bluuebunny/crossref_metadata_2025_split huggingface dataset:
Self‐Assembling Structures of Long‐Chain Sugar‐Based Amphiphiles Influenced by the Introduction of Double Bonds
Authors: Jung Jong Hwa , Do Youngkyu , Lee Young‐A , Shimizu Toshimi 
Published: July 2005

AbstractNine phenyl glucoside or galactoside amphiphiles possessing a saturated or unsaturated long alkyl‐chain group as the self‐assembling unit of a highly organized molecular architecture were synthesized. Their self‐assembly properties were investigated by using energy‐filtering TEM (EF‐TEM), SEM, CD, XRD, and FT‐IR techniques. Compound 2, possessing one cis double bond in the lipophilic portion, exhibited twisted helical fibers, which formed a bilayered structure with a 3.59 nm period, while 3 exhibited helical ribbons and left‐handed nanotubular structures with 150–200 nm inner diameters and a wall thickness of approximately 20 nm. Very interestingly, 4, possessing three cis double bonds, exhibited a nanotubular structure with an inner diameter of approximately 70 nm and a d spacing value of 4.62 nm. On the other hand, 7, possessing two trans double bonds in the lipophilic region, exhibited crystal‐ or plate‐like structures, which formed a bilayer structure with a d spacing value of 3.93 nm. These results indicate that the self‐assembly properties are strongly dependent on the type of double bond. Furthermore, 8 and 9, with the galactopyranose moiety, revealed helical ribbon and well‐defined double helical fiber structures, respectively. These findings support the view that the orientation of the intermolecular hydrogen‐bonding interaction between the sugar moieties plays a critical role in producing the nanotubular structures. According to CD and powder XRD experiments, the relatively strong intermolecular hydrogen‐bonding interaction of the glucopyranoside moiety in 3 and 4 provided a highly ordered chiral packing structure. Even though these compounds formed a weak hydrophobic interaction between lipophilic groups, it led to the formation of the nanotubular structure.
Structural Diversity of α‐Amino Acid Based Layer‐Block Dendrons and Their Layer‐Block Sequence‐Dependent Gelation Properties
Authors: Chow Hak‐Fun , Zhang Jie 
Published: July 2005

AbstractA library of G1–G3 α‐amino acid based layer‐block dendrons 1–6 containing different amino acid residues in the different concentric layers was prepared by solution‐phase peptide synthesis. The structures of these dendrons were characterized by 1H and 13C NMR spectroscopy and, except for the G3 series of compounds, by mass spectrometry. The purities of these compounds were also determined by size‐exclusion chromatography. Owing to the presence of a large number of amide groups, these dendrons exhibit unusually strong self‐aggregating properties in both polar and nonpolar solvents. Some of these dendrons are found to be extremely good organogelators towards aromatic solvents with minimum gel concentrations approaching 4 mg mL−1. Their gelation ability is found to be highly dependent on the nature of the amino acid compositions, the amino acid layer‐block sequence within the dendritic architecture and the nature of the focal‐point functionality. IR spectroscopic analysis indicates that gelation is induced by intermolecular hydrogen bonds. Circular dichroism studies suggest the formation of hierarchical chiral structures in the gel state, although the existence of chiral morphologies could not be observed by scanning electron microscopy.
Highly Stable Neutral and Positively Charged Dicarbollide Sandwich Complexes
Authors: Núñez Rosario , Tutusaus Oscar , Teixidor Francesc , Viñas Clara , Sillanpää Reijo , Kivekäs Raikko 
Published: July 2005

AbstractNovel sandwich metallacarboranes commo‐[3,3′‐Ni(8‐SMe2‐1,2‐C2B9H10)2] (1), commo‐[3,3′‐Co(8‐SMe2‐1,2‐C2B9H10)2]+ (2+), commo‐[3,3′‐Ru(8‐SMe2‐1,2‐C2B9H10)2] (4) and commo‐[3,3′‐Fe(8‐SMe2‐1,2‐C2B9H10)2] (5) have been prepared by reaction of [10‐SMe2‐7,8‐nido‐C2B9H10]− with NiCl2⋅6 H2O, CoCl2, [RuCl2(dmso)4] and [FeCl2(dppe)], respectively. Reduction of 2+ with metallic Zn leads to the neutral and isolable complex commo‐[3,3′‐Co(8‐SMe2‐1,2‐C2B9H10)2] (3). Theoretical calculations using the ZINDO/1 semiempirical method show three energy minima for complexes 1–3 and 5 that agree with the presence of three different rotamers in solution at low temperature, while four relative energy minima have been found for 4. The calculated rotational energy barriers for complexes 1–5 have been found in the range 5.2±0.2 and 11.5±0.2 kcal mol−1. These values are in agreement with the experimental data calculated for complexes 2+ and 5. Only one rotamer is found in the X‐ray crystal structure of complexes 1–3, while two are observed for 4. Neutral complexes 1, 3 and 4 exhibit a gauche conformation, whereas a cisoid conformation is found for the 2+ ion. Rotamers evident from X‐ray diffraction studies are in agreement with the global energy minimum calculated by the ZINDO/1 method. The electrochemical studies conducted on 1, 3, 4 and 5 support the proposal that the charge‐compensated ligand [10‐SMe2‐7,8‐nido‐C2B9H10]− stabilises lower oxidation states in metals than the dianionic [7,8‐nido‐C2B9H11]2− and even the [C5H5]− ligands.
Using navigators to improve care of underserved patients
Authors: Dohan Daniel , Schrag Deborah 
Published: July 2005

AbstractBACKGROUNDLogistic, cultural, educational, and other barriers can impede the delivery of high‐quality cancer care to underserved patients. Patient navigation services represent one innovation for addressing perceived barriers to care encountered by disadvantaged patients. In this report, the authors have 1) defined patient navigation, distinguishing it from other cancer support services; 2) described how programs are organized; and 3) discussed the need for research on program effectiveness.METHODSInformation was examined on navigation programs published in the scientific literature and on line. Qualitative research also was conducted, consisting of direct observation of patient care in cancer clinics with and without navigators in northern California, in‐person interviews with personnel and patients in the clinics observed, and telephone interviews with navigators at four sites across the United States.RESULTSThe authors found that navigation services have been implemented at all stages of cancer care: prevention, screening, treatment, and survival. Navigators differ from other cancer support personnel in their orientation toward flexible problem solving to overcome perceived barriers to care rather than the provision of a predefined set of services. There are no rigorous demonstrations of the effects and effectiveness of navigation, although such studies are underway.CONCLUSIONSCurrently, patient navigation is understudied, and literature documenting its effects and effectiveness is scant. Rigorous studies are needed of the navigator role and program costs and benefits. Such studies will facilitate an assessment of program effectiveness, feasibility across a range of health care settings, and performance relative to alternative approaches for addressing barriers to care among the underserved. Cancer 2005. © 2005 American Cancer Society.
Numerical study of mixed freeway traffic flows
Authors: Xie Zhimin , Zhu Zuojin , Hu JunJian 
Published: July 2005

AbstractThis study presents some features in the numerical modelling of multi‐class mixed freeway traffic described by extended LWR model. The evaluation of the eigenvalues and the right characteristic matrix of the mixed traffic system was reported in detail. To some extent, this is the key step in the application of the second‐order symmetrical total variation diminishing (TVD) numerical method to traffic modelling. Examples for four‐class mixed traffic flows were given to illustrate the solution feasibility. It was found that, when the global density wave keeps the same form, the variation of vehicular composition in the initial density wave has no effect on the mean speed of propagation of traffic wave on freeways, but can affect the decay rate of the density wave in different way. Traffic mixing and the impedance of the slow moving vehicles are reasons of the small amplitude density oscillations downstream the main global density wave. Copyright © 2005 John Wiley & Sons, Ltd.
Unexpected Behaviour of Pyridine‐2‐carbaldehyde Thiosemicarbazonatocopper(II) Entities in Aqueous Basic Medium – Partial Transformation of Thioamide into Nitrile
Authors: Gómez‐Saiz Patricia , Gil‐García Rubén , Maestro Miguel A. , Pizarro José Luis , Arriortua María Isabel , Lezama Luis , Rojo Teófilo , García‐Tojal Javier 
Published: July 2005

AbstractUnusual species are obtained from the HL/CuII/NO3– system (HL = pyridine‐2‐carbaldehyde thiosemicarbazone) in basic aqueous solutions. A partial desulfurization process occurs for 1:1 Cu/HL molar ratio which gives rise to the precipitation of the mixed ligand [Cu(L)(LCN)] (1) complex [HLCN = C7H6N4, (pyridin‐2‐ylmethylene)hydrazinecarbonitrile]. This compound contains CuII ions in a square‐pyramidal environment. On the other hand, distorted octahedral [Cu(L)2] (2) entities are isolated in excess of the thiosemicarbazone ligand. Desulfurization of the thiosemicarbazone is detected even at physiological pH values. However, this reaction does not take place in absence of CuII ions, and HL·2.25H2O (3) or HL·H2O are obtained in these conditions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
First Propargyl Azides Bearing Strong Acceptor Substituents and Their Effective Conversion into Allenyl Azides: Influence of the Electronic Effects of Substituents on the Reactivity of Propargyl Azides
Authors: Fotsing Joseph Rodolph , Banert Klaus 
Published: July 2005

AbstractWe have succeeded in the synthesis of propargyl azides containing 1‐ or 3‐phenylthio functionalities. The selective oxidation of their sulfur atoms to sulfoxides and sulfones allows access to the first propargyl azides bearing acceptor substituents. Interestingly, the prototropic rearrangement of the latter propargyl azides leads to the formation of allenyl azides with relatively high stabilities and with moderate to good yields. Propargyl azides containing phenylthio functionalities react in the presence of nucleophiles to afford the expected N‐unsubstituted 1,2,3‐triazoles via short‐lived allenyl azides. These results are entirely different from those of the corresponding sulfoxides and sulfones, which react under the analogous conditions either to produce the corresponding bis(triazolo)pyrazine derivatives or to yield newly substituted vinyl azides. The latter compounds can successfully be used as starting material providing access to azirines. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
A Concise Synthesis of Trifluoromethylated Cyclohexenones: A One‐Pot, Five‐Step Domino Reaction
Authors: Christophe Carole , Billard Thierry , Langlois Bernard R. 
Published: July 2005

Abstractβ‐Trifluoromethylated aromatic enones can undergo, in one pot, a five‐step domino process leading, with good yields, to 5‐trifluoromethylated cyclohexenones that constitute valuable functionalized fluorinated building‐blocks. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Neural substrates for functionally discriminating self‐face from personally familiar faces
Authors: Platek Steven M. , Loughead James W. , Gur Ruben C. , Busch Samantha , Ruparel Kosha , Phend Nicholas , Panyavin Ivan S. , Langleben Daniel D. 
Published: July 2005

AbstractUnderstanding the neurobiological substrates of self‐recognition yields important insight into socially and clinically critical cognitive functions such as theory of mind. Experimental evidence suggests that right frontal and parietal lobes preferentially process self‐referent information. Recognition of one's own face is an important parameter of self‐recognition, but well‐controlled experimental data on the brain substrates of self‐face recognition is limited. The goal of this study was to characterize the activation specific to self‐face in comparison with control conditions of two levels of familiarity: unknown unfamiliar face and the more stringent control of a personally familiar face. We studied 12 healthy volunteers who made “unknown,” “familiar,” and “self” judgments about photographs of three types of faces: six different novel faces, a personally familiar face (participant's fraternity brother), and their own face during an event‐related functional MRI (fMRI) experiment. Contrasting unknown faces with baseline showed activation of the inferior occipital lobe, which supports previous findings suggesting the presence of a generalized face‐processing area within the inferior occipital‐temporal region. Activation in response to a familiar face, when contrasted with an unknown face, invoked insula, middle temporal, inferior parietal, and medial frontal lobe activation, which is consistent with an existing hypothesis suggesting familiar face recognition taps neural substrates that are different from those involved in general facial processing. Brain response to self‐face, when contrasted with familiar face, revealed activation in the right superior frontal gyrus, medial frontal and inferior parietal lobes, and left middle temporal gyrus. The contrast familiar vs. self produced activation only in the anterior cingulate gyrus. Our results support the existence of a bilateral network for both perceptual and executive aspects of self‐face processing that cannot be accounted for by a simple hemispheric dominance model. This network is similar to those implicated in social cognition, mirror neuron matching, and face‐name matching. Our findings also show that some regions of the medial frontal and parietal lobes are specifically activated by familiar faces but not unknown or self‐faces, indicating that these regions may serve as markers of face familiarity and that the differences between activation associated with self‐face recognition and familiar face recognition are subtle and appear to be localized to lateral frontal, parietal, and temporal regions. Hum. Brain Mapping, 2005. © 2005 Wiley‐Liss, Inc.
Xanthone Receptors as Oxyanion‐Hole Mimics in Artificial Enzymes
Authors: Simón Luis , Muñiz Francisco M. , Sáez Silvia , Raposo César , Sanz Francisca , Morán Joaquín R. 
Published: July 2005

AbstractDifferent xanthone‐based receptors (2–10) for lactones and lactams have been prepared, and the feasibility of these compounds to mimic the known enzymatic ‘oxyanion‐hole’ structure is discussed. The self‐association of the receptors was found to pose a serious drawback for complex formation. X‐Ray crystal structures of receptor dimers allowed us to understand the reasons for their self‐association and to improve the design of the catalysts. The catalytic activity of the receptors has been tested towards the nucleophilic addition of pyrrolidine to unsaturated lactones. Since the resulting complexes were very weak in organic solvents, new receptors were developed for lactams, which showed better stabilities, and their catalytic activities were studied.
First [4+2] Cycloadditions Involving the Olefinic Bond of an ‘Aldoketeniminium Salt’ (=N‐Alk‐1‐enylideneaminium Salt)
Authors: Mahuteau‐Betzer Florence , Ding Ping‐Yu , Ghosez Léon 
Published: July 2005

Abstract‘Keteniminium triflates’ (=N‐alk‐1‐enylideneaminium trifluoromethanesulfonates; [MeN(Ts)CHC NR1(R2)]+TfO−) generated in situ from Nα‐tosylsarcosinamides MeN(Ts)CH2CONR1(R2) unexpectedly react with cyclopenta‐1,3‐diene and cyclohexa‐1,3‐diene to give Diels–Alder reactions across the CC bond of the cumulene. The use of Nα‐tosylsarcosinamides derived from chiral pyrrolidines allows the direct preparation of trinorbornenone derivative 6 in high enantiomer purity.
The interaction of selected semiconducting biomaterials with platelet‐rich plasma and whole blood
Authors: Shih Chun‐Che , Shih Chun‐Ming , Su Yea‐Yang , Gerhardt Rosario A. , Lin Shing‐Jong 
Published: July 2005

AbstractCopper and silicon are used as biomaterials in various forms. Silicon is a well‐known semiconductor and has two distinct types (n‐type and p‐type), depending on the dopants used. The oxides (e.g., CuO and Cu2O) on the copper surface also behave as semiconductors. The electrochemical properties of these two selected semiconducting biomaterials were investigated by cyclic voltammetry, electrochemical impedance spectroscopy (EIS), and open‐circuit potential (OCP) in an aerated Ringer's solution at 37°C. Platelet‐rich plasma (PRP) and whole blood from a healthy human donor were used to determine the degree of interaction with the selected semiconducting materials in vitro. Morphologies of adherent platelets and blood on these two biomaterials were examined by scanning electron microscopy (SEM). Experimental results indicated that the degree of interaction is a function of the electrochemical properties of these two biomaterials. Platelets and blood were found to react strongly with p‐type biomaterials while little or no sign of interaction with n‐type biomaterials was demonstrated. The difference in PRP and whole blood reactions between p‐type and n‐type semiconductors was quantified to be significant as p < 0.05. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Controlled copolymerization of vinyl acetate with 1‐alkenes and their fluoro derivatives by degenerative transfer
Authors: Borkar Sachin , Sen Ayusman 
Published: July 2005

AbstractThe degenerative transfer copolymerization of vinyl acetate with ethene and higher 1‐alkenes, as well as their fluoro derivatives (RfCHCH2), under mild conditions was carried out using AIBN as the initiator and ethyl iodoacetate as the control agent. The obtained random copolymers were fairly high in alkene content, with high molecular weights and relatively narrow polydispersities. The quasi‐living nature of the copolymerization allowed the synthesis of a block terpolymer by sequential addition of two different 1‐alkene comonomers to a vinyl acetate copolymerization system. The fluorinated side chains of vinyl acetate/fluoro alkene copolymers segregate toward the air‐side of thin films, resulting in advancing water contact angle as high as 114°. 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3728–3736, 2005
Stabilizer‐free dispersion copolymerization of maleic anhydride and vinyl acetate. I. Effects of principal factors on microspheres
Authors: Xing Chang‐Min , Yang Wan‐Tai 
Published: July 2005

AbstractA novel dispersion copolymerization of maleic anhydride (MAn) and vinyl acetate (VAc) without adding stabilizer is developed, which gives uniform copolymer microspheres with tunable sizes. Some principal factors affecting the microspheres, such as reaction time, monomer concentration and feed ratio, reaction media, and cosolvent, were investigated. It was found that the stabilizer‐free dispersion copolymerization of MAn and VAc is a rapid process, and the particle size grows in accordance with the evolution of polymerization. The chemical composition of the copolymer microspheres was characterized by FT‐IR and 13C NMR spectroscopies. Over a wide range of monomer concentrations, the microspheres can always be formed and stably dispersed, with uniform sizes ranging from 180 nm to 740 nm. The yield of copolymer microspheres reaches a maximum at 1:1 feed ratio of MAn to VAc, owing to the alternating copolymerization between the binary monomers by a known charge‐transfer‐complex mechanism. However, the diameter of microspheres drastically increases when MAn content is enhanced. Only some specific alkyl ester solvents, such as n‐butyl acetate, isobutyl acetate, n‐amyl acetate, are desirably fit for this unique stabilizer‐free dispersion polymerization. Furthermore, we found that when some acetone is added as a cosolvent, the copolymer microspheres can still be formed, with much larger diameters. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3760–3770, 2005
Copolyimides containing alicyclic and fluorinated groups: Solubility and gas separation properties
Authors: Bas Corine , Mercier Régis , Sanchez‐Marcano José , Neyertz Sylvie , Albérola N. Dominique , Pinel Eliette 
Published: July 2005

AbstractA series of polyimides with alicyclic and fluorinated moieties previously synthesized were studied for gas separation applications. The solubility behavior of polyimides in various solvents was analyzed through the solubility parameter approach. Permeability coefficients and ideal selectivities were determined for common gases, that is, He, H2, O2, and N2. Polyimide permeabilities were correlated to an improvement of the soluble character and were increased by the introduction of both alicyclic and fluorinated structures. The effect of the casting solvent on gas separation properties was also pointed out. It was found that it is enhanced with increasing diameters for the gas molecules. Finally, some correlations between permeability coefficients and microstructural parameters were discussed. The probability of correlation appears to be also dependent on the diameter and on the polarizability of the gas molecule. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2413–2426, 2005.
Herbicidal cyanoacrylates with antimicrotubule mechanism of action
Authors: Tresch Stefan , Plath Peter , Grossmann Klaus 
Published: July 2005

AbstractThe herbicidal mode of action of the new synthetic cyanoacrylates ethyl (2Z)‐3‐amino‐2‐cyano‐4‐ethylhex‐2‐enoate (CA1) and its isopropyl ester derivative CA2 was investigated. For initial characterization, a series of bioassays was used indicating a mode of action similar to that of mitotic disrupter herbicides such as the dinitroaniline pendimethalin. Cytochemical fluorescence studies including monoclonal antibodies against polymerized and depolymerized tubulin and a cellulose‐binding domain of a bacterial cellulase conjugated to a fluorescent dye were applied to elucidate effects on cell division processes including mitosis and microtubule and cell wall formation in maize roots. When seedlings were root treated with 10 µM of CA1 or CA2, cell division activity in meristematic root tip cells decreased within 4 h. The chromosomes proceeded to a condensed state of prometaphase, but were unable to progress further in the mitotic cycle. The compounds caused a complete loss of microtubular structures, including preprophase, spindle, phragmoplast and cortical microtubules. Concomitantly, in the cytoplasm, an increase in labelling of free tubulin was observed. This suggests that the herbicides disrupt polymerization and microtubule stability, whereas tubulin synthesis or degradation appeared not to be affected. In addition, cellulose labelling in cell walls of root tip cells was not influenced. The effects of CA1 and CA2 were comparable with those caused by pendimethalin. In transgenic Arabidopsis plants expressing a green fluorescent protein‐microtubule‐associated protein4 fusion protein, labelled arrays of cortical microtubules in living epidermal cells of hypocotyls collapsed within 160 min after exposure to 10 µM CA1 or pendimethalin. Moreover, a dinitroaniline‐resistant biotype of goosegrass (Eleusine indica (L) Gaertn) with a point mutation in α‐tubulin showed cross‐resistance against CA1 and CA2. The results strongly indicate that the cyanoacrylates are a new chemical class of herbicide which possess the same antimicrotubule mechanism of action as dinitroanilines, probably including interaction with the same binding site in α‐tubulin. Copyright © 2005 Society of Chemical Industry