Constructing simply nanostructured zero-,one-,and two-dimensional crystallites into threedimensional multifunctional assemblies and systems at low-cost is essential and highly challenging in ...materials science and engineering.Compared to the simply nanostructured components,a three-dimensional(3D) complex made with a precisely controlled spatial organization of all structural nanocomponents can enable us to concert functionalities from all the nanocomponents.Methodologically,so doing in nm-scales via a solution chemistry route may be much easier and less expensive than via other mechanisms.Hence,we discuss herein some recent advances in multistep solution syntheses of nanostructured 3D complexes of semiconductors with a focus mainly on their synthetic strategies and detailed mechanisms.
Emerging evidence suggests that Ca2＋ signals are important for the self-renewal and differentiation of human embryonic stem ceils （hESCs）. However, little is known about the physiological and ...pharmacological properties of the Ca2＋-handling machinery in hESCs. In this study we used RT-PCR and Western blotting to analyze the expression profiles of genes encoding Ca2＋-handling proteins; we Also used confocal Ca2＋ imaging and pharmacological approaches to determine the contribution of the Ca2＋-handling machinery to the regulation of Ca2＋ signaling in hESCs. We revealed that hESCs expressed pluripotent markers and various Ca2＋-handling-related Genes. ATP-induced Ca2＋ transients in almost all hESCs were inhibited by the inositol-1,4,5-triphosphate receptor （IP3R） blocker 2-APB Or xestospongin C. In addition, Ca2＋ transients were induced by a ryanodine receptor （RyR） activator, caffeine, in 10%-15% of hESCs and were blocked by ryanodine, whereas caffeine and ATP did not have additive effects. Moreover, store-operated Ca2＋ entry （SOCE） but not voltage-operated Ca2＋ channel-mediated Ca2＋ entry was observed. Inhibition of sarco/endoplasmic reticulum （ER） Ca2＋-ATPase （SERCA） by thapsigargin induced a significant increase in the cytosolic free Ca2＋ concentration （Ca2＋i）. For the Ca2＋ extrusion pathway. In hibition of plasma membrane Ca2＋ pumps （PMCAs） by carboxyeosin induced a slow increase in Ca2＋i, whereas the Na＋/Ca2＋ exchanger （NCX） inhibitor KBR7943 induced a rapid increase in Ca2＋i. Taken together, increased Ca2＋i is mainly mediated by Ca2＋ release from intracellular stores via IP3Rs. In addition, RyRs function in a portion of hESCs, thus indicating heterogeneity of the Ca2＋- Signaling machinery in hESCs; maintenance of low Ca2＋i is mediated by uptake of cytosolic Ca2＋ into the ER via SERCA and extrusion of Ca2＋ out of cells via NCX and PMCA in hESCs.
•An asynchronous parallel disassembly planning problem is considered.•The problem is nonlinear and highly operation time-dependent.•The disassembly model improves coordination among multiple ...operators.•We propose an improved genetic algorithm for this problem.•Proposed approach obtains shorter disassembly time than existing methods.
Disassembly is one of the most crucial remanufacturing activities. Disassembly sequence planning (DSP) is a combinatorial optimization problem and has been studied by many researchers. Conventional DSP techniques focus on sequential disassembly planning (SDP) in which only one manipulator is used to remove a single part or subassembly at a time such that it is inefficient when disassembling large or complex products. Recently, parallel disassembly has attracted some interest as it employs several manipulators to remove multiple components simultaneously. However, most of the work to date focuses on parallel disassembly techniques which require synchronization between manipulators, i.e., they must start their tasks simultaneously. This simplifies the modeling and analysis efforts but fails to fully realize the benefits of parallel disassembly. In this work, we propose asynchronous parallel disassembly planning (aPDP) which eliminates the synchronization requirement. In addition to precedence constraints, aPDP becomes highly operation time-dependent. To deal with this, we design an efficient encoding and decoding strategy for the disassembly process. In this paper, a metaheuristic approach, based on a genetic algorithm, is developed to solve the aPDP problem. The proposed algorithm is applied to four products which require disassembly processes of varying complexity, and the results are compared with two methods reported in literature. It is suggested that the proposed approach can identify faster disassembly processes, especially when solving large-scale problems.
Highly Automated Vehicles (HAVs) must undergo strict safety testing before being released to the public. Mileage-based on-road testing suffers from unaffordable time costs and high safety risks. ...Simulated scenario-based testing has been found to be a trustworthy alternative for testing HAVs' built-in algorithms and functionalities. Test automation is typically used to generate target scenarios. This approach facilitates customized testing and avoids wasting time on simple and redundant scenarios. This study aims to review test automation methods and discuss how to accentuate their strengths rather than be trapped in their weaknesses under certain applicable conditions. According to their main purposes, we classify test automation methods into coverage-oriented, unsafe-scenario-oriented, and naturalistic-assessment-oriented categories. To further demonstrate the differences of these methods, we then design numerical experiment to compare the capabilities of seven test automation methods. Finally, we compile our observations to form a comprehensive guide for selecting test automation methods with different test requirements in mind.
Live-cell Raman imaging based on bioorthogonal Raman probes with distinct signals in the cellular Raman-silent region (1800-2800 cm
) has attracted great interest in recent years. We report here a ...class of water-soluble and biocompatible polydiacetylenes with intrinsic ultrastrong alkyne Raman signals that locate in this region for organelle-targeting live-cell Raman imaging. Using a host-guest topochemical polymerization strategy, we have synthesized a water-soluble and functionalizable master polydiacetylene, namely poly(deca-4,6-diynedioic acid) (PDDA), which possesses significantly enhanced (up to ~10
fold) alkyne vibration compared to conventional alkyne Raman probes. In addition, PDDA can be used as a general platform for multi-functional ultrastrong Raman probes. We achieve high quality live-cell stimulated Raman scattering imaging on the basis of modified PDDA. The polydiacetylene-based Raman probes represent ultrastrong intrinsic Raman imaging agents in the Raman-silent region (without any Raman enhancer), and the flexible functionalization of this material holds great promise for its potential diverse applications.
Under climate change, drought is one of the most limiting factors that influences wheat (
L.) production. Exploring stress-related genes is vital for wheat breeding. To identify genes related to the ...drought tolerance response, two common wheat cultivars, Zhengmai 366 (ZM366) and Chuanmai 42 (CM42), were selected based on their obvious difference in root length under 15% PEG-6000 treatment. The root length of the ZM366 cultivar was significantly longer than that of CM42. Stress-related genes were identified by RNA-seq in samples treated with 15% PEG-6000 for 7 days. In total, 11,083 differentially expressed genes (DEGs) and numerous single nucleotide polymorphisms (SNPs) and insertions/deletions (InDels) were identified. GO enrichment analysis revealed that the upregulated genes were mainly related to the response to water, acidic chemicals, oxygen-containing compounds, inorganic substances, and abiotic stimuli. Among the DEGs, the expression levels of 16 genes in ZM366 were higher than those in CM42 after the 15% PEG-6000 treatment based on RT-qPCR. Furthermore, EMS-induced mutants in Kronos (
L.) of 4 representative DEGs possessed longer roots than the WT after the 15% PEG-6000 treatment. Altogether, the drought stress genes identified in this study represent useful gene resources for wheat breeding.
Automated Vehicles (AVs) need to be thoroughly evaluated in order to ensure their driving capabilities. However, comprehensive evaluations are intractable due to both time and monetary costs. To ...address this problem, we propose an Adaptive Design of Experiments (ADOE) method to evaluate the safety of AVs. Using this method, a Surrogate Model (SM) is established and updated iteratively. SM in ADOE is used to approximate the results of AV testing and help to select the next concrete scenario to be tested in each iteration. Two different ADOE approaches are proposed in this study for different testing purposes. Since the choice of the surrogate model has a profound impact on the performance of the ADOE method, 6 surrogate models were compared with two logical scenarios at different scales - a car following logical scenario and a cut-in logical scenario. Results show that Extreme Gradient Boosting (XGB) is suitable for both ADOE approaches. And both proposed ADOE approaches achieved desired performance. Scenario-oriented ADOE made full use of each concrete scenario, capturing one collision case for every 1.12 test runs in the car following logical scenario, while SM-oriented ADOE successfully depicted the boundary between safety and danger. Using 0.46% test resources compared to enumeration, the SM-oriented ADOE found 93.9% dangerous scenarios with 90.9% precision. ADOE approaches have great potential in accelerating the evaluation of AV safety.
Remanufacturing, a process returning used products to at least as good as new condition, is increasingly recognized as an important part of the circular economy. Since returned used components for ...remanufacturing have varying conditions and different defects, remanufacturing is very time-consuming and labor-intensive. There is an urgent need to reuse knowledge generated from existing parts remanufacturing to rapidly create sound process planning for the new arrival of used parts. A hybrid method combing rough set (RS) and cased-based reasoning (CBR) for remanufacturing process planning is presented in this paper. RS is employed for features reduction and rapid determination of features’ weights automatically, and CBR is utilized to calculate the similarity of process cases to identify the most suitable solution effectively from case database. The application of the methodology is demonstrated in an example of remanufacturing process for a saddle guide. The results indicated that the quality of remanufactured products has been improved significantly. The method has been implemented in a prototype system using Visual Studio 2010 and Microsoft SQL Server2008. The results suggested that the hybrid RS–CBR system is feasible and effective for the rapid generation of sound process planning for remanufacturing.
In recent years, Microcystis aeruginosa blooms have occurred throughout the world, causing huge economic losses and destroying aquatic ecosystems. It is necessary to develop effective and ecofriendly ...methods to control M. aeruginosa blooms. Here, we report a high algicidal activity of prodigiosin (PG) against M. aeruginosa as well as the algicidal mechanism. PG showed high algicidal activity against M. aeruginosa, with a 50% lethal dose (LD
) of 5.87 μg/mL in 72 h. A combination of methods, including propidium iodide and Annexin V-fluorescein staining assays and light and electron microscopy indicated the existence of two modes of cell death with features similar to those in eukaryotic programmed cell death: necrotic-like and apoptotic-like. Biochemical and physiological analyses showed that PG generates reactive oxygen species (ROS), which induce lipid peroxidation, damage the membrane system and destroy the function of the photosystem. A proteomics analysis revealed that many proteins were differentially expressed in response to PG stress and that most of these proteins were involved in important metabolic processes, which may trigger necrotic-like or apoptotic-like cell death. The present study sheds light on the multiple toxicity mechanisms of PG on M. aeruginosa and its potential for controlling the occurrence of M. aeruginosa blooms in lakes.
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