bluuebunny/crossref_metadata_2025_split huggingface dataset:
Density Functional Study of Two Seven‐Membered Unconventional Fullerenes C58F17CF3 and C58F18
Authors: Tang Chunmei , Zhu Weihua , Deng Kaiming 
Published: September 2010

AbstractThe density functional method is used to study the structure, electronic properties, static linear polarizabilities, and optical absorption spectra of two seven‐membered unconventional fullerene derivatives C58F17CF3 and C58F18. It is calculated that three sites chosen to locate the CF3 are isoenergetic. The energy gaps of C58F18 and C58F17CF3 are much larger than that of C58, indicating the fluorination and trifluoromethylation of C58 can remarkably enhance the kinetic stability. The density of states explore that the influence of CF3 to the energy levels is mainly distributed in the energy range from −10 to −2 eV. However, when the CF3 substitutes for F in C58F18, the bond lengths, energy gaps, static linear polarizabilities, and optical absorption spectra all show small variety.
DFT Study for the Reduction of N2O(1Σ+) with CO(1Σ+) Catalyzed by Cr+
Authors: Liu Fengxia , Zhang Jianhui , Hu Minzhe , Wang Yongcheng , Leng Yanli 
Published: September 2010

AbstractThe mechanism of the reaction N2O(1Σ+)+CO(1Σ+)→N2(1Σ)+CO2(1Σ) catalyzed by Cr+ has been investigated on sextet and quartet potential energy surfaces. The reactions are studied by using the UB3LYP density functional method and the standard 6‐311+G(2d) basis sets. The geometries for reactants, the transition states and the products are completely optimized. The result shows that the reaction proceeds in a two‐step manner, each mechanism are insertion‐elimination and rearrangement mechanism. The involved crossing between the two potential energy surfaces have been discussed by means of the intrinsic reaction coordinate (IRC) approach, and the crossing points (CPs) are located. The minimum energy crossing point (MECP) that we obtained by the mathematical algorithm proposed by Harvey et al. has been also employed. Then the action of frontier molecular orbitals in MECPs were illuminated briefly. Finally, O‐atom affinities (OA) testified that the argumentation is thermodynamically allowed.
Syntheses, Crystal Structures and Luminescent Properties of a Dimeric Complex [(bzdmpzm)Cu(µ‐I)]2 and a Polymeric Complex [(bzdmpzm)Cu(µ‐NCS)]n (bzdmpzm=Bis(4‐benzyl‐3,5‐dimethyl‐1H‐pyrazol‐1‐yl)methane)
Authors: Wang Huihui , Li Hongxi , Ren Zhigang , Chen Yang , Lang Jianping 
Published: September 2010

AbstractReactions of CuX (X=I, NCS) with bis(4‐benzyl‐3,5‐dimethyl‐1H‐pyrazol‐1‐yl)methane (bzdmpzm) in MeCN resulted in the formation of one dimer [(bzdmpzm)Cu(µ‐I)]2 (1) and one 1D polymer [(bzdmpzm)Cu(µ‐NCS)]n (2) in high yields. 1 and 2 were characterized by elemental analysis, IR, 1H NMR spectra, powder X‐ray diffraction and single‐crystal X‐ray diffraction. 1 consists of two scorpion‐like [(bzdmpzm)Cu]+ fragments bridged by two iodides, forming a dimeric structure. 2 contains a unique 1D scolopendra‐like chain of [(bzdmpzm)Cu]+ fragments linked by pairs of thiocyanates. The luminescence properties of 1 and 2 were also investigated.
Heterodimers of Histidine and Amantadine as Inhibitors for Wild Type and Mutant M2 Channels of Influenza A
Authors: Zhang Wenjuan , Xu Jing , Liu Fang , Li Chufang , Jie Yanling , Chen Shaopeng , Li Zhiyuan , Liu Jinsong , Chen Ling , Zhou Guochun 
Published: September 2010

AbstractInhibitors bearing the imidazole, adamantane and related structures were synthesized and tested against WT, S31N and S31N‐L26I mutant M2 channels. Although amantadine (1) only inhibited WT M2 channel, compound 6 containing the imidazole and adamantane groups showed good inhibitory activity to WT and mutant M2 channels. The stereochemistry and basic pKa of α‐amine are important for the activity of inhibitors and our data showed that derivatives of natural histidine are more active for M2 channels than those of unnatural histidine. The significance of our present results is that we have established a prospective strategy of drug discovery of WT and mutant M2 channels against influenza A.
Equilibrium Studies on Reactive Extraction of α‐Cyclohexyl‐mandelic Enantiomers Using Hydrophilic β‐Cyclodextrin Derivatives Extractants
Authors: Tang Kewen , Miao Jiabing , Liu Yongbing , Zhou Tao , Song Litao 
Published: September 2010

Abstractβ‐Cyclodextrin (β‐CD) is negligibly soluble in organic liquids and can be modified to achieve a higher solubility in water. In this paper, racemic α‐cyclohexyl‐mandelic acid (α‐CHMA) was separated by chiral reactive extraction with aqueous β‐cyclodextrin derivatives. Hydroxypropyl‐β‐cyclodextrin (HP‐β‐CD), hydroxyethyl‐β‐cyclodextrin (HE‐β‐CD), and methyl‐β‐cyclodextrin (Me‐β‐CD) were selected as chiral selectors for reactive extraction of α‐CHMA enantiomers from organic phase to aqueous phase. Factors affecting the extraction efficiency were investigated, including the types of organic solvents and β‐CD derivatives, the concentrations of the chiral selector and α‐CHMA enantiomers, pH and temperature. The experimental results demonstrate that HP‐β‐CD, HE‐β‐CD, and Me‐β‐CD have stronger recognition abilities for S‐α‐CHMA than for R‐α‐CHMA. Among the three derivatives, HP‐β‐CD shows the strongest separation factor for α‐CHMA enantiomers. A high enantioseparation efficiency with a maximum separation factor (α) of 2.02 is observed at pH 2.5 and 5°C.
A Novel Sample Pretreatment Method for the Analysis of Polybrominated Diphenyl Ethers in Polymers of Waste Electrical and Electronic Equipment (WEEE)
Authors: Huang Fan , Meng Xiangzhou , Chen Ling , Xiang Nan , Liu Ying , Li Guangming 
Published: September 2010

AbstractA fast sample pretreatment method was developed to determine polybrominated diphenyl ethers (PBDEs) in polymers from waste electrical and electronic equipment (WEEE). Polymers were firstly prepared into "polymer film" to facilitate a complete Soxtec extraction. Then, three extraction parameters (including hot plate temperature, boiling time, and rinsing time) were optimized based on the recovery of target in reference polymer samples. The proposed method was successfully applied to the analysis of PBDEs in standard plastic materials from WEEE and the extraction yields of PBDEs ranged from 78.9% to 91.3%. The detection limits of PBDEs were 0.05–0.10 µg/g, indicating this method can be used as a quality assurance and quality control procedure of PBDEs in the production of electrical and electronic equipment.
Polymer Light‐emitting Diodes Based on End‐capped Poly[9,9‐di‐(2′‐ethylhexyl)fluorenyl‐2,7‐diyl]
Authors: Zhang Qiushu 
Published: September 2010

AbstractWe demonstrate polymer light‐emitting diodes (LEDs) based on poly[9,9‐di‐(2′‐ethylhexyl)fluorenyl‐2,7‐diyl] with end capper dimethylphenyl or N,N‐bis(4‐methylphenyl)‐N‐phenylamine. The introduction of end‐capper groups increased the device luminance and efficiency, while greatly depressing the green emission. For the devices constructed of poly[9,9‐di‐(2′‐ethylhexyl)fluorenyl‐2,7‐diyl] end capped with dimethylphenyl, the maximum luminance reached 381 cd/m2 at 122 mA/cm2. The maximum external quantum efficiency was 0.16% at 117 mA/cm2, which is more than five times higher than that of the non‐end‐capped polymer LEDs. The electroluminescence (EL) maximum was at 485 nm, blue shifted by 52 nm with respect to that of the non‐end‐capped polyfluorene devices. It is proposed that efficient hole trapping at end capper and increased resistance of polyfluorene to oxidation are responsible for the improved device performance and color stability.
Preparation of Au Nanoparticles on Surface of Two Supports by Adsorption Phase Synthesis
Authors: Jiang Xin , Wang Ting , Chen Shi 
Published: September 2010

Abstract By utilizing adsorption phase synthesis (APS), Au nanoparticles were prepared on the surface of SiO2 with or without modification by Ni(OH)2. TEM, XRD, and UV‐vis were employed to characterize the morphology of Au particles on the surface of two kinds of supports. The results showed that the average size of Au particles on the SiO2 surface modified by Ni(OH)2 was less than 5 nm. Due to high surface isoelectric point, Au particles formed in the adsorption layer were prone to distribute on the surface of SiO2 modified by Ni(OH)2. With content of Ni(OH)2 in samples increasing, more Au particles with small size appeared on the support surface.
An Efficient and Economical Method for the Preparation of Fmoc‐Argω,ω′(Boc)2‐OH
Authors: Zhu Ruixin , Xie Ming , Wang Fei , Liu Qi , Kang Tingguo 
Published: September 2010

AbstractThe arginine derivative Fmoc‐Argω,ω′(Boc)2‐OH has been prepared in perfect yield starting from Fmoc‐Orn·HCl and N,N′‐di‐Boc‐N′′‐triflyguanidine with the presence of diisopropylethylamine (DIEA). This work provides an efficient and economical method for the preparation of this compound.
Renin Inhibitors in Chronic Heart Failure: The Aliskiren Observation of Heart Failure Treatment Study in Context
Authors: Krum Henry , Maggioni Aldo 
Published: September 2010

AbstractRenin‐angiotensin aldosterone system (RAAS) activation is a key neurohormonal contributor to the progression of chronic heart failure. Strategies that block this activation have consistently demonstrated major beneficial impacts on morbidity and mortality in this setting. Direct renin inhibitors (DRIs) present a novel opportunity to block at an additional or alternative step in this pathway, that being conversion of angiotensinogen to angiotensin I. Theoretical benefits of blocking at the level of renin include: inhibition of the reflex activation of plasma renin activity induced by conventional downstream RAAS blockers. Minimization of angiotensin II and/or aldosterone escape and blocking upstream at the rate‐limiting step of angiotensin I production. Preclinical and early‐phase clinical studies have largely supported this hypothesis. In the Aliskiren Observation of Heart Failure Treatment study, patients with systolic chronic heart failure receiving background angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blockers and β‐blockers benefited from aliskiren in reduction vs placebo of plasma levels of brain natriuretic peptide, the primary efficacy endpoint of that study. Large‐scale outcome trials are, however, required to definitively determine the benefits of a DRI strategy additional to, or as an alternative to, conventional approaches such as ACE inhibitors in the systolic chronic heart failure setting. Copyright © 2010 Wiley Periodicals, Inc.The authors have no funding, financial relationships, or conflicts of interest to disclose.
Evaluation of River Water Quality Simulations at a Daily Time Step – Experience with SWAT in the Axe Catchment, UK
Authors: Glavan Matjaž , White Sue , Holman Ian P. 
Published: September 2010

AbstractThe Water Framework Directive (WFD) was established for the protection of surface waters (rivers, lakes, transitional and coastal waters) and ground waters in the European Union. The main environmental objective is to achieve and maintain a good status for all waters by the target date of 2015. Models which are able to address the majority of environmental objectives are proposed within the WFD to inform the management changes required to meet current water policy goals. The use of the Soil and Water Assessment Tool (SWAT) catchment model is widespread throughout the world, especially to support river basin management as required by the WFD. This paper provides a critical evaluation of the use of the model by placing model performance in the Axe catchment, UK, in the context of international performance of the model. Within the constraints of the available data, SWAT represents hydrology, sediment and ortho‐phosphorus concentration well for this heterogeneous catchment, but the representation of daily nitrogen concentration dynamics is poor. Temporal aggregation of model outputs from daily to monthly improved the performance metrics for all the river outputs, including nitrate. Wider review of SWAT studies showed widespread reporting of monthly performance metrics within the SWAT studies, despite the model operating at a daily time step. Poor performance for nitrate identified in this current study may be a significant factor in the choice to not report daily results. This demonstrates the importance of ascertaining the reasons for the use of temporal aggregation in modelling studies.
Composition of the migratory mass during development of the olfactory nerve
Authors: Miller Alexandra M. , Treloar Helen B. , Greer Charles A. 
Published: September 2010

AbstractThe embryonic development of the olfactory nerve includes the differentiation of cells within the olfactory placode, migration of cells into the mesenchyme from the placode, and extension of axons by the olfactory sensory neurons (OSNs). The coalition of both placode‐derived migratory cells and OSN axons within the mesenchyme is collectively termed the “migratory mass.” Here we address the sequence and coordination of the events that give rise to the migratory mass. Using neuronal and developmental markers, we show subpopulations of neurons emerging from the placode by embryonic day (E)10, a time at which the migratory mass is largely cellular and only a few isolated OSN axons are seen, prior to the first appearance of OSN axon fascicles at E11. These neurons also precede the emergence of the gonadotropin‐releasing hormone neurons and ensheathing glia which are also resident in the mesenchyme as part of the migratory mass beginning at about E11. The data reported here begin to establish a spatiotemporal framework for the migration of molecularly heterogeneous placode‐derived cells in the mesenchyme. The precocious emigration of the early arriving neurons in the mesenchyme suggests they may serve as “guidepost cells” that contribute to the establishment of a scaffold for the extension and coalescence of the OSN axons. J. Comp. Neurol. 518:4825–4841, 2010. © 2010 Wiley‐Liss, Inc.
Multiresolution algorithms for the numerical solution of hyperbolic conservation laws
Authors: Harten Ami 
Published: September 2010

AbstractGiven any scheme in conservation form and an appropriate uniform grid for the numerical solution of the initial value problem for one‐dimensional hyperbolic conservation laws we describe a multiresolution algorithm that approximates this numerical solution to a prescribed tolerance in an efficient manner. To do so we consider the grid‐averages of the numerical solution for a hierarchy of nested diadic grids in which the given grid is the finest, and introduce an equivalent multiresolution representation. The multiresolution representation of the numerical solution consists of its grid‐averages for the coarsest grid and the set of errors in predicting the grid‐averages of each level of resolution in this hierarchy from those of the next coarser one. Once the numerical solution is resolved to our satisfaction in a certain locality of some grid, then the prediction errors there are small for this particular grid and all finer ones; this enables us to compress data by setting to zero small components of the representation which fall below a prescribed tolerance. Therefore instead of computing the time‐evolution of the numerical solution on the given grid we compute the time‐evolution of its compressed multiresolution representation. Algorithmically this amounts to computing the numerical fluxes of the given scheme at the points of the given grid by a hierarchical algorithm which starts with the computation of these numerical fluxes at the points of the coarsest grid and then proceeds through diadic refinements to the given grid. At each step of refinement we add the values of the numerical flux at the center of the coarser cells. The information in the multiresolution representation of the numerical solution is used to determine whether the solution is locally well‐resolved. When this is the case we replace the costly exact value of the numerical flux with an accurate enough approximate value which is obtained by an inexpensive interpolation from the coarser grid. The computational efficiency of this multiresolution algorithm is proportional to the rate of data compression (for a prescribed level of tolerance) that can be achieved for the numerical solution of the given scheme.
Study on the mechanism of potential response of a ketamine‐sensitive membrane electrode
Authors: Ling Yunyun , Yang Ya , Bian Shizhong , Tu Yifeng 
Published: September 2010

AbstractThe response mechanism of a simple device for the rapid detection of ketamine with ‘in the field’ capabilities is investigated. The mechanism is a membranous ketamine ionic selective electrode (ISE) with partly carboxylated PVC as matrix andortho‐nitrophenyloctyl ether (o‐NPOE) as plasticizer. The experimental results reveal that the inclusion of the plasticizer in the membrane significantly increased the response. A mechanism is proposed where the infiltration of a target species into the membrane is capable of producing a superior response. This response process is non‐selective for species with similar molecular structure and size. This new research addresses some omissions and misapprehension in the literature where the mechanism was reported as an ion‐exchange‐induced response. In this research the ion‐exchange‐induced response was measurable after the elimination of the infiltration‐induced response extending to lower concentration ranges and thus providing the potential for better sensitivity and selectivity. Copyright © 2010 John Wiley & Sons, Ltd.
The state of the art of residue analysis: the 6th VDRA symposium 2010
Authors: De Brabander H. F. , Vanden Bussche J. , Wille K. , Bekaert K. , Vanhaecke L. 
Published: September 2010

AbstractSince the onset of residue analysis (ca 40 years ago) a lot of attention has been paid to the amelioration of analytical methods, for example, lowering the limits of detection (LOD) and limits of quantification (LOQ) or decision limits (CCα) and detection capabilities (CCβ), including an increase in the number of analytes, shortening runtimes, increasing sample throughput, amongst others. The state of the art in residue analysis, which was presented at the VDRA 2010 symposium (Hormone and Veterinary Drug Residue Analysis) in Ghent is reviewed in this article. From an analytical point of view, the use of ultra high performance liquid chromatography (UHPLC) hyphenated with accurate mass spectrometry is often used in combination with other (biological) detection systems and ‘omic’ approaches. Through these techniques more xenobiotic substances turn out to be naturally occurring in some matrices and/or circumstances (e.g. thiouracil, chloramphenicol and semicarbazide). Copyright © 2010 John Wiley & Sons, Ltd.
Optimum and suboptimum channel estimation for the uplink of CDMA mobile radio systems with joint detection
Authors: Steiner Bernd , Jung Peter 
Published: September 2010

AbstractIn the present paper, channel estimation in the uplink of CDMA mobile radio systems with burst transmission applying joint detection is considered. The different radio channels are estimated at the receiver using known midamble codes. Either maximum‐likelihood, i.e. optimum, or suboptimum channel estimation can be realized at the receiver. Several methods for constructing code sets for the simultaneously active users are proposed. It is shown that the structure of the channel estimator for a multi‐user synchronous CDMA mobile radio system is the same as for a single‐user system when the mid amble codes of the users are segments derived from a single basic code. Furthermore, it is shown that the channel estimator can be implemented as a correlator when the midamble codes are constructed from a periodic basic code. Finally, the effect of noisy channel estimation, i.e. the presence of channel estimation errors, on the detected data is examined.
General approach for the comparison of spectrum efficiency of digital mobile radio systems
Authors: Falciasecca G. , Caini C. , Riva G. , Frullone M. 
Published: September 2010

AbstractEvaluation of spectrum efficiency in mobile radio systems is often performed by different authors starting from different working assumptions; that yields results that are not easily comparable outside the “scenario” where they have been achieved. This paper attempts to settle this controversial matter providing some criteria for overcoming these difficulties. The results of this investigation allow to assess that relative capacity comparisons are fairly independent of some quality parameters, such as specified outage probability, or propagation parameters, such as the standard deviation of lognormal shadowing, so that these parameters need not complicate the comparison of competing approaches. As a consequence, a very simple scenario, providing an adequate basis for deriving constant efficiency curves, turns out to be of great relevance for comparisons. Associated with it, a graphic tool, allowing to perform quick relative comparisons among systems, is presented.
Letter: Analysis of concatenated reed‐solomon encoding schemes with full and partial interleaving for short data messages
Authors: Cancellieri Giovanni , Chiaraluce Franco , Guidotti Giovanni 
Published: September 2010

AbstractA concatenation of Reed‐Solomon and repetition codes with symbol interleaving is considered for applications in which the message length is limited and the probability of incorrect received symbols is high. An analysis is developed with reference to a Packet Radio Network, using Spread Spectrum modulation, simultaneously affected by random errors and burst errors. The results obtained are compared with those derived by numerical simulation. It is shown that a canonical formulation can be used for the case of full interleavers, but it cannot be applied to encoding schemes with partial interleavers. In the latter situation a modified, improved, approach is proposed.
Input rate flow control for high speed communications networks using burst level feedback control
Authors: Rubin Izhak , Lin K. David 
Published: September 2010

AbstractWe propose a new input rate flow control scheme wherein the credit increment rate is updated periodically as the loading status varies. Based upon the observed status of each station's burst‐level activity, the network access node distributes feedback control signaling messages to the stations. These signaling messages allow the stations to adapt their credit increment rates in accordance with system burst‐loading conditions. The Generic Flow Control (GFC) field of the ATM cell header can be used to carry information characterizing the burst‐level loading activity at the switch used in the proposed scheme. We also present queueing models to study the system performance at the network access points. For this purpose, we select a sub‐network topology which involves a network switch (such as a fast packet switch in high‐speed metropolitan or wide area networks) and a number of regulated source stations which drive the network switch. To avoid packet retransmissions due to cell losses at the access switch, each user station (or CPN) implements locally a replica of the input regulation scheme. The output traffic streams from the source stations, as regulated by the local input rate control mechanism (and adapted by the status messages), load a packet switch which is modeled as a multiple‐server queueing system. Performance curves are presented to illustrate the statistical queue‐size behavior and message delays at both the source stations and the network switch.
A review of voice, data and video traffic models for ATM
Authors: Cosmas John P. , Petit Guido H. , Lehnert Ralf , Blondia Chris , Kontovassilis Kimon , Casals Olga , Theimer Thomas 
Published: September 2010

AbstractThis paper describes the main statistical features of voice, data and video sources, defines a set of selection criteria for selecting source models for these sources, describes a number of relevant source models for representing these sources and recommends the best source models based on the results of the parameterisation of these models from measured data.