bluuebunny/crossref_metadata_2025 huggingface dataset:
Catalytic Asymmetric Addition of Terminal Alkynes to Aldehydes Mediated by (1R,2R)‐2‐(Dimethylamino)‐ 1,2‐diphenylethanol
Authors: Yamashita Mitsuaki , Yamada Ken‐ichi , Tomioka Kiyoshi
Published: October 2005

Catalytic asymmetric alkynylation of aldehydes with terminal alkynes was catalyzed by zinc triflate and (1R,2R)‐2‐(dimethylamino)‐1,2‐diphenylethanol in toluene to give the corresponding alcohols with high enantiomeric excess up to 98% in good yields.
Guanidine‐Catalyzed Asymmetric Trimethylsilylcyanation of Carbonyl Compounds
Authors: Kitani Yukari , Kumamoto Takuya , Isobe Toshio , Fukuda Keiko , Ishikawa Tsutomu
Published: October 2005

Several kinds of modified guanidines were applied to the trimethylsilylcyanation of 3‐phenylpropanal, cylohexanecarboxaldehyde, pivalaldehyde, and 4‐phenyl‐2‐butanone. Good to moderate enantioselectivity was obtained, even on a ketonic substrate, when a C2‐symmetrical bicyclic guanidine, (2S,3S,7S,8S)‐tetraphenyl‐1,4,8‐triaza[2.2.0]bicyclooct‐4‐ene, was used as a base catalyst.
Stereoselective Construction of Quaternary Stereocenters
Authors: Christoffers Jens , Baro Angelika
Published: October 2005

Quaternary stereocenters are a particular challenge for stereoselective synthesis. With a central view on this specific structural issue, selected examples from the recent literature are highlighted in order to evaluate the state of the art of asymmetric CC bond formation. The review is divided into sections on addition and substitution reactions, rearrangements and cycloaddition reactions.
Synthesis of N‐Aryl‐2‐allylpyrrolidines via Palladium‐Catalyzed Carboamination Reactions of γ‐(N‐Arylamino)alkenes with Vinyl Bromides
Authors: Ney Joshua E. , Hay Michael B. , Yang Qifei , Wolfe John P.
Published: October 2005

A palladium‐catalyzed carboamination reaction of γ‐N‐arylamino alkenes with vinyl bromides that affords N‐aryl‐2‐allyl pyrrolidines is described. These reactions proceed with high diastereoselectivity for the formation of trans‐2,3‐ and cis‐2,5‐disubstituted pyrrolidines. Conditions for a tandem N‐arylation/carboamination sequence that leads to the formation of an N‐aryl‐2‐allyl pyrrolidine or indoline via the coupling of a primary γ‐amino alkene, an aryl bromide, and a vinyl bromide are also reported. The mechanism of the carboamination reactions and the origin of unexpected products that formally derive from rearrangement of the vinyl bromide are discussed.
Asymmetric Catalysis of Intramolecular Cyclopropanation of 5‐Aryl‐1‐diazo‐1‐mesitylsulfonyl‐5‐hexen‐2‐ones
Authors: Sawada Takashi , Nakada Masahisa
Published: October 2005

We have examined the catalytic asymmetric intramolecular cyclopropanation (IMCP) reactions of 5‐aryl‐1‐diazo‐1‐mesitylsulfonyl‐5‐hexen‐2‐ones, and found that the substituent of the 5‐aryl group dramatically changes the enantioselectivity. That is, no enantioselectivity was observed when the substituent was a methoxy group; however, enantioselectivity was moderate when the substituent was a methylenedioxy group or a tert‐butyldimethylsilyloxy group, and it dramatically increased when the substituent was lacking (96% ee) or a benzoyloxy group (93% ee).
Bidentate Ligands by Self‐Assembly through Hydrogen Bonding: A General Room Temperature/Ambient Pressure Regioselective Hydroformylation of Terminal Alkenes
Authors: Seiche Wolfgang , Schuschkowski Alexander , Breit Bernhard
Published: October 2005

The 6‐DPPon (1)/rhodium catalyst allows for the first time a room temperature/ambient pressure regioselective hydroformylation of terminal alkenes with low catalyst loadings in good activity. The generality of this catalyst under these conditions was demonstrated for a wide range of structurally diverse alkenes equipped with many important functional groups. Thus, this practical and highly selective hydroformylation protocol, which omits the need for special pressure equipment, should find wide application in organic synthesis.
Asymmetric Catalytic Reductive Coupling of 1,3‐Enynes and Aromatic Aldehydes
Authors: Miller Karen M. , Colby Elizabeth A. , Woodin Katrina S. , Jamison Timothy F.
Published: October 2005

Nickel‐catalyzed reductive coupling reactions of 1,3‐enynes and aromatic aldehydes efficiently afford conjugated dienols in excellent regioselectivity and modest enantioselectivity when conducted in the presence of catalytic amounts of a monodentate, P‐chiral ferrocenyl phosphine ligand. 1‐(Trimethylsilyl)‐substituted enynes are shown to be effective coupling partners in these reactions, and the dienol products thus formed readily undergo protiodesilylation under mild conditions.
Cationic Nickel Complexes with Weakly Coordinating Counterions and Their Application in the Asymmetric Cycloisomerisation of 1,6‐Dienes
Authors: Böing Christian , Franciò Giancarlo , Leitner Walter
Published: October 2005

The influence of the counterion on cationic nickel catalysts for asymmetric cycloisomerisation of diethyl diallylmalonate (1a) and N,N‐diallyltosylamide (1b) is investigated. The activity of the catalysts formed from [Ni(η3‐allyl)(η4‐cod)]+ salts of weakly coordinating anions in combination with Wilke's azaphospholene ligand decreases in the order [Al{OC(CF3)3}4]−>[B{3,5‐(CF3)2‐C6H3}4]−>[Al{OC(CF3)2Ph}4]− for 1a and [B{3,5‐(CF3)2‐C6H3}4]−> [Al{OC(CF3)2Ph}4]−>[Al{OC(CF3)3}4]− for 1b, respectively. No significant influence on the enantioselectivity is observed for 1a whereas a marked increase in ee parallel to a decreasing activity is found for the cyclisation of 1b.
The Direct, Enantioselective, One‐Pot, Three‐Component, Cross‐Mannich Reaction of Aldehydes: The Reason for the Higher Reactivity of Aldimine versus Aldehyde in Proline‐Mediated Mannich and Aldol Reactions
Authors: Hayashi Yujiro , Urushima Tatsuya , Shoji Mitsuru , Uchimaru Tadafumi , Shiina Isamu
Published: October 2005

In the proline‐mediated Mannich and aldol reactions of propanal as a nucleophile, the aldimine prepared from benzaldehyde and p‐anisidine is about 7 times more reactive than the corresponding aldehyde, benzaldehyde, as an electrophile. This higher reactivity of aldimine over aldehyde is attributed to the carboxylic acid of proline protonating the basic nitrogen atom of the aldimine more effectively than the oxygen atom of the aldehyde, an explanation which has been both experimentally and theoretically verified.
Highly Enantio‐ and Diastereoselective Construction of 1,2‐Disubstituted Cyclopentane Compounds by Dirhodium(II) Tetrakis[N‐phthaloyl‐(S)‐tert‐leucinate]‐Catalyzed CH Insertion Reactions of α‐Diazo Esters
Authors: Minami Kazushi , Saito Hiroaki , Tsutsui Hideyuki , Nambu Hisanori , Anada Masahiro , Hashimoto Shunichi
Published: October 2005

A highly enantio‐ and diastereoselective intramolecular CH insertion reaction of α‐diazo esters has been achieved with the use of dirhodium(II) tetrakis[N‐phthaloyl‐(S)‐tert‐leucinate] as a catalyst, providing exclusively cis‐2‐arylcyclopentane‐1‐carboxylates in up to 95% ee with no evidence of alkene formation.
Thiophenol‐Mediated 1,5‐Hydrogen Atom Abstraction: Easy Access to Mono‐ and Bicyclic Compounds
Authors: Beaufils Florent , Dénès Fabrice , Becattini Barbara , Renaud Philippe , Schenk Kurt
Published: October 2005

A thiophenol‐mediated method for cyclization of alkynes is described. The reaction cascade involves the intermolecular addition of a phenylthiyl radical to a terminal triple bond generating an alkenyl radical, followed by a 1,5‐hydrogen atom transfer and a 5‐exo‐trig radical cyclization. This very efficient tin‐free procedure allows one to prepare highly functionalized cyclopentane derivatives as well as fused bicyclic and spirocyclic compounds from easily available precursors. During this cyclization process, a phenylthio moiety is incorporated into the final cyclized products. This functionalization is particularly attractive for further transformation of the products.
Highly Enantioselective Aza‐Baylis–Hillman Reactions Catalyzed by Chiral Thiourea Derivatives
Authors: Raheem Izzat T. , Jacobsen Eric N.
Published: October 2005

We report the discovery of asymmetric aza‐Baylis–Hillman (ABH) reactions of N‐p‐nitrobenzenesulfonylimines with methyl acrylate catalyzed by chiral thiourea derivatives. A series of aromatic imines was found to undergo coupling with methyl acrylate with unprecedented levels of enantioselectivity (87–99% ee), albeit only in modest (25–49%) yields. A DABCO‐acrylate‐imine adduct was isolated as a key intermediate in the ABH reaction. We provide a mechanistic analysis based on the identity of this intermediate as well as kinetic investigations and isotope studies, and propose a rationale for the observed limitations in yield. Synthetic applications of the ABH products are also described.
T‐Cell lymphoblastic lymphoma presenting as bilateral multinodular breast masses: A case report and review of the literature
Authors: Vakiani Efsevia , Savage David G. , Pile‐Spellman Eliza , El‐Tamer Mahmoud , Singh Ila R. , Murty Vundavalli S. , Alobeid Bachir , Bhagat Govind
Published: October 2005

Non‐Hodgkin lymphoma of T‐cell lineage involving the breast is rare. We report on a 41‐year‐old woman with T‐cell lymphoblastic lymphoma who presented with multiple bilateral breast masses. The patient was treated with intensive chemotherapy and mediastinal and whole‐brain irradiation. She remains in complete remission 24 months after diagnosis. The clinical, histologic, phenotypic, and cytogenetic features are described, with a review of the literature. Am. J. Hematol. 80:216–222, 2005. © 2005 Wiley‐Liss, Inc.
Overexpression of cyclooxygenase‐2 in multiple myeloma: Association with reduced survival
Authors: Cetin Mustafa , Buyukberber Suleyman , Demir Muzaffer , Sari Ismail , Sari Ibrahim , Deniz Kemal , Eser Bulent , Altuntas Fevzi , Camcı Celalettin , Öztürk Ahmet , Turgut Burhan , Vural Özden , Unal Ali
Published: October 2005

Cyclooxygenases (COX) are key enzymes in the conversion of arachidonic acid to prostaglandins. Several studies have shown a relation between angiogenesis and COX‐2 expression. Elevated expression of cyclooxygenase‐2 (COX‐2), however, has not been reported in multiple myeloma (MM) in the literature. The aim of this study is to investigate COX‐2 expression in MM as well as its correlation with prognostic factors and estimated survival rates. Immunohistochemical staining of the paraffin‐embedded bone marrow biopsy tissues (n = 51) was performed using isoform‐specific COX‐2 polyclonal antisera (Santa Cruz Biotechnology, Santa Cruz, CA). Results were correlated with recognized clinical parameters, which were retrospectively obtained from patients' files. There were 15, 19, and 17 bone marrow biopsy specimens with negative, weak–moderate, and strong COX‐2 immunostaining, respectively. According to univariate analysis, β2‐microglobulin, age, stage, COX‐2 expression, and serum lactate dehydrogenase levels were significant prognostic factors for survival in patients with multiple myeloma. COX‐2 expression, age, and serum lactate dehydrogenase levels (greater than 1× normal level) were significant prognostic factors by multivariate analysis. Kaplan–Meier overall survival estimate of those patients with negative or weak–moderate COX‐2 immunoreactivity in myeloma cells was significantly better than that of patients with strong COX‐2 immunoreactivity (log‐rank χ2 = 21,43, P < 0.001). COX‐2 overexpression was associated with reduced estimated survival. Poor prognostic factors such as LDH, age, and β2‐microglobulin were also correlated with COX‐2 expression. Potent, specific COX‐2 inhibitors showing evident antiangiogenic and antitumor effects on cancers could provide new therapeutic strategies in the treatment of MM. Am. J. Hematol. 80:169–173, 2005. © 2005 Wiley‐Liss, Inc.
Simple and economical conversion of organic compounds with H2O2 catalyzed by ruthenium (III) chloride
Authors: Tandon Praveen K. , Baboo Ramesh , Singh Alok K. , Gayatri
Published: October 2005

Six aromatic aldehydes, two hydrocarbons, one cycloalcohol and one aromatic alcohol, viz. benzaldehyde, p‐chlorobenzaldehyde, cinnamaldehyde, 4‐methoxybenzaldehyde, o‐hydroxybenzaldehyde, 4‐hydroxy, 3‐methoxybenzaldehyde, anthracene, phenanthrene, cyclohexanol and benzyl alcohol dissolved in acetic acid, were oxidized in quantitative to moderate yields by 50% H2O2 in the presence of traces of RuCl3 (substrate:catalyst ratio 85 400 to 387 500:1). Conditions for highest yields, under most economical conditions, were obtained. Higher catalyst concentrations decreased the yield. Oxidation in aromatic aldehydes is selective at aldehydic group only, and other groups remain unaffected. The extent of oxidation in phenanthrene depends on temperature or the relative amount of substrate or both. In this new, simple and economical method, which is environmentally safe and requires less time, oxocentered carboxylate species of ruthenium (III) probably catalyze the oxidation. Copyright © 2005 John Wiley & Sons, Ltd.
Human information behavior: Integrating diverse approaches and information use
Authors: Spink Amanda , Cole Charles
Published: October 2005

For millennia humans have sought, organized, and used information as they learned and evolved patterns of human information behaviors to resolve their human problems and survive. However, despite the current focus on living in an “information age,” we have a limited evolutionary understanding of human information behavior. In this article the authors examine the current three interdisciplinary approaches to conceptualizing how humans have sought information including (a) the everyday life information seeking–sense‐making approach, (b) the information foraging approach, and (c) the problem–solution perspective on information seeking approach. In addition, due to the lack of clarity regarding the role of information use in information behavior, a fourth information approach is provided based on a theory of information use. The use theory proposed starts from an evolutionary psychology notion that humans are able to adapt to their environment and survive because of our modular cognitive architecture. Finally, the authors begin the process of conceptualizing these diverse approaches, and the various aspects or elements of these approaches, within an integrated model with consideration of information use. An initial integrated model of these different approaches with information use is proposed.
Epicyclic oscillation modes of a Newtonian, non‐slender torus
Authors: Šrámková E.
Published: October 2005

All normal modes of oscillations of slender tori have been expressed analytically in the classic work by Blaes (1985). We adopt his approach in order to calculate the eigenfunctions and eigenfrequencies of a particular class of epicyclic modes for slightly non‐slender tori, and present results of our numerical simulation of torus epicyclic modes of oscillations, which will be compared with the analytical results. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A possible mechanism for QPOs modulation in neutron star sources
Authors: Horák J.
Published: October 2005

It was pointed out by Paczyński (1987) that the X‐ray luminosity of accreting neutron stars is very sensitive to the physical properties of the accretion flow close to the innermost stable circular orbit. The X‐ray radiation is dominated by that emitted in the boundary layer, where accreted matter hits a star surface. The X‐ray luminosity of the boundary layer is proportional to the local accretion rate. In this note, we estimate a local accretion rate variations from the disk that undergoes non‐stationary axisymmetric perturbations. The perturbations are given by the poloidal‐velocity potential.We obtain a simple formula describing the modulation of the accretion rate for the particular case of global vertical disk oscillations that have been recently studied by Abramowicz et al. (2005). (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
QPOs in microquasars and Sgr A.: measuring the black hole spin
Authors: Török G.
Published: October 2005

In all four microquasars which show double peak kHz QPOs, the ratio of the two frequencies is 3:2. This strongly supports the suggestion that twin peak kHz QPOs are due to a resonance between some modes of accretion disk oscillations. Here, we stress that fits to observations of the hypothetical resonances between vertical and radial epicyclic frequencies (particularly of the parametric resonance) give an accurate estimate of the spin for the three microquasars with known mass. Measurement of double peak QPOs frequencies in the Galaxy centre seems also to be consistent with the 3:2 ratio established by previous observations in microquasars, however the SgrA* data are rather difficult for the same exact analysis. If confirmed, the 3:2 ratio of double peak QPOs in SgrA* would be of a fundamental importance for the black hole accretion theory and the precise measurement could help to solve the question of QPOs nature. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
TRIM/RBCC, a novel class of ‘single protein RING finger’ E3 ubiquitin ligases
Authors: Meroni Germana , Diez‐Roux Graciana
Published: October 2005

The TRIM/RBCC proteins are defined by the presence of the tripartite motif composed of a RING domain, one or two B‐box motifs and a coiled‐coil region. These proteins are involved in a plethora of cellular processes such as apoptosis, cell cycle regulation and viral response. Consistently, their alteration results in many diverse pathological conditions. The highly conserved modular structure of these proteins suggests that a common biochemical function may underlie their assorted cellular roles. Here, we review recent data indicating that some TRIM/RBCC proteins are implicated in ubiquitination and propose that this large protein family represents a novel class of ‘single protein RING finger’ ubiquitin E3 ligases. BioEssays 27:1147–1157, 2005. © 2005 Wiley Periodicals, Inc.
Local proteolytic activity in tumor cell invasion and metastasis
Authors: Ludwig Thomas
Published: October 2005

Proteolytic cleavage of extracellular matrix (ECM) is a critical regulator of many physiological and pathological events. It affects fundamental processes such as cell growth, differentiation, apoptosis and migration. Most proteases are produced as inactive proenzymes that undergo proteolytic cleavage for activation. Proteolytic activity is additionally modified by endogenous inhibitors. Mechanisms that localize and concentrate protease activity in the pericellular microenvironment of cells are prerequisites for processes like angiogenesis, bone development, inflammation and tumor cell invasion. Methods that enable real‐time, high‐resolution imaging and precise quantification of local proteolytic activity in vitro and in vivo remain major challenges. These methods will play an important role in the understanding of basic principles e.g. in cancer cell invasion, the identification of new therapeutical targets and hence drug design. This review highlights mechanisms and functions of local proteolytic activity with special emphasis on tumor cell invasion and metastasis, and focuses on techniques for the investigation of this process. BioEssays 27:1181–1191, 2005. © 2005 Wiley Periodicals, Inc.
KASH 'n Karry: The KASH domain family of cargo‐specific cytoskeletal adaptor proteins
Authors: Starr Daniel A. , Fischer Janice A.
Published: October 2005

A diverse family of proteins has been discovered with a small C‐terminal KASH domain in common. KASH domain proteins are localized uniquely to the outer nuclear envelope, enabling their cytoplasmic extensions to tether the nucleus to actin filaments or microtubules. KASH domains are targeted to the outer nuclear envelope by SUN domains of inner nuclear envelope proteins. Several KASH protein genes were discovered as mutant alleles in model organisms with defects in developmentally regulated nuclear positioning. Recently, KASH‐less isoforms have been found that connect the cytoskeleton to organelles other than the nucleus. A widened view of these proteins is now emerging, where KASH proteins and their KASH‐less counterparts are cargo‐specific adaptors that not only link organelles to the cytoskeleton but also regulate developmentally specific organelle movements. BioEssays 27:1136–1146, 2005. © 2005 Wiley Periodicals, Inc.
A twisted hand: bHLH protein phosphorylation and dimerization regulate limb development
Authors: Cai Juanliang , Jabs Ethylin Wang
Published: October 2005

Saethre‐Chotzen syndrome (SCS), a human autosomal dominant condition with limb defects and craniosynostosis, is caused by haploinsufficiency of TWIST1, a basic helix–loop–helix (bHLH) transcription factor. Until recently, the molecular pathogenesis of the limb defects in SCS has not been well understood. Now, Firulli et al.1 show in mouse and chick that ectopic expression of a related bHLH protein, Hand2, results in phenocopies of the limb defects caused by Twist1 loss‐of‐function mutations. These two proteins interact in a dosage‐dependent antagonistic manner, and both can be regulated through phosphorylation at conserved helix I amino acid residues. These findings provide an important link between the misregulation of Twist1 dimerization and the limb phenotypes observed in SCS. BioEssays 27:1102–1106, 2005. © 2005 Wiley Periodicals, Inc.
Transcription factors and DNA replication origin selection
Authors: Kohzaki Hidetsugu , Murakami Yota
Published: October 2005

The chromosomes of eukaryotic cells possess many potential DNA replication origins, of which a subset is selected in response to the cellular environment, such as the developmental stage, to act as active replication start sites. The mechanism of origin selection is not yet fully understood. In this review, we summarize recent observations regarding replication origins and initiator proteins in various organisms. These studies suggest that the DNA‐binding specificities of the initiator proteins that bind to the replication origins and promote DNA replication are primarily responsible for origin selection. We particularly focus on the importance of transcription factors in the origin selection process. We propose that transcription factors are general regulators of the formation of functional complexes on the chromosome, including the replication initiation complex. We discuss the possible mechanisms by which transcription factors influence the selection of particular origins. BioEssays 27:1107–1106, 2005. © 2005 Wiley Periodicals, Inc.
A mathematical model of N‐linked glycosylation
Authors: Krambeck Frederick J. , Betenbaugh Michael J.
Published: October 2005

Metabolic engineering of N‐linked oligosaccharide biosynthesis to produce novel glycoforms or glycoform distributions of a recombinant glycoprotein can potentially lead to an improved therapeutic performance of the glycoprotein product. A mathematical model for the initial stages of this process, up to the first galactosylation of an oligosaccharide, was previously developed by Umana and Bailey (1997) (UB1997). Building on this work, an extended model is developed to include further galactosylation, fucosylation, extension of antennae by N‐acetyllactosamine repeats, and sialylation. This allows many more structural features to be predicted. A number of simplifying assumptions are also relaxed to incorporate more variables for the control of glycoforms. The full model generates 7565 oligosaccharide structures in a network of 22,871 reactions. Methods for solving the model for the complete product distribution and adjusting the parameters to match experimental data are also developed. A basal set of kinetic parameters for the enzyme‐catalyzed reactions acting on free oligosaccharide substrates is obtained from the previous model and existing literature. Enzyme activities are adjusted to match experimental glycoform distributions for Chinese Hamster Ovary (CHO). The model is then used to predict the effect of increasing expression of a target glycoprotein on the product glycoform distribution and evaluate appropriate metabolic engineering strategies to return the glycoform profile to its original distribution pattern. This model may find significant utility in the future to predict glycosylation patterns and direct glycoengineering projects to optimize glycoform distributions. © 2005 Wiley Periodicals, Inc.
Corporate engagement in processes for planetary sustainability: understanding corporate capacity in the non‐renewable resource extractive sector, Australia
Authors: Harris Neil
Published: October 2005

In recent years corporations have come under increasing pressure from governments, consumers, investors, competitors, business partners and communities to balance their pursuit of economic gain with environmental and social concerns. Non‐renewable resource extractive corporations in particular, due to their profile, visibility and activities, have come under mounting pressure to embed the concept of ecological sustainability into strategic decision‐making processes and operations. In this regard, there is a growing base of evidence that describes efforts, successes and failures in the sector to meet mounting societal expectations. However, to date there has been limited explanatory research into corporate capacity to engage in processes for ecological sustainability.

This paper presents an emergent explanation of the internal factors mediating corporate engagement in ecological sustainability in non‐renewable resource extractive corporations in Australia. It identifies the five factors of leadership, resources, structures, culture and understanding and conceptualizes these internal factors as capacity for engagement. While all of the factors are seen as interdependent and essential, leadership is identified as the most critical. Copyright © 2005 John Wiley & Sons, Ltd and ERP Environment.
Measuring TQEM returns from the application of quality frameworks
Authors: Curkovic Sime , Sroufe Robert , Landeros Robert
Published: October 2005

This study addresses one of the major perceived barriers to total quality environmental management (TQEM): cost measurement. Operations managers have difficulty assessing the impact of TQEM programs because of the lack of appropriate measures. In order for TQEM to be given serious consideration, a cost framework is required for evaluating TQEM by appropriately including all the environmental costs and savings for each investment option. At present, frameworks such as life‐cycle assessment (LCA) and environmental cost accounting (ECA) exist, but they have both been recognized as too difficult to implement at the plant level among operations managers. This study focuses on identifying and formulating a set of easy‐to‐use quantitative cost measures. The structure of these measures is taken from the operations management (OM) literature itself, and specifically the total quality management (TQM) and cost of quality (COQ) frameworks developed by Joseph Juran. However, an empirical examination of this remains untested. The findings of this study provide an important foundation for theory development and set the stage for further research in this burgeoning field of TQEM. Copyright © 2005 John Wiley & Sons, Ltd and ERP Environment.
Access of the Substrate to the Active Site of Yeast Oxidosqualene Cyclase: An Inhibition and Site‐Directed Mutagenesis Approach
Authors: Oliaro‐Bosso Simonetta , Schulz‐Gasch Tanja , Balliano Gianni , Viola Franca
Published: October 2005

A structural model of Saccharomyces cerevisiae oxidosqualene cyclase (SceOSC) suggests that some residues of the conserved sequence Pro‐Ala‐Glu‐Val‐Phe‐Gly (residues 524–529) belong to a channel constriction that gives access to the active‐site cavity. Starting from the SceOSC C457D mutant, which lacks the cysteine residue next to the catalytic Asp456 residue Cys457 has been replaced but Asp456 is still there, we prepared two further mutants where the wild‐type residues Ala525 and Glu526 were individually replaced by cysteine. These mutants, especially E526C, were very sensitive to the thiol‐reacting agent dodecyl‐maleimide. Moreover, both the specific activity and the thermal stability of E526C were severely reduced. A similar decrease of the enzyme functionality was obtained by replacing Glu526 with alanine, while substitution with the conservative residues aspartate or glutamine did not alter catalytic activity. Molecular modeling of the yeast wild‐type OSC and mutants on the template structure of human OSC confirms that the channel constriction is an important aspect of the protein structure and suggests a critical structural role for Glu526.
An integrated approach to the characterization of cell movement
Authors: Costa Luciano da Fontoura , Cintra Leandro Carrijo , Schubert David
Published: October 2005

Background

Most phenomena in developmental biology involve or depend upon cell migration. This article describes a comprehensive framework for the characterization and analysis of trajectories defined by cell movement. The following two perspectives are considered: (a) the behavior of each individual cell and (b) interactions between neighboring pairs of cells.

Methods

The measurements considered for individual trajectories include the velocity magnitude and orientation, maximum spatial dispersion, displacement effectiveness, and displacement entropies. Interactions between two trajectories are characterized by comparing the respective velocities.

Results

The potential of the overall framework is illustrated using data of moving cells in different biological environments. The work shows that it is possible to use the new algorithm presented here to characterize cell motility.

Conclusions

The features of the algorithm were successful in determining the motility changes under different experimental conditions. © 2005 Wiley‐Liss, Inc.
FCS cell surface measurements—Photophysical limitations and consequences on molecular ensembles with heterogenic mobilities
Authors: Widengren Jerker , Thyberg Per
Published: October 2005

Background

Fluorescence Correlation Spectroscopy is a powerful method to analyze densities and diffusive behavior of molecules in membranes, but effects of photodegradation can easily be overlooked.

Method

Based on experimental photophysical parameters, calculations were performed to analyze the consequences of photobleaching in fluorescence correlation spectroscopy (FCS) cell surface experiments, covering a range of standard measurement conditions.

Results

Cumulative effects of photobleaching can be prominent, although an absolute majority of the fluorescent molecules would pass the laser excitation beam without being photobleached. Given a distribution of molecules on a cell surface with different diffusive properties, the fraction of molecules that is actually analyzed depends strongly on the excitation intensities and measurement times, as well as on the size of the reservoir of freely diffusing molecules. Both the slower and the faster diffusing molecules can be disfavored.

Conclusions

Apart from quantifying photobleaching effects, the calculations suggest that the effects can be used to extract additional information, for instance about the size of the reservoirs of free diffusion. By certain choices of measurement conditions, it may be possible to more specifically analyze certain species within a population, based on their different diffusive properties, different areas of free diffusion, or different kinetics of possible transient binding. © 2005 Wiley‐Liss, Inc.
Non-parametric estimation of mean customer lifetime value
Authors: Pfeifer Phillip E. , Bang Heejung
Published: October 2005

This paper is about how to use data from a random sample of customer relationships to calculate an appropriate average customer lifetime value (CLV). When the sample contains only completed relationships, the simple unweighted average is appropriate. When the sample contains a mix of active and completed relationships, the lifetimes of the active relationships are said to be right censored because the observed lifetime to date is but a lower bound on the eventual lifetime. Because of this censoring, a simple average of the sample CLVs to date will be a biased estimate of the mean CLV. This paper presents and explores several non-parametric estimation methods for correcting for this bias.
Best face forward: Improving companies’ service interfaces with customers
Authors: Rayport Jeffrey F. , Jaworski Bernard J. , Kyung Ellie J.
Published: October 2005

In the face of increasingly demanding customers and a shortage of skilled workers to serve them, companies are facing a crisis in customer interaction and relationship management. At the same time, networked technologies–from Web sites to kiosks to interactive voice response units–are enabling managers to “recruit” machines into front-office roles that drive down the costs of consumer interactions and deliver satisfying customer experiences. Successfully integrating technology into the work force requires a wholesale reengineering of the front-office to determine the appropriate division of labor between humans and machines. Here we examine the origins of what we call the “front-office revolution” and the need for businesses to manage coordinated interface systems. We suggest that companies do an audit of their interfaces and optimize them over three phases, which we call separate, relate, and integrate phases. We argue that these interface systems, and the more efficient and effect customer relationship management they enable, represent the next frontier of competitive advantage for many businesses.
Expression and functional analysis of genes deregulated in mouse placental overgrowth models: Car2 and Ncam1
Authors: Singh Umashankar , Sun Tong , Shi Wei , Schulz Ralph , Nuber Ulrike A. , Varanou Aikaterini , Hemberger Myriam C. , Elliott Rosemary W. , Ohta Hiroshi , Wakayama Teruhiko , Fundele Reinald
Published: October 2005

Different causes, such as maternal diabetes, cloning by nuclear transfer, interspecific hybridization, and deletion of some genes such as Esx1, Ipl, or Cdkn1c, may underlie placental overgrowth. In a previous study, we carried out comparative gene expression analysis in three models of placental hyperplasias, cloning, interspecies hybridization (IHPD), and Esx1 deletion. This study identified a large number of genes that exhibited differential expression between normal and enlarged placentas; however, it remained unclear how altered expression of any specific gene was related to any specific placental phenotype. In the present study, we focused on two genes, Car2 and Ncam1, which both exhibited increased expression in interspecies and cloned hyperplastic placentas. Apart from a detailed expression analysis of both genes during normal murine placentation, we also assessed morphology of placentas that were null for Car2 or Ncam1. Finally, we attempted to rescue placental hyperplasia in a congenic model of IHPD by decreasing transcript levels of Car2 or Ncam1. In situ analysis showed that both genes are expressed mainly in the spongiotrophoblast, however, expression patterns exhibited significant variability during development. Contrary to expectations, homozygous deletion of either Car2 or Ncam1 did not result in placental phenotypes. However, expression analysis of Car3 and Ncam2, which can take over the function of Car2 and Ncam1, respectively, indicated a possible rescue mechanism, as Car3 and Ncam2 were expressed in spongiotrophoblast of Car2 and Ncam1 mutant placentas. On the other hand, downregulation of either Car2 or Ncam1 did not rescue any of the placental phenotypes of AT24 placentas, a congenic model for interspecies hybrid placentas. This strongly suggested that altered expression of Car2 and Ncam1 is a downstream event in placental hyperplasia. Developmental Dynamics 234:1034–1045, 2005. © 2005 Wiley‐Liss, Inc.
Asymmetric Organocatalysis with Novel Chiral Thiourea Derivatives: Bifunctional Catalysts for the Strecker and Nitro‐Michael Reactions
Authors: Tsogoeva Svetlana B. , Yalalov Denis A. , Hateley Martin J. , Weckbecker Christoph , Huthmacher Klaus
Published: October 2005

Novel bifunctional organocatalysts bearing both a thiourea moiety and an imidazole group on a chiral scaffold were synthesized and applied to the Strecker synthesis and nitro‐Michael reaction. The addition of acetone to nitroolefins in the presence of these novel bifunctional organocatalysts gave enantioselectivities (up to 87 % ee) that are superior to those generated by the proline and/or homo‐proline tetrazole catalysts described in the literature. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
A General Study of Aryloxo and Alkoxo Ligands in the Titanium‐Catalyzed Intermolecular Hydroamination of Terminal Alkynes
Authors: Tillack Annegret , Khedkar Vivek , Jiao Haijun , Beller Matthias
Published: October 2005

A general study of the regioselective hydroamination of terminal alkynes in the presence of Ti(NEt2)4 and different aryloxo and alkoxo ligands is presented. Depending on the ligand the regioselectivity towards the Markovnikov and the anti‐Markovnikov addition product can be controlled. The experimentally observed isomer distribution is explained perfectly by detailed theoretical investigations which demonstrate that the regioselectivity is determined by the relative stability of the corresponding alkynetitanium π complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Cerium‐Catalyzed, Aerobic Oxidative Synthesis of 1,2‐Dioxane Derivatives from Styrene and Their Fragmentation into 1,4‐Dicarbonyl Compounds
Authors: Rössle Michael , Werner Thomas , Frey Wolfgang , Christoffers Jens
Published: October 2005

1,4‐Diketones were prepared by cerium‐catalyzed oxidative coupling of styrene with molecular oxygen and 1,3‐dicarbonyl compounds. This two‐step sequence was performed as a one‐pot procedure without isolation of the intermediate products. The first step is a metal‐catalyzed radical reaction yielding 3‐hydroxy‐1,2‐dioxane derivatives being the cyclotautomers of initially formed 4‐hydroperoxy ketones. In the second step of this sequence, these endoperoxides are converted with AcCl–pyridine by Kornblum–DeLaMare fragmentation into the 1,4‐dicarbonyl motif. Several intermediate 1,2‐dioxane derivatives could be isolated and structurally characterized by X‐ray crystallography. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis of Dihydrofurans Substituted in the 2‐Position
Authors: Kilroy Timothy G. , O'Sullivan Timothy P. , Guiry Patrick J.
Published: October 2005

Many natural products and biologically active compounds contain the dihydrofuran subunit. Molecules incorporating either 2‐substituted, 2,2‐disubstituted 2,3‐ or 2,5‐dihydrofurans are widespread in the literature and represent key “molecular building blocks”. The preparation of substituted dihydrofurans remains a current challenge in organic synthesis and this microreview details the various routes employed for their synthesis in the literature to the end of 2004. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis and Properties of New Nucleotide Analogues Possessing Squaramide Moieties as New Phosphate Isosters
Authors: Seio Kohji , Miyashita Takuhei , Sato Kousuke , Sekine Mitsuo
Published: October 2005

New analogues of 2′‐deoxynucleotides and ribonucleotides incorporating a unique squaramide structure were synthesized. Because of the strong acidity of this moiety (pKa = 2.3), these nucleotide analogues exist in a monoanionic form, which can be regarded as an electronic isoster of 5′‐nucleotides under physiological conditions. The synthesis of the nucleotide analogues was achieved through the condensation of 5′‐ or 3′‐aminonucleosides with dimethyl squarate, whilst the selective removal of the methyl group was effectively accomplished by treatment with sodium bromide. In addition, we also synthesized 3′,5′‐cyclic nucleotide analogues from the 3′,5′‐diazidonucleoside derivatives. NMR analysis revealed that their ribose puckering was of an N‐type form, identical to that in cAMP and cGMP. Because of the unique structural, electronic, and conformational properties of squaramide‐type nucleotide analogues, these analogues should be quite interesting as potential biologically active compounds such as antiviral and anticancer agents. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Spin–Spin Interactions Across the “Cove” in the (Z) and (E) Isomers of 1,1′‐Difluoro‐9,9′‐bifluorenylidene
Authors: Krcsmar Lidia , Grunenberg Jörg , Dix Ina , Jones Peter G. , Ibrom Kerstin , Ernst Ludger
Published: October 2005

In the (Z) isomer, but not in the (E) isomer of title compound 1, moderate 19F,19F spin–spin coupling across the “cove” is observed [J(F,F) = 11.0 Hz], which is deemed to obey a through‐space mechanism. The coupling between the isochronous fluorine nuclei of 1Z causes second‐order effects in the 1H, 13C and 19F NMR spectra of this compound and allows its easy distinction from the (E) isomer. A B3LYP/6‐31+G(d) calculation of 1Z as an isolated molecule was carried out which gave a non‐bonded F,F distance d(F,F) of 2.711 Å and an angle between the two C–F bond vectors of 34.1°. The computed F···F compliance constant of 6.96 Å/mdyn points to a very weak interaction. According to our previous correlation between d(F,F) and through‐space J(F,F), the F,F distance in 1Z would be expected to go along with a coupling constant of ca. 46 Hz. This discrepancy between prediction and experiment gives support to our earlier presumption that a simple d(F,F)/J(F,F) correlation may not sufficiently describe through‐space couplings and that an angular factor should also be taken into account. An X‐ray diffraction study of 1Z resulted in an F,F distance of 2.638 Å and an angle between the C–F bonds of 36.4°, in fair agreement with the MO calculation. The rigidity of the (Z) isomer was studied using theoretical compliance constants. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Bismuth Triflate Catalyzed Mukaiyama Aldol Reaction in an Ionic Liquid
Authors: Ollevier Thierry , Desyroy Valerie , Debailleul Blandine , Vaur Sophie
Published: October 2005

We have developed an efficient, bismuth triflate catalyzed Mukaiyama aldol reaction. The reaction proceeds rapidly and affords the corresponding β‐hydroxy carbonyl compound in moderate to very good yields (up to 92 %). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Electrochemical Evaluation of Nucleoside Analogue Lamivudine in Pharmaceutical Dosage Forms and Human Serum
Authors: Dogan Burcu , Uslu Bengi , Suzen Sibel , Ozkan Sibel A.
Published: October 2005

Lamivudine (LAM) is a synthetic nucleoside analogue with activity against human immunodeficiency virus‐type 1 (HIV‐1) and Hepatitis B virus (HBV). The aim of this study was to determine LAM levels in serum and pharmaceutical formulations, by means of electrochemical methods using hanging mercury drop electrode (HMDE). On this electrode, LAM undergoes irreversible reduction at the peak potential near Ep−1.26 V (vs. Ag/AgCl/3 M KCl). Reduction LAM signals were measured by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and square‐wave voltammetry (OSW). DPV and OSW techniques for the determination of LAM in acetate buffer at pH 4.5, which allows quantitation over the 4×10−6 to 1×10−4 M range in supporting electrolyte for both methods, were proposed. The linear response was obtained in acetate buffer in the ranges of 2×10−6 to 2×10−4 M for spiked serum samples at pH 4.5 for both techniques. The repeatability and reproducibility of the methods for all media were determined. The standard addition method was used in serum. Precision and accuracy were also checked in all media. No electroactive interferences from the endogenous substances were found in serum. With respect to side effects of high doses and short half‐life of LAM, a fast and simple detection method is described in this study.
Highly Thiocyanate‐Selective PVC Membrane Electrode Based on Lipophilic Ferrocene Derivative
Authors: Dai Jianyuan , Yuan Ruo , Chai Yaqin , An Lanxiang , Zhong Xia , Liu Yan , Tang Dianping
Published: October 2005

A novel anion‐selective PVC membrane electrode based on bis‐[(3‐ferrocenyl)‐(2‐crotonic acid)] copper(II) complex [Cu(II)‐BFCA] as neutral carrier is described, which demonstrates excellent potentiometric response characteristics toward thiocyanate ion and anti‐Hofmeister selectivity sequence in following order: SCN−>I−>ClO$\rm{ {_{4}^{-}}}$>Sal−>Br−>NO$\rm{ {_{3}^{-}}}$>Cl−≈NO$\rm{ {_{2}^{-}}}$>SO$\rm{ {_{3}^{2-}}}$>SO$\rm{ {_{4}^{2-}}}$. The electrode shows a near‐Nernstian response for thiocyanate ion in a wide range of 9.0×10−7–1.0×10−1 M with a detection limit 6.8×10−7 M and a slope of −59.1 mV/decade in pH 5.0 of phosphate buffer solution at 20 °C. The influences of lipophilic cationic and anionic additives on the response properties of the electrode were investigated. High sensitivity and wide linear dynamic range were observed for the electrode in the presence of hexadecyltrimethylammoniumborate (HTAB) as a lipophilic cationic additive. The electrode was successfully applied to the determination of thiocyanate ion in waste water and human saliva.
Suspended sediment load estimation and the problem of inadequate data sampling: a fractal view
Authors: Sivakumar Bellie
Published: October 2005

Suspended sediment load estimation at high resolutions is an extremely difficult task, because: (1) it depends on the availability of high‐resolution water discharge and suspended sediment concentration measurements, which are often not available; (2) any errors in the measurements of these two components could significantly influence the accuracy of suspended sediment load estimation; and (3) direct measurements are very expensive. The purpose of this study is to approach this sampling problem from a new perspective of fractals (or scaling), which could provide important information on the transformation of suspended sediment load data from one scale to another. This is done by investigating the possible presence of fractal behaviour in the daily suspended sediment load data for the Mississippi River basin (at St. Louis, Missouri). The presence of fractal behaviour is investigated using five different methods, ranging from general to specific and from mono‐fractal to multi‐fractal: (1) autocorrelation function; (2) power spectrum; (3) probability distribution function; (4) box dimension; and (5) statistical moment scaling function. The results indicate the presence of multi‐fractal behaviour in the suspended sediment load data, suggesting the possibility of transformation of data from one scale to another using a multi‐dimensional model. Copyright © 2005 John Wiley & Sons, Ltd.
Valeric acid extraction with tri‐n‐butyl phosphate impregnated in a macroporous resin: II. Studies in fixed bed columns
Authors: Ruiz Maria Olga , Cabezas José Luis , Escudero Isabel , Coca José
Published: October 2005

Extraction and back‐extraction of valeric acid in a fixed bed packed with Amberlite XAD‐4 resin impregnated with tri‐n‐butyl phosphate were experimentally studied at 25 °C. The effects of the feed flow rate, acid concentration in the feed solution and extractant concentration in the impregnated resin on the breakthrough curves, were investigated. The bed saturation capacity was larger under the conditions of higher extractant concentration in the resin phase and higher acid concentration in the feed solution. A dynamic model that considers intraparticle diffusion and external liquid film diffusion as limiting steps in mass transfer rates was successfully applied. The intraparticle effective diffusivities (10−9 dm2 s−1) were from one to three orders of magnitude lower than the diffusivities in the external liquid film (10−8–10−6 dm2 s−1). A fast and complete back‐extraction of valeric acid from the saturated bed was carried out with sodium hydroxide solutions. The operational life of the impregnated resin was also studied. Copyright © 2005 Society of Chemical Industry