Synergistic regulation of intermolecular interactions to control chiral structures for chiral recognition

Understanding the regulatory mechanism of self-assembly processes is a necessity to modulate nanostructures and their properties. Herein, we have studied the mechanism of self-assembly in the C3 symmetric 1,3,5-benzentricarboxylic amino acid methyl ester enantiomers(TPE) in a mixed solvent system consisting of methanol and water. The resultant chiral structure was used for chiral recognition. The formation of chiral structures from the synergistic effect of multiple noncovalent interaction forces was confirmed by various techniques. Molecular dynamics simulations were used to characterize the time evolution of TPE structure and properties in solution. The theoretical results were consistent with the experimental results. Furthermore, the chiral structure assembled by the building blocks of TPE molecules was highly stereoselective for diamine compounds.

Sedimentary characteristics and depositional evolution of carbonate platform during the Cambrian and Ordovician in eastern Tarim Basin,NW China

The eastern Tarim Basin(Tadong Area)has gained wide attentions on large-scale marine carbonate reservoirs in Cambrian-Ordovician due to significant hydrocarbon discoveries.A systematic analysis combining thin sections,cores,wireline logs,and seismic data is conducted on Cambrian-Ordovician carbonate platform in the whole eastern Tarim Basin,including Gucheng area,Majiaer area,and western Luobopo rise(Luoxi area).The results show that 8 sub-facies and more than 10 microfacies are developed including open platform,restricted/semi-restricted platform,reef-shoal around platform margin,drowned platform,foreslope,neritic platform,and deep-water basin.As both key areas for hosting petroleum reserves during the Cambrian and Ordovician,the Luoxi area is dominated by deep-water basin facies,while the Gucheng area is dominated by neritic platform facies and deep-water basin facies during the Lower Cambrian.The deposition evolution during the whole Cambrian is dominated by slope facies and deep-water facies,platform margin facies,and platform facies.In contrast,it is dominated by open platform facies during the whole Ordovician.The depositional evolution of carbonate platform is mainly controlled by paleo-geomorphology and sea-level changes.The distribution of paleo-geomorphologic units plays an important role in controlling types and distributions of carbonate platform facies.The transgression assists in growth of reef-shoal complex and lime mud mound in the Early Ordovician.However,with neritic platform and slope being to disappeared,in the Middle Ordovician,platform margin facies are well developed in Gucheng Area.Platform facies and deepwater basin facies are widely distributed.Finally,carbonate platform is drowned due to sea level rising in the Late Ordovician.The depositional evolution of carbonate platform coinciding falling and rising of sea-level changes can be beneficial for appropriate carbonate reservoirs identification and petroleum exploration.

Solid-state molecular dynamics of a torsion-variable ammonium embedded in a deformable supramolecular framework

Accompanied by solid-state structural phase transitions,the switchable molecular dynamics(MD)and order-disorder transformation of(i-PrNHMe2)^(+)cation embedded in a deformable{[Ni(NCS)_(6)]^(4-)}_(∞)supramolecular framework are in-depth investigated by variable-temperature tests of single-crystal X-ray diffraction,dielectric measurement,and MD simulation.Interestingly,it is found that the confined swinging or flipping of the(i-PrNHMe_(2))^(+)cation as a whole is assisted by a synergistic change of its torsion angle.This research provides a helpful insight into the solid-state MD of moderate-sized quasi-spherical molecules/ions that feature a flexible inner core.

Multispectral Drone Imagery and SRGAN for Rapid Phenotypic Mapping of Individual Chinese Cabbage Plants

The phenotypic parameters of crop plants can be evaluated accurately and quickly using an unmanned aerial vehicle(UAV)equipped with imaging equipment.In this study,hundreds of images of Chinese cabbage(Brassica rapa L.ssp.pekinensis)germplasm resources were collected with a low-cost UAV system and used to estimate cabbage width,length,and relative chlorophyll content(soil plant analysis development[SPAD]value).The super-resolution generative adversarial network(SRGAN)was used to improve the resolution of the original image,and the semantic segmentation network Unity Networking(UNet)was used to process images for the segmentation of each individual Chinese cabbage.Finally,the actual length and width were calculated on the basis of the pixel value of the individual cabbage and the ground sampling distance.The SPAD value of Chinese cabbage was also analyzed on the basis of an RGB image of a single cabbage after background removal.After comparison of various models,the model in which visible images were enhanced with SRGAN showed the best performance.With the validation set and the UNet model,the segmentation accuracy was 94.43%.For Chinese cabbage dimensions,the model was better at estimating length than width.The R2 of the visible-band model with images enhanced using SRGAN was greater than 0.84.For SPAD prediction,the R2 of the model with images enhanced with SRGAN was greater than 0.78.The root mean square errors of the 3 semantic segmentation network models were all less than 2.18.The results showed that the width,length,and SPAD value of Chinese cabbage predicted using UAV imaging were comparable to those obtained from manual measurements in the field.Overall,this research demonstrates not only that UAVs are useful for acquiring quantitative phenotypic data on Chinese cabbage but also that a regression model can provide reliable SPAD predictions.This approach offers a reliable and convenient phenotyping tool for the investigation of Chinese cabbage breeding traits.

Insights into the regulation of C-repeat binding factors in plant cold signaling

Cold temperatures, a major abiotic stress, threaten the growth and development of plants, worldwide. To cope with this adverse environmental cue, plants from temperate climates have evolved an array of sophisticated mechanisms to acclimate to cold periods, increasing their ability to tolerate freezing stress. Over the last decade, significant progress has been made in determining the molecular mechanisms underpinning cold acclimation, including following the identification of several pivotal components, including candidates for cold sensors, protein kinases, and transcription factors. With these developments, we have a better understanding of the CBF-dependent cold-signaling pathway. In this review, we summarize recent progress made in elucidating the cold-signaling pathways, especially the C-repeat binding factor-dependent pathway, and describe the regulatory function of the crucial components of plant cold signaling. We also discuss the unsolved questions that should be the focus of future work.

Reciprocal regulation between the negative regulator PP2CG1 phosphatase and the positive regulator OST1 kinase confers cold response in Arabidopsis

Protein phosphorylation and dephosphorylation have been reported to play important roles in plant cold responses.In addition,phospho-regulatory feedback is a conserved mechanism for biological processes and stress responses in animals and plants.However,it is less well known that a regulatory feedback loop is formed by the protein kinase and the protein phosphatase in plant responses to cold stress.Here,we report that OPEN STOMATA 1(OST1)and PROTEIN PHOSPHATASE 2C G GROUP 1(PP2CG1)reciprocally regulate the activity during the cold stress response.The interaction of PP2CG1 and OST1 is inhibited by cold stress,which results in the release of OST1 at the cytoplasm and nucleus from suppression by PP2CG1.Interestingly,cold-activated OST1 phosphorylates PP2CG1 to suppress its phosphatase activity,thereby amplifying cold signaling in plants.Mutations of PP2CG1 and its homolog PP2CG2 enhance freezing tolerance,whereas overexpression of PP2CG1 decreases freezing tolerance.Moreover,PP2CG1 negatively regulates protein levels of C-REPEAT BINDING FACTORs(CBFs)under cold stress.Our results uncover a phosphor/dephosphor-regulatory feedback loop mediated by PP2CG1 phosphatase and OST1 protein kinase in plant cold responses.

Multispectral Drone Imagery and SRGAN for Rapid Phenotypic Mapping of Individual Chinese Cabbage Plants

The phenotypic parameters of crop plants can be evaluated accurately and quickly using an unmanned aerial vehicle(UAV)equipped with imaging equipment.In this study,hundreds of images of Chinese cabbage(Brassica rapa L.ssp.pekinensis)germplasm resources were collected with a low-cost UAV system and used to estimate cabbage width,length,and relative chlorophyll content(soil plant analysis development[SPAD]value).The super-resolution generative adversarial network(SRGAN)was used to improve the resolution of the original image,and the semantic segmentation network Unity Networking(UNet)was used to process images for the segmentation of each individual Chinese cabbage.

Fault-line selection and fault-type recognition in DC systems based on graph theory

When a fault occurs in a DC system,the fault current rises rapidly with no zero-crossing point which makes fault-line selection and fault-type identification difficult.In this paper,an online detection and protection method based on graph theory,namely the“double D method”,is proposed for fault-line selection and fault-type identification in DC systems.In the proposed method,the entire distribution network is visualized as a“map”with vertices representing the line convergence points and edges representing the connection lines.A network topology matrix“D”is formed by detecting the current directions as the current directions are altered following a fault,whereas the current directions at the ends of non-fault lines remain the same.In order to prevent misjudgment problems arising from power flow reversal,the rates of change of the fault currents are used to further determine whether a fault has occurred and the“double D method”is introduced to identify the fault type.Simulations results with different fault types verify the effectiveness and reliability of the proposed method.

Study on the mechanical properties of outwash deposits with random structure method

Outwash deposit is one of the major threats to the safety and stability of railway transit engineering in the Sichuan–Tibet area.In this paper,different samples of outwash deposits were prepared based on the random structure method,and a series of large-scale direct shear tests were carried out under different normal stresses.The influence of stone content and the spatial distribution of stone blocks on the physical and mechanical properties of outwash deposits were studied.The results show that with the increase of stone content,the shear stress-displacement curve changs from strain softening to strain hardening.The shear zone is larger,and its shape is more tortuous due to the movement and rotation of stone blocks.The internal frictional angle increases linearly while the cohesion diseases with the increase of stone content.The main influence of the spatial distribution of stone blocks on the mechanical properties of outwash deposits is the peak stress.The shear zone is mainly determined by the distribution of the stone blocks near the shear zone.