Abstract
The regioselectivity of C−H functionalization is commonly achieved by directing groups, electronic factors, or steric hindrance, which facilitate the identification of reaction sites. ...However, such strategies are less effective for reactants such as simple monofluoroarenes due to their relatively low reactivity and the modest steric demands of the fluorine atom. Herein, we present an undirected gold‐catalyzed
para
‐C−H arylation of a wide array of monofluoroarenes using air‐stable aryl silanes and germanes at room temperature. A high
para
‐regioselectivity (up to 98 : 2) can be realized by utilizing a dinuclear dppm(AuOTs)
2
(dppm=bis(diphenylphosphino)methane) as the catalyst and hexafluorobenzene as the solvent. This provides a general and practical protocol for the concise construction of structurally diverse
para
‐arylated monofluoroarenes through C−H activation manner. It features excellent functional group tolerance and a broad substrate scope (>80 examples). Besides, this strategy is also robust for other simple monosubstituted arenes and heteroarenes. Our mechanistic studies and theoretical calculations suggest that
para
‐C−H selectivity arises from highly electrophilic and structurally flexible dinuclear Ar−Au(III)−Au(I) species, coupled with noncovalent interaction induced by hexafluorobenzene.
Reflection fiber temperature sensors functionalized with plasmonic nanocomposite material using intensity-based modulation are demonstrated for the first time. Characteristic temperature optical ...response of the reflective fiber sensor is experimentally tested using Au-incorporated nanocomposite thin films deposited on the fiber tip, and theoretically validated using a thin-film-optic-based optical waveguide model. By optimizing the Au concentration in a dielectric matrix, Au nanoparticles (NP) exhibit a localized surface plasmon resonance (LSPR) absorption band in a visible wavelength that shows a temperature sensitivity ~0.025%/°C as a result of electron-electron and electron-phonon scattering of Au NP and the surrounding matrix. Detailed optical material properties of the on-fiber sensor film are characterized using scanning electron microscopy (SEM) and focused-ion beam (FIB)-assisted transmission electron microscopy (TEM). Airy's expression of transmission and reflection using complex optical constants of layered media is used to model the reflective optical waveguide. A low-cost wireless interrogator based on a photodiode transimpedance-amplifier (TIA) circuit with a low-pass filter is designed to integrate with the sensor. The converted analog voltage is wirelessly transmitted via 2.4 GHz Serial Peripheral Interface (SPI) protocols. Feasibility is demonstrated for portable, remotely interrogated next-generation fiber optic temperature sensors with future capability for monitoring additional parameters of interest.
Applications of fiber optic sensors to battery monitoring have been increasing due to the growing need of enhanced battery management systems with accurate state estimations. The goal of this review ...is to discuss the advancements enabling the practical implementation of battery internal parameter measurements including local temperature, strain, pressure, and refractive index for general operation, as well as the external measurements such as temperature gradients and vent gas sensing for thermal runaway imminent detection. A reasonable matching is discussed between fiber optic sensors of different range capabilities with battery systems of three levels of scales, namely electric vehicle and heavy-duty electric truck battery packs, and grid-scale battery systems. The advantages of fiber optic sensors over electrical sensors are discussed, while electrochemical stability issues of fiber-implanted batteries are critically assessed. This review also includes the estimated sensing system costs for typical fiber optic sensors and identifies the high interrogation cost as one of the limitations in their practical deployment into batteries. Finally, future perspectives are considered in the implementation of fiber optics into high-value battery applications such as grid-scale energy storage fault detection and prediction systems.
Lipopolysaccharide (LPS) is widely used to establish various animal models, including models of acute lung injury, cardiomyocyte damage, and acute kidney injury. Currently, there is no consensus on ...the diagnosis and treatment of LPS-induced disease. We herein present a case series of four patients who developed dose-dependent multi-organ injury, including acute lung injury and acute kidney injury, after inhaling LPS gas in a sealed room. These patients exhibited varying degrees of multi-organ injury characterized by inflammatory cell infiltration and secretion of proinflammatory cytokines. One patient showed progressive symptoms even with active treatment, leading to mild pulmonary fibrosis. This study emphasizes the importance of early diagnosis and treatment of significant LPS exposure and suggests personalized treatment approaches for managing LPS poisoning.
With the wide and deep application of computer technologies in the field of metal cutting, many manufacturing enterprises have accumulated a large volume of data including workpieces, cutting tools, ...machine tools, processes, and materials. These data are very valuable resources for enterprises. In this paper, a novel tool selection approach is proposed to deeply mine the relationships hidden in these data. First, an ontology model of the metal cutting process is established with OWL (Web Ontology Language), and a metal cutting process knowledge graph (MCPKG) is constructed based on the ontology model. Then, a data model describing the relationship “structural feature-material-cutting tool” is designed to build a subgraph based on the MCPKG. Moreover, the personalized PageRank (PPR) algorithm is employed with the data model to recommend cutting tools for process planning, and the result of an illustrative example is discussed in detail to verify the algorithm. Finally, a cutting tool selection system with B/S (browser/server) structure based on .NET MVC (model view control) is developed. To recommend cutting tools, the presented approach utilizes the connectivity of the MCPKG to score and rank the usage effect of each tool, which is universally applicable to manufacturing enterprises and provides valuable insights into intelligent cutting tool selection.
Spinal cord microcirculation plays an important role in maintaining the function of spinal cord neurons and other cells. Previous studies have largely focused on the ability of microtubule ...stabilization to inhibit the fibroblast migration and promote axon regeneration after spinal cord injury (SCI). However, the effect of microtubule stabilization treatment on microcirculation reconstruction after SCI remains unclear. By using immunofluorescence, we found that microtubule stabilization treatment improved microcirculation reconstruction via increasing the number of microvessels, pericytes, and the perfused microvessels after SCI. To clarify the underlying mechanisms, rat brain microvascular endothelial cells and pericytes were subjected to glucose oxygen deprivation. By using flow cytometry and western blotting, we found that microtubule stabilization treatment inhibited apoptosis and migration of endothelial cells and pericytes but promoted proliferation and survival of endothelial cells and pericytes through upregulated expression of vascular endothelial growth factor A (VEGFA), VEGF receptor 2, platelet-derived growth factor-B (PDGFB), PDGF receptor β, and angiopoietin-1 after SCI. Taken together, this study provides evidence for the mechanisms underlying the promotion of microcirculation reconstruction after SCI by microtubule stabilization treatment. Importantly, this study suggests the potential of microtubule stabilization as a therapeutic target to reduce microcirculation dysfunction after SCI in the clinic.
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