CD163 interacts with TWEAK to regulate tissue regeneration after ischaemic injury

biological sciences, medical researc

Circular dichroism of designed peptide helices and β-hairpins: analysis of trp- and tyr-rich peptides

VCD versus ECD spectroscopy. Peptides rich in aromatic residues yield anomalous far-UV electronic circular dichroism (ECD) spectra that preclude secondary structure assignment. The utility of vibrational circular dichroism (VCD) in conformation analysis is demonstrated by using a set of well-defined peptide helices and hairpins containing proximal aromatic residues

Enhanced optical activity using the orbital angular momentum of structured light

Recent molecular photonics studies have highlighted the significant role that phase-structured light possessing orbital angular momentum (OAM) can have when interacting with matter. These studies discovered chiroptical effects sensitive to both the magnitude and sign of the optical OAM in both the absorption and scattering of twisted photons by molecules and nanoparticles. Specifically, it has been shown how a structured beam engaging with electric-quadrupole transitions in the material allows a unique sensitivity to the helical-phase structure of twisted light. In this paper we highlight experimental methodologies and systems suitable to observe and quantify the chiroptical processes of Rayleigh and Raman optical activity, and the newly discovered circular-vortex differential scattering effect with structured light—including the importance of off-axis beam alignment, input beam intensity structure, multipolar moments, and scattering-angle dependencies. It is shown that with a judicious choice of experimental setup, chiroptical effects that scale with the topological charge or OAM of the input beam enable optical activity signals to be enhanced and significantly exceed those based solely on circularly polarized, unstructured light. The new technique thus offers a highly useful and important spectroscopic application of structured light. The more detailed role that perfect optical vortices with high OAM will play in such optical activity effects is now highlighted, to show where there is substantial scope for experimental application, specifically in vibrational optical activity and chiral spectroscopy

Point source generation of chiral fields:measures of near- and far-field optical helicity

To consider the relationship between different measures of chirality in an optical field, the simplest case is considered: direct spontaneous emission of circularly polarized light by a point source. In the electromagnetic fields radiated from a suitably chiral source, such as a low-symmetry chiral molecule undergoing radiative decay, optical helicity is exhibited in the extent of a difference in left- and right-handed circular polarization components. There are several practical measures for quantifying the emergence of ensuing optical helicity, exhibiting different forms of dependence on the properties of the emitter and the positioning of a detector. By casting each measure in terms of an irreducible helicity density, connections and distinctions can be drawn between results expressible in either classical or quantum form

Arginine Reverses Ethanol-Induced Inflammatory and Fibrotic changes in Liver despite continued Ethanol Administration

We investigated the potential of arginine to reverse pathological changes in alcohol-induced liver injury. Four groups (six rats/group) of male Wistar rats were fed a fish oil-ethanol diet for 6 (group 2) or 8 (group 1) weeks. Rats in group 3 were fed fish oil-ethanol for 6 weeks, after which they were administered arginine with fish oil-ethanol for an additional 2 weeks. Rats in group 4 were fed fish oil-dextrose for 8 weeks. Liver samples were analyzed for histopathology, lipid peroxidation, cytochrome P4502E1 activity, nuclear factor-κB, and levels of messenger RNA for tumor necrosis factor-α, cyclooxygenase-2, and inducible nitric oxide synthase. Concentrations of endotoxin were measured in plasma. The most severe inflammation and fibrosis was detected in groups 1 and 2, as were the highest levels of endotoxin, lipid peroxidation, cytochrome P450 2E1 activity, activation of nuclear factor-κB, and mRNA levels for tumor necrosis factor-α, cyclooxygenase-2, and inducible nitric oxide synthase. Plasma nitric oxide was also increased as was nitrotyrosine in liver. After arginine was administered, there was marked improvement in the pathological changes accompanied by decreased levels of endotoxin, lipid peroxidation, activation of nuclear factor-κB, tumor necrosis factor-α, cyclooxygenase-2, inducible nitric oxide, and nitrotyrosine staining. The therapeutic effects of arginine are probably secondary to increased levels of nitric oxide but other effects of arginine cannot be excluded

Fast A‐site cation cross‐exchange at room temperature: single‐to double‐ and triple‐cation halide perovskite nanocrystals

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGWe report here fast A-site cation cross-exchange between APbX3 perovskite nanocrystals (NCs) made of different A-cations (Cs (cesium), FA (formamidinium), and MA (methylammonium)) at room temperature. Surprisingly, the A-cation cross-exchange proceeds as fast as the halide (X=Cl, Br, or I) exchange with the help of free A-oleate complexes present in the freshly prepared colloidal perovskite NC solutions. This enabled the preparation of double (MACs, MAFA, CsFA)- and triple (MACsFA)-cation perovskite NCs with an optical band gap that is finely tunable by their A-site composition. The optical spectroscopy together with structural analysis using XRD and atomically resolved high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and integrated differential phase contrast (iDPC) STEM indicates the homogeneous distribution of different cations in the mixed perovskite NC lattice. Unlike halide ions, the A-cations do not phase-segregate under light illumination.Agencia Estatal de Investigación https://doi.org/10.13039/501100011033 | Ref. PID2020-117371RA-I00Xunta de Galicia https://doi.org/10.13039/501100010801 | Ref. ED431F2021/05HORIZON EUROPE European Research Council https://doi.org/10.13039/100019180 | Ref. ERC-CoG-2019 815128European Commission https://doi.org/10.13039/501100000780 | Ref. 731019Engineering and Physical Sciences Research Council https://doi.org/10.13039/501100000266 | Ref. EP/R023980/1Royal Society https://doi.org/10.13039/50110000028

Application of time-dependent density functional theory to optical activity

As part of a general study of the time-dependent local density approximation (TDLDA), we here report calculations of optical activity of chiral molecules. The theory automatically satisfies sum rules and the Kramers-Kronig relation between circular dichroism and optical rotatory power. We find that the theory describes the measured circular dichroism of the lowest states in methyloxirane with an accuracy of about a factor of two. In the chiral fullerene C_76 the TDLDA provides a consistent description of the optical absorption spectrum, the circular dichroism spectrum, and the optical rotatory power, except for an overall shift of the theoretical spectrum.Comment: 17 pages and 13 PostScript figure

Identifying and Reducing Interfacial Losses to Enhance Color-Pure Electroluminescence in Blue-Emitting Perovskite Nanoplatelet Light-Emitting Diodes.

Perovskite nanoplatelets (NPls) hold promise for light-emitting applications, having achieved photoluminescence quantum efficiencies approaching unity in the blue wavelength range, where other metal-halide perovskites have typically been ineffective. However, the external quantum efficiencies (EQEs) of blue-emitting NPl light-emitting diodes (LEDs) have reached only 0.12%. In this work, we show that NPl LEDs are primarily limited by a poor electronic interface between the emitter and hole injector. We show that the NPls have remarkably deep ionization potentials (≥6.5 eV), leading to large barriers for hole injection, as well as substantial nonradiative decay at the NPl/hole-injector interface. We find that an effective way to reduce these nonradiative losses is by using poly(triarylamine) interlayers, which lead to an increase in the  EQE of the blue (464 nm emission wavelength) and sky-blue (489 nm emission wavelength) LEDs to 0.3% and 0.55%, respectively. Our work also identifies the key challenges for further efficiency increases

Optical orbital angular momentum: twisted light and chirality

The question of how the orbital angular momentum of structured light might engage with chiral matter is a topic of resurgent interest. By taking account of electric quadrupole transition moments, it is shown that the handedness of the beam can indeed be exhibited in local chiral effects, being dependent on the sign of the topological charge. In the specific case of absorption, a significant interplay of wavefront structure and polarization is resolved, and clear differences in behavior are identified for systems possessing a degree of orientational order and for those that are randomly oriented

Novel SSR Markers from BAC-End Sequences, DArT Arrays and a Comprehensive Genetic Map with 1,291 Marker Loci for Chickpea (Cicer arietinum L.)

Chickpea (Cicer arietinum L.) is the third most important cool season food legume, cultivated in arid and semi-arid regions of the world. The goal of this study was to develop novel molecular markers such as microsatellite or simple sequence repeat (SSR) markers from bacterial artificial chromosome (BAC)-end sequences (BESs) and diversity arrays technology (DArT) markers, and to construct a high-density genetic map based on recombinant inbred line (RIL) population ICC 4958 (C. arietinum)×PI 489777 (C. reticulatum). A BAC-library comprising 55,680 clones was constructed and 46,270 BESs were generated. Mining of these BESs provided 6,845 SSRs, and primer pairs were designed for 1,344 SSRs. In parallel, DArT arrays with ca. 15,000 clones were developed, and 5,397 clones were found polymorphic among 94 genotypes tested. Screening of newly developed BES-SSR markers and DArT arrays on the parental genotypes of the RIL mapping population showed polymorphism with 253 BES-SSR markers and 675 DArT markers. Segregation data obtained for these polymorphic markers and 494 markers data compiled from published reports or collaborators were used for constructing the genetic map. As a result, a comprehensive genetic map comprising 1,291 markers on eight linkage groups (LGs) spanning a total of 845.56 cM distance was developed (http://cmap.icrisat.ac.in/cmap/sm/cp/thudi/). The number of markers per linkage group ranged from 68 (LG 8) to 218 (LG 3) with an average inter-marker distance of 0.65 cM. While the developed resource of molecular markers will be useful for genetic diversity, genetic mapping and molecular breeding applications, the comprehensive genetic map with integrated BES-SSR markers will facilitate its anchoring to the physical map (under construction) to accelerate map-based cloning of genes in chickpea and comparative genome evolution studies in legumes