bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functionalized Cyclodextrins as First and Second Coordination Sphere Ligands for Aqueous Organometallic Catalysis
Authors: Hapiot Frédéric , Bricout Hervé , Tilloy Sébastien , Monflier Eric 
Published: February 2012

AbstractSupramolecular catalysis now forms a viable and challenging interdisciplinary topic that drives chemists to design new ligands and their metal complexes. Functionalized cyclodextrins (CDs) have attracted particular attention in this respect because of their molecular recognition and metal coordination ability. They can act both as first‐coordination‐sphere ligands through coordination of a phosphanyl or amino group onto the metal and as second‐coordination‐sphere ligands because of the inclusion of a guest molecule (substrate or ligand) inside their cavity. These combined features make functionalized CDs very special objects. The present review seeks to address the scope of these supramolecular entities as ligands for the elaboration of novel organometallic complexes for aqueous catalysis.
Transition‐Metal‐Mediated Cleavage and Activation of C–C Single Bonds
Authors: Ruhland Klaus 
Published: February 2012

AbstractThe activation and cleavage of C–C single bonds mediated by transition metal complexes is one of the most challenging reactions, both practically and in terms of understanding, in the field of metal organic chemistry. In this review the fundamental reactions – oxidative addition, β‐carbon elimination, retro‐allylation, and radical cleavage – so far successfully applied for this transformation are discussed in terms of their mechanisms, their intrinsic problems, and their published examples, which are still fairly rare. Decarbonylation, as another fundamental reaction, is only touched briefly. This group of reactions is today poised to set aside its shadow existence as an exotic reaction class. Meanwhile the number of catalytic and even enantioselective processes involvingC–C single bond cleavage is slowly increasing, although the substrates used in these reactions are still limited to quite special connection patterns. The basic challenges for the future and the paradigms concerning this reaction are presented.
Enhancement of Enzymatic IDE Biosensor Response Using Gold Nanoparticles. Example of the Detection of Urea
Authors: Nouira W. , Maaref A. , Vocanson F. , Siadat M. , Saulnier J. , Lagarde F. , Jaffrezic‐Renault N. 
Published: February 2012

AbstractA new conductometric biosensor based on interdigitated electrodes (IDEs) has been developed for the detection of enzymatic substrates using gold nanoparticles (GNPs), synthesized bellowing the citrate process, with an average diameter of 23 nm and functionalized with urease using layer‐by‐layer technique. A detection limit of 100 µM of urea is obtained when cross‐linked urease is directly immobilized on top of the IDEs (interdigitated distance: 20 µm) whereas a detection limit of 2 µM is obtained when urease functionalized gold nanoparticles are deposited on the top of the IDEs. The use of gold nanoparticles allows the increase of the sensitivity of detection (from 10 µS/mM to 107 µS/mM) due to the decrease of the thickness of probed zone.
Permeability of Human Tooth Surfaces Studied In Vitro by Electrochemical Impedance Spectroscopy
Authors: Pita Marcos , Halámek Jan , Chinnapareddy Soujanya , White Donald J. , Gartstein Vladimir , Katz Evgeny 
Published: February 2012

AbstractElectrochemical Faradaic impedance spectroscopy was applied to evaluate dependence of the electrical resistance on human teeth. The experiments were performed using iodide anions as a redox probe to model permeability of teeth for fluoride upon an iontophoresis process. Tooth molars were used – as these are teeth most affected by tooth decay processes in vivo. Teeth compared included sound molars – with no evidence of pit and fissure decay, teeth with pits and fissures regarded ‘clinically’ as showing signs of decay, and teeth with crowns removed to present exposed dentin surfaces. A difference of more than an order of magnitude in electrical resistance was observed between sound molars and those regarded as showing evidence of tooth decay processes. Sound dentin, as expected from structural considerations demonstrated significantly lower resistance when compared to sound molars. Importantly, the difference in tooth resistance measured between carious and sound molars was shown to be much more representative of their structural integrity than comparison of digitally processed images of the teeth. The results support the utility of electrochemical Faradaic impedance spectroscopy for the development of understanding on how tooth electrical resistance may vary according to structural changes. This understanding may be useful to continued refinements in the use of electrical resistance measures as caries diagnostics and support generically the potential for iontophoretic processes in in‐office fluoride treatments of teeth.
Dietary- and tissue-based exposure of belted kingfisher to PCDFs and PCDDs in the Tittabawassee River floodplain, Midland, MI, USA
Authors: Seston Rita M. , Giesy John P. , Fredricks Timothy B. , Tazelaar Dustin L. , Coefield Sarah J. , Bradley Patrick W. , Roark Shaun A. , Newsted John L. , Kay Denise P. , Zwiernik Matthew J. 
Published: February 2012

Abstract
Concentrations of polychlorinated dibenzofurans (PCDFs) and other dioxin-like compounds in soils and sediments of the Tittabawassee River and associated floodplains downstream of Midland, Michigan, USA, are greater than upstream sites. As a result of these concentrations, which are some of the greatest ever reported, a site-specific exposure assessment of belted kingfisher breeding in the assessment area was conducted. To reduce the uncertainty associated with predicting exposure from abiotic matrices, concentrations of residues were quantified in site-specific prey items and in eggs and nestlings of belted kingfisher. Dietary exposure, expressed as the potential average daily dose, based on site-specific concentrations of PCDFs, polychlorinated dibenzo-p-dioxins (PCDDs), and 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQWHO-Avian) in prey items was consistently greater along the Tittabawassee River than in associated reference areas and further downstream sites in the Saginaw River. Concentrations of PCDD/DFs in eggs and nestlings of belted kingfisher varied among sampling areas, being greater in both eggs and nestlings nesting along the Tittabawassee River compared to those of belted kingfisher from upstream reference areas. Geometric mean concentrations of PCDD/DFs were 130 and 200 ng/kg wet weight in eggs and nestlings of belted kingfisher, respectively. These concentrations are the equivalent of 84 and 95 ng TEQWHO-Avian/kg. Site-specific biomagnification factors for select PCDD/DF congeners ranged from &lt;1.0 to 1.8 in belted kingfisher. Environ. Toxicol. Chem. 2012; 31: 1158–1168. © 2012 SETAC
Review of toxicological effects caused by episodic stressor exposure
Authors: Gordon Andrew K. , Mantel Sukhmani K. , Muller Nikite W.J. 
Published: February 2012

Abstract
Water quality monitoring tools that rely on data from stress-response tests with continuous exposure at constant concentrations are not always appropriately protective when stressor exposure in the field is episodic in nature. The present study identifies various approaches that have attempted to account for episodic stressor exposure, describes the development of a toxicological effects database of episodic stressor exposure collated from published scientific literature, and discusses whether any discernible trends are evident when these data are reviewed. The episodic stressor exposure literature indicated that few generalizations can be made regarding associated biological responses. Instead, when attempting to characterize the hazard of a certain episodic pollution event, the following situation-specific information is required: the specific species affected and its age, the specific stressor and its concentration, the number of exposures to the stressor, the duration of exposure to the stressor, and the recovery time after each exposure. The present study identifies four main challenges to the inclusion of episodic toxicity data in environmental water quality management: varying stressor concentration profiles, defining episodic stressor concentration levels, variation resulting from routes of exposure and modes of action, and species-specific responses to episodic stressor exposure. The database, available at http://iwr.ru.ac.za/iwr/download, could be particularly useful for site-specific risk assessments related to episodic exposures. Environ. Toxicol. Chem. 2012; 31: 1169–1174. © 2012 SETAC
Natural colloids are the dominant factor in the sedimentation of nanoparticles
Authors: Quik Joris T.K. , Stuart Martien Cohen , Wouterse Marja , Peijnenburg Willie , Hendriks A. Jan , van de Meent Dik 
Published: February 2012

Abstract
Estimating the environmental exposure to manufactured nanomaterials is part of risk assessment. Because nanoparticles aggregate with each other (homoaggregation) and with other particles (heteroaggregation), the main route of the removal of most nanoparticles from water is aggregation, followed by sedimentation. The authors used water samples from two rivers in Europe, the Rhine and the Meuse. To distinguish between small (mainly natural organic matter [NOM]) particles and the remainder of the natural colloids present, both filtered and unfiltered river water was used to prepare the particle suspensions. The results show that the removal of nanoparticles from natural river water follows first-order kinetics toward a residual concentration. This was measured in river water with less than 1 mg L−1 CeO2 nanoparticles. The authors inferred that the heteroaggregation with or deposition onto the solid fraction of natural colloids was the main mechanism causing sedimentation in relation to homoaggregation. In contrast, the NOM fraction in filtered river water stabilized the residual nanoparticles against further sedimentation for up to 12 d. In 10 mg L−1 and 100 mg L−1 CeO2 nanoparticle suspensions, homoaggregation is likely the main mechanism leading to sedimentation. The proposed model could form the basis for improved exposure assessment for nanomaterials. Environ. Toxicol. Chem. 2012; 31: 1019–1022. © 2012 SETAC
Prognostic role of methylated free circulating DNA in colorectal cancer
Authors: Philipp Alexander B. , Stieber Petra , Nagel Dorothea , Neumann Jens , Spelsberg Fritz , Jung Andreas , Lamerz Rolf , Herbst Andreas , Kolligs Frank T. 
Published: February 2012

AbstractDNA hypermethylation is frequently found in colorectal cancer (CRC). Methylation of helicase‐like transcription factor (HLTF) and hyperplastic polyposis 1 (HPP1) are potential and carcinoembryonic antigen (CEA) is an established prognostic factor in serum of patients with CRC. The aim of this study was to perform a direct comparison of the prognostic roles of these markers. Methylation status of HLTF and HPP1 was examined in pretherapeutic sera of 311 patients with CRC and matched primary tissues of 54 stage IV patients using methylation‐specific quantitative PCR. CEA was determined using an immunoenzymometric assay. Methylation of HLTF and HPP1 DNA in serum significantly correlated with tumor size, stage, grade and metastatic disease. HPP1 methylation correlated with nodal status. Overall survival was shortened in case of methylation of HLTF or HPP1 or elevated levels of CEA (p < 0.0001 for all). In stage IV, patients survival was impaired if HLTF (p = 0.0005) or HPP1 (p = 0.0003) were methylated or CEA was above the median of 27 ng/ml (p = 0.002). Multivariate analysis revealed that methylation of HLTF [hazard ratio (HR) 1.8, p = 0.0438], HPP1 (HR 1.6, p = 0.0495) and CEA >27 ng/ml (HR 1.7, p = 0.0317) were independent prognostic factors in stage IV. The combination of any two or all three of these factors outperformed each marker on its own. In conclusion, the presence of methylated DNA of the genes HLTF or HPP1 in serum are independent prognostic factors in metastasized CRC. Prospective validation is required to determine their usefulness in clinical routine along with the established marker CEA.
Tumor‐promoting macrophages induce the expression of the macrophage‐specific receptor CD163 in malignant cells
Authors: Maniecki Maciej Bogdan , Etzerodt Anders , Ulhøi Benedicte Parm , Steiniche Torben , Borre Michael , Dyrskjøt Lars , Ørntoft Torben Falck , Moestrup Søren Kragh , Møller Holger Jon 
Published: February 2012

AbstractTumor‐associated macrophages (TAMs) represent a distinct malignancy‐promoting phenotype suggested to play a key role in tumor formation and metastasis. We aimed to investigate the expression of the monocyte/macrophage‐restricted receptor CD163 in bladder tumor biopsies and assess the potential mechanism inducing the CD163 expression in tumor cells. A high CD163 mRNA expression (n = 87) was significantly associated with a poor 13‐year overall survival (log‐rank test, χ2 = 8.931; p = 0.0028). Moreover, CD163 mRNA expression was significantly increased in muscle invasive (T2–T4), p = 0.017, and aggressive (grade III/IV) cancers (p = 0.015). The expression strongly correlated with local expression of IL‐6 (r = 0.72; p <0.0001) and IL‐10 (r = 0.75; p <0.0001), mediators known to induce CD163 expression in vitro. CD163 immunostaining (n = 46) confirmed the association between dense TAM infiltration and histologically advanced disease. In 39% of the biopsies, CD163 immunoreactivity was also observed in tumor cells, and CD163‐expressing metastatic cells were identified in lymph node biopsies (n = 8). Bladder cancer cell lines did not express CD163; however, when cocultured with macrophages the bladder cancer cell expression of CD163 was significantly induced in an IL‐6/IL‐10 independent manner. In conclusion, we show a strong association between CD163 mRNA expression in bladder cancer biopsies and poor patient outcome. CD163 expression was not confined to the infiltrating TAMs, but was also expressed by a significant portion of the malignant cells in both tumors and lymph nodes. CD163 expressing tumor cells may constitute a subpopulation of tumor cells with a phenotypic shift associated with epithelial‐to‐mesenchymal transition (EMT) and increased metastatic activity induced by TAMs.
USING NEURAL NETS TO COMBINE INFORMATION SETS IN CORPORATE BANKRUPTCY PREDICTION
Authors: Peat Maurice , Jones Stewart 
Published: February 2012

SUMMARYWe demonstrate that the use of a neural network (NN) model to combine information from corporate financial statements and equity markets provides improved predictive estimates of the probability of corporate bankruptcy. Using performance measures, based on the receiver operating characteristic curve, the forecast combinations from the NN models are demonstrated to outperform the forecasts derived from a forecast combination generated using a logistic regression approach. This result provides support for the use of forecast combinations generated from NN models in the estimation of corporate bankruptcy probabilities as it outperforms the standard approach of forming a hybrid forecasting model which includes all the explanatory variables. Copyright © 2012 John Wiley & Sons, Ltd.
PolyIC GE11 polyplex inhibits EGFR‐overexpressing tumors
Authors: Abourbeh Galith , Shir Alexei , Mishani Eyal , Ogris Manfred , Rödl Wolfgang , Wagner Ernst , Levitzki Alexander 
Published: February 2012

AbstractPhage display has identified the dodecapeptide YHWYGYTPQNVI (GE11) as a ligand that binds to the epidermal growth factor receptor (EGFR) but does not activate the receptor. Here, we compare the EGFR binding affinities of GE11, EGF, and their polyethyleneimine‐polyethyleneglycol (PEI‐PEG) conjugates. We found that although GE11 by itself does not exhibit measurable affinity to the EGFR, tethering it to PEI‐PEG increases its affinity markedly, and complex formation with polyinosine/cytosine (polyIC) further enhances the affinity to the submicromolar range. PolyIC/PPGE11 has a similar strong antitumor effect against EGFR overexpressing tumors in vitro and in vivo, as polyIC/polyethyleneimine‐polyetheleneglycol‐EGF (polyIC/PP‐EGF). Absence of EGFR activation, as previously shown by us and easier production of GE11 and GE11 conjugates, confer polyIC/PPGE11 a significant advantage over similar EGF‐based polyplexes as a potential therapy of EGFR overexpressing tumors. © 2012 IUBMB Life, 64(4): 324–330, 2012
Type III polyketide synthases in natural product biosynthesis
Authors: Yu Dayu , Xu Fuchao , Zeng Jia , Zhan Jixun 
Published: February 2012

AbstractPolyketides represent an important class of biologically active and structurally diverse compounds in nature. They are synthesized from acyl‐coenzyme A substrates by polyketide synthases (PKSs). PKSs are classified into three groups: types I, II, and III. This article introduces recent studies on type III PKSs identified from plants, bacteria, and fungi, and describes the catalytic functions of these enzymes in detail. Plant type III PKSs have been widely studied, as exemplified by chalcone synthase, which plays an important role in the synthesis of plant metabolites. Bacterial type III PKSs fall into five groups, many of which were identified from Streptomyces, a genus that has been well known for its production of bioactive molecules and genetic alterability. Although it was believed that type III PKSs exist exclusively in plants and bacteria, recent fungal genome sequencing projects and biochemical studies revealed the presence of type III PKSs in filamentous fungi, which provides a new chance to study fungal secondary metabolism and synthesize “unnatural” natural products. Type III PKSs have been used for the biosynthesis of novel molecules through precursor‐directed and structure‐based mutagenesis approaches. © 2012 IUBMB Life, 64(4): 285–295, 2012
Evaluation of the performance of Trima Accel® v5.2 for the collection of concentrated high‐dose platelet products and concurrent plasma from high platelet count donors, in germany
Authors: Daskalakis M. , Schulz‐Huotari C. , Burger M. , Klink I. , Umhau M. 
Published: February 2012

AbstractBackground and objectives: This study was undertaken to test the ability of Trima Accel® version 5.2 to simultaneously collect concentrated high‐dose leukoreduced platelet products and double doses of plasma. Materials and methods: Random volunteers (18–65 years of age) with preprocedure platelet counts above 270 × 103/μl were recruited among the blood center's apheresis donors. All complied with the center's donor selection criteria. Results: One hundred fourteen (114) collections were performed. Depending on which definition of single platelet dose is used (2.0 × 1011 as prevalent standard in most European countries, and 3.0 × 1011 as prevalent standard in the United States and Canada) in 107/114 (single dose = 2.0 × 1011) and 39/114 (single dose = 3.0 × 1011) instances, a triple platelet product was obtained. In 87 cases (76%), a double plasmaproduct (>430 ml) was collected, and in seven cases (6%), a single plasma product (>220 ml) was collected. In 20 procedures, only platelets without concurrent plasma were collected (18%). Overall procedure time was 87 ± 13 min and average platelet yield per procedure was 8.5 ± 1.4 × 1011 (final storage concentration, 1,279 ± 153 × 103/μl). The median residual leukocyte content per transfusion dose was 0.13 × 106 (0.02–0.98 × 106) for a single dose of 2.0 × 1011 and 0.14 × 106 (0.02–0.98 × 106) for a single dose of 3.0 × 1011. Conclusions: Trima Accel® version 5.2 allows for collection of concentrated high yield platelet products. It offers high productivity and reliably achieves the configured yield targets. Leukoreduction performance complied with both US and EU legal requirements. Collection as hyperconcentrates furthermore allowed for concurrent collection of double dose plasma in the majority of the procedures. J. Clin. Apheresis, 2012. © 2012 Wiley Periodicals, Inc.
Criteria and scheduling of quality control of b‐mode and doppler ultrasonography equipment
Authors: Balbis Sonia , Meloni Teodoro , Tofani Santi , Zenone Flora , Nucera Daniele , Guiot Caterina 
Published: February 2012

AbstractPeriodic quality control (QC) for ultrasound scanners checks their overall performance, reducing the risk of inaccurate diagnoses. Data from routine annual QC activity were analyzed to optimize the scheduling and the criteria of further QC programs. Among all the ultrasound scanners (68 transducers) in use at the Regional Medical Department of the Aosta Valley, which are currently tested, 48.6% showed problems, mainly (35.3%) related to defects detectable by physical and mechanical inspection. Nearly two‐thirds of these problems impacted QC parameters. Failures were significantly related to the workload and to the “technological level” of the equipment. QC scheduling should therefore include a daily/weekly physical inspection in addition to a more complete, objective and software algorithms‐based test, the frequency of which should be tailored on the basis of the equipment characteristics. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 2012
Molecular imaging of drug‐eluting coronary stents: method development, optimization and selected applications
Authors: Huang Jiun‐Tang , Hannah‐Qiuhua Li , Szyszka Renata , Veselov Vladimir , Reed Gail , Wang Xiande , Price Sylvester , Alquier Lori , Vas Gyorgy 
Published: February 2012

A molecular imaging application was developed to characterize the drug distribution on CYPHER® and NEVO™ Drug‐eluting Stents using MALDI Qq‐ToF analytical methodology. The coating matrix, laser energy, laser frequency, spatial resolution (related to rastering speed) and mass spectrometer parameters were optimized to analyze drug distribution in both durable and biodegradable polymer matrices. The developed method was extended to generate data from stents explanted from porcine coronary arteries.Due to the method's intrinsic specificity, it offers a significant advantage over other techniques in that it allows low‐level detection of the target molecule without biological interferences from the blood or tissue. The method is also capable of detecting drug‐related degradation products both from the finished stent product and from explanted stents. Copyright © 2012 John Wiley & Sons, Ltd.
2,5‐Piperazinedione inhibits quorum sensing‐dependent factor production in Pseudomonas aeruginosa PAO1
Authors: Musthafa Khadar Syed , Balamurugan Krishnaswamy , Pandian Shunmugiah Karutha , Ravi Arumugam Veera 
Published: February 2012

AbstractThe effects of 2,5‐piperazinedione in reducing the production of quorum sensing (QS)‐dependent factors in Pseudomonas aeruginosa PAO1 were assessed both in vitro and in vivo. 2,5‐Piperazinedione exhibited a 69% reduction in the azocasein‐degrading proteolytic activity and a 48% reduction in the elastolytic activity of PAO1. Further, it showed 85% and 96% reduction in the production of pyocyanin and extracellular polymeric substances (EPS) of PAO1, respectively. In the swimming inhibition assay, 2,5‐piperazinedione‐treated PAO1 cells exhibited poor swimming motility in swim agar medium. In the in vivo analysis, an enhanced survival of PAO1‐preinfected Caenorhabditis elegans was observed after treatment with 2,5‐piperazinedione. Regarding the mode of action, in the molecular docking analysis, 2,5‐piperazinedione interacts with the amino acid residue of the LasR receptor protein required for binding the natural ligand N ‐3‐oxododecanoyl‐l‐homoserine lactone (3‐oxo‐C12‐HSL). This demonstrates the probability of 2,5‐piperazinedione to interfere with the binding process of 3‐oxo‐C12‐HSL to its receptor protein. Thus, the findings of the present study reveal the potential of 2,5‐piperazinedione in reducing the QS‐dependent phenotypic features of PAO1. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)