bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectroscopic and Photophysical Properties of a Highly Derivatized C60 Fullerol
Authors: Vileno B. , Marcoux P. R. , Lekka M. , Sienkiewicz A. , Fehér T. , Forró L. 
Published: November 2005

AbstractHydroxylated C60 molecules, also called fullerols, are a class of water‐soluble fullerenes. Here we report the synthesis in acidic conditions of a highly derivatized fullerol (up to 36 carbons per C60 are oxidized). Spectroscopic investigations (X‐ray photoelectron spectroscopy and infrared absorption) highlight the coexistence of both acidic and basic forms for the hydroxyl addends of derivatized C60. pH titrimetry reveals that, at millimolar concentrations, only ten protons per fullerol molecule are labile. Such a low value, as compared to 36 hydroxyl groups, is explained by the formation of clusters. A UV‐vis absorption study performed over a large range of concentrations also points to the aggregation phenomenon. Moreover, this study shows that the clusters of fullerols appear at relatively low (micromolar) concentrations. An electron spin resonance (ESR) study, based on the attack of singlet oxygen (1Δg) on 2,2,6,6‐tetramethyl‐4‐piperidinol (TMP‐OH), has proved the potential of hydroxylated C60 for performing efficient generation of singlet oxygen in aqueous solution. ESR measurements, which allow detection and quantification of 1Δg, have also revealed the generation of reactive oxygen species (ROS). The yield of generation of 1Δg and ROS is strongly correlated to the concentration of fullerol, thus also pointing to the aggregation of fullerol molecules. Exposing glioblastoma cells to oxidative stress in the presence of hydroxylated C60 and visible light has also been performed. Atomic force microscopy is used to monitor the relevant diminishment of the Young's modulus values for cells exposed to the oxidative stress. These results point to a possible application field of fullerols for performing bio‐oxidations.
Force Spectroscopic Investigations During the Local Oxidation of n‐Octadecyltrichlorosilane Monolayers
Authors: Hoeppener S. , van Schaik J. H. K. , Schubert U. S. 
Published: November 2005

AbstractScanning force spectroscopy (SFS) is a powerful tool for investigating surface properties with high precision. Unlike most common spectroscopic techniques, information about local properties can also be obtained from surface areas with nanometer dimensions. This makes SFS a useful investigative tool for small lithographic structures. We apply the continuous recording of force curves to extract valuable information about the local oxidation of a monolayer of n‐octadecyltrichlorosilane molecules self‐assembled on silicon. The oxidation is carried out while simultaneously recording the force curves during the application of a bias voltage to the tip. The dynamics of the induced surface modifications and changes in the surface properties are followed by analyzing specific spots in the force curves.
Fluorescence‐Amplifying Detection of Hydrogen Peroxide with Cationic Conjugated Polymers, and Its Application to Glucose Sensing
Authors: He F. , Tang Y. , Yu M. , Wang S. , Li Y. , Zhu D. 
Published: November 2005

AbstractA highly sensitive hydrogen peroxide probe that takes advantage of the amplified fluorescence quenching of conjugated polymers has been developed. The cationic conjugated polymer, poly(9,9‐bis(6′‐N,N,N‐trimethylammonium‐hexyl) fluorene phenylene) (PFP‐NMe3+) and peroxyfluor‐1 with boronate protecting groups (Fl‐BB) are used to detect H2O2 optically. Without the addition of H2O2, the absence of electrostatic interactions between the cationic PFP‐NMe3+ and the neutral Fl‐BB keeps the Fl‐BB well separated from the PFP‐NMe3+, and no fluorescence quenching of the PFP‐NMe3+ occurs. In the presence of H2O2, the formation of the anionic quencher, fluorescein, by specific reaction of the Fl‐BB with H2O2 results in strong electrostatic interactions between the PFP‐NMe3+ and the fluorescein, and therefore efficient fluorescence quenching of the PFP‐NMe3+ occurs. The absorption of fluorescein overlaps the emission of PFP‐NMe3+, which encourages fluorescence resonance energy transfer (FRET) from the PFP‐NMe3+ to the fluorescein. The H2O2 probe has very good sensitivity, with a detection range of 15 to 600 nM. Since glucose oxidase (GOx) can specifically catalyze the oxidation of β‐D‐(+)‐glucose to generate H2O2, glucose detection is also realized with the H2O2 probe as the signal transducer.
Liquid Phase Oxidation of Toluene to Benzaldehyde with Molecular Oxygen over Copper‐Based Heterogeneous Catalysts
Authors: Wang Feng , Xu Jie , Li Xiaoqiang , Gao Jin , Zhou Lipeng , Ohnishi Ryuichiro 
Published: December 2005

AbstractWe conducted the liquid phase oxidation of toluene with molecular oxygen over heterogeneous catalysts of copper‐based binary metal oxides. Among the copper‐based binary metal oxides, iron‐copper binary oxide (Fe/Cu=0.3 atomic ratio) was found to be the best catalyst. In the presence of pyridine, overoxidation of benzaldehyde to benzoic acid was partially prevented. As a result, highly selective formation of benzaldehyde (86% selectivity) was observed after 2 h of reaction (7% conversion of toluene) at 463 K and 1.0 MPa of oxygen atmosphere in the presence of pyridine. These catalytic performances were similar or better than those in the gas phase oxidation of toluene at reaction temperatures higher than 473 K and under 0.5–2.5 MPa. It was suggested from competitive adsorption measurements that pyridine could reduce the adsorption of benzaldehyde. At a long reaction time of 4 h, the conversion increased to 25% and benzoic acid became the predominant reaction product (72% selectivity) in the absence of pyridine. The yield of benzoic acid was higher than that in the Snia‐Viscosa process, which requires corrosive halogen ions and acidic solvents in the homogeneous reaction media. The catalyst was easily recycled by simple filtration and reusable after washing and drying.
New Carbohydrate‐Based Phosphite‐Oxazoline Ligands as Highly Versatile Ligands for Palladium‐Catalyzed Allylic Substitution Reactions
Authors: Mata Yvette , Diéguez Montserrat , Pàmies Oscar , Claver Carmen 
Published: December 2005

AbstractWe have designed and synthesized a new family of readily available phosphite‐oxazoline ligands for Pd‐catalyzed asymmetric allylic substitution reactions. These ligands can be tuned in two regions to explore their effect on catalytic performance. By carefully selecting the ligand components, we obtained high enantioselectivities in the Pd‐catalyzed allylic substitution in substrates with different steric properties
Topological Mapping of Bidentate Ligands: A Fast Approach for Screening Homogeneous Catalysts
Authors: Burello Enrico , Rothenberg Gadi 
Published: December 2005

AbstractThe challenge of predicting the catalytic properties of large libraries of homogeneous catalysts is introduced. A new concept is presented that combines fundamental chemical topology principles with linear and non‐linear statistical analysis. These models can predict key properties of bidentate ligand‐metal complexes, namely the ligand bite angle and the backbone flexibility, without computing any 3D structural parameters and without using any force fields or any quantum mechanics. The model's performance is demonstrated on a set of 80 biphosphine and biphosphite complex crystal structures. With non‐linear methods, the prediction accuracy is 93% for bite angles and 90% for flexibilities. The link between the descriptors and the ligand structures, and the possibilities that this approach opens in the search for new homogeneous catalysts are discussed.
Palladium Nanoclusters in Sonogashira Cross‐Coupling: A True Catalytic Species?
Authors: Thathagar Mehul B. , Kooyman Patricia J. , Boerleider Romilda , Jansen Eveline , Elsevier Cornelis J. , Rothenberg Gadi 
Published: December 2005

AbstractThe question of whether palladium nanoclusters are the actual catalysts in the so‐called ‘cluster–catalyzed Sonogashira cross‐coupling’ is investigated, using the coupling of phenylacetylene with 4‐bromobenzonitrile as a model reaction. By combining a detailed kinetic analysis with transmission electron microscopy (TEM), we show that a soluble species must be present in the system when Pd nanoclusters are used as catalysts. Various Pd clusters show similar kinetic profiles to that of a homogeneous Pd(dba)2 complex. Most importantly, TEM analysis of samples taken before, during, and after the reaction shows that the cluster size decreases during the reaction. Based on these findings, we present a possible two‐path mechanism for Sonogashira cross‐coupling reactions in the presence of Pd nanoclusters.
A New Chiral P,N‐Ligand Derived from 1‐Phenylphospholane‐2‐carboxylic Acid (Phenyl‐P‐proline) for Palladium‐Catalyzed Asymmetric Allylic Substitution Reactions
Authors: Sun Xiang‐Min , Koizumi Masatoshi , Manabe Kei , Kobayashi Shū 
Published: December 2005

AbstractNew types of P,N‐ligands, cis‐ and trans‐3, containing a tetrahydroisoquinoline skeleton as an N‐donor were synthesized from (1R,2S)‐1‐phenylphospholane‐2‐carboxylic acid (phenyl‐P‐proline, 1). The cis isomer, cis‐3, was found to act as an excellent ligand in palladium‐catalyzed asymmetric allylic substitution reactions. The reactions of 1,3‐diphenyl‐2‐propenyl acetate (5) with several nucleophiles in the presence of [Pd(π‐allyl)Cl]2, cis‐3 (Pd : ligand=1 : 2), and a base afforded the desired products in high yields with high enantioselectivity. It was suggested that these ligands did not serve as P,N‐bidentate ligands but as P‐monodentate ligands in these reactions.
L‐Prolinethioamides – Efficient Organocatalysts for the Direct Asymmetric Aldol Reaction
Authors: Gryko Dorota , Lipiński Radosław 
Published: December 2005

AbstractA series of novel L‐proline derived thioamides has been synthesised. They have been evaluated as organocatalysts in the direct asymmetric aldol reaction for the first time. Thioamides exhibit catalytic ability higher than proline itself and the model aldol reaction of 4‐cyanobenzaldehyde with acetone proceeds well in the presence of 5 mol % of catalyst (ee up to 100%). Other aromatic aldehydes gave aldol products with high ees and moderate yields. Small changes in the catalyst's structure [e.g., N‐Bn versus N‐CH(CH3)Ph] as well as the addition of an acid have a profound effect on their activity. The unexpected formation of the catalyst‐derived cyclic adducts was observed and their reactivity was established giving valuable insight into the course of the reaction.
Vanadium‐Catalyzed Enantioselective Sulfoxidation and Concomitant, Highly Efficient Kinetic Resolution Provide High Enantioselectivity and Acceptable Yields of Sulfoxides
Authors: Zeng Qingle , Wang Heqing , Wang Tongjian , Cai Yimin , Weng Wen , Zhao Yufen 
Published: December 2005

AbstractSimple, inexpensive, preformed vanadium‐Schiff base complexes were facilely prepared and used in enantioselective sulfoxidation. Both the amount of aqueous H2O2 and reaction time greatly influenced the ee values and yields of chiral sulfoxides. High enantioselectivities (up to 99% ee) and reasonable yields (>40%) for various chiral sulfoxides were achieved by combining enantioselective sulfoxidation and appropriate concomitant kinetic resolution.
Isolated 6q terminal deletions: An emerging new syndrome
Authors: Bertini Veronica , De Vito Giuseppe , Costa Rosa , Simi Paolo , Valetto Angelo 
Published: December 2005

AbstractDeletions of the distal part of the 6q chromosome have not been associated with a clearly distinctive and recognizable phenotype. In order to determine if a “6q terminal deletion syndrome” could be delineated, we compared the phenotype of two new cases with those patients reported in literature presenting with a similar deletion. Cases with more complex karyotypes were excluded. The deletion in our patients was accurately analyzed by loss of heterozygosity (LOH) and fluorescence in situ hybridization (FISH) with a panel of probes located around the putative breakpoint. Interestingly, the breakpoints were located in 6q26 in both our patients, distally to clone RP11‐150P20 and proximally to clone RP11‐152P19, with a deletion size of approximately 8 Mb. The breakpoints fall within the fragile site FRA6E. From a careful evaluation of the selected patients, a common phenotype emerged, including psychomotor retardation, hypotonia, seizures, short neck, and typical facial anomalies, along with nonspecific anomalies. While these features are shared by other chromosome syndromes and are not sufficient on their own for a clinical diagnosis, when considered together, the pattern can allow the identification of the “6q terminal deletion syndrome.” Moreover, the potential role of FRA6E in generating these deletions is suggested. © 2005 Wiley‐Liss, Inc.
HRAS mutation analysis in Costello syndrome: Genotype and phenotype correlation
Authors: Gripp Karen W. , Lin Angela E. , Stabley Deborah L. , Nicholson Linda , Scott Charles I. , Doyle Daniel , Aoki Yoko , Matsubara Yoichi , Zackai Elaine H. , Lapunzina Pablo , Gonzalez‐Meneses Antonio , Holbrook Jennifer , Agresta Cynthia A. , Gonzalez Iris L. , Sol‐Church Katia 
Published: December 2005

AbstractCostello syndrome is a rare condition comprising mental retardation, distinctive facial appearance, cardiovascular abnormalities (typically pulmonic stenosis, hypertrophic cardiomyopathy, and/or atrial tachycardia), tumor predisposition, and skin and musculoskeletal abnormalities. Recently mutations in HRAS were identified in 12 Japanese and Italian patients with clinical information available on 7 of the Japanese patients. To expand the molecular delineation of Costello syndrome, we performed mutation analysis in 34 North American and 6 European (total 40) patients with Costello syndrome, and detected missense mutations in HRAS in 33 (82.5%) patients. All mutations affected either codon 12 or 13 of the protein product, with G12S occurring in 30 (90.9%) patients of the mutation‐positive cases. In two patients, we found a mutation resulting in an alanine substitution in position 12 (G12A), and in one patient, we detected a novel mutation (G13C). Five different HRAS mutations have now been reported in Costello syndrome, however genotype–phenotype correlation remains incomplete. © 2005 Wiley‐Liss, Inc.
Inbreeding and surnames: A projection into Easter Island's past
Authors: González‐Martín Antonio , García‐Moro Clara , Hernández Miguel , Moral Pedro 
Published: December 2005

AbstractThe population of Easter Island is one of the most interesting extant human communities due to its unique demographic history, its geographic isolation, and the development of an incomparable culture characterized by the towering “Moais” and its enigmatic writing. Following the colonization of its population by Polynesians from the Mangarevan Islands in the 5th century AD, the island remained isolated up until the middle of the 20th century. Under these conditions, with endogamy levels fluctuating between 61.04–96.54% and given such a small population, a high rate of inbreeding, and consequently, an elevated level of genetic relationships would be expected. Using data from church and civil records, we calculated the consanguinity of the population of Rapa Nui. The results of this analysis do not support the hypothesis of a high level of consanguinity (α = 0.00028 and Ft = 0.0007, with Fr = 0.00586 and Fn = −0.00519), suggesting instead the existence of a strategy used to avoid marriage between close relatives. To explain these observations, the structure and exchange dynamics of the population were studied in the tribes, known locally as “Mata.” The results of this analysis suggest a tendency toward the avoidance of inbreeding within tribes, in order to decrease the rate of endogamy in each group. This is consistent with ethnographic observations from the beginning of the 20th century that support the existence of strict regulations to prevent inbreeding between closely related individuals. Furthermore, we confirm that this situation dates back to a period before the “refounding” of Easter Island. Our results demonstrate that conditions of geographical isolation are not in themselves sufficient to produce an elevated inbreeding coefficient, revealing Easter Island as an interesting example of how cultural rules can shape the genetic structure of a population. Am J Phys Anthropol, 2006. © 2005 Wiley‐Liss, Inc.
New solid polymer electrolytes based on PEO/PAN hybrids
Authors: Chun‐Guey Wu , Chiung‐Hui Wu , Ming‐I Lu , Huey‐Jan Chuang 
Published: November 2005

AbstractHybrid polymer dry electrolytes comprised of poly(ethylene oxide) (PEO), polyacrylonitrile (PAN), and LiClO4 were investigated. The impedance spectroscopy showed that the effect of PAN on the ion conductivity of PEO‐based electrolytes depends on the concentration of lithium salt. When the mole ratio of lithium to oxygen is 0.062 (15%LiClO4‐PEO), adding PAN will increase the ionic conductivity. Differential scanning calorimetry, NMR, and IR data suggested that the enhanced conductivity was due to both the decreasing of the PEO crystallinity and increasing of the degree of ionization of lithium salt. There was obviously no interaction between PAN and lithium ions, and PAN acts as a reinforcing filler, and hence contributes to the mechanical strength besides reducing the crystallinity of the polymer electrolytes. When the LiClO4‐PEO‐PAN hybrid polymer electrolyte was heated at 200°C under N2, PAN crosslinked partially, which further decreased the crystallinity of PEO and increased the ionic conductivity, and at the same time prevented the recrystallization of PEO upon sitting at ambient environment. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1530–1540, 2006
Generation of neoantigenic epitopes after posttranslational modification of type II collagen by factors present within the inflamed joint
Authors: Nissim Ahuva , Winyard Paul G. , Corrigall Valerie , Fatah Rewas , Perrett David , Panayi Gabriel , Chernajovsky Yuti 
Published: December 2005

AbstractObjectiveCollagen‐induced arthritis is a commonly accepted model of rheumatoid arthritis (RA). However, it has been difficult to substantiate the involvement of autoimmunity to type II collagen (CII) in the pathogenesis of RA. The aim of this investigation was to determine if CII, modified by reactive oxidant species present within the inflamed joint, could generate neoantigenic epitopes.MethodsOxidants that play a role in acute and chronic inflammation and are present in the rheumatoid joint (hydroxyl radical, hypochlorous acid, and peroxynitrite) were used for modification of native CII. In addition, CII was glycated with ribose, since nonenzymatic oxidative reactions by glycation are evident in RA. Modifications were analyzed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and 3‐dimensional fluorescence followed by enzyme‐linked immunosorbent assay (ELISA) and Western blotting, using, as probes, sera from patients with RA and from patients with other inflammatory and noninflammatory joint diseases.ResultsOnly 1 RA serum sample showed strong binding to native CII. In contrast, binding to modified CII was increased in 14 of 31 RA sera, of which 7 were strong binders and 7 were moderate binders. Among the non‐RA serum samples, only 1 yielded a strong reaction to modified CII and 5 of 41 were moderate binders. Samples that showed the strongest binding to modified CII in ELISA also showed strong binding to various fragmented or aggregated forms of CII in Western blots, as well as strong binding to fragmented CII present in RA synovial fluid.ConclusionWhen modified by conditions found within the inflamed joint, CII acts as an autoantigen in RA.
Tissue trafficking patterns of effector memory CD4+ T cells in rheumatoid arthritis
Authors: Zhang Xiaoyu , Nakajima Takako , Goronzy Jörg J. , Weyand Cornelia M. 
Published: December 2005

AbstractObjectiveClonal populations of CD4+,CD28− T cells accumulating in rheumatoid arthritis functionally resemble end‐differentiated, nondividing, short‐lived effector memory cells that reside in peripheral tissues. We undertook this study to examine the tissue niche for CD4+,CD28− T cells and the signals regulating their survival and tissue homing patterns.MethodsChemokine receptor expression on CD4+,CD28− T cell clones and peripheral blood lymphocytes was assessed by multicolor cytometry. In vitro chemotaxis and transendothelial migration were examined in a Transwell system. In vivo tissue‐homing patterns were established by adoptively transferring fluorescence‐labeled T cell clones into SCID mice engrafted either with rheumatoid synovium or with human lymph nodes.ResultsCD4+,CD28− T cell clones adoptively transferred into human tissue–SCID mouse chimeras infiltrated rheumatoid synovium but preferentially homed to lymph nodes. Such T cells coexpressed the chemokine receptors CCR7, CCR5, and CXCR4 and migrated in response to both inflammatory chemokines (CCL5) and homing chemokines (CXCL12). T cell receptor crosslinking abrogated chemotactic responsiveness. In contrast, interleukin‐12 stimulation induced the up‐regulation of CCR5 and a shift in the in vivo homing pattern away from the lymph nodes toward the inflamed synovium.ConclusionCD4+,CD28− T cells resemble both short‐lived effector memory cells and long‐lived central memory cells, and they find a niche both in inflamed synovium and in lymph nodes. Nonspecific cytokine stimulation, not antigen recognition, triggers the transition from the lymph node to the synovium. By maintaining CCR7 expression, these end‐differentiated T cells can home to lymphoid organs, enhance their survival, support clonal expansion, and perpetuate autoreactivity.
Early specialist repair of biliary injury
Authors: Thomson B N J , Parks R W , Madhavan K K , Wigmore S J , Garden O J 
Published: December 2005

Abstract

Background
Considerable debate surrounds the timing of repair of injury to the common bile duct following cholecystectomy. In the absence of sepsis or significant peritoneal soiling, repair within the first week may be optimal. This study compared the outcome of early (within the first 2 weeks) and delayed (between 2 weeks and 6 months) repair.

Methods
Data on all patients referred with biliary injuries were recorded prospectively. In the absence of sepsis or significant peritoneal soiling, repair was considered within 2 weeks.

Results
Between November 1988 and November 2003, 123 patients were referred with injury to the biliary tree. Repair of the injury had been attempted in 55 patients (44·7 per cent) before referral. Of the 68 patients with no previous repair, nine were managed without surgery and 59 required subsequent surgical reconstruction of the ductal injury. Within the first 2 weeks after injury, 22 patients underwent primary biliary repair and three had revision of a failed biliary repair. Between 2 weeks and 6 months, a further 22 injuries were repaired. Successful repair was possible in 22 of 25 early repairs compared with 20 of 22 delayed repairs (P = 0·615). The overall operative mortality rate for patients undergoing repair was 4 per cent (two of 47 patients).

Conclusion
A successful outcome was achieved in a high proportion of patients (42 of 47) when repair of the bile duct injury was undertaken in a unit experienced in the management of biliary injury. In selected patients, early repair within the first 2 weeks resulted in a similar outcome to that of delayed repair.
Facile and Convenient Synthesis of Functionalized Propargylic Alcohols and Amines: An InBr3—Et3N Reagent System Promotes the Alkynylation of Aldehydes and N,O‐ or N,S‐Acetals.
Authors: Sakai Norio , Kanada Reiko , Hirasawa Maki , Konakahara Takeo 
Published: November 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
N‐Vinyl‐ and C‐Vinylpyrroles from Azafulvenium Methides. Flash Vacuum Pyrolysis Route to 5‐Oxo‐5H‐pyrrolizines and 1‐Azabenzo[f]azulenes.
Authors: Pinho e Melo Teresa M. V. D. , Soares Maria I. L. , d'A. Rocha Gonsalves Antonio M. , Paixao Jose A. , Beja Ana Matos , Ramos Silva Manuela 
Published: November 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.