bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel and Simple Molecular Probe Sensing Hg(II) in Living Cells by Chelation‐enhanced Fluorescence
Authors: Meng Qinghua , Cheng Sen , Lan Minbo , Wei Gang 
Published: January 2012

AbstractMercury is currently widely used in industries which leads to various means of Hg(II) waste exposure and its accumulation in organisms will cause neurological damages. Thus, there is a great need for the design of probes or sensors with high sensitivity and selectivity for detecting and monitoring Hg(II) at physiological pH. Thus a novel and simple molecular probe P1 was prepared from 1,1′‐(1,3‐phenylene)‐bis(2,4‐pentanedionato) for sensing Hg(II) via chelation‐enhanced fluorescence (CHEF) mechanism. The probe indicated a selectively fluorescent response to Hg(II) in aqueous media excited by the ultraviolet light of 254 nm. The recognition mechanism was further studied by semi‐empirical AM1 and molecular mechanics MM+ methods in HyperChem 8.0. The calculation indicated a tetrahedron coordination geometry for Hg(II) and a chair‐like configuration for the total molecule. The fluorescent images sensing Hg(II) in living mouse fibroblast cells by the probe were obtained by fluorescence microscope.
Chiral (6,3) Network Assembled by Lanthanide and Changeful Dihydroxyfumaric Acid
Authors: Zhang Manbo , Lü Jing , Hu Ruixiang 
Published: January 2012

AbstractA series of chiral two‐dimensional lanthanide coordination polymers, [Ln2(L)3(H2O)6]n·n/3H2O [Ln=Nd (1a, 1b), Sm (2), Eu (3), Tb (4), Dy (5), Ho (6), Er (7); H2L=2,2‐dihydroxylmalonic acid], have been hydrothermally synthesized by using dihydroxyfumaric acid as a source of polydentate O‐donor ligands. The luminescence behaviors of 3 and 4 have been investigated, and they exhibit strong red and green fluorescence in the visible region respectively.
Synthesis, Antibacterial Activities and Nuclease Properties of Ternary Copper(II) Complex Containing 2‐(2′‐Pyridyl)benzothiazole and Glycinate
Authors: Lu Yanmei , Chen Yongheng , Ou Zhibin , Chen Shi , Zhuang Chuxiong , Le Xueyi 
Published: January 2012

AbstractA new ternary complex [Cu(PBT)(Gly)(H2O)]ClO4 (PBT=2‐(2′‐pyridyl)benzothiazole, and Gly=glycinate) has been synthesized and characterized by elemental analysis, molar conductivity, and IR methods. The complex, structurally characterized by single‐crystal X‐ray crystallography, shows a slightly distorted square‐pyramidal coordination geometry in which two nitrogen atoms of PBT and the carboxylate oxygen atom O and the amino nitrogen atom N of Gly bind at the basal plane, a water molecule is coordinated at the apical position. The complex, Cu(ClO4)2 and free PBT were each tested for their ability to inhibit the growth of two Gram(−) (Escherichia coil, Salmonella) and two Gram(+) (Bacillus subtilis, Staphylococcus aureus) microorganisms. The complex showed good antibacterial activities against the microorganisms compared with free PBT and Cu(ClO4)2. The interaction between the complex and calf thymus DNA in aqueous solution was investigated using electronic spectroscopy, fluorescence spectroscopy, circular dichroic spectroscopy, and viscosity measurements. Results suggest that the complex could bind to DNA by an intercalative mode. In addition, the result of agarose gel electrophoresis showed that the complex can cleave the plasmid DNA by hydroxyl radicals and singlet oxygen‐like species under the condition of physiological pH and room temperature.
A Rapid and Simple Method for Quantitative Aziridination from Aminobrominated Derivatives of Olefins under Solvent‐free and Mild Conditions
Authors: Wei Junfa , Chen Zhanguo , Gao Yanni , Zhang Peng , Wang Chuanning , Zhao Pengfei , Wang Yun , Shi Xianying 
Published: January 2012

AbstractThe urea‐catalyzed aziridination of 1,2‐vicinal haloamines derived from aminohalogenation of olefins has been developed. This rapid and simple method was carried out by simply grinding the solid mixture of the substrate, K2CO3 and catalytic amount of urea at room temperature in air. The reaction provides a protocol for quantitative preparation of aziridines in a large scope of aminohalogenated derivatives of olefins including α,β‐unsaturated ketones, α,β‐unsaturated esters and simple olefins. The possible mechanism involving an H‐bond promoting deprotonation has been suggested for this reaction.
Recent Advances in the Total Synthesis of Chlorosulfolipids
Authors: Nilewski Christian , Carreira Erick M. 
Published: January 2012

AbstractFirst isolated in the late 1960s from microalgae of theOchromonas species, the chlorosulfolipids were largely considered as intractable synthetic challenges until recently. Indeed, only in the last few years has this class of natural products received intense attention from the synthetic community, motivated by the many interdisciplinary questions these entities raise. As a consequence, the numerous synthetic and spectroscopic studies that have appeared have contributed to a better understanding of the chemistry of chlorosulfolipids. More than forty years after their discovery, their mysteries are being revealed through the implementation of synthetic tactics and strategies. This microreview summarizes the progress in the synthesis and study of these fascinating natural products.
Voltammetric Ion‐Selective Nanocomposite Carbon Paste Electrode for Determination of Erbium at the Interface Between two Immiscible Electrolyte Solutions
Authors: Mirshafian R. , Norouzi P. , Ganjali M. R. 
Published: January 2012

AbstractIn this study for the first time a novel erbium(III) voltammetric ion‐selective nanocomposite carbon‐paste electrode was introduced based on the concept of ion transfer at the interface between two immiscible electrolyte solutions. N′‐(2‐hydroxy‐1,2‐diphenylethylidene) benzohydrazide (HDB) was used as a selective ionophore in the composition of the carbon paste. The ionophore facilitates transfer of Er(III) from the aqueous solution to the room temperature ionic liquid (RTIL) phase after reduction of the redox probe to maintain charge neutrality. The plot of the peak potential versus the logarithm of the concentration exhibits a Nernstian response (19.9±0.2 mV decade−1) toward Er(III) in the range of 7.5×10−7–1.0×10−1 mol L−1 with detection limit of 5.0×10−7 mol L−1. The proposed sensor shows a fast response time of about 5 s.
Differential cell proliferation in the cortex of the appsweps1de9 alzheimer's disease mouse model
Authors: Kamphuis Willem , Orre Marie , Kooijman Lieneke , Dahmen Maurice , Hol Elly M. 
Published: January 2012

AbstractPlaque deposition in Alzheimer's disease (AD) is known to decrease proliferation in neurogenic niches in AD mouse models, but the effects on cell proliferation and differentiation in other brain areas have not been studied in detail. We analyzed cell proliferation in the cortex of wild type (WT) and APPswePS1dE9 transgenic (AD) mice at different ages. Mice were studied shortly after the last BrdU injection (BrdU[ST]). In AD mice, the number of proliferating cells increased fourfold, coinciding with plaque appearance and its associated reactive gliosis and activation of microglia. An increase in the number of BrdU[ST]‐cells expressing markers for activated microglia is underlying the enhanced proliferation. Cortical reactive astrocytes did not become proliferative since BrdU[ST]‐cells were negative for different astrocyte‐specific markers. The number of Olig2‐positive oligodendrocyte precursor cells was unchanged. Four weeks after the last BrdU application, the number of BrdU[LT]‐cells with an activated microglia signature was still enhanced in AD mice. None of the newborn cells had differentiated into oligodendrocytes, astrocytes, or neurons. On the basis of these observations, we conclude that amyloid plaque deposition increases proliferation of microglia around plaques but does not affect the proliferation of cortical oligodendrocyte precursor cells. No evidence was found for damage‐induced proliferation of reactive astrocytes or for a redirected neurogenesis from the subventricular zone. The proliferation of microglia contributes to the rapid accumulation of microglia around plaques and may play a role in limitating plaque expansion. © 2012 Wiley Periodicals, Inc.
Prediction of temperature variation within a snowpack in open areas and under different canopy covers
Authors: Altunkaynak Abdüsselam , Aydın Abdurrahim 
Published: January 2012

AbstractSnow temperature is a major component of many physical processes in a snowpack. The temperature and the change in temperature across a layer have a dominant effect on physical properties of snow grains as well as its hardness, strength, and failure resistance. In this study, temperature and snow cover thickness were measured during the snow season of 2007–2008 in 11 elevation classes and in three different sampling locations, one in an open area and two under different forest canopy covers for each class along Kartalkaya road, Bolu. Each sampling site was visited 44 times to collect data including snow depth, snow surface temperature, ground temperature, and temperature within snowpack at 20‐cm intervals. Seven different models are developed to determine snowpack temperature variations under forest canopy covers and in an open area with different leaf area index values. All models were performed using a multilayer perceptron (MP) method for the Bolu–Kartalkaya area, Turkey. MP approach constitutes a standard form of neural network modeling and can modify two‐layer linear perceptron methods using three and more layers. The ability of MP is to handle complex nonlinear interactions, which ease the natural process of modeling. This method can overcome complex computations using neuron networks, and they can easily nonlinearly link input and output variables. The predictive errors are determined on the basis of mean absolute error and mean square error criteria. The Nash–Sutcliffe sufficiency score showing compliance between observed and predicted values is also calculated. According to the mean absolute error, the mean square error, and the Nash–Sutcliffe sufficiency score criteria, the predictive errors are within reasonable error intervals, justifying the use of the developed MP models for engineering applications. Copyright © 2012 John Wiley & Sons, Ltd.
Loss of gene function as a consequence of human papillomavirus DNA integration
Authors: Schmitz Martina , Driesch Corina , Beer‐Grondke Katrin , Jansen Lars , Runnebaum Ingo B. , Dürst Matthias 
Published: January 2012

AbstractIntegration of the human papillomavirus (HPV) genome into the host chromatin is a characteristic step in cervical carcinogenesis. Integration ensures constitutive expression of the viral oncogenes E6 and E7 which drive carcinogenesis. However, integration has also an impact on host DNA. There is increasing evidence that integration not only occurs in fragile sites and translocation breakpoints but also in transcriptionally active regions. Indeed, a substantial number of integration sites actually disrupt host genes and may thereby affect gene expression. No doubt, even subtle changes in gene expression may influence the cell phenotype but small fold changes are difficult to quantify reliably in biopsy material. We have, therefore, addressed the question whether a complete loss of gene function that is insertional mutagenesis in combination with deletion or epigenetic modification of the second allele is also a phenomenon pertinent to cervical cancer. Out of the ten preselected squamous cell carcinomas analyzed, all viral integration sites were located within the intron sequences of known genes, giving rise to viral–cellular fusion transcripts of sense orientation. Moreover, for two tumors, we provide evidence for complete functional loss of the gene affected by HPV integration. Of particular note is that one of the genes involved is the recently described novel tumor suppressor gene castor zinc finger 1. Although our study provides no functional proof that any of the genes affected by HPV integration are causally involved in the transformation process, an exhaustive systematic look at the role of insertional mutagenesis in cervical cancer appears to be warranted.
The proteolytic activity of MT4‐MMP is required for its pro‐angiogenic and pro‐metastatic promoting effects
Authors: Host Lorin , Paye Alexandra , Detry Benoit , Blacher Silvia , Munaut Carine , Foidart Jean Michel , Seiki Motoharu , Sounni Nor Eddine , Noel Agnès 
Published: January 2012

AbstractMembrane‐type 4 matrix metalloprotease (MT4‐MMP) expression in breast adenocarcinoma stimulates tumor growth and metastatic spreading to the lung. However, whether these pro‐tumorigenic and pro‐metastatic effects of MT4‐MMP are related to a proteolytic action is not yet known. Through site directed mutagenesis MT4‐MMP has been inactivated in cancer cells through Glutamic acid 249 substitution by Alanine in the active site. Active MT4‐MMP triggered an angiogenic switch at day 7 after tumor implantation and drastically accelerated subcutaneous tumor growth as well as lung colonization in recombination activating gene‐1‐deficient mice. All these effects were abrogated upon MT4‐MMP inactivation. In sharp contrast to most MMPs being primarily of stromal origin, we provide evidence that tumor‐derived MT4‐MMP, but not host‐derived MT4‐MMP contributes to angiogenesis. A genetic approach using MT4‐MMP‐deficient mice revealed that the status of MT4‐MMP produced by host cells did not affect the angiogenic response. Despite of this tumor intrinsic feature, to exert its tumor promoting effect, MT4‐MMP requires a permissive microenvironment. Indeed, tumor‐derived MT4‐MMP failed to circumvent the lack of an host angio‐promoting factor such as plasminogen activator inhibitor‐1. Overall, our study demonstrates the key contribution of MT4‐MMP catalytic activity in the tumor compartment, at the interface with host cells. It identifies MT4‐MMP as a key intrinsic tumor cell determinant that contributes to the elaboration of a permissive microenvironment for metastatic dissemination.
Functional Paracyclophanes: Synthesis of [2.2]Paracyclophanemethyldithiocarbonates Using Thione–Thiol Rearrangement of S,O‐Dithiocarbonates (Benzyl Schönberg Rearrangement) at Mild Conditions
Authors: Frank Daniel , Nieger Martin , Friedmann Christian , Lahann Jörg , Bräse Stefan 
Published: January 2012

AbstractA pathway to benzylic [2.2]paracyclophane thiol derivatives was investigated using the benzyl Schönberg rearrangement.
The Structures of Three [2.2]Paracyclophane Derivatives with Anellated Four‐Membered Rings
Authors: Hopf Henning , Hinrichs Heino , Ernst Ludger , Jones Peter G. , Boekelheide Virgil 
Published: January 2012

AbstractThe structures of the three benzocyclobutenophanes 1 a, 1 b (2 stereoisomers), and 11 have been determined by NMR spectroscopy and X‐ray structural analysis. The preparation of 11 from 4,5‐diethynyl[2.2]paracyclophane (9) is described.
Diverse sensory inputs permit priming in the acidic saline model of hyperalgesia
Authors: Jasper L.L. , MacNeil B.J. 
Published: January 2012

AbstractBackgroundThe rodent acidic saline model of hyperalgesia uses repeat injections of acidic saline in the right lateral gastrocnemius muscle, spaced five days apart, to induce a persistent decrease in hindpaw withdrawal thresholds. The objective of this study was to determine if alternate injection sites would permit development of hyperalgesia.MethodsThe location of the first muscle injection was varied between 3 groups of rats to include the right lateral gastrocnemius, the right medial gastrocnemius or the left lateral gastrocnemius. All second injections were placed in the right lateral gastrocnemius.ResultsAs reported by others, placing both injections in the right lateral gastrocnemius produced a significant reduction in paw withdrawal thresholds 24 hours after the second injection (p < 0.05). Relocating the first injection to the right medial gastrocnemius or the left lateral gastrocnemius also produced significant reductions in paw withdrawal thresholds (p < 0.05 for both). Hyperalgesia was also observed if the first muscle injection was replaced with a systemic injection of lipopolysaccharide. Further experiments tested whether glia cells may contribute to the priming process. Pretreatment with minocycline prior to the first injection completely blocked the development of hyperalgesia but was ineffective if injected before the second injection.ConclusionsThese data indicate that anatomically diverse peripheral stimuli can converge within the central nervous system to produce hyperalgesia.
Pyrazolones as Building Blocks in Heterocyclic Synthesis: Synthesis of New Pyrazolopyran, Pyrazolopyridazine and Pyrazole Derivatives of Expected Antifungicidal Activity
Authors: Ramiz Mahmoud. M. M. , Hafiz Ibrahim. S. Abdel , Reheim Mohamed. A. M. Abdel , Gaber Hatem M. 
Published: January 2012

AbstractA series of new pyrazolone and pyrazole derivatives with expected antifungicidal activity have been prepared through the reactions 3‐phenyl‐1‐H‐pyrazol‐5(4H)‐one (3) and 4‐(dimethylaminomethylene)‐3‐phenyl‐1H‐pyrazol‐5(4H)‐one (5) with a variety of electrophilic reagents and nucleophilic reagents. The newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR and mass spectral studies.
Development of Polymeric Resin Ion‐exchanger Based Chloride Ion‐selective Electrode for Monitoring Chloride Ion in Environmental Water
Authors: Cheng Cheanyeh , Huang Zhu‐Ming , Chung Wen‐Yaw , Pijanowskad Dorota G. , Dawgul Marek 
Published: January 2012

AbstractA chloride ion‐selective electrode (ISE) membrane was developed by using a copolymeric ion‐exchanger resin (trimethyl ethenyl quaternary ammonium chloride polystyrene‐divinylbenzene copolymer resin, TMEQAC PSDVB), the ionophore ({μ‐[4,5‐Dimethyl‐3,6‐bis(dodecyloxy)‐1,2‐phenylene]}bis(mercury chloride), ETH9033), the plasticizer (bis(2‐ethylhexyl) sebacate, DOS), and the membrane substrate (polyvinylchloride, PVC). At 25 °C, the electrode exhibited an ideal Nernstian response of 59.2 mV/decade with the linear calibration concentration range from 1.0 × 10−4‐1.0 × 10−2 M (r2 = 0.9930). The limit of detection was 2.45 ppm (6.9 × 10−2 mM) and the measurement response time was less than 10 seconds. The working temperature range of electrode was 10‐45 °C. The working pH range for chloride ion measurement was 2.0‐11.0. Among the various anions examined in this work, only I−, SCN−, and MnO4− ions show significant interference to the electrode measurement. The chloride ISE can be used at least 72 days. The determination of chloride ion content in three kinds of environmental water sample with the electrode method was accurate (92‐95%) and precise (RSD < 4.4%) and did not show significance difference from the high‐performance liquid chromatography method.
Kinetics of Malachite Green Fading in Water‐ethanol‐1‐propanol Ternary Mixtures
Authors: Samiey Babak , Zafari Mahshid 
Published: January 2012

AbstractThe rate constant of malachite green (MG+) alkaline fading was measured in water‐ethanol‐1‐propanol ternary mixtures. This reaction was studied under pseudo‐first‐order conditions at 283‐303 K. It was observed that the reaction rate constant increases in the presence of different weight percentages of ethanol and 1‐propanol. The fundamental rate constants of MG+ fading in these solutions were obtained by SESMORTAC model. In each series of experiments, concentration of one alcohol was kept constant and the concentration of the second one was changed. It was observed that at constant concentration of one alcohol and variable concentrations of the second one, with increase in temperature, k1 values increase and this indicates that presence of ethanol (or 1‐propanol) increases dissolution of 1‐propanol (or ethanol) in the activated complex formed in these solutions. Also, in each zone, fundamental rate constants of reaction at each certain temperature change as k2 » k1 » k−1.
Kinetics and Protein‐Inhibitor Docking Studies of Enantiomers of exo‐2‐Norbornyl‐N‐n‐butylcarbamates as Pseudomonas Lipase Inhibitors to Probe the Enantioselectivity of the Enzyme
Authors: Shen Yu‐Fang , Lin Gialih 
Published: January 2012

AbstractThe Pseudomonas species lipase inhibition shows enantioselectivity for R‐enantiomer over S‐enantiomer of exo‐2‐norbornyl‐N‐n‐butylcarbamates. R‐, S‐, and racemic‐exo‐2‐norbornyl‐N‐n‐butylcarbamates are all characterized as pseudo substrate inhibitors of the enzyme. Thus, the mechanism for Pseudomonas species lipase‐catalyzed hydrolysis of the inhibitor is formation of the first enzyme‐inhibitor Michaelis complex via nucleophilic attack of the active site serine to the inhibitor (Ki step) then formation of the butylcarbamyl enzyme intermediate from this complex (k2 step). Comparison of bimolecular rate constants (ki = k2 / Ki) of the inhibitors indicates that R‐enantiomer is 1.8 times more potent than S‐enantiomer. Thus, Pseudomonas species lipase shows enantioselectivity of 1.8 for R‐exo‐2‐norbornyl‐N‐n‐butyl‐carbamate over S‐exo‐2‐norbornyl‐N‐n‐butylcarbamate. Protein‐ligand interaction studies on both enantiomers of exo‐2‐norbornyl‐N‐n‐butylcarbamate as inhibitors of Pseudomonas species lipase using AutoDock suggest that R‐enantiomer binds more tightly into the active site of the enzyme than S‐enantiomer. The norbornyl ring of S‐exo‐2‐norbornyl‐N‐n‐butylcarbamate is repulsive to Ser 82 and His 251 of the catalytic triad as well as to Met 16 of the oxyanion hole. These repulsions may create few unfavorable interactions between S‐exo‐2‐norbornyl‐N‐n‐butylcarbamate and the enzyme and make this inhibitor a less potent one.
New Application of Chemically Modified Multiwalled Carbon Nanotubes with Thiosemicarbazide as a Sorbent for Separation and Preconcentration of Trace Amounts of Co(II), Cd(II), Cu(II), and Zn(II) in Environmental and Biological Samples Prior to Determination by Flame Atomic Absorption Spectrometry
Authors: Tavallali Hossein , Abdardideh Dawood , Aalaei Mehdi , Zahmatkesh Saeed 
Published: January 2012

AbstractThe present article reports the application of Thiosemicarbazide‐modified multiwalled carbon nanotubes (MWCNTs‐TSC) as a new, easily prepared selective and stable solid sorbent for the preconcentration of trace Co(II), Cd(II), Cu(II) and Zn(II) ions in aqueous solution prior to the determination by flame atomic absorption spectrometry. The studied metal ions can be adsorbed quantitatively on MMWNTs at pH 5.0 and then eluted completely with HNO3 (1.5 mol L−1) prior to their determination by flame atomic absorption spectrometry. The separation/preconcentration conditions of analytes were investigated, including the pH, the sample flow rate and volume, the elution condition and the interfering ions. The maximum adsorption capacity of the adsorbent at optimum conditions were found to be 32.5, 27.3, 44.5 and 34.1 mg g−1 for Co(II), Cd(II), Cu(II) and Zn(II), and the detection limits of the method were found to be 0.28, 0.13, 0.21 and 0.17 μg L−1, respectively. The proposed method was successfully applied for extraction and determination of the analytes in well water, sea water, wastewater, soil, and blood samples.