bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alumina‐supported microwave synthesis of Cassia marginata seed gum‐graft‐polyacrylamide
Authors: Singh V. , Kumari P. L. , Tiwari A. , Pandey S. 
Published: May 2010

AbstractIn this article, we report the alumina‐supported, microwave (MW)‐induced synthesis of Cassia marginata seed gum‐graft‐polyacrylamide (MWS‐GP). No initiator or catalyst was required in the synthesis, and the conditions for the grafting were optimized by variation of the acrylamide concentration, MW power, and exposure time. At an identical monomer concentration, a higher level of grafting was observed in the solid‐supported method than under aqueous conditions (the MW‐assisted or redox‐initiated thermal method). The used alumina support was easily separated from MWS‐GP and reused for another three cycles without any significant loss in its efficiency as a solid support. MWS‐GP synthesized under optimum conditions was characterized with Fourier transform infrared spectroscopy, 13C‐NMR, thermogravimetric analysis, and X‐ray diffraction, with C. marginata gum as a reference. The properties of MWS‐GP and its saponified derivative were studied to explore the applicability areas of the copolymer in hydrogel formation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of vanillin on the miscibility of poly(vinyl alcohol)/gelatin composite hydrogel: Physical and chemical properties
Authors: Cheng Lin , Zuo Yi , Zou Qin , Li Junfeng , Wang Huanan , Shen Juan , Jiang Hong , Wang Li , Li Yubao 
Published: May 2010

AbstractA composite based on poly(vinyl alcohol) (PVA) and gelatin (Gel) was prepared in the form of a miscible interphase by freezing‐thawing method using vanillin as a new compatilizer. The chemical and physical properties of PVA/Gel/vanillin composite hydrogels with different reagent concentration, and reaction time were investigated using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), tensile testing, and scanning electron microscopy (SEM). The results elicit that the formation of CN Schiff base between Gel and vanillin may break the intrahydrogen bonding of Gel. Proper reaction time and more interactive groups result in optimal interhydrogen bonding between modified Gel and PVA so that the miscibility between two polymers has been improved. In addition, the PVA/Gel/V composite with the vanillin concentration of 0.20 g/mL and 2 h stirring exhibits a better compatibility and a higher tensile strength, which can be tailored for potential use in cartilage tissue engineering. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
A novel amide–imide copolymer as a matrix resin for ultraviolet photoresists: Preparation, properties, and application
Authors: Liu Jian‐Guo , Li Ping , Liu He‐Ping , Zheng Jia‐Shen 
Published: May 2010

AbstractThe matrix resin as the backbone material plays a crucial role in the performance of a photoresist. In this study, a novel amide–imide copolymer, poly[N‐(p‐hydroxyphenyl) methacrylamide‐co‐N‐phenylmaleimide], was successfully prepared. This copolymer was very close to 1 : 1 (molar ratio) in composition and was predominately alternating in structure during the copolymerization with an equimolar monomer feed ratio. It had good solubility in organic solvents and good film‐forming characteristic, and it was also soluble in a basic aqueous solution. Differential scanning calorimetry and thermogravimetric analyses showed that it had a glass‐transition temperature at about 290°C and excellent thermostability. Photolithographic experiments indicated that the UV photoresist formulated with this copolymer as a matrix resin, diazonaphthoquinone sulfonate as a photosensitizer, a solvent, and other additives had a resolution of about 1 μm, a contrast of 2.83, and a sensitivity of 28 mJ/cm2. This photoresist had good plasma etching resistance and could endure 260°C for 30 min without thermal deformation of the lithographic images. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Adsorption selectivity and dynamic adsorption behaviors of Cu(II), Ag(I), and Au(III) on silica gel encapsulated by amino functionalized polystyrene
Authors: Xu Qiang , Yin Ping , Zhao Guifang , Sun Yanzhi , Qu Rongjun 
Published: May 2010

AbstractAdsorption of precious metal ions from aqueous solutions has earned great concern recently due to environmental protection factor and the value of precious metals. In this article, a novel adsorbent silica gel microspheres encapsulated by amino functionalized polystyrene (SG‐PS‐NH2) has been synthesized, and the adsorption selectivity and the dynamic adsorption properties of SG‐PS‐NH2 for Cu(II), Ag(I), and Au(III) has been investigated. The results displayed that SG‐PS‐NH2 had excellent adsorption for Au(III)/Ag(I) in binary ion systems, especially in the systems of Au(III)‐Zn (II), Au(III)‐Ni(II), and Ag(I)‐Zn(II). The dynamic adsorption showed that the adsorption capacities of SG‐PS‐NH2 for Cu(II), Ag(I), and Au(III) increased with the prolonging of contact time, and the affinity order of three metal ions adsorbed by of SG‐PS‐NH2 is Au(III) > Ag(I) > Cu(II), which is inversely correlated with their electronegativities. The regeneration capacities of SG‐PS‐NH2 were investigated by using the eluent solution of 0.5% thiourea in 1 mol/L HCl, and it is found that the changes of the adsorption capability are relatively small after several cycles of adsorption–desorption. Thus, silica gel encapsulated by polystyrene containing amino groups (SG‐PS‐NH2) is favorable and useful for the removal of precious metal ions because it is eco‐friendly and easier to reuse. The comparison of SG‐PS‐NH2 with other adsorbents suggests that SG‐PS‐NH2 have great potential applications in environmental protection and the recovery of precious metals. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and thermal stability of brominated natural rubber from latex
Authors: Xue Xinghua , Wu Yaohui , Wang Fengping , Ling Jun , Fu Xin 
Published: May 2010

AbstractThe effects of pH value of reaction system, reaction time, reaction temperature, bromine concentration, and amount of potassium persulfate on the bromination reaction in the preparation of brominated natural rubber (BNR) from natural rubber latex were discussed. It has been found from the thermal analysis, that is, the thermal degradation of BNR in nitrogen is a two‐step reaction, and 16% carbonide with a stable structure remained at 470–650°C. The thermo‐oxidative degradation of BNR in air is also a two‐step reaction, and the percentage of degraded BNR reaches to nearly 100% at 600°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Lanthanide (Eu3+, Tb3+) Centered Mesoporous Hybrids with 1,3‐Diphenyl‐1,3‐Propanepione Covalently Linking SBA‐15 (SBA‐16) and Poly(methylacrylic acid)
Authors: Li Ya‐Juan , Yan Bing , Li Ying 
Published: May 2010

Abstract1,3‐Diphenyl‐1,3‐propanepione (DBM)‐functionalized SBA‐15 and SBA‐16 mesoporous hybrid materials (DBM‐SBA‐15 and DBM‐SBA‐16) are synthesized by co‐condensation of modified 1,3‐diphenyl‐1,3‐propanepione (DBM‐Si) and tetraethoxysilane (TEOS) in the presence of Pluronic P123 and Pluronic F127 as a template, respectively. The as‐synthesized mesoporous hybrid material DBM‐SBA‐15 and DBM‐SBA‐16 are used as the first precursor, and the second precursor poly(methylacrylic acid) (PMAA) is synthesized through the addition polymerization reaction of the monomer methacrylic acid. These precursors then coordinate to lanthanide ions simultaneously, and the final mesoporous polymeric hybrid materials Ln(DBM‐SBA‐15)3PMAA and Ln(DBM‐SBA‐16)3PMAA (Ln=Eu, Tb) are obtained by a sol‐gel process. For comparison, binary lanthanide SBA‐15 and SBA‐16 mesoporous hybrid materials (denoted as Ln(DBM‐SBA‐15)3 and Ln(DBM‐SBA‐16)3) are also synthesized. The luminescence properties of these resulting materials are characterized in detail, and the results reveal that ternary lanthanide mesoporous polymeric hybrid materials present stronger luminescence intensities, longer lifetimes, and higher luminescence quantum efficiencies than the binary lanthanide mesoporous hybrid materials. This indicates that the introduction of the organic polymer chain is a benefit for the luminescence properties of the overall hybrid system. In addition, the SBA‐15 mesoporous hybrids show an overall increase in luminescence lifetime and quantum efficiency compared with SBA‐16 mesoporous hybrids, indicating that SBA‐15 is a better host material for the lanthanide complex than mesoporous silica SBA‐16.
Long-term results of gastrectomy for α-fetoprotein-producing gastric cancer
Authors: Inoue M , Sano T , Kuchiba A , Taniguchi H , Fukagawa T , Katai H 
Published: May 2010

Abstract

Background
α-Fetoprotein (AFP)-producing gastric cancer is a rare tumour. It is said to have a high incidence of liver metastasis and poor prognosis. This study sought to evaluate long-term outcomes in such patients.

Methods
Records of consecutive patients with gastric carcinoma who underwent preoperative measurement of serum AFP levels and gastrectomy were reviewed to identify those who satisfied the following criteria: preoperative AFP level exceeding 40 ng/ml with a decrease after gastrectomy, or raised preoperative AFP level (10–39 ng/ml) and resected tumour showing histologically characteristic features or immunohistochemically positive AFP production.

Results
Of 3374 patients with gastric cancer, 53 (1·6 per cent) met the selection criteria. Tumours were characterized by a high incidence of nodal (79 per cent) or liver (53 per cent) metastasis. Preoperative serum AFP levels showed no correlation with tumour size, depth of invasion, disease stage or survival. The 5-year survival rate was 34 per cent. Five patients survived after recurrence following multimodal treatment. A rising AFP level during follow-up always led to tumour recurrence, but the level remained normal in 11 of 31 patients with recurrence.

Conclusion
AFP-producing tumours represent a small subgroup of gastric cancer with high metastatic potential. Postoperative serum AFP level can help predict recurrence but a normal level does not mean absence of recurrence. Prognosis is not as poor as previously thought, and multimodal treatment may be worthwhile even in patients with recurrent tumour.
Minor Enantiomer Recycling—Effect of Two Reinforcing Catalysts on Product Yield and Enantiomeric Excess
Authors: Fransson Linda , Laurell Anna , Widyan Khalid , Wingstrand Erica , Hult Karl , Moberg Christina 
Published: May 2010

AbstractKinetic modeling of a recycling procedure in which the minor product enantiomer from an enantioselective catalytic reaction is selectively retransformed to starting material by a second chiral catalyst demonstrates that the enantiomeric excess of the product is not affected by the relative amounts of the two catalysts, but that the yield increases when the amount of the catalyst for the product‐forming reaction is increased. The yield, but not the enantiomeric excess, is also affected by the initial substrate concentration. The recycling process is compared to sequential processes in which either the second catalyst is added after completion of the first reaction or in which the two catalysts are added simultaneously. In the sequential processes, high enantioselectivity can be obtained at the expense of product yield, whereas under recycling conditions both high enantiomeric excess and high yield can be achieved. Experimental data from a recycling procedure providing qualitative support for results from kinetic modeling are presented.
Voltammetric Characterization of Redox‐Inactive Guest Binding to LnIII[15‐Metallacrown‐5] Hosts Based on Competition with a Redox Probe
Authors: Jankolovits Joseph , Kampf Jeff W. , Maldonado Stephen , Pecoraro Vincent L. 
Published: May 2010

AbstractA novel competitive binding assay was implemented to monitor the binding of a redox inactive substrate to a redox inactive metallacrown host based on its competition with ferrocene carboxylate (FcC−) using cyclic voltammetry (CV). First, the binding of FcC− to LnIII[15‐MC‐5] (LnMC) hosts was characterized by cyclic voltammetry. It was shown that the voltammetric half wave potentials, E1/2, shifted to more positive potentials upon the addition of LnMC. The explicit dependence of E1/2 with the concentration of LnMC was used to determine the association constants for the complex. The FcC− binding strength decreased with larger central lanthanide metals in the LnMC hosts, and substantially weaker binding was observed with LaIII. X‐ray crystallography revealed that the hydrophobic host cavity incompletely encapsulated FcC− when the guest was bound to the nine‐coordinate LaIII, suggesting the LnMC’s ligand side chains play a substantial role in guest recognition. With knowledge of the MC‐FcC− solution thermodynamics, the binding affinity of a redox inactive guest was then assessed. Addition of sodium benzoate to a LnMC and FcC− mixture resulted in E1/2 shifting back to the value observed for FcC− in the absence of LnMC. The association constants between benzoate and LnMC’s were calculated via the competitive binding approach. Comparison with literature values suggests this novel assay is a viable method for determining association constants for host–guest systems that exhibit the proper electrochemical behavior. Notably, this CV competitive binding approach does not require the preparation of a modified electrode or a tethered guest, and thus can be generalized to a number of host–guest systems.
Fluorinated Glycosyl Amino Acids for Mucin‐Like Glycopeptide Antigen Analogues
Authors: Wagner Sarah , Mersch Christian , Hoffmann‐Röder Anja 
Published: May 2010

AbstractThe aberrant glycosylation profiles of mucin glycoproteins on epithelial tumour cells represent attractive target structures for the development of immunotherapy against cancer. Mucin‐type glycopeptides have been successfully investigated as molecularly defined vaccine prototypes for triggering humoral immunity but are susceptible to rapid in vivo degradation. As a potential means to enhance the bioavailabilities of the antigenic structures, hydrolysis‐resistant carbohydrate analogues with fluorine substituents at positions C6, C2′ and C6′ were synthesised and incorporated into the tandem repeat sequence of the mucin MUC1. The resulting pseudo‐glycopeptides can be used to elucidate the effects of chemically modified antibody determinants on metabolic and immunological properties.
DFT Mechanistic Study on Diene Metathesis Catalyzed by Ru‐Based Grubbs–Hoveyda‐Type Carbenes: The Key Role of π‐Electron Density Delocalization in the Hoveyda Ligand
Authors: Solans‐Monfort Xavier , Pleixats Roser , Sodupe Mariona 
Published: May 2010

AbstractThe catalytic activity and catalyst recovery of two heterogenized ruthenium‐based precatalysts (H and NO2(4)) in diene ring‐closing metathesis have been studied by means of density functional calculations at the B3LYP level of theory. For comparison and rationalization of the key factors that lead to higher activities and higher catalyst recoveries, four other Grubbs–Hoveyda complexes have also been investigated. The full catalytic cycle (catalyst formation, propagation, and precatalyst regeneration) has been considered. DFT calculations suggest that either for the homogeneous and heterogenized systems the activity of the catalysts mainly depends on the ability of the precursor to generate the propagating carbene. This ability does not correlate with the traditionally identified key factor, the Ru⋅⋅⋅O interaction strength. In contrast, precatalysts with lower alkoxy‐dissociation energy barriers and lower stabilities compared with the propagating carbene also present larger C1C2 bond length (i.e., lower π character of the CC bond that exists between the metal–carbene (RuC) and the phenyl ring of the Hoveyda ligand). Catalyst recovery, regardless of whether a release–return mechanism occurs or not, is also mainly determined by the π delocalization. Therefore, future Grubbs–Hoveyda‐type catalyst development should be based on fine‐tuning the π‐electron density of the phenyl moiety, with the subsequent effect on the metalloaromaticity of the ruthenafurane ring, rather than considering the modification of the Ru⋅⋅⋅O interaction.
Synthesis, Structure and Molecular Recognition of Functionalised Tetraoxacalix[2]arene[2]triazines
Authors: Wang Qi‐Qiang , Wang De‐Xian , Yang Hai‐Bo , Huang Zhi‐Tang , Wang Mei‐Xiang 
Published: May 2010

AbstractFunctionalised dialkoxy‐substituted tetraoxacalix[2]arene[2]triazine macrocycles 6 have been readily synthesised by the fragment coupling approach using methyl 3,5‐dihydroxy‐4‐alkoxybenzoates and cyanuric chloride as the starting materials under very mild conditions. AlCl3‐mediated deallylation and debenzylation reactions afforded the lower‐rim dihydroxy‐substituted tetraoxacalix[2]arene[2]triazine derivatives 11 and 13 in good yields. Although dialkoxy‐substituted tetraoxacalix[2]arene[2]triazine macrocycles are fluxional in solution on the NMR spectroscopy timescale, they adopt a symmetric or slightly distorted 1,3‐alternate conformation with the bridging oxygen atoms conjugated with the triazine rings. The dihydroxylated tetraoxacalix[2]arene[2]triazine 13 b, which gives a mixture of monomer and dimer in solution according to a diffusion NMR spectroscopy study, adopts a 1,3‐alternate conformation and forms a cyclic tetrameric assembly in the solid state due to the formation of intermolecular hydrogen‐bonding networks. This dihydroxylated macrocyclic host molecule, a hydrogen‐bond donor macrocycle with a V‐shaped cleft, interacts with 2,2′‐bipyridine, 4,4′‐bipyridine and 1,10‐phenanthroline guests. Although in solution they form the corresponding 1:1 complexes with binding constants ranging from 37.7 to 213 M−1, 2:2 host–guest complexes were observed in the crystalline state. Hydrogen‐bonding interactions, along with other non‐covalent interactions, such as lone‐pair‐electron–π and CH⋅⋅⋅π interactions, were found to be the driving force for the formation of host–guest complexes.
Phenakite‐Type BeP2N4—A Possible Precursor for a New Hard Spinel‐Type Material
Authors: Pucher Florian J. , Römer S. Rebecca , Karau Friedrich W. , Schnick Wolfgang 
Published: May 2010

AbstractBeP2N4 was synthesized in a multi‐anvil apparatus starting from Be3N2 and P3N5 at 5 GPa and 1500 °C. The compound crystallizes in the phenakite structure type (space group R$\bar 3$, no. 148) with a=1269.45(2) pm, c=834.86(2) pm, V=1165.13(4)×106 pm³ and Z=18. As isostructural and isovalence‐electronic α‐Si3N4 transforms into β‐Si3N4 at high pressure and temperature, we studied the phase transition of BeP2N4 into the spinel structure type by using density functional theory calculations. The predicted transition pressure of 24 GPa is within the reach of today’s state of the art high‐pressure experimental setups. Calculations of inverse spinel‐type BeP2N4 revealed this polymorph to be always higher in enthalpy than either phenakite‐type or spinel‐type BeP2N4. The predicted bulk modulus of spinel‐type BeP2N4 is in the range of corundum and γ‐Si3N4 and about 40 GPa higher than that of phenakite‐type BeP2N4. This finding implies an increase in hardness in analogy to that occurring for the β‐ to γ‐Si3N4 transition. In hypothetical spinel‐type BeP2N4 the coordination number of phosphorus is increased from 4 to 6. So far only coordination numbers up to 5 have been experimentally realized (γ‐P3N5), though a sixfold coordination for P has been predicted for hypothetic δ‐P3N5. We believe, our findings provide a strong incentive for further high‐pressure experiments in the quest for novel hard materials with yet unprecedented structural motives.
Pseudohalonium Ions: [Me3Si–X–SiMe3]+ (X=CN, OCN, SCN, and NNN)
Authors: Schulz Axel , Villinger Alexander 
Published: May 2010

AbstractBy utilizing reaction mixtures, such as Me3Si–X/[Me3Si–X–SiMe3]+ (X=CN, OCN, SCN, and NNN), it was possible to prepare the first examples of bissilylated pseudohalonium cations in high yields. The structure and bonding of a whole series of salts containing pseudohalonium cations is discussed on the basis of experimentally observed (X‐ray diffraction, Raman, and IR spectroscopy, and mass spectrometry) and theoretically obtained data. Salts containing pseudohalonium cations are only stable in the presence of weakly coordinating anions, such as the well‐known tetrakis(pentafluorophenyl)borate, [B(C6F5)4]−.
A New Highly Versatile Handle for Chemistry on a Solid Support: The Pipecolic Linker
Authors: Zajdel Paweł , Nomezine Gaël , Masurier Nicolas , Amblard Muriel , Pawłowski Maciej , Martinez Jean , Subra Gilles 
Published: May 2010

AbstractThe design, synthesis, and potential application of the pipecolic linker is presented. This new versatile handle can immobilize primary, secondary, and aromatic amines, as well as alcohols, phenols, and hydrazides, on a solid support. Compared with other linkers, the anchoring step is easy and efficient. The release of final products from the resin proceeds upon acidic treatment with high purities. The pipecolic linker offers the promise of being using in peptide chemistry to produce peptides modified at the N and C terminus, peptidomimetics, as well as small organic molecules.
Solution‐Processable Flower‐Shaped Hierarchical Structures: Self‐Assembly, Formation, and State Transition of Biomimetic Superhydrophobic Surfaces
Authors: Yin Jie , Yan Jing , He Min , Song Yanlin , Xu Xiaoguang , Wu Kai , Pei Jian 
Published: May 2010

AbstractSuperhydrophobic surfaces inspired by biological microstructures attract considerable attention from researchers because of their potential applications. In this contribution, two kinds of microscale flower‐shaped morphologies with nanometer petals formed from the hierarchical self‐assembly of benzothiophene derivatives bearing long alkyl chains have been developed as superhydrophobic surfaces. The intermediate stages of the assemblies demonstrated a new formation mechanism for such flower‐shaped morphologies. The hierarchical morphologies of the film exhibited excellent water‐repelling characteristics as superhydrophobic surfaces, which were prepared by means of a simple solution process. The transition process from the Cassie state to Wenzel state was easily realized owing to the slight microstructural differences in the two kinds of flowers caused by their different chemical structures. The superhydrophobicity of such functional materials might be beneficial for applications in electrical devices in which the presence of water would influence their performance.
ChemInform Abstract: La2Pb(SiS4)2.
Authors: Gulay L. D. , Daszkiewicz M. , Ruda I. P. , Marchuk O. V. 
Published: May 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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: Ba2Gd2(Si4O13): A Silicate with Finite Si4O13 Chains.
Authors: Wierzbicka‐Wieczorek Maria , Kolitsch Uwe , Tillmanns Ekkehart 
Published: May 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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 Strong Second‐Harmonic Generation Material Cd4BiO(BO3)3 Originating from 3‐Chromophore Asymmetric Structures.
Authors: Zhang Wei‐Long , Cheng Wen‐Dan , Zhang Hao , Geng Lei , Lin Chen‐Sheng , He Zhang‐Zhen 
Published: May 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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.