3,842 research outputs found
Contribution of time of day and the circadian clock to the heat stress responsive transcriptome in Arabidopsis.
In Arabidopsis, a large subset of heat responsive genes exhibits diurnal or circadian oscillations. However, to what extent the dimension of time and/or the circadian clock contribute to heat stress responses remains largely unknown. To determine the direct contribution of time of day and/or the clock to differential heat stress responses, we probed wild-type and mutants of the circadian clock genes CCA1, LHY, PRR7, and PRR9 following exposure to heat (37 °C) and moderate cold (10 °C) in the early morning (ZT1) and afternoon (ZT6). Thousands of genes were differentially expressed in response to temperature, time of day, and/or the clock mutation. Approximately 30% more genes were differentially expressed in the afternoon compared to the morning, and heat stress significantly perturbed the transcriptome. Of the DEGs (~3000) specifically responsive to heat stress, ~70% showed time of day (ZT1 or ZT6) occurrence of the transcriptional response. For the DEGs (~1400) that are shared between ZT1 and ZT6, we observed changes to the magnitude of the transcriptional response. In addition, ~2% of all DEGs showed differential responses to temperature stress in the clock mutants. The findings in this study highlight a significant role for time of day in the heat stress responsive transcriptome, and the clock through CCA1 and LHY, appears to have a more profound role than PRR7 and PRR9 in modulating heat stress responses during the day. Our results emphasize the importance of considering the dimension of time in studies on abiotic stress responses in Arabidopsis
In-plane anisotropy on the transport properties in the modulated Bi_2O_2-based conductors Bi-2212 and Bi-Sr-Co-O
We investigated the in-plane anisotropy on the resistivity and thermopower of
the Bi_2Sr_2CaCu_2O_{8+\delta} (Bi-2212) and Bi-Sr-Co-O (BiCo) single crystals.
In Bi-2212, the b-axis resistivity is higher than the a-axis resistivity, and
is expressed as a sum of the a-axis resistivity and an additional residual
resistivity. A downward deviation due to pseudogap is observed below a
characteristic temperature T^*, which is isotropic in the form of conductivity.
These results suggest that the modulation structure along the b-axis works as
an anisotropic scattering center, but does not affect the pseudogap formation.
On the other hand, the anisotropy of the resistivity and the thermopower in
Pb-doped BiCo is substantial, probably owing to the misfit structure between
the hexagonal CoO_2 layer and the rock salt Bi_2O_2 layer. However, the
anisotropy in the resistivity in Pb-free BiCo is very small, suggesting that
the in-plane anisotropy is averaged by the modulation structure, whose
direction is tilted by 45 deg from the a- and b-axes.Comment: 4pages 5 figures, Proceedings of ISS2001, Physica C (in press
A preliminary checklist of fungi at the Boston Harbor Islands
Between December 2012 and May 2017, we conducted a fungal inventory at the Boston Harbor Islands National Recreation Area (BHI) in Massachusetts. We extensively sampled 4 sites (Grape Island, Peddocks Island, Thompson Island, and World's End peninsula) and occasionally visited 4 others for sampling (Calf Island, Great Brewster Island, Slate Island, and Webb Memorial State Park). We made over 900 collections, of which 313 have been identified. The survey yielded 172 species in 123 genera, 62 families, 24 orders, 11 classes, and 2 phyla. We report 4 species as new, but not formally described, in the genera Orbilia, Resupinatus, and Xylaria. Another collection in the genus Lactarius may be new to science, but further morphological and molecular work is needed to confirm this conclusion. Additionally, Orbilia aprilis is a new report for North America, Proliferodiscus earoleucus represents only the second report for the US, and Chrysosporium sulfureum, a common fungus of some cheeses, was discovered on woodlice (Crustacea: Malacostraca: Isopoda: Oniscidea). We discuss our findings in the light of DNA-based identifications using the ITS ribosomal DNA region, including the advantages and disadvantages of this approach, and stress the need for biodiversity studies in urbanized areas during all seasons
Scattering of a proton with the Li4 cluster: non-adiabatic molecular dynamics description based on time-dependent density-functional theory
We have employed non-adiabatic molecular dynamics based on time-dependent
density-functional theory to characterize the scattering behaviour of a proton
with the Li cluster. This technique assumes a classical approximation for
the nuclei, effectively coupled to the quantum electronic system. This
time-dependent theoretical framework accounts, by construction, for possible
charge transfer and ionization processes, as well as electronic excitations,
which may play a role in the non-adiabatic regime. We have varied the incidence
angles in order to analyze the possible reaction patterns. The initial proton
kinetic energy of 10 eV is sufficiently high to induce non-adiabatic effects.
For all the incidence angles considered the proton is scattered away, except in
one interesting case in which one of the Lithium atoms captures it, forming a
LiH molecule. This theoretical formalism proves to be a powerful, effective and
predictive tool for the analysis of non-adiabatic processes at the nanoscale.Comment: 18 pages, 4 figure
Cryogenic Refractive Indices of S-LAH55, S-LAH55V, S-LAH59, S-LAM3, S-NBM51, S-NPH2, S-PHM52, and S-TIH14 Glasses
The Transiting Exoplanet Survey Satellite (TESS) is an explorer-class planet finder, whose principal goal is to detect small planets with bright host starts in the solar neighborhood. The TESS payload consists of four identical cameras with seven optical elements each that include various types of Ohara glass substrates. The successful implementation both panchromatic and thermal lens assembly designs for these cameras requires a fairly accurate (up to 1E-6) knowledge of the temperature and wavelength dependence of the refractive index in the wavelength and temperature range of operation. Hence, this paper is devoted to report on measurements of the refractive index over the wavelength range of 0.42-1.15 um and temperature range of 110-310 K for the following Ohara glasses: S-LAH55, S-LAH55V, SLAH59, S-LAM3, S-NBM51, S-NPH2, S-PHM52, and S-TIH14. The measurements were performed utilizing the Cryogenic High Accuracy Refraction Measuring System (CHARMS) facility at NASA's Goddard Space Flight Center. A dense coverage of the absolute refractive index for the title substrates in the aforementioned wavelength and temperature ranges was used to determine the thermo-optic coefficient (dn/dT) and dispersion relation (dn/d lambda) as a function of wavelength and temperature. A comparison of the measured indices with literature values, specifically the temperature-dependent refractive indices of S-PHM52 and S-TIH14, will be presented
Electrocatalytic Oxidation of Cyanide on Copper-doped Cobalt Oxide Electrodes
[EN] Copper and copper oxides are well-known excellent catalysts in several chemical processes, but their low mechanical and electrochemical stability restrict their direct utilization as electrodes in electrolytic processes. In this work, the incorporation of copper into cobalt oxide (CuxCo3-xO4) is presented as an excellent approach to obtain highly active and robust copper-based electrocatalysts. Particularly, the electrocatalytic performance of Ti-supported CuxCo3-xO4 electrodes (with 0 <= x <= 1.5) has been studied for the oxidation' of cyanide in alkaline media. Cyclic voltammetry and electrolysis runs show an outstanding effect of Cu on the activity, efficiency and kinetics of spinel CuxCo3-xO4 electrodes for CN(-)electro-oxidation. Despite being active oxides with high activity towards water oxidation, copper saturated (x=1.0) and oversaturated (x=1.5) spinels exhibit unprecedented 100% current efficiencies for the electro-oxidation of CN- in aqueous electrolyte. In situ surface enhanced Raman spectroscopy (SERS) reveals the specific adsorption of CN- ions on surface Cu species to be involved in the electrocatalytic oxidation mechanism. This electrocatalytic activity has been attributed to surface Cu(II) in the spinel lattice. Furthermore, the CuxCo3-xO4 electrodes also display high electrochemical stability. Therefore, they are considered excellent candidates for the sustainable electrochemical elimination of highly toxic cyanides.Financial support from the Spanish Ministerio de Economia y Competitividad and FEDER funds (MAT2016-76595-R, IJCI-2014-20012) and from the Generalitat Valenciana (PROMETEO2013/038) is gratefully acknowledged.Berenguer, R.; La Rosa-Toro, A.; Quijada, C.; Morallon, E. (2017). Electrocatalytic Oxidation of Cyanide on Copper-doped Cobalt Oxide Electrodes. Applied Catalysis B Environmental. 207:286-296. https://doi.org/10.1016/j.apcatb.2017.01.078S28629620
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