With the extensive adoption of artificial intelligence (AI), construction engineering and management (CEM) is experiencing a rapid digital transformation. Since AI-based solutions in CEM has become ...the current research focus, it needs to be comprehensively understood. In this regard, this paper presents a systematic review under both scientometric and qualitative analysis to present the current state of AI adoption in the context of CEM and discuss its future research trends. To begin with, a scientometric review is performed to explore the characteristics of keywords, journals, and clusters based on 4,473 journal articles published in 1997–2020. It is found that there has been an explosion of relevant papers especially in the past 10 years along with the change in keyword popularity from expert systems to building information modeling (BIM), digital twins, and others. Then, a brief understanding of CEM is provided, which can be benefited from the emerging trend of AI in terms of automation, risk mitigation, high efficiency, digitalization, and computer vision. Special concerns have been put on six hot research topics that amply the advantage of AI in CEM, including (1) knowledge representation and reasoning, (2) information fusion, (3) computer vision, (4) natural language processing, (5) intelligence optimization, and (6) process mining. The goal of these topics is to model, predict, and optimize issues in a data-driven manner throughout the whole lifecycle of the actual complex project. To further narrow the gap between AI and CEM, six key directions of future researches, such as smart robotics, cloud virtual and augmented reality (cloud VR/AR), Artificial Intelligence of Things (AIoT), digital twins, 4D printing, and blockchains, are highlighted to constantly facilitate the automation and intelligence in CEM.
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•A systematic review under both scientometric and qualitative analysis for the topic is provided.•A scientometric review is performed on 4,473 journal articles published in 1997–2020.•AI’s main benefits including modeling and pattern detection, prediction, and optimization•Special concerns have been put on six state-of-the-art applications of AI in CEM.•Key directions of future studies, like smart robotics, digital twins, and blockchains are provided.
Channelopathies in fragile X syndrome Deng, Pan-Yue; Klyachko, Vitaly A
Nature reviews. Neuroscience,
05/2021, Letnik:
22, Številka:
5
Journal Article
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Fragile X syndrome (FXS) is the most common inherited form of intellectual disability and the leading monogenic cause of autism. The condition stems from loss of fragile X mental retardation protein ...(FMRP), which regulates a wide range of ion channels via translational control, protein-protein interactions and second messenger pathways. Rapidly increasing evidence demonstrates that loss of FMRP leads to numerous ion channel dysfunctions (that is, channelopathies), which in turn contribute significantly to FXS pathophysiology. Consistent with this, pharmacological or genetic interventions that target dysregulated ion channels effectively restore neuronal excitability, synaptic function and behavioural phenotypes in FXS animal models. Recent studies further support a role for direct and rapid FMRP-channel interactions in regulating ion channel function. This Review lays out the current state of knowledge in the field regarding channelopathies and the pathogenesis of FXS, including promising therapeutic implications.
Genetic and genomic studies have advanced our knowledge of inherited Parkinson's disease (PD), however, the etiology and pathophysiology of idiopathic PD remain unclear. Herein, we perform a ...meta-analysis of 8 PD postmortem brain transcriptome studies by employing a multiscale network biology approach to delineate the gene-gene regulatory structures in the substantia nigra and determine key regulators of the PD transcriptomic networks. We identify STMN2, which encodes a stathmin family protein and is down-regulated in PD brains, as a key regulator functionally connected to known PD risk genes. Our network analysis predicts a function of human STMN2 in synaptic trafficking, which is validated in Stmn2-knockdown mouse dopaminergic neurons. Stmn2 reduction in the mouse midbrain causes dopaminergic neuron degeneration, phosphorylated α-synuclein elevation, and locomotor deficits. Our integrative analysis not only begins to elucidate the global landscape of PD transcriptomic networks but also pinpoints potential key regulators of PD pathogenic pathways.
Peripheral sensory neurons regenerate their axon after nerve injury to enable functional recovery. Intrinsic mechanisms operating in sensory neurons are known to regulate nerve repair, but whether ...satellite glial cells (SGC), which completely envelop the neuronal soma, contribute to nerve regeneration remains unexplored. Using a single cell RNAseq approach, we reveal that SGC are distinct from Schwann cells and share similarities with astrocytes. Nerve injury elicits changes in the expression of genes related to fatty acid synthesis and peroxisome proliferator-activated receptor (PPARα) signaling. Conditional deletion of fatty acid synthase (Fasn) in SGC impairs axon regeneration. The PPARα agonist fenofibrate rescues the impaired axon regeneration in mice lacking Fasn in SGC. These results indicate that PPARα activity downstream of FASN in SGC contributes to promote axon regeneration in adult peripheral nerves and highlight that the sensory neuron and its surrounding glial coat form a functional unit that orchestrates nerve repair.
Key points
Single‐channel recordings in CA3 pyramidal neurons revealed that large‐conductance calcium‐activated K+ (BK) channel open probability was reduced by loss of fragile X mental retardation ...protein (FMRP) and that FMRP acts on BK channels by modulating the channel's gating kinetics.
Fmr1/BKβ4 double knockout mice were generated to genetically upregulate BK channel activity in the absence of FMRP.
Deletion of the BKβ4 subunit alleviated reduced BK channel open probability via increasing BK channel open frequency, but not through prolonging its open duration.
Genetic upregulation of BK channel activity via deletion of BKβ4 normalized action potential duration, excessive glutamate release and short‐term synaptic plasticity during naturalistic stimulus trains in excitatory hippocampal neurons in the absence of FMRP.
Genetic upregulation of BK channel activity via deletion of BKβ4 was sufficient to normalize excessive epileptiform activity in an in vitro model of seizure activity in the hippocampal circuit in the absence of FMRP.
Loss of fragile X mental retardation protein (FMRP) causes fragile X syndrome (FXS), yet the mechanisms underlying the pathophysiology of FXS are incompletely understood. Recent studies identified important new functions of FMRP in regulating neural excitability and synaptic transmission via both translation‐dependent mechanisms and direct interactions of FMRP with a number of ion channels in the axons and presynaptic terminals. Among these presynaptic FMRP functions, FMRP interaction with large‐conductance calcium‐activated K+ (BK) channels, specifically their auxiliary β4 subunit, regulates action potential waveform and glutamate release in hippocampal and cortical pyramidal neurons. Given the multitude of ion channels and mechanisms that mediate presynaptic FMRP actions, it remains unclear, however, to what extent FMRP–BK channel interactions contribute to synaptic and circuit defects in FXS. To examine this question, we generated Fmr1/β4 double knockout (dKO) mice to genetically upregulate BK channel activity in the absence of FMRP and determine its ability to normalize multilevel defects caused by FMRP loss. Single‐channel analyses revealed that FMRP loss reduced BK channel open probability, and this defect was compensated in dKO mice. Furthermore, dKO mice exhibited normalized action potential duration, glutamate release and short‐term dynamics during naturalistic stimulus trains in hippocampal pyramidal neurons. BK channel upregulation was also sufficient to correct excessive seizure susceptibility in an in vitro model of seizure activity in hippocampal slices. Our studies thus suggest that upregulation of BK channel activity normalizes multi‐level deficits caused by FMRP loss.
Key points
Single‐channel recordings in CA3 pyramidal neurons revealed that large‐conductance calcium‐activated K+ (BK) channel open probability was reduced by loss of fragile X mental retardation protein (FMRP) and that FMRP acts on BK channels by modulating the channel's gating kinetics.
Fmr1/BKβ4 double knockout mice were generated to genetically upregulate BK channel activity in the absence of FMRP.
Deletion of the BKβ4 subunit alleviated reduced BK channel open probability via increasing BK channel open frequency, but not through prolonging its open duration.
Genetic upregulation of BK channel activity via deletion of BKβ4 normalized action potential duration, excessive glutamate release and short‐term synaptic plasticity during naturalistic stimulus trains in excitatory hippocampal neurons in the absence of FMRP.
Genetic upregulation of BK channel activity via deletion of BKβ4 was sufficient to normalize excessive epileptiform activity in an in vitro model of seizure activity in the hippocampal circuit in the absence of FMRP.
In the rapidly developing areas of nanobiotechnology, magnetic nanoparticles (MNPs) are one type of the most well-established nanomaterials because of their biocompatibility and the potential ...applications as alternative contrast enhancing agents for magnetic resonance imaging (MRI). While the development of MNPs as alternative contrast agents for MRI application has moved quickly to testing in animal models and clinical trials, other applications of biofunctional MNPs have been explored extensively at the stage of qualitative or conceptual demonstration. In this critical review, we summarize the development of two straightforward applications of biofunctional MNPs--manipulating proteins and manipulating cells--in the last five years or so and hope to provide a relatively comprehensive assessment that may help the future developments. Specifically, we start with the examination of the strategy for the surface functionalization of MNPs because the applications of MNPs essentially depend on the molecular interactions between the functional molecules on the MNPs and the intended biological targets. Then, we discuss the use of MNPs for manipulating proteins since protein interactions are critical for biological functions. Afterwards, we evaluate the development of the use of MNPs to manipulate cells because the response of MNPs to a magnetic field offers a unique way to modulate cellular behavior in a non-contact or "remote" mode (i.e. the magnet exerts force on the cells without direct contact). Finally, we provide a perspective on the future directions and challenges in the development of MNPs for these two applications. By reviewing the examples of the design and applications of biofunctional MNPs, we hope that this article will provide a reference point for the future development of MNPs that address the present challenges and lead to new opportunities in nanomedicine and nanobiotechnology (137 references).
Carbon–carbon bond cleavage/functionalization is synthetically valuable, and selective carbonyl−C(sp3) bond cleavage/alkynylation presents a new perspective in constructing ynamides, ynoates, and ...ynones. Reported here is the first alkoxyl‐radical‐enabled carbonyl−C(sp3) bond cleavage/alkynylation reaction by photoredox catalysis. The use of novel cyclic iodine(III) reagents are essential for β‐carbonyl alkoxyl radical generation from β‐carbonyl alcohols, including alcohols with high redox potential (Epox
>2.2 V vs. SCE in MeCN). β‐Amide, β‐ester, and β‐ketone alcohols yield ynamides, ynoates, and ynones, respectively, for the first time, with excellent regio‐ and chemoselectivity under mild reaction conditions.
Aye, aye CIR: Novel cyclic iodine reagents (CIRs) are essential for β‐carbonyl alkoxyl radical generation from β‐carbonyl alcohols in carbonyl−C(sp3) bond cleavage/alkynylation reactions under photoredox catalysis. β‐Amide, β‐ester, and β‐ketone alcohols yield ynamides, ynoates, and ynones, respectively, with excellent regio‐ and chemoselectivity.
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► Product review valence and perceived helpfulness have a positive relationship. ► Product review length and perceived helpfulness have a positive relationship. ► All else the same, ...experiential reviews are less helpful than utilitarian reviews. ► The effects of review valence and length are moderated by product type. ► Reviewer innovativeness has an inverted-U-shaped effect on review helpfulness.
Online user-generated product reviews have become an indispensible tool for consumers and thus for retailers who want to attract and retain consumers. Yet, relatively little is known about what causes consumers to find an online peer review helpful to their shopping tasks. Prior research examines mostly the effects of product reviews on consumer product attitude, product choice, and product sales. This paper, however, provides an analysis of the determinants of review helpfulness. In two studies, we examine the effects of review characteristics, product type, and reviewer characteristics on perceived review helpfulness. With data collected from a real online retailer, we provide empirical evidence to support our conceptual predictions. Specifically, both review valence and length have positive effects on review helpfulness, but the product type (i.e., experiential vs. utilitarian product) moderates these effects. Using content analysis of reviews, we develop a measure of expressed reviewer innovativeness (i.e., the predisposition toward new products as revealed in review content). A curvilinear relationship exists between expressed reviewer innovativeness and review helpfulness. These findings lead to pertinent managerial implications.
The lignin-carbohydrate complex (LCC) was isolated from milled wood lignin of 2- and 24-month-old crude bamboo (
) culms using acetic acid (AcOH) and then characterized. The results have shown that ...the LCC preparation from 2-month-old bamboo (L₂) exhibited a slightly lower molecular weight than the LCC preparation from the 24-month-old bamboo (L
). Further studies using Fourier transform infrared spectroscopy (FT-IR) and heteronuclear single quantum coherence (2D-HSQC) NMR spectra analyses indicate that the LCC preparations included glucuronoarabinoxylan and G-S-H lignin-type with G>S>>H. The content of the S lignin units of LCC in the mature bamboo was always higher than in the young bamboo. Combined with sugar composition analysis, the contents of phenyl glycoside and ether linkages in the L
preparation were higher than in the L₂ preparation; however, there was a reverse relationship of ester LCC bonds in L₂ and L
. Lignin-xylan was the main type of LCC linkage in bamboo LCCs. Lignin-lignin linkages in the LCC preparations included β-β, β-5 and β-1 carbon-to-carbon, as well as β-
-4 ether linkages, but β-1 linkages were not present in L₂.
Fungi are key components of microbial communities in mangrove wetlands, with important roles in the transformation of nutrients and energy. However, existing studies typically focus on cultivable ...fungi and seldom on the structure and driving factors of entire fungal communities. The compositions, community assembly, and interaction patterns of mangrove fungal communities on a large scale remain elusive. Here, biogeography, assembly, and co-occurrence patterns of fungal communities in mangroves across eastern to southern China were systematically analyzed by targeting the entire internal transcribed spacer (ITS) region with high-throughput Pacific Biosciences single-molecule real-time sequencing. The analysis revealed a high level of fungal diversity, including a number of basal fungal lineages not previously reported in mangroves, such as
and
. Beta nearest-taxon index analyses suggested a determinant role of dispersal limitation on fungal community in overall and most individual mangroves, with support from the strong distance-decay patterns of community similarity. Further, nonmetric multidimensional scaling analyses revealed similar biogeographies of dominant and rare fungal communities. A minor role of environmental selection on the fungal community was noted, with geographical location and sediment depth as crucial factors driving the distribution of both, the dominant and rare taxa. Finally, network analysis revealed high modularized co-occurrence patterns of fungal community in mangrove sediments, and the keystone taxa might play important roles in microbial interactions and ecological functions. The investigation expands our understanding of biogeography, assembly patterns, driving factors, and co-occurrence relationships of mangrove fungi and will spur the further functional exploration and protection of fungal resources in mangroves.
As key components of microbial community in mangroves, fungi have important ecological functions. However, the fungal community in mangroves on a large scale is generally elusive, and mangroves are declining rapidly due to climate change and anthropogenic activities. This work provides an overview of fungal community structure and biogeography in mangrove wetlands along a >9,000-km coastline across eastern to southern China. Our study observed a high number of basal fungal lineages, such as
and
, in mangrove sediments. In addition, our results highlight a crucial role of dispersal limitation and a minor role of environmental selections on fungal communities in mangrove sediments. These novel findings add important knowledge about the structure, assembly processes, and driving factors of fungal communities in mangrove sediments.
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