bluuebunny/crossref_metadata_2025_split huggingface dataset:
ChemInform Abstract: Non‐Metallocene Rare‐Earth Organometallic Derivatives: Synthesis, Structure and Application in the Catalysis of Transformations of Unsaturated Substrates
Authors: Trifonov A. A. 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Preparation and Characterization of Unique Inorganic—Organic Hybrid Mesoporous Materials Incorporating Arenetricarbonyl Complexes [‐C6H4M(CO)3‐](M: Cr, Mo)
Authors: Calhorda M. J. , Nunes C. D. 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Phosphinines as Ligands in Homogeneous Catalysis: Recent Developments, Concepts and Perspectives
Authors: Mueller Christian , Vogt Dieter 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Marine Natural Products
Authors: Blunt John W. , Copp Brent R. , Hu Wan‐Ping , Munro Murray H. G. , Northcote Peter T. , Prinsep Michele R. 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: A Fresh Look at Natural Tropolonoids
Authors: Bentley Ronald 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Fabricating Complex Polymeric Micro‐ and Nanostructures: Lithiography in Microfluidic Devices
Authors: Kane Ravi S. 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Surface Modification of Natural Fibers: Chemical Aspects
Authors: Marechal E. 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Crystal Structure Solution of Organic Compounds from X‐Ray Powder Diffraction Data
Authors: Tsue Hirohito , Horiguchi Masahiro , Tamura Rui , Fujii Kotaro , Uekusa Hidehiro 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Selective NMR Excitations in Chiral Analysis
Authors: Farjon Jonathan , Ziani Latifa , Beguin Laetitia , Merlet Denis , Courtieu Jacques 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Hydrothermal Synthesis and Structural Characterization of the High‐Valent Ruthenium‐Containing Polyoxoanion [{PW11O39}2{(HO)RuIV–O–RuIV(OH)}]10– (Eur. J. Inorg. Chem. 13/2008)
Authors: Chen Su‐Wen , Villanneau Richard , Li Yanling , Chamoreau Lise‐Marie , Boubekeur Kamal , Thouvenot René , Gouzerh Pierre , Proust Anna 
Published: April 2008

AbstractThe cover picture shows the formation of water‐soluble ruthenium derivatives of heteropolytungstates. Depending on the experimental conditions, the authors were able to isolate the new [{PW11O39}2{(HO)RuIV–O–RuIV(OH)}]10– anion. This complex, which has been obtained under hydrothermal conditions, contains an {(HO)RuIV–O–RuIV(OH)} moiety that links two monovacant [α‐PW11O39]7– subunits. It is one of the rare examples of a polyoxometalate that contains noble‐metal cations in a high oxidation state. The strategy for the synthesis and the full characterization in the solid‐state and in solution of this compound are discussed in the article by A. Proust et al. on p. 2137 ff.
The role of cyclodextrins in chiral capillary electrophoresis
Authors: Juvancz Zoltán , Kendrovics Rita Bodáné , Iványi Róbert , Szente Lajos 
Published: April 2008

AbstractThe members of the enantiomeric pairs frequently show rather different biological effects, so their chiral selective synthesis, pharmacological studies and analysis are necessary. CE has unique advantages in chiral analysis. The most frequently used chiral selectors are CDs in this field. This paper gives a short view on the advantages on CE in direct chiral separations, emphasizing the role of CDs. The reason for the broad selectivity spectra of CDs is discussed in detail. The physical background of chiral selective separations is briefly shown in CE. Their interaction mechanisms are shortly defined. The general trend of their use is statistically evaluated. Most frequently used CDs and CD derivatives are characterized. Advantages of ionizable CDs and single‐isomer derivatives are shown. The general trend of their use is established.
Synthesis of (+)‐13‐Stemarene and (+)‐18‐Deoxystemarin: Expeditious Preparation of the Key 6‐exo‐Hydroxybicyclo[2.2.2]octan‐2‐one Ethylene Dithioacetal
Authors: Leonelli Francesca , Caschera Barbara , Silvestri Lavinia , Prastaro Alessandro , Corso Gaia , Ceccacci Francesca , La Bella Angela , Migneco Luisa Maria , Bettolo Rinaldo Marini 
Published: April 2008

AbstractAn expeditious preparation of the 6‐exo‐hydroxybicyclo[2.2.2]octan‐2‐one ethylene dithioacetal 2b, a key intermediate in the synthesis of (+)‐13‐stemarene (4) and (+)‐18‐deoxystemarin (5) is described. Compound 2b was obtained as the major product by equilibrating the endo rich mixture of 6‐hydroxybicyclo[2.2.2]octan‐2‐one ethylene dithioacetals 2 with TsOH in benzene at reflux, easily available from the corresponding hydroxy ketones 9. The model experiments which preceeded the above transformation, not previously described in the literature, are also presented.
Novel Aspects of a Convenient Synthesis and of Electroproperties of Derivatives Based on Diphenylamine
Authors: Idzik Krzysztof , Sołoducho Jadwiga , Cabaj Joanna , Mosiądz Mariusz , Łapkowski Mieczysław , Golba Sylwia 
Published: April 2008

AbstractThe substituted monomers 4a,c,d, 5a,b, 6a, 7a,b, and 8a of novel poly(diphenylamines), possessing the respective photochromic groups, were synthesized by the Stille cross‐coupling methodology (Scheme). The hyperbranched structures were characterized by 1H‐ and 13C‐NMR spectroscopy. The obtained monomers show good stability in common organic solvents such as CHCl3, toluene, and CH2Cl2, and exhibit excellent thermal stability. Electrochemical results and theoretical calculations suggest that oxidation and reduction of the monomers start from the side of the amine function and the five‐membered heterocyclic ring moieties, respectively.
Oligonucleotide Analogues with Integrated Bases and Backbone. Part 17
Authors: Ritter Anne , Egli Daniel , Bernet Bruno , Vasella Andrea 
Published: April 2008

AbstractThe formation of cyclic duplexes (pairing) of known oxymethylene‐linked self‐complementary U*[o]A(*) dinucleosides contrasts with the absence of pairing of the ethylene‐linked U*[ca]A(*) analogues. The origin of this difference, and the expected association of U*[x]A(*) and A*[x]U(*) dinucleosides with x=CH2, O, or S was analysed. According to this analysis, pairing occurs via constitutionally isomeric Watson–Crick, reverse Watson–Crick, Hoogsteen, or reverse Hoogsteen H‐bonded linear duplexes. Each one of them may give rise to three diastereoisomeric cyclic duplexes, and each one of them can adopt three main conformations. The relative stability of all conformers with x=CH2, O, or S were analysed. U*[x]A(*) dinucleosides with x=CH2 do not form stable cyclic duplexes, dinucleosides with x=O may form cyclic duplexes with a gg‐conformation about the C(4′)C(5′) bond, and dinucleosides with x=S may form cyclic duplexes with a gt‐conformation about this bond.The temperature dependence of the chemical shift of HN(3) of the self‐complementary, oxymethylene‐linked U*[o]A(*) dinucleosides 1–6 in CDCl3 in the concentration range of 0.4–50 mM evidences equilibria between the monoplex, mainly linear duplexes, and higher associates for 3, between the monoplex and cyclic duplexes for 6, and between the monoplex, linear, and cyclic duplexes as well as higher associates for 1, 2, 4, and 5.The self‐complementary, thiomethylene‐linked U*[s]A(*) dinucleosides 27–32 and the sequence isomeric A*[s]U(*) analogues 33–38 were prepared by S‐alkylation of the 6‐(mesyloxymethyl)uridine 12 and the 8‐(bromomethyl)adenosine 22. The required thiolates were prepared in situ from the C(5′)‐acetylthio derivatives 9, 15, 19, and 25. The association in CHCl3 of the thiomethylene‐linked dinucleoside analogues was studied by 1H‐NMR and CD spectroscopy, and by vapour‐pressure osmometric determination of the apparent molecular mass. The U*[s]A(*) alcohols 28, 30, and 31 form cyclic duplexes connected by Watson–Crick H‐bonds, while the fully protected dimers 27 and 29 form mainly linear duplexes and higher associates. The diol 32 forms mainly cyclic duplexes in solution and corrugated ribbons in the solid state. The nucleobases of crystalline 32 form reverse Hoogsteen H‐bonds, and the resulting ribbons are cross‐linked by H‐bonds between HOCH2C(8/I) and N(3/I). Among the A*[s]U(*) dimers, only the C(8/I)‐hydroxymethylated 37 forms (mainly) a cyclic duplex, characterized by reverse Hoogsteen base pairing. The dimers 34–36 form mainly linear duplexes and higher associates. Dimers 34 and particularly 38 gelate CHCl3. Temperature‐dependent CD spectra of 28, 30, 31, and 37 evidence π‐stacking in the cyclic duplexes. Base stacking in the particularly strongly associating diol 32 in CHCl3 solution is evidenced by a melting temperature of ca. 2°.
Improved Synthesis of Phytosphingosine and Dihydrosphingosine from 3,4,6‐Tri‐O‐benzyl‐D‐galactal
Authors: Niu Youhong , Cao Xiaoping , Ye Xin‐Shan 
Published: April 2008

AbstractAn efficient and facile synthesis of phytosphingosine and dihydrosphingosine derivatives is described with less steps and in improved overall yield (66–72%) starting from commercially available tri‐O‐benzyl‐D‐galactal. The key steps include Wittig reaction, Mitsunobu transformation, reduction, and deprotection.
Quantitation of cardioexcitatory Asn‐D‐Trp‐Phe‐NH2 diastereomers in Aplysia's central nervous system by nanoscale liquid chromatography‐tandem mass spectrometry
Authors: Song Yaru , Liu Yi‐Ming 
Published: April 2008

AbstractA tripeptide, Asn‐D‐Trp‐Phe‐NH2 (NdWFa) that contains a D‐amino acid residue (i.e. D‐tryptophan) was previously identified in Aplysia's central nervous system (CNS) and found to be cadioexcitatory. However, the occurrence of its diastereomers including NWFa, theoretically the precursor of NdWFa, remains largely unknown. In this work, a nanoscale liquid chromatographic/tandem mass spectrometric (nano‐LC‐MS/MS) method was developed for a sensitive determination of the diastereomers of NWFa. Resolution of the diastereomers including NWFa, NdWFa, NWdFa, and dNWFa was achieved on capillary columns packed with C18 silica particles with an MS detection‐friendly mobile phase consisting of water, acetonitrile, and formic acid. Columns of different internal diameters (IDs) ranging from 75 to 250 µm were evaluated to achieve the best sensitivity. With the use of a 75 µm ID column integrated with a nanoelectrospray emitter, the method had limits of detection (LOD) of 0.21 nM (or 0.49 pg on column, 5 µl injected) NdWFa in tissue homogenate (S/N = 3). The five major ganglia in Aplysia californica's CNS (i.e. buccal, cerebral, abdominal, plural, and pedal) were analyzed. NdWFa was detected only in abdominal ganglion at the ng/g tissue level. Further, its diastereomer, NWFa, was also detected for the first time and also only in abdominal ganglion at a significantly lower level. The levels of both NWFa and NdWFa varied from animal to animal in the range from 0 to 81 ng/g tissue. Copyright © 2008 John Wiley & Sons, Ltd.
Rapid screening and characterization of drug metabolites using a multiple ion monitoring–dependent MS/MS acquisition method on a hybrid triple quadrupole‐linear ion trap mass spectrometer
Authors: Yao Ming , Ma Li , Humphreys W. Griffith , Zhu Mingshe 
Published: April 2008

AbstractA novel LC/MS/MS method that uses multiple ion monitoring (MIM) as a survey scan to trigger the acquisition of enhanced product ions (EPI) on a hybrid quadrupole‐linear ion trap mass spectrometer (Q TRAP) was developed for drug metabolite identification. In the MIM experiment, multiple predicted metabolite ions were monitored in both Q1 and Q3. The collision energy in Q2 was set to a low value to minimize fragmentation. Results from analyzing ritonavir metabolites in rat hepatocytes demonstrate that MIM‐EPI was capable of targeting a larger number of metabolites regardless of their fragmentation and retained sensitivity and duty cycle similar to multiple reaction monitoring (MRM)‐EPI. MIM‐based scanning methods were shown to be particularly useful in several applications. First, MIM‐EPI enabled the sensitive detection and MS/MS acquisition of up to 100 predicted metabolites. Second, MIM‐MRM‐EPI was better than MRM‐EPI in the analysis of metabolites that undergo either predictable or unpredictable fragmentation pathways. Finally, a combination of MIM‐EPI and full‐scan MS (EMS), as an alternative to EMS‐EPI, was well suited for routine in vitro metabolite profiling. Overall, MIM‐EPI significantly enhanced the metabolite identification capability of the hybrid triple quadrupole‐linear ion trap LC/MS. Copyright © 2008 John Wiley & Sons, Ltd.
Influence of thermo‐oxidative degradation on the biodegradability of lubricant base oils
Authors: Beran Elżbieta , Łoś Magdalena , Kmiecik Aleksandra 
Published: April 2008

AbstractThe paper addresses the problem of how the thermo‐oxidative changes in the chemical structure influence the biodegradability of lubricating base oils. The tests were conducted using synthetic polyolesters, polyalphaolefins (PAO 4) and blended polyolesters with 30 wt % of PAO 4. Oil biodegradability was evaluated in accordance with the International Standards Organization (ISO) 14593 test. The thermo‐oxidative degradation consisted of a 24‐hour exposure of the oil samples to the temperature of 150°C in a universal test apparatus at an air flow rate of 15 L/hour. The results have revealed that the thermo‐oxidative degradation of the chemical structure produces changes in the physico‐chemical properties of the base oils and improves biodegradability. The polyolester oils tested were found to be readily biodegradable both before and after thermo‐oxidative tests. PAO 4 oil and its blends with polyolester oils could not be classified as readily biodegradable. The thermo‐oxidative changes in their chemical structures can exert a positive effect on their biodegradability. Copyright © 2008 John Wiley & Sons, Ltd.
Tourism in Trinidad and Tobago: carving a niche in a petroleum‐based economy
Authors: Lewis Acolla , Jordan Leslie‐Ann 
Published: April 2008

AbstractTrinidad and Tobago lies within one of the world's most tourism‐intensive regions, the Caribbean. Yet, unlike its neighbours, it has not relied heavily on income from travel and tourism since its economy is dominated by the energy sector. The energy sector is the mainstay of the economy contributing approximately 34.1% to the country's GDP, 85.5% to merchandise exports and 37.1% to Government revenues in 2004 (Ministry of Energy, 2006). The Government, in its aim for developed nation status by 2020, recognizes that the energy sector is unable to provide the sustainable jobs needed to achieve this. Thus, the Government's policy strategy, Vision 2020, identifies tourism as one of five (5) sectors that should be developed to contribute to the country's economic development.The tourism industry currently represents 13.8% of total Gross Domestic Product (GDP) in Trinidad and Tobago and is expected to increase its share by nearly three percentage points to 16.5% by 2015. It accounts for 16.7% of total employment, and this is forecasted to rise to 19.2% (WTTC, 2005). Several challenges are evident, that continue to limit the industry's full potential for growth in the country. It is against this background that this paper seeks to identify and analyse the strategies that can be adopted to maximize the contribution of the hospitality and tourism industry to economic development in Trinidad and Tobago. The three main strategies proposed are a greater focus on local entrepreneurship; the re‐orientation of the role of the local financial mechanisms in tourism development and; the development of competitive tourism investment incentives for potential investors in the hospitality and tourism industry. Copyright © 2008 John Wiley & Sons, Ltd.
Conductive Composites of Polyurethane Resins and Ionic Liquids
Authors: Berns Belinda , Deligöz Hüseyin , Tieke Bernd , Kremer Friedrich 
Published: April 2008

AbstractComposites of PUR and IL were prepared and specific conductivities and Shore A hardness were determined. IL were based on 1‐alkyl‐3‐methylimidazolium salts with counterions BF, PF, triflate, or ethylsulfate. Presence of IL increased the conductivity by five orders of magnitude. Variation of alkyl chain length and nature of counterions only had little effect on the conductivity. Presence of IL had a plasticizing effect, which was most pronounced for the IL with dodecyl groups and PF as counterion. In broadband dielectric measurements, the complex conductivity showed a characteristic dispersion that is caused by the interplay between (hopping) transport of charge carriers and electrode polarization.magnified image
Quantification of viable tumor microvascular characteristics by multispectral analysis
Authors: Berry Leanne R. , Barck Kai H. , Go Mary Ann , Ross Jed , Wu Xiumin , Williams Simon P. , Gogineni Alvin , Cole Mary J. , Van Bruggen Nicholas , Fuh Germaine , Peale Frank , Ferrara Napoleone , Ross Sarajane , Schwall Ralph H. , Carano Richard A.D. 
Published: April 2008

AbstractTumor heterogeneity complicates the quantification of tumor microvascular characteristics assessed by dynamic contrast‐enhanced MRI (DCE‐MRI). To address this issue a novel approach was developed that combines DCE‐MRI with diffusion‐based multispectral (MS) analysis to quantify the microvascular characteristics of specific tumor tissue populations. Diffusion‐based MS segmentation (feature space: apparent diffusion coefficient, T2 and proton density) was performed to identify tumor tissue populations and the DCE‐MRI characteristics were determined for each tissue class. The ability of this MS DCE‐MRI technique to detect microvascular changes due to treatment with an antibody (G6‐31) to vascular endothelial growth factor‐A (VEGF) was evaluated in a tumor xenograft mouse model. Anti‐VEGF treatment resulted in a significant reduction in Ktrans for the MS viable tumor tissue class (−0.0034 ± 0.0022 min−1, P < 0.01) at 24 hr posttreatment that differ significantly from the change observed in the control group (0.0002 ± 0.0025 min−1). Viable tumor Ktrans for the anti‐VEGF group was also reduced 62% relative to the pretreatment values (P < 0.01). Necrotic tissue classes were found to add only noise to DCE‐MRI estimates. This approach provides a means to measure physiological parameters within the viable tumor and address the issue of tumor heterogeneity that complicates DCE‐MRI analysis. Magn Reson Med, 2008. © 2008 Wiley‐Liss, Inc.
Compartment size estimation with double wave vector diffusion‐weighted imaging
Authors: Koch Martin A. , Finsterbusch Jürgen 
Published: April 2008

AbstractDouble wave vector diffusion weighting uses gradients along two different directions between excitation and acquisition. It has been shown theoretically that for restricted diffusion the signal amplitude in such an experiment can depend on the angle between the two gradient vectors. The highest amplitude is obtained with antiparallel orientation, and the amplitude difference between parallel and antiparallel gradient orientations depends on the compartment size. The validity of this description is experimentally tested for water between polymer beads, for radish, and for porcine spinal cord, using a clinical MR system with limited gradient strength. The results indicate that the phenomenon is observable; however, the size of the signal difference is considerably diminished when compared with theory. This is attributed to violations of the approximating conditions underlying the theoretical description and to free diffusion contributions. It is concluded that the effect could successfully be used as a basis for developing a new noninvasive method for assessing cell size. Magn Reson Med, 2008. © 2008 Wiley‐Liss, Inc.