bluuebunny/crossref_metadata_2025 huggingface dataset:
Gaining Selectivity by Combining Catalysts: Sequential versus Recycling Processes
Authors: Fransson Linda , Moberg Christina
Published: October 2010

Highly enantioenriched chiral products may be obtained by using a combination of two moderately selective catalysts. Sequential enantioselective transformations comprising an asymmetric reaction followed by a kinetic resolution of the scalemic product mixture obtained in the first step are well known. In such processes, the minor, undesired enantiomer is transformed to a compound that can be more easily separated from the major enantiomer. Although chiral compounds may be obtained with high enantiopurity by such coupled processes, the yield of the desired product necessarily suffers. Recycling processes, whereby the minor enantiomer is transformed to prochiral starting material, avoid this limitation. In this Minireview, different types of sequential catalytic processes using two reinforcing catalysts are surveyed and their advantages and limitations discussed in relation to recycling processes.
Prototype Supported Metal Cluster Catalysts: Ir4 and Ir6
Authors: Uzun Alper , Dixon David A. , Gates Bruce C.
Published: October 2010

The following is a review of the synthesis, chemistry, and catalytic properties of small, well‐defined supported metal clusters, Ir4 and Ir6. These supported clusters are synthesized either by adsorption of ligated molecular iridium clusters with tetrahedral and octahedral frameworks, for Ir4 and Ir6, respectively, or by adsorption of single‐iridium‐atom complexes followed by treatment to form clusters on the supports. The most insightful characterizations of supported metal clusters have been carried out by infrared and X‐ray absorption spectroscopies and aberration‐corrected scanning transmission electron microscopy. Reactions of the supported clusters include ligand modifications and ligand removal, oxidative fragmentation, and migration leading to metal aggregation. Reactivities and catalytic properties of the clusters (e.g., for olefin hydrogenation) depend on the cluster size and the support (which acts as a ligand) and are distinct from those of supported particles that resemble bulk iridium. Transient spectroscopic data illustrate that the structures of the active species in ethylene hydrogenation catalysis switch reversibly from Ir4 to single‐iridium‐atom complexes in response to changes in the ethylene/H2 ratio in the gas phase. Density functional theory has been used to predict properties of these clusters, notably their ability to add hydrogen, and the agreement between theory and experiment is good. Recent advances in the characterization of supported Ir4 and Ir6 clusters have been crucial in the elucidation of their behavior, and these methods apply as well to the more complicated structures of industrial supported metal catalysts.
Chemoenzymatic One‐Pot Synthesis of both (R)‐ and (S)‐Aryl‐1,2‐ethanediols
Authors: Bencze László Csaba , Paizs Csaba , Toşa Monica Ioana , Irimie Florin Dan , Rétey János
Published: October 2010

Both enantiomers of various 1‐aryl‐1,2‐ethanediols have been prepared in a one‐pot method from the corresponding arylethanones through the combination of chemical and enzymatic reactions. A range of aryl groups, phenyl, 4‐chlorophenyl, benzo[b]thiophene‐3‐yl, and benzofuran‐2‐yl, were used. The highly enantiomerically enriched (R)‐ and (S)‐1‐aryl‐1,2‐ethanediols were obtained with excellent yields, calculated for the arylethanones.
Finding relevant clustering directions in high‐dimensional data using Particle Swarm Optimization
Authors: Marini Federico , Walczak Beata
Published: October 2010

A method based on Particle Swarm Optimization (PSO) is proposed and described for finding subspaces that carry meaningful information about the presence of groups in high‐dimensional data sets. The advantage of using PSO is that not only the variables that are responsible for the main data structure are identified but also other subspaces corresponding to local optima. The characteristics of the method are shown on two simulated data sets and on a real matrix coming from the analysis of genomic microarrays. In all cases, PSO allowed to explore different subspaces and to discover meaningful structures in the analyzed data. Copyright © 2010 John Wiley & Sons, Ltd.
Preventing over‐fitting in PLS calibration models of near‐infrared (NIR) spectroscopy data using regression coefficients
Authors: Gowen A. A. , Downey G. , Esquerre C. , O'Donnell C. P.
Published: October 2010

Selection of the number of latent variables (LVs) to include in a partial least squares (PLS) model is an important step in the data analysis. Inclusion of too few or too many LVs may lead to, respectively, under or over‐fitting of the data and subsequently result in poor future model performance. One well‐known sign of over‐fitting is the appearance of noise in regression coefficients; this often takes the form of a reduction in apparent structure and the presence of sharp peaks with a high degree of directional oscillation, features which are usually estimated subjectively. In this work, a simple method for quantifying the shape and size of a regression coefficient is presented. This measure can be combined with an indicator of model bias (e.g. root mean square error) to aid in estimation of the appropriate number of LVs to include in a PLS model. The performance of the proposed method is evaluated on simulated and and real NIR spectroscopy datasets sets and compared with several existing methods. Copyright © 2010 John Wiley & Sons, Ltd.
Preparation and Investigation of Vitamin B6‐Derived Aminopyridinol Antioxidants
Authors: Serwa Remigiusz , Nam Tae‐gyu , Valgimigli Luca , Culbertson Sean , Rector Christopher L. , Jeong Byeong‐Seon , Pratt Derek A. , Porter Ned A.
Published: October 2010

3‐Pyridinols bearing amine substitution para to the hydroxylic moiety have previously been shown to inhibit lipid peroxidation more effectively than typical phenolic antioxidants, for example, α‐tocopherol. We report here high‐yielding, large‐scale syntheses of mono‐ and bicyclic aminopyridinols from pyridoxine hydrochloride (i.e., vitamin B6). This approach provides straightforward, scaleable access to novel, potent, molecular scaffolds whose antioxidant properties have been investigated in homogeneous solutions and in liposomal vesicles. These molecular aggregates mimic cell membranes that are the targets of oxidative damage in vivo.
On the Trimerization of Cyanoacetylene: Mechanism of Formation of Tricyanobenzene Isomers and Laboratory Detection of Their Radio Spectra
Authors: Hopf Henning , Mlynek Cornelia , McMahon Robert J. , Menke Jessica L. , Lesarri Alberto , Rosemeyer Michael , Grabow Jens‐Uwe
Published: October 2010

In support of a deeper understanding of the chemistry of cyanoacetylene—a known constituent of planetary atmospheres and interstellar space—theoretical and experimental studies address the chemical mechanism of dimerization and trimerization, and provide high‐resolution rotational spectra of two of the trimeric products, 1,2,3‐ and 1,2,4‐tricyanobenzene. Analysis of the rotational spectra is particularly challenging because of quadrupolar coupling from three 14N nuclei. The laboratory rotational spectra provide the basis for future searches for these polar aromatic compounds in interstellar space by radio astronomy.
Oligo‐m‐phenyleneoxalamide Copper(II) Mesocates as Electro‐Switchable Ferromagnetic Metal–Organic Wires
Authors: Pardo Emilio , Ferrando‐Soria Jesús , Dul Marie‐Claire , Lescouëzec Rodrigue , Journaux Yves , Ruiz‐García Rafael , Cano Joan , Julve Miguel , Lloret Francesc , Cañadillas‐Delgado Laura , Pasán Jorge , Ruiz‐Pérez Catalina
Published: October 2010

Double‐stranded copper(II) string complexes of varying nuclearity, from di‐ to tetranuclear species, have been prepared by the CuII‐mediated self‐assembly of a novel family of linear homo‐ and heteropolytopic ligands that contain two outer oxamato and either zero (1 b), one (2 b), or two (3 b) inner oxamidato donor groups separated by rigid 2‐methyl‐1,3‐phenylene spacers. The X‐ray crystal structures of these CuIIn complexes (n=2 (1 d), 3 (2 d), and 4 (3 d)) show a linear array of metal atoms with an overall twisted coordination geometry for both the outer CuN2O2 and inner CuN4 chromophores. Two such nonplanar all‐syn bridging ligands 1 b–3 b in an anti arrangement clamp around the metal centers with alternating M and P helical chiralities to afford an overall double meso‐helicate‐type architecture for 1 d–3 d. Variable‐temperature (2.0–300 K) magnetic susceptibility and variable‐field (0–5.0 T) magnetization measurements for 1 d–3 d show the occurrence of S=nSCu (n=2–4) high‐spin ground states that arise from the moderate ferromagnetic coupling between the unpaired electrons of the linearly disposed CuII ions (SCu=1/2) through the two anti m‐phenylenediamidate‐type bridges (J values in the range of +15.0 to 16.8 cm−1). Density functional theory (DFT) calculations for 1 d–3 d evidence a sign alternation of the spin density in the meta‐substituted phenylene spacers in agreement with a spin polarization exchange mechanism along the linear metal array with overall intermetallic distances between terminal metal centers in the range of 0.7–2.2 nm. Cyclic voltammetry (CV) and rotating‐disk electrode (RDE) electrochemical measurements for 1 d–3 d show several reversible or quasireversible one‐ or two‐electron steps that involve the consecutive metal‐centered oxidation of the inner and outer CuII ions (SCu=1/2) to diamagnetic CuIII ones (SCu=0) at relatively low formal potentials (E values in the range of +0.14 to 0.25 V and of +0.43 to 0.67 V vs. SCE, respectively). Further developments may be envisaged for this family of oligo‐m‐phenyleneoxalamide copper(II) double mesocates as electroswitchable ferromagnetic ‘metal–organic wires’ (MOWs) on the basis of their unique ferromagnetic and multicenter redox behaviors.
The Dynamic Chemistry of Molecular Borromean Rings and Solomon Knots
Authors: Meyer Cari D. , Forgan Ross S. , Chichak Kelly S. , Peters Andrea J. , Tangchaivang Nicholas , Cave Gareth W. V. , Khan Saeed I. , Cantrill Stuart J. , Stoddart J. Fraser
Published: October 2010

The dynamic solution equilibria between molecular Borromean rings (BRs) and Solomon knots (SKs), assembled from transition metal‐templated macrocycles, consisting of exo‐bidentate bipyridyl and endo‐tridentate diiminopyridyl ligands, have been examined with respect to the choice of the metal template and reaction conditions employed in the synthesis of the metalated BRs, otherwise known as Borromeates. Three new Borromeates, their syntheses templated by CuII, CoII, and MnII, have been characterized extensively (two by X‐ray crystallography) to the extent that the metal centers in the assemblies have been shown to be distanced sufficiently from each other not to communicate. The solid‐state structure of the CoII–Borromeate reveals that six MeOH molecules, arranged in a [OH⋅⋅⋅O] hydrogen bonded, chair‐like conformation, are located within its oxophilic central cavity. When a mixture of CuII and ZnII is used as the source of templation, there exists a dynamic equilibrium, in MeOH at room temperature, between a mixed‐metal BR and a SK, from which the latter has been fractionally crystallized. By employing appropriate synthetic protocols with ZnII or CdII as the template, significant amounts of SKs are formed alongside BRs. Modified crystallization conditions resulted in the isolation of both an all‐zinc BR and an all‐zinc SK, crystals of which can be separated manually, leading to the full characterization of the all‐zinc SK by 1H NMR spectroscopy and X‐ray crystallography. This doubly interlocked [2]catenate has been identified retrospectively in recorded spectra, where it was attributed previously to a Borromeate with a ZnII cation coordinated to the oxophilic interior walls of the ensemble. Interestingly, these ZnII‐templated assemblies do not interconvert in MeOH at room temperature, indicating the significant influence of both the metal template and solvent on the solution equilibria. It would also appear that d10 metal ions favor SK formation—no evidence of CuII‐, CoII‐, or MnII‐templated SKs has been found, yet a 1:0.9 ratio of BR:SK has been identified by 1H NMR spectroscopy when CdII is used as the template.
Modulation of Photoswitching Profiles by 10,11‐Dialkoxymethyl Substituents in C2‐Symmetric Dibenzosuberane‐Based Helicenes
Authors: Chen Wen‐Ching , Lin Po‐Chiao , Chen Chien‐Hsiang , Chen Chien‐Tien
Published: October 2010

A series of C2‐symmetric, 10,11‐disubstituted dibenzosuberane (DBS)‐based helicenes 6 a–c with a common 7‐bromo‐α‐tetralin‐based bottom fragment were synthesized. Their absolute stereochemistry was determined to be 10R,11R,P after reductive desulfurization of the corresponding (10R,11R,1′S)‐episulfides with complete stereospecificity. Photoisomerization of the diastereomerically pure (P)‐6 c in hexane led to virtually exclusive formation of the opposite M‐form diastereomer (P/M′, <1:>99) at 290 nm. The preferential return of (M′)‐6 c to (P)‐6 c was also achieved with high selectivity (P/M′, 90:10) at 330 nm. Molecular simulations of (P)‐6 c and (M′)‐6 c with both DBS conformations suggest that the selectivities of photoswitching are controlled by the conformation of the top DBS template as evidenced by their 1H NMR spectra. Doping 6 c into a nematic liquid crystal (E7) led to a cholesteric mesophase with modulated pitches, reversible helical senses, and with a switch memory of ternary logic.
Dynamic spatiotemporal gene expression in embryonic mouse thalamus
Authors: Suzuki‐Hirano Asuka , Ogawa Masaharu , Kataoka Ayane , Yoshida Aya C. , Itoh Daisuke , Ueno Masaki , Blackshaw Seth , Shimogori Tomomi
Published: October 2010

The anatomy of the mammalian thalamus is characterized by nuclei, which can be readily identified in postnatal animals. However, the molecular mechanisms that guide specification and differentiation of neurons in specific thalamic nuclei are still largely unknown, and few molecular markers are available for most of these thalamic subregions at early stages of development. We therefore searched for patterned gene expression restricted to specific mouse thalamic regions by in situ hybridization during the onset of thalamic neurogenesis (embryonic [E] days E10.5–E12.5). To obtain correct regional information, we used Shh as a landmark and compared spatial relationships with the zona limitans intrathalamica (Zli), the border of the p2 and p3 compartments of the diencephalon. We identified genes that are expressed specifically in the ventricular zone of the thalamic neuroepithelium and also identified a number of genes that already exhibited regional identity at E12.5. Although many genes expressed in the mantle regions of the thalamus at E12.5 showed regionally restricted patterns, none of these clearly corresponded to individual thalamic nuclei. We next examined gene expression at E15.5, when thalamocortical axons (TCAs) project from distinct regions of the thalamus and reach their targets in the cerebral cortex. Regionally restricted patterns of gene expression were again seen for many genes, but some regionally bounded expression patterns in the early postnatal thalamus had shifted substantially by E15.5. These findings reveal that nucleogenesis in the developing thalamus is associated with selective and complex changes in gene expression and provide a list of genes that may actively regulate the development of thalamic nuclei. J. Comp. Neurol. 519:528–543, 2011. © 2010 Wiley‐Liss, Inc.
A molecular mechanism that regulates medially oriented axonal growth of upper layer neurons in the developing neocortex
Authors: Zhao Hong , Maruyama Takuro , Hattori Yuki , Sugo Noriyuki , Takamatsu Hyota , Kumanogoh Atsushi , Shirasaki Ryuichi , Yamamoto Nobuhiko
Published: October 2010

During development, cortical neurons extend axons to their targets based on their laminar locations and cell types. Here we studied the molecular mechanism that regulates medially oriented axonal growth of upper layer neurons in the developing mouse cortex. Upper layer neurons were labeled with enhanced yellow fluorescent protein (EYFP) by in utero electroporation at E15.5. Cortical slices containing EYFP‐labeled cells were dissected at E16, when axonal outgrowth from upper layer neurons is not initiated, and were cultured in an organotypic manner. After 3 days in culture, most labeled cells were found to extend axons medially in the same fashion as those observed in vivo. This oriented growth was disrupted when the lateral side of the cortical slice was removed, indicating that a laterally located repellent is involved in the medially oriented growth. Strikingly, the medially directed growth within the slices was reduced in the medium containing Semaphorin3A (Sema3A) or soluble form of Neuropilin‐1 (Npn1), a receptor for Sema3A. Importantly, we found that Sema3A was expressed in a gradient from lateral‐high to medial‐low within the cortex, and callosal axons originating from upper layer neurons uniquely expressed Npn1. Consistent with these findings, ectopically expressed Sema3A repelled medially oriented elongation of upper layer cell axons in vivo. These results therefore suggest the operation of a repulsive mechanism for medially oriented axon growth of upper layer neurons, and further point to a role for a gradient expression of Sema3A in this directional axon growth along the mediolateral axis within the neocortex. J. Comp. Neurol. 519:834–848, 2011. © 2010 Wiley‐Liss, Inc.
Complexation of Phenol and Thiophenol by Amine N‐Oxides: Isothermal Titration Calorimetry and ab Initio Calculations
Authors: Cuypers Ruud , Murali Sukumaran , Marcelis Antonius T. M. , Sudhölter Ernst J. R. , Zuilhof Han
Published: October 2010

To develop a new solvent‐impregnated resin (SIR) system for removal of phenols from water, the complex formation of dimethyldodecylamine N‐oxide (DMDAO), trioctylamine N‐oxide (TOAO), and tris(2‐ethylhexyl)amine N‐oxide (TEHAO) with phenol (PhOH) and thiophenol (PhSH) is studied. To this end we use isothermal titration calorimetry (ITC) and quantum chemical modeling (on B3LYP/6‐311G(d,p)‐optimized geometries: B3LYP/6‐311+G(d,p), B3LYP/6‐311++G(2d,2p), MP2/6‐311+G(d,p), and spin component scaled (SCS) MP2/6‐311+G(d,p); M06‐2X/6‐311+G(d,p)//M06‐2X/6‐311G(d,p), MP2 with an extrapolation to the complete basis set limit (MP2/CBS), as well as CBS‐Q). The complexes are analyzed in terms of structural (e.g., bond lengths) and electronic elements (e.g., charges). Furthermore, complexation and solvent effects (in benzene, toluene, and mesitylene) are investigated by ITC measurements, yielding binding constants K, enthalpies ΔH0, Gibbs fre energies ΔG0, and entropies ΔS0 of complex formation, and stoichiometry N. The ITC measurements revealed strong 1:1 complex formation between both DMDAO–PhOH and TOAO–PhOH. The binding constant (K=1.7–5.7×104 M−1) drops markedly when water‐saturated toluene was used (K=5.8×103 M−1), and π–π interaction with the solvent is shown to be relevant. Quantum mechanical modeling confirms formation of stable 1:1 complexes with linear hydrogen bonds that weaken on attachment of electron‐withdrawing groups to the amine N‐oxide moiety. Modeling also showed that complexes with PhSH are much weaker than those with PhOH, and in fact too weak for ITC determination. CBS‐Q incorrectly predicts equal or even higher binding enthalpies for PhSH than for PhOH, which invalidates it as a benchmark for other calculations. Data from the straightforward SCS‐MP2 method without counterpoise correction show very good agreement with the MP2/CBS values.
Fluorescence Blinking of the RC–LH1 Complex from Rhodopseudomonas palustris
Authors: Unterkofler Sarah , Pflock Tobias , Southall June , Cogdell Richard J. , Köhler Jürgen
Published: October 2010

We investigate fluorescence blinking of individual RC–LH1 (reaction‐centre–light‐harvesting 1) complexes from the photosynthetic purple bacterium Rhodopseudomonas palustris. For both the on‐ and off‐periods the telegraph‐like intermittency of the fluorescence intensity follows power‐law statistics with exponents between 1 and 2. Yet, this behaviour was only observed for a small fraction of the complexes studied. We argue that the majority of the complexes reside in a prolonged on‐state, due to a mechanism that is similar to the Coulomb blockade in semiconductor quantum dots, and which results here from the photoinduced charges located within the RC upon photoexcitation of the LH1 antenna.
IFDAT—International forum for drug and alcohol testing, 12–14 April 2010, Barcelona, Spain
Authors: Kenney JD Josephine Elizabeth , Björklöv Per
Published: October 2010

The second programme of its kind globally, the highly successful, collaborative, productive and energizing IFDAT—International Forum for Drug and Alcohol Testing, was held in Barcelona, Spain, from 12–14 April. IFDAT was attended by over 100 delegates, conference sponsors and exhibitors from the international workplace drug and alcohol testing industry. Representing over 20 countries, the delegate professionals, speakers, and presenters included employers, service agents, an international publisher, and workplace testing suppliers. The purpose of the forum was to exchange knowledge, learn about new technology, and support the evolution and growth of the emerging international workplace drug and alcohol testing industry. This purpose was accomplished. Delegates from around the globe exchanged their experiences and thoughts about effective workplace drug testing programmes over two days of intensive presentations and panel discussions. The presenters and panelists included drug and alcohol testing professionals, authorities, and intellectuals from around the world.

IFDAT conferences are planned for every 18 months, and the next Forum, to be held in Houston, Texas, USA is in the planning process for 2011. Copyright © 2010 John Wiley & Sons, Ltd.
Drug metabolism in the horse: a review
Authors: Scarth James P. , Teale Phil , Kuuranne Tiia
Published: October 2010

A detailed understanding of equine drug metabolism is important for detection of drug abuse in horseracing and also in veterinary drug development and practice. To date, however, no comprehensive review of equine drug metabolism has been published.

The majority of literature regarding equine drug metabolite profiles is derived from sports drug detection research and is generally targeted at detecting marker metabolites of drug abuse. However, the bulk of the literature on equine drug metabolism enzymology is derived from veterinary studies aimed at determining the molecular basis of metabolism. In this article, the phase 1 and 2 metabolisms of seven of the most important classes of drugs monitored in horseracing are reviewed, including: anabolic‐androgenic steroids (AAS), β2‐agonists, stimulants, sedatives/tranquilizers, local anesthetics, non‐steroidal anti‐inflammatory analgesics (NSAIDS)/cyclooxygenase‐2 (COX‐2) inhibitors, and opioid analgesics. A summary of the literature relating to the enzymology of drug metabolism in this species is also be presented.

The future of equine drug metabolism in the area of doping research will be influenced by several factors, including: a possible move towards the increased use of blood and other alternative testing matrices; the development of assays based on intact drug conjugates; the increasing threat of ‘designer’ and herbal‐ based products; advances in the use ofin vitrotechnologies; the increased use of liquid‐chromatography/high‐resolution mass spectrometry; and the possibility of screening using ‘omics’ approaches. Also, the recent cloning of a range of equine cytochrome P450 (CYP) enzymes opens up the potential for carrying out more detailed mechanistic pharmacological and toxicological veterinary studies. Copyright © 2010 John Wiley & Sons, Ltd.
Stable isotope ratio profiling of testosterone preparations
Authors: Cawley Adam , Collins Michael , Kazlauskas Rymantas , Handelsman David J , Heywood Robert , Longworth Mitchell , Arenas‐Queralt Andrea
Published: October 2010

Gas chromatography‐combustion‐isotope ratio mass spectrometry (GC‐C‐IRMS) is the preferred method of confirming the administration of exogenous testosterone by athletes. This relies on synthetic testosterone preparations being depleted in 13C compared to natural testosterone. There is concern, however, about the existence of synthetic testosterone products that are unexpectedly 13C‐enriched and which may allow athletes to circumvent the current GC‐C‐IRMS test. Further to the reported studies of legitimate pharmaceutical‐grade testosterone products, a detailed analysis of seized materials from border‐level seizures was required to obtain intelligence concerning trends in ‘black market’ testosterone manufacture and distribution. The sample set collected for this study between 2006 and 2009 inclusive provided a δ13C range (n = 266) of − 22.9‰ to − 32.6‰ with mean and median values of − 28.4‰ and − 28.6‰, respectively. Within this distribution there were 24 samples (9%) confirmed to have δ13C values in the range reported for endogenous urinary steroid metabolites (≥− 25.8‰). The benefit of δ13C profiling for testosterone preparations was demonstrated by the ability to identify specific seized products that can be target tested for future intelligence purposes.

In addition, the potential of stable hydrogen isotope ratio (2H/1H; δ2H) discrimination to complement δ13C analysis was investigated. Methodologies for the determination of δ2H values by gas chromatography‐thermal conversion‐isotope ratio mass spectrometry (GC‐TC‐IRMS) were developed to provide a δ2H range (n = 173) of − 177‰ to − 268‰ with mean and median values of − 231‰ and − 234‰, respectively. Copyright © 2010 John Wiley & Sons, Ltd.
Donor‐Functionalised Expanded Ring N‐Heterocyclic Carbenes: Highly Effective Ligands in Ir‐Catalysed Transfer Hydrogenation
Authors: Binobaid Abeer , Iglesias Manuel , Beetstra Dirk , Dervisi Athanasia , Fallis Ian , Cavell Kingsley J.
Published: October 2010

The performances of a number of RhI and IrI complexes of type [M(NHC)(COD)Cl] in the transfer hydrogenation of ketones were tested under a variety of reaction conditions, and with a variety of substrates, allowing comparison of Rh‐ and Ir‐NHC complexes, and also comparison of the influence of the NHC ligand on catalytic performance. Notably, of the RhI and IrI complexes with symmetrically substituted NHCs only those bearing cyclohexyl substituents were active, with RhI complexes of saturated 5‐, 6‐ and 7‐NHCs with N‐Mes substituents, [Rh(5,6,7‐Mes)(COD)Cl], showing no activity in transfer hydrogenation under the test conditions. RhI and IrI complexes of unsymmetrical o‐methoxyphenyl donor‐functionalised NHCs (df‐NHC) with differing carbene ring sizes were also tested in transfer hydrogenations, with the RhI complexes displaying no catalytic activity. However, the corresponding df‐NHC IrI complexes were found to be extremely effective catalysts. Catalyst tests also demonstrated the excellent stability of these complexes.
Pneumatic handling of droplets on‐demand on a microfluidic device for seamless processing of reaction and electrophoretic separation
Authors: Kaneda Shohei , Ono Koichi , Fukuba Tatsuhiro , Nojima Takahiko , Yamamoto Takatoki , Fujii Teruo
Published: October 2010

Sequential operations of pre‐separation reaction process by picoliter droplets and following electrophoretic separation process were realized in a single microfluidic device with pneumatic handling of liquid. The developed device consists of a fluidic chip made of PDMS, an electrode substrate, and a temperature control substrate on which thin film heater/sensor structures are fabricated. Liquid handling, including introduction of liquid samples, droplet generation, and merging of droplets, was implemented by pneumatic manipulation through microcapillary vent structures, allowing air to pass and stop liquid flow. Since the pneumatic manipulations are conducted in a fully automated manner by using a programmable air pressure control system, the user simply has to load liquid samples on each liquid port of the device. Droplets of 420 pL were generated with an accuracy of ±2 pL by applying droplet generation pressure in the range of 40–100 kPa. As a demonstration, a binding reaction of a 15mer ssDNA with a peptide nucleic acid oligomer used as an oligoprobe followed by denaturing electrophoresis to discriminate a single‐base substitution was performed within 1.5 min. By exploiting the droplet‐on‐demand capability of the device, the influence of various factors, such as reaction time, mixing ratio and droplet configurations on the ssDNA‐peptide nucleic acid binding reaction in the droplet‐based process, was studied toward realization of a rapid detection method to discriminate rapid single‐base substitution.
Microchip electroseparation of proteins using lipid‐based nanoparticles
Authors: Ohlsson Pelle , Ordeig Olga , Nilsson Christian , Harwigsson Ian , Kutter Jörg P. , Nilsson Staffan
Published: October 2010

Porous liquid crystalline lipid‐based nanoparticles are shown here to enable protein analysis in microchip electroseparation by reducing sample adsorption. Additionally, higher stability and reproducibility of the separations were observed. The method was tested by separating green fluorescent protein (GFP) in hot embossed cyclic olefin polymer microchips with integrated fiber grooves for LIF detection. The sample adsorption was indirectly quantified by measuring the height, width and asymmetry of the separation peaks for various concentrations of nanoparticles in the sample and background electrolyte. Without nanoparticles, electropherograms displayed typical signs of extensive adsorption to the channel walls, with low, broad tailing peaks. Higher, narrower more symmetric peaks were generated when 0.5–10% nanoparticles were added, showing a dramatic reduction of sample adsorption. The current through the separation channel decreased with nanoparticle concentration, reducing to half its value when the nanoparticle concentration was increased from 0.5 to 4%. Addition of nanoparticles enabled separations that were otherwise hindered by extensive adsorption, e.g. separation of GFP mutants differing by only one amino acid. It was also observed that increasing the nanoparticle concentration increased the number of impurities that could be resolved in a GFP sample. This indicates that the adsorption is further reduced, and/or that the nanoparticles provide an interacting pseudostationary phase for electrochromatography.
Novel shape and placement definitions with retention modeling for solid microfabricated pillar columns for CEC and HPLC
Authors: Sukas Sertan , Desmet Gert , Gardeniers Han J. G. E.
Published: October 2010

A novel design approach for optimizing the shape of microfabricated pillar columns for LC is presented. 2‐D flow simulations are performed with a focus on electrokinetically driven flow, in order to evaluate the performance of the new method. The proposed foil shape is compared with geometrical shapes known from the literature, for various arrangements. It yields a much more uniform velocity field distribution and a decrease in plate height values up to 25%. In addition to shape optimization, a new method for spatial arrangement of structures is presented. With the aim of conserving the hydrodynamic balance, the axial spacing of the pillars is adjusted according to the proposed equivalent width approach. When compared with a fixed interpillar spacing in all directions, it increases the flow uniformity and results in an 18% lower plate height. A new direct simulation approach is implemented to model both flow field and retention for solid microfabricated pillar structures in the 2‐D domain. This model, which defines retention as inward/outward fluxes through the wall surfaces as first order reactions, enables monitoring of the time‐dependent process and an evaluation of the parameters affecting performance. The meaning of the obtained results in a practical setting, with limitations in photolithography and microfabrication, will be highlighted.
A novel type of angle steel buckling‐restrained brace: Cyclic behavior and failure mechanism
Authors: Zhao Junxian , Wu Bin , Ou Jinping
Published: October 2010

A novel type of angle steel buckling‐restrained brace (ABRB) has been developed for easier control on initial geometric imperfection in the core, more design flexibility in the buckling restraining mechanism and easier assembly work. The steel core is composed of four angle steels to form a non‐welded cruciform shape restrained by two external angle steels, which are welded longitudinally to form an external tube. Component test was conducted on seven ABRB specimens under uniaxial quasi‐static cyclic loading. The test results reveal that the consistency between the actual and design behavior of ABRB can be well achieved without the effect of weld in the core. The ABRBs with proper details exhibited stable cyclic behavior and satisfactory cumulative plastic ductility capacity, so that they can serve as effective hysteretic dampers. However, compression–flexure failure at the steel core projection was found to be the primary failure mode for the ABRBs with hinge connections even though the cross‐section of the core projection was reinforced two times that of the yielding segment. The failure mechanism is further discussed by investigating the Nu– Mu correlation curve. It is found that the bending moment response developed in the core projection induced by end rotation was the main cause for such a failure mode, and it is suggested that core projection should be kept within elastic stage under the possible maximum axial load and bending moment response. Copyright © 2010 John Wiley & Sons, Ltd.
Developmental changes in children's inductive inferences for biological concepts: implications for the development of essentialist beliefs
Authors: Farrar M. Jeffrey , Boyer‐Pennington Michelle
Published: October 2010

We examined developmental changes in children's inductive inferences about biological concepts as a function of knowledge of properties and concepts. Specifically, 4‐ to 5‐year‐olds and 9‐ to 10‐year‐olds were taught either familiar or unfamiliar internal, external, or functional properties about known and unknown target animals. Children were asked to infer whether each of four probes, varying in categorical and perceptual similarity to the target, also shared that property. Overall, children made more inferences for known concepts and familiar properties. Older children were more likely to use categorical than perceptual information when making inferences about internal and functional properties of known concepts; however, younger children, in general, made no distinction for property type, and they weighted categorical and perceptual information similarly. Both age groups utilized appearance when making inferences about external properties. Results are discussed in terms of developmental changes in children's appreciation of essentialism. Copyright © 2010 John Wiley & Sons, Ltd.
Word learning from videos: more evidence from 2‐year‐olds
Authors: Allen Rebekah , Scofield Jason
Published: October 2010

Young children are frequently exposed to examples of screen media like videos. The current studies asked whether videos would support word learning and whether word learning from videos might resemble word learning from a live speaker. In Study 1, 2‐year‐olds saw a video of a target image being labelled with a novel word and were later asked to point to and name the image and its live counterpart. Study 2 was similar except that 2‐year‐olds were asked to solve video and live versions of the disambiguation task (i.e. to point to and name a distracter image and its live counterpart). Results showed that 2‐year‐olds learned and disambiguated words from video (as measured by both pointing and naming) and that learning was similar on the video and live versions of each task. These results have important implications for theories of word learning and for the viability of video as a source for young children's word learning. Copyright © 2010 John Wiley & Sons, Ltd.
The big picture: An overview
Authors: Hom Willard C.
Published: October 2010

A system office for community college institutional research manages five basic assets to fill a role in higher education policy that serves both the individual community colleges in a state and the general public.
A fast empirical GAFF compatible partial atomic charge assignment scheme for modeling interactions of small molecules with biomolecular targets
Authors: Mukherjee Goutam , Patra Niladri , Barua Poranjyoti , Jayaram B.
Published: October 2010

We report here a new and fast approach [Transferable Partial Atomic Charge Model (TPACM4)—upto four bonds] for deriving the partial atomic charges of small molecules for use in protein/DNA‐ligand docking and scoring. We have created a look‐up table of 5302 atom types to cover the chemical space of C, H, O, N, S, P, F, Cl, and Br atoms in small molecules together with their quantum mechanical RESP fit charges. The atom types defined span diverse plausible chemical environments of each atom in a molecule. The partial charge on any atom in a given molecule is then assigned by a reference to the look‐up table. We tested the sensitivity of the TPACM4 partial charges in estimates of hydrogen bond dimers energies, solvation free energies and protein‐ligand binding free energies. An average error ±1.11 kcal/mol and a correlation coefficient of 0.90 is obtained in the calculated protein‐ligand binding free energies vis‐à‐vis an RMS error of ±1.02 kcal/mol and a correlation coefficient of 0.92 obtained with RESP fit charges in comparison to experiment. Similar accuracies are realized in predictions of hydrogen bond energies and solvation free energies of small molecules. For a molecule containing 50–55 atoms, the method takes on the order of milliseconds on a single processor machine to assign partial atomic charges. The TPACM4 programme has been web‐enabled and made freely accessible athttp://www.scfbio‐iitd.res.in/software/drugdesign/charge.jsp. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2011.
The gametogenic cycle of Leguminaia whaetleyi (Lea, 1862) in lake Gölbaşı, Turkey (Bivalvia: Unionidae)
Authors: Çek Şehriban , ŞerefliŞan Hülya
Published: October 2010

The gonadal structure and cycle of the Leguminaia whaetleyi is described for the first time indicating that 5% of this species is simultaneous hermaphrodite. A total of 420 individuals were collected in monthly samples from October 2008 to September 2009 in Gölbaşı Lake, Turkey. Calculation of the condition index and histological examination of the gonads showed that gametogenesis began in January. Spawning occurred between May and August with one maximum peak in July. Annual maximum oocytes size peaked in July. The population consisted of simultaneous hermaphrodite individuals. Sex ratio of L. whaetleyi was significantly different from the expected 1:1 ratio (P<0.05), and also female biased sex ratio was recorded. In hermaphrodite specimens, male and female follicles were mixed in the visceral mass but can be clearly distinguished by light microscopy study. L. whaetleyi appears to be a dioecious species in which 25 specimens were simultaneous hermaphrodite and under certain environmental conditions may be capable of self‐fertilization. This suggests that detailed studies on sex ratio of L. whaetleyi may be helpful in understanding unionid phylogeny. J. Exp. Zool. 315:30–40, 2011. © 2010 Wiley‐Liss, Inc.
Viscosimetric detection in size‐exclusion chromatography (SEC/GPC): The Goldwasser method and beyond
Authors: Castignolles Patrice , Gaborieau Marianne
Published: October 2010

Size‐exclusion chromatography (SEC or GPC) is the most widely used separation method to characterize polymers. The high level of complexity of most polymeric materials necessitates the use of not only concentration‐sensitive detection but also structure‐sensitive detection. Viscometry is usually used in conjunction with a concentration‐sensitive detector and universal calibration to determine molecular weights of polymers. Goldwasser proposed to use a viscometer as a single detector to determine number‐average molecular weights, Mn (ACS Symposium Series, 521, 143). The method is particularly of interest when concentration‐sensitive detection is not available, because the sample is isorefractive or not UV‐absorbing, or because composition is not constant (copolymers). It has known very little applications so far. It actually does not only allow determining Mn, but also the number hydrodynamic volume distribution. This opens a wider range of applications for the Goldwasser method. Size‐exclusion chromatography only yields inaccurate molecular weight distributions for some complex branched polymers. Hydrodynamic volume distributions have then a strong potential for comparative studies owing to their far higher accuracy. Our experimental tests highlight the fact that the method is highly sensitive to noise and careful optimization of the injection concentration is needed, but number distribution can be obtained as well as Mn.
2‐D chromatography applied to the study of block copolymers synthesized by nitroxide‐mediated controlled free‐radical seeded emulsion polymerization
Authors: Moyses Stephan , Ness Jason , Papakonstantopoulos George
Published: October 2010

2‐D chromatography with gradient polymer elution chromatography in the first dimension was used to characterize a series of block copolymers prepared by nitroxide‐mediated controlled free‐radical seeded emulsion polymerization. The data provide a detailed picture of the different populations generated during the successive stages of the reaction. In particular, deviations from ideal conditions, such as an exothermic temperature spike, are obvious from the 2‐D chromatogram, and its interpretation provides unique insight into the reaction mechanisms. Finally, atomic force microscopy images obtained on films cast from copolymer solutions evidence the relationship between polymer microstructure and film morphology.
Potential of a metal–organic framework as a new material for solid‐phase extraction of pesticides from lettuce (Lactuca sativa), with analysis by gas chromatography‐mass spectrometry
Authors: Barreto Alysson S. , da Silva Rogério Luiz , dos Santos Silva Silvia Caroline G. , Rodrigues Marcelo O. , de Simone Carlos A. , de Sá Gilberto F. , Júnior Severino A. , Navickiene Sandro , de Mesquita Maria Eliane
Published: October 2010

The metal–organic framework ∞[(La0.9Eu0.1)2(DPA)3(H2O)3] was tested for extraction of pyrimicarb, procymidone, malathion, methyl parathion and α‐ and β‐endosulfan from lettuce, with analysis using GC/MS in SIM mode. Experiments were carried out in triplicate at two fortification levels (0.1 and 0.5 mg/kg), and resulted in recoveries in the range of 78–107%, with RSD values between 1.6 and 8.0% for ∞[(La0.9Eu0.1)2(DPA)3(H2O)3] sorbent. Detection and quantification limits ranged from 0.02 to 0.05 mg/kg and from 0.05 to 0.10 mg/kg, respectively, for the different pesticides studied. The method developed was linear over the range tested (0.05–10.0 μg/mL), with correlation coefficients ranging from 0.9990 to 0.9997. Comparison between ∞[(La0.9Eu0.1)2(DPA)3(H2O)3] and conventional sorbent (silica gel) showed better performance of the ∞[(La0.9Eu0.1)2(DPA)3(H2O)3] polymeric sorbent for all pesticides tested.
Endothelin und Endothelin‐Rezeptorantagonisten. Wirkungen, Nebenwirkungen und Interaktionen
Authors: Dahse Anna‐Judith , Nieber Karen
Published: October 2010

Die Substanzklasse der ET‐Rezeptorantagonisten hat die Therapiemöglichkeiten der PAH erweitert. Die therapieresistente Hypertonie scheint dagegen keine viel versprechende Indikation zu sein. Ein Problem stellt die Lebertoxizität dar. Obwohl bei den selektiven Antagonisten geringer ausgeprägt, sind regelmäßige Kontrolluntersuchungen erforderlich. Ebenfalls nicht ausreichend geklärt ist die Embryotoxizität. Deshalb muss eine Schwangerschaft vor und während der Behandlung mit ET‐Rezeptorantagonisten unbedingt ausgeschlossen werden. Es bleibt abzuwarten, wann weitere ET‐Rezeptorantagonisten mit verbesserter Nutzen‐Risiko‐Relation auf den Markt kommen. Begonnen hat auch die Entwicklung von selektiven ETB‐Rezeptoragonisten. Die intravenös applizierbare Substanz SPI 1620 befindet sich derzeit in Phase‐I‐ und Phase‐II‐Studien als Adjuvans zur Chemotherapie. Auch hier wird die Zukunft zeigen, wie effektiv diese Substanzen sind.
Molekulare Mechanismen der Endothelin‐Rezeptorerkennung. Ursachen von Selektivität, Aktivierung und Inhibierung
Authors: Lättig Jens , Krause Gerd
Published: October 2010

Die Kombination umfangreicher, experimenteller Daten aus biochemischen und strukturbiologischen Experimenten mit theoretischen Modellen und Simulationen ermöglichte die Charakterisierung der molekularen Details für Rezeptorselektivität und Subtypspezifität in den Endothelinrezeptoren ETA und ETB. Anfängliche Betrachtungen der Wechselwirkungen von natürlichen Peptidliganden und deren synthetischen Derivaten in beiden Endothelinrezeptor‐Subtypen resultierten in weiteren Erkenntnissen hinsichtlich Aktivierung und Hemmung von ETA und ETB. Weitergehende strukturelle Vergleiche dieser Liganden mit synthetischen Endothelinrezeptor‐Antagonisten (Sentane) sind konsistent zu den bestehenden Ligand‐Rezeptor‐Modellen. Folglich werden die so gewonnenen Erkenntnisse bezüglich Rezeptorselektivität, Subtypspezifität, Aktivierung und Inhibierung in zukünftigen Studien und in der Entwicklung neuer Liganden für ETA und ETB von Nutzen sein.
Praktisches Management der pulmonal arteriellen Hypertonie. Therapie nach aktuellen Leitlinien
Authors: Pabst Stefan , Hammerstingl Christoph , Nickenig Georg , Skowasch Dirk
Published: October 2010

Die pulmonal arterielle Hypertonie (PAH) ist eine Erkrankung mit komplexer Symptomatik, Ätiologie und Pathophysiologie. Sie ist nicht heilbar und die Überlebenszeit bei unzureichender Therapie ähnelt dem einiger maligner Erkrankungen. Durch eine zielgerichtete Diagnostik und sich anschließende spezifische Therapie können das Überleben und die Lebensqualität deutlich gesteigert werden. Die Studienlage bezüglich einer adäquaten, stadienabhängigen Therapie hat sich in den letzten Jahren erheblich verbessert.
Pulmonale Hypertonie aus Patientensicht. Hilfe durch Selbsthilfegruppen
Authors: Kopp Bruno
Published: October 2010

Der gemeinnützige Selbsthilfeverein pulmonale hypertonie e.v. (ph e.v.) möchte an pulmonaler Hypertonie erkrankten Patienten und deren Angehörigen in ihrem persönlichen Schicksal helfen. Der Verein gibt Informationen über Möglichkeiten der Diagnostik und der Therapie weiter und vermittelt Kontakte zu spezialisierten Ärzten.