bluuebunny/crossref_metadata_2025 huggingface dataset:
Steric Modulation of Coordination Number and Reactivity in the Synthesis of Lanthanoid(III) Formamidinates
Authors: Cole Marcus L. , Deacon Glen B. , Forsyth Craig M. , Junk Peter C. , Konstas Kristina , Wang Jun
Published: September 2007

Reactions of a range of the readily prepared and sterically tunable N,N′‐bis(aryl)formamidines with lanthanoid metals and bis(pentafluorophenyl)mercury (Hg(C6F5)2) in THF have given an extensive series of tris(formamidinato)lanthanoid(III) complexes, [Ln(Form)3(thf)n], namely [La(o‐TolForm)3(thf)2], [Er(o‐TolForm)3(thf)], [La(XylForm)3(thf)], [Sm(XylForm)3], [Ln(MesForm)3] (Ln=La, Nd, Sm and Yb), [Ln(EtForm)3] (Ln=La, Nd, Sm, Ho and Yb), and [Ln(o‐PhPhForm)3] (Ln=La, Nd, Sm and Er). [For an explanation of the N,N′‐bis(aryl)formamidinate abbreviations used see Scheme 1.] Analogous attempts to prepare [Yb(o‐TolForm)3] by this method invariably yielded [{Yb(o‐TolForm)2(μ‐OH)(thf)}2], but [Yb(o‐TolForm)3] was isolated from a metathesis synthesis. X‐ray crystal structures show exclusively N,N′‐chelation of the Form ligands and a gradation in coordination number with Ln3+ size and with Form ligand bulk. The largest ligands, MesForm, EtForm and o‐PhPhForm give solely homoleptic complexes, the first two being six‐coordinate, the last having an η1‐π‐ArLn interaction. Reaction of lanthanoid elements and Hg(C6F5)2 with the still bulkier DippFormH in THF resulted in CF activation and formation of [Ln(DippForm)2F(thf)] (Ln=La, Ce, Nd, Sm and Tm) complexes, and o‐HC6F4O(CH2)4DippForm in which the formamidine is functionalised by a ring‐opened THF that has trapped tetrafluorobenzyne. Analogous reactions between Ln metals, Hg(o‐HC6F4)2 and DippFormH yielded [Ln(DippForm)2F(thf)] (Ln=La, Sm and Nd) and 3,4,5‐F3C6H2O(CH2)4DippForm. X‐ray crystal structures of the heteroleptic fluorides show six‐coordinate monomers with two chelating DippForm ligands and cisoid fluoride and THF ligands in a trigonal prismatic array. The organometallic species [Ln(DippForm)2(CCPh)(thf)] (Ln=Nd or Sm) are obtained from reaction of Nd metal, bis(phenylethynyl)mercury (Hg(CCPh)2) and DippFormH, and the oxidation of [Sm(DippForm)2(thf)2] with Hg(CCPh)2, respectively. The monomeric, six‐coordinate, cisoid [Ln(DippForm)2(CCPh)(thf)] complexes have trigonal prismatic geometries and rare (for Ln) terminal CCPh groups with contrasting LnCC angles (Ln=Nd, 170.9(4)°; Ln=Sm, 142.9(7)°). Their formation lends support to the view that [Ln(DippForm)2F(thf)] complexes arise from oxidative formation and CF activation of [Ln(DippForm)2(C6F5)] intermediates.
Demonstration of spontaneous chiral symmetry breaking in asymmetric Mannich and Aldol reactions
Authors: Mauksch Michael , Tsogoeva Svetlana B. , Wei Shengwei , Martynova Irina M.
Published: September 2007

Spontaneous symmetry breaking in reactive systems, known as a rare physical phenomenon and for the Soai autocatalytic irreversible reaction, might in principle also occur in other, more common asymmetric reactions when the chiral product is capable to promote its formation and an element of “nonlinearity” is involved in the reaction scheme. Such phenomena are long sought after in chemistry as a possible explanation for the biological homochirality of biomolecules. We have investigated homogeneous organic stereoselective Mannich and Aldol reactions, in which the product is capable to form H‐bridged complexes with the prochiral educt, and found by applying NMR spectroscopy, HPLC analysis, and optical rotation measurements 0.3–50.8% of random product enantiomeric excess under essentially achiral reaction conditions. These findings imply a hitherto overlooked mechanism for spontaneous symmetry breaking and, hence, a novel approach to the problem of absolute asymmetric synthesis and could have also potential significance for the conundrum of homochirality. Chirality, 2007. © 2007 Wiley‐Liss, Inc.
Emission detected circular dichroism from long‐lived excited states: Application to chiral Eu(III) systems
Authors: Muller Françoise C. , Muller Gilles , Riehl James P.
Published: September 2007

The measurement of the difference in intensity of luminescence following excitation with left and right circularly polarized light for racemic terdentate Eu(III) complexes with 2,6‐pyridine dicarboxylic acids perturbed by the addition of (+)‐dimethyltartrate and for tris chiral complexes of Eu(III) with (R,R)‐N,N′‐bis(1‐phenylethyl)‐2,6‐pyridine‐dicarboxamide are presented. The experimental technique used for these measurements is identical in design to fluorescence detected circular dichroism spectroscopy, but is referred to in this manuscript as emission detected circular dichroism (EDCD) because of the long lifetime of the Eu(III) excited state requiring specialized instrumentation. These measurements required relatively slow modulation of the incident circular polarization, which was accomplished with a liquid crystal polarizer. The results are compared with conventional CD measurements, and additional characteristics and potential applications of EDCD are presented. Chirality, 2007. © 2007 Wiley‐Liss, Inc.
The Fe2+‐Mediated Decomposition, PfATP6 Binding, and Antimalarial Activities of Artemisone and Other Artemisinins: The Unlikelihood of C‐Centered Radicals as Bioactive Intermediates
Authors: Haynes Richard K. , Chan Wing Chi , Lung Chung‐Man , Uhlemann Anne‐Catrin , Eckstein Ursula , Taramelli Donatella , Parapini Silvia , Monti Diego , Krishna Sanjeev
Published: September 2007

The results of Fe2+‐induced decomposition of the clinically used artemisinins, artemisone, other aminoartemisinins, 10‐deoxoartemisinin, and the 4‐fluorophenyl derivative have been compared with their antimalarial activities and their ability to inhibit the parasite SERCA PfATP6. The clinical artemisinins and artemisone decompose under aqueous conditions to give mixtures of C radical marker products, carbonyl compounds, and reduction products. The 4‐fluorophenyl derivative and aminoartemisinins tend to be inert to aqueous iron(II) sulfate and anhydrous iron(II) acetate. Anhydrous iron(II) bromide enhances formation of the carbonyl compounds and provides a deoxyglycal from DHA and enamines from the aminoartemisinins. Ascorbic acid (AA) accelerates the aqueous Fe2+‐mediated decompositions, but does not alter product distribution. 4‐Oxo‐TEMPO intercepts C radicals from a mixture of an antimalaria‐active trioxolane, 10‐deoxoartemisinin, and anhydrous iron(II) acetate to give trapped products in 73 % yield from the trioxolane, and 3 % from the artemisinin. Artemisone provides a trapped product in 10 % yield. Thus, in line with its structural rigidity, only the trioxolane provides a C radical eminently suited for intermolecular trapping. In contrast, the structural flexibility of the C radicals from the artemisinins allows facile extrusion of Fe2+ and collapse to benign isomerization products. The propensity towards the formation of radical marker products and intermolecular radical trapping have no relationship with the in vitro antimalarial activities of the artemisinins and trioxolane. Desferrioxamine (DFO) attenuates inhibition of PfATP6 by, and antagonizes antimalarial activity of, the aqueous Fe2+‐susceptible artemisinins, but has no overt effect on the aqueous Fe2+‐inert artemisinins. It is concluded that the C radicals cannot be responsible for antimalarial activity and that the Fe2+‐susceptible artemisinins may be competitively decomposed in aqueous extra‐ and intracellular compartments by labile Fe2+, resulting in some attenuation of their antimalarial activities. Interpretations of the roles of DFO and AA in modulating antimalarial activities of the artemisinins, and a comparison with antimalarial properties of simple hydroperoxides and their behavior towards thapsigargin‐sensitive SERCA ATPases are presented. The general basis for the exceptional antimalarial activities of artemisinins in relation to the intrinsic activity of the peroxide within the uniquely stressed environment of the malaria parasite is thereby adumbrated.
Amelioration of Hyperglycemia and Metabolic Syndromes in Type 2 Diabetic KKAy Mice by Poly(γ‐glutamic acid)oxovanadium(IV) Complex
Authors: Karmaker Subarna , Saha Tapan K. , Yoshikawa Yutaka , Sakurai Hiromu
Published: September 2007

Recently, we found that poly(γ‐glutamic acid)oxovanadium(IV) complex (VO(γ‐pga)) exhibits a potent antidiabetic activity in streptozotocin (STZ)‐induced type 1 diabetic mice. This result prompted us to examine its ability to treat the type 2 diabetic model KKAy mice with insulin resistance. We studied the in vivo antidiabetic activity of VO(γ‐pga), compared with that of vanadium(IV) oxide sulfate (VS) as control. Both compounds were orally administered at doses of 5–10 mg (0.1–0.2 mmol) V kg−1 body mass to the KKAy mice for 30 days. VO(γ‐pga) normalized the hyperglycemia within 21 days, whereas VS lowered the blood glucose concentration only by a small degree. In addition, the glucose intolerance, HbA1c level, hyperinsulinemia, hypercholesterolemia, and hyperleptinemia were significantly improved in VO(γ‐pga)‐treated KKAy mice compared with those treated with VS. Based on these observations, VO(γ‐pga) is proposed to be the first orally active oxovanadium(IV)‐polymer complex for the efficacious treatment of not only type 2 diabetes but also metabolic syndrome in animals.
Nuclear magnetic moments from NMR spectra—Experimental gas phase studies and nuclear shielding calculations
Authors: Jackowski Karol , Jaszuński Michał
Published: September 2007

NMR spectra of gaseous compounds and quantum chemical calculations are combined to determine new accurate values of magnetic dipole moments for a series of nuclei. We have analyzed shielding constants, resonance frequencies, and nuclear magnetic moments for a group of simple molecules. The chemical shifts and resonance frequencies are measured at 300 K and extrapolated to the zero‐density limit in order to remove all the intermolecular effects from the experimental parameters. The absolute shielding constants in the studied molecules are obtained from ab initio calculations. Assuming the proton magnetic moment as the reference, we determine the nuclear magnetic moments of 13C, 14N, 15N, 17O, 19F, 29Si, 31P, 33S, and 73Ge. The new nuclear magnetic moments are consistent with the experimental NMR parameters, and using these new values one can for the first time predict successfully the shielding constant of a nucleus in a molecule when the corresponding resonance frequency is known. © 2007 Wiley Periodicals, Inc. Concepts Magn Reson Part A 30A: 246–260, 2007.
Using PGSE NMR for chemical mixture analysis: Quantitative aspects
Authors: Antalek Brian
Published: September 2007

Pulsed gradient spin echo NMR coupled with a data processing approach such as direct exponential curve resolution algorithm may be used to resolve individual components in a mixture. Differences in the diffusivities of the components lead to differences in their signal decay behavior in the experiment and allow for pure component spectra to be resolved. Because the experiment is echo‐based, differences in the relaxation behavior of the nuclei within the various components lead to nonquantitative spectra. As a consequence it is rarely used to directly determine the levels of the components quantitatively. This article explores the effects of signal loss in the PGSE NMR experiment because of relaxation and describes an extrapolation method to ultimately obtain quantitative pure component spectra from mixtures. Examples of surface‐modified nanoparticles are presented. © 2007 Wiley Periodicals, Inc.Concepts Magn Reson Part A 30A: 219–235, 2007.
Treatment outcomes of small cell carcinoma of the prostate
Authors: Spiess Philippe E. , Pettaway Curtis A. , Vakar‐Lopez Funda , Kassouf Wassim , Wang Xuemei , Busby Joseph E. , Do Kim‐Anh , Davuluri Rajayogesh , Tannir Nizar M.
Published: September 2007

BACKGROUND.

The current study was conducted to determine the clinical characteristics and prognostic features associated with prostatic small cell carcinoma (SCC).

METHODS.

Between January 1985 and May 2005, 83 patients with SCC of the prostate were identified. Univariate and multivariate Cox proportional hazards modeling were used to assess the prognostic significance of the clinical parameters associated with disease‐specific outcomes.

RESULTS.

Twenty‐one patients had no evidence of distant metastasis at the time of the diagnosis of SCC, with the remaining patients demonstrating radiologic or biopsy‐proven evidence of metastatic disease. Compared with patients with metastases, patients without metastases at the time of diagnosis were older (P = .001) and had a lower serum lactate dehydrogenase (LDH) level at the time of diagnosis (P = .002). On multivariate analysis, an elevated serum LDH level and low serum albumin at the time of SCC diagnosis was found to be predictive of inferior progression‐free survival (P = .02 and P = .008, respectively) and inferior disease‐specific survival (DSS) (P = .02 and P = .01, respectively). At the time of last follow‐up, 72 patients (87%) had died of disease, with a median DSS duration of 13.1 months (range, 10.7–17.1 months). There was a statistically significant difference noted with regard to the median DSS of patients with nonmetastatic versus those with metastatic SCC (17.7 months [95% confidence interval (95% CI), 12.1–39.2 months] vs 12.5 months [95% CI, 8.1–16.1 months], respectively; P = .03).

CONCLUSIONS.

SCC of the prostate is a highly aggressive tumor, with serum LDH and albumin levels at the time of diagnosis believed to be predictive of disease‐related outcomes. Although palliative, current systemic therapy does not result in cure and does not provide long‐term survival for patients with metastases. For patients with nonmetastatic disease, a strategy utilizing systemic and local therapies should be evaluated further. Cancer 2007. © 2007 American Cancer Society.
Trends in childhood leukemia mortality in Brazil and correlation with social inequalities
Authors: Ribeiro Karina B. , Lopes Luiz F. , de Camargo Beatriz
Published: September 2007

BACKGROUND.

Mortality from childhood leukemia has declined substantially in developed countries but less markedly in the developing world. This study was designed to describe mortality trends in childhood leukemia and the impact of social inequalities on these trends in Brazil from 1980 to 2002.

METHODS.

Cancer mortality data by cause and estimates of resident population stratified by age and sex were obtained from the Brazilian Mortality Information System (SIM) for the years 1980 to 2002. Age‐standardized (ages 0‐19 years) mortality rates were calculated by the direct method using the 1960 world standard population. Trends were modeled using linear regression with 3‐year moving average rates as the dependent variable and with the midpoint of the calendar year interval (1991) as the independent variable. The Index of Social Exclusion was used to classify the 27 Brazilian states. Pearson correlation was used to describe the correlation between social exclusion and variations in mortality in each state.

RESULTS.

Age‐standardized mortality rates for boys decreased from 2.05 per 100,000 habitants in 1984 to 1.44 100,000 habitants in 1995, whereas the observed corresponding decline among girls was from 1.60 per 100,000 habitants in 1986 to 1.14 per 100,000 habitants in 1995. Statistically significant declining trends in mortality rates were observed for boys (adjusted correlation coefficient [r2] = 0.68; P < .001) and girls (adjusted r2 = 0.62; P < .001). Significant negative correlations between social inequality and changes in mortality were noted for boys (r = −0.66; P = .001) and for girls (r = −0.78; P < .001).

CONCLUSIONS.

A consistent decrease in mortality rates from childhood leukemia was noted in Brazil. Higher decreases in mortality were observed in more developed states, possibly reflecting better health care. Cancer 2007. © 2007 American Cancer Society.
Application of high‐order Higdon non‐reflecting boundary conditions to linear shallow water models
Authors: Neta Beny , van Joolen Vince , Dea John R. , Givoli Dan
Published: September 2007

A shallow water model with linear time‐dependent dispersive waves in an unbounded domain is considered. The domain is truncated with artificial boundaries ℬ︁ where a sequence of high‐order non‐reflecting boundary conditions (NRBCs) proposed by Higdon are applied. Methods devised by Givoli and Neta that afford easy implementation of Higdon NRBCs are refined in order to reduce computational expenses. The new refinement makes the
computational effort associated with the boundary treatment quadratic rather than exponential (as in the original scheme) with the order. This allows for implementation of NRBCs of higher orders than previously. A numerical example for a semi‐infinite channel truncated on one side is presented. Finite difference schemes are used throughout. Copyright © 2007 John Wiley & Sons, Ltd.
Global exponential stability for uncertain bidirectional associative memory neural networks with multiple time‐varying delaysviaLMI approach
Authors: Gau Ruey‐Shyan , Hsieh Jer‐Guang , Lien Chang‐Hua
Published: September 2007

The global exponential stability for uncertain delayed bidirectional associative memory neural networks (DBAMNN) with multiple time‐varying delays is considered in this paper. Delay‐dependent criteria are proposed to guarantee the robust stability of DBAMNNvialinear matrix inequality approach. Two classes of system uncertainties are investigated in this paper. Some numerical examples are given to illustrate the effectiveness of our results. From the numerical simulations, significant improvement over the recent results can be observed. Copyright © 2007 John Wiley & Sons, Ltd.
Baukonstruktionen mit Mauerwerk – Überblick zu aktuellen technischen Entwicklungen
Authors: Fehling Ekkehard , Stürz Jochen
Published: September 2007

Die ständig wachsenden Anforderungen an den Baustoff Mauerwerk erfordern eine stetige Weiterentwicklung seiner Eigenschaften. So soll Mauerwerk heute zuverlässig und dauerhaft Wärme‐ und Schallschutz bieten, das Errichten der Wände auf der Baustelle soll möglichst rationell durchzuführen sein und die Standsicherheit muss auch für die durch neue Normen erhöhten Wind‐ und Erdbebenbeanspruchungen gewährleistet werden können. Hierfür ist ein umfangreiches und grundlegendes Verständnis des Tragverhaltens von Mauerwerk unter Schubbeanspruchung notwendig, welches in dem europäischen Forschungsvorhaben ESECMaSE umfangreich untersucht werden soll.
Praxistipps zur Ausführung von Mauerwerk
Authors: Schubert Peter
Published: September 2007

Eine wesentliche Voraussetzung für die normgerechte Standsicherheit und Gebrauchsfähigkeit von Mauerwerk ist deren regel‐ und sachgerechte Ausführung. Wichtige Ausführungsregeln betreffen vor allem das Überbindemaß, die Ausführung von Lager‐ und Stoßfugen sowie die Maßtoleranzen der Bauteile, besonders die Ebenheitsanforderungen an die Rohbauoberflächen. Im Beitrag werden der Einfluss dieser Ausführungsparameter auf die Mauerwerkeigenschaften, die entsprechenden Bestimmungen in den Technischen Regelwerken sowie die Frage nach hinzunehmenden Abweichungen von den Anforderungen behandelt.
Chancen für Nachhaltigkeit und Energieeffizienz in Deutschland
Authors: Hegner Hans‐Dieter
Published: September 2007

Die Bewertung des Beitrages von Einzelbauwerken zu einer nachhaltigen Entwicklung führen zur Forderung der Entwicklung eines Gesamtsystems zur Beschreibung und Beurteilung von Gebäuden einschließlich des Grundstücks. Ansätze für ein solches System gibt es, selbst Normungsbemühungen, aber eine standardisierte Regel lässt auf sich warten. Ungeachtet dessen bieten sich international Zertifizierungssysteme an, um die Nachhaltigkeit von Gebäuden festzustellen. Vielfach wird unter nachhaltigem Bauen insbesondere energieeffizientes Bauen verstanden. Dies ist nicht generell falsch. Aber Energieeffizienz ist nur ein Teil der Nachhaltigkeit. Dieser Teil ist jedoch mittlerweile gut geregelt. Mit der Umsetzung der EG‐Richtlinie 2002/91/EG über die Gesamtenergieeffizienz von Gebäuden in nationales Recht wurde in Deutschland das Energieeinsparrecht (Energieeinspargesetz, Energieeinsparverordnung) umfassend novelliert. Das Zweite Gesetz zur Änderung des Energieeinspargesetzes ist am 08.09.2005 in Kraft getreten. Auf dieser Grundlage hat die Bundesregierung die Energieeinsparverordnung 2007 (EnEV 2007) am 24.07.2007 endgültig beschlossen. Sie wird voraussichtlich im Oktober 2007 in Kraft treten. Der folgende Beitrag gibt eine Übersicht zu den vorgesehenen neuen Anforderungen beim energiesparenden Bauen und zu den geplanten Anforderungen und Instrumenten des Bundes beim nachhaltigen Bauen.
Synthesis of Flexible Bis‐Intercalating Ruthenium(II) Complexes
Authors: Brodie Craig R. , Aldrich‐Wright Janice R.
Published: September 2007

We report the synthesis, resolution and characterisation of a number of novel ruthenium(II) complexes. Four mononuclear complexes, [Ru(dpq)2(3‐Br‐phen)]2+, [Ru(dpq)2(4‐Cl‐phen)]2+, [Ru(dpq)2(5‐Cl‐phen)]2+and [Ru(dpq)2(phen)]2+were synthesised (dpq = dipyrido[3,2‐d:2′,3′‐f]quinoxaline, phen = 1,10‐phenanthroline, 3‐Br‐phen = 3‐bromo‐1,10‐phenanthroline, 4‐Cl‐phen = 4‐chloro‐1,10‐phenanthroline, 5‐Cl‐phen = 5‐chloro‐1,10‐phenanthroline). These complexes were resolved using the chiral TRISPHAT anion, [tris(tetrachlorocatecholato)phosphate(V)]–. Racemic mononuclear complexes were used in the synthesis of the racemic dinuclear complexes, [{Ru(dpq)2}2μ‐(phen‐n‐SOS‐n‐phen)]4+(SOS = 2‐mercaptoethyl ether,n= 3, 4 or 5). Resolved mononuclear complexes were used to synthesise stereoselectively the ΔΔ‐ and ΛΛ‐enantiomers of their respective dinuclear complexes. All metal complexes were characterised by1H NMR, ESI‐MS, UV/Vis and luminescence spectroscopy. Resolved metal complexes were further characterised using CD spectroscopy and chiral1H NMR titrations.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A Tris‐Cyclometalated Iridium(III) Complex of 2‐(5,5‐Dioxido‐dibenzothiophen‐3‐yl)pyridine: Synthesis, Structural, Redox and Photophysical Properties
Authors: Tavasli Mustafa , Bettington Sylvia , Perepichka Igor F. , Batsanov Andrei S. , Bryce Martin R. , Rothe Carsten , Monkman Andrew P.
Published: September 2007

The first cyclometalated dibenzothiophene S,S‐dioxide derivative, namely [fac‐2‐(5,5‐dioxidodibenzothiophen‐3‐yl)pyridine]iridium(III) (3) has been synthesised in high yield and characterised by X‐ray crystallography, solution electrochemistry, absorption and emission spectroscopy. The Ir atom has a fac‐octahedral coordination with three chelating ligands (A, B and C); each Ir–N bond is in trans position to an Ir–C bond. In cyclic voltammetry experiments in dichloromethane, complex 3 undergoes a reversible metal‐centred IrIII/IrIV oxidation at E1/2ox = +1.04 V vs. Ag/Ag+ reference electrode. Complex 3 exhibits bright green photoluminescence (λmax = 525 nm in toluene) from mixed 3MLCT/3π→π* states with quantum yield (ΦPL) of 0.26 in toluene solution. The phosphorescence emission decay follows first order kinetics, with a lifetime of 4.9 μs. A comparison of complex 3 with analogues 1 and 2, where the dibenzothiophene S,S‐dioxide unit is replaced by 9,9‐dihexylfluorene and N‐hexylcarbazole respectively, establish that the substituent para to the Ir metal atom, i.e. CR2 in 1, NR in 2 and SO2 in 3, has a major influence on the redox and emission properties in this series. Organic light‐emitting diodes (OLEDs) were fabricated by spin‐coating techniques using a polyspirobifluorene copolymer (PSBF) as a host and complex 3 as dopant.In a single‐layer blend configuration ITO/PEDOT:PSS/PSBF:3(8 wt.‐%)/Ba/Al OLEDs showed pale blue/white light emission (CIE coordinates: x = 0.29, y = 0.31) arising from a combination of fluorescence from the host copolymer (λmax = 450 nm) and phosphorescence from 3 (λmax = 530 nm). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Chiral Calix[4]arene‐Based Diphosphites as Ligands in the Asymmetric Hydrogenation of Prochiral Olefins
Authors: Marson Angelica , Freixa Zoraida , Kamer Paul C. J. , van Leeuwen Piet W. N. M.
Published: September 2007

Chiral calixarene‐based diphosphite ligands 3a–d have been obtained via lower‐rim functionalisation of the p‐tert‐butylcalix[4]arene core. High enantiomeric excesses (up to 94 %) and good activities were obtained in the rhodium‐catalyzed asymmetric hydrogenation of prochiral olefins withTADDOL‐containing diphosphites 3c,d. This is the firstexample of chiral calix[4]arene‐modified ligands that induce high enantioselectivity in metal‐catalysed asymmetric reactions.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Voltammetry: An In Situ Tool to Monitor the Health of Ecosystems
Authors: Ma Shufen , Luther George W. , Scarborough Robert W. , Mensinger Michael G.
Published: September 2007

A solid‐state Au/Hg voltammetric microelectrode was used to monitor the development of seasonal anoxia in Delaware coastal bays which have deep holes with stratification. Since fish kills and harmful algal blooms have occurred over the years here, water circulators were installed in October 2003 to improve water quality. We conducted in situ determination of temperature, salinity, pH, dissolved O2 and H2S to document the circulators' function which was evaluated by comparing in situ data obtained before and after their installation. Stratification at both sites was similar in 2004 to that in previous years. Furthermore, the circulators did not oxygenate the water column but did bring some H2S to the surface waters. We found that O2 concentrations in the surface waters and H2S concentrations in the bottom waters were similar in different years. Thus, the H2S conditions were not abated and water quality was still a problem.
Determination of phosphate in seawater by CZE with on‐line transient ITP
Authors: Okamoto Takaaki , Fukushi Keiichi , Takeda Sahori , Wakida Shin‐ichi
Published: September 2007

We developed CZE with indirect UV detection for the determination of phosphate in seawater using transient ITP as an on‐line concentration procedure. The following optimum conditions were established: BGE, 5 mM 2,6‐pyridinedicarboxylic acid (PDC) containing 0.01% hydroxypropylmethylcellulose (HPMC) adjusted to pH 3.5; detection wavelength, 200 nm; vacuum injection period of sample, 3 s (45 nL); terminating ion solution, 500 mM MES adjusted to pH 4.0; vacuum injection period of the terminating ion solution, 30 s (450 nL); applied voltage, 30 kV with the sample inlet side as the cathode. The LOD for phosphate was 16 μg/L ($ \displaystyle {{PO}}_{{4}}^{{{3}} -}$–P) at S/N of 3. The respective values of the RSD of the peak area, peak height, and migration time for phosphate were 2.6, 2.3, and 0.34%. The proposed method was applied to the determination of phosphate in a seawater certified reference material for nutrients, MOOS‐1, distributed by the National Research Council of Canada (NRC). The results were very similar to certified values. The method was also applied to the determination of phosphate in coastal seawaters. The results agreed with those obtained using a conventional spectrophotometric method.
Anisotropic mesh refinement for discontinuous Galerkin methods in two‐dimensional aerodynamic flow simulations
Authors: Leicht Tobias , Hartmann Ralf
Published: September 2007

We derive and implement two types of anisotropic indicators which can be used within an anisotropic refinement algorithm for second but also for higher‐order discontinuous Galerkin discretizations. Although the first type of indicator employs the possible inter‐element discontinuities of the discrete functions, the second type of indicator estimates the approximation error in terms of second but possibly also higher‐order derivatives. We implement a simple extension of these indicators to systems of equations which performs similar to the so‐called metric intersection used to combine the metric information of several solution components and is applicable to higher‐order discretizations as well. The anisotropic indicators are incorporated into an adaptive refinement algorithm which uses state‐of‐the‐art residual‐based or
adjoint‐based indicators for goal‐oriented refinement to select the elements to be refined, whereas the anisotropic indicators determine which anisotropic case the selected elements shall be refined with. We demonstrate the performance of the anisotropic refinement algorithm for sub‐, trans‐ and supersonic, inviscid and viscous compressible flows around a NACA0012 airfoil. Copyright © 2007 John Wiley & Sons, Ltd.
Multi‐method global sensitivity analysis (MMGSA) for modelling floodplain hydrological processes
Authors: Cloke H. L. , Pappenberger F. , Renaud J.‐P.
Published: September 2007

When studying hydrological processes with a numerical model, global sensitivity analysis (GSA) is essential if one is to understand the impact of model parameters and model formulation on results. However, different definitions of sensitivity can lead to a difference in the ranking of importance of the different model factors. Here we combine a fuzzy performance function with different methods of calculating global sensitivity to perform a multi‐method global sensitivity analysis (MMGSA). We use an application of a finite element subsurface flow model (ESTEL‐2D) on a flood inundation event on a floodplain of the River Severn to illustrate this new methodology. We demonstrate the utility of the method for model understanding and show how the prediction of state variables, such as Darcian velocity vectors, can be affected by such a MMGSA. This paper is a first attempt to use GSA with a numerically intensive hydrological model. Copyright © 2007 John Wiley & Sons, Ltd.
Hyporheic and total transient storage in small, sand‐bed streams
Authors: Stofleth John M. , Shields Jr F. Douglas , Fox Garey A.
Published: September 2007

Key processes in stream ecosystems are linked to hydraulic retention, which is the departure of stream flow from ideal ‘plug flow’, and reflects fluid movement through surface and hyporheic storage zones. Most existing information about hyporheic exchange is based on flume studies or field measurements in relatively steep streams with beds coarser than sand. Stream tracer studies may be used to quantify overall hydraulic retention, but disaggregation of surface and hyporheic retention remains difficult. A stream tracer approach was used to compute the rates at which stream water is exchanged with water in storage zones (total storage) in short reaches of two small, sand‐bed streams under free and obstructed flow conditions. Tracer curves were fit to the one‐dimensional transport with inflow storage model OTIS‐P. Networks of piezometers were used to measure specific discharge between the stream and the groundwater. In the sand‐bed streams studied, parameters describing total retention were in the upper 50% of data compiled from the literature, most of which represented streams with beds coarser than sand. However, hyporheic storage was an insignificant component of total hydraulic retention, representing only 0·01–0·49% of total exchange, and this fraction did not increase after installation of flow obstructions. Total retention did not vary systematically with bed material size, but increased 50–100% following flow obstruction. Removal of roughness elements, such as large wood and debris dams, is detrimental to processes dependent upon transient storage in small, sand‐bed streams. Copyright © 2007 John Wiley & Sons, Ltd.
Bank lending in Germany and the UK: are there differences between a bank‐based and a market‐based country?
Authors: Kaufmann Sylvia , Valderrama Maria Teresa
Published: September 2007

We estimate Markov switching vector autoregressive systems for loans to firms and loans to households to investigate their relationship to interest rates and investment and consumption, respectively. We find evidence for different reactions of lending to shocks in real variables and interest rates across regimes both within countries and across countries for a given regime. We find evidence for a procyclical effect of lending during specific growth periods in both countries. Copyright © 2007 John Wiley & Sons, Ltd.
Integrated activation of MAP3Ks balances cell fate in response to stress
Authors: Winter‐Vann Ann M. , Johnson Gary L.
Published: September 2007

In vivo, tissues and organs are exposed to numerous stressors that require cells to respond appropriately for viability and homeostasis. Cells respond to these stressors, which range from UV irradiation, heat shock, chemicals, and changes in osmolality, to oxidative stress and inflammatory cytokines, by activating pathways that protect cells from damage. If the stress is too great, cells commit to undergo apoptosis. Such cell fate decisions involve the stress‐mediated activation of mitogen‐activated protein kinase (MAPK) networks, ultimately under the control of MAPK kinase kinases, or MAP3Ks. It is the MAP3Ks that coordinate the localization, duration and magnitude of MAPK activation in response to cell stress. A single stressor may activate several MAP3Ks, each of which impacts the balance between survival and apoptotic signaling. In this prospect article, we review the specific MAP3Ks that integrate the physiological response to cell stressors. The interrelationships among different stressors are discussed, with an emphasis on how the balance of signaling through MAP3Ks controls the MAPK response to determine cell fate. J. Cell. Biochem. 102: 848–858, 2007. © 2007 Wiley‐Liss, Inc.
Sperm binding glycoprotein (SBG) produces calcium and bicarbonate dependent alteration of acrosome morphology and protein tyrosine phosphorylation on boar sperm
Authors: Teijeiro Juan M. , Cabada Marcelo O. , Marini Patricia E.
Published: September 2007

The oviduct is a dynamic organ which modulates gamete physiology. Two subpopulations of sperm have been described in the oviduct of sows, a majority with normal appearance in the deep furrows and a minority, centrally located, and showing damaged membranes. Sperm–oviduct interaction provides the formation of a sperm storage and allows the selection of sperm with certain qualities. Pig (Sus scrofa) oviductal sperm binding glycoprotein (SBG) binds to sperm and exposes Galβ1‐3GalNAc. This disaccharide may be recognized by boar spermadhesin AQN1, which seems to be involved in sperm interaction with the oviduct. SBG is present at the apical surface of the epithelial cells that surround the lumen of the oviduct rather than at the bottom of the crypts. These characteristics imply it could be involved in sperm interaction with this organ. In this study, we evaluate the effect of SBG over boar sperm. We show that the presence of SBG produces alterations of the acrosome morphology of sperm only when they are incubated in capacitating conditions. SBG binds to the periacrosomal region of sperm undergoing capacitation. Its presence induces an increase on the tyrosine‐phosphorylation of a polypeptide of apparent molecular mass 97 kDa, as occurs with a 95 kDa protein in other mammalian sperm upon acrosomic reaction. Altogether, these results suggest that SBG might be involved in sperm selection by alteration of the acrosome of sperm that have already begun the capacitation process when they arrive to the oviduct. J. Cell. Biochem. 103: 1413–1423, 2008. © 2007 Wiley‐Liss, Inc.
Ab initio direct dynamics studies on the reactions of chlorine atom with CH3−nFnCH2OH (n = 1–3)
Authors: Wang Ying , Liu Jing‐Yao , Li Ze‐Sheng
Published: September 2007

The hydrogen abstraction reactions of Cl atom with a series of fluorinated alcohols, i.e., CH3−nFnCH2OH + Cl (n = 1–3) (R1–R3) have been studied systematically by ab initio direct dynamics method and the canonical variational transition state theory (CVT). The potential energy surface information is calculated at the MP2/6‐311G(d,p) level. Energies along the minimum energy paths are improved by a series of single‐point calculations at the higher modified GAUSSIAN‐2 (G2M) level of theory. Theoretical analysis shows that three kinds of hydrogen atoms can be abstracted from the reactants CH2FCH2OH and CHF2CH2OH, and for CF3CH2OH, two possible pathways are found. The rate constants for each reaction channel are evaluated by CVT with the small‐curvature tunneling correction (SCT) over a wide range of temperature from 200 to 2000 K. The calculated CVT/SCT rate constants are in good agreement with the available experimental values for the reactions CHF2CH2OH + Cl and CF3CH2OH + Cl. However, for the reaction CH2FCH2OH + Cl, there is negative temperature dependence below 500 K, which is different from the experimental fitted. It is shown that in the low temperature ranges, the three reactions all proceed predominantly via H‐abstraction from the methylene positions, and with the increase of the temperature the H‐abstraction channels from the fluorinated‐methyl positions should be taken into account, while the H‐abstraction channels from the hydroxyl groups are negligible over the whole temperature ranges. Also, the reactivity decreases substantially with fluorine substitution at the methyl position of alcohol. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Numerical characterization of the conformation of cyclic peptides and its application
Authors: Liu Xiaoqing , Xiu Zhilong , Li Xiaohui
Published: September 2007

Many classes of functional cyclic peptide molecules are determined by experimental techniques, but few similarities of cyclic peptides are detectable. We propose three numerical characterizations of conformations of cyclic peptides. By incorporating the information on atomic coordinates of cyclic peptides, the coordinates are transformed into a characteristic sequence. Then we calculate its center of gravity, the eigenvalues of its Euclidean and L/L matrices, and regard them as descriptors to numerically characterize the conformations of cyclic peptides. Finally, the method is tested by analyzing the similarities of cyclic peptides presented in Table . © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Sugar sensing by enterocytes combines polarity, membrane bound detectors and sugar metabolism
Authors: Le Gall Maude , Tobin Vanessa , Stolarczyk Emilie , Dalet Véronique , Leturque Armelle , Brot‐Laroche Edith
Published: September 2007

Sugar consumption and subsequent sugar metabolism are known to regulate the expression of genes involved in intestinal sugar absorption and delivery. Here we investigate the hypothesis that sugar‐sensing detectors in membranes facing the intestinal lumen or the bloodstream can also modulate intestinal sugar absorption. We used wild‐type and GLUT2‐null mice, to show that dietary sugars stimulate the expression of sucrase‐isomaltase (SI) and L‐pyruvate kinase (L‐PK) by GLUT2‐dependent mechanisms, whereas the expression of GLUT5 and SGLT1, did not rely on the presence of GLUT2. By providing sugar metabolites, sugar transporters, including GLUT2, fuelled a sensing pathway. In Caco2/TC7 enterocytes, we could disconnect the sensing triggered by detector from that produced by metabolism, and found that GLUT2 generated a metabolism‐independent pathway to stimulate the expression of SI and L‐PK. In cultured enterocytes, both apical and basolateral fructose could increase the expression of GLUT5, conversely, basolateral sugar administration could stimulate the expression of GLUT2. Finally, we located the sweet‐taste receptors T1R3 and T1R2 in plasma membranes, and we measured their cognate Galpha Gustducin mRNA levels. Furthermore, we showed that a T1R3 inhibitor altered the fructose‐induced expression of SGLT1, GLUT5, and L‐PK. Intestinal gene expression is thus controlled by a combination of at least three sugar‐signaling pathways triggered by sugar metabolites and membrane sugar receptors that, according to membrane location, determine sugar‐sensing polarity. This provides a rationale for how intestine adapts sugar delivery to blood and dietary sugar provision. J. Cell. Physiol. 213:834–843. © 2007 Wiley‐Liss, Inc.
Mitogenic signaling pathways induced by G protein‐coupled receptors
Authors: Rozengurt Enrique
Published: September 2007

G protein‐coupled receptor (GPCR) agonists, including neurotransmitters, hormones, chemokines, and bioactive lipids, act as potent cellular growth factors and have been implicated in a variety of normal and abnormal processes, including development, inflammation, and malignant transformation. Typically, the binding of an agonistic ligand to its cognate GPCR triggers the activation of multiple signal transduction pathways that act in a synergistic and combinatorial fashion to relay the mitogenic signal to the nucleus and promote cell proliferation. A rapid increase in the activity of phospholipases C, D, and A2 leading to the synthesis of lipid‐derived second messengers, Ca2+ fluxes and subsequent activation of protein phosphorylation cascades, including PKC/PKD, Raf/MEK/ERK, and Akt/mTOR/p70S6K is an important early response to mitogenic GPCR agonists. The EGF receptor (EGFR) tyrosine kinase has emerged as a transducer in the signaling by GPCRs, a process termed transactivation. GPCR signal transduction also induces striking morphological changes and rapid tyrosine phosphorylation of multiple cellular proteins, including the non‐receptor tyrosine kinases Src, focal adhesion kinase (FAK), and the adaptor proteins CAS and paxillin. The pathways stimulated by GPCRs are extensively interconnected by synergistic and antagonistic crosstalks that play a critical role in signal transmission, integration, and dissemination. The purpose of this article is to review recent advances in defining the pathways that play a role in transducing mitogenic responses induced by GPCR agonists. J. Cell. Physiol. 213:589–602. © 2007 Wiley‐Liss, Inc.
The osmotic sensitivity of rat growth plate chondrocytes in situ; clarifying the mechanisms of hypertrophy
Authors: Bush Peter G. , Parisinos Constantinos A. , Hall Andrew C.
Published: September 2007

Bone elongation is predominantly driven by the volume expansion of growth plate chondrocytes. This mechanism was initially believed to be “hypertrophy”, describing a proportional increase of cell water and organelles. However, morphometrical analysis subsequently assumed the increase to be “swelling”, resulting in a disproportionate increase of cell water (osmotically active fraction). Histological approaches were performed on fixed tissue, and for the “swelling” assumption to be valid, the osmotic sensitivity of living cells before and during volume increase should differ. To test this, analysis of images acquired by 2‐photon laser scanning microscopy (2PLSM) were used to determine the osmotic sensitivity, and osmotically active/inactive proportions of in situ chondrocytes from 15 living rat growth plates exposed to varying media osmolarities (∼0–580 mOsm). The dimensions of cell volume swelling in hypotonic media were different to the preferential lengthening seen in vivo, confirming the complexity of directional cell volume increase. Boyle–van't Hoff analysis of cell volume over the range of media osmolarity indicated no significant difference (Student's t‐test) in the osmotically inactive fraction, 39.5 ± 2.9% and 47.0 ± 4.3% (n = 13) for proliferative and hypertrophic zones, respectively, or the sensitivity of volume to changes in media osmolarity (proliferative 15.5 ± 0.8 and hypertrophic zone 15.5 ± 1.2%volume · Osm). The osmotic fractions did not change as chondrocytes progress from proliferative to hypertrophic regions of the growth plate. Our data suggest cell volume increase by hypertrophy may play a greater role in cell enlargement than swelling, and should be re‐evaluated as a mechanism responsible for growth plate chondrocyte volume increase and hence bone elongation. J. Cell. Physiol. 214: 621–629, 2008. © 2007 Wiley‐Liss, Inc.
Estrogen‐mediated activation of non‐genomic pathway improves macrophages cytokine production following trauma‐hemorrhage
Authors: Suzuki Takao , Yu Huang‐Ping , Hsieh Ya‐Ching , Choudhry Mashkoor A. , Bland Kirby I. , Chaudry Irshad H.
Published: September 2007

Although 17β‐estradiol (E2) attenuates the alterations in Kupffer cells and splenic macrophages (MΦ) cytokine production following trauma‐hemorrhage, the mechanism by which this occurs remains unknown. Utilizing a cell‐impermeable E2 conjugated with BSA (E2‐BSA), we examined the non‐genomic effects of E2 on the above two cell population cytokine production, MAPK and transcription factors activation following trauma‐hemorrhage. Male Sprague–Dawley rats underwent trauma‐hemorrhage (mean BP 40 mmHg for 90 min, then resuscitation). E2, E2‐BSA (1 mg/kg E2) with or without an estrogen receptor antagonist (ICI 182,780), or vehicle was administrated during resuscitation. Two hrs thereafter, Kupffer cells and SMΦ production of IL‐6, TNF‐α, and IL‐10, activation of MAPK (p38, ERK‐1/2, and JNK), and transcription factors (NF‐κB and AP‐1) were determined. IL‐6, TNF‐α, and IL‐10 productive capacity, MAPK, and transcription factors activation increased in Kupffer cells while they decreased in SMΦ following trauma‐hemorrhage. However, E2 administration normalized all of these alterations. Although E2‐BSA also attenuated the alterations in cytokine production/transcription factors, the values were higher in Kupffer cells and lower in SMΦ compared to shams. In contrast, E2‐BSA prevented trauma‐hemorrhage‐mediated changes in MAPK activation to the same extent as E2. Co‐administration of ICI 182,780 abolished E2‐BSA effects. Although some MAPK inhibitors suppressed cytokine production, the inhibitor effectiveness was dependent on cytokine, cell type and animal condition (trauma‐hemorrhage or sham). Thus, E2 effects on Kupffer cells and SMΦ cytokine production and transcription factors activation following trauma‐hemorrhage are mediated at least in part via non‐genomic pathway and these non‐genomic effects are likely mediated via MAPK pathways. J. Cell. Physiol. 214: 662–672, 2008. © 2007 Wiley‐Liss, Inc.
HMGB1 is a bone‐active cytokine
Authors: Yang Jieping , Shah Rita , Robling Alexander G. , Templeton Evan , Yang Huan , Tracey Kevin J. , Bidwell Joseph P.
Published: September 2007

High mobilitygroupbox 1 (HMGB1) is a chromatin protein that acts as an immunomodulatory cytokine upon active release from myeloid cells. HMGB1 is also an alarmin, an endogenous molecule released by dying cells that acts to initiate tissue repair. We have previously reported that osteoclasts and osteoblasts release HMGB1 and release by the latter is regulated by parathyroid hormone (PTH), an agent of bone remodeling. A recent study suggests that HMGB1 acts as a chemotactic agent to osteoclasts and osteoblasts during endochondral ossification. To explore the potential impact of HMGB1 in the bone microenvironment and its mechanism of release by osseous cells, we characterized the effects of recombinant protein (rHMGB1) on multiple murine bone cell preparations that together exhibit the various cell phenotypes present in bone. We also inquired whether apoptotic bone cells release HMGB1. rHMGB1 enhanced the RANKL/OPG steady state mRNA ratio and dramatically augmented the release of tumor necrosis factor‐alpha (TNFα) and interleukin‐6 (IL6) in osteoblastogenic bone marrow stromal cell (BMSC) cultures but not in the calvarial‐derived MC3T3‐E1 cells. Interestingly, rHMGB1 promoted GSK‐3beta phosphorylation in MC3T3‐E1 cells but not in BMSCs. Apoptotic bone cells released HMGB1, including MLO‐Y4 osteocyte‐like cells. MLO‐Y4 release of HMGB1 was coincident with caspase‐3 cleavage. Furthermore, the anti‐apoptotic action of PTH on MC3T3‐E1 cells correlated with the observed decrease in HMGB1 release. Our data suggest that apoptotic bone cells release HMGB1, that within the marrow HMGB1 is a bone resorption signal, and that intramembraneous and endochondral osteoblasts exhibit differential responses to this cytokine. J. Cell. Physiol. 214: 730–739, 2008. © 2007 Wiley‐Liss, Inc.