bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiphase flow at the edge of a steam chamber
Authors: Sharma Jyotsna , Gates Ian D. 
Published: April 2010

AbstractThe use of steam‐assisted gravity drainage (SAGD) to recover bitumen from Athabasca deposits in Alberta has been growing. Butler [Butler, J. Can. Pet. Tech. 1985;24:42–51] derived a simple theory to calculate the production rate of oil during SAGD in an ideal reservoir. This simple and useful theory made several assumptions about the properties of the reservoir and operating conditions of the process. The theory also assumed that the highest mobility oil is at the edge of the steam chamber and that the oil phase velocity is highest at the chamber edge and reduces with distance into the oil sand. This research examines flow conditions at the edge of the steam chamber. Specifically, a new theory is derived that takes into account the impact of oil saturation and relative permeability on the oil mobility profile at the edge of a steam chamber. It is shown that the flow behaviour at the edge of a steam chamber is more complex and is not fully represented by Butler's theory. Contrary to Butler's theory, the oil mobility has its maximum some distance away from the edge of the steam chamber. The results reveal that the higher the thermal diffusivity of the oil sand, the deeper the location where the oil phase velocity is maximum. The developed model has been validated against published experimental and field data.
Modelling and simulation of an oxychlorination reactor in a fluidized bed
Authors: Moreira J. C. S. , Pires C. A. M. 
Published: April 2010

AbstractTaking 1,2‐dichloroethane from the oxychlorination reaction is a commercially very important process due to the large application of the 1,2‐dichloroethane in the chemical industry of PVC production. This work presents the modeling and simulation of an oxychlorination reactor with a fluidized bed. The pseudo‐homogeneous model with one‐dimensional flow in steady state was applied based on the theory of fluidized bed in two phases. It allows the sensitivity analysis of the operational and project parameters of the reactor. The ordinary differential equations system that represents the mathematical model of the reactor was solved through the application of the numerical method of Newton–Raphson's. The results obtained have proved that the developed model represents the system suitably, in spite of the one‐dimensional model. The effect of different parameters was investigated through the sensitivity analysis, and the results show that the parameters that have the largest influence on the reactor performances are: fluidized bed height, bubble diameter, residence time, cupric chloride weight in the catalyst, and emulsion phase temperature.
Investigation of the local specific energy dissipation rates in a jet‐zone loop reactor for halogenation of ketones
Authors: Wiedemann Mathias , Schlüter Michael , Räbiger Norbert 
Published: April 2010

AbstractWithin the framework of process intensification there is a growing demand for novel reactor technologies. For the improvement of halogenation of ketones a jet‐zone loop reactor (JZR) is used, which leads to an enormous increase in yield and selectivity compared to stirred vessels (Kutschera et al., 2008). This JZR is a special jet loop reactor with high specific mass transfer performance and good macromixing behaviour. It is obvious that there is direct relation between the reaction and the hydrodynamics in the reactor. Despite several aspects of hydrodynamics in jet loop reactors have been investigated, the essential flow characteristics behind a two‐component jet are not sufficiently understood. In these investigations, the flow field in the jet zone of the JZR was analysed by 2D particle image velocimetry (PIV) and the kinetic energy dissipation rate ε was determined from the spatial gradients of the fluctuating velocity.
Comparison of Effects of Simvastatin Versus Atorvastatin on Oxidative Stress in Patients With Coronary Heart Disease
Authors: Li Jia , Sun Yan‐Ming , Wang Lan‐Feng , Li Zhu‐Qin , Pan Wei , Cao Hong‐Yan 
Published: April 2010

AbstractBackgroundHMG‐CoA reductase inhibitors (statins) have antiatherogenic effects beyond their cholesterol‐lowing effect. Whether atorvastatin has a stronger antioxidant effect than other statins is uncertain.HypothesisTo determine the effects of simvastatin and atorvastatin on markers of oxidative stress in patients with coronary heart disease (CHD).MethodsThis study was comprised of 164 patients with CHD and a control population of 122 healthy subjects. The patients with CHD were divided into 2 groups and treated with either simvastatin 20 mg/day or atorvastatin 10 mg/day. The markers of oxidative stress were measured before and after 12 weeks of treatment.ResultsThe effects of atorvastatin on reducing oxidative stress were significantly greater compared with those of simvastatin (P < 0.05). The changes in the markers of oxidative stress did not correlate with the changes in the plasma lipid profile (P > 0.05).ConclusionsThis study suggests that atorvastatin reduces oxidative stress more effectively than simvastatin. Copyright © 2010 Wiley Periodicals, Inc.
Prevalence and Prognosis of Chronic Obstructive Pulmonary Disease Among 8167 Middle Eastern Patients With Acute Coronary Syndrome
Authors: Hadi Hadi A. R. , Zubaid Mohammed , Mahmeed Wael Al , El‐Menyar Ayman A. , Ridha Mustafa , Alsheikh‐Ali Alawi A. , Singh Rajivir , Assad Nidal , Habib Khalid Al , Suwaidi Jassim Al 
Published: April 2010

AbstractBackgroundThe purpose of this study was to report the prevalence and the significance of clinically recognized chronic obstructive pulmonary disease (COPD) during acute coronary syndrome (ACS).HypothesisCOPD in patients with ACS is associated with worse outcome.MethodsData were derived from a prospective, multicenter, multinational study of 8167 consecutive patients hospitalized with ACS from February to June 2007 in 6 Middle Eastern countries. Data were analyzed according to the presence or absence of COPD. Demographic, management, and in‐hospital outcomes were compared.ResultsThe prevalence of COPD was 5.3%. When compared with non‐COPD patients, COPD patients were older and more likely to have diabetes, hypertension, and dyslipidemia. Atypical presentations were more common in COPD patients (P = 0.001). COPD patients were less likely to be treated with thrombolytic therapy (P = 0.001), β‐blockers (P = 0.001), and glycoprotein IIb/IIIa inhibitors, and more likely to receive angiotensin‐converting enzyme (ACE) inhibitors. Although there was no difference in in‐hospital mortality between the 2 groups, patients with COPD were more likely to have heart failure (P = 0.001). Despite the fact that COPD patients with ST‐segment elevation myocardial infarction were less likely to receive thrombolytic therapy, they suffered more bleeding complications (2.8% vs 1%, P = 0.04), resulting in prolonged hospitalization. COPD was not an independent predictor of increased in‐hospital mortality.ConclusionsIn this large cohort of patients with ACS, the prevalence of COPD was 5·3%. Atypical presentation is common among COPD patients, and this may result in delayed therapy. ACS in COPD patients was associated with higher risk of heart failure and major bleeding complications without increased risk of in‐hospital mortality. Copyright © 2010 Wiley Periodicals, Inc.
Synthesis and in vitro and in vivo Antifungal Activity of the Hydroxy Metabolites of Saperconazole
Authors: Meerpoel Lieven , Heeres Jan , Backx Leo J. J. , Van der Veken Louis J. E. , Hendrickx Rob , Corens David , De Groot Alex , Leurs Stef , Van der Eycken Luc , Weerts Johan , Luyts Paul , Van Gerven Frans , Woestenborghs Filip A. A. , Van Breda Andre , Oris Michel , van Dorsselaer Pascal , Willemsens Gustaaf H. M. , Bellens Danny , Marichal Patrick J. M. G. , Vanden Bossche Hugo F. , Odds Frank C. 
Published: April 2010

AbstractHerein we describe the scalable diastereoselective and enantioselective syntheses of eight enantiomers of hydroxy metabolites of saperconazole. The in vitro antifungal activity of the eight stereoisomers (compounds1–8) was compared against a broad panel ofCandida spp. (n=93),Aspergillus spp. (n=10),Cryptococcus spp. (n=19), and dermatophytes (n=27). The four 2Sisomers1–4of the new agent were generally slightly more active than the four 2Risomers5–8. All eight isomers were tested in a model of experimentalA. fumigatusinfection in guinea pigs by intravenous inoculation of the fungal conidia. Treatment doses were 1.25 mg kg−1and 2.5 mg kg−1per day. Infection severity was measured in terms of mean survival time (MST) after infection and mean tissue burdens in brain, liver, spleen, and kidney at postmortem examination. Among the eight isomers, the 2Sdiastereomers1–4showed a generally higher level of activity than the 2Rdiastereomers5–8, revealing compounds1and4as the most potent overall in eradicating tissue burden and MST. Compared with reference compounds itraconazole and saperconazole, the hydroxy isomers1–8are less potent inhibitors of the growth ofA. fumigatusin vitro and of ergosterol biosynthesis in bothA. fumigatusandC. albicans.
Size‐Dependent Binding Energies of Methane to Small Gold Clusters
Authors: Lang Sandra M. , Bernhardt Thorsten M. , Barnett Robert N. , Landman Uzi 
Published: April 2010

AbstractThe reactions of small gold cluster cations Aux+ (x=2–6) with CH4 were studied by joint gas‐phase kinetics and first‐principles density functional theory calculations. The experimentally obtained temperature‐dependent low pressure rate constants were analyzed by employing the Lindemann energy transfer model for association reactions in conjunction with statistical RRKM theory. In this way cluster‐size‐dependent binding energies of methane to the gold cluster cations were determined from the experimental data for two different transition‐state models. The experimental binding energies obtained by employing a “loose” transition‐state model are in good agreement with the theoretical values at the optimal adsorption geometries, while a “tight” transition‐state model clearly gives a lower limit for the binding energies. Additionally, Kohn–Sham molecular orbitals of AuxCH4+ are presented to gain detailed insight into the cluster–methane bonding mechanism.
The Diversity of Electron‐Transport Behaviors of Molecular Junctions: Correlation with the Electron‐Transport Pathway
Authors: Liu Hongmei , Yu Cui , Gao Nengyue , Zhao Jianwei 
Published: April 2010

AbstractWe report the electron‐transport behaviors of a number of molecular junctions composed of π‐conjugated molecular wires. From calculations performed by using density functional theory (DFT) combined with the non‐equilibrium Green’s function (NEGF) method, we found that the length–conductivity relations are diverse, depending on the particular molecular structures. The results reveal that the conductance–length dependence follows an exponential law for many conjugated molecules with a single channel, such as oligothiophene, oligopyrrole and oligophenylene. Therefore, a quantitative relation between the energy gap (Eg)∞ of the molecular wire and the attenuation factor β can be defined. However, when the molecular wires have multichannels, the decay of conductance does not follow the exponential relation. For example, the conductance of porphyrin‐based oligomers and fused thiophene decays almost linearly. The diversity of electron‐transport behaviors of molecular junctions is directly dominated by the electron‐transport pathway.
Liquid‐Phase Chemical Hydrogen Storage: Catalytic Hydrogen Generation under Ambient Conditions
Authors: Jiang Hai‐Long , Singh Sanjay Kumar , Yan Jun‐Min , Zhang Xin‐Bo , Xu Qiang 
Published: April 2010

AbstractThere is a demand for a sufficient and sustainable energy supply. Hence, the search for applicable hydrogen storage materials is extremely important owing to the diversified merits of hydrogen energy. Lithium and sodium borohydride, ammonia borane, hydrazine, and formic acid have been extensively investigated as promising hydrogen storage materials based on their relatively high hydrogen content. Significant advances, such as hydrogen generation temperatures and reaction kinetics, have been made in the catalytic hydrolysis of aqueous lithium and sodium borohydride and ammonia borane as well as in the catalytic decomposition of hydrous hydrazine and formic acid. In this Minireview we briefly survey the research progresses in catalytic hydrogen generation from these liquid‐phase chemical hydrogen storage materials.
Laser excitation power and the flow cytometric resolution of complex karyotypes
Authors: Ng Bee L. , Carter Nigel P. 
Published: April 2010

AbstractThe analytical resolution of individual chromosome peaks in the flow karyotype of cell lines is dependent on sample preparation and the detection sensitivity of the flow cytometer. We have investigated the effect of laser power on the resolution of chromosome peaks in cell lines with complex karyotypes. Chromosomes were prepared from a human gastric cancer cell line and a cell line from a patient with an abnormal phenotype using a modified polyamine isolation buffer. The stained chromosome suspensions were analyzed on a MoFlo sorter (Beckman Coulter) equipped with two water‐cooled lasers (Coherent). A bivariate flow karyotype was obtained from each of the cell lines at various laser power settings and compared to a karyotype generated using laser power settings of 300 mW. The best separation of chromosome peaks was obtained with laser powers of 300 mW. This study demonstrates the requirement for high‐laser powers for the accurate detection and purification of chromosomes, particularly from complex karyotypes, using a conventional flow cytometer. © 2010 International Society for Advancement of Cytometry
MS‐TOF Study of the Formation of Thiolato‐Bridged Rhodium Oligomers
Authors: Boudreau Josée , Grenier‐Desbiens Jérôme , Fontaine Frédéric‐Georges 
Published: April 2010

AbstractThe complex [Cp*Rh(μ‐SPh)3RhCp*]Cl was used as a starting material to synthesize various oligomeric materials of the general formula [Cp*Rh(μ‐SPh)x(μ‐Cl)3–x{Rh(μ‐SPh)3}nRhCp*] (x = 1 to 3; n = 1 to 4), which are formally formed by insertion of nRh(SPh)3 units into one μ‐Rh–SPh bond. The insertion of Ir(SPh)3 was also observed to generate theheterotrimetallic species. All complexes were observed by using HRMS‐TOF and [Cp*Rh(μ‐SPh)3Rh(μ‐SPh)3RhCp*]Cl, [3+]Cl, was characterized by using X‐ray crystallography.
A Bismuth‐Stabilized Metal‐Rich Telluride Lu9Bi≈1.0Te≈1.0 – Synthesis and Characterization
Authors: Gupta Shalabh , Maggard Paul A. , Corbett John D. 
Published: April 2010

AbstractSynthetic reactions aimed at bismuth incorporation into rare‐earth‐metal‐rich tellurides yielded Lu9Bi≈1.00Te≈1.00 over a small range of compositions, but no analogues with Gd, Tb, Er, or Y. A single‐crystal X‐ray diffraction analysis gave the composition Lu9Bi0.99(3)Te1.01 in the acentric orthorhombic space group Cmc21 at ambient temperature. This is isostructural with the re‐refined Sc9Te2 earlier reported in a monoclinic Cc structure. Lu9Bi≈1.00Te≈1.00 represents the first ternary compound in this structure type and the third lutetium‐richest compound after Lu8Te and Lu7Te. The structure contains 3 × 3 columns of Lu in the form of condensed distorted trans‐edge‐sharing octahedral chains along a. The Te and Bi anions lie within tricapped trigonal prisms of Lu. Generally shorter Lu–Lu interactions lie in the interior of 3 × 3 metal columns compared with those on the periphery for which fewer Lu–Lu interactions and polar covalent bonding with neighboring tellurium weaken Lu–Lu bonding. Limiting Lu–Lu distances around 3.18 Å are by far the shortest among reduced lutetium tellurides. LMTO‐type ab initio electronic structure calculations reveal a metallic nature and show that strong polar bonding of Lu to both the more electronegative Bi and Te leaves Lu relatively oxidized, many 5d states falling above the Fermi level. Stronger Lu–Lu bonding within the metal columns is also indicated by their larger individual Hamilton populations. The isostructural Lu9SbTe and Sc9BiTe were also shown to exist according to powder data.
An Efficient Iron‐Catalyzed Carbon–Carbon Single‐Bond Cleavage via Retro‐Claisen Condensation: A Mild and Convenient Approach to Synthesize a Variety of Esters or Ketones
Authors: Biswas Srijit , Maiti Sukhendu , Jana Umasish 
Published: April 2010

AbstractAn efficient iron‐salt‐catalyzed carbon–carbon bond cleavage occurring through a retro‐Claisen condensation reaction has been developed. The reaction is useful for the synthesis of a variety of esters or ketones under mild conditions. This method works under solvent‐free conditions without the need of an inert atmosphere. This protocol is also applicable for the one‐pot syntheses of ketones through tandem carbon–carbon bond formation (substitution or Michael) followed by a retro‐Claisen reaction. However, for Michael adducts, ring annulation takes place subsequently. Notably, this method is very simple, convenient, high yielding, and only a catalytic (5 to 10 mol‐%) amount of Fe(OTf)3 is needed.
Asymmetric Total Synthesis of (+)‐6‐epi‐Castanospermine by the Stereoselective Formation of a syn,anti Acetylenic 2‐Amino‐1,3‐diol Stereotriad
Authors: Louvel Julien , Botuha Candice , Chemla Fabrice , Demont Emmanuel , Ferreira Franck , Pérez‐Luna Alejandro 
Published: April 2010

AbstractThe asymmetric total synthesis of (+)‐6‐epi‐castanospermine (1) is described herein. In this synthesis the diastereoselective addition of a racemic allenylzinc reagent to an enantiopure α‐alkoxy‐tert‐butylsulfinylimine is the key step and is followed by the formation of a piperidine ring by ring‐closing metathesis and subsequent syn‐dihydroxylation of an alkene.
Ionic Liquid as an Alternative Greener Sensing Medium for the Chemical Warfare Agent
Authors: Singh Virendra V. , Boopathi M. , Ganesan K. , Singh Beer , Vijayaraghavan R. 
Published: April 2010

AbstractGreener electrochemical detection method developed for chemical warfare agent (CWA) nitrogen mustard‐2 (NM‐2) using room temperature ionic liquid (RTIL). The diffusion coefficient calculated for NM‐2 in acetonitrile and RTIL was 1.57×10−4 cm2/s and 1.82×10−10 cm2/s, respectively. NM‐2 addition to RTIL enhanced RTIL conductivity. Moreover, heterogeneous rate constant (0.192 s−1), transfer coefficient (0.231) and the number of electron involved (1.0) were deduced for NM‐2 in RTIL. The calibration plot showed linearity between 2.94×10−5 and 1.17×10−3 M with detection limit 1.47 ×10−5 M (S/N=3). The large number of available RTIL can be used for greener detection of toxic CWAs.
Tris(2,2′‐bipyridyl)ruthenium(II) Electrogenerated Chemiluminescence Sensor Based on Platinized Carbon Nanotube–Zirconia–Nafion Composite Films
Authors: Yoon Sook Hyun , Han Jee Hoon , Kim Byung Kun , Choi Han Nim , Lee Won‐Yong 
Published: April 2010

AbstractMesoporous films of platinized carbon nanotube–zirconia–Nafion composite have been used for the immobilization of tris(2,2′‐bipyridyl)ruthenium (II) (Ru(bpy)32+) on an electrode surface to yield a solid‐state electrogenerated chemiluminescence (ECL) sensor. The composite films of Pt–CNT–zirconia–Nafion exhibit much larger pore diameter (3.55 nm) than that of Nafion (2.82 nm) and thus leading to much larger ECL response for tripropylamine (TPA) because of the fast diffusion of the analyte within the films. Due to the conducting and electrocatalytic features of CNTs and Pt nanoparticles, their incorporation into the zirconia–Nafion composite films resulted in the decreased electron transfer resistance within the films. The present ECL sensor based on the Pt–CNT–zirconia–Nafion gave a linear response (R2=0.999) for TPA concentration from 3.0 nM to 1.0 mM with a remarkable detection limit (S/N=3) of 1.0 nM, which is much lower compared to those obtained with the ECL sensors based on other types of sol‐gel ceramic–Nafion composite films such as silica–Nafion and titania–Nafion.
A Comparative Study of Modifying Gold and Carbon Electrode with 4‐Sulfophenyl Diazonium Salt
Authors: Gui Alicia L. , Liu Guozhen , Chockalingam Muthukumar , Le Saux Guillaume , Harper Jason B. , Gooding J. Justin 
Published: April 2010

AbstractA comparison of the reductive adsorption behavior of 4‐sulfophenyl diazonium salt and subsequent electrochemical reactivity on gold relative to carbon was studied with some significant differences observed. The ability of the 4‐sulfophenyl layer adsorbed onto gold to block access of the redox probe ferricyanide to the underlying electrodes, as determined via cyclic voltammetry was inferior to the same layers formed on glassy carbon electrodes thus indicating a more open, porous layer formed on gold. More significantly, the 4‐sulfophenyl layers are shown to be far less electrochemically stable on gold than on glassy carbon. Electrochemical and X‐ray photoelectron spectroscopy (XPS) evidence suggests the instability is due to cleavage of the bond between sulfonate functional group and phenyl ring. These results provide further evidence that although aryl diazonium salt layers are relatively stable on gold surfaces compared with alkanethiol based self‐assembled monolayer (SAMs), the stability is not as high as is observed on carbon.
Transforming the distribution of OFDM signals for peak‐to‐average power ratio reduction
Authors: Zhu Xiaodong , Zhu Guangxi , Lin Pei 
Published: April 2010

AbstractLarge peak‐to‐average power ratio (PAPR) is the main drawback of orthogonal frequency division multiplexing (OFDM) systems. In this paper, a novel nonlinear scheme is proposed to reduce the PAPR. This scheme transforms the amplitude of original OFDM signals from Rayleigh distribution into beta distribution. Moreover, given different parameters, this scheme has different transformation expressions. It is demonstrated that the well‐known companding schemes based on exponential function and error function are actually the special cases of the proposed scheme. Further, we derive another simpler expression of the proposed scheme. Simulation results show that the new transformation can achieve a better tradeoff between PAPR reduction and bit‐error rate (BER) performance than the exponential function and error function companding schemes. Copyright © 2010 John Wiley & Sons, Ltd.
Selective mapping for reduced complexity turbo channel estimation operating on highly time and frequency selective channels
Authors: Châabouni Sihem , Siala Mohamed , Sellami Noura 
Published: April 2010

AbstractIn this paper, we consider a time division multiple access (TDMA) transmission of coded symbols over a time and frequency selective channel. At the receiver, a turbo‐detector composed of a maximuma posteriori(MAP) equaliser and a MAP decoder is used. We give the expression of the MAP iterative burst‐by‐burst channel estimation algorithm using the Expectation‐Maximisation (EM) algorithm. Since the obtained algorithm is complex, we propose to simplify it by neglecting the inter‐symbol interference (ISI) term. In order to reduce the error caused by this simplification, we propose to use a candidate precoder at the transmitter chosen among a given set of precoders such that the selected precoded sequence leads to the minimum mean square value of the ISI neglected term. Simulations show that the performance of the approximate algorithm with precoding are almost similar to the performance of the exact algorithm. Copyright © 2010 John Wiley & Sons, Ltd.