Kaempferol (kae) and its glycosides are widely distributed in nature and show multiple bioactivities, yet few reports have compared them. In this paper, we report the antitumor, antioxidant and ...anti-inflammatory activity differences of kae, kae-7-O-glucoside (kae-7-O-glu), kae-3-O-rhamnoside (kae-3-O-rha) and kae-3-O-rutinoside (kae-3-O-rut). Kae showed the highest antiproliferation effect on the human hepatoma cell line HepG2, mouse colon cancer cell line CT26 and mouse melanoma cell line B16F1. Kae also significantly inhibited AKT phosphorylation and cleaved caspase-9, caspase-7, caspase-3 and PARP in HepG2 cells. A kae-induced increase in DPPH and ABTS radical scavenging activity, inhibition of concanavalin A (Con A)-induced activation of T cell proliferation and NO or ROS production in LPS-induced RAW 264.7 macrophage cells were also seen. Kae glycosides were used to produce kae via environment-friendly enzymatic hydrolysis. Kae-7-O-glu and kae-3-O-rut were hydrolyzed to kae by β-glucosidase and/or α-L-rhamnosidase. This paper demonstrates the application of enzymatic catalysis to obtain highly biologically active kae. This work provides a novel and efficient preparation of high-value flavone-related products.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
In order to improve the resolution ability of the cable inspection robot in the dark environment of the tunnel and enable it to complete the autonomous obstacle avoidance control, a new ...intelligent obstacle crossing control method for the tunnel cable inspection track robot is studied, and the working environment of the inspection robot is explored, the Denavit-Hartenberg parameter method is used to establish the obstacle crossing model of the inspection robot, the joint variables of each robot are analyzed, and the position and posture of the end effector of the robot are obtained. The minimum value of the sum of moments is obtained by using the approximate solution method, and the winding deflection and torsion angle of the inspection robot is calculated by reverse solution. The robot obstacle-crossing motion workspace is analyzed by using the optimization algorithm, and the three-dimensional coordinate system is established. It is decomposed into the X-Y coordinate system, Y-Z coordinate system, and x-z coordinate system, so as to determine the maximum distance that the end gripper pops up on each axis, and judge whether the inspection robot can achieve obstacle crossing. According to the feedback results, intelligent control is carried out, and experiments are designed to verify the effectiveness of the control method. The results show that the voltage value of the inspection robot obtained by the control method is closer to the theoretical value, which can effectively help the robot to achieve obstacle-climbing operation accurately.
An ultrasensitive fluorescent biosensor is reported for glucose detection based on a Fenton-like reaction triggered chemical redox-cycling signal amplification strategy. In this amplified strategy, ...Cu2+ oxidizes chemically o-phenylenediamine (OPD) to generate photosensitive 2,3-diaminophenazine (DAP) and Cu+/Cu0. On the one hand, the generated Cu0 catalyzes the oxidation of OPD. On the other hand, H2O2 reacts with Cu+ to produce hydroxyl radicals (·OH) and Cu2+ through a Cu+-mediated Fenton-like reaction. The generated ·OH and recycled Cu2+ ions take turns oxidizing OPD to produce more photoactive DAP, triggering a self-sustaining chemical redox-cycling reaction and a remarkable fluorescent enhancement. It is worth mentioning that the cascade reaction did not stop until OPD molecules were completely consumed. Benefiting from H2O2-triggered chemical redox-cycling signal amplification, the strategy was exploited for the development of an ultrasensitive fluorescent biosensor for glucose determination. Glucose content monitoring was realized with a linear range from 1 nM to 1 μM and a limit of detection of 0.3 nM. This study validates the practicability of the chemical redox-cycling signal amplification on the fluorescent bioanalysis of glucose in human serum samples. It is expected that the method offers new opportunities to develop ultrasensitive fluorescent analysis strategy.
GCaMP, one popular type of genetically-encoded Ca
indicator, has been associated with various side-effects. Here we unveil the intrinsic problem prevailing over different versions and applications, ...showing that GCaMP containing CaM (calmodulin) interferes with both gating and signaling of L-type calcium channels (Ca
1). GCaMP acts as an impaired apoCaM and Ca
/CaM, both critical to Ca
1, which disrupts Ca
dynamics and gene expression. We then design and implement GCaMP-X, by incorporating an extra apoCaM-binding motif, effectively protecting Ca
1-dependent excitation-transcription coupling from perturbations. GCaMP-X resolves the problems of detrimental nuclear accumulation, acute and chronic Ca
dysregulation, and aberrant transcription signaling and cell morphogenesis, while still demonstrating excellent Ca
-sensing characteristics partly inherited from GCaMP. In summary, CaM/Ca
1 gating and signaling mechanisms are elucidated for GCaMP side-effects, while allowing the development of GCaMP-X to appropriately monitor cytosolic, submembrane or nuclear Ca
, which is also expected to guide the future design of CaM-based molecular tools.
Scanning probe lithography (SPL) is a versatile nanofabrication method that employs a scanning probe microscope (SPM) to generate patterns and nanoscale structures on surfaces. Typically, an atomic ...force microscope (AFM) is the preferred type of SPM for nanolithography and in situ characterization based on the probe-sample interaction. However, the maximum area of the existing SPL is mainly limited by scanner stroke of the AFM and usually less than <inline-formula><tex-math notation="LaTeX">100\times 100</tex-math></inline-formula> μm<inline-formula><tex-math notation="LaTeX">^{2}</tex-math></inline-formula>. Ultralarge-area nanofabrication can be achieved by using a "step and scan" manner but leading to stitching errors and low throughput. This article proposes a novel ultralarge-area stitchless SPL and high-throughput in situ characterization system utilizing a leaf spring-based nanomanipulator, which offers a maximum scanning area of <inline-formula><tex-math notation="LaTeX">2\times 2</tex-math></inline-formula> mm<inline-formula><tex-math notation="LaTeX">^{2}</tex-math></inline-formula>. Further, we propose a novel optimized passband loss filter for the repetitive control of the nanomanipulator to realize high-bandwidth and high-precision trajectory tracking. Experimental results indicate that the proposed control method achieves satisfactory tracking performance for a triangular wave with an amplitude of 500 μm. Compared with the existing SPL systems, we achieve stitchless nanolithography at a speed of <inline-formula><tex-math notation="LaTeX">\sim </tex-math></inline-formula>2 mm/s and high-throughput in situ characterization in the range of <inline-formula><tex-math notation="LaTeX">500\times 500</tex-math></inline-formula> μm<inline-formula><tex-math notation="LaTeX">^{2}</tex-math></inline-formula>. This system opens up significant avenues for the research and application of ultralarge-area nanofabrication and in situ characterization.
Most of the state governments in United States (U.S.) issued lockdown or business restrictions amid the COVID-19 pandemic in March 2020, which created a unique opportunity to evaluate the air quality ...response to reduced economic activities. Data acquired from 28 long-term air quality stations across the U.S. revealed widespread but nonuniform reductions of nitrogen dioxide (NO2) and carbon monoxide (CO) during the first phase of lockdown (March 15–April 25, 2020) relative to a pre-lockdown reference period and historical baselines established in 2017–2019. The reductions, up to 49% for NO2 and 37% for CO, are statistically significant at two thirds of the sites and tend to increase with local population density. Significant reductions of particulate matter (PM2.5 and PM10) only occurred in the Northeast and California/Nevada metropolises where NO2 declined the most, while the changes in ozone (O3) were mixed and relatively minor. These findings are consistent with lower transportation and utility demands that dominate NO2 and CO emissions, especially in major urban areas, due to the lockdown. This study provides an insight into potential public health benefits with more aggressive air quality management, which should be factored into strategies to reopen the U.S. and global economy.
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•The lockdown issued due to COVID-19 had nonuniformly impacted air quality in the US.•Consistent NO2 and CO declines corroborate with low transportation/utility demands.•Reductions in NO2 ranged 5–49% and tended to increase with local population density.•Significant PM reductions only occurred where NO2 declined the most.•The impact on O3 was mixed, generally within ±20%.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In recent years, there has been a growing interest in the detection, location, and classification (DLC) of multiple dipole-like magnetic sources based on magnetic gradient tensor (MGT) data. In these ...applications, the tilt angle is usually used to detect the number of sources. We found that the tilt angle is only suitable for the scenario where the positive and negative signs of the magnetic sources' inclination are the same. Therefore, we map the L2 norm of the vertical magnetic gradient tensor on the arctan function, denoted as the VMGT2 angle, to detect the number of sources. Then we use the normalized source strength (NSS) to narrow the parameters' search space and combine the differential evolution (DE) algorithm with the Levenberg-Marquardt (LM) algorithm to solve the sources' locations and magnetic moments. Simulation experiments and a field demonstration show that the VMGT2 angle is insensitive to the sign of inclination and more accurate in detecting the number of magnetic sources than the tilt angle. Meanwhile, our method can quickly locate and classify magnetic sources with high precision.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Abstract
A fuzzy cognitive map based behavior planning method for mobile robot is proposed in this paper. Aiming at the intelligentialize advanced application problems of power substation equipment ...inspection robot, a logical structure of inspection tasks planning based on hierarchical hybrid complex system is presented, and the operating principle of task decomposition and task planning are given in detail. The dependent events in inspecting tasks are considered as concept nodes to present the connection weights between nodes and establish the fuzzy cognitive map model of task and behavior planning, so as to realize task decomposition and generate the action logic sequences. Meanwhile, the action sequences can be adjusted in real time with the sensor information. The proposed method is simple without introducing complicated calculations and much training. Simulation results verify the feasibility and effectiveness.
Core–shell structures, where the “guest” material is encapsulated within a protective shell, integrate the advantages of different materials to enhance the overall properties of the composite. ...Covalent–organic frameworks (COFs) are favorable candidates for composing core–shell structures due to their inherent porosity, good activity, excellent stability, and other advantages. In particular, COFs as shells to encapsulate other functional materials are becoming increasingly popular in the fields of environmental remediation and energy conversion. However, there is a lack of reviews on COF‐based core–shell materials. In this context, this review provides a systematic summary of the current research on COF‐based core–shell composites. First, a simple classification is made for COF‐based core–shell composites. The second part of the review describes the main synthesis methods. The changes brought about by the COF shell and core–shell structures on the properties of the composites and their applications in photocatalysis, electrocatalysis, adsorption, sensing, and supercapacitors are then emphasized. Finally, new perspectives on the future development and challenges of composites are presented. The purpose of this study is to provide future insights into the design and application of COF‐based core–shell composites.
Combining covalent–organic frameworks (COFs) with other functional materials to form core–shell structures has received extensive attention from researchers due to its unique advantages. This review provides a comprehensive overview of the classification, synthesis, structure, properties, and applications in environmental and energy fields of COF‐based core–shell composites. In addition, future developments and challenges are also discussed.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The controlled assembly of nanowires is one of the key challenges in the development of a range of functional 3D aerogels with unique physicochemical properties for practical applications. However, ...the deep understanding of the dynamic assemble process for fabricating nanowire aerogels remains elusive. Herein, a facile strategy is presented for the metallic ion‐induced assembly of nanowires into macroscopic aerogels via a solution‐based process. This method enables the interconnecting between polymer‐decorated nanowires via metallic coordination, resulting in plenty of nanowire bundles with the same orientation. Besides, the coordinated binding strength of nanowires with different metallic ions is also discussed. The assembly mechanism that the metallic ions induced dynamic behavior of nanowires is revealed via molecular dynamics theoretical evaluation. These findings benefit for constructing nanowire‐based aerogels with unique structural features and multi‐function, which pave new opportunities for other material systems.
Herein, a facile strategy is presented for the metallic ion‐induced assembly of nanowires into 3D aerogels via a hydrothermal process. The coordinated binding strength of nanowires with different metallic ions as well as the metallic ions induced dynamic behavior of nanowires are revealed via molecular dynamics theoretical evaluation.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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