bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression and functional analysis of genes deregulated in mouse placental overgrowth models: Car2 and Ncam1
Authors: Singh Umashankar , Sun Tong , Shi Wei , Schulz Ralph , Nuber Ulrike A. , Varanou Aikaterini , Hemberger Myriam C. , Elliott Rosemary W. , Ohta Hiroshi , Wakayama Teruhiko , Fundele Reinald 
Published: October 2005

AbstractDifferent causes, such as maternal diabetes, cloning by nuclear transfer, interspecific hybridization, and deletion of some genes such as Esx1, Ipl, or Cdkn1c, may underlie placental overgrowth. In a previous study, we carried out comparative gene expression analysis in three models of placental hyperplasias, cloning, interspecies hybridization (IHPD), and Esx1 deletion. This study identified a large number of genes that exhibited differential expression between normal and enlarged placentas; however, it remained unclear how altered expression of any specific gene was related to any specific placental phenotype. In the present study, we focused on two genes, Car2 and Ncam1, which both exhibited increased expression in interspecies and cloned hyperplastic placentas. Apart from a detailed expression analysis of both genes during normal murine placentation, we also assessed morphology of placentas that were null for Car2 or Ncam1. Finally, we attempted to rescue placental hyperplasia in a congenic model of IHPD by decreasing transcript levels of Car2 or Ncam1. In situ analysis showed that both genes are expressed mainly in the spongiotrophoblast, however, expression patterns exhibited significant variability during development. Contrary to expectations, homozygous deletion of either Car2 or Ncam1 did not result in placental phenotypes. However, expression analysis of Car3 and Ncam2, which can take over the function of Car2 and Ncam1, respectively, indicated a possible rescue mechanism, as Car3 and Ncam2 were expressed in spongiotrophoblast of Car2 and Ncam1 mutant placentas. On the other hand, downregulation of either Car2 or Ncam1 did not rescue any of the placental phenotypes of AT24 placentas, a congenic model for interspecies hybrid placentas. This strongly suggested that altered expression of Car2 and Ncam1 is a downstream event in placental hyperplasia. Developmental Dynamics 234:1034–1045, 2005. © 2005 Wiley‐Liss, Inc.
Asymmetric Organocatalysis with Novel Chiral Thiourea Derivatives: Bifunctional Catalysts for the Strecker and Nitro‐Michael Reactions
Authors: Tsogoeva Svetlana B. , Yalalov Denis A. , Hateley Martin J. , Weckbecker Christoph , Huthmacher Klaus 
Published: October 2005

AbstractNovel bifunctional organocatalysts bearing both a thiourea moiety and an imidazole group on a chiral scaffold were synthesized and applied to the Strecker synthesis and nitro‐Michael reaction. The addition of acetone to nitroolefins in the presence of these novel bifunctional organocatalysts gave enantioselectivities (up to 87 % ee) that are superior to those generated by the proline and/or homo‐proline tetrazole catalysts described in the literature. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
A General Study of Aryloxo and Alkoxo Ligands in the Titanium‐Catalyzed Intermolecular Hydroamination of Terminal Alkynes
Authors: Tillack Annegret , Khedkar Vivek , Jiao Haijun , Beller Matthias 
Published: October 2005

AbstractA general study of the regioselective hydroamination of terminal alkynes in the presence of Ti(NEt2)4 and different aryloxo and alkoxo ligands is presented. Depending on the ligand the regioselectivity towards the Markovnikov and the anti‐Markovnikov addition product can be controlled. The experimentally observed isomer distribution is explained perfectly by detailed theoretical investigations which demonstrate that the regioselectivity is determined by the relative stability of the corresponding alkynetitanium π complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Cerium‐Catalyzed, Aerobic Oxidative Synthesis of 1,2‐Dioxane Derivatives from Styrene and Their Fragmentation into 1,4‐Dicarbonyl Compounds
Authors: Rössle Michael , Werner Thomas , Frey Wolfgang , Christoffers Jens 
Published: October 2005

Abstract1,4‐Diketones were prepared by cerium‐catalyzed oxidative coupling of styrene with molecular oxygen and 1,3‐dicarbonyl compounds. This two‐step sequence was performed as a one‐pot procedure without isolation of the intermediate products. The first step is a metal‐catalyzed radical reaction yielding 3‐hydroxy‐1,2‐dioxane derivatives being the cyclotautomers of initially formed 4‐hydroperoxy ketones. In the second step of this sequence, these endoperoxides are converted with AcCl–pyridine by Kornblum–DeLaMare fragmentation into the 1,4‐dicarbonyl motif. Several intermediate 1,2‐dioxane derivatives could be isolated and structurally characterized by X‐ray crystallography. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis of Dihydrofurans Substituted in the 2‐Position
Authors: Kilroy Timothy G. , O'Sullivan Timothy P. , Guiry Patrick J. 
Published: October 2005

AbstractMany natural products and biologically active compounds contain the dihydrofuran subunit. Molecules incorporating either 2‐substituted, 2,2‐disubstituted 2,3‐ or 2,5‐dihydrofurans are widespread in the literature and represent key “molecular building blocks”. The preparation of substituted dihydrofurans remains a current challenge in organic synthesis and this microreview details the various routes employed for their synthesis in the literature to the end of 2004. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis and Properties of New Nucleotide Analogues Possessing Squaramide Moieties as New Phosphate Isosters
Authors: Seio Kohji , Miyashita Takuhei , Sato Kousuke , Sekine Mitsuo 
Published: October 2005

AbstractNew analogues of 2′‐deoxynucleotides and ribonucleotides incorporating a unique squaramide structure were synthesized. Because of the strong acidity of this moiety (pKa = 2.3), these nucleotide analogues exist in a monoanionic form, which can be regarded as an electronic isoster of 5′‐nucleotides under physiological conditions. The synthesis of the nucleotide analogues was achieved through the condensation of 5′‐ or 3′‐aminonucleosides with dimethyl squarate, whilst the selective removal of the methyl group was effectively accomplished by treatment with sodium bromide. In addition, we also synthesized 3′,5′‐cyclic nucleotide analogues from the 3′,5′‐diazidonucleoside derivatives. NMR analysis revealed that their ribose puckering was of an N‐type form, identical to that in cAMP and cGMP. Because of the unique structural, electronic, and conformational properties of squaramide‐type nucleotide analogues, these analogues should be quite interesting as potential biologically active compounds such as antiviral and anticancer agents. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Spin–Spin Interactions Across the “Cove” in the (Z) and (E) Isomers of 1,1′‐Difluoro‐9,9′‐bifluorenylidene
Authors: Krcsmar Lidia , Grunenberg Jörg , Dix Ina , Jones Peter G. , Ibrom Kerstin , Ernst Ludger 
Published: October 2005

AbstractIn the (Z) isomer, but not in the (E) isomer of title compound 1, moderate 19F,19F spin–spin coupling across the “cove” is observed [J(F,F) = 11.0 Hz], which is deemed to obey a through‐space mechanism. The coupling between the isochronous fluorine nuclei of 1Z causes second‐order effects in the 1H, 13C and 19F NMR spectra of this compound and allows its easy distinction from the (E) isomer. A B3LYP/6‐31+G(d) calculation of 1Z as an isolated molecule was carried out which gave a non‐bonded F,F distance d(F,F) of 2.711 Å and an angle between the two C–F bond vectors of 34.1°. The computed F···F compliance constant of 6.96 Å/mdyn points to a very weak interaction. According to our previous correlation between d(F,F) and through‐space J(F,F), the F,F distance in 1Z would be expected to go along with a coupling constant of ca. 46 Hz. This discrepancy between prediction and experiment gives support to our earlier presumption that a simple d(F,F)/J(F,F) correlation may not sufficiently describe through‐space couplings and that an angular factor should also be taken into account. An X‐ray diffraction study of 1Z resulted in an F,F distance of 2.638 Å and an angle between the C–F bonds of 36.4°, in fair agreement with the MO calculation. The rigidity of the (Z) isomer was studied using theoretical compliance constants. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Bismuth Triflate Catalyzed Mukaiyama Aldol Reaction in an Ionic Liquid
Authors: Ollevier Thierry , Desyroy Valerie , Debailleul Blandine , Vaur Sophie 
Published: October 2005

AbstractWe have developed an efficient, bismuth triflate catalyzed Mukaiyama aldol reaction. The reaction proceeds rapidly and affords the corresponding β‐hydroxy carbonyl compound in moderate to very good yields (up to 92 %). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Electrochemical Evaluation of Nucleoside Analogue Lamivudine in Pharmaceutical Dosage Forms and Human Serum
Authors: Dogan Burcu , Uslu Bengi , Suzen Sibel , Ozkan Sibel A. 
Published: October 2005

AbstractLamivudine (LAM) is a synthetic nucleoside analogue with activity against human immunodeficiency virus‐type 1 (HIV‐1) and Hepatitis B virus (HBV). The aim of this study was to determine LAM levels in serum and pharmaceutical formulations, by means of electrochemical methods using hanging mercury drop electrode (HMDE). On this electrode, LAM undergoes irreversible reduction at the peak potential near Ep−1.26 V (vs. Ag/AgCl/3 M KCl). Reduction LAM signals were measured by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and square‐wave voltammetry (OSW). DPV and OSW techniques for the determination of LAM in acetate buffer at pH 4.5, which allows quantitation over the 4×10−6 to 1×10−4 M range in supporting electrolyte for both methods, were proposed. The linear response was obtained in acetate buffer in the ranges of 2×10−6 to 2×10−4 M for spiked serum samples at pH 4.5 for both techniques. The repeatability and reproducibility of the methods for all media were determined. The standard addition method was used in serum. Precision and accuracy were also checked in all media. No electroactive interferences from the endogenous substances were found in serum. With respect to side effects of high doses and short half‐life of LAM, a fast and simple detection method is described in this study.
Highly Thiocyanate‐Selective PVC Membrane Electrode Based on Lipophilic Ferrocene Derivative
Authors: Dai Jianyuan , Yuan Ruo , Chai Yaqin , An Lanxiang , Zhong Xia , Liu Yan , Tang Dianping 
Published: October 2005

AbstractA novel anion‐selective PVC membrane electrode based on bis‐[(3‐ferrocenyl)‐(2‐crotonic acid)] copper(II) complex [Cu(II)‐BFCA] as neutral carrier is described, which demonstrates excellent potentiometric response characteristics toward thiocyanate ion and anti‐Hofmeister selectivity sequence in following order: SCN−>I−>ClO$\rm{ {_{4}^{-}}}$>Sal−>Br−>NO$\rm{ {_{3}^{-}}}$>Cl−≈NO$\rm{ {_{2}^{-}}}$>SO$\rm{ {_{3}^{2-}}}$>SO$\rm{ {_{4}^{2-}}}$. The electrode shows a near‐Nernstian response for thiocyanate ion in a wide range of 9.0×10−7–1.0×10−1 M with a detection limit 6.8×10−7 M and a slope of −59.1 mV/decade in pH 5.0 of phosphate buffer solution at 20 °C. The influences of lipophilic cationic and anionic additives on the response properties of the electrode were investigated. High sensitivity and wide linear dynamic range were observed for the electrode in the presence of hexadecyltrimethylammoniumborate (HTAB) as a lipophilic cationic additive. The electrode was successfully applied to the determination of thiocyanate ion in waste water and human saliva.
Suspended sediment load estimation and the problem of inadequate data sampling: a fractal view
Authors: Sivakumar Bellie 
Published: October 2005

AbstractSuspended sediment load estimation at high resolutions is an extremely difficult task, because: (1) it depends on the availability of high‐resolution water discharge and suspended sediment concentration measurements, which are often not available; (2) any errors in the measurements of these two components could significantly influence the accuracy of suspended sediment load estimation; and (3) direct measurements are very expensive. The purpose of this study is to approach this sampling problem from a new perspective of fractals (or scaling), which could provide important information on the transformation of suspended sediment load data from one scale to another. This is done by investigating the possible presence of fractal behaviour in the daily suspended sediment load data for the Mississippi River basin (at St. Louis, Missouri). The presence of fractal behaviour is investigated using five different methods, ranging from general to specific and from mono‐fractal to multi‐fractal: (1) autocorrelation function; (2) power spectrum; (3) probability distribution function; (4) box dimension; and (5) statistical moment scaling function. The results indicate the presence of multi‐fractal behaviour in the suspended sediment load data, suggesting the possibility of transformation of data from one scale to another using a multi‐dimensional model. Copyright © 2005 John Wiley & Sons, Ltd.
Valeric acid extraction with tri‐n‐butyl phosphate impregnated in a macroporous resin: II. Studies in fixed bed columns
Authors: Ruiz Maria Olga , Cabezas José Luis , Escudero Isabel , Coca José 
Published: October 2005

AbstractExtraction and back‐extraction of valeric acid in a fixed bed packed with Amberlite XAD‐4 resin impregnated with tri‐n‐butyl phosphate were experimentally studied at 25 °C. The effects of the feed flow rate, acid concentration in the feed solution and extractant concentration in the impregnated resin on the breakthrough curves, were investigated. The bed saturation capacity was larger under the conditions of higher extractant concentration in the resin phase and higher acid concentration in the feed solution. A dynamic model that considers intraparticle diffusion and external liquid film diffusion as limiting steps in mass transfer rates was successfully applied. The intraparticle effective diffusivities (10−9 dm2 s−1) were from one to three orders of magnitude lower than the diffusivities in the external liquid film (10−8–10−6 dm2 s−1). A fast and complete back‐extraction of valeric acid from the saturated bed was carried out with sodium hydroxide solutions. The operational life of the impregnated resin was also studied. Copyright © 2005 Society of Chemical Industry
Full‐scale in situ bioremediation of hexachlorocyclohexane‐contaminated soil
Authors: Phillips Theresa M , Lee Hung , Trevors Jack T , Seech Alan G 
Published: October 2005

AbstractDaramend bioremediation technology was used to treat 1100 tonnes of hexachlorocyclohexane (HCH)‐contaminated soil at a former lindane manufacturing plant. Half of the site (area A) was treated using a cycled anoxic/oxic treatment, and the other half (area B) was treated under oxic conditions. Each area was divided east to west into five zones. A control area (area C) consisted of strips of soil along the north and east edges of the site. Total HCH concentrations along a west to east gradient ranged from 22 430 to 1069 mg kg−1 in area A and from 21 100 to 730 mg kg−1 in area B. Concentrations in area C ranged from 52 to 1427 mg kg−1. The soil was treated for 371 days, during which time seven anoxic/oxic cycles were completed in area A and regular tillage was performed on area B. Soil samples (one per zone) were collected after 154 and 371 days of treatment. After 371 days, total HCH concentrations were reduced in the most highly contaminated zones of areas A and B by 60% (from 22 430 to 8910 mg kg−1) and 75% (from 21 100 to 5120 mg kg−1), respectively. The average HCH reductions for all five zones of areas A and B were 40 and 47%, respectively, with the data indicating decreased concentrations of selected isomers in certain zones of both areas. Less substantial changes in HCH concentrations were observed in control area C. Elevated chloride ion concentrations were observed in zones that had demonstrated HCH removal. This full scale project demonstrated the potential for solid phase bioremediation treatment of soil containing high HCH concentrations. Copyright © 2005 Society of Chemical Industry
Detoxification of synthetic industrial wastewaters using electrochemical oxidation with boron‐doped diamond anodes
Authors: Cañizares Pablo , Sáez Cristina , Lobato Justo , Rodrigo Manuel A 
Published: October 2005

AbstractThe electrochemical oxidation on boron‐doped diamond (BDD) anodes of synthetic industrial wastewaters polluted with different aromatic compounds has been studied. This technology reduces significantly the organic load and the toxicity of treated aqueous wastes. The shape of the toxicity vs time curve depends strongly on the nature of the phenolic compounds, and especially on the substituent groups contained in the phenol molecule. For the oxidation of hydroxybenzenes a complex shape is obtained, with a plateau zone in the first stages of the electrolyses. This plateau zone is transformed into a maximum in the electrolyses of chlorophenols. In the case of nitrophenols, the toxicity index decreases at the same time as the chemical oxygen demand (COD) concentration, although the decrease in the toxicity is less significant than the decrease in the COD. All these toxicity profiles can be justified in terms of the nature of the intermediates generated during the electrolyses, but they cannot be directly related to the COD variation, which shows an exponential decrease. Copyright © 2005 Society of Chemical Industry
Optimized lipopolyplex formulations for gene transfer to human colon carcinoma cells under in vitro conditions
Authors: Pelisek Jaroslav , Gaedtke Lars , DeRouchey Jason , Walker Greg F. , Nikol Sigrid , Wagner Ernst 
Published: October 2005

AbstractBackgroundPolycation (PC, polyplex), cationic lipid (CL, lipoplex), and a combination of PC/CL (lipopolyplex) formulations were investigated for gene transfer to slow‐proliferating human colon carcinoma cell lines (COGA).MethodsThe luciferase reporter gene was complexed with either PC, CL, or PC/CL. PCs included linear (PEI22lin, 22 kDa) and branched polyethylenimine (PEI2k, 2 kDa; PEI25br, 25 kDa) and poly‐L‐lysine (PLL18 with 18 lysine monomers). CLs included DOCSPER, DOSPER and DOTAP. Lipopolyplexes were formed by either sequentially first mixing DNA with PC or CL, followed by addition of CL or PC, respectively, or simultaneously with both PC and CL. Particle size and zeta‐potential were determined and gene transfer and cytotoxicity were quantified on COGA‐3, ‐5, ‐12, HeLa and Sw480 cells.ResultsThe highest gene transfer was achieved when DNA was first complexed with PC followed by CL. At low ionic strength, particles were small (50–130 nm) with a zeta‐potential of +20–40 mV. At physiological ionic strength, only lipoplexes of DOCSPER or DOSPER and their respective lipopolyplexes with PEI25br were stable to aggregation (140–220 nm). Lipopolyplexes of PEI25br were between 5‐ to 400‐fold more efficient compared to the corresponding lipoplexes or polyplexes in all cases. Chloroquine did not significantly affect lipopolyplex‐mediated gene transfer.ConclusionsLipopolyplex formulations of PEI25br in combination with multivalent CLs (DOCSPER, DOSPER) are promising tools for in vitro and potentially also in vivo gene transfer to colorectal cancer cells. Copyright © 2005 John Wiley & Sons, Ltd.
Ambient mass spectrometry using desorption electrospray ionization (DESI): instrumentation, mechanisms and applications in forensics, chemistry, and biology
Authors: Takáts Zoltán , Wiseman Justin M. , Cooks R. Graham 
Published: October 2005

AbstractAnalytical characteristics of DESI are summarized. Examples of applications to small and large molecules, to in situ analysis, and to high‐throughput analyses are presented. Evidence is provided for both a heterogeneous charge‐transfer mechanism and a droplet pick‐up mechanism of ionization. The speed, lack of the need for sample preparation, selectivity, and sensitivity of DESI are all demonstrated and discussed. Instrumentation is also discussed. Forensic applications as well as emerging areas of application including tissue imaging are given emphasis. Copyright © 2005 John Wiley & Sons, Ltd.
Lipopolysaccharide and proinflammatory cytokines require different astrocyte states to induce nitric oxide production
Authors: Kozuka Nagisa , Itofusa Rurika , Kudo Yoshihisa , Morita Mitsuhiro 
Published: October 2005

AbstractNitric oxide (NO) production by astrocytes is a significant factor affecting brain physiology and pathology, but the mechanism by which it is regulated is not known. Previous studies using different specimens and stimuli might have described different aspects of a complex system. We investigated the effect of culture and stimulus conditions on NO production by cultured astrocytes and identified two combinations of these allowing NO production. Lipopolysaccharide (LPS)‐induced NO production required a high seeding cell density and was independent of the serum concentration, whereas that induced by proinflammatory cytokines required simultaneous treatment with interleukin‐1β, tumor necrosis factor‐α, and interferon‐γ and low‐serum conditions but was less affected by the seeding density. These two pathways showed differential sensitivity to protein kinase inhibitors. Both LPS and cytokines induced expression of inducible nitric oxide synthase (iNOS). Although LPS‐induced iNOS expression required a high seeding cell density, cytokine‐induced iNOS expression, in contrast to NO production, was not affected by the serum concentration. These results suggest that astrocytes interact with the environment and alter their responsiveness to NO production‐inducing stimuli by regulating iNOS expression and activity. This is the first evidence for the selective use of two different regulatory pathways in any cell type. © 2005 Wiley‐Liss, Inc.
Ischemic preconditioning ameliorates excitotoxicity by shifting glutamate/γ‐aminobutyric acid release and biosynthesis
Authors: Dave Kunjan R. , Lange‐Asschenfeldt Christian , Raval Ami P. , Prado Ricardo , Busto Raul , Saul Isabel , Pérez‐Pinzón Miguel A. 
Published: October 2005

AbstractExcitotoxicity is recognized to play a major role in cerebral ischemia‐induced cell death. The main goal of the present study was to define whether our model of ischemic preconditioning (IPC) promotes a shift from excitatory to inhibitory neurotransmission during the test ischemia to diminish metabolic demand during the reperfusion phase. We also determined whether γ‐aminobutyric acid (GABA) played a role in IPC‐induced neuroprotection. Ten minutes of cerebral ischemia was produced by tightening the carotid ligatures bilaterally following hypotension. Samples of microdialysis perfusate, representing extracellular fluid, were analyzed for amino acid content by HPLC. IPC promoted a robust release of GABA after lethal ischemia compared with control rats. We also observed that the activity of glutamate decarboxylase (the predominant pathway of GABA synthesis in the brain) was higher in the IPC group compared with control and ischemic groups. Because GABAA receptor up‐regulation has been shown to occur following IPC, and GABAA receptor activation has been implicated in neuroprotection against ischemic insults, we tested the hypothesis that GABAA or GABAB receptor activation was neuroprotective during ischemia or early reperfusion by using an in vitro model (organotypic hippocampal slice culture). Administration of the GABAB agonist baclofen during test ischemia and for 1 hr of reperfusion provided significant neuroprotection. We concluded that increased GABA release in preconditioned animals after ischemia might be one of the factors responsible for IPC neuroprotection. Specific activation of GABAB receptor contributes significantly to neuroprotection against ischemia in organotypic hippocampal slices. © 2005 Wiley‐Liss, Inc.