bluuebunny/crossref_metadata_2025_split huggingface dataset:
Secular variation of hemispheric phase differences in the solar cycle
Authors: Zolotova N.V. , Ponyavin D.I. , Arlt R. , Tuominen I. 
Published: September 2010

AbstractWe investigate the phase difference of the sunspot cycles in the two hemispheres and compare it with the latitudinal sunspot distribution. If the north‐south phase difference exhibits a long‐term tendency, it should not be regarded as a stochastic phenomenon. We use datasets of historical sunspot records and drawings made by Staudacher, Hamilton, Gimingham, Carrington, Spörer, and Greenwich observers, as well as the sunspot activity during the Maunder minimum reconstructed by Ribes and Nesme‐Ribes. We employ cross‐recurrence plots to analyse north‐south phase differences. We show that during the last 300 years, the persistence of phase‐leading in one of the hemispheres exhibits a secular variation. Changes from one hemisphere to the other leading in phase were registered near 1928 and 1968 as well as two historical ones near 1783 and 1875. A long‐term anticorrelation between the hemispheric phase differences in the sunspot cycles and the latitudinal distribution of sunspots was traced since 1750 (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Syntheses and Photophysical Properties of N‐Pyridylimidazol‐2‐ylidene Tetracyanoruthenates(II) and Photochromic Studies of Their Dithienylethene‐Containing Derivatives
Authors: Duan Gongping , Yam Vivian Wing‐Wah 
Published: September 2010

AbstractA series of tetracyanoruthenate(II) with chelating pyridyl N‐heterocyclic carbene ligands (NHC‐py) was synthesized and characterized. Their photophysical and electrochemical properties as well as the photochromic behavior of their dithienylethene‐containing complexes were studied. Photocyclization was found to take place upon irradiation into the metal‐to‐ligand charge transfer (MLCT) absorption bands of these complexes, and evidence is provided to support the triplet‐sensitizing reaction pathway.
Solution Structure, Mechanism of Replication, and Optimization of an Unnatural Base Pair
Authors: Malyshev Denis A. , Pfaff Danielle A. , Ippoliti Shannon I. , Hwang Gil Tae , Dwyer Tammy J. , Romesberg Floyd E. 
Published: September 2010

AbstractAs part of an ongoing effort to expand the genetic alphabet for in vitro and eventual in vivo applications, we have synthesized a wide variety of predominantly hydrophobic unnatural base pairs and evaluated their replication in DNA. Collectively, the results have led us to propose that these base pairs, which lack stabilizing edge‐on interactions, are replicated by means of a unique intercalative mechanism. Here, we report the synthesis and characterization of three novel derivatives of the nucleotide analogue dMMO2, which forms an unnatural base pair with the nucleotide analogue d5SICS. Replacing the para‐methyl substituent of dMMO2 with an annulated furan ring (yielding dFMO) has a dramatically negative effect on replication, while replacing it with a methoxy (dDMO) or with a thiomethyl group (dTMO) improves replication in both steady‐state assays and during PCR amplification. Thus, dTMO–d5SICS, and especially dDMO–d5SICS, represent significant progress toward the expansion of the genetic alphabet. To elucidate the structure–activity relationships governing unnatural base pair replication, we determined the solution structure of duplex DNA containing the parental dMMO2–d5SICS pair, and also used this structure to generate models of the derivative base pairs. The results strongly support the intercalative mechanism of replication, reveal a surprisingly high level of specificity that may be achieved by optimizing packing interactions, and should prove invaluable for the further optimization of the unnatural base pair.
The Total Synthesis of (±)‐Fumimycin
Authors: Gross Patrick J. , Bräse Stefan 
Published: September 2010

AbstractThe antibiotic agent fumimycin has been synthesized for the first time. This natural product was found to inhibit the bacterial peptide deformylase and may represent a lead structure to a class of novel antibacterials. Our synthetic strategy towards fumimycin involved the following steps: Dakin oxidation of an aldehyde functionality, conversion of an oxime through radical fragmentation to form an N‐diphenylphosphoryl group, construction of an α‐trisubstituted amine by 1,2‐addition to a ketimine, a Claisen rearrangement with subsequent transition‐metal‐catalyzed olefin isomerization to install a propenyl chain and final amidation.
Glyco‐pseudopolyrotaxanes: Carbohydrate Wheels Threaded on a Polymer String and Their Inhibition of Bacterial Adhesion
Authors: Kim Jeeyeon , Ahn Youngjoo , Park Kyeng Min , Lee Don‐Wook , Kim Kimoon 
Published: September 2010

AbstractWe report glyco‐pseudopolyrotaxanes composed of cucurbit[6]uril‐based mannose wheels (ManCB[6]) threaded on polyviologen (PV), which not only effectively induce bacterial aggregation, but also exhibit high inhibitory activity against bacterial binding to host cells. Three glyco‐pseudopolyrotaxanes (1–3), which have 10, 5, and 3 ManCB[6] wheels, respectively, on a PV string, were prepared and characterized. Bacterial aggregation assays and hemagglutination inhibition assays illustrated the specific and multivalent interaction between the glyco‐pseudopolyrotaxanes and E. coli ORN178. Compound 3 was especially effective at inducing bacterial aggregation and showed 300 times higher inhibitory potency than monomeric methyl‐α‐mannoside (Me‐αMan) for ORN178‐induced hemagglutination. Furthermore, we demonstrated their inhibitory activities for the adhesion of ORN178 bacteria to urinary epithelial cells as a model of urinary tract infection. Our findings suggest that these supramolecular carbohydrate clusters are potentially useful in antiadhesion therapy.
Molecular Gallium Arsenide Phosphide Clusters Prepared from AsP3, P4, and [{GaC(SiMe3)3}4]
Authors: Cossairt Brandi M. , Cummins Christopher C. 
Published: September 2010

AbstractTreatment of AsP3 with 0.75 equivalents of [{GaC(SiMe3)3}4] resulted in selective insertion of three equivalents of {GaC(SiMe3)3} into the three AsP bonds to give [As{GaC(SiMe3)3}3P3] (1‐As) with an intact cyclo‐P3 ring. This yellow compound has been characterized by NMR spectroscopy, combustion analysis, single‐crystal X‐ray diffraction, UV/Vis spectroscopy, Raman spectroscopy, and cyclic voltammetry (THF, 0.2 M [TBA][B(C6F5)4]; TBA=tetrabutyl ammonium). Computational models of 1‐As and the isomeric [P{GaC(SiMe3)3}3AsP2] (1‐P) have been investigated as well, revealing several interesting electronic features of these cage molecules. Following from the cyclic voltammetry studies of 1‐As that highlight an irreversible two‐electron reduction at −2.2 V versus Fc/Fc+, treatment with one equivalent of [Mg(C14H10)(thf)3] resulted in two‐electron reduction to provide [As{GaC(SiMe3)3}3P3Mg(thf)3] (2), in which the Mg2+ ion has inserted into one of the PP bonds of the cyclo‐P3 ring. It was also found that treatment of AsP3 or P4 with one equivalent of [{GaC(SiMe3)3}4] resulted in formation of the quadruple insertion products [As{GaC(SiMe3)3}4P3] (3) and [P{GaC(SiMe3)3}4P3] (4), respectively.
A Continuous Flow Process Using a Sequence of Microreactors with In‐line IR Analysis for the Preparation ofN,N‐Diethyl‐4‐(3‐fluorophenylpiperidin‐4‐ylidenemethyl)benzamide as a Potent and Highly Selective δ‐Opioid Receptor Agonist
Authors: Qian Zizheng , Baxendale Ian R. , Ley Steven V. 
Published: September 2010

AbstractThis article describes the design, optimisation and development of a continuous flow synthesis ofN,N‐diethyl‐4‐(3‐fluorophenylpiperidin‐4‐ylidenemethyl)benzamide, a potent δ‐opioid receptor agonist developed by AstraZeneca. The process employs a sequence of flow‐based microreactors, with integrated purification employing solid‐supported reagents and in‐line IR analytical protocols using a newly developed ReactIR flow cell. With this monitoring device, initiation of the fourth input flow stream can be precisely controlled during the synthesis.
Novel Huprine Derivatives with Inhibitory Activity toward β‐Amyloid Aggregation and Formation as Disease‐Modifying Anti‐Alzheimer Drug Candidates
Authors: Viayna Elisabet , Gómez Tània , Galdeano Carles , Ramírez Lorena , Ratia Míriam , Badia Albert , Clos M. Victòria , Verdaguer Ester , Junyent Félix , Camins Antoni , Pallàs Mercè , Bartolini Manuela , Mancini Francesca , Andrisano Vincenza , Arce Mariana P. , Rodríguez‐Franco María Isabel , Bidon‐Chanal Axel , Luque F. Javier , Camps Pelayo , Muñoz‐Torrero Diego 
Published: September 2010

AbstractA new family of dual binding site acetylcholinesterase (AChE) inhibitors has been designed, synthesized, and tested for their ability to inhibit AChE, butyrylcholinesterase (BChE), AChE‐induced and self‐induced β‐amyloid (Aβ) aggregation and β‐secretase (BACE‐1), and to cross the blood–brain barrier. The new heterodimers consist of a unit of racemic or enantiopure huprine Y or X and a donepezil‐related 5,6‐dimethoxy‐2‐[(4‐piperidinyl)methyl]indane moiety as the active site and peripheral site to mid‐gorge‐interacting moieties, respectively, connected through a short oligomethylene linker. Molecular dynamics simulations and kinetics studies support the dual site binding to AChE. The new heterodimers are potent inhibitors of human AChE and moderately potent inhibitors of human BChE, AChE‐induced and self‐induced Aβ aggregation, and BACE‐1, and are predicted to be able to enter the central nervous system (CNS), thus constituting promising multitarget anti‐Alzheimer drug candidates with the potential to modify the natural course of this disease.
Surfactant‐assisted synthesis of novel star‐like PbWO4 hierarchical architectures
Authors: Tang Hua , Wu Qiong , Yang Xiaofei , Yang Bin , Li Changsheng 
Published: September 2010

AbstractLarge‐scale star‐like PbWO4 hierarchical architectures were controllably synthesized by a facile surfactant‐assisted technology under mild conditions in the presence of a mixed solvent of ethylene glycol and water. The morphology, structure, and phase composition of PbWO4 architectures were characterized by X‐ray diffraction (XRD), field emission scanning electron microscopy (FE‐SEM), field emission transmission electron microscopy (FE‐TEM), and nitrogen adsorption‐desorption isotherms. The possible formation mechanism of the star‐like PbWO4 architectures (initial nucleating stage and a subsequent self‐assembly stage) was proposed based on the observations from a time‐dependent morphology evolution process, which may pave the way to shape‐controlled synthesis of inorganic nanocrystals with the complex structures. This route provides a facile strategy to fabricate complex hierarchical PbWO4 structures. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
TLR5 or NLRC4 is necessary and sufficient for promotion of humoral immunity by flagellin
Authors: Vijay‐Kumar Matam , Carvalho Frederic A. , Aitken Jesse D. , Fifadara Nimita H. , Gewirtz Andrew T. 
Published: September 2010

AbstractThe fact that some TLR‐based vaccine adjuvants maintain function in TLR‐deficient hosts highlights that their mechanism of function remains incompletely understood. Thus, we examined the ability of flagellin to induce cytokines and elicit/promote murine antibody responses upon deletion of the flagellin receptors TLR5 and/or NLRC4 (also referred to as IPAF) using a prime/boost regimen. In TLR5‐KO mice, flagellin failed to induce NF‐κB‐regulated cytokines such as keratinocyte‐derived chemokine (CXCL1) but induced WT levels of the inflammasome cytokine IL‐18 (IL‐1F4). Conversely, in NLRC4‐KO mice, flagellin induced keratinocyte‐derived chemokine, but not IL‐18, whereas TLR5/NLRC4‐DKO lacked induction of all cytokines measured. Flagellin/ovalbumin treatment resulted in high‐antibody titers to both flagellin and ovalbumin in WT, TLR5‐KO and DKO mice but did not elicit antibodies to either in TLR5/NLRC4‐DKO mice. Thus, flagellin's ability to elicit/promote humoral immunity requires a germ‐line‐encoded receptor capable of recognizing this molecule. Such promotion of adaptive immunity can be effectively driven by either TLR5‐mediated activation of NF‐κB or NLRC4‐mediated activation of the inflammasome.
Dendritic cells adhere to and transmigrate across lymphatic endothelium in response to IFN‐α
Authors: Rouzaut Ana , Garasa Saray , Teijeira Álvaro , González Iranzu , Martinez‐Forero Ivan , Suarez Natalia , Larrea Esther , Alfaro Carlos , Palazón Asís , Dubrot Juan , Hervás‐Stubbs Sandra , Melero Ignacio 
Published: September 2010

AbstractMigration of DC into lymphatic vessels ferries antigenic cargo and pro‐inflammatory stimuli into the draining LN. Given that tissues under the influence of viral infections produce type I IFN, it is conceivable that these cytokines enhance DC migration in order to facilitate an antiviral immune response. Cultured lymphatic endothelium monolayers pretreated with TNF‐α were used to model this phenomenon under inflammatory conditions. DC differentiated in the presence of either IFN‐α2b or IFN‐α5 showed enhanced adhesion to cultured lymphatic endothelial cells. These pro‐adhesive effects were mediated by DC, not the lymphatic endothelium, and correlated with increased DC transmigration across lymphatic endothelial cell monolayers. Transmigration was guided by chemokines acting on DC, and blocking experiments with mAb indicated a role for LFA‐1. Furthermore, incubation of DC with IFN‐α led to the appearance of active conformation epitopes on the CD11a integrin chains expressed by DC. Differentiation of mouse DC in the presence of IFN‐α also increased DC migration from inflammed footpads toward popliteal LN. Collectively, these results indicate a role for type I IFN in directing DC toward LN under inflammatory conditions.
IFN‐γ and IL‐12 synergize to convert in vivo generated Th17 into Th1/Th17 cells
Authors: Lexberg Maria H. , Taubner Annegret , Albrecht Inka , Lepenies Inga , Richter Anne , Kamradt Thomas , Radbruch Andreas , Chang Hyun‐Dong 
Published: September 2010

AbstractTh1 and Th17 cells are distinct lineages of effector/memory cells, imprinted for re‐expression of IFN‐γ and IL‐17, by upregulated expression of T‐bet and retinoic acid‐related orphan receptor γt (RORγt), respectively. Apparently, Th1 and Th17 cells share tasks in the control of inflammatory immune responses. Th cells coexpressing IFN‐γ and IL‐17 have been observed in vivo, but it remained elusive, how these cells had been generated and whether they represent a distinct lineage of Th differentiation. It has been shown that ex vivo isolated Th1 and Th17 cells are not interconvertable by TGF‐β/IL‐6 and IL‐12, respectively. Here, we show that ex vivo isolated Th17 cells can be converted into Th1/Th17 cells by combined IFN‐γ and IL‐12 signaling. IFN‐γ is required to upregulate expression of the IL‐12Rβ2 chain, and IL‐12 for Th1 polarization. These Th1/Th17 cells stably coexpress RORγt and T‐bet at the single‐cell level. Our results suggest a molecular pathway for the generation of Th1/Th17 cells in vivo, which combine the pro‐inflammatory potential of Th1 and Th17 cells.
Memory‐like IFN‐γ response by NK cells following malaria infection reveals the crucial role of T cells in NK cell activation by P. falciparum
Authors: McCall Matthew B. B. , Roestenberg Meta , Ploemen Ivo , Teirlinck Anne , Hopman Joost , de Mast Quirijn , Dolo Amagana , Doumbo Ogobara K. , Luty Adrian , van der Ven André J. A. M. , Hermsen Cornelus C. , Sauerwein Robert W. 
Published: September 2010

AbstractNK cells are rapid IFN‐γ responders to Plasmodium falciparum‐infected erythrocytes (PfRBC) in vitro and are involved in controlling early parasitaemia in murine models, yet little is known about their contribution to immune responses following malaria infection in humans. Here, we studied the dynamics of and requirements for in vitro NK responses to PfRBC in malaria‐naïve volunteers undergoing a single experimental malaria infection under highly controlled circumstances, and in naturally exposed individuals. NK‐specific IFN‐γ responses to PfRBC following exposure resembled an immunological recall pattern and were tightly correlated with T‐cell responses. However, although PBMC depleted of CD56+ cells retained 20–55% of their total IFN‐γ response to PfRBC, depletion of CD3+ cells completely abrogated the ability of remaining PBMC, including NK cells, to produce IFN‐γ. Although NK responses to PfRBC were partially dependent on endogenous IL‐2 signaling and could be augmented by exogenous IL‐2 in whole PBMC populations, this factor alone was insufficient to rescue NK responses in the absence of T cells. Thus, NK cells make a significant contribution to total IFN‐γ production in response to PfRBC as a consequence of their dependency on (memory) T‐cell help, with likely positive implications for malaria vaccine development.
Enhanced responsiveness to T‐cell help causes loss of B‐lymphocyte tolerance to a β‐cell neo‐self‐antigen in type 1 diabetes prone NOD mice
Authors: Cox Selwyn Lewis , Stolp Jessica , Hallahan Nicole L. , Counotte Jacqueline , Zhang Wenyu , Serreze David V. , Basten Antony , Silveira Pablo A. 
Published: September 2010

AbstractSelf‐reactive B lymphocytes contribute to type 1 diabetes pathogenesis as APC and auto‐Ab producers in NOD mice and humans. To shed light on the mechanisms responsible for the breakdown in B‐lymphocyte self‐tolerance to β‐cell Ag, we utilised a model whereby hen‐egg lysozyme (HEL)‐specific Ig Tg (IgHEL‐Tg)‐Tg B lymphocytes were allowed to develop in or were transferred into mice expressing the HEL Tg under an insulin promoter (insHEL‐Tg). IgHEL‐Tg B lymphocytes enhanced type 1 diabetes susceptibility of insHEL‐Tg NOD mice. A comparison of the tolerogenic activity of IgHEL‐Tg B lymphocytes with NOD and non‐autoimmune‐prone C57BL/6 genetic backgrounds showed that both were rendered anergic in the presence of insHEL when competing with polyclonal B lymphocytes. Nevertheless, NOD IgHEL‐Tg B lymphocytes transferred into insHEL‐Tg mice were more readily susceptible to rescue from anergy than their C57BL/6 counterparts, following provision of in vivo T‐cell help. The different tolerogenic outcomes were an intrinsic property of B lymphocytes rather than being related to the quality of T‐cell help, with the defective response being at least partially controlled by genes mapping to insulin‐dependent diabetes (Idd) susceptibility loci on Chromosome 1 (Idd5) and 4 (Idd9/11).
Zinc(II) and Cadmium(II) Coordination Polymers Based on 3‐(5H‐Tetrazolyl)benzoate Ligand with Different Coordination Modes: Hydrothermal Syntheses, Crystal Structures and Ligand‐Centered Luminescence
Authors: Chen Feng , Wu Mei‐Feng , Liu Guang‐Ning , Wang Ming‐Sheng , Zheng Fa‐Kun , Yang Chen , Xu Zhong‐Ning , Liu Zhi‐Fa , Guo Guo‐Cong , Huang Jin‐Shun 
Published: September 2010

AbstractHydrothermal reaction of Na(3‐cba) (3‐cba = 3‐cyanobenzoate), NaN3 and a metal salt with either 2,2′‐bipyridine (2,2′‐bipy) or 1,10‐phenanthroline (phen) afforded four novel ZnII/CdII polymers, which have been structurally characterized by single‐crystal X‐ray diffraction analysis. In situ [2 + 3] cycloaddition reaction of nitrile and azide in the presence of a ZnII or CdII salt yielded the ligand 3‐(5H‐tetrazolyl)benzoate (3‐tzba2–) [3‐H2tzba = 3‐(5H‐tetrazolyl)benzoic acid]. The obtained polymers are formulated as [Zn2(3‐tzba)(N3)(OH)(2,2′‐bipy)] (1), [Zn(3‐tzba)(2,2′‐bipy)(H2O)]·3H2O (2), [Zn2(3‐tzba)2(phen)2]·H2O (3) and [Cd4(3‐tzba)2(N3)4(2,2′‐bipy)3]·H2O (4). A crystalline mixture of ZnII polymers 1 and 2 with infinite ladder‐like chain and zigzag chain structures, respectively, was obtained from the reaction in the presence of 2,2′‐bipy. The replacement of 2,2′‐bipy with phen as an auxiliary ligand yielded 3, which shows a pearl‐necklace‐like chain structure. Further, the introduction of CdII instead of ZnII resulted in the formation of 4, which has a 2D corrugated layer structure. The 3‐tzba2– ligands display four different coordination modes in 1–4, and modes μ2‐κN2:κO1,O2 (in 2) and μ3‐κN3:κO1:κO2 (in 3) are observed in tetrazolate‐5‐carboxylate polymers for the first time. Photoluminescent studies in the solid state at room and low temperature revealed that 1–4 exhibit interesting luminescent behaviors, and the relevant density of states (DOS) calculation results showed that their photoluminescence mainly originates from ligand‐centered emission and is dependent on the organic ligand incorporated into the polymer.
Dispersive liquid–liquid microextraction combined with nonaqueous capillary electrophoresis for the determination of fluoroquinolone antibiotics in waters
Authors: Herrera‐Herrera Antonio V. , Hernández‐Borges Javier , Borges‐Miquel Teresa M. , Rodríguez‐Delgado Miguel Á. 
Published: September 2010

AbstractDispersive liquid–liquid microextraction (DLLME) was combined for the first time with NACE‐UV for the selective determination of eight fluoroquinolone antibiotics (lomefloxacin, levofloxacin, marbofloxacin, ciprofloxacin, sarafloxacin, enrofloxacin, danofloxacin and difloxacin) in mineral and run‐off waters. Field‐enhanced sample injection was carried out in order to improve the sensitivity, whereas pipemidic acid was used as internal standard. The BGE that provided complete separation of the eight analytes and the internal standard was composed of 3 M acetic acid, 49 mM ammonium acetate in 55:45 v/v methanol:ACN. Optimum DLLME conditions (extraction of 5 mL of water at pH 7.6 with 685 μL of CHCl3 and 1250 μL of ACN, extractant and disperser solvents, respectively) were achieved by means of experimental design methodology. Calibration curves of the whole method were obtained with correlation coefficients (R) higher than 0.994 in all cases. An accuracy and precision study was carried out at different levels of concentration, finding that there were no significant differences (Student's t‐test) between real and spiked concentrations.
Principles of scaling and similarity for testing of lead–rubber bearings
Authors: Kalpakidis Ioannis V. , Constantinou Michael C. 
Published: September 2010

AbstractLead–rubber bearings are seismic isolators that have been extensively used to protect buildings, bridges and mission‐critical infrastructure from the damaging effects of earthquake shaking. Testing of isolators, including lead–rubber bearings, is conducted either for research purposes (for example, shake table testing) or for determination of their properties before their use in applications (prototype and quality‐control testing). Testing is of significance as it (a) provides the data needed to validate complex models for analysis, and (b) results in basic mechanical properties of the tested isolators for use in analysis and design. Often testing has to be performed on reduced‐size bearings and/or at conditions of reduced speed of motion due, primarily, to unavailability of testing equipment capable of testing full‐size specimens at realistic dynamic conditions. When testing at reduced size, the conditions of testing need to be adjusted on the basis of scientific analysis so that the test results represent the behavior of the full‐size prototype bearing. This paper examines the issue of testing of lead–rubber bearings at reduced scale and presents the necessary conditions for testing in order to correctly reproduce the critical effects of lead core heating on the characteristic strength of the bearing. Experimental results on large‐size and reduced‐size bearings are used to demonstrate the concepts. Copyright © 2010 John Wiley & Sons, Ltd.