bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of NMR Lineshape Anisotropy of Guest Molecules within Inclusion Complexes from Molecular Dynamics Simulations
Authors: Alavi Saman , Dornan Peter , Woo Tom K. 
Published: April 2008

AbstractNonspherical cages in inclusion compounds can result in non‐uniform motion of guest species in these cages and anisotropic lineshapes in NMR spectra of the guest. Herein, we develop a methodology to calculate lineshape anisotropy of guest species in cages based on molecular dynamics simulations of the inclusion compound. The methodology is valid for guest atoms with spin 1/2 nuclei and does not depend on the temperature and type of inclusion compound or guest species studied. As an example, the nonspherical shape of the structure I (sI) clathrate hydrate large cages leads to preferential alignment of linear CO2 molecules in directions parallel to the two hexagonal faces of the cages. The angular distribution of the CO2 guests in terms of a polar angle θ and azimuth angle ϕ and small amplitude vibrational motions in the large cage are characterized by molecular dynamics simulations at different temperatures in the stability range of the CO2 sI clathrate. The experimental 13C NMR lineshapes of CO2 guests in the large cages show a reversal of the skew between the low temperature (77 K) and the high temperature (238 K) limits of the stability of the clathrate. We determine the angular distributions of the guests in the cages by classical MD simulations of the sI clathrate and calculate the 13C NMR lineshapes over a range of temperatures. Good agreement between experimental lineshapes and calculated lineshapes is obtained. No assumptions regarding the nature of the guest motions in the cages are required.
Clean and Facile Solution Synthesis of Iron(III)‐Entrapped γ‐Alumina Nanosorbents for Arsenic Removal
Authors: Park Ho Seok , Lee Young‐Chul , Choi Bong Gill , Hong Won Hi , Yang Ji‐Won 
Published: April 2008

AbstractIron(III)‐entrapped γ‐alumina nanosorbents were prepared by an environmentally benign method using an ionothermal process based on an ionic liquid to synthesize the γ‐alumina host and a sonochemical method to entrap the iron(III) guest. The morphology of the alumina depends on the aluminum precursor used, giving aligned bundled and randomly debundled γ‐alumina nanorods as well as wormlike mesoporous alumina. In particular, the rodlike structure shows significantly greater mesoporosity than the wormlike porous γ‐alumina structure. Moreover, entrapment of iron(III) in the γ‐alumina nanosorbents with randomly debundled rodlike structures leads to the greatest AsV removal capacity and the fastest adsorption rate as compared to the other FeIII‐entrapped adsorbents, as a result of its larger surface area and pore sizes. Thus, this method provides a clean and effective route to an advanced host–guest adsorbent system for application in the removal of arsenic from drinking water.
From Biomass to a Renewable LiXC6O6 Organic Electrode for Sustainable Li‐Ion Batteries
Authors: Chen Haiyan , Armand Michel , Demailly Gilles , Dolhem Franck , Poizot Philippe , Tarascon Jean‐Marie 
Published: April 2008

AbstractLi‐ion batteries presently operate on inorganic insertion compounds. The abundance and materials life‐cycle costs of such batteries may present issues in the long term with foreseeable large‐scale applications. To address the issue of sustainability of electrode materials, a radically different approach from the conventional route has been adopted to develop new organic electrode materials. The oxocarbon salt Li2C6O6 is synthesized through potentially low‐cost processes free of toxic solvents and by enlisting the use of natural organic sources (CO2‐harvesting entities). It contains carbonyl groups as redox centres and can electrochemically react with four Li ions per formula unit. Such battery processing comes close to both sustainable and green chemistry concepts, which are not currently present in Li‐ion cell technology. The consideration of renewable resources in designing electrode materials could potentially enable the realization of green and sustainable batteries within the next decade.
High‐Surface‐Area TiO2 and TiN as Catalysts for the CC Coupling of Alcohols and Ketones
Authors: Fischer Anna , Makowski Philippe , Müller Jens‐Oliver , Antonietti Markus , Thomas Arne , Goettmann Frederic 
Published: April 2008

AbstractTo design more sustainable processes for the alkylation of ketones, the use of both atom‐ineffective leaving groups such as halides and boron as well as noble‐metal‐based catalysts should be avoided. For that purpose, high‐surface‐area titanium nitride was prepared from high‐surface‐area titanium dioxide using cyanamide as a transcription agent. The resulting nitride as well as the initial oxide proved to be effective and versatile catalysts for the alkylation of ketones with alcohols. Interestingly, the TiN catalyst yields unsaturated compounds, while the oxide‐based catalyst mainly yields saturated coupling products. As a result of its metallic properties, TiN shows a strong tendency to catalyse the dehydrogenation of alcohols, which then undergo aldol condensation with ketones. In contrast, TiO2 promotes the direct nucleophilic attack of ketones on alcohols.
Coordination Studies of a New Nonsymmetric Ditertiary Phosphane Bearing a Single Phosphaadamantane Cage
Authors: Cunningham Tom J. , Elsegood Mark R. J. , Kelly Paul F. , Smith Martin B. , Staniland Paul M. 
Published: April 2008

AbstractThe new nonsymmetric ditertiary phosphane, Ph2P(CH2)2PAd (1), was prepared in one‐step from Ph2PCH=CH2 andH‐PAd (H‐PAd = 1,3,5,7‐tetramethyl‐2,4,8‐trioxa‐6‐phosphaadamantane) by a hydrophosphination reaction using 2,2′‐azo‐bisisobutyronitrile (AIBN) as free radical initiator. The sterically encumbered phosphaadamantane cage in 1 was found to influence the coordination capabilities of this ligand. The reaction of 1 with [PdCl2(cod)] or [Pt(CH3)2(cod)] (cod = cycloocta‐1,5‐diene) gave the corresponding κ2‐P,P′‐chelate complexes cis‐[PdCl2(1)] (2) and cis‐[Pt(CH3)2(1)] (3), respectively. The dinuclear gold(I) complex [Ph2P(AuCl)(CH2)2PAd(AuCl)] (4) was prepared from 1 and 2 equiv. of [AuCl(tht)] (tht = tetrahydrothiophene). In contrast, the cleavage of the chloro‐bridged dimers {RuCl2(η6‐p‐cymene)}2 or {MCl2(η5‐Cp*)}2 (M = Rh, Ir) with 1 gave the κ1‐P‐monodentate complexes [RuCl2(η6‐p‐cymene)(1)] (5), [RhCl2(η5‐Cp*)(1)] (6) and [IrCl2(η5‐Cp*)(1)] (7), respectively, in which the ‐PAd group is non‐coordinating. Chloride abstraction from 6 (or 7) can be accomplished upon addition of Na[SbF6] to generate the cationic κ2‐P,P′‐chelate complexes 8b (and 9b). Alternatively 8a (or 9a) could be observed, as their chloride salts, by 31P{1H} NMR spectroscopy upon addition of several drops of CH3OH to CDCl3 solutions of 6 (or 7). The reaction of 5–7 with [AuCl(tht)] gave the dinuclear complexes [κ2‐P,P′‐μ‐RuCl2(η6‐p‐cymene){Ph2P(CH2)2PAd(AuCl)}] (10), [κ2‐P,P′‐μ‐RhCl2(η5‐Cp*){Ph2P(CH2)2PAd(AuCl)}] (11) and [κ2‐P,P′‐μ‐IrCl2(η5‐Cp*){Ph2P(CH2)2PAd(AuCl)}] (12). Reaction of two equiv. of 5 with the labile precursors [PdCl2(CH3CN)2] or [PtCl2(PhCN)2] gave instead the novel trinuclear Ru2Pd and Ru2Pt complexes trans‐[{κ2‐P,P′‐μ‐RuCl2(η6‐p‐cymene){Ph2P(CH2)2PAd}}2PdCl2] (13) and trans‐[{κ2‐P,P′‐μ‐RuCl2(η6‐p‐cymene){Ph2P(CH2)2PAd}}2PtCl2] (14), respectively. All new compounds have been fully characterised by spectroscopic and analytical methods. Furthermore the structures of 3·CHCl3, 4, 5, 7·CHCl3, 10·CH2Cl2·0.5C2H10O and 13·2CH2Cl2 have been elucidated by single‐crystal X‐ray crystallography. The X‐ray structures of 10·CH2Cl2·0.5C4H10O and 13·2CH2Cl2 demonstrate how nonsymmetric ditertiary phosphane complexes bearing one pendant phosphaadamantane moiety can be used as metalloligands in the controlled syntheses of novel bi‐ and trimetallic complexes.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Syntheses, Structures and Photophysical Properties of New Heterodinuclear Cd–Ln Coordination Complexes (Ln = Sm, Eu, Tb, Nd, Ho, Er)
Authors: Chi Yu‐Xian , Niu Shu‐Yun , Wang Zhao‐Long , Jin Jing 
Published: April 2008

AbstractSix novel heterodinuclear d–f coordination complexes [LnCd(C8H7O3)5(phen)(H2O)] (Ln = Sm 1, Eu 2, Tb 3, Nd 4, Ho 5, Er 6; C8H7O3 = 4‐methoxybenzoato; phen = 1,10‐phenanthroline) were synthesized by the hydrothermal method, and their structures were studied by single‐crystal X‐ray diffraction. The IR and UV/Vis/NIR absorption spectra and the luminescence spectra of the six complexes were determined at room temperature. They have the same molecular structure, and two neighboring molecules are connected by hydrogen bonds or by a Ln···O weak interaction to form dimer crystals. In the visible region, the emission spectra of complexes 1–3 show the intense characteristic bands of the corresponding LnIII ions, which are mainly attributed to the efficient energy transfer from the d block to the f block, that is, to the good sensitization of the d block. Moreover, in the Cd–Ln coordination complexes, the Cd···Ln separation is very small, and the 4d orbitals of the CdII ion may influence the 4f orbitals of the LnIII ion, which probably causes some of the f levels of the LnIII ion to be adjusted, and this effect can be observed in the shifts or splittings of the absorption bands in the UV/Vis/NIR spectra of the complexes. Especially in complexes 4–6, some energy levels of the LnIII ions have shifts or splittings, hence the corresponding emission bands exhibit shifts or splittings in the NIR region. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Effect of various extraction conditions on the phenolic contents of pomegranate seed oil
Authors: Abbasi Hajar , Rezaei Karamatollah , Emamdjomeh Zahra , Mousavi Seyyed M. Ebrahimzadeh 
Published: April 2008

AbstractPomegranate seeds are byproducts of the pomegranate juice industry. Because of the presence of large amounts of certain pharmaceutical and nutraceutical components in the seeds, a proper extraction method to obtain these components is highly demanded in the food industry. In this study, the effect of different extraction methods on the total phenolic contents of the oil extracted from pomegranate seeds of the Malas variety from Shahreza, Iran, was investigated. Four different extraction methods including normal stirring, Soxhlet, microwave irradiation and ultrasonic irradiation using two types of organic solvents as well as a supercritical fluid extraction (SFE) method using CO2 as solvent were applied. The different organic solvents of this study did not indicate any significant differences in the total phenolic contents of the extracted oils, but the extracted oils from the various conditions of SFE indicated wide changes in the amount of phenolic compounds (7.8–72.1 mg/g). The total phenolic content of the extracted oil from one of the SFE runs was several times greater than those in the extracted oils using organic solvents.
Microwave‐assisted hydrodistillation of essential oil from Zataria multiflora Boiss
Authors: Golmakani Mohammad‐Taghi , Rezaei Karamatollah 
Published: April 2008

AbstractMicrowave‐assisted hydrodistillation (MAHD) has recently gained attention for the extraction of essential oils. A concern with the use of MAHD is the possibility of sample deterioration during the extended exposure to microwave irradiation. In this study, MAHD was applied as a new and green technology for the extraction of essential oil from Zataria multiflora Boiss. (Shirazi thyme) aerial parts. Superior results were obtained with the proposed method in terms of extraction time [1 h vs. 4 h in hydrodistillation (HD)] for an essential oil recovery of 3.66 and 3.44%, respectively. Images obtained from thyme leaves using scanning electron microscopy indicated a sudden eruption of essential oil glands undergoing MAHD. GC‐MS analysis of the essential oils did not indicate any new or missing compounds in the essential oil obtained by MAHD in comparison with that by HD. Therefore, a microwave oven can be safely used for the extraction of essential oil from Shirazi thyme.
A multichannel electrophoresis microchip platform for rapid chiral selector screening
Authors: Gao Yan , Luo Yong , Qin Jianhua , Lin Bingcheng 
Published: April 2008

AbstractThis study presents a four‐channel electrophoresis chip platform, featuring double‐cross hydrostatic sample injection, for rapid chiral selector screening. This platform needs only five electrodes to drive microchip electrophoresis in four separate channels for screening four chiral selectors at a time. To demonstrate the performance of this screening platform, eight neutral CDs and their derivatives as chiral selectors were screened towards two FITC‐labeled chiral compounds. The screening could be accomplished in less than 2 min. Dimethyl‐β‐CD and hydroxypropyl‐α‐CD was demonstrated to be the appropriate selectors for FITC‐norfenefrine and FITC‐baclofen, respectively. The established platform is easy to operate and suitable for rapid screening process, which is expected to be a potential platform for high‐throughput screening of chiral selectors.
Analytical optimization of nanocomposite surface‐enhanced Raman spectroscopy/scattering detection in microfluidic separation devices
Authors: Connatser R. Maggie , Cochran Malcolm , Harrison Robert J. , Sepaniak Michael J. 
Published: April 2008

AbstractAdding vibrational spectroscopies to the arsenal of detection modes for microfluidics (μfluidics) offers benefits afforded by structurally descriptive identification of separated electrophoretic bands. We have previously applied surface‐enhanced Raman spectroscopy (SERS) detection with nanocomposite metal–elastomer substrates as a detection mode in μfluidic channels. To create these μfluidic‐SERS devices, silver‐PDMS substrate regions are integrated into the architecture of a separation chip fabricated from PDMS or glass. Herein, we investigate analytical figures of merit for integrated μfluidic‐SERS devices by implementing improvements in fluidic and SERS substrate fabrication as well as data collection strategies. Improvements are achieved by chemical modification of the PDMS channel, increasing effective detection efficiency by minimizing analyte partitioning into nonsensing walls rendering more analyte available to the metallized cover slide of channels and also by uniquely fabricating deep channels that have larger volume to SERS surface area ratios than conventional channels. A method is developed to exploit the inherent concentration profile of analyte material within an electrophoretic band in order to extend the linear dynamic range of detection on the SERS nanostructured surface. This is accomplished by spatially interrogating the Gaussian concentration profile of said bands. The subtleties of this technique give insight into the analytical utility of SERS detection in general. Finally, SERS substrates uniquely created via electron beam lithography with controllable morphologies are integrated into μfluidic‐SERS devices to prove feasibility of such a coupling for future work. A separation of endocrine disrupting chemicals in a hybrid SERS nanocomposite‐glass device is the capstone of this work.
Electrokinetic supercharging for highly efficient peptide preconcentration in capillary zone electrophoresis
Authors: Busnel Jean‐Marc , Lion Niels , Girault Hubert H. 
Published: April 2008

AbstractElectrokinetic supercharging has been integrated in CZE for the development of a highly sensitive methodology for protein tryptic digest analysis. A careful choice of the experimental conditions led to sensitivity enhancement factors between 1000 and 10 000 whilst maintaining a satisfactory resolution. Peptides in the low nanomolar concentration range have been detected despite the use of the poorly sensitive UV absorbance detection mode. The buffer system used in this study is fully suitable for coupling CE to MS.
Sulfonated molecules that bind a partially structured species of β2‐microglobulin also influence refolding and fibrillogenesis
Authors: Carazzone Chiara , Colombo Raffaella , Quaglia Milena , Mangione Palma , Raimondi Sara , Giorgetti Sofia , Caccialanza Gabriele , Bellotti Vittorio , De Lorenzi Ersilia 
Published: April 2008

AbstractHuman β2‐microglobulin (β2‐m) is a small amyloidogenic protein responsible for dialysis‐related amyloidosis, which represents a severe complication of long‐term hemodialysis. A therapeutic approach for this amyloidosis could be based on the stabilization of β2‐m through the binding to a small molecule, to possibly inhibit protein misfolding and amyloid fibril formation. The search of a strong ligand of this protein is extremely challenging: by using CE in affinity and refolding experiments we study the effect that previously selected sulfonated molecules have on the equilibrium between the native form and an ensemble of conformers populating the slow phase of β2‐m folding. These data are correlated with the effect that the same molecules exert on in vitro fibrillogenesis experiments.
COWAR: A CAPE OPEN software module for the evaluation of process sustainability
Authors: Fermeglia Maurizio , Longo Gennaro , Toma Letitia 
Published: April 2008

AbstractThe sustainability of a chemical process can be estimated using qualitative and quantitative indicators. Quantitative indicators, such as potential environmental impact (PEI) indexes, are essential for evaluating the environmental impact of a chemical process and for choosing the best design among available alternatives. Waste Reduction (WAR) Algorithm, used to calculate the PEI indexes, is implemented using a standard methodology, CAPE OPEN (CO). Such development leads to COWAR, a software module for the evaluation of process sustainability. Details regarding the COWAR development and function are presented in this work. Finally, a representative chemical process is presented to demonstrate the software applicability. © 2008 American Institute of Chemical Engineers Environ Prog, 2008
Efficiency of single‐stock futures: An intraday analysis
Authors: Fung Joseph K.W. , Tse Yiuman 
Published: April 2008

AbstractUsing intraday bid–ask quotes of single‐stock futures (SSFs) contracts and the underlying stocks, the pricing and informational efficiency of SSF traded on the Hong Kong Exchange are examined. Both the SSFs and the stocks are traded on electronic platforms. The market microstructure and the data obviate the problems of stale and non‐executable prices as well as uncertain bid–ask bounce of the thinly traded futures contracts. Nominal price comparisons show that more than 80% of SSF quotes are inferior to stock quotes. More than 99% of the observed futures spreads are above one stock tick compared with only 2% of those for stocks. After adjusting for the cost‐of‐carry, however, SSFs are fairly priced. Given higher stock trading costs, non‐members should even find the futures attractively priced. Thus, the absence of competitive market maker does not bias prices so as to discourage trading. SSF quotes also account for one‐third of price discovery despite their low volume. © 2008 Wiley Periodicals, Inc. Jrl Fut Mark 28:518–536, 2008
Pricing European Asian options with skewness and kurtosis in the underlying distribution
Authors: Lo Keng‐Hsin , Wang Kehluh , Hsu Ming‐Feng 
Published: April 2008

AbstractNumerical valuation model is extended for European Asian options while considering the higher moments of the underlying asset return distribution. The Edgeworth binomial lattice is applied and the lower and upper bounds of the option value are calculated. That the error bound in pricing Asian options from the Edgeworth binomial model is smaller than the error bound model by Chalasani et al. is shown. The approach is used to price the average rate currency option with different skewness and kurtosis. The numerical results show that this approach can effectively deal with the higher moments of the underlying distribution and provide better estimates of option value compared with various studies in literature. © 2008 Wiley Periodicals, Inc. Jrl Fut Mark 28:598–616, 2008
Precipitation water storage capacity in a temperate mixed oak–beech canopy
Authors: André Frédéric , Jonard Mathieu , Ponette Quentin 
Published: April 2008

AbstractThe storage capacity of a temperate mixed oak–beech stand was investigated as a function of stand density and species composition. Measurements were performed in selected zones delimited by three neighbouring trees. Three independent approaches were compared: (i) a spraying laboratory experiment to estimate the water storage on foliage before and after dripping; (ii) a mechanistic model describing rainfall partitioning within the forest canopy and providing estimates of foliage storage capacities; and (iii) linear regression analyses to evaluate the canopy (foliage + branches) storage capacity using the relationship between throughfall and rainfall. Good agreement was generally observed between the laboratory experiment and the mechanistic model estimates, while estimations from the regression method tended to exceed those from the other approaches. Storage capacity estimates ranged from 0·22 mm to 0·80 mm for pure oak zones, from 0·24 mm to 1·12 mm for mixed zones and from 0·53 mm to 1·17 mm for pure beech zones. The increase of storage capacity with increasing proportion of beech in the canopy resulted from higher beech LAI compared with oak. Similarly, for mixed and pure beech canopies, storage capacity was higher for high density zones than for low density zones as a result of the increase in LAI with increasing local basal area; in contrast, for pure oak, the storage capacity was not related to basal area because of the lower shade‐tolerance of this species compared with beech. Copyright © 2008 John Wiley & Sons, Ltd.
Ion enrichment of snowmelt runoff water caused by basal ice formation
Authors: Lilbæk Gro , Pomeroy John W. 
Published: April 2008

AbstractOnce meltwater reaches the base of a snowpack it can infiltrate the underlying stratum, runoff, or refreeze and form a basal ice layer. Basal ice formation is most common early in melt over saturated or very cold frozen soils. Initial meltwater becomes enriched in ion concentrations compared to the parent snow due to ion fractionation during thaw and percolation through the snowpack. If ion exclusion occurs during basal ice formation, further enrichment of initial runoff water ion concentrations might occur. The influence of basal ice formation on runoff water chemistry was examined by comparing ion concentrations in runoff water that had sustained basal ice contact, to meltwater before basal ice contact. A series of experiments, involving melting a snowpack in a large insulated box over a cold impermeable substrate in a temperature‐controlled room, were carried out. A cooling system at the chemically inert base ensured formation of basal ice during snowmelt. Meltwater samples were collected throughout melt from within the snowpack using an extraction tube; runoff water was collected at the base. All samples were analysed for major anions and cations. Results showed that formation of basal ice layers can sometimes enrich the initial runoff water compared to meltwater before basal ice contact. Ion concentrations in basal ice contact runoff water were up to sixteen times greater than those in no‐contact meltwater; however, on average, basal ice contact runoff water showed 1·5 times the ion concentrations of the no‐contact meltwater. Enrichment was greatest with the rapid formation of a thick basal ice layer. The implications are that basal ice formation alters both meltwater ion pathway and concentration. When no basal ice is present, enhanced infiltration of meltwater ion load can cause relatively dilute runoff water. When basal ice is present all meltwater runs off and further ion‐concentration enrichment occurs. Copyright © 2008 John Wiley & Sons, Ltd.