bluuebunny/crossref_metadata_2025_split huggingface dataset:
Supramolecular “Double‐Propeller” Dimers of Hexanuclear CuII/LnIII Complexes: A {Cu3Dy3}2 Single‐Molecule Magnet
Authors: Novitchi Ghenadie , Wernsdorfer Wolfgang , Chibotaru Liviu F. , Costes Jean‐Pierre , Anson Christopher E. , Powell Annie K. 
Published: January 2009

AbstractPropelling magnetism: Supramolecular organization leads to a remarkable dodecanuclear {Cu3Dy3}2 cluster with a “double–propeller” shape (see picture). The linkages of the CuDy units, both intramolecular and supramolecular, appear to be responsible for a drastic change in the single molecule magnetic behavior.magnified image
Artificial Ribozyme Switches Containing Natural Riboswitch Aptamer Domains
Authors: Wieland Markus , Benz Armin , Klauser Benedikt , Hartig Jörg S. 
Published: January 2009

AbstractRNA Lego: The use of natural riboswitch aptamers in synthetic RNA switches (see picture) should broaden the scope of artificial RNA regulators dramatically. It is shown that thiamine pyrophosphate (TPP) aptamers can be used in engineered devices as very sensitive switches of gene expression in unmodified organisms. The approach demonstrates that intrinsic metabolites can be utilized as external effectors of cellular functions.magnified image
A Chiral Concave‐Bound Cyclopentadienyl Iron Complex of Sumanene
Authors: Sakane Hiroyuki , Amaya Toru , Moriuchi Toshiyuki , Hirao Toshikazu 
Published: January 2009

AbstractGreat bowls of fire: The rotation of the cyclopentadienyl (Cp) ring is restricted in two concave‐bound monoalkyl‐substituted [CpFe(η6‐sumanene)]+ “π‐bowl” complexes (see picture). The asymmetric stacking of atropisomers was observed with a MeCpFe complex in the solid state and the chiral (S)‐sBuCpFe complex showed magnetic and optical desymmetrization of the sumanene ligand, which is the first example of a chiral complex of a π‐bowl ligand.magnified image
Enantiomerically Pure Chiral {Fe28} Wheels
Authors: Zhang Zhi‐Ming , Li Yang‐Guang , Yao Shuang , Wang En‐Bo , Wang Yong‐Hui , Clérac Rodolphe 
Published: January 2009

AbstractWheels of steel: Two enantiomerically pure chiral {Fe28} wheel‐like aggregates have been synthesized from the acetate buffer solution containing ferric ions and chiral tartrate ligands (see picture). These compounds are the largest chiral ferric aggregates isolated to date.magnified image
Pharmacodynamics of glucose regulation by methylprednisolone. II. normal rats
Authors: Jin Jin Y. , Jusko William J. 
Published: January 2009

AbstractA physiologic pharmacodynamic model was developed to jointly describe the effects of methylprednisolone (MPL) on adrenal suppression and glycemic control in normal rats. Six groups of animals were given MPL intravenously at 0, 10 and 50 mg/kg, or by subcutaneous 7 day infusion at rates of 0, 0.1 and 0.3 mg/kg/h. Plasma concentrations of MPL, corticosterone (CST), glucose and insulin were determined at various times up to 72 h after injection and 336 h after infusion. The pharmacokinetics of MPL was described by a two‐compartment model. A circadian rhythm for CST was found in untreated rats with a stress‐altered baseline caused by handling, which was captured by a circadian harmonic secretion rate with an increasing mesor. All drug treatments caused CST suppression. Injection of MPL caused temporary increases in glucose over 4 h. Insulin secretion was thereby stimulated yielding a later peak around 6 h. In turn, insulin can normalize glucose. However, long‐term dosing caused continuous hyperglycemia during and after infusion. Hyperinsulinemia was achieved during infusion, but diminished immediately after dosing despite the high glucose concentration. The effects of CST and MPL on glucose production were described with a competitive stimulation function. A disease progression model incorporating reduced endogenous glucose uptake/utilization was used to describe glucose metabolism under different treatments. The results exemplify the roles of endogenous and exogenous hormones in mediating glucose dynamics. The pharmacokinetic/pharmacodynamic model is valuable for quantitating diabetogenic effects of corticosteroid treatments and provides mechanistic insights into the hormonal control of the metabolic system. Copyright © 2009 John Wiley & Sons, Ltd.
The Homoscleromorph sponge Oscarellalobularis, a promising sponge model in evolutionary and developmental biology
Authors: Ereskovsky Alexander V. , Borchiellini Carole , Gazave Eve , Ivanisevic Julijana , Lapébie Pascal , Perez Thierry , Renard Emmanuelle , Vacelet Jean 
Published: January 2009

AbstractSponges branch basally in the metazoan phylogenetic tree and are believed to be composed of four distinct lineages with still uncertain relationships. Indeed, some molecular studies propose that Homoscleromorpha may be a fourth Sponge lineage, distinct from Demospongiae in which they were traditionally classified. They harbour many features that distinguish them from other sponges and are more evocative of those of the eumetazoans. They are notably the only sponges to possess a basement membrane with collagen IV and specialized cell‐junctions, thus possessing true epithelia. Among Homoscleromorphs, we have chosen Oscarella lobularis as a model species. This common and easily accessible sponge is characterized by relatively simple histology and cell composition, absence of skeleton, and strongly pronounced epithelial structure. In this review, we explore the specific features that make O. lobularis a promising homoscleromorph sponge model for evolutionary and developmental researches.
Microsatellite repeat instability and neurological disease
Authors: Brouwer Judith R. , Willemsen Rob , Oostra Ben A. 
Published: January 2009

AbstractOver 20 unstable microsatellite repeats have been identified as the cause of neurological disease in humans. The repeat nucleotide sequences, their location within the genes, the ranges of normal and disease‐causing repeat length and the clinical outcomes differ. Unstable repeats can be located in the coding or the non‐coding region of a gene. Different pathogenic mechanisms that are hypothesised to underlie the diseases are discussed. Evidence is given both from studies in simple model systems and from studies on human material and in animal models. Since somatic instability might affect the clinical outcome, this is briefly touched on. Available data and theories on the timing and mechanisms of the repeat instability itself are discussed, along with factors that have been observed to affect instability. Finally, the question of why the often harmful unstable repeats have been maintained throughout evolution is addressed.
Citrate transport and metabolism in mammalian cells
Authors: Mycielska Maria E. , Patel Ameet , Rizaner Nahit , Mazurek Maciej P. , Keun Hector , Patel Anup , Ganapathy Vadivel , Djamgoz Mustafa B. A. 
Published: January 2009

AbstractCitrate, an organic trivalent anion, is a major substrate for generation of energy in most cells. It is produced in mitochondria and used either in the Krebs' cycle or released into cytoplasm through a specific mitochondrial carriers. Citrate can also be taken up from blood through different plasma membrane transporters. In the cytoplasm, citrate can be used ultimately for fatty acid synthesis, which is increased in cancer cells. Here, we review the ways in which citrate can be transported and discuss the changes in transport and metabolism that occur in cancer cells. The primary focus is on the prostate gland, which is known to produce and release large amounts of citrate during its normal secretory function. The significant changes that occur in citrate‐related metabolism and transport in prostate cancer are the second focus. This review strives to relate these mechanisms to molecular biology on the one hand and to clinical applications on the other.
MicroRNA expression profiling in bone marrow: Implications in hematological malignancies
Authors: Costa Ana , Osório Catarina , Dias Sérgio 
Published: January 2009

AbstractMicroRNA (miRNA) have been recently attributed a crucial role in the control of gene expression in numerous physiological and pathological processes including growth, differentiation and even oncogenesis. Besides detailed mechanistic studies on their generation and function, there has been a great deal of interest in the study of miRNA as surrogate markers of disease. Numerous studies have attempted to define miRNA profiles as predictors of disease outcome, or for the classification/diagnosis of different pathologies. In the present review, we summarize the main studies describing the involvement of miRNA in bone marrow (BM) diseases and in normal BM function during hematopoiesis.
Site‐specific modification of the bovine genome using Cre recombinase‐mediated gene targeting.
Authors: Graham Catriona , Cole Sally , Laible Götz 
Published: January 2009

AbstractCre recombinase (Cre)‐mediated targeted insertion of a transgene is a powerful technique that can be used to tailor genomes. When combined with somatic cell nuclear transfer it could offer an efficient way to generate transgenic livestock with site‐specific genetic modifications that are free of antibiotic selection markers. We have engineered primary bovine fibroblasts to contain a chromosomal acceptor site with incompatible loxP/lox2272 sites for Cre‐mediated cassette exchange and show for the first time that Cre‐mediated targeting can be applied in these acceptor cells. Molecular characterization of the resulting cell clones revealed Cre‐mediated transgene insertion efficiencies of up to 98% when antibiotic selection was used to identify transgene containing cell clones. Most clonal lines also contained random insertions of the targeting and Cre expression plasmids with only about 10% of the clones being exclusively modified by the intended targeted insertion. This targeting efficiency was sufficient to enable the isolation of correctly targeted clones without the help of antibiotic selection. Therefore, this recombinase‐mediated insertion strategy has the potential to produce transgenic cattle from antibiotic selection marker‐free somatic cells with transgenes inserted into proven genomic loci ensuring reliable expression levels.
Electrospray‐ionization mass spectrometry as a tool for fast screening of protein structural properties
Authors: Grandori Rita , Santambrogio Carlo , Brocca Stefania , Invernizzi Gaetano , Lotti Marina 
Published: January 2009

AbstractSince the early 1990s, electrospray‐ionization mass spectrometry (ESI‐MS) has encountered growing interest as a complementary tool to established biochemical and biophysical methods for investigating protein structure and conformation. Nowadays, applications of ESI‐MS to protein investigation span from the area of analytical biochemistry to that of structural biology. This review focuses on applications of this technique to the analysis of protein conformational properties and molecular interactions, underscoring their possible relevance for molecular biotechnology, although representing a still very young field. An introductive section presents the major issues related to theoretical and technical aspects of ESI‐MS under non‐denaturing conditions. Examples from our work and from the literature illustrate which kind of information can be obtained concerning key issues in biotechnology such as stability and aggregation of proteins under both near‐native and challenging conditions, and interactions with other proteins, ligands and cofactors.
Biphasic mini‐reactor for characterization of biocatalyst performance
Authors: van den Wittenboer Anne , Schmidt Thomas , Müller Pia , Ansorge‐Schumacher Marion B. , Greiner Lasse 
Published: January 2009

AbstractBiphasic reaction media are extending the scope of technical biocatalysis. Thorough investigation of the factors affecting catalyst performance under these conditions is of key importance for the successful implementation of catalytic processes. Here, we present a reactor setup suitable for comprehensive systematic characterization and optimization of biocatalyzed reactions in biphasic systems with distinct phases. It is distinguished by small volumes allowing reproducible experimentation with minimum amounts of solvent and catalyst. The interfacial area is kept constant and independent stirring of both phases is allowed in order to minimize superimposing effects. Evaporation of low‐volatile organic solvents is prevented by use of airtight construction. The broad applicability of this mini‐reactor is demonstrated with regard to determination of mass transfer, enzyme productivity, and enzyme stability in both batch and continuous mode.
Political orientation and perceptions of adolescent autonomy and judicial culpability
Authors: Reppucci N. Dickon , Scott Elizabeth , Antonishak Jill 
Published: January 2009

AbstractThis study probed general attitudes about processing youths in adult criminal court across a range of offenses, explored attitudes about age of autonomous decision‐making for several activities outside the criminal justice context, and examined the interaction between these two realms. The major finding was that adults favor adult punishment of adolescent offenders at younger ages than they favor autonomy in other decision‐making contexts; the gap is widest for those who identify themselves as conservatives. Copyright © 2009 John Wiley & Sons, Ltd.
Modular hardware design for distant‐internet embedded systems engineering laboratory
Authors: Yue Xicai , Drakakis E. M. , Harkin J. , Callaghan M. J. , McGinnity T. M. , Maguire L. P. 
Published: January 2009

AbstractA novel hardware system providing remote accessible embedded system experiments of microcontroller, digital signal processor (DSP), and field‐programmable gate array (FPGA) via Internet is presented. Three newly developed hardware modules for integrating experimental boards, experimental instrumentation, and a PC workstation in the distant embedded laboratory are fully described. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 17: 389–397, 2009; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20259
Separation, optimization, miniaturization and signal space. Optimum measurability factors in process analytical chromatography
Authors: Smit Henri C. 
Published: January 2009

AbstractThe theory concerning optimum separation conditions with respect to the precision and minimum peak estimation error is extended with the derivation of the conditions for optimum measurability in case of chemical process control, resulting in extremely short columns to be used. High‐speed correlation chromatography (CC) with a special input device is suggested as a solution for the practical problems of these required columns. An example of a one‐second correlogram with a spark modulation input device is shown. An alternative is monitoring chemical processes by multiple input chromatography, applying a polynomial fit procedure. Copyright © 2009 John Wiley & Sons, Ltd.
Distinct Hydroxy‐Radical‐Induced Damage of 3′‐Uridine Monophosphate in RNA: A Theoretical Study
Authors: Zhang Ru bo , Eriksson Leif A. 
Published: January 2009

AbstractCutting ties: Strand scission and base release in hydroxy‐radical adducts of 3′‐uridine monophosphate (UMP) have been explored by using density functional theory. The presence of the ribose 2′‐OH group and the resultant formation of low‐barrier hydrogen bonds with oxygen atoms of the 3′‐phosphate linkage are highly important for hydrogen transfer and the subsequent bond‐breakage reactions (see picture).magnified imageRNA strand scission and base release in 3′‐uridine monophosphate (UMP), induced by OH radical addition to uracil, is studied at the DFT B3LYP/6‐31+G(d,p) level in the gas phase and in solution. In particular, the mechanism of hydrogen‐atom transfer subsequent to radical formation, from C2′ on the sugar to the C6 site on the base, is explored. The barriers of (C2′‐)H2′a abstraction by the C6 radical site range from 11.2 to 20.0 kcal mol−1 in the gas phase and 14.1 to 21.0 kcal mol−1 in aqueous solution, indicating that the local surrounding governs the hydrogen‐abstraction reaction in a stereoselective way. The calculated N1C1′ (N1–glycosidic bond) and β‐phosphate bond strengths show that homolytic and heterolytic bond‐breaking processes are largely favored in each case, respectively. The barrier for β‐phosphate bond rupture is approximately 3.2–4.0 kcal mol−1 and is preferred by 8–12 kcal mol−1 over N1–glycosidic bond cleavage in both the gas phase and solution. The β‐phosphate bond‐rupture reactions are exothermal in the gas phase and solution, whereas N1C1′ bond‐rupture reactions require both solvation and thermal corrections at 298 K to be energetically favored. The presence of the ribose 2′‐OH group and its formation of low‐barrier hydrogen bonds with oxygen atoms of the 3′‐phosphate linkage are highly important for hydrogen transfer and the subsequent bond‐breakage reactions.
Proton Pump for O2 Reduction Catalyzed by 5,10,15,20‐Tetraphenylporphyrinatocobalt(II)
Authors: Partovi‐Nia Raheleh , Su Bin , Li Fei , Gros Claude P. , Barbe Jean‐Michel , Samec Zdenek , Girault Hubert H. 
Published: January 2009

AbstractOxygen reduction: A polarized water|1,2‐dichloroethane (DCE) interface acts as a proton pump for the [Co(tpp)] (TPP=5,10,15,20‐tetraphenylporphyrinato) catalyzed O2 reduction by ferrocene (Fc) compounds to produce H2O2 (see figure; IT=ion transfer, ET=electron transfer). This system favours the collection of H2O2 by extraction immediately after its formation in DCE to the adjacent water phase.magnified imageThe role of 5,10,15,20‐tetraphenylporphyrinatocobalt(II) ([Co(tpp)]) as a catalyst on molecular oxygen (O2) reduction by ferrocene (Fc) and its two derivatives, 1,1′‐dimethylferrocene (DFc) and decamethylferrocene (DMFc) at a polarized water|1,2‐dichloroethane (DCE) interface has been studied. The water|DCE interface essentially acts as a proton pump controlled by the Galvani potential difference across the interface, driving the proton transfer from water to DCE. [Co(tpp)] catalyzed O2 reduction by Fc, DFc and DMFc is then followed to produce hydrogen peroxide (H2O2). The catalytic mechanism is similar to that proposed by Fukuzumi et al. for bulk reactions. This interfacial system provides a platform for a very efficient collection of H2O2, by extraction immediately after its formation in DCE to the adjacent water phase, thus decreasing the possibility of degradation and further reaction with ferrocene derivatives.
Spectroscopy Probing of the Formation, Recognition, and Conversion of a G‐Quadruplex in the Promoter Region of the bcl‐2 Oncogene
Authors: Li Huihui , Liu Yiquan , Lin Sen , Yuan Gu 
Published: January 2009

AbstractWhich form to take? The interconversion between the G‐quadruplex and duplex DNA forms in the bcl‐2 promoter could be induced by fluctuations in the pH value or DNA and NH4+ concentrations, by adding CH3OH, and by introducing small molecules (cationic porphyrin and dehydrocorydaline; see scheme).magnified imageThis study has demonstrated the formation of the G‐quadruplex structure from the G‐rich sequence in the promoter region of the bcl‐2 oncogene; the formation could be induced by addition of NH4+ or K+ ions. The binding affinity and stoichiometry of seven small molecules with the G‐quadruplex were examined by using ESI‐MS, as well as CD and UV spectroscopy. The binding‐affinity order was determined to be P1≈P5>P2>P3≈P4>P7>P6. In particular, the small‐molecule induction of the structural transition between the G‐quadruplex and duplex DNA forms in this promoter region was investigated by ESI‐MS. We directly observed specific binding of dehydrocorydaline (P7) and cationic porphyrin (P5) in one system consisting of the G‐quadruplex and the duplex DNA, respectively. The results indicate that P7 selectively stabilizes the G‐quadruplex and shifts the equilibrium toward G‐quadruplex formation of the bcl‐2 promoter, whereas P5 converts the G‐quadruplex into the duplex DNA, which results in strong and selective binding to the duplex form. Therefore, P5 and P7 with their attractive binding specificities could be considered as precursors for pathway‐specific drug design for regulation of bcl‐2 oncogene transcription.
Influence of the Charge State on the Structures and Interactions of Vancomycin Antibiotics with Cell‐Wall Analogue Peptides: Experimental and Theoretical Studies
Authors: Yang Zhibo , Vorpagel Erich R. , Laskin Julia 
Published: January 2009

AbstractCharge matters! The charge state significantly influences the conformation and the binding energy between vancomycin antibiotic and bacterial cell‐wall analogue peptides (see figure). Surface‐induced dissociation (SID) studies provide a quantitative comparison between the stabilities of different charge states of the complex.magnified imageIn this study we examined the effect of the charge state on the energetics and dynamics of dissociation of the noncovalent complex between the vancomycin and the cell‐wall peptide analogue Nα,Nε‐diacetyl‐L‐Lys‐D‐Ala‐D‐Ala (V–Ac2LKdAdA). The binding energies between the vancomycin and the peptide were obtained from the RRKM (Rice, Ramsperger, Kassel, Marcus) modeling of the time‐ and energy‐resolved surface‐induced dissociation (SID) experiments. Our results demonstrate that the stability of the complex towards fragmentation increases in the order: doubly protonated<singly protonated<deprotonated. Dissociation of the singly protonated and singly deprotonated complex is characterized by very large entropy effects, which indicate a substantial increase in the conformational flexibility of the resulting products. The experimental threshold energies of (1.75±0.08) eV ((40.3±1.8) kcal mol−1) and (1.34±0.08) eV ((30.9±1.8) kcal mol−1) obtained for the deprotonated and singly protonated complexes, respectively, are in excellent agreement with the results of density functional theory calculations. The increased stability of the deprotonated complex observed experimentally is attributed to the presence of three charged sites in the deprotonated complex, as compared with only one charged site in the singly protonated complex. The low binding energy of (0.93±0.04) eV ((21.4±0.9) kcal mol−1) obtained for the doubly protonated complex suggests that this ion is destabilized by Coulomb repulsion between the singly protonated vancomycin and the singly protonated peptide comprising the complex.
A Ratiometric Fluorescent Probe for Hypochlorite Based on a Deoximation Reaction
Authors: Lin Weiying , Long Lingliang , Chen Bingbing , Tan Wen 
Published: January 2009

AbstractThe first ratiometric fluorescent probe for hypochlorite has been developed through regulation of the electron‐withdrawing ability of the electron acceptor in an intramolecular charge‐transfer (ICT) system by a deoximation reaction (see figure; EWG=electron‐withdrawing group).magnified imageIn this work, we have successfully provided a novel strategy for the rational design and synthesis of a ratiometric fluorescent probe for hypochlorite. The strategy is based on the deoximation reaction, which has not yet been used in the fluorescent hypochlorite probe design. Interestingly, the probe showed a ratiometric fluorescent response to hypochlorite with the emission intensities ratio (I509/I439) increasing from 0.28 to 2.74. Furthermore, the probe displayed high selectivity for hypochlorite over other species due to the distinct deoximation conditions. The probe developed herein represents the first ratiometric fluorescent probe for hypochlorite.