Dyakonov--Tamm wave at the planar interface of a chiral sculptured thin film and an isotropic dielectric material

Surface waves, named here as Dyakonov--Tamm waves, can exist at the planar interface of an isotropic dielectric material and a chiral sculptured thin film (STF). Due to the periodic nonhomogeneity of a chiral STF, the range of the refractive index of the isotropic material is smaller but the range of the propagation direction in the interface plane is much larger, in comparison to those for the existence of Dyakonov waves at the planar interface of an isotropic dielectric material and a columnar thin film

Surface-plasmon-polariton wave propagation supported by anisotropic materials: multiple modes and mixed exponential and linear localization characteristics

The canonical boundary-value problem for surface-plasmon-polariton (SPP) waves guided by the planar interface of a dielectric material and a plasmonic material was solved for cases wherein either partnering material could be a uniaxial material with optic axis lying in the interface plane.Numerical studies revealed that two different SPP waves, with different phase speeds, propagation lengths, and penetration depths, can propagate in a given direction in the interface plane; in contrast, the planar interface of isotropic partnering materials supports only one SPP wave for each propagation direction. Also, for a unique propagation direction in each quadrant of the interface plane, it was demonstrated that a new type of SPP wave--called a surface-plasmon-polariton-Voigt (SPP-V) wave--can exist. The fields of these SPP-V waves decay as the product of a linear and an exponential function of the distance from the interface in the anisotropic partnering material; in contrast, the fields of conventional SPP waves decay only exponentially with distance from the interface. Explicit analytic solutions of the dispersion relation for SPP-V waves exist and help establish constraints on the constitutive-parameter regimes for the partnering materials that support SPP-V-wave propagation

Theory of Dyakonov-Tamm waves at the planar interface of a sculptured nematic thin film and an isotropic dielectric material

In order to ascertain conditions for surface-wave propagation guided by the planar interface of an isotropic dielectric material and a sculptured nematic thin film (SNTF) with periodic nonhomogeneity, we formulated a boundary-value problem, obtained a dispersion equation therefrom, and numerically solved it. The surface waves obtained are Dyakonov-Tamm waves. The angular domain formed by the directions of propagation of the Dyakonov--Tamm waves can be very wide (even as wide as to allow propagation in every direction in the interface plane), because of the periodic nonhomogeneity of the SNTF. A search for Dyakonov-Tamm waves is, at the present time, the most promising route to take for experimental verification of surface-wave propagation guided by the interface of two dielectric materials, at least one of which is anisotropic. That would also assist in realizing the potential of such surface waves for optical sensing of various types of analytes infiltrating one or both of the two dielectric materials.Comment: accepted for publication in J. Opt.

Retinal ganglion cell repopulation for vision restoration in optic neuropathy: a roadmap from the RReSTORe Consortium

Retinal ganglion cell (RGC) death in glaucoma and other optic neuropathies results in irreversible vision loss due to the mammalian central nervous system's limited regenerative capacity. RGC repopulation is a promising therapeutic approach to reverse vision loss from optic neuropathies if the newly introduced neurons can reestablish functional retinal and thalamic circuits. In theory, RGCs might be repopulated through the transplantation of stem cell-derived neurons or via the induction of endogenous transdifferentiation. The RGC Repopulation, Stem Cell Transplantation, and Optic Nerve Regeneration (RReSTORe) Consortium was established to address the challenges associated with the therapeutic repair of the visual pathway in optic neuropathy. In 2022, the RReSTORe Consortium initiated ongoing international collaborative discussions to advance the RGC repopulation field and has identified five critical areas of focus: (1) RGC development and differentiation, (2) Transplantation methods and models, (3) RGC survival, maturation, and host interactions, (4) Inner retinal wiring, and (5) Eye-to-brain connectivity. Here, we discuss the most pertinent questions and challenges that exist on the path to clinical translation and suggest experimental directions to propel this work going forward. Using these five subtopic discussion groups (SDGs) as a framework, we suggest multidisciplinary approaches to restore the diseased visual pathway by leveraging groundbreaking insights from developmental neuroscience, stem cell biology, molecular biology, optical imaging, animal models of optic neuropathy, immunology & immunotolerance, neuropathology & neuroprotection, materials science & biomedical engineering, and regenerative neuroscience. While significant hurdles remain, the RReSTORe Consortium's efforts provide a comprehensive roadmap for advancing the RGC repopulation field and hold potential for transformative progress in restoring vision in patients suffering from optic neuropathies

Condensin I Recruitment to Base Damage-Enriched DNA Lesions Is Modulated by PARP1

Condensin I is important for chromosome organization and segregation in mitosis. We previously showed that condensin I also interacts with PARP1 in response to DNA damage and plays a role in single-strand break repair. However, whether condensin I physically associates with DNA damage sites and how PARP1 may contribute to this process were unclear. We found that condensin I is preferentially recruited to DNA damage sites enriched for base damage. This process is dictated by PARP1 through its interaction with the chromosome-targeting domain of the hCAP-D2 subunit of condensin I

Decadal predictions with the HiGEM high resolution global coupled climate model: description and basic evaluation

This paper describes the development and basic evaluation of decadal predictions produced using the HiGEM coupled climate model. HiGEM is a higher resolution version of the HadGEM1 Met Office Unified Model. The horizontal resolution in HiGEM has been increased to 1.25◦ × 0.83◦ in longitude and latitude for the atmosphere, and 1/3◦ × 1/3◦ globally for the ocean. The HiGEM decadal predictions are initialised using an anomaly assimilation scheme that relaxes anomalies of ocean temperature and salinity to observed anomalies. 10 year hindcasts are produced for 10 start dates (1960, 1965,..., 2000, 2005). To determine the relative contributions to prediction skill from initial conditions and external forcing, the HiGEM decadal predictions are compared to uninitialised HiGEM transient experiments. The HiGEM decadal predictions have substantial skill for predictions of annual mean surface air temperature and 100 m upper ocean temperature. For lead times up to 10 years, anomaly correlations (ACC) over large areas of the North Atlantic Ocean, the Western Pacific Ocean and the Indian Ocean exceed values of 0.6. Initialisation of the HiGEM decadal predictions significantly increases skill over regions of the Atlantic Ocean,the Maritime Continent and regions of the subtropical North and South Pacific Ocean. In particular, HiGEM produces skillful predictions of the North Atlantic subpolar gyre for up to 4 years lead time (with ACC > 0.7), which are significantly larger than the uninitialised HiGEM transient experiments

Instrumental methods and challenges in quantifying polybrominated diphenyl ethers in environmental extracts: a review

Increased interest in the fate, transport and toxicity of polybrominated diphenyl ethers (PBDEs) over the past few years has led to a variety of studies reporting different methods of analysis for these persistent organic pollutants. Because PBDEs encompass a range of vapor pressures, molecular weights and degrees of bromine substitution, various analytical methods can lead to discrimination of some PBDE congeners. Recent improvements in injection techniques and mass spectrometer ionization methods have led to a variety of options to determine PBDEs in environmental samples. The purpose of this paper is therefore to review the available literature describing the advantages and disadvantages in choosing an injection technique, gas chromatography column and detector. Additional discussion is given to the challenges in measuring PBDEs, including potential chromatographic interferences and the lack of commercial standards for higher brominated congeners, which provides difficulties in examining degradation and debromination of BDE congeners, particularly for BDE 209

A genome-wide screening uncovers the role of CCAR2 as an antagonist of DNA end resection

There are two major and alternative pathways to repair DNA double-strand breaks: non-homologous end-joining and homologous recombination. Here we identify and characterize novel factors involved in choosing between these pathways; in this study we took advantage of the SeeSaw Reporter, in which the repair of double-strand breaks by homology-independent or -dependent mechanisms is distinguished by the accumulation of green or red fluorescence, respectively. Using a genome-wide human esiRNA (endoribonuclease- prepared siRNA) library, we isolate genes that control the recombination/endjoining ratio. Here we report that two distinct sets of genes are involved in the control of the balance between NHEJ and HR: those that are required to facilitate recombination and those that favour NHEJ. This last category includes CCAR2/DBC1, which we show inhibits recombination by limiting the initiation and the extent of DNA end resection, thereby acting as an antagonist of CtIP