bluuebunny/crossref_metadata_2025_split huggingface dataset:
ChemInform Abstract: Synthesis, Anticonvulsant and Toxicity Screening of Newer Pyrimidine Semicarbazone Derivatives.
Authors: Alam Ozair , Mullick Pooja , Verma S. P. , Gilani Sadaf J. , Khan Suroor A. , Siddiqui Nadeem , Ahsan Waquar 
Published: September 2010

AbstractPyrimidine incorporated semicarbazones can be regarded as a newer class of anticonvulsants.
Oxidative dehydrogenation of propane to propene, 1: Kinetic study on V/MgO
Authors: Ramos Raquel , Pina M. Pilar , Menéndez Miguel , Santamaría Jesús , Patience Gregory S. 
Published: September 2010

AbstractThe reaction kinetics of the oxidative dehydrogenation of propane to propene over a V/MgO catalyst were studied. Both propane and propene oxidation kinetics were measured independently to quantify the rates of the parallel and consecutive reactions to propene and carbon oxides. Specific experiments to evaluate reaction products effects showed that water inhibited reaction rates but co‐feeding CO2or propene had no measurable effect on selectivity or conversion. Kinetic data generated under integral reactor conditions and over an inert membrane reactor have also been used to estimate the kinetic parameters. Selectivity decreased as the oxygen partial pressure increased; however, propene yield was relatively insensitive to oxygen concentration. A dual site Mars‐van Krevelen model characterizes the reaction kinetics well. The role of lattice oxygen was established by alternating pulses of propane and oxygen. This redox model is able to predict the experimental tendencies observed in the three types of reactor studied.
Synthesis of Ag/Polypyrrole Core‐Shell Nanospheres by a Seeding Method
Authors: Feng Xiaomiao 
Published: September 2010

AbstractAg/polypyrrole (PPy) core‐shell nanospheres were fabricated through the redox reaction between pyrrole monomer and silver nitrate in the presence of polyvinylpyrrolidone (PVP) and by using the Ag colloidal nanoparticles acting as the seedings. The prepared nanospheres with a shell thickness of 10–12 nm and a core diameter of 20–40 nm are uniform in size and well dispersed. The morphologies, compositions, and electrochemical activities of Ag/PPy composites were characterized by TEM, XRD, FTIR, TGA and CV. The synthetic route employed here is gentle and can be extended to prepare other conducting polymer/inorganic nanocomposites.
Evaluating the Thermal Hazard of Double‐Base Propellant SQ‐2 by Using Microcalorimetry Method
Authors: Xing Xiaoling , Xue Liang , Zhao Fengqi , Gao Hongxu , Pei Qing , Hu Rongzu 
Published: September 2010

AbstractThe thermal decomposition behavior of double‐base rocket propellant SQ‐2 was studied by a Calvet microcalorimeter at four different heating rates. The kinetic and thermodynamic parameters were obtained from the analysis of the heat flow curves. The critical temperature of thermal explosion (Tb), the self acceleration decomposition temperature (TSADT), the adiabatic decomposition temperature rise (ΔTad), the time‐to‐explosion of adiabatic system (t), critical temperature of hot‐spot initiation (Tcr), critical thermal explosion ambient temperature (Tacr), safety degree (SD) and thermal explosive probability (PTE) were presented to evaluate the thermal hazard of SQ‐2.
Ab initio Study of Mechanism of Forming a Germanic Hetero‐Polycyclic Compound between Germylidene (H2C=Ge:) and Acetone
Authors: Lu Xiuhui , Xu Yuehua , Lian Zhenxia , Li Yongqing 
Published: September 2010

AbstractThe mechanism of the cycloaddition reaction of forming a germanic hetero‐polycyclic compound between singlet germylidene (R1) and acetone (R2) has been investigated with CCSD(T)//MP2/6‐31G* method. From the surface energy profile, it can be predicted that the dominant reaction pathway for this reaction consists of three steps: (1) the two reactants (R1, R2) firstly form a twisted four‐membered ring intermediate (INT2); (2) the intermediate (INT2) reacts further with acetone (R2) to give another intermediate (INT4); (3) intermediate (INT4) isomerizes to a hetero‐polycyclic germanic compound (P4) via a transition state TS4. The presented rule of this reaction: the [2+2] cycloaddition effect between the π orbital of germylidene and the π orbital of π‐bonded compounds leads to the formation of four‐membered ring intermediate (INT2). The 4p unoccupied orbital and the lone‐pair sp electrons of Ge in the four‐membered ring intermediate (INT2) react with the π orbital and the antibonding π* orbital of π‐bonded compounds, respectively, forming the π→p and sp→ π* cyclic donor‐acceptor bonds, resulting in the generation of a stable germanic hetero‐polycyclic compound (P4).
Synthesis of Tridentate Ligands Based on Chiral Diamines and Their Application to Enantioselective Friedel‐Crafts Alkylation of Indoles with Nitroalkenes
Authors: Wu Mei , Wang Shoufeng , Xia Chungu , Sun Wei 
Published: September 2010

AbstractA new type of chiral tridentate ligands were prepared and their Zn complexes were examined for the asymmetric Friedel‐Crafts alkylation of indoles with nitroalkenes, which gave rise to good yields and moderate enantioselectivities.
Copper‐Catalyzed Coupling of Thiourea with Aryl Iodides: The Direct Synthesis of Aryl Thiols
Authors: Qiao Shu , Xie Kun , Qi Junsheng 
Published: September 2010

AbstractA general, economical and efficient protocol for the direct copper‐catalyzed coupling of thiourea with aryl iodides is developed and it will be potentially applied in large‐scale industry as a preferred process.
Analysis of the Volatile Components in the Leaves of Cinnamomum camphora by Static Headspace Gas Chromatography Mass Spectrometry Combined with Accurate Weight Measurement
Authors: Zhu Fengjun , Guo Yinlong 
Published: September 2010

AbstractThe volatile components in the leaves of C. camphora were analyzed by static headspace‐gas chromatography/mass spectrometry (HS‐GC‐MS) combined with accurate weight measurement. Accurate weight measurement obtained by Time‐of‐Flight mass spectrometry (TOF‐MS) helped to confirm the identification of volatiles in the analysis. 59 volatile components in the leaves of C. camphora were identified, which mainly included cis‐3‐hexen‐1‐ol (5.6%), 3‐hexen‐1‐ol, acetate (Z) (11.1%), β‐caryophyllene (15.4%), bicyclogermarene (8.4%), trans‐nerolidol (19.5%) and 9‐oxofarnesol (7.7%). The results show that method using HS‐GC‐MS combined with accurate weight measurement achieves reliable identification and has extensive application in the analysis of volatile components present in complex samples.
Simultaneous Determination of Caffeine and Theophylline in Human Plasma with a Weak Cation Monolithic SPE‐column
Authors: Zhu Tao , Row Kyung Ho 
Published: September 2010

AbstractA simple reversed‐phase high performance liquid chromatography (RP‐HPLC) method was developed to determine the level of caffeine and theophylline in human plasma samples. The sample clean‐up step involved the on‐line solid‐phase extraction (SPE) of the analytes from plasma samples into a weak cation monolithic column using a column switching system. Separation was performed on a C18 column (5 µm, 150 mm×4.6 mm) with ultraviolet detection at 274 nm. The mobile phase consisted of methanol‐water (32/68, V/V) under isocratic conditions at a flow rate of 0.6 mL·min−1. The measured concentration of caffeine and theophylline showed a good linear relationship over the concentrations range, 0.1–80.0 µg·mL−1. The absolute recoveries ranged from 77.10% to 85.39%, and the inter‐day and intra‐day relative standard deviations (RSD) were all less than 5%. This method avoids a tedious pretreatment and provides an economic, repeatable and effective method for assaying trace drugs in biological samples.
Diagnostic Value of Poor R‐Wave Progression in Electrocardiograms for Diabetic Cardiomyopathy in Type 2 Diabetic Patients
Authors: Bildirici Ulas , Ural Dilek , Acar Eser , Agacdiken Aysen , Ural Ertan 
Published: September 2010

AbstractBackgroundDiabetic cardiomyopathy (DCMP) is a common complication of diabetes and is associated with increased mortality. It has been suggested that a poor R‐wave progression in a resting electrocardiogram (ECG) could be a sign of cardiomyopathy.HypothesisThe aim of this study was primarily to analyze the relationship between poor R‐wave progression and DCMP, and the effect of poor R‐wave progression on cardiac functions in long‐term follow‐up.MethodsSeventy type 2 normotensive diabetics (33 female, 37 male; mean age, 52.9 ± 10.4 years) were included in the study. Poor R‐wave progression in an ECG was defined as an R wave < 3 mm in V1‐3 derivations. The patients were randomized in 2 groups, which were those without (group I, n = 34) and those with poor R‐wave progression (group II, n = 36). All patients underwent conventional and tissue Doppler echocardiography and were followed in an outpatient clinic setting for 4 years.ResultsDemographic variables were similar between the 2 groups. In group II, left ventricular (LV) relaxation abnormality was more prevalent, the Tei index was higher, and in tissue Doppler mitral annulus Em velocities were significantly lower and Am velocities were higher than those with normal R‐wave progression. At the end of the 4‐year follow‐up period, LV ejection fraction was decreased in group II, whereas LV mass index and Tei index were significantly increased.ConclusionsLV diastolic dysfunction is more frequently observed in diabetic patients with poor R‐wave progression in ECG, which may be an early sign of LV dysfunction and DCMP in diabetics. Copyright © 2010 Wiley Periodicals, Inc.The authors have no funding, financial relationships, or conflicts of interest to disclose.
Guidelines for European workplace drug and alcohol testing in hair
Authors: Agius Ronald , Kintz Pascal 
Published: September 2010

AbstractDrug and alcohol abuse is a concern for many European companies, especially those having safety‐critical jobs. It is not uncommon for European companies to establish a drug policy with little or no provision for drug testing. The European Union (EU) has launched a number of initiatives in its fight against drugs. There is, however, no specific EU legislation and no generally accepted guidelines. Since the outcome of workplace drug testing (WDT) can have serious consequences for the employee, it is of utmost importance that WDT be performed in a defined quality standard and in a legally secured way. In order to fulfil this, the European Workplace Drug Testing Society (EWDTS) has formulated WDT guidelines in order to ensure that the entire drug testing process is of high quality, accredited, and legally defensible, hence giving accurate and reliable information about employee drug use while respecting the privacy of the employee. The aim of this paper is to present the recently formulated guidelines for workplace drug testing in hair. Copyright © 2010 John Wiley & Sons, Ltd.
Simultaneous determination of nitroaromatic compounds in water using capillary electrophoresis with amperometric detection on an electrode modified with a mesoporous nano‐structured carbon material
Authors: Nie Dongxia , Li Ping , Zhang Dan , Zhou Tianshu , Liang Ying , Shi Guoyue 
Published: September 2010

AbstractIn this article, a carbon disk electrode modified with mesoporous carbon material (CMK‐3) was used in CE with amperometric detection system for the simultaneous determination of four types of important nitroaromatic compounds, including 2,4,6‐trinitrotoluene (TNT), 1,3,5‐trinitrobenzene (TNB), 2,4‐dinitrotoluene (DNT) and 1,3‐dinitrobenzene (DNB). Compared with the bare carbon electrode, the CMK‐3 modified electrode greatly improved the sensitivity at a relatively positive detection potential due to its excellent electrocatalytic activities, high conductivity and large effective surface area. The four analytes could be well separated and detected within 480 s. A good linear response was obtained for TNB, DNB, TNT and DNT from 8.4 to 5.0×103 μg/L, with correlation coefficients higher than 0.9992. And the detection limits were established between 3.0 and 4.7 μg/L for the four investigated nitroaromatic compounds (S/N=3). The CMK‐3‐modified electrode was successfully employed to analyze coking wastewater, tap water and river samples with recoveries in the range of 94.8–109.0%, and RSDs less than 5.0%. The presented results demonstrated that the CMK‐3‐modified carbon electrode used in CE with amperometric detection was of convenient preparation, high sensitivity and good repeatability, which could be employed in the rapid determination of practical samples.
Code acquisition in DS‐SSMA systems in the presence of multiple access interference and data modulation
Authors: Corazza Giovanni E. , Esposti Vittorio Degli 
Published: September 2010

AbstractDirect‐Sequence Spread Spectrum Multiple Access (DS‐SSMA) techniques are being proposed for modern personal and mobile radio communication networks. Fast and accurate acquisition of synchronism between the received code sequence and the locally generated sequence plays a fundamental role in the successful utilization of any code division multiple access technique. In this paper, the performance of the code acquisition sub‐system is analysed in the presence of multiple access interference, data modulation and noise. The effect of interference from other codes is analysed without resorting to a Gaussian approximation; this approach allows the evaluation of the properties of different families of codes. Results of the analysis are presented for Maximal Length Shift Register (MLSR), Gold and Kasami sequences, with and without verification mode, with absorbing and non absorbing false alarm state.
Simulation analysis of loss characteristics in ATM switching systems by R1022
Authors: Habermann Reinhard 
Published: September 2010

AbstractIn this paper the results of a simulation analysis concerning the loss characteristics in ATM‐switching systems are presented. The basic model used for the simulation is able to cover a wide range of ATM‐traffic mixes and switching architectures. Due to special simulator techniques (parallel simulation) the model can be applied within a reasonable range of load and loss probability figures. A new set of global and connection‐related performance parameters has been defined in order to evaluate the distribution of loss cases over time. The obtained results show that bursty traffic influences directly the global and connection‐related loss characteristics. The burstiness of traffic mixes results in the accumulation of losses so that losses appear in bursts with long lossfree intervals between the bursts. It is also shown that the service‐related loss probability depends on the load parameters of the service.
Performance design of an ATM node on the basis of the experience from the BLNT RACE project
Authors: Heiss Herbert , Wallmeier Eugen , Rigolio Giancarlo , Toniatti Tiziana 
Published: September 2010

AbstractThis paper contains recent results of ATM traffic studies obtained by the project partners involved in the Broadband Local Network Technology (BLNT) RACE project 1012. These studies are concerned with congestion notification methods, problems in conjunction with Peak Cell Rate control and the analysis of multi‐stage switching systems. The implications of these studies on the design and performance of an ATM node are discussed.
A new approach to sequential detection
Authors: Metzger Kurt 
Published: September 2010

AbstractThe known suboptimal sequential detection methods need a minimum‐phase signal as input for achieving good performance. As a consequence the received signal must be first transformed to minimum‐phase by an adaptive prefilter if simplified detection methods are applied. This roundabout way is avoided in a novel algorithm for sequential detection, where the metric calculation itself is fitted to the special situation of the compare‐and‐select procedure. The detection method uses two different metrics, one for comparing paths, which have merged in a common trellis‐state, the other for comparing paths which have just emerged from a common state. In this way the usual adaptive prefilter can be saved, because the proposed detector does not require a minimum‐phase signal at its input. Simulation results show excellent management of distorted and noisy signals.
An algorithm for optimal load balancing in a multiple GI/G/1 queueing system
Authors: Zhang Zhigang , Hartmann Harro L. , He Hucang , Bai Zhe 
Published: September 2010

AbstractThe issue of optimal load balancing has been raised in several important engineering fields such as the file management in a data base, the job control in a multiple processor system or the flow assignment in a packet switched data network. By modeling the subsystems as multiple GI/G/1 queues and applying known approximations and decomposition methods, the system mean response time is expressed as a function of the load allocation. To find the optimal load balancing, the convexity property is first studied with respect to the type of the arrival process of the system. We give then an efficient algorithm which finds for the convex case the global and for the non‐convex case a local minimum. Some important properties of the multiple Gl/G/1 queueing system are revealed with several numerical examples.
Multiple cochannel interference effects in a first‐order phase‐locked loop
Authors: Hasan Pavel 
Published: September 2010

AbstractThe phase error statistics of a first‐order phase‐locked loop in the presence of multiple cochannel CW interference and additive noise is derived. An accurate numerical solution based on the nonlinear theory is outlined. Approximate analytical formulae are obtained from the linear theory for low interference‐to‐signal ratios. The linear analysis shows that the phase error statistics in the linear approximation depends only on the interference‐to‐signal ratio independent of the number of interferers and the interference power distribution. Errors appeared in some of the numerical results reported by Yoon and Lindsey [1] in the single interferer case are identified and corrected. Numerical examples for N = 2, 3, and 6 interferers of equal power are given. The effect of the interference power distribution is investigated.
Decision feedback equalization of HDSL using a generalized adaptive IIR delay filter
Authors: Ghavami Mohammad , Nader‐Esfahani Said , Rupprecht Werner 
Published: September 2010

AbstractA decision feedback equalization scheme comprising of a generalized adaptive infinite impulse response delay filter in the feedback path is proposed and used for equalization of high‐rate digital subscriber loops including severe intersymbol interference and near‐end crosstalk colored noise. The feedback filter compensates the long postcursor intersymbol interference due to the high sampling rate and is composed of parallel sections having one, two or four coefficients and a delay element. The structures of the sections are determined adaptively and in a step‐by‐step procedure. Because of the parallel and, at most, two‐pole sections of the generalized adaptive infinite impulse response delay filter, the stability monitoring requires essentially no computations. To reduce the noise enhancement effect of the prefilter, an adaptive noise predictor is also used. Computer simulation results demonstrate the performance of the proposed structure compared to the conventional decision feedback equalizer with a finite impulse response feedback filter. The main advantage of the proposed system is the significant reduction in the number of coefficients and consequently the adaptation time.
Mean time to lose lock of the first‐and second‐order modified code tracking loop used in spread spectrum systems
Authors: Welti A. L. , Bernhard U. P. 
Published: September 2010

AbstractPseudonoise (PN) code tracking loops are essential in various direct‐sequence spread‐spectrum (DSSS) systems for both, communication and navigation applications. This paper shows how to optimize the so‐called modified code tracking loop (MCTL) of first‐ and second‐order by using the mean time to lose lock (MTLL) as a performance criterion. The state equation of the first‐order MCTL is related to the Smoluchowski ‐ Kramers approximation of a second‐order system described by the Langevin equation of motion. For such a specific system, the MTLL is known by the work of Kramers. In case of the second‐order type II loop (having two perfect integrators), which cannot be described by the Langevin equation, the computation of the MTLL is based on the singular perturbation method. Optimal parameters maximizing the MTLL under the constraint of Doppler effects and the channel noise are derived for both type of loops, resulting in very simple expressions that can be used immediately for a practical loop design. Measurements performed for the first‐order MCTL verify the theoretical optimal loop parameters and indicate that the time to lose lock is exponentially distributed. Monte Carlo simulations confirm also very well the theoretical results in case of a second‐order loop and hence, show that the application of the singular perturbation method yields an excellent approximation of the MTLL.
Testing methods and equipments for ATM switching nodes
Authors: Di Concetto Marco , Gabrielli Luciano , Vercellone Vinicio , Melen Riccardo 
Published: September 2010

AbstractAfter several years of theoretical studies and laboratory experiments, the ATM technique has now reached a sufficient degree of maturity that makes it ready to be experimented in the field. ATM substantially differs from traditional switching and transmission techniques for the statistical multiplexing introduced by the asynchronous technique. It turns out that the testing process is a formidable challenge for the operator, due to both the functional complexity foreseen for the B‐ISDN switching systems and to the sophisticated performance issues involved. This paper is devoted to a first assessment of the relatively unexplored problem of specifying ATM switching equipment and testing its conformance to the specification. It begins by reviewing some concepts regarding the testing of existing switching systems, then examines the peculiarities of ATM, outlines the main critical issues and their possible solution.
Cryptographic hash functions
Authors: Preneel Bart 
Published: September 2010

AbstractHash functions were introduced in cryptology in the late seventies as a tool to protect the authenticity of information. Soon it became clear that they were a very useful building block to solve other security problems in telecommunication and computer networks. This paper sketches the history of the concept, discusses the applications of hash functions, and presents the approaches that have been followed to construct hash functions. In addition, it tries to provide the information which is necessary to choose a practical hash function. An overview of practical constructions and their performance is given and some attacks are discussed. Special attention is paid to standards dealing with hash functions.
An homogeneous medical tele‐working domain supported by a new remote expert consultation conferencing service
Authors: Lymberopoulos Dimitris , Anastassopoulos George , Karatzoglou Minas , Kokkinakis George 
Published: September 2010

AbstractThis paper proposes a new multimode communication service, denoted as Remote Expert Consultation Service (REC‐Service) which determines the way group teleworking is realized among distributed entities (workstations, data bases, etc) during a conference for medical diagnosis. The REC‐Service organizes the involved operations into five different types, called Conferencing Modes (CM), where each CM yields a traffic with variable attributes and requires of the network a special quality of service. Moreover, the structure of a Broadband user‐Network Interface Unit (BNIU) is defined. BNIU statistically multiplexes the traffic of the entities working in different CMs into an Integrated Broadband Communication (IBC) network. The maximum number of entities served per BNIU and the bandwidth usability have been calculated for several operating modes by modelling the BNIU as a queueing system and by applying special quality criteria, delay demands and traffic assumptions.