Pusan National University

About: Pusan National University is a education organization based out in Busan, South Korea. It is known for research contribution in the topics: Catalysis & Population. The organization has 24124 authors who have published 45054 publications receiving 819356 citations. The organization is also known as: Busan National University & Pusan University.

Selective Frontoinsular von Economo Neuron and Fork Cell Loss in Early Behavioral Variant Frontotemporal Dementia

Abstract: Behavioral variant frontotemporal dementia (bvFTD) erodes complex social–emotional functions as the anterior cingulate cortex (ACC) and frontoinsula (FI) degenerate, but the early vulnerable neuron within these regions has remained uncertain. Previously, we demonstrated selective loss of ACC von Economo neurons (VENs) in bvFTD. Unlike ACC, FI contains a second conspicuous layer 5 neuronal morphotype, the fork cell, which has not been previously examined. Here, we investigated the selectivity, disease-specificity, laterality, timing, and symptom relevance of frontoinsular VEN and fork cell loss in bvFTD. Blinded, unbiased, systematic sampling was used to quantify bilateral FI VENs, fork cells, and neighboring neurons in 7 neurologically unaffected controls (NC), 5 patients with Alzheimer's disease (AD), and 9 patients with bvFTD, including 3 who died of comorbid motor neuron disease during very mild bvFTD. bvFTD showed selective FI VEN and fork cell loss compared with NC and AD, whereas in AD no significant VEN or fork cell loss was detected. Although VEN and fork cell losses in bvFTD were often asymmetric, no group-level hemispheric laterality effects were identified. Right-sided VEN and fork cell losses, however, correlated with each other and with anatomical, functional, and behavioral severity. This work identifies region-specific neuronal targets in early bvFTD.

High-Efficiency Isolated Bidirectional AC–DC Converter for a DC Distribution System

Abstract: A high-efficiency isolated bidirectional ac–dc converter is proposed for a 380-V dc power distribution system to control bidirectional power flows and to improve its power conversion efficiency. To reduce the switches’ losses of the proposed nonisolated full-bridge ac–dc rectifier using an unipolar switching method, switching devices employ insulated-gate bipolar transistors, MOSFETs, and silicon carbide diodes. Using the analysis of the rectifier’s operating modes, each switching device can be selected by considering switch stresses. A simple and intuitive frequency detection method for a single-phase synchronous reference frame-phase-locked loop (SRF-PLL) is also proposed using a filter compensator, a fast period detector, and a finite impulse response filter to improve the robustness and accuracy of PLL performance under fundamental frequency variations. In addition, design and control methodology of the bidirectional full-bridge CLLC resonant converter is suggested for the galvanic isolation of the dc distribution system. A dead-band control algorithm for the bidirectional dc–dc converter is developed to smoothly change power conversion directions only using output voltage information. Experimental results will verify the performance of the proposed methods using a 5-kW prototype converter.

Waterborne polyurethanes and their properties

Abstract: Anionomer-type waterborne polyurethanes (PUs) were obtained from poly(β-methyl-δ-valerolactone) glycol (PMVL) and isophorone diisocyanate, following a prepolymer mixing process. The soft-hard segment phase separation in response to the variations of composition and structure of PU has been studied from the dynamic mechanical measurements of the emulsion cast films. The structural variation included ionic and hard segment content, molecular weight of NCO-terminated prepolymer, and type and length of the soft segment. It was found that phase separation is more sensitive to the soft segment length, rather than the soft segment content. With only phase separation, the rubbery modulus was significant even with lower hard segment content. Phase separation was much more pronounced with PU from poly(tetramethylene adipate) glycol, rather than from PMVL and poly(caprolactone) © 1996 John Wiley & Sons, Inc.

A gravitational-wave measurement of the Hubble constant following the second observing run of Advanced LIGO and Virgo

Abstract: This paper presents the gravitational-wave measurement of the Hubble constant (H 0) using the detections from the first and second observing runs of the Advanced LIGO and Virgo detector network. The presence of the transient electromagnetic counterpart of the binary neutron star GW170817 led to the first standard-siren measurement of H 0. Here we additionally use binary black hole detections in conjunction with galaxy catalogs and report a joint measurement. Our updated measurement is H 0 = km s−1 Mpc−1 (68.3% of the highest density posterior interval with a flat-in-log prior) which is an improvement by a factor of 1.04 (about 4%) over the GW170817-only value of km s−1 Mpc−1. A significant additional contribution currently comes from GW170814, a loud and well-localized detection from a part of the sky thoroughly covered by the Dark Energy Survey. With numerous detections anticipated over the upcoming years, an exhaustive understanding of other systematic effects are also going to become increasingly important. These results establish the path to cosmology using gravitational-wave observations with and without transient electromagnetic counterparts.