bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Sensitive, Label‐Free, Aptamer‐Based Biosensor Using a Gold Nanoparticle‐Initiated Chemiluminescence System
Authors: Qi Yingying , Li Baoxin 
Published: December 2010

AbstractWe report a label‐free, aptamer‐based chemiluminescent biosensor. The biosensor relies upon the catalytic activity of unmodified gold nanoparticles (AuNPs) on the luminol–H2O2 chemiluminescence (CL) reaction, and the interaction of unmodified AuNPs with the aptamer. The unmodified AuNPs can effectively differentiate unstructured and folded aptamer. The binding of the aptamer with the target can induce the AuNP aggregation in the presence of 0.5 M NaCl, and after aggregation the catalytic activity of the AuNPs on the luminol–H2O2 CL reaction is greatly enhanced. During the assay, no covalent functionalization of the AuNPs or aptamer is required. The detection limit of thrombin was estimated to be as low as 26 fM, and the sensitivity was more than 4 orders of magnitude better than that of known AuNP‐based colorimetric methods for the detection of thrombin. This aptamer‐based biosensor offers the advantages of being simple, cheap, rapid, and sensitive
Dynamics Effects on an E2/E1cb Borderline Mechanism: Unimolecular Elimination of 2‐Aryl‐3‐chloro‐2‐R‐propanols
Authors: Itoh Shuhei , Yamataka Hiroshi 
Published: December 2010

AbstractThe mechanistic dichotomy between concerted E2 and stepwise E1cb of the base‐promoted elimination of 2‐aryl‐3‐chloro‐2‐R‐propanols was examined computationally at the HF, M05‐2X, and MP2 levels of theory. Optimizations of transition states (TSs) and reaction intermediates, and intrinsic reaction coordinates (IRC) calculations showed that there was a single reaction route for each substrate, and that the mechanism could be changed from E2 to E1cb by making a carbanion intermediate more stable through the introduction of electron‐withdrawing substituents. Molecular dynamics simulations revealed that trajectories started at a single TS led directly to two product regions; the carbanion intermediate region in the E1cb mechanism, and the alkene product region in the E2 mechanism, through path bifurcation after the TS. The present system is a new example of bifurcation in reactions of closed‐shell molecules. The overall reaction mechanism changes dynamically from E2 to E1cb by a gradual change in the ratio of E2 and E1cb trajectories, rather than a path switch in concurrent pathways.
The Synthesis of (Z)‐Trisubstituted Allylic Alcohols by the Selective 1,4‐Hydrogenation of Dienol Esters: Improved Synthesis of (−)‐β‐Santalol
Authors: Fehr Charles , Magpantay Iris , Vuagnoux Magali , Dupau Philippe 
Published: December 2010

Abstract(E)‐Trisubstituted allylic alcohols are commonly prepared from the corresponding (E)‐enals, themselves readily accessible by a simple aldol condensation reaction. We demonstrate that these very same (E)‐enals can be converted into (Z)‐trisubstituted allylic acetates (and thus alcohols) by a ruthenium‐catalyzed 1,4‐hydrogenation of the corresponding dienol acetates. This simple solution to a long‐lasting problem was applied to an industrially feasible synthesis of (−)‐β‐santalol.
Synthesis of nanozeolite sodalite from rice husk ash without organic additives
Authors: Ghasemi Zahra , Younesi Habibollah , Kazemian Hossein 
Published: December 2010

AbstractRice husks are an excellent source of high‐grade amorphous silica which can be extracted from rice husk ash by a suitable alkali solution. The aim of this study is to synthesise nanozeolite sodalite by a hydrothermal method with extracted silica from rice husk as an agricultural waste without organic additives. The effect of crystallisation time on the properties of final products was investigated and the synthesised zeolite was characterised by XRD, SEM, EDX, FT‐IR, and BET techniques. Results revealed the significant effects of crystallisation time on the structural properties of nanozeolite. Synthesis of sodalite nanocrystal with crystallite size ranging from 30 to 60 nm was achieved at 60°C and aging of 5 h, without any organic additive.Le son de riz est une excellente source de silice amorphe de haute qualité qui peut être extraite des cendres de son de riz à l'aide d'une solution alcaline adaptée. L'objectif de la présente étude est de synthétiser les nanozéolites de sodalite au moyen d'une méthode hydrothermale, en extrayant, sans additifs organiques, de la silice à partir du son de riz (déchet agricole). L'effet du temps de cristallisation sur les propriétés des produits finaux a été étudié et la zéolite synthétisée a été analysée grâce aux techniques de DRX, MEB, EDX, FT‐IR, et BET. Les résultats ont révélé les effets significatifs du temps de cristallisation sur les propriétés structurelles des nanozéolites. La synthèse des nanocristaux de sodalite, avec une taille de cristallite allant de 30 à 60 nm, a été réalisée à une température de 60°C et après 5 heures, sans aucun additif organique. © 2010 Canadian Society for Chemical Engineering
Transformation of rat intestinal epithelial cells by overexpression of Rab25 is microtubule dependent
Authors: Lapierre Lynne A. , Caldwell Cathy M. , Higginbotham James N. , Avant Kenya M. , Hall Janine , Daniel Beauchamp R. , Goldenring James R. 
Published: December 2010

AbstractLittle research has addressed the role of membrane trafficking and recycling in the regulation of the transformed phenotype of neoplastic cells. The small GTPase Rab25 is an epithelial‐specific modulator of membrane recycling. Recent studies have demonstrated that Rab25 expression is up‐regulated in a number of epithelial cancers and overexpression may increase the aggressive phenotype of certain cancers. We have utilized the nontransformed RIE cell line to examine the influence of Rab25 on transformation. Overexpression of Rab25 in RIE cells leads to morphological transformation as well as growth in soft agar, tumor formation in nude mice, disruption of integrin‐based focal adhesions, and alteration in modified microtubule subsets. Although the predominance of recent cancer research has focused on the manipulation of the actin‐based cytoskeleton, recycling trafficking relies on microtubules. Transformation of RIE cells through overexpression of Rab25, but not with H‐RasV12, was reversed by inhibitors of microtubule polymerization. These results suggest that up‐regulation of Rab25 in RIE cells leads to microtubule‐dependent transformation. Thus, depolymerization of microtubules may be a potent therapeutic target for cancer therapy through the reversal of the invasive phenotype of certain cancer cells. © 2011 Wiley‐Liss, Inc.
Discovery of 4‐Benzylamino‐Substituted α‐Carbolines as a Novel Class of Receptor Tyrosine Kinase Inhibitors
Authors: Krug Martin , Wichapong Kanin , Erlenkamp German , Sippl Wolfgang , Schächtele Christoph , Totzke Frank , Hilgeroth Andreas 
Published: December 2010

AbstractWithin the last decade, interest in the development of new anticancer drugs increased mainly from emerging resistance against established drugs, which were found to be limited by the multidrug resistance (MDR) phenomenon. Several anticancer targets have been investigated for the development of structurally new drugs which were thought to be unaffected by the MDR phenomenon. Receptor tyrosine kinases (RTKs) make up one interesting group of anticancer targets. The overexpression and mutation of RTKs lead to an ongoing stimulus of cell growth and cancer progression. Early approaches to selective inhibition of single RTKs were generally disappointing in clinical studies, due in part to occurring resistance. Therefore, a new strategy involves the identification of multi‐kinase inhibitors to slow the development of potential resistance. Moreover, the expected side effects of the first nonselective inhibitors were less dramatic than had been expected. We have discovered novel 4‐benzylamino‐α‐carbolines as a new class of RTK inhibitors. Docking studies suggest a binding mode to the addressed target structures of the epidermal growth factor receptor (EGFR) and to the vascular endothelial growth factor receptor 2 (VEGFR2). Selectivity profiling against a panel of kinases and antiproliferative studies have highlighted one inhibitor, active in the nanomolar range, as a highly interesting candidate for further clinical studies.
Magnetic resonance imaging of printed text
Authors: Hornak Joseph P. 
Published: December 2010

AbstractMany electrophotographic print engines use toner with ferromagnetic particles that become fused with the paper. When text printed with this toner is placed in a uniform magnetic field, the text distorts the field. Placing this text adjacent to a material with a spatially uniform magnetic resonance signal causes a distortion in the signal, thus making the text visible in a magnetic resonance image of the material. An example of this process is presented using electrophotographically printed text and an aqueous solution. Applications might include analysis of paintings. © 2010 Wiley Periodicals, Inc. Concepts Magn Reson Part A 36A: 347–348, 2010.
Systems biology of symmetry breaking during neuronal polarity formation
Authors: Inagaki Naoyuki , Toriyama Michinori , Sakumura Yuichi 
Published: December 2010

AbstractPolarization, in which a single axon and multiple dendrites are formed, is crucial for neuronal functions, and symmetry breaking is the initial step of this process. Accumulating studies have revealed a number of molecules that act asymmetrically in neurons, and thereby regulate neuronal polarity. Thus, one of the major goals of current research is to understand how asymmetric signals are generated during the symmetry‐breaking step. Current models of neuronal symmetry breaking generally involve “local activation” for induction of axon outgrowth and “global inhibition” to suppress formation of multiple axons and can be categorized into “one‐takes‐all” and “activator–inhibitor” models. Both types of model incorporate a positive feedback loop to execute local activation, but differ in the manner of global inhibition. Quantitative experimentation combined with computational modeling is a powerful strategy in systems biology, and analyses in this direction have begun to yield a more profound understanding of how neurons break their symmetry during polarity formation. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 71: 584–593, 2011
The vertebrate retina: A model for neuronal polarization in vivo
Authors: Randlett Owen , Norden Caren , Harris William A. 
Published: December 2010

AbstractThe vertebrate retina develops rapidly from a proliferative neuroepithelium into a highly ordered laminated structure, with five distinct neuronal cell types. Like all neurons, these cells need to polarize in appropriate orientations order integrate their neuritic connections efficiently into functional networks. Its relative simplicity, amenability to in vivo imaging and experimental manipulation, as well as the opportunity to study varied cell types within a single tissue, make the retina a powerful model to uncover how neurons polarize in vivo. Here we review the progress that has been made thus far in understanding how the different retinal neurons transform from neuroepithelial cells into mature neurons, and how the orientation of polarization may be specified by a combination of pre‐established intrinsic cellular polarity set up within neuroepithelial cells, and extrinsic cues acting upon these differentiating neurons. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 71: 567–583, 2011
Neuronal polarity in C. elegans
Authors: Ou Chan‐Yen , Shen Kang 
Published: December 2010

AbstractNeuronal polarity sets the foundation for information processing and signal transmission within neural networks. However, fundamental question of how a neuron develops and maintains structurally and functionally distinct processes, axons and dendrites, is still an unclear. The simplicity and availability of practical genetic tools makes C. elegans as an ideal model to study neuronal polarity in vivo. In recent years, new studies have identified critical polarity molecules that function at different stages of neuronal polarization in C. elegans. This review focuses on how neurons guided by extrinsic cues, break symmetry, and subsequently recruit intracellular molecules to establish and maintain axon‐dendrite polarity in vivo. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 71: 554–566, 2011
Compartmentalization within neurites: Its mechanisms and implications
Authors: Katsuki Takeo , Joshi Rajshri , Ailani Deepak , Hiromi Yasushi 
Published: December 2010

AbstractNeurons are morphologically characterized by long processes extending from a cell body. These processes, the dendrites and axon, are major sub‐cellular compartments defined by morphological, molecular, and functional differences. However, evidence from vertebrates and invertebrates suggests that, based on molecular distribution, individual axons and dendrites are further divided into distinct compartments; many membrane molecules involved in axon guidance and synapse formation are localized to specific segments of axons or dendrites that share a boundary of localization. In this review, we describe recent progress in understanding the mechanisms of intra‐neurite patterning, and discuss its potential roles in the development and function of the nervous system. Each protein employs different ways to achieve compartment‐specific localization; some membrane molecules localize via cell‐autonomous ability of neurons, while others require extrinsic signals for localization. The underlying regulatory mechanisms include transcriptional regulation, local translation, diffusion barrier, endocytosis, and selective membrane targeting. We propose that intra‐neurite compartmentalization could provide platforms for structural and functional diversification of individual neurons. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 71:458–473, 2011
Regulated expression of transgenes in embryonic stem cell‐derived neural cells
Authors: Lorberbaum David S. , Gottlieb David 
Published: December 2010

AbstractDiscovery and characterization of gene promoters, enhancers and repressor binding elements is an important research area in neuroscience. Here, the suitability of embryonic stem cells and their neural derivatives as a model system for this research is investigated. Three neural transgenic constructs (from the Mnx1, Fabp7, and tuba1a genes) that have been validated in transgenic mice were inserted into embryonic stem cells as stable transgenes. These transgenic embryonic stem cells were differentiated into neural cultures and the pattern of transgene expression across a series of inducing conditions determined. The pattern of expression matched that predicted from transgenic mouse experiments for each of the three transgenes. The results show that embryonic stem cells and their neural derivatives comprise a promising model for investigating the mechanisms that control cell‐ and temporal‐specific neural gene transcription. genesis 49:66–74, 2011. © 2010 Wiley‐Liss, Inc.
Reconstructing embryonic development
Authors: Khairy Khaled , Keller Philipp J. 
Published: December 2010

AbstractNovel approaches to bio‐imaging and automated computational image processing allow the design of truly quantitative studies in developmental biology. Cell behavior, cell fate decisions, cell interactions during tissue morphogenesis, and gene expression dynamics can be analyzed in vivo for entire complex organisms and throughout embryonic development. We review state‐of‐the‐art technology for live imaging, focusing on fluorescence light microscopy techniques for system‐level investigations of animal development, and discuss computational approaches to image segmentation, cell tracking, automated data annotation, and biophysical modeling. We argue that the substantial increase in data complexity and size requires sophisticated new strategies to data analysis to exploit the enormous potential of these new resources. genesis 49:488–513, 2011. © 2010 Wiley‐Liss, Inc.
Reactivity of Quinones with Phosphagermaallene Tip(tBu)Ge=C=PMes* Leading to Four‐ and Six‐Membered Heterocycles with an Exocyclic P=C Double Bond
Authors: Ghereg Dumitru , Gornitzka Heinz , Escudié Jean 
Published: December 2010

AbstractPhosphagermaallene Tip(tBu)Ge=C=PMes* (1) (Tip = 2,4,6‐triisopropylphenyl, Mes* = 2,4,6‐tri‐tert‐butylphenyl) reacts with one equivalent of p‐quinone (1,4‐benzoquinone, 2,3,5,6‐tetramethyl‐1,4‐benzoquinone, 1,4‐naphthoquinone, and 9,10‐anthraquinone) to form spiro 1‐oxa‐2‐germacyclobutane compounds 2–5 with an exocyclic P=C double bond by [2 + 2] cycloaddition between the Ge=C and one of the C=O double bonds. With two equivalents of 1 a double [2 + 2] cycloaddition occurs involving both unsaturated C=O bonds of 1,4‐benzoquinone to give the dispiro compound 6. [2 + 4] Cycloadditions are observed between the Ge=C double bond of 1 and the O=C–C=O unit of an α‐diketone (benzil) and an o‐quinone (9,10‐phenanthrenequinone) to give the corresponding 1,4‐dioxa‐2‐germa‐5‐cyclohexenes 7 and 8.
In Situ Synthesis of Chlorinated Fullerenes by the High‐Frequency Furnace Method
Authors: Mueller Andreas , Ziegler Karolin , Amsharov Konstantin Yu. , Jansen Martin 
Published: December 2010

AbstractExohedrally chlorinated fullerenes have been synthesized by in situ chlorination using the high‐frequency furnace method in the presence of carbon tetrachloride as reagent. In addition to the previously reported chlorinated non‐IPR (isolated pentagon rule) fullerene cages of C2nCl2m (n = 25, 27, 28, 30, 32 and 33, m = 2–6), a C68 and various new higher fullerenes including C2nCl2m with n = 36, 37 and 39 were present in the soot extracts in significant quantities, as shown by HPLC/off‐line mass spectrometric analyses. A more detailed analysis showed the presence of several species with the same carbon content that could arise from either the formation of different isomers or different degrees of chlorination.
Land‐use change emissions: How green are the bioplastics?
Authors: Piemonte Vincenzo , Gironi Fausto 
Published: December 2010

AbstractRecently, a discussion has emerged around greenhouse gas emissions due to direct and indirect land use change (LUC) of expanding agricultural areas dedicated to bio‐products production. Converting rainforests, peatlands, savannas, or grasslands to produce food crop‐based bio‐products creates a “carbon debt” by releasing 9 to 170 times more CO2 than the annual greenhouse gas (GHG) reductions that these bio‐products (such as the bioplastics) would provide by displacing petroleum‐based products (conventional plastics). In this work, we demonstrate the importance of accounting for the LUC emissions in the LCA studies devoted to the analysis of the environmental impact of bio‐based products and in particular of the bioplastics. To this end, an original case study has been carried out on the comparison between the LCAs of shoppers made from Mater‐Bi (corn‐based bioplastic) and polyethylene, including the LUC emissions. The obtained results highlight the strong influence of the LUC emissions on the GHGs saving achievable by displacing petroleum‐based plastics with bioplastics and point out the importance of using waste biomass or biomass grown on degraded and abandoned agricultural lands to produce bioplastics that, in this manner, can offer immediate and sustained GHG advantages. © 2010 American Institute of Chemical Engineers Environ Prog, 2010
Can sediment total organic carbon and grain size be used to diagnose organic enrichment in estuaries?
Authors: Pelletier Marguerite C , Campbell Daniel E , Ho Kay T , Burgess Robert M , Audette Charles T , Detenbeck Naomi E 
Published: December 2010

Abstract
Eutrophication (i.e., nutrient enrichment, organic enrichment, and oxygen depletion) is one of the most common sources of impairment in Clean Water Act 303(d)-listed waters in the United States. Although eutrophication can eventually cause adverse effects to the benthos, it may be difficult to diagnose. Sediment organic carbon (OC) content has been used as an indicator of enrichment in sediments, but the amount of surface area available for carbon adsorption must be considered. We investigated the utility of the relationship between OC and sediment grain size as an indicator of eutrophication. Data from the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program was used to test this relationship. However, anthropogenic contaminants are also capable of causing adverse effects to the benthos and often co-occur with elevated levels of OC. Contaminant analysis and toxicity tests were not consistently related to enrichment status as defined by relationship between total OC and grain size. Although variability in response occurred, reflecting the variance in the water column factors (dissolved oxygen, chlorophyll a, and nutrients) and limited sample sizes, the data supported the hypothesis that sites designated as enriched were eutrophied. Dissolved oxygen levels were reduced at enriched sites, whereas chlorophyll a and nutrients were higher at enriched sites. This suggests that the relationship of OC to grain size can be used as a screening tool to diagnose eutrophication. Environ. Toxicol. Chem. 2011; 30:538–547. © 2010 SETAC
Sublethal genotoxicity and cell alterations by organophosphorus pesticides in MCF-7 cells: Implications for environmentally relevant concentrations
Authors: Ukpebor Justina , Llabjani Valon , Martin Francis L , Halsall Crispin J 
Published: December 2010

Abstract
Organophosphorus pesticide (OPP) toxicity is believed to be mediated through inhibition of acetylcholinesterase (AChE). Given their widespread distribution in aquatic systems and their ability to undergo chemical transformation, their environmental impacts at sublethal concentrations in nontarget organisms have become an important question. We conducted a number of mammalian-cell genotoxic and gene expression assays and examined cellular biochemical changes that followed low-dose exposure of MCF-7 cells to fenitrothion, diazinon, and the aqueous degradate of diazinon, 2-isopropyl-6-methyl-4-pyrimidinol (IMP). After exposure to the OPPs at low concentrations (10−12 M to 10−8 M), greater than twofold elevations in micronucleus formation were noted in MCF-7 cell cultures that went on to exhibit greater than 75% clonogenic survival; these levels of chromosomal damage were comparable to those induced by 10−6 M benzo[a]pyrene, a known genotoxic agent. At this low concentration range, a fenitrothion-induced twofold elevation in B-cell leukemia/lymphoma-2 (BCL-2) and cytochrome P450 isoenzyme (CYP1A1) gene expressions was observed. Principal component analysis-linear discriminant analysis (PCA-LDA) of derived infrared (IR) spectra of vehicle control (nonexposed) and OPP-exposed cells highlighted that both fenitrothion and diazinon induced marked biochemical alterations in the lipid, protein, and DNA/RNA absorbance regions. Our findings demonstrate that the two OPP parent chemicals and IMP degradate can mediate a number of toxic effects or cellular alterations at very low concentrations. These are independent of just selective inhibition of AChE, with potential consequences for nontarget organisms exposed at environmentally relevant concentrations. Further assays on relevant aquatic organism cell lines are now recommended to understand the mechanistic low-dose toxicity of these chemicals present in aquatic systems. Environ. Toxicol. Chem. 2011; 30:632–639. © 2011 SETAC