Large-scale, highly integrated and low-power-consuming hardware is becoming progressively more important for realizing optical neural networks (ONNs) capable of advanced optical computing. ...Traditional experimental implementations need N
units such as Mach-Zehnder interferometers (MZIs) for an input dimension N to realize typical computing operations (convolutions and matrix multiplication), resulting in limited scalability and consuming excessive power. Here, we propose the integrated diffractive optical network for implementing parallel Fourier transforms, convolution operations and application-specific optical computing using two ultracompact diffractive cells (Fourier transform operation) and only N MZIs. The footprint and energy consumption scales linearly with the input data dimension, instead of the quadratic scaling in the traditional ONN framework. A ~10-fold reduction in both footprint and energy consumption, as well as equal high accuracy with previous MZI-based ONNs was experimentally achieved for computations performed on the MNIST and Fashion-MNIST datasets. The integrated diffractive optical network (IDNN) chip demonstrates a promising avenue towards scalable and low-power-consumption optical computational chips for optical-artificial-intelligence.
We examine how chief executive officer (CEO) narcissism influences the inter-organizational imitation of corporate strategy. We theorize that narcissistic CEOs are influenced more by the corporate ...strategies they experienced on other boards and less by the corporate strategies experienced by other directors. These effects are strengthened if the other firms to which the CEO has interlock ties have high status and if the CEO is powerful. Through longitudinal analyses of Fortune 500 companies' decisions (from 1997 to 2006) related to the acquisition emphasis of a firm's growth strategy and the firm's level of international diversification, we show that narcissistic CEOs are influenced by corporate strategies that they witnessed at other firms much more than other CEOs. In addition, relatively narcissistic CEOs not only strongly resist the influence of other directors' prior experience but also tend to demonstrate their superiority by adopting corporate strategies that are the opposite of what fellow directors' prior experience would suggest. Our theory and results highlight how CEO narcissism limits directors' influence over corporate strategy and influences CEOs' learning and information processing in making strategic decisions.
Magnetic cellulose/Fe₃O₄/activated carbon composites (m-Cell/Fe₃O₄/ACCs) were prepared successfully and characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), thermogravimetric ...analysis (TGA), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). The adsorption of congo red onto the novel m-Cell/Fe₃O₄/ACCs was studied as a function of contact time, initial concentration of congo red, adsorbent dosage, and pH of solution. The saturated magnetization of m-Cell/Fe₃O₄/ACCs reached 48.2emug⁻¹ and the magnetic adsorbent showed characteristics of superparamagnetism, which indicated that m-Cell/Fe₃O₄/ACCs could be separated from treated solution by a magnetic process. A comparison of kinetic models showed that the overall adsorption process was best described by pseudo-second-order kinetic model. Thermodynamic analysis indicated an exothermic nature of adsorption and a spontaneous and favorable process. The m-Cell/Fe₃O₄/ACCs might be a promising candidate of high efficiency, low cost and convenient separation under magnetic field.
In this paper, studies on dynamic modeling, simulation and experiment of power transmission belt drives are comprehensively reviewed. In the past few decades, many investigations are conducted on ...dynamic modeling, simulation and experiment of different kinds of power transmission belt drive systems. In the dynamic modeling and simulation of the belt drive systems, surveys are focused on vibrations of a single axially moving belt span, rotational vibrations of pulley components, coupled belt-pulley vibrations and contact mechanics between the belt and pulley as well as some experimental investigations. Influences of tensioner dry friction and one-way clutch on dynamics of the belt drive systems including system rotational vibrations and coupled belt-pulley vibrations are separately reported. The investigations are also surveyed on modeling and predicting complicated belt-pulley contact behaviors like belt creeps and slips on pulleys, contact force distributions of the belt and pulley, and variation of wrap angles of a belt around pulleys, etc., which are categorized by different approaches including the creep theory, shear theory, multi-body dynamics and finite element methods. Fatigue life estimation and failure analysis of power transmission belt drives are discussed in detail as well. In addition, experimental techniques are reviewed on parameters identifications, and measurements of static and dynamic performances including energy/power loss, system vibration, dynamic belt tension, belt deformation, stress and strain distribution in the belt and pulley, and contact friction force, etc. Finally, conclusion of this work is summarized and topics of future potential studies on the power transmission belt drive systems are suggested.
We explain why CEOs favor new directors who are similar in narcissistic tendency or have prior experience with other similarly narcissistic CEOs. Because powerful CEOs are more able to select such ...individuals onto their boards, CEO power is predicted to be positively associated with the above characteristics of new directors. These associations are expected to be stronger when a new director is more different from the CEO in salient demographic characteristics. Moreover, we explain why new directors favored by CEOs are more supportive of their decision making, strengthening the positive relationship between CEO narcissism and risk-taking spending. Our findings provide considerable support for our theory. This study introduces personality theories to corporate governance research on director selection and to research on how triads influence dyadic relations.
This study investigates how a fundamental group decision-making bias referred to as group polarization can influence boards' acquisition premium decisions. The theory suggests that when prior premium ...experience would lead directors on average to support a relatively high premium prior to board discussions, they will support a focal premium that is even higher after discussions; but when directors' prior premium experience would lead them on average to support a relatively low premium prior to board discussions, they will support a focal premium that is even lower after discussions. Results provided strong support for the theory. Moreover, group polarization was reduced by demographic homogeneity among directors and by minority expertise but increased by board influence. This study introduces a fundamental group decision-making bias into governance research and explains how group processes can influence network diffusions.
The TET (ten-eleven translocation) family of α-ketoglutarate (α-KG)-dependent dioxygenases catalyzes the sequential oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), ...5-formylcytosine and 5-carboxylcytosine, leading to eventual DNA demethylation. The TET2 gene is a bona fide tumor suppressor frequently mutated in leukemia, and TET enzyme activity is inhibited in IDH1/2-mutated tumors by the oncometabolite 2-hydroxyglutarate, an antagonist of α-KG, linking 5mC oxidation to cancer development. We report here that the levels of 5hmC are dramatically reduced in human breast, liver, lung, pancreatic and prostate cancers when compared with the matched surrounding normal tissues. Associated with the 5hmC decrease is the substantial reduction of the expression of all three TET genes, revealing a possible mechanism for the reduced 5hmC in cancer cells. The decrease of 5hmC was also observed during tumor development in different genetically engineered mouse models. Together, our results identify 5hmC as a biomarker whose decrease is broadly and tightly associated with tumor development.
Cancer associated fibroblasts (CAFs) are key stroma cells that play dominant roles in tumor progression. However, the CAFs-derived molecular determinants that regulate colorectal cancer (CRC) ...metastasis and chemoresistance have not been fully characterized.
CAFs and NFs were obtained from fresh CRC and adjacent normal tissues. Exosomes were isolated from conditioned medium and serum of CRC patients using ultracentrifugation method and ExoQuick Exosome Precipitation Solution kit, and characterized by transmission electronic microscopy, nanosight and western blot. MicroRNA microarray was employed to identify differentially expressed miRNAs in exosomes secreted by CAFs or NFs. The internalization of exosomes, transfer of miR-92a-3p was observed by immunofluorescence. Boyden chamber migration and invasion, cell counting kit-8, flow cytometry, plate colony formation, sphere formation assays, tail vein injection and primary colon cancer liver metastasis assays were employed to explore the effect of NFs, CAFs and exosomes secreted by them on epithelial-mesenchymal transition, stemness, metastasis and chemotherapy resistance of CRC. Luciferase report assay, real-time qPCR, western blot, immunofluorescence, and immunohistochemistry staining were employed to explore the regulation of CRC metastasis and chemotherapy resistance by miR-92a-3p, FBXW7 and MOAP1.
CAFs promote the stemness, epithelial-mesenchymal transition (EMT), metastasis and chemotherapy resistance of CRC cells. Importantly, CAFs exert their roles by directly transferring exosomes to CRC cells, leading to a significant increase of miR-92a-3p level in CRC cells. Mechanically, increased expression of miR-92a-3p activates Wnt/β-catenin pathway and inhibits mitochondrial apoptosis by directly inhibiting FBXW7 and MOAP1, contributing to cell stemness, EMT, metastasis and 5-FU/L-OHP resistance in CRC. Clinically, miR-92a-3p expression is significantly increased in CRC tissues and negatively correlated with the levels of FBXW7 and MOAP1 in CRC specimens, and high expression of exosomal miR-92a-3p in serum was highly linked with metastasis and chemotherapy resistance in CRC patients.
CAFs secreted exosomes promote metastasis and chemotherapy resistance of CRC. Inhibiting exosomal miR-92a-3p provides an alternative modality for the prediction and treatment of metastasis and chemotherapy resistance in CRC.
A metasurface (MS) used to convert the linearly polarized (LP) signal from a source antenna into a circularly polarized (CP) signal is proposed and studied. The MS consists of 16 unit cells arranged ...in a 4 × 4 layout. Each unit cell is a rectangular loop with a diagonal microstrip. By placing close to a source antenna, the MS converts the LP signal generated from the source antenna into a CP signal. Two source antennas (patch and slot antennas) are used for studies. The source antenna together with the MS is here called a MS antenna. A total of four low-profile MS antennas operating at the frequency of about 2.45 GHz are designed using computer simulation. For verification of simulation results, the MS antennas are fabricated and measured. Simulated and measured results show good agreements. Results show that the MS antennas have substantially better performances, in terms of gain, return-loss bandwidth (RLBW), axial-ratio bandwidth (ARBW) and radiation pattern, than the source antennas. Moreover, the ARBW of the MS antennas is mainly determined by the MS.
A novel magnetic composite bioadsorbent composed of chitosan wrapping magnetic nanosized γ-Fe₂O₃ and multi-walled carbon nanotubes (m-CS/γ-Fe₂O₃/MWCNTs) was prepared under relative mild conditions ...and was characterized. Adsorption of methyl orange (MO) onto m-CS/γ-Fe₂O₃/MWCNTs was investigated with respect to pH, initial MO concentration, coexisting anions and temperature. Results of characterizations indicated that magnetic nanosized γ-Fe₂O₃ and MWCNTs have been wrapped by crosslinked chitosan. Introduction of MWCNTs could obviously increase the adsorption capacity (qe ) of MO onto bioadsorbent by 2.2 times. Kinetics data and adsorption isotherm were better fitted by pseudo-second-order kinetic model and by Langmuir isotherm, respectively. Values of activation parameters such as free energy (△G°), enthalpy (△H°) and entropy (ΔS°) were determined as 3.15-3.78kJmol⁻¹, −9.94kJmol⁻¹ and −20.65Jmol⁻¹ k⁻¹, respectively, indicating that the adsorption was feasible, spontaneous and exothermic process in nature. After adsorption, m-CS/γ-Fe₂O₃/MWCNTs could be effectively and fleetly separated by applying a magnetic field.
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