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No full textAlteration of replication protein A binding mode on single-stranded DNA by NSMF potentiates RPA phosphorylation by ATR kinase
No full textReplication protein A (RPA), a eukaryotic single-stranded DNA (ssDNA) binding protein, dynamically interacts with ssDNA in different binding modes and plays essential roles in DNA metabolism such as replication, repair, and recombination. RPA accumulation on ssDNA due to replication stress triggers the DNA damage response (DDR) by activating the ataxia telangiectasia and RAD3-related (ATR) kinase, which phosphorylates itself and downstream DDR factors, including RPA. We recently reported that the N-methyl-D-aspartate receptor synaptonuclear signaling and neuronal migration factor (NSMF), a neuronal protein associated with Kallmann syndrome, promotes RPA32 phosphorylation via ATR upon replication stress. However, how NSMF enhances ATR-mediated RPA32 phosphorylation remains elusive. Here, we demonstrate that NSMF colocalizes and physically interacts with RPA at DNA damage sites in vivo and in vitro. Using purified RPA and NSMF in biochemical and single-molecule assays, we find that NSMF selectively displaces RPA in the more weakly bound 8- and 20-nucleotide binding modes from ssDNA, allowing the retention of more stable RPA molecules in the 30-nt binding mode. The 30-nt binding mode of RPA enhances RPA32 phosphorylation by ATR, and phosphorylated RPA becomes stabilized on ssDNA. Our findings provide new mechanistic insight into how NSMF facilitates the role of RPA in the ATR pathway
Mechanical and microstructural properties of lightweight CaO- activated fly ash composites in the presence of magnesium nitrate
No full textThe use of industrial by-products is required to replace cement to reduce carbon emission, and it is necessary to secure the strength of cementless binder to satisfy the required mechanical perfor-mance. The purpose of this study is to develop a new binder system composed of activated fly ash (FA) with CaO by adding magnesium nitrate ((Mg(NO3)2) as a new additive. To reveal the mecha-nism of strength enhancement, the influence of the dosage of Mg(NO3)2 on compressive strength, reaction products, and pore characteristics was observed. In addition, expanded perlite (EP) and expanded vermiculite (EV) were mixed in selected samples to develop a lightweight cementless composite. The results showed that adding Mg(NO3)2 significantly increased strength of CaO-activated FA system. In the reaction process, Mg(NO3)2 promoted the solubility of quicklime (CaO) to form more C-(A)-S-H and Ca-Mg-Al-(OH)-NO3-AFm phase and increased the initial con-centration of silicon (Si) and aluminum (Al) from FA. The dense C-(A)-S-H formation enhanced mechanical strength by reducing porosity in binder matrix. When EP and EV were mixed in the selected binder, even if the strength decreased as the amount of EP and EV increased, the require-ments for the strength and specific gravity of commercial autoclave aerated concrete (AAC) were satisfied
The Supremacy of IBE over Bayesian Conditionalization
No full textVan Fraassen does not merely perform Bayesian conditionalization on his pragmatic theory of scientific explanation; he uses inference to the best explanation (IBE) to justify it, contrary to what Prasetya thinks. Without first using IBE, we cannot carry out Bayesian conditionalization, contrary to what van Fraassen thinks. The argument from a bad lot, which van Fraassen constructs to criticize IBE, backfires on both the pragmatic theory and Bayesian conditionalization, pace van Fraassen and Prasetya
Metasurface spatial filters for multiple harmonic signals
No full textNonlinear frequency mixings have shown an alternative way to create new electromagnetic sources in frequency ranges that are difficult to access with conventional techniques. To simultaneously use the fundamental frequency pump beam and multiple harmonic signals generated in the same channel, a device capable of separating each frequency component is required. Here, we propose and experimentally demonstrate metasurface-based spatial filters for the pump frequency and multiple harmonic frequencies. The metasurface was designed using eight different split ring resonator-based phase elements with 45 degrees phase spacing, which allows wavefront shaping. The metasurface designed to have a one-dimensional gradient phase array produces cross-polarized reflection waves with different beam steering angles at the third- and fifth-harmonic frequencies (15 and 25 GHz) and operates as a metallic mirror at the fundamental frequency of 5 GHz. Our work suggests a new method to enable simultaneous use of broadband multi-frequency sources based on nonlinear frequency mixing
Ultralow-k Amorphous Boron Nitride Film for Copper Interconnect Capping Layer
No full textWe report the feasibility of ultralow-k amorphous boron nitride (alpha-BN) film as a new capping layer for copper (Cu) interconnects. alpha-BN thin films were successfully deposited using a plasma-enhanced chemical vapor deposition (PECVD) process. The CVD-grown alpha-BN showed a k-value as low as 2.0 at 3 nm thickness, low leakage current density (similar to 7 x 10(-8) A/cm(2)), and high breakdown field (similar to 8.8 MV/cm) comparable to a conventional SiN blocking layer. The alpha-BN has excellent thermal stability up to 1000 degrees C, implying that the film can be used not only for the back-end-of-line (BEOL) but also for the front-end-of line (FEOL) processes. A 7-nm-thick alpha-BN film successfully blocked Cu diffusion at temperatures up to 500 degrees C. The alpha-BN film also showed excellent adhesion to Cu, with an adhesion energy of 2.90 +/- 0.51 J/m(2) between alpha-BN and Cu. The COMSOL multiphysics simulation predicted that, compared to a conventional SiN capping layer, an alpha-BN capping layer would reduce interconnect RC delay by up to 17%. The alpha-BN was proven to be a promising new candidate for a capping layer to reduce RC delay in Cu interconnect systems
Polar Perturbations in Functional Oxide Heterostructures
No full textGrowth and characterization of metal-oxide thin films foster successful development of oxide-material-integrated thin-film devices represented by metal-oxide-semiconductor field-effect transistors (MOSFET), drawing enormous technological and scientific interest for several decades. In recent years, functional oxide heterostructures have demonstrated remarkable achievements in modern technologies and provided deeper insights into condensed-matter physics and materials science owing to their versatile tunability and selective amplification of the functionalities. One of the most critical aspects of their physical properties is the polar perturbation stemming from the ionic framework of an oxide. By engineering and exploiting the structural, electrical, magnetic, and optical characteristics through various routes, numerous perceptive studies have clearly shown how polar perturbations advance functionalities or drive exotic physical phenomena in complex oxide heterostructures. In this review, both intrinsic (engraved by thin-film heteroepitaxy) and extrinsic (reversibly controllable defect-mediated disorder and polar adsorbates) elements of polar perturbations, highlighting their abilities for the development of highly tunable functional properties are summarized. Scientifically, the recent approaches of polar perturbations render one to consolidate a prospect of atomic-level manipulation of polar order in epitaxial oxide thin films. Technologically, this review also offers useful guidelines for rational design to heterogeneously integrated oxide-based multi-functional devices with high performances
Downskin Surface Roughness Prediction with Machine Learning for As-Built CM247LC Fabricated Via Powder Bed Fusion with a Laser Beam
No full textPowder bed fusion with a laser beam (PBF-LB) is a widely used metal additive manufacturing method for fabricating complex three-dimensional components with a variety of metallic powders. However, metal parts fabricated by PBF-LB often present surface quality problems because of the layer-wise building process and the occurrence of partially unmelted powder particles. To reduce the surface roughness, surface post-processing is required, which incurs additional time and cost. In particular, the downskin surface generally has the worst surface roughness among the fabricated components. The rough surface reduces the lifetime and quality of the holed part owing to cracks, corrosion, and wear. In this study, for fast and efficient improvement of the downskin surface roughness of CM247LC fabricated by PBF-LB, machine learning algorithms, namely support vector regression (SVR), random forest (RF), and multilayer perceptron (MLP), were introduced to predict downskin surface roughness in the process parameter selection step. Three PBF-LB process parameters (laser power, scanning speed, and hatching distance) and the overhang angle were selected as the input variables for the machine learning models for predicting downskin surface roughness. Test samples were prepared and used for training and evaluation of the proposed machine learning algorithms, with RF showing the most promising results. Early results were confirmed when model predictions were compared to the actual measured roughness of a fabricated vane part, with average deviations of 13.7%, 4.3%, and 22.5% observed for SVR, RF, and MLP, respectively. The results showed that the proposed machine learning models could accurately predict the downskin surface roughness in the process parameter selection step without the use of any sensor, with RF showing the highest prediction accuracy
Detecting ??-Radiation Using a Plastic Scintillator Containing 2,5-Diphenyloxazole-Functionalized Conjugated Polyfluorene
No full textPlastic scintillators, as a type of radioactive radiation detectors, have shown great potential in the field of nuclear radiation detection because of their well-studied scintillating property. Although much effort has been dedicated to developing plastic scintillators with high detection efficiency, materials with excellent monitoring performance are still needed. A covalent-integration strategy was implemented in the fabrication of a series of polyvinyltoluene (PVT) scintillators containing a polyfluorene-based conjugated polymer (CP) for the detection of radioactive nuclides of Sr-90 and C-14; the scintillators feature an excellent cascade energy transfer from beta radiation to the CP. To act as an antenna for beta-radiation harvesting, the fluorescent dopant 2,5diphenyloxazole (PPO) was covalently introduced to the CP side chain. The PPO-functionalized CP was embedded in PVT to fabricate the polymer-blend scintillator, showing enhanced photomultiplier-detectable signal via efficient energy transfer. The cascade energy transfer, in which the beta-radiation energy was absorbed by PVT and PPO and was finally transferred to CP, was successfully demonstrated. The scintillator showed a high detection efficiency of up to 50% under Sr-90 radiation, i.e., 30% higher efficiency than a PVT-containing simple mixture of CP and PPO, and it was also better than a conventional scintillator that contained PVT and PPO
Macroeconomic Conditions and Wage Inequality: Expanding and Analyzing the Worldwide Dataset
No full textThis paper introduces a comprehensive dataset examining wage inequality and returns to education across 40 countries, revisiting earlier studies on the effects of economic development, trade openness, and returns to skill on wage inequality. Our findings include: (i) the presence of Kuznets' "inverted U-curve" in wage inequality data, (ii) a positive relationship between trade openness and both wage inequality and returns to education, (iii) a positive relationship between levels of wage inequality and levels of return to education, and (iv) an intriguing phenomenon where accelerated skill-biased technological change leads to a deceleration of the wage gap widening process, as evidenced by the negative relationship between changes in wage inequality and changes in returns to education