bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal replenishment policy for imperfect quality EMQ model with rework and backlogging
Authors: Wang Chiu Singa
Published: November 2006

This paper derives the optimal replenishment policy for imperfect quality economic manufacturing quantity (EMQ) model with rework and backlogging. The classic EMQ model assumes that all items produced are of perfect quality. However, in real‐life manufacturing settings, generation of imperfect quality items is almost inevitable. In this study, a random defective rate is assumed. All items produced are inspected and the defective items are classified as scrap and repairable. A rework process is involved in each production run when regular manufacturing process ends, and a rate of failure in repair is also assumed. Unit disposal cost and unit repairing and holding costs are included in our mathematical modelling and analysis. The renewal reward theorem is employed in this study to cope with the variable cycle length. The optimal replenishment policy in terms of lot‐size and backlogging level that minimizes expected overall costs for the proposed imperfect quality EMQ model is derived. Special cases of the model are identified and discussed. Numerical example is provided to demonstrate its practical usage. Copyright © 2006 John Wiley & Sons, Ltd.
Comparison of the hydrolysis of polyethylene terephthalate fibers by a hydrolase from Fusarium oxysporum LCH I and Fusarium solani f. sp. pisi
Authors: Nimchua Thidarat , Punnapayak Hunsa , Zimmermann Wolfgang
Published: November 2006

The hydrolysis of polyethylene terephthalate (PET) fibers by two fungal hydrolases was investigated. The hydrolase from a newly isolated Fusarium oxysporum strain (LCH 1) was more efficient in releasing terephthalic acid from PET fibers compared to the enzyme from F. solani f. sp. pisi DSM 62420 when equal amounts of p‐nitrophenyl butyrate‐hydrolyzing activity were employed. PET fabrics treated under the same conditions with the enzyme from F. oxysporum LCH 1 also showed a considerably higher increase in hydrophilicity compared to fabrics treated with the enzyme from F. solani f. sp. pisi DSM 62420.
Bioreactor technology: A novel industrial tool for high‐tech production of bioactive molecules and biopharmaceuticals from plant roots
Authors: Sivakumar Ganapathy
Published: November 2006

Plants are the richest source for different bioactive molecules. Because of the vast number of side effects associated with synthetic pharmaceuticals, medical biotechnologists turned to nature to provide new promising therapeutic molecules from plant biofactories. The large‐scale availability of the disease‐ and pesticide‐free raw material is, however, restricted in vivo. Many bioactive plant secondary metabolites are accumulated in roots. Engineered plants can also produce human therapeutic proteins. Vaccines and diagnostic monoclonal antibodies can be won from their roots, so that engineered plants hold immense potential for the biopharmaceutical industry. To obtain sufficient amounts of the plant bioactive molecules for application in human therapy, adventitious and hairy roots have to be cultured in in vitro systems. High‐tech pilot‐scale bioreactor technology for the establishment of a long‐term adventitious root culture from biopharmaceutical plants has recently been established. In this review, I briefly discuss a technology for cultivating bioactive molecule‐rich adventitious and hairy roots from plants using a high‐tech bioreactor system, as well as the principles and application of genome‐restructuring mechanisms for plant‐based biopharmaceutical production from roots. High‐tech bioreactor‐derived bioactive phytomolecules and biopharmaceuticals hold the prospect of providing permanent remedies for improving human well‐being.
Impact of denaturation with urea on recombinant apolipoprotein A‐IMilano ion‐exchange adsorption: Equilibrium uptake behavior and protein mass transfer kinetics
Authors: Hunter Alan K. , Suda Eric J. , Das Tapan K. , Shell Robert E. , Herberg John T. , Ramasubramanyan Natraj , Gustafson Mark E. , Ho Sa V.
Published: November 2006

We have studied the equilibrium uptake behavior and mass transfer rate of recombinant apolipoprotein A‐IMilano (apo A‐IM) on Q Sepharose HP under non‐denaturing, partially denaturing, and fully denaturing conditions. The protein of interest in this study is composed of amphipathic α helices that serve to solubilize and transport lipids. The dual nature of this molecule leads to the formation of micellar‐like structures and self association in solution. Under non‐denaturing conditions equilibrium uptake is 134 mg/mL media and the isotherm is essentially rectangular. When fully denatured with 6 M urea, the equilibrium binding capacity decreases to 25 mg/mL media and the isotherm becomes less favorable. The decrease in both binding affinity and media capacity when the protein is completely denatured with 6 M urea can be explained by the loss of all alpha helical structure. The rate of apo A‐IM mass transfer on Q Sepharose HP was characterized using a macropore diffusion model. Results of modeling studies indicate that effective pore diffusivity increases from 4.5 x 10–9 cm2/s in the absence of urea to 6.0 x 10–8 cm2/s when apo A‐IM is fully denatured with 6 M urea. Based on light‐scattering data reported for apo A‐I, protein self association appears to be the dominant cause of slow protein mass transfer observed under non‐denaturing conditions.
Utilization of renewables for lactic acid fermentation
Authors: Venus Joachim
Published: November 2006

Originally, lactic acid was produced from pure substrates like glucose. Increasingly, however, agricultural feedstocks such as grains and green biomass are also being used as raw materials for the biotechnological production of lactic acid. A high‐productivity lactic acid bacterium strain was selected, process parameters were optimized for the batch fermentation on a laboratory scale, and its performance at cultivation on a barley hydrolysate medium together with different supplements was examined. The present results for the cultivation of the Lactobacillus paracasei on complex nutrient broth are in the same range as those for another strain of the same species with pure glucose, de Man, Rogosa and Sharpe medium (MRS) minerals, peptone and yeast extract. Under these conditions, this strain was able to accumulate more than 100 g lactate/L in the MRS medium. Medium optimization experiments showed that the main part of the nitrogen‐containing nutrients in the medium (peptone, yeast extract) can be replaced by protein extracts from green biomass (lucerne green juice). The green juice after pressing fresh biomass contains a series of nitrogen‐containing compounds and inorganic salts, which are essential for cell growth. Thus, on laboratory scale, we have demonstrated that it is possible to substitute synthetic nutrients by renewable resources like cereals and green biomass without any loss of productivity. This high biomass concentration together with the number of living cells could increase the productivity to higher levels compared to the well‐adapted synthetic nutrients of MRS.
Engineered blood and lymphatic capillaries in 3‐D VEGF‐fibrin‐collagen matrices with interstitial flow
Authors: Helm Cara‐Lynn E. , Zisch Andreas , Swartz Melody A.
Published: November 2006

In vitro endothelial cell organization into capillaries is a long standing challenge of tissue engineering. We recently showed the utility of low level interstitial flow in guiding the organization of endothelial cells through a 3‐D fibrin matrix‐containing covalently bound vascular endothelial growth factor (VEGF). Here this synergistic phenomenon was extended to explore the effects of matrix composition on in vitro capillary morphogenesis of human blood versus lymphatic endothelial cells (BECs and LECs). Different mixtures of fibrin and collagen were used in conjunction with constant concentrations of matrix‐bound VEGF and slow interstitial flow over 10 days. Interestingly, the BECs and LECs each showed a distinct preference in terms of organization for matrix composition: LECs organized the most extensively in a fibrin‐only matrix, while BEC organization was optimized in the compliant collagen‐containing matrices. Furthermore, the BECs and LECs produced architecturally different structures; while BECs organized in thick, branched networks containing wide lumen, the LECs were elongated into slender, overlapping networks with fine lumen. These data demonstrate the importance of the 3‐D matrix composition in facilitating and coordinating BEC and LEC capillary morphogenesis, which is important for in vitro vascularization of engineered tissues. Biotechnol. Bioeng. 2007;96: 167–176. © 2006 Wiley Periodicals, Inc.
Molecular simulation of protein aggregation
Authors: Bratko Dusan , Cellmer Troy , Prausnitz John M. , Blanch Harvey W.
Published: November 2006

Computer simulation offers unique possibilities for investigating molecular‐level phenomena difficult to probe experimentally. Drawing from a wealth of studies concerning protein folding, computational studies of protein aggregation are emerging. These studies have been successful in capturing aspects of aggregation known from experiment and are being used to refine experimental methods aimed at abating aggregation. Here we review molecular‐simulation studies of protein aggregation conducted in our laboratory. Specific attention is devoted to issues with implications for biotechnology. Biotechnol. Bioeng. 2007;96: 1–8. © 2006 Wiley Periodicals, Inc.
Tetrabromocinnamic Acid (TBCA) and Related Compounds Represent a New Class of Specific Protein Kinase CK2 Inhibitors
Authors: Pagano Mario A. , Poletto Giorgia , Di Maira Giovanni , Cozza Giorgio , Ruzzene Maria , Sarno Stefania , Bain Jenny , Elliott Matthew , Moro Stefano , Zagotto Giuseppe , Meggio Flavio , Pinna Lorenzo A.
Published: November 2006

Abnormally high constitutive activity of protein kinase CK2, levels of which are elevated in a variety of tumours, is suspected to underlie its pathogenic potential. The most widely employed CK2 inhibitor is 4,5,6,7‐tetrabromobenzotriazole (TBB), which exhibits a comparable efficacy toward another kinase, DYRK1 a. Here we describe the development of a new class of CK2 inhibitors, conceptually derived from TBB, which have lost their potency toward DYRK1 a. In particular, tetrabromocinnamic acid (TBCA) inhibits CK2 five times more efficiently than TBB (IC50 values 0.11 and 0.56 μM, respectively), without having any comparable effect on DYRK1 a (IC50 24.5 μM) or on a panel of 28 protein kinases. The usefulness of TBCA for cellular studies has been validated by showing that it reduces the viability of Jurkat cells more efficiently than TBB through enhancement of apoptosis. Collectively taken, the reported data support the view that suitably derivatized tetrabromobenzene molecules may provide powerful reagents for dissecting the cellular functions of CK2 and counteracting its pathogenic potentials.
Learning from Directed Evolution: Further Lessons from Theoretical Investigations into Cooperative Mutations in Lipase Enantioselectivity
Authors: Reetz Manfred T. , Puls Michael , Carballeira José Daniel , Vogel Andreas , Jaeger Karl‐Erich , Eggert Thorsten , Thiel Walter , Bocola Marco , Otte Nikolaj
Published: November 2006

An earlier experimental study, which involved the directed evolution of enantioselective lipase variants from Pseudomonas aeruginosa as catalysts in the hydrolytic kinetic resolution of 2‐methyl‐decanoic acid p‐nitrophenyl ester, provided a mutant with six mutations. Consequently, the selectivity factor was found to increase from E=1.1 for the wild‐type to E=51 for the best mutant. Only one of the amino acid exchanges in this mutant was found to occur next to the binding pocket, the other mutations being remote. Our previous theoretical analysis with molecular‐dynamics simulations helped to unveil the source of enhanced enantioselectivity: a relay mechanism that involves two of the six mutations was shown to induce strong cooperativity. In this investigation, single, double, and triple mutants were constructed and tested as enantioselective catalysts. This study supports our original postulate regarding the relay mechanism, offers further mechanistic insight into the role of individual mutations, and provides mutants that display even higher enantioselectivity (E of up to 64).
An Unexpected New Optimum in the Structure Space of DNA Solubilizing Single‐Walled Carbon Nanotubes
Authors: Vogel Stephanie R. , Kappes Manfred M. , Hennrich Frank , Richert Clemens
Published: November 2006

Here we report quantitative data on the amount of single‐walled carbon nanotubes that can be suspended with oligodeoxynucleotides in aqueous buffer, together with rate constants for the thermal denaturation of the resulting DNA‐nanotube complexes at elevated temperatures. Sequence motifs d(GT)n and d(AC)n with n=2, 3, 5, 10, 20, or 40 were employed, both individually and as equimolar mixtures of the complementary strands. Unexpectedly, the greatest suspending efficiency was found for the mixture of short, complementary oligonucleotides d(GT)3 and d(AC)3. Unlike the suspending efficiency, the kinetic stability of the nanotube suspensions increases with increasing chain length of the DNA, with half life times of >25 h at 90 °C for the complexes of the longest strands. Our results identify a new, unexpected optimum in DNA sequence space for suspending carbon nanotubes. They also demonstrate that suspending power depends on the presence of complementary strands. Exploratory assays suggest that nanotubes can be deposited site‐selectively from suspensions formed with short DNA sequences.
Tuning of the Structures of Chiral Phosphane‐Phosphites: Application to the Highly Enantioselective Synthesis of α‐Acyloxy Phosphonates by Catalytic Hydrogenation
Authors: Rubio Miguel , Vargas Sergio , Suárez Andrés , Álvarez Eleuterio , Pizzano Antonio
Published: November 2006

A family of new chiral phosphane‐phosphites 5 has been prepared and employed in the synthesis of rhodium complexes of formulation [Rh(cod)(5)]BF4 (7). The use of bulky phosphane or phosphite groups in the preparation of 7 avoids the formation of undesired disubstituted complexes, one of which (9 a) has been isolated and characterized. Ligands 5 display important differences from the bulkier phosphane‐phosphites 1: complexes 7—unlike their rigid [Rh(cod)(1)]BF4 counterparts—show fluxional behaviour in solution, consistent with backbone oscillation around the coordination plane. A detailed screening of ligands 1 and 5 in catalytic asymmetric hydrogenations of enol phosphonates 12 demonstrated a critical influence of the steric characteristics of the phosphane‐phosphite in the course of the reaction, and optimization of the two phosphorus functionalities resulted in the production of versatile and efficient catalysts for this class of hydrogenations: enantioselectivities of up to 98 % ee were thus obtained with substrates bearing an alkyl substituent in the β‐position, while for their challenging aryl counterparts values of up to 92 % ee were achieved. The coordination mode of phosphonate 12 a towards a Rh phosphane‐phosphite fragment has also been investigated and a preference of the olefin fragment to occupy the position cis to the phosphite group has been observed. From this observation an interpretation of the configurations of the hydrogenated phosphonates has also been made.
Synthetic, Structural, and Theoretical Investigations of Alkali Metal Germanium Hydrides—Contact Molecules and Separated Ions
Authors: Teng Weijie , Allis Damian G. , Ruhlandt‐Senge Karin
Published: November 2006

The preparation of a series of crown ether ligated alkali metal (M=K, Rb, Cs) germyl derivatives M(crown ether)nGeH3 through the hydrolysis of the respective tris(trimethylsilyl)germanides is reported. Depending on the alkali metal and the crown ether diameter, the hydrides display either contact molecules or separated ions in the solid state, providing a unique structural insight into the geometry of the obscure GeH3− ion. Germyl derivatives displaying MGe bonds in the solid state are of the general formula [M([18]crown‐6)(thf)GeH3] with M=K (1) and M=Rb (4). The compounds display an unexpected geometry with two of the GeH3 hydrogen atoms closely approaching the metal center, resulting in a partially inverted structure. Interestingly, the lone pair at germanium is not pointed towards the alkali metal, rather two of the three hydrides are approaching the alkali metal center to display MH interactions. Separated ions display alkali metal cations bound to two crown ethers in a sandwich‐type arrangement and non‐coordinated GeH3− ions to afford complexes of the type [M(crown ether)2][GeH3] with M=K, crown ether=[15]crown‐5 (2); M=K, crown ether=[12]crown‐4 (3); and M=Cs, crown ether=[18]crown‐6 (5). The highly reactive germyl derivatives were characterized by using X‐ray crystallography, 1H and 13C NMR, and IR spectroscopy. Density functional theory (DFT) and second‐order Møller–Plesset perturbation theory (MP2) calculations were performed to analyze the geometry of the GeH3− ion in the contact molecules 1 and 4.
Coordination Chemistry of a Kinetically Stabilized Germabenzene: Syntheses and Properties of Stable η6‐Germabenzene Complexes Coordinated to Transition Metals
Authors: Tokitoh Norihiro , Nakata Norio , Shinohara Akihiro , Takeda Nobuhiro , Sasamori Takahiro
Published: November 2006

The first stable η6‐germabenzene complexes, that is, [M(CO)3(η6‐C5H5GeTbt)] {M = Cr (2), Mo (3), and W (4); Tbt = 2,4,6‐tris[bis(trimethylsilyl)methyl]phenyl}, have been synthesized by ligand‐exchange reactions between [M(CO)3(CH3CN)3] (M = Cr, Mo, and W) and the kinetically stabilized germabenzene 1 and characterized by 1H and 13C NMR, IR, and UV/Vis spectroscopy. In the 1H and 13C NMR spectra of 2–4, all of the signals for the germabenzene rings were shifted upfield relative to their counterparts in the free germabenzene 1. X‐ray crystallographic analysis of 2 and 4 revealed that the germabenzene ligand was nearly planar and was coordinated to the M(CO)3 group (M = Cr, W) in an η6 fashion. The formation of complexes 2–4 from germabenzene 1 should be noted as the application of germaaromatics as 6π‐electron ligands toward complexation with Group 6 metals. On the other hand, treatment of 1 with [{RuCp*Cl}4] (Cp* = C5Me5) in THF afforded a novel η5‐germacyclohexadienido complex of ruthenium—[RuCp*{η5‐C5H5GeTbt(Cl)}] (9)—instead of the expected η6‐germabenzene‐ruthenium cationic complex [RuCp*{η6‐C5H5GeTbt}]Cl (10). Crystallographic structural analysis of 9 showed that the five carbon atoms of the germacyclohexadienido ligand of 9 were coordinated to the Ru center in an η5 fashion.
Synthesis and Antigenic Analysis of the BclA Glycoprotein Oligosaccharide from the Bacillus anthracis Exosporium
Authors: Mehta Alok S. , Saile Elke , Zhong Wei , Buskas Therese , Carlson Russell , Kannenberg Elmar , Reed Yvonne , Quinn Conrad P. , Boons Geert‐Jan
Published: November 2006

The glycoprotein BclA is an important constituent of the exosporium of Bacillus anthracis spores. This glycoprotein is substituted with an oligosaccharide composed of a β‐L‐rhamnoside substituted with the previously unknown terminal saccharide, 2‐O‐methyl‐4‐(3‐hydroxy‐3‐methylbutanamido)‐4,6‐dideoxy‐D‐glucopyranose, also referred to as anthrose. Anthrose has not been found in spores of B. cereus and B. thuringiensis, making it a potential species‐specific marker for B. anthracis. In order to study the antigenicity of anthrose, efficient syntheses of an anthrose‐containing trisaccharide and a series of structurally related analogues were developed. The analogues lacked either the methyl ether at C‐2 or contained modified C‐4 amino functionalities of anthrose. The synthetic compounds were equipped with an aminopropyl spacer to facilitate conjugation to the carrier proteins mariculture Keyhole Limpet Hemocyanin (mcKLH) and bovine serum albumin (BSA). Serum antibodies of rabbits immunized with live or irradiated spores of B. anthracis Sterne 34F2 were able to recognize the synthetic trisaccharide–mcKLH conjugate. The specificity of the interaction was confirmed by competitive inhibition with the free‐ and BSA‐conjugated trisaccharides. Inhibition using the trisaccharide analogues demonstrated that the isovaleric acid moiety of anthrose is an important structural motif for antibody recognition. These data demonstrate that 1) anthrose is a specific antigenic determinant of the B. anthracis Sterne spore; 2) this antigen is presented to the immune system of rabbits receiving the anthrax live‐spore vaccine; 3) synthetic analogues of the oligosaccharide retain the antigenic structure; and 4) the antigenic region is localized to specific terminal groups of the oligosaccharide. Collectively these data provide an important proof‐of‐concept step in the synthesis and development of spore‐specific reagents for detection and targeting of non‐protein structures in B. anthracis.
Cover Picture: Structure‐Based Organic Synthesis of Drug Prototypes: A Personal Odyssey (ChemMedChem 12/2006)
Authors: Hanessian Stephen
Published: November 2006

The cover picture shows the cyanobacterial linear peptides dysinosin A (RH) and chlorodysinosin A (RCl), members of the aeruginosin family of cyanobacterial linear peptides. Their structures and absolute configurations were determined by total synthesis and X‐ray co‐crystallization with the enzyme thrombin. The presence of one chlorine atom in the D‐leucine residue of chlorodysinosin A remarkably increases the inhibition potency against thrombin and Factor VIIa relative to dysinosin A. Molecular mechanics simulations starting from the bound conformations of dysinosin A and its chloro analogue suggest a more restricted sampling of conformations for the latter around the χ1 dihedral angle. The chlorine atom in chlorodysinosin A may also contribute to lipophilicity, leading to a better fit in the hydrophobic S3 pocket, as illustrated in the partial X‐ray co‐crystal structure. The background of the picture shows Lizard Island in North Queensland, Australia, where dysinosin A was isolated from the Dysideidae family of marine sponges. For details, see the Review by S. Hanessian on p. 1300 ff.
Modified CMOS boot‐strapped inductor
Authors: Scandurra G. , Ciofi C. , Neri B. , Zito D.
Published: November 2006

The boot‐strapped inductor technique has been shown to be a very effective solution to obtain high Q integrated inductors in bipolar technologies. In this paper, starting from a detailed analysis of this technique when applied to a CMOS technology, we propose a new topology that simplifies the design of active inductors even at frequencies quite close to the transition frequency of the active device. As an example, the design and the performances of an active inductor circuit based on a 0.35 µm CMOS technology is also discussed. The device operates at 2.4 GHz of central frequency, presents at its terminals an equivalent inductance of 6 nH and a Q value as high as 400 at the central frequency, with a bias current of less than 1 mA for a voltage supply of 3.3 V. Copyright © 2006 John Wiley & Sons, Ltd.
Speed‐up and performance evaluation of piecewise‐linear DC analysis
Authors: Roos Janne
Published: November 2006

The good convergence properties of piecewise‐linear (PWL) DC analysis have been thoroughly discussed in many papers. This paper, in turn, concentrates on the speed of PWL DC analysis, where the boundary crossing of linear regions plays a crucial role. Fast methods are presented for performing the following boundary‐crossing computations: LU‐decomposition update, matrix‐equation solution, boundary‐crossing direction, and damping‐factor determination. Special attention is given to those PWL DC analysis methods that perform PWL modelling of the non‐linear components on the fly; an adaptive method is proposed for controlling the accuracy of PWL modelling and speeding up simulation. The computational efficiency of the accelerated PWL DC analysis is discussed and compared with that of conventional, Newton–Raphson iteration‐based, DC analysis. Finally, the performance evaluation is completed with realistic simulation examples: it is demonstrated that the speed of the accelerated PWL DC analysis is comparable with that of the conventional DC analysis. Copyright © 2006 John Wiley & Sons, Ltd.
Towards Polymer Diagnostic Agents ― Copolymers of N‐(2‐Hydroxypropyl)methacrylamide and Bis(2‐pyridylmethyl)‐4‐vinylbenzylamine: Synthesis, Characterisation and Re(CO)3‐Labelling
Authors: Kunz Peter C. , Brückmann Nadine E. , Spingler Bernhard
Published: November 2006

Diagnosis of early stage angiogenic tumours is fundamental for cancer therapy. In this study we present the synthesis and characterisation of functionalised HPMA‐copolymers with optimal molecular weights that meet the demands of the enhanced permeability and retention (EPR) effect. Rhenium tricarbonyl complexes of the tripodal ligands bis(2‐pyridylmethyl)benzylamine (1a) and bis(2‐pyridylmethyl)‐4‐vinylbenzylamine (1b) were prepared and characterised by 1H NMR and IR spectroscopy, mass spectrometry and X‐ray diffraction. Ligand 1b was copolymerised with N‐(2‐hydroxypropyl)methacrylamide (HPMA), and the resulting copolymer was treated with (nBu4N)2[Re(CO)3Br3] to yield a Re(CO)3‐labelled copolymer.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Formation of a Dative Bond Between Pt0 and MoII in Linear Pt0–MoII–MoII–Pt0 Complexes, MoII2Pt02(pyphos)4(PR3)2, and Unique 1,4‐Oxidative Addition Reaction of Diaryl Disulfides Giving MoII2PtI2(pyphos)4(SAr)2 (pyphos = 6‐Diphenylphosphanyl‐2‐pyridonato)
Authors: Mashima Kazushi , Shimoyama Yuuji , Kusumi Yoshitaka , Fukumoto Atsushi , Yamagata Tsuneaki , Ohashi Masato
Published: November 2006

The Pt0···MoII dative bond of linear tetrametal Pt0–MoII–MoII–Pt0 complexes, Mo2Pt2(pyphos)4(L)2 [4a: L = PPh3; 4b: L = PMe3; 4c: L = PMe2Ph; 4d: L = PMePh2; 4e: L = P(OMe)3], was characterized by means of spectroscopic analysis and X‐ray crystallographic studies. Complex 4a reacted with diaryl disulfides to give dithiolate PtI complexes, Mo2Pt2(SAr)2(pyphos)4 [5a: Ar = C6H4Me‐4; 5b: C6H4OMe‐4; 5c: C6H3Me2‐2,6; 5d: C6H5], which are unique 1,4‐oxidative addition products.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Polyazaacenes – On the Way to Stable, Fluorescent and Redox‐Active Derivatives
Authors: Stöckner Frances , Beckert Rainer , Gleich Dieter , Birckner Eckhard , Günther Wolfgang , Görls Helmar , Vaughan Gavin
Published: November 2006

A new synthetic method for the preparation of polyazaacenes is described starting from two different nucleophilic building blocks. Disubstituted oxalic amidines 1 can be cyclized under mild conditions with 2,3‐dichloro‐5,6‐dicyanopyrazine (3) to yield 5,6‐dihydropyrazino[2,3‐b]pyrazines 4a–c. By employing higher temperatures and 2 equiv. of 3, octaazanaphthacene 6 can be isolated. Similarly, pyrazino[2,3‐b]pyrazines 2 and bielectrophile 3 yielded novel dodecaazahexacenes 8 in addition to semicyclized derivative 9. When tetraazafulvalene 10d was heated in the presence of an amine in xylene in the presence of oxygen, octaazahexacene 13 was isolated as the main product. Instead of pyrazino[2,3‐b]pyrazines 2, this highly fluorescent polyazaacene was formed from a cascade reaction which involves a dyotropic rearrangement, an intramolecular Diels–Alder reaction and a multistep redox reaction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Direct C–C Coupling of Ferrocenyllithium and Azaheterocycles by Nucleophilic Substitution of Hydrogen – Synthesis of Mono‐ and 1,1′‐Diazinylferrocenes
Authors: Chupakhin Oleg N. , Utepova Irina A. , Kovalev Igor S. , Rusinov Vladimir L. , Starikova Zoya A.
Published: November 2006

A versatile synthetic protocol was proposed for the direct C–C coupling of a ferrocene fragment with various azaheterocycles in the absence of metal catalysts on the basis of nucleophilic substitution of hydrogen. Monosubstituted and disubstituted heteroannular azinyl derivatives of ferrocene were prepared in good yields. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Exploring the evaluation of net charge, hydrodynamic size and shape of peptides through experimental electrophoretic mobilities obtained from CZE
Authors: Piaggio Maria V. , Peirotti Marta B. , Deiber Julio A.
Published: November 2006

This work explores the validity of simple CZE models to analyze the electrophoretic mobilities of 102 peptides reported in literature. These models are based mainly on fundamental physicochemical theories providing analytical expressions amenable to relatively simple numerical analysis. Thus, the Linderstrøm–Lang capillary electrophoresis model (LLCEM) and its perturbed version (PLLCEM), proposed and applied previously to the CZE of globular proteins, are adapted and used here for peptides. Also the effects of pK‐shifts on net charge, hydration and hydrodynamic size and shape of peptides are analyzed and discussed. Emphasis is placed on the fact that these parameters are physically coupled, and thus a variation in the net charge may produce an appreciable change in the hydrodynamic size of peptides. Within the framework of CZE, peptides may be assumed as having a hydrodynamic volume associated with either spherical or spheroidal particles. The effects on peptide net charge and hydrodynamic size, of electrostatic interaction between a pair of charged groups in the chain and electrical permitivitty around the peptide domain are studied. The predictions of the PLLCEM and LLCEM are in good agreement with results reported previously in the literature. Several limitations concerning these models and some needs for further research are also described.
Combining stir bar sorptive extraction and MEKC for the determination of polynuclear aromatic hydrocarbons in environmental and biological matrices
Authors: do Rosário Pedro M. Á. , Nogueira José M. F.
Published: November 2006

In this work, stir bar sorptive extraction and liquid desorption was combined with MEKC and diode‐array detection (SBSE‐LD‐MEKC‐DAD) for the determination of polynuclear aromatic hydrocarbons (PAHs) in aqueous medium, using biphenyl, fluorene, anthracene, phenanthrene, fluoranthene and pyrene as model compounds. MEKC‐DAD conditions and parameters affecting SBSE‐LD efficiency are fully discussed. Assays performed on aqueous samples spiked at trace levels, yielded recoveries ranging from 55.5 ± 6.1% (pyrene) to 70.7 ± 7.1% (anthracene), under optimized experimental conditions. The methodology proved to be nearly described by the octanol‐water partition coefficients (KPDMS/W≈︁KO/W). The analytical performance showed good precision (<12.0%), suitable detection limits (2–11 µg/L) and convenient linear dynamic ranges (r2>0.99) from 5 to 25 µg/L for anthracene and 25 to 125 µg/L for the remaining compounds. The application of the proposed methodology to environmental water, sediments and fish bile matrices demonstrated good selectivity and accuracy. SBSE‐LD combined with MEKC‐DAD was shown to be an easy, reliable and robustness methodology, as well as a good analytical alternative to monitor environmental priority pollutants.
Recent progress in polar stationary phases for CEC
Authors: Ou Junjie , Dong Jing , Dong Xiaoli , Yu Zhiyuan , Ye Mingliang , Zou Hanfa
Published: November 2006

This review summarizes most of the recent developments in the preparation and application of polar stationary phases for CEC covering the literature published since the year 2004. These polar stationary phases have been adopted for separation of analytes by the modes of packing column CEC, open‐tubular CEC (o‐CEC) and monolithic column CEC. Currently, development of o‐CEC using biomolecules, such as protein and DNA, as the immobilized ligands is highlighted partly due to the simplicity of preparation. Furthermore, monolithic columns have been extended quickly, particularly inorganic materials‐based monoliths, such as silica, zirconia, hafnium, etc., as an alternative to packed columns have been developed quickly.
Determination of trace cationic impurities in butylmethylimidazolium‐based ionic liquids: From transient to comprehensive single‐capillary counterflow isotachophoresis‐zone electrophoresis
Authors: Urbánek Marek , Varenne Anne , Gebauer Petr , Křivánková Ludmila , Gareil Pierre
Published: November 2006

Determination of impurities in ionic liquids (ILs) remains a difficult task. In this work, the hyphenation of isotachophoretic (ITP) preconcentration to zone electrophoresis (ZE) has been explored for the trace analysis of the cationic impurities Na+, Li+, and methylimidazolium (MI+) in butylmethylimidazolium (BMI+)‐based ILs. Simultaneous detection of UV‐transparent and UV‐absorbing impurities was ensured by a BGE composed of creatinine‐acetate buffer. To induce ITP, three different strategies were evaluated: (i) Sample self‐stacking ensured by the addition of ammonium acetate (NH4Ac) to 25–50‐fold diluted IL solution (transient ITP). (ii) Complete ITP‐ZE separation performed in a single capillary: ITP was realized in discontinuous electrolytes comprising an 80 mM NH4Ac, 40 mM acetic acid, 30 mM α‐CD, pH 5.05, leading electrolyte (LE) and a 10 mM creatinine, 10 mM acetic acid, pH 4.9, terminating electrolyte (TE). To create the ZE stage, the ITP stack of analytes was moved back toward the capillary inlet by pressure and simultaneously the capillary was filled with the BGE. This protocol made it possible to accommodate a 2.5‐times diluted IL sample. (iii) Complete counterflow ITP‐ZE with continuous electrokinetic sample supply: the ITP stage was performed in a capillary filled with a 150 mM NH4Ac, 75 mM acetic acid, 30 mM α‐CD, pH 5.0 LE, with 40‐times diluted IL at the capillary inlet. BMI+ from IL acts as the terminating ion. The LODs reached in this latter case were at the 10 and 1 ppb levels for MI+ and Li+ in diluted IL matrix, respectively.
Mass distribution, polydispersity and focusing properties of carrier ampholytes for IEF II: pH 4–6 intervals
Authors: Simó Carolina , Mendieta Martha Elena , Antonioli Paolo , Sebastiano Roberto , Citterio Attilio , Cifuentes Alejandro , Peltre Gabriel , Righetti Pier Giorgio
Published: November 2006

For studying theMrdistribution and number of species in narrow‐range (2 pH‐unit wide, in the nominal pI4–6 interval) carrier ampholytes from four commercial sources (Bio‐Lyte, Servalyt, Ampholine and Pharmalyte), a 2‐D technique was adopted consisting of a focusing step in a liquid phase (Rotofor, yielding 20 fractions) followed by orthogonal CE in both, acidic and basic buffers. As a final step, every other fraction was analyzed by CE‐MS. The findings: Ampholine contains 80 differentMrcompounds, in theMrinterval 203 to 893 Da, for a total of 325 isoforms. Bio‐Lyte consists of 66 differentMrspecies, in theMrrange 388 to 835 Da, for a total of 436 isoforms. Servalyt is made of 199 differentMrcompounds, in theMrinterval 204 to 907 Da, for a total of 1302 isoforms. Pharmalyte pH 4–6.5, comprises 217 amphoteres, in theMrrange 150 to 1179 Da, for a total of 812 isoforms. Pharmalyte appears to be the best brand, with the vast majority of species focusing sharply at their pIposition and <5% “poor” species, distributed along the entire pH gradient, denoting an extremely shallow pH/mobility curve across the pIvalue.
Recent progress in capillary ITP
Authors: Gebauer Petr , Malá Zdena , Boček Petr
Published: November 2006

ITP has been attracting constant attention for many years due to its principal capability to concentrate trace analytes by several orders of magnitude. In the current capillary format, it is able to concentrate trace analytes diluted to several microliters of an original sample into concentrated zones having volumes in the range of picoliters. Due to this reason, ITP holds an important position in many current multistage and multidimensional separation schemes. This article links up previous reviews on the topic and summarizes the progress of analytical capillary ITP since 2002. Almost 100 papers are reviewed that include methodological novelties, instrumental aspects, and analytical applications. Papers using ITP and/or isotachophoretic principles as part of multistage and/or multidimensional separation schemes are also included.
Contemporary sample stacking in CE: A sophisticated tool based on simple principles
Authors: Malá Zdena , Křivánková Ludmila , Gebauer Petr , Boček Petr
Published: November 2006

Sample stacking is a general term for methods in CE which are used for on‐line concentration of diluted analytes. During the stacking process, analytes present at low concentrations in a long injected sample zone are concentrated into a short zone (stack). The stacked analytes are then separated and individual zones are detected. Thus stacking provides better separation efficiency and detection sensitivity. Many papers have been published on stacking till now, various procedures have been described, and, many names have been proposed for stacking procedures utilizing the same principles. This contribution brings an easy and unified view on stacking, describes the basic principles utilized, makes a list of recognized operational principles and brings an overview of principal current procedures. Further, it surveys selected recent practical applications ordered according to their operational principles and includes the terms, nicknames, and acronyms used for these actual stacking procedures. This contribution may help both newcomers and experts in the field of CE to orient themselves in the already quite complex topic of sample stacking.
Advances in chiral separation using capillary electromigration techniques
Authors: Gübitz Gerald , Schmid Martin G.
Published: November 2006

This review gives an overview of recent develoments in CZE, EKC, and CEC covering the literature since the year 2004. Since there appeared a special issue on applications, this review focuses on the progress in electromigration techniques and new methodological developments. New techniques, new chiral selectors as well as new chiral stationary phases for CEC are discussed.
Recent progress in the use of ionic polymers as pseudostationary phases for EKC
Authors: Palmer Christopher P.
Published: November 2006

This review concerns the introduction, characterization, and application of polymeric pseudostationary phases (PSPs) for EKC since 2004. Achiral and chiral polymers and separations are reviewed, as is the application of polymeric PSPs for the combination of EKC with mass spectrometric detection.
Recent advances in the development and application of microemulsion EKC
Authors: McEvoy Eamon , Marsh Alex , Altria Kevin , Donegan Sheila , Power Joe
Published: November 2006

Microemulsion EKC (MEEKC) is an electrodriven separation technique. Separations are typically achieved using oil‐in‐water microemulsions, which are composed of nanometre‐sized oil droplets suspended in an aqueous buffer. The droplets are stabilised by a surfactant and a cosurfactant. The novel use of water‐in‐oil microemulsions has also been investigated. This review summarises the advances in the development of MEEKC separations and also the different areas of application including determination of log P values, pharmaceutical applications, chiral analysis, natural products and bioanalytical separations and the use of new methods such as multiplexed MEEKC and high speed MEEKC. Recent applications (2004–2006) are tabulated for each area with microemulsion composition details.
Three cases illustrating the potential of dental treatment as a precipitant for weight loss leading to anorexia nervosa
Authors: Jaffa Tony
Published: November 2006

Objective

This is the first published report to illustrate the potential for dental treatment to precipitate weight loss leading to anorexia nervosa.

Method

Documentation of history and clinical findings on three adolescents referred to a specialist eating disorder service are presented.

Results

These cases illustrate that dental treatment may be precipitants of weight loss leading to anorexia nervosa.

Conclusion

There is a need for increased awareness of this area amongst parents of children and adolescents vulnerable to eating disorders and also their dentists. Copyright © 2006 John Wiley & Sons, Ltd and Eating Disorders Association.
Eating problems and personality traits. An Italian pilot study among 992 high school students
Authors: Abbate‐Daga Giovanni , Gramaglia Carla , Malfi Giuseppe , Pierò Andrea , Fassino Secondo
Published: November 2006

Objective

To evaluate the prevalence of eating problems and to investigate personality traits associated with disturbed eating behaviours among Italian high school students.

Method

Cross‐sectional study involving 992 students from six high schools in Turin, Italy. Students completed the Eating Attitudes Test‐40 (EAT‐40), the Temperament and Character Inventory (TCI) and a Food Frequency Questionnaire (FFQ); their weight and height were measured.

Results

5.5% of the whole sample and 7.4% of girls scored above the EAT‐40 cutoff value. A higher Body Mass Index (BMI) correlates with higher EAT scores. Low scores on Self‐Directedness and Reward Dependence together with high Persistence emerged in subjects with eating problems.

Discussion

Dieting and higher BMI are confirmed as correlates of eating problems. Personality traits measured with the TCI emerge for the first time as correlates of eating problems. Longitudinal studies should clear whether these are risk factors or not. Copyright © 2006 John Wiley & Sons, Ltd and Eating Disorders Association.
Thought suppression in obese and non‐obese restrained eaters: piece of cake or forbidden fruit?
Authors: Soetens Barbara , Braet Caroline , Moens Ellen
Published: November 2006

Objective

This article examines thought suppression tendencies in restrained eaters. Furthermore, the dynamics between failing thought suppression and thought control strategies are explored.

Methods

One hundred and five overweight and normal‐weight boys and girls (12–18 years) participated in a cross‐sectional questionnaire‐based study. A distinction was made between disinhibited restrained eaters (high restraint/high disinhibition), inhibited restrained eaters (high restraint/low disinhibition) and unrestrained eaters (low restraint) in both weight‐groups. The Dutch Eating Behaviour Questionnaire (DEBQ) was used to select the different groups of (un)restrained eaters. The White Bear Suppression Inventory (WBSI) was employed to measure thought suppression and intrusions. The Thought Control Questionnaire (TCQ) was used to measure thought control strategies (distraction, punishment, reappraisal, worry, social control).

Results

The disinhibited restrainers obtained meaningfully higher scores on WBSI‐total, WBSI‐thought suppression and WBSI‐intrusion than the inhibited restrainers and unrestrained eaters in both weight groups. Those who scored high on WBSI‐total, obtained significantly higher scores on the TCQ subscales distraction, worry and punishment, than those who scored low on WBSI‐total.

Discussion

The findings suggest that disinhibited restrainers, irrespective of their weight status, report a high tendency to suppress thoughts. Given Wegner's theoretical account, this may be associated with preoccupations and self‐control difficulties. Copyright © 2006 John Wiley & Sons, Ltd and Eating Disorders Association.
Axon‐glia communication evokes calcium signaling in olfactory ensheathing cells of the developing olfactory bulb
Authors: Rieger Anne , Deitmer Joachim W. , Lohr Christian
Published: November 2006

Olfactory ensheathing cells (OECs) accompany receptor axons in the olfactory nerve and promote axonal growth into the central nervous system. The mechanisms underlying the communication between axons and OECs, however, have not been studied in detail yet. We investigated the effect of activity‐dependent neuronal transmitter release on Ca2+signaling of OECs in acute mouse olfactory bulb slices using confocal Ca2+imaging. TTX‐sensitive axonal activity upon electrical nerve stimulation triggers a rise in cytosolic Ca2+in OECs, which can be mimicked by application of DHPG, an agonist of metabotropic glutamate receptors (mGluRs). Both stimulation‐ and DHPG‐induced Ca2+transients in OECs were abolished by depletion of intracellular Ca2+stores with cyclopiazonic acid (CPA). The mGluR1‐specific antagonist CPCCOEt completely inhibited DHPG‐evoked Ca2+transients, but reduced stimulation‐induced Ca2+transients only partly, suggesting the involvement of another neurotransmitter. Application of ATP evoked CPA‐sensitive Ca2+transients in OECs, which were inhibited by the P2Y1‐specific antagonist MRS2179. Co‐application of CPCCOEt and MRS2179 almost completely blocked the stimulation‐induced Ca2+transients, indicating that they were mediated by mGluR1and P2Y1receptors. Our results show that OECs are able to respond to olfactory nerve activity with an increase in cytosolic Ca2+due to glutamate and ATP release. © 2006 Wiley‐Liss, Inc.
Evidence for synaptic stripping by cortical microglia
Authors: Trapp Bruce D. , Wujek Jerome R. , Criste Gerson A. , Jalabi Walid , Yin Xinghua , Kidd Grahame J. , Stohlman Stephen , Ransohoff Richard
Published: November 2006

Recent studies have described significant demyelination and microglial activation in the cerebral cortex of brains from multiple sclerosis patients. To date, however, experimental models of cortical demyelination or cortical inflammation have not been extensively studied. In this report we describe focal cortical inflammation induced by stereotaxic injection of killed bacteria (BCG), followed 1 month later by subcutaneous injection of the same antigen, a protocol that overcomes the immune privilege of the cortex. Intracerebral BCG injection produced focal microglial activation at the injection site (termed acute lesion). Ten days after peripheral challenge (termed immune‐mediated lesion), larger areas and higher densities of activated microglia were found near the injection site. In both paradigms, activated microglia and/or their processes closely apposed neuronal perikarya and apical dendrites. In the immune‐mediated lesions, ∼45% of the axosomatic synapses was displaced by activated microglia. Upon activation, therefore, cortical microglial migrate to and strip synapses from neuronal perikarya. Since neuronal pathology was not a feature of either the acute or immune‐mediated lesion, synaptic stripping by activated microglia may have neuroprotective consequences. © 2006 Wiley‐Liss, Inc.
Trends in suicide rates of the elderly in Austria, 1970–2004: an analysis of changes in terms of age groups, suicide methods and gender
Authors: Kapusta Nestor D. , Etzersdorfer Elmar , Sonneck Gernot
Published: November 2006

Background

Suicides of the elderly (persons aged 65 and older) make up a large proportion of total suicides. Since suicide rates of the elderly are highest in western populations, addressing them as a risk group in prevention plans has been recommended. In order to assess possible approaches to prevention strategies, this study examines high‐risk groups of the elderly.

Methods

We examined official statistics on suicides that occurred in Austria between 1970–2004 (18,101 Suicides of the elderly). We analyzed time trends and differences in suicide methods as well as in age groups and both genders of the elderly.

Results

Three major high‐risk groups were identified: elderly male suicides by firearms; elderly female suicides by poisoning, which occur more often with increasing age; and suicides of both genders by jumping from heights.

Conclusion

Besides conducting treatment of psychiatric disorders of the elderly, restricting the means to commit suicide may help to prevent it among the elderly. Such specific prevention strategies should be implemented in national suicide prevention plans for the high‐risk groups identified in this study. Copyright © 2006 John Wiley & Sons, Ltd.