bluuebunny/crossref_metadata_2025_split huggingface dataset:
Free‐solution electrophoretic separations of DNA–drag‐tag conjugates on glass microchips with no polymer network and no loss of resolution at increased electric field strength
Authors: Albrecht Jennifer Coyne , Kerby Matthew B. , Niedringhaus Thomas P. , Lin Jennifer S. , Wang Xiaoxiao , Barron Annelise E. 
Published: April 2011

AbstractHere, we demonstrate the potential for high‐resolution electrophoretic separations of ssDNA–protein conjugates in borosilicate glass microfluidic chips, with no sieving media and excellent repeatability. Using polynucleotides of two different lengths conjugated to moderately cationic protein polymer drag‐tags, we measured separation efficiency as a function of applied electric field. In excellent agreement with prior theoretical predictions of Slater et al., resolution is found to remain constant as applied field is increased up to 700 V/cm, the highest field we were able to apply. This remarkable result illustrates the fundamentally different physical limitations of free‐solution conjugate electrophoresis (FSCE)‐based DNA separations relative to matrix‐based DNA electrophoresis. ssDNA separations in “gels” have always shown rapidly declining resolution as the field strength is increased; this is especially true for ssDNA > 400 bases in length. FSCE's ability to decouple DNA peak resolution from applied electric field suggests the future possibility of ultra‐rapid FSCE sequencing on chips. We investigated sources of peak broadening for FSCE separations on borosilicate glass microchips, using six different protein polymer drag‐tags. For drag‐tags with four or more positive charges, electrostatic and adsorptive interactions with poly(N‐hydroxyethylacrylamide)‐coated microchannel walls led to appreciable band‐broadening, while much sharper peaks were seen for bioconjugates with nearly charge‐neutral protein drag‐tags.
Electrokinetic supercharging with a system‐induced terminator and an optimized capillary versus electrode configuration for parts‐per‐trillion detection of rare‐earth elements in CZE
Authors: Xu Zhongqi , Kawahito Kouji , Ye Xiaoxue , Timerbaev Andrei R. , Hirokawa Takeshi 
Published: April 2011

AbstractA further improvement of electrokinetic supercharging (EKS) methodology has been proposed, with the objective to enhance the sensitivity of the conventional CZE‐UV method down to a single‐digit part per trillion (ppt) level. The advanced EKS procedure is based on a novel phenomenon displaying the formation of a zone with an increased concentration of the hydrogen ion, capable to perform the function of a terminator, behind the sample zone upon electrokinetic injection. In combination with a visualizing co‐ion of BGE, protonated 4‐methylbenzylamine, acting as the leading ion, such system‐induced terminator a effected the transient ITP state to efficiently concentrate cationic analytes prior to CZE. Furthermore, to amass more analyte ions within the effective electric field at the injection stage, a standard sample vial was replaced with an elongated vial that allowed the sample volume to be increased from 500 to 900 μL. Alongside, this replacement made the upright distance between the electrode and the capillary tips prolonged to 40.0 mm to achieve high‐efficiency electrokinetic injection. The computer simulation was used for profiling analyte concentration, pH, and field strength in order to delineate formation of the terminator during sample injection. The proposed preconcentration strategy afforded an enrichment factor of 80 000 and thereby the LODs of rare‐earth metal ions at the ppt level, e.g. 0.04 nM (6.7 ng/L) for erbium(III).
Optimization of separation of heavy metals by capillary electrophoresis with contactless conductivity detection
Authors: Lau Hiu Fung , Quek Ngee Mian , Law Wai Siang , Zhao Jian Hong , Hauser Peter C. , Li Sam Fong Yau 
Published: April 2011

AbstractThe separation of four toxic metal ions (Cr3+, Pb2+, Hg2+, Ni2+) was achieved by optimizing the composition of the histidine/tartaric acid background electrolyte. An on‐column preconcentration technique, viz. field amplified sample injection, was performed to improve the sensitivity. This method afforded an enhancement factor of up to 91 800 fold with the LODs ranging from 0.005 to 2.32 μg/L, which were well below the maximum contaminant levels set by the United States Environmental Protection Agency. The robustness of this method was demonstrated with its application to the analysis of real samples including tap water, drain water, and reservoir water with recoveries between 90 and 120%.
Rapid and simple pretreatment of human body fluids using electromembrane extraction across supported liquid membrane for capillary electrophoretic determination of lithium
Authors: Strieglerová Lenka , Kubáň Pavel , Boček Petr 
Published: April 2011

AbstractElectromembrane extraction was used for simultaneous sample cleanup and preconcentration of lithium from untreated human body fluids. The sample of a body fluid was diluted 100 times with 0.5 mM Tris solution and lithium was extracted by electromigration through a supported liquid membrane composed of 1‐octanol into 100 mM acetic acid acceptor solution. Matrix compounds, such as proteins, red blood cells, and other high‐molecular‐weight compounds were efficiently retained on the supported liquid membrane. The liquid membrane was anchored in pores of a short segment of a polypropylene hollow fiber, which represented a low cost, single use, disposable extraction unit and was discarded after each use. Acceptor solutions were analyzed using capillary electrophoresis with capacitively coupled contactless conductivity detection (CE‐C4D) and baseline separation of lithium was achieved in a background electrolyte solution consisting of 18 mM L‐histidine and 40 mM acetic acid at pH 4.6. Repeatability of the electromembrane extraction‐CE‐C4D method was evaluated for the determination of lithium in standard solutions and real samples and was better than 0.6 and 8.2% for migration times and peak areas, respectively. The concentration limit of detection of 9 nM was achieved. The developed method was applied to the determination of lithium in urine, blood serum, blood plasma, and whole blood at both endogenous and therapeutic concentration levels.
Nanoparticle‐based pseudostationary phases in CEC: A breakthrough in protein analysis?
Authors: Nilsson Christian , Birnbaum Staffan , Nilsson Staffan 
Published: April 2011

AbstractThis review focuses on major trends in nanoparticle‐based pseudostationary phase (PSP) CEC since the publication of our previous reviews within nanoparticle‐based CEC [Nilsson, C., et al., Electrophoresis 2006, 27, 76‐83; Nilsson, C., et al., J. Chromatogr. A 2007, 1168, 212‐224.]. Special attention is given to the development toward protein analysis, which is driven by the strong emergence of protein drug development in the pharmaceutical industry. Furthermore, we discuss the development in coupling different detection techniques with nanoparticle‐based PSP CEC, which were originally predicted to be particularly cumbersome. However, at present, direct UV, LIF and ESI‐MS have been used without any severe complications. Different types of nanoparticles used as PSP during the period include gold nanoparticles, carbon nanostructures and lipid‐based nanoparticles. New materials (for example, different types of carbon nanostructures and self assembled lipid‐based nanostructures) are a strong driving force for development in separation science. Finally, future trends in nanoparticles‐based CEC are envisioned.
Capillary electrophoresis immunoassays with conjugated quantum dots
Authors: Klepárník Karel , Voráčová Ivona , Lišková Marcela , Přikryl Jan , Hezinová Věra , Foret František 
Published: April 2011

AbstractWater‐soluble CdTe quantum dots (QDs) and their conjugates with antibodies and antigenes were prepared by optimized procedures for applications in CE immunoassays. The QD size of 3.5 nm, excitation spectrum in the range of 300–500 nm, the maximum wavelength of the emission spectrum at 610 nm, quantum yield of 0.25 and luminescence lifetimes in the range of 3.6–43 ns were determined. The 0.1 M solution of TRIS/TAPS (pH 8.3) was found to be the optimum buffer for the separation of the antiovalbumin–ovalbumin immunocomplex from the free conjugates of QDs.
Determination of acrylamide in potato crisps by capillary electrophoresis with quantum dot‐mediated LIF detection
Authors: Chen Qidan , Zhao Wenfeng , Fung Yingsing 
Published: April 2011

AbstractAcrylamide or 2‐propenamide (AAM), a water‐soluble toxic contaminant, has recently caused health concern after it was found in food products made by high‐temperature cooking. Due to its weak UV absorption and electrochemically inactive state, common analytical methods do not have sufficient sensitivity to meet the World Health Organization requirement. A LIF detection method mediated by water‐soluble CdTe quantum dots capped with mercaptopropyl acid (MPA) is thus developed for AAM quantitation. The optimized conditions are as follows: 30 mmol/L SDS, 0.1 mmol/L quantum dot, and 40 mmol/L phosphate buffer solution at pH 8.0 under 18 kV run voltage with LIF detection at 473 nm excitation and 568 nm fluorescence. The linear quantitation range for AAM was found to vary from 1.0 to 100 mg/kg and a detection limit (S/N=2) at 0.1 mg/kg, showing sufficient sensitivity to meet the maximum AAM specified by the Joint Food and Agriculture Organization/World Health Organization Expert Committee for potato crisps. Recoveries for potato crisps sample spiked with 10, 20, and 100 mg/kg AAM were found to vary between 90 and 95% with RSD <5.7% (n=3).
Molecular modelling and models in the study of sweet and umami taste receptors. A review.
Authors: Morini Gabriella , Bassoli Angela , Borgonovo Gigliola 
Published: April 2011

ABSTRACTThe mechanism of action of tastants has been under investigation for many years. For the sweet taste several models have been developed to describe the nature and topological arrangement of the glucophores of ideal sweet compounds and/or the recognition sites of the sweet taste receptor. In less than a decade our knowledge about the mechanism of sweet taste chemoreception has grown enormously, following the identification and cloning of T1Rs. The observation that receptor cells co‐expressing T1R2 and T1R3 respond to a great variety of sweet compounds has been generally interpreted as an inference that there is a single heterodimeric receptor for sweet taste. The three‐dimensional structure of the receptor is not known and alternative methodologies are required to model the binding of sweet compounds. Therefore homology modelling and molecular modelling become indispensable tools to suggest point mutations which further define the binding regions. Only their cooperative effect allowed researchers to determine several molecular mechanisms of the sweet taste receptors, including the modality of action of blockers and positive allosteric modulators. For umami taste, despite the general appreciation of the meaty, mouth filling and rich taste found in many foods (and the great interest of the food industry thereof), the existence of an umami receptor has been accepted only after its cloning. Probably because of this, no umami taste receptor models have been developed, while the molecular mechanism for its synergism has been unravelled before that of the sweet taste receptor. Copyright © 2011 John Wiley & Sons, Ltd.
Parental income and child health in Germany
Authors: Reinhold Steffen , Jürges Hendrik 
Published: April 2011

SUMMARYUsing newly available data from Germany, we study the relationship between parental income and child health. We find a strong gradient between parental income and subjective child health as has been documented earlier in the United States, Canada, and the United Kingdom. The relationship in Germany is about as strong as in the United States and stronger than in the United Kingdom. However, in contrast to US results, we do not find consistent evidence that the disadvantages associated with low parental income accumulate as the child ages, nor that children from low socioeconomic background are more likely to suffer from doctor‐diagnosed conditions. There is some evidence, however, that high‐income children are better able to cope with the adverse consequences of chronic conditions. Investigating potential diagnosis bias, we find only weak evidence for health disadvantages for low‐income children when using objective health measures, but some evidence for under‐utilization of health services among low‐income families. Copyright © 2011 John Wiley & Sons, Ltd.
How strong is the case for dollarization in Central America? An empirical analysis of business cycles, credit market imperfections and the exchange rate
Authors: Lindenberg Nannette , Westermann Frank 
Published: April 2011

ABSTRACTIn this paper, we contrast two different views in the debate on official dollarization. The Mundell framework of optimum currency areas and a model on boom–bust cycles, by Schneider and Tornell, who take account of credit market imperfections prevalent in middle income countries. We highlight that the role of the exchange rate is strikingly different in the two models. Although in the Mundell framework, the exchange rate is expected to smooth the business cycle, the other model predicts that the exchange rate plays an amplifying role. We empirically evaluate both models for eight highly dollarized Central American economies. We document the existence of credit market imperfections and find that shocks from the exchange rate indeed amplify business cycles in these countries. Using a new method of Cubadda, we furthermore test for cyclical comovement and reject the hypothesis that the countries form an optimum currency area with the United States according to the Mundell definition. Copyright © 2011 John Wiley & Sons, Ltd.
Mechanical and acid neutralizing properties and bacteria inhibition of amorphous calcium phosphate dental nanocomposite
Authors: Moreau Jennifer L. , Sun Limin , Chow Laurence C. , Xu Hockin H. K. 
Published: April 2011

AbstractDental composites do not hinder bacteria colonization and plaque formation. Caries at the restoration margins is a frequent reason for replacement of existing restorations, which accounts for 50 to 70% of all restorations. The objectives of this study were to examine the filler level effect on nanocomposite containing nanoparticles of amorphous calcium phosphate (NACP) and investigate the load‐bearing and acid‐neutralizing properties and bacteria inhibition. NACP with 116‐nm particle size were synthesized via a spray‐drying technique and incorporated into a resin. Flexural strength of nanocomposite with 10 to 30% NACP fillers matched the strength of a commercial hybrid composite (p > 0.1). Nanocomposite with 40% NACP matched the strength of a microfill composite, which was 2‐fold that of a resin‐modified glass ionomer. Nanocomposite with 40% NACP neutralized a lactic acid solution of pH 4 by rapidly increasing the pH to 5.69 in 10 min. In contrast, the commercial controls had pH staying at near 4. Using Streptoccocus mutans, an agar disk‐diffusion test showed no inhibition zone for commercial controls. In contrast, the inhibition zone was (2.5 ± 0.7) mm for nanocomposite with 40% NACP. Crystal violet staining showed that S. mutans coverage on nanocomposite was 1/4 that on commercial composite. In conclusion, novel calcium–phosphate nanocomposite matched the mechanical properties of commercial composite and rapidly neutralized lactic acid of pH 4. The nanocomposite appeared to moderately reduce the S. mutans growth, and further study is needed to obtain strong antimicrobial properties. The new nanocomposite may have potential to reduce secondary caries and restoration fracture, two main challenges facing tooth cavity restorations. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Viscoelastic properties of injectable bone cements for orthopaedic applications: State‐of‐the‐art review
Authors: Lewis Gladius 
Published: April 2011

AbstractInjectable bone cements (IBCs) are used for a variety of orthopaedic applications, examples being poly (methyl methacrylate) (PMMA) bone cements used for anchoring total joint replacements (TJRs) (high load‐bearing application), PMMA bone cements used in the vertebral body augmentation procedures of vertebroplasty (VP) and balloon kyphoplasty (BKP) (medium load‐bearing application), and calcium phosphate‐based and calcium sulfate‐based cements used as bone void fillers/bone graft substitutes (low load‐bearing application). For each of these applications, the viscoelastic properties of the cement are very important. For example, (1) creep of the cement has an influence on the longevity of a cemented TJR (for example, creep allows the cement to remodel, thereby maximizing the contact area of the cement‐bone interface and, hence, minimizing stress concentration at that interface); and (2) in VP and BKP, the likelihood of cement extravasation is directly related to the profile of the viscosity‐versus‐time elapsed from commencement of mixing of the cement. There are a few reviews of the literature on a number of viscoelastic properties of some IBCs but a comprehensive review of the literature on all viscoelastic properties of all IBCs is lacking. The objective of this contribution is to present such a review. In addition, a number of ideas for future study in the field of viscoelastic properties of IBCs are described. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
SHIP2 multiple functions: A balance between a negative control of PtdIns(3,4,5)P3 level, a positive control of PtdIns(3,4)P2 production, and intrinsic docking properties
Authors: Erneux Christophe , Edimo William's Elong , Deneubourg Laurence , Pirson Isabelle 
Published: April 2011

AbstractThe SH2 domain containing inositol 5‐phosphatase 2 (SHIP2) belongs to the family of the mammalian inositol polyphosphate 5‐phosphatases. The two closely related isoenzymes SHIP1 (or SHIP) and SHIP2 contain a N‐terminal SH2 domain, a catalytic domain, potential PTB domain‐binding sites (NPXY), and C‐terminal proline‐rich regions with consensus sites for SH3 domain interactions. In addition, SHIP2 contains a unique sterile alpha motif (SAM) domain that could be involved in SAM–SAM domain interactions with other proteins or receptors. SHIP2 also shows the presence of an ubiquitin interacting motif at the C‐terminal end. SHIP2 is essentially a PI(3,4,5)P3 5‐phosphatase that negatively controls PI(3,4,5)P3 levels in intact cells and produce PI(3,4)P2. Depending on the cells and stimuli, PI(3,4)P2 could accumulate at important levels and be a “second messenger” by its own. It could interact with a very large number of target proteins such as PKB or TAPP1 and 2 that control insulin sensitivity. In addition to its catalytic activity, SHIP2 is also a docking protein for a large number of proteins: Cytoskeletal, focal adhesion proteins, scaffold proteins, adaptors, protein phosphatases, and tyrosine kinase associated receptors. These interactions could play a role in the control of cell adhesion, migration, or endocytosis of some receptors. SHIP2 could be acting independently of its phosphatase activity being part of a protein network of some receptors, e.g., the EGF receptor or BCR/ABL. These non‐catalytic properties associated to a PI phosphatase have also been reported for other enzymes of the metabolism of myo‐inositol such as Ins(1,4,5)P3 3‐kinases, inositol phosphate multikinase (IPMK), or PTEN. J. Cell. Biochem. 112: 2203–2209, 2011. © 2011 Wiley‐Liss, Inc.
Comprehensive patterns in microRNA regulation of transcription factors during tumor metastasis
Authors: Reshmi G. , Sona Charles , Pillai M. Radhakrishna 
Published: April 2011

AbstractIn spite of a large body of information about the upstream regulators of metastasis, a process that often plays a limiting factor in therapeutic outcome of cancer patients, the impact of regulatory microRNA patterns remains obscure. This review describes computational analysis of coordinated regulation of genes by di‐directional regulation of microRNA and transcription factors that specifically regulate the process of metastasis. We discovered several unexpected modes of regulatory patterns between microRNAs and transcription factors. For example, we found a double positive feedback loop regulated by the hub transcription factor ZEB1 and miR‐200 during epithelial–mesenchymal transition. This review further explains flow of information and how such components coordinate various adaptable controls of microRNAs and thus, contribute to regulation of transcription factors in context of cancer metastasis. Information described here provides a regulatory framework for future experimental analyses and discoveries of new insights into post‐transcriptional gene regulation at the microRNA level in cancer metastasis. J. Cell. Biochem. 112: 2210–2217, 2011. © 2011 Wiley‐Liss, Inc.
Over‐expression of FoxM1 leads to epithelial–mesenchymal transition and cancer stem cell phenotype in pancreatic cancer cells
Authors: Bao Bin , Wang Zhiwei , Ali Shadan , Kong Dejuan , Banerjee Sanjeev , Ahmad Aamir , Li Yiwei , Azmi Asfar S. , Miele Lucio , Sarkar Fazlul H. 
Published: April 2011

AbstractFoxM1 is known to play important role in the development and progression of many malignancies including pancreatic cancer. Studies have shown that the acquisition of epithelial‐to‐mesenchymal transition (EMT) phenotype and induction of cancer stem cell (CSC) or cancer stem‐like cell phenotypes are highly inter‐related, and contributes to drug resistance, tumor recurrence, and metastasis. The molecular mechanism(s) by which FoxM1 contributes to the acquisition of EMT phenotype and induction of CSC self‐renewal capacity is poorly understood. Therefore, we established FoxM1 over‐expressing pancreatic cancer (AsPC‐1) cells, which showed increased cell growth, clonogenicity, and cell migration. Moreover, over‐expression of FoxM1 led to the acquisition of EMT phenotype by activation of mesenchymal cell markers, ZEB1, ZEB2, Snail2, E‐cadherin, and vimentin, which is consistent with increased sphere‐forming (pancreatospheres) capacity and expression of CSC surface markers (CD44 and EpCAM). We also found that over‐expression of FoxM1 led to decreased expression of miRNAs (let‐7a, let‐7b, let‐7c, miR‐200b, and miR‐200c); however, re‐expression of miR‐200b inhibited the expression of ZEB1, ZEB2, vimentin as well as FoxM1, and induced the expression of E‐cadherin, leading to the reversal of EMT phenotype. Finally, we found that genistein, a natural chemo‐preventive agent, inhibited cell growth, clonogenicity, cell migration and invasion, EMT phenotype, and formation of pancreatospheres consistent with reduced expression of CD44 and EpCAM. These results suggest, for the first time, that FoxM1 over‐expression is responsible for the acquisition of EMT and CSC phenotype, which is in part mediated through the regulation of miR‐200b and these processes, could be easily attenuated by genistein. J. Cell. Biochem. 112: 2296–2306, 2011. © 2011 Wiley‐Liss, Inc.