bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Synthetic Approach Towards Interlocked π‐Conjugated Macrocycles
Authors: Ammann Martin , Rang Alexander , Schalley Christoph A. , Bäuerle Peter 
Published: February 2006

AbstractA method for the synthesis of interlocked π‐conjugated macrocycles is described. Starting from 2,9‐bis(oligothienyl)[1,10]phenanthrolines, (trimethylsilyl)acetylene groups were introduced at the terminal thiophene rings by selective iodination and subsequent Sonogashira–Hagihara coupling. Subsequently, we applied our recently developed metal‐template approach to macrocyclization reactions by treating the deprotected acetylenes with cis‐[Pt(dppp)Cl2] to yield a platina‐macrocycle. Based on this synthetic knowledge, by a multiple transition‐metal‐template protocol we accomplished the synthesis of a copper(I)–catenate consisting of two interlocked π‐conjugated macrocycles which contain oligothiophene, diacetylene and phenanthroline units. Conclusive evidence for the new structures came from a detailed characterization of the platina‐macrocycles and catenates by ESI‐FT‐ICR and tandem mass spectrometry experiments. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Numerical Simulation of the Effects of Experimental Error on the Higher Harmonic Components of Fourier Transformed AC Voltammograms
Authors: Gavaghan D. J. , Bond A. M. 
Published: February 2006

AbstractIn this simulation study we investigate the effects of realistic levels of random and systematic experimental error in higher harmonics detected by Fourier transformed AC voltammetry for a reversible process. We show that by analyzing in the frequency domain results that are collected in the time domain, we can achieve a very large reduction in the magnitude of random (Gaussian) noise, and complete elimination of the systematic error introduced by mains frequency in both the small and large amplitude cases. As a consequence, we confirm experimental observations that even the eighth harmonic for a reversible process can be readily detected in the presence of very significant noise levels when 100 mV amplitude sine wave perturbations are employed.
Reference Electrode for Ionic Liquids
Authors: Saheb Amir , Janata Jiří , Josowicz Mira 
Published: February 2006

AbstractReference electrodes for room temperature ionic liquid (RTIL) applications were constructed that have a known and reproducible potential versus the ferrocene/ferrocenium couple. They are based on reference electrodes of the first kind, Ag/Ag+ couple type, or of the second kind, based on Ag/AgCl in M+Cl−. The former uses AgNO3 salt and the latter tetrabutylammonium chloride, Bu4NCl, dissolved in acetonitrile which are then introduced to the ionic liquid of choice for a final concentration of 0.1 M. The reference electrodes can be easily and reproducibly constructed. An ionic contact of these reference systems with the test electrolyte was made using an asbestos fiber liquid junction. The internal compartment of the reference system was filled with the same ionic liquid as used for the electrochemical experiment. The performance of these reference electrodes was tested in selected ionic liquids using the ferrocene/ferrocenium redox couple. The stability, reproducibility, and temperature behavior of the two reference systems have been characterized in the following ionic liquids: 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BMIBF4), 1‐butyl‐3‐methylimidazolium bis(trifluoromethanesulfonyl)imide (BMI(CF3SO2)2N), and 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMIPF6). It has been found that the formal potentials of the examined reference systems are stable over several days. There is a linear relationship for the temperature studied in the range from 25 to 60 °C.
Toll‐like receptor 3 on adult human astrocytes triggers production of neuroprotective mediators
Authors: Bsibsi Malika , Persoon‐Deen Carla , Verwer Ronald W.H. , Meeuwsen Sonja , Ravid Rivka , Van Noort Johannes M. 
Published: February 2006

AbstractToll‐like receptors (TLRs) are innate immunity receptors that are expressed on a wide range of cell types, including CNS glial cells. In general, TLR engagement by specific sets of microbial ligands triggers production of pro‐inflammatory factors and enhances antigen‐presenting cell functions. The functional roles of TLR in the CNS, however, are still poorly understood. While adult human astrocytes in culture dominantly express TLR4, they display a strikingly strong and selective induction of TLR3 when activated by pro‐inflammatory cytokines, TLR3 or TLR4 agonists, or oxidative stress. Gene profiling analysis of the astrocyte response to either TLR3 or TLR4 activation revealed that TLR3, but not TLR4, induces expression of a range of neuroprotective mediators and several other molecules that regulate cellular growth, differentiation, and migration. Also, TLR3 triggered enhanced production of anti‐inflammatory cytokines including interleukin‐9 (IL‐9), IL‐10, and IL‐11 and downregulation of the p40 subunit of IL‐12 and IL‐23. The collective TLR3‐induced products were found in functional assays to inhibit astrocyte growth, promote human endothelial cell growth, and importantly, to enhance neuronal survival in organotypic human brain slice cultures. Together, our data indicate that TLR3 is induced on human astrocytes upon inflammation and when activated, mediates a comprehensive neuroprotective response rather than a polarized pro‐inflammatory reaction. © 2006 Wiley‐Liss, Inc.
Tumor–stromal interactions reciprocally modulate gene expression patterns during carcinogenesis and metastasis
Authors: Montel Valérie , Mose Evangeline Sari , Tarin David 
Published: February 2006

AbstractThis study used a unique xenogeneic breast cancer model to study the effects of tumor cells and neighboring host cells upon each other in tumor growth and metastasis. It exploited species differences between the interacting components to determine how the host influenced the tumor and vice versa. It was found that the gene expression profiles of highly and poorly metastatic clones from the same human breast carcinoma changed differentially when the cells were transferred from growth in vitro to the mammary gland. We describe novel sets of genes, validated by human‐specific probes, which were induced in the 2 isogenic, but phenotypically different, tumor lineages by the mammary environment. Conversely, the tumor cells also induced changes in gene expression in the neighboring host stromal (i.e., mesenchymal) cell lineages, validated by mouse‐specific probes. Reciprocal inductive interactions were also demonstrated in the tumor deposits formed preferentially in the lungs and lymph nodes by the highly metastatic tumor cells. Subtraction of the induced gene changes in the primary site from those in the metastases revealed that the number and magnitude of specific gene inductions in colonized organs were moderate. This finding indicates that the gene expression program causing metastasis has only limited flexibility and fits well with clinical observations that tumor cells form metastases preferentially in select organs, although tumor cells are scattered ubiquitously. This dependency on suitable host niches suggests new molecular therapeutic avenues that target genes in the host‐support system that is manipulated by the malignant cells. © 2006 Wiley‐Liss, Inc.
Distribution of Trichoptera communities in the Hozgargantacatchment (Los Alcornocales Natural Park, SW Spain)
Authors: Ruiz García Antonio , Herrera Grao Antonio F. , Ferreras‐Romero Manuel 
Published: February 2006

AbstractThe distribution of Trichoptera of the Hozgarganta River (Los Alcornocales Natural Park, SW Spain) in relation with environmental factors was examined.Three groups of species were recognised according to the altitudinal gradient. In the headwaters the caddisflies Rhyacophila fonticola, Lepidostoma hirtum, Silonella aurata, Allogamus gibraltaricus, Hydropsyche infernalis and Diplectrona felix predominated; in the constrained section of the tributaries Polycentropus kingi, Chimarra marginata, Hydropsyche iberomaroccana, R. fonticola and Tinodes sp. prevailed; finally, in the main channel H. iberomaroccana, C. marginata, Hydropsyche lobata, Leptocerus lusitanicus and Rhyacophila munda were the most important species. A direct ordination analysis (CCA) was used to describe assemblage changes among sites and corroborated that conductivity and temperature were the variables that best explained Trichoptera distribution.The temporal analysis showed changes in the Trichoptera diversity and richness in permanent stretches, as well as variations in the structure of the communities according to the season. We identified autumn‐winter species (H. infernalis, H. siltalai, H. lobata, R. fonticola and R. munda ) and summer ones (Ithytrichia sp, Oxyethira unidentata, Mystacides azurea and Setodes argentipunctellus ). In the basin we distinguished permanent, intermittent and ephemeral reaches with similar caddisfly richness and diversity, however the species composition associated with each one was different. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Seasonal Dynamics of Picocyanobacteria and Picoeukaryotes in a Large Shallow Lake (Lake Balaton, Hungary)
Authors: Mózes Andrea , Présing Mátyás , Vörös Lajos 
Published: February 2006

AbstractThe abundance and composition of autotrophic picoplankton (APP) were studied between February 2003 and March 2004 in Lake Balaton. Water samples were taken fortnightly in the eutrophic western basin and mesotrophic eastern basin. Our study, which took more than one year, revealed pronounced seasonal pattern of the picoplankton abundance and composition. According to our results there were three types of picoplankton in Lake Balaton: 1. Phycoerythrin‐rich coccoid cyanobacteria (PE), dominant summer picoplankters in the mesotrophic lake area; 2. Phycocyanin‐rich cyanobacteria (PC), the most abundant summer picoplankters in the eutrophic lake area; 3. Picoeukaryotes, dominant winter picoplankters in the whole lake. The observed abundance of picoeukaryotes (3 × 105 cells ml–1) was one of the highest ever found. Our study confirms that in Lake Balaton the colonial autotrophic picoplankton (colonial APP) become dominant in summer in the nutrient limited period. We have found strong negative relationship between the concentrations of available nitrogen forms (NH4–N, NO3–N, urea‐N) and the colonial APP abundance. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of gel properties on neocartilage formation by auricular chondrocytes photoencapsulated in hyaluronic acid networks
Authors: Chung Cindy , Mesa John , Randolph Mark A. , Yaremchuk Michael , Burdick Jason A. 
Published: February 2006

AbstractThe objective of this study was to determine how changes in the network structure and properties of hyaluronic acid (HA) hydrogels, due to variations in the macromer molecular weight (50–1100 kDa) and macromer concentration (2–20 wt %), affect neocartilage formation by encapsulated auricular chondrocytes. To investigate tissue formation, swine auricular chondrocytes were photoencapsulated in the various networks, implanted subcutaneously in the dorsum of nude mice, and explanted after 6 and 12 weeks for biochemical and histological analysis. After 12 weeks, the various constructs were 81–93% water, contained between 0.1 × 106 and 0.6 × 106 chondrocytes per sample, and consisted of 0–0.049 μg chondroitin sulfate/μg wet weight (glycosaminoglycan (GAG) content) and 0.002–0.060 μg collagen/μg wet weight. Histological staining showed an even distribution of chondrocytes and GAGs in addition to minimal type I collagen staining and intense and uniform type II collagen staining in the constructs with greatest neocartilage production. Hydrogels fabricated from 2 wt % of the 50 kDa HA macromer most resembled the properties of native cartilage and show the greatest promise for continued development for cartilage regeneration. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Restricted b‐factors in bipartite graphs and t‐designs
Authors: Arámbula Ivette , Hicks Illya V. 
Published: February 2006

AbstractWe present a new equivalence result between restricted b‐factors in bipartite graphs and combinatorial t‐designs. This result is useful in the construction of t‐designs by polyhedral methods. We propose a novel linear integer programming formulation, which we call GDP, for the problem of finding t‐designs that has a noteworthy advantage compared to the traditional set‐covering formulation. We analyze some polyhedral properties of GPD, implement a branch‐and‐cut algorithm using it and solve several instances of small designs to compare with another point‐block formulation found in the literature. © 2006 Wiley Periodicals, Inc. J Combin Designs 14: 169–182, 2006
Expression profiles of micro RNA in proliferating and differentiating 32D murine myeloid cells
Authors: Shi Bin , Prisco Marco , Calin George , Liu Chang‐gong , Russo Giuseppe , Giordano Antonio , Baserga Renato 
Published: February 2006

Abstract32D cells are murine myeloid cells that grow indefinitely in Interleukin‐3 (IL‐3). In these cells, the type 1 insulin‐like growth factor (IGF‐I) and granulocytic‐colony stimulating factor (G‐CSF) induce differentiation to granulocytes. 32D cells do not express insulin receptor substrate‐1 (IRS‐1) or IRS‐2, docking proteins of the IGF‐I receptor. Ectopic expression of IRS‐1 in these cells inhibits differentiation, the cells become IL‐3 independent and IGF‐1 dependent and can form tumors in mice. 32D and 32D‐derived cells offer a good model in which to study the expression profiles of Micro Rna (miR) related to sustained proliferation or differentiation. We present here the data obtained with miR micro‐arrays and identify the miR that are regulated by IGF‐1 or G‐CSF and are associated with either differentiation or indefinite cell proliferation of 32D murine myeloid cells. © 2006 Wiley‐Liss, Inc.
Characterizing medullary and human mesenchymal stem cell‐derived adipocytes
Authors: MacKay Danielle L. , Tesar Paul J. , Liang Li‐Nuo , Haynesworth Stephen E. 
Published: February 2006

AbstractThroughout postnatal years, medullary adipocytes (MAs) increase in both number and size; however, knowledge of these cells pales in comparison to that of other adipocyte depots. It is widely hypothesized that MAs derive from multipotent progenitor cells of the bone marrow, such as human mesenchymal stem cells (hMSCs). Nevertheless, there is a paucity of comparative, molecular‐level studies in support of this hypothesis. In the present article, RTPCR was used to examine similarities and differences in gene expression among MAs, hMSC‐derived adipocytes, and subcutaneous adipocytes. While little or no message for lineage‐specific markers was detected in undifferentiated hMSCs, the data demonstrate that hMSC‐derived adipocytes, MAs, and subcutaneous adipocytes commonly express mRNA encoding for adipogenic transcription factors (PPARγ2, C/EBPα, and SREBP1), adipokines (adipsin, leptin, APM1, and angiotensinogen), and lipid‐metabolizing agents (aP2 and LPL), among other genes. None of the cell populations examined expressed a detectable level of the brown fat marker UCP1. This suggests highly similar gene expression between human subcutaneous and MAs, not previously substantiated to this degree. Coupled with the hMSC‐derived adipocyte analysis, these data provide a framework ultimately for characterizing MAs and identifying their origin and function. J. Cell. Physiol. © 2006 Wiley‐Liss, Inc.
The Structural, Molecular and Functional Properties of Lignin‐Containing Beechwood Glucuronoxylan
Authors: Hromádková Zdenka , Ebringerová Anna , Malovíková Anna 
Published: February 2006

AbstractThe samples of 4‐O‐methyl‐D‐glucurono‐D‐xylan (GX) with different lignin and uronic acid (MeUA) contents were prepared from beechwood by various procedures. The re‐dissolution process of the partially water‐soluble GX‐2 lyophilizate in aqueous medium depended on the content and distribution of MeUA. In contrast to the supernatant after ultracentrifugation, the sediment had a significantly lower MeUA content and showed mainly high‐molecular mass components. A part of lignin degradation products is separable by repeated dissolution and precipitation of GX in acidic and alkaline 80% ethanolic media with assistance of ultrasound. Irradiation in acidic ethanol (GX‐3/ac) showed no effect on the distribution of the UV254‐absorbing component. GX‐3 sonicated in neutral and alkaline media (GX‐3/ne, GX‐3/alk) lost water solubility. The lignin‐rich GX samples showed remarkable emulsifying efficiency and protein foam stabilization effect. In addition, the presence of phenolics provided antioxidant properties to these xylan preparations indicating their potential as polymeric radical scavengers.
Cationic Xylan Derivatives with High Degree of Functionalization
Authors: Schwikal Katrin , Heinze Thomas , Ebringerová Anna , Petzold Katrin 
Published: February 2006

AbstractXylan from birch wood was characterized regarding both the supramolecular structure (X‐ray, CP/MAS 13C‐NMR) and the sugar composition. The reaction of the birch wood xylan with 2,3‐epoxypropyltrimethylammonium chloride in 1,2‐dimethoxyethane as slurry medium yields water‐soluble, cationic 2‐hydroxypropyltrimethylammonium xylan derivatives with high degree of substitution (DS). The DS values up to 1.6 can be controlled by adjusting the molar ratio in a one step synthesis. The structure of the cationic xylan derivatives was confirmed by means of DEPT(135) NMR spectroscopy. Film forming properties of cationic xylan derivatives were investigated with SEM measurements.
Synthesis of the Cellulose Model Compound Methyl 4″‐O‐Methyl‐β‐D‐Cellotrioside
Authors: del Carmen Ruiz Ruiz Maria , Querner Jens , Adorjan Immanuel , Kosma Paul , Rosenau Thomas 
Published: February 2006

AbstractA high‐yield synthetic route towards methyl 4″‐O‐methyl‐β‐D‐cellotrioside (17) via cellobioside acceptor 8 and glucosyl fluoride donor 15 was established. The former was synthesized from cellobiose peracetate in 7 steps and 21% overall yield, while the latter was obtained from methyl β‐D‐glucopyranoside in a 6‐step‐synthesis with 19% yield. Glycosidation afforded 13% of α‐compound besides the desired β‐isomer (31%). The target compound, being the higher homologue of the recently prepared 4′‐O‐methyl‐β‐D‐cellobioside (1), is required to study by solid‐state techniques the hydrogen bond network in cellodextrins and cellulose, and its changes upon swelling and dissolution.
Comparison of Aqueous and Non‐Aqueous Treatments of Cellulose to Reduce Copper‐Catalyzed Oxidation Processes
Authors: Henniges Ute , Banik Gerhard , Potthast Antje 
Published: February 2006

AbstractSummary. The present paper examines oxidative degradation of cellulose catalyzed by presence of Cu1+and Cu2+ ions in the context of historic paper conservation treatments. Aqueous treatments of degraded papers further spread transition metal ions, such as copper, across the fibre matrix, and therefore augment the detrimental effect of these ions. In the paper industry, the inhibiting effects of magnesium ions on metal‐catalyzed degradation of cellulose contaminated with metal impurities have been observed. Also, magnesium compounds dissolved in alcoholic or aqueous solutions are generally used in paper conservation as deacidification agents. Paper samples with artificially produced copper corrosion served as mock‐ups for examination and comparison of different treatments which focused on the inhibiting effect of magnesium and antioxidants. Analytical examination of molecular weight distribution, carbonyl content, carboxyl content, and surface pH was performed. Results show an inhibiting effect of magnesium on copper‐catalyzed cellulose degradation, although less pronounced than expected.
Comparing Dichromate Oxidation and Size Exclusion Chromatography of Dissolved Carbohydrates
Authors: Schmidt Ingeborg , Fischer Klaus , Weightman Derek 
Published: February 2006

AbstractStandardised methods are used to characterise the pulp or cellulosic material for its alkali resistance and alkali solubility. Today, pulp is usually characterised by its solubility in sodium hydroxide. The characterisation test was based on the treatment of pulp with sodium hydroxide solution of a defined concentration, according to a specified procedure. The dissolved organic matter was then determined by dichromate oxidation. The results obtained by size exclusion chromatography showed that both the amount and the molecular weight of the dissolved carbohydrates vary when investigating solubility and α‐cellulose content of pulps. The results show further that S18 values obtained by dichromate oxidation are overestimated when characterising pulps containing higher amounts of hemicellulose and/ or short chain cellulose, compared with results obtained by the SEC method. On the contrary, S10 values are overestimated when determined by dichromate oxidation in higher alpha pulps.
Expression of heregulin by mouse mammary tumor cells: Role in activation of ErbB receptors
Authors: Schmitt M. , Walker M.P. , Richards R.G. , Bocchinfuso W.P. , Fukuda T. , Medina D. , Kittrell F.S. , Korach K.S. , DiAugustine R.P. 
Published: February 2006

AbstractThe inappropriate activation of one or more members of the ErbB family of receptor tyrosine kinases [ErbB‐1 (EGFR), ErbB‐2, ErbB‐3, ErbB‐4] has been linked with oncogenesis. ErbB‐2 is frequently coexpressed with ErbB‐3 in breast cancer cells and in the presence of the ligand heregulin (HRG) the ErbB‐2/ErbB‐3 receptors form a signaling heterodimer that can affect cell proliferation and apoptosis. The major goal of the present study was to determine whether endogenous HRG causes autocrine/paracrine activation of ErbB‐2/ErbB‐3 and contributes to the proliferation of mammary epithelial tumor cells. Tyrosine‐phosphorylated (activated) ErbB‐2 and ErbB‐3 receptors were detected in the majority of extracts from tumors that had formed spontaneously or as a result of oncogene expression. HRG‐1 transcripts and protein were found in the epithelial cells of most of these mouse mammary tumors. Various mouse mammary cell lines also contained activated ErbB‐2/ErbB‐3 and HRG transcripts. A ∼50 kDa C‐terminal fragment of pro‐HRG was detected, which indicates that the HRG‐1 precursor is readily processed by these cells. It is likely that the secreted mature HRG activated the ErbB‐2/3 receptors. Addition of an antiserum against HRG to the mammary epithelial tumor cell line TM‐6 reduced ErbB‐3 Tyr‐phosphorylation. Treatment with HRG‐1 siRNA oligonucleotides or infection with a retroviral construct to stably express HRG siRNA effectively reduced HRG protein levels, ErbB‐2/ErbB‐3 activation, and the rate of proliferation, which could be reversed by the addition of HRG. The cumulative findings from these experiments show that coexpression of the HRG ligand contributes to activation of ErbB‐2/Erb‐3 in mouse mammary tumor cells in an autocrine or paracrine fashion. Published 2006 Wiley‐Liss, Inc.