Highly compressible three-dimensional graphene aerogels with anisotropic porous structure are fabricated by directional freezing of graphene hydrogel using anisotropically grown ice crystals as ...templates followed by freeze–drying. The directional freezing approach endows the graphene aerogel with a high compressive strength in the axial direction and good compressibility in both axial and radial directions. The anisotropic graphene aerogel also exhibits ultralow density, excellent flexibility in liquids, satisfactory fire-resistance, and strain-sensitive electrical conductivity. After absorbing organic liquids, the aerogel can be well recycled by burning, distilling, or squeezing, which makes it promising for oil absorption with a good recyclability.
•Highly compressible graphene aerogels with anisotropic porous structure are fabricated by directional-freezing.•The directional-freezing approach endows the aerogel with an excellent compressibility in both axial and radial directions.•The anisotropic aerogel is promising for oil absorption with good recyclability by combustion, distilling and squeezing.•The aerogel exhibits ultralow density, excellent flexibility in liquid and a strain-sensitive electrical conductivity.
Temperature stress is one of the major abiotic stresses that adversely affect agricultural productivity worldwide. Temperatures beyond a plant’s physiological optimum can trigger significant ...physiological and biochemical perturbations, reducing plant growth and tolerance to stress. Improving a plant’s tolerance to these temperature fluctuations requires a deep understanding of its responses to environmental change. To adapt to temperature fluctuations, plants tailor their acclimatory signal transduction events, and specifically, cellular redox state, that are governed by plant hormones, reactive oxygen species (ROS) regulatory systems, and other molecular components. The role of ROS in plants as important signaling molecules during stress acclimation has recently been established. Here, hormone-triggered ROS produced by NADPH oxidases, feedback regulation, and integrated signaling events during temperature stress activate stress-response pathways and induce acclimation or defense mechanisms. At the other extreme, excess ROS accumulation, following temperature-induced oxidative stress, can have negative consequences on plant growth and stress acclimation. The excessive ROS is regulated by the ROS scavenging system, which subsequently promotes plant tolerance. All these signaling events, including crosstalk between hormones and ROS, modify the plant’s transcriptomic, metabolomic, and biochemical states and promote plant acclimation, tolerance, and survival. Here, we provide a comprehensive review of the ROS, hormones, and their joint role in shaping a plant’s responses to high and low temperatures, and we conclude by outlining hormone/ROS-regulated plant responsive strategies for developing stress-tolerant crops to combat temperature changes.
3-O-caffeoylquinic acid, also known as chlorogenic acid (CGA), functions as an intermediate in lignin biosynthesis in the phenylpropanoid pathway. It is widely distributed among numerous plant ...species and acts as an antioxidant in both plants and animals.
Using GC-MS, we discovered consistent and extreme variation in CGA content across a population of 739 4-yr-old Populus trichocarpa accessions. We performed genome-wide association studies (GWAS) from 917 P. trichocarpa accessions and expression-based quantitative trait loci (eQTL) analyses to identify key regulators.
The GWAS and eQTL analyses resolved an overlapped interval encompassing a hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyl transferase 2 (PtHCT2) that was significantly associated with CGA and partiallycharacterized metabolite abundances. PtHCT2 leaf expression was significantly correlated with CGA abundance and it was regulated by cis-eQTLs containing W-box for WRKY binding. Among all nine PtHCT homologs, PtHCT2 is the only one that responds to infection by the fungal pathogen Sphaerulina musiva (a Populus pathogen). Validation using protoplast-based transient expression system suggests that PtHCT2 is regulated by the defense-responsive WRKY.
These results are consistent with reports of CGA functioning as an antioxidant in response to biotic stress. This study provides insights into data-driven and omics-based inference of gene function in woody species.
Serum resistance is a poorly understood but common trait of some difficult-to-treat pathogenic strains of bacteria. Here, we report that glycine, serine and threonine catabolic pathway is ...down-regulated in serum-resistant Escherichia coli, whereas exogenous glycine reverts the serum resistance and effectively potentiates serum to eliminate clinically-relevant bacterial pathogens in vitro and in vivo. We find that exogenous glycine increases the formation of membrane attack complex on bacterial membrane through two previously unrecognized regulations: 1) glycine negatively and positively regulates metabolic flux to purine biosynthesis and Krebs cycle, respectively. 2) α-Ketoglutarate inhibits adenosine triphosphate synthase, which in together promote the formation of cAMP/CRP regulon to increase the expression of complement-binding proteins HtrE, NfrA, and YhcD. The results could lead to effective strategies for managing the infection with serum-resistant bacteria, an especially valuable approach for treating individuals with weak acquired immunity but a normal complement system.
Members of the transient receptor potential (TRP) ion channels conduct cations into cells. They mediate functions ranging from neuronally mediated hot and cold sensation to intracellular organellar ...and primary ciliary signaling. Here we report a cryo-electron microscopy (cryo-EM) structure of TRPC4 in its unliganded (apo) state to an overall resolution of 3.3 Å. The structure reveals a unique architecture with a long pore loop stabilized by a disulfide bond. Beyond the shared tetrameric six-transmembrane fold, the TRPC4 structure deviates from other TRP channels with a unique cytosolic domain. This unique cytosolic N-terminal domain forms extensive aromatic contacts with the TRP and the C-terminal domains. The comparison of our structure with other known TRP structures provides molecular insights into TRPC4 ion selectivity and extends our knowledge of the diversity and evolution of the TRP channels.
We develop a new approach and employ it to establish the global existence and nonlinear structural stability of attached weak transonic shocks in steady potential flow past three-dimensional wedges; ...in particular, the restriction that the perturbations are away from the wedge edge in the previous results is removed. One of the key ingredients is to identify a
good
direction of the boundary operator of a boundary condition of the shock along the wedge edge, based on the non-obliqueness of the boundary condition for the weak shock on the edge. With the identification of this direction, an additional boundary condition on the wedge edge can be assigned to make sure that the shock is attached on the edge and linearly stable under small perturbations. Based on the linear stability, we introduce an iteration scheme and prove that there exists a unique fixed point of the iteration scheme, which leads to the global existence and nonlinear structural stability of the attached weak transonic shock. This approach is based on neither the hodograph transformation nor the spectrum analysis, and should be useful for other problems with similar difficulties.
Flexible electronics is an emerging and promising technology for next generation of optoelectronic devices. Herein, hierarchical three-dimensional ZnCo2O4 nanowire arrays/carbon cloth composites were ...synthesized as high performance binder-free anodes for Li-ion battery with the features of high reversible capacity of 1300–1400 mAh g–1 and excellent cycling ability even after 160 cycles with a capacity of 1200 mAh g–1. Highly flexible full batteries were also fabricated, exhibiting high flexibility, excellent electrical stability, and superior electrochemical performances.
We are concerned with a global existence theory for finite‐energy solutions of the multidimensional Euler‐Poisson equations for both compressible gaseous stars and plasmas with large initial data of ...spherical symmetry. One of the main challenges is the strengthening of waves as they move radially inward towards the origin, especially under the self‐consistent gravitational field for gaseous stars. A fundamental unsolved problem is whether the density of the global solution forms a delta measure (i.e., concentration) at the origin. To solve this problem, we develop a new approach for the construction of approximate solutions as the solutions of an appropriately formulated free boundary problem for the compressible Navier‐Stokes‐Poisson equations with a carefully adapted class of degenerate density‐dependent viscosity terms, so that a rigorous convergence proof of the approximate solutions to the corresponding global solution of the compressible Euler‐Poisson equations with large initial data of spherical symmetry can be obtained. Even though the density may blow up near the origin at a certain time, it is proved that no delta measure (i.e., concentration) in space‐time is formed in the vanishing viscosity limit for the finite‐energy solutions of the compressible Euler‐Poisson equations for both gaseous stars and plasmas in the physical regimes under consideration.
Purpose
Microvascular invasion (MVI) is a valuable predictor of survival in hepatocellular carcinoma (HCC) patients. This study developed predictive models using eXtreme Gradient Boosting (XGBoost) ...and deep learning based on CT images to predict MVI preoperatively.
Methods
In total, 405 patients were included. A total of 7302 radiomic features and 17 radiological features were extracted by a radiomics feature extraction package and radiologists, respectively. We developed a XGBoost model based on radiomics features, radiological features and clinical variables and a three-dimensional convolutional neural network (3D-CNN) to predict MVI status. Next, we compared the efficacy of the two models.
Results
Of the 405 patients, 220 (54.3%) were MVI positive, and 185 (45.7%) were MVI negative. The areas under the receiver operating characteristic curves (AUROCs) of the Radiomics-Radiological-Clinical (RRC) Model and 3D-CNN Model in the training set were 0.952 (95% confidence interval (CI) 0.923–0.973) and 0.980 (95% CI 0.959–0.993), respectively (
p
= 0.14). The AUROCs of the RRC Model and 3D-CNN Model in the validation set were 0.887 (95% CI 0.797–0.947) and 0.906 (95% CI 0.821–0.960), respectively (
p
= 0.83). Based on the MVI status predicted by the RRC and 3D-CNN Models, the mean recurrence-free survival (RFS) was significantly better in the predicted MVI-negative group than that in the predicted MVI-positive group (RRC Model: 69.95 vs. 24.80 months,
p
< 0.001; 3D-CNN Model: 64.06 vs. 31.05 months,
p
= 0.027).
Conclusion
The RRC Model and 3D-CNN models showed considerable efficacy in identifying MVI preoperatively. These machine learning models may facilitate decision-making in HCC treatment but requires further validation.
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