bluuebunny/crossref_metadata_2025_split huggingface dataset:
Decoupling the past from the present attenuates inaction inertia
Authors: van Putten Marijke , Zeelenberg Marcel , van Dijk Eric 
Published: September 2006

AbstractInaction inertia is the phenomenon that one is not likely to act upon an attractive opportunity after having bypassed an even more attractive opportunity. We investigated the boundary conditions of this inaction inertia effect. Based on the mental accounting literature and the transaction decoupling literature we predicted and found in three experiments that tight coupling of the forgone to the current opportunity is a necessary condition for inaction inertia to occur. Inaction inertia decreased when information about the missed opportunity was ambiguous (Experiment 1), when the past opportunity required an extra step to obtain (Experiment 2) and when the past and present opportunity decreased in comparability (Experiment 3). The theoretical and practical implications of the results are discussed in view of the literature on inaction inertia and on judgment and decision‐making. Copyright © 2006 John Wiley & Sons, Ltd.
Risks of hyperthermia associated with hot tub or spa use by pregnant women
Authors: Chambers Christina D. 
Published: September 2006

AbstractThere are a limited number of human studies linking hot tub or spa use during early pregnancy to increased risks for neural tube defects (NTDs) or spontaneous abortion. However, these data can be considered in the context of human studies that have demonstrated an association between high maternal fever in early pregnancy and NTDs. In addition, there is a large volume of animal literature suggesting that, regardless of the heat source, an elevated core maternal temperature at or above the threshold of 2°C over baseline, as well as timing and duration of exposure, are the critical factors in conferring risk. Therefore, the potential for hot tub or spa use to increase core maternal body temperature to risky levels and thus increase the risk for NTDs is likely. A woman who knows or who may not yet be aware that she is pregnant should be advised of the recommended limits of exposure. She should also be aware of the possible variability in hot tub or spa temperature readings and be able to accurately monitor maximum water temperature in the hot tub or spa so that her body temperature can be maintained below 38.9°C. Birth Defects Research (Part A) 76:569–573, 2006. © 2006 Wiley‐Liss, Inc.
Searching for the regulators of human gene expression
Authors: Forton Julian T. , Kwiatkowski Dominic P. 
Published: September 2006

AbstractMany common human traits are believed to be a composite reflection of multiple genetic and non‐genetic factors and the genetic contribution is consequently often difficult to characterise. Recent advances suggest that subtle variation in the regulation of gene expression may contribute to complex human traits. In two reports,1,2 Cheung and colleagues scale up human genetics analysis to an impressive level in a genome‐wide search for the regulators of gene expression. They perform linkage analysis on expression profiles for over 3,500 genes and then employ the HapMap resource3 to take positive findings through to association studies at the genome‐wide level. This work gives new insights into the complexities of gene regulation and the plausibility of genome‐wide study design. BioEssays 28: 968–972, 2006. © 2006 Wiley Periodicals, Inc.
Prolactin in man: a tale of two promoters
Authors: Gerlo Sarah , Davis Julian R.E. , Mager Dixie L. , Kooijman Ron 
Published: September 2006

AbstractThe pituitary hormone prolactin (PRL) is best known for its role in the regulation of lactation. Recent evidence furthermore indicates PRL is required for normal reproduction in rodents. Here, we report on the insertion of two transposon‐like DNA sequences in the human prolactin gene, which together function as an alternative promoter directing extrapituitary PRL expression. Indeed, the transposable elements contain transcription factor binding sites that have been shown to mediate PRL transcription in human uterine decidualised endometrial cells and lymphocytes. We hypothesize that the transposon insertion event has resulted in divergent (pituitary versus extrapituitary) expression of prolactin in primates, and in differential actions of pituitary versus extrapituitary prolactin in lactation versus pregnancy respectively. Importantly, the TE insertion might provide a context for some of the conflicting results obtained in studies of PRL function in mice and man. BioEssays 28: 1051–1055, 2006. © 2006 Wiley Periodicals, Inc.
The rise, fall and renaissance of microsatellites in eukaryotic genomes
Authors: Buschiazzo Emmanuel , Gemmell Neil J. 
Published: September 2006

AbstractMicrosatellites are among the most versatile of genetic markers, being used in an impressive number of biological applications. However, the evolutionary dynamics of these markers remain a source of contention. Almost 20 years after the discovery of these ubiquitous simple sequences, new genomic data are clarifying our understanding of the structure, distribution and variability of microsatellites in genomes, especially for the eukaryotes. While these new data provide a great deal of descriptive information about the nature and abundance of microsatellite sequences within eukaryotic genomes, there have been few attempts to synthesise this information to develop a global concept of evolution. This review provides an up‐to‐date account of the mutational processes, biases and constraints believed to be involved in the evolution of microsatellites, particularly with respect to the creation and degeneration of microsatellites, which we assert may be broadly viewed as a life cycle. In addition, we identify areas of contention that require further research and propose some possible directions for future investigation. BioEssays 28: 1040–1050, 2006. © 2006 Wiley Periodicals, Inc.
Detrimental deletions: mitochondria, aging and Parkinson's disease
Authors: Biskup Saskia , Moore Darren J. 
Published: September 2006

AbstractAs individuals enter their 80s, they are inevitably confronted with the problem of neuronal loss in the brain. The incidence of the common movement disorder ‘mild parkinsonian signs’ (MPS) is approximately 50% over the age of 85 years. It has long been known that the loss of dopaminergic neurons in the substantia nigra pars compacta is a neuropathological hallmark of Parkinson's disease (PD). Recently, two papers1,2 present clear evidence for a high burden of mitochondrial DNA deletions within substantia nigra neurons in aged individuals and individuals with PD, pointing towards a common pathway inevitably leading to neuronal dysfunction and death. BioEssays 28: 963–967, 2006. © 2006 Wiley Periodicals, Inc.
Duplication, divergence and formation of novel protein topologies
Authors: Vogel Christine , Morea Veronica 
Published: September 2006

AbstractThe rearrangement or permutation of protein substructures is an important mode of divergence. Recent work1 explored one possible underlying mechanism called permutation‐by‐duplication, which produces special forms of motif rearrangements called circular permutations. Permutation‐by‐duplication, involving gene duplication, fusion and truncation, can produce fully functional intermediate proteins1 and thus represents a feasible mechanism of protein evolution. In spite of this, circular permutations are relatively rare and we discuss possible reasons for their existence. BioEssays 28: 973–978, 2006. © 2006 Wiley Periodicals, Inc.
Checkpoints and restriction points in bacteria and eukaryotic cells
Authors: Cooper Stephen 
Published: September 2006

AbstractBacterial checkpoints, analogous to those proposed to exist in eukaryotic cells, offer insights into the definition of a checkpoint. Examination of bacterial “checkpoint” or arrest phenomena illustrate problems with a too‐casual application of the checkpoint idea to eukaryotic phenomena. The question raised here is whether there are cellular processes that “check” whether a cellular process is completed. It is possible that many eukaryotic “checkpoints” may not have “checking” functions. Some of the ubiquitous checkpoint phenomena widely described may be merely the result of the inherent incompleteness of earlier events preventing the initiation of subsequent events. BioEssays 28: 1035–1039, 2006. © 2006 Wiley Periodicals, Inc.
Rho GTPase activity zones and transient contractile arrays
Authors: Bement William M. , Miller Ann L. , von Dassow George 
Published: September 2006

AbstractThe Rho GTPases—Rho, Rac and Cdc42—act as molecular switches, cycling between an active GTP‐bound state and an inactive GDP‐bound state, to regulate the actin cytoskeleton. It has recently become apparent that the Rho GTPases can be activated in subcellular zones that appear semi‐stable, yet are dynamically maintained. These Rho GTPase activity zones are associated with a variety of fundamental biological processes including symmetric and asymmetric cytokinesis and cellular wound repair. Here we review the basic features of Rho GTPase activity zones, suggest that these zones represent a fundamental signaling mechanism, and discuss the implications of zone properties from the perspective of both their function and how they are likely to be controlled. BioEssays 28: 983–993, 2006. © 2006 Wiley Periodicals, Inc.
Gas‐Phase Protonation and Deprotonation of Acrylonitrile Derivatives NCCHCHX (X=CH3, NH2, PH2, SiH3)
Authors: Luna Alberto , Mó Otilia , Yáñez Manuel , Gal Jean‐François , Maria P.‐C. , Guillemin Jean‐Claude 
Published: September 2006

AbstractA combined experimental and theoretical study on the gas‐phase basicity and acidity of a series of cyanovinyl derivatives is presented. The gas‐phase basicities and acidities of (NCCHCHX, X=CH3, NH2) were obtained by means of Fourier transform ion cyclotron resonance (FT‐ICR) mass spectrometry techniques. The corresponding calculated values were obtained at the G3B3 level of theory. The effects of exchanging CH3 for SiH3, and NH2 for PH2, were analyzed at the same level of theory. For the neutral molecules, the Z isomer is always the dominant species under standard gas‐phase conditions at 298 K. The loss of the proton from the substituent X was found systematically to be much more favorable than deprotonation of the HCCH linking group. The corresponding isomeric E ion is much more stable than the Z ion, so that only the former should be found in the gas phase. The most significant structural changes upon deprotonation occur for the methyl and amino derivatives because, in both cases, deprotonation of X leads to a significant charge delocalization in the corresponding anion. Protonation takes place systematically at the cyano group, whereby the isomeric E ion is again more stable than the Z ion. Push–pull effects explain the preference of aminoacrylonitrile to be protonated at the cyano group, which also explains the high basicity of this derivative relative to other members of the analyzed series that present rather similar gas‐phase basicities, GB≈780 kJ mol−1, indicating that the different nature of the substituents has only a weak effect on the intrinsic basicity of the cyano group. The cyanovinyl derivatives have a significantly stronger gas‐phase acidity than that of the corresponding vinyl compounds CH2CHX. This acidity‐strengthening effect of the cyano group is attributed to the greater stabilization of the anion with respect to the corresponding neutral compound.
Ca2+– and Ba2+–Ligand Coordinated Unilamellar, Multilamellar, and Oligovesicular Vesicles
Authors: Song Aixin , Jia Xiangfeng , Teng Minmin , Hao Jingcheng 
Published: September 2006

AbstractCa2+‐ and Ba2+‐coordinated vesicle phases were prepared in mixed aqueous solutions of tetradecyldimethylamine oxide (C14DMAO) and calcium oleate (Ca(OA)2) or barium oleate (Ba(OA)2). At the right mixing ratios, metal–ligand coordination between Ca(OA)2 or Ba(OA)2 and C14DMAO results in the formation of molecular bilayers due to the reduction in area per head group. Ca2+ and Ba2+ tightly associate to the head groups of surfactants and in this system the bilayer membranes are not shielded by excess salts. The structures of the birefringent samples of the Ca(OA)2/C14DMAO/H2O and Ba(OA)2/C14DMAO/H2O systems were determined by freeze‐fracture transmission electron microscopy (FF‐TEM), small‐angle X‐ray scattering (SAXS), and rheological measurements to consist of unilamellar, multilamellar, and oligovesicular vesicles. The coordination between C14DMAO and Ba(OA)2 or Ca(OA)2 plays an important role in the formation of the vesicles, which was easily confirmed by studying the phase behavior of the KOA/C14DMAO/H2O system in which only the L1 phase forms, due to the absence of coordination between KOA and C14DMAO. A mechanism is proposed that accounts for the formation of these new metal–ligand coordinated vesicles.
Structure of the α‐Homo‐DNA:RNA Duplex and the Function of Twist and Slide To Catalogue Nucleic Acid Duplexes
Authors: Nauwelaerts Koen , Lescrinier Eveline , Herdewijn Piet 
Published: September 2006

AbstractHigh‐resolution NMR studies of an α‐homo‐DNA:RNA duplex reveal the formation of a right‐handed parallel‐oriented helix. It differs significantly from a standard A‐ or B‐type helix by a small twist value (26.2°), which leads to a helical pitch of 13.7 base pairs per helical turn, a negative inclination (−1.78 Å) and a large x displacement (5.90 Å). The rise (3.4 Å) is similar to that found in B‐DNA. The solution of this new helix structure has stimulated us to develop a mathematical and geometrical model based on slide and twist parameters to describe nucleic acid duplexes. All existing duplexes can be positioned within this landscape, which can be used to understand the helicalization process.
Iridium(III) Silyl Alkyl and Iridacyclic Compounds Supported by 4,4′‐Di‐tert‐butyl‐2,2′‐bipyridyl
Authors: Sau Yiu‐Keung , Lee Hung‐Kay , Williams Ian D. , Leung Wa‐Hung 
Published: September 2006

AbstractTreatment of IrCl3⋅x H2O with one equivalent of 4,4′‐di‐tert‐butyl‐2,2′‐bipyridyl (dtbpy) in N,N‐dimethylformamide (dmf) afforded [IrCl3(dmf)(dtbpy)] (1). Alkylation of 1 with Me3SiCH2MgCl resulted in CSi cleavage of the Me3SiCH2 group and formation of the IrIII silyl dialkyl compound [Ir(CH2SiMe3)(dtbpy)(Me)(SiMe3)] (2), which reacted with tBuNC to afford [Ir(tBuNC)(CH2SiMe3)(dtbpy)(Me)(SiMe3)] ([2(tBuNC)]). Reaction of 2 with phenylacetylene afforded dimeric [{Ir(CCPh)(dtbpy)(SiMe3)}2(μ‐CCPh)2] (3), in which the bridging PhCC− ligands are bound to Ir in a μ‐σ:π fashion. Alkylation of 1 with PhMe2CCH2MgCl afforded the cyclometalated compound [Ir(dtbpy)(CH2CMe2C6H4)(2‐C6H4CMe3)] (4), which features an agostic interaction between the Ir center and the 2‐tert‐butylphenyl ligand. The cyclic voltammogram of 4 in CH2Cl2 shows a reversible IrIV–IrIII couple at about 0.02 V versus ferrocenium/ferrocene. Oxidation of 4 in CH2Cl2 with silver triflate afforded an IrIV species that exhibits an anisotropic electron paramagnetic resonance (EPR) signal in CH2Cl2 glass at 4 K with g∥=2.430 and g⊥=2.110. Protonation of 4 with HCl and p‐toluenesulfonic acid (HOTs) afforded [{Ir(dtbpy)(CH2CMe2Ph)Cl}2(μ‐Cl)2] (5) and [Ir(dtbpy)(CH2CMe2Ph)(OTs)2] (6), respectively. Reaction of 5 with Li[BEt3H] gave the cyclometalated complex [{Ir(dtbpy)(CH2CMe2C6H4)}2(μ‐Cl)2] (7). Reaction of 4 with tetracyanoethylene in refluxing toluene resulted in electrophilic substitution of the iridacycle by C2(CN)3 with formation of [Ir(dtbpy)(CH2CMe2C6H3{4‐C2(CN)3})(2‐C6H4CMe3)] (8). Reaction of 4 with diethyl maleate in refluxing toluene gave the iridafuran compound [Ir(dtbpy)(CH2CMe2C6H4){κ2(C,O)‐C(CO2Et)CH(CO2Et)}] (9). Treatment of 9 with 2,6‐dimethylphenyl isocyanide (xylNC) led to cleavage of the iridafuran ring and formation of [Ir(dtbpy)(CH2CMe2C6H4){C(CO2Et)CH(CO2Et)}(xylNC)] (10). Protonation of 9 with HBF4 afforded the dinuclear neophyl complex [(Ir(dtbpy)(CH2CMe2Ph){κ2(C,O)‐C(CO2Et)CH(CO2Et)})2][BF4]2 (11). The solid‐state structures of complexes 2–5 and 8–11 have been determined.
N‐Fusion Reaction Sequence of Heptaphyrin(1.1.1.1.1.1.1): Singly, Doubly, and Quadruply N‐Fused Heptaphyrins
Authors: Saito Shohei , Osuka Atsuhiro 
Published: September 2006

Abstractmeso‐Heptakis(pentafluorophenyl) heptaphyrin(1.1.1.1.1.1.1) (1) was prepared by a stepwise route in 39 % yield and its unique N‐fusion reaction (NFR) sequence has been revealed; this reaction leads to singly‐, doubly‐, and quadruply N‐fused heptaphyrins (4, 5, and 6) in good yields. These transformations are facilitated by the inherent conformational distortion of 1 as well as the distorted, folded conformations of N‐fused heptaphyrins 4 and 5. The proximate arrangement of the three pyrrole units in 6 allowed for the formation of the tripyrrolylboron(III) complexes 7, 8, and 9 with unique coordination features. Molecules 1, 5, and 9 were structurally characterized by X‐ray crystallography. In addition, the boron complexes 7, 8, and 9 displayed weak but distinct fluorescence in the near infrared region.
Luminescent PtII(bipyridyl)(diacetylide) Chromophores with Pendant Binding Sites as Energy Donors for Sensitised Near‐Infrared Emission from Lanthanides: Structures and Photophysics of PtII/LnIII Assemblies
Authors: Ronson Tanya K. , Lazarides Theodore , Adams Harry , Pope Simon J. A. , Sykes Daniel , Faulkner Stephen , Coles Simon J. , Hursthouse Michael B. , Clegg William , Harrington Ross W. , Ward Michael D. 
Published: September 2006

AbstractThe complexes [Pt(bipy){CC‐(4‐pyridyl)}2] (1) and [Pt(tBu2bipy){CC‐(4‐pyridyl)}2] (2) and [Pt(tBu2‐bipy)(CC‐phen)2] (3) all contain a Pt(bipy)(diacetylide) core with pendant 4‐pyridyl (1 and 2) or phenanthroline (3) units which can be coordinated to {Ln(diketonate)3} fragments (Ln = a lanthanide) to make covalently‐linked PtII/LnIII polynuclear assemblies in which the PtII chromophore, absorbing in the visible region, can be used to sensitise near‐infrared luminescence from the LnIII centres. For 1 and 2 one‐dimensional coordination polymers [1⋅Ln(tta)3]∞ and [2⋅Ln(hfac)3]∞ are formed, whereas 3 forms trinuclear adducts [3⋅{Ln(hfac)3}2] (tta=anion of thenoyl‐trifluoroacetone; hfac=anion of hexafluoroacetylacetone). Complexes 1–3 show typical PtII‐based 3MLCT luminescence in solution at ≈510 nm, but in the coordination polymers [1⋅Ln(tta)3]∞ and [2⋅Ln(hfac)3]∞ the presence of stacked pairs of PtII units with short Pt⋅⋅⋅Pt distances means that the chromophores have 3MMLCT character and emit at lower energy (≈630 nm). Photophysical studies in solution and in the solid state show that the 3MMLCT luminescence in [1⋅Ln(tta)3]∞ and [2⋅Ln(hfac)3]∞ in the solid state, and the 3MLCT emission of [3⋅{Ln(hfac)3}2] in solution and the solid state, is quenched by Pt→Ln energy transfer when the lanthanide has low‐energy f–f excited states which can act as energy acceptors (Ln=Yb, Nd, Er, Pr). This results in sensitised near‐infrared luminescence from the LnIII units. The extent of quenching of the PtII‐based emission, and the Pt→Ln energy‐transfer rates, can vary over a wide range according to how effective each LnIII ion is at acting as an energy acceptor, with YbIII usually providing the least quenching (slowest Pt→Ln energy transfer) and either NdIII or ErIII providing the most (fastest Pt→Ln energy transfer) according to which one has the best overlap of its f–f absorption manifold with the PtII‐based luminescence.
In Silico ADMET Traffic Lights as a Tool for the Prioritization of HTS Hits
Authors: Lobell Mario , Hendrix Martin , Hinzen Berthold , Keldenich Jörg , Meier Heinrich , Schmeck Carsten , Schohe‐Loop Rudolf , Wunberg Tobias , Hillisch Alexander 
Published: September 2006

AbstractThe need for in silico characterization of HTS hit structures as part of a data‐driven hit‐selection process is demonstrated. A solution is described in the form of an in silico ADMET traffic light and PhysChem scoring system. This has been extensively validated with in‐house data at Bayer, published data, and a collection of launched small‐molecule oral drugs.
A new type of susceptibility‐artefact‐based magnetic resonance angiography: intra‐arterial injection of superparamagnetic iron oxide particles (SPIO) A Resovist® in combination with TrueFisp imaging: a feasibility study
Authors: Maes Robbert M. , Lewin Jonathan S. , Duerk Jeffrey L. , Misselwitz Bernd , Kiewiet Cunera J. M. , Wacker Frank K. 
Published: September 2006

AbstractThe goal of this study was to evaluate the use of super paramagnetic particles of iron oxide (SPIO) as a dark blood contrast agent, in combination with a bright blood steady‐state free precession sequence for magnetic resonance angiography (MRA), in an animal model. The original concentration of the SPIO of 500 mmol Fe/l and dilutions to 250, 125, 60, 30, 10 and 5 mmol Fe/l were intra‐arterially injected into the aorta of a pig. Then the dilution of 10 mmol Fe/l was chosen for repeated intra‐arterial injections into two pigs. During these intra‐arterial SPIO injections MR images were acquired with a 1.5 T scanner. Signal intensity measurements were performed in the aorta. The signal‐to‐noise ratio during SPIO bolus passage was significantly less than during baseline conditions (Fisher's F‐ratio 159.8, p < 0.005) or the recovery signal‐to‐noise ratio (Fisher's F‐ratio 144.6, p < 0.005). Also, confirmation of flow distal to the catheter‐tip position was possible. The use of SPIO as a dark blood agent in combination with a bright blood MR imaging sequence is feasible. Temporary loss of intraluminal signal occurs due to local decrease of the signal because of induction of local inhomogeneities after mixture the present blood and SPIO solution. It provides immediate information about blood flow distal to the catheter and is a potentially useful to guide intravascular MR‐interventional procedures. Copyright © 2006 John Wiley & Sons Ltd.
An HPLC/mass spectrometry platform for the development of multimodality contrast agents and targeted therapeutics: prostate‐specific membrane antigen small molecule derivatives
Authors: Humblet Valerie , Misra Preeti , Frangioni John V. 
Published: September 2006

AbstractThe production of disease‐targeted agents requires the covalent conjugation of a targeting molecule with a contrast agent or therapeutic, followed by purification of the product to homogeneity. Typical targeting molecules, such as small molecules and peptides, often have high charge‐to‐mass ratios and/or hydrophobicity. Contrast agents and therapeutics themselves are also diverse, and include lanthanide chelates for MRI, 99mTc chelates for SPECT, 90Y chelates for radiotherapy, 18F derivatives for PET, and heptamethine indocyanines for near‐infrared fluorescent optical imaging. We have constructed a general‐purpose HPLC/mass spectrometry platform capable of purifying virtually any targeted agent for any modality. The analytical sub‐system is composed of a single dual‐head pump that directs mobile phase to either a hot cell for the purification of radioactive agents or to an ES‐TOF MS for the purification of nonradioactive agents. Nonradioactive agents are also monitored during purification by ELSD, absorbance and fluorescence. The preparative sub‐system is composed of columns and procedures that permit rapid scaling from the analytical system. To demonstrate the platform's utility, we describe the preparation of five small molecule derivatives specific for prostate‐specific membrane antigen (PSMA): a gadolinium derivative for MRI, indium, rhenium and technetium derivatives for SPECT, and an yttrium derivative for radiotherapy. All five compounds are derived from a highly anionic targeting ligand engineered to have a single nucleophile for N‐hydroxysuccinimide‐based conjugation. We also describe optimized column/mobile phase combinations and mass spectrometry settings for each class of agent, and discuss strategies for purifying molecules with extreme charge and/or hydrophobicity. Taken together, our study should expedite the development of disease‐targeted, multimodality diagnostic and therapeutic agents. Copyright © 2006 John Wiley & Sons, Ltd.