bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of main chain polymeric benzophenone photoinitiator via thiol‐ene click chemistry and Its use in free radical polymerization
Authors: Temel Gokhan , Karaca Nurcan , Arsu Nergis 
Published: October 2010

AbstractMain chain polymeric benzophenone photoinitiator (PBP) was synthesized by using “Thiol‐ene Click Chemistry” and characterized with 1H NMR, FTIR, UV, and phosphorescence spectroscopies. PBP as a polymeric photoinitiator presented excellent absorption properties (ε294 = 28,300 mol−1L−1cm−1) compared to the molecular initiator BP (ε252 = 16,600 mol−1L−1cm−1). The triplet energy of PBP was obtained from the phosphorescence measurement in 2‐methyl tetrahydrofurane at 77 K as 298.3 kJ/mol and according to phosphorescence lifetime, the lowest triplet state of PBP has an n‐π* nature. Triplet–triplet absorption spectrum of PBP at 550 nm following laser excitation (355 nm) were recorded and triplet lifetime of PBP was found as 250 ns. The photoinitiation efficiency of PBP was determined for the polymerization of Hexanedioldiacrylate (HDDA) with PBP and BP in the presence of a coinitiator namely, N‐methyldiethanolamine (MDEA) by Photo‐DSC. The initiation efficiency of PBP for polymerization of HDDA is much higher than for the formulation consisting of BP. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Synthesis of amphiphilic block copolymers bearing stable nitroxyl radicals
Authors: Zhuang Xiuli , Xiao Chunsheng , Oyaizu Kenichi , Chikushi Natsuru , Chen Xuesi , Nishide Hiroyuki 
Published: October 2010

AbstractWe present here the synthesis of two kinds of amphiphilic block copolymers, a diblock copolymer MPEG‐b‐PTAm and a triblock copolymer MPEG‐b‐PLA‐b‐PTAm, which can self‐assemble into micelles with nitroxyl radicals‐containing PTAm segment in the core. The structure of the block copolymers was characterized by 1H NMR and GPC. Dynamic laser light scattering and transmission electron microscopy were used to study the micellar behavior of the two block copolymers in aqueous solution. The micelles carrying nitroxyl radicals in the core can generate electron paramagnetic resonance, which is stable for a period of time up to 8 min even in the presence of reducing reagent such as ascorbic acid. The enhanced stability against the reducing agent was ascribed to the inaccessibility of the nitroxyl radical core placed in the interior of the micelles. Combined with the biocompatibility, these micelles were promising to be used as the EPR probes for bioimaging in vivo. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Synthesis and nonlinear optical properties of polyacetylenes containing oxadiazole and thiophene pendant groups with high thermal stability
Authors: Wang Xin , Yan Yongxin , Liu Tianbao , Su Xinyan , Qian Liwu , Song Yinglin , Xu Hongyao 
Published: October 2010

AbstractA series of random copolymers poly(3‐ethynylthiophene)‐copoly(2‐(4‐decyloxyphenyl)‐5‐(4‐ethynylphenyl)‐1,3,4‐oxadiazole) with different oxadiazole content (P2–P4) and homopolymer poly(3‐ethynylthiophene) (P1) as well as poly(2‐(4‐decyloxyphenyl)‐5‐(4‐ethynylphenyl)‐1,3,4‐oxadiazole) (P5) were prepared. The copolymers (P2–P4) are completely soluble in common organic solvents. The structures and properties of all polymers were characterized and evaluated by FTIR, 1H NMR, 13C NMR, TGA, UV, PL, GPC, and nonlinear optical (NLO) analyses. The incorporation of diaryl‐oxadiazole into polyacetylene‐containing thiophene significantly endows copolymers with higher thermal stability, which may origin from the synergetic effect of the “jacket effect” of diaryl‐oxadiazole units and the effect of retarding or eliminating a few 6π‐electrocycliaztion proceeds of oxadiazole‐containing polyacetylene due to the hindrance of thiophene units. When the copolymer (P3) posses more regular alternating thiophene pendants and oxadiazole pendants arrangement along the polymer backbone, it shows good thermal stability (Td up to 388 °C) and larger third‐order nonlinear optical susceptibility (χ(3) up to 11.0 × 10−11 esu). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Novel superhydrophobic silica/poly(siloxane‐fluoroacrylate) hybrid nanoparticles prepared via two‐step surface‐initiated ATRP: Synthesis, characterization, and wettability
Authors: Yu Hai‐Jiang , Luo Zheng‐Hong 
Published: October 2010

AbstractPoly(siloxane‐fluoroacrylate)‐grafted silica hybrid nanoparticles were prepared by surface‐initiated atom transfer radical polymerization (SI‐ATRP). The silica nanoparticles with α‐bromo‐ester initiator group for copper‐mediated ATRP were prepared by the self‐assembled monolayers of (3‐aminopropyl)triethoxysilane and 2‐bromoisobutyrate bromide. Well‐defined diblock copolymer brushes consisting of poly(methacryloxypropyltrimethoxysilane) and poly(2,2,3,3,4,4,4‐heptafluorobutyl methacrylate) blocks were obtained by using initial homopolymer brushes as the macroinitiators for the SI‐ATRP of the second monomer. Chemical compositions and structures of the nanoparticles were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and gel permeation chromatography. Surface properties and morphology of the nanoparticles were investigated with X‐ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy, and water contact angle measurement. It is revealed that the surfaces of the nanocomposites are rough at the microscale and nanoscale. The formation reason of the superhydrophobic surfaces was also discussed in this work. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Behavior of the ATP grasp domain of biotin carboxylase monomers and dimers studied using molecular dynamics simulations
Authors: Novak Brian R. , Moldovan Dorel , Waldrop Grover L. , de Queiroz Marcio S. 
Published: October 2010

AbstractThe enzyme biotin carboxylase (BC) uses adenosine triphosphate (ATP) to carboxylate biotin and is involved in fatty acid synthesis. Structural evidence suggests that the B domain of BC undergoes a large hinge motion of ∼45° when binding and releasing substrates. Escherichia coli BC can function as a natural homodimer and as a mutant monomer. Using molecular dynamics simulations, we evaluate the free energy profile along a closure angle of the B domain of E. coli BC for three cases: a monomer without bound Mg2ATP, a monomer with bound Mg2ATP, and a homodimer with bound Mg2ATP in one subunit. The simulation results show that a closed state is the most probable for the monomer with or without bound Mg2ATP. For the dimer with Mg2ATP in one of its subunits, communication between the two subunits was observed. Specifically, in the dimer, the opening of the subunit without Mg2ATP caused the other subunit to open, and hysteresis was observed upon reclosing it. The most stable state of the dimer is one in which the B domain of both subunits is closed; however, the open state for the B domain without Mg2ATP is only approximately 2kBT higher in free energy than the closed state. A simple diffusion model indicates that the mean times for opening and closing of the B domain in the monomer with and without Mg2ATP are much smaller than the overall reaction time, which is on the order of seconds. Proteins 2011. © 2010 Wiley‐Liss, Inc.
A Bayesian optimal design for accelerated degradation tests
Authors: Liu Xiao , Tang Loon‐Ching 
Published: October 2010

AbstractThis paper proposes a Bayesian design approach to planning a pre‐production accelerated design test (ADT) with physically based statistical models. To motivate the study, we consider the hot‐carrier‐induced degradation of modern MOS field effect transistors. A single‐path power‐law statistical degradation model with nonlinear stress–life relationships is first developed. Based on this model, we formulate a Bayesian optimal design problem that minimizes the expected pre‐posterior variance of the quantity of interest at use environment. To solve the problem, a simulation‐based stochastic optimization method, which yields a consistent estimate of the optimal design, is utilized. As demonstrated by the numerical example, such an algorithm is of great practical importance in planning an ADT because it is considerably faster than the commonly used Monte Carlo simulation for evaluating the expected pre‐posterior variance. Finally, we perform a comparison study between the proposed Bayesian plan and the locally optimal plan, which is based on the maximum likelihood theory. Results strongly suggest that the robustness of the proposed plan against the uncertainty associated with planning inputs can be significantly enhanced. Copyright © 2010 John Wiley & Sons, Ltd.
Double‐Peak Mechanical Properties of Carbon‐Nanotube Fibers
Authors: Zhao Jingna , Zhang Xiaohua , Di Jiangtao , Xu Geng , Yang Xiaojie , Liu Xiangyang , Yong Zhenzhong , Chen Minghai , Li Qingwen 
Published: October 2010

AbstractThe introduction of twist during the spinning of carbon nanotubes from their arrays (forests) has been widely applied in making ultrastrong, stiff, and lightweight nanotube fibers. Here, for the first time, an important observation of a double‐peak behavior of the tensile properties, as a function of the twist angle, that is different from the single peak of traditional fibers is reported. Raman spectra show that the new peak arises from the collapse of nanotubes, showing a strong “nano” element in applying the ancient draw‐and‐twist technique, besides the downsizing. A qualitative continuum model is also presented to describe the collapse‐induced enhancement as well as traditional fibers. Our combined experimental and theoretical studies indicate the direction of full utilization of the nano element in improving the mechanical properties of nanotube fibers.
Phosphorylation of Sox2 Cooperates in Reprogramming to Pluripotent Stem Cells
Authors: Jeong Chul-Ho , Cho Yong-Yeon , Kim Myoung-Ok , Kim Sung-Hyun , Cho Eun-Jin , Lee Sung-Young , Jeon Young-Jin , Yeong Lee Kun , Yao Ke , Keum Young-Sam , Bode Ann M. , Dong Zigang 
Published: October 2010

Abstract
Somatic cells can be reprogrammed into induced pluripotent stem cells (iPSCs) by transduction of reprogramming factors, including Oct4, Sox2, Klf4, and c-Myc. A coordinated network of these factors was suggested to confer a pluripotency of iPSCs. Together with Oct4, Sox2 plays a major role as a master regulator in ESCs. However, the underlying mechanisms by which Sox2 contributes to self-renewal or reprogramming processes remain to be determined. Here, we provide new evidence for a phosphorylation-based regulation of Sox2 activity. Akt directly interacts with Sox2 and promotes its stabilization through phosphorylation at Thr118, which enhances the transcriptional activity of Sox2 in ESCs. Moreover, phosphorylation of Sox2 cooperates in the reprogramming of mouse embryonic fibroblasts by enabling more efficient induction of iPSCs. Overall, our studies provide new insights into the regulatory mechanism of Sox2 in ESCs and also provide a direct link between phosphorylation events and somatic cell reprogramming.
Antibacterial Effect of Human Mesenchymal Stem Cells Is Mediated in Part from Secretion of the Antimicrobial Peptide LL-37
Authors: Krasnodembskaya Anna , Song Yuanlin , Fang Xiaohui , Gupta Naveen , Serikov Vladimir , Lee Jae-Woo , Matthay Michael A. 
Published: October 2010

Abstract
Recent in vivo studies indicate that mesenchymal stem cells (MSCs) may have beneficial effects in the treatment of sepsis induced by bacterial infection. Administration of MSCs in these studies improved survival and enhanced bacterial clearance. The primary objective of this study was to test the hypothesis that human MSCs possessed intrinsic antimicrobial properties. We studied the effect of human MSCs derived from bone marrow on the bacterial growth of Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria. MSCs as well as their conditioned medium (CM) demonstrated marked inhibition of bacterial growth in comparison with control medium or normal human lung fibroblasts (NHLF). Analysis of expression of major antimicrobial peptides indicated that one of the factors responsible for the antimicrobial activity of MSC CM against Gram-negative bacteria was the human cathelicidin antimicrobial peptide, hCAP-18/LL-37. Both m-RNA and protein expression data showed that the expression of LL-37 in MSCs increased after bacterial challenge. Using an in vivo mouse model of E. coli pneumonia, intratracheal administration of MSCs reduced bacterial growth (in colony-forming unit) in the lung homogenates and in the bronchoalveolar lavage (BAL) fluid, and administration of MSCs simultaneously with a neutralizing antibody to LL-37 resulted in a decrease in bacterial clearance. In addition, the BAL itself from MSC-treated mice had a greater antimicrobial activity in comparison with the BAL of phosphate buffered saline (PBS)-treated mice. Human bone marrow-derived MSCs possess direct antimicrobial activity, which is mediated in part by the secretion of human cathelicidin hCAP-18/ LL-37.
A 9‐mW Continuous‐time Hybrid Active–Passive ΣΔ Modulator with 84‐dB Dynamic Range
Authors: Ye Tianfeng , Zhang Yi , Hong Zhiliang , Liu Bill Yang 
Published: October 2010

AbstractA hybrid active–passive, continuous time (CT) sigma–delta (ΣΔ) modulator with a multibit quantizer is presented. The modulator is designed as a fifth‐order, dual‐loop architecture, allowing for a maximum quantizer delay of half a clock period. By removing the summing block before the quantizer as well as by introducing an active–passive hybrid loop filter, the design achieves high signal‐to‐noise ratio (SNR) comparable to a fourth‐order active design while dissipating power equivalent to a third‐order implementation. A data‐weighted averaging (DWA) algorithm implemented with analog reference shuffling is utilized to suppress the mismatches in the current‐steering digital‐to‐analog conversion (DAC) with no extra delay introduced between the quantizer and DAC. The chip, manufactured in a 1.8‐V, 0.18‐µm complementary metal oxide semiconductor (CMOS) process, experimentally achieves 79.5 dB peak SNR, 78 dB peak signal‐to‐noise‐and‐distortion ratio (SNDR), and 84‐dB dynamic range over a 1‐MHz signal bandwidth. The 0.43‐mm2test chip consumes 9‐mW of power when clocked at 128 MHz. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Finding All DC Solutions of Diode and BJT Circuits by Interval Method and Modified LP‐Narrowing Technique
Authors: Uatrongjit Sermsak 
Published: October 2010

AbstractThe method based on the interval algorithm is one of the techniques used to find all direct current operating points of nonlinear circuits. Many approaches have been proposed to enhance the efficiency of the interval method. Amongst them, the linear programming narrowing (LP‐narrowing) strategy has been proposed and it shows very promising results. In this paper, a modification of the LP‐narrowing technique is proposed. The proposed technique is applied with the interval‐based method to find all direct current solutions of a circuit whose nonlinear elements are only diodes and bipolar junction transistors. It employs the voltage‐current characteristic of diodes to contract the size of the box under consideration before applying the interval operator. The proposed technique has been implemented by using the C‐XSC Toolbox and the GNU Linear Programming Kit package (GLPK). Its performance is evaluated by testing with some nonlinear circuits. The results indicate that the proposed technique can reduce the number of search boxes and improve the computation time. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Design of Fourth‐Order Continuous‐Time Bandpass ΔΣAD Modulator for RF Sampling
Authors: Lin Haijun , Lo Ré Pascal , Iizuka Kunihiko , Kobayashi Haruo , Takai Nobukazu 
Published: October 2010

AbstractThis paper presents the design of a fourth‐order continuous‐time bandpass ΔΣAD modulator for RF sampling. It employs subsampling, RF DAC, as well as digital techniques to compensate for finite Q and excess loop delay, and its loop filter uses inverter‐type OTAs; these basic techniques have been described in our previous papers. This paper validates a transistor‐level circuit design of a complete fourth‐order modulator that combines all of the above techniques, and its SPICE simulation results are as follows: the center of the signal band is 2.4 GHz, the sampling frequency is 3.2 GHz, the signal bandwidth is 2 MHz, the peak SNDR is 56 dB, the power consumption from a 1.8‐V supply voltage is 50 mW, and it uses TSMC 0.18‐µm CMOS process. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
A Novel Boost Class‐D Amplifier Using an H‐bridge Circuit
Authors: Tsuchiya Hirotaka , Michitaka Yoshino , Shinkawa Naoto , Akaba Hiroyuki , Yasuda Akira 
Published: October 2010

AbstractA novel class‐D amplifier with a boost mode is proposed. It solves a problem that cannot boost the signal over a power supply voltage when a certain power supply given. The proposed amplifier can output higher voltages than the power supply voltage. Since the boost DC–DC converter circuit and the class‐D amplifier utilize similar switching circuits, the boost DC–DC function is implemented within the class‐D amplifier circuit. The half‐bridge circuit utilized in a conventional class‐D amplifier is replaced with an H‐bridge circuit. The simulation results show that the output voltage swing is twice that of the power supply voltage without an external boost DC–DC converter. The signal‐to‐noise ratio and third‐harmonic distortion are 103.5 dB and 0.0058%, respectively. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Researches on Cascaded Photovoltaic Modular Systems for Performance Improvement with Power Margin Evaluation
Authors: Xu Qingshan , Sun Xiangdong , Yukita Kazuto , Goto Yasuyuki , Ichiyanagi Katsuhiro 
Published: October 2010

AbstractPhotovoltaic/converter modular systems offer flexibility with maximum power point tracking (MPPT) of the individual modules to decrease module mismatching losses, especially for building integrated photovoltaic (PV) systems. For achieving relatively high voltage outputs, a cascaded configuration is usually preferred at the same time. However, due to efficiency reasons, i.e. the general limit of conversion ratio, issues emerge in which not all modules can actually operate at optimal levels. This paper discusses the main issues encountered, and proposes a novel approach to evaluate power margins of PV modules at different operating levels, which can be an auxiliary criterion for judging whether some modules with lower irradiation should be bypassed or not in such cascaded configurations. Representative cases are investigated, and simulation results testify the validity of evaluating the potential and available power. The proposed approach can also be applied for practical MPPT of photovoltaic generation systems. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Split Process of Low‐Pressure Arc Cathode Spots on SS400(Fe + C) Surface with Oxide Layer
Authors: Kamishima Shinya , Iwao Toru , Yumoto Motoshige 
Published: October 2010

AbstractA remarkable characteristic of a cathode spot of a low‐pressure arc is that the cathode spot moves around on the metal surface. A cathode spot can remove an oxide layer. Cathode spots of low‐pressure arcs have been used for cleaning metal oxide surfaces. However, the influence of an oxide layer on the cathode spot movement remains unclear. As described herein, the cathode spot movements on the oxide layer surface and on the metal surface were measured to determine the cathode spot movement. Experiments were performed using an SS400 cathode and a cylindrical copper anode. A high‐speed video camera recorded the cathode spot movement. Then the obtained images were analyzed using plasma image processing. The cathode spot movement was generated mainly on the boundary layer, but sometimes on the processed surface. The first spot remains at the boundary when the cathode spot splits; the second spot moves on the bulk surface and reappears at a different boundary. Therefore, the cathode spot does not appear suddenly; instead, it moves continuously during the splitting process. The oxide layer serves an important role for cathode spot existence because of oxide layer vaporization. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Neural Network‐based Algorithm for Harmonic Analysis of Industrial Systems Using Asynchronous Simulations in Time and Frequency Domains
Authors: Hooshmand Rahmat A. , Noohi Saeid 
Published: October 2010

AbstractNonlinear loads used in industrial systems cause harmonic pollution in power system voltages and currents. Therefore, it is necessary to estimate properly the propagation of voltage and current harmonic distortions at power system buses in order to eliminate the harmonics. On the other hand, power system harmonic analysis methods can be used to avoid direct measurement of the harmonics. In this paper, a neural network (NN) based algorithm for harmonic analysis of industrial systems (i.e., systems whose topology rarely changes during the year) is proposed. In the meantime, an asynchronous simulation of the system in time and frequency domains is used to avoid the complications of some hybrid methods. Due to the use of time domain simulation to obtain the harmonic currents injected by nonlinear devices, in addition to giving acceptable precision, the method is completely independent of the measurement system. Application of NN for modeling nonlinear loads along with the use of an appropriate fast harmonic analysis procedure in frequency domain has resulted in acceptable execution time in the presented algorithm. The results obtained by modeling and simulation of the Sn‐coating unit of the Mobarakeh integrated steel making plant demonstrate the high accuracy and acceptable execution time of the proposed method. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Virtual Wattmeter Power Consumption Billing Division for Building Air‐Conditioners Supporting User's Energy Saving Intention
Authors: Ninagawa Chuzo , Sato Tomotaka , Kawakita Yahiko , Matsumura Noriaki 
Published: October 2010

AbstractThis paper provides a field test of a new power consumption billing division for building air‐conditioning systems. Since almost all power is consumed by a shared outdoor unit, power consumption bill must be logically divided among each tenant's indoor unit without using any physical meters. First, the paper discusses the algorithm of our ‘virtual wattmeter’ method for a logical division of the power consumption. Our field test result shows that the correlation coefficient between set room temperature and billing division was significant, and shifting the set temperature by 1°C had the effect of decreasing the hourly billing division by 21%. Thus, our virtual wattmeter is a unique method that can reflect the user's energy‐saving intention by adjusting the set temperature on the power consumption billing division. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.