185 research outputs found
Enhancing the Stretchability of Two-Dimensional Materials through Kirigami: A Molecular Dynamics Study on Tungsten Disulfide
In recent years, the 'kirigami' technique has gained significant attention
for creating meta-structures and meta-materials with exceptional
characteristics, such as unprecedented stretchability. These properties, not
typically inherent in the original materials or structures, present new
opportunities for applications in stretchable electronics and photovoltaics.
However, despite its scientific and practical significance, the application of
kirigami patterning on a monolayer of tungsten disulfide (WS2), a van der Waals
material with exceptional mechanical, electronic, and optical properties, has
remained unexplored. This study utilizes molecular dynamics (MD) simulations to
investigate the mechanical properties of monolayer WS2 with rectangular
kirigami cuts. We find that, under tensile loading, the WS2 based kirigami
structure exhibits a notable increase in tensile strain and a decrease in
strength, thus demonstrating the effectiveness of the kirigami cutting
technique in enhancing the stretchability of monolayer WS2. Additionally,
increasing the overlap ratio enhances the stretchability of the structure,
allowing for tailored high strength or high strain requirements. Furthermore,
our observations reveal that increasing the density of cuts and reducing the
length-to-width ratio of the kirigami nanosheet further improve the fracture
strain, thereby enhancing the overall stretchability of the proposed kirigami
patterned structure of WS2.Comment: 19 pages, 5 figure
Long-term groundwater recharge rates across India by in situ measurements
Groundwater recharge sustains groundwater discharge, including natural
discharge through springs and the base flow to surface water as well as
anthropogenic discharge through pumping wells. Here, for the first time, we
compute long-term (1996–2015) groundwater recharge rates using data retrieved
from several groundwater-level monitoring locations across India (3.3Â million km2
area), the most groundwater-stressed region globally. Spatial
variations in groundwater recharge rates (basin-wide mean: 17 to
960 mm yr−1)
were estimated in the 22 major river basins across India. The extensive
plains of the Indus–Ganges–Brahmaputra (IGB) river basins are subjected to
prevalence of comparatively higher recharge. This is mainly attributed to
occurrence of coarse sediments, higher rainfall, and intensive
irrigation-linked groundwater-abstraction inducing recharge by increasing
available groundwater storage and return flows. Lower recharge rates
(<200 mm yr−1) in most of the central and southern study areas occur
in cratonic, crystalline fractured aquifers. Estimated recharge rates have
been compared favorably with field-scale recharge estimates (n=52) based
on tracer (tritium) injection tests. Results show that precipitation rates do
not significantly influence groundwater recharge in most of the river basins
across India, indicating human influence in prevailing recharge rates. The
spatial variability in recharge rates could provide critical input for policymakers to develop more sustainable groundwater management in India.</p
High spatial resolution imaging of methane and other trace gases with the airborne Hyperspectral Thermal Emission Spectrometer (HyTES)
Currently large uncertainties exist associated with the
attribution and quantification of fugitive emissions of criteria pollutants
and greenhouse gases such as methane across large regions and key economic
sectors. In this study, data from the airborne Hyperspectral Thermal
Emission Spectrometer (HyTES) have been used to develop robust and reliable
techniques for the detection and wide-area mapping of emission plumes of
methane and other atmospheric trace gas species over challenging and diverse
environmental conditions with high spatial resolution that permits direct
attribution to sources. HyTES is a pushbroom imaging spectrometer with high
spectral resolution (256 bands from 7.5 to 12 µm), wide swath (1–2 km),
and high spatial resolution (∼ 2 m at 1 km altitude) that
incorporates new thermal infrared (TIR) remote sensing technologies. In this
study we introduce a hybrid clutter matched filter (CMF) and plume dilation
algorithm applied to HyTES observations to efficiently detect and
characterize the spatial structures of individual plumes of CH4,
H2S, NH3, NO2, and SO2 emitters. The sensitivity and
field of regard of HyTES allows rapid and frequent airborne surveys of large
areas including facilities not readily accessible from the surface. The
HyTES CMF algorithm produces plume intensity images of methane and other
gases from strong emission sources. The combination of high spatial
resolution and multi-species imaging capability provides source attribution
in complex environments. The CMF-based detection of strong emission sources
over large areas is a fast and powerful tool needed to focus on more
computationally intensive retrieval algorithms to quantify emissions with
error estimates, and is useful for expediting mitigation efforts and
addressing critical science questions
High spatial resolution imaging of methane and other trace gases with the airborne Hyperspectral Thermal Emission Spectrometer (HyTES)
Currently large uncertainties exist associated with the attribution and quantification of fugitive emissions of criteria pollutants and greenhouse gases such as methane across large regions and key economic sectors. In this study, data from the airborne Hyperspectral Thermal Emission Spectrometer (HyTES) have been used to develop robust and reliable techniques for the detection and wide-area mapping of emission plumes of methane and other atmospheric trace gas species over challenging and diverse environmental conditions with high spatial resolution that permits direct attribution to sources. HyTES is a pushbroom imaging spectrometer with high spectral resolution (256 bands from 7.5 to 12 µm), wide swath (1–2 km), and high spatial resolution (∼ 2 m at 1 km altitude) that incorporates new thermal infrared (TIR) remote sensing technologies. In this study we introduce a hybrid clutter matched filter (CMF) and plume dilation algorithm applied to HyTES observations to efficiently detect and characterize the spatial structures of individual plumes of CH_4, H_2S, NH_3, NO_2, and SO_2 emitters. The sensitivity and field of regard of HyTES allows rapid and frequent airborne surveys of large areas including facilities not readily accessible from the surface. The HyTES CMF algorithm produces plume intensity images of methane and other gases from strong emission sources. The combination of high spatial resolution and multi-species imaging capability provides source attribution in complex environments. The CMF-based detection of strong emission sources over large areas is a fast and powerful tool needed to focus on more computationally intensive retrieval algorithms to quantify emissions with error estimates, and is useful for expediting mitigation efforts and addressing critical science questions
Performance of a North American Field Population and a Laboratory Colony of the Potato Tuberworm, Phthorimaea operculella, on Foliage of Resistant and Susceptible Potato Clones
Foliar resistance of two potato clones was tested against a Columbia Basin field population (CBFP) and a Colorado laboratory colony (COLC) of the potato tuberworm, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae). The first clone was a cross of a cultivated potato, Solanum tuberosum L. (Solanales: Solanaceae), and a wild potato, Solanum berthaultii Hawkes (Q 174-2); the second clone was cv. Allegany, S. tuberosum L.. In no-choice assays, defoliation by P. operculella larvae of COLC and CBFP did not differ on Allegany and Q174-2. Larval weight and production of COLC and CBFP colonies were similarly reduced on Q174-2 compared to cv. Allegany, although larval weights and production of the CBFP population were slightly less affected by the host. Larval production by the COLC on Allegany was greater than that on Q174-2, while that of the CBFP on Allegany and Q174-2 did not differ. However, production of P. operculella larvae by the CBFP on Q174-2 during no-choice assays was greater than that in choice tests, indicating reduced host preference. Most of the larvae recovered from either host were fourth instars, followed by third instars. Although the levels of resistance expressed by Q174-2 potato clone to the two P. operculella populations differed in magnitude, nearly all of P. operculella performance criteria measured in this study were adversely affected by Q174-2 foliage compared to the commercial potato cultivar, cv. Allegany
Hypoxia-induced long non-coding RNA Malat1 is dispensable for renal ischemia/reperfusion-injury
Renal ischemia-reperfusion (I/R) injury is a major cause of acute kidney injury (AKI). Non-coding RNAs are crucially involved in its pathophysiology. We identified hypoxia-induced long non-coding RNA Malat1 (Metastasis Associated Lung Adenocarcinoma Transcript 1) to be upregulated in renal I/R injury. We here elucidated the functional role of Malat1 in vitro and its potential contribution to kidney injury in vivo. Malat1 was upregulated in kidney biopsies and plasma of patients with AKI, in murine hypoxic kidney tissue as well as in cultured and ex vivo sorted hypoxic endothelial cells and tubular epithelial cells. Malat1 was transcriptionally activated by hypoxia-inducible factor 1-a. In vitro, Malat1 inhibition reduced proliferation and the number of endothelial cells in the S-phase of the cell cycle. In vivo, Malat1 knockout and wildtype mice showed similar degrees of outer medullary tubular epithelial injury, proliferation, capillary rarefaction, inflammation and fibrosis, survival and kidney function. Small-RNA sequencing and whole genome expression analysis revealed only minor changes between ischemic Malat1 knockout and wildtype mice. Contrary to previous studies, which suggested a prominent role of Malat1 in the induction of disease, we did not confirm an in vivo role of Malat1 concerning renal I/Rinjury
Influence of leaf trichome type, and density on the host plant selection by the greenhouse whitefly, Trialeurodes vaporariorum (Hemiptera: Aleyrodidae)
Host selection by adult greenhouse whitefly Trialeurodes vaporariorum (Westwood) was assessed on two pelargonium plant cultivars, Pelargonium x domesticum (regal) and P. x hortorum (zonal) using Petri dish bioassay chambers in choice and no-choice tests. Plant characteristics which could influence the oviposition preference of the whitely i.e., type and density of trichomes on the abaxial leaf surface was determined. A strong host preference was observed for the regal compared to the zonal pelargonium by the adult whiteflies. In no-choice tests, adults laid a significantly higher number of eggs on regal than on zonal leaves both at 24 and 48 hours post-exposure, respectively. After exposure to the adult whitefly, the number of
42 eggs in choice tests were similar between cultivars at 24 hours, but were higher for regal at 48 and 72 hours. The total number of trichomes (sng: straight non-glandular + sg: straight glandular) per 0.50 cm2 44 was significantly less on regal (Mean ± SE sng + sg; 43.1 ± 1.5) than on zonal leaves (60.5 ± 1.2); however, the sng trichomes were significantly higher on the zonal (49.4 ± 0.96) than the regal leaves (28.6 ± 1.00). Also, the number of sg trichomes was slightly higher for the regal cultivar leaves compared to the zonal, being 14.4 ± 1.2 and 11.2 ± 0.5, respectively. Results suggest that the trichome density, type and the ability to express glandular exudates can affect adult whitefly Pelargonium cultivar preference and plays an important role in their host plant selection for oviposition
Mechanistic Insight into the Reactivation of BCAII Enzyme from Denatured and Molten Globule States by Eukaryotic Ribosomes and Domain V rRNAs
In all life forms, decoding of messenger-RNA into polypeptide chain is accomplished by the ribosome. Several protein chaperones are known to bind at the exit of ribosomal tunnel to ensure proper folding of the nascent chain by inhibiting their premature folding in the
densely crowded environment of the cell. However, accumulating evidence suggests that ribosome may play a chaperone role in protein folding events in vitro. Ribosome-mediated folding of denatured proteins by prokaryotic ribosomes has been studied extensively. The
RNA-assisted chaperone activity of the prokaryotic ribosome has been attributed to the domain V, a span of 23S rRNA at the intersubunit side of the large subunit encompassing
the Peptidyl Transferase Centre. Evidently, this functional property of ribosome is unrelated to the nascent chain protein folding at the exit of the ribosomal tunnel. Here, we seek to scrutinize whether this unique function is conserved in a primitive kinetoplastid group of eukaryotic species Leishmania donovani where the ribosome structure possesses distinct additional features and appears markedly different compared to other higher eukaryotic
ribosomes. Bovine Carbonic Anhydrase II (BCAII) enzyme was considered as the model protein. Our results manifest that domain V of the large subunit rRNA of Leishmania ribosomes
preserves chaperone activity suggesting that ribosome-mediated protein folding is, indeed, a conserved phenomenon. Further, we aimed to investigate the mechanism underpinning the ribosome-assisted protein reactivation process. Interestingly, the surface plasmon resonance binding analyses exhibit that rRNA guides productive folding by directly interacting with molten globule-like states of the protein. In contrast, native protein shows no
notable affinity to the rRNA. Thus, our study not only confirms conserved, RNA-mediated chaperoning role of ribosome but also provides crucial insight into the mechanism of the process
Run and tumble particle under resetting:a renewal approach
We consider a particle undergoing run and tumble dynamics, in which its
velocity stochastically reverses, in one dimension. We study the addition of a
Poissonian resetting process occurring with rate . At a reset event the
particle's position is returned to the resetting site and the particle's
velocity is reversed with probability . The case corresponds
to position resetting and velocity randomization whereas corresponds
to position-only resetting. We show that, beginning from symmetric initial
conditions, the stationary state does not depend on i.e. it is
independent of the velocity resetting protocol. However, in the presence of an
absorbing boundary at the origin, the survival probability and mean time to
absorption do depend on the velocity resetting protocol. Using a renewal
equation approach, we show that the the mean time to absorption is always less
for velocity randomization than for position-only resetting.Comment: 16 pages, 1 figure, version accepted in Journal of Physics
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