bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of grafted polymer architecture and fluid hydrodynamics on protein separation by entropic interaction chromatography
Authors: Coad Bryan R. , Steels Bradley M. , Kizhakkedathu Jayachandran N. , Brooks Donald E. , Haynes Charles A.
Published: December 2006

Entropic interaction chromatography (EIC) provides efficient size‐based separation of protein mixtures through the entropy change associated with solute partitioning into a layer of hydrophilic homopolymer that has been end‐grafted within the pores of a macroporous chromatography support. In this work, surface‐initiated atom‐transfer radical polymerization (ATRP) is used to prepare a library of EIC stationary phases covering a wide range of grafted‐chain densities and molecular weights. Exhaustive chain cleavage and analysis by saponification and GPC‐MALLS, respectively, show that the new ATRP synthesis procedure allows for excellent control over graft molecular weight and polydispersity. The method is used to prepare high‐density grafts (up to 0.164 ± 0.005 chains/nm2) that extend the range of EIC applications to include efficient buffer‐exchange and desalting of protein preparations. Reducing the graft density allows for greater partitioning of high molecular weight solutes, extending the linear range of the selectivity curve. Increasing graft molecular weight also alters selectivity, but more directly affects column capacity by increasing the volume of the grafted layer. Protein partitioning in high‐density EIC columns is found to decrease with mobile‐phase velocity (u). Although solute mass transfer resistances leading to an increase in plate height can explain this effect, pressure drop data across the column are indicative of weak convective flow through at least a fraction of the grafted architecture. Modeling of the grafted brush properties in the presence of solvent flow by subjecting a self‐consistent‐field theory representation of the brush to a viscous shear force predicts that the grafted chains will tilt and elongate in the direction of flow. The shear force may therefore act to reduce the number of conformations available to chains, increasing their rigidity without significantly altering the thickness of the grafted layer. A reduction in protein partitioning is then predicted when the dependence on u of the solute entropy loss is stronger than that of the grafted polymer, a condition met at high graft densities. Biotechnol. Bioeng. 2007;97: 574–587. © 2006 Wiley Periodicals, Inc.
Fatal ischemic stroke related to nonpermissive peripheral artery access for percutaneous aortic valve replacement
Authors: Berry Colin , Cartier Raymond , Bonan Raoul
Published: December 2006

This report describes an 85 year‐old man who underwent percutaneous aortic valve replacement (PAVR). With a logistic euroSCORE of 37%, the patient had been refused surgical aortic valve replacement because of an unacceptably high peri‐operative risk. During the PAVR procedure, severe resistance was encountered when advancing the 21 Fr delivery catheter through the left iliac artery despite pre‐dilatation with a 7 mm balloon. Following this, PAVR was promptly achieved without difficulty, with excellent valve positioning, no peri‐valvular leak and good hemodynamics. However, transesophageal echocardiography revealed a mobile echogenic mass within the outflow tract of the left ventricle. The mass was retrieved with a cardiac bioptome manipulated via the left femoral artery through a 9 Fr sheath. A right cerebral ischemic stroke manifested shortly after the post‐procedure and the patient died on the fourth post‐operative day. Post‐mortem findings revealed a left subclavian artery occlusion by iliac vascular tissue. This report highlights the imperative for device‐specific vascular access screening criteria and the need to minimize device size in order to safely accomplish PAVR. © 2006 Wiley‐Liss, Inc.
Dry film method with ytterbium as the internal standard for near infrared spectroscopic plasma glucose assay coupled with boosting support vector regression
Authors: Zhou Yan‐Ping , Jiang Jian‐Hui , Wu Hai‐Long , Shen Guo‐Li , Yu Ru‐Qin , Ozaki Yukihiro
Published: December 2006

A novel near infrared (NIR) spectroscopic measurement technique, dry film method, has been proposed for the determination of glucose in plasma. Rare earth element ytterbium (Yb) has been taken in the dry film method as the internal standard to compensate for the thickness variation of the dry films. This technique circumvents the interference from water absorption and requires only 50 µl of sample. Support vector regression (SVR) as a multivariate calibration method has been combined with boosting for the development of a boosting support vector regression (BSVR) method for the dry film measurement modeling. The introduction of boosting drastically enhances the performance of individual SVR model. The results show that the glucose in plasma can be determined over the 0.4–20 mmol/L concentration range with satisfactory accuracy using the dry film technique coupled with the BSVR method. Moreover, the performance of BSVR was compared favorably with that of the conventional SVR and PLS. Copyright © 2006 John Wiley & Sons, Ltd.
Reengineering for Parallelism: an entry point into PLPP for legacy applications
Authors: Massingill Berna L. , Mattson Timothy G. , Sanders Beverly A.
Published: December 2006

Many parallel programs begin as legacy sequential code that is later reengineered to take advantage of parallel hardware. This paper presents a pattern called Reengineering for Parallelism to help with this task. The new pattern is intended to be used in conjunction with PLPP (Pattern Language for Parallel Programming), described in our book (Mattson TG, Sanders BA, Massingill BL. Patterns for Parallel Programming. Addison‐Wesley: Reading, MA, 2004). PLPP contains a structured collection of patterns and embodies a methodology for developing parallel programs in which the programmer starts with a good understanding of the problem, works through a sequence of patterns, and finally ends up with the code. Most of the patterns in PLPP are also applicable when reengineering legacy code, but it is not always clear how to get started. Reengineering for Parallelism provides an alternate point of entry into PLPP and addresses particular issues that arise when dealing with legacy code. Copyright © 2006 John Wiley & Sons, Ltd.
Stabilizing large‐scale generalized systems on parallel computers using multithreading and message‐passing
Authors: Benner Peter , Castillo Maribel , Mayo Rafael , Quintana‐Ortí Enrique S. , Quintana‐Ortí Gregorio
Published: December 2006

We discuss the parallelization of an efficient algorithm for the partial stabilization of large‐scale linear control systems in generalized state‐space form. The algorithm is composed of highly parallel iterative schemes that appear in the computation of certain matrix functions. Here we evaluate different approaches to exploit parallelism at two levels, based on threads and processes. Our experimental results on a cluster of symmetric multiprocessors and a CC‐NUMA platform show that the efficiency of the matrix operations underlying the iterative schemes carry over to the parallel implementation of the stabilization algorithm. Copyright © 2006 John Wiley & Sons, Ltd.
The Properties of Si1–xGex Nanodot Arrays Prepared by Plasma‐Enhanced CVD on Porous Alumina Templates
Authors: Hu H. , He D.
Published: December 2006

Si1–xGex films with nanodot arrays are prepared on anodic aluminum oxide (AAO) templates by plasma‐enhanced (PE)CVD. The structure and morphology of the films are investigated using X‐ray diffraction (XRD) spectroscopy and transmission electron microscopy (TEM). It is found that the size of the Si1–xGex grains is controlled by the pore diameter of the alumina substrate, which can be modulated during the preparation process. Intense visible photoluminescence (PL) is observed from the samples, and a remarkable red‐shift of the luminescence peak position is shown with increase in the content of Ge. Conductivity measurements show that electron tunneling is enhanced with increase of the strains stored in the sample.
Effects of Synthesis Conditions on Self‐Organized Growth of Aligned Arrays of Silicon Nanowires
Authors: Niu J.‐J. , Wang J.‐N.
Published: December 2006

The effects of CVD synthesis conditions, including nanochannel alumina (NCA) properties, catalyst distribution, and growth parameters on aligned arrays of silicon nanowires (SiNWs) are investigated. Array‐ordered SiNWs are achieved by optimizing the above factors according to the vapor–liquid–solid (VLS) and nanochannel physical limitation mechanism. The study of arrays of SiNWs will permit better understanding of the growth mechanism and develop potential applications in nanoelectronics technology.
Plasma Characterization of Oxygen‐Tetramethylsilane Mixtures for the Plasma‐Enhanced CVD of SiOxCyHz Thin Films
Authors: Yanguas‐Gil Á. , Barranco Á. , Cotrino J. , Gröning P. , González‐Elipe A. R.
Published: December 2006

The plasma‐enhanced (PE)CVD of SiOxCyHz thin films from O2/Ar/tetramethylsilane (TMS) mixtures, in a low‐pressure microwave electron cyclotron resonant (ECR) plasma reactor, has been studied. The discharge has been analyzed by mass spectrometry (MS) and optical emission spectroscopy (OES) for varying amounts of oxygen in the gas mixture both in the presence and in the absence of argon. The films obtained have been characterized by Fourier transform infrared (FTIR) and X‐ray photoelectron spectroscopy (XPS). It is found that the electron impact of the TMS molecules and their dissociative ionization play an important role in the deposition process. Si(OH)x(CH3)3–x species, produced by reactions between the Si(CH3)4 molecule and Si(CH3)3+ ion fragments with O and O2, have been identified as important reaction intermediates. Such species form in different proportions depending on the O2/TMS ratio in the gas mixture. It is proposed that their incorporation onto the surface of the growing films accounts for the wide range of compositions achieved (ranging from SiO2 to almost Si:C:H) and the high concentration of Si‐C bonds experimentally detected in the SiOxCyHz thin films.
Neural bandwidth allocation function (NBAF) control scheme at WiMAX MAC layer interface
Authors: Marchese Mario , Mongelli Maurizio
Published: December 2006

The paper proposes a bandwidth allocation scheme to be applied at the interface between upper layers (IP, in this paper) andMedium Access Control(MAC) layer over IEEE 802.16 protocol stack. The aim is to optimally tune the resource allocation to match objective QoS (Quality of Service) requirements. Traffic flows characterized by different performance requirements at the IP layer are conveyed to the IEEE 802.16 MAC layer. This process leads to the need for providing the necessary bandwidth at the MAC layer so that the traffic flow can receive the requested QoS.

The proposed control algorithm is based on real measures processed by a neural network and it is studied within the framework of optimal bandwidth allocation andCall Admission Controlin the presence of statistically heterogeneous flows. Specific implementation details are provided to match the application of the control algorithm by using the existing features of 802.16 request–grant protocol acting at MAC layer. The performance evaluation reported in the paper shows the quick reaction of the bandwidth allocation scheme to traffic variations and the advantage provided in the number of accepted calls. Copyright © 2006 John Wiley & Sons, Ltd.
Phospholipase Cγ negatively regulates Rac/Cdc42 activation in antigen‐stimulated mast cells
Authors: El‐Sibai Mirvat , Backer Jonathan M.
Published: December 2006

The Rho GTPases Rac and Cdc42 play a central role in the regulation of secretory and cytoskeletal responses in antigen‐stimulated mast cells. In this study, we examine the kinetics and mechanism of Rac and Cdc42 activation in the rat basophilic leukemia RBL‐2H3 cells. The activation kinetics of both Rac and Cdc42 show a biphasic profile, consisting of an early transient peak at 1 min and a late sustained activation phase at 20–40 min. The inhibition of phospholipase C (PLC)γ causes a twofold increase in Rac and Cdc42 activation that coincides with a dramatic production of atypical filopodia‐like structures. Inhibition of protein kinase C using bisindolylmaleimide mimics the effect of PLCγ inhibition on Rac activation, but not on Cdc42 activation. In contrast, depletion of intracellular calcium leads to a complete inhibition of the early activation peak of both Rac and Cdc42, without significant effects on the late sustained activation. These data suggest that PLCγ is involved in a negative feedback loop that leads to the inhibition of Rac and Cdc42. They also suggest that the presence of intracellular calcium is a prerequisite for both Rac and Cdc42 activation.
CD4+CD25high regulatory T cells reduce T cell transendothelial migration in cancer patients
Authors: Enarsson Karin , Lundin B. Samuel , Johnsson Erik , Brezicka Thomas , Quiding‐Järbrink Marianne
Published: December 2006

Cell‐mediated immunity is thought to be the main mechanism of anti‐tumour responses of the host, but it is not known if cancer disease affects T cell recruitment from blood to tissues. Therefore, we compared Heliobacter pylori‐induced T cell transendothelial migration (TEM) in H. pylori‐infected gastric carcinoma patients, colon and lung carcinoma patients and healthy volunteers. H. pylori induced significant T cell migration from all groups. However, there was a dramatic reduction of T cell TEM in gastric carcinoma patients (80%) compared to healthy individuals. A similarly reduced transmigration was also seen in colon and lung carcinoma patients. We found significantly increased frequencies of Treg cells in the blood of gastric carcinoma patients compared to healthy individuals, and depletion of Treg cells from the blood of these patients prior to TEM restored T cell migration. The effect of Treg cells was largely dependent on cell‐cell contact, but not on IL‐10 or TGF‐β. In addition, the presence of Treg cells led to reduced T cell attachment to endothelium and decreased production of T cell‐recruiting chemokines during TEM. In conclusion, Treg cell‐mediated reduction of T cell TEM may reduce T cell recruitment in patients with epithelial malignancies, thereby hampering anti‐tumour responses.
Regulation of intestinal immunity: Effects of the oral adjuvant Escherichia coli heat‐labile enterotoxin on migrating dendritic cells
Authors: Milling Simon W. F. , Yrlid Ulf , Jenkins Chris , Richards Claire M. , Williams Neil A. , MacPherson Gordon
Published: December 2006

Escherichia coli heat‐labile enterotoxin (Etx) is an oral adjuvant in mice. We show that this is also true for rats. To understand this adjuvant activity we examined lymph dendritic cells (DC) migrating from the intestine to mesenteric lymph nodes (MLN) in animals fed Etx. These DC can prime antigen‐specific antibody responses. We show that in rats the small intestine contains 7–24 million DC and 8 × 105 of these migrate to MLN each day. Surprisingly, Etx does not stimulate increased migration of lymph DC. However, oral Etx affects the activation, antigen transport and localization of migratory DC. Specifically, expression of CD25 increases on the CD172ahigh subset of lymph DC. Oral Etx also increases the number of CD172ahigh lymph DC containing co‐administered ovalbumin. CD172ahigh lymph DC treated with Etx in vitro, or purified from the lymph of animals fed Etx, stimulate stronger proliferative responses from primed T cells. Etx also directs more of the CD172ahigh lymph DC into the central region of the MLN T cell areas. This change in DC localization is associated with an increase in the expression of CCR7. These data help advance our understanding of the role of DC in initiating mucosal immune responses in vivo.
CD8+ suppressor‐mediated regulation of human CD4+ T cell responses to glutamic acid decarboxylase 65
Authors: James Eddie A. , Kwok William W.
Published: December 2006

Although potentially autoreactive T cells are present even in healthy subjects, most individuals do not develop autoimmune disease. It has been well demonstrated that CD4+CD25+ regulatory T cells play a significant role in controlling the expansion of autoreactive T cells in the periphery. However, some healthy individuals exhibit measurable responses to self peptide even in the presence of CD4+CD25+ regulatory cells. This article describes the regulation of human CD4+ T cell responses to glutamic acid decarboxylase 65 (GAD65), an autoantigen implicated in type‐1 diabetes, by autologous CD8+ suppressor T cells. In cells cultured from healthy individuals, the inclusion of autologous CD8+ T cells at physiological levels resulted in a dramatic decrease in the magnitude of in vitro CD4+ T cell responses to GAD65 peptide. Based on transwell experiments, the observed suppression was cell contact‐dependent. However, antibody blocking studies indicated that suppression was mediated by IL‐10. Cell fractionation studies suggested that CD8+ suppressor T cells originate from the CD45RA+CD27– population. The suppression of CD4+ T cell responses to GAD65 in healthy individuals raises the possibility that CD8+ suppressor T cells play an important role in controlling potentially autoreactive T cells in the general population.
IL‐10 inhibits endothelium‐dependent T cell costimulation by up‐regulation of ILT3/4 in human vascular endothelial cells
Authors: Gleissner Christian A. , Zastrow Arne , Klingenberg Roland , Kluger Martin S. , Konstandin Mathias , Celik Sultan , Haemmerling Susanne , Shankar Vijay , Giese Thomas , Katus Hugo A. , Dengler Thomas J.
Published: December 2006

Effects of IL‐10 on endothelium‐dependent T cell activation have not been investigated in detail. We confirm expression of the IL‐10 receptor and effective signaling via STAT‐3 in human umbilical vein endothelial cells (HUVEC). In CD4 T cell cocultures with HUVEC, pretreatment of endothelial cells with IL‐10 resulted in significant dose‐dependent inhibition of CD4 T cell proliferation, which also occurred when IL‐10 was removed after pretreatment before starting cocultures. Th1/Th2 polarization of proliferated T cells, endothelial nitric oxide (NO), or IL‐12 production were unchanged. However, IL‐10 stimulation resulted in up‐regulation of SOCS‐3, a negative regulator of cytokine secretion, and induction of the inhibitory surface molecules immunoglobulin‐like transcript 3 and 4 (ILT3/ILT4) in EC, potentially involving glucocorticoid‐induced leucine zipper (GILZ). Addition of blocking antibodies against ILT3/ILT4 to EC/T cell cocultures resulted in nearly complete reestablishment of T cell proliferation. In contrast, addition of soluble ILT3 or overexpression of ILT3 in cocultures significantly reduced T cell proliferation. No induction of foxp3+ regulatory T cells was seen. In conclusion, the T cell costimulatory potential of human EC is markedly suppressed by IL‐10 due to up‐regulation of ILT3/ILT4, obviously not involving generation of Treg. This identifies a novel action of IL‐10 in EC and a potential therapeutical target for local immunomodulation.
Stimuli that enhance IgA class switching increase histone 3 acetylation at Sα, but poorly stimulate sequential switching from IgG2b
Authors: Kaminski Denise A. , Stavnezer Janet
Published: December 2006

Germ‐line (GL) α transcription can be induced in mouse splenic B cells by LPS and TGF‐β. This stimulation results in ∼1% IgA+ cells, which can be increased by IL‐4, IL‐5, and anti‐IgD dextran (αδDex). To determine the mechanism of this increase, we asked whether IgA class switching correlates with acetylation of histone 3 at Sα, the switch region for IgA. In the presence of the survival factor B lymphocyte stimulator (BLyS), acetylated histone 3 (AcH3) at Sα was changed little by TGF‐β in LPS‐stimulated mouse splenic B cell cultures, despite induction of GLα RNA. Compared with BLyS/LPS/TGF‐β alone, treatment with BLyS/LPS/TGF‐β/IL‐4/IL‐5/αδDex increased AcH3 at Sα fourfold, and also increased GLα RNA levels more than eightfold. By contrast, IgG2b class switching was optimal in BLyS/LPS/TGF‐β alone, and was suppressed by IL‐4/IL‐5/αδDex. Thus, B cell activators that increase IgA class switching do not increase IgG2b class switching. Further investigation showed that in contrast to purified IgM+ cells, IgG2b+ cells switched poorly to IgA in response to BLyS/LPS/TGF‐β/IL‐4/IL‐5/ ± αδDex. These results suggest that IgA class switching is unusual among isotypes in its requirement for multiple B cell activation signals in addition to LPS and the cytokine that initiates the corresponding GL transcription.
Dinuclear Metallocenes with a Modulated Biphenylene Bridge for Olefin Polymerization
Authors: Kim Seong Kyun , Kim Hwa Kyu , Lee Min Hyung , Yoon Seung Woong , Han Yonggyu , Park Sungjin , Lee Junseong , Do Youngkyu
Published: December 2006

Dinuclear group 4 metallocene catalysts linked by a biphenylene or 1,2‐diphenylethylene bridge, namely [4,4′‐(C5Me4)2(C6H4)2][CpZrCl2]2 (2a), [p‐(C5Me4)C6H4CH2]2[CpZrCl2]2 (2b), [p‐(3,4‐Me2C5H2)C6H4CH2]2[CpZrCl2]2 (2c), [(C5Me4)2(C6H4)2][TiCl3]2 (3a), [p‐(C5Me4)C6H4CH2]2[TiCl3]2 (3b), and [p‐(3,4‐Me2C5H2)C6H4CH2]2[TiCl3]2 (3c), have been prepared and the crystal structures of 2b and 3b determined by X‐ray diffraction methods. The crystal structures reveal that these complexes consist of two equivalent metal units inverted with respect to the center of the bridge. All the complexes were tested for the polymerization of ethylene and styrene in the presence of methylaluminoxane (MAO), and direct comparisons of their catalytic properties with those of the corresponding mononuclear analogues [(PhC5Me4)CpZrCl2] (4a), [(p‐TolC5Me4)CpZrCl2] (4b), [(1‐p‐Tol‐3,4‐Me2C5H2)CpZrCl2] (4c), [(PhC5Me4)TiCl3] (5a), [(p‐TolC5Me4)TiCl3] (5b), and [(1‐p‐Tol‐3,4‐Me2C5H2)TiCl3] (5c) were performed. The dinuclear zirconocenes show a high activity in ethylene polymerization comparable with those of the corresponding mononuclear catalysts and give an increased molecular weight of polyethylene. The dinuclear half‐sandwich titanocenes exhibit similar or slightly lower activity and molecular weight in styrene polymerization compared with their mononuclear analogues. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Blue‐Light‐Emitting Complexes: Cationic (2‐Phenylpyridinato)iridium(III) Complexes with Strong‐Field Ancillary Ligands
Authors: Shik Chin Chong , Eum Min‐Sik , yi Kim Song , Kim Choongil , Kwon Kang Sung
Published: December 2006

The emission λmax are strikingly shorter (451, 482 nm) for the cationic dicarbonyl complex [Ir(ppy)2(CO)2]+ (2a) than those (473, 495 nm) of the anionic dicyano complex [Ir(ppy)2(CN)2]–, where CO and CN– are both sp carbon coordinating ligands and known to be strong‐field ligands showing a high trans effect. Sky‐blue‐light emission (λmax = 441–443 and 470–471 nm) could be obtained by modifying the ppy ligand to F2Meppy (2,4‐difluoro‐2‐phenyl‐m‐methylpyridinato anion) to prepare [Ir(F2Meppy)2LL′]+ [LL′ = (CO)2 (2aF2Me), (PPh2Me)2 (2bF2Me)]. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis of the η2‐1‐Phosphaallene Complexes [(η5‐C5H5)(CO)(NO)W{η2‐R1P=C=C(R2)H}] (R1 = tBu, Cy; R2 = Ph, H) from [(η5‐C5H5)(CO)(NO)W=C=C(R2)H] (R2 = Ph, H) and Inversely Polarized Phosphaalkenes R1P=C(NMe2)2 (R1 = tBu, Cy), and Their Structure
Authors: Weber Lothar , Noveski Gabriel , Braun Thomas , Stammler Hans‐Georg , Neumann Beate
Published: December 2006

The reaction of the vinylidene complex [(η5‐C5H5)(CO)(NO)W=C=C(H)Ph] (9) with the phosphaalkenes RP=C(NMe2)2 (1a: R = tBu; 1c: R = c‐C6H11) affords the novel η2‐1‐phosphaallene complexes [η2‐{RP=C=C(H)Ph}W(CO)(NO)(η5‐C5H5)] (14: R = tBu; 15: R = c‐C6H11) in addition to the carbene complex [(η5‐C5H5)(CO)(NO)W=C(NMe2)C(Ph)=C(H)NMe2] (16). Similarly, treatment of [(η5‐C5H5)(CO)(NO)W=C=CH2] (12) with the phosphaalkenes gives rise to the formation of [η2‐{RP=C=CH2}W(CO)(NO)(η5‐C5H5)] (17: R = tBu; 18: R = c‐C6H11). The novel compounds 14, 15, 17, and 18 were characterized by elemental analysis and by spectroscopy (IR, 1H, 13C NMR, MS). Moreover, the molecular structures of 14 and 16 were determined by X‐ray diffraction analyses. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Ex‐Chiral‐Pool Synthesis of β‐Hydroxyphosphonate Nucleoside Analogues
Authors: Gallier Franck , Peyrottes Suzanne , Périgaud Christian
Published: December 2006

A new series of mononucleotide analogues bearing a nonhydrolysable P–C bond instead of the P–O phosphate linkage is presented. We intend to set up an approach that allows the synthesis of β‐hydroxyphosphonate nucleoside analogues as a single diastereoisomer. In this respect, the key “sugar‐phosphonate” intermediate was obtained through an Arbusov reaction from an iodosugar derivative in which the stereochemistry of the β‐hydroxy group is determined by the choice of the starting material and remains in the resulting nucleotide analogues. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Concave Pyridines for Bifunctional Acid–Base Catalysis
Authors: Liebig Timo , Abbass Michael , Lüning Ulrich
Published: December 2006

Two bifunctional concave acid–base catalysts, 1 and 2, have been synthesized starting from 2,6‐dibromopyridine (9) and 2,6‐bis(ω‐alkenyloxy)phenylboronic acids 8 and 10 which end up as bridgeheads in final bimacrocycles 1 and 2. One bridgehead contained an additional substituent in the 4‐position. The respective protected 4‐hydroxymethyl‐substituted phenylboronic acids 8 were synthesized from 4‐bromo‐3,5‐dihydroxybenzoic acid (3) in five steps. 4‐Unsubstituted boronic acid 10 and 4‐substituted boronic acid 8 were then attached to 9 by subsequent Suzuki couplings to give tetra‐ω‐alkenes 12. By ring‐closing metathesis of 12, bimacrocyclic dienes 13 and 17 were formed. After deprotection of the 4‐hydroxymethyl group of one bridgehead, a 3‐hydroxybenzoate was coupled to 14 to give ester 15 which gave bifunctional acid–base catalyst 1 upon hydrolysis. Analogously, homologue 2 was synthesized, but before coupling the bimacrocycle to the benzoate, tetraene 14 was hydrogenated to 18. Acidic and basic centers in 1 (49 % from 9) and 2 (19 % from 9) are at least 5 Å apart.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Concave Imidazolinium Salts as Precursors to Concave N‐Heterocyclic Carbenes
Authors: Winkelmann Ole , Näther Christian , Lüning Ulrich
Published: December 2006

Concave bimacrocyclic imidazolinium ions 8 have been synthesized as precursors for N‐heterocyclic carbenes 9 (NHC) in 13 to 29 % overall yields based on 2‐nitroresorcinol (1). As bridgeheads, 2,6‐bis(ω‐alkenyloxy)anilines 3 have been synthesized from 1. Reaction of 3 with oxalyl chloride, reduction to respective diamines 5, and ring closure with triethyl orthoformate gave N,N‐diaryl‐substituted imidazolinium ions 6. The terminal vinyl groups were connected by ring‐closing metathesis to give bimacrocyclic imidazolinium ions 7, whose alkene functions were hydrogenated to give saturated bimacrocyles 8. The structure of 8a was elucidated by X‐ray analysis. The respective NHC 9 was generated by deprotonation with potassium tert‐butoxide, and 9 was scavenged with CS2 to give adduct 10. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
The First Catalytic Method for Heck Alkynylation of Unactivated Aryl Bromides (Copper‐Free Sonogashira) in an Ionic Liquid: 1 mol‐% Palladium/Triphenylphosphane/Pyrrolidine in [BMIM][BF4] as a Simple, Inexpensive and Recyclable System
Authors: Hierso Jean‐Cyrille , Boudon Julien , Picquet Michel , Meunier Philippe
Published: December 2006

Herein we report the studies of Heck alkynylation (copper‐free Sonogashira) with aryl halides (I, Br, Cl) employing various metallic precursors, tertiary phosphanes and bases in [BMIM][BF4] as the solvent. As a result, we provide the first method that allows the coupling of a large array of substrates, either activated or deactivated bromides in an ionic liquid. Furthermore, the system of highest efficiency is unexpectedly the simplest and cheaper combination that employs [Pd(η3‐C3H5)Cl]2/PPh3 at only a 1 mol‐% loading with pyrrolidine as the base and in the absence of a copper salt. The coupling of sterically and electronically deactivated bromides bearing different functional groups to aryl‐ and alkyl acetylenes, as well as the possibility of recycling, make these results of high interest to the future development of Heck‐ and Sonogashira‐type reactions in ionic liquids.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Flow Injection Analysis of Chloramphenicol by Using a Disposable Wall‐Jet Ring Disk Carbon Electrode
Authors: Liao Chun‐Yen , Chang Chia‐Chen , Ay Chyung , Zen Jyh‐Myng
Published: December 2006

A preanodized screen‐printed ring disk carbon electrode was applied to the determination of chloramphenicol (PhNO2, CAP) by flow injection analysis (FIA). By setting up the first irreversible reduction reaction of PhNO2 to PhNHOH at the disk electrode, the following reversible oxidation of hydroxylamine (PhNHOH) to the nitroso (PhNO) derivative can be monitored/collected at the ring electrode for CAP analysis. The interference from dissolved oxygen and others can thus be avoided by using this approach and precise CAP determination can be easily performed by FIA under aerobic conditions. Preanodization treatment helps to lower the overpotential of the electrochemical reaction of CAP and favors the selective detection in aqueous medium. Under the optimum conditions, ten repetitive determinations at 1 μM and 10 μM CAP resulted in relative standard deviations of less than 4%, indicating good reproducibility of the system. A linear calibration range of 0.1–20 μM with a detection limit of 0.074 μM (S/N=3) was obtained. Veterinary pharmaceutics were finally analyzed by this sensor to validate its practical applicability.
Energy demands for seismic design against low‐cycle fatigue
Authors: Teran‐Gilmore Amador , Jirsa James O.
Published: December 2006

A seismic design procedure that does not take into account the maximum and cumulative plastic deformation demands that a structure is likely to undergo during severe ground motion could lead to unsatisfactory performance. In spite of this, current design procedures do not take into account explicitly the effect of low‐cycle fatigue. Based on the high correlation that exists between the strength reduction factor and the energy demand in earthquake‐resistant structures, simple procedures can be formulated to estimate the cumulative plastic deformation demands for design purposes. Several issues should be addressed during the use of plastic energy within a practical performance‐based seismic design methodology. Copyright © 2006 John Wiley & Sons, Ltd.
Typification of specific and infraspecific names in Abies, Larix, Picea, and Pinus (Pinaceae)
Authors: Christensen K. I. , Orlova L. V.
Published: December 2006

In connection with systematic studies of the genera Abies, Larix, Picea, and Pinus (Pinaceae) lectotypes are designated for Abies pinsapo var. baborensis, Larix × czekanowskii (= L. gmelinii × L. sibirica), Larix dahurica, L. griffithii, Picea abies var. arctica, P. maximowiczii, P. schrenkiana, Pinus brunoniana (≡ Tsuga brunoniana), P. canariensis, P. coronans, P. × neilreichiana (= P. nigra × P. sylvestris), P. smithiana (≡ Picea smithiana), and P. sylvestris vars. baliosperma, leucosperma, melanocarpa, mongolica, and phaeosperma. Lectotypes and epitypes are designated for Pinus pumilio var. applanata and P. uncinata var. rotundata f. mughoides, as well as an epitype for P. mugo. Furthermore, various original material has been located for Abies sibirica, Pinus altamiranoi, P. ayachahuite, P. khasya, P. × litvinovii (P. sylvestris × tabulae‐formis), P. pityusa, and P. pringlei, as well as Tsuga longibracteata (≡ Nothotsuga longibracteata). (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Seed banks in an inundation gradient of two grasslands in the 10th Region (Chile) and their relationship with the plant cover
Authors: Alvarez M. , Ramírez C. , Figueroa H. , San Martín C.
Published: December 2006

The vegetation and the seed banks of two adjacent grassland communities, a dry one (Hyperico‐Agrostietum) and a humid one (Juncetum proceri), of the 10th Region of Chile were compared. The vegetal cover was estimated in percentage, whereas the density of the seed banks was estimated using two different methods: tray germination in a greenhouse and direct count. In contradiction to the above ground plant cover, the floristic compositions of the seed banks of both grasslands cannot be differentiated by correspondence analysis. Nevertheless all the seed bank samples resemble much more the vegetation of the humid Juncetum proceri grassland, because of the preferential flow of diaspores from the humid grassland towards the dry one. A greater seed density was detected in the humid Juncetum proceri grassland, perhaps due to its greater production of diaspores and due to the fact that high soil humidity retain the seeds longer viable. The germination method displayed a greater efficiency in the detection of seeds, that due to the high amount of small seeds (mainly of Juncus spp.). (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Kikuyuochloa, genus novum (Poaceae: Paniceae)
Authors: Scholz H.
Published: December 2006

The new monotypic genus Kikuyuochloa, based on Pennisetum clandestinum, is erected. Contrary to the common view in Pennisetum clandestinum (Kikuyuochloa clandestina) 1–4(–6) unispiculate inflorescences each subtended by bristles are grouped in one cluster, the cluster representing the real inflorescence unit homologous to the partial inflorescence of Pennisetum. A basal bristled involucrum is absent in Kikuyuochloa; the bristle configuration beneath the individual spikelets of Kikuyuochloa is not comparable to the bristled involucrum of Pennisetum. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Two new species of CousiniaCass. of sect. StenocephalaeBunge from Iran
Authors: Djavadi S. B. , Attar F.
Published: December 2006

Cousinia cordifolia Djavadi & Attar., sp. nova and C. persica Djavadi & Attar, sp. nova are described as two new species of sect. Stenocephalae. These species are compared with their closest relatives. Illustrations and geographical distribution are also presented. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Exomorphic seed characters of some species of the Apocynaceae s.l. in Egypt
Authors: Al Nawaihi A. S. , Hassan S. A. , Elwan Z. A.
Published: December 2006

Exomorphic seed characters of 18 species of the Apocynaceae s.l. were investigated for an evidence to support or to oppose its taxonomic treatment as suggested by Endress & Bruyns (2000). It was found that some characters fluctuated through different expressions in different taxa. These were shape of the seed, and the reticulate sculpture of the seed coat. Some other characters showed a relative consistency at the sub‐familial level. The latter characters were the seed coma, the concavity or convexity of the periclinal walls and the channeling of various depths of the anticlinal walls. It was concluded that such gradation in characters and character states on one hand and the relative consistency of some of them on the other hand may promote further investigation on the seed exomorphic characters in a large sample for an additional evidence to the supports or non supports to a large Apocynaceae, or to the elimination of some of its taxa to form the apomorphic derivative Asclepiadaceae. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rediscovery of Achillea boissieriHausskn. ex Boiss. later 140 years
Authors: Arabacı T. , Yıldız B.
Published: December 2006

This study includes taxonomical improvements of Achillea boissieri Hausskn. ex Boiss. and distributions in Turkey which was known only from the type specimen and regarded as a synonym in relevant studies. After collected second times from the field, A. boissieri decided as a separate species. Furthermore, description, localities, distribution map and key of allied species are given. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Two new species of Scrophularia L. (Scrophu‐lariaceae) from Iran
Authors: Attar F. , Hamzeh'ee B.
Published: December 2006

Two new species of Scrophularia L. (S. shulabadensis Attar & Hamzeh'ee, sp. nova and S. gharemannii Attar & Hamzeh'ee, sp. nova) are described and illustrated from Southwest and South of Iran. The affinities of these two new endemic species are discussed with the related species. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pollenmorphology of the Egyptian species of genusLimoniumMill. (Plumbaginaceae)
Authors: Osman A. K. , El‐Garf I. A.
Published: December 2006

Stigma and pollen types are reviewed in eight species of genusLimoniumby light and scanning microscopy. A careful examination of most Egyptian species ofLimoniumreveals that this genus is distinctly dimorphic in stigma and pollen types. On the basis of the stigma type and the exine pattern, two distinct pollen types are recognized viz., Pollen type‐A (comprisesLimonium axillareandL. meyeri) and Pollen type‐B (comprises the rest studied species ofLimonium). Description of each type, a key to the investigated taxa as well as LM and SEM micrographs of pollen grains are provided. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Generic disposition of Vicatia bipinnata in Melanosciadium and a new species (Umbelliferae)
Authors: Pimenov M. G. , Kljuykov E. V.
Published: December 2006

Taxonomically critical Chinese species Vicatia bipinnata, treated early also in the genus Sino‐dielsia, found to be morphologically similar to Melanosciadium H.Boissieu, a previously monotypic genus, also endemic to China. A new combination in Melanosciadium [M. bipinnatum (Shan RenHwa & Pu FaTing ex Shan Ren‐Hwa et al.) Pimenov & Kljuykov] has been proposed. A new species, Melanosciadium genuflexum Pimenov & Kljuykov, closely related to M. bipinnatum has been described. A key to determination of three species of Melanosciadium has been compiled. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A new species of LinariaMill. sect. LinariaMill. (Scrophulariaceae‐Antirrhineae) from Iran
Authors: Hamdi S. M. M. , Assadi M. , Zarre Sh. , Aghabeigi F.
Published: December 2006

Linaria guilanensis S.M.M.Hamdi & M.Assadi, sp. nova of Scrophulariaceae is described as new species from Guilan province respectively. This species belong to the section Linaria Mill. The new species is compared to their closest relative L. lineo‐lata Boiss. L. guilanensis is similar to L. lineolata Boiss. (1853) in having pedicel length, spur, leaves shape and the length of calyx‐lobes. This species differs from L. lineolata in having a shorter corolla (vs. 15–17 × 3.5–5 mm long), shorter bracts (vs. 1.5–3 mm long), shorter capsule (vs. 1.5–3 × 4.5– 5 mm long), shorter style (vs. 6.5–7 mm long), shorter long stamen (vs. 8 mm long), shorter short stamen (vs. 6 mm long), narrower calyx lobes (vs. 1.2–2 mm long) and different microsculpturing pattern of the testa cells. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A control volume finite‐element method for numerical simulating incompressible fluid flows without pressure correction
Authors: Omri Ahmed , Hajri Imene , Nasrallah Sassi Ben
Published: December 2006

This paper presents a numerical model to study the laminar flows induced in confined spaces by natural convection. A control volume finite‐element method (CVFEM) with equal‐order meshing is employed to discretize the governing equations in the pressure–velocity formulation. In the proposed model, unknown variables are calculated in the same grid system using different specific interpolation functions without pressure correction. To manage memory storage requirements, a data storage format is developed for generated sparse banded matrices. The performance of various Krylov techniques, including Bi‐CGSTAB (Bi‐Conjugate Gradient STABilized) with an incomplete LU (ILU) factorization preconditioner is verified by applying it to three well‐known test problems. The results are compared to those of independent numerical or theoretical solutions in literature. The iterative computer procedure is improved by using a coupled strategy, which consists of solving simultaneously the momentum and the continuity equation transformed in a pressure equation. Results show that the strategy provides useful benefits with respect to both reduction of storage requirements and central processing unit runtime. Copyright © 2006 John Wiley & Sons, Ltd.
Numerical study of wave propagation in compressible two‐phase flow
Authors: Zeidan D. , Romenski E. , Slaouti A. , Toro E. F.
Published: December 2006

We propose a new model and a solution method for two‐phase two‐fluid compressible flows. The model involves six equations obtained from conservation principles applied to a one‐dimensional flow of gas and liquid mixture completed by additional closure governing equations. The model is valid for pure fluids as well as for fluid mixtures. The system of partial differential equations with source terms is hyperbolic and has conservative form. Hyperbolicity is obtained using the principles of extended thermodynamics. Features of the model include the existence of real eigenvalues and a complete set of independent eigenvectors. Its numerical solution poses several difficulties. The model possesses a large number of acoustic and convective waves and it is not easy to upwind all of these accurately and simply. In this paper we use relatively modern shock‐capturing methods of a centred‐type such as the total variation diminishing (TVD) slope limiter centre (SLIC) scheme which solve these problems in a simple way and with good accuracy. Several numerical test problems are displayed in order to highlight the efficiency of the study we propose. The scheme provides reliable results, is able to compute strong shock waves and deals with complex equations of state. Copyright © 2006 John Wiley & Sons, Ltd.
Seeing for yourself: feasibility study towards valuing visual impairment using simulation spectacles
Authors: Aballéa Samuel , Tsuchiya Aki
Published: December 2006

Elicitation of utilities from members of the public generally uses verbal description of health states. This paper reports the results of a small‐scale time trade‐off study on the feasibility of an alternative approach, where health states were simulated using plastic spectacles. This approach has methodological implications for the valuation exercise, in that many respondents find it difficult to conceive of visual impairment alone, without referring to their own current health. We conclude that it is feasible to simulate visual impairment in valuation exercises, but care must be taken to ensure what health state is effectively being valued. Copyright © 2006 John Wiley & Sons, Ltd.
Public versus private health care in a national health service
Authors: Brekke Kurt R. , Sørgard Lars
Published: December 2006

This paper studies the interaction between public and private health care provision in a National Health Service (NHS), with free public care and costly private care. The health authority decides whether or not to allow private provision and sets the public sector remuneration. The physicians allocate their time (effort) in the public and (if allowed) in the private sector based on the public wage income and the private sector profits. We show that allowing physician dual practice ‘crowds out’ public provision, and results in lower overall health care provision. While the health authority can mitigate this effect by offering a higher wage, we find that a ban on dual practice is more efficient if private sector competition is weak and public and private care are sufficiently close substitutes. On the other hand, if private sector competition is sufficiently tough, a mixed system, with physician dual practice, is always preferable to a pure NHS system. Copyright © 2006 John Wiley & Sons, Ltd.
Health‐related quality of life profiles based on survivorship status for head and neck cancer patients
Authors: Goldstein David P. , Hynds Karnell Lucy , Christensen Alan J. , Funk Gerry F.
Published: December 2006

Background.

As the methodologies for evaluating health‐related quality of life (HRQOL) in head and neck cancer patients have matured over the past 10 years, there has been an increasing focus on reporting longitudinal data. These studies have primarily focused on long‐term survivors. This study addresses the HRQOL of both long‐term and short‐term survivors.

Methods.

This is a prospective, longitudinal study of 479 head and neck cancer patients followed for at least 3 years after diagnosis. Analysis of longitudinally collected HRQOL scores was based on survivorship status.

Results.

The HRQOL for 3 survivorship groups: short‐term (died <1 year), intermediate‐term (died 1‐3 years), and long‐term survivors (alive >3 years) were different at all time points (pretreatment, 3, 6, and 12 months). Differences were greatest between the short‐term and long‐term survivors. Long‐term survivors demonstrated the best HRQOL and an improving HRQOL trajectory at 12 months. The HRQOL of short‐term survivors declined precipitously throughout all available follow‐up. Intermediate‐term survivors did show some improvement following treatment but had a declining HRQOL trajectory at 12 months.

Conclusion.

The HRQOL profiles of head and neck cancer patients differed significantly depending on survivorship status. Long‐term HRQOL results should be analyzed within the context of the results for all of the patients eligible to have been included in the initial study cohort. © 2006 Wiley Periodicals, Inc. Head Neck, 2007.