Viet Nam has a coastline of 3200 km with thousands of islands providing diverse habitats for benthic harmful algal species including species of Gambierdiscus. Some of these species produce ciguatera ...toxins, which may accumulate in large carnivore fish potentially posing major threats to public health. This study reports five species of Gambierdiscus from Vietnamese waters, notably G. australes, G. caribaeus, G. carpenteri, G. pacificus, and G. vietnamensis sp. nov. All species are identified morphologically by LM and SEM, and identifications are supported by molecular analyses of nuclear rDNA (D1–D3 and D8–D10 domains of LSU, SSU, and ITS1‐5.8S‐ITS2 region) based on cultured material collected during 2010–2021. Statistical analyses of morphometric measurements may be used to differentiate some species if a sufficiently large number of cells are examined. Gambierdiscus vietnamensis sp. nov. is morphologically similar to other strongly reticulated species, such as G. belizeanus and possibly G. pacificus; the latter species is morphologically indistinguishable from G. vietnamensis sp. nov., but they are genetically distinct, and molecular analysis is deemed necessary for proper identification of the new species. This study also revealed that strains denoted G. pacificus from Hainan Island (China) should be included in G. vietnamensis sp. nov.
This study evaluated the antibacterial activity of electrochemically synthesized colloidal silver nanoparticles (AgNPs) against hospital-acquired infections. Colloidal AgNPs were synthesized via a ...single process using bulk silver bars, bi-distilled water, trisodium citrate, and direct current voltage at room temperature. Colloidal AgNPs were characterized by transmission electron microscopy, field-emission scanning electron microscopy, and energy-dispersive x-ray analyses. The antibacterial activity of colloidal AgNPs against four bacterial strains isolated from clinical samples, including methicillin-resistant
Staphylococcus aureus
,
Escherichia coli
O157:H7, multidrug-resistant
Pseudomonas aeruginosa
, and carbapenem-resistant
Klebsiella pneumonia
, was evaluated by disc diffusion, minimum inhibitory concentration (MIC), and ultrathin sectioning electron microscopy. The results showed that the prepared AgNPs were 19.7 ± 4.3 nm in size, quasi-spherical, and of high purity. Zones of inhibition approximately 6–10 mm in diameter were found, corresponding to AgNPs concentrations of 50 μg/mL to 100 μg/mL. The MIC results revealed that the antibacterial activity of the prepared AgNPs was strongly dependent on the concentration and strain of the tested bacteria.
A major obstacle in prioritizing species or habitats for conservation is the degree of unrecognized diversity hidden within complexes of morphologically similar, "cryptic" species. Given that ...amphibians are one of the most threatened groups of organisms on the planet, our inability to diagnose their true diversity is likely to have significant conservation consequences. This is particularly true in areas undergoing rapid deforestation, such as Southeast Asia. The Southeast Asian genus Leptolalax is a group of small-bodied, morphologically conserved frogs that inhabit the forest-floor. We examined a particularly small-bodied and morphologically conserved subset, the Leptolalax applebyi group, using a combination of molecular, morphometric, and acoustic data to identify previously unknown diversity within. In order to predict the geographic distribution of the group, estimate the effects of habitat loss and assess the degree of habitat protection, we used our locality data to perform ecological niche modelling using MaxEnt. Molecular (mtDNA and nuDNA), acoustic and subtle morphometric differences revealed a significant underestimation of diversity in the L. applebyi group; at least two-thirds of the diversity may be unrecognised. Patterns of diversification and microendemism in the group appear driven by limited dispersal, likely due to their small body size, with several lineages restricted to watershed basins. The L. applebyi group is predicted to have historically occurred over a large area of the Central Highlands of Vietnam, a considerable portion of which has already been deforested. Less than a quarter of the remaining forest predicted to be suitable for the group falls within current protected areas. The predicted distribution of the L. applebyi group extends into unsurveyed watershed basins, each potentially containing unsampled diversity, some of which may have already been lost due to deforestation. Current estimates of amphibian diversity based on morphology alone are misleading, and accurate alpha taxonomy is essential to accurately prioritize conservation efforts.
O-doped g-C3N4 (denoted as x-OCN, where x is the volume of 30% H2O2 for a given amount of urea) materials were prepared by calcining dried the mixtures of urea impregnated with H2O2 at 550 °C. The ...characterization shows that the x-OCN materials are formed by replacing N in g-C3N4 by O atoms, which is further supported by density functional theory calculations. The rhodamine B photodegradation performance on the x-OCN materials is higher than the pure g-C3N4. Among the x-OCN samples, 40-OCN shows the strongest photocatalytic activity, which could be attributed to the largest content of doped-O in the matrix of g-C3N4, leading to a reduced bandgap energy and a lower recombination rate of photogenerated electrons and holes, therefore enhancing the photocatalytic performance. The mechanism for the photocatalytic degradation of RhB was proposed based on the investigation on the role of active species and the pathway of RhB degradation.
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•O-doped g-C3N4 materials were prepared.•The photocatalytic performance for the materials was investigated.•The doping O in g-C3N4 lead to an improvement in its photocatalytic performance.
Summary
In this work, we present the results obtained from integrating several machine learning (ML) models with projection‐based reduced order model for modeling the canonical case of flow past a ...stationary cylinder. We demonstrate how ML models can be used to model the time‐varying characteristics of the proper orthogonal decomposition (POD) coefficients, and that the locally interpolating models such as regression trees and k‐nearest neighbors seem to be better for such models than other models like support vector regression or long‐short term memory networks. In addition, our numerical experiments also show that these POD coefficients are most effectively modeled by using their own previous time values, as opposed to the inclusion of high energy POD modes. Last but not least, we demonstrate that these models, although trained on inlet velocities of 0.8, 1.0, and 1.2 m/s, can still predict the POD coefficients of flow fields for inlet velocities of 0.9 and 1.25 m/s, with root mean squared error of under 10%.
In this work, we integrate several machine learning models with projection‐based reduced order model for modeling the flow past a stationary cylinder and evaluate the choice of modeling parameters and training times required to better guide future design of such hybrid models. We demonstrate how locally‐interpolating models such as regression trees and k‐nearest neighbors perform better than support vector regression or neural networks and that these models can successfully predict the POD coefficients for various inlet velocities.
Abstract
LARP1 is a key repressor of TOP mRNA translation. It binds the m7Gppp cap moiety and the adjacent 5′TOP motif of TOP mRNAs, thus impeding the assembly of the eIF4F complex on these ...transcripts. mTORC1 controls TOP mRNA translation via LARP1, but the details of the mechanism are unclear. Herein we elucidate the mechanism by which mTORC1 controls LARP1’s translation repression activity. We demonstrate that mTORC1 phosphorylates LARP1 in vitro and in vivo, activities that are efficiently inhibited by rapamycin and torin1. We uncover 26 rapamycin-sensitive phospho-serine and -threonine residues on LARP1 that are distributed in 7 clusters. Our data show that phosphorylation of a cluster of residues located proximally to the m7Gppp cap-binding DM15 region is particularly sensitive to rapamycin and regulates both the RNA-binding and the translation inhibitory activities of LARP1. Our results unravel a new model of translation control in which the La module (LaMod) and DM15 region of LARP1, both of which can directly interact with TOP mRNA, are differentially regulated: the LaMod remains constitutively bound to PABP (irrespective of the activation status of mTORC1), while the C-terminal DM15 ‘pendular hook’ engages the TOP mRNA 5′-end to repress translation, but only in conditions of mTORC1 inhibition.
The Leptolalax applebyi group of Asian leaf-litter frogs currently comprises four species of particularly small-bodied (<40 mm SVL) species distributed in the Central Highlands of Vietnam and ...northeastern Cambodia. In addition to their small size, the group is characterized by their morphological and genetic similarities, as well as their breeding habitat at headwaters of small mountain streams and seeps. A recent study suggested that at least two-thirds of the diversity of the group remained hidden within morphologically cryptic lineages. We expand upon the molecular, morphometric, and acoustic data and formally delineate and describe five of these lineages as distinct species: Leptolalax ardens sp. nov., Leptolalax kalonensis sp. nov., Leptolalax pallidus sp. nov., Leptolalax maculosus sp. nov., and Leptolalax tadungensis sp. nov. Due to habitat loss, the current ranges of these species are likely to be a fraction of their historical extent and under continued threat from deforestation.
•Explicit projection of the pressure Poisson equation and the predictor-corrector scheme for solving the pressure equation.•Dirichlet and Neumann boundary conditions are considered for general fluid ...dynamics problems.•OpenFoam platform used to build the ROMs for problems with complex geometries and boundary conditions.•Neural network (Nonlinear autoregressive eXogenous model) approach is explored for mapping among variables.•ROMs are tested for true predictions, i.e. modelling new cases that have not seen in the model construction.
This paper presents complete steps for the construction and solution algorithm for a projection-based reduced order model coupled with an artificial neural net model. The reduced model is constructed based on the Galerkin projection of the equations governing the physical processes on reduced subspaces obtained by the Proper Orthogonal Decomposition method. The projection is done using numerical discretisation schemes implemented in the commonly used OpenFOAMⓇ platform. The neural net model is trained using the Nonlinear AutoRegressive eXogenous model network (NARX) architecture. The reduced order models are demonstrated for true predictions of incompressible flows at low Reynolds numbers driven by various boundary conditions. Compared with the full CFD simulations, this model shows excellent agreement while only requiring a fraction of the computational resources.
In recent years, extracellular vesicles (EVs) secreted by mesenchymal stem cells (MSCs) have emerged as a potential cell-free therapy against osteoarthritis (OA). Thus, we investigated the ...therapeutic effects of EVs released by cytokine-primed umbilical cord-derived MSCs (UCMSCs) on osteoarthritic chondrocyte physiology. Priming UCMSCs individually with transforming growth factor beta (TGFβ), interferon alpha (IFNα), or tumor necrosis factor alpha (TNFα) significantly reduced the sorting of miR-181b-3p but not miR-320a-3p; two negative regulators of chondrocyte regeneration, into EVs. However, the EV treatment did not show any significant effect on chondrocyte proliferation. Meanwhile, EVs from both non-priming and cytokine-primed UCMSCs induced migration at later time points of measurement. Moreover, TGFβ-primed UCMSCs secreted EVs that could upregulate the expression of chondrogenesis markers (
COL2
and
ACAN
) and downregulate fibrotic markers (
COL1
and
RUNX2
) in chondrocytes. Hence, priming UCMSCs with cytokines can deliver selective therapeutic effects of EV treatment in OA and chondrocyte-related disorders.
The pharmaceutical industry has highlighted particle-size reduction via preparing aqueous suspensions containing nano- or submicron drug particles. Owing to the risk of agglomeration and ...complications during the manufacturing of solid dosage forms, the problems associated with the solidification of nanosuspensions need to be addressed. Herein, the nanocrystallized suspension of fenofibrate (Feno) was prepared using the wet-milling technique, and then two solidification methods, mixing (liquid mixing) and granulation (dry powder blending and wet massing) methods, were investigated. The solidification process involved the adsorption of Feno as a very thin layer on the high-surface-area Florite® to prevent drug accumulation. The critical quality attributes, particle size and dissolution rate, were performed. Infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, and scanning electron microscopy were also used to monitor the existence and physical state of drug molecules in the carrier. The final solidified powders and tablets containing Feno nanocrystals improved the dissolution profile (>90% in 15 min), in which the physical properties of Feno were maintained during solidification and tableting. In general, the granulation method is more advantageous than the mixing method in terms of maintaining amorphous proportion and dissolution rate. These results implied a potential approach for manufacturing solid dosage forms from nanoscale products.
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