bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Efficient Three‐Step Synthesis of Cyclopenta[b]pyrans via 2‐Donor‐Substituted Fischer Ethenylcarbenechromium Complexes
Authors: de Meijere Armin , Schirmer Heiko , Stein Frank , Funke Frank , Duetsch Michael , Wu Yao‐Ting , Noltemeyer Mathias , Belgardt Thomas , Knieriem Burkhard 
Published: April 2005

AbstractA wide range of cyclopenta[b]pyrans 4 has been synthesized in a one‐pot reaction by treatment of different 2‐donorsubstituted ethenylcarbenechromium complexes 2 with alkynes in THF in moderate to excellent yields (41–90 % for 14 out of 25 examples). The starting materials 2 are readily available in good to excellent yields (76–99 % for 25 out of 36 examples) by Michael addition of amines, alcohols and thiols, respectively, to the corresponding alkynylcarbenechromium complexes 1. Due to their 10 π‐electrons in a cross‐conjugated bicyclic system, cyclopenta[b]pyrans have been termed pseudoazulenes, as they indeed have similar UV/Vis‐spectroscopic properties.
Metal‐Directed Synthesis and Photophysical Studies of Trinuclear V‐Shaped and Pentanuclear X‐Shaped Ruthenium and Osmium Metallorods and Metallostars Based upon 4′‐(3,5‐Dihydroxyphenyl)‐2,2′:6′,2′′‐terpyridine Divergent Units
Authors: Constable Edwin C. , Handel Robyn W. , Housecroft Catherine E. , Farràn Morales Angeles , Ventura Barbara , Flamigni Lucia , Barigelletti Francesco 
Published: April 2005

AbstractA new series of V‐shaped trinuclear metallorods and X‐shaped pentanuclear metallostars has been prepared by the reaction of metal complexes bearing pendant phenolic functionalities with complexes containing electrophilic ligands. Specifically, {M(tpy)2} motifs (M=Ru or Os; tpy=2,2′:6′,2′′‐terpyridine) bearing one or two pendant 3,5‐dihydroxyphenyl substituents at the 4‐position of the central ring of the tpy have been reacted with the complexes [Ru(tpy)(Xtpy)]2+ (X=Cl or Br) to form new ether‐linked species. The energy transfer from ruthenium to osmium in these complexes has been investigated in detail and the efficiency of transfer shown to be highly temperature dependent; the energy transfer is highly efficient at low temperature, whereas at room temperature nonradiative and nontransfer deactivation of the excited {Ru(tpy)2}* domains is most significant.
A Dispensable Methoxy Group? Phenyl Fencholate as a Chiral Modifier of n‐Butyllithium
Authors: Goldfuss B. , Steigelmann M. , Löschmann T. , Schilling G. , Rominger F. 
Published: April 2005

AbstractPhenyl fenchol forms a 3:1 aggregate with n‐butyllithium (3‐BuLi), showing unique lithium–HC agostic interactions both in toluene solution (1H,7Li‐HOESY) and in the solid state (X‐ray analysis). Although methoxy–lithium coordination is characteristic for many mixed aggregates of anisyl fencholates with n‐butyllithium, endo‐methyl coordination to lithium ions compensates for the missing methoxy groups in 3‐BuLi. This gives rise to a different orientation of the fenchane moiety, encapsulating and chirally modifying the butylide unit.
Interferon α therapy for patients with essential thrombocythemia
Authors: Saba Rashid , Jabbour Elias , Giles Francis , Cortes Jorge , Talpaz Moshe , O'Brien Susan , Freireich Emil J. , Garcia‐Manero Guillermo , Kantarjian Hagop , Verstovsek Srdan 
Published: April 2005

AbstractBACKGROUNDIn 1986, a Phase II trial of recombinant interferon‐α (IFN‐α) was initiated as therapy for patients with essential thrombocythemia (ET).METHODSPatients were treated with subcutaneous IFN‐α at a dose of 5 × 106 units/m2 daily. In responding patients, the therapy lasted at least 3 years.RESULTSTwenty‐three patients (14 females and 9 males; median age, 41 years; age range, 20–63 years) with a median platelet count of 1350 × 109/L were treated. After a median follow‐up of 174 months (14.5 years), 15 of 20 evaluable patients (75%) responded, including 14 patients who achieved a complete hematologic response (CHR) (6 of them with bone marrow remission) and 1 patient who demonstrated a partial response. The median time to response was 6 months (range, 0.5–36 months), and the median response duration was 48 months (range, 5–114 months). Seven patients who achieved a CHR and were taken off therapy after they completed 3 years of maintenance therapy sustained their response for a median of 28 months. No symptoms or signs of thrombosis or hemorrhage were observed in responding patients. Eleven of 14 patients (78%) who achieved a CHR developed a recurrence, and 2 of 5 patients with recurrences who were rechallenged with IFN‐α achieved a second response. The treatment was tolerated relatively well.CONCLUSIONSIFN‐α was safe and effective therapy for patients with ET, and the ability of IFN‐α to reverse disease pathology and possibly modify the clinical course of patients with ET warrants its investigation in larger, prospective trials. Cancer 2005. © 2005 American Cancer Society.
Immunolocalization of Bex protein in the mouse brain and olfactory system
Authors: Koo Jae Hyung , Saraswati Manda , Margolis Frank L. 
Published: April 2005

AbstractBex proteins are expressed from a family of “brain expressed X‐linked genes” that are closely linked on the X‐chromosome. Bex1 and 2 have been characterized as interacting partners of the olfactory marker protein (OMP). Here we report the distribution of Bex1 and Bex2 mRNAs in several brain regions and the development and characterization of an antibody to mouse Bex1 protein that cross‐reacts with Bex2 (but not Bex3), and its use to determine the cellular distribution of Bex proteins in the murine brain. The specificity of the antiserum was characterized by immunoprecipitation and Western blots of tissue and transfected cell extracts and by immunocytochemical analyses of cells transfected with either Bex1 or Bex2. Antibodies preabsorbed with Bex2 still recognize Bex1, while blocking with Bex1 eliminates all immunoreactivity to both Bex1 and Bex2. Bex immunoreactivity (ir) was primarily localized to neuronal cells within several regions of the brain, including the olfactory epithelium, bulb, peri/paraventricular nuclei, suprachiasmatic nucleus, arcuate nucleus, median eminence, lateral hypothalamic area, thalamus, hippocampus, and cerebellum. RT‐PCR and in situ hybridization demonstrated the presence of Bex mRNA in several of these regions. Double‐label immunocytochemistry indicates that Bex‐ir is colocalized with OMP in mature olfactory receptor neurons (ORNs) and in the OMP‐positive subpopulation of neurons in hypothalamus. This is the first anatomical mapping of Bex proteins in the mouse brain and their colocalization with OMP in ORNs and hypothalamus. J. Comp. Neurol. 487:1–14, 2005. © 2005 Wiley‐Liss, Inc.
Analysis of the proepicardium–epicardium transition during the malformation of the RXRα−/− epicardium
Authors: Jenkins Shantae J. , Hutson D. Renée , Kubalak Steven W. 
Published: April 2005

AbstractThe epicardium of the heart originates from a cluster of mesothelial‐derived cells that develop beneath the sinus venosus in the embryonic day (E) 9.0–9.5 mouse. The subsequent proepicardium–epicardium transition that forms the epicardial layer of epithelial cells covering the myocardial surface is nearly complete by E10.0–E10.5 and results in a fully covered heart by E11.0. In this study, we show that an established model of congenital heart disease, the retinoid X receptor alpha knockout (RXRα−/−) embryo, displays a malformed epicardium. At E10.0–E10.5, the RXRα−/− has several large regions of myocardium that remain bare. Furthermore, by E11.5–E12.5, when a complete epithelial layer is formed in the mutant, large regions of the epicardium become distended from the underlying myocardium. Close examination of the E9.5 mutant revealed an elevated apoptosis level within the proepicardial cluster of mesothelial cells. Additionally, among the extracellular matrix proteins analyzed, expression of fibronectin was elevated in the RXRα−/− as assessed by immunostaining in paraffin‐embedded sections and proepicardial explants. We propose that these events contribute to a developmental delay in the formation of the epicardium, which leads to an abnormal epicardium and ultimately contributes to the cardiac malformations seen in the RXRα−/−. Developmental Dynamics 233:1091–1101, 2005. © 2005 Wiley‐Liss, Inc.
Embryonic and posthatching development of the barn owl (Tyto alba): Reference data for age determination
Authors: Köppl Christine , Futterer Eva , Nieder Bärbel , Sistermann Ralf , Wagner Hermann 
Published: April 2005

AbstractThe normal development of the barn owl was documented with the intent of providing a guideline for determining the maturational stage of embryos and posthatching individuals. Embryonic development up to stage 39 could be well described using the well‐known developmental atlas for the chicken (Hamburger and Hamilton [1951] J. Morphol. 88:49–92). For later stages, limb size was established as a suitable indicator. In addition, measuring the egg's vascularized area through candling was found to be a useful, noninvasive method for staging very early embryos, up to stage 25. An average relationship between incubation period and embryonic stage was derived, which showed that development in the barn owl initally lags that in the chicken. For posthatching individuals, skeletal measures (tarsal and ulnar length, skull width and length) were the most reliable parameters for judging maturation, up to 1 month. For older individuals, feather development (e.g., length of primary wing feathers) provided the only cue. Developmental Dynamics 233:1248–1260, 2005. © 2005 Wiley‐Liss, Inc.
Cell lineage of primary and secondary enamel knots
Authors: Matalova E. , Antonarakis G.S. , Sharpe P.T. , Tucker A.S. 
Published: April 2005

AbstractRecent research indicates that control of cusp morphology involves a signalling center at the heart of the developing tooth germ, known as the enamel knot. The primary enamel knot forms in both incisors and molar tooth germs at the cap stage of tooth development. Secondary and tertiary enamel knots only develop in molar tooth germs. These sit at the sites of future cusp tips from the early bell stage of tooth development. In studies describing the relationship between the primary and secondary enamel knots, it is often assumed that there is a cellular continuity between these structures, such that cells from the primary enamel knot physically contribute to the secondary enamel knots. We have devised a method whereby the developing tooth germ can be cultured in frontal slices with the enamel knot visible. The fate of the primary enamel knot cells can then be followed by 1,1′, di‐octadecyl‐3,3,3′,3′,‐tetramethylindo‐carbocyanine perchlorate (DiI) labeling. Using this method, no cells of the primary enamel knot were seen to move toward the developing secondary enamel knots. Thus, although the primary and secondary enamel knots have a close molecular and functional relationship in molar development, they are not actually derived from the same cells. Developmental Dynamics 233:754–759, 2005 © 2005 Wiley‐Liss, Inc.
Platinum Complexes with the Novel Ligand Diethyl [(Methylsulfinyl)‐methyl]phosphonate (SMP): Solid‐State Characterization of Potassium Trichloro(SMP)platinum(II) which, in Solution, Gives Dichloro(SMP)‐platinum(II) and Potassium Chloride
Authors: Laforgia Mariarita , Margiotta Nicola , Capitelli Francesco , Bertolasi Valerio , Natile Giovanni 
Published: April 2005

AbstractPhosphonate ligands have been employed in the synthesis of platinum complexes, which are active against bone tumors. The stability of a new compound of this family, [PtCl2(SMP)] {1; SMP = diethyl[(methylsulfinyl)methyl]phosphonate}, has been investigated in water and acetone. The compound is stable in aqueous solution where it undergoes only partial solvolysis that is completely repressed by addition of free chloride ions. However, crystallization of 1 from water/acetone/chloroform (0.2:1:1, v/v/v) containing an equimolar amount of KCl affords a new compound containing monodentate SMP {K[PtCl3(SMP‐S)], 2}. Dissolution of 2 in water or acetone restores 1. The driving force in the formation of 2 appears to be the network of electrostatic interactions between cations and complex anions in the solid state. It is not only the detached P=O oxygen atom, but also the oxygen atom bound to the sulfur atom and a coordinated chloride ligand of the same platinum unit that interact rather strongly with the cation. It is expected that the same reaction (partial detachment of the phosphonate and anchoring of the cation) can take place in hypercalcaemic districts associated to bone tumors. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthetic Explorations Towards Sterically Crowded 1,2,3‐Substituted Bis(indenyl)zirconium(IV) Dichlorides
Authors: Möller Andreas C. , Blom Richard , Heyn Richard H. , Swang Ole , Görbitz Carl‐Henrik , Seraidaris Tanja 
Published: April 2005

AbstractThe systematic synthesis of 1,3‐dialkyl‐substituted 2‐silylindenes and their suitability as zirconocene ligands is discussed. Unexpected reactivities rendered a number of substitution patterns unfeasible, especially for alkyl groups other than methyl in 2‐(trimethylsilyl)indene derivatives, and essentially for all derivatives of 2‐(dimethylsilyl)indene. The syntheses of rac/meso‐bis[1‐methyl‐2‐(trimethylsilyl)indenyl]zirconium(IV) dichloride (12) and bis[1,3‐dimethyl‐2‐(trimethylsilyl)indenyl]zirconium(IV) dichloride (13b) are described. The solid‐state structure of the latter displays strong deformations within the ligand framework and an unusually large Cpcentroid‐Zr–Cpcentroid angle. Both, 12/MAO and 13b/MAO, displayed ethene and ethene‐co‐1‐hexene polymerization activity. Curiously, 13b/MAO shows an extraordinary monomer selectivity, which can be rationalized by means of DFT calculations on the active site. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Self‐Assembly of Protonated 1,12‐Dodecanediamine Molecules and Strongly Undulated Uranyl Selenate Sheets in the Structure of Amine‐Templated Uranyl Selenate: (H3O)2[C12H30N2]3[(UO2)4(SeO4)8](H2O)5
Authors: Krivovichev Sergey V. , Kahlenberg Volker , Avdontseva Evgeniya Yu. , Mersdorf Edgar , Kaindl Reinhard 
Published: April 2005

AbstractThe amine‐templated uranyl selenate (H3O)2[C12H30N2]3[(UO2)4(SeO4)8](H2O)5 (1) has been prepared. Its structure [monoclinic, P21/n, a = 11.3437(7), b = 24.8042(12), c = 29.2496(19) Å, β = 96.701(5)o, V = 8173.8(8) Å3, Z = 4, R1 = 0.083] is based upon strongly undulating [(UO2)(SeO4)2]2– sheets consisting of corner‐sharing UO7 bipyramids and SeO42– tetrahedra. The undulations of the adjacent sheets have an anti‐phase character that allows the formation of large eliptical channels that are occupied by rod micelles formed by self‐assembly of protonated 1,12‐dodecanedi‐amine molecules. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Sediment‐induced stratification in turbulent open‐channel flow
Authors: Ghoshal K. , Mazumder B. S. 
Published: April 2005

AbstractA vertical gradient of suspended sediment concentration exists in a turbulent open channel flow, particularly near the bed where sediment erosion and deposition take place. This shows a remarkable effect on the flow dynamics. The density gradient of sediment‐mixed fluid may become stably stratified, which results in damping of turbulence fluctuations. In this work, theoretical models for mean velocity and concentration distributions have been developed considering the effect of sediment‐induced stratification and the modified mixing length due to high suspension together with viscous and turbulent shear stresses, which are the functions of concentration. The models are compared with comprehensive experimental data sets. The comparison reveals that (i) the calculated velocity and concentration profiles agree well with the observed data, (ii) the model constant due to stratification used for verification is consistent with the measurements in thermally stratified flows, and (iii) the higher the sediment suspension, the better the effect of density stratification and the less the impact of mixing length. Copyright © 2005 John Wiley & Sons, Ltd.
A reference solution for phase change with convection
Authors: Hannoun N. , Alexiades V. , Mai T. Z. 
Published: April 2005

AbstractA reference solutions for phase change involving convection in the melt is currently missing. In the present study, we focus on the problem of melting of pure tin in a square cavity heated from the side, which is used as a benchmark test problem. The mathematical model used for the simulations is based on the enthalpy formulation. Extensive numerical computations are performed with grids as fine as 800 × 800. The convergence of the numerical solution is demonstrated and its level assessed. Data values and plots are provided for use as a reference solution. Copyright © 2005 John Wiley & Sons, Ltd.
Differential roles of XRCC2 in homologous recombinational repair of stalled replication forks
Authors: Liu Nan , Lim Chang‐Su 
Published: April 2005

AbstractHomologous recombination is an important mechanism in DNA replication to ensure faithful DNA synthesis and genomic stability. In this study, we investigated the role of XRCC2, a member of the RAD51 paralog family, in cellular recovery from replication arrest via homologous recombination. The protein expression of XRCC2, as well as its binding partner RAD51D, is dramatically increased in S‐ and G2‐phases, suggesting that these proteins function during and after DNA synthesis. XRCC2 mutant irs1 cells exhibit hypersensitivity to hydroxyurea (HU) and are defective in the induction of RAD51 foci after HU treatment. In addition, the HU‐induced chromatin association of RAD51 is deficient in irs1 mutant. Interestingly, irs1 cells are only slightly sensitive to thymidine and able to form intact RAD51 foci in S‐phase cells arrested with thymidine. Irs1 cells showed increased level of chromatin‐bound RAD51 as well as the wild type cells after thymidine treatment. Both HU and thymidine induce γ‐H2AX foci in arrested S‐phase nuclei. These results suggest that XRCC2 is involved in repair of HU‐induced damage, but not thymidine‐induced damage, at the stalled replication forks. Our data suggest that there are at least two sub‐pathways in homologous recombination, XRCC2‐dependent and ‐independent, for repair of stalled replication forks and assembly of RAD51 foci following replication arrest in S‐phase. © 2005 Wiley‐Liss, Inc.
Regulation of androgen receptor levels: Implications for prostate cancer progression and therapy
Authors: Burnstein Kerry L. 
Published: April 2005

AbstractAndrogen deprivation has been the standard therapy for advanced and metastatic prostate cancer for over half a century, as prostate tumors are initially dependent on androgens for growth and survival. Unfortunately, in most patients undergoing androgen ablation, relapse (recurrent tumor growth) eventually occurs. The actions of the principal androgens, testosterone and dihydrotestosterone (DHT), are mediated via androgen receptors (ARs), ligand‐activated transcription factors that belong to the nuclear receptor superfamily. Because of the presence of transcriptionally active ARs in tumors from recurrent or androgen‐independent disease, there is a heightened interest in new therapeutic paradigms that target the AR and its regulatory pathways. The regulation of AR levels is highly complex with control exerted by several pathways and in a cell‐, tissue‐, and developmental‐stage specific manner. Androgens are important regulators of AR mRNA and protein through transcriptional and post‐transcriptional mechanisms. This article reviews the evidence implicating the AR in recurrent prostate cancer and discusses the multiple mechanisms that regulate AR levels in normal and neoplastic cells. The complexity of AR regulation suggests that there will be an ample array of potential new drug targets for modulating levels of this receptor, a key signaling molecule in prostate cancer. © 2005 Wiley‐Liss, Inc.
Major contribution of the multidrug transporter P‐glycoprotein to reduced susceptibility of poly(ADP‐ribose) polymerase‐1 knock‐out cells to doxorubicin action
Authors: Węsierska‐Gądek Józefa 
Published: April 2005

AbstractInactivation of poly(ADP‐ribose) polymerase‐1 (PARP‐1) has been shown to potentiate the cytotoxicity of distinct DNA targeting agents including topoisomerase I inhibitors. On the other hand, the PARP‐1 deficient cells exhibited resistance to conventional inhibitors of topoisomerase II such as etoposide or doxorubicin (DOX). Recently, we observed the extreme sensitivity of PARP‐1 knock‐out (KO) cells to C‐1305, a new biologically active triazoloacridone compound. C‐1305 permanently arrested the cells in G2‐phase of the cell‐cycle. These observations prompted us to investigate more thoroughly the susceptibility of PARP‐1 KO cells to DOX and to examine the effect of DOX on the progression of cell‐cycle. We determined the uptake of DOX and P‐glycoprotein (P‐gp) expression in mouse cells and compared it with that in human myeloma 8226/Dox40 cells overexpressing P‐gp. Exposure of mouse cells to DOX revealed a reduced drug uptake in cells lacking PARP‐1. However, combined treatment with verapamil, a potent MDR modulator increased the DOX accumulation. Detailed immunoblotting experiments revealed an approximately threefold higher P‐gp level in PARP‐1 KO cells as compared with normal counterparts. Interestingly, DOX induced in normal fibroblasts very rapidly G2 arrest whereas in PARP‐1 KO cells it blocked primarily the transition between S and G2 resulting in the increase of cells remaining in S‐phase. This coincided with the lack of the site‐specific phosphorylation of CDK2. Simultaneous inhibition of P‐gp in cells lacking PARP‐1 resulted in an accumulation of cells in G2. Exposure of mouse cells to high DOX dose activated significantly caspase‐3/7 in PARP‐1 KO cells. © 2005 Wiley‐Liss, Inc.
Mammalian Groucho homologs: Redundancy or specificity?
Authors: Gasperowicz Malgorzata , Otto Florian 
Published: April 2005

AbstractThe proteins termed TLE in humans, Grg in mice and Groucho in Drosophila constitute a family of transcriptional corepressors. In mammalians there are five different genes encoding an even larger number of proteins. Interactions between these TLE/Grg proteins and an array of transcription factors has been described. But is there any specificity? This review tries to make a case for a non‐redundant function of individual TLE/Grg proteins. The specificity may be brought about by a tightly controlled temporo‐spatial expression pattern, post‐translational modifications, and subtle structural differences leading to distinct preferences for interacting transcription factors. A confirmation of this concept will ultimately need to come from genetic experiments. © 2005 Wiley‐Liss, Inc.
Effects of Electron Donors on Active Sites Distribution of MgCl2‐Supported Ziegler‐Natta Catalysts Investigated by Multiple Active Sites Model
Authors: Wang Qi , Murayama Namiko , Liu Boping , Terano Minoru 
Published: April 2005

AbstractSummary: The stopped‐flow polymerization of propylene catalyzed by a Ziegler‐Natta catalyst in the presence of internal and external electron donors was carried out. The influence of the electron donors on the active sites of the catalyst was investigated using a multiple active site model. The variation of each group of active sites, such as the concentration and kp of each site at various polymerization times, can be obtained from this model. It was found that an electron donor mainly affects the aspecific active site by reducing its concentration and increasing its kp. The isospecific site is only slightly altered in terms of concentration and its kp because of steric hindrance.Variation of [C*] of each active site of TiCl4/MgCl2‐AlEt3 at various polymerization times.imageVariation of [C*] of each active site of TiCl4/MgCl2‐AlEt3 at various polymerization times.