57 research outputs found
Atmospheric correction using 1240 and 2130 nm combination of MODIS SWIR channels
It is essential to improve understanding of coastal ocean since the majority of the world's primary production occurs on continental shelves and the coastal ocean is most utilized and impacted by humans. The first step in ocean-colour data processing is the removal of atmospheric contribution from the sensor-detected radiance to enable detection of optically active oceanic constituents e.g. chlorophyll-a, suspended sediment etc. Black ocean assumption at the near infrared (NIR) wavelengths as applied to perform atmospheric correction fails for coastal turbid waters due to the presence of highly scattering sediments which cause sufficient water-leaving radiance in NIR wavelengths and lead to over-estimation of aerosol radiance for λ <700nm resulting in negative water leaving radiance for λ <500nm. The assumption of zero water-leaving radiance at the NIR wavelengths was replaced by the assumption of zero water-leaving radiance at the short wave infrared (SWIR) wavelengths over the coastal turbid waters and atmospheric correction was performed using these SWIR wavelengths. Physically realistic and positive water leaving radiances
throughout the spectrum and especially for shorter wavelengths (412nm, 443nm, 490nm) were obtained over coastal turbid waters using this concept
Vesiclepedia 2019 :Â a compendium of RNA, proteins, lipids and metabolites in extracellular vesicles
Extracellular vesicles (EVs) are membranous vesicles that are released by both prokaryotic and eukaryotic cells into the extracellular microenvironment. EVs can be categorised as exosomes, ectosomes or shedding microvesicles and apoptotic bodies based on the mode of biogenesis. EVs contain biologically active cargo of nucleic acids, proteins, lipids and metabolites that can be altered based on the precise state of the cell. Vesiclepedia (http://www.microvesicles.org) is a web-based compendium of RNA, proteins, lipids and metabolites that are identified in EVs from both published and unpublished studies. Currently, Vesiclepedia contains data obtained from 1254 EV studies, 38 146 RNA entries, 349 988 protein entries and 639 lipid/metabolite entries. Vesiclepedia is publicly available and allows users to query and download EV cargo based on different search criteria. The mode of EV isolation and characterization, the biophysical and molecular properties and EV-METRIC are listed in the database aiding biomedical scientists in assessing the quality of the EV preparation and the corresponding data obtained. In addition, FunRich-based Vesiclepedia plugin is incorporated aiding users in data analysis
Rising dissolved organic carbon concentrations in coastal waters of northwestern Borneo related to tropical peatland conversion
Southeast Asiaâs peatlands are considered a globally important source of terrigenous dissolved organic carbon (DOC) to the ocean. Human disturbance has probably increased peatland DOC fluxes, but the lack of monitoring has precluded a robust demonstration of such a regional-scale impact. Here, we use a time series of satellite ocean color data from northwestern Borneo to show that DOC concentrations in coastal waters have increased between 2002 and 2021 by 0.31 ÎŒmol literâ1 yearâ1 (95% confidence interval, 0.18 to 0.44 ÎŒmol literâ1 yearâ1). We show that this was caused by a â„30% increase in the concentration of terrigenous DOC and coincided with the conversion of 69% of regional peatland area to nonforest land cover, suggesting that peatland conversion has substantially increased DOC fluxes to the sea. This rise in DOC concentration has also increased the underwater light absorption by dissolved organic matter, which may affect marine productivity by altering underwater light availability
Distribution and cycling of terrigenous dissolved organic carbon in peatland-draining rivers and coastal waters of Sarawak, Borneo
South-East Asia is home to one of the worldâs
largest stores of tropical peatland and accounts for roughly 10 % of the global land-to-sea dissolved organic carbon (DOC) flux. We present the first ever seasonally resolved measurements of DOC concentration and chromophoric dissolved organic matter (CDOM) spectra for six peatlanddraining rivers and coastal waters in Sarawak, north-western Borneo. The rivers differed substantially in DOC concentration, ranging from 120â250 ”mol Lâ1 (Rajang River) to 3100â4400 ”mol Lâ1
(Maludam River). All rivers carried high CDOM concentrations, with a350 in the four blackwater
rivers between 70 and 210 mâ1 and 4 and 12 mâ1
in the other two rivers. DOC and CDOM showed conservative mixing with seawater except in the largest river (the Rajang), where DOC concentrations in the estuary were elevated, most likely due to inputs from the extensive peatlands within the Rajang Delta. Seasonal variation was moderate and inconsistent between rivers. However, during the rainier north-east monsoon, all marine stations in the western part of our study area had higher DOC concentrations and lower CDOM spectral slopes, indicating a greater proportion of terrigenous DOM in coastal waters. Photodegradation experiments revealed that
riverine DOC and CDOM in Sarawak are photolabile: up to
25 % of riverine DOC was lost within 5 days of exposure
to natural sunlight, and the spectral slopes of photo-bleached CDOM resembled those of our marine samples. We conclude that coastal waters of Sarawak receive large inputs of terrigenous DOC that is only minimally altered during estuarine transport and that any biogeochemical processing must therefore occur mostly at sea. It is likely that photodegradation plays an important role in the degradation of terrigenous DOC in these waters
Distribution and cycling of terrigenous dissolved organic carbon in peatland-draining rivers and coastal waters of Sarawak, Borneo
South-East Asia is home to one of the world's largest stores of tropical
peatland and accounts for roughly 10 % of the global land-to-sea dissolved
organic carbon (DOC) flux. We present the first ever seasonally resolved
measurements of DOC concentration and chromophoric dissolved organic matter
(CDOM) spectra for six peatland-draining rivers and coastal waters in
Sarawak, north-western Borneo. The rivers differed substantially in DOC
concentration, ranging from 120â250 ”mol Lâ1 (Rajang River) to
3100â4400 ”mol Lâ1 (Maludam River). All rivers carried high
CDOM concentrations, with a350 in the four blackwater rivers between
70 and 210 mâ1 and 4 and 12 mâ1 in the other two rivers. DOC and CDOM
showed conservative mixing with seawater except in the largest river (the
Rajang), where DOC concentrations in the estuary were elevated, most likely
due to inputs from the extensive peatlands within the Rajang Delta. Seasonal
variation was moderate and inconsistent between rivers. However, during the
rainier north-east monsoon, all marine stations in the western part of our
study area had higher DOC concentrations and lower CDOM spectral slopes,
indicating a greater proportion of terrigenous DOM in coastal waters.
Photodegradation experiments revealed that riverine DOC and CDOM in Sarawak
are photolabile: up to 25 % of riverine DOC was lost within 5 days of
exposure to natural sunlight, and the spectral slopes of photo-bleached CDOM
resembled those of our marine samples. We conclude that coastal waters of
Sarawak receive large inputs of terrigenous DOC that is only minimally
altered during estuarine transport and that any biogeochemical processing
must therefore occur mostly at sea. It is likely that photodegradation plays
an important role in the degradation of terrigenous DOC in these
waters.</p
Super-transport of Excitons in Atomically Thin Organic Semiconductors at the 2D Quantum Limit
Long-range and fast transport of coherent excitons is important for
development of high-speed excitonic circuits and quantum computing
applications. However, most of these coherent excitons have only been observed
in some low-dimensional semiconductors when coupled with cavities, as there are
large inhomogeneous broadening and dephasing effects on the exciton transport
in their native states of the materials. Here, by confining coherent excitons
at the 2D quantum limit, we firstly observed molecular aggregation enabled
super-transport of excitons in atomically thin two-dimensional (2D) organic
semiconductors between coherent states, with a measured a high effective
exciton diffusion coefficient of 346.9 cm2/sec at room temperature. This value
is one to several orders of magnitude higher than the reported values from
other organic molecular aggregates and low-dimensional inorganic materials.
Without coupling to any optical cavities, the monolayer pentacene sample, a
very clean 2D quantum system (1.2 nm thick) with high crystallinity (J type
aggregation) and minimal interfacial states, showed superradiant emissions from
the Frenkel excitons, which was experimentally confirmed by the
temperature-dependent photoluminescence (PL) emission, highly enhanced
radiative decay rate, significantly narrowed PL peak width and strongly
directional in-plane emission. The coherence in monolayer pentacene samples was
observed to be delocalized over 135 molecules, which is significantly larger
than the values (a few molecules) observed from other organic thin films. In
addition, the super-transport of excitons in monolayer pentacene samples showed
highly anisotropic behaviour. Our results pave the way for the development of
future high-speed excitonic circuits, fast OLEDs, and other opto-electronic
devices
A New Remote Sensing Method to Estimate River to Ocean DOC Flux in Peatland Dominated Sarawak Coastal Regions, Borneo
We present a new remote sensing based method to estimate dissolved organic carbon (DOC) flux discharged from rivers into coastal waters off the Sarawak region in Borneo. This method comprises three steps. In the first step, we developed an algorithm for estimating DOC concentrations using the ratio of Landsat-8 Red to Green bands B4/B3 (DOC (ÎŒM C) = 89.86 â
e0.27â
(B4/B3)), which showed good correlation (R = 0.88) and low mean relative error (+5.71%) between measured and predicted DOC. In the second step, we used TRMM Multisatellite Precipitation Analysis (TMPA) precipitation data to estimate river discharge for the river basins. In the final step, DOC flux for each river catchment was then estimated by combining Landsat-8 derived DOC concentrations and TMPA derived river discharge. The analysis of remote sensing derived DOC flux (April 2013 to December 2018) shows that Sarawak coastal waters off the Rajang river basin, received the highest DOC flux (72% of total) with an average of 168 Gg C per year in our study area, has seasonal variability. The whole of Sarawak represents about 0.1% of the global annual riverine and estuarine DOC flux. The results presented in this study demonstrate the ability to estimate DOC flux using satellite remotely sensed observations
Oral administration of bovine milk-derived extracellular vesicles induces senescence in the primary tumor but accelerates cancer metastasis
The concept that extracellular vesicles (EVs) from the diet can be absorbed by the intestinal tract of the consuming organism, be bioavailable in various organs, and in-turn exert phenotypic changes is highly debatable. Here, we isolate EVs from both raw and commercial bovine milk and characterize them by electron microscopy, nanoparticle tracking analysis, western blotting, quantitative proteomics and small RNA sequencing analysis. Orally administered bovine milk-derived EVs survive the harsh degrading conditions of the gut, in mice, and is subsequently detected in multiple organs. Milk-derived EVs orally administered to mice implanted with colorectal and breast cancer cells reduce the primary tumor burden. Intriguingly, despite the reduction in primary tumor growth, milk-derived EVs accelerate metastasis in breast and pancreatic cancer mouse models. Proteomic and biochemical analysis reveal the induction of senescence and epithelial-to-mesenchymal transition in cancer cells upon treatment with milk-derived EVs. Timing of EV administration is critical as oral administration after resection of the primary tumor reverses the pro-metastatic effects of milk-derived EVs in breast cancer models. Taken together, our study provides context-based and opposing roles of milk-derived EVs as metastasis inducers and suppressors
Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches
© 2024 The Authors. Journal of Extracellular Vesicles, published by Wiley Periodicals, LLC on behalf of the International Society for Extracellular Vesicles. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly.Peer reviewe
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