bluuebunny/crossref_metadata_2025_split huggingface dataset:
Economic feasibility of multipath protocols in mobile Internet of Things applications
Authors: Sonntag Sebastian , Suomi Henna 
Published: October 2013

AbstractInternet of Things envisions some services that require both end‐device mobility and high availability or high bandwidth. However, the current environment with a cellular network and single‐path protocols may not guarantee a sufficient service level. Thus, this study evaluates the economic feasibility of using multipath protocols for increased availability and bandwidth when contracting with several cellular operators. By using cost‐efficiency analysis, a model is developed for comparing multipath protocols with their single‐path alternatives. The usage of the model is demonstrated with two potential mobile application scenarios that could benefit either from increased availability or bandwidth. Finland is used as an example market. The benefits of multipath protocols were quantified with an extensive set of handset‐based measurements from Finnish cellular networks. The results of this study indicate that the initial costs of a multipath infrastructure remain relatively small, and the total costs rapidly approach the operational costs as the number or active time of smart devices increase. Therefore, this study indicates that multipath protocols are economically feasible for certain mobile Internet of Things applications, particularly those requiring high bandwidth. Thus, new service models emerging in the Internet could create a real demand for multipath protocols in the future. Copyright © 2013 John Wiley & Sons, Ltd.
Facilitated Transport in Hydroxide‐Exchange Membranes for Post‐Combustion CO2 Separation
Authors: Xiong Laj , Gu Shuang , Jensen Kurt O. , Yan Yushan S. 
Published: October 2013

AbstractHydroxide‐exchange membranes are developed for facilitated transport CO2 in post‐combustion flue‐gas feed. First, a correlation between the basicity of fixed‐site functional groups and CO2‐separation performance is discovered. This relationship is used to identify phosphonium as a promising candidate to achieve high CO2‐separation performance. Consequently, quaternary phosphonium‐based hydroxide‐exchange membranes are demonstrated to have a separation performance that is above the Robeson upper bound. Specifically, a CO2 permeability as high as 1090 Barrer and a CO2/N2 selectivity as high as 275 is achieved. The high performance observed in the membranes can be attributed to the quaternary phosphonium moiety.
Thermoelectric Properties and Electronic Structure of the Zintl‐Phase Sr3AlSb3
Authors: Zevalkink Alex , Pomrehn Gregory , Takagiwa Yoshiki , Swallow Jessica , Snyder G. Jeffrey 
Published: October 2013

AbstractThe Zintl‐phase Sr3AlSb3, which contains relatively earth‐abundant and nontoxic elements, has many of the features that are necessary for good thermoelectric performance. The structure of Sr3AlSb3 is characterized by isolated anionic units formed from pairs of edge‐sharing tetrahedra. Its structure is distinct from previously studied chain‐forming structures, Ca3AlSb3 and Sr3GaSb3, both of which are known to be good thermoelectric materials. DFT predicts a relatively large band gap in Sr3AlSb3 (Eg≈1 eV) and a heavier band mass than that found in other chain‐forming A3MSb3 phases (A=Sr, Ca; M=Al, Ga). High‐temperature transport measurements reveal both high resistivity and high Seebeck coefficients in Sr3AlSb3, which is consistent with the large calculated band gap. The thermal conductivity of Sr3AlSb3 is found to be extremely low (≈ 0.55 W mK−1 at 1000 K) due to the large, complex unit cell (56 atoms per primitive cell). Although the figure of merit (zT) has not been optimized in the current study, a single parabolic band model suggests that, when successfully doped, zT≈ 0.3 may be obtained at 600 K; this makes Sr3AlSb3 promising for waste‐heat recovery applications. Doping with Zn2+ on the Al3+ site has been attempted, but does not lead to the expected increase in carrier concentration.
Electrochemical Properties of Yolk–Shell‐Structured CuO–Fe2O3 Powders with Various Cu/Fe Molar Ratios Prepared by One‐Pot Spray Pyrolysis
Authors: Yang Kwang Min , Hong Young Jun , Kang Yun Chan 
Published: October 2013

AbstractSeveral yolk–shell‐structured CuO–Fe2O3 powders with various Cu/Fe molar ratios have been successfully prepared under equivalent reaction conditions using a one‐pot spray pyrolysis process. The Cu and Fe components are uniformly distributed throughout the powders, irrespective of composition. The Brunauer–Emmett–Teller surface areas of the yolk–shell CuO–Fe2O3 systems increased from 5 to 16 m2 g−1 if the Cu/Fe molar ratios are decreased from 3:1 to 1:3. The initial discharge and charge capacities of the yolk–shell CuO–Fe2O3 system (Cu/Fe=1:2), showing maximum values at a constant current density of 1000 mA g−1, are 1436 and 1012 mA h g−1, respectively. After 130 cycles, the discharge capacities of the yolk–shell CuO–Fe2O3 powders with Cu/Fe molar ratios of 1:3, 1:2, 1:1, 2:1, and 3:1 are 1159, 1151, 755, 655, and 651 mA h g−1, respectively. The discharge capacities of the yolk–shell and dense powder samples after 50 cycles, when subjected to a series of current density increases from 500 to 5000 mA g−1, are 735 and 495 mA h g−1, respectively.
Measurements of SiH4/H2 VHF Plasma Parameters with Heated Langmuir Probe
Authors: Yamane T. , Nakao S. , Takeuchi Y. , Muta H. , Ichiki R. , Uchino K. , Kawai Y. 
Published: October 2013

AbstractThe parameters of a SiH4/H2 VHF plasma were measured as a function of silane gas concentration with a heated Langmuir probe. It was found that when the sailane gas concentration is increased, the nagative ion density increases. Here the negative ion density was estimated from the reduction of the electron saturation current. In addition, the dependence of the wall potential on the silane gas concentration agreed with the theoretical values derived from the Bohm sheath equation including negative ions. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Image thresholding techniques for localization of sub‐resolution fluorescent biomarkers
Authors: Ghaye Julien , Kamat Madhura Avinash , Corbino‐Giunta Linda , Silacci Paolo , Vergères Guy , De Micheli Giovanni , Carrara Sandro 
Published: October 2013

AbstractsIn this article, we explore adaptive global and local segmentation techniques for a lab‐on‐chip nutrition monitoring system (NutriChip). The experimental setup consists of Caco‐2 intestinal cells that can be artificially stimulated to trigger an immune response. The eventual response is optically monitored using immunofluoresence techniques targeting toll‐like receptor 2 (TLR2). Two problems of interest need to be addressed by means of image processing. First, a new cell sample must be properly classified as stimulated or not. Second, the location of the stained TLR2 must be recovered in case the sample has been stimulated. The algorithmic approach to solving these problems is based on the ability of a segmentation technique to properly segment fluorescent spots. The sample classification is based on the amount and intensity of the segmented pixels, while the various segmenting blobs provide an approximate localization of TLR2. A novel local thresholding algorithm and three well‐known spot segmentation techniques are compared in this study. Quantitative assessment of these techniques based on real and synthesized data demonstrates the improved segmentation capabilities of the proposed algorithm. © 2013 International Society for Advancement of Cytometry
Efficient secondary access with intelligent spectrum sensing in cognitive radio networks
Authors: Dai Zeyang , Liu Jian , Sun Zhi , Long Keping 
Published: October 2013

SUMMARYIn cognitive radio networks, cooperative sensing can significantly improve the performance in detection of a primary user via secondary users (SUs) sharing their detection results. However, a large number of cooperative SUs may induce great sensing delay, which degrades the performance of secondary transmissions. In this paper, we jointly consider cooperative sensing and cognitive transmission in cognitive radio networks, aiming to achieve efficient secondary access with low sensing overhead under both the sensing time and reporting power limitations, where primary users are guaranteed to be sufficiently protected. We first propose an adaptive sensing scheme to lower the detection time while not degrading the detection probability. Then, based on the proposed adaptive sensing scheme, an efficient cognitive transmission protocol is well designed, which improves the throughput of secondary transmissions while ensuring the QoS of primary transmissions. We analyze the performance for the proposed secondary access framework in terms of misdetection probability, average detection time and normalized secondary throughput, respectively, and derive their closed‐form expressions over Rayleigh fading channels with considering the reporting errors accordingly. We also study the problems of optimizing the number of cooperative SUs to minimize the misdetection probability and average detection time, and maximize the normalized secondary throughput for proposed framework. Simulation results reveal that the proposed framework outperforms the traditional case significantly. Copyright © 2013 John Wiley & Sons, Ltd.
Cooperative quadrature physical layer network coding in wireless relay networks
Authors: Yang Hongjuan , Chong Peter H. J. , Meng Weixiao , Li Bo , Guan Yong Liang 
Published: October 2013

SUMMARYThis paper proposes a cooperative quadrature physical layer network coding (CQPNC) scheme for a dual‐hop cooperative relay network, which consists of two source nodes, one relay node and one destination node. All nodes in the network have one antenna, and the two source nodes transmit their signals modulated with quadrature carriers. In this paper, a cooperative quadrature physical layer network coded decode‐and‐forward (DF) relay protocol (CQPNC‐DF) is proposed to transmit the composite information from the two source nodes via the relay node to the destination node simultaneously to reduce the number of time slots required for a transmission. The proposed CQPNC‐DF relay protocol is compared with time‐division multiple‐access amplify‐and‐forward (TDMA‐AF), TDMA‐DF, cooperative network coded DF (CNC‐DF) and cooperative analog network coded AF (CANC‐AF) relay protocols to demonstrate its effectiveness in terms of bit error rate (BER) and system throughput under different propagation conditions. The simulation results reveal that the proposed CQPNC‐DF relay protocol can significantly improve the network performance. Compared with two TDMA schemes and CNC‐DF, the proposal can provide up to 100% and 50% throughput gains, respectively. Moreover, no matter what the scene, the proposed scheme always has the lowest BER in the low SNR region. Copyright © 2013 John Wiley & Sons, Ltd.
Time domain leakage in DFT‐based channel estimation for OFDM systems with guard bands
Authors: Fahmy Y. A. , Hafez H. , Khairy M. M. 
Published: October 2013

SUMMARYIn this paper, a mathematical analysis of the time domain leakage problem in the discrete Fourier transform (DFT) based channel estimation technique is presented. The time domain leakage is because of the absence of pilots in the guard band. Several solutions to this problem were previously proposed based on reducing the leakage in the frequency domain. These solutions significantly increase the receiver complexity. In this paper, the root cause of the leakage problem is linked to the time domain and a modification is proposed carrying slight additional complexity over the conventional DFT‐based estimator. Performance evaluation is assessed in terms of the bit error rate and the mean square error. The proposed modification significantly decreases the error floor of the conventional DFT‐based channel estimation technique. In addition, its performance is comparable to other more complex techniques recently proposed.Copyright © 2013 John Wiley & Sons, Ltd.
On the Reactivity of Platina‐β‐diketone and Acetylplatinum(II) Complexes toward 2‐(Diphenylphosphanyl)benzaldehyde and Its Dioxolane Derivative
Authors: Kluge Tim , Mendicute‐Fierro Claudio , Bette Martin , Rodríguez‐Diéguez Antonio , Garralda Maria A. , Steinborn Dirk 
Published: October 2013

AbstractThe dinuclear platina‐β‐diketone [Pt2{(COMe)2H}2(μ‐Cl)2] (1) reacts with four and two equivalents of 2‐[2‐(diphenylphosphanyl)phenyl]‐1,3‐dioxolane (L1) to yield [Pt(COMe)Cl(PPh2{o‐C6H4CH(O2C2H4)}‐κP)2] (3) and [Pt(COMe)Cl(PPh2{o‐C6H4CH(O2C2H4)}‐κP,κO)] (4), respectively. The weak Pt–O bond in 4 can be easily broken up by stronger donors. Thus, complex 4 reacts with PPh3 to yield [Pt(COMe)Cl(PPh3)(PPh2{o‐C6H4CH(O2C2H4)}‐κP)] (5) and [Pt(COMe)Cl(PPh3)2] (6) as well as with L1 to yield 3. Diacetylbis(amine)platinum(II) complexes cis‐[Pt(COMe)2(NH2R)2] (R = Bn, 2a; R = Et, 2b; Bn = benzyl) react with L1 with the substitution of one amine ligand to yield [Pt(COMe)2(NH2R)(PPh2{o‐C6H4CH(O2C2H4)}‐κP)] (R = Bn, 7a; R = Et, 7b). The unprotected 2‐(diphenylphosphanyl)benzaldehyde (L2) reacts with the platina‐β‐diketone 1 by oxidative C–H addition followed by reductive elimination of acetaldehyde to form [PtCl{PPh2(o‐C6H4CO)‐κP,κC}{PPh2(o‐C6H4CHO)‐κP}] (8). On the other hand, the reactions of diacetylbis(amine)platinum(II) complexes 2a/b and L2 proceeded with Schiff base formation and, thus, yielded complexes bearing hemiaminal–phosphane ligands, [Pt(COMe)2(PPh2{o‐C6H4CH(OH)(NHR)}‐κP,κN)] (R = Bn, 9a; R = Et, 9b), and imine–phosphane ligands, [Pt(COMe)2{PPh2(o‐C6H4CH=NR)‐κP,κN}] (R = Bn, 10a; R = Et, 10b). The identities of all platinum complexes were unambiguously proved by microanalyses, high‐resolution mass spectrometric investigations, NMR (1H, 13C, 31P, 195Pt) and IR spectroscopy, and single‐crystal X‐ray diffraction analyses (for 4, 9a). The differences in the reactivity of the aldehyde–phosphane L2 and its acetal‐protected derivative L1 are discussed.
Syntheses, Photoluminescence, and Electroluminescence of Iridium(III) Complexes with Fluorinated 2‐Phenylpyridine as Main Ligands and Tertraphenylimidodiphosphinate as Ancillary Ligand
Authors: Wang Cheng‐Cheng , Jing Yi‐Ming , Li Tian‐Yi , Xu Qiu‐Lei , Zhang Song , Li Wei‐Nan , Zheng You‐Xuan , Zuo Jing‐Lin , You Xiao‐Zeng , Wang Xiu‐Qiang 
Published: October 2013

AbstractThree green‐emitting heteroleptic iridium complexes with 2‐(4,5,6‐trifluorophenyl)pyridine, 2‐(3,4,6‐trifluorophenyl)pyridine, and 2‐(3,4,5‐trifluorophenyl)pyridine as main ligands and tetraphenylimidodiphosphinate (tpip) as the ancillary ligand were synthesized and characterized. The positions of the three fluorine atoms on the phenyl ring affect the emission properties of the complexes, and the application of Htpip as the ancillary ligand improves the electron mobility of the complexes to make it comparable to that of the popular electron transport material tris(8‐hydroxyquinolinato)aluminium (Alq3) under the same electric fields. The organic light‐emitting diodes (OLEDs) based on the above phosphorescent emitters {indium tin oxide (ITO)/1,1‐bis[4‐(di‐p‐tolyl‐amino)phenyl]cyclohexane (TAPC), 30 nm/Ir complex (x wt.‐%)/N,N′‐dicarbazolyl‐3,5‐benzene (mCP), 15 nm/1,3,5‐tri(1‐phenyl‐1H‐benzo[d]imidazol‐2‐yl)phenyl (TPBi), 45 nm/LiF (1 nm)/Al (100 nm)} exhibited good performances. The device doped with bis[2‐(3,4,6‐trifluorophenyl)pyridine](tetraphenylimidodiphosphinato)iridium [Ir(F3,4,6ppy)2(tpip)] (8 wt.‐%) showed superior performance with a peak current efficiency (ηc) of 66.36 cd A–1 and a peak external quantum efficiency (ηext, EQE) of 25.7 % at 5.8 V, a maximum power efficiency (ηp) of 48.20 lm W–1 at 4.4 V, and a maximum luminance (Lmax) of 47627 cd m–2 at 12.6 V. Notably, the electroluminescence (EL) efficiency roll‐off effects at relatively high current density in all devices are very mild, which helps them to obtain high efficiency at brightness. The results suggest that the three complexes, [Ir(F3,4,6ppy)2(tpip)] especially, would have potential applications in OLEDs.
Heterobimetallic Metal–Amidinate Complexes by Stepwise Metalation of Methanetrisamidines
Authors: Gutschank Benjamin , Bayram Melike , Schulz Stephan , Bläser Dieter , Wölper Christoph 
Published: October 2013

AbstractThe acidity of the four N–H groups in methanetrisamidine 1c differs significantly, thereby allowing stepwise metalation by metal organic compounds such as ZnMe2, AlMe3, and GaMe3. Dinuclear complexes 3a–c were formed under kinetic control in the reactions of 1c with 2 equiv. of the metal organic compounds at low temperatures, whereas prolonged reaction times at elevated temperature (100 °C) with 4 equiv. of ZnMe2, AlMe3, and GaMe3 yielded the corresponding tetranuclear complexes 4a–c. The different acidity of the four N–H groups also allowed the stepwise metalation of 1c by two different metal organic complexes with the formation of the heterobimetallic complexes 5a and 5b. In addition, transmetalation by Zn/Al exchange was observed in the reaction of 3c with AlMe3, yielding the corresponding dinuclear aluminium complex 3a. The complexes were characterized by NMR and IR spectroscopy and single‐crystal X‐ray diffraction (3a, 4b, 5a).
Syntheses and Solid‐State Structures of Bis(dialkylstibanyl)sulfanes and ‐telluranes
Authors: Heimann Stefan , Schulz Stephan , Bläser Dieter , Wölper Christoph 
Published: October 2013

AbstractInvited for the cover of this issue is the group of Stephan Schulz at the University of Duisburg‐Essen. The cover image illustrates the in situ crystallization technique, which is the thermally induced transformation of polycrystalline (diethylstibanyl)tellurane, (Et2Sb)2Te, into a single‐crystalline sample by use of an IR laser, which allows melting and recrystallization of the sample in a N2 cooling steam directly on the diffractometer. The technique provides useful structural information for small molecules and allows a detailed investigation of their intermolecular interactions in the solid state.
Synthesis of Oxazole Analogs of Streptolidine Lactam
Authors: Rynearson Kevin D. , Dutta Sanjay , Tran Kiet , Dibrov Sergey M. , Hermann Thomas 
Published: October 2013

AbstractThe streptolidine lactam is an amino acid constituent of streptothricin antibiotics, which inhibit protein synthesis by targeting the bacterial ribosome but suffer from toxicity as a result of the basicity of the aminoimidazole scaffold in the natural products. On the basis of the streptolidine structure, we designed and synthesized oxazole analogs with six‐ and seven‐membered lactam rings as building blocks for RNA‐targeted ligands. These analogs benefit from a dense network of hydrogen‐bond donors and acceptors within a rigid nonplanar heterocyclic system that has attenuated basicity.
Efficient Synthesis of 2‐Substituted Phthalimides from Phthalic Acids in One Step
Authors: Chorell Erik , Chorell Elin 
Published: October 2013

AbstractEfficient procedures for synthesizing 2‐substituted phthalimide (isoindole‐1,3‐dione) analogues starting from phthalic acids have been developed by using experimental design. The phthalimide central fragment frequently appears in biologically active compounds, materials, catalysts, and fluorescent probes, and therefore the development of general, fast, and convenient synthetic methods to this scaffold under neutral, acidic, and basic conditions would be attractive. After an initial screening, the use of acetonitrile, acetic acid, or pyridine in combination with microwave heating proved most promising. Experimental design was applied to these conditions to optimize the time, temperature, and concentration. This strategy has successfully generated synthetic methods that have been used to synthesize a series of phthalimides from phthalic acids and various amines or anilines in excellent yields. The developed methods have proven to be general, fast, convenient, and economic, and thus are expected to have broad utility to efficiently construct novel compounds for future biological and chemical applications.
Total Synthesis of Mycophenolic Acid by a Palladium‐Catalyzed Decarboxylative Allylation and Biomimetic Aromatization Sequence
Authors: Brookes Paul A. , Cordes Jens , White Andrew J. P. , Barrett Anthony G. M. 
Published: October 2013

AbstractThis paper describes the total synthesis of the fungal natural product mycophenolic acid through palladium‐catalyzed allylation, biomimetic cyclization, and aromatization. Methyl (4E)‐6‐hydroxy‐4‐methylhex‐4‐enoate, which was converted in four steps into the key diketo ester dioxinone via two selective C‐acylation reactions, was transformed into a resorcylate. Subsequent phenol methylation, lactonization, iodo‐ether formation, and halogenation gave a tricyclic intermediate. Palladium‐catalyzed cross‐coupling with DABCO–(AlMe3)2 and saponification gave mycophenolic acid. An alternative approach with early stage arene methyl incorporation unexpectedly resulted in the formation of a γ‐pyrone.
Nitrile Oxide versus Nitrone – Switching Regioselectivity of Intramolecular 1,3‐Dipolar Cycloadditions towards the Preparation of Aminopiperidinecarboxylates
Authors: Würdemann Martina , Christoffers Jens 
Published: October 2013

Abstract3‐(Allylamino)‐ and 3‐(propargylamino)propanal were converted via the corresponding oximes into nitrile oxides, which readily underwent intramolecular 1,3‐dipolar cycloadditions to furnish a piperidine‐annulated isoxazole or isoxazoline. The annulated isoxazoline was transformed into orthogonally carbamate‐protected cis‐ and trans‐4‐aminopiperidine‐3‐carboxylates, both representing interesting scaffolds for combinatorial chemistry. Through sequences of amidations and deprotections two triply functionalized products were obtained as examples for diversification. After Boc removal, the piperidino‐annulated isoxazole was also subjected to diversifying reactions, such as reductive amination, amidation, and the formation of sulfonamido‐ and ureido‐substituted derivatives.
Synthesis of Functionalized Pyridine‐2,6‐bis(imidazolines) by Ring Transformation of 4‐(Aminomethyl)oxazoline Derivatives
Authors: Schulz Marvin , Christoffers Jens 
Published: October 2013

AbstractOptically active pyridine‐2,6‐bis(4‐azidomethyloxazoline) was prepared by starting from L‐serine and pyridine 2,6‐dicarboxylic acid. Reduction of the azide moieties gave pyridine‐2,6‐bis(4‐aminomethyloxazoline), which was not a stable compound, but readily underwent a ring‐transforming rearrangement to furnish the pyridine‐2,6‐bis(4‐hydroxymethylimidazoline). After Boc protection of the amidine functionalities, this compound could be further converted into the pyridine‐2,6‐bis(4‐aminomethylimidazoline) via the corresponding bis(azidomethyl) compound. The azide functions of the bis(oxazoline) and the bis(imidazoline) intermediate products could also be further derivatized with an alkyne to give triazoles or through aza‐Wittig reactions with benzaldehyde to give imines.
Catalytic Adsorptive Stripping Chronopotentiometry of Co(II)‐DMG‐Bromate System at an In Situ Plated Lead Film Electrode
Authors: Bobrowski Andrzej , Królicka Agnieszka , Putek Maria , Zarębski Jerzy , Antonatos Nikolas , Economou Anastasios 
Published: October 2013

AbstractA novel catalytic adsorptive stripping chronopotentiometric (CC‐CAdSCP) procedure for the determination of Co(II) traces was developed using a lead film electrode (PbFE). The PbFE was generated in situ on a glassy carbon support from a 0.1 M ammonia buffer containing 1×10−5 M Pb(II), 6.5×10−5 M DMG and the target metals. An addition of 0.2 M NaBrO3 to the solution yielded an 11‐fold catalytic enhancement of chronopotentiometric response of the Co(II)‐DMG complex. The CC‐CAdSCP curves were well‐developed, sharp and reproducible (RSD 5.0 % for 5×10−9 M Co(II)). The limit of detection for Co(II) for 210 s of accumulation time was 4×10−10 M (0.024 µg L−1). In addition, the elaborated method allowed the simultaneous quantification of Co(II) and Ni(II) simultaneously.