Improving crop nutrient ef ficiency becomes an essential consideration for environmentally friendly and sustainable agriculture. Plant growth and development is dependent on 17 essential nutrient ...elements,among them,nitrogen（N） and phosphorus（P） are the two most important mineral nutrients. Hence it is not surprising that low N and/or low P availability in soils severely constrains crop growth and productivity,and thereby have become high priority targets for improving nutrient ef ficiency in crops. Root exploration largely determines the ability of plants to acquire mineral nutrients from soils. Therefore,root architecture,the 3-dimensional con figuration of the plant＇s root system in the soil,is of great importance for improving crop nutrient ef ficiency. Furthermore,the symbiotic associations between host plants and arbuscular mycorrhiza fungi/rhizobial bacteria,are additional important strategies to enhance nutrient acquisition. In this review,we summarize the recent advances in the current understanding of crop species control of root architecture alterations in response to nutrient availability and root/microbe symbioses,through gene or QTL regulation,which results in enhanced nutrient acquisition.
The study developed a memory task training system using functional near-infrared spectroscopy (fNIRS) and neurofeedback mechanisms, and acquired and analyzed subjects' EEG signals. The results showed ...that subjects participating in the neurofeedback task had higher correlated brain network node degrees and average cluster coefficients in the right hemisphere brain region of the prefrontal lobe, with relatively lower dispersion of mediator centrality. In addition, the subjects' left hemisphere brain region of the prefrontal lobe section had increased centrality in the neurofeedback task. Classification of brain data by the channel network model and the support vector machine model showed that the classification accuracy of both models was higher in the task state and resting state than in the feedback task and the control task, and the classification accuracy of the channel network model was higher. The results suggested that subjects in the neurofeedback task had distinct brain data features and that these fea
•Unsaturated flow in highly fractured rock system was simulated by a 3D FE algorithm.•Fractures were modeled practically by the zero-thickness elements and drainage holes interpreted as line ...elements.•The proposed method was validated by comparison with other numerical solutions and experimental data.•Seepage field in fractured rock slope system with different fracture patterns was evaluated.
It is computationally difficult to model unsaturated flow through a highly fractured rock system that contains porous rock matrix, densely distributed fracture networks and narrowly spaced drainage holes. We present an efficient numerical procedure that uses a three-dimensional, finite-element model to solve Richards’ equation with embedded zero-thickness elements for fractures and line elements for drainage holes. A mixed boundary condition is applied at potential seepage surfaces and a water retention relation with extremely narrow unsaturated zone is specified to precisely locate the phreatic surface. The procedure compares favorably with results from other numerical solutions and experimental data. A case study is developed to evaluate seepage through a densely fractured rock slope. The simulated results demonstrate that fractures disorder the hydraulic potential distribution with fracture patterns acting as significant influential factors and drainage holes dramatically lower the phreatic surface due to the effects of drainage and depressurization. The proposed numerical procedure shows to be capable of investigating the unsaturated flow in highly fractured rock mass.
Nanoparticle‐based phototherapies, such as photothermal therapy (PTT) and photodynamic therapy (PDT), exhibit strong efficacy, minimal invasion and negligible side effects in tumor treatment. These ...phototherapies have received considerable attention and been extensively studied in recent years. In addition to directly killing tumor cells through heat and reactive oxygen species, PTT and PDT can also induce various antitumor effects. In particular, the resultant massive tumor cell death after PTT and PDT triggers immune responses, including the redistribution and activation of immune effector cells, the expression and secretion of cytokines and the transformation of memory T lymphocytes. The antitumor effects can be enhanced by immune checkpoint blockage therapy. This article reviewed the recent advances of nanoparticle‐based PTT and PDT, summarized the studies on nanoparticle‐based photothermal and photodynamic immunotherapies in vitro and in vivo, and discussed challenges and future research directions.
Online product reviews may be subject to self-selection biases that impact consumer purchase behavior, online ratings' time series, and consumer surplus. This occurs if early buyers hold different ...preferences than do later consumers about the quality of a given product. Readers of early product reviews may not successfully correct for these preference differences when interpreting ratings and making purchases. In this study, we develop a model that examines how idiosyncratic preferences of early buyers can affect long-term consumer purchase behavior as well as the social welfare created by review systems. Our model provides an explanation for the structure of product ratings over time, which we empirically test using online book reviews posted on Amazon.com. Our analysis suggests that firms could benefit from altering their marketing strategies such as pricing, advertising, or product design to encourage consumers likely to yield positive reports to self-select into the market early and generate positive word-of-mouth for new products. On the other hand, self-selection bias, if not corrected, decreases consumer surplus.
Analog-to-digital converters based on sigma-delta modulators (ΣAM) are a popular choice for high resolution conversion from the analog to the digital domain. With relatively small modifications, they ...can also be used as electromechanical ΣAM (EM-ΣAM) force feedback interfaces for capacitive micro-electromechanical systems (MEMSs) inertial sensors. Such interfaces are able to combine the benefits of force feedback and analog-to-digital conversion at relatively modest circuit cost. This paper provides a comprehensive review of EM-ΣAM interfaces for capacitive MEMS inertial sensors. The principle and the design methodology of EM-ΣAM interfaces are introduced. A classification of EM-ΣAM accelerometers and gyroscopes is presented, and a detailed analysis of different EM-ΣAM architectures is given. The most representative EM-ΣAM inertial sensors systems are discussed and compared with regard to their performance characteristics. In particular, the properties of various discrete and continuous-time techniques and a system parameter optimization methodology are illustrated through specific examples. Finally, current challenges and future development trends of EM-ΣAM interfaces for inertial sensors have been identified.
In this study, a straightforward coassembly strategy is demonstrated to synthesize Pt sensitized mesoporous WO3 with crystalline framework through the simultaneous coassembly of amphiphilic ...poly(ethylene oxide)‐b‐polystyrene, hydrophobic platinum precursors, and hydrophilic tungsten precursors. The obtained WO3/Pt nanocomposites possess large pore size (≈13 nm), high surface area (128 m2 g−1), large pore volume (0.32 cm3 g−1), and Pt nanoparticles (≈4 nm) in situ homogeneously distributed in mesopores, and they exhibit excellent catalytic sensing response to CO of low concentration at low working temperature with good sensitivity, ultrashort response‐recovery time (16 s/1 s), and high selectivity. In‐depth study reveals that besides the contribution from the fast diffusion of gaseous molecules and rich interfaces in mesoporous WO3/Pt nanocomposites, the partially oxidized Pt nanoparticles that chemically and electronically sensitize the crystalline WO3 matrix, dramatically enhance the sensitivity and selectivity.
Ordered mesoporous crystalline WO3/Pt nanomaterials are synthesized through a facile straightforward coassembly strategy. Owning to combined merits of the high porosity of mesoporous WO3 and the chemical and electronic sensitization effect of Pt NPs dispersed in mesopores, the nanocomposites exhibit superior performance in carbon monoxide sensing at low working temperature.
Short and ultrashort pulse lasers offer excellent advantages in laser precision machining mainly because of their high pulse energy and low ablation threshold. The complex process of laser ...interaction with metals limits the in-depth investigation into laser ablation. Numerical simulation is important in the study of fundamental mechanisms. This review explores the start-of-the-art methods for the theoretical simulation of the laser ablation of metals, including plasma formation and expansion. Laser-induced period surface structures are also studied.
•Mechanism of both short and ultrashort pulse laser ablation of metals have been described.•Simulation methods for exploring the mechanism of short pulse laser materials interaction have been reviewed.•Current challenges and future developments of short pulse laser processing for meals have been discussed, respectively.
Research summary: Innovation requires inventors to have both new knowledge and the ability to combine and configure knowledge (i.e., combinatory knowledge), and such knowledge may flow through ...networks. We argue that both combinatory knowledge and new knowledge are accessed through collaboration networks, but that inventors' abilities to access such knowledge depends on its location in the network. Combinatory knowledge transfers from direct contacts, but not easily from indirect contacts. In contrast, new knowledge transfers from both direct and indirect contacts, but is far more likely to be new and useful when it comes from indirect contacts. Exploring knowledge flows in 69,476 patents and 89,930 unique inventors reveals evidence that combinatory knowledge from direct contacts and new knowledge from indirect contacts significantly affects innovative performance. Managerial summary: Inventors often combine ideas to create innovations. To do this, they need ideas to combine and they need the ability to combine those ideas. Inventors can get ideas to combine as well as the ability to combine ideas through prior co-workers. Prior co-workers can share ideas that may be relevant for the inventor's project and can tell the inventor about other things that other people are working on, especially people the inventor may not know. This can help inventors easily learn about ideas from friends-of-friends. The ability to combine ideas, however, is much harder to pass on. Prior co-workers must carefully work with the inventor to teach him or her the complex processes of combining ideas. This means that it is very hard to learn how to combine knowledge from a friend-of-a-friend, but it may be possible to learn from prior co-workers. We explore this phenomenon in the social relationships of software inventors.
In order to better understand the transport mechanism associated with the microstructural heterogeneity of cracked concrete composite, a modeling scheme is proposed and employed to assess the effects ...of microcracks on water permeability of concrete. Numerical samples containing 3D discrete crack network (unpercolated and percolated) with different geometric parameters (including crack density, width, length and roughness) are generated to represent the cracked concrete composite, and the effective permeability is estimated using finite element method (FEM). Extensive numerical simulations for more than 8600 concrete samples are carried out to extract the effects of microcracks on the water permeability. The results indicate that crack percolation is a determinant factor for increasing the transport properties of concrete. In addition, for concrete composite with unpercolated crack network, the influential factors to water permeability are crack density and length, while the effect from crack width is negligibly small; and for the percolated case, crack density, width and roughness are more closely correlated with the permeability of cracked composite.
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