly observe the behavior of a variety of nanoparticles in liquids, but requires careful consideration and quantification of how the electron beam affects the systems being investigated. We find that etching and dissolution of PbTe nanoparticles occurs with a strong dependence on electron dose rate ranging from no perceivable effect on the nanoparticles with lower dose rates (50 e- Å-2 s-1) to complete dissolution within seconds or minutes at higher dose rates (100 and 200 e- Å-2 s-1).

Hybrid longitudinal-transverse phonon polaritons.

Phonon polaritons, hybrid light-matter quasiparticles resulting from strong coupling of the electromagnetic field with the lattice vibrations of polar crystals are a promising platform for mid-infrared photonics but for the moment there has been no proposal allowing for their electrical pumping. Electrical currents in fact mainly generate longitudinal optical phonons, while only transverse ones participate in the creation of phonon polaritons. We demonstrate how to exploit long-cell polytypes of silicon carbide to achieve strong coupling between transverse phonon polaritons and zone-folded longitudinal optical phonons.

Effects of a Lead Chloride Shell on Lead Sulfide Quantum Dots.

The size of a quantum-confined nanocrystal determines the energies of its excitonic transitions. Previous work has correlated the diameters of PbS nanocrystals to their excitonic absorption; however, we observe that PbS quantum dots synthesized in saturated dispersions of PbCl can deviate from the previous 1S-1S energy vs diameter curve by 0.8 nm.

Implementation of plasmonic band structure to understand polariton hybridization within metamaterials.

Gap surface plasmons (GSPs) serve a diverse range of plasmonic applications, including energy harvesting, communications, molecular sensing, and optical detection. GSPs may be realized where tightly spaced plasmonic structures exhibit strong spatial overlap between the evanescent fields. We demonstrate that within similar, nested geometries that the near-fields of the GSPs within the individual nanostructures are hybridized.