bluuebunny/crossref_metadata_2025 huggingface dataset:
Antiguan Methodism and Antislavery Activity: Anne and Elizabeth Hart in the Eighteenth-Century Black Atlantic
Authors: Saillant John
Published: April 2006

Around 1790, two young sisters born into a slaveholding free black family began instructing Antiguan slaves in literacy and Christianity. The sisters, Anne (1768–1834) and Elizabeth (1771–1833) Hart, first instructed their father's slaves at Popeshead—he may have hired them out rather than using them on his own crops—then labored among enslaved women and children in Antiguan plantations and in towns and ports like St. John's and English Harbour. Soon the sisters came to write about faith, slavery, and freedom. Anne and Elizabeth Hart were moderate opponents of slavery, not abolitionists but meliorationists. When compared to their black American, British, and West African contemporaries, the Hart sisters illuminate the birth of a black antislavery Christianity in the late eighteenth century precisely because they never became abolitionists. The Hart sisters shared with their black contemporaries a vivid sense of racial identity and evangelical Christianity. Yet as meliorationists, the Hart sisters did not oppose slavery as an institution, but rather the vice it spread into the lives of blacks. The difference between the Hart sisters and their contemporaries such as Richard Allen, Quobna Ottobah Cugoano, Olaudah Equiano, Lemuel Haynes, and John Marrant—all luminaries of black abolitionism of the late eighteenth and early nineteenth centuries—was that the abolitionists felt themselves citizens of a modern nation-state characterized by power that could be used against slave traders and slaveholders. The Hart sisters never thought of themselves as citizens and abjured political means, including revolution, of ending slavery. This essay aims to describe the Hart sisters' faith and antislavery activity and to analyze the difference between meliorationism and abolitionism in terms of a black writer's ability or inability to identify as a citizen of a modern nation-state.
Analysis of zone and pump configurations in simulated moving bed purification of insulin
Authors: Chin Chim Yong , Xie Yi , Alford Joseph S. , Wang Nien‐Hwa Linda
Published: April 2006

The effects of pump failures in nine zone and pump configurations for the size‐exclusion simulated moving bed purification of insulin are analyzed. Simulations based on verified intrinsic parameters are used to understand the dynamic wave phenomena. This understanding helps determine the best zone and pump configuration, determine the time window to recover from the degraded state, and formulate contingency responses to failures. The results show that the open‐loop three‐zone simulated moving bed is the best. It is more reliable, and has higher productivity and reduced residence time of the high molecular weight impurities. A disadvantage of the three‐zone is the higher solvent consumption. In the recommended configuration: desorbent pump failure is critical and dual redundant pumps are recommended; feed pump failure is marginal and results in diluted product; and zone II pump failure is critical—the time window for corrective action is half a step‐time. Zone pumps are recommended instead of outlet pumps because they do not result in stationary phase collapse from high pressure drop and allow higher productivity in pressure‐limited systems. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Variation of inhibited oxidation parameters in polyethylene melting
Authors: Shlyapnikov Yury A. , Kolesnikova Natalya N.
Published: April 2006

The oxidation of low‐density polyethylene by molecular oxygen was studied in the temperature range 80–210°C. In the curves of temperature dependence of several parameters of inhibited oxidation, breaks were observed at the melting temperature, near 110°C. At this temperature, the preexponential factor calculated from the temperature dependence of the rate constant of inhibitor consumption changed 105 times, sharply increasing at the transition from the polymer melt to the solid polymer. This indicated that an essential difference existed between the properties of the intercrystalline amorphous polymeric substance and the completely molten one. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 978–981, 2006
Crystallization behavior of PA66/SiO2 organic‐inorganic hybrid material
Authors: Wang Hua‐Lin , Shi Tie‐Jun , Yang Shan‐Zhong , Zhai Lin‐Feng , Hang Guo‐Pei
Published: April 2006

The poly 2‐hydroxy propylmethacrylate‐methyl methacrylate (PHPMA‐MMA)/SiO2 composite, derived from 2‐hydroxy propylmethacrylate (HPMA), methyl methacrylate (MMA), and tetraethoxysilane (TEOS), was used to synthesize polyamide 66(PA66)/SiO2 organic‐inorganic hybrid material. X‐ray diffraction (XRD) was used to investigate the lattice spacing change of the PA66/SiO2 hybrid material. It was found that the addition of PHPMA‐MMA/SiO2 composite nearly did not change the crystal form of PA66. The nonisothermal crystallization kinetics of PA66 and PA66/SiO2 hybrid material was investigated by differential scanning calorimetry (DSC) with various cooling rates. At every given cooling rate, the start crystallization temperature of the PA66/SiO2 hybrid material was higher than that of PA66, while the crystallization temperature range was narrower than that of PA66. Avrami analysis modified by the Jeziorny method, the Ozawa method, and a method developed by Liu were employed to describe the nonisothermal crystallization process of the samples. The results showed that the Jeziorny method and the Ozawa method were not suitable to describe the nonisothermal crystallization process of PA66/SiO2 hybrid material; however, when the relative degree of crystallinity X (t) was less than 1 − 1/e, ln [− ln (1 − X (t))] was still linear to lnt. The Liu method was successful to describe the nonisothermal crystallization processes for both PA66 and the PA66/SiO2 hybrid material. It was confirmed that the presence of PHPMA‐MMA/SiO2 composite could increase the crystallization rate and had a hetero phase nucleation effect on the PA66 matrix. Moreover, the introduction of PHPMA‐MMA/SiO2 could improve the crystallization active energy ▵E calculated by the Kissinger equation, attributing to the strong interaction between the polyamide chains and the PHPMA‐MMA/SiO2 composite. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 810–817, 2006
Effect of type of substitution in 4,4′‐bis‐(diaminodiphenyl) methane hardener on cure kinetics, mechanical, and flame retardant properties of tetrafunctional epoxy resins
Authors: Jagadeesh K. S. , Rao J. Gururaja
Published: April 2006

The nature of the substituent in 4,4′‐bis‐(diaminodiphenyl) methane (DDM) hardener on the cure kinetics, mechanical, and flame retardant properties of N,N,N′,N′‐tetraglycidyl diaminodiphenyl methane (TGDDM) resin is investigated in comparison with unsubstituted DDM and widely used 4,4′‐bis‐(diaminodiphenyl) sulfone hardeners. Dynamic differential scanning calorimetry (DSC) and cure rheology studies showed that the substitution decreased the reactivity of the amine. An electron‐withdrawing chlorine substituent was found to be more effective than an electron‐releasing methyl group in reducing the amine reactivity. Substituted and unsubstituted DDM hardeners showed two peaks in their DSC thermograms that were due to steric hindrance in the former and deficiency of amine in the latter. Substitution showed its effect on the mechanical properties and glass‐transition temperature. The flexural modulus was increased; however, the Izod impact and glass‐transition temperature were decreased in substituted amine systems. The limiting oxygen index results showed higher flame retardancy in the chlorine substituted hardener system compared to other hardener systems that were studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 480–491, 2006
Influence of copolymer's end groups and molecular weights on the rheological and thermomechanical properties of blends of novel thermoplastic copolymers and epoxy resins
Authors: Cicala G. , La Spina R. , Recca A. , Sturiale S.
Published: April 2006

In this paper, we present a study on the properties of epoxy resins blended with copolyethersulfones. Several copolyethersulphones were synthesized by varying the molecular weights and the end groups. The obtained thermoplastics were then mixed with diglycidyl ether of biphenol A (DGBEA) (15% wt ratio), cured with methylene bis(2,6‐diethylanine) (MDEA), and the resulting blends characterized by the use of dynamic thermal mechanical analysis (DMTA), rheometry, and fracture mechanics tests. The morphology of the blends was studied by the use of scanning electron microscopy (SEM). The different molecular weights of the copolymers had a significant effect on the rheological and thermomechanical properties of the resins, as well as the different end groups on the reaction rate and on the thermomechanical properties of the blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 250–257, 2006
Melt index prediction by weighted least squares support vector machines
Authors: Shi Jian , Liu Xinggao
Published: April 2006

Melt index is considered an important quality variable determining product specifications. Reliable prediction of melt index (MI) is crucial in quality control of practical propylene polymerization processes. In this paper a least squares support vector machines (LS‐SVM) soft‐sensor model of propylene polymerization process is developed to infer the MI of polypropylene from other process variables. Considering the use of a SSE cost function without regularization might lead to less robust estimates; the weighted least squares support vector machines (weighted LS‐SVM) approach of propylene polymerization process is further proposed to obtain a robust estimation of melt index. The performance of standard SVM model is taken as a basis of comparison. A detailed comparison research among the standard SVM, LS‐SVM, and weighted LS‐SVM models is carried out. The research results confirm the effectiveness of the presented methods. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 285–289, 2006
Waterborne polyurethanes: Spectroscopy and stability of emulsions
Authors: Zhang Subiao , Lv Hongtao , Zhang Han , Wang Bing , Xu Yingmei
Published: April 2006

We prepared waterborne polyurethanes based on isophorone diisocyanate, dimethylolpropionic acid, polyhexane neopentyl adipate glycol, or polyethylene–butylene adipate glycol through self‐emulsion (a prepolymerization process). Their IR and NMR spectroscopic properties were investigated, and the peaks of these spectra were assigned. The stability of the emulsions was studied on the basis of the shelf life and particle size distribution of emulsions. The effects of solvents, hard‐segment content, carboxylic group content, extenders, and feeding methods on the stability of the emulsions were determined to show that N‐methylpyrrolidone was a good solvent for retaining the stability of emulsions; particle sizes decreased with increasing COOH content and decreasing hard‐segment content, whereas the extenders and feeding methods studied had little effect on the stability of the emulsions. The causes of the stability of the emulsions are discussed according to the analysis of the molecular and particulate structures. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 597–602, 2006
Synthesis and characterization of the environmental‐sensitive hyperbranched polymers as novel carriers for controlled drug release
Authors: Hu Hui , Fan Xiao‐Dong , Cao Zhong‐Lin , Cheng Wei‐Xing , Liu Yu‐Yang
Published: April 2006

Novel hyperbranched polymers, which contain a hydrophobic branched poly(p‐(chloromethy)styrene) (PCMS) core and poly(N,N‐dimethylaminoethyl methacrylate) (PDMA) shell that exhibited environmental sensitivity, have been synthesized by atom transfer radical polymerization (ATRP). At first, a hyperbranched polymer (PCMS) core is obtained via ATRP of p‐(chloromethy)styrene (CMS), which may act as an “inimer”‐monomer and initiator. Then the modified hyperbranched polymers having different average arm length consisting of PCMS and PDMA are synthesized by ATRP using anterior PCMS as macroinitiators. Their macromolecular structures are characterized by FTIR and 1H NMR. Using chlorambucil as a model drug, the behaviors of the controlled drug release from the environmental‐sensitive hyperbranched polymers with different average chain length of PDMA and degree of branching are studied. The data demonstrate that the rate of the drug release can be effectively controlled by pH value, and these environmental‐sensitive hyperbranched polymers have the potential to be used as novel carriers in some controlled drug release systems in the future. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 311–316, 2006
Bismaleimide monomers with amide units: Synthesis and properties
Authors: Sava M.
Published: April 2006

A series of bismaleimide monomers with amide groups were prepared and characterized. Structurally different bismaleimides (with amide units) were synthesized by a reaction between 4‐maleimidobenzoyl chloride and various diamines. The monomers were characterized by infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and elemental analysis. The thermal characterization of the bismaleimides was accomplished with differential scanning calorimetry and dynamic thermogravimetric analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 567–572, 2006
Preparation of hyperbranched polymers through ATRP of in situ formed AB* monomer
Authors: Gong Fanghond , Tang Honglan , Liu Chunlin , Jiang Bibiao , Ren Qiang , Yang Yang
Published: April 2006

The self‐condensing vinyl polymerization of an AB* monomer formed in situ by atom transfer radical addition from divinylbenzene (DVB) and (1‐bromoethyl)benzene (BEB) using atom transfer radical polymerization technique was studied. The catalyst concentration has a dramatic effect on polymerization. To study the polymerization mechanism and to achieve high molecular weight polymer, the polymerization was carried out in bulk with a catalyst to monomer ratio, 2,2′‐bipyridine to DVB, of 0.2 at 90°C. Proton nuclear magnetic resonance (1H NMR) spectroscopy and size‐exclusion chromatography coupled with multiangle laser light scattering were used to analyze the polymerization aliquots and the obtained polymer. The intrinsic viscosities of the prepared polymers were also measured. Experimental results, from the comparison of the apparent molecular weights measured by size‐exclusion chromatography with the absolute values measured by multiangle laser light scattering as well as viscosity measurements, indicate the existence of hyperbranched structures in the prepared polymers. In sharp contrast to hyperbranched polymers from AB* monomer preprepared, hyperbranched ploy(divinylbenzene) prepared at equimolar amount of DVB and BEB has numerous residual pendant vinyl groups rather than only one double bond at its focal point. The hyperbranched polymers show relatively narrow molecular weight distribution (2.13–3.77) and exhibit excellent solubility in common organic solvents such as acetone. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 850–856, 2006
BIMS/filler interactions. II. Effects of filler concentration and BIMS structure
Authors: Tse M. F.
Published: April 2006

Brominated isobutylene para‐methylstyrene (BIMS) elastomer is a terpolymer of isobutylene, para‐methylstyrene (PMS), and para‐bromomethylstyrene (BrPMS). Viscoelastic measurements have been used to characterize the blends of this BIMS elastomer with different concentrations of a carbon black (CB) filler, N234. Data in the low temperature/high frequency region suggest that N234 at a concentration less than or equal to 15 vol % in BIMS appears not to affect the Tg of BIMS although a slight increase in relaxation time in the transition zone is observed. Also, the effects of BrPMS and PMS contents in BIMS on BIMS/N234 CB interactions have been qualitatively investigated by using the bound rubber measurements. To assess BIMS/CB interactions with reference to diene rubber/CB interactions, mixing of BIMS with various amounts of a polybutadiene rubber in the presence of CB has been performed. Atomic force microscopy and image processing have been employed to quantify filler phase distributions in these blends for a practical ranking of polymer/CB interactions. Preferential partition of CB in the BIMS or BR phase depends on the BrPMS content in BIMS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 659–667, 2006
Graft copolymerization of methacrylonitrile on caesarweed fibers by ceric ion/isopropanol redox pair
Authors: Eromosele C. O. , Oloye M. , Eromosele I. C.
Published: April 2006

The graft copolymerization of methacrylonitrile to caesarweed fiber and its sodium derivative by ceric ions in the presence of isopropanol was investigated in aqueous media. The percentage graft yield decreased initially and then increased with the concentration of isopropanol, but the graft levels of sodium caesarweed fibers were much lower. The graft reaction in the presence of isopropanol was characterized by the high frequency of grafting, up to 2.81 × 102 Ng/104 anhydroglucose units, and the low molecular weight of the grafted polymer, not higher than 0.94 × 103. The molecular weight of the grafted polymer showed a negative dependence on the concentration of isopropanol, suggesting the involvement of the latter in the transfer reactions with growing grafted polymer chains, which permitted calculation of the transfer constant, kA/kp, for the process: 7.91 × 10−2. The graft yield percent was found to be negatively dependent on the concentration of ceric ions for grafting of methacrylonitrile on sodium caesarweed fibers, but the molecular weight of the grafted polymer showed no clear‐cut trend with ceric ion concentration. The graft yield percent increased with temperature in the range of 30°C–50°C and decreased markedly at 70°C. The calculated activation energy of the graft reaction was 10.5 kcal/mol. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 353–358, 2006
Synthesis and properties of polystyrene‐b‐poly(ethylene oxide)‐b‐polystyrene triblock copolymers
Authors: Xu Dong‐Mei , Zhang Ke‐Da , Wu Jian‐Feng
Published: April 2006

A series of well‐defined and property‐controlled polystyrene (PS)‐b‐poly(ethylene oxide) (PEO)‐b‐polystyrene (PS) triblock copolymers were synthesized by atom‐transfer radical polymerization, using 2‐bromo‐propionate‐end‐group PEO 2000 as macroinitiatators. The structure of triblock copolymers was confirmed by1H‐NMR and GPC. The relationship between some properties and molecular weight of copolymers was studied. It was found that glass‐transition temperature (Tg) of copolymers gradually rose and crystallinity of copolymers regularly dropped when molecular weight of copolymers increased. The copolymers showed to be amphiphilic. Stable emulsions could form in water layer of copolymer–toluene–water system and the emulsifying abilities of copolymers slightly decreased when molecular weight of copolymers increased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 727–730, 2006
Effect of screw rotation speed on the properties of polystyrene/organoclay nanocomposites prepared by a twin‐screw extruder
Authors: Tanoue Shuichi , Hasook Aniwat , Itoh Takumi , Yanou Masaharu , Iemoto Yoshiyuki , Unryu Tsunemune
Published: April 2006

We discuss the effect of screw rotation speed on the mechanical and rheological properties and clay dispersion state of polystyrene (PS)/organoclay (clay) nanocomposites prepared by melt compounding with a counterrotating‐type twin‐screw extruder. Poly(styrene‐co‐vinyloxazolin) (OPS) was used as an additional material. The Young's modulus of the PS/OPS/clay nanocomposites showed the maximum value at a screw rotation speed of 70 rpm in this study. This implied the existence of an optimized screw rotation speed for the melt compounding of the polymer/clay nanocomposites. For PS/clay systems without the addition of OPS, the peak intensity from clay increased and the distance between clay platelets in the nanocomposites decreased with the screw rotation speed. On the other hand, inverse results were obtained for PS/OPS/clay systems. According to the transmission electron microscopy photographs, the PS/OPS/clay nanocomposite at 70 and 100 rpm had fully exfoliated clay platelets. The dynamic rheological properties of the PS/clay nanocomposites were almost the same as those of neat PS. On the other hand, the storage and loss moduli of the PS/OPS/clay nanocomposites at the same frequency were larger than those of the PS/clay system. On the whole, the bonding between clay platelets and PS was important for increasing the viscosity and elasticity in the melts of the PS/clay system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1165–1173, 2006
Superabsorbent hydrogel of acrylic acid/potassium acrylate copolymers by ultraviolet photopolymerization: Synthesis and properties
Authors: Weiqing Ruan , Xiaogong Wang , Yanqing Lian , Yuli Huang , Aijie Niu
Published: April 2006

Synthesis of superabsorbent hydrogel (SAHG) of acrylic acid‐potassium acrylate copolymer by direct Ultraviolet (UV) photopolymerization is a new method. The effects of degree of neutralization of acrylic acid (AA), photoinitiators, crosslinking agents, and exposure time of UV light on water absorbent properties were investigated. The results showed that the water absorbency (Q) and the salt solution (NaCl, 0.9%) absorbency (Qs) of SAHG, based on Irgacure 651, are high, reaching about 1400 and 130 mL/g, respectively. UV absorption spectrum proved that peak of UV absorption of Irgacure 651 matched the UV light source we used. Among the crosslinking agents, N,N′‐methylene bisacrylamide is more efficient than others, because of its very small content and high Q. 13C NMR spectrometry was used to identify the mechanism of crosslinking reaction through esterification of hydroxyethyl acrylate (HEA) and 2‐hydroxypropyl acrylate (HPA) with carboxylic acid group in acrylic acid‐ammonium acrylate copolymerization, but efficiency of crosslinking reaction by esterification was lower than that of copolymerization of vinyl group in crosslinking agent. The Q of acrylic acid‐potassium acrylate copolymer of SAHG reaches 1592 mL/g under the following conditions: degree of neutralization of acrylic acid is 80%, content of Irgacure 651 is 0.25 wt %, content of HEA is 0.2 wt %, and exposure time is 10 min. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1181–1187, 2006
Gauge length effect on the tensile properties of leather
Authors: Thanikaivelan Palanisamy , Shelly Dennis C. , Ramkumar Seshadri S.
Published: April 2006

Tensile properties are important basic characteristics of materials and influence their end‐use and performance. More importantly, in the case of leather due to end‐use applications such as shoe uppers, automotive and furniture upholstery, mechanical properties such as tenacity are of extreme importance. Therefore, fundamental studies on the tensile properties of leather are needed. In this study, an attempt has been made to examine the effect of gauge length (GL) on the tensile properties of shoe upper leather. Two different specimens in the form of rectangular and dumbbell shapes have been cut from parallel and perpendicular directions to the body axis of the leather and have been tested. Results showed that the maximum breaking load and the percentage extension at break decreased with the increase in GL. Rectangular specimens showed a 30% decrease in maximum breaking load and a 13% decrease in percentage extension at break, while dumbbell specimens showed reductions in the order of 28 and 6%, respectively, as the GL increased from 9.53 cm to 23.5 cm. Highly varying supramolecular architecture of the collagen matrix and the frictional slippage caused by the free ends present in the collagen fibrils, which induce a weak‐link effect similar to the one found in cotton fibers and yarns, are considered to be the probable reasons for this behavior. A limited scanning electron microscopic study has been undertaken to pictorially represent the breakage of leather at different GLs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1202–1209, 2006
Effect of baking treatment and materials composition on the properties of bulky PMMA–silica hybrid sol–gel materials with low volume shrinkage
Authors: Yeh Jui‐Ming , Weng Chang‐Jian , Huang Kuan‐Yeh , Lin Chun‐Che
Published: April 2006

A series of bulky PMMA–silica hybrid sol–gel materials had been successfully prepared through the conventional HCl‐catalyzed sol–gel approach with 2‐hydroxyethyl methyl methacrylate (HEMA) as coupling agent under pumping pretreatment (i.e., exhaustive vacuum evacuation). In this work, the hydroxyl groups of HEMA monomers were first cohydrolyzed with various contents of tetraethyl orthosilicate (TEOS) to afford chemical bonding for the forming silica networks by removal of solvent and byproduct of sol–gel reactions through pumping pretreatment before gelation reactions. Subsequently, the resultant viscous solution was then copolymerized with methyl methacrylate (MMA) monomers at specific feeding ratios by using benzoyl peroxide (BPO) as free‐radical initiator. Eventually, transparent bulky organic–inorganic hybrid sol–gel materials loaded with different silica content were always achieved. The obtained bulky hybrid sol–gel materials were found to be transparent, crack‐free, and of relatively low volume shrinkages even in high silica content. The as‐prepared bulky hybrid sol–gel materials were then characterized through silicon element mapping studies of energy‐dispersive X‐ray (EDX) and transmission electron microscopy (TEM). Effect of heating process at 150°C for 5 h after polymerization and material composition on the thermal properties, mechanical strength, and optical clarity of a series of bulky PMMA–silica hybrid sol–gel materials was investigated and compared by thermogravimetric analysis (TGA), thermomechanical analysis (TMA), hardness test, dynamic mechanical analysis (DMA), and UV–vis transmission spectroscopy, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1151–1159, 2006
Synthesis of Sulfated Galactocerebrosides from an Orthogonal β‐D‐Galactosylceramide Scaffold for the Study of CD1–Antigen Interactions
Authors: Compostella Federica , Ronchi Silvia , Panza Luigi , Mariotti Sabrina , Mori Lucia , De Libero Gennaro , Ronchetti Fiamma
Published: April 2006

CD1a protein binds sulfatide (3‐O‐sulfo‐β‐D‐galactosylceramide) to form an antigen complex that interacts with T cell receptors and activates T cells. To assess the role of the position of the sulfate in T cell activation, the synthesis of three β‐D‐galactosylceramides, variously bearing a sulfate at position 2, 4, or 6 of galactose, has been planned and carried out. The compounds were synthesized by an orthogonal sulfation strategy from a common β‐D‐galactosylceramide scaffold, which was in turn obtained through an efficient glycosylation reaction between a fully orthogonally protected galactosyl imidate and 3‐O‐benzoylazidosphingosine. Immunological evaluation of the three sulfated compounds in CD1a‐mediated T cell activation, in comparison with natural sulfatide, provided evidence of the influence of the sulfate position in the recognition event between the antigen, the CD1 protein and the T cell receptor.
Deconvoluting the Memory Effect in Pd‐Catalyzed Allylic Alkylation: Effect of Leaving Group and Added Chloride
Authors: Fristrup Peter , Jensen Thomas , Hoppe Jakob , Norrby Per‐Ola
Published: April 2006

An analysis of product distributions in the Tsuji–Trost reaction indicates that several instances of reported “memory effects” can be attributed to slow interconversion of the initially formed syn‐ and anti‐[Pd(η3‐allyl)] complexes. Addition of chloride triggers a true memory effect, in which the allylic terminus originally bearing the leaving group has a higher reactivity. The latter effect, termed regioretention, can be rationalized by ionization from a palladium complex bearing a chloride ion, forming an unsymmetrically substituted [Pd(η3‐allyl)] complex. DFT calculations verify that the position trans to the phosphine ligand is more reactive both in the initial ionization and in the subsequent nucleophilic attack.
Crystal Structure of ErAlGeO5 and Evidence of a Peculiar Double Coordination Sphere of Al(III) and Ge(IV) Cations.
Authors: Durand Alexandre , Mentre Olivier , Abraham Francis , Fukuda Tsuguo , Elouadi Brahim
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Density‐Functional Calculation of the 183W and 17O NMR Chemical Shifts for Large Polyoxotungstates
Authors: Gracia Jose , Poblet Josep M. , Autschbach Jochen , Kazansky Leonid P.
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Reactions of 4‐Pentenoic Acid with Sulfenyl Cations Generated Electrochemically from Bisquinolinyl and Bispyridinyl Disulfides.
Authors: Marciniec Krzysztof , Maslankiewicz Andrzej , Maslankiewicz Maria J. , Ciunik Zbigniew
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Microwave‐Assisted Efficient Synthesis of Diimines in Dry Media Using Silica Gel Supported Sodium Hydrogen Sulfate as Reusable Solid Support.
Authors: Bazgir Ayoob
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Sulfoxide‐Modified Julia—Lythgoe Olefination: Highly Stereoselective Di‐, Tri‐, and Tetrasubstituted Double Bond Formation.
Authors: Pospisil Jiri , Pospisil Tomas , Marko Istvan E.
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
2‐(1,3‐Dioxan‐2‐yl)ethylsulfonyl Group: A New Versatile Protecting and Activating Group for Amine Synthesis.
Authors: Sakamoto Izumi , Izumi Norimasa , Yamada Taeko , Tsunoda Tetsuto
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Nickel‐Catalyzed Coupling of Allyl Chlorides and Enynes.
Authors: Ikeda Shin‐ichi , Suzuki Kaori , Odashima Kazunori
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Ambidentate Properties of Asymmetric Substituted Imidazoles. Direction of Benzylation of 2‐[N‐(4‐Chlorophenyl)carbamoyl]methylthio‐4‐phenyl‐1H‐imidazole.
Authors: Ivanova A. G. , Kombarov R. V. , Davidenko P. V. , Rodin O. G.
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis and Structure Elucidation of 1‐Aryl‐Substituted Tetrahydropyridone Derivatives.
Authors: Mickevicius V. , Vaickelioniene R. , Mikulskiene G. , Sewald N.
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
One‐Pot Synthesis of 10‐Methyl‐1,2,3,4,5,6,7,8,9,10‐decahydroacridine‐1,8‐dione Derivatives under Microwave Heating Without Catalyst.
Authors: Hua Guo‐Ping , Zhang Xiao‐Jing , Shi Feng , Tu Shu‐Jiang , Xu Jia‐Ning , Wang Qian , Zhu Xiao‐Tong , Zhang Jin‐Peng , Jl Shun‐Jun
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
1‐(3‐Chloropropyl)‐3‐phenylbenzothieno[2,3‐c]pyridine (II): An Intermediate in Synthesis of 5‐Phenylbenzothieno[2,3‐e]indolizinium Salts (III).
Authors: Kryuchkov M. A. , Tolkunov S. V.
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Novel Endoperoxides: Synthesis and Activity Against Candida Species.
Authors: Macreadie Peter , Avery Thomas , Greatrex Ben , Taylor Dennis , Macreadie Ian
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Facile and Efficient Asymmetric Synthesis of α‐Aminoalkylphosphonic Acids
Authors: Yuan Cheng‐Ye , Chen Qian‐Yi
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Diastereoselective Synthesis of All Eight L‐Hexoses from L‐Ascorbic Acid.
Authors: Ermolenko Ludmila , Sasaki N. Andre
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Total Synthesis of Strobilurin B Using a Hetero‐bis‐Metalated Pentadiene Linchpin.
Authors: Coleman Robert S. , Lu Xiaoling
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Conversion of Potent MMP Inhibitors into Selective TACE Inhibitors.
Authors: Cherney Robert J. , King Bryan W. , Gilmore John L. , Liu Rui‐Qin , Covington Maryanne B. , Duan James J.‐W. , Decicco Carl P.
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Reactions of Neutral Transition Metal Atoms with Small Molecules in the Gas Phase
Authors: Schroden Jonathan J. , Davis H. Floyd
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
A Synthon Approach to Spiro Compounds
Authors: Pradhan Rosy , Patra Manabendra , Behera Ajaya K. , Mishra Bijay K. , Behera Rajani K.
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
A Novel Approach to the Efficient Oxygenation of Hydrocarbons under Mild Conditions. Superior Oxo Transfer Selectivity Using Dioxiranes
Authors: Curci Ruggero , D'Accolti Lucia , Fusco Caterina
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Electrophoretic NMR Studies of Polymer and Surfactant Systems
Authors: Griffiths P. C. , Paul A. , Hirst N.
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
From Structure to Chemical Shift and vice‐versa
Authors: Hunter Christopher A. , Packer Martin J. , Zonta Cristiano
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Dietary selenium intake, aldehyde dehydrogenase‐2 and X‐ray repair cross‐complementing 1 genetic polymorphisms, and the risk of esophageal squamous cell carcinoma
Authors: Cai Lin , You Nai‐Chieh Yuko , Lu Hua , Mu Li‐Na , Lu Qing‐Yi , Yu Shun‐Zhang , Le Anh D. , Marshall James , Heber David , Zhang Zuo‐Feng
Published: April 2006

BACKGROUND

To the authors' knowledge, few studies have been conducted to date regarding dietary selenium and the potential gene‐nutrient interactions with single‐nucleotide polymorphisms (SNPs) in different pathways on the risk of esophageal cancer.

METHODS

The authors investigated the role of dietary selenium intake and its interplay with SNPs of the ALDH2 (glutamic acid [Glu] 487 lysine [Lys]) and the X‐ray repair cross‐complementing 1 (XRCC1) (arginine [Arg] 399 glutamine [Gln]) genes on the risk of esophageal squamous cell carcinoma (ESCC) in a population‐based, case‐control study in China. In total, 218 patients with ESCC and 415 healthy population control participants were interviewed. Dietary selenium intake was estimated from a food frequency questionnaire with 97 food items. ALDH2 and XRCC1 polymorphisms were detected with a polymerase chain reaction‐restriction fragment length polymorphism assay.

RESULTS

The adjusted odds ratio (OR) for the highest quintile of dietary selenium intake, compared with the lowest quintile of intake, was 0.48 (95% confidence interval [95% CI], 0.25‐0.89), with a strong dose‐response relation (P for trend, <.01). The ALDH2 Lys and XRCC1 Gln variant alleles were associated with an increased risk of ESCC with adjusted ORs of 1.91 (95% CI, 0.96‐3.80) and 1.67 (95% CI, 1.08‐2.59), respectively. An elevation of the risk for ESCC was pronounced most among carriers of ALDH2 Lys/Lys and XRCC1 399Gln/Gln or Gln/Arg who consumed a low level of dietary selenium (adjusted OR, 4.16; 95% CI, 1.14‐15.12).

CONCLUSIONS

To the authors' knowledge, this is the first in‐depth study to suggest that genetic susceptibility may modify the association between selenium intake and the risk of ESCC. The findings indicated that individuals with low dietary selenium intake and ALDH2 Lys/Lys and XRCC1 399Gln/Gln or Gln/Arg genotypes were associated with an increased ESCC risk, especially in the presence of exposure to tobacco and alcohol carcinogens. Cancer 2006. © 2006 American Cancer Society.
A Two‐Step Spin Transition and Order–Disorder Phenomena in the Mononuclear Compound [Fe(Hpy‐DAPP)](BF4)2
Authors: Matouzenko Galina S. , Luneau Dominique , Molnár Gábor , Ould‐Moussa Nawell , Zein Samir , Borshch Serguei A. , Bousseksou Azzedine , Averseng Frédéric
Published: April 2006

This paper reports the synthesis and detailed characterization of the mononuclear complex [FeII(Hpy‐DAPP)](BF4)2 (Hpy‐DAPP = {bis[N‐(2‐pyridylmethyl)‐3‐aminopropyl](2‐pyridylmethyl)amine}), which manifests a two‐step spin crossover accompanied by an ordering and a conformational transition in the ligand. The magnetic susceptibility measurements and Mössbauer spectra reveal that the two steps of the spin transition are separated by an inflexion point at about 130 K at which 50 % of the complex undergoes a spin conversion. The high‐temperature step centered at 181 K is gradual, whereas the low‐temperature one displays a thermal hysteresis with two transition temperatures (Tc↓ = 119 and Tc↑ = 123 K). The single‐crystal X‐ray structure has been determined for the HS (298 K) and LS (90 K) forms, as well as for the mixed form with an HS:LS ratio of 1:1 (130 K). The structural studies show that the crystal lattice contains a single FeII crystallographic site over the whole temperature range. At room temperature, the most important peculiarity of the HS complex structure is the disorder of the N3 amino aliphatic atom, which is in the first coordination sphere of FeII, over two positions. The strong involvement of the N3 atoms in H‐bonding with two neighboring counterions is considered as a possible origin of this disorder. At 130 K, the disorder is increased by the distribution of the N1 and C9 atoms over two positions, leading to the conformational disorder (chair and twist‐boat conformations with a 1:1 ratio) in the six‐membered N2C7C8C9N1Fe chelate cycle. At 90 K, the disorder in the positions of the N1, N3, and C9 atoms disappears and the N2C7C8C9N1Fe metallacycle adopts a unique twist‐boat conformation. The results of structural studies suggest that the two‐step spin‐transition behavior of the complex [Fe(Hpy‐DAPP)](BF4)2 is induced by two different geometries of the [FeN6] coordination core generated by the disorder in the ligand. The HS → LS transition is also associated with the conformational change in the chelate cycle. Both crystallographic data analysis and electronic structure calculations allow us to relate the disordered geometries of the [FeN6] coordination core to their HS and LS character. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Structure and Function of Xanthine Oxidoreductase
Authors: Hille Russ
Published: April 2006

An overview of the current state of our understanding of the reaction mechanism of the molybdenum‐containing enzyme xanthine oxidoreductase is presented, with an emphasis on work done in the past five years. Recent studies of the biosynthesis of the pterin cofactor bound to the metal in the active site are also reviewed, as is crystallographic work that has clarified the coordination geometry of the molybdenum center. This structural work provides the context in which to understand recent mechanistic studies of the enzyme, in particular those aimed at elucidating the role of specific amino acid residues in the active site of the enzyme.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Contemporary sedimentation rates and depositional structures in a montane lake basin, southern Coast Mountains, British Columbia, Canada
Authors: Schiefer Erik
Published: April 2006

Spatial variability of recent lacustrine sedimentary structures and sedimentation rates are examined for Green Lake, a morphologically complex lake basin of the southern Coast Mountains, British Columbia. A dense, 100 m grid sampling scheme was used for sediment coring within the 2 km2 lake basin. Deltaic, massive, weakly laminated, and varved sediment sequences are identified within the sediment record. Spatial patterns among these sedimentary deposits are related to within‐lake sediment transfer processes, morphometric controls, and the extent of post‐depositional mixing by bioturbation. Unconformities, turbidites, and cohesive slump failure deposits, observed within the contemporary varve sequences, could all be correlated with major flooding events in the catchment area and direct anthropogenic disturbances along the shoreline. There is an overall, non‐linear decrease in sedimentation rates with increasing distance from the lake inflows; however, this pattern is disrupted in deep water sites of intervening lake sub‐basins where locally higher accumulation rates are observed. Spatial sedimentation patterns are quantitatively described by an empirically‐derived model. Systematic variations in the model parameters are observed for different lake sub‐regions and are associated with changing sediment transfer dynamics between proximal and distal sub‐basin settings. Copyright © 2006 John Wiley & Sons, Ltd.
Enhancing the quality of teaching and learning: The U.S. experience
Authors: Rice R. Eugene
Published: April 2006

In the United States greater attention is being paid to learning that is more collaborative, actively engaged, and technologically enhanced.
University teaching in South Africa: An African philosophical perspective
Authors: Higgs Philip , van Wyk Berte
Published: April 2006

A new philosophical perspective is suggested that would transform and Africanize curricula, teaching, and learning in South African universities.
Changes in Brazilian higher education and their effects on the enhancement of teaching (1995–2005)
Authors: Sobrinho José Dias
Published: April 2006

Two evaluation models were used in Brazil as tools for policies of higher education undertaken by two different administrations.
Comparing approaches taken in different countries
Authors: Kreber Carolin
Published: April 2006

The level of funding made available for pedagogical innovation, a function of external policy context, is important but not sufficient for effecting lasting change in higher education teaching.
Predicting protein subcellular location by fusing multiple classifiers
Authors: Chou Kuo‐Chen , Shen Hong‐Bin
Published: April 2006

One of the fundamental goals in cell biology and proteomics is to identify the functions of proteins in the context of compartments that organize them in the cellular environment. Knowledge of subcellular locations of proteins can provide key hints for revealing their functions and understanding how they interact with each other in cellular networking. Unfortunately, it is both time‐consuming and expensive to determine the localization of an uncharacterized protein in a living cell purely based on experiments. With the avalanche of newly found protein sequences emerging in the post genomic era, we are facing a critical challenge, that is, how to develop an automated method to fast and reliably identify their subcellular locations so as to be able to timely use them for basic research and drug discovery. In view of this, an ensemble classifier was developed by the approach of fusing many basic individual classifiers through a voting system. Each of these basic classifiers was trained in a different dimension of the amphiphilic pseudo amino acid composition (Chou [2005] Bioinformatics 21: 10–19). As a demonstration, predictions were performed with the fusion classifier for proteins among the following 14 localizations: (1) cell wall, (2) centriole, (3) chloroplast, (4) cytoplasm, (5) cytoskeleton, (6) endoplasmic reticulum, (7) extracellular, (8) Golgi apparatus, (9) lysosome, (10) mitochondria, (11) nucleus, (12) peroxisome, (13) plasma membrane, and (14) vacuole. The overall success rates thus obtained via the resubstitution test, jackknife test, and independent dataset test were all significantly higher than those by the existing classifiers. It is anticipated that the novel ensemble classifier may also become a very useful vehicle in classifying other attributes of proteins according to their sequences, such as membrane protein type, enzyme family/sub‐family, G‐protein coupled receptor (GPCR) type, and structural class, among many others. The fusion ensemble classifier will be available at www.pami.sjtu.edu.cn/people/hbshen. J. Cell. Biochem. 99: 517–527, 2006. © 2006 Wiley‐Liss, Inc.