493 research outputs found
Photo-excitation of a light-harvesting supra-molecular triad: a Time-Dependent DFT study
We present the first time-dependent density-functional theory (TDDFT)
calculation on a light harvesting triad carotenoid-diaryl-porphyrin-C60.
Besides the numerical challenge that the ab initio study of the electronic
structure of such a large system presents, we show that TDDFT is able to
provide an accurate description of the excited state properties of the system.
In particular we calculate the photo-absorption spectrum of the supra-molecular
assembly, and we provide an interpretation of the photo-excitation mechanism in
terms of the properties of the component moieties. The spectrum is in good
agreement with experimental data, and provides useful insight on the
photo-induced charge transfer mechanism which characterizes the system.Comment: Accepted for publication on JPC, March 09th 200
Draft genome of the lowland anoa (Bubalus depressicornis) and comparison with buffalo genome assemblies (Bovidae, Bubalina)
Genomic data for wild species of the genus Bubalus (Asian buffaloes) are still lacking while several whole genomes are currently available for domestic water buffaloes. To address this, we sequenced the genome of a wild endangered dwarf buffalo, the lowland anoa (Bubalus depressicornis), produced a draft genome assembly, and made comparison to published buffalo genomes. The lowland anoa genome assembly was 2.56 Gbp long and contained 103,135 contigs, the longest contig being 337.39 kbp long. N50 and L50 values were 38.73 kbp and 19.83 kbp, respectively, mean coverage was 44x and GC content was 41.74%. Two strategies were adopted to evaluate genome completeness: (i) determination of genomic features with de novo and homology-based predictions using annotations of chromosome-level genome assembly of the river buffalo, and (ii) employment of benchmarking against universal single-copy orthologs (BUSCO). Homology-based predictions identified 94.51% complete and 3.65% partial genomic features. De novo gene predictions identified 32,393 genes, representing 97.14% of the reference's annotated genes, whilst BUSCO search against the mammalian orthologues database identified 71.1% complete, 11.7% fragmented and 17.2% missing orthologues, indicating a good level of completeness for downstream analyses. Repeat analyses indicated that the lowland anoa genome contains 42.12% of repetitive regions. The genome assembly of the lowland anoa is expected to contribute to comparative genome analyses among bovid species. [Abstract copyright: © The Author(s) 2022. Published by Oxford University Press on behalf of Genetics Society of America.
Recommended from our members
New record of Sphagnum falcatulum Besch (Sphagnaceae) on Navarino Island, Cape Horn Biosphere Reserve
This article characterizes habitats of Navarino Island to quantify the coverage of three main types of terrestrial environments
Electron-Electron Interactions in Artificial Graphene
Recent advances in the creation and modulation of graphene-like systems are
introducing a science of "designer Dirac materials". In its original
definition, artificial graphene is a man-made nanostructure that consists of
identical potential wells (quantum dots) arranged in a adjustable honeycomb
lattice in the two-dimensional electron gas. As our ability to control the
quality of artificial graphene samples improves, so grows the need for an
accurate theory of its electronic properties, including the effects of
electron-electron interactions. Here we determine those effects on the band
structure and on the emergence of Dirac points
Changing lenses to assess biodiversity: patterns of species richness in sub-Antarctic plants and implications for global conservation
Embedded, micro-interdigitated flow fields in high areal-loading intercalation electrodes towards seawater desalination and beyond
Faradaic deionization (FDI) is a promising technology for energy-efficient
water desalination using porous electrodes containing redox-active materials.
Herein, we demonstrate for the first time the capability of a symmetric FDI
flow cell to produce freshwater (<17.1 mM NaCl) from concentrated brackish
water (118mM), to produce effluent near freshwater salinity (19.1 mM) from
influent with seawater-level salinity (496 mM), and to reduce the salinity of
hypersaline brine from 781 mM to 227 mM. These remarkable salt-removal levels
were enabled by using flow-through electrodes with high areal-loading of nickel
hexacyanoferrate (NiHCF) Prussian Blue analogue intercalation material. The
pumping energy consumption due to flow-through electrodes was mitigated by
embedding an interdigitated array of <100 m wide channels in the
electrodes using laser micromachining. The micron-scale dimensions of the
resulting embedded, micro-interdigitated flow fields (e-IDFFs) facilitate
flow-through electrodes with high apparent permeability while minimizing
active-material loss. Our modeling shows that these e-IDFFs are more
suitable for our intercalation electrodes because they have >100X lower
permeability compared to common redox-flow battery electrodes, for which
millimetric flow-channel widths were used exclusively in the past. Total
desalination thermodynamic energy efficiency (TEE) was improved by more than
ten-fold relative to unpatterned electrodes: 40.0% TEE for brackish water,
11.7% TEE for hypersaline brine, and 7.4% TEE for seawater-salinity feeds.
Water transport between diluate and brine streams and charge efficiency losses
resulting from (electro)chemical effects are implicated as limiting energy
efficiency and water recovery, motivating their investigation for enhancing
future FDI performance.Comment: 70 pages, 23 figures. Energy Environ. Sci. (2023
Terahertz plasmons in coupled two-dimensional semiconductor resonators
Advances in theory are needed to match recent progress in measurements of coupled semiconductor resonators supporting terahertz plasmons. Here, we present a field-based model of plasmonic resonators that comprise gated and ungated two-dimensional electron systems. The model is compared to experimental measurements of a representative system, in which the interaction between the gated and ungated modes leads to a rich spectrum of hybridized resonances. A theoretical framework is thus established for the analysis and design of gated low-dimensional systems used as plasmonic resonators, underlining their potential application in the manipulation of terahertz frequency range signals
Modal Analysis and Coupling in Metal-Insulator-Metal Waveguides
This paper shows how to analyze plasmonic metal-insulator-metal waveguides
using the full modal structure of these guides. The analysis applies to all
frequencies, particularly including the near infrared and visible spectrum, and
to a wide range of sizes, including nanometallic structures. We use the
approach here specifically to analyze waveguide junctions. We show that the
full modal structure of the metal-insulator-metal (MIM) waveguides--which
consists of real and complex discrete eigenvalue spectra, as well as the
continuous spectrum--forms a complete basis set. We provide the derivation of
these modes using the techniques developed for Sturm-Liouville and generalized
eigenvalue equations. We demonstrate the need to include all parts of the
spectrum to have a complete set of basis vectors to describe scattering within
MIM waveguides with the mode-matching technique. We numerically compare the
mode-matching formulation with finite-difference frequency-domain analysis and
find very good agreement between the two for modal scattering at symmetric MIM
waveguide junctions. We touch upon the similarities between the underlying
mathematical structure of the MIM waveguide and the PT symmetric quantum
mechanical pseudo-Hermitian Hamiltonians. The rich set of modes that the MIM
waveguide supports forms a canonical example against which other more
complicated geometries can be compared. Our work here encompasses the microwave
results, but extends also to waveguides with real metals even at infrared and
optical frequencies.Comment: 17 pages, 13 figures, 2 tables, references expanded, typos fixed,
figures slightly modifie
- …