A study of the vaporization enthalpies of some 1-substituted imidazoles and pyrazoles by correlation-gas chromatography.

Science.gov (United States)

Lipkind, Dmitry; Plienrasri, Chatchawat; Chickos, James S

2010-12-23

The vaporization enthalpies of 1-methyl-, 1-ethyl-, 1-phenyl-, and 1-benzylimidazole, 1-methyl- and 1-phenylpyrazole, and trans-azobenzene are evaluated by correlation-gas chromatography (C-GC) using a variety of azines and diazines as standards. The vaporization enthalpies obtained by C-GC when compared to literature values are approximately 14 kJ·mol(-1) smaller for the imidazoles and 6 kJ·mol(-1) smaller for the pyrazoles. The literature vaporization enthalpies of 1-methylpyrrole and 1-methylindole, two closely related compounds with one less nitrogen, are reproduced by C-GC. These results suggest that the magnitude of the intermolecular interactions present in 1-substituted imidazoles and pyrazoles are significantly larger than the those present in the reference compounds and greater than or equal in magnitude to the enhanced intermolecular interactions observed previously in aromatic 1,2-diazines. The vaporization enthalpy and vapor pressure of a trans-1,2-diazine, trans-azobenzene, measured by C-GC using similar standards reproduced the literature values within experimental error.

Comprehensive review in current developments of imidazole-based medicinal chemistry.

Science.gov (United States)

Zhang, Ling; Peng, Xin-Mei; Damu, Guri L V; Geng, Rong-Xia; Zhou, Cheng-He

2014-03-01

Imidazole ring is an important five-membered aromatic heterocycle widely present in natural products and synthetic molecules. The unique structural feature of imidazole ring with desirable electron-rich characteristic is beneficial for imidazole derivatives to readily bind with a variety of enzymes and receptors in biological systems through diverse weak interactions, thereby exhibiting broad bioactivities. The related research and developments of imidazole-based medicinal chemistry have become a rapidly developing and increasingly active topic. Particularly, numerous imidazole-based compounds as clinical drugs have been extensively used in the clinic to treat various types of diseases with high therapeutic potency, which have shown the enormous development value. This work systematically gives a comprehensive review in current developments of imidazole-based compounds in the whole range of medicinal chemistry as anticancer, antifungal, antibacterial, antitubercular, anti-inflammatory, antineuropathic, antihypertensive, antihistaminic, antiparasitic, antiobesity, antiviral, and other medicinal agents, together with their potential applications in diagnostics and pathology. It is hoped that this review will be helpful for new thoughts in the quest for rational designs of more active and less toxic imidazole-based medicinal drugs, as well as more effective diagnostic agents and pathologic probes. © 2013 Wiley Periodicals, Inc.

The lattice dynamics of imidazole

International Nuclear Information System (INIS)

Link, K.H.

1983-05-01

The lattice dynamics of imidazole have been investigated. To this end dispersion curves have been determined at 10 K by inelastic coherent neutron scattering. RAMAN measurements have been done to investigate identical gamma - point modes. The combination of extinction rules for RAMAN - and neutron scattering leads to the symmetry assignment of identical gamma - point modes. The experiment yields a force constant of the streching vibration of the hydrogen bond of 0.33 mdyn/A. A force model has been developed to describe the intermolecular atom - atom Interactions in imidazole. (orig./BHO)

Severity Classification of a Seismic Event based on the Magnitude-Distance Ratio Using Only One Seismological Station

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Luis Hernán Ochoa Gutiérrez

2014-07-01

Full Text Available Seismic event characterization is often accomplished using algorithms based only on information received at seismological stations located closest to the particular event, while ignoring historical data received at those stations. These historical data are stored and unseen at this stage. This characterization process can delay the emergency response, costing valuable time in the mitigation of the adverse effects on the affected population. Seismological stations have recorded data during many events that have been characterized by classical methods, and these data can be used as previous "knowledge" to train such stations to recognize patterns. This knowledge can be used to make faster characterizations using only one three-component broadband station by applying bio-inspired algorithms or recently developed stochastic methods, such as kernel methods. We trained a Support Vector Machine (SVM algorithm with seismograph data recorded by INGEOMINAS's National Seismological Network at a three-component station located near Bogota, Colombia. As input model descriptors, we used the following: (1 the integral of the Fourier transform/power spectrum for each component, divided into 7 windows of 2 seconds and beginning at the P onset time, and (2 the ratio between the calculated logarithm of magnitude (Mb and epicentral distance. We used 986 events with magnitudes greater than 3 recorded from late 2003 to 2008. The algorithm classifies events with magnitude-distance ratios (a measure of the severity of possible damage caused by an earthquake greater than a background value. This value can be used to estimate the magnitude based on a known epicentral distance, which is calculated from the difference between P and S onset times. This rapid (< 20 seconds magnitude estimate can be used for rapid response strategies. The results obtained in this work confirm that many hypocentral parameters and a rapid location of a seismic event can be obtained using a few

Synthesis of the zeolitic imidazolate framework ZIF-4 from the ionic liquid 1-butyl-3-methylimidazolium imidazolate

Science.gov (United States)

Hovestadt, Maximilian; Schwegler, Johannes; Schulz, Peter S.; Hartmann, Martin

2018-05-01

A new synthesis route for the zeolitic imidazolate framework ZIF-4 using imidazolium imidazolate is reported. Additionally, the ionic liquid-derived material is compared to conventional ZIF-4 with respect to the powder X-ray diffraction pattern pattern, nitrogen uptake, particle size, and separation potential for olefin/paraffin gas mixtures. Higher synthesis yields were obtained, and the different particle size affected the performance in the separation of ethane and ethylene.

Imidazole as a parent π-conjugated backbone in charge-transfer chromophores

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Jiří Kulhánek

2012-01-01

Full Text Available Research activities in the field of imidazole-derived push–pull systems featuring intramolecular charge transfer (ICT are reviewed. Design, synthetic pathways, linear and nonlinear optical properties, electrochemistry, structure–property relationships, and the prospective application of such D-π-A organic materials are described. This review focuses on Y-shaped imidazoles, bi- and diimidazoles, benzimidazoles, bis(benzimidazoles, imidazole-4,5-dicarbonitriles, and imidazole-derived chromophores chemically bound to a polymer chain.

Synthesis and characterization of some complexes with imidazole and pyrazole from saccharinate transition ions in oxidation state (II)

International Nuclear Information System (INIS)

Pineda Cedeno, Leslie William

2001-01-01

The synthesis and characterization of metal ions saccharinate of the first serie of transition with the imidazole and pyrazole molecules in water and absolute ethanol were studied. In general, it found that in this series of saccharinate of coordinated water molecules are replaced by imidazole and pyrazole molecules with different substitution patterns, generating neutral complex of molecular formula [M(Sac) 2 (L) n (H 2 O) n-4 ] and cationic complex of molecular formula [M(L) n (H 2 O) 2 ]x2Sac, [M(L) n (H 2 O) 3 ]x2Sac, [M(L) n ]x2Sac, where M = V(II), Cr(II), Mc(II), Fe(II), Co(II), Ni(II) y Zn(II); Sac = saccharinate ion; L = imidazole (imd) and pyrazole (pir) and n = 6,4,3 and 2. These compounds are soluble in DMF and insoluble in all other common solvents. In turn, synthesized compounds in water were characterized by X ray crystallography, where preliminary data of refinement cycles, generate formulas of isostructural type [M(imd) 4 (H 2 O) 2 ]x2Sac and [M(Sac) 2 (pir) 2 (H 2 O) 2 ] where M = Co(II), Ni(II). The imidazole complex crystallize in the triclinic crystal system and space group P-1, while the pyrazole complexes crystallize in the monoclinic crystal system and space group P2 (1)/n. Gradual diminution was observed in the bond distances of M-N (saccharinate ion), M-N (imidazole) and M-N (pyrazole). The complex was characterized by spectroscopic methods, magnetic and electrochemical. (author) [es

Multi-color light curves of type Ia supernovae on the color-magnitude diagram: A novel step toward more precise distance and extinction estimates

International Nuclear Information System (INIS)

Wang, Lifan; Goldhaber, Gerson; Aldering, Greg; Perlmutter, Saul

2003-01-01

We show empirically that fits to the color-magnitude relation of Type Ia supernovae after optical maximum can provide accurate relative extragalactic distances. We report the discovery of an empirical color relation for Type Ia light curves: During much of the first month past maximum, the magnitudes of Type Ia supernovae defined at a given value of color index have a very small magnitude dispersion; moreover, during this period the relation between B magnitude and B-V color (or B-Ror B-I color) is strikingly linear, to the accuracy of existing well-measured data. These linear relations can provide robust distance estimates, in particular, by using the magnitudes when the supernova reaches a given color. After correction for light curve stretch factor or decline rate, the dispersion of the magnitudes taken at the intercept of the linear color-magnitude relation are found to be around 0 m .08 for the sub-sample of supernovae with (B max - V max ) (le) 0 m 0.5, and around 0 m .11 for the sub-sample with (B max - V max ) (le) 0 m .2. This small dispersion is consistent with being mostly due to observational errors. The method presented here and the conventional light curve fitting methods can be combined to further improve statistical dispersions of distance estimates. It can be combined with the magnitude at maximum to deduce dust extinction. The slopes of the color-magnitude relation may also be used to identify intrinsically different SN Ia systems. The method provides a tool that is fundamental to using SN Ia to estimate cosmological parameters such as the Hubble constant and the mass and dark energy content of the universe

Complex-forming capacity of some biologically active imidazoles

Energy Technology Data Exchange (ETDEWEB)

Lenarcik, B; Wisniewski, M

1983-01-01

By using the potentiometric and spectrophotometric methods, formation of Co(2), Cu(2), Zn(2), Ni(2) and Cd(2) complexes of (3S-cis)-3-ethyl-dihydro-4-((1-methyl-1H-imidazol-5-yl)-methyl)-2(3H)-furanone (pilocarpine, PLC), 4,5-dihydro-2-(phenylmethyl)-1H-imidazole (tolazoline, TLZ), 2-methyl-5-nitro-1H-imidazole-1-ethanol (metronidazole, MET) and 1H-imidazole-4-ethanamine (histamine, HIST) was investigated. The stability constants, ..beta../sub n/, of these complexes were determined. It was shown that the electron-donor strength of the ligands was controlled by the heterocyclic nitrogen atom, and that the formation of the Zn(2)-PLC complex was accompanied by the change in the structure of the coordination sphere of the metal. With Cu(2), the PLC and TLZ ligands were shown to enhance the Jahn-Teller deformation.

The JHKs Magnitudes of the Red Giant Branch Tip and the Distance Moduli of Nearby Dwarf Galaxy NGC 205

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M. Y. Jung

2009-12-01

Full Text Available We have used the near-infrared JHKS photometric data of resolved stars in a nearby dwarf elliptical galaxy NGC 205 to determine the magnitudes of the red giant branch tip (TRGB. By applying Savitzky-Golay filter to the observed luminosity functions (LFs in each band, we derived the second derivatives of the LFs so as to determine the magnitudes of the TRGB. Absolute magnitudes of the TRGB in JHKs bands were measured from the Yonsei-Yale isochrones. By comparing the determined apparent magnitudes and the theoretical absolute magnitudes of the TRGB, we estimated the distance moduli of NGC 205 to be (m-M = 24.10±0:08, 24.08±0.12 and 24.14±0.14 in J, H, and Ks bands, respectively.

Study of the improvement of the radioprotective power of imidazole; Etude de l'amelioration du pouvoir radioprotecteur de l'imidazole

Energy Technology Data Exchange (ETDEWEB)

Mourret, A; Rinaldi, R [Commissariat a l' Energie Atomique, 38 - Grenoble (France). Centre d' Etudes Nucleaires

1968-07-01

In studies made on the Imidazole radioprotective power, the authors have attempted to neutralize its convulsive properties by the Depamide so as to decrease drug toxicity. Then, having studied in what manner the two products simultaneous action could carry one increase of radioprotective activity, they have established that if the Depamide permits to decrease very much the Imidazole toxicity, the variation of radioprotection power which is subject to animal sex, generally increases for females and decreases for males. (authors) [French] Dans le cadre de l'etude du pouvoir radioprotecteur de l'Imidazole, les auteurs ont essaye de neutraliser les proprietes convulsivantes de cette substance par le Depamide afin d'en dimunuer la toxicite. Ayant ensuite etudie dans quelle mesure l'action simultanee de ces deux produits pouvait apporter une amelioration de l'activite radioprotectrice, ils ont constate que si le Depamide permet de diminuer tres sensiblement la toxicite de l'Imidazole, la variation du pouvoir radioprotecteur, qui depend du sexe de l'animal, augmente en general pour les femelles et diminue pour les males. (auteurs)

Multi-color light curves of type Ia supernovae on thecolor-magnitude diagram: A novel step toward more precise distance andextinction estimates

Energy Technology Data Exchange (ETDEWEB)

Wang, Lifan; Goldhaber, Gerson; Aldering, Greg; Perlmutter, Saul

2003-01-31

We show empirically that fits to the color-magnituderelation of Type Ia supernovae after optical maximum can provide accuraterelative extragalactic distances. We report the discovery of an empiricalcolor relation for Type Ia light curves: During much of the first monthpast maximum, the magnitudes of Type Ia supernovae defined at a givenvalue of color index have a very small magnitude dispersion; moreover,during this period the relation between B magnitude and B-V color (or B-Ror B-I color) is strikingly linear, to the accuracy of existingwell-measured data. These linear relations can provide robust distanceestimates, in particular, by using the magnitudes when the supernovareaches a given color. After correction for light curve stretch factor ordecline rate, the dispersion of the magnitudes taken at the intercept ofthe linear color-magnitude relation are found to be around 0^m .08 forthe sub-sample of supernovae with (B_max - V_max) ?= 0^m 0.5, andaround 0^m.11 for the sub-sample with (B_max - V_max) ?= 0^m .2.This small dispersion is consistent with being mostly due toobservational errors. The method presented here and the conventionallight curve fitting methods can be combined to further improvestatistical dispersions of distance estimates. It can be combined withthe magnitude at maximum to deduce dust extinction. Theslopes of thecolor-magnitude relation may also be used to identify intrinsicallydifferent SN Ia systems. The method provides a tool that is fundamentalto using SN Ia to estimate cosmological parameters such as the Hubbleconstant and the mass and dark energy content of theuniverse.

Fast Estimation of Epicentral Distance and Magnitude from a Single Three Component Seismic Station Using Machine Learning Techniques

Science.gov (United States)

Ochoa Gutierrez, L. H.; Niño, L. F.; Vargas-Jimenez, C. A.

2013-05-01

To minimize adverse effects originated by high magnitude earthquakes, early warning has become a powerful tool to anticipate a seismic wave arrival to an specific location, bringing opportune information to people and government agencies to initiate a fast response. To do this, a very fast and accurate characterization of the event must be done but this process is often made using seismograms recorded in at least four stations where processing time is usually greater than the wave arrival time to the interest area, mainly in seismological coarse networks. A faster process can be done if only one three component seismic station, the closest unsaturated station with respect to the epicenter, is used. Here, we present a Support Vector Regression algorithm which calculates Magnitude and Epicentral Distance using only five seconds of signal since P wave onset. This algorithm was trained with 36 records of historical earthquakes, where the input included regression parameters of an exponential function estimated by least squares, of the waveform envelope and the maximum value of the observed waveform for each component in a single station. A ten-fold Cross Validation was applied for a Normalized Polynomial Kernel obtaining the mean absolute error for different exponents and complexity parameters. The Magnitude could be estimated with 0.16 units of mean absolute error and the distance with an error of 7.5 km for distances within 60 to 120 km. This kind of algorithm is easy to implement in hardware and can be used directly in the field seismological sensor to make the broadcast of estimations of these values possible to generate fast decisions at seismological control centers, increasing the possibility of having an effective reaction.

Direct comparison of observed magnitude-redshift relations in complete galaxy samples with systematic predictions of alternative redshift-distance laws

International Nuclear Information System (INIS)

Segal, I.E.

1989-01-01

The directly observed average apparent magnitude (or in one case, angular diameter) as a function of redshift in each of a number of large complete galaxy samples is compared with the predictions of hypothetical redshift-distance power laws, as a systematic statistical question. Due account is taken of observational flux limits by an entirely objective and reproducible optimal statistical procedure, and no assumptions are made regarding the distribution of the galaxies in space. The laws considered are of the form z varies as r p , where r denotes the distance, for p = 1, 2 and 3. The comparative fits of the various redshift-distance laws are similar in all the samples. Overall, the cubic law fits better than the linear law, but each shows substantial systematic deviations from observation. The quadratic law fits extremely well except at high redshifts in some of the samples, where no power law fits closely and the correlation of apparent magnitude with redshift is small or negative. In all cases, the luminosity function required for theoretical prediction was estimated from the sample by the non-parametric procedure ROBUST, whose intrinsic neutrality as programmed was checked by comprehensive computer simulations. (author)

Epoxy Nanocomposites Containing Zeolitic Imidazolate Framework-8.

Science.gov (United States)

Liu, Cong; Mullins, Michael; Hawkins, Spencer; Kotaki, Masaya; Sue, Hung-Jue

2018-01-10

Zeolitic imidazole framework-8 (ZIF-8) is utilized as a functional filler and a curing agent in the preparation of epoxy nanocomposites. The imidazole group on the surface of the ZIF-8 initiates epoxy curing, resulting in covalent bonding between the ZIF-8 crystals and epoxy matrix. A substantial reduction in dielectric constant and increase in tensile modulus were observed. The implication of the present study for utilization of metal-organic framework to improve physical and mechanical properties of polymeric matrixes is discussed.

Evolution of glycaemia in the blood of mice in the presence or absence of imidazole; Evolution de la glycemie sanguine chez la souris protegee ou non par l'imidazole

Energy Technology Data Exchange (ETDEWEB)

Polverelli, M; Teoule, R [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1969-07-01

With respect to the radioprotective properties of the heterocyclic compound, imidazole, the authors followed the action of this product on blood sugar levels of mice X irradiated with a lethal dose. The main results of this work are: probably a hypo-glycemic action of the imidazole; an abolishment of the post-irradiation hyperglycemia by imidazole; an appreciably difference between male and female towards irradiation. (author) [French] Dans le cadre de l'etude des proprietes radioprotectrices de l'imidazole, nous nous sommes attaches a suivre l'action de ce produit sur le taux de glucose sanguin de souris irradiees a dose letale. Les principaux resultats de ce travail sont les suivants: l'action probablement hypoglycemiante de l'imidazole; en tant que radioprotecteur, cet heterocycle azote supprime l'hyperglycemie consecutive a l'irradiation; une difference assez sensible entre males et femelles vis-a-vis de l'irradiation. (auteur)

Very Fast Estimation of Epicentral Distance and Magnitude from a Single Three Component Seismic Station Using Machine Learning Techniques

Science.gov (United States)

Ochoa Gutierrez, L. H.; Niño Vasquez, L. F.; Vargas-Jimenez, C. A.

2012-12-01

To minimize adverse effects originated by high magnitude earthquakes, early warning has become a powerful tool to anticipate a seismic wave arrival to an specific location and lets to bring people and government agencies opportune information to initiate a fast response. To do this, a very fast and accurate characterization of the event must be done but this process is often made using seismograms recorded in at least 4 stations where processing time is usually greater than the wave travel time to the interest area, mainly in coarse networks. A faster process can be done if only one three component seismic station is used that is the closest unsaturated station respect to the epicenter. Here we present a Support Vector Regression algorithm which calculates Magnitude and Epicentral Distance using only 5 seconds of signal since P wave onset. This algorithm was trained with 36 records of historical earthquakes where the input were regression parameters of an exponential function estimated by least squares, corresponding to the waveform envelope and the maximum value of the observed waveform for each component in one single station. A 10 fold Cross Validation was applied for a Normalized Polynomial Kernel obtaining the mean absolute error for different exponents and complexity parameters. Magnitude could be estimated with 0.16 of mean absolute error and the distance with an error of 7.5 km for distances within 60 to 120 km. This kind of algorithm is easy to implement in hardware and can be used directly in the field station to make possible the broadcast of estimations of this values to generate fast decisions at seismological control centers, increasing the possibility to have an effective reactiontribute and Descriptors calculator for SVR model training and test

Inhibiting effects of imidazole on copper corrosion in 1 M HNO3 solution

International Nuclear Information System (INIS)

Lee, Woo-Jin

2003-01-01

The present work deals with the inhibiting effects of imidazole on the pure copper (Cu) corrosion in 1 M HNO 3 solution analysing potentiodynamic polarisation curves, potentiostatic anodic current transient, AC impedance spectra and X-ray photoelectron spectra (XPS). By adding imidazole to HNO 3 solution, the polarisation curves showed decrease in the corrosion current and the cathodic current, suggesting that imidazole acts as an effective cathodic inhibitor to Cu corrosion. From the measured anodic current transients, it is inferred that the protective Cu-imidazole complex film is simultaneously formed with the Cu oxide in the presence of imidazole during the early stage of the anodic polarisation. Analysis of the AC impedance spectra revealed that the values of the charge transfer resistance R ct obtained in imidazole-containing HNO 3 solution were greater than that value in imidazole-free one and at the same time steadily increased with immersion time to the constant value. Contrarily, the capacitance value was abruptly lowered from the double layer capacitance C dl to the complex film capacitance C cf in the progress of immersion time. Furthermore, the Warburg coefficient σ value for the ion diffusion through the complex film was observed to increase with immersion time. This means that the Cu(N-OH) complex film becomes thicker during immersion in the HNO 3 solution with imidazole through the inward growth of the N-rich outer layer to the O-rich inner layer, as well validated by XPS. Based upon the experimental results, it is suggested that the Cu corrosion in 1 M HNO 3 solution is efficiently inhibited with the addition of imidazole by retarding both the charge transfer on cathodic sites of the Cu surface in the early stage of immersion time and the subsequent ion diffusion through the steadily growing complex film

Etude structurale et vibrationnelle d'un nouveau composé complexe de cobalt: [Co(imidazole)4Cl]Cl.

Science.gov (United States)

Derbel, Amira; Mhiri, Tahar; Graia, Mohsen

2015-10-01

In the title complex, chlorido-tetra-kis-(1H-imidazole-κN (3))cobalt(II) chloride, [CoCl(C3H4N2)4]Cl, the Co(II) cation has a distorted square-pyramidal coordination environment. It is coordinated by four N atoms of four imidazole (Im) groups in the basal plane, and by a Cl atom in the apical position. It is isostructural with [Cu(Im)4Cl]Cl [Morzyk-Ociepa et al. (2012 ▸). J. Mol. Struct. 1028, 49-56] and [Cu(Im)4Br]Br [Hossaini Sadr et al. (2004 ▸). Acta Cryst. E60, m1324-m1326]. In the crystal, the [CoCl(C3H4N2)4](+) cations and Cl(-) anions are linked via N-H⋯Cl hydrogen bonds, forming layers parallel to (010). These layers are linked via C-H⋯Cl hydrogen bonds and C-H⋯π and π-π [inter-centroid distance = 3.794 (2) Å] inter-actions, forming a three-dimensional framework. The IR spectrum shows vibrational bands typical for imidazol groups. The monoclinic unit cell of the title compound emulates an ortho-rhom-bic cell as its β angle is close to 90°. The crystal is twinned, with the refined ratio of twin components being 0.569 (1):0.431 (1).

Transition-metal-free synthesis of N-(1-alkenyl)imidazoles by potassium phosphate-promoted addition reaction of alkynes to imidazoles.

Science.gov (United States)

Lu, Linhua; Yan, Hong; Liu, Defu; Rong, Guangwei; Mao, Jincheng

2014-01-01

The addition reaction of alkynes to N-heterocycles by simply heating in DMSO with potassium phosphate is reported. Good yields with high stereoselectivity could be achieved for a range of substrates. The scope is quite general for both amines and phenylacetylenes. In addition, internal alkynes and α-bromostyrene were also examined in this reaction. This process is efficient and useful for the synthesis of (Z)-N-(1-alkenyl)imidazoles and related Z products. Thus, the reaction is useful because of the importance of the imidazole scaffold. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evolutionary convergence in the biosyntheses of the imidazole moieties of histidine and purines.

Directory of Open Access Journals (Sweden)

Alberto Vázquez-Salazar

Full Text Available The imidazole group is an ubiquitous chemical motif present in several key types of biomolecules. It is a structural moiety of purines, and plays a central role in biological catalysis as part of the side-chain of histidine, the amino acid most frequently found in the catalytic site of enzymes. Histidine biosynthesis starts with both ATP and the pentose phosphoribosyl pyrophosphate (PRPP, which is also the precursor for the de novo synthesis of purines. These two anabolic pathways are also connected by the imidazole intermediate 5-aminoimidazole-4-carboxamide ribotide (AICAR, which is synthesized in both routes but used only in purine biosynthesis. Rather surprisingly, the imidazole moieties of histidine and purines are synthesized by different, non-homologous enzymes. As discussed here, this phenomenon can be understood as a case of functional molecular convergence.In this work, we analyze these polyphyletic processes and argue that the independent origin of the corresponding enzymes is best explained by the differences in the function of each of the molecules to which the imidazole moiety is attached. Since the imidazole present in histidine is a catalytic moiety, its chemical arrangement allows it to act as an acid or a base. On the contrary, the de novo biosynthesis of purines starts with an activated ribose and all the successive intermediates are ribotides, with the key β-glycosidic bondage joining the ribose and the imidazole moiety. This prevents purine ribonucleotides to exhibit any imidazole-dependent catalytic activity, and may have been the critical trait for the evolution of two separate imidazole-synthesizing-enzymes. We also suggest that, in evolutionary terms, the biosynthesis of purines predated that of histidine.As reviewed here, other biosynthetic routes for imidazole molecules are also found in extant metabolism, including the autocatalytic cyclization that occurs during the formation of creatinine from creatine phosphate

Evolution of glycaemia in the blood of mice in the presence or absence of imidazole; Evolution de la glycemie sanguine chez la souris protegee ou non par l'imidazole

Energy Technology Data Exchange (ETDEWEB)

Polverelli, M.; Teoule, R. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1969-07-01

With respect to the radioprotective properties of the heterocyclic compound, imidazole, the authors followed the action of this product on blood sugar levels of mice X irradiated with a lethal dose. The main results of this work are: probably a hypo-glycemic action of the imidazole; an abolishment of the post-irradiation hyperglycemia by imidazole; an appreciably difference between male and female towards irradiation. (author) [French] Dans le cadre de l'etude des proprietes radioprotectrices de l'imidazole, nous nous sommes attaches a suivre l'action de ce produit sur le taux de glucose sanguin de souris irradiees a dose letale. Les principaux resultats de ce travail sont les suivants: l'action probablement hypoglycemiante de l'imidazole; en tant que radioprotecteur, cet heterocycle azote supprime l'hyperglycemie consecutive a l'irradiation; une difference assez sensible entre males et femelles vis-a-vis de l'irradiation. (auteur)

Dual role of imidazole as activator/inhibitor of sweet almond (Prunus dulcis β-glucosidase

Directory of Open Access Journals (Sweden)

Sara Caramia

2017-07-01

Full Text Available The activity of Prunus dulcis (sweet almond β-glucosidase at the expense of p-nitrophenyl-β-d-glucopyranoside at pH 6 was determined, both under steady-state and pre-steady-state conditions. Using crude enzyme preparations, competitive inhibition by 1–5 mM imidazole was observed under both kinetic conditions tested. However, when imidazole was added to reaction mixtures at 0.125–0.250 mM, we detected a significant enzyme activation. To further inspect this effect exerted by imidazole, β-glucosidase was purified to homogeneity. Two enzyme isoforms were isolated, i.e. a full-length monomer, and a dimer containing a full-length and a truncated subunit. Dimeric β-glucosidase was found to perform much better than the monomeric enzyme, independently of the kinetic conditions used to assay enzyme activity. In addition, the sensitivity towards imidazole was found to differ between the two isoforms. While monomeric enzyme was indeed found to be relatively insensitive to imidazole, dimeric β-glucosidase was observed to be significantly activated by 0.125–0.250 mM imidazole under pre-steady-state conditions. Further, steady-state assays revealed that the addition of 0.125 mM imidazole to reaction mixtures increases the Km of dimeric enzyme from 2.3 to 6.7 mM. The activation of β-glucosidase dimer by imidazole is proposed to be exerted via a conformational transition poising the enzyme towards proficient catalysis.

Dual role of imidazole as activator/inhibitor of sweet almond (Prunus dulcis) β-glucosidase.

Science.gov (United States)

Caramia, Sara; Gatius, Angela Gala Morena; Dal Piaz, Fabrizio; Gaja, Denis; Hochkoeppler, Alejandro

2017-07-01

The activity of Prunus dulcis (sweet almond) β-glucosidase at the expense of p -nitrophenyl-β-d-glucopyranoside at pH 6 was determined, both under steady-state and pre-steady-state conditions. Using crude enzyme preparations, competitive inhibition by 1-5 mM imidazole was observed under both kinetic conditions tested. However, when imidazole was added to reaction mixtures at 0.125-0.250 mM, we detected a significant enzyme activation. To further inspect this effect exerted by imidazole, β-glucosidase was purified to homogeneity. Two enzyme isoforms were isolated, i.e. a full-length monomer, and a dimer containing a full-length and a truncated subunit. Dimeric β-glucosidase was found to perform much better than the monomeric enzyme, independently of the kinetic conditions used to assay enzyme activity. In addition, the sensitivity towards imidazole was found to differ between the two isoforms. While monomeric enzyme was indeed found to be relatively insensitive to imidazole, dimeric β-glucosidase was observed to be significantly activated by 0.125-0.250 mM imidazole under pre-steady-state conditions. Further, steady-state assays revealed that the addition of 0.125 mM imidazole to reaction mixtures increases the K m of dimeric enzyme from 2.3 to 6.7 mM. The activation of β-glucosidase dimer by imidazole is proposed to be exerted via a conformational transition poising the enzyme towards proficient catalysis.

Fourier Magnitude-Based Privacy-Preserving Clustering on Time-Series Data

Science.gov (United States)

Kim, Hea-Suk; Moon, Yang-Sae

Privacy-preserving clustering (PPC in short) is important in publishing sensitive time-series data. Previous PPC solutions, however, have a problem of not preserving distance orders or incurring privacy breach. To solve this problem, we propose a new PPC approach that exploits Fourier magnitudes of time-series. Our magnitude-based method does not cause privacy breach even though its techniques or related parameters are publicly revealed. Using magnitudes only, however, incurs the distance order problem, and we thus present magnitude selection strategies to preserve as many Euclidean distance orders as possible. Through extensive experiments, we showcase the superiority of our magnitude-based approach.

On the mechanism of action of ribonucleases: dinucleotide cleavage catalyzed by imidazole and Zn2+.

OpenAIRE

Breslow, R; Huang, D L; Anslyn, E

1989-01-01

Cyclization/cleavage of the 2-(p-nitrophenyl) phosphate ester of propylene glycol is catalyzed by imidazole and, much more effectively, by Zn2+ with imidazole. In the latter case, the mechanism involves simultaneous Lewis acid/base catalysis. Similar Zn2+ and imidazole catalysis of cyclization/cleavage is seen with the dinucleotide 3',5'-UpU (uridylyluridine). Again, the zinc system is much more effective than is catalysis by imidazole alone, and in this case simultaneous Lewis acid/base cata...

Coordination compounds of metals with imidazoles and benzimidazoles

International Nuclear Information System (INIS)

Novikova, G.A.; Molodkin, A.K.; Kukalenko, S.S.

1988-01-01

Methods of preparation, composition and structure of UO 2 2+ , Th 4+ , Mo 3+ , Cd 2+ , Ln 3+ metal ion complexes with imidazoles and benzimidazoles are considered in reviews of native and foreign literature of up to 1985. Complexes are customarily prepared by direct interaction of ligands with inorganic salts in different organic solvents. Complex composition is defined by the nature of complexing metal and inorganic salt anion, ligand volume and basicity, as well as solvent characteristics. Effect of R substituent in imidazole and benzimidazole side chain on composition of coordination compounds is considered

Characterization for coating processes of imidazole powders using an ultrasonic atomizer

Energy Technology Data Exchange (ETDEWEB)

Lee, Jun Sik; Kim, Jun Ki [Korea Institute of Industrial Technology, Incheon (Korea, Republic of); Kim, Mok Soon [Inha University, Incheon (Korea, Republic of); Lee, Jong Hyun [Seoul National University, Seoul (Korea, Republic of)

2010-01-15

Imidazole-curing accelerator powders were coated with stearic acid to increase the pot life of anisotropic conductive adhesive (ACA) formulations. To accomplish an efficient coating process, the coating was tested using an ultrasonic atomizer after mixing imidazole powders with a molten coating agent. Design of experiments analysis was organized to elucidate the effect of process parameters and to determine the most crucial parameter. The final formulation incorporating well-processed imidazole loaded powders indicated longer pot life, higher shear strength, and excellent highly accelerated stress test (HAST) reliability. Results show that the coating process using an ultrasonic atomizer is effective in increasing the pot life of ACA formulations

Crystal structure of tetraaqua[2-(pyridin-2-yl-1H-imidazole-κ2N2,N3]iron(II sulfate

Directory of Open Access Journals (Sweden)

Zouaoui Setifi

2015-04-01

Full Text Available In the title compound, [Fe(C8H7N3(H2O4]SO4, the central FeII ion is octahedrally coordinated by two N atoms from the bidentate 2-(pyridin-2-yl-1H-imidazole ligand and by four O atoms of the aqua ligands. The largest deviation from the ideal octahedral geometry is reflected by the small N—Fe—N bite angle of 76.0 (1°. The Fe—N coordination bonds have markedly different lengths [2.1361 (17 and 2.243 (2 Å], with the shorter one to the pyrimidine N atom. The four Fe—O coordination bond lengths vary from 2.1191 (18 to 2.1340 (17 Å. In the crystal, the cations and anions are arranged by means of medium-strength O—H...O hydrogen bonds into layers parallel to the ab plane. Neighbouring layers further interconnect by N—H...O hydrogen bonds involving the imidazole fragment as donor group to one sulfate O atom as an acceptor. The resulting three-dimensional network is consolidated by C—H...O, C—H...π and π–π interactions.

Some thiocyanato complexes of cadmium(II) with substituted pyridines and imidazoles

Energy Technology Data Exchange (ETDEWEB)

Mishra, B P; Ramana Rao, D V [Regional Engineering Coll., Rourkela (India). Dept. of Chemistry

1979-05-01

The complexes formed by cadmium(II) thiocyanate with 3-acetyl-, 3-bromo-, 3-methyl-, 4-acetyl-, 4-cyano-, 4-benzoyl pyridines, isoquinoline, 3,5-lutidine and imidazole, 2-methyl imidazole, 2-methyl benzimidazoles have been characterised through elemental analysis and molar conductance data. On the basis of infra-red spectroscopic studies, probable structures are discussed.

Representation of numerical magnitude in math-anxious individuals.

Science.gov (United States)

Colomé, Àngels

2018-01-01

Larger distance effects in high math-anxious individuals (HMA) performing comparison tasks have previously been interpreted as indicating less precise magnitude representation in this population. A recent study by Dietrich, Huber, Moeller, and Klein limited the effects of math anxiety to symbolic comparison, in which they found larger distance effects for HMA, despite equivalent size effects. However, the question of whether distance effects in symbolic comparison reflect the properties of the magnitude representation or decisional processes is currently under debate. This study was designed to further explore the relation between math anxiety and magnitude representation through three different tasks. HMA and low math-anxious individuals (LMA) performed a non-symbolic comparison, in which no group differences were found. Furthermore, we did not replicate previous findings in an Arabic digit comparison, in which HMA individuals showed equivalent distance effects to their LMA peers. Lastly, there were no group differences in a counting Stroop task. Altogether, an explanation of math anxiety differences in terms of less precise magnitude representation is not supported.

cobaloxime by imidazoles and amino acids

Indian Academy of Sciences (India)

Unknown

to replicate them in experimental model systems with ... Axial ligation kinetics was monitored .... A trans influence study in propyl (aquo)cobaloxime by imidazoles and amino acids. 307 .... unfilled π* anti-bonding orbitals through dπ–pπ back-.

An analysis of Greek seismicity based on Non Extensive Statistical Physics: The interdependence of magnitude, interevent time and interevent distance.

Science.gov (United States)

Efstathiou, Angeliki; Tzanis, Andreas; Vallianatos, Filippos

2014-05-01

The context of Non Extensive Statistical Physics (NESP) has recently been suggested to comprise an appropriate tool for the analysis of complex dynamic systems with scale invariance, long-range interactions, long-range memory and systems that evolve in a fractal-like space-time. This is because the active tectonic grain is thought to comprise a (self-organizing) complex system; therefore, its expression (seismicity) should be manifested in the temporal and spatial statistics of energy release rates. In addition to energy release rates expressed by the magnitude M, measures of the temporal and spatial interactions are the time (Δt) and hypocentral distance (Δd) between consecutive events. Recent work indicated that if the distributions of M, Δt and Δd are independent so that the joint probability p(M,Δt,Δd) factorizes into the probabilities of M, Δt and Δd, i.e. p(M,Δt,Δd)= p(M)p(Δt)p(Δd), then the frequency of earthquake occurrence is multiply related, not only to magnitude as the celebrated Gutenberg - Richter law predicts, but also to interevent time and distance by means of well-defined power-laws consistent with NESP. The present work applies these concepts to investigate the self-organization and temporal/spatial dynamics of seismicity in Greece and western Turkey, for the period 1964-2011. The analysis was based on the ISC earthquake catalogue which is homogenous by construction with consistently determined hypocenters and magnitude. The presentation focuses on the analysis of bivariate Frequency-Magnitude-Time distributions, while using the interevent distances as spatial constraints (or spatial filters) for studying the spatial dependence of the energy and time dynamics of the seismicity. It is demonstrated that the frequency of earthquake occurrence is multiply related to the magnitude and the interevent time by means of well-defined multi-dimensional power-laws consistent with NESP and has attributes of universality,as its holds for a broad

Bis[μ-1,2-bis(1H-imidazol-1-ylmethylbenzene-κ2N3:N3′]disilver(I 3-carboxylato-4-hydroxybenzenesulfonate methanol solvate trihydrate

Directory of Open Access Journals (Sweden)

Hong-Mei Sun

2009-09-01

Full Text Available In the title compound, [Ag2(C14H14N42](C7H4O6S·CH3OH·3H2O, the complex dication has a binuclear structure in which each AgI ion is two-coordinated in a slightly distorted linear coordination geometry. The two AgI atoms are bridged by two 1,2-bis[(1H-imidazol-1-ylmethyl]benzene (IBI ligands, forming a 22-membered ring. In the dication, π–π interactions are observed between the imidazole rings with centroid–centroid distances of 3.472 (3 and 3.636 (3 Å. In the crystal, the uncoordinated water molecules, anions and methanol solvent molecules are linked into chains along the b axis by O—H...O hydrogen bonds. In addition, π–π interactions are observed between the benzene rings of the IBI ligands, with a centroid–centroid distance of 3.776 (2 Å. The sulfonate group is disordered over two orientations with occupancies of 0.676 (12 and 0.324 (12.

Imidazole, a New Tunable Reagent for Producing Nanocellulose, Part I: Xylan-Coated CNCs and CNFs

Directory of Open Access Journals (Sweden)

Jia Mao

2017-09-01

Full Text Available Imidazole is reported to be an effective reactant for the production of nanocellulose from hardwood pulp. The morphologies and surface properties of the nanocellulose can be simply tailored according to the water content in the imidazole system: with pure imidazole, cellulose nanofibrils (CNFs in a yield of 10 wt % can be produced. With 25 wt % of water in imidazole, cellulose nanocrystals (CNCs are obtained in 20 wt % yield. Both nanocelluloses exhibit crystallinity indices in the order of 70%. Interestingly, they retain the original xylan from the pulp with ca. 9–10 wt % of residual xylan content.

High-Resolution Infrared Spectroscopy of Imidazole Clusters in Helium Droplets Using Quantum Cascade Lasers

Science.gov (United States)

Mani, Devendra; Can, Cihad; Pal, Nitish; Schwaab, Gerhard; Havenith, Martina

2017-06-01

Imidazole ring is a part of many biologically important molecules and drugs. Imidazole monomer, dimer and its complexes with water have earlier been studied using infrared spectroscopy in helium droplets^{1,2} and molecular beams^{3}. These studies were focussed on the N-H and O-H stretch regions, covering the spectral region of 3200-3800 \\wn. We have extended the studies on imidazole clusters into the ring vibration region. The imidazole clusters were isolated in helium droplets and were probed using a combination of infrared spectroscopy and mass spectrometry. The spectra in the region of 1000-1100 \\wn and 1300-1460 \\wn were recorded using quantum cascade lasers. Some of the observed bands could be assigned to imidazole monomer and higher order imidazole clusters, using pickup curve analysis and ab initio calculations. Work is still in progress. The results will be discussed in detail in the talk. References: 1) M.Y. Choi and R.E. Miller, J. Phys. Chem. A, 110, 9344 (2006). 2) M.Y. Choi and R.E. Miller, Chem. Phys. Lett., 477, 276 (2009). 3) J. Zischang, J. J. Lee and M. Suhm, J. Chem. Phys., 135, 061102 (2011). Note: This work was supported by the Cluster of Excellence RESOLV (Ruhr-Universitat EXC1069) funded by the Deutsche Forschungsgemeinschaft.

Reactivity of tris(acetylacetonato) iron(III) with tridentate [ONO] donor Schiff base as an access to newer mixed-ligand iron(III) complexes

Science.gov (United States)

Bhattacharjee, Chira R.; Goswami, Pankaj; Pramanik, Harun A. R.; Paul, Pradip C.; Mondal, Paritosh

2011-05-01

Two new mixed-ligand iron(III) complexes, [Fe(L n)(acac)(C 2H 5OH)] incorporating coordinated ethanol from the reaction solvent were accessed from the reaction of [Fe(acac) 3] with [ONO] donor dibasic tridentate unsymmetrical Schiff base ligands derived from condensation of 2-hydroxy-1-napthaldehyde with 2-aminophenol (H 2L 1) or 2-aminobenzoic acid (H 2L 2). The thermal study (TGA-DTA) provided evidence for weakly bound ethanol which is readily substituted by neutral N-donor molecule imidazole, benzimidazole or pyridine to produce an array of newer complexes, [Fe(L n)(acac)X] ( n = 1, 2; X = Im, Bim, Py). The compounds were characterized by elemental analyses, FT-IR, UV-vis, solution electrical conductivity, FAB mass, 1H and 13C NMR spectroscopy. Room temperature magnetic susceptibility measurements ( μeff ˜ 5.8 B.M.) are consistent with spin-free octahedral iron(III) complexes. Cyclic voltammetry of ethanol complexes revealed a quasi-reversible one electron redox response (Δ Ep > 100 mV) for the Fe(III)/Fe(II) couple. Low half wave redox potential ( E1/2) values suggested easy redox susceptibility. The ground state geometries of the ethanol and imidazole complexes have been ascertained to be distorted octahedral by density functional theory using DMol3 program at BLYP/DNP level.

Multifunctional switches based on bis-imidazole derivative

Indian Academy of Sciences (India)

Administrator

photonic, chemical, electrochemical, or magnetic stimuli and generate ... that upon oxidation with potassium ferricyanide in ethanolic ... cooled to room temperature and filtered to remove ... Recrystaliztion from ethanol afforded the imidazole 3.

Synthesis of Trisubstituted Imidazoles Using Lewis and Bronsted Acid Catalysts

OpenAIRE

Hekmatshoar, Rahim; HEKMATSHOAR, Rahim; JAHANBAKHSHI, Hajar; MOUSAVIZADEH, Farnoosh; RAHNAMAFAR, Reyhane

2010-01-01

An efficient and one-pot method for the preparation of trisubstituted imidazoles by condensation of benzil, different aldehydes and ammonium acetate in the presence of  a catalytic amount of NiSO4.7H2O or H3BO3 under different conditions is reported.                    Key Words: Trisubstituted imidazoles, Multi-component &a...

Imidazole and Triazole Coordination Chemistry for Antifouling Coatings

Directory of Open Access Journals (Sweden)

Markus Andersson Trojer

2013-01-01

Full Text Available Fouling of marine organisms on the hulls of ships is a severe problem for the shipping industry. Many antifouling agents are based on five-membered nitrogen heterocyclic compounds, in particular imidazoles and triazoles. Moreover, imidazole and triazoles are strong ligands for Cu2+ and Cu+, which are both potent antifouling agents. In this review, we summarize a decade of work within our groups concerning imidazole and triazole coordination chemistry for antifouling applications with a particular focus on the very potent antifouling agent medetomidine. The entry starts by providing a detailed theoretical description of the azole-metal coordination chemistry. Some attention will be given to ways to functionalize polymers with azole ligands. Then, the effect of metal coordination in azole-containing polymers with respect to material properties will be discussed. Our work concerning the controlled release of antifouling agents, in particular medetomidine, using azole coordination chemistry will be reviewed. Finally, an outlook will be given describing the potential for tailoring the azole ligand chemistry in polymers with respect to Cu2+ adsorption and Cu2+→Cu+ reduction for antifouling coatings without added biocides.

2-(1H-Imidazol-1-yl)-3-isopropyl-1-benzothieno[3,2-d]pyrimidin-4(3H)-one

OpenAIRE

Xu, Sheng-Zhen

2007-01-01

In the title compound, C16H14N4OS, the three fused rings of the benzothieno[3,2-d]pyrimidinone unit are essentially coplanar, the maximum deviation from the mean plane being 0.067 (3) Å. The dihedral angle between the mean plane of the fused rings and the imidazole ring is 72.00 (3)°. Offset π–π stacking interactions involving the fused rings are effective in the stabilization of the crystal structure. The centroid–centroid distances between t...

Efficacy of iron fortification compared to iron supplementation among Vietamese schoolchildren

NARCIS (Netherlands)

Le, Huong T.; Brouwer, I.D.; Burema, J.; NGuyen, K.C.; Kok, F.J.

2006-01-01

The effect of iron fortification is generally assumed to be less than iron supplementation; however, the magnitude of difference in effects is not known. The present study aims to compare the efficacy of these two strategies on anaemia and iron status. After screening on low Hb, 425 anaemic children

Spectroscopic study of 2-, 4- and 5-substituents on p Ka values of imidazole heterocycles prone to intramolecular proton-electrons transfer

Science.gov (United States)

Eseola, Abiodun O.; Obi-Egbedi, Nelson O.

2010-02-01

New 2-(1H-imidazol-2-yl)phenols ( L1Et- L8tBuPt) bearing a phenolic proton in the vicinity of the imidazole base were prepared and characterized. Experimental studies of the dependence of their protonation/deprotonation equilibrium on substituent identities and intramolecular hydrogen bonding tendencies were carried out using electronic absorption spectroscopy at varying pH values. In order to make comparison, 2-(anthracen-10-yl)-4,5-diphenyl-1H-imidazole ( L9Anthr) bearing no phenolic proton and 4,5-diphenyl-2-(4,5-diphenyl-1H-imidazol-2-yl)-1H-imidazole ( L10BisIm) bearing two symmetrical imidazole base fragments were also prepared and experimentally investigated. DFT calculations were carried out to study frontier orbitals of the investigated molecules. While electron-releasing substituents produced increase in protonation-deprotonation p Kas for the hydroxyl group, values for the imidazole base were mainly affected by polarization of the imidazole ring aromaticity across the 2-imidazole carbon and the 4,5-imidazole carbons axis of the imidazole ring. It was concluded that electron-releasing substituents on the phenol ring and/or electron-withdrawing substituents on 4,5-imidazole carbons negatively affects donor strengths/coordination chemistries of 2-(1H-imidazol-2-yl)phenols, and vice versa. Change of substituents on the phenol ring significantly altered the donor strength of the imidazole base. The understanding of p Ka variation on account of electronic effects of substituents in this work should aid the understanding of biochemical properties and substituent environments of imidazole-containing biomacromolecules.

Phase transition behavior of novel pH-sensitive polyaspartamide derivatives grafted with 1-(3-aminopropyl)imidazole.

Science.gov (United States)

Seo, Kwangwon; Kim, Dukjoon

2006-09-15

New pH-sensitive polyaspartamide derivatives were synthesized by grafting 1-(3-aminopropyl)imidazole and/or O-(2-aminoethyl)-O'-methylpoly(ethylene glycol) 5000 on polysuccinimide for application in intracellular drug delivery systems. The DS of 1-(3-aminopropyl)imidazole was adjusted by the feed molar ratio, and the structure of the prepared polymer was confirmed using FT-IR and 1H NMR spectroscopy. Their pH-sensitive properties were characterized by light transmittance measurements, and the particle size and its distribution were investigated by dynamic light scattering measurements at varying pH values. The pH-sensitive phase transition was clearly observed in polymer solutions with a high substitution of 1-(3-aminopropyl)imidazole. The prepared polymers showed a high buffering capacity between pH 5 and 7, and this increased with the DS of 1-(3-aminopropyl)imidazole. The pH dependence of the aggregation and de-aggregation behavior was examined using a fluorescence spectrometer. For MPEG/imidazole-g-polyaspartamides with a DS of 1-(3-aminopropyl)imidazole over 82%, self aggregates associated with the hydrophobic interactions of the unprotonated imidazole groups were observed at pH values above 7, and their mean size was over 200 nm, while the aggregates of polymers were dissociated at pH values below 7 by the protonation of imidazole groups. These pH-sensitive polyaspartamide derivatives are potential basic candidates for intracellular drug delivery carriers triggered by small pH changes.

1-[(3-Aryloxy-3-aryl)propyl]-1H-imidazoles, new imidazoles with potent activity against Candida albicans and dermatophytes. Synthesis, structure-activity relationship, and molecular modeling studies.

Science.gov (United States)

La Regina, Giuseppe; D'Auria, Felicia Diodata; Tafi, Andrea; Piscitelli, Francesco; Olla, Stefania; Caporuscio, Fabiana; Nencioni, Lucia; Cirilli, Roberto; La Torre, Francesco; De Melo, Nadja Rodrigues; Kelly, Steven L; Lamb, David C; Artico, Marino; Botta, Maurizio; Palamara, Anna Teresa; Silvestri, Romano

2008-07-10

New 1-[(3-aryloxy-3-aryl)propyl]-1 H-imidazoles were synthesized and evaluated against Candida albicans and dermatophytes in order to develop structure-activity relationships (SARs). Against C. albicans the new imidazoles showed minimal inhibitory concentrations (MICs) comparable to those of ketoconazole, miconazole, and econazole, and were more potent than fluconazole. Several derivatives ( 10, 12, 14, 18- 20, 24, 28, 29, 30, and 34) turned out to be potent inhibitors of C. albicans strains resistant to fluconazole, with MIC values less than 10 microg/mL. Against dermatophytes strains, compounds 20, 25, and 33 (MIC imidazoles 10- 44 were rationalized with reasonable accuracy by a previously developed quantitative pharmacophore for antifungal agents.

Synthesis and properties of imidazole-grafted hybrid inorganic-organic polymer membranes

International Nuclear Information System (INIS)

Li Siwen; Zhou Zhen; Liu Meilin; Li Wen; Ukai, Junzo; Hase, Kohei; Nakanishi, Masatsugu

2006-01-01

Imidazole rings were grafted on alkoxysilane with a simple nucleophilic substitute reaction to form hybrid inorganic-organic polymers with imidazole rings. Proton exchange membranes (PEM) based on these hybrid inorganic-organic polymers and H 3 PO 4 exhibit high proton conductivity and high thermal stability in an atmosphere of low relative humidity. The grafted imidazole rings improved the proton conductivity of the membranes in the high temperature range. It is found that the proton conductivities increase with H 3 PO 4 content and temperature, reaching 3.2 x 10 -3 S/cm at 110 deg. C in a dry atmosphere for a membrane with 1 mole of imidazole ring and 7 moles of H 3 PO 4 . The proton conductivity increases with relative humidity (RH) as well, reaching 4.3 x 10 -2 S/cm at 110 deg. C when the RH is increased to about 20%. Thermogravimetric analysis (TGA) indicates that these membranes are thermally stable up to 250 deg. C in dry air, implying that they have a good potential to be used as the membranes for high-temperature PEM fuel cells

The Development of the Mental Representations of the Magnitude of Fractions

Science.gov (United States)

Gabriel, Florence C.; Szucs, Denes; Content, Alain

2013-01-01

We investigated the development of the mental representation of the magnitude of fractions during the initial stages of fraction learning in grade 5, 6 and 7 children as well as in adults. We examined the activation of global fraction magnitude in a numerical comparison task and a matching task. There were global distance effects in the comparison task, but not in the matching task. This suggests that the activation of the global magnitude representation of fractions is not automatic in all tasks involving magnitude judgments. The slope of the global distance effect increased during early fraction learning and declined by adulthood, demonstrating that the development of the fraction global distance effect differs from that of the integer distance effect. PMID:24236169

Evolution of glycaemia in the blood of mice in the presence or absence of imidazole

International Nuclear Information System (INIS)

Polverelli, M.; Teoule, R.

1969-01-01

With respect to the radioprotective properties of the heterocyclic compound, imidazole, the authors followed the action of this product on blood sugar levels of mice X irradiated with a lethal dose. The main results of this work are: probably a hypo-glycemic action of the imidazole; an abolishment of the post-irradiation hyperglycemia by imidazole; an appreciably difference between male and female towards irradiation. (author) [fr

Proximal tibia volumetric bone mineral density is correlated to the magnitude of local acceleration in male long-distance runners

OpenAIRE

Dériaz, Olivier; Najafi, Bijan; Ballabeni, Pierluigi; Crettenand, Antoinette; Gobelet, Charles; Aminian, Kamiar; Rizzoli, René; Gremion, Gerald

2010-01-01

The beneficial effect of physical exercise on bone mineral density (BMD) is at least partly explained by the forces exerted directly on the bones. Male runners present generally higher BMD than sedentary individuals. We postulated that the proximal tibia BMD is related to the running distance, as well as to the magnitude of the shocks (while running) in male runners. A prospective study (three yearly measurements) included 81 healthy male subjects: 16 sedentary lean subjects, and 3 groups of ...

Phosphoric acid doped polysulfone membranes with aminopyridine pendant groups and imidazole cross-links

DEFF Research Database (Denmark)

Hink, Steffen; Elsøe, Katrine; Cleemann, Lars Nilausen

2015-01-01

Udel polysulfone based membranes with 4-aminopyridine pendant groups and cross-linking imidazole units are synthesized in a simple two step reaction. The ratio of 4-aminopyridine and imidazole is varied and the materials are extensively characterized. The average phosphoric acid uptake (in 85 wt%...

A Study of the Radioprotective Activity of the Imidazole Nucleus and Some of Its Derivatives; Etude de l'activite radioprotectrice du noyau imidazole et de quelquesuns de ses derives

Energy Technology Data Exchange (ETDEWEB)

Rinaldi, R; Bernard, Y [Commissariat a l' Energie Atomique. Centre d' Etudes Nucleaires, 38 - Grenoble (France)

1962-07-01

A study was made of the radioprotective properties of 8 compounds derived from imidazole. The effectiveness of the compounds was tested in mice exposed to a lethal dose of x radiation. Results showed that imidazole afforded protection to about 85% of the animals. Little protection was afforded by imidazoline and thione-imidazoline compounds in spite of the existence of a free sulfhydryl group in these compounds. (authors) [French] Cette etude a ete consacree a la determination des proprietes radioprotectrices eventuelles de huit composes derives de l'imidazole. Ces substances ont ete, soit synthetisees, soit obtenues dans le commerce. Leur efficacite a ete mise en evidence par le pourcentage de survie obtenu chez des souris soumises a une dose mortelle de rayons X. Les resultats ont fait apparaitre: - l'activite remarquable de l'imidazole qui protege environ 85 pour cent des animaux; - la protection faible ou nulle obtenue avec les imidazolinones et les thione-imidazolines, malgre la presence dans la molecule de ces dernieres d'un groupement sulfhydrile libre. (auteurs)

Thermodynamic study of phase transitions of imidazoles and 1-methylimidazoles

Energy Technology Data Exchange (ETDEWEB)

Almeida, Ana R.R.P., E-mail: ana.figueira@fc.up.pt [Centro de Investigacao em Quimica, Departamento de Quimica e Bioquimica, Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal); Monte, Manuel J.S., E-mail: mjmonte@fc.up.pt [Centro de Investigacao em Quimica, Departamento de Quimica e Bioquimica, Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal)

2012-01-15

Highlights: > Sublimation vapor pressures of imidazole, N-methylimidazole and four derivatives were measured. > Liquid vapor pressures were also measured for four of the compounds studied. > Vapor pressure results enabled determination of sublimation, vaporization, and fusion enthalpy. > From enthalpies of sublimation, enthalpies of intermolecular N-H...N bonds were estimated. - Abstract: The vapor pressures of imidazole, N-methylimidazole and of their dichloro and dicyano substituted compounds were measured at different temperatures, in the crystalline phase for two of them, and in crystalline and liquid phases for the other four. From these measurements, enthalpies and standard entropies of sublimation and vaporization were derived. The results allowed the determination of the triple points (p, T) coordinates of the four compounds studied in both condensed phases as well as the calculation of their enthalpy of fusion. Enthalpies and temperatures of fusion were also determined using d.s.c. The experimental results enabled the estimation of the enthalpy of the intermolecular N-H...N bonds in the imidazoles studied.

Synthesis and potential cytotoxic activity of some new benzoxazoles, imidazoles, benzimidazoles and tetrazoles.

Science.gov (United States)

Arulmurugan, Subramaniyan; Kavitha, Helen P

2013-06-01

2 The present work deals with the synthesis of some novel heterocyclic compounds such as benzoxazoles , 7, 13 and 19, imidazoles 3, 8, 14 and 20, benzimidazoles 4, 9, 15 and 21, and tetrazoles 10, 16, and 22. The synthesized compounds were characterized by IR, 1H NMR, mass spectrometry and elemental analysis. The compounds were evaluated for cytotoxicity against human cancer cell lines such as MCF-7 (breast cancer) and HT-29 (colon cancer) by the MTT assay method. Among the tested compounds, 4,4'-sulfonylbis(N-(2-(1H-benzo[d]imidazol- -2-yl)ethyl)aniline (9), N-bis(2-(benzo[d]oxazol-2-yl)-ethyl)- 6-phenyl-1,3,5-triazine-2,4-diamine (13), N-bis(2-(1H-benzo[ d]imidazol-2-yl)ethyl)-6-phenyl-1,3,5-triazine-2,4-diamine (15) and N-tris(2-1H-benzo[d]imidazol-2-yl)ethyl)- 1,3,5-triazine-2,4,6-triamine (21) showed potent cytotoxicity.

An electrophysiological investigation of non-symbolic magnitude processing: numerical distance effects in children with and without mathematical learning disabilities.

Science.gov (United States)

Heine, Angela; Wissmann, Jacqueline; Tamm, Sascha; De Smedt, Bert; Schneider, Michael; Stern, Elsbeth; Verschaffel, Lieven; Jacobs, Arthur M

2013-09-01

The aim of the present study was to probe electrophysiological effects of non-symbolic numerical processing in 20 children with mathematical learning disabilities (mean age = 99.2 months) compared to a group of 20 typically developing matched controls (mean age = 98.4 months). EEG data were obtained while children were tested with a standard non-symbolic numerical comparison paradigm that allowed us to investigate the effects of numerical distance manipulations for different set sizes, i.e., the classical subitizing, counting and estimation ranges. Effects of numerical distance manipulations on event-related potential (ERP) amplitudes as well as activation patterns of underlying current sources were analyzed. In typically developing children, the amplitudes of a late parietal positive-going ERP component showed systematic numerical distance effects that did not depend on set size. For the group of children with mathematical learning disabilities, ERP distance effects were found only for stimuli within the subitizing range. Current source density analysis of distance-related group effects suggested that areas in right inferior parietal regions are involved in the generation of the parietal ERP amplitude differences. Our results suggest that right inferior parietal regions are recruited differentially by controls compared to children with mathematical learning disabilities in response to non-symbolic numerical magnitude processing tasks, but only for stimuli with set sizes that exceed the subitizing range. Copyright © 2012 Elsevier Ltd. All rights reserved.

Investigation of cobalt porphyrin doped polymer membrane films for the optical sensing of imidazole and its derivatives

Directory of Open Access Journals (Sweden)

Yueyang Tan

2015-03-01

Full Text Available A cobalt(II porphyrin was successfully incorporated into polymer membranes for the optical sensing of imidazole and its derivatives. This research has led to a better understanding of the behavior of Co(II porphyrin in solution and in polymeric membranes. In aprotic dichloromethane (DCM, the Co(II tetraphenylporphyrin (CoTPP and Co(II octaethylporphyrin (CoOEP show a sensitive response to imidazole due to the strong ligation of the N-3 on the imidazole ring to the Co(II center, which induces an absorbance change to the Soret band. However, when doped in polymeric films, only the CoTPP exhibits moderate sensitivity towards aqueous imidazole, histamine and histidine. This weakened coordination ability of CoTPP towards imidazole in the polymer films may be due to the coordination of the plasticizer, the impurities from the THF and polymer matrix at the Co(II center. The selectivity of the polymer films towards imidazole over common anions is high. Lifetime of the cobalt(II porphyrin incorporated polymer film was relatively short.

Novel synthesis of 4(5)-monosubstituted imidazoles via cycloaddition of tosylmethyl isocyanide to aldimines

NARCIS (Netherlands)

ten Have, Ronald; Huisman, M; Meetsma, A; van Leusen, A.M.

1997-01-01

4(5)-Monosubstituted imidazoles (9) have been prepared via base-induced cycloaddition of tosylmethyl isocyanide (TosMIC) to N-(dimethylsulfamoyl)aldimines (2) or N-tosylaldimines (3). In the first case, N-(dimethylsulfamoyl)imidazoles 8 are the initial reaction products, from which the

Thermodynamic study of phase transitions of imidazoles and 1-methylimidazoles

International Nuclear Information System (INIS)

Almeida, Ana R.R.P.; Monte, Manuel J.S.

2012-01-01

Highlights: → Sublimation vapor pressures of imidazole, N-methylimidazole and four derivatives were measured. → Liquid vapor pressures were also measured for four of the compounds studied. → Vapor pressure results enabled determination of sublimation, vaporization, and fusion enthalpy. → From enthalpies of sublimation, enthalpies of intermolecular N-H...N bonds were estimated. - Abstract: The vapor pressures of imidazole, N-methylimidazole and of their dichloro and dicyano substituted compounds were measured at different temperatures, in the crystalline phase for two of them, and in crystalline and liquid phases for the other four. From these measurements, enthalpies and standard entropies of sublimation and vaporization were derived. The results allowed the determination of the triple points (p, T) coordinates of the four compounds studied in both condensed phases as well as the calculation of their enthalpy of fusion. Enthalpies and temperatures of fusion were also determined using d.s.c. The experimental results enabled the estimation of the enthalpy of the intermolecular N-H...N bonds in the imidazoles studied.

Imidazoles and benzimidazoles as tubulin-modulators for anti-cancer therapy.

Science.gov (United States)

Torres, Fernando C; García-Rubiño, M Eugenia; Lozano-López, César; Kawano, Daniel F; Eifler-Lima, Vera L; von Poser, Gilsane L; Campos, Joaquín M

2015-01-01

Imidazoles and benzimidazoles are privileged heterocyclic bioactive compounds used with success in the clinical practice of innumerous diseases. Although there are many advancements in cancer therapy, microtubules remain as one of the few macromolecular targets validated for planning active anti-cancer compounds, and the design of drugs that modulate microtubule dynamics in unknown sites of tubulin is one of the goals of the medicinal chemistry. The discussion of the role of new and commercially available imidazole and benzimidazole derivatives as tubulin modulators is scattered throughout scientific literature, and indicates that these compounds have a tubulin modulation mechanism different from that of tubulin modulators clinically available, such as paclitaxel, docetaxel, vincristine and vinblastine. In fact, recent literature indicates that these derivatives inhibit microtubule formation binding to the colchicine site, present good pharmacokinetic properties and are capable of overcoming multidrug resistance in many cell lines. The understanding of the mechanisms involved in the imidazoles/benzimidazoles modulation of microtubule dynamics is very important to develop new strategies to overcome the resistance to anti-cancer drugs and to discover new biomarkers and targets for cancer chemotherapy.

Monomeric Yeast Frataxin is an Iron-Binding Protein

International Nuclear Information System (INIS)

Cook, J.; Bencze, K.; Jankovic, A.; Crater, A.; Busch, C.; Bradley, P.; Stemmler, A.; Spaller, M.; Stemmler, T.

2006-01-01

Friedreich's ataxia, an autosomal cardio- and neurodegenerative disorder that affects 1 in 50 000 humans, is caused by decreased levels of the protein frataxin. Although frataxin is nuclear-encoded, it is targeted to the mitochondrial matrix and necessary for proper regulation of cellular iron homeostasis. Frataxin is required for the cellular production of both heme and iron-sulfur (Fe-S) clusters. Monomeric frataxin binds with high affinity to ferrochelatase, the enzyme involved in iron insertion into porphyrin during heme production. Monomeric frataxin also binds to Isu, the scaffold protein required for assembly of Fe-S cluster intermediates. These processes (heme and Fe-S cluster assembly) share requirements for iron, suggesting that monomeric frataxin might function as the common iron donor. To provide a molecular basis to better understand frataxin's function, we have characterized the binding properties and metal-site structure of ferrous iron bound to monomeric yeast frataxin. Yeast frataxin is stable as an iron-loaded monomer, and the protein can bind two ferrous iron atoms with micromolar binding affinity. Frataxin amino acids affected by the presence of iron are localized within conserved acidic patches located on the surfaces of both helix-1 and strand-1. Under anaerobic conditions, bound metal is stable in the high-spin ferrous state. The metal-ligand coordination geometry of both metal-binding sites is consistent with a six-coordinate iron-(oxygen/nitrogen) based ligand geometry, surely constructed in part from carboxylate and possibly imidazole side chains coming from residues within these conserved acidic patches on the protein. On the basis of our results, we have developed a model for how we believe yeast frataxin interacts with iron

15N Hyperpolarization of Imidazole-15N2 for Magnetic Resonance pH Sensing via SABRE-SHEATH.

Science.gov (United States)

Shchepin, Roman V; Barskiy, Danila A; Coffey, Aaron M; Theis, Thomas; Shi, Fan; Warren, Warren S; Goodson, Boyd M; Chekmenev, Eduard Y

2016-06-24

15 N nuclear spins of imidazole- 15 N 2 were hyperpolarized using NMR signal amplification by reversible exchange in shield enables alignment transfer to heteronuclei (SABRE-SHEATH). A 15 N NMR signal enhancement of ∼2000-fold at 9.4 T is reported using parahydrogen gas (∼50% para-) and ∼0.1 M imidazole- 15 N 2 in methanol:aqueous buffer (∼1:1). Proton binding to a 15 N site of imidazole occurs at physiological pH (p K a ∼ 7.0), and the binding event changes the 15 N isotropic chemical shift by ∼30 ppm. These properties are ideal for in vivo pH sensing. Additionally, imidazoles have low toxicity and are readily incorporated into a wide range of biomolecules. 15 N-Imidazole SABRE-SHEATH hyperpolarization potentially enables pH sensing on scales ranging from peptide and protein molecules to living organisms.

Theoretical prediction of the mechanical properties of zeolitic imidazolate frameworks (ZIFs)

KAUST Repository

Zheng, Bin; Zhu, Yihan; Fu, Fang; Wang, Lian Li; Wang, Jinlei; Du, Huiling

2017-01-01

A good resistance against mechanical stress is essential for the utilization of metal-organic frameworks (MOFs) in practical applications such as gas sorption, separation, catalysis or energy conversion. Here, we report on the successful modification of the mechanical properties of zeolitic imidazolate frameworks (ZIFs) achieved through a substitution of the terminal group. The mechanical modulus of SALEM-2 was found to significantly improve when the -H groups at position 2 of the imidazole linkers were replaced with electron withdrawing groups (-CHO, -Cl, or -Br). The charge distribution and electron density were analyzed to reveal the mechanism behind the observed variation of the elastic stiffness. Furthermore, ZIF-I with a -I group at position 2 of the imidazole linkers was predicted to exhibit an excellent mechanical strength in our study and then prepared experimentally. The results indicate that an inconspicuous change of the structure of ZIFs, i.e., additional groups strengthening the ZnN4 tetrahedron, will lead to a stiffer framework.

Theoretical prediction of the mechanical properties of zeolitic imidazolate frameworks (ZIFs)

KAUST Repository

Zheng, Bin

2017-08-25

A good resistance against mechanical stress is essential for the utilization of metal-organic frameworks (MOFs) in practical applications such as gas sorption, separation, catalysis or energy conversion. Here, we report on the successful modification of the mechanical properties of zeolitic imidazolate frameworks (ZIFs) achieved through a substitution of the terminal group. The mechanical modulus of SALEM-2 was found to significantly improve when the -H groups at position 2 of the imidazole linkers were replaced with electron withdrawing groups (-CHO, -Cl, or -Br). The charge distribution and electron density were analyzed to reveal the mechanism behind the observed variation of the elastic stiffness. Furthermore, ZIF-I with a -I group at position 2 of the imidazole linkers was predicted to exhibit an excellent mechanical strength in our study and then prepared experimentally. The results indicate that an inconspicuous change of the structure of ZIFs, i.e., additional groups strengthening the ZnN4 tetrahedron, will lead to a stiffer framework.

Extreme Flexibility in a Zeolitic Imidazolate Framework

DEFF Research Database (Denmark)

Wharmby, M.T.; Henke, S.; Bennett, T.D.

2015-01-01

Desolvated zeolitic imidazolate framework ZIF-4(Zn) undergoes a discontinuous porous to dense phase transition on cooling through 140 K, with a 23% contraction in unit cell volume. The structure of the non-porous, low temperature phase was determined from synchrotron X-ray powder diffraction data...

A Novel Tetrasubstituted Imidazole as a Prototype for the Development of Anti-inflammatory Drugs.

Science.gov (United States)

Nascimento, Marcus Vinicius P S; Munhoz, Antonio C M; Theindl, Lais C; Mohr, Eduarda Talita B; Saleh, Najla; Parisotto, Eduardo B; Rossa, Thaís A; Zamoner, Ariane; Creczynski-Pasa, Tania B; Filippin-Monteiro, Fabíola B; Sá, Marcus M; Dalmarco, Eduardo Monguilhott

2018-04-14

Although inflammation is a biological phenomenon that exists to protect the host against infections and/or related problems, its unceasing activation results in the aggravation of several medical conditions. Imidazoles, whether natural or synthetic, are molecules related to a broad spectrum of biological effects, including anti-inflammatory properties. In this study, we screened eight novel small molecules of the imidazole class synthesized by our research group for their in vitro anti-inflammatory activity. The effect of the selected molecules was confirmed in an in vivo inflammatory model. We also analyzed whether the effects were caused by inhibition of nuclear factor kappa B (NF-κB) transcription factor transmigration. Of the eight imidazoles tested, methyl 1-allyl-2-(4-fluorophenyl)-5-phenyl-1H-imidazole-4-acetate (8) inhibited nitric oxide metabolites and pro-inflammatory cytokine (TNF-α, IL-6, and IL-1β) secretion in J774 macrophages stimulated with LPS. It also attenuated leukocyte migration and exudate formation in the pleural cavity of mice challenged with carrageenan. Furthermore, imidazole 8 reverted the oxidative stress pattern triggered by carrageenan in the pleural cavity by diminishing myeloperoxidase, superoxide dismutase, catalase, and glutathione S-transferase activities and reducing the production of nitric oxide metabolites and thiobarbituric acid-reactive substances. Finally, these effects can be attributed, at least in part, to the ability of this compound to prevent NF-κB transmigration. In this context, our results demonstrate that imidazole 8 has promising potential as a prototype for the development of a new anti-inflammatory drug to treat inflammatory conditions in which NF-κB and oxidative stress play a prominent role. Graphical Abstract ᅟ.

Synthesis, chemical and biological properties of the new mono- and bis-derivatives of imidazoles

Directory of Open Access Journals (Sweden)

E. V. Welchinska

2014-12-01

Full Text Available The aim of research. The problem of finding effective antitumour medical preparation with low toxicity is an important issue of medical and pharmaceutical chemistry. Knowledge of cancer cell features and its metabolism enables to predict the direction of chemical and biological research, to conduct a targeted synthesis of potential drugs, and to assess their applicability in oncological practice as antitumor agents. The purpose of work is to explain preformed heterocycles as purines, its synthesis and investigation of chemical and biological properties. After construction of the potential active structures we proposed the new method of original derivatives synthesis which are received on the base of imidazole, from one side, and fluorocontaining common anesthetic halothane (2-bromo-1,1,1-trifluoro-2-chloroethane from other side. Molecular complex of more perspective biologically active bis-imidazole with antitumour bacterial lectine has been received. With the purpose to synthesize potential antitumour compounds on the base of halothane and imidazole, new convenient methods for the preparation of original heterocyclic derivatives of imidazole have been described. The structure and composition of synthesized compound has been confirmed by the methods of elemental analysis, IR- and NMRІН-spectra. Materials and methods. The majority of the absolute organic solvents (benzene, dimethylformamide, ethyl ester employed in the present studies were distilled before their use. Organic solvents were dried over anhydrous magnesium sulfate or metallic sodium. Gas-liquid chromatography was carried out by Perkin Elmer chromatograph with UV-detector ("Perkin", Germany. IR spectra were recorded in a UR-20 spectrometer ("Charles Ceise Hena", Germany. The 1HNMR spectra were recorded in DMSO-d6 on a 200 MHz BrakerWP-200 ("Braker", Switzerland or Varian T-60 spectrometer ("Varian", USA. Investigation of critical toxicity of new compounds was carried out at

Cytokinin oxidase from Phaseolus vulgaris callus tissues. Enhanced in vitro activity of the enzyme in the presence of copper-imidazole complexes

International Nuclear Information System (INIS)

Chatfield, J.M.; Armstrong, D.J.

1987-01-01

The effects of metal ions on cytokinin oxidase activity extracted from callus tissues of Phaseolus vulgaris L. cv Great Northern have been examined using an assay based on the oxidation of N 6 -(Δ 2 -isopentenyl)-adenine-2,8- 3 H (i 6 Ade) to adenine (Ade). The addition of cupric ions to reaction mixtures containing imidazole buffer markedly enhanced cytokinin oxidase activity. In the presence of optimal concentrations of copper and imidazole, cytokinin oxidase activity was stimulated more than 20-fold. The effect was enzyme dependent, specific for copper, and observed only in the presence of imidazole. The substrate specificity of the copper-imidazole enhanced reaction, as judged by substrate competition tests, was the same as that observed in the absence of copper and imidazole. Similarly, in tests involving DEAE-cellulose chromatography, elution profiles of cytokinin oxidase activity determined using a copper-imidazole enhanced assay were identical to those obtained using an assay without copper and imidazole. On the basis of these results, the addition of copper and imidazole to reaction mixtures used to assay for cytokinin oxidase activity is judged to provide a reliable and specific assay of greatly enhanced sensitivity for the enzyme. The mechanism by which copper and imidazole enhance cytokinin oxidase activity is not certain, but the reaction catalyzed by the enzyme was not inhibited by anaerobic conditions when these reagents were present. This observation suggests that copper-imidazole complexes are substituting for oxygen in the reaction mechanism by which cytokinin oxidase effects cleavage of the N 6 -side chain of i 6 Ade

Designing inhibitors of cytochrome c/cardiolipin peroxidase complexes: mitochondria-targeted imidazole-substituted fatty acids.

Science.gov (United States)

Jiang, Jianfei; Bakan, Ahmet; Kapralov, Alexandr A; Silva, K Ishara; Huang, Zhentai; Amoscato, Andrew A; Peterson, James; Garapati, Venkata Krishna; Saxena, Sunil; Bayir, Hülya; Atkinson, Jeffrey; Bahar, Ivet; Kagan, Valerian E

2014-06-01

Mitochondria have emerged as the major regulatory platform responsible for the coordination of numerous metabolic reactions as well as cell death processes, whereby the execution of intrinsic apoptosis includes the production of reactive oxygen species fueling oxidation of cardiolipin (CL) catalyzed by cytochrome (Cyt) c. As this oxidation occurs within the peroxidase complex of Cyt c with CL, the latter represents a promising target for the discovery and design of drugs with antiapoptotic mechanisms of action. In this work, we designed and synthesized a new group of mitochondria-targeted imidazole-substituted analogs of stearic acid TPP-n-ISAs with various positions of the attached imidazole group on the fatty acid (n = 6, 8, 10, 13, and 14). By using a combination of absorption spectroscopy and EPR protocols (continuous wave electron paramagnetic resonance and electron spin echo envelope modulation) we demonstrated that TPP-n-ISAs indeed were able to potently suppress CL-induced structural rearrangements in Cyt c, paving the way to its peroxidase competence. TPP-n-ISA analogs preserved the low-spin hexa-coordinated heme-iron state in Cyt c/CL complexes whereby TPP-6-ISA displayed a significantly more effective preservation pattern than TPP-14-ISA. Elucidation of these intermolecular stabilization mechanisms of Cyt c identified TPP-6-ISA as an effective inhibitor of the peroxidase function of Cyt c/CL complexes with a significant antiapoptotic potential realized in mouse embryonic cells exposed to ionizing irradiation. These experimental findings were detailed and supported by all-atom molecular dynamics simulations. Based on the experimental data and computation predictions, we identified TPP-6-ISA as a candidate drug with optimized antiapoptotic potency. Copyright © 2014 Elsevier Inc. All rights reserved.

Local magnitudes of small contained explosions.

Energy Technology Data Exchange (ETDEWEB)

Chael, Eric Paul

2009-12-01

The relationship between explosive yield and seismic magnitude has been extensively studied for underground nuclear tests larger than about 1 kt. For monitoring smaller tests over local ranges (within 200 km), we need to know whether the available formulas can be extrapolated to much lower yields. Here, we review published information on amplitude decay with distance, and on the seismic magnitudes of industrial blasts and refraction explosions in the western U. S. Next we measure the magnitudes of some similar shots in the northeast. We find that local magnitudes ML of small, contained explosions are reasonably consistent with the magnitude-yield formulas developed for nuclear tests. These results are useful for estimating the detection performance of proposed local seismic networks.

Structural insight into activity enhancement and inhibition of H64A carbonic anhydrase II by imidazoles

Directory of Open Access Journals (Sweden)

Mayank Aggarwal

2014-03-01

Full Text Available Human carbonic anhydrases (CAs are zinc metalloenzymes that catalyze the hydration and dehydration of CO2 and HCO3−, respectively. The reaction follows a ping-pong mechanism, in which the rate-limiting step is the transfer of a proton from the zinc-bound solvent (OH−/H2O in/out of the active site via His64, which is widely believed to be the proton-shuttling residue. The decreased catalytic activity (∼20-fold lower with respect to the wild type of a variant of CA II in which His64 is replaced with Ala (H64A CA II can be enhanced by exogenous proton donors/acceptors, usually derivatives of imidazoles and pyridines, to almost the wild-type level. X-ray crystal structures of H64A CA II in complex with four imidazole derivatives (imidazole, 1-methylimidazole, 2-methylimidazole and 4-methylimidazole have been determined and reveal multiple binding sites. Two of these imidazole binding sites have been identified that mimic the positions of the `in' and `out' rotamers of His64 in wild-type CA II, while another directly inhibits catalysis by displacing the zinc-bound solvent. The data presented here not only corroborate the importance of the imidazole side chain of His64 in proton transfer during CA catalysis, but also provide a complete structural understanding of the mechanism by which imidazoles enhance (and inhibit when used at higher concentrations the activity of H64A CA II.

Unexpected Molecular Sieving Properties of Zeolitic Imidazolate Framework-8

KAUST Repository

Zhang, Chen; Lively, Ryan P.; Zhang, Ke; Johnson, Justin R.; Karvan, Oguz; Koros, William J.

2012-01-01

We studied molecular sieving properties of zeolitic imidazolate framework-8 (ZIF-8) by estimating the thermodynamically corrected diffusivities of probe molecules at 35 °C. From helium (2.6 Å) to iso-C 4H 10 (5.0 Å), the corrected diffusivity drops 14 orders of magnitude. Our results further suggest that the effective aperture size of ZIF-8 for molecular sieving is in the range of 4.0 to 4.2 Å, which is significantly larger than the XRD-derived value (3.4 Å) and between the well-known aperture size of zeolite 4A (3.8 Å) and 5A (4.3 Å). Interestingly, because of aperture flexibility, the studied C 4 hydrocarbon molecules that are larger than this effective aperture size still adsorb in the micropores of ZIF-8 with kinetic selectivities for iso-C 4H 8/iso-C 4H 10 of 180 and n-C 4H 10/iso-C 4H 10 of 2.5 × 10 6. These unexpected molecular sieving properties open up new opportunities for ZIF materials for separations that cannot be economically achieved by traditional microporous adsorbents such as synthetic zeolites. © 2012 American Chemical Society.

Unexpected Molecular Sieving Properties of Zeolitic Imidazolate Framework-8

KAUST Repository

Zhang, Chen

2012-08-16

We studied molecular sieving properties of zeolitic imidazolate framework-8 (ZIF-8) by estimating the thermodynamically corrected diffusivities of probe molecules at 35 °C. From helium (2.6 Å) to iso-C 4H 10 (5.0 Å), the corrected diffusivity drops 14 orders of magnitude. Our results further suggest that the effective aperture size of ZIF-8 for molecular sieving is in the range of 4.0 to 4.2 Å, which is significantly larger than the XRD-derived value (3.4 Å) and between the well-known aperture size of zeolite 4A (3.8 Å) and 5A (4.3 Å). Interestingly, because of aperture flexibility, the studied C 4 hydrocarbon molecules that are larger than this effective aperture size still adsorb in the micropores of ZIF-8 with kinetic selectivities for iso-C 4H 8/iso-C 4H 10 of 180 and n-C 4H 10/iso-C 4H 10 of 2.5 × 10 6. These unexpected molecular sieving properties open up new opportunities for ZIF materials for separations that cannot be economically achieved by traditional microporous adsorbents such as synthetic zeolites. © 2012 American Chemical Society.

The bolometric, infrared and visual absolute magnitudes of Mira variables

International Nuclear Information System (INIS)

Robertson, B.S.C.; Feast, M.W.

1981-01-01

Statistical parallaxes, as well as stars with individually known distances are used to derive bolometric and infrared absolute magnitudes of Mira (Me) variables. The derived bolometric magnitudes are in the mean about 0.75 mag fainter than recent estimates. The problem of determining the pulsation constant is discussed. Miras with periods greater than 150 days probably pulsate in the first overtone. Those of shorter periods are anomalous and may be fundamental pulsators. It is shown that the absolute visual magnitudes at mean light of Miras with individually determined distances are consistent with values derived by Clayton and Feast from statistical parallaxes. (author)

Comparative study between phenol and imidazole derivatives in radiolabeling of some steroid hormones

International Nuclear Information System (INIS)

Sallam, Kh.M.

2010-01-01

A phenol or imidazole ring is rarely present in steroid hormones, So, the molecule of steroid hormone requires chemical modification by addition of an iodinable residue like phenol or imedazole. So that the comparative study between phenol derivatives, include tyrosine methyl ester (TME) and tyramine, and imidazole derivatives, like histamine and histedine methyl ester (HME), for radiolabeling of some steroid hormones include estradiol and testosterone is the aim of the present study. The conjugation step was carried using mixed anhydride method and followed by radioiodination using iodogen as an oxidizing agent. Purification step was carried out using high performance liquid chromatography (HPLC). Optimization and validation of the tracer were carried out. Immunoreactivity of the all obtained tracers was check by using specific polyclonal antibodies. The results indicated that imidazols derivatives are more suitable from immunoreactivity view and storage period.

Screening for Methylated Poly(⌊-histidine with Various Dimethylimidazolium/Methylimidazole/Imidazole Contents as DNA Carrier

Directory of Open Access Journals (Sweden)

Shoichiro Asayama

2015-08-01

Full Text Available Methylated poly(l-histidine (PLH-Me, our original polypeptide, has controlled the contents of dimethylimidazolium, τ/π-methylimidazole and imidazole groups for efficient gene delivery. The screening for the PLH-Me as DNA carrier has been carried out by use of the PLH with 25 mol% (τ-methyl, 16 mol%; π-methyl, 17 mol%; deprotonated imidazole, 41 mol%, 68 mol% (τ-methyl, 16 mol%; π-methyl, 8 mol%; deprotonated imidazole, 8 mol% and 87 mol% (τ-methyl, 7 mol%; π-methyl, 4 mol%; deprotonated imidazole, 2 mol% dimethylimidazolium groups, that is, PLH-Me(25, PLH-Me(68 and PLH-Me(87, respectively. The screening of the chemical structure of PLH-Me has been carried out for DNA carrier properties, which are the stability of its DNA polyion complexes and gene expression. The DNA complexes with the 25 mol% and 68 mol% dimethylated PLH-Me possessed almost same ability to retain DNA, as compared with the 87 mol% dimethylated PLH-Me, which was examined by competitive exchange with dextran sulfate. From the gene transfection experiment against HepG2 cells, human hepatoma cell line, the PLH-Me(25/DNA complex was revealed to mediate highest gene expression. These results suggest that the dimethyl-imidazolium/methylimidazole/imidazole balance of the PLH-Me is important for DNA carrier design.

Synthesis of 1-(2,3-dihydroxypropyl)-2-nitro-1H-imidazole-2-14C and N-(2-hydroxyethyl)-2-(2-nitro-1H-imidazol-1-YL-2-14C)acetamide

International Nuclear Information System (INIS)

Fong, M.T.; Leaffer, M.A.

1986-01-01

We have prepared the 14 C-labeled analogs of NSC 261036, 1-(2,3-dihydroxypropyl)-2-nitro-1H-imidazole-2- 14 C, and NSC 301467, N-(2-hydroxyethyl)-2-(2-nitro-1H-imidazol-1-yl-2- 14 C) acetamide, for pharmacological, drug distribution, and mechanisms of action studies. The latter is an analog designed for lower toxicity and improved properties. The former is a metabolite of, and appears to be less toxic than, misonidazole. (author)

Iron and Zinc Complexes of Bulky Bis-Imidazole Ligands : Enzyme Mimicry and Ligand-Centered Redox Activity

NARCIS (Netherlands)

Folkertsma, E.

2016-01-01

The research described in this thesis is directed to the development of cheap and non-toxic iron-based homogeneous catalysts, using enzyme models and redox non-innocent ligands. Inspired by nature, the first approach focuses on the synthesis of structural models of the active site of non-heme iron

Imidazole derivatives as angiotensin II AT1 receptor blockers: Benchmarks, drug-like calculations and quantitative structure-activity relationships modeling

Science.gov (United States)

Alloui, Mebarka; Belaidi, Salah; Othmani, Hasna; Jaidane, Nejm-Eddine; Hochlaf, Majdi

2018-03-01

We performed benchmark studies on the molecular geometry, electron properties and vibrational analysis of imidazole using semi-empirical, density functional theory and post Hartree-Fock methods. These studies validated the use of AM1 for the treatment of larger systems. Then, we treated the structural, physical and chemical relationships for a series of imidazole derivatives acting as angiotensin II AT1 receptor blockers using AM1. QSAR studies were done for these imidazole derivatives using a combination of various physicochemical descriptors. A multiple linear regression procedure was used to design the relationships between molecular descriptor and the activity of imidazole derivatives. Results validate the derived QSAR model.

Benzimidazole and imidazole hexachlorocerates

Energy Technology Data Exchange (ETDEWEB)

Bayanov, A P; Burylev, B P; Temerdashev, Z A; Gusev, V I [Kubanskij Gosudarstvennyj Univ., Krasnodar (USSR)

1983-02-01

The process of hexachlorocerium acid with benzimidazole and imidazole interaction and the reaction products are investigated. The values of thermodynamic characteristics of the hexachlorocerium acid reaction with benzimidazole are equal: ..delta..Gsub(298K)=-16.5+-0.2 kJ/mol, ..delta..Hsub(298K)=-63.6+-0.8 kJ/mol, ..delta..Ssub(298K)=-157+-5 J/mol degrees. By the IR spectroscopy and radiography method the individuality of separated compounds has been found. The thermal stability of compounds is determined. The temperature dependence of splitting off chlorine atom from benzimidazole hexachlorocerate on pressure is investigated. Thermodynamic characteristics and activation energies of the process are calculated.

Benzimidazole and imidazole hexachlorocerates

International Nuclear Information System (INIS)

Bayanov, A.P.; Burylev, B.P.; Temerdashev, Z.A.; Gusev, V.I.

1983-01-01

The process of hexachlorocerium acid with benzimidazole and imidazole interaction and the reaction products are investigated. The values of thermodynamic characteristics of the hexachlorocerium acid reaction with benzimidazole are equal: ΔGsub(298K)=-16.5+-0.2 kJ/mol, ΔHsub(298K)=-63.6+-0.8 kJ/mol, ΔSsub(298K)=-157+-5 J/mol degrees. By the IR spectroscopy and radiography method the individuality of separated compounds has been found. The thermal stability of compounds is determined. The temperature de-- pendence of splitting off chlorine atom from benzimidazole hexachlorocerate on pressure is investigated. Thermodynamic characteristics and activation energies of the process are calculated

Ab initio study of the EFG at the N sites in imidazole

Energy Technology Data Exchange (ETDEWEB)

Brown Goncalves, Marcos, E-mail: browngon@if.usp.br [Universidade de Sao Paulo, Instituto de Fisica (Brazil); Di Felice, R. [National Center on Nanostructures and Biosystems at Surfaces (S3) of INFM-CNR (Italy); Poleshchuk, O. Kh. [Tomsk State Pedagogical University (Russian Federation); Petrilli, H. M. [Universidade de Sao Paulo, Instituto de Fisica (Brazil)

2008-01-15

We study the nuclear quadrupole interaction at the nitrogen sites in the molecular and crystalline phases of the imidazole compound. We use PAW which is a state-of-the-art method to calculate the electronic structure and electric field gradient at the nucleus in the framework of the density functional theory. The quadrupole frequencies at both imino and amino N sites are in excellent agreement with measurements. This is the first time that the electric field gradient at crystalline imidazole is correctly treated by an ab initio theoretical approach.

Electronic structure tautomerism, and mechanism of H-D exchange in imidazole aqueous solutions

International Nuclear Information System (INIS)

Borisov, Yu.A.; Vorob'eva, N.P.; Abronin, I.A.; Kolomiets, A.F.

1988-01-01

The imidazole electronic structure in a gaseous phase is studied taking into account the influence of solvation effects in aqueous solutions. Possible mechanisms of tautomeric transformations and H-D exchange reactions with water molecules are discussed. Using the quantum chemistry methods, it is shown that the intramolecular mechanism of imidazole isomerization in the gaseous phase and the aqueous solution is unprofitable, and the intermolecular mechanism can proceed through the stage of protonated and carbene form formation

Characteristics of North Korea nuclear test and KMA magnitude scale

Science.gov (United States)

Jeon, Y. S.; Lee, D.; Min, K.; Hwang, E. H.; Lee, J.; Park, E.; Jo, E.; Lee, M. S.

2017-12-01

Democratic People's Republic of Korea(DPRK) carried out 6th nuclear test on 3 Sep. 2017 at 03:30 UTC. Korea Meteorological Administration(KMA) announced to the public that the event took place in the DPRK's test site, Punggye-ri with the magnitude 5.7. This event is larger than previous one in terms of magnitude and showed that measured magnitude strongly depends on the frequency band of data. After we applied several magnitude scales such as Everdon(1967), Nuttli(1967), and Hong & Lee(2012) to this event, we found that magnitude ranges from 5.3 to 6.7 which depends on frequency band and epicentral distance of signal. 6th DPRK test experiment indicated that spectral amplitude ratio of 6th/5th near 2.37 Hz shows similar amplification compatible to relative spectral magnitude 5.7, while spectral amplitude ratio of 6th/5th near 1.0 Hz marks relative spectral magnitude about 6.1. Relative spectral magnitude varies with frequencies and decreases as frequency increase. We found that systematic non-linearity exists for spectral amplitude ratio of 6th/5th from 1.0 to 10.0 Hz, while it's characteristic is not found at 5th/4th and 4th/3th. A methodology is presented for determining mb(Pn) magnitude of underground nuclear explosions from local Pn phase. 582 waveforms from vertical component of broadband and acceleration seismographs at 120 stations in the epicenter distance from 340 to 800 km are used to calibrate mb(Pn) magnitude scaling for DPRK's nuclear tests. The mb(Pn) estimates of regional events for Korean Peninsula are determined to be mb(Pn) ? = log10(A) + 2.1164×log10(d) - 0.2721, where A is the peak-to-peak Pn amplitude in μm and d is the epicentral distance in km. Systematic non-linearity does not observed at frequency band from 0.1 to 1.0 Hz. The magnitude of 6th event is mb(Pn) 6.08 and mb(Pn) 4.52, 4.92, 4.84 and 5.03 for 2nd, 3rd, 4th and 5th respectively. Further research of applicable mb(Pn) magnitude scaling is required for all frequency band and

Contributions of molecular size, charge distribution, and specific amino acids to the iron-binding capacity of sea cucumber (Stichopus japonicus) ovum hydrolysates.

Science.gov (United States)

Sun, Na; Cui, Pengbo; Jin, Ziqi; Wu, Haitao; Wang, Yixing; Lin, Songyi

2017-09-01

This study investigated the contributions of molecular size, charge distribution and specific amino acids to the iron-binding capacity of sea cucumber (Stichopus japonicus) ovum hydrolysates (SCOHs), and further explored their iron-binding sites. It was demonstrated that enzyme type and degree of hydrolysis (DH) significantly influenced the iron-binding capacity of the SCOHs. The SCOHs produced by alcalase at a DH of 25.9% possessed the highest iron-binding capacity at 92.1%. As the hydrolysis time increased, the molecular size of the SCOHs decreased, the negative charges increased, and the hydrophilic amino acids were exposed to the surface, facilitating iron binding. Furthermore, the Fourier transform infrared spectra, combined with amino acid composition analysis, revealed that iron bound to the SCOHs primarily through interactions with carboxyl oxygen of Asp, guanidine nitrogen of Arg or nitrogen atoms in imidazole group of His. The formed SCOHs-iron complexes exhibited a fold and crystal structure with spherical particles. Copyright © 2017 Elsevier Ltd. All rights reserved.

Thermodynamics of organic mixtures containing amines. X. Phase equilibria for binary systems formed by imidazoles and hydrocarbons: Experimental data and modelling using DISQUAC

Energy Technology Data Exchange (ETDEWEB)

Domanska, Urszula; Zawadzki, Maciej [Physical Chemistry Division, Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw (Poland); Gonzalez, Juan Antonio, E-mail: jagl@termo.uva.e [G.E.T.E.F., Grupo Especializado en Termodinamica de Equilibrio entre Fases, Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, E-47071, Valladolid (Spain)

2010-04-15

(Solid + liquid) equilibrium (SLE) temperatures have been determined using a dynamic method for the systems (1H-imidazole, + benzene, + toluene, + hexane, or + cyclohexane; 1-methylimidazole + benzene, or + toluene, 2-methyl-1H-imidazole + benzene, + toluene, or + cyclohexane, and benzimidazole + benzene). In addition (liquid + liquid) equilibrium (LLE) temperatures have been obtained using a cloud point method for (1H-imidazole, + hexane, or + cyclohexane; 1-methylimidazole + toluene, and 2-methyl-1H-imidazole + cyclohexane). The measured systems show positive deviations from the Raoult's law, due to strong dipolar interactions between amine molecules related to the high dipole moment of imidazoles. On the other hand, DISQUAC interaction parameters for the contacts present in these solutions and for the amine/hydroxyl contacts in (1H-imidazole + 1-alkanol) mixtures have been determined. The model correctly represents the available data for the examined systems. Deviations between experimental and calculated SLE temperatures are similar to those obtained using the Wilson or NRTL equations, or the UNIQUAC association solution model. The quasichemical interaction parameters are the same for mixtures containing 1H-imidazole, 1-methylimidazole, or 2-methyl-1H-imidazole and hydrocarbons. This may be interpreted assuming that they are members of a homologous series. Benzimidazole behaves differently.

Thermodynamics of organic mixtures containing amines. X. Phase equilibria for binary systems formed by imidazoles and hydrocarbons: Experimental data and modelling using DISQUAC

International Nuclear Information System (INIS)

Domanska, Urszula; Zawadzki, Maciej; Gonzalez, Juan Antonio

2010-01-01

(Solid + liquid) equilibrium (SLE) temperatures have been determined using a dynamic method for the systems (1H-imidazole, + benzene, + toluene, + hexane, or + cyclohexane; 1-methylimidazole + benzene, or + toluene, 2-methyl-1H-imidazole + benzene, + toluene, or + cyclohexane, and benzimidazole + benzene). In addition (liquid + liquid) equilibrium (LLE) temperatures have been obtained using a cloud point method for (1H-imidazole, + hexane, or + cyclohexane; 1-methylimidazole + toluene, and 2-methyl-1H-imidazole + cyclohexane). The measured systems show positive deviations from the Raoult's law, due to strong dipolar interactions between amine molecules related to the high dipole moment of imidazoles. On the other hand, DISQUAC interaction parameters for the contacts present in these solutions and for the amine/hydroxyl contacts in (1H-imidazole + 1-alkanol) mixtures have been determined. The model correctly represents the available data for the examined systems. Deviations between experimental and calculated SLE temperatures are similar to those obtained using the Wilson or NRTL equations, or the UNIQUAC association solution model. The quasichemical interaction parameters are the same for mixtures containing 1H-imidazole, 1-methylimidazole, or 2-methyl-1H-imidazole and hydrocarbons. This may be interpreted assuming that they are members of a homologous series. Benzimidazole behaves differently.

Crystal structure of 4-tert-butyl-2-{2-[N-(3,3-dimethyl-2-oxobutyl-N-isopropylcarbamoyl]phenyl}-1-isopropyl-1H-imidazol-3-ium perchlorate

Directory of Open Access Journals (Sweden)

Olga V. Hordiyenko

2015-02-01

Full Text Available In the title salt, C26H40N3O2+·ClO4−, the positive charge of the organic cation is delocalized between the two N atoms of the imidazole ring. The C...;N bond distances are 1.338 (2 and 1.327 (3 Å. The substituents on the benzene ring are rotated almost orthogonal with respect to this ring due to the presence of the bulky isopropyl substituents. The dihedral angle between the benzene and imidazole rings is 75.15 (12°. Three of the O atoms of the anion are disordered over two sets of sites due to rotation around one of the O—Cl bonds. The ratio of the refined occupancies is 0.591 (14:0.409 (14. In the crystal, the cation and perchlorate anion are bound by an N—H...O hydrogen bond. In addition, the cation–anion pairs are linked into layers parallel to (001 by multiple weak C—H...O hydrogen bonds.

Magnitude determination for large underground nuclear explosions

Energy Technology Data Exchange (ETDEWEB)

Porter, Lawrence D [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

1970-05-15

A method is presented for determining the local magnitudes for large underground nuclear explosions. The Gutenberg-Richter nomograph is applied to the peak amplitudes for 24 large underground nuclear explosions that took place in Nevada. The amplitudes were measured at 18 California Wood-Anderson stations located 150-810 km from the explosion epicenter. The variation of the individual station magnitudes and magnitude corrections and the variation of the average and rms error estimates in the magnitude determinations are examined with respect to distance, azimuth, and event location. The magnitude prediction capability of the Gutenberg-Richter nomograph is examined on the basis of these two criteria, and certain corrections are suggested. The azimuthal dependence of the individual station magnitudes is investigated, and corrections for the California stations are calculated. Statistical weighting schemes for two-component data are employed, and the assumptions and limitations in the use of peak amplitudes are discussed. (author)

Structural, photophysical, and theoretical studies of imidazole-based excited-state intramolecular proton transfer molecules

Science.gov (United States)

Somasundaram, Sivaraman; Kamaraj, Eswaran; Hwang, Su Jin; Park, Sanghyuk

2018-02-01

Imidazole-based excited state intramolecular proton transfer (ESIPT) blue fluorescent molecules, 2-(1-(4-chlorophenyl)-4,5-diphenyl-1H-imidazol-2-yl)phenol (BHPI-Cl) and 2-(1-(4-bromophenyl)-4,5-diphenyl-1H-imidazol-2-yl)phenol (BHPI-Br) were designed and synthesized by Debus-Radziszewski method through a one-pot multicomponent reaction in high yield. The synthesized compounds were fully characterized by 1H NMR, 13C NMR, FT-IR, FT-Raman, GC-Mass, and elemental analysis. The molecular structures in single crystal lattice were studied by X-ray crystallographic analysis. Because of the intramolecular hydrogen bonding, hydroxyphenyl group is planar to the central imidazole ring, while the other phenyl rings gave distorted conformations to the central heterocyclic ring. BHPI-Cl and BHPI-Br molecules showed intense ESIPT fluorescence at 480 nm, because the two twisted phenyl rings on 4- and 5-positions have reduced intermolecular interaction between adjacent molecules in each crystal through a head-to-tail packing manner. Quantum chemical calculations of energies were carried out by (TD-)DFT using B3LYP/6-31G(d, p) basis set to predict the electronic absorption spectra of the compounds, and they showed good agreement between the computational and the experimental values. The thermal analyses of the synthesized molecules were also carried out by TGA/DSC method.

Hydrogen-deuterium exchange in imidazole as a tool for studying histidine phosphorylation.

Science.gov (United States)

Cebo, Małgorzata; Kielmas, Martyna; Adamczyk, Justyna; Cebrat, Marek; Szewczuk, Zbigniew; Stefanowicz, Piotr

2014-12-01

Isotope exchange at the histidine C2 atom of imidazole in D2O solution is well known to occur at a significantly slower rate than the exchange of amide protons. Analysis of the kinetics of this isotope-exchange reaction is proposed herein as a method of detecting histidine phosphorylation. This modification of His-containing peptides is challenging to pinpoint because of its instability under acidic conditions as well as during CID-MS analysis. In this work, we investigated the effect of phosphorylation of the histidine side chain in peptides on deuterium-hydrogen exchange (DHX) in the imidazole. The results demonstrate that phosphorylation dramatically slows the rate of the DHX reaction. This phenomenon can be applied to detect phosphorylation of peptides at the histidine residue (e.g., in enzymatic digests). We also found that the influence of the peptide sequence on the exchange kinetics is relatively small. A CID fragmentation experiment revealed that there was no detectable hydrogen scrambling in peptides deuterated at C2 of the imidazole ring. Therefore, MS/MS can be used to directly identify the locations of deuterium ions incorporated into peptides containing multiple histidine moieties.

Titanium-based zeolitic imidazolate framework for chemical fixation of carbon dioxide

Data.gov (United States)

U.S. Environmental Protection Agency — A titanium-based zeolitic imidazolate framework (Ti-ZIF) with high surface area and porous morphology has been synthesized and its application as a recyclable...

First catalytic hetero-Diels-Alder reaction of imidazole-2-thiones and in silico biological evaluation of the cycloadducts

NARCIS (Netherlands)

Eleftheriadis, Nikolaos; Samatidou, Evanthia; Neochoritis, Constantinos G.

The Lewis acid-catalyzed Diels-Alder reactions of suitably substituted imidazole-2-thiones with dienes were studied. It was found that the electron density of the imidazole core influenced the reaction, since electron withdrawing groups led to the novel spiro-derivatives 2 whereas electron donating

Building blocks for ionic liquids: Vapor pressures and vaporization enthalpies of 1-(n-alkyl)-imidazoles

International Nuclear Information System (INIS)

Emel'yanenko, Vladimir N.; Portnova, Svetlana V.; Verevkin, Sergey P.; Skrzypczak, Andrzej; Schubert, Thomas

2011-01-01

Highlights: → We measured vapor pressures of the 1-(n-alkyl)-imidazoles by transpiration method. → Variations on the alkyl chain length n were C 3 , C 5 -C 7 , and C 9 -C 10 . → Enthalpies of vaporization were derived from (p, T) dependencies. → Enthalpies of vaporization at 298.15 K were linear dependent on the chain length. - Abstract: Vapor pressures of the linear 1-(n-alkyl)-imidazoles with the alkyl chain C 3 , C 5 -C 7 , and C 9 -C 10 have been measured by the transpiration method. The molar enthalpies of vaporization Δ l g H m of these compounds were derived from the temperature dependencies of vapor pressures. A linear correlation of enthalpies of vaporization Δ l g H m (298.15 K) of the 1-(n-alkyl)-imidazoles with the chain length has been found.

A convenient method for 14C-labeling of 2-methylthio-1-[4-N-α-ethoxycarbonylbenzyl)-amino-benzyl] -5-hydroxymethyl-2-[14C]-1H-imidazole and 1-[4-N-α-ethoxy-carbonylbenzyl)-aminobenzyl]-5-hydroxymethyl-2-[14C] -1H-imidazole as potential antihypertensives

International Nuclear Information System (INIS)

Nader Saemian; Gholamhossein Shirvani; Mohsen Javaheri; Sayed Sajad Oliyaee

2012-01-01

The key synthetic intermediate, (2-mercapto-1-(4-nitrobenzyl)-1H-imidazol-5-yl)methanol-[2- 14 C], has been synthesized by using one pot procedure from potassium[ 14 C]-thiocyanate. It was converted to two nonpeptide angiotensin II receptor antagonists, 2-methylthio-1-[4-N-α-ethoxycarbonyl benzyl)-aminobenzyl]-5-hydroxymethyl-1H-imidazole-[2- 14 C] and 1-[4-N-α-ethoxy-carbonylbenzyl)-aminobenzyl] -5-hydroxymethyl-1H-imidazole-[2- 14 C] via a 3-step sequence synthetic pathway. (author)

Toward Anhydrous Proton Conductivity Based on Imidazole Functionalized Mesoporous Silica/Nafion Composite Membranes

International Nuclear Information System (INIS)

Amiinu, Ibrahim Saana; Li, Wei; Wang, Guangjin; Tu, Zhengkai; Tang, Haolin; Pan, Mu; Zhang, Haining

2015-01-01

Highlights: • Imidazole-functionalized mesoporous silica/Nafion composite is formed. • Electrostatic interaction between ionic clusters leads to enhanced molecular rigidity and T g . • Charge transfer resistance decreases with increase in temperature up to 130 °C. • The composite membrane exhibited considerable stability over 70 h at 130 °C. - Abstract: Although Nafion is regarded as the most preferred electrolyte membrane and often used as a benchmark for comparative evaluation of other electrolyte membranes, its wide spread for commercial PEM fuel cells is limited by the poor electrochemical properties at elevated temperatures and low relative humidity conditions. Herein, sol–gel synthesized mesoporous silica functionalized with a protogenic molecule (imidazole) is introduced into the Nafion matrix via a colloid mediated process. The formation of a stable colloid enables homogeneous dispersion of the silica-imidazole nanoparticles without aggregation. Under non-humidified conditions, the amphoteric and self-dissociative character of the tethered imidazole within the matrix functions as a transporting medium to facilitate proton conductivity. The structural and chemical phases are characterized, and qualitatively evaluated by XRD, TEM, FT-IR, TGA, and DMA. The results show that the average proton conductivity of the composite membrane with the optimal amount of functionalized nanoparticles increases progressively to 1.06 × 10 −2 S cm −1 at 130 °C, corresponding to an activation energy of 6.95 kJ mol −1 under non-humidified conditions. The mechanism governing the dynamics of proton conductivity and structural limitations as a function of temperature is discussed

Titanium-based zeolitic imidazolate framework for chemical fixation of carbon dioxide

Science.gov (United States)

A titanium-based zeolitic imidazolate framework (Ti-ZIF) with high surface area and porous morphology was synthesized and itsefficacy was demonstrated in the synthesis of cyclic carbonates from epoxides and carbon dioxide.

Alcohol and water adsorption in zeolitic imidazolate frameworks

KAUST Repository

Zhang, Ke; Lively, Ryan P.; Dose, Michelle E.; Brown, Andrew J.; Zhang, Chen; Chung, Jaeyub; Nair, Sankar; Koros, William J.; Chance, Ronald R.

2013-01-01

Alcohol (methanol, ethanol, 1-propanol, 2-propanol and 1-butanol) and water vapor adsorption in zeolitic imidazolate frameworks (ZIF-8, ZIF-71 and ZIF-90) with similar crystal sizes was systematically studied. The feasibility of applying these ZIF materials to the recovery of bio-alcohols is evaluated by estimating the vapor-phase alcohol-water sorption selectivity. © 2013 The Royal Society of Chemistry.

Di-μ-chlorido-bis(chlorido{2,2′-[3-(1H-imidazol-4-ylmethyl-3-azapentane-1,5-diyl]diphthalimide}copper(II

Directory of Open Access Journals (Sweden)

Xi-Xi Wang

2009-12-01

Full Text Available The centrosymmetric dinuclear CuII complex, [Cu2Cl4(C24H21N5O42], was synthesized by the reaction of CuCl2·2H2O with the tripodal ligand 2,2′-[3-(1H-imidazol-4-ylmethyl-3-azapentane-1,5-diyl]diphthalimide (L. Each of the CuII ions is coordinated by two N atoms from the ligand, two bridging Cl atoms and one terminal Cl atom. The CuII coordination can be best be described as a transition state between four- and five-coordination, since one of the bridging Cl atoms has a much longer Cu—Cl bond distance [2.7069 (13 Å] than the other [2.2630 (12 Å]. In addition, the Cu...Cu distance is 3.622 (1 Å. The three-dimensional structrure is generated by N—H...O, C—H...O and C—H...Cl hydrogen bonds and π–π interactions [centroid–centroid distances = 3.658 (4 and 4.020 (4 Å].

Comparative analysis of the heme iron electronic structure and stereochemistry in tetrameric rabbit hemoglobin and monomeric soybean leghemoglobin a using Mössbauer spectroscopy with a high velocity resolution

Science.gov (United States)

Alenkina, I. V.; Kumar, A.; Berkovsky, A. L.; Oshtrakh, M. I.

2018-02-01

A comparative study of tetrameric rabbit hemoglobin and monomeric soybean leghemoglobin a in the oxy- and deoxy-forms was carried out using 57Fe Mössbauer spectroscopy with a high velocity resolution in order to analyze the heme iron electronic structure and stereochemistry in relation to the Mössbauer hyperfine parameters. The Mössbauer spectra of tetrameric rabbit hemoglobin in both forms were fitted using two quadrupole doublets related to the 57Fe in ɑ- and β-subunits. In contrast, the Mössbauer spectra of monomeric soybean leghemoglobin a were fitted using: (i) two quadrupole doublets for the oxy-form related to two conformational states of the distal His E7 imidazole ring and different hydrogen bonding of oxygen molecule in the oxy-form and (ii) using three quadrupole doublets for deoxy-form related to three conformational states of the proximal His F8 imidazole ring. Small variations of Mössbauer hyperfine parameters related to small differences in the heme iron electronic structure and stereochemistry in tetrameric rabbit hemoglobin and monomeric soybean leghemoglobin a are discussed.

Cu(II) coordination polymers constructed by tetrafluoroterephthalic acid and varied imidazole-containing ligands: Syntheses, structures and properties

Science.gov (United States)

Liu, Kang; Sun, Yayong; Deng, Liming; Cao, Fan; Han, Jishu; Wang, Lei

2018-02-01

Six new copper(II) coordination polymers combining 2,3,5,6-tetrafluoroterephthalatic acid (H2tfBDC) and diverse imidazole-containing ligands, {[Cu(tfBDC)(1,2-bix)2]·2(H2O)}n (1), {Cu(tfBDC)(Im)2}n (2), {[Cu(1,4-bmimb)2(H2O)]·(tfBDC)·2(H2O)}n (3), {Cu(1,4-bimb)2(H2O)2·(tfBDC)}n (4), {[Cu(1,3-bix)2(H2O)2]·(tfBDC)·6(H2O)}n (5) and {[Cu(1,4-bix)2(H2O)2]·(tfBDC)·(1,4-bix)·4(H2O)}n (6) (1,2-bix = 1,2-bis(imidazole-1-ylmethyl)-benzene, Im = imidazole, 1,4-bmimb = 1,4-bis((2-methyl-1H-imidazol-1-yl)methyl)benzene, 1,4-bimb = 1,4-bis(imidazol-1-yl)-butane, 1,3-bix = 1,3-bis(imidazole-1-ylmethyl)-benzene, 1,4-bix = 1,4-bis(imidazole-1-ylmethyl)-benzene), have been obtained and structurally verified by single-crystal X-ray diffraction analyses and further characterized by powder X-ray diffraction (PXRD), elemental analyses and infrared spectroscopy (IR). Single crystal X-ray diffraction analysis revealed that 1 is 2D 4-connected sql topology (point symbol: {44·62}) based on a single metal ion node. Compound 2 is characterized as an infinite 1D chain structure, which is further extended into a 2D layer through N-H···O hydrogen bonds and then a 3D supramolecular architecture via π···π stacking interactions. Note that 2 was prepared through an in situ ligand reaction in which N,N'-carbonyldiimidazole (cdi) broke up into imidazole ligand. Compound 3 possesses a 3D 4-fold interpenetrated architecture with 4-connected dia topology (Schläfli symbol: {66}) in which tfBDC2- is stabilized in the channel by hydrogen bonds. Compounds 4-6 are all linear 1D coordination polymers. In 4, the free tfBDC2- ligand acts as a μ4-bridge to link four coordinated water molecules from the chain to construct a 2D structure via hydrogen bonds. While in 5 and 6, the uncoordinated tfBDC2- ligands and multimeric water clusters is responsible for the conversion of these 1D coordination polymers into 3D supramolecular assemblies through O-H⋯O hydrogen bonding interactions. Moreover

Dichloridobis[1-(2,4,6-trimethylphenyl-1H-imidazole-κN3]copper(II

Directory of Open Access Journals (Sweden)

Yantao Zhang

2013-11-01

Full Text Available In the title complex, [CuCl2(C12H14N22], the Cu2+ cation is situated on an inversion centre and is coordinated by two N atoms from symmetry-related 1-mesityl-1H-imidazole ligands and by two chloride anions in a slightly distorted square-planar geometry. In the organic ligand, the dihedral angle between the benzene ring of the mesityl moiety and the imidazole ring is 76.99 (18°. Weak intramolecular C—H...Cl hydrogen-bonding interactions consolidate the molecular conformation.

Study of Antibacterial Effect of Novel Thiazole, Imidazole and Tetrahydropyridine Derivatives against Escherichia coli

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Behzad Ghasemi

2016-01-01

Full Text Available > Introduction: Escherichia coli is one of the important pathogens in human with globalimportance. Because of the necessity for identification and the use of novel antibacterialcompounds against E. coli, in this present study we focused on the antibacterial effects ofsynthesized thiazole, imidazole and tetrahydropyridine derivatives on E. coli.Methods: For evaluation of antibacterial effect, the disk diffusion method was applied to measurethe growth inhibition zone diameter and broth micro-dilution was performed to determine theminimum inhibitory concentration (MIC.Results: Assessing the antibacterial effect showed that only 6d derivative of thiazole hadinhibitory effect on E. coli and the other thiazole, imidazole and tetrahydropyridine derivativeslacked any inhibitory result on this organism. The inhibitory effect of 6d derivative of thiazolewas MIC=125 and growth inhibition zone diameter of 16±0.1.Discussion: The antibacterial effect of thiazole, imidazole and tetrahydropyridine derivativesdiffers from each other and chemical linkages such as oxygen to thiazole ring in 6d derivative,could have reinforced this effect. The next step is determination of the toxicity and therapeuticeffects in the laboratory animals.

Trapped in imidazole: how to accumulate multiple photoelectrons on a black-absorbing ruthenium complex.

Science.gov (United States)

Zedler, Linda; Kupfer, Stephan; de Moraes, Inês Rabelo; Wächtler, Maria; Beckert, Rainer; Schmitt, Michael; Popp, Jürgen; Rau, Sven; Dietzek, Benjamin

2014-03-24

Ruthenium dyes incorporating a 4H-imidazole chromophore as a ligand exhibit a spectrally broad absorption in the UV/Vis region. Furthermore, they show the ability to store two electrons within the 4H-imidazole ligand. These features render them promising molecular systems, for example, as inter- or intramolecular electron relays. To optimize the structures with respect to their electron-storage capability, it is crucial to understand the impact of structural changes accompanying photoinduced charge transfer in the electronic intermediates of multistep electron-transfer processes. The photophysical properties of these (reactive) intermediates might impact the function of the molecular systems quite substantially. However, the spectroscopic study of short-lived intermediates in stepwise multielectron-transfer processes is experimentally challenging. To this end, this contribution reports on the electrochemical generation of anions identical to intermediate structures and their spectroscopic characterization by in situ resonance Raman and UV/Vis spectroelectrochemistry and computational methods. Thereby, an efficient two-electron pathway to the 4H-imidazole electron-accepting ligand is identified. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Near-IR TRGB Distance to Dwarf Elliptical Galaxy NGC 147

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A. Kang

2007-09-01

Full Text Available We report the distance modulus of nearby dwarf elliptical galaxy NGC 147 estimated from the Tip of Red-giant Branch (TRGB method applying to the color-magnitude diagrams and luminosity functions in the near-infrared JHK bands. Apparent magnitudes of TRGBs in each band are obtained by applying Savitzky-Golay filter to the luminosity functions, and the theoretical absolute magnitudes are estimated from Yonsei-Yale isochrones. The derived values of distance modulus to NGC 147 are (m-M=23.69±0.12, 23.78±0.17, and 23.85±0.22 for J, H, and K bands, respectively. Distance modulus in bolometric magnitude is also derived as (m-M=23.87±0.11. We compare the derived values of the TRGB distance modulus to NGC 147 in the near-infrared bands with the previous results in other bands.

Characterization and Solubilization of Pyrrole–Imidazole Polyamide Aggregates

OpenAIRE

Hargrove, Amanda E.; Raskatov, Jevgenij A.; Meier, Jordan L.; Montgomery, David C.; Dervan, Peter B.

2012-01-01

To optimize the biological activity of pyrrole–imidazole polyamide DNA-binding molecules, we characterized the aggregation propensity of these compounds through dynamic light scattering and fractional solubility analysis. Nearly all studied polyamides were found to form measurable particles 50–500 nm in size under biologically relevant conditions, while HPLC-based analyses revealed solubility trends in both core sequences and peripheral substituents that did not correlate with overall ionic c...

Regio- and Enantioselective N-Allylations of Imidazole, Benzimidazole, and Purine Heterocycles Catalyzed by Single-Component Metallacyclic Iridium Complexes

Science.gov (United States)

Stanley, Levi M.

2010-01-01

Highly regio- and enantioselective iridium-catalyzed N-allylations of benzimidazoles, imidazoles, and purines have been developed. N-Allylated benzimidazoles and imidazoles were isolated in high yields (up to 97%) with high branched-to-linear selectivity (up to 99:1) and enantioselectivity (up to 98% ee) from the reactions of benzimidazole and imidazole nucleophiles with unsymmetrical allylic carbonates in the presence of single component, ethylene-bound, metallacyclic iridium catalysts. N-Allylated purines were also obtained in high yields (up to 91%) with high N9:N7 selectivity (up to 96:4), high branched-to-linear selectivity (98:2), and high enantioselectivity (up to 98% ee) under similar conditions. The reactions encompass a range of benzimidazole, imidazole, and purine nucleophiles, as well as a variety of unsymmetrical aryl, heteroaryl, and aliphatic allylic carbonates. Competition experiments between common amine nucleophiles and the heterocyclic nitrogen nucleophiles studied in this work illustrate the effect of nucleophile pKa on the rate of iridium-catalyzed N-allylation reactions. Kinetic studies on the allylation of benzimidazole catalyzed by metallacyclic iridium-phosphoramidite complexes, in combination with studies on the deactivation of these catalysts in the presence of heterocyclic nucleophiles, provide insight into the effects of the structure of the phosphoramidite ligands on the stability of the metallacyclic catalysts. The data obtained from these studies has led to the development of N-allylations of benzimidazoles and imidazoles in the absence of an exogenous base. PMID:19480431

Zeolitic imidazolate framework-8-derived N-doped porous carbon coated olive-shaped FeOx nanoparticles for lithium storage

Science.gov (United States)

Gan, Qingmeng; Zhao, Kuangmin; He, Zhen; Liu, Suqin; Li, Aikui

2018-04-01

We propose a new strategy to uniformly coat zeolitic imidazolate framework-8 (ZIF-8) on iron oxides containing no Zn to obtain an α-Fe2O3@ZIF-8 composite. After carbonization, the α-Fe2O3@ZIF-8 transforms into iron oxides@N-doped porous carbon (FeOx@NC). The uniform N-doped porous carbon layer gives rise to a superior electrical conductivity, highly-increased specific BET surface area (179.2 m2 g-1), and abundant mesopores for the FeOx@NC composite. When served as the LIB anode, the FeOx@NC shows a high reversible capacity (of 1064 mA h g-1 at 200 mA g-1), excellent rate performance (of 198.1 mA h g-1 at 10000 mA g-1) as well as brilliant long-term cyclability (with a capacity retention of 93.3% after 800 cycles), which are much better than those of the FeOx@C and pristine FeOx anodes. Specifically, the Li-ion intercalation pseudocapacitive behavior of the FeOx@NC anode is improved by this N-doped porous carbon coating, which is beneficial for rapid Li-ion insertion/extraction processes. The excellent electrochemical performance of FeOx@NC should be ascribed to the increased electrolyte penetration areas, improved electrical conductivity, boosted lithium storage kinetics, and shortened Li-ion transport length.

Synthesis and characterization of novel polyamide-ethers based on bis-imidazole containing bulky aryl pendant groups

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Seyed Mahdi Saadati

2013-01-01

Full Text Available A series of novel polyamide-ethers (PAEs based on bis-imidazole containing bulky aryl pendant groups was prepared by direct polycondensation of a diamine, 4-(1-(4-(4-(2-(4-aminophenyl-4,5-diphenyl-1H-imidazol-1-ylphenoxyphenyl-4,5-diphenyl-1H-imidazol-2-ylbenzenamine (DABI, and various dicarboxylic acids. All the resulting polyamide-ethers were amorphous with inherent viscosities ranged from 0.52 to 0.61 dL/g and were readily soluble in many organic solvents which could be solution-cast into transparent and tough films. The glass transition temperatures (Tg of these polymers were affected considerably by their chemical structure and ranged from 230 to 310 ºC. They had useful levels of thermal stability associated with relatively high temperatures of 10% weight loss (T10 in the range of 329-399 ºC in air atmosphere.

Cd(II)-coordination polymers based on tetracarboxylic acid and diverse bis(imidazole) ligands: Synthesis, structural diversity and photoluminescence properties

Energy Technology Data Exchange (ETDEWEB)

Arıcı, Mürsel, E-mail: marici@ogu.edu.tr [Department of Chemistry, Faculty of Arts and Sciences, Eskişehir Osmangazi University, 26480 Eskişehir (Turkey); Yeşilel, Okan Zafer [Department of Chemistry, Faculty of Arts and Sciences, Eskişehir Osmangazi University, 26480 Eskişehir (Turkey); Taş, Murat [Department of Science Education, Education Faculty, Ondokuz Mayıs University, 55139 Samsun (Turkey)

2017-01-15

Three new Cd(II)-coordination polymers, namely, ([Cd{sub 2}(μ{sub 6}-ao{sub 2}btc)(μ-1,5-bipe){sub 2}]·2H{sub 2}O){sub n} (1), ([Cd{sub 2}(μ{sub 6}-ao{sub 2}btc)(μ-1,4-bix){sub 2}]{sub n}·2DMF) (2) and ([Cd{sub 2}(μ{sub 8}-abtc)(μ-1,4-betix)]·DMF·H{sub 2}O){sub n} (3) (ao{sub 2}btc=di-oxygenated form of 3,3′,5,5′-azobenzenetetracarboxylate, 1,5-bipe: 1,5-bis(imidazol-1yl)pentane, 1,4-bix=1,4-bis(imidazol-1ylmethyl)benzene, 1,4-betix=1,4-bis(2-ethylimidazol-1ylmethyl)benzene) were synthesized with 3,3′,5,5′-azobenzenetetracarboxylic acid and flexible, semi-flexible and semi-flexible substituted bis(imidazole) linkers. They were characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction, powder X-ray diffractions (PXRD) and thermal analyses (TG/DTA). Complexes 1–3 exhibited structural diversities depending on flexible, semi-flexible and semi-flexible substituted bis(imidazole) ligands. Complex 1 was 2D structure with 3,6L18 topology. Complex 2 had a 3D pillar-layered framework with the rare sqc27 topology. When semi-flexible substituted bis(imidazole) linker was used, 3D framework of complex 3 was obtained with the paddlewheel Cd{sub 2}(CO{sub 2}){sub 4}-type binuclear SBU. Moreover, thermal and photoluminescence properties of the complexes were determined in detailed. - Graphical abstract: In this study, three novel Cd(II)-coordination polymers were synthesized with 3,3′,5,5′-azobenzenetetracarboxylic acid and flexible, semi-flexible and semi-flexible substituted bis(imidazole) linkers. They were characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction, powder X-ray diffractions (PXRD) and thermal analyses (TG/DTA). Complexes 1–3 exhibited structural diversities depending on flexible, semi-flexible and semi-flexible substituted bis(imidazole) ligands. Complex 1 was 2D structure with 3,6L18 topology. Complex 2 had a 3D pillar-layered framework with the rare sqc27 topology. When semi

Ultrasound-promoted synthesis of (4 or 5-aryl-2-aryloyl-(1H-imidazoles in water

Directory of Open Access Journals (Sweden)

Behzad Khalili

2014-01-01

Full Text Available A green and efficient method for the synthesis of (4 or 5-aryl-2-aryloyl-(1H-imidazoles via self-condensation reaction of arylglyoxal hydrates in the presence of ammonium acetate using water as solvent under ultrasonic irradiation was reported. The reactions proceeded in high yields and very short reaction time. Introduced procedure is completely ecofriendly and don’t need any toxic organic solvent in all performing steps. In addition we use computational chemistry for acquiring some information about the thermochemistry and geometrical structure of these imidazole derivatives.

Numerical magnitude processing in abacus-trained children with superior mathematical ability: an EEG study.

Science.gov (United States)

Huang, Jian; Du, Feng-lei; Yao, Yuan; Wan, Qun; Wang, Xiao-Song; Chen, Fei-Yan

2015-08-01

Distance effect has been regarded as the best established marker of basic numerical magnitude processes and is related to individual mathematical abilities. A larger behavioral distance effect is suggested to be concomitant with lower mathematical achievement in children. However, the relationship between distance effect and superior mathematical abilities is unclear. One could get superior mathematical abilities by acquiring the skill of abacus-based mental calculation (AMC), which can be used to solve calculation problems with exceptional speed and high accuracy. In the current study, we explore the relationship between distance effect and superior mathematical abilities by examining whether and how the AMC training modifies numerical magnitude processing. Thus, mathematical competencies were tested in 18 abacus-trained children (who accepted the AMC training) and 18 non-trained children. Electroencephalography (EEG) waveforms were recorded when these children executed numerical comparison tasks in both Arabic digit and dot array forms. We found that: (a) the abacus-trained group had superior mathematical abilities than their peers; (b) distance effects were found both in behavioral results and on EEG waveforms; (c) the distance effect size of the average amplitude on the late negative-going component was different between groups in the digit task, with a larger effect size for abacus-trained children; (d) both the behavioral and EEG distance effects were modulated by the notation. These results revealed that the neural substrates of magnitude processing were modified by AMC training, and suggested that the mechanism of the representation of numerical magnitude for children with superior mathematical abilities was different from their peers. In addition, the results provide evidence for a view of non-abstract numerical representation.

A catalog of observed nuclear magnitudes of Jupiter family comets

Science.gov (United States)

Tancredi, G.; Fernández, J. A.; Rickman, H.; Licandro, J.

2000-10-01

A catalog of a sample of 105 Jupiter family (JF) comets (defined as those with Tisserand constants T > 2 and orbital periods P International Comet Quarterly Archive of Cometary Photometric Data, the Minor Planet Center (MPC) data base, IAU Circulars, International Comet Quarterly, and a few papers devoted to some particular comets, together with our own observations. Photometric data previous to 1990 have mainly been taken from the Comet Light Curve Catalogue (CLICC) compiled by Kamél (\\cite{kamel}). We discuss the reliability of the reported nuclear magnitudes in relation to the inherent sources of errors and uncertainties, in particular the coma contamination often present even at large heliocentric distances. A large fraction of the JF comets of our sample indeed shows various degrees of activity at large heliocentric distances, which is correlated with recent downward jumps in their perihelion distances. The reliability of coma subtraction methods to compute the nuclear magnitude is also discussed. Most absolute nuclear magnitudes are found in the range 15 - 18, with no magnitudes fainter than H_N ~ 19.5. The catalog can be found at: http://www.fisica.edu.uy/ ~ gonzalo/catalog/. Table 2 and Appendix B are only available in electronic form at http://www.edpsciences.org Table 5 is also available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

Efficacy of iron fortification compared to iron supplementation among Vietnamese schoolchildren.

Science.gov (United States)

Thi Le, Huong; Brouwer, Inge D; Burema, Jan; Nguyen, Khan Cong; Kok, Frans J

2006-12-05

The effect of iron fortification is generally assumed to be less than iron supplementation; however, the magnitude of difference in effects is not known. The present study aims to compare the efficacy of these two strategies on anaemia and iron status. After screening on low Hb, 425 anaemic children in six primary schools in Tam Nong district of Phu Tho province were included in a randomized, placebo-controlled trial comparing two groups receiving iron fortified instant noodles or iron supplementation for 6 months and a control group, with children in all groups having been dewormed. Blood samples were collected before and after intervention for haemoglobin, serum ferritin (SF), serum transferrin receptor (TfR), C-reactive protein (CRP), and haemoglobinopathies analysis. Regression analysis was used to assess the effect of iron fortification and iron supplementation on haemoglobin concentration, SF, TfR, body iron, and anaemic status as outcome variables. The improvement of haemoglobin, SF, and body iron level in the group receiving iron fortification was 42% (2.6 g/L versus 6.2 g/L), 20% (23.5 microg/L versus 117.3 microg/L), and 31.3% (1.4 mg/kg versus 4.4 mg/kg) of that in the iron supplementation group. The prevalence of anaemia dropped to 15.1% in the control group, with an additional reduction of anaemia of 8.5% in the iron supplementation group. The additional reduction due to iron fortification was 5.4%, which amounts to well over 50% of the impact of supplementation. In conclusion, the efficacy of iron fortification based on reduction of prevalence of anaemia, and on the change in haemoglobin level, is about half of the maximum impact of supplementation in case of optimal compliance. Thus, in a population of anaemic children with mild iron deficiency, iron fortification should be the preferred strategy to combat anaemia.

Parallel Synthesis of a Library of Symmetrically- and Dissymmetrically-disubstituted Imidazole-4,5-dicarboxamides Bearing Amino Acid Esters

Directory of Open Access Journals (Sweden)

Rosanna Solinas

2009-01-01

Full Text Available The imidazole-4,5-dicarboxylic acid scaffold is readily derivatized with amino acid esters to afford symmetrically- and dissymmetrically-disubstituted imidazole-4,5-dicarboxamides with intramolecularly hydrogen bonded conformations that predispose the presentation of amino acid pharmacophores. In this work, a total of 45 imidazole-4,5-dicarboxamides bearing amino acid esters were prepared by parallel synthesis. The library members were purified by column chromatography on silica gel and the purified compounds characterized by LC-MS with LC detection at 214 nm. A selection of the final compounds was also analyzed by 1H-NMR spectroscopy. The analytically pure final products have been submitted to the Molecular Library Small Molecule Repository (MLSMR for screening in the Molecular Library Screening Center Network (MLSCN as part of the NIH Roadmap.

The crystal structure of tryptophan hydroxylase with bound amino acid substrate

DEFF Research Database (Denmark)

Windahl, Michael Skovbo; Petersen, Charlotte Rode; Christensen, Hans Erik Mølager

2008-01-01

Tryptophan hydroxylase (TPH) is a mononuclear non-heme iron enzyme, which catalyzes the reaction between tryptophan, O2, and tetrahydrobiopterin (BH4) to produce 5-hydroxytryptophan and 4a-hydroxytetrahydrobiopterin. This is the first and rate-limiting step in the biosynthesis of the neurotransmi......Tryptophan hydroxylase (TPH) is a mononuclear non-heme iron enzyme, which catalyzes the reaction between tryptophan, O2, and tetrahydrobiopterin (BH4) to produce 5-hydroxytryptophan and 4a-hydroxytetrahydrobiopterin. This is the first and rate-limiting step in the biosynthesis...... acid hydroxylase with bound natural amino acid substrate. The iron coordination can be described as distorted trigonal bipyramidal coordination with His273, His278, and Glu318 (partially bidentate) and one imidazole as ligands. The tryptophan stacks against Pro269 with a distance of 3.9 Å between...

Synthesis, characterization and toxicity of azanonaborane-containing imidazoles for boron neutron capture therapy

International Nuclear Information System (INIS)

El-Zaria, Mohamed E.; Genady, Afaf R.; Gabel, Detlef

2006-01-01

The exo-NH 2 R group of the azanonaborane of the type [(RH 2 N)B 8 H 11 NHR] can be exchanged by one hetero-nitrogen atom of the imidazole ring. In the case of histamine, the exchange takes place on the aliphatic amino group, the hetero-nitrogen atom of the imidazole ring or both of them. In vitro experiments using B16 melanoma cells showed that incorporation of B 8 N cluster unit into primary amino group of the histamine increases the compound's toxicity. In contrast, this specificity for cytotoxicity effect was not observed in the case of histamine containing two B 8 N clusters which was relatively nontoxic and did not inhibit colony formation up to 2 mM. (author)

Silylation of leached-vermiculites following reaction with imidazole and copper sorption behavior

Energy Technology Data Exchange (ETDEWEB)

Santos, Saloana S.G.; Pereira, Mariana B.B. [Chemistry Department of Paraíba Federal University, João Pessoa, Paraíba (Brazil); Almeida, Ramon K.S. [Instituto de Química, Universidade Estadual de Campinas, Caixa Postal 6154, 13083-970 Campinas, São Paulo (Brazil); Souza, Antônio G. [Chemistry Department of Paraíba Federal University, João Pessoa, Paraíba (Brazil); Fonseca, Maria G., E-mail: mgardennia@quimica.ufpb.br [Chemistry Department of Paraíba Federal University, João Pessoa, Paraíba (Brazil); Jaber, M. [Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 8220, Laboratoire d' archéologie moléculaire et structurale (LAMS), Boîte courrier 225, 4 place Jussieu, 75005 Paris (France)

2016-04-05

Highlights: • Silylated vermiculites reacted covalently with imidazole. • Modified vermiculites adsorbed copper from aqueous solution. • Copper retention in all solids occurred at rapid time of 80 min. • Higher organic content on the solid improved the copper adsorption. - Abstract: Organically modified vermiculites were synthesized by previous silylation of three leached vermiculites, V0.3Cl, V0.5Cl and V0.8Cl, under anhydrous conditions following reaction with imidazole (Im), which acted as chelating agent for copper retention. Elemental analysis, X-ray diffraction, infrared spectroscopy, scanning electronic microscopy, transmission electron microscopy, {sup 29}Si and {sup 13}C NMR and nitrogen adsorption/desorption measurements were used to characterize pristine, leached and organofunctionalized solids. X-ray photoelectron spectroscopy (XPS) was used to evaluate the surface after copper sorption. Parameters such as contact time, pH and initial cation concentration for the adsorption of Cu(II) ions were investigated. The adsorption equilibrium data were fitted using the Langmuir isotherm model and the monolayer adsorption capacities were 2.38, 2.52 and 2.69 mmol g{sup −1} for V0.5Cl-Im, V0.3Cl-Im and V0.8Cl-Im, respectively, at pH 6.0 and 298 K for a time reaction of 80 min. The sorption rates were described by pseudo-second-order kinetics. The chloropropyl imidazole vermiculites are promising adsorbents for the rapid removal of Cu(II) ions from aqueous solution.

An Imidazole based probe for relay recognition of Cu and OH ions ...

Indian Academy of Sciences (India)

biological activities.1 Biological activity of imidazole derivatives is the main motive for ... These systems use physical or chemical inputs to gen- erate outputs based on a set ... exhibit α-glucosidase inhibition to treat diabetes.21. 2. Experimental.

Controlled synthesis of phase-pure zeolitic imidazolate framework Co-ZIF-9

NARCIS (Netherlands)

Öztürk, Z.; Hofmann, J.P.; Lutz, M.; Mazaj, M.; Zabukovec Logar, N.; Weckhuysen, B.M.

2015-01-01

The synthesis of phase-pure Co-ZIF-9, an important cobalt-based zeolitic imidazolate framework, could be achieved by modification of the reported synthesis procedure through pH adjustment of the starting synthesis mixture. The phase-pure Co-ZIF-9 material obtained has been characterized by a

Syntheses, structures, and properties of imidazolate-bridged Cu(II)-Cu(II) and Cu(II)-Zn(II) dinuclear complexes of a single macrocyclic ligand with two hydroxyethyl pendants.

Science.gov (United States)

Li, Dongfeng; Li, Shuan; Yang, Dexi; Yu, Jiuhong; Huang, Jin; Li, Yizhi; Tang, Wenxia

2003-09-22

The imidazolate-bridged homodinuclear Cu(II)-Cu(II) complex, [(CuimCu)L]ClO(4).0.5H(2)O (1), and heterodinuclear Cu(II)-Zn(II) complex, [(CuimZnL(-)(2H))(CuimZnL(-)(H))](ClO(4))(3) (2), of a single macrocyclic ligand with two hydroxyethyl pendants, L (L = 3,6,9,16,19,22-hexaaza-6,19-bis(2-hydroxyethyl)tricyclo[22,2,2,2(11,14)]triaconta-1,11,13,24,27,29-hexaene), have been synthesized as possible models for copper-zinc superoxide dismutase (Cu(2),Zn(2)-SOD). Their crystal structures analyzed by X-ray diffraction methods have shown that the structures of the two complexes are markedly different. Complex 1 crystallizes in the orthorhombic system, containing an imidazolate-bridged dicopper(II) [Cu-im-Cu](3+) core, in which the two copper(II) ions are pentacoordinated by virtue of an N4O environment with a Cu.Cu distance of 5.999(2) A, adopting the geometry of distorted trigonal bipyramid and tetragonal pyramid, respectively. Complex 2 crystallizes in the triclinic system, containing two similar Cu-im-Zn cores in the asymmetric unit, in which both the Cu(II) and Zn(II) ions are pentacoordinated in a distorted trigonal bipyramid geometry, with the Cu.Zn distance of 5.950(1)/5.939(1) A, respectively. Interestingly, the macrocyclic ligand with two arms possesses a chairlike (anti) conformation in complex 1, but a boatlike (syn) conformation in complex 2. Magnetic measurements and ESR spectroscopy of complex 1 have revealed the presence of an antiferromagnetic exchange interaction between the two Cu(II) ions. The ESR spectrum of the Cu(II)-Zn(II) heterodinuclear complex 2 displayed a typical signal for mononuclear trigonal bipyramidal Cu(II) complexes. From pH-dependent ESR and electronic spectroscopic studies, the imidazolate bridges in the two complexes have been found to be stable over broad pH ranges. The cyclic voltammograms of the two complexes have been investigated. Both of the two complexes can catalyze the dismutation of superoxide and show rather high activity.

Hybrid Zeolitic Imidazolate Frameworks: Controlling Framework Porosity and Functionality by Mixed-Linker Synthesis

KAUST Repository

Thompson, Joshua A.; Blad, Catherine R.; Brunelli, Nicholas A.; Lydon, Megan E.; Lively, Ryan P.; Jones, Christopher W.; Nair, Sankar

2012-01-01

Zeolitic imidazolate frameworks (ZIFs) are a subclass of nanoporous metal-organic frameworks (MOFs) that exhibit zeolite-like structural topologies and have interesting molecular recognition properties, such as molecular sieving and gate

Iron-dependent regulation of hepcidin in Hjv-/- mice: evidence that hemojuvelin is dispensable for sensing body iron levels.

Directory of Open Access Journals (Sweden)

Konstantinos Gkouvatsos

Full Text Available Hemojuvelin (Hjv is a bone morphogenetic protein (BMP co-receptor involved in the control of systemic iron homeostasis. Functional inactivation of Hjv leads to severe iron overload in humans and mice due to marked suppression of the iron-regulatory hormone hepcidin. To investigate the role of Hjv in body iron sensing, Hjv-/- mice and isogenic wild type controls were placed on a moderately low, a standard or a high iron diet for four weeks. Hjv-/- mice developed systemic iron overload under all regimens. Transferrin (Tf was highly saturated regardless of the dietary iron content, while liver iron deposition was proportional to it. Hepcidin mRNA expression responded to fluctuations in dietary iron intake, despite the absence of Hjv. Nevertheless, iron-dependent upregulation of hepcidin was more than an order of magnitude lower compared to that seen in wild type controls. Likewise, iron signaling via the BMP/Smad pathway was preserved but substantially attenuated. These findings suggest that Hjv is not required for sensing of body iron levels and merely functions as an enhancer for iron signaling to hepcidin.

Prediction of modified Mercalli intensity from PGA, PGV, moment magnitude, and epicentral distance using several nonlinear statistical algorithms

Science.gov (United States)

Alvarez, Diego A.; Hurtado, Jorge E.; Bedoya-Ruíz, Daniel Alveiro

2012-07-01

Despite technological advances in seismic instrumentation, the assessment of the intensity of an earthquake using an observational scale as given, for example, by the modified Mercalli intensity scale is highly useful for practical purposes. In order to link the qualitative numbers extracted from the acceleration record of an earthquake and other instrumental data such as peak ground velocity, epicentral distance, and moment magnitude on the one hand and the modified Mercalli intensity scale on the other, simple statistical regression has been generally employed. In this paper, we will employ three methods of nonlinear regression, namely support vector regression, multilayer perceptrons, and genetic programming in order to find a functional dependence between the instrumental records and the modified Mercalli intensity scale. The proposed methods predict the intensity of an earthquake while dealing with nonlinearity and the noise inherent to the data. The nonlinear regressions with good estimation results have been performed using the "Did You Feel It?" database of the US Geological Survey and the database of the Center for Engineering Strong Motion Data for the California region.

Structure and state of repeatedly rubbed pure iron

Energy Technology Data Exchange (ETDEWEB)

Furuichi, Hiroshi [Dept. of Mechanical System Engineering, Yamanashi Univ., Kofu (Japan); Nakamura, Shoichiro [Dept. of Mechanical System Engineering, Yamanashi Univ., Kofu (Japan); Xuan Junsong [Nippo Precision Ltd., Nirasaki (Japan); Yamazaki, Kunihiro [Dept. of Mechanical System Engineering, Yamanashi Univ., Kofu (Japan)

1995-05-01

Pure iron was repeatedly rubbed under special conditions. The highest and the average hardness near the friction surface were 1431 HV and 1146 HV, respectively. Diffraction patterns near the friction surface showed a broad hexagonal ring corresponding to the (002) plane of {epsilon}-iron (hcp), although the other rings are from {alpha}-iron. Extremely fine imperfectly defined regions were observed from the area of this diffraction pattern. Another diffraction patterns showed an extremely diffuse and faint halo ring indicating an amorphous state, whose average atomic distance equals one of the interplanar spacing of the basal plane of {epsilon}-iron. This amorphous state differs from that by obtained rapid quenching. These results suggest that a structure with only the basal plane of {epsilon}-iron appeared during the rubbing and further destruction resulted in the amorphous state. Extremely high pressure may arise during rubbing: {epsilon}-iron forms above 13 GPa at room temperature and the basal plane consists of the shortest atomic distance of iron. In the latter pattern, a spot arrangement indicating a structure ordered only in one or two directions was observed. Rows of pits and cracks connecting them were observed, on the side surface near the rubbed surface, which shows crack formation during sliding contact fatigue. (orig.)

Reversible uptake of molecular oxygen by heteroligand Co(II)-L-α-amino acid-imidazole systems: equilibrium models at full mass balance.

Science.gov (United States)

Pająk, Marek; Woźniczka, Magdalena; Vogt, Andrzej; Kufelnicki, Aleksander

2017-09-19

The paper examines Co(II)-amino acid-imidazole systems (where amino acid = L-α-amino acid: alanine, asparagine, histidine) which, when in aqueous solutions, activate and reversibly take up dioxygen, while maintaining the structural scheme of the heme group (imidazole as axial ligand and O 2 uptake at the sixth, trans position) thus imitating natural respiratory pigments such as myoglobin and hemoglobin. The oxygenated reaction shows higher reversibility than for Co(II)-amac systems with analogous amino acids without imidazole. Unlike previous investigations of the heteroligand Co(II)-amino acid-imidazole systems, the present study accurately calculates all equilibrium forms present in solution and determines the [Formula: see text]equilibrium constants without using any simplified approximations. The equilibrium concentrations of Co(II), amino acid, imidazole and the formed complex species were calculated using constant data obtained for analogous systems under oxygen-free conditions. Pehametric and volumetric (oxygenation) studies allowed the stoichiometry of O 2 uptake reaction and coordination mode of the central ion in the forming oxygen adduct to be determined. The values of dioxygen uptake equilibrium constants [Formula: see text] were evaluated by applying the full mass balance equations. Investigations of oxygenation of the Co(II)-amino acid-imidazole systems indicated that dioxygen uptake proceeds along with a rise in pH to 9-10. The percentage of reversibility noted after acidification of the solution to the initial pH ranged within ca 30-60% for alanine, 40-70% for asparagine and 50-90% for histidine, with a rising tendency along with the increasing share of amino acid in the Co(II): amino acid: imidazole ratio. Calculations of the share of the free Co(II) ion as well as of the particular complex species existing in solution beside the oxygen adduct (regarding dioxygen bound both reversibly and irreversibly) indicated quite significant values for the

Investigation of the Linker Swing Motion in the Zeolitic Imidazolate Framework ZIF-90

KAUST Repository

Zheng, Bin; Fu, Fang; Wang, Lian Li; Yang, Limin; Zhu, Yihan; Du, Huiling

2018-01-01

The linker swing motion in the zeolitic imidazolate framework ZIF-90 is investigated by density functional theory (DFT) calculation, molecular dynamics (MD) and grand-canonical Monte Carlo (GCMC) simulations. The relation between the terminal

Colour-magnitude diagram of NGC 5053

Energy Technology Data Exchange (ETDEWEB)

Walker, M F; Pike, C D [California Univ., Santa Cruz (USA). Lick Observatory; McGee, J D

1976-06-01

The colour-magnitude diagram of NGC 5053 has been derived to V = 21.1 from photographic and electronographic observations. The electronographic observations were obtained with an experimental Spectracon image-converter, having photocathode and exit window dimensions of 20 x 30 mm, mounted at the prime-focus of the 120-in. Lick reflector. The photographic observations were obtained with the 20-in. Carnegie astrograph and the 36-in. Crossley reflector. The colour-magnitude diagram resembles that of M92, with the difference that a red horizontal branch is more pronounced than the asymptotic branch in NGC 5053. The topology of the horizontal branch is that of clusters with an intermediate metal content and is thus at variance with the mean period of the RR Lyr stars and the unreddened colour of the subgiant branch read at the magnitude level of the horizontal branch, both of which would indicate an extremely low metal content. If comparison of the colour-magnitude diagrams of NGC 5053 and M92 is valid, then the reddening of NGC 5053 is Esub(B-V) = 0.02 and the apparent distance modulus is m-M = 16.08 +- 0.08.

γ-Alumina Nanoparticle Catalyzed Efficient Synthesis of Highly Substituted Imidazoles

Directory of Open Access Journals (Sweden)

Bandapalli Palakshi Reddy

2015-10-01

Full Text Available γ-Alumina nano particle catalyzed multi component reaction of benzil, arylaldehyde and aryl amines afforded the highly substituted 1,2,4,5-tetraaryl imidazoles with good to excellent yield in less reaction time under the sonication as well as the conventional methods. Convenient operational simplicity, mild conditions and the reusability of catalyst were the other advantages of this developed protocol.

Photoinduced Processes in Hydrogen Bonded System: Photodissociation of Imidazole Clusters

Czech Academy of Sciences Publication Activity Database

Poterya, Viktoriya; Profant, V.; Fárník, Michal; Šištík, L.; Slavíček, P.; Buck, U.

2009-01-01

Roč. 113, č. 52 (2009), s. 14583-14590 ISSN 1089-5639 R&D Projects: GA AV ČR KAN400400651; GA AV ČR KJB400400902; GA ČR GA203/09/0422 Institutional research plan: CEZ:AV0Z40400503 Keywords : scattering analysis * molecules * imidazole clusters Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.899, year: 2009

Efficacy of iron fortification compared to iron supplementation among Vietnamese schoolchildren

Directory of Open Access Journals (Sweden)

Nguyen Khan

2006-12-01

Full Text Available Abstract The effect of iron fortification is generally assumed to be less than iron supplementation; however, the magnitude of difference in effects is not known. The present study aims to compare the efficacy of these two strategies on anaemia and iron status. After screening on low Hb, 425 anaemic children in six primary schools in Tam Nong district of Phu Tho province were included in a randomized, placebo-controlled trial comparing two groups receiving iron fortified instant noodles or iron supplementation for 6 months and a control group, with children in all groups having been dewormed. Blood samples were collected before and after intervention for haemoglobin, serum ferritin (SF, serum transferrin receptor (TfR, C-reactive protein (CRP, and haemoglobinopathies analysis. Regression analysis was used to assess the effect of iron fortification and iron supplementation on haemoglobin concentration, SF, TfR, body iron, and anaemic status as outcome variables. The improvement of haemoglobin, SF, and body iron level in the group receiving iron fortification was 42% (2.6 g/L versus 6.2 g/L, 20% (23.5 μg/L versus 117.3 μg/L, and 31.3% (1.4 mg/kg versus 4.4 mg/kg of that in the iron supplementation group. The prevalence of anaemia dropped to 15.1% in the control group, with an additional reduction of anaemia of 8.5% in the iron supplementation group. The additional reduction due to iron fortification was 5.4%, which amounts to well over 50% of the impact of supplementation. In conclusion, the efficacy of iron fortification based on reduction of prevalence of anaemia, and on the change in haemoglobin level, is about half of the maximum impact of supplementation in case of optimal compliance. Thus, in a population of anaemic children with mild iron deficiency, iron fortification should be the preferred strategy to combat anaemia.

Coordination compounds of metals with imidazoles and benzimidazoles. [Metals: V, Th, Mo, Cd, rare earths, etc

Energy Technology Data Exchange (ETDEWEB)

Novikova, G A; Molodkin, A K; Kukalenko, S S

1988-12-01

Methods of preparation, composition and structure of UO/sub 2//sup 2+/, Th/sup 4+/, Mo/sup 3+/, Cd/sup 2+/, Ln/sup 3+/ metal ion complexes with imidazoles and benzimidazoles are considered in reviews of native and foreign literature of up to 1985. Complexes are customarily prepared by direct interaction of ligands with inorganic salts in different organic solvents. Complex composition is defined by the nature of complexing metal and inorganic salt anion, ligand volume and basicity, as well as solvent characteristics. Effect of R substituent in imidazole and benzimidazole side chain on composition of coordination compounds is considered.

Efficient library synthesis of imidazoles using a multicomponent reaction and microwave irradiation

NARCIS (Netherlands)

Gelens, E.; De Kanter, F.J.J.; Schmitz, R.F.; Sliedregt, L.A.; Van Steen, B.J.; Kruse, C.G.; Leurs, R.; Groen, M.B.; Orru, R.V.A.

2006-01-01

Optimization of Radziszewski's four-component reaction employing a microwave-assisted protocol, led to a small library of 48 imidazoles with a success rate of 65% (conversion >45%). All three diversity points of the four-component reaction were varied. Aromatic and aliphatic inputs were successfully

Earthquake Magnitude Relationships for the Saint Peter and Saint Paul Archipelago, Equatorial Atlantic

Science.gov (United States)

de Melo, Guilherme W. S.; do Nascimento, Aderson F.

2018-03-01

We have investigated several relationships between ML, M(NEIC) and Mw for the earthquakes locally recorded in the Saint Peter and Saint Paul Archipelago (SPSPA), Equatorial Atlantic. Because we only have one station in the area, we could not derive attenuation relations for events recorded at different distances at different stations. Our approach was then to compare our ML estimates with magnitudes reported by NEIC. This approach produced acceptable results particularly for epicentral distance smaller than 100 km. For distances greater that 100 km, there is a systematic increase in the residuals probable due to the lack of station correction and our inability to accurately estimate Q. We also investigate the Mw—M(NEIC) relationship. We find that Mw estimates using S-wave produce smaller residuals when compared with both M(NEIC). Finally, we also investigate the ML—Mw relationship and observe that given the data set we have, the 1:1 holds. We believe that the use of the present methodologies provide consistent magnitude estimates between all the magnitudes investigated that could be used to better assess seismic hazard in the region.

cis-Tetrachloridobis(1H-imidazole-κN3platinum(IV

Directory of Open Access Journals (Sweden)

Vadim Yu. Kukushkin

2012-05-01

Full Text Available In the title complex, cis-[PtCl4(C3H4N22], the PtIV ion lies on a twofold rotation axis and is coordinated in a slightly distorted octahedral geometry. The dihedral angle between the imidazole rings is 69.9 (2°. In the crystal, molecules are linked by N—H...Cl hydrogen bonds, forming a three-dimensional network.

Magnitude Estimation for Large Earthquakes from Borehole Recordings

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Eshaghi, A.; Tiampo, K. F.; Ghofrani, H.; Atkinson, G.

2012-12-01

We present a simple and fast method for magnitude determination technique for earthquake and tsunami early warning systems based on strong ground motion prediction equations (GMPEs) in Japan. This method incorporates borehole strong motion records provided by the Kiban Kyoshin network (KiK-net) stations. We analyzed strong ground motion data from large magnitude earthquakes (5.0 ≤ M ≤ 8.1) with focal depths < 50 km and epicentral distances of up to 400 km from 1996 to 2010. Using both peak ground acceleration (PGA) and peak ground velocity (PGV) we derived GMPEs in Japan. These GMPEs are used as the basis for regional magnitude determination. Predicted magnitudes from PGA values (Mpga) and predicted magnitudes from PGV values (Mpgv) were defined. Mpga and Mpgv strongly correlate with the moment magnitude of the event, provided sufficient records for each event are available. The results show that Mpgv has a smaller standard deviation in comparison to Mpga when compared with the estimated magnitudes and provides a more accurate early assessment of earthquake magnitude. We test this new method to estimate the magnitude of the 2011 Tohoku earthquake and we present the results of this estimation. PGA and PGV from borehole recordings allow us to estimate the magnitude of this event 156 s and 105 s after the earthquake onset, respectively. We demonstrate that the incorporation of borehole strong ground-motion records immediately available after the occurrence of large earthquakes significantly increases the accuracy of earthquake magnitude estimation and the associated improvement in earthquake and tsunami early warning systems performance. Moment magnitude versus predicted magnitude (Mpga and Mpgv).

Understanding reactivity of two newly synthetized imidazole derivatives by spectroscopic characterization and computational study

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Hossain, Mossaraf; Thomas, Renjith; Mary, Y. Sheena; Resmi, K. S.; Armaković, Stevan; Armaković, Sanja J.; Nanda, Ashis Kumar; Vijayakumar, G.; Van Alsenoy, C.

2018-04-01

Two newly synthetized imidazole derivatives (1-(4-methoxyphenyl)-4,5-dimethyl-1H-imidazole-2-yl acetate (MPDIA) and 1-(4-bromophenyl)-4,5-dimethyl-1H-imidazole-2-yl acetate (BPDIA)) have been prepared by solvent-free synthesis pathway and their specific spectroscopic and reactive properties have been discussed based on combined experimental and computational approaches. Aside of synthesis, experimental part of this work included measurements of IR, FT-Raman and NMR spectra. All of the aforementioned spectra were also obtained computationally, within the framework of density functional theory (DFT) approach. Additionally, DFT calculations have been used in order to investigate local reactivity properties based on molecular orbital theory, molecular electrostatic potential (MEP), average local ionization energy (ALIE), Fukui functions and bond dissociation energy (BDE). Molecular dynamics (MD) simulations have been used in order to obtain radial distribution functions (RDF), which were used for identification of the atoms with pronounced interactions with water molecules. MEP showed negative regions are mainly localized over N28, O29, O35 atoms, it is represent with red colour in rainbow color scheme for MPDIA and BPDIA (which are most reactive sites for electrophilic attack). The first order hyperpolarizabilities of MPDIA and BPDIA are 20.15 and 6.10 times that of the standard NLO material urea. Potential interaction with antihypertensive protein hydrolase.

Automated Determination of Magnitude and Source Length of Large Earthquakes

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Wang, D.; Kawakatsu, H.; Zhuang, J.; Mori, J. J.; Maeda, T.; Tsuruoka, H.; Zhao, X.

2017-12-01

Rapid determination of earthquake magnitude is of importance for estimating shaking damages, and tsunami hazards. However, due to the complexity of source process, accurately estimating magnitude for great earthquakes in minutes after origin time is still a challenge. Mw is an accurate estimate for large earthquakes. However, calculating Mw requires the whole wave trains including P, S, and surface phases, which takes tens of minutes to reach stations at tele-seismic distances. To speed up the calculation, methods using W phase and body wave are developed for fast estimating earthquake sizes. Besides these methods that involve Green's Functions and inversions, there are other approaches that use empirically simulated relations to estimate earthquake magnitudes, usually for large earthquakes. The nature of simple implementation and straightforward calculation made these approaches widely applied at many institutions such as the Pacific Tsunami Warning Center, the Japan Meteorological Agency, and the USGS. Here we developed an approach that was originated from Hara [2007], estimating magnitude by considering P-wave displacement and source duration. We introduced a back-projection technique [Wang et al., 2016] instead to estimate source duration using array data from a high-sensitive seismograph network (Hi-net). The introduction of back-projection improves the method in two ways. Firstly, the source duration could be accurately determined by seismic array. Secondly, the results can be more rapidly calculated, and data derived from farther stations are not required. We purpose to develop an automated system for determining fast and reliable source information of large shallow seismic events based on real time data of a dense regional array and global data, for earthquakes that occur at distance of roughly 30°- 85° from the array center. This system can offer fast and robust estimates of magnitudes and rupture extensions of large earthquakes in 6 to 13 min (plus

Construction, Structural Diversity and Properties of Five Coordination Polymers Based on 5-Nitroisophthalate and Bis(imidazole) Linkers

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Arıcı, Mürsel

2018-06-01

Five coordination polymers, namely, [Cd(μ3-5-nip)(μ-obix)]n (1), [Co(μ3-5-nip)(μ-obix)]n (2), [Zn(μ-5-nip)(μ-obix)]n (3 and 4) and [Cd(μ-5-nip)(μ-bisobix)]n (5) (5-nip: 5-nitroisophthalate, obix: 1,2-bis(imidazol-1ylmethyl)benzene, bisobix: 1,2-bis(2-isopropylimidazol-1ylmethyl)benzene) were hydrothermally synthesized and characterized by IR spectroscopy, elemental analysis, single crystal and powder X-ray diffraction and thermal analysis (TG/DTA). X-ray results showed that the complexes displayed structural diversity depending on metal ions and conformations of bis(imidazole) linkers. Complexes 1 and 2 were 1D structures and obix ligand displayed cis-conformation. Complexes 3 and 4 exhibited 2D and 3D structures with same components depending on obix conformation. In complex 5, 3D+3D→3D interpenetrated structure was obtained with dia topology when bisobix having sterically hindered groups on imidazole rings was used. Moreover, thermal, photoluminescence and optical properties of the complexes were also investigated.

Spectral, biological screening of metal chelates of chalcone based Schiff bases of N-(3-aminopropyl) imidazole.

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Kalanithi, M; Rajarajan, M; Tharmaraj, P; Sheela, C D

2012-02-15

Tridentate chelate complexes of Co(II), Ni(II), Cu(II) and Zn(II) have been synthesized from the chalcone based ligands 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-(phenylallyl)]phenol(HL(1)), 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-p-tolylallyl]phenol(HL(2)), 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-4-nitrophenylallyl]phenol(HL(3)). Microanalytical data, UV-vis spectrophotometric method, magnetic susceptibility measurements, IR, 1H NMR, Mass, and EPR techniques were used to characterize the structure of chelates. The electronic absorption spectra and magnetic susceptibility measurements suggest a distorted square planar geometry for the copper(II) ion. The other metal complexes show distorted tetrahedral geometry. The coordination of the ligands with metal(II) ions was further confirmed by solution fluorescence spectrum. The antimicrobial activity of the ligands and metal(II) complexes against the species Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albigans and Aspergillus niger has been carried out and compared. The electrochemical behavior of copper(II) complex is studied by cyclic voltammetry. Copyright © 2011 Elsevier B.V. All rights reserved.

Moment Magnitude Determination for Marmara Region-Turkey Using Displacement Spectra

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Köseoǧlu Küsmezer, Ayşegül; Meral Özel, Nurcan; Barış, Å.žErif; Üçer, S. Balamir; Ottemöller, Lars

2010-05-01

The main purpose of the study is to determine moment magnitude Mω using displacement source spectra of earthquakes occurred in Marmara Region. The region is the most densely populated and fast-developing part of Turkey, bounded by 39.0°N to 42.0°N and 26.0°E to 32.0°E, and have experienced major earthquake disasters during the last four centuries with destructive earthquakes and probabilistic seismic hazard studies shows that the region have significant probability of producing M>7 earthquake within the next years. Seismic moment is a direct measurement of earthquake size (rupture area and static displacement) and does not saturate, spectral analysis at local distances is a very useful method which allows the reliable determination of seismic moment and moment magnitude. We have used converging grid search method developed by L. Ottemöller, and J. Havskov, 2008 for the automatic determination of moment magnitude for local distances. For data preperation; the time domain signal of S waves were extracted from the vertical component seismograms.Data was transformed from time to frequency domain by applying the standart fast fourier transform (fft). Source parameters and moment magnitudes of earthquakes are determined by applying spectral fitting procedure to classical Brune's model. The method is first manually and then automatically performed on the source spectrum of S waves within 20 sec. Mo and fc (Aki;1967, and Brune;1970) were determined by using the method which the model space is divided into a grid and the error function detected for all grid points. A smaller grid with denser spacing around the best solution is generated with an iterative procedure. The moment magnitudes of the earthquakes have been calculated according to the scale of Kanamori (1977) and Hanks and Kanamori (1979). A data set of 279 events recorded on broadband velocity seismograms extracted from KOERI (Kandilli Observatory and Earthquake Research Institute) seismic network were

Toward understanding macrocycle specificity of iron on the dioxygen-binding ability: a theoretical study.

Science.gov (United States)

Sun, Yong; Chen, Kexian; Jia, Lu; Li, Haoran

2011-08-14

In an effort to examine the interaction between dioxygen and iron-macrocyclic complexes, and to understand how this interaction was affected by those different macrocyclic ligands, dioxygen binding with iron-porphyrin, iron-phthalocyanine, iron-dibenzotetraaza[14]annulene, and iron-salen complexes is investigated by means of quantum chemical calculations utilizing Density Functional Theory (DFT). Based on the analysis of factors influencing the corresponding dioxygen binding process, it showed that different macrocyclic ligands possess different O-O bond distances, and different electronic configurations for the bound O(2) and non-aromatic macrocyclic ligands favor dioxygen activation. Furthermore, the smaller the energy gap between the HOMO of iron-macrocyclic complexes and the LUMO of dioxygen, the more active the bound O(2) becomes, with a longer O-O bond distance and a shorter Fe-O bond length.

New moment magnitude scale, evidence of stress drop magnitude scaling and stochastic ground motion model for the French West Indies

Science.gov (United States)

Drouet, Stéphane; Bouin, Marie-Paule; Cotton, Fabrice

2011-12-01

In this study we analyse records from the 'Les Saintes' seismic sequence following the Mw= 6.3 earthquake of 2004 November 11, which occurred close to Guadeloupe (French West Indies). 485 earthquakes with magnitudes from 2 to 6, recorded at distances between 5 and 150 km are used. S-waves Fourier spectra are analysed to simultaneously determine source, path and site terms. The results show that the duration magnitude routinely estimated for the events that occurred in the region underestimate moment magnitude by 0.5 magnitude units over the whole magnitude range. From the inverted seismic moments and corner frequencies, we compute Brune's stress drops. We show that stress drops increase with increasing magnitude. The same pattern is observed on apparent stresses (i.e. the seismic energy-to-moment ratio). However, the rate of increase diminishes at high magnitudes, which is consistent with a constant stress drop model for large events. Using the results of the inversions, we perform ground motion simulations for the entire data set using the SMSIM stochastic simulation tool. The results show that a good fit (σ= 0.25) with observed data is achieved when the source is properly described by its moment magnitude and stress drop, and when site effects are taken into account. Although the magnitude-dependent stress drop model is giving better results than the constant stress drop model, the interevent variability remains high, which could suggest that stress drop depends on other parameters such as the depth of the hypocentre. In any case, the overall variability is of the same order of magnitude as usually observed in empirical ground motion prediction equations.

Diffusion of iron in β-iron telluride (Fe1.12Te) by Moessbauer spectroscopy and tracer method

International Nuclear Information System (INIS)

Magara, Masaaki; Tsuji, Toshihide; Naito, Keiji

1993-01-01

The diffusion coefficient of iron in a β-iron telluride (Fe 1.12 Te) polycrystalline sample was measured by Moessbauer diffusional line broadening method which relates to the collapse of coherence in gamma-ray photon by the atomic jump at local sites. The diffusion coefficient of iron along the c-axis in nearly single crystal of β-iron telluride was also measured by tracer technique which shows the results of an atom transport in long distance. The activation energies for the diffusion of iron in Fe 1.12 Te obtained by the Moessbauer spectroscopy and the tracer method were 91.5±5.4 and 106±23 kJ/mol, respectively. The diffusion coefficients of iron in β-iron telluride obtained by Moessbauer line broadening are in fair agreement with the values averaged from that along c-axis obtained by tracer method and that along a- and b-axes obtained from reaction rate constant between iron and tellurium by the previous study of the present authors. (orig.)

The colour-magnitude diagram of NGC 5053

International Nuclear Information System (INIS)

Walker, M.F.; Pike, C.D.; McGee, J.D.

1976-01-01

The colour-magnitude diagram of NGC 5053 has been derived to V = 21.1 from photographic and electronographic observations. The electronographic observations were obtained with an experimental Spectracon image-converter, having photocathode and exit window dimensions of 20 x 30 mm, mounted at the prime-focus of the 120-in. Lick reflector. The photographic observations were obtained with the 20-in. Carnegie astrograph and the 36-in. Crossley reflector. The colour-magnitude diagram resembles that of M92, with the difference that a red horizontal branch is more pronounced than the asymptotic branch in NGC 5053. The topology of the horizontal branch is that of clusters with an intermediate metal content and is thus at variance with the mean period of the RR Lyr stars and the unreddened colour of the subgiant branch read at the magnitude level of the horizontal branch, both of which would indicate an extremely low metal content. If comparison of the colour-magnitude diagrams of NGC 5053 and M92 is valid, then the reddening of NGC 5053 is Esub(B-V) = 0.02 and the apparent distance modulus is m-M = 16.08 +- 0.08. (author)

Metal-containing Complexes of Lactams, Imidazoles, and Benzimidazoles and Their Biological Activity

Science.gov (United States)

Kukalenko, S. S.; Bovykin, B. A.; Shestakova, S. I.; Omel'chenko, A. M.

1985-07-01

The results of the latest investigations of the problem of the synthesis of metal-containing complexes of lactams, imidazoles, and benzimidazoles, their structure, and their stability in solutions are surveyed. Some data on their biological activity (pesticide and pharmacological) and the mechanism of their physiological action are presented. The bibliography includes 190 references.

Natural resources sustainability: iron ore mining

International Nuclear Information System (INIS)

De La Torre de Palacios, Luis

2011-01-01

In the present article, a new tool to determine environmental sustainability, the energy impact index (EII) was developed to classify different iron mine projects according to two main parameters including energy consumption and CO 2 emissions. The EII considers the characteristics of the mineral (such as the quality, size, hardness, iron ore grade, reducibility, mineral/waste rate, and type of deposit), mining processes (type of exploitation, ore processing, available technology), and transportation (distance to cover).

Oxidative Debromination and Degradation of Tetrabromo-bisphenol A by a Functionalized Silica-Supported Iron(III-tetrakis(p-sulfonatophenylporphyrin Catalyst

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Masami Fukushima

2013-05-01

Full Text Available Tetrabromobisphenol A (TBBPA, a commonly used brominated flame retardant, also functions as an endocrine disruptor. Thus, the degradation of TBBPA has attracted considerable interest among the scientific community. Iron(III-porphyrin complexes are generally regarded as “green” catalysts and have been reported to catalyze the efficient degradation and dehalogenation of halogenated phenols in environmental wastewaters. However, they are quickly deactivated due to self-degradation in the presence of an oxygen donor, such as KHSO5. In the present study, an iron(III-tetrakis (p-sulfonatophenyl-porphyrin (FeTPPS was immobilized on imidazole-modified silica (FeTPPS/IPS via coordination of the Fe(III with the nitrogen atom in imidazole to suppress self-degradation and thus enhance the catalyst reusability. The oxidative degradation and debromination of TBBPA and the influence of humic acid (HA, a major component in leachates, on the oxidation of TBBPA was investigated. More than 95% of the TBBPA was degraded in the pH range from 3 to 8 in the absence of HA, while the optimal pH for the reaction was at pH 8 in the presence of HA. Although the rate of degradation was decreased in the presence of HA, over 95% of the TBBPA was degraded within 12 h in the presence of 28 mg-C L−1 of HA. At pH 8, the FeTPPS/IPS catalyst could be reused up to 10 times without any detectable loss of activity for TBBPA for degradation and debromination, even in the presence of HA.

[Ferrous sulfate in the treatment of iron deficiency anemia: The positions continue].

Science.gov (United States)

Dvoretsky, L I

The paper discusses treatment strategy and tactics for iron deficiency anemia. It gives data on the comparative efficacy of different iron sulfate drugs, their bioavailability, effects on peroxidation processes, and side effects. The paper also considers the clinical significance of a dosage form of iron-containing drugs with a sustained iron release, as well as ways to reduce the frequency and magnitude of side effects when ferrous sulfate is used.

Imidazole as a pH Probe: An NMR Experiment for the General Chemistry Laboratory

Science.gov (United States)

Hagan, William J., Jr.; Edie, Dennis L.; Cooley, Linda B.

2007-01-01

The analysis describes an NMR experiment for the general chemistry laboratory, which employs an unknown imidazole solution to measure the pH values. The described mechanism can also be used for measuring the acidity within the isolated cells.

Antibacterial activity of synthesized 2,4,5-trisubstituted imidazole derivatives

Digital Repository Service at National Institute of Oceanography (India)

Khan, M.S.; Siddiqui, S.A.; Siddiqui, M.S.R.A.; Goswami, U.; Srinivasan, K.V.; Khan, M.I.

release or inhibiting the p38 MAP kinase (1), anti-allergic activity (2) and analgesic activity (3). They are also sensitizers of multidrug-resistant cancer cells (4), pesticides (5), antibiotics (6) or sodium-channel mod- ulators (7). Some imidazole... (ATCC 25922), Klebsiella pneumoniae (ATCC 13883), Pseudomonas aeruginosa (ATCC 27853) and Serratia morganii (ATCC 31665), obtained from Goa Medical college, Goa, India, grown to mid-logarithmic phase were harvested by centrifu- gation, washed with 10 m...

Synthesis and Antibacterial Activities of New Metronidazole and Imidazole Derivatives

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Abdul Jabar Kh. Atia

2009-07-01

Full Text Available New imidazole ring derivatives comprising 1,3-oxazoline, Schiff's bases, thiadiazole, oxadiazole and 1,2,4-triazole moieties are reported. 3-Aminobiimidazol-4-one compounds 7a-c were synthesized by the reaction of compounds 6a-c with hydrazine hydrate. Biimidazole esters 9a-c were converted into biimidazole hydrazide esters 10a-c. Compounds 7a-c and 10a-c were converted into a variety of derivatives.

High-performance polyamide thin-film-nanocomposite reverse osmosis membranes containing hydrophobic zeolitic imidazolate framework-8

KAUST Repository

Duan, Jintang; Pan, Yichang; Pacheco Oreamuno, Federico; Litwiller, Eric; Lai, Zhiping; Pinnau, Ingo

2015-01-01

A hydrophobic, hydrothermally stable metal-organic framework (MOF) - zeolitic imidazolate framework-8 (ZIF-8) was successfully incorporated into the selective polyamide (PA) layer of thin-film nanocomposite (TFN) membranes for water desalination

Diffusion of hydrogen in iron oxides

International Nuclear Information System (INIS)

Bruzzoni, P.

1993-01-01

The diffusion of hydrogen in transitions metals oxides has been recently studied at room temperature through the permeability electrochemical technique. This work studies thin oxide layers grown in air or in presence of oxidizing atmospheres at temperatures up to 200 deg C. The substrate was pure iron with different superficial treatments. It was observed that these oxides reduce up to three magnitudes orders, the hydrogen stationary flux through membranes of usual thickness in comparison with iron membranes free of oxide. (Author)

Mitochondria Targeted Nanoscale Zeolitic Imidazole Framework-90 for ATP Imaging in Live Cells.

Science.gov (United States)

Deng, Jingjing; Wang, Kai; Wang, Ming; Yu, Ping; Mao, Lanqun

2017-04-26

Zeolitic imidazole frameworks (ZIFs) are an emerging class of functional porous materials with promising biomedical applications such as molecular sensing and intracellular drug delivery. We report herein the first example of using nanoscale ZIFs (i.e., ZIF-90), self-assembled from Zn 2+ and imidazole-2-carboxyaldehyde, to target subcellular mitochondria and image dynamics of mitochondrial ATP in live cells. Encapsulation of fluorescent Rhodamine B (RhB) into ZIF-90 suppresses the emission of RhB, while the competitive coordination between ATP and the metal node of ZIF-90 dissembles ZIFs, resulting in the release of RhB for ATP sensing. With this method, we are able to image mitochondrial ATP in live cells and study the ATP level fluctuation in cellular glycolysis and apoptosis processes. The strategy reported here could be further extended to tune nanoscale ZIFs inside live cells for targeted delivery of therapeutics to subcellular organelles for advanced biomedical applications.

Synthesis, spectroscopic, computational (DFT/B3LYP), AChE inhibition and antioxidant studies of imidazole derivative

Science.gov (United States)

Ahmad, Faheem; Alam, Mohammad Jane; Alam, Mahboob; Azaz, Shaista; Parveen, Mehtab; Park, Soonheum; Ahmad, Shabbir

2018-01-01

The present study reports the synthesis and evaluation of biological properties of 3a,8a-dihydroxy-8-oxo-1,3,3a,8a-tetrahydroindeno[1,2-d]imidazol-2(1H)-iminium chloride (3). The structure was confirmed by the FTIR, NMR, MS, CHN microanalysis and X-ray crystallographic analysis. Quantum chemical calculations have been performed at B3LYP-D3/6-311++G(d,p) level of theory to study the molecular geometry, IR, (1H and 13C) NMR, UV/Vis spectra and other molecular parameters of the asymmetric unit of crystal of imidazole compound (3). An empirical dispersion correction to hybrid functional (B3LYP-D3) has been incorporated in the present calculations due to presence of non-covalent interaction, Cl⋯H-O, in the present compound. The remarkable agreement has been observed between theoretical data and those measured experimentally. Moreover, the Hirshfeld analysis was carried out to ascertain the secondary interactions and associated 2D fingerprint plots. The synthesized imidazole derivative showed promising antioxidant property and inhibitory activity against acetylcholinesterase (AChE). Molecular docking was also performed in order to explain in silico antioxidant studies and to ascertain the probable binding mode of compound with the amino acid residues of protein.

Nanoparticulate iron(III) oxo-hydroxide delivers safe iron that is well absorbed and utilised in humans

Science.gov (United States)

Pereira, Dora I.A.; Bruggraber, Sylvaine F.A.; Faria, Nuno; Poots, Lynsey K.; Tagmount, Mani A.; Aslam, Mohamad F.; Frazer, David M.; Vulpe, Chris D.; Anderson, Gregory J.; Powell, Jonathan J.

2014-01-01

Iron deficiency is the most common nutritional disorder worldwide with substantial impact on health and economy. Current treatments predominantly rely on soluble iron which adversely affects the gastrointestinal tract. We have developed organic acid-modified Fe(III) oxo-hydroxide nanomaterials, here termed nano Fe(III), as alternative safe iron delivery agents. Nano Fe(III) absorption in humans correlated with serum iron increase (P solubility. The most promising preparation (iron hydroxide adipate tartrate: IHAT) showed ~80% relative bioavailability to Fe(II) sulfate in humans and, in a rodent model, IHAT was equivalent to Fe(II) sulfate at repleting haemoglobin. Furthermore, IHAT did not accumulate in the intestinal mucosa and, unlike Fe(II) sulfate, promoted a beneficial microbiota. In cellular models, IHAT was 14-fold less toxic than Fe(II) sulfate/ascorbate. Nano Fe(III) manifests minimal acute intestinal toxicity in cellular and murine models and shows efficacy at treating iron deficiency anaemia. From the Clinical Editor This paper reports the development of novel nano-Fe(III) formulations, with the goal of achieving a magnitude less intestinal toxicity and excellent bioavailability in the treatment of iron deficiency anemia. Out of the tested preparations, iron hydroxide adipate tartrate met the above criteria, and may become an important tool in addressing this common condition. PMID:24983890

Synthesis and characterization of new chiral ketopinic acid-derived catalysts immobilized on polystyrene-bound imidazole

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Hassan Yusuf

2017-02-01

Full Text Available Four new chiral ketopinic acid-derived catalysts were anchored on a polystyrene-bound imidazole via non-covalent bond. The resulting heterogeneous catalysts were successfully characterized using IR, SEM, and TGA analyses.

Magnetic graphene oxide modified by imidazole-based ionic liquids for the magnetic-based solid-phase extraction of polysaccharides from brown alga.

Science.gov (United States)

Wang, Xiaoqin; Li, Guizhen; Row, Kyung Ho

2017-08-01

Magnetic graphene oxide was modified by four imidazole-based ionic liquids to synthesize materials for the extraction of polysaccharides by magnetic solid-phase extraction. Fucoidan and laminarin were chosen as the representative polysaccharides owing to their excellent pharmaceutical value and availability. Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, and thermogravimetric analysis were applied to characterize the synthesized materials. Single-factor experiments showed that the extraction efficiency of polysaccharides was affected by the amount of ionic liquids for modification, solid-liquid ratio of brown alga and ethanol, the stirring time of brown alga and ionic liquid-modified magnetic graphene oxide materials, and amount of 1-(3-aminopropyl)imidazole chloride modified magnetic graphene oxide materials added to the brown alga sample solution. The results indicated that 1-(3-aminopropyl)imidazole chloride modified magnetic graphene oxide possessed better extraction ability than graphene oxide, magnetic graphene oxide, and other three ionic-liquid-modified magnetic graphene oxide materials. The highest extraction recoveries of fucoidan and laminarin extracted by 1-(3-aminopropyl)imidazole chloride modified magnetic graphene oxide were 93.3 and 87.2%, respectively. In addition, solid materials could be separated and reused easily owing to their magnetic properties. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sequential one-pot synthesis of imidazoles and 2H-imidazolones from β-ketoamines, acylating agents and ammonium acetate

Energy Technology Data Exchange (ETDEWEB)

Jalani, Hitesh B.; Venkateswararao, Edda; Manickam, Manoj; Jung, Sang Hun [College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, Daejeon (Korea, Republic of)

2016-12-15

An efficient, practical, straight forward, and transition metal-free three-component synthesis of diversely substituted imidazoles and 2H-imidazolones from β-ketoamines, acylating agents, and ammonium acetate has been described herein. This approach involves [3+1+1] cyclization through consecutive formation of three C–N bonds as a sequence of initial amidation of β-ketoamines with acylating agent, β-iminoketoamide formation with ammonia, and acid catalyzed concomitant cyclodehydration to afford the imidazoles and 2H-imidazolones. This methodology has advantages such as single flask operation, readily available starting materials, mild conditions, broad functional groups tolerance, and simple work-up procedure.

The Effects of Dietary Fat and Iron Interaction on Brain Regional Iron Contents and Stereotypical Behaviors in Male C57BL/6J Mice

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Lumei Liu

2016-07-01

Full Text Available Adequate brain iron levels are essential for enzyme activities, myelination, and neurotransmitter synthesis in the brain. Although systemic iron deficiency has been found in genetically or dietary-induced obese subjects, the effects of obesity-associated iron dysregulation in brain regions have not been examined. The objective of this study was to examine the effect of dietary fat and iron interaction on brain regional iron contents and regional-associated behavior patterns in a mouse model. Thirty C57BL/6J male weanling mice were randomly assigned to six dietary treatment groups (n=5 with varying fat (control/high and iron (control/high/low contents. The stereotypical behaviors were measured during the 24th week. Blood, liver, and brain tissues were collected at the end of the 24th week. Brains were dissected into the hippocampus, midbrain, striatum, and thalamus regions. Iron contents and ferritin-H (FtH protein and mRNA expressions in these regions were measured. Correlations between stereotypical behaviors and brain regional iron contents were analyzed at the 5% significance level. Results showed that high-fat diet altered the stereotypical behaviors such as inactivity and total distance traveled (P<0.05. The high-fat diet altered brain iron contents and ferritin-H (FtH protein and mRNA expressions in a regional-specific manner: 1 high-fat diet significantly decreased the brain iron content in the striatum (P<0.05, but not other regions; and 2 thalamus has a more distinct change in FtH mRNA expression compared to other regions. Furthermore, high-fat diet resulted in a significant decreased total distance traveled and a significant correlation between iron content and sleeping in midbrain (P<0.05. Dietary iron also decreased brain iron content and FtH protein expression in a regionally specific manner. The effect of interaction between dietary fat and iron was observed in brain iron content and behaviors. All these findings will lay

Nitric oxide and iron modulate heme oxygenase activity as a long distance signaling response to salt stress in sunflower seedling cotyledons.

Science.gov (United States)

Singh, Neha; Bhatla, Satish C

2016-02-29

Nitric oxide is a significant component of iron signaling in plants. Heme is one of the iron sensors in plants. Free heme is highly toxic and can cause cell damage as it catalyzes the formation of reactive oxygen species (ROS). Its catabolism is carried out by heme oxygenase (HOs; EC 1.14.99.3) which uses heme both as a prosthetic group and as a substrate. Two significant events, which accompany adaptation to salt stress in sunflower seedlings, are accumulation of ROS and enhanced production of nitric oxide (NO) in roots and cotyledons. Present investigations on the immunolocalization of heme oxygenase distribution in sunflower seedling cotyledons by confocal laser scanning microscopic (CLSM) imaging provide new information on the differential spatial distribution of the inducible form of HO (HO-1) as a long distance in response to NaCl stress. The enzyme is abundantly distributed in the specialized cells around the secretory canals (SCs) in seedling cotyledons. Abundance of tyrosine nitrated proteins has also been observed in the specialized cells around the secretory canals in cotyledons derived from salt stressed seedlings. The spatial distribution of tyrosine nitrated proteins and HO-1 expression further correlates with the abundance of mitochondria in these cells. Present findings, thus, highlight a link among distribution of HO-1 expression, abundance of tyrosine nitrated proteins and mitochondria in specialized cells around the secretory canal as a long distance mechanism of salt stress tolerance in sunflower seedlings. Enhanced spatial distribution of HO-1 in response to NaCl stress in seedling cotyledons is in congruence with the observed increase in specific activity of HO-1 in NaCl stressed conditions. The enzyme activity is further enhanced by hemin (HO-1 inducer) both in the absence or presence of NaCl stress and inhibited by zinc protoporphyrin. Western blot analysis of cotyledon homogenates using anti-HO-1 polyclonal antibody shows one major band (29

Luminescent pH sensor of a novel imidazole-containing hexanuclear Ru(II) polypyridyl complex

Science.gov (United States)

Cheng, Feixiang; Tang, Ning; Chen, Jishu; Chen, Guang

2013-10-01

Hexapodal ligand H6L containing imidazole rings has been prepared by the reaction of 1,10-phenanthroline-5,6-dione with 1,2,3,4,5,6-hexakis[(3-formylphenoxy)methyl]benzene. The Ru(II) polypyridyl complex [{Ru(bpy)2}6(μ6-H6L)](PF6)12 (bpy = 2,2'-bipyridine) has been synthesized by the reaction of Ru(bpy)2Cl2·2H2O with ligand H6L. The pH effects on the UV-vis absorption and emission spectra of the complex have been studied. The ground- and excited-state ionization constants of the acid-base equilibria have been calculated according to the absorbance and emission data. The complex acts as an off-on-off luminescent pH sensor through two successive deprotonation processes of imidazole rings, with a maximum on-off ratio of 5 in buffer solution.

Symbolic and non-symbolic number magnitude processing in children with developmental dyscalculia.

Science.gov (United States)

Castro Cañizares, Danilka; Reigosa Crespo, Vivian; González Alemañy, Eduardo

2012-11-01

The aim of this study was to evaluate if children with Developmental Dyscalculia (DD) exhibit a general deficit in magnitude representations or a specific deficit in the connection of symbolic representations with the corresponding analogous magnitudes. DD was diagnosed using a timed arithmetic task. The experimental magnitude comparison tasks were presented in non-symbolic and symbolic formats. DD and typically developing (TD) children showed similar numerical distance and size congruity effects. However, DD children performed significantly slower in the symbolic task. These results are consistent with the access deficit hypothesis, according to which DD children's deficits are caused by difficulties accessing magnitude information from numerical symbols rather than in processing numerosities per se.

Elevated Serum Hepcidin Levels during an Intensified Training Period in Well-Trained Female Long-Distance Runners

Directory of Open Access Journals (Sweden)

Aya Ishibashi

2017-03-01

Full Text Available Iron is essential for providing oxygen to working muscles during exercise, and iron deficiency leads to decreased exercise capacity during endurance events. However, the mechanism of iron deficiency among endurance athletes remains unclear. In this study, we compared iron status between two periods involving different training regimens. Sixteen female long-distance runners participated. Over a seven-month period, fasting blood samples were collected during their regular training period (LOW; middle of February and during an intensified training period (INT; late of August to determine blood hematological, iron, and inflammatory parameters. Three-day food diaries were also assessed. Body weight and lean body mass did not differ significantly between LOW and INT, while body fat and body fat percentage were significantly lower in INT (p < 0.05. Blood hemoglobin, serum ferritin, total protein, and iron levels, total iron-binding capacity, and transferrin saturation did not differ significantly between the two periods. Serum hepcidin levels were significantly higher during INT than LOW (p < 0.05. Carbohydrate and iron intakes from the daily diet were significantly higher during INT than LOW (p < 0.05. In conclusion, an elevated hepcidin level was observed during an intensified training period in long-distance runners, despite an apparently adequate daily intake of iron.

Understanding the magnitude dependence of PGA and PGV in NGA-West 2 data

Science.gov (United States)

Baltay, Annemarie S.; Hanks, Thomas C.

2014-01-01

The Next Generation Attenuation‐West 2 (NGA‐West 2) 2014 ground‐motion prediction equations (GMPEs) model ground motions as a function of magnitude and distance, using empirically derived coefficients (e.g., Bozorgniaet al., 2014); as such, these GMPEs do not clearly employ earthquake source parameters beyond moment magnitude (M) and focal mechanism. To better understand the magnitude‐dependent trends in the GMPEs, we build a comprehensive earthquake source‐based model to explain the magnitude dependence of peak ground acceleration and peak ground velocity in the NGA‐West 2 ground‐motion databases and GMPEs. Our model employs existing models (Hanks and McGuire, 1981; Boore, 1983, 1986; Anderson and Hough, 1984) that incorporate a point‐source Brune model, including a constant stress drop and the high‐frequency attenuation parameter κ0, random vibration theory, and a finite‐fault assumption at the large magnitudes to describe the data from magnitudes 3 to 8. We partition this range into four different magnitude regions, each of which has different functional dependences on M. Use of the four magnitude partitions separately allows greater understanding of what happens in any one subrange, as well as the limiting conditions between the subranges. This model provides a remarkably good fit to the NGA data for magnitudes from 3distances (Rrup≤20  km). We explore the trade‐offs between Δσ and κ0 in ground‐motion models and data, which play an important role in understanding small‐magnitude data, for which the corner frequency is masked by the attenuation of high frequencies. That this simple, source‐based model matches the NGA‐West 2 GMPEs and data so well suggests that considerable simplicity underlies the parametrically complex NGA GMPEs.

Bromidotetra?kis?(2-isopropyl-1H-imidazole-?N 3)copper(II) bromide

OpenAIRE

Godlewska, Sylwia; Socha, Joanna; Baranowska, Katarzyna; Do??ga, Anna

2011-01-01

The CuII atom in the title salt, [CuBr(C6H10N2)4]Br, is coordinated in a square-pyramidal geometry by four imidazole N atoms and one bromide anion that is located at the apex of the pyramid. The cations and the anions form a two-dimensional network parallel to (001) through N—H...Br hydrogen bonds.

Crystal structure of 1-[2-(4-chlorophenyl-4,5-diphenyl-1H-imidazol-1-yl]propan-2-ol

Directory of Open Access Journals (Sweden)

Shaaban K. Mohamed

2017-01-01

Full Text Available The title compound, C24H21ClN2O, crystallizes with two unique molecules in the asymmetric unit. In each molecule, the central imidazole ring is substituted at the 2-, 4- and 5-positions by benzene rings. The 2-substituted ring carries a Cl atom at the 4-position. One of the imidazole N atoms in each molecule has a propan-2-ol substituent. In the crystal, a series of O—H...N, C—H...O and C—H...Cl hydrogen bonds, augmented by several C—H...π(ring interactions, generate a three-dimensional network of molecules stacked along the a-axis direction.

Mixed-linker zeolitic imidazolate framework mixed-matrix membranes for aggressive CO2 separation from natural gas

KAUST Repository

Thompson, Joshua A.; Vaughn, Justin T.; Brunelli, Nicholas A.; Koros, William J.; Jones, Christopher W.; Nair, Sankar

2014-01-01

Zeolitic imidazolate framework (ZIF) materials are a promising subclass of metal-organic frameworks (MOF) for gas separations. However, due to the deleterious effects of gate-opening phenomena associated with organic linker rotation near

Strong motion duration and earthquake magnitude relationships

International Nuclear Information System (INIS)

Salmon, M.W.; Short, S.A.; Kennedy, R.P.

1992-06-01

Earthquake duration is the total time of ground shaking from the arrival of seismic waves until the return to ambient conditions. Much of this time is at relatively low shaking levels which have little effect on seismic structural response and on earthquake damage potential. As a result, a parameter termed ''strong motion duration'' has been defined by a number of investigators to be used for the purpose of evaluating seismic response and assessing the potential for structural damage due to earthquakes. This report presents methods for determining strong motion duration and a time history envelope function appropriate for various evaluation purposes, for earthquake magnitude and distance, and for site soil properties. There are numerous definitions of strong motion duration. For most of these definitions, empirical studies have been completed which relate duration to earthquake magnitude and distance and to site soil properties. Each of these definitions recognizes that only the portion of an earthquake record which has sufficiently high acceleration amplitude, energy content, or some other parameters significantly affects seismic response. Studies have been performed which indicate that the portion of an earthquake record in which the power (average rate of energy input) is maximum correlates most closely with potential damage to stiff nuclear power plant structures. Hence, this report will concentrate on energy based strong motion duration definitions

Color-magnitude diagrams for six metal-rich, low-latitude globular clusters

Science.gov (United States)

Armandroff, Taft E.

1988-01-01

Colors and magnitudes for stars on CCD frames for six metal-rich, low-latitude, previously unstudied globular clusters and one well-studied, metal-rich cluster (47 Tuc) have been derived and color-magnitude diagrams have been constructed. The photometry for stars in 47 Tuc are in good agreement with previous studies, while the V magnitudes of the horizontal-branch stars in the six program clusters do not agree with estimates based on secondary methods. The distances to these clusters are different from prior estimates. Redding values are derived for each program cluster. The horizontal branches of the program clusters all appear to lie entirely redwards of the red edge of the instability strip, as is normal for their metallicities.

Carbon dioxide selective adsorption within a highly stable mixed-ligand Zeolitic Imidazolate Framework

KAUST Repository

Huang, Lin; Xue, Ming; Song, Qingshan; Chen, Siru; Pan, Ying; Qiu, Shilun

2014-01-01

A new mixed-ligand Zeolitic Imidazolate Framework Zn4(2-mbIm) 3(bIm)5·4H2O (named JUC-160, 2-mbIm = 2-methylbenzimidazole, bIm = benzimidazole and JUC = Jilin University China) was synthesized with a solvothermal reaction of Zn(NO3) 2·6H2O, b

Earthquake magnitudes based on Coda-Derived Moment-Rate Spectra in Taiwan

Science.gov (United States)

Tu, F.; Gung, Y.; Yoo, S.; Rhie, J.

2010-12-01

We use the coda-derived moment-rate spectra method to estimate earthquake magnitudes in Taiwan. We extract coda-envelope at several frequency bands ranging from 0.03 to 8.0 hz using the horizontal component of broad-band waveform data recorded by BATS (Broadband Array in Taiwan for Siemology). We derived synthetic coda-envelope using various empirical frequency-dependent corrections mainly based upon Mayeda et al. (2003), which may account for all propagation, site and S-to-coda transfer function effects. After proper calibration and distance-corrections, the dimensionless coda amplitudes are used to determine the earthquake magnitude and source spectra. Selected events with magnitudes between 4 and 6 that occurred in 2009 are used to derive the empirical corrections and calibrations. We present detailed results of each procedure. Moreover, with the empirical corrections, we apply this measurement to an expanded data set and compare the derived coda-magnitude with other magnitude scales derived from conventional methods.

Non-specific vaginitis: diagnostic features and response to imidazole therapy (metronidazole, ornidazole).

Science.gov (United States)

Meech, R J; Loutit, J

1985-05-22

Detailed quantitative aerobic, anaerobic, fungal and mycoplasma flora was obtained for 43 women presenting with complaints of vaginal discharge and malodour. Clinical response was associated with eradication of the abnormal anaerobic flora, despite persistence of G vaginalis in nine (26%). Topical imidazole therapy appeared to have some advantage over oral therapy. Gram stains of vaginal swabs were found to be the most useful laboratory investigation.

Solidification of liquid electrolyte with imidazole polymers for quasi-solid-state dye-sensitized solar cells

International Nuclear Information System (INIS)

Wang Miao; Lin Yuan; Zhou Xiaowen; Xiao Xurui; Yang Lei; Feng Shujing; Li Xueping

2008-01-01

Quasi-solid-state electrolytes were prepared by employing the imidazole polymers to solidify the liquid electrolyte containing lithium iodide, iodine and ethylene carbonate (EC)/propylene carbonate (PC) mixed solvent. The ionic conductivity and diffusion behavior of triiodide in the quasi-solid-state electrolytes were examined in terms of the polymer content. Application of the quasi-solid-state electrolytes to the dye-sensitized solar cells, the maximum energy conversion efficiency of 7.6% (AM 1.5, 100 mW cm -2 ) was achieved. The dependence of the photovoltaic performance on the polymer content and on the different anions of the imidazole polymers was studied by electrochemical impedance spectroscopy and cyclic voltammetry. The results indicate the charge transfer behaviors occurred at nanocrystalline TiO 2 /electrolyte and Pt/electrolyte interface play an important role in influencing the photovoltaic performance of quasi-solid-state dye-sensitized solar cells

(Non-)symbolic magnitude processing in children with mathematical difficulties: A meta-analysis.

Science.gov (United States)

Schwenk, Christin; Sasanguie, Delphine; Kuhn, Jörg-Tobias; Kempe, Sophia; Doebler, Philipp; Holling, Heinz

2017-05-01

Symbolic and non-symbolic magnitude representations, measured by digit or dot comparison tasks, are assumed to underlie the development of arithmetic skills. The comparison distance effect (CDE) has been suggested as a hallmark of the preciseness of mental magnitude representations. It implies that two magnitudes are harder to discriminate when the numerical distance between them is small, and may therefore differ in children with mathematical difficulties (MD), i.e. low mathematical achievement or dyscalculia. However, empirical findings on the CDE in children with MD are heterogeneous, and only few studies assess both symbolic and non-symbolic skills. This meta-analysis therefore integrates 44 symbolic and 48 non-symbolic response time (RT) outcomes reported in nineteen studies (N=1630 subjects, aged 6-14 years). Independent of age, children with MD show significantly longer mean RTs than typically achieving controls, particularly on symbolic (Hedges' g=0.75; 95% CI [0.51; 0.99]), but to a significantly lower extent also on non-symbolic (g=0.24; 95% CI [0.13; 0.36]) tasks. However, no group differences were found for the CDE. Extending recent work, these meta-analytical findings on children with MD corroborate the diagnostic importance of magnitude comparison speed in symbolic tasks. By contrast, the validity of CDE measures in assessing MD is questioned. Copyright © 2017 Elsevier Ltd. All rights reserved.

Tumor Repression of VCaP Xenografts by a Pyrrole-Imidazole Polyamide

OpenAIRE

Hargrove, Amanda E.; Martinez, Thomas F.; Hare, Alissa A.; Kurmis, Alexis A.; Phillips, John W.; Sud, Sudha; Pienta, Kenneth J; Dervan, Peter B.

2015-01-01

Pyrrole-imidazole (Py-Im) polyamides are high affinity DNA-binding small molecules that can inhibit protein-DNA interactions. In VCaP cells, a human prostate cancer cell line overexpressing both AR and the TMPRSS2-ERG gene fusion, an androgen response element (ARE)-targeted Py-Im polyamide significantly downregulates AR driven gene expression. Polyamide exposure to VCaP cells reduced proliferation without causing DNA damage. Py-Im polyamide treatment also reduced tumor growth in a VCaP mouse ...

Slow-spreading submarine ridges in the South Atlantic as a significant oceanic iron source

CSIR Research Space (South Africa)

Saito, MA

2013-09-01

Full Text Available Low levels of the micronutrient iron limit primary production and nitrogen fixation in large areas of the global ocean. The location and magnitude of oceanic iron sources remain uncertain, however, owing to a scarcity of data, particularly...

Radio-prophylactic treatment with imidazole and/or Serotonin for Modulation of Tissue Catecholamines in whole body gamma irradiated Rats

International Nuclear Information System (INIS)

Hassan, S.H.M.; Roushdy, H.M.; Maklaad, Y.A.; El-Sayed, M.E.

1995-01-01

The present study has been conducted to evaluate the radioprotective effects of imidazole, serotonin and their combination on radiation induced reduction in catecholamine contents of the heart and adrenal glands in albino rat. The contribution of catecholamines in the radioprotective role of these agents has been evaluated. Whole-body gamma-irradiation (6 Gy) induced a significant reduction in heart and adrenal glands contents of catecholamine (epinephrine, norepinephrine and dopamine) one day post irradiation. Such reduction in catecholamine contents was more pronounced on the seventh day post exposure. Administration of imidazole (350 mg kg-1) or serotonin. (15 mg. kg-1) controlled the radiation induced reduction in catecholamine contents of heart as well as adrenal glands. Whereas, combination of imidazole (17 mg kg-1) serotonin (15 mg. kg-1) afforded a better protection than either agent given alone, in view that all the measured parameters could be fully restored to the values pre-irradiation. This study appreciate the usage of such combination as a prophylactic treatment for controlling the stress-state induced by irradiation which is associated with disturbed level of endogenous catecholamine contents in those sensitive patients undergoing radiotherapy. 2 tabs

Zinc (II) [tetra(4-methylphenyl)] Porphyrin: a Novel and Reusable Catalyst for Efficient Synthesis of 2,4,5-trisubstituted Imidazoles Under Ultrasound Irradiation

Energy Technology Data Exchange (ETDEWEB)

Safari, Javad; Khalili, Shiva Dehghan; Banitaba, Sayed Hossein; Dehghani, Hossein [Univ. of Kashan, Kashan (Iran, Islamic Republic of)

2011-10-15

An efficient three-component one-step synthesis of 2,4,5-trisubstituted imidazoles by condensation reaction of 1,2-diketones or α-hydroxyketones with aromatic aldehydes and ammonium acetate using Zinc (II) [tetra (4-methylphenyl)] porphyrin as a novel and reusable catalyst under ultrasound irradiation at ambient temperature is described. In this method, α-hydroxyketones as well as 1,2-diketones were converted to their corresponding 2,4,5-trisubstituted imidazoles in excellent yields.

Distance Measures for Information System Reengineering

NARCIS (Netherlands)

Poels, G.; Viaene, S.; Dedene, G.; Wangler, B.; Bergman, L.

2000-01-01

We present an approach to assess the magnitude and impact of information system reengineering caused by business process change. This approach is based on two concepts: object-oriented business modeling and distance measurement. The former concept is used to visualize changes in the business layer

Microwave-Assisted Solvent-Free Synthesis of Zeolitic Imidazolate Framework-67

Directory of Open Access Journals (Sweden)

Heng Zhang

2016-01-01

Full Text Available A microporous metal-organic framework (MOF, cobalt-based zeolitic imidazolate framework-67 (ZIF-67, was synthesized by the combination of solvent-free hand-mill and microwave irradiation, without any organic solvent and within 30 minutes. The hand-milling process can mix the reactants well by the virtue of high moisture/water absorption capacity of reactants. In addition, the outstanding electromagnetic wave absorption capability of cobalt leads to efficient conversion to MOF structures before carbonization. The obtained ZIF-67 possesses high surface area and micropore volume.

cis-Tetra­chloridobis(1H-imidazole-κN 3)platinum(IV)

Science.gov (United States)

Bokach, Nadezhda A.; Kukushkin, Vadim Yu.; Izotova, Yulia A.; Usenko, Natalia I.; Haukka, Matti

2012-01-01

In the title complex, cis-[PtCl4(C3H4N2)2], the PtIV ion lies on a twofold rotation axis and is coordinated in a slightly distorted octa­hedral geometry. The dihedral angle between the imidazole rings is 69.9 (2)°. In the crystal, mol­ecules are linked by N—H⋯Cl hydrogen bonds, forming a three-dimensional network. PMID:22590070

Model Studies of the Histidine-Tyrosine Cross-Link in Cytochrome c Oxidase Reveal the Flexible Substituent Effect of the Imidazole Moiety

Science.gov (United States)

Pratt, Derek A.; Pesavento, Russell P.; van der Donk, Wilfred A.

2010-01-01

Experimental and theoretical studies were carried out to interrogate the effect of an imidazole substituent in each of the ortho, meta, and para positions on the pKa, E°, and O–H BDE of phenol. The results reveal that imidazole substitution lowers the pKa of phenol and increases the E° of phenoxide due to its σ-electron withdrawing ability (σp− = +0.21, σm− = +0.45) but decreases the O–H BDE and E° of phenol due to its σ-electron-donating ability (σp+ = −0.45). PMID:15957934

Pore closure in zeolitic imidazolate frameworks under mechanical pressure.

Science.gov (United States)

Henke, Sebastian; Wharmby, Michael T; Kieslich, Gregor; Hante, Inke; Schneemann, Andreas; Wu, Yue; Daisenberger, Dominik; Cheetham, Anthony K

2018-02-14

We investigate the pressure-dependent mechanical behaviour of the zeolitic imidazolate framework ZIF-4 (M(im) 2 ; M 2+ = Co 2+ or Zn 2+ , im - = imidazolate) with high pressure, synchrotron powder X-ray diffraction and mercury intrusion measurements. A displacive phase transition from a highly compressible open pore ( op ) phase with continuous porosity (space group Pbca , bulk modulus ∼1.4 GPa) to a closed pore ( cp ) phase with inaccessible porosity (space group P 2 1 / c , bulk modulus ∼3.3-4.9 GPa) is triggered by the application of mechanical pressure. Over the course of the transitions, both ZIF-4 materials contract by about 20% in volume. However, the threshold pressure, the reversibility and the immediate repeatability of the phase transition depend on the metal cation. ZIF-4(Zn) undergoes the op-cp phase transition at a hydrostatic mechanical pressure of only 28 MPa, while ZIF-4(Co) requires about 50 MPa to initiate the transition. Interestingly, ZIF-4(Co) fully returns to the op phase after decompression, whereas ZIF-4(Zn) remains in the cp phase after pressure release and requires subsequent heating to switch back to the op phase. These variations in high pressure behaviour can be rationalised on the basis of the different electron configurations of the respective M 2+ ions (3d 10 for Zn 2+ and 3d 7 for Co 2+ ). Our results present the first examples of op-cp phase transitions ( i.e. breathing transitions) of ZIFs driven by mechanical pressure and suggest potential applications of these functional materials as shock absorbers, nanodampers, or in mechanocalorics.

DNA-Directed alkylating agents. 7. Synthesis, DNA interaction, and antitumor activity of bis(hydroxymethyl)- and bis(carbamate)-substituted pyrrolizines and imidazoles.

Science.gov (United States)

Atwell, G J; Fan, J Y; Tan, K; Denny, W A

1998-11-19

A series of bis(hydroxymethyl)-substituted imidazoles, thioimidazoles, and pyrrolizines and related bis(carbamates), linked to either 9-anilinoacridine (intercalating) or 4-(4-quinolinylamino)benzamide (minor groove binding) carriers, were synthesized and evaluated for sequence-specific DNA alkylation and cytotoxicity. The imidazole and thioimidazole analogues were prepared by initial synthesis of [(4-aminophenyl)alkyl]imidazole-, thioimidazole-, or pyrrolizine dicarboxylates, coupling of these with the desired carrier, and reduction to give the required bis(hydroxymethyl) alkylating moiety. The pyrrolizines were the most reactive alkylators, followed by the thioimidazoles, while the imidazoles were unreactive. The pyrrolizines and some of the thioimidazoles cross-linked DNA, as measured by agarose gel electrophoresis. Strand cleavage assays showed that none of the compounds reacted at purine N7 or N3 sites in the gpt region of the plasmid gpt2Eco, but the polymerase stop assay showed patterns of G-alkylation in C-rich regions. The corresponding thioimidazole bis(carbamates) were more selective than the bis(hydroxymethyl) pyrrolizines, with high-intensity bands at 5'-NCCN, 5'-NGCN and 5'-NCGN sequences in the PCR stopping assay ( indicates block sites). The data suggest that these targeted compounds, like the known thioimidazole bis(carbamate) carmethizole, alkylate exclusively at guanine residues via the 2-amino group, with little or no alkylation at N3 and N7 guanine or adenine sites. The cytotoxicities of the compounds correlated broadly with their reactivities, with the bis(hydroxymethyl)imidazoles being the least cytotoxic (IC50s >1 microM; P388 leukemia) and with the intercalator-linked analogues being more cytotoxic than the corresponding minor-groove-targeted ones. This was true also for the more reactive thioimidazole bis(carbamates) (IC50s 0.8 and 11 microM, respectively), but both were more active than the analogous "untargeted" carmethizole (IC50 20

Electron spin resonance and E.N.D.O.R. double resonance study of free radicals produced by gamma irradiation of imidazole single crystals; Etude par resonance paramagnetique electronique et double resonance E.N.D.O.R. des radicaux libres crees par irradiation gamma de monocristaux d'imidazole

Energy Technology Data Exchange (ETDEWEB)

Lamotte, B [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1970-07-01

Gamma irradiation of imidazole single crystals at 300 deg. K gives two radicals. Identification and detailed studies of their electronic and geometric structure have been made by ESR and ENDOR techniques. A study of the hydrogen bonded protons hyperfine tensor is made and let us conclude to the inexistence of movement and tunneling of these protons. The principal low temperature radical, produced by gamma irradiation at 77 deg. K has been also studied by ESR and a model has been proposed. (author) [French] L'irradiation gamma de monocristaux d'imidazole a 300 deg. K conduit a deux radicaux dont l'identification et l'etude detaillee des structures electroniques et geometriques ont ete obtenues par la resonance paramagnetique electronique (RPE) et la double resonance ENDOR. En particulier l'examen des protons de la liaison hydrogene permet de conclure, pour ceux-ci, a l'inexistence de tout mouvement par effet tunnel. De plus, l'analyse des spectres de RPE du radical principal cree par irradiation gamma de l'imidazole a 77 deg. K nous a permis de proposer un modele pour ce radical. (auteur)

Increased urinary imidazolepropionic acid, n-acetylhistamine and other imidazole compounds in patients with intestinal disorders

NARCIS (Netherlands)

Heiden, C. van der; Wadman, S.K.; Bree, P.K. de; Wauters, E.A.K.

In 26 out of a large group of patients with gastrointestinal disorders abnormal urinary imidazole excretion patterns were found. Most frequently excessive or increased amounts of imidazolepropionic acid (ImPA) occurred, and as next N-acetylhistamine was excreted in excess. In a number of cases the

Synthesis and evaluation of alpha-[[(2-haloethyl)amino]methyl]-2- nitro-1H-imidazole-1-ethanols as prodrugs of alpha-[(1-aziridinyl)methyl]-2- nitro-1H-imidazole-1-ethanol (RSU-1069) and its analogues which are radiosensitizers and bioreductively activated cytotoxins

International Nuclear Information System (INIS)

Jenkins, T.C.; Naylor, M.A.; O'Neill, P.; Threadgill, M.D.; Cole, S.; Stratford, I.J.; Adams, G.E.; Fielden, E.M.; Suto, M.J.; Stier, M.A.

1990-01-01

alpha-[(1-Aziridinyl)methyl]-2-nitro-1H-imidazole-1-ethanols, of general formula ImCH2CH(OH)CH2NCR1R2CR3R4, where Im = 2-nitroimidazole and R1, R2, R3, R4 = H, Me, are radiosensitizers and selective bioreductively activated cytotoxins toward hypoxic tumor cells in vitro and in vivo. Treatment of the aziridines with hydrogen halide in acetone or aqueous acetone gave the corresponding 2-haloethylamines of general formula ImCH2CH(OH)CH2(+)-NH2CR1R2CR3R4X X-, where R1, R2, R3, R4 = H, Me, and X = F, Cl, Br, I. These 2-haloethylamines were evaluated as prodrugs of the parent aziridines. The rates of ring closure in aqueous solution at pH approximately 6 were found to increase with increasing methyl substitution and to depend on the nature of the leaving group (I approximately Br greater than Cl much greater than F). A competing reaction of ImCH2CH(OH)CH2+NH2CH2CH2X X- (X = Cl, Br) with aqueous HCO3- ions gives 3-[2-hyroxy-3-(2-nitro-1H-imidazol-1-yl)propyl]-2-oxazolidinone. The activities of these prodrugs as radiosensitizers or as bioreductively activated cytotoxins were consistent with the proportion converted to the parent aziridine during the course of the experiment. alpha-[[(2-Bromoethyl)amino]methyl]-2-nitro-1H-imidazole-1- ethanol (RB 6145, 10), the prodrug of alpha-[(1-aziridinyl)methyl]-2-nitro-1H-imidazole-1-ethanol (RSU-1069, 3), is identified as the most useful compound in terms of biological activity and rate of ring closure under physiological conditions

CNTs grown on nanoporous carbon from zeolitic imidazolate frameworks for supercapacitors.

Science.gov (United States)

Kim, Jeonghun; Young, Christine; Lee, Jaewoo; Park, Min-Sik; Shahabuddin, Mohammed; Yamauchi, Yusuke; Kim, Jung Ho

2016-10-27

Carbon nanotubes (CNT) grown on nanoporous carbon (NPC), which yields coexisting amorphous and graphitic nanoarchitectures, have been prepared on a large scale from zeolitic imidazolate framework (ZIF) by introducing bimetallic ions (Co 2+ and Zn 2+ ). Interestingly, the hybrid Co/Zn-ZIF-derived NPC showed rich graphitic CNTs on the surface. This NPC was utilized for a coin-type supercapacitor cell with an aqueous electrolyte, which showed enhanced retention at high current density and good stability over 10 000 cycles.

Nonenzymatic electrochemical sensor based on imidazole-functionalized graphene oxide for progesterone detection.

Science.gov (United States)

Gevaerd, Ava; Blaskievicz, Sirlon F; Zarbin, Aldo J G; Orth, Elisa S; Bergamini, Márcio F; Marcolino-Junior, Luiz H

2018-07-30

The modification of electrode surfaces has been the target of study for many researchers in order to improve the analytical performance of electrochemical sensors. Herein, the use of an imidazole-functionalized graphene oxide (GO-IMZ) as an artificial enzymatic active site for voltammetric determination of progesterone (P4) is described for the first time. The morphology and electrochemical performance of electrode modified with GO-IMZ were characterized by scanning electron microscopy and cyclic voltammetry, respectively. Under optimized conditions, the proposed sensor showed a synergistic effect of the GO sheets and the imidazole groups anchored on its backbone, which promoted a significant enhancement on electrochemical reduction of P4. Figures of merits such as linear dynamic response for P4 concentration ranging from 0.22 to 14.0 μmol L -1 , limit of detection of 68 nmol L -1 and limit of quantification and 210 nmol L -1 were found. In addition, presented a higher sensitivity, 426 nA L µmol -1 , when compared to the unmodified electrode. Overall, the proposed device showed to be a promising platform for a simple, rapid, and direct analysis of progesterone. Copyright © 2018 Elsevier B.V. All rights reserved.

Model studies of the Cu(B) site of cytochrome c oxidase utilizing a Zn(II) complex containing an imidazole-phenol cross-linked ligand.

Science.gov (United States)

Pesavento, Russell P; Pratt, Derek A; Jeffers, Jerry; van der Donk, Wilfred A

2006-07-21

Cytochrome c oxidase, the enzyme complex responsible for the four-electron reduction of O2 to H2O, contains an unusual histidine-tyrosine cross-link in its bimetallic heme a3-CuB active site. We have synthesised an unhindered, tripodal chelating ligand, BPAIP, containing the unusual ortho-imidazole-phenol linkage, which mimics the coordination environment of the CuB center. The ligand was used to investigate the physicochemical (pKa, oxidation potential) and coordination properties of the imidazole-phenol linkage when bound to a dication. Zn(II) coordination lowers the pKa of the phenol by 0.6 log units, and increases the potential of the phenolate/phenoxyl radical couple by approximately 50 mV. These results are consistent with inductive withdrawal of electron density from the phenolic ring. Spectroscopic data and theoretical calculations (DFT) were used to establish that the cationic complex [Zn(BPAIP)Br]+ has an axially distorted trigonal bipyramidal structure, with three coordinating nitrogen ligands (two pyridine and one imidazole) occupying the equatorial plane and the bromide and the tertiary amine nitrogen of the tripod in the axial positions. Interestingly, the Zn-Namine bonding interaction is weak or absent in [Zn(BPAIP)Br]+ and the complex gains stability in basic solutions, as indicated by 1H NMR spectroscopy. These observations are supported by theoretical calculations (DFT), which suggest that the electron-donating capacity of the equatorial imidazole ligand can be varied by modulation of the protonation and/or redox state of the cross-linked phenol. Deprotonation of the phenol makes the equatorial imidazole a stronger sigma-donor, resulting in an increased Zn-Nimd interaction and thereby leading to distortion of the axial ligand axis toward a more tetrahedral geometry.

Crystal structures of eight 3D molecular adducts derived from bis-imidazole, bis(benzimidazole), and organic acids

Science.gov (United States)

Ding, Aihua; Jin, Shouwen; Jin, Shide; Hu, KaiKai; Lin, Zhihao; Liu, Hui; Wang, Daqi

2018-01-01

Cocrystallization of the bis(imidazole)/bis(benzimidazole) with a series of organic acids gave a total of eight molecular adducts with the compositions: (3,6-bis(imidazole-1-yl)pyridazine): (trichloroacetic acid)2(1) [(H2L1)2+ · (tca-)2, L1 = 3,6-bis(imidazole-1-yl)pyridazine, tca- = trichloroacetate], (bis(N-imidazolyl)methane): (suberic acid) (2) [(L2) · (H2suba), L2 = bis(N-imidazolyl)methane, H2suba = suberic acid], bis(N-imidazolyl)methane: (3-nitrophthalic acid): 3H2O (3) [(H2L2)2+ · (3-Hnpa-)2 · 3H2O, 3-Hnpa- = 3-nitro hydrogenphthalate], (bis(N-imidazolyl)butane)0.5: (4-nitrophthalic acid): H2O (4) [(H2L3)0.5+ · (4-Hnpa-)- · H2O, L3 = bis(N-imidazolyl)butane, 4-Hnpa- = 4-nitro hydrogenphthalate], (1-(3-(1H-benzimidazol-1-yl)propyl)-1H-benzimidazole): (3,5-dinitrosalicylic acid) (5) [(HL4) · (3,5-dns-), L4 = 1-(3-(1H-benzimidazol-1-yl)propyl)-1H-benzimidazole, 3,5-dns- = 3,5-dinitrosalicylate], (1-(3-(1H-benzimidazol-1-yl)propyl)-1H-benzimidazole): (3-nitrophthalic acid) (6) [(H2L4) · (3-npa2-), L4 = 1-(3-(1H-benzimidazol-1-yl)propyl)-1H-benzimidazole, 3-npa2-=3-nitrogenphthalate], (bis(N-imidazolyl)butane): (pamoic acid) (7) [(H2L3) · (pam), pam = pamoate], and (3,6-bis(imidazole-1-yl)pyridazine): (1,5-naphthalenedisulfonic acid) [(H2L1)2+ · (npda)2- = 1,5-naphthalenedisulfonate] (8). The eight adducts have been characterized by X-ray diffraction technique, infrared spectrum, and elemental analysis, and the melting points of all adducts were also reported. And their structural and supramolecular aspects are fully analyzed. The result reveals that among the eight investigated crystals both the end ring N in the bis(imidazole) moieties are protonated when the organic acids are deprotonated except 2, and 5, and the crystal packing is interpreted in terms of the strong ionic Nsbnd H⋯O H-bond between the imidazolium and the deprotonated acidic groups. Except the Nsbnd H⋯O H-bond, the Osbnd H⋯O H-bonds were also found at the salts 3, 4

Analysis of color-magnitude diagrams from three large Magellanic Cloud clusters

International Nuclear Information System (INIS)

Jones, J.H.

1985-01-01

The color-magnitude diagrams of three LMC clusters and a field were derived from photographic and CCD data provided by Dr. P.J. Flower of Clemson University and Dr. R. Schommer of Rutgers University. The photographic data were scanned and converted to intensity images at KPNO. The stellar photometry program RICHFLD was used to measure the raw magnitudes from these images. Problems with the standard sequence on the plate kept the color terms for the photographic data from being well determined. A version of DAOPHOT was installed on the VAX 11/280s at Clemson and was used to measure the magnitudes from the CCD images of NGC 2249. These magnitudes were used to define another photoelectric sequence for the photographic data which were used to determine a well defined transformation into the standard BV system. The CMDs derived from both the photographic and CCD images of NGC 2249 showed a gap near the tip of the MS. This gap was taken to be the period of rapid evolution just after core hydrogen exhaustion. Using a true distance modulus of 18.3 for the LMC and a reddening taken from the literature, an age of 600 +/- 75 million years was found for NGC 2249. Comparing the CMD of SL 889 to that of NGC 2249 gives a similar age for this small LMC cluster. A subgiant branch was identified in the CMD of NGC 2241. Comparison to old metal poor galactic clusters gave an age near 4 billion years, favoring the short distance scale to the LMC

Changes in the hydration structure of imidazole upon protonation: Neutron scattering and molecular simulations

Czech Academy of Sciences Publication Activity Database

Duboué-Dijon, Elise; Mason, Philip E.; Fischer, H. E.; Jungwirth, Pavel

2017-01-01

Roč. 146, č. 18 (2017), č. článku 185102. ISSN 0021-9606 R&D Projects: GA ČR(CZ) GBP208/12/G016 Institutional support: RVO:61388963 Keywords : imidazole protonation * molecular dynamics * neutron scattering Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 2.965, year: 2016

The orbit of Phi Cygni measured with long-baseline optical interferometry - Component masses and absolute magnitudes

Science.gov (United States)

Armstrong, J. T.; Hummel, C. A.; Quirrenbach, A.; Buscher, D. F.; Mozurkewich, D.; Vivekanand, M.; Simon, R. S.; Denison, C. S.; Johnston, K. J.; Pan, X.-P.

1992-01-01

The orbit of the double-lined spectroscopic binary Phi Cygni, the distance to the system, and the masses and absolute magnitudes of its components are presented via measurements with the Mar III Optical Interferometer. On the basis of a reexamination of the spectroscopic data of Rach & Herbig (1961), the values and uncertainties are adopted for the period and the projected semimajor axes from the present fit to the spectroscopic data and the values of the remaining elements from the present fit to the Mark III data. The elements of the true orbit are derived, and the masses and absolute magnitudes of the components, and the distance to the system are calculated.

Computational Developments for Distance Determination of Stellar ...

Indian Academy of Sciences (India)

that the members of the group scatter around a mean absolute magnitude in. Gaussian ..... Due to its important role in distance determination (e.g., equation 9) this tempted us to establish analytical ..... Communications, 40, 39–61. Sharaf, M. A. ...

Tannic acid Catalyzed an Efficient Synthesis of 2,4,5-Triaryl-1H-Imidazole

Directory of Open Access Journals (Sweden)

Shitole Nana Vikram

2013-05-01

Full Text Available Tannic acid (C76H52O46 has been found to be an efficient catalyst for one-pot synthesis of 2,4,5-triaryl substituted imidazoles by the reaction of an arylaldehyde, benzyl/benzoin and an ammonium acetate. The short reaction time and excellent yields making this protocol practical and economically attractive.

Spectroscopic analysis and molecular docking of imidazole derivatives and investigation of its reactive properties by DFT and molecular dynamics simulations

Science.gov (United States)

Thomas, Renjith; Hossain, Mossaraf; Mary, Y. Sheena; Resmi, K. S.; Armaković, Stevan; Armaković, Sanja J.; Nanda, Ashis Kumar; Ranjan, Vivek Kumar; Vijayakumar, G.; Van Alsenoy, C.

2018-04-01

Solvent-free synthesis pathway for obtaining two imidazole derivatives (2-chloro-1-(4-methoxyphenyl)-4,5-dimethyl-1H-imidazole (CLMPDI) and 1-(4-bromophenyl)-2-chloro-4,5-dimethyl-1H-imidazole (BPCLDI) has been reported in this work, followed by detailed experimental and computational spectroscopic characterization and reactivity study. Spectroscopic methods encompassed IR, FT-Raman and NMR techniques, with the mutual comparison of experimentally and computationally obtained results at DFT/B3LYP level of theory. Reactivity study based on DFT calculations encompassed molecular orbitals analysis, followed by calculations of molecular electrostatic potential (MEP) and average local ionization energy (ALIE) values, Fukui functions and bond dissociation energies (BDE). Additionally, the stability of title molecules in water has been investigated via molecular dynamics (MD) simulations, while interactivity with aspulvinonedimethylallyl transferase protein has been evaluated by molecular docking procedure. CLMPDI compound showed antimicrobial activity against all four bacterial strain in both gram positive and gram negative bacteria while, BPCLDI showed only in gram positive bacteria, Staphylococcus Aureus (MTCC1144). The first order hyperpolarizability of CLMPDI and BPCLDI are 20.15 and 6.10 times that of the standard NLO material urea.

Near-IR TRGB Distance to Nearby Dwarf Irregular Galaxy NGC 6822

Directory of Open Access Journals (Sweden)

Y.-J. Sohn

2008-09-01

Full Text Available We report the distance modulus of nearby dwarf irregular galaxy NGC 6822 estimated from the so-called Tip of Red-giant Branch (TRGB method. To detect the apparent magnitudes of the TRGB we use the color-magnitude diagrams (CMDs and luminosity functions (LFs in the near-infrared JHK bands. Foreground stars, main-sequence stars, and supergiant stars have been classified on the (g - K, g plane and removed on the near-infrared CMDs, from which only RGB and AGB stars are remained on the CMDs and LFs. By applying the Savitzky-Golay filter to the obtained LFs and detecting the peak in the second derivative of the observed LFs, we determined the apparent magnitudes of the TRGB. Theoretical absolute magnitudes of the TRGB are estimated from Yonsei-Yale isochrones with the age of 12Gyr and the metallicity range of -2.0 <[Fe/H]< -0.5. The derived values of distance modulus to NGC 6822 are (m - M

DFT/TDDFT investigation on the electronic structures and photophysical properties of phosphorescent iridium(III) complexes with 2-(pyridin-2-yl)-benzo[d]imidazole ligand

Energy Technology Data Exchange (ETDEWEB)

Shang, Xiaohong, E-mail: shangxiaohong58@aliyun.com [College of Chemistry and Life Science, Changchun University of Technology, Changchun 130012 (China); Han, Deming [School of Life Science and Technology, Changchun University of Science and Technology, Changchun 130022 (China); Li, Dongfeng [College of Chemistry and Life Science, Changchun University of Technology, Changchun 130012 (China); Zhang, Gang [State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023 (China)

2014-03-15

We have reported a theoretical analysis of a series of heteroleptic iridium(III) complexes (mpmi){sub 2}Ir(pybi) [mpmi=1-(4-tolyl)-3-methyl-imidazole, pybi=2-(pyridin-2-yl)-benzo[d]imidazole] (1a), (fpmi){sub 2}Ir(pybi) [fpmi=1-(4-fluoro-phenyl)-3-methyl-imidazole] (1b), (tfpmi){sub 2}Ir(pybi) [tfpmi=1-methyl-3-(4-trifluoromethyl-phenyl)-imidazole] (1c), (pypmi){sub 2}Ir(pybi) [pypmi=3-(3-methyl-imidazol)-pyrazole] (2a), (phpymi){sub 2}Ir(pybi) [phpymi=3-(3-methyl-imidazol)-5-phenyl-pyrazole] (2b), and (inpymi){sub 2}Ir(pybi) [inpymi=3-(3-methyl-imidazol)-indeno[1,2-c]pyrazole] (2c) by using the density functional theory (DFT) method to investigate their electronic structures and photophysical properties and obtain further insights into the phosphorescent efficiency mechanism. By changing cyclometalated ligands, the conjugation length, and substituents of the cyclometalated ligands, one can tune the emission color from green (λ{sub em}=520 nm) to orange (λ{sub em}=592 nm). Complexes 1a, 1b, 2a, and 2b have the almost identical emission wavelength about 550 nm, while 592 nm for 1c and 520 nm for 2c are red shifted and blue shifted, respectively, relative to 1a. The calculated results indicate that, for 1b and 1c, the substituents of −F and −CF{sub 3} at the phenyl moiety cause a poor hole-injection ability compared with that of 1a. For all these complexes studied, the hole-transporting performances are better than the electron-transporting ones. The difference between reorganization energies for hole transport (λ{sub ih}) and reorganization energies for electron transport (λ{sub ie}) for complex 1c are relatively smaller, indicating that the hole and electron transfer balance could be achieved more easily in the emitting layer. The alteration of cyclometalated ligands with different conjugation lengths and substituents has an impact on the optoelectronic properties of these complexes. It is believed that the larger metal to ligand charge transfer (MLCT

Inoculation Effects of Cast Iron

Directory of Open Access Journals (Sweden)

E. Fraś

2012-12-01

Full Text Available The paper presents a solidification sequence of graphite eutectic cells of A and D types, as well as globular and cementite eutectics. The morphology of eutectic cells in cast iron, the equations for their growth and the distances between the graphite precipitations in A and D eutectic types were analyzed. It is observed a critical eutectic growth rate at which one type of eutectic transformed into another. A mathematical formula was derived that combined the maximum degree of undercooling, the cooling rate of cast iron, eutectic cell count and the eutectic growth rate. One type of eutectic structure turned smoothly into the other at a particular transition rate, transformation temperature and transformational eutectic cell count. Inoculation of cast iron increased the number of eutectic cells with flake graphite and the graphite nodule count in ductile iron, while reducing the undercooling. An increase in intensity of inoculation caused a smooth transition from a cementite eutectic structure to a mixture of cementite and D type eutectic structure, then to a mixture of D and A types of eutectics up to the presence of only the A type of eutectic structure. Moreover, the mechanism of inoculation of cast iron was studied.

Weighted Distances in Scale-Free Configuration Models

Science.gov (United States)

Adriaans, Erwin; Komjáthy, Júlia

2018-01-01

In this paper we study first-passage percolation in the configuration model with empirical degree distribution that follows a power-law with exponent τ \\in (2,3) . We assign independent and identically distributed (i.i.d.) weights to the edges of the graph. We investigate the weighted distance (the length of the shortest weighted path) between two uniformly chosen vertices, called typical distances. When the underlying age-dependent branching process approximating the local neighborhoods of vertices is found to produce infinitely many individuals in finite time—called explosive branching process—Baroni, Hofstad and the second author showed in Baroni et al. (J Appl Probab 54(1):146-164, 2017) that typical distances converge in distribution to a bounded random variable. The order of magnitude of typical distances remained open for the τ \\in (2,3) case when the underlying branching process is not explosive. We close this gap by determining the first order of magnitude of typical distances in this regime for arbitrary, not necessary continuous edge-weight distributions that produce a non-explosive age-dependent branching process with infinite mean power-law offspring distributions. This sequence tends to infinity with the amount of vertices, and, by choosing an appropriate weight distribution, can be tuned to be any growing function that is O(log log n) , where n is the number of vertices in the graph. We show that the result remains valid for the the erased configuration model as well, where we delete loops and any second and further edges between two vertices.

Extrap with iron-cored coils

International Nuclear Information System (INIS)

Lehnert, B.

1985-05-01

In Extrap configurations there is a high average beta value with respect to the plasma confinement volume. The externally imposed magnetic field which is required for stabilization therefore comes out to have a rather moderate strength, even under expected reactor conditions. As a consequence, this field can be generated not only by conventional external conductor arrangements, but also by iron-cored coils being operated below the saturation limit. A proposal for such iron-cored coil systems is presented in this paper. As compared to conventional conductors, this has the advantage of localizing the magnetic energy of the externally imposed magnetic field mainly to the discharge vessel and the plasma volume, thereby increasing the engineering beta value substantially. Also the problems of the coil stresses and of irradiation of the coils appear to become simplified, as well as replacement of the coil system. A main limitation of this proposal is due to combination of iron core saturation with the required stabilization effect from an ion Larmor radius of sufficient relative magnitude. This limitaion requires further investigation, especially in the full-scale reactor case. Also the modifications of the field geometry by iron core shaping needs further analysis. (Author)

Imidazole-containing phthalazine derivatives inhibit Fe-SOD performance in Leishmania species and are active in vitro against visceral and mucosal leishmaniasis.

Science.gov (United States)

Sánchez-Moreno, M; Gómez-Contreras, F; Navarro, P; Marín, C; Ramírez-Macías, I; Rosales, M J; Campayo, L; Cano, C; Sanz, A M; Yunta, M J R

2015-07-01

The in vitro leishmanicidal activity of a series of imidazole-containing phthalazine derivatives 1-4 was tested on Leishmania infantum, Leishmania braziliensis and Leishmania donovani parasites, and their cytotoxicity on J774·2 macrophage cells was also measured. All compounds tested showed selectivity indexes higher than that of the reference drug glucantime for the three Leishmania species, and the less bulky monoalkylamino substituted derivatives 2 and 4 were clearly more effective than their bisalkylamino substituted counterparts 1 and 3. Both infection rate measures and ultrastructural alterations studies confirmed that 2 and 4 were highly leishmanicidal and induced extensive parasite cell damage. Modifications to the excretion products of parasites treated with 2 and 4 were also consistent with substantial cytoplasmic alterations. On the other hand, the most active compounds 2 and 4 were potent inhibitors of iron superoxide dismutase enzyme (Fe-SOD) in the three species considered, whereas their impact on human CuZn-SOD was low. Molecular modelling suggests that 2 and 4 could deactivate Fe-SOD due to a sterically favoured enhanced ability to interact with the H-bonding net that supports the antioxidant features of the enzyme.

Characteristics analysis on a superconductor resonance coil WPT system according to cooling vessel materials in different distances

International Nuclear Information System (INIS)

Jeong, In-Sung; Lee, Yu-Kyeong; Choi, Hyo-Sang

2016-01-01

Highlights: • WPT using the superconductor coil was needed research for cooling vessel. FRP, bakelite, polystyrene, aluminum, and iron were applied as the cooling vessel material to analyze the WPT distance efficiency. • When the distance between the transmitter and receiver coils was 2000 mm, FRP being used for the cooling vessel made the transmission efficiency higher than any other materials. The efficiency and distance of sending power can be improved in the superconductor coil if the cooling vessel is made with FRP. - Abstract: The interest in wireless power transfer (WPT) that can send power without using wires has been increasing recently. Especially, there is a great interest in the wireless power devices for portable IT devices. The WPT devices that have been developed so far use the magnetic induction method, and they are not active due to their distance problem. A magnetic resonance WPT method was developed and has been actively researched to resolve this problem. A superconductor coil was applied in this study to increase the efficiency of the magnetic resonance WPT. FRP, bakelite, polystyrene, aluminum, and iron were applied as the cooling vessel material to analyze the WPT distance. The distance between the transmitter and receiver coils started from 800 mm and was increased by 200 mm. The reflection coefficient was measured at each distance. As a result, FRP, bakelite, plastic PVC, polystyrene of the reflection coefficient was similar. From among these FRP being used for the cooling vessel made the transmission characteristics higher than any other materials when the distance between the transmitter and receiver coils was 2,000 mm. On the other hand, the reflection coefficient dropped when iron was used. It is estimated based on the experimental results that the wireless power transmission characteristics and distance of sending power can be improved in the superconductor coil if the cooling vessel is made with FRP.

Characteristics analysis on a superconductor resonance coil WPT system according to cooling vessel materials in different distances

Energy Technology Data Exchange (ETDEWEB)

Jeong, In-Sung, E-mail: no21park@hanmail.net; Lee, Yu-Kyeong; Choi, Hyo-Sang, E-mail: hyosang@chosun.ac.kr

2016-11-15

Highlights: • WPT using the superconductor coil was needed research for cooling vessel. FRP, bakelite, polystyrene, aluminum, and iron were applied as the cooling vessel material to analyze the WPT distance efficiency. • When the distance between the transmitter and receiver coils was 2000 mm, FRP being used for the cooling vessel made the transmission efficiency higher than any other materials. The efficiency and distance of sending power can be improved in the superconductor coil if the cooling vessel is made with FRP. - Abstract: The interest in wireless power transfer (WPT) that can send power without using wires has been increasing recently. Especially, there is a great interest in the wireless power devices for portable IT devices. The WPT devices that have been developed so far use the magnetic induction method, and they are not active due to their distance problem. A magnetic resonance WPT method was developed and has been actively researched to resolve this problem. A superconductor coil was applied in this study to increase the efficiency of the magnetic resonance WPT. FRP, bakelite, polystyrene, aluminum, and iron were applied as the cooling vessel material to analyze the WPT distance. The distance between the transmitter and receiver coils started from 800 mm and was increased by 200 mm. The reflection coefficient was measured at each distance. As a result, FRP, bakelite, plastic PVC, polystyrene of the reflection coefficient was similar. From among these FRP being used for the cooling vessel made the transmission characteristics higher than any other materials when the distance between the transmitter and receiver coils was 2,000 mm. On the other hand, the reflection coefficient dropped when iron was used. It is estimated based on the experimental results that the wireless power transmission characteristics and distance of sending power can be improved in the superconductor coil if the cooling vessel is made with FRP.

Molecular Computational Investigation of Electron Transfer Kinetics across Cytochrome-Iron Oxide Interfaces

International Nuclear Information System (INIS)

Kerisit, Sebastien N.; Rosso, Kevin M.; Dupuis, Michel; Valiev, Marat

2007-01-01

The interface between electron transfer proteins such as cytochromes and solid phase mineral oxides is central to the activity of dissimilatory-metal reducing bacteria. A combination of potential-based molecular dynamics simulations and ab initio electronic structure calculations are used in the framework of Marcus' electron transfer theory to compute elementary electron transfer rates from a well-defined cytochrome model, namely the small tetraheme cytochrome (STC) from Shewanella oneidensis, to surfaces of the iron oxide mineral hematite (a-Fe2O3). Room temperature molecular dynamics simulations show that an isolated STC molecule favors surface attachment via direct contact of hemes I and IV at the poles of the elongated axis, with electron transfer distances as small as 9 Angstroms. The cytochrome remains attached to the mineral surface in the presence of water and shows limited surface diffusion at the interface. Ab initio electronic coupling matrix element (VAB) calculations of configurations excised from the molecular dynamics simulations reveal VAB values ranging from 1 to 20 cm-1, consistent with nonadiabaticity. Using these results, together with experimental data on the redox potential of hematite and hemes in relevant cytochromes and calculations of the reorganization energy from cluster models, we estimate the rate of electron transfer across this model interface to range from 1 to 1000 s-1 for the most exothermic driving force considered in this work, and from 0.01 to 20 s-1 for the most endothermic. This fairly large range of electron transfer rates highlights the sensitivity of the rate upon the electronic coupling matrix element, which is in turn dependent on the fluctuations of the heme configuration at the interface. We characterize this dependence using an idealized bis-imidazole heme to compute from first principles the VAB variation due to porphyrin ring orientation, electron transfer distance, and mineral surface termination. The electronic

Synthesis, Crystal Structure and Luminescent Property of A Novel Cd(II) Coordination Polymer with Bis-imidazole Ligand

International Nuclear Information System (INIS)

Zhou, Yong Hong

2013-01-01

The key to the successful design of metal-organic coordination polymers is the judicious selection of organic ligand. Recently, polydentate aromatic nitrogen heterocyclic ligands with five-membered rings have been well-studied in the construction of supramolecular structure for their N-coordinated sites apt to coordinating to transition metals. Similar to six-membered N-heterocyclic ligands, the azole-based five-membered N-heterocyclic ligands, such as imidazoles, triazoles and tetrazoles have been extensively employed in the construction of various coordination polymers with diverse topologies and interesting properties. The bis(azole) ligands in which N-donor azole rings (imidazole, triazole, or tetrazole) are separated by alkyl, (CH 2 ) n , spacers are good choices for flexible bridging ligands. The conformational flexibility of the spacers makes the ligands adaptable to various coordination networks with one-, two-, and three dimensional structures

78 FR 34160 - Union Pacific Railroad Company-Abandonment Exemption-In Iron County, Utah

Science.gov (United States)

2013-06-06

... DEPARTMENT OF TRANSPORTATION Surface Transportation Board [Docket No. AB 33 (Sub-No. 283X)] Union Pacific Railroad Company--Abandonment Exemption--In Iron County, Utah Union Pacific Railroad Company (UP... Cedar City, a total distance of 1.03 miles in Iron County, Utah (the Line). The Line traverses United...

Influence of surface topography on the surface durability of steam oxidised sintered iron

Directory of Open Access Journals (Sweden)

José Daniel Biasoli de Mello

2005-06-01

Full Text Available Durability of surfaces has been reported as the main factor affecting tribological behavior of steam oxidised sintered iron. The presence of surface pores and their negative influence on load bearing capacity, suggest that surface topography might play an important role on the durability of the oxide layer. In this paper, the influence of compaction pressure and powder grade on surface topography, and as a consequence, its effect on the tribological behavior of steam oxidised sintered iron has been analysed. Specimens prepared from atomised iron powders with different sizes were compacted using 4 different pressures, sintered, and then subjected to steam treatment. Tribological characterisation was carried out in a reciprocating sliding wear test. Although the processing parameters affected the surface topography to a considerable extent, the main influence may be attributed to powder grade. A strong influence of surface topography on the durability distance, evaluated in terms of the evolution of contact resistance with total sliding distance, has been highlighted. Surfaces which were smoother and had high load-carrying capacity were always associated with a higher durability distance.

Theoretical Study of Spin Crossover in 30 Iron Complexes

DEFF Research Database (Denmark)

Kepp, Kasper Planeta

2016-01-01

Spin crossover was studied in 30 iron complexes using density functional theory to quantify the direction and magnitude of dispersion, relativistic effects, zero-point energies, and vibrational entropy. Remarkably consistent entropy−enthalpy compensation was identified. Zero-point energies favor...

Imidazole incorporated semicarbazone derivatives as a new class of anticonvulsants: design, synthesis and in-vivo screening.

Science.gov (United States)

Amir, Mohammad; Ali, Israr; Hassan, Mohd Zaheen

2013-06-01

A series of novel imidazole incorporated semicarbazones was synthesized using an appropriate synthetic route and characterized by spectral analysis (IR, 1H NMR, 13C NMR and Mass). The anticonvulsant activity of the synthesized compounds was determined using doses of 30, 100, and 300 mg kg-1 against maximal electroshock seizure (MES), subcutaneous pentylenetetrazole (scPTZ) induced seizure and minimal neurotoxicity test. Six compounds exhibited protection in both models and 2-(1-(4-chlorophenyl)-2-(1H-imidazol-1-yl)ethylidene)-N-p-tolylsemicarbazone emerged as the most active compound of the series without any neurotoxicity and significant CNS depressant effect. Liver enzyme estimations (SGOT, SGPT, Alkaline phosphatase) of the compound also showed no significant change in the enzymes levels. Moreover, it caused 80% elevation of γ-amino butyric acid (GABA) levels in the whole mice brain, thus indicating that it could be a promising candidate in designing of a potent anticonvulsant drug.

Preparation of an aminopropyl imidazole-modified silica gel as a sorbent for solid-phase extraction of carboxylic acid compounds and polycyclic aromatic hydrocarbons.

Science.gov (United States)

Wang, Na; Guo, Yong; Wang, Licheng; Liang, Xiaojing; Liu, Shujuan; Jiang, Shengxiang

2014-05-21

In this paper, a kind of aminopropyl imidazole-modified silica sorbent was synthesized and used as a solid-phase extraction (SPE) sorbent for the determination of carboxylic acid compounds and polycyclic aromatic hydrocarbons (PAHs). The resultant aminopropyl imidazole-modified silica sorbent was characterized by Fourier transform infrared spectroscopy (FT-IR) and elemental analysis (EA) to ensure the successful binding of aminopropyl imidazole on the surface of silica gel. Then the aminopropyl imidazole-modified silica sorbent served as a SPE sorbent for the enrichment of carboxylic acid compounds and PAHs. The new sorbent exhibited high extraction efficiency towards the tested compounds and the results show that such a sorbent can offer multiple intermolecular interactions: electrostatic, π-π, and hydrophobic interactions. Several parameters affecting the extraction recovery, such as the pH of sample solution, the pH of eluent, the solubility of eluent, the volume of eluent, and sample loading, were also investigated. Under the optimized conditions, the proposed method was applied to the analysis of four carboxylic acid compounds and four PAHs in environmental water samples. Good linearities were obtained for all the tested compounds with R(2) larger than 0.9903. The limits of detection were found to be in the range of 0.0065-0.5 μg L(-1). The recovery values of spiked river water samples were from 63.2% to 112.3% with relative standard deviations (RSDs) less than 10.1% (n = 4).

Protection by imidazol(ine) drugs and agmatine of glutamate-induced neurotoxicity in cultured cerebellar granule cells through blockade of NMDA receptor.

Science.gov (United States)

Olmos, G; DeGregorio-Rocasolano, N; Paz Regalado, M; Gasull, T; Assumpció Boronat, M; Trullas, R; Villarroel, A; Lerma, J; García-Sevilla, J A

1999-07-01

This study was designed to assess the potential neuroprotective effect of several imidazol(ine) drugs and agmatine on glutamate-induced necrosis and on apoptosis induced by low extracellular K+ in cultured cerebellar granule cells. Exposure (30 min) of energy deprived cells to L-glutamate (1-100 microM) caused a concentration-dependent neurotoxicity, as determined 24 h later by a decrease in the ability of the cells to metabolize 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) into a reduced formazan product. L-glutamate-induced neurotoxicity (EC50=5 microM) was blocked by the specific NMDA receptor antagonist MK-801 (dizocilpine). Imidazol(ine) drugs and agmatine fully prevented neurotoxicity induced by 20 microM (EC100) L-glutamate with the rank order (EC50 in microM): antazoline (13)>cirazoline (44)>LSL 61122 [2-styryl-2-imidazoline] (54)>LSL 60101 [2-(2-benzofuranyl) imidazole] (75)>idazoxan (90)>LSL 60129 [2-(1,4-benzodioxan-6-yl)-4,5-dihydroimidazole](101)>RX82 1002 (2-methoxy idazoxan) (106)>agmatine (196). No neuroprotective effect of these drugs was observed in a model of apoptotic neuronal cell death (reduction of extracellular K+) which does not involve stimulation of NMDA receptors. Imidazol(ine) drugs and agmatine fully inhibited [3H]-(+)-MK-801 binding to the phencyclidine site of NMDA receptors in rat brain. The profile of drug potency protecting against L-glutamate neurotoxicity correlated well (r=0.90) with the potency of the same compounds competing against [3H]-(+)-MK-801 binding. In HEK-293 cells transfected to express the NR1-1a and NR2C subunits of the NMDA receptor, antazoline and agmatine produced a voltage- and concentration-dependent block of glutamate-induced currents. Analysis of the voltage dependence of the block was consistent with the presence of a binding site for antazoline located within the NMDA channel pore with an IC50 of 10-12 microM at 0 mV. It is concluded that imidazol(ine) drugs and agmatine are

Green synthesis of novel quinoline based imidazole derivatives and evaluation of their antimicrobial activity

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N.C. Desai

2014-12-01

Full Text Available We have described the conventional and microwave method for the synthesis of N-(4-((2-chloroquinolin-3-ylmethylene-5-oxo-2-phenyl-4,5-dihydro-1H-imidazol-1-yl(arylamides 3a–l. It is observed that the solvent-free microwave thermolysis is a convenient, rapid, high-yielding, and environmental friendly protocol for the synthesis of quinoline based imidazole derivatives when compared with conventional reaction in a solution phase. Antimicrobial activity of the newly synthesized compounds is screened in vitro on the following microbial cultures: Escherichia coli (MTCC 443, Pseudomonas aeruginosa (MTCC 1688, Staphylococcus aureus (MTCC 96, Streptococcus pyogenes (MTCC 442, Candida albicans (MTCC 227, Aspergillus niger (MTCC 282, Aspergillus clavatus (MTCC 1323. All the synthesized bio-active molecules are tested for their in vitro antimicrobial activity by bioassay namely serial broth dilution. Among these compounds 3c, 3d, 3f, 3h and 3j show significant potency against different microbial strains. All the compounds have been characterized by IR, 1H NMR, 13C NMR and mass spectral data. On the basis of statistical analysis, it is observed that these compounds give significant co-relation.

Synthesis and DNA-binding study of imidazole linked thiazolidinone derivatives.

Science.gov (United States)

War, Javeed Ahmad; Srivastava, Santosh Kumar; Srivastava, Savitri Devi

2017-02-01

A novel series of imidazole-linked thiazolidinone hybrid molecules were designed and synthesized through a feasible synthetic protocol. The molecules were characterized with Fourier transform infrared (FT-IR), 1 H nuclear magnetic resonance (NMR), 13 C NMR and high-resolution mass spectrometry (HRMS) techniques. In vitro susceptibility tests against Gram-positive (S. aureus and B. subtilis) and Gram-negative bacteria (E. coli and P. aeruginosa) gave highly promising results. The most active molecule (3e) gave a minimal inhibitory concentration (MIC) value of 3.125 μg/mL which is on par with the reference drug streptomycin. Structure-activity relationships revealed activity enhancement by nitro and chloro groups when they occupied meta position of the arylidene ring in 2-((3-(imidazol-1-yl)propyl)amino)-5-benzylidenethiazolidin-4-ones. DNA-binding study of the most potent molecule 3e with salmon milt DNA (sm-DNA) under simulated physiological pH was probed with UV-visible absorption, fluorescence quenching, gel electrophoresis and molecular docking techniques. These studies established that compound 3e has a strong affinity towards DNA and binds at DNA minor groove with a binding constant (K b ) 0.18 × 10 2  L mol -1 . Molecular docking simulations predicted strong affinity of 3e towards DNA with a binding affinity (ΔG) -8.5 kcal/mol. Van der Waals forces, hydrogen bonding and hydrophobic interactions were predicted as the main forces of interaction. The molecule 3e exhibited specific affinity towards adenine-thiamine base pairs. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Endosomal Escape and Delivery of CRISPR/Cas9 Genome Editing Machinery Enabled by Nanoscale Zeolitic Imidazolate Framework

KAUST Repository

Alsaiari, Shahad K.

2017-12-22

CRISPR/Cas9 is a combined protein (Cas9) and an engineered single guide RNA (sgRNA) genome editing platform that offers revolutionary solutions to genetic diseases. It has, however, a double delivery problem owning to the large protein size and the highly charged RNA component. In this work, we report the first example of CRISPR/Cas9 encapsulated by nanoscale zeolitic imidazole frameworks (ZIFs) with a loading efficiency of 17% and enhanced endosomal escape promoted by the protonated imidazole moieties. The gene editing potential of CRISPR/Cas9 encapsulated by ZIF-8 (CC-ZIFs) is further verified by knocking down the gene expression of green fluorescent protein by 37% over 4 days employing CRISPR/Cas9 machinery. The nanoscale CC-ZIFs are biocompatible and easily scaled-up offering excellent loading capacity and controlled co-delivery of intact Cas9 protein and sgRNA.

Endosomal Escape and Delivery of CRISPR/Cas9 Genome Editing Machinery Enabled by Nanoscale Zeolitic Imidazolate Framework

KAUST Repository

Alsaiari, Shahad K.; Patil, Sachin; Alyami, Mram Z.; Alamoudi, Kholod; Aleisa, Fajr A; Merzaban, Jasmeen; Li, Mo; Khashab, Niveen M.

2017-01-01

CRISPR/Cas9 is a combined protein (Cas9) and an engineered single guide RNA (sgRNA) genome editing platform that offers revolutionary solutions to genetic diseases. It has, however, a double delivery problem owning to the large protein size and the highly charged RNA component. In this work, we report the first example of CRISPR/Cas9 encapsulated by nanoscale zeolitic imidazole frameworks (ZIFs) with a loading efficiency of 17% and enhanced endosomal escape promoted by the protonated imidazole moieties. The gene editing potential of CRISPR/Cas9 encapsulated by ZIF-8 (CC-ZIFs) is further verified by knocking down the gene expression of green fluorescent protein by 37% over 4 days employing CRISPR/Cas9 machinery. The nanoscale CC-ZIFs are biocompatible and easily scaled-up offering excellent loading capacity and controlled co-delivery of intact Cas9 protein and sgRNA.

Synthesis and Characterization of New Silver (I N-Heterocyclic Ccarbene Ccomplex Dderived from Imidazol-2-ylidene salt

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Mohammedl Mujbe Hasson

2018-04-01

Full Text Available A new N, N'-imidazolium salt 1-(2,6-diisopropylphenyl-3- (4,6-dimorpholino -1,3,5-traizine-2-yl-1H-imidazol-3-ium chloride as a precursor of N - heterocyclic carbene ligand was prepared via the reaction of 1 - (2, 6 - diisopropyl phenyl - 1H - imidazole with 1, 3, 5 - triazine derivative bearing morpholine substituent (2, 6 -dimorpholine - 6- chloro-1, 3, 5-triaziazine. Linear coordi-nated Ag (І NHC complex was synthesised via deprotonation of the imidazolium salt and reac-tion with Ag2O in darkness at room temperature by in situ method. The complex was synthesised for using as transfer agent to prepare another transition metals complexes by transmetallation method in the future. The imidazolium salt and their silver complex have been characterized by 1 H and 13C NMR spectroscopy as well as mass spectrometry.

Synthesis and spectroscopic characterization of Y-shaped fluorophores with an imidazole core containing crown ether moieties

Energy Technology Data Exchange (ETDEWEB)

Doğru, Ümit; Öztürk Ürüt, Gülsiye, E-mail: gulsiye.ozturk@deu.edu.tr; Bayramin, Dilek

2015-07-15

In this study three new Y-shaped fluorophores, 4,5-(2,2'-diphenyl)vinyl-{2-[(1,4,7,10-tetraoxa-13-azacyclopentadecyl) phenyl]}-1H-imidazole (1a), 4,5-{[2,2'-bis(4-methoxyphenyl)vinyl]-[2-(1,4,7,10-tetraoxa-13- azacyclopentadecyl)-phenyl]}-1H-imidazole (1b) and 4,5-(2,2'-diphenyl)vinyl-{2-(1,4,7,10,13-benzopentaoxacyclopentadecyl)} -1H-imidazole (1c) were synthesized. 1,6-Diphenylhexa-1,5-diene-3,4-dione (2a) and 1,6-bis(4-methoxyphenyl)hexa-1,5-diene-3,4-dione (2b) were synthesized as preliminary fluorophores and then reacted with 4-formylbenzo-aza-15-crown-5 (3a) and 4-formylbenzo-15-crown-5 (3b) to obtain the three Y-shaped fluorophores 1a, 1b and 1c. 4-formylbenzo-aza-15-crown-5 and 4-formylbenzo-15-crown-5 intermediates were synthesized with Vilsmeier–Haack reaction. The photophysical properties such as maximum absorption wavelengths, maximum emission wavelengths, Stokes' shifts, singlet energies, fluorescence quantum yields and photostabilities of the compounds were investigated by measuring absorption and emission spectra in a series of solvents of varying polarities of toluene (TOL), dichloromethane (DCM), tetrahydrofuran (THF), ethyl acetate (EA), acetonitrile (ACN), and N,N-dimethylformamide (DMF). The three compounds 1a, 1b and 1c exhibited emission maxima in the 412–677 nm range. All the derivatives synthesized exhibited excellent photostability in all the solvents tested. - Highlights: • Three new Y-shaped fluorophores were synthesized for the first time. • Their absorption and emission properties were investigated. • All the derivatives synthesized exhibited excellent photostability.

Synthesis and spectroscopic characterization of Y-shaped fluorophores with an imidazole core containing crown ether moieties

International Nuclear Information System (INIS)

Doğru, Ümit; Öztürk Ürüt, Gülsiye; Bayramin, Dilek

2015-01-01

In this study three new Y-shaped fluorophores, 4,5-(2,2'-diphenyl)vinyl-{2-[(1,4,7,10-tetraoxa-13-azacyclopentadecyl) phenyl]}-1H-imidazole (1a), 4,5-{[2,2'-bis(4-methoxyphenyl)vinyl]-[2-(1,4,7,10-tetraoxa-13- azacyclopentadecyl)-phenyl]}-1H-imidazole (1b) and 4,5-(2,2'-diphenyl)vinyl-{2-(1,4,7,10,13-benzopentaoxacyclopentadecyl)} -1H-imidazole (1c) were synthesized. 1,6-Diphenylhexa-1,5-diene-3,4-dione (2a) and 1,6-bis(4-methoxyphenyl)hexa-1,5-diene-3,4-dione (2b) were synthesized as preliminary fluorophores and then reacted with 4-formylbenzo-aza-15-crown-5 (3a) and 4-formylbenzo-15-crown-5 (3b) to obtain the three Y-shaped fluorophores 1a, 1b and 1c. 4-formylbenzo-aza-15-crown-5 and 4-formylbenzo-15-crown-5 intermediates were synthesized with Vilsmeier–Haack reaction. The photophysical properties such as maximum absorption wavelengths, maximum emission wavelengths, Stokes' shifts, singlet energies, fluorescence quantum yields and photostabilities of the compounds were investigated by measuring absorption and emission spectra in a series of solvents of varying polarities of toluene (TOL), dichloromethane (DCM), tetrahydrofuran (THF), ethyl acetate (EA), acetonitrile (ACN), and N,N-dimethylformamide (DMF). The three compounds 1a, 1b and 1c exhibited emission maxima in the 412–677 nm range. All the derivatives synthesized exhibited excellent photostability in all the solvents tested. - Highlights: • Three new Y-shaped fluorophores were synthesized for the first time. • Their absorption and emission properties were investigated. • All the derivatives synthesized exhibited excellent photostability

Cepheids Geometrical Distances Using Space Interferometry

Science.gov (United States)

Marengo, M.; Karovska, M.; Sasselov, D. D.; Sanchez, M.

2004-05-01

A space based interferometer with a sub-milliarcsecond resolution in the UV-optical will provide a new avenue for the calibration of primary distance indicators with unprecedented accuracy, by allowing very accurate and stable measurements of Cepheids pulsation amplitudes at wavelengths not accessible from the ground. Sasselov & Karovska (1994) have shown that interferometers allow very accurate measurements of Cepheids distances by using a ``geometric'' variant of the Baade-Wesselink method. This method has been succesfully applied to derive distances and radii of nearby Cepheids using ground-based near-IR and optical interferometers, within a 15% accuracy level. Our study shows that the main source of error in these measurements is due to the perturbing effects of the Earth atmosphere, which is the limiting factor in the interferometer stability. A space interferometer will not suffer from this intrinsic limitations, and can potentially lead to improve astronomical distance measurements by an order of magnitude in precision. We discuss here the technical requirements that a space based facility will need to carry out this project, allowing distance measurements within a few percent accuracy level. We will finally discuss how a sub-milliarcsecond resolution will allow the direct distance determination for hundreds of galactic sources, and provide a substantial improvement in the zero-point of the Cepheid distance scale.

Magnitude And Distance Determination From The First Few Seconds Of One Three Components Seismological Station Signal Using Support Vector Machine Regression Methods

Science.gov (United States)

Ochoa Gutierrez, L. H.; Vargas Jimenez, C. A.; Niño Vasquez, L. F.

2011-12-01

The "Sabana de Bogota" (Bogota Savannah) is the most important social and economical center of Colombia. Almost the third of population is concentrated in this region and generates about the 40% of Colombia's Internal Brute Product (IBP). According to this, the zone presents an elevated vulnerability in case that a high destructive seismic event occurs. Historical evidences show that high magnitude events took place in the past with a huge damage caused to the city and indicate that is probable that such events can occur in the next years. This is the reason why we are working in an early warning generation system, using the first few seconds of a seismic signal registered by three components and wide band seismometers. Such system can be implemented using Computational Intelligence tools, designed and calibrated to the particular Geological, Structural and environmental conditions present in the region. The methods developed are expected to work on real time, thus suitable software and electronic tools need to be developed. We used Support Vector Machines Regression (SVMR) methods trained and tested with historic seismic events registered by "EL ROSAL" Station, located near Bogotá, calculating descriptors or attributes as the input of the model, from the first 6 seconds of signal. With this algorithm, we obtained less than 10% of mean absolute error and correlation coefficients greater than 85% in hypocentral distance and Magnitude estimation. With this results we consider that we can improve the method trying to have better accuracy with less signal time and that this can be a very useful model to be implemented directly in the seismological stations to generate a fast characterization of the event, broadcasting not only raw signal but pre-processed information that can be very useful for accurate Early Warning Generation.

Quantification of liver fat in the presence of iron overload.

Science.gov (United States)

Horng, Debra E; Hernando, Diego; Reeder, Scott B

2017-02-01

To evaluate the accuracy of R2* models (1/T 2 * = R2*) for chemical shift-encoded magnetic resonance imaging (CSE-MRI)-based proton density fat-fraction (PDFF) quantification in patients with fatty liver and iron overload, using MR spectroscopy (MRS) as the reference standard. Two Monte Carlo simulations were implemented to compare the root-mean-squared-error (RMSE) performance of single-R2* and dual-R2* correction in a theoretical liver environment with high iron. Fatty liver was defined as hepatic PDFF >5.6% based on MRS; only subjects with fatty liver were considered for analyses involving fat. From a group of 40 patients with known/suspected iron overload, nine patients were identified at 1.5T, and 13 at 3.0T with fatty liver. MRS linewidth measurements were used to estimate R2* values for water and fat peaks. PDFF was measured from CSE-MRI data using single-R2* and dual-R2* correction with magnitude and complex fitting. Spectroscopy-based R2* analysis demonstrated that the R2* of water and fat remain close in value, both increasing as iron overload increases: linear regression between R2* W and R2* F resulted in slope = 0.95 [0.79-1.12] (95% limits of agreement) at 1.5T and slope = 0.76 [0.49-1.03] at 3.0T. MRI-PDFF using dual-R2* correction had severe artifacts. MRI-PDFF using single-R2* correction had good agreement with MRS-PDFF: Bland-Altman analysis resulted in -0.7% (bias) ± 2.9% (95% limits of agreement) for magnitude-fit and -1.3% ± 4.3% for complex-fit at 1.5T, and -1.5% ± 8.4% for magnitude-fit and -2.2% ± 9.6% for complex-fit at 3.0T. Single-R2* modeling enables accurate PDFF quantification, even in patients with iron overload. 1 J. Magn. Reson. Imaging 2017;45:428-439. © 2016 International Society for Magnetic Resonance in Medicine.

A mesoscale iron enrichment in the western subarctic Pacific induces a large centric diatom bloom.

Science.gov (United States)

Tsuda, Atsushi; Takeda, Shigenobu; Saito, Hiroaki; Nishioka, Jun; Nojiri, Yukihiro; Kudo, Isao; Kiyosawa, Hiroshi; Shiomoto, Akihiro; Imai, Keiri; Ono, Tsuneo; Shimamoto, Akifumi; Tsumune, Daisuke; Yoshimura, Takeshi; Aono, Tatsuo; Hinuma, Akira; Kinugasa, Masatoshi; Suzuki, Koji; Sohrin, Yoshiki; Noiri, Yoshifumi; Tani, Heihachiro; Deguchi, Yuji; Tsurushima, Nobuo; Ogawa, Hiroshi; Fukami, Kimio; Kuma, Kenshi; Saino, Toshiro

2003-05-09

We have performed an in situ test of the iron limitation hypothesis in the subarctic North Pacific Ocean. A single enrichment of dissolved iron caused a large increase in phytoplankton standing stock and decreases in macronutrients and dissolved carbon dioxide. The dominant phytoplankton species shifted after the iron addition from pennate diatoms to a centric diatom, Chaetoceros debilis, that showed a very high growth rate, 2.6 doublings per day. We conclude that the bioavailability of iron regulates the magnitude of the phytoplankton biomass and the key phytoplankton species that determine the biogeochemical sensitivity to iron supply of high-nitrate, low-chlorophyll waters.

Impact of source terms on distances to which reactor accident consequences occur

International Nuclear Information System (INIS)

Ostmeyer, R.M.

1982-01-01

Estimates of the distances over which reactor accident consequences might occur are important for development of siting criteria and for emergency response planning. This paper summarizes the results of a series of CRAC2 calculations performed to estimate these distances. Because of the current controversy concerning the magnitude of source terms for severe accidents, the impact of source term reductions upon distance estimates is also examined

A Submarine Journey: The Pyrrole-Imidazole Alkaloids

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Alessandra Scolaro

2009-11-01

Full Text Available In his most celebrated tale “The Picture of Dorian Gray”, Oscar Wilde stated that “those who go beneath the surface do so at their peril”. This sentence could be a prophetical warning for the practitioner who voluntarily challenges himself with trying to synthesize marine sponge-deriving pyrrole-imidazole alkaloids. This now nearly triple-digit membered community has been growing exponentially in the last 20 years, both in terms of new representatives and topological complexity − from simple, achiral oroidin to the breathtaking 12-ring stylissadines A and B, each possessing 16 stereocenters. While the biosynthesis and the role in the sponge economy of most of these alkaloids still lies in the realm of speculations, significant biological activities for some of them have clearly emerged. This review will account for the progress in achieving the total synthesis of the more biologically enticing members of this class of natural products.

THE LEO IV DWARF SPHEROIDAL GALAXY: COLOR-MAGNITUDE DIAGRAM AND PULSATING STARS

International Nuclear Information System (INIS)

Moretti, Maria Ida; Dall'Ora, Massimo; Ripepi, Vincenzo

2009-01-01

We present the first V, B - V color-magnitude diagram of the Leo IV dwarf spheroidal galaxy, a faint Milky Way satellite recently discovered by the Sloan Digital Sky Survey. We have obtained B, V time-series photometry reaching about half a magnitude below the Leo IV turnoff, which we detect at V = 24.7 mag, and have performed the first study of the variable star population. We have identified three RR Lyrae stars (all fundamental-mode pulsators, RRab) and one SX Phoenicis variable in the galaxy. In the period-amplitude diagram the Leo IV RR Lyrae stars are located close to the loci of Oosterhoff type I systems and the evolved fundamental-mode RR Lyrae stars in the Galactic globular cluster M3. However, their mean pulsation period, (Pab) = 0.655 days, would suggest an Oosterhoff type II classification for this galaxy. The RR Lyrae stars trace very well the galaxy's horizontal branch, setting its average magnitude at (V RR ) = 21.48 ± 0.03 mag (standard deviation of the mean). This leads to a distance modulus of μ 0 = 20.94 ± 0.07 mag, corresponding to a distance of 154 ± 5 kpc, by adopting for the Leo IV dSph a reddening E(B - V) = 0.04 ± 0.01 mag and a metallicity of [Fe/H] = -2.31 ± 0.10.

DFT study on the standard electrode potentials of imidazole, tetrathiafulvalene, and tetrathiafulvalene-imidazole.

Science.gov (United States)

Tugsuz, Tugba

2010-12-30

Extensive DFT calculations on the standard electrode potentials of imidazole (Im), tetrathiafulvalene (TTF), and 2-, 4-, and 5-TTF-Im were carried out. Geometries and Gibbs free energies of H-bonded dimer, anion, protonated cation, and neutral structures of Im, mono- and dication, and neutral structures of TTF in gas and acetonitrile solvent were computed by using 10 hybrid density functionals (B3LYP, TPSSH, PBEH1PBE, M06, M062X, X3LYP, BMK, B1B95, M05, M052X) combined with the TZVP basis set. CPCM and SMD solvation models were applied to predict the Gibbs free energies of molecules in acetonitrile solvent. Frequency calculations were carried out for all structures, and none of them has been found to exhibit any imaginary frequency. Finally, the BMK hybrid functional was selected for computation of the standard electrode potential of TTF-Im, because it gives the most accurate values in both Im and TTF, differing by 0.05 V from the experimental ones. Moreover, frequencies from the BMK functional are reasonably close to the experimental ones. The standard electrode potentials of 2-, 4-, and 5-TTF-Im predicted for two-electron oxidation are 0.946, 0.870, and 0.839 V in CPCM and 0.927, 0.866, and 0.824 V in SMD. For one-electron oxidation these are 0.491, 0.421, and 0.400 V in CPCM and 0.476, 0.377, and 0.360 V in SMD, respectively.

All-Sky Spectrally Matched UBVRI - ZY and u‧ g‧ r‧ i‧ z‧ Magnitudes for Stars in the Tycho2 Catalog

Science.gov (United States)

Pickles, A.; Depagne, É.

2010-12-01

We present fitted UBVRI - ZY and u‧ g‧ r‧ i‧ z‧ magnitudes, spectral types, and distances for 2.4 million stars, derived from synthetic photometry of a library spectrum that best matches the Tycho2 BT VT, NOMAD RN, and 2MASS JHK2/S catalog magnitudes. We present similarly synthesized multifilter magnitudes, types, and distances for 4.8 million stars with 2MASS and SDSS photometry to g digital images with fields of view of 0.5° or more. Using several such standards per field, automatic flux calibration can be achieved to a few percent in any filter, at any air mass, in most workable observing conditions, to facilitate intercomparison of data from different sites, telescopes, and instruments.

Near-IR TRGB Distance Modulus of Dwarf Irregular Galaxy IC 1613

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M. Y. Jung

2009-12-01

Full Text Available The JHKs magnitudes of the red giant branch tip (TRGB and the distance moduli of the nearby dwarf irregular galaxy IC 1613 have been determined from the nearinfrared luminosity functions (LFs of the resolved stars in the galaxy. Applying a Savitzky-Golay filtering, we derived the second derivatives of the LFs, and estimated the apparent magnitudes of the TRGB as mJ = 19.1, mH = 18.4, and mKs = 18:0. The mean values of the theoretical absolute magnitudes of the TRGB were measured by using the Yonsei-Yale isochrones with a metallicity range of -2.1 < [Fe/H] < -0.5 and age of 12 Gyr. The derived values of near-infrared TRGB distance moduli for IC 1613 are (m-M = 24.12±0:25, 24.20±0.44, and 24.00±0.52 for J;H, and Ks bands, respectively.

Teleseismic magnitude relations

Directory of Open Access Journals (Sweden)

Markus Båth

2010-02-01

Full Text Available Using available sets of magnitude determinations, primarily from Uppsala seismological bulletin, various extensions are made of the Zurich magnitude recommendations of 1967. Thus, body-wave magnitude (m and surface-wave magnitudes (M are related to each other for 12 different earthquake regions as well as world-wide. Depth corrections for M are derived for all focal depths. Formulas are developed which permit calculation of M also from vertical component long-period seismographs. Body-wave magnitudes from broad-band and narrow-band short-period seismographs are compared and relations deduced. Applications are made both to underground nuclear explosions and to earthquakes. The possibilities of explosion-earthquake discrimination on the basis of magnitudes are examined, as well as the determination of explosive yield from magnitudes. For earthquakes, relations between magnitudes of main earthquakes and largest aftershocks are investigated. A world-wide station network for more homogeneous magnitude determinations is suggested in order to provide the necessary reference system.

Relics of short distance effects for the neutron electric dipole moment

International Nuclear Information System (INIS)

Eeg, J.O.

1982-12-01

The Feynman diagrams which dominate the estimates of the electric dipole moment of the neutron with Kobayashi-Maskawa CP violation are considered. The extracted long distance contributions and the relics of short distance contributions are shown to be complementary and of the same magnitude, resulting in mod(Dsub(n)/e) approximately = (10 - 31 - 10 - 30 ) cm. (Auth.)

Adsorbed States of phosphonate derivatives of N-heterocyclic aromatic compounds, imidazole, thiazole, and pyridine on colloidal silver: comparison with a silver electrode.

Science.gov (United States)

Podstawka, Edyta; Olszewski, Tomasz K; Boduszek, Bogdan; Proniewicz, Leonard M

2009-09-03

Here, we report a systematic surface-enhanced Raman spectroscopy (SERS) study of the structures of phosphonate derivatives of the N-heterocyclic aromatic compounds imidazole (ImMeP ([hydroxy(1H-imidazol-5-yl)methyl]phosphonic acid) and (ImMe)(2)P (bis[hydroxy-(1H-imidazol-4-yl)-methyl]phosphinic acid)), thiazole (BAThMeP (butylaminothiazol-2-yl-methyl)phosphonic acid) and BzAThMeP (benzylaminothiazol-2-yl-methyl)phosphonic acid)), and pyridine ((PyMe)(2)P (bis[(hydroxypyridin-3-yl-methyl)]phosphinic acid)) adsorbed on nanometer-sized colloidal particles. We compared these structures to those on a roughened silver electrode surface to determine the relationship between the adsorption strength and the geometry. For example, we showed that all of these biomolecules interact with the colloidal surface through aromatic rings. However, for BzAThMeP, a preferential interaction between the benzene ring and the colloidal silver surface is observed more so than that between the thiazole ring and this substrate. The PC(OH)C fragment does not take part in the adsorption process, and the phosphonate moiety of ImMeP and (ImMe)(2)P, being removed from the surface, only assists in this process.

Water oxidation catalyzed by molecular di- and nonanuclear Fe complexes: importance of a proper ligand framework.

Science.gov (United States)

Das, Biswanath; Lee, Bao-Lin; Karlsson, Erik A; Åkermark, Torbjörn; Shatskiy, Andrey; Demeshko, Serhiy; Liao, Rong-Zhen; Laine, Tanja M; Haukka, Matti; Zeglio, Erica; Abdel-Magied, Ahmed F; Siegbahn, Per E M; Meyer, Franc; Kärkäs, Markus D; Johnston, Eric V; Nordlander, Ebbe; Åkermark, Björn

2016-09-14

The synthesis of two molecular iron complexes, a dinuclear iron(iii,iii) complex and a nonanuclear iron complex, based on the dinucleating ligand 2,2'-(2-hydroxy-5-methyl-1,3-phenylene)bis(1H-benzo[d]imidazole-4-carboxylic acid) is described. The two iron complexes were found to drive the oxidation of water by the one-electron oxidant [Ru(bpy)3](3+).

SOFTWARE FOR IMAGE PROCESSING OF IRON-CARBONACEOUS ALLOY MICROSTRUCTURES

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A. N. Chichko

2011-01-01

Full Text Available The paper proposes a mathematical apparatus for image processing of a cast-iron microstructure of a pearlite class that has casually distributed graphite inclusions in the structure the software has been developed and it allows to determine statistical functions concerning distribution of graphite inclusion characteristics according to areas, perimeters and distances between inclusions. The paper shows that computer processing of gray pig-iron microstructure image makes it possible to classify microstructures on the basis of statistical distribution of a graphite phase which are considered as indiscernible while applying conventional metallographic methods and it has practical significance for investigation of the interrelations – «workability – cast iron microstructure».

Gas-Phase Thermal Tautomerization of Imidazole-Acetic Acid: Theoretical and Computational Investigations

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Saadullah G. Aziz

2015-11-01

Full Text Available The gas-phase thermal tautomerization reaction between imidazole-4-acetic (I and imidazole-5-acetic (II acids was monitored using the traditional hybrid functional (B3LYP and the long-range corrected functionals (CAM-B3LYP and ωB97XD with 6-311++G** and aug-cc-pvdz basis sets. The roles of the long-range and dispersion corrections on their geometrical parameters, thermodynamic functions, kinetics, dipole moments, Highest Occupied Molecular Orbital–Lowest Unoccupied Molecular Orbital (HOMO–LUMO energy gaps and total hyperpolarizability were investigated. All tested levels of theory predicted the preference of I over II by 0.750–0.877 kcal/mol. The origin of predilection of I is assigned to the H-bonding interaction (nN8→σ*O14–H15. This interaction stabilized I by 15.07 kcal/mol. The gas-phase interconversion between the two tautomers assumed a 1,2-proton shift mechanism, with two transition states (TS, TS1 and TS2, having energy barriers of 47.67–49.92 and 49.55–52.69 kcal/mol, respectively, and an sp3-type intermediate. A water-assisted 1,3-proton shift route brought the barrier height down to less than 20 kcal/mol in gas-phase and less than 12 kcal/mol in solution. The relatively high values of total hyperpolarizability of I compared to II were interpreted and discussed.

Comparing soluble ferric pyrophosphate to common iron salts and chelates as sources of bioavailable iron in a Caco-2 cell culture model.

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Zhu, Le; Glahn, Raymond P; Nelson, Deanna; Miller, Dennis D

2009-06-10

Iron bioavailability from supplements and fortificants varies depending upon the form of the iron and the presence or absence of iron absorption enhancers and inhibitors. Our objectives were to compare the effects of pH and selected enhancers and inhibitors and food matrices on the bioavailability of iron in soluble ferric pyrophosphate (SFP) to other iron fortificants using a Caco-2 cell culture model with or without the combination of in vitro digestion. Ferritin formation was the highest in cells treated with SFP compared to those treated with other iron compounds or chelates. Exposure to pH 2 followed by adjustment to pH 7 markedly decreased FeSO(4) bioavailability but had a smaller effect on bioavailabilities from SFP and sodium iron(III) ethylenediaminetetraacetate (NaFeEDTA), suggesting that chelating agents minimize the effects of pH on iron bioavailability. Adding ascorbic acid (AA) and cysteine to SFP in a 20:1 molar ratio increased ferritin formation by 3- and 2-fold, respectively, whereas adding citrate had no significant effect on the bioavailability of SFP. Adding phytic acid (10:1) and tannic acid (1:1) to iron decreased iron bioavailability from SFP by 91 and 99%, respectively. The addition of zinc had a marked inhibitory effect on iron bioavailability. Calcium and magnesium also inhibited iron bioavailability but to a lesser extent. Incorporating SFP in rice greatly reduced iron bioavailability from SFP, but this effect can be partially reversed with the addition of AA. SFP and FeSO(4) were taken up similarly when added to nonfat dry milk. Our results suggest that dietary factors known to enhance and inhibit iron bioavailability from various iron sources affect iron bioavailability from SFP in similar directions. However, the magnitude of the effects of iron absorption inhibitors on SFP iron appears to be smaller than on iron salts, such as FeSO(4) and FeCl(3). This supports the hypothesis that SFP is a promising iron source for food fortification

Scaling relations of moment magnitude, local magnitude, and duration magnitude for earthquakes originated in northeast India

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Bora, Dipok K.

2016-06-01

In this study, we aim to improve the scaling between the moment magnitude ( M W), local magnitude ( M L), and the duration magnitude ( M D) for 162 earthquakes in Shillong-Mikir plateau and its adjoining region of northeast India by extending the M W estimates to lower magnitude earthquakes using spectral analysis of P-waves from vertical component seismograms. The M W- M L and M W- M D relationships are determined by linear regression analysis. It is found that, M W values can be considered consistent with M L and M D, within 0.1 and 0.2 magnitude units respectively, in 90 % of the cases. The scaling relationships investigated comply well with similar relationships in other regions in the world and in other seismogenic areas in the northeast India region.

Nitric oxide and plant iron homeostasis.

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Buet, Agustina; Simontacchi, Marcela

2015-03-01

Like all living organisms, plants demand iron (Fe) for important biochemical and metabolic processes. Internal imbalances, as a consequence of insufficient or excess Fe in the environment, lead to growth restriction and affect crop yield. Knowledge of signals and factors affecting each step in Fe uptake from the soil and distribution (long-distance transport, remobilization from old to young leaves, and storage in seeds) is necessary to improve our understanding of plant mineral nutrition. In this context, the role of nitric oxide (NO) is discussed as a key player in maintaining Fe homeostasis through its cross talk with hormones, ferritin, and frataxin and the ability to form nitrosyl-iron complexes. © 2015 New York Academy of Sciences.

How Deep Is Your SNARC? Interactions Between Numerical Magnitude, Response Hands, and Reachability in Peripersonal Space

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Johannes Lohmann

2018-05-01

Full Text Available Spatial, physical, and semantic magnitude dimensions can influence action decisions in human cognitive processing and interact with each other. For example, in the spatial-numerical associations of response code (SNARC effect, semantic numerical magnitude facilitates left-hand or right-hand responding dependent on the small or large magnitude of number symbols. SNARC-like interactions of numerical magnitudes with the radial spatial dimension (depth were postulated from early on. Usually, the SNARC effect in any direction is investigated using fronto-parallel computer monitors for presentation of stimuli. In such 2D setups, however, the metaphorical and literal interpretation of the radial depth axis with seemingly close/far stimuli or responses are not distinct. Hence, it is difficult to draw clear conclusions with respect to the contribution of different spatial mappings to the SNARC effect. In order to disentangle the different mappings in a natural way, we studied parametrical interactions between semantic numerical magnitude, horizontal directional responses, and perceptual distance by means of stereoscopic depth in an immersive virtual reality (VR. Two VR experiments show horizontal SNARC effects across all spatial displacements in traditional latency measures and kinematic response parameters. No indications of a SNARC effect along the depth axis, as it would be predicted by a direct mapping account, were observed, but the results show a non-linear relationship between horizontal SNARC slopes and physical distance. Steepest SNARC slopes were observed for digits presented close to the hands. We conclude that spatial-numerical processing is susceptible to effector-based processes but relatively resilient to task-irrelevant variations of radial-spatial magnitudes.

How Deep Is Your SNARC? Interactions Between Numerical Magnitude, Response Hands, and Reachability in Peripersonal Space.

Science.gov (United States)

Lohmann, Johannes; Schroeder, Philipp A; Nuerk, Hans-Christoph; Plewnia, Christian; Butz, Martin V

2018-01-01

Spatial, physical, and semantic magnitude dimensions can influence action decisions in human cognitive processing and interact with each other. For example, in the spatial-numerical associations of response code (SNARC) effect, semantic numerical magnitude facilitates left-hand or right-hand responding dependent on the small or large magnitude of number symbols. SNARC-like interactions of numerical magnitudes with the radial spatial dimension (depth) were postulated from early on. Usually, the SNARC effect in any direction is investigated using fronto-parallel computer monitors for presentation of stimuli. In such 2D setups, however, the metaphorical and literal interpretation of the radial depth axis with seemingly close/far stimuli or responses are not distinct. Hence, it is difficult to draw clear conclusions with respect to the contribution of different spatial mappings to the SNARC effect. In order to disentangle the different mappings in a natural way, we studied parametrical interactions between semantic numerical magnitude, horizontal directional responses, and perceptual distance by means of stereoscopic depth in an immersive virtual reality (VR). Two VR experiments show horizontal SNARC effects across all spatial displacements in traditional latency measures and kinematic response parameters. No indications of a SNARC effect along the depth axis, as it would be predicted by a direct mapping account, were observed, but the results show a non-linear relationship between horizontal SNARC slopes and physical distance. Steepest SNARC slopes were observed for digits presented close to the hands. We conclude that spatial-numerical processing is susceptible to effector-based processes but relatively resilient to task-irrelevant variations of radial-spatial magnitudes.

Directly oxidized chemiluminescence of 2-substituted-4,5-di(2-furyl)-1H -imidazole by acidic potassium permanganate and its analytical application for determination of albumin.

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Kang, Jing; Zhang, Yumin; Huang, Zhongxiu; Han, Lu; Tang, Jieli; Wang, Shuaijun; Zhang, Yihua

2011-07-01

In the paper, 2,4,5-tri(2-furyl)-1H-imidazole (TFI) and 2-phenyl-4,5-di(2-furyl)-1H-imidazole (PDFI), were chosen to investigate chemiluminescence (CL) properties of 2-substituted-4,5-di(2-furyl)-1H-imidazoles. The directly oxidized CL of analytes by potassium permanganate (KMnO(4)) was in detail studied. The KMnO(4) could directly oxidize TFI/PDFI to produce strong CL emission in acidic solution. The effects of experimental conditions were investigated. Under the optimal conditions, the effect of albumin on the TFI/PDFI-KMnO(4) system was investigated. It was found that the addition of albumin into the system could induce enhancement of CL signal, and the enhanced CL intensity is linearly related to the logarithm of concentration of albumin. Based on this study, a novel CL method has been developed for the determination of albumin with high sensitivity and good selectivity. The method was applied to the determination of albumin in human serum samples, and the results were in agreement with those obtained by the bromcresol green (BCG) method. The relative errors for the analytical results were from -5.8% to 4.2%. These new phenomena would further enable people to exploit more CL analytical application of the heterocyclic imidazole derivatives. © Springer Science+Business Media, LLC 2011

Imidazole and beta-carotene photoprotection against photodynamic therapy evaluated by synchrotron infrared microscopy

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Bosio, Gabriela N.; Parisi, Julieta; García Einschlag, Fernando S.; Mártire, Daniel O.

2018-04-01

In order to better understand the role of β-carotene and imidazole on the Photodynamic Therapy (PDT) mechanism, synchrotron infrared microscopy was used to detect the associated intracellular biochemical modifications following the visible light irradiation of HeLa cells incubated with these compounds as typical hydrophobic and hydrophilic singlet oxygen quenchers, respectively. For this purpose, PDT was performed employing the hydrophilic sensitizer 5,10,15,20-Tetrakis (1-methyl-4-pyridinio) porphyrin tetra (p-toluenesulfonate), TMPyP, and the hydrophobic sensitizer 5-(4-Methoxycarboxyphenyl)-10,15,20-triphenyl-21H,23H-porphyrin. The single cell IR spectra of PDT-treated, PDT plus quencher-treated and control HeLa cells were recorded at the SOLEIL Synchrotron Infrared SMIS beamline targeting specifically the cell nucleus. Principal Component Analysis (PCA) was used to assess the IR spectral changes. PCA revealed that there is a frequency shift of the protein Amide I vibrational band for the assays with the TMPyP sensitizer, indicating changes in the protein secondary structures of the PDT-treated cancer cells compared to the controls. In addition, the scores in those cells treated with both quenchers appear to be similar to the controls indicating a photoprotective effect. Comparative experiments carried out with SKMEL-28 and HaCat cells showed non- significant photoprotective effects of β-carotene and imidazole.

Red clump stars from the LAMOST data I: identification and distance

International Nuclear Information System (INIS)

Wan, Jun-Chen; Liu, Chao; Deng, Li-Cai; Yang, Ming; Wu, Yue; Cui, Wen-Yuan; Zhang, Yong; Hou, Yong-Hui

2015-01-01

We present a sample of about 120 000 red clump candidates selected from the LAMOST DR2 catalog based on the empirical distribution model in the effective temperature vs. surface gravity plane. Although, in general, red clump stars are considered as standard candles, they do not exactly stay in a narrow range of absolute magnitude, but may have a range of more than one magnitude depending on their initial mass. Consequently, conventional oversimplified distance estimations with the assumption of a fixed luminosity may lead to systematic bias related to the initial mass or age, which can potentially affect the study of the evolution of the Galaxy with red clump stars. We therefore employ an isochrone-based method to estimate the absolute magnitude of red clump stars from their observed surface gravities, effective temperatures and metallicities. We verify that the estimation removes the systematics well and provides initial mass/age estimates that are independent of distance with accuracy better than 10%. (paper)

Effect of phenols and carboxylic acids on photochromism of 1-alkyl-2-(arylazo)imidazoles

International Nuclear Information System (INIS)

Gayen, Pallab; Sinha, Chittaranjan

2012-01-01

Light irradiated trans-to-cis isomerization of 1-alkyl-2-(arylazo)imidazole in the presence of phenol, catechol, benzoic acid and salicylic acid (called co-factors) has been studied in this work. The rate of trans→cis photoisomerization is decreased in the presence of co-factor in the medium and is dependent on the concentration of active quotient about photochrome. The decrease in rate follows catechol>benzoic acid>phenol>salicylic acid. This trend is due to the effects of dissociation ability of –O–H/–COOH, intermolecular association of the molecules etc. The reverse change, cis-to-trans, is very slow in light irradiation and has been carried out by a thermal process in the dark. The quantum yield of isomerization follows the same sequence of effects of co-factors. - Highlights: ► Photoisomerisation of 1-alkyl-2-(arylazo)imidazoles, trans-to-cis, is described in this work. ► The process is sensitive to the environment of the photochrome and the solution. ► The rate of photoisomerization decreases as catechol>benzoic acid>phenol>salicylic acid. ► The reverse isomerization, cis-to-trans is very slow with light and has been carried out with heat. ► The activation energy is less than these values when carried out in fresh solution only.

Rapid estimation of earthquake magnitude from the arrival time of the peak high‐frequency amplitude

Science.gov (United States)

Noda, Shunta; Yamamoto, Shunroku; Ellsworth, William L.

2016-01-01

We propose a simple approach to measure earthquake magnitude M using the time difference (Top) between the body‐wave onset and the arrival time of the peak high‐frequency amplitude in an accelerogram. Measured in this manner, we find that Mw is proportional to 2logTop for earthquakes 5≤Mw≤7, which is the theoretical proportionality if Top is proportional to source dimension and stress drop is scale invariant. Using high‐frequency (>2  Hz) data, the root mean square (rms) residual between Mw and MTop(M estimated from Top) is approximately 0.5 magnitude units. The rms residuals of the high‐frequency data in passbands between 2 and 16 Hz are uniformly smaller than those obtained from the lower‐frequency data. Top depends weakly on epicentral distance, and this dependence can be ignored for distances earthquake produces a final magnitude estimate of M 9.0 at 120 s after the origin time. We conclude that Top of high‐frequency (>2  Hz) accelerograms has value in the context of earthquake early warning for extremely large events.

Does social distance modulate adults' egocentric biases when reasoning about false beliefs?

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Farrar, Benjamin G; Ostojić, Ljerka

2018-01-01

When given privileged information of an object's true location, adults often overestimate the likelihood that a protagonist holding a false belief will search in the correct location for that object. This type of egocentric bias is often labelled the 'curse of knowledge'. Interestingly, the magnitude of this bias may be modulated by the social distance between the perspective taker and target. However, this social distance effect has yet to be fully demonstrated when adults reason about false beliefs. Using a continuous false belief task, we investigated i) whether adults were biased by their own knowledge when reasoning about another's false belief, ii) whether the magnitude of this egocentric bias was modulated by social distance, and iii) whether this social distance effect extended to a heterospecific out-group, namely a dog. To test these hypotheses we conducted three experiments. In Experiment 1 (N = 283), we used an established continuous false belief task, in Experiment 2 (N = 281) we modified this task, and Experiment 3 (N = 744) was a direct replication of Experiment 2. Across these experiments, the curse of knowledge effect was reliably replicated when adults mentalised about an in-group protagonist, and replicated in two of the three studies (Experiments 1 and 3) when adults mentalised about out-group protagonists. In an internal-meta analysis, the curse of knowledge effect was present across all conditions, and there was no effect of social distance. Hence, overall these data are not consistent with the hypothesis that social distance modulates adults' egocentric biases when reasoning about false beliefs. The finding that egocentric biases of a similar magnitude were observed when adults mentalised about an in-group protagonist and a dog suggests that interpersonal dissimilarity is not in itself sufficient to reduce egocentric bias when reasoning about false beliefs.

The space between us: stereotype threat and distance in interracial contexts.

Science.gov (United States)

Goff, Phillip Atiba; Steele, Claude M; Davies, Paul G

2008-01-01

Four studies investigate the role that stereotype threat plays in producing racial distancing behavior in an anticipated conversation paradigm. It was hypothesized that the threat of appearing racist may have the ironic effect of causing Whites to distance themselves from Black conversation partners. In Study 1, participants distanced themselves more from Black partners under conditions of threat, and this distance correlated with the activation of a "White racist" stereotype. In Study 2, it was demonstrated that Whites' interracial distancing behavior was not predicted by explicit or implicit prejudice. Study 3 provides evidence that conceiving of interracial interactions as opportunities to learn may attenuate the negative consequences of threat for Whites. Study 4 found that Whites have conscious access to their experience of stereotype threat and that this awareness may mediate the relationship between threat and distance. These results are discussed within a broader discourse of racial distancing and the possibility that certain identity threats may be as important as prejudice in determining the outcomes of interracial interactions. Copyright 2008 APA, all rights reserved.

Synthetic polyspermine imidazole-4, 5-amide as an efficient and cytotoxicity-free gene delivery system

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Duan S

2012-07-01

Full Text Available Shi-Yue Duan, Xue-Mei Ge, Nan Lu, Fei Wu, Weien Yuan, Tuo JinSchool of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of ChinaAbstract: A chemically dynamic spermine-based polymer: polyspermine imidazole-4, 5-amide (PSIA, Mw > 7 kDa was designed, synthesized, and evaluated in terms of its ability to deliver nucleic acids. This polymer was made from an endogenous monomer professionally condensing genes in sperms, spermine, and a known safety drug metabolite, imidazole-4, 5-dicarboxylic acid, through a bis-amide bond conjugated with the imidazole ring. This polymer can condense pDNA at a W/W ratio above 10 to form polyplexes (100–200 nm in diameter, which is consistent with the observation by transmission electron microscopy (TEM, and the zeta potential was in the range of 10–20 mV. The pDNA packaged polymer was stable in phosphate buffer solution (PBS at pH 7.4 (simulated body fluid while the polyplexes were releasing pDNA into the solution at pH 5.8 (simulated endo-lysosomes due to the degradation of the bis-amide linkages in response to changes in pH values. PSIA-polyplexes were able to achieve efficient cellular uptake and luciferase gene silencing by co-transfection of pDNA and siRNA in COS-7 cells and HepG2 cells with negligible cytotoxicity. Biodistribution of Rhodamine B-labeled PSIA-polyplexes after being systemically injected in BALB/c nude-mice showed that the polyplexes circulated throughout the body, accumulated mainly in the kidney at 4 hours of sample administration, and moved to the liver and spleen after 24 hours. All the results suggested that PSIA offered a promising example to balance the transfection efficiency and toxicity of a synthetic carrier system for the delivery of therapeutic nucleic acids.Keywords: gene delivery, polyspermine, cytotoxicity, transfection efficiency, biodistribution

Elevated Serum Hepcidin Levels during an Intensified Training Period in Well-Trained Female Long-Distance Runners.

Science.gov (United States)

Ishibashi, Aya; Maeda, Naho; Sumi, Daichi; Goto, Kazushige

2017-03-14

Iron is essential for providing oxygen to working muscles during exercise, and iron deficiency leads to decreased exercise capacity during endurance events. However, the mechanism of iron deficiency among endurance athletes remains unclear. In this study, we compared iron status between two periods involving different training regimens. Sixteen female long-distance runners participated. Over a seven-month period, fasting blood samples were collected during their regular training period (LOW; middle of February) and during an intensified training period (INT; late of August) to determine blood hematological, iron, and inflammatory parameters. Three-day food diaries were also assessed. Body weight and lean body mass did not differ significantly between LOW and INT, while body fat and body fat percentage were significantly lower in INT ( p daily diet were significantly higher during INT than LOW ( p daily intake of iron.

Water swelling, brine soluble imidazole based zwitterionic polymers-synthesis and study of reversible UCST behaviour and gel-sol transitions

NARCIS (Netherlands)

Vasantha, Vivek Arjunan; Jana, Satyasankar; Parthiban, Anbanandam; Vancso, Julius G.

2014-01-01

New vinylbenzene substituted imidazole based zwitterionic polymers with unique characteristics like swelling in water and solubility in concentrated brine solution in which they exhibited a reversible upper critical solution temperature (UCST) and gel-sol transitions are reported herein. © 2014 The

Earthquake Magnitude and Shaking Intensity Dependent Fragility Functions for Rapid Risk Assessment of Buildings

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Marie-José Nollet

2018-01-01

Full Text Available An integrated web application, referred to as ER2 for rapid risk evaluator, is under development for a user-friendly seismic risk assessment by the non-expert public safety community. The assessment of likely negative consequences is based on pre-populated databases of seismic, building inventory and vulnerability parameters. To further accelerate the computation for near real-time analyses, implicit building fragility curves were developed as functions of the magnitude and the intensity of the seismic shaking defined with a single intensity measure, input spectral acceleration at 1.0 s implicitly considering the epicentral distance and local soil conditions. Damage probabilities were compared with those obtained with the standard fragility functions explicitly considering epicentral distances and local site classes in addition to the earthquake magnitudes and respective intensity of the seismic shaking. Different seismic scenarios were considered first for 53 building classes common in Eastern Canada, and then a reduced number of 24 combined building classes was proposed. Comparison of results indicate that the damage predictions with implicit fragility functions for short (M ≤ 5.5 and medium strong motion duration (5.5 < M ≤ 7.5 show low variation with distance and soil class, with average error of less than 3.6%.

1-[(1-Methyl-1H-imidazol-5-ylmethyl]-1H-indole-5-carbonitrile

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Josephus Jacobus de Jager

2012-12-01

Full Text Available In the title compound, C14H12N4, the dihedral angle between the indole ring system (r.m.s. deviation = 0.010 Å and the imidazole ring is 77.70 (6°. In the crystal, molecules are linked by C—H...N hydrogen bonds. One set of hydrogen bonds forms an undulating chain running parallel to the b-axis direction, while the other undulating chain is parallel to the c-axis direction. In combination, (100 sheets result.

Enhancement the Armor Shielding Properties of CF/epoxy Composite by Addition Nanoparticles of Magnetic Iron Oxide

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Fouda Hany

2017-01-01

Full Text Available In the present investigation, we prepared two types of CF composites. The first prepared composite sample was CF/epoxy resin composite and the second was CF/epoxy resin / with a different weight ratio of magnetic iron oxide. Magnetic iron oxide was prepared by co-precipitation method, with particle sizes measured in range 25:35 nm. The resistance to penetration of high kinetic energy projectile of the prepared composite sample was measured and It was found that addition of 5% nano-particles of magnetic iron oxide to composite material sample decrease the residual velocity of projectile penetrating it by 9%.i.e increasing resistance of the sample to penetration of high kinetic energy projectile.it was found that the Resistance to penetration of sheet of composite material sampleC4 of weight=40.32kg to projectile 7.62×39 mm AP at distance 15m equivalent to resistance of steel sheet of weight =54.6 kg at distance 200m.Resistance to penetration of sheet of composite material sampleC4 to projectile 7.62×39 mm AP at distance 10m equivalent to the resistance of high-quality steel sheet(steel4340 of weight=47.85 kg at distance 25m.

Bis(1H-imidazole-κN3bis(1-naphthaleneacetato-κ2O,O′cadmium(II

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Hong-Mian Wu

2008-05-01

Full Text Available In the mononuclear title compound, [Cd(C12H9O22(C3H4N22], the CdII centre has a distorted octahedral coordination geometry defined by four O atoms from two naphthaleneacetate ligands and two N atoms from two imidazole ligands. The molecules are linked by N—H...O hydrogen bonds, forming a layer network.

Calibrating the Type Ia Supernova Distance Scale Using Surface Brightness Fluctuations

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Potter, Cicely; Jensen, Joseph B.; Blakeslee, John; Milne, Peter; Garnavich, Peter M.; Brown, Peter

2018-06-01

We have observed 20 supernova host galaxies with HST WFC3/IR in the F110W filter, and prepared the data for Surface Brightness Fluctuation (SBF) distance measurements. The purpose of this study is to determine if there are any discrepancies between the SBF distance scale and the type-Ia SN distance scale, for which local calibrators are scarce. We have now measured SBF magnitudes to all early-type galaxies that have hosted SN Ia within 80 Mpc for which SBF measurements are possible. SBF is the only distance measurement technique with statistical uncertainties comparable to SN Ia that can be applied to galaxies out to 80 Mpc.

Thermal and mechanical stability of zeolitic imidazolate frameworks polymorphs

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Lila Bouëssel du Bourg

2014-12-01

Full Text Available Theoretical studies on the experimental feasibility of hypothetical Zeolitic Imidazolate Frameworks (ZIFs have focused so far on relative energy of various polymorphs by energy minimization at the quantum chemical level. We present here a systematic study of stability of 18 ZIFs as a function of temperature and pressure by molecular dynamics simulations. This approach allows us to better understand the limited stability of some experimental structures upon solvent or guest removal. We also find that many of the hypothetical ZIFs proposed in the literature are not stable at room temperature. Mechanical and thermal stability criteria thus need to be considered for the prediction of new MOF structures. Finally, we predict a variety of thermal expansion behavior for ZIFs as a function of framework topology, with some materials showing large negative volume thermal expansion.

The marine sponge Agelas citrina as a source of the new pyrrole–imidazole alkaloids citrinamines A–D and N-methylagelongine

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Christine Cychon

2015-10-01

Full Text Available The chemical investigation of the Caribbean sponge Agelas citrina revealed four new pyrrole–imidazole alkaloids (PIAs, the citrinamines A–D (1–4 and the bromopyrrole alkaloid N-methylagelongine (5. All citrinamines are dimers of hymenidin (6 which was also isolated from this sponge as the major metabolite. Citrinamines A (1 and B (2 are derivatives of the PIA dimer mauritiamine (7, whereas citrinamine C (3 is derived from the PIA dimer nagelamide B (8. Citrinamine D (4 shows an uncommon linkage between the imidazole rings of both monomeric units as it is only observed in the benzocyclobutane ring moiety of benzosceptrins A–C (9–11. Compound 5 is the N-methyl derivative of agelongine (12 which consist of a pyridinium ring and an ester linkage instead of the aminoimidazole moiety and the common amide bond in PIAs.

Iron and stony-iron meteorites

DEFF Research Database (Denmark)

Ruzicka, Alex M.; Haack, Henning; Chabot, Nancy L.

2017-01-01

By far most of the melted and differentiated planetesimals that have been sampled as meteorites are metal-rich iron meteorites or stony iron meteorites. The parent asteroids of these meteorites accreted early and differentiated shortly after the solar system formed, producing some of the oldest...... and interpretations for iron and stony iron meteorites (Plate 13.1). Such meteorites provide important constraints on the nature of metal-silicate separation and mixing in planetesimals undergoing partial to complete differentiation. They include iron meteorites that formed by the solidification of cores...... (fractionally crystallized irons), irons in which partly molten metal and silicates of diverse types were mixed together (silicate-bearing irons), stony irons in which partly molten metal and olivine from cores and mantles were mixed together (pallasites), and stony irons in which partly molten metal...

Synthesis and characterization of new N-heterocyclic carbene ligands: 1,3-Bis(acetamide)imidazol-3-ium bromide and 3-(acetamide)-1-(3-aminopropyl)-1H-imidazol-3-ium bromide

Science.gov (United States)

Turkyilmaz, Murat; Uluçam, Gühergül; Aktaş, Şaban; Okan, S. Erol

2017-05-01

Two new pincer type N-heterocyclic carbene ligands were synthesized. The compounds were characterized by FTIR, NMR (1H, 13C) GC-MS and elemental analyses. They were also both modelled by DFT calculations as the crystal structure of 1,3-bis(acetamide)imidazol-3-ium bromide was determined by XRD which is an orthorhombic system with space group P21212. The structural analyses in gas phase were realized by comparing the experimental NMR and IR spectra with those of the theoretical calculations. In vitro biological activities of the molecules were determined and found that one of them exhibits significant cytotoxic activity.

Transformation of vivianite by anaerobic nitrate-reducing iron-oxidizing bacteria.

Science.gov (United States)

Miot, J; Benzerara, K; Morin, G; Bernard, S; Beyssac, O; Larquet, E; Kappler, A; Guyot, F

2009-06-01

In phosphate-rich environments, vivianite (Fe(II)(3)(PO(4))(2), 8H(2)O) is an important sink for dissolved Fe(II) and is considered as a very stable mineral due to its low solubility at neutral pH. In the present study, we report the mineralogical transformation of vivianite in cultures of the nitrate-reducing iron-oxidizing bacterial strain BoFeN1 in the presence of dissolved Fe(II). Vivianite was first transformed into a greenish phase consisting mostly of an amorphous mixed valence Fe-phosphate. This precipitate became progressively orange and the final product of iron oxidation consisted of an amorphous Fe(III)-phosphate. The sub-micrometer analysis by scanning transmission X-ray microscopy of the iron redox state in samples collected at different stages of the culture indicated that iron was progressively oxidized at the contact of the bacteria and at a distance from the cells in extracellular minerals. Iron oxidation in the extracellular minerals was delayed by a few days compared with cell-associated Fe-minerals. This led to strong differences of Fe redox in between these two types of minerals and finally to local heterogeneities of redox within the sample. In the absence of dissolved Fe(II), vivianite was not significantly transformed by BoFeN1. Whereas Fe(II) oxidation at the cell contact is most probably directly catalyzed by the bacteria, vivianite transformation at a distance from the cells might result from oxidation by nitrite. In addition, processes leading to the export of Fe(III) from bacterial oxidation sites to extracellular minerals are discussed including some involving colloids observed by cryo-transmission electron microscopy in the culture medium.

Heliocentric distance dependence of the interplanetary magnetic field

International Nuclear Information System (INIS)

Behannon, K.W.

1978-01-01

Recent and ongoing planetary missions have provided and are continuing to provide extensive observations of the variations of the interplanetary magnetic field (IMF) both in time and with heliocentric distance from the sun. Large time variations in both the IMF and its fluctuations are observed. These are produced predominantly by dynamical processes in the interplanetary medium associated with stream interactions. Magnetic field variations near the sun are propagated to greater heliocentric distances, a process also contributing to the observed variability of the IMF. Temporal variations on a time scale comparable to or less than the corotation period complicate attempts to deduce radial gradients of the field and its fluctuations from the various observations. However, recent measurements inward to 0.46 AU and outward to 5 AU suggest that the radial component of the field on average decreases approximately as r -2 , as was predicted by Parker, while the azimuthal component decreases more rapidly than the r -1 dependence predicted by simple theory. Three sets of observations are consistent with r/sup -1.3/ dependence for vertical-barB/sub phi/vertical-bar. The temporal variability of solar wind speed is most likely the predominant contributor to this latter observational result. The long-term average azimuthal component radial gradient is probably consistent with the Parker r -1 dependence when solar wind speed variations are taken into account. The observations of the normal component magnitude vertical-barB/sub theta/vertical-bar are roughly consistent with a heliocentric distance dependence of r/sup -1.4/. The observed radial distance dependence of the total magnitude of the IMF is well described by the Parker formulation. There is observational evidence that amplitudes of fluctuations of the vector field with periods less than 1 day vary with heliocentric distance as approximately r/sup -3/2/, in agreement with theoretical models by Whang and Hollweg

Synthesis of pyrido[1,2-a]benzimidazoles and other fused imidazole derivatives with a bridgehead nitrogen atom

Science.gov (United States)

Begunov, Roman S.; Ryzvanovich, Galina A.

2013-01-01

Main methods for the synthesis of fused imidazole derivatives with a bridgehead nitrogen atom are systematically considered and summarized. The reaction mechanisms that underlie the methods for the synthesis of pyrido[1,2-a]benzimidazoles and related compounds are described. Biological properties and mechanisms of the biological activity of fused azaheterocycles are discussed. The bibliography includes 152 references.

Nitrogen Abundances and the Distance Moduli of the Pleiades and Hyades

OpenAIRE

Miller, Blake; King, Jeremy R.; Chen, Yu; Boesgaard, Ann M.

2013-01-01

Recent reanalyses of HIPPARCOS parallax data confirm a previously noted discrepancy with the Pleiades distance modulus estimated from main-sequence fitting in the color-magnitude diagram. One proposed explanation of this distance modulus discrepancy is a Pleiades He abundance that is significantly larger than the Hyades value. We suggest that, based on our theoretical and observational understanding of Galactic chemical evolution, nitrogen abundances may serve as a proxy for helium abundances...

Effect of phenols and carboxylic acids on photochromism of 1-alkyl-2-(arylazo)imidazoles

Energy Technology Data Exchange (ETDEWEB)

Gayen, Pallab [Inorganic Chemistry Section, Department of Chemistry, Jadavpur University, Kolkata 700032 (India); Sinha, Chittaranjan, E-mail: c_r_sinha@yahoo.com [Inorganic Chemistry Section, Department of Chemistry, Jadavpur University, Kolkata 700032 (India)

2012-09-15

Light irradiated trans-to-cis isomerization of 1-alkyl-2-(arylazo)imidazole in the presence of phenol, catechol, benzoic acid and salicylic acid (called co-factors) has been studied in this work. The rate of trans{yields}cis photoisomerization is decreased in the presence of co-factor in the medium and is dependent on the concentration of active quotient about photochrome. The decrease in rate follows catechol>benzoic acid>phenol>salicylic acid. This trend is due to the effects of dissociation ability of -O-H/-COOH, intermolecular association of the molecules etc. The reverse change, cis-to-trans, is very slow in light irradiation and has been carried out by a thermal process in the dark. The quantum yield of isomerization follows the same sequence of effects of co-factors. - Highlights: Black-Right-Pointing-Pointer Photoisomerisation of 1-alkyl-2-(arylazo)imidazoles, trans-to-cis, is described in this work. Black-Right-Pointing-Pointer The process is sensitive to the environment of the photochrome and the solution. Black-Right-Pointing-Pointer The rate of photoisomerization decreases as catechol>benzoic acid>phenol>salicylic acid. Black-Right-Pointing-Pointer The reverse isomerization, cis-to-trans is very slow with light and has been carried out with heat. Black-Right-Pointing-Pointer The activation energy is less than these values when carried out in fresh solution only.

Tests of the Tully-Fisher relation. 1: Scatter in infrared magnitude versus 21 cm width

Science.gov (United States)

Bernstein, Gary M.; Guhathakurta, Puragra; Raychaudhury, Somak; Giovanelli, Riccardo; Haynes, Martha P.; Herter, Terry; Vogt, Nicole P.

1994-01-01

We examine the precision of the Tully-Fisher relation (TFR) using a sample of galaxies in the Coma region of the sky, and find that it is good to 5% or better in measuring relative distances. Total magnitudes and disk axis ratios are derived from H and I band surface photometry, and Arecibo 21 cm profiles define the rotation speeds of the galaxies. Using 25 galaxies for which the disk inclination and 21 cm width are well defined, we find an rms deviation of 0.10 mag from a linear TFR with dI/d(log W(sub c)) = -5.6. Each galaxy is assumed to be at a distance proportional to its redshift, and an extinction correction of 1.4(1-b/a) mag is applied to the total I magnitude. The measured scatter is less than 0.15 mag using milder extinction laws from the literature. The I band TFR scatter is consistent with measurement error, and the 95% CL limits on the intrinsic scatter are 0-0.10 mag. The rms scatter using H band magnitudes is 0.20 mag (N = 17). The low width galaxies have scatter in H significantly in excess of known measurement error, but the higher width half of the galaxies have scatter consistent with measurement error. The H band TFR slope may be as steep as the I band slope. As the first applications of this tight correlation, we note the following: (1) the data for the particular spirals commonly used to define the TFR distance to the Coma cluster are inconsistent with being at a common distance and are in fact in free Hubble expansion, with an upper limit of 300 km/s on the rms peculiar line-of-sight velocity of these gas-rich spirals; and (2) the gravitational potential in the disks of these galaxies has typical ellipticity less than 5%. The published data for three nearby spiral galaxies with Cepheid distance determinations are inconsistent with our Coma TFR, suggesting that these local calibrators are either ill-measured or peculiar relative to the Coma Supercluster spirals, or that the TFR has a varying form in different locales.

Inter-granular current in iron-oxypnictide superconductors

International Nuclear Information System (INIS)

Tamegai, T.; Tsuchiya, Y.; Nakajima, Y.; Kamihara, Y.; Hosono, H.

2010-01-01

Inter- and intragranular currents, J c inter and J c intra , in LaFePO 0.94 F 0.06 polycrystalline sample are evaluated by measuring the remanent-state field profile using magneto-optical imaging method. Obtained images show the absence of magnetic field modulation associated with the weak-link nature of grain boundaries, indicating that J c inter and J c intra are comparable in magnitude in contrast to other iron-arsenide superconductors. J c inter is estimated to be 2 x 10 4 A/cm 2 in the limit of T = 0 K, which is larger than the values in other iron-arsenide superconductors. Implication of these J c behavior is discussed in relation with possible pairing symmetries.

Resumming Long-Distance Contributions to the QCD Pressure

CERN Document Server

Kajantie, Keijo; Rummukainen, K; Schröder, Y

2001-01-01

The strict coupling constant expansion for the free energy of hot QCD plasma shows bad convergence at all reasonable temperatures, and does not agree well with its 4d lattice determination. This has recently lead to various refined resummations, whereby the agreement with the lattice result should improve, at the cost of a loss of a formal agreement with the coupling constant expansion and particularly with its large infrared sensitive ``long-distance'' contributions. We show here how to resum the dominant long-distance effects by using a 3d effective field theory, and determine their magnitude by simple lattice Monte Carlo simulations.

Synthesis and antimicrobial properties of 3-aryl-1-(1,1'-biphenyl-4-yl)-2-(1H-imidazol-1-yl)propanes as 'carba-analogues' of the N-arylmethyl-N-[(1,1'-biphenyl)-4-ylmethyl])-1H-imidazol-1-amines, a new class of antifungal agents.

Science.gov (United States)

Castellano, Sabrina; Stefancich, Giorgio; Chillotti, Annalisa; Poni, Graziella

2003-08-01

A new series of 3-phenyl-1-(1,1'-biphenyl-4-yl)-2-(1H-imidazol-1-yl)propane derivatives 2a-l (related to the antifungal bifonazole) was synthesized and tested for antimicrobial activity. A number of substituents on the phenyl ring were chosen to compare the relative biological properties with those of corresponding aza-analogues, previously described by us. The in vitro antifungal activities of the newly synthesized azoles were tested against several pathogenic fungi responsible for human disease. Test pathogens included representatives of yeasts (Candida albicans, Candida parapsilosis, Criptococcus neoformans), dermathophytes (Tricophyton verrucosum, Tricophyton rubrum, Microsporum gypseum) and moulds (Aspergillus fumigatus). Bifonazole and miconazole were used as reference drugs. Title compounds were prepared by alkylation of 1-biphenyl-4-yl-2-imidazol-1-yl-ethanone with the proper arylmethyl halide and subsequent reduction of corresponding ketones applying the Huang-Minlon modification of the Wolff-Kishner reaction.

Magnitude conversion to unified moment magnitude using orthogonal regression relation

Science.gov (United States)

Das, Ranjit; Wason, H. R.; Sharma, M. L.

2012-05-01

Homogenization of earthquake catalog being a pre-requisite for seismic hazard assessment requires region based magnitude conversion relationships. Linear Standard Regression (SR) relations fail when both the magnitudes have measurement errors. To accomplish homogenization, techniques like Orthogonal Standard Regression (OSR) are thus used. In this paper a technique is proposed for using such OSR for preparation of homogenized earthquake catalog in moment magnitude Mw. For derivation of orthogonal regression relation between mb and Mw, a data set consisting of 171 events with observed body wave magnitudes (mb,obs) and moment magnitude (Mw,obs) values has been taken from ISC and GCMT databases for Northeast India and adjoining region for the period 1978-2006. Firstly, an OSR relation given below has been developed using mb,obs and Mw,obs values corresponding to 150 events from this data set. M=1.3(±0.004)m-1.4(±0.130), where mb,proxy are body wave magnitude values of the points on the OSR line given by the orthogonality criterion, for observed (mb,obs, Mw,obs) points. A linear relation is then developed between these 150 mb,obs values and corresponding mb,proxy values given by the OSR line using orthogonality criterion. The relation obtained is m=0.878(±0.03)m+0.653(±0.15). The accuracy of the above procedure has been checked with the rest of the data i.e., 21 events values. The improvement in the correlation coefficient value between mb,obs and Mw estimated using the proposed procedure compared to the correlation coefficient value between mb,obs and Mw,obs shows the advantage of OSR relationship for homogenization. The OSR procedure developed in this study can be used to homogenize any catalog containing various magnitudes (e.g., ML, mb, MS) with measurement errors, by their conversion to unified moment magnitude Mw. The proposed procedure also remains valid in case the magnitudes have measurement errors of different orders, i.e. the error variance ratio is

Friction welding of ductile cast iron using interlayers

International Nuclear Information System (INIS)

Winiczenko, Radoslaw; Kaczorowski, Mieczyslaw

2012-01-01

Highlights: → The results of the study of the friction welding of ductile cast iron using interlayers are presented. → The results of the analysis shows that the joint has the tensile strength compared to that of basic material. → In case of ductile cast iron, it is possible to reach the tensile strength equals even 700 MPa. → The process of friction welding was accompanied with diffusion of Cr, Ni and C atoms across the interface. -- Abstract: In this paper, ductile cast iron-austenitic stainless steel, ductile cast iron-pure Armco iron and ductile cast iron-low carbon steel interlayers were welded, using the friction welding method. The tensile strength of the joints was determined, using a conventional tensile test machine. Moreover, the hardness across the interface of materials was measured on metallographic specimens. The fracture surface and microstructure of the joints was examined using either light stereoscope microscopy as well as electron microscopy. In this case, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were applied. The results of the analysis shows that the joint has the tensile strength compared to that of basic material. In case of ductile cast iron, it is possible to reach the tensile strength equals even 700 MPa. It was concluded that the process of friction welding was accompanied with diffusion of Cr, Ni and C atoms across the ductile cast iron-stainless steel interface. This leads to increase in carbon concentration in stainless steel where chromium carbides were formed, the size and distribution of which was dependent on the distance from the interface.

Siderophores as iron storage compounds in the yeasts Rhodotorula minuta and Ustilago sphaerogena detected by in vivo Moessbauer spectroscopy

International Nuclear Information System (INIS)

Matzanke, B.F.; Winkelmann, G.; Bill, E.; Trautwein, A.X.

1990-01-01

In the yeasts Rhodotorula minuta and Ustilago sphaerogena siderophores represent the main intracellular iron pool. We suggest a ferritin substituting function of these siderophores in addition to their role as iron transport agents. In Rhodotorula transport and storage siderophore is the same compound whereas in Ustilago the iron-storage siderophore is ferrichrome. Besides siderophores, merely two iron metabolites can be observed. Other iron-requiring compounds are at least one order of magnitude less abundant in these yeasts. The ferrous metabolite has been detected in many other microbial systems and seems to be of general occurence and importance. (orig.)

Local magnitude, duration magnitude and seismic moment of Dahshour 1992 earthquakes

Directory of Open Access Journals (Sweden)

M. F. Abdelwahed

2000-06-01

Full Text Available Local magnitudes ML have been calculated for 56 earthquakes of the Dahshour 1992 sequence using simulated records of the KEG broadband station and the estimated calibration function of the Dahshour area. These were compared with their corresponding values of duration magnitudes obtained from the analog short period seismograms of the HLW station. The local magnitudes M L and the duration magnitudes M D for this region imply a linear relation as follows: M L = 1.2988 (± 0.04 M D – 0.9032 (± 0.14. Seismic moment has also been estimated for these events using simple measurements from the time domain records. These measurements based on the simulated Wood Anderson seismograms are used for the local magnitude (ML estimation. The derived relationship between seismic moment (M 0 and magnitude (M L is: log (M 0 = 0.954 (± 0.019 M L + 17.258 (± 0.075.

Cloud Point Extraction and Determination of Silver Ion in Real Sample using Bis((1H-benzo[d ]imidazol-2ylmethylsulfane

Directory of Open Access Journals (Sweden)

Farshid Ahmadi

2011-01-01

Full Text Available Bis((1H-benzo[d]imidazol-2ylmethylsulfane (BHIS was used as a complexing agent in cloud point extraction for the first time and applied for selective pre-concentration of trace amounts of silver. The method is based on the extraction of silver at pH 8.0 by using non-ionic surfactant T-X114 and bis((1H-benzo[d]imidazol-2ylmethylsulfane as a chelating agent. The adopted concentrations for BHIS, Triton X-114 and HNO3, bath temperature, centrifuge rate and time were optimized. Detection limits (3SDb/m of 1.7 along with enrichment factor of 39 for silver ion was achieved. The high efficiency of cloud point extraction to carry out the determination of analytes in complex matrices was demonstrated. The proposed method was successfully applied to the ultra-trace determination of silver in real samples.

Local magnitude, duration magnitude and seismic moment of Dahshour 1992 earthquakes

OpenAIRE

M. F. Abdelwahed; E. M. Abdelrahman; H. M. Hussein; M. M. Dessokey

2000-01-01

Local magnitudes ML have been calculated for 56 earthquakes of the Dahshour 1992 sequence using simulated records of the KEG broadband station and the estimated calibration function of the Dahshour area. These were compared with their corresponding values of duration magnitudes obtained from the analog short period seismograms of the HLW station. The local magnitudes M L and the duration magnitudes M D for this region imply a linear relation as follows: M L = 1.2988 (± 0.04) M D – 0.9032 (± 0...

Enhanced transport of zerovalent iron nanoparticles in saturated porous media by guar gum

International Nuclear Information System (INIS)

Tiraferri, Alberto; Sethi, Rajandrea

2009-01-01

In order to ensure adequate mobility of zerovalent iron nanoparticles in natural aquifers, the use of a stabilizing agent is necessary. Polymers adsorbed on the nanoparticle surface will give rise to electrosteric stabilization and will decrease attachment to the surface soil grains. Water saturated sand-packed columns were used in this study to investigate the transport of iron nanoparticle suspensions, bare or modified with the green polymer guar gum. The suspensions were prepared at 154 mg/L particle concentration and 0.5 g/L polymer concentration. Transport experiments were conducted by varying the ionic strength, ionic composition, and approach velocity of the fluid. Nanoparticle deposition rates, attachment efficiencies, and travel distances were subsequently calculated based on the classical particle filtration theory. It was found that bare iron nanoparticles are basically immobile in sandy porous media. In contrast, guar gum is able to ensure significant nanoparticle transport at the tested conditions, regardless of the chemistry of the solution. Attachment efficiency values for guar gum-coated nanoparticles under the various conditions tested were smaller than 0.066. Although the calculated travel distances may not prove satisfactory for field application, the investigation attested the promising role of guar gum to ensure mobility of iron nanoparticles in the subsurface environment.

Kinetics of chromium (VI) reduction by ferrous iron

International Nuclear Information System (INIS)

Batchelor, B.; Schlautman, M.; Hwang, I.; Wang, R.

1998-09-01

Chromium is a primary inorganic contaminant of concern at the Pantex Plant. Chromium concentrations have been found to be two orders of magnitude higher than the drinking water standards, particularly in certain wells in the perched aquifer below Zone 12. In situ reduction of a mobile form of chromium, Cr(VI) to an immobile form, Cr(III), was examined as a viable option to active soil restoration. Successfully immobilizing chromium in the vadose zone as Cr(III) will reduce the amount of chromium that reaches the groundwater table. The results from the solution experiments indicated that chromium was rapidly and stoichiometrically reduced by Fe(II) in solution. Also, the slurry experiments showed that the aquifer solids removed Fe(II) from solution, but a portion of the iron removed remained available for reaction with Cr(VI), but at a slower rate. A model to predict different amounts of iron pseudo-components was developed, which allowed prediction of iron amounts required to reduce chromium under in situ conditions

The representation of object distance: evidence from neuroimaging and neuropsychology

Directory of Open Access Journals (Sweden)

Marian Berryhill

2009-11-01

Full Text Available Perceived distance in two-dimensional images relies on monocular distance cues. Here, we examined the representation of perceived object distance using a continuous carry-over adaptation design for fMRI. The task was to look at photographs of objects and make a judgment as to whether or not the item belonged in the kitchen. Importantly, this task was orthogonal to the variable of interest: the object’s perceived distance from the viewer. In Experiment 1, whole brain group analyses identified bilateral clusters in the superior occipital gyrus (approximately area V3/V3A that showed parametric adaptation to relative changes in perceived distance. In Experiment 2, retinotopic analyses confirmed that area V3A/B reflected the greatest magnitude of response to monocular changes in perceived distance. In Experiment 3, we report that the functional activations overlap with the occipito-parietal lesions in a patient with impaired distance perception, showing that the same regions monitor implied (two-dimensional and actual (three-dimensional distance. These data suggest that distance information is automatically processed even when it is task-irrelevant and that this process relies on superior occipital areas in and around area V3A.

Pharmacological ascorbate and ionizing radiation (IR increase labile iron in pancreatic cancer

Directory of Open Access Journals (Sweden)

Justin C. Moser

2014-01-01

Full Text Available Labile iron, i.e. iron that is weakly bound and is relatively unrestricted in its redox activity, has been implicated in both the pathogenesis as well as treatment of cancer. Two cancer treatments where labile iron may contribute to their mechanism of action are pharmacological ascorbate and ionizing radiation (IR. Pharmacological ascorbate has been shown to have tumor-specific toxic effects due to the formation of hydrogen peroxide. By catalyzing the oxidation of ascorbate, labile iron can enhance the rate of formation of hydrogen peroxide; labile iron can also react with hydrogen peroxide. Here we have investigated the magnitude of the labile iron pool in tumor and normal tissue. We also examined the ability of pharmacological ascorbate and IR to change the size of the labile iron pool. Although a significant amount of labile iron was seen in tumors (MIA PaCa-2 cells in athymic nude mice, higher levels were seen in murine tissues that were not susceptible to pharmacological ascorbate. Pharmacological ascorbate and irradiation were shown to increase the labile iron in tumor homogenates from this murine model of pancreatic cancer. As both IR and pharmacological ascorbate may rely on labile iron for their effects on tumor tissues, our data suggest that pharmacological ascorbate could be used as a radio-sensitizing agent for some radio-resistant tumors.

Determination of imidazole derivatives by micellar electrokinetic chromatography combined with solid-phase microextraction using activated carbon-polymer monolith as adsorbent.

Science.gov (United States)

Shih, Yung-Han; Lirio, Stephen; Li, Chih-Keng; Liu, Wan-Ling; Huang, Hsi-Ya

2016-01-08

In this study, an effective method for the separation of imidazole derivatives 2-methylimidazole (2-MEI), 4- methylimidazole (4-MEI) and 2-acetyl-4-tetrahydroxybutylimidazole (THI) in caramel colors using cation-selective exhaustive injection and sweeping micellar electrokinetic chromatography (CSEI-sweeping-MEKC) was developed. The limits of detection (LOD) and quantitation (LOQ) for the CSEI-sweeping-MEKC method were in the range of 4.3-80μgL(-1) and 14-270μgL(-1), respectively. Meanwhile, a rapid fabrication activated carbon-polymer (AC-polymer) monolithic column as adsorbent for solid-phase microextraction (SPME) of imidazole colors was developed. Under the optimized SPME condition, the extraction recoveries for intra-day, inter-day and column-to-column were in the range of 84.5-95.1% (<6.3% RSDs), 85.6-96.1% (<4.9% RSDs), and 81.3-96.1% (<7.1% RSDs), respectively. The LODs and LOQs of AC-polymer monolithic column combined with CSEI-sweeping-MEKC method were in the range of 33.4-60.4μgL(-1) and 111.7-201.2μgL(-1), respectively. The use of AC-polymer as SPME adsorbent demonstrated the reduction of matrix effect in food samples such as soft drink and alcoholic beverage thereby benefiting successful determination of trace-level caramel colors residues using CSEI-sweeping-MEKC method. The developed AC-polymer monolithic column can be reused for more than 30 times without any significant loss in the extraction recovery for imidazole derivatives. Copyright © 2015 Elsevier B.V. All rights reserved.

Faradaic impedance titration and control of electron transfer of 1-(12-mercaptododecyl)imidazole monolayer on a gold electrode

International Nuclear Information System (INIS)

Hwang, Seongpil; Lee, Bang Sook; Chi, Young Shik; Kwak, Juhyoun; Choi, Insung S.; Lee, Sang-gi

2008-01-01

In this work, we studied interfacial proton transfer of the self-assembled monolayer (SAM) of 1-(12-mercaptododecyl)imidazole on a gold electrode by faradaic impedance titration method with Fe(CN) 6 3- as an anionic redox probe molecule. The surface pK 1/2 was found to be 7.3, which was nearly the same as that of 1-alkylimidazole in solution. We also investigated the electrochemical properties of the SAM-modified electrode by cyclic voltammetry. Cyclic voltammetry was performed (1) in the solution containing Fe(CN) 6 3- with repeated alternation of pH values to investigate the electrostatic interaction of the protonated or deprotonated imidazole with Fe(CN) 6 3- and (2) in the acidic or basic electrolyte containing Ru(NH 3 ) 6 3+ as a cationic redox probe to verify the effect of the polarity of a redox probe. We observed the reversible adsorption/desorption of Fe(CN) 6 3- and concluded that the adsorbed Fe(CN) 6 3- catalyzed the electron transfer of both Fe(CN) 6 3- itself and cationic Ru(NH 3 ) 6 3+

Physical models of corrosion of iron and nickel in liquid sodium

International Nuclear Information System (INIS)

Skyrme, G.

1975-11-01

The possible physical models for the corrosion of iron and nickel in liquid sodium loops are considered. The models are assessed in the light of available experimental evidence, in particular the magnitude of the corrosion rate and the velocity, downstream, temperature and oxygen effects. Currently recommended solubility values are used throughout. It is shown that the simple model based on these recommended values, which assumes that the dissolved metals are in equilibrium throughout the loop, overestimates the corrosion rate by three orders of magnitude. (author)

Testing the Quick Seismic Event Locator and Magnitude Calculator (SSL_Calc) by Marsite Project Data Base

Science.gov (United States)

Tunc, Suleyman; Tunc, Berna; Caka, Deniz; Baris, Serif

2016-04-01

Locating and calculating size of the seismic events is quickly one of the most important and challenging issue in especially real time seismology. In this study, we developed a Matlab application to locate seismic events and calculate their magnitudes (Local Magnitude and empirical Moment Magnitude) using single station called SSL_Calc. This newly developed sSoftware has been tested on the all stations of the Marsite project "New Directions in Seismic Hazard Assessment through Focused Earth Observation in the Marmara Supersite-MARsite". SSL_Calc algorithm is suitable both for velocity and acceleration sensors. Data has to be in GCF (Güralp Compressed Format). Online or offline data can be selected in SCREAM software (belongs to Guralp Systems Limited) and transferred to SSL_Calc. To locate event P and S wave picks have to be marked by using SSL_Calc window manually. During magnitude calculation, instrument correction has been removed and converted to real displacement in millimeter. Then the displacement data is converted to Wood Anderson Seismometer output by using; Z=[0;0]; P=[-6.28+4.71j; -6.28-4.71j]; A0=[2080] parameters. For Local Magnitude calculation,; maximum displacement amplitude (A) and distance (dist) are used in formula (1) for distances up to 200km and formula (2) for more than 200km. ML=log10(A)-(-1.118-0.0647*dist+0.00071*dist2-3.39E-6*dist3+5.71e-9*dist4) (1) ML=log10(A)+(2.1173+0.0082*dist-0.0000059628*dist2) (2) Following Local Magnitude calculation, the programcode calculates two empiric Moment Magnitudes using formulas (3) Akkar et al. (2010) and (4) Ulusay et al. (2004). Mw=0.953* ML+0.422 (3) Mw=0.7768* ML+1.5921 (4) SSL_Calc is a software that is easy to implement and user friendly and offers practical solution to individual users to location of event and ML, Mw calculation.

Tuning the crystal morphology and size of zeolitic imidazolate framework-8 in aqueous solution by surfactants

KAUST Repository

Pan, Yichang

2011-01-01

Herein we report a facile synthesis method using surfactant cetyltrimethylammonium bromide (CTAB) as a capping agent for controlling the crystal size and morphology of zeolitic imidazolate framework-8 (ZIF-8) crystals in aqueous systems. The particle sizes can be precisely adjusted from ca. 100 nm to 4 μm, and the morphology can be changed from truncated cubic to rhombic dodecahedron. This journal is © The Royal Society of Chemistry.

Chemical structure, network topology, and porosity effects on the mechanical properties of Zeolitic Imidazolate Frameworks

OpenAIRE

Tan, J. C.; Bennett, T. D.; Cheetham, A. K.

2010-01-01

The mechanical properties of seven zeolitic imidazolate frameworks (ZIFs) based on five unique network topologies have been systematically characterized by single-crystal nanoindentation studies. We demonstrate that the elastic properties of ZIF crystal structures are strongly correlated to the framework density and the underlying porosity. For the systems considered here, the elastic modulus was found to range from 3 to 10 GPa, whereas the hardness property lies between 300 MPa and 1.1 GPa. ...

Tioconazole, a new imidazole-antifungal agent for the treatment of dermatomycoses. Antifungal and pharmacologic properties.

Science.gov (United States)

Marriott, M S; Baird, J R; Brammer, K W; Faulkner, J K; Halliwell, G; Jevons, S; Tarbit, M H

1983-01-01

Tioconazole is a new imidazole antifungal agent with broad-spectrum activity. Its in vitro activity against common dermal pathogens is generally better than miconazole by a factor of 2-8. This activity is paralleled by good topical efficacy in a guinea pig dermatomycosis model. Pharmacokinetic studies in animals have demonstrated minimal systemic exposure following dermal application. Acute general pharmacology studies have shown that the compound is well tolerated in animals and unlikely to produce side-effects in man.

On the Real Magnitude of Psychological Sex Differences

Directory of Open Access Journals (Sweden)

Marco Del Giudice

2009-04-01

Full Text Available A comprehensive evolutionary theory of sex differences will benefit from an accurate assessment of their magnitude across different psychological domains. This article shows that mainstream research has severely underestimated the magnitude of psychological sex differences; the reason lies in the common practice of measuring multidimensional differences one dimension at a time, without integrating them into a proper multivariate effect size (ES. Employing the Mahalanobis distance D (the multivariate generalization of Cohen's d results in more accurate, and predictably larger, estimates of overall sex differences in multidimensional constructs. Two real-world examples are presented: (1 In a published dataset on Big Five personality traits, sex differences on individual scales averaged d = .27, a typical ES conventionally regarded as “small.” However, the overall difference was D = .84 (disattenuated D = .98, implying considerable statistical separation between male and female distributions. (2 In a recent meta-analytic summary of sex differences in aggression, the individual ESs averaged d = .34. However, the overall difference was estimated at D = .75 – .80 (disattenuated D = .89–1.01. In many psychological domains, sex differences may be substantially larger than previously acknowledged.

Siderophores as iron storage compounds in the yeasts Rhodotorula minuta and Ustilago sphaerogena detected by in vivo Mössbauer spectroscopy

Science.gov (United States)

Matzanke, B. F.; Bill, E.; Trautwein, A. X.; Winkelmann, G.

1990-07-01

In the yeasts Rhodotorula minuta and Ustilago sphaerogena siderophores represent the main intracellular iron pool. We suggest a ferritin substituting function of these siderophores in addition to their role as iron transport agents. In Rhodotorula transport and storage siderophore is the same compound whereas in Ustilago the iron-storage siderophore is ferrichrome. Besides siderophores, merely two iron metabolites can be observed. Other iron-requiring compounds are at least one order of magnitude less abundant in these yeasts. The ferrous metabolite has been detected in many other microbial systems and seems to be of general occurence and importance.

Local magnitude scale for Valle Medio del Magdalena region, Colombia

Science.gov (United States)

Londoño, John Makario; Romero, Jaime A.

2017-12-01

A local Magnitude (ML) scale for Valle Medio del Magdalena (VMM) region was defined by using 514 high quality earthquakes located at VMM area and inversion of 2797 amplitude values of horizontal components of 17 stations seismic broad band stations, simulated in a Wood-Anderson seismograph. The derived local magnitude scale for VMM region was: ML =log(A) + 1.3744 ∗ log(r) + 0.0014776 ∗ r - 2.397 + S Where A is the zero-to-peak amplitude in nm in horizontal components, r is the hypocentral distance in km, and S is the station correction. Higher values of ML were obtained for VMM region compared with those obtained with the current formula used for ML determination, and with California formula. With this new scale ML values are adjusted to local conditions beneath VMM region leading to more realistic ML values. Moreover, with this new ML scale the seismicity caused by tectonic or fracking activity at VMM region can be monitored more accurately.

Thermal migration of iron implanted in aluminium at high doses

International Nuclear Information System (INIS)

Asundi, V.K.; Joshi, M.C.; Deb, S.K.; Soud, D.K.; Kulkarni, V.N.; Sundararaman, M.

1978-01-01

The anneal behaviour of the Fe-Al metastable system produced by implantation of Fe + ions at 30 keV has been reported. The implant concentrations between 18-42 at percent have been chosen, in order to exceed the normal solid solubility of Fe in Al by about three orders of magnitude. Isothermal annealing has been done under vacuum (55 x 10 -6 Torr) at 400deg C and 570 deg C. The iron depth profiles have been determined, by Rutherford backscattering of 2 MeV He + ions. It has been found that 1) as annealing proceeds, all specimens show rapid enhanced diffusion initially (upto about 30 m), followed by a much slower diffusion as iron ions migrate inwards (2) at implant concentrations 23 at percent, double peaks appear in iron depth profiles, followed by rapid migration of diffused iron towards surface and (3) at still higher anneal times, the out-diffused iron moves inward again. This kind of out-diffusion behaviour in a metallic system has not been reported earlier in the literature. Also, the presence of Fe 4 Al 13 has been identified as terminal phase, using x-ray diffraction techniques. (K.B.)

Crystal structure of 2-methyl-1H-imidazol-3-ium hydrogen oxalate dihydrate

Directory of Open Access Journals (Sweden)

Mouhamadou Birame Diop

2016-08-01

Full Text Available Single crystals of the title molecular salt, C4H7N2+·HC2O4−·2H2O, were isolated from the reaction of 2-methyl-1H-imidazole and oxalic acid in a 1:1 molar ratio in water. In the crystal, the cations and anions are positioned alternately along an infinite [010] ribbon and linked together through bifurcated N—H...(O,O hydrogen bonds. The water molecules of crystallization link the chains into (10-1 bilayers, with the methyl groups of the cations organized in an isotactic manner.

Quantum-limited heat conduction over macroscopic distances

Science.gov (United States)

Partanen, Matti; Tan, Kuan Yen; Govenius, Joonas; Lake, Russell E.; Mäkelä, Miika K.; Tanttu, Tuomo; Möttönen, Mikko

2016-05-01

The emerging quantum technological apparatuses, such as the quantum computer, call for extreme performance in thermal engineering. Cold distant heat sinks are needed for the quantized electric degrees of freedom owing to the increasing packaging density and heat dissipation. Importantly, quantum mechanics sets a fundamental upper limit for the flow of information and heat, which is quantified by the quantum of thermal conductance. However, the short distance between the heat-exchanging bodies in the previous experiments hinders their applicability in quantum technology. Here, we present experimental observations of quantum-limited heat conduction over macroscopic distances extending to a metre. We achieved this improvement of four orders of magnitude in the distance by utilizing microwave photons travelling in superconducting transmission lines. Thus, it seems that quantum-limited heat conduction has no fundamental distance cutoff. This work establishes the integration of normal-metal components into the framework of circuit quantum electrodynamics, which provides a basis for the superconducting quantum computer. Especially, our results facilitate remote cooling of nanoelectronic devices using faraway in situ-tunable heat sinks. Furthermore, quantum-limited heat conduction is important in contemporary thermodynamics. Here, the long distance may lead to ultimately efficient mesoscopic heat engines with promising practical applications.

Structure of eight molecular salts assembled from noncovalent bonding between carboxylic acids, imidazole, and benzimidazole

Science.gov (United States)

Jin, Shouwen; Zhang, Huan; Liu, Hui; Wen, Xianhong; Li, Minghui; Wang, Daqi

2015-09-01

Eight organic salts of imidazole/benzimidazole have been prepared with carboxylic acids as 2-methyl-2-phenoxypropanoic acid, α-ketoglutaric acid, 5-nitrosalicylic acid, isophthalic acid, 4-nitro-phthalic acid, and 3,5-dinitrosalicylic acid. The eight crystalline forms reported are proton-transfer compounds of which the crystals and compounds were characterized by X-ray diffraction analysis, IR, mp, and elemental analysis. These structures adopted hetero supramolecular synthons, with the most common R22(7) motif observed at salts 2, 3, 5, 6 and 8. Analysis of the crystal packing of 1-8 suggests that there are extensive strong Nsbnd H⋯O, and Osbnd H⋯O hydrogen bonds (charge assisted or neutral) between acid and imidazolyl components in all of the salts. Except the classical hydrogen bonding interactions, the secondary propagating interactions also play important roles in structure extension. This variety, coupled with the varying geometries and number of acidic groups of the acids utilized, has led to the creation of eight supramolecular arrays with 1D-3D structure. The role of weak and strong noncovalent interactions in the crystal packing is analyzed. The results presented herein indicate that the strength and directionality of the Nsbnd H⋯O, and Osbnd H⋯O hydrogen bonds between acids and imidazole/benzimidazole are sufficient to bring about the formation of organic salts.

Iron and stony-iron meteorites

DEFF Research Database (Denmark)

Benedix, Gretchen K.; Haack, Henning; McCoy, T. J.

2014-01-01

Without iron and stony-iron meteorites, our chances of ever sampling the deep interior of a differentiated planetary object would be next to nil. Although we live on a planet with a very substantial core, we will never be able to sample it. Fortunately, asteroid collisions provide us with a rich...... sampling of the deep interiors of differentiated asteroids. Iron and stony-iron meteorites are fragments of a large number of asteroids that underwent significant geological processing in the early solar system. Parent bodies of iron and some stony-iron meteorites completed a geological evolution similar...... to that continuing on Earth – although on much smaller length- and timescales – with melting of the metal and silicates; differentiation into core, mantle, and crust; and probably extensive volcanism. Iron and stony-iron meteorites are our only available analogues to materials found in the deep interiors of Earth...

Non-trivial role of interlayer cation states in iron-based superconductors

Science.gov (United States)

Valenti, Roser; Guterding, Daniel; Jeschke, Harald O.; Glasbrenner, J. K.; Bascones, E.; Mazin, I. I.

Unconventional superconductivity in iron pnictides and chalcogenides has been suggested to be controlled by the interplay of low-energy antiferromagnetic spin fluctuations and the particular topology of the Fermi surface in these materials. Under this assumption, one would expect the large class of isostructural and isoelectronic iron germanide compounds to be good superconductors, but they aren't. In this talk we will argue that superconductivity in iron germanides is suppressed by strong ferromagnetic tendencies, which surprisingly do not originate from changes in bond-angles or bond-distances with respect to iron pnictides, but are due to changes in the electronic structure in a wide range of energies happening upon substitution of atom species (As by Ge and the corresponding spacer cations). We will discuss the implications of these results in the general context of Fe-based superconductors. Funding by the Deutsche Forschungsgemeinschaft is acknowledged.

Bromidotetra?kis?(1H-2-ethyl-5-methyl?imidazole-?N 3)copper(II) bromide

OpenAIRE

Godlewska, Sylwia; Baranowska, Katarzyna; Socha, Joanna; Do??ga, Anna

2011-01-01

The CuII ion in the title compound, [CuBr(C6H10N2)4]Br, is coordinated in a square-based-pyramidal geometry by the N atoms of four imidazole ligands and a bromide anion in the apical site. Both the CuII and Br− atoms lie on a crystallographic fourfold axis. In the crystal, the [CuBr(C6H10N2)4]+ complex cations are linked to the uncoordinated Br− anions (site symmetry overline{4}) by N—H...Br hydrogen bonds, generating a three-dimensional network. The ethyl group ...

Syntheses and structure characterization of ten acid-base hybrid crystals based on imidazole derivatives and mineral acids

Science.gov (United States)

Hu, Kaikai; Deng, Bowen; Jin, Shouwen; Ding, Aihua; Jin, Shide; Zhu, Jin; Zhang, Huan; Wang, Daqi

2018-04-01

Cocrystallization of the imidazole derivatives with a series of mineral acids gave a total of ten hybrid salts with the compositions: [(H2bzm)(Cl)2·3H2O] (1), [(H2bzm)(ClO4)2] (2), [(H2bze)(Cl)2·2H2O] (3), [(H2bze)(Br)2·2H2O] (4), [(H2bzp)(Cl)2·4H2O] (5), [(H2bzp)(Br)2·4H2O] (6), (2-(imidazol-1-yl)-1-phenylethanone): (phosphoric acid) [(Himpeta)+(H2PO4)-] (7), [(H2impd)(Br)2] (8), [(H2impd)(ClO4)2] (9), and [(Hbzml)(Cl)] (10). The ten salts have been characterised by X-ray diffraction analysis, IR, and elemental analysis, and the melting points of all the salts were also reported. And their structural and supramolecular aspects are fully analyzed. The result reveals that among the ten investigated crystals the ring N atoms of the imidazole are protonated when the acids are deprotonated, and the crystal packing is interpreted in terms of the strong charge-assisted classical H-bonds between the NH+ and deprotonated acidic groups. Further analysis of the crystal packing of the salts indicated that a different set of additional CHsbnd O, CH2sbnd O, CHsbnd Cl, CH2sbnd Cl, CHsbnd N, CHsbnd Br, CH2sbnd Br, Osbnd O, O-π, Br-π, CH-π, and π-π associations contribute to the stabilization and expansion of the total high-dimensional frameworks. For the coexistence of the various weak nonbonding interactions these structures adopted homo or hetero supramolecular synthons or both. Some classical supramolecular synthons, such as R21(7), R22(7), R22(8), and R42(8), usually observed in the organic solids, were again shown to be involved in constructing some of these H-bonding networks.

Site-to-Source Finite Fault Distance Probability Distribution in Probabilistic Seismic Hazard and the Relationship Between Minimum Distances

Science.gov (United States)

Ortega, R.; Gutierrez, E.; Carciumaru, D. D.; Huesca-Perez, E.

2017-12-01

We present a method to compute the conditional and no-conditional probability density function (PDF) of the finite fault distance distribution (FFDD). Two cases are described: lines and areas. The case of lines has a simple analytical solution while, in the case of areas, the geometrical probability of a fault based on the strike, dip, and fault segment vertices is obtained using the projection of spheres in a piecewise rectangular surface. The cumulative distribution is computed by measuring the projection of a sphere of radius r in an effective area using an algorithm that estimates the area of a circle within a rectangle. In addition, we introduce the finite fault distance metrics. This distance is the distance where the maximum stress release occurs within the fault plane and generates a peak ground motion. Later, we can apply the appropriate ground motion prediction equations (GMPE) for PSHA. The conditional probability of distance given magnitude is also presented using different scaling laws. A simple model of constant distribution of the centroid at the geometrical mean is discussed, in this model hazard is reduced at the edges because the effective size is reduced. Nowadays there is a trend of using extended source distances in PSHA, however it is not possible to separate the fault geometry from the GMPE. With this new approach, it is possible to add fault rupture models separating geometrical and propagation effects.

Synthesis of triazole-based and imidazole-based zinc catalysts

Energy Technology Data Exchange (ETDEWEB)

Valdez, Carlos A.; Satcher, Jr., Joe H.; Aines, Roger D.; Baker, Sarah E.

2013-03-12

Various methods and structures of complexes and molecules are described herein related to a zinc-centered catalyst for removing carbon dioxide from atmospheric or aqueous environments. According to one embodiment, a method for creating a tris(triazolyl)pentaerythritol molecule includes contacting a pentaerythritol molecule with a propargyl halide molecule to create a trialkyne molecule, and contacting the trialkyne molecule with an azide molecule to create the tris(triazolyl)pentaerythritol molecule. In another embodiment, a method for creating a tris(imidazolyl)pentaerythritol molecule includes alkylating an imidazole 2-carbaldehyde molecule to create a monoalkylated aldehyde molecule, reducing the monoalkylated aldehyde molecule to create an alcohol molecule, converting the alcohol molecule to create an alkyl halide molecule using thionyl halide, and reacting the alkyl halide molecule with a pentaerythritol molecule to create a tris(imidazolyl)pentaerythritol molecule. In another embodiment, zinc is bound to the tris(triazolyl)pentaerythritol molecule to create a zinc-centered tris(triazolyl)pentaerythritol catalyst for removing carbon dioxide from atmospheric or aqueous environments.

Synthesis and XRD, FT-IR vibrational, UV-vis, and nonlinear optical exploration of novel tetra substituted imidazole derivatives: A synergistic experimental-computational analysis

Science.gov (United States)

Ahmad, Muhammad Saeed; Khalid, Muhammad; Shaheen, Muhammad Ashraf; Tahir, Muhammad Nawaz; Khan, Muhammad Usman; Braga, Ataualpa Albert Carmo; Shad, Hazoor Ahmad

2018-04-01

Heterocyclic compounds have potential applications in many fields of life. We synthesized novel tetra substituted imidazoles by four-component condensation of benzil, substituted aldehydes, substituted anilines and ammonium acetate as a source of ammonia and acetic acid as the solvent. Their chemical structures were resolved through X-ray crystallographic and spectroscopic (Fourier transform IR and UV-vis) techniques. In addition to experimental analysis, density functional theory (DFT) calculations at the B3LYP/6-311 + G(d,p) level were performed on 4-bromo-2-(1-(4-methoxyphenyl)-4,5-diphenyl-1H-imidazole-2-yl)phenol (1), 4-bromo-2-(1-(1-naphthalen-yl)-4,5-diphenyl-1H-imidazole-2-yl)phenol (2), and 2-(1-(2-chlorophenyl)-4,5-diphenyl-1-H-imidazole-2-yl)-6-methoxyphenol (3) to obtain the optimized geometry and spectroscopic (Fourier transform IR and UV-vis) and non-linear optical properties. Frontier molecular orbital analysis was performed at the Hartee-Fock/6-311+g(d,p) and DFT/B3LYP/6-311+G(d,p) levels of theory. Natural bond orbital (NBO) and UV-vis spectral analyses were performed at the M06-2X/6-31+G(d,p) and time-dependent DFT/B3LYP/6-311+G(d,p) levels, respectively. Overall, the DFT findings show good agreement with the experimental data. The hyper conjugative interaction network, which is responsible for the stability of compounds 1, 2 and 3 was explored by the NBO approach. The global reactivity parameters were explored with use of the energy of the frontier molecular orbitals. DFT calculations predict the first-order hyperpolarizabilities of compounds 1, 2 and 3 are 294.89 × 10-30, 219.45 × 10-30 and 146.77 × 10-30 esu, respectively. A two-state model was used to describe the non-linear optical properties of the compounds investigated.

Preparation of poly(vinyl alcohol) membranes grafted with N-vinyl imidazole/acrylic acid binary monomers

International Nuclear Information System (INIS)

Ajji, Zaki; Ali, Ali

2006-01-01

Poly(vinyl alcohol) films were grafted with two monomers using gamma radiation, acrylic acid and N-vinyl imidazole. The influence of different parameters on the grafting yield was investigated as: type of solvent and solvent composition, comonomer concentration and composition, addition of mineral acids, and irradiation dose. Water uptake in respect to the grafting yield was also evaluated. The ability of the grafted films to adsorb copper ions was elaborated and discussed for different grafting yields and ph values of the solution. (authors)

Iron Status in Chronic Heart Failure: Impact on Symptoms, Functional Class and Submaximal Exercise Capacity.

Science.gov (United States)

Enjuanes, Cristina; Bruguera, Jordi; Grau, María; Cladellas, Mercé; Gonzalez, Gina; Meroño, Oona; Moliner-Borja, Pedro; Verdú, José M; Farré, Nuria; Comín-Colet, Josep

2016-03-01

To evaluate the effect of iron deficiency and anemia on submaximal exercise capacity in patients with chronic heart failure. We undertook a single-center cross-sectional study in a group of stable patients with chronic heart failure. At recruitment, patients provided baseline information and completed a 6-minute walk test to evaluate submaximal exercise capacity and exercise-induced symptoms. At the same time, blood samples were taken for serological evaluation. Iron deficiency was defined as ferritin < 100 ng/mL or transferrin saturation < 20% when ferritin is < 800 ng/mL. Additional markers of iron status were also measured. A total of 538 heart failure patients were eligible for inclusion, with an average age of 71 years and 33% were in New York Heart Association class III/IV. The mean distance walked in the test was 285 ± 101 meters among those with impaired iron status, vs 322 ± 113 meters (P=.002). Symptoms during the test were more frequent in iron deficiency patients (35% vs 27%; P=.028) and the most common symptom reported was fatigue. Multivariate logistic regression analyses showed that increased levels of soluble transferrin receptor indicating abnormal iron status were independently associated with advanced New York Heart Association class (P < .05). Multivariable analysis using generalized additive models, soluble transferrin receptor and ferritin index, both biomarkers measuring iron status, showed a significant, independent and linear association with submaximal exercise capacity (P=.03 for both). In contrast, hemoglobin levels were not significantly associated with 6-minute walk test distance in the multivariable analysis. In patients with chronic heart failure, iron deficiency but not anemia was associated with impaired submaximal exercise capacity and symptomatic functional limitation. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Representing distance, consuming distance

DEFF Research Database (Denmark)

Larsen, Gunvor Riber

Title: Representing Distance, Consuming Distance Abstract: Distance is a condition for corporeal and virtual mobilities, for desired and actual travel, but yet it has received relatively little attention as a theoretical entity in its own right. Understandings of and assumptions about distance...... are being consumed in the contemporary society, in the same way as places, media, cultures and status are being consumed (Urry 1995, Featherstone 2007). An exploration of distance and its representations through contemporary consumption theory could expose what role distance plays in forming...

A Method for Improving Galactic Cepheid Reddenings and Distances

Energy Technology Data Exchange (ETDEWEB)

Madore, Barry F. [The Observatories Carnegie Institution for Science 813 Santa Barbara St., Pasadena, CA 91101 (United States); Freedman, Wendy L.; Moak, Sandy, E-mail: barry.f.madore@gmail.com, E-mail: sandymoak@gmail.com, E-mail: wfreedman@uchicago.edu [Dept. of Astronomy and Astrophysics, University of Chicago, Chicago, IL (United States)

2017-06-10

We present a new photometric method by which improved high-precision reddenings and true distance moduli can be determined to individual Galactic Cepheids once distance measurements are available. We illustrate that the relative positioning of stars in the Cepheid period–luminosity (PL) relation (Leavitt law) is preserved as a function of wavelength. This information then provides a powerful constraint for determining reddenings to individual Cepheids, as well as their distances. As a first step, we apply this method to the 59 Cepheids in the compilation of Fouqué et al. Updated reddenings, distance moduli (or parallaxes), and absolute magnitudes in seven (optical through near-infrared) bands are given. From these intrinsic quantities, multiwavelength PL and color–color relations are derived. We find that the V -band period–luminosity–color relation has an rms scatter of only 0.06 mag, so that individual Cepheid distances can be measured to 3%, compared with dispersions of 6 to 13% for the one-parameter K through B PL relations, respectively. This method will be especially useful in conjunction with the new accurate parallax sample upcoming from Gaia .

Increased rates of large‐magnitude explosive eruptions in Japan in the late Neogene and Quaternary

Science.gov (United States)

Sparks, R. S. J.; Wallace, L. M.; Engwell, S. L.; Scourse, E. M.; Barnard, N. H.; Kandlbauer, J.; Brown, S. K.

2016-01-01

Abstract Tephra layers in marine sediment cores from scientific ocean drilling largely record high‐magnitude silicic explosive eruptions in the Japan arc for up to the last 20 million years. Analysis of the thickness variation with distance of 180 tephra layers from a global data set suggests that the majority of the visible tephra layers used in this study are the products of caldera‐forming eruptions with magnitude (M) > 6, considering their distances at the respective drilling sites to their likely volcanic sources. Frequency of visible tephra layers in cores indicates a marked increase in rates of large magnitude explosive eruptions at ∼8 Ma, 6–4 Ma, and further increase after ∼2 Ma. These changes are attributed to major changes in tectonic plate interactions. Lower rates of large magnitude explosive volcanism in the Miocene are related to a strike‐slip‐dominated boundary (and temporary cessation or deceleration of subduction) between the Philippine Sea Plate and southwest Japan, combined with the possibility that much of the arc in northern Japan was submerged beneath sea level partly due to previous tectonic extension of northern Honshu related to formation of the Sea of Japan. Changes in plate motions and subduction dynamics during the ∼8 Ma to present period led to (1) increased arc‐normal subduction in southwest Japan (and resumption of arc volcanism) and (2) shift from extension to compression of the upper plate in northeast Japan, leading to uplift, crustal thickening and favorable conditions for accumulation of the large volumes of silicic magma needed for explosive caldera‐forming eruptions. PMID:27656115

Effects of reinforcer magnitude on responding under differential-reinforcement-of-low-rate schedules of rats and pigeons.

Science.gov (United States)

Doughty, Adam H; Richards, Jerry B

2002-07-01

Experiment I investigated the effects of reinforcer magnitude on differential-reinforcement-of-low-rate (DRL) schedule performance in three phases. In Phase 1, two groups of rats (n = 6 and 5) responded under a DRI. 72-s schedule with reinforcer magnitudes of either 30 or 300 microl of water. After acquisition, the water amounts were reversed for each rat. In Phase 2, the effects of the same reinforcer magnitudes on DRL 18-s schedule performance were examined across conditions. In Phase 3, each rat responded unider a DR1. 18-s schedule in which the water amotnts alternated between 30 and 300 microl daily. Throughout each phase of Experiment 1, the larger reinforcer magnitude resulted in higher response rates and lower reinforcement rates. The peak of the interresponse-time distributions was at a lower value tinder the larger reinforcer magnitude. In Experiment 2, 3 pigeons responded under a DRL 20-s schedule in which reinforcer magnitude (1-s or 6-s access to grain) varied iron session to session. Higher response rates and lower reinforcement rates occurred tinder the longer hopper duration. These results demonstrate that larger reinforcer magnitudes engender less efficient DRL schedule performance in both rats and pigeons, and when reinforcer magnitude was held constant between sessions or was varied daily. The present results are consistent with previous research demonstrating a decrease in efficiency as a function of increased reinforcer magnituide tinder procedures that require a period of time without a specified response. These findings also support the claim that DRI. schedule performance is not governed solely by a timing process.

Intensity-distance attenuation law in the continental Portugal using intensity data points

Science.gov (United States)

Le Goff, Boris; Bezzeghoud, Mourad; Borges, José Fernando

2013-04-01

Several attempts have been done to evaluate the intensity attenuation with the epicentral distance in the Iberian Peninsula [1, 2]. So far, the results are not satisfying or not using the intensity data points of the available events. We developed a new intensity law for the continental Portugal, using the macroseismic reports that provide intensity data points, instrumental magnitudes and instrumental locations. We collected 31 events from the Instituto Portugues do Mar e da Atmosfera (IPMA, Portugal; ex-IM), covering the period between 1909 and 1997, with a largest magnitude of 8.2, closed to the African-Eurasian plate boundary. For each event, the intensity data points are plotted versus the distance and different trend lines are achieved (linear, exponential and logarithmic). The better fits are obtained with the logarithmic trend lines. We evaluate a form of the attenuation equation as follow: I = c0(M) + c1(M).ln(R) (1) where I, M and R are, respectively, the intensity, the magnitude and the epicentral distance. To solve this equation, we investigate two methods. The first one consists in plotting the slope of the different logarithmic trends versus the magnitude, to estimate the parameter c1(M), and to evaluate how the intensity behaves in function of the magnitude. Another plot, representing the intercepts versus the magnitude, allows to determine the second parameter, c0(M). The second method consists in using the inverse theory. From the data, we recover the parameters of the model, using a linear inverse matrix. Both parameters, c0(M) and c1(M), are provided with their associated errors. A sensibility test will be achieved, using the macroseismic data, to estimate the resolution power of both methods. This new attenuation law will be used with the Bakun and Wentworth method [3] in order to reestimate the epicentral region and the magnitude estimation of the 1909 Benavente event. This attenuation law may also be adapted to be used in Probabilistic Seismic

The Segue K giant survey. II. A catalog of distance determinations for the Segue K giants in the galactic halo

International Nuclear Information System (INIS)

Xue, Xiang-Xiang; Rix, Hans-Walter; Ma, Zhibo; Morrison, Heather L.; Harding, Paul; Beers, Timothy C.; Ivans, Inese I.; Jacobson, Heather R.; Johnson, Jennifer; Lee, Young Sun; Lucatello, Sara; Rockosi, Constance M.; Sobeck, Jennifer S.; Yanny, Brian; Zhao, Gang; Allende Prieto, Carlos

2014-01-01

We present an online catalog of distance determinations for 6036 K giants, most of which are members of the Milky Way's stellar halo. Their medium-resolution spectra from the Sloan Digital Sky Survey/Sloan Extension for Galactic Understanding and Exploration are used to derive metallicities and rough gravity estimates, along with radial velocities. Distance moduli are derived from a comparison of each star's apparent magnitude with the absolute magnitude of empirically calibrated color-luminosity fiducials, at the observed (g – r) 0 color and spectroscopic [Fe/H]. We employ a probabilistic approach that makes it straightforward to properly propagate the errors in metallicities, magnitudes, and colors into distance uncertainties. We also fold in prior information about the giant-branch luminosity function and the different metallicity distributions of the SEGUE K-giant targeting sub-categories. We show that the metallicity prior plays a small role in the distance estimates, but that neglecting the luminosity prior could lead to a systematic distance modulus bias of up to 0.25 mag, compared to the case of using the luminosity prior. We find a median distance precision of 16%, with distance estimates most precise for the least metal-poor stars near the tip of the red giant branch. The precision and accuracy of our distance estimates are validated with observations of globular and open clusters. The stars in our catalog are up to 125 kpc from the Galactic center, with 283 stars beyond 50 kpc, forming the largest available spectroscopic sample of distant tracers in the Galactic halo.

Experimental and theoretical investigations on the inhibition of mild steel corrosion in the ground water medium using newly synthesised bipodal and tripodal imidazole derivatives

Energy Technology Data Exchange (ETDEWEB)

Gopi, D., E-mail: dhanaraj_gopi@yahoo.com [Department of Chemistry, Periyar University, Salem 636 011, Tamilnadu (India); Centre for Nanoscience and Nanotechnology, Periyar University, Salem 636 011, Tamilnadu (India); Sherif, El-Sayed M. [Center of Excellence for Research in Engineering Materials (CEREM), Advanced Manufacturing Institute, King Saud University, P.O. Box 800, Al-Riyadh 11421 (Saudi Arabia); Electrochemistry and Corrosion Laboratory, Department of Physical Chemistry, National Research Centre (NRC), Dokki, 12622 Cairo (Egypt); Surendiran, M. [Department of Chemistry, Periyar University, Salem 636 011, Tamilnadu (India); Jothi, M.; Kumaradhas, P. [Department of Physics, Periyar University, Salem 636 011, Tamilnadu (India); Kavitha, L. [Department of Physics, School of Basic and Applied Sciences, Central University of Tamilnadu, Thiruvarur 610 101, Tamilnadu (India)

2014-10-15

Two new imidazole derivatives, namely 1,4-bis(N-imidazolylmethyl)-2-5-dimethoxybenzene (BIDM) and 1,3,5-tris(N-imidazolylmethyl)-2,4,6-trimethoxybenzene (TITM), were synthesised and their effects on the inhibition of mild steel corrosion in ground water medium are reported. The study was carried out using gravimetric and electrochemical techniques in order to determine the corrosion inhibition efficiencies of the bipodal and tripodal structured imidazoles. Further, the quantum chemical calculations using density functional theory (DFT) gave a profound insight into the inhibitory action mechanism of BIDM and TITM and their calculation parameters, such as E{sub HOMO}, E{sub LUMO} and ΔE were in good agreement with the results of the experimental studies. BIDM and TITM exhibited lowest corrosion current densities of circa 7.5 μA cm{sup −2} and 4.1 μAcm{sup −2} at the optimum concentrations of 0.67 and 0.49 mM, respectively. All measurements thus confirmed that both BIDM and TITM behaved as good inhibitors for mild steel corrosion in ground water medium. - Highlights: • Synthesis of new imidazole derivatives-BIDM(bipodal) and TITM(tripodal) inhibitors. • Gravimetric analysis to investigate mild steel corrosion inhibition in ground water. • Electrochemical characterizations to substantiate results of weight loss method. • Quantum studies to analyse the chemical behavior, structure and substituent effect.

Experimental and theoretical investigations on the inhibition of mild steel corrosion in the ground water medium using newly synthesised bipodal and tripodal imidazole derivatives

International Nuclear Information System (INIS)

Gopi, D.; Sherif, El-Sayed M.; Surendiran, M.; Jothi, M.; Kumaradhas, P.; Kavitha, L.

2014-01-01

Two new imidazole derivatives, namely 1,4-bis(N-imidazolylmethyl)-2-5-dimethoxybenzene (BIDM) and 1,3,5-tris(N-imidazolylmethyl)-2,4,6-trimethoxybenzene (TITM), were synthesised and their effects on the inhibition of mild steel corrosion in ground water medium are reported. The study was carried out using gravimetric and electrochemical techniques in order to determine the corrosion inhibition efficiencies of the bipodal and tripodal structured imidazoles. Further, the quantum chemical calculations using density functional theory (DFT) gave a profound insight into the inhibitory action mechanism of BIDM and TITM and their calculation parameters, such as E HOMO , E LUMO and ΔE were in good agreement with the results of the experimental studies. BIDM and TITM exhibited lowest corrosion current densities of circa 7.5 μA cm −2 and 4.1 μAcm −2 at the optimum concentrations of 0.67 and 0.49 mM, respectively. All measurements thus confirmed that both BIDM and TITM behaved as good inhibitors for mild steel corrosion in ground water medium. - Highlights: • Synthesis of new imidazole derivatives-BIDM(bipodal) and TITM(tripodal) inhibitors. • Gravimetric analysis to investigate mild steel corrosion inhibition in ground water. • Electrochemical characterizations to substantiate results of weight loss method. • Quantum studies to analyse the chemical behavior, structure and substituent effect

LARGE MAGELLANIC CLOUD DISTANCE AND STRUCTURE FROM NEAR-INFRARED RED CLUMP OBSERVATIONS

International Nuclear Information System (INIS)

Koerwer, Joel F.

2009-01-01

We have applied the Infrared Survey Facility Magellanic Clouds Point-Source Catalog to the mapping of the red clump (RC) distance modulus across the Large Magellanic Cloud (LMC). Using the J- (1.25 μm) and H- (1.63 μm) band data to derive a reddening free luminosity function and a theoretical RC absolute magnitude from stellar evolution libraries, we estimate a distance modulus to the LMC of μ = 18.54 ± 0.06. The best fitting plane inclination, i, and the position angle of the line of nodes, φ, have little dependence on the assumed RC absolute magnitude; we find i = 23. 0 5 ± 0. 0 4 and φ = 154. 0 6 ± 1. 0 2. It was also noted that many fields included a significant asymptotic giant branch bump population that must be accounted for.

Large Magellanic Cloud Distance and Structure from Near-Infrared Red Clump Observations

Science.gov (United States)

Koerwer, Joel F.

2009-07-01

We have applied the Infrared Survey Facility Magellanic Clouds Point-Source Catalog to the mapping of the red clump (RC) distance modulus across the Large Magellanic Cloud (LMC). Using the J- (1.25 μm) and H- (1.63 μm) band data to derive a reddening free luminosity function and a theoretical RC absolute magnitude from stellar evolution libraries, we estimate a distance modulus to the LMC of μ = 18.54 ± 0.06. The best fitting plane inclination, i, and the position angle of the line of nodes, phi, have little dependence on the assumed RC absolute magnitude; we find i = 23fdg5 ± 0fdg4 and phi = 154fdg6 ± 1fdg2. It was also noted that many fields included a significant asymptotic giant branch bump population that must be accounted for.

β–Cyclodextrin–Propyl Sulfonic Acid Catalysed One-Pot Synthesis of 1,2,4,5-Tetrasubstituted Imidazoles as Local Anesthetic Agents

Directory of Open Access Journals (Sweden)

Yan Ran

2015-11-01

Full Text Available Some functionalized 1,2,4,5-tetrasubstituted imidazole derivatives were synthesized using a one-pot, four component reaction involving 1,2-diketones, aryl aldehydes, ammonium acetate and substituted aromatic amines. The synthesis has been efficiently carried out in a solvent free medium using β-cyclodextrin-propyl sulfonic acid as a catalyst to afford the target compounds in excellent yields. The local anesthetic effect of these derivatives was assessed in comparison to lidocaine as a standard using a rabbit corneal and mouse tail anesthesia model. The three most potent promising compounds were subjected to a rat sciatic nerve block assay where they showed considerable local anesthetic activity, along with minimal toxicity. Among the tested analogues, 4-(1-benzyl-4,5-diphenyl-1H-imidazol-2-yl-N,N-dimethylaniline (5g was identified as most potent analogue with minimal toxicity. It was further characterized by a more favourable therapeutic index than the standard.

Formation and transformation of a short range ordered iron carbonate precursor

DEFF Research Database (Denmark)

Dideriksen, Knud; Frandsen, Cathrine; Bovet, Nicolas

2015-01-01

(II) with varying pH produced broad peaks in X-ray diffraction and contained dominantly Fe and CO3 when probed with X-ray photoelectron spectroscopy. Reduced pair distribution function (PDF) analysis shows only peaks corresponding to interatomic distances below 15Å, reflecting a material with no long range...... structural order. Moreover, PDF peak positions differ from those for known iron carbonates and hydroxides. Mössbauer spectra also deviate from those expected for known iron carbonates and suggest a less crystalline structure. These data show that a previously unidentified iron carbonate precursor phase...... formed. Its coherent scattering domains determined from PDF analysis are slightly larger than for amorphous calcium carbonate, suggesting that the precursor could be nanocrystalline. Replica exchange molecular dynamics simulations of Fe-carbonate polynuclear complexes yield PDF peak positions that agree...

Use of imidazole 4,5-dicarboxylic acid in vanadium speciation

International Nuclear Information System (INIS)

Banerjee, D.; Mondal, B.C.; Das, D.; Das, A.K.

2003-01-01

A new resin has been synthesized by fictionalization of polystyrene-divinylbenzene (8 %) with imidazole 4,5-dicarboxylic acid through -N=N- bonding. The resulting resin has been characterized by elemental analysis, thermogravimetric analysis, infrared spectroscopy, hydrogen ion capacity and metal ion capacity. The speciation study of vanadium has been studied by using this resin and the maximum exchange capacity was found to be 0.45 mmol g -1 for V 4+ and that for V 5+ was 1.57 mmol g -1 at pH 3 for both. The eluents malonic acid and sodium hydroxide have been used for the selective separation of vanadium(IV) and vanadium(V) species respectively. The effects of diverse ions on the sorption and recovery of each species have been studied. Finally, the developed method has been applied for the speciation and determination of these two species in natural water samples. (author)

Frequency sensitive moment tensor inversion for light to moderate magnitude earthquakes in eastern Africa

Science.gov (United States)

Barth, A.; Wenzel, F.; Giardini, D.

2007-08-01

We provide a procedure for the routine determination of moment tensors from earthquakes with magnitudes as low as M W 4.4 using data recorded by only a few permanent seismic stations at regional to teleseismic distances. Waveforms are inverted for automatically determined frequency pass-bands that depend on source-receiver locations as well as the earthquake magnitude. Inversion results are stable against small variations in the frequency band and provide low data variances, i.e., a good fit between observed and modelled waveform traces. The total frequency band used for our procedure ranges from 10 mHz to 29 mHz (periods of 35 s to 100 s). This enables us to determine focal mechanisms for earthquakes that were not derived previously by routine procedures of CMT or other agencies. As a case study, we determine focal mechanism solutions of 38 light to moderate magnitude earthquakes in eastern Africa between 1995 and 2002.

Some thermodynamic aspects of the solubility of iron in sodium

International Nuclear Information System (INIS)

Awasthi, S.P.; Sundaresan, M.

1984-01-01

Because of the use of liquid sodium as a heat transfer fluid in fast breeder reactors, its interaction with Fe and some alloying elements, has assumed great importance. Solubility is an important manifestation of this interaction, but there exists in literature a wide divergence in the data on the solubility of iron, which is known to have an intimate relationship with temperature and the concentration of available oxygen in sodium. An attempt has been made, here, to arrive at the mechanism of the observed enhanced solubility of iron in presence of oxygen by analysing the available experimental isothermal and athermal data on solubilities in literature by computing the relevant thermodynamic parameters for various probable interactions in the Na-O-Fe system. From comparison of these with the sign and magnitude of the theoretically calculated thermodynamic values, it has been shown that the predominant iron species existing in liquid sodium in presence of higher concentrations of oxygen is the soluble compound Na 4 FeO 3 . The most probable mechanism of the enhanced solubility of iron can be explained in terms of a sequence involving the initial formation of iron oxide (FeO) in liquid sodium, followed by its conversion to the compound Na 4 FeO 3 . (author)

Superluminous supernovae as standardizable candles and high-redshift distance probes

Energy Technology Data Exchange (ETDEWEB)

Inserra, C.; Smartt, S. J., E-mail: c.inserra@qub.ac.uk [Astrophysics Research Centre, School of Mathematics and Physics, Queens University Belfast, Belfast BT7 1NN (United Kingdom)

2014-12-01

We investigate the use of type Ic superluminous supernovae (SLSN Ic) as standardizable candles and distance indicators. Their appeal as cosmological probes stems from their remarkable peak luminosities, hot blackbody temperatures, and bright rest-frame ultraviolet emission. We present a sample of 16 published SLSN, from redshifts 0.1 to 1.2, and calculate accurate K corrections to determine uniform magnitudes in 2 synthetic rest-frame filter bandpasses with central wavelengths at 400 nm and 520 nm. At 400 nm, we find an encouragingly low scatter in their uncorrected, raw mean magnitudes with M(400) = –21.86 ± 0.35 mag for the full sample of 16 objects. We investigate the correlation between their decline rates and peak magnitude and find that the brighter events appear to decline more slowly. In a manner similar to the Phillips relation for type Ia SNe (SNe Ia), we define a ΔM {sub 20} decline relation. This correlates peak magnitude and decline over 20 days and can reduce the scatter in standardized peak magnitudes to ±0.22 mag. We further show that M(400) appears to have a strong color dependence. Redder objects are fainter and also become redder faster. Using this peak magnitudecolor evolution relation, a surprisingly low scatter of between ±0.08 mag and ±0.13 mag can be found in peak magnitudes, depending on sample selection. However, we caution that only 8 to 10 objects currently have enough data to test this peak magnitudecolor evolution relation. We conclude that SLSN Ic are promising distance indicators in the high-redshift universe in regimes beyond those possible with SNe Ia. Although the empirical relationships are encouraging, the unknown progenitor systems, how they may evolve with redshift, and the uncertain explosion physics are of some concern. The two major measurement uncertainties are the limited numbers of low-redshift, well-studied objects available to test these relationships and internal dust extinction in the host galaxies.

Iron Refractory Iron Deficiency Anaemia: A Rare Cause of Iron Deficiency Anaemia

LENUS (Irish Health Repository)

McGrath, T

2018-01-01

We describe the case of a 17-month-old boy with a hypochromic microcytic anaemia, refractory to oral iron treatment. After exclusion of dietary and gastrointestinal causes of iron deficiency, a genetic cause for iron deficiency was confirmed by finding two mutations in the TMPRSS6 gene, consistent with a diagnosis of iron-refractory iron deficiency anaemia (IRIDA).

Effect of race distance on muscle oxygenation in short-track speed skating.

Science.gov (United States)

Hesford, Catherine M; Laing, Stewart; Cardinale, Marco; Cooper, Chris E

2013-01-01

Previous work identified an asymmetry in tissue desaturation changes in the left and right quadriceps muscles during on-ice skating at maximal speed in males. The effect of changing race distance on the magnitude of desaturation or leg asymmetry is unknown. Six elite male skaters (age = 23 ± 1.8 yr, height = 1.8 ± 0.1 m, mass = 80.1 ± 5.7 kg, midthigh skinfold thickness = 7 ± 2 mm) and four elite female skaters (age = 21 ± 4 yr, height = 1.6 ± 0.1 m, mass = 65.2 ± 4.3 kg, midthigh skinfold thickness = 10 ± 1 mm) were studied. Subjects completed time trials over three race distances. Blood lactate concentration and O2 uptake measurements were combined with near-infrared spectroscopy measures of muscle oxygenation (TSI) and blood volume (tHb) in the right and left vastus lateralis. Neither race distance nor gender had a significant effect on the magnitude of maximal muscle desaturation (ΔTSI(max)). Pattern of local changes in tHb during individual laps was dependent upon subtle differences in skating technique used for the different race distances. Linear regression analysis revealed asymmetry between the right and left leg desaturation in males during the final stages of each race distance, but not in females. At all race distances, local muscle desaturation reached maximal values much more quickly than global VO(2peak). The use of wearable near-infrared spectroscopy devices enabled measurement of muscle oxygenation during competitive race simulation, thus providing unique insight into the effects of velocity and technique changes on local muscle oxygenation. This may have implications for training and race pacing in speed skating.

No Correlation between Distorted Body Representations Underlying Tactile Distance Perception and Position Sense

Directory of Open Access Journals (Sweden)

Matthew R. Longo

2016-11-01

Full Text Available Both tactile distance perception and position sense are believed to require that immediate afferent signals be referenced to a stored representation of body size and shape (the body model. For both of these abilities, recent studies have reported that the stored body representations involved are highly distorted, at least in the case of the hand, with the hand dorsum represented as wider and squatter than it actually is. Here, we investigated whether individual differences in the magnitude of these distortions are shared between tactile distance perception and position sense, as would be predicted by the hypothesis that a single distorted body model underlies both tasks. We used established task to measure distortions of the represented shape of the hand dorsum. Consistent with previous results, in both cases there were clear biases to overestimate distances oriented along the medio-lateral axis of the hand compared to the proximo-distal axis. Moreover, within each task there were clear split-half correlations, demonstrating that both tasks show consistent individual differences. Critically, however, there was no correlation between the magnitudes of distortion in the two tasks. This casts doubt on the proposal that a common body model underlies both tactile distance perception and position sense.

Evaluation of lead-iron-phosphate glass as a high-level waste form

International Nuclear Information System (INIS)

Chick, L.A.; Bunnell, L.R.; Strachan, D.M.; Kissinger, H.E.; Hodges, F.N.

1986-01-01

The lead-iron-phosphate nuclear waste glass developed at Oak Ridge National Laboratory (ORNL) was evaluated for its potential as an improvement over the current reference waste form, borosilicate glass. Vitreous lead-iron-phosphate glass appears to have substantially better chemical durability than borosilicate glass. However, severe crystallization leading to deteriorated chemical durability would result if this glass were poured into large canisters as is presently done with borosilicate glass. Cesium leach rates from this crystallized material are orders of magnitude greater than those from borosilicate glass. Therefore, in order to realize the performance advantages of the lead-iron-phosphate material in a nuclear waste form, it would be necessary to process it so that it is rapidly cooled, thus retaining its vitreous structure. 22 refs., 4 figs., 4 tabs

The Solar Neighborhood. 35. Distances to 1404 M Dwarf Systems Within 25 PC in the Southern Sky

Science.gov (United States)

2015-01-01

reference, and 2MASS JHKs magnitudes. The table is divided into the 1404 systems within 25 pc (top) and the 344 systems beyond 25 pc (bottom). A number in... 2MASS JHKs magnitudes, as discussed in Section 4.1. The plate R59F magnitude is the second, more recent R epoch measurement of the two available in...the SuperCOSMOS Sky Survey. The term ccddist is used to indicate a distance estimate that combines CCD VRI and 2MASS JHKs magnitudes, as discussed in

Pure white OLED based on an organic small molecule: 2,6-Di(1H-benzo[d]imidazol-2-yl)pyridine

Science.gov (United States)

Liu, Jian

2015-10-01

2,6-Di(1H-benzo[d]imidazol-2-yl)pyridine (DBIP) was synthesized. The single-crystal structure of DBIP was resolved. DBIP-based OLED was fabricated. The electroluminescence for the device corresponds to a pure white emission. In addition, thermal stability, UV-vis, photoluminescence and electrochemical behaviors of DBIP were investigated as well.

Study by Moessbauer spectroscopy of the iron-dextran (Imferon)

International Nuclear Information System (INIS)

Araujo, S.I. de; Danon, J.

1985-01-01

The iron-dextran complexes (imferon) are very important in the anemia treatment resulting of the iron insufficiency. Recent studies by electron diffraction denoted that the imferon is structurally different of the ferritin, one protein which constitute the iron reserve substance in the organisms. However, the obtained data in the imferon by Moessbauer spectroscopy, in different temperature ranges (room, liquid nitrogen and liquid He), show a great resemblance between this compound and the ferritin. A Fe 3+ distorted octahedrical coordenation is observed in both compounds, agreeing with measurements done in ferritin by EXAFS. In spite of the concordant results, persist, nevertheless, some discrepancies. The ferritin seems to be a rather more ionic than the imferon, possibly due to the rather higher interatomic distance in the former compound. In these measurements, a field of 484,6 + - 5 KOe is found for the imferon which, compared with the field of 493 + - 10 KOe for ferritin, confirms to be the ferritin more ionic than the imferon. It is, however, a litle difference, when it is compared to the existent between the iron binary oxides β FeOOH and γFeOOH. (L.C.) [pt

DNA binding, cytotoxicity and apoptosis induction activity of a mixed-ligand copper(II) complex with taurine Schiff base and imidazole

Science.gov (United States)

Li, Mei; kong, Lin Lin; Gou, Yi; Yang, Feng; Liang, Hong

2014-07-01

A novel binuclear copper(II) complex (complex 1) with taurine Schiff base and imidazole has been synthesized and structurally characterized by single crystal X-ray diffraction, elemental analysis, ESI-MS spectrometry, UV-vis and IR spectroscopy. Single-crystal analysis revealed that 1 displays the sulfonate-bridged dinuclear copper(II) centers. Both copper atoms are five-coordinated and exhibit slightly distorted square pyramidal geometries. Each of copper atom is surrounded by three oxygen atoms and one nitrogen atom from different taurine Schiff base ligands, and one nitrogen atom from one imidazole ligand. The interaction between 1 and calf thymus DNA (CT-DNA) was investigated by UV-vis, fluorescence, circular dichroism (CD) spectra and agarose gel electrophoresis. The experimental results indicated that 1 could bind to CT-DNA via an intercalative mode and show efficient cleavage activity. In addition, 1 showed an antitumor effect on cell cycle and apoptosis. Flow cytometric analysis revealed that MGC-803 cells were arrested in the S phase after treatment with 1. Fluorescence microscopic observation indicated that 1 could induce apoptosis of MGC-803 cells.

A method to quickly test the emissivity with an infrared thermal imaging system within a small distance

Science.gov (United States)

Wang, Xuan-yu; Hu, Rui; Wang, Rui-xin

2015-10-01

A simple method has been set up to quickly test the emissivity with an infrared thermal imaging system within a small distance according to the theory of measuring temperature by infrared system, which is based on the Planck radiation law and Lambert-beer law. The object's temperature is promoted and held on by a heater while a temperature difference has been formed between the target and environment. The emissivity of human skin, galvanized iron plate, black rubber and liquid water has been tested under the condition that the emissivity is set in 1.0 and the testing distance is 1m. According to the invariance of human's body temperature, a testing curve is established to describe that the thermal imaging temperatures various with the emissivity which is set in from 0.9 to 1.0. As a result, the method has been verified. The testing results show that the emissivity of human skin is 0.95. The emissivity of galvanized iron plate, black rubber and liquid water decreases with the increase of object's temperature. The emissivity of galvanized iron plate is far smaller than the one of human skin, black rubber or water. The emissivity of water slowly linearly decreases with the increase of its temperature. By the study, within a small distance and clean atmosphere, the infrared emissivity of objects may be expediently tested with an infrared thermal imaging system according to the method, which is promoting the object's temperature to make it different from the environment temperature, then simultaneously measures the environmental temperature, the real temperature and thermal imaging temperature of the object when the emissivity is set in 1.0 and the testing distance is 1.0m.

Iron Polymerization and Arsenic Removal During In-Situ Iron Electrocoagulation in Synthetic Bangladeshi Groundwater

Science.gov (United States)

van Genuchten, C. M.; Pena, J.; Addy, S.; Gadgil, A.

2010-12-01

Millions of people worldwide are exposed to arsenic-contamination in groundwater drinking supplies. The majority of affected people live in rural Bangladesh. Electrocoagulation (EC) using iron electrodes is a promising arsenic removal strategy that is based on the generation of iron precipitates with a high affinity for arsenic through the electrochemical dissolution of a sacrificial iron anode. Many studies of iron hydrolysis in the presence of co-occurring ions in groundwater such as PO43-, SiO44-, and AsO43- suggest that these ions influence the polymerization and formation of iron oxide phases. However, the combined impact of these ions on precipitates generated by EC is not well understood. X-ray absorption spectroscopy (XAS) was used to examine EC precipitates generated in synthetic Bangladeshi groundwater (SBGW). The iron oxide structure and arsenic binding geometry were investigated as a function of EC operating conditions. As and Fe k-edge spectra were similar between samples regardless of the large range of current density (0.02, 1.1, 5.0, 100 mA/cm2) used during sample generation. This result suggests that current density does not play a large role in the formation EC precipitates in SBGW. Shell-by-shell fits of Fe K-edge data revealed the presence of a single Fe-Fe interatomic distance at approximately 3.06 Å. The absence of longer ranged Fe-Fe correlations suggests that EC precipitates consist of nano-scale chains (polymers) of FeO6 octahedra sharing equatorial edges. Shell-by-shell fits of As K-edge spectra show arsenic bound in primarily bidentate, binuclear corner sharing complexes. In this coordination geometry, arsenic prevents the formation of FeO6 corner-sharing linkages, which are necessary for 3-dimensional crystal growth. The individual and combined effects of other anions, such as PO43- and SiO44- present in SBGW are currently being investigated to determine the role of these ions in stunting crystal growth. The results provided by this

DISTANCES TO DARK CLOUDS: COMPARING EXTINCTION DISTANCES TO MASER PARALLAX DISTANCES

International Nuclear Information System (INIS)

Foster, Jonathan B.; Jackson, James M.; Stead, Joseph J.; Hoare, Melvin G.; Benjamin, Robert A.

2012-01-01

We test two different methods of using near-infrared extinction to estimate distances to dark clouds in the first quadrant of the Galaxy using large near-infrared (Two Micron All Sky Survey and UKIRT Infrared Deep Sky Survey) surveys. Very long baseline interferometry parallax measurements of masers around massive young stars provide the most direct and bias-free measurement of the distance to these dark clouds. We compare the extinction distance estimates to these maser parallax distances. We also compare these distances to kinematic distances, including recent re-calibrations of the Galactic rotation curve. The extinction distance methods agree with the maser parallax distances (within the errors) between 66% and 100% of the time (depending on method and input survey) and between 85% and 100% of the time outside of the crowded Galactic center. Although the sample size is small, extinction distance methods reproduce maser parallax distances better than kinematic distances; furthermore, extinction distance methods do not suffer from the kinematic distance ambiguity. This validation gives us confidence that these extinction methods may be extended to additional dark clouds where maser parallaxes are not available.

Electrical and magnetic behavior of iron doped nickel titanate (Fe{sup 3+}/NiTiO{sub 3}) magnetic nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Lenin, Nayagam; Karthik, Arumugam; Sridharpanday, Mathu; Selvam, Mohanraj; Srither, Saturappan Ravisekaran; Arunmetha, Sundarmoorthy; Paramasivam, Palanisamy; Rajendran, Venkatachalam, E-mail: veerajendran@gmail.com

2016-01-01

Iron doped nickel titanate (Fe{sup 3+}/NiTiO{sub 3}) ferromagnetic nanoparticles with different concentrations of Fe (0.2, 0.4, and 0.6 mol) were synthesized using precipitation route with precursor source such as nickel nitrate and iron nitrate solutions. The prepared magnetic nanopowders were investigated through X-ray diffraction (XRD), Fourier transform infrared, scanning electron microscope, X-ray fluorescence, Brunauer–Emmett–Teller, vibrating sample magnetometer, and electrochemical impedance spectroscopy to explore the structural, ferromagnetic, and dielectric properties. The obtained XRD pattern shows formation of iron doped nickel titanate in orthorhombic structure. The crystallite size ranges from 57 to 21 nm and specific surface area ranges from 11 to 137 m{sup 2} g{sup −1}. The hysteresis loops of nanomagnetic materials show ferromagnetic behavior with higher magnitude of coercivity (H{sub c}) 867–462 Oe. The impedance analysis of ferromagnetic materials explores the ferro-dielectric behavior with enhanced properties of Fe{sup 3+}/NiTiO{sub 3} nanoparticles at higher Fe content. - Highlights: • Iron doped nickel titanate magnetic nanoparticles. • Ferromagnetic magnetism behavior with higher magnitude of coercivity. • Dielectric behavior of ferromagnetic nanoparticles with increase of Fe content.

The shadow price of CO2 emissions in China's iron and steel industry.

Science.gov (United States)

Wang, Ke; Che, Linan; Ma, Chunbo; Wei, Yi-Ming

2017-11-15

As China becomes the world's largest energy consumer and CO 2 emitter, there has been a rapidly emerging literature on estimating China's abatement cost for CO 2 using a distance function approach. However, the existing studies have mostly focused on the cost estimates at macro levels (provinces or industries) with few examining firm-level abatement costs. No work has attempted to estimate the abatement cost of CO 2 emissions in the iron and steel industry. Although some have argued that the directional distance function (DDF) is more appropriate in the presence of bad output under regulation, the choice of directions is largely arbitrary. This study provides the most up-to-date estimate of the shadow price of CO 2 using a unique dataset of China's major iron and steel enterprises in 2014. The paper uses output quadratic DDF and investigates the impact of using different directional vectors representing different carbon mitigation strategies. The results show that the mean CO 2 shadow price of China's iron and steel enterprises is very sensitive to the choice of direction vectors. The average shadow prices of CO 2 are 407, 1226 and 6058Yuan/tonne respectively for the three different direction vectors. We also find substantial heterogeneity in the shadow prices of CO 2 emissions among China's major iron and steel enterprises. Larger, listed enterprises are found to be associated lower CO 2 shadow prices than smaller, unlisted enterprises. Copyright © 2017 Elsevier B.V. All rights reserved.

Dissolved iron anomaly in the deep tropical-subtropical Pacific: Evidence for long-range transport of hydrothermal iron

Science.gov (United States)

Wu, Jingfeng; Wells, Mark L.; Rember, Robert

2011-01-01

Dissolved iron profiles along a north-south transect along 158°W in the tropical Pacific show evidence of two deepwater anomalies. The first extends from Station ALOHA (22.78°N) to the equator at ˜1000-1500 m and lies below the maximum apparent oxygen utilization and nutrient (N, P) concentrations. The feature is not supported by vertical export processes, but instead corresponds with the lateral dilution field of δ 3He derived from the Loihi seamount, Hawaii, though a sediment source associated with the Hawaiian Island Chain cannot be entirely ruled out. The second, deeper (2000-3000 m) anomaly occurs in tropical South Pacific waters (7°S) and also does not correlate with the depths of maximum nutrient concentrations or apparent oxygen utilization, but it does coincide closely with δ 3He emanating from the East Pacific Rise, more than 5000 km to the east. We hypothesize that these anomalies represent the long-range (>2000 km) transport of hydrothermal iron residuals, stabilized against scavenging by complexation with excess organic ligands in the plume source regions. Such trace leakage of hydrothermal iron to distal plume regions would have been difficult to identify in most hydrothermal vent mapping studies because low analytical detection limits were not needed for the proximal plume regions. These findings suggest that hydrothermal activity may represent a major source of dissolved iron throughout the South Pacific deep basin today, as well as other regions having high mid-ocean spreading rates in the geologic past. In particular, we hypothesize that high spreading rates along the South Atlantic and Southern Ocean mid-oceanic ridges, combined with the upwelling ventilation of these distal hydrothermal plumes, may have increased ocean productivity and carbon export in the Southern Ocean. Assessing the magnitude and persistence of dissolved hydrothermal iron in basin scale deep waters will be important for understanding the marine biogeochemistry of iron

Scaling Relations of Local Magnitude versus Moment Magnitude for Sequences of Similar Earthquakes in Switzerland

KAUST Repository

Bethmann, F.; Deichmann, N.; Mai, Paul Martin

2011-01-01

Theoretical considerations and empirical regressions show that, in the magnitude range between 3 and 5, local magnitude, ML, and moment magnitude, Mw, scale 1:1. Previous studies suggest that for smaller magnitudes this 1:1 scaling breaks down

THE ABSOLUTE MAGNITUDES OF TYPE Ia SUPERNOVAE IN THE ULTRAVIOLET

International Nuclear Information System (INIS)

Brown, Peter J.; Roming, Peter W. A.; Ciardullo, Robin; Gronwall, Caryl; Hoversten, Erik A.; Pritchard, Tyler; Milne, Peter; Bufano, Filomena; Mazzali, Paolo; Elias-Rosa, Nancy; Filippenko, Alexei V.; Li Weidong; Foley, Ryan J.; Hicken, Malcolm; Kirshner, Robert P.; Gehrels, Neil; Holland, Stephen T.; Immler, Stefan; Phillips, Mark M.; Still, Martin

2010-01-01

We examine the absolute magnitudes and light-curve shapes of 14 nearby (redshift z = 0.004-0.027) Type Ia supernovae (SNe Ia) observed in the ultraviolet (UV) with the Swift Ultraviolet/Optical Telescope. Colors and absolute magnitudes are calculated using both a standard Milky Way extinction law and one for the Large Magellanic Cloud that has been modified by circumstellar scattering. We find very different behavior in the near-UV filters (uvw1 rc covering ∼2600-3300 A after removing optical light, and u ∼ 3000-4000 A) compared to a mid-UV filter (uvm2 ∼2000-2400 A). The uvw1 rc - b colors show a scatter of ∼0.3 mag while uvm2-b scatters by nearly 0.9 mag. Similarly, while the scatter in colors between neighboring filters is small in the optical and somewhat larger in the near-UV, the large scatter in the uvm2 - uvw1 colors implies significantly larger spectral variability below 2600 A. We find that in the near-UV the absolute magnitudes at peak brightness of normal SNe Ia in our sample are correlated with the optical decay rate with a scatter of 0.4 mag, comparable to that found for the optical in our sample. However, in the mid-UV the scatter is larger, ∼1 mag, possibly indicating differences in metallicity. We find no strong correlation between either the UV light-curve shapes or the UV colors and the UV absolute magnitudes. With larger samples, the UV luminosity might be useful as an additional constraint to help determine distance, extinction, and metallicity in order to improve the utility of SNe Ia as standardized candles.

Hydrogen effect on embrittlement of iron and steel

International Nuclear Information System (INIS)

Shved, M.M.

1981-01-01

Some existing hypothesis brittleness of metals are considered. The following explanation of reversible hydrogen brittleness is suggested: hydrogen presence in iron and steel brings about the increase in the critical shear stress and the yield stress at all stages of plastic deformation (hydrogen, blocking dislocations hinders plastic shears) and the decrease of rupture strength. Decreasing forces of interatomic interaction of the surface layer some scores interatomic distances thick, hydrogen decreases the resistance of normal stresses to its effect. Thus, whatever mechanism brings about the formation of the first cracks in the metal in the presence of absorbed hydrogen, they appear at lower outside applied stresses. In the framework of the model suggested one can explain experimentally observed changes of mechanical properties of iron and steel under hydrogen effect

Tumor Repression of VCaP Xenografts by a Pyrrole-Imidazole Polyamide.

Directory of Open Access Journals (Sweden)

Amanda E Hargrove

Full Text Available Pyrrole-imidazole (Py-Im polyamides are high affinity DNA-binding small molecules that can inhibit protein-DNA interactions. In VCaP cells, a human prostate cancer cell line overexpressing both AR and the TMPRSS2-ERG gene fusion, an androgen response element (ARE-targeted Py-Im polyamide significantly downregulates AR driven gene expression. Polyamide exposure to VCaP cells reduced proliferation without causing DNA damage. Py-Im polyamide treatment also reduced tumor growth in a VCaP mouse xenograft model. In addition to the effects on AR regulated transcription, RNA-seq analysis revealed inhibition of topoisomerase-DNA binding as a potential mechanism that contributes to the antitumor effects of polyamides in cell culture and in xenografts. These studies support the therapeutic potential of Py-Im polyamides to target multiple aspects of transcriptional regulation in prostate cancers without genotoxic stress.

Structure and Heme-Independent Peroxidase Activity of a Fully-Coordinated Mononuclear Mn(II) Complex with a Schiff-Base Tripodal Ligand Containing Three Imidazole Groups

Energy Technology Data Exchange (ETDEWEB)

Sarkar, Shuranjan; Lee, Hong In [Kyungpook National University, Daegu (Korea, Republic of); Moon, Do Hyun [Pohang Accelerator Laboratory, Pohang (Korea, Republic of); Lah, Myoung Soo [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

2010-11-15

New complex [Mn(II)H{sub 1.5}L]{sub 2}[Mn(II)H{sub 3}L]{sub 2}(ClO{sub 4}){sub 5}·3H{sub 2}O, where H{sub 3}L is tris{2-(4-imidazolyl)methyliminoethyl} amine (imtren), has been prepared by reacting manganese(II) perchlorate hexahydrate with the imtren ligand in methanol. X-ray crystallographic study revealed that the imtren ligand hexadentately binds to Mn(II) ion through the three Schiff-base imine N atoms and three imidazole N atoms with a distorted octahedral geometry, and the apical tertiary amine N atom of the ligand pseudo-coordinates to Mn(II), forming overall a pseudo-seven coordination environment. The hydrogen-bonds between imidazole and imidazolate of [Mn(II)H{sub 1.5}L]{sup 0.5+} complex ions are extended to build a 2D puckered network with trigonal voids. [Mn(II)H{sub 3}L]{sup 2+} complex ions constitutes another extended 2D puckered layer without hydrogen bonds. Two layers are wedged each other to constitute overall stack of the crystal. Peroxidase activity of complex 1 was examined by observing the oxidation of 2,2'-azinobis(3-ethylbenzothiazoline)- 6-sulfonic acid (ABTS) with hydrogen peroxide in the presence of complex 1. Generation of ABTS{sup +·} was observed by UV-vis and EPR spectroscopies, indicating that the complex 1, a fully-coordinated mononuclear Mn(II) complex with nitrogen-only ligand, has a heme-independent peroxidase activity.

Genetics Home Reference: iron-refractory iron deficiency anemia

Science.gov (United States)

... refractory iron deficiency anemia Iron-refractory iron deficiency anemia Printable PDF Open All Close All Enable Javascript ... expand/collapse boxes. Description Iron-refractory iron deficiency anemia is one of many types of anemia , which ...

Synthesis, single crystal X-ray, spectroscopic (FT-IR, UV-vis, fluorescence, 1H &13C NMR), computational (DFT/B3LYP) studies of some imidazole based picrates

Science.gov (United States)

Arockia doss, M.; Rajarajan, G.; Thanikachalam, V.; Selvanayagam, S.; Sridhar, B.

2018-04-01

2,4,5-triphenyl-1H-imidazol-3-ium picrate (1), 2-(4-fluorophenyl)-4,5-diphenyl-1H-imidazol-3-ium picrate (2), 2-(4-methylphenyl)-4,5-diphenyl-1H-imidazol-3-ium picrate (3) were synthesised. These compounds 1-3 were characterized by elemental, FT-IR, 1H NMR and 13C NMR analyses. The structure of compound 3 was further confirmed by single crystal X-ray diffraction. The studies reveal that the molecule is associated with weak Nsbnd H⋯O and Csbnd H⋯N and van der Waals interactions which are responsible for the formation and strengthening of supramolecular assembly. The nature of the interactions and their importance are explored using the Hirshfeld surface method. The physicochemical properties of the compounds 1-3 were evaluated by UV-vis spectroscopy, fluorescence spectroscopy, and thermogravimetric analysis. According to thermal data the salts possess excellent thermal stabilities with decomposition temperatures ranging from 220 to 280 °C. Second-harmonic generation (SHG) results exposed that the picrates 1-3 were about 1.13-1.50 times greater than potassium dihydrogen phosphate (KDP). Here we also used Density functional theory (DFT) calculations in order to investigate the opto-electronic properties. The obtained theoretical results validate with available experimental data.

Optical fiber chemiluminescence sensor for iron (II) ion based on immobilized luminol

International Nuclear Information System (INIS)

Alipao, Arthur A.; Sevilla, Fortunato III.

1999-01-01

A chemiluminescence (CL) sensor for iron (II) was developed based on the catalytic action of the analyte on the CL reaction between luminol and oxygen. The reagents were immobilized on a cellulose membrane and set on a reaction cell which was coupled by means of an optical fiber to a spectrofluorometer. The concentration of iron(II) was quantified by measuring the intensity of the light generated from the CL reaction. The response of the sensor system was rapid and highly reproducible. Good sensitivity was displayed by the sensor system over the five orders of magnitude of iron(II) ion concentration. The calibration curve consisted of two portions: (1) a linear range at lower concentrations (7.5 x 10 -7 M to 1.0 x 10 -4 M) exhibiting a positive slope arising from a catalytic action, and (2) a linear range at higher concentrations (5.0 x 10 -2 M to 2.5 x 10 -4 M) wherein the slope is negative due to an inhibitory action of iron(II) on the CL reaction. The sensor system was highly selective for iron(II) ions. (Author)

Exploring Microbial Iron Oxidation in Wetland Soils

Science.gov (United States)

Wang, J.; Muyzer, G.; Bodelier, P. L. E.; den Oudsten, F.; Laanbroek, H. J.

2009-04-01

Iron is one of the most abundant elements on earth and is essential for life. Because of its importance, iron cycling and its interaction with other chemical and microbial processes has been the focus of many studies. Iron-oxidizing bacteria (FeOB) have been detected in a wide variety of environments. Among those is the rhizosphere of wetland plants roots which release oxygen into the soil creating suboxic conditions required by these organisms. It has been reported that in these rhizosphere microbial iron oxidation proceeds up to four orders of magnitude faster than strictly abiotic oxidation. On the roots of these wetland plants iron plaques are formed by microbial iron oxidation which are involved in the sequestering of heavy metals as well organic pollutants, which of great environmental significance.Despite their important role being catalysts of iron-cycling in wetland environments, little is known about the diversity and distribution of iron-oxidizing bacteria in various environments. This study aimed at developing a PCR-DGGE assay enabling the detection of iron oxidizers in wetland habitats. Gradient tubes were used to enrich iron-oxidizing bacteria. From these enrichments, a clone library was established based on the almost complete 16s rRNA gene using the universal bacterial primers 27f and 1492r. This clone library consisted of mainly α- and β-Proteobacteria, among which two major clusters were closely related to Gallionella spp. Specific probes and primers were developed on the basis of this 16S rRNA gene clone library. The newly designed Gallionella-specific 16S rRNA gene primer set 122f/998r was applied to community DNA obtained from three contrasting wetland environments, and the PCR products were used in denaturing gradient gel electrophoresis (DGGE) analysis. A second 16S rRNA gene clone library was constructed using the PCR products from one of our sampling sites amplified with the newly developed primer set 122f/998r. The cloned 16S rRNA gene

Mutagenicity of 1-Ethyl-2,4,5-triphenyl-1H-imidazole and Six Derivatives in Salmonella typhimurium

OpenAIRE

KORKMAZ, Ferhan; Korkmaz, Ferhan; MERCANGOZ, Ayse

2010-01-01

 Newly synthesized 1-Ethyl-2,4,5-triphenyl-1H-imidazole and its six derivatives were tested by Ames assay. In order to reveal the mutagenic activities of the compounds, two different mutant strains of Salmonella typhimurium (TA98 and TA100) were used in an Ames assay with/without S9 microsomal fraction from rat liver. It was found that the compounds have no mutagenic activities.          &nb...

Effect of dietary iron source and iron status on iron bioavailability tests in the rat

International Nuclear Information System (INIS)

Zhang, D.; Hendricks, D.G.; Mahoney, A.W.

1986-01-01

Weanling male rats were made anemic in 7 days by feeding a low iron diet and bleeding. Healthy rats were fed the low iron diet supplemented with ferrous sulfate (29 ppm Fe). Each group was subdivided and fed for 10 days on test diets containing about 29 ppm iron that were formulated with meat:spinach mixtures or meat:soy mixtures to provided 100:0, 75:25, 50:50, 25:75, or 0:100% of the dietary iron from these sources or from a ferrous sulfate diet. After 3 days on the diets all rats were dosed orally with 2 or 5 micro curries of 59 Fe after a 18 hour fast and refeeding for 1.5 hours. Iron status influenced liver iron, carcass iron, liver radio activity and percent of radioactive dose retained. Diet influenced fecal iron and apparent absorption of iron. In iron bioavailability studies assessment methodology and iron status of the test subject greatly influences the estimates of the value of dietary sources of iron

Synthesis of O-[2-[18F]fluoro-3-(2-nitro-1H-imidazole-1-yl)propyl]tyrosine ([18F]FNT]) as a new class of tracer for imaging hypoxia

International Nuclear Information System (INIS)

Noeen Malik; Xian Lin; Christoph Solbach; Hans-Juergen Machulla; Bin Shen; Gerald Reischl; Wolfgang Voelter

2012-01-01

For detection of hypoxic tumor tissue, all radiotracers synthesized until now, are based on the concept that cellular uptake is being controlled by diffusion. As a new approach, we chose the concept to have the tracer hypothetically transported into the cells by well known carrier systems like the amino acid transporters. For this purpose, radiosynthesis of O-[2-[ 18 F]fluoro-3-(2-nitro-1H-imidazole-1yl)propyl]tyrosine ([18F]FNT]) was carried out from methyl 2-(benzyloxycarbonyl)-3-(4-3-(2-nitro-1H-imidazol-1-yl) -2-(tosyloxy)propoxy) phenyl)propanoate via no-carrier-added nucleophilic aliphatic substitution. After labelling, 81 ± 0.9% of labelled intermediate i.e. methyl 2-(benzyloxycarbonyl)-3-(4-(2-[ 18 F]fluoro-3- (2-nitro-1H-imidazole-1-yl)propoxy) phenyl)propanoate was obtained at 140 deg C. At the end of radiosynthesis, [ 18 F]FNT was obtained in an overall radiochemical yield of 40 ± 0.9% (not decay corrected) within 90 min in a radiochemical purity of >98% in a formulation ready for application in the clinical studies for PET imaging of hypoxia. (author)

Synthesis, characterization and catalytic application of silica supported tin oxide nanoparticles for synthesis of 2,4,5-tri and 1,2,4,5-tetrasubstituted imidazoles under solvent-free conditions

Directory of Open Access Journals (Sweden)

Ashok V. Borhade

2017-02-01

Full Text Available Highly efficient and eco-friendly, one pot synthesis of 1,2,4,5-tetra substituted imidazoles and 2,4,5-trisubstituted imidazoles was reported under solvent free conditions using nanocrystalline silica supported tin oxide (SiO2:SnO2 as a catalyst with excellent yield. The present methodology offers several advantages such as mild reaction conditions, short reaction time, good yield, high purity of product, recyclable catalyst without a noticeable decrease in catalytic activity and can be used for large scale synthesis. The synthesized SiO2:SnO2 nanocrystalline catalyst was characterized by XRD, BET surface area and TEM techniques.

Nutritional iron deficiency anemia: magnitude and its predictors among school age children, southwest Ethiopia: a community based cross-sectional study.

Science.gov (United States)

Desalegn, Amare; Mossie, Andualem; Gedefaw, Lealem

2014-01-01

Iron deficiency anemia (IDA) is a global public health problem among school age children, which retards psychomotor development and impairs cognitive performance. There is limited data on prevalence and risk factors for IDA. The aim of this study was to determine the prevalence, severity, and predictors of nutritional IDA in school age children in Southwest Ethiopia. A community based cross-sectional study was conducted in Jimma Town, Southwest Ethiopia from April to July 2013. A total of 616 school children aged 6 to 12 years were included in the study using multistage sampling technique. A structured questionnaire was used to collect sociodemographic data. Five milliliter venous blood was collected from each child for hematological examinations. Anemia was defined as a hemoglobin level lower than 11.5 g/dl and 12 g/dl for age group of 5-11 years and 12-15 years, respectively. Iron deficiency anemia was defined when serum iron and ferritin levels are below 10 µmol/l and 15 µg/dl, respectively. Moreover, fresh stool specimen was collected for diagnosis of intestinal parasitic infection. Stained thick and thin blood films were examined for detection of Plasmodium infection and study of red blood cell morphology. Dietary patterns of the study subjects were assessed using food frequency questionnaire and anthropometric measurements were done. Data were analyzed using SPSS V-20.0 for windows. Overall, prevalence of anemia was 43.7%, and that of IDA was 37.4%. Not-consuming protein source foods [AOR = 2.30, 95%CI(1.04,5.14)], not-consuming dairy products [AOR = 1.83, 95%CI(1.14,5.14)], not-consuming discretionary calories [AOR = 2.77, 95%CI(1.42,5.40)], low family income [AOR = 6.14, 95%CI(2.90,12.9)] and intestinal parasitic infections [AOR = 1.45, 95%CI(1.23, 5. 27)] were predictors of IDA. Iron deficiency anemia is a moderate public health problem in the study site. Dietary deficiencies and intestinal parasitic infections were predictors of IDA

Nutritional iron deficiency anemia: magnitude and its predictors among school age children, southwest Ethiopia: a community based cross-sectional study.

Directory of Open Access Journals (Sweden)

Amare Desalegn

Full Text Available Iron deficiency anemia (IDA is a global public health problem among school age children, which retards psychomotor development and impairs cognitive performance. There is limited data on prevalence and risk factors for IDA.The aim of this study was to determine the prevalence, severity, and predictors of nutritional IDA in school age children in Southwest Ethiopia.A community based cross-sectional study was conducted in Jimma Town, Southwest Ethiopia from April to July 2013. A total of 616 school children aged 6 to 12 years were included in the study using multistage sampling technique. A structured questionnaire was used to collect sociodemographic data. Five milliliter venous blood was collected from each child for hematological examinations. Anemia was defined as a hemoglobin level lower than 11.5 g/dl and 12 g/dl for age group of 5-11 years and 12-15 years, respectively. Iron deficiency anemia was defined when serum iron and ferritin levels are below 10 µmol/l and 15 µg/dl, respectively. Moreover, fresh stool specimen was collected for diagnosis of intestinal parasitic infection. Stained thick and thin blood films were examined for detection of Plasmodium infection and study of red blood cell morphology. Dietary patterns of the study subjects were assessed using food frequency questionnaire and anthropometric measurements were done. Data were analyzed using SPSS V-20.0 for windows.Overall, prevalence of anemia was 43.7%, and that of IDA was 37.4%. Not-consuming protein source foods [AOR = 2.30, 95%CI(1.04,5.14], not-consuming dairy products [AOR = 1.83, 95%CI(1.14,5.14], not-consuming discretionary calories [AOR = 2.77, 95%CI(1.42,5.40], low family income [AOR = 6.14, 95%CI(2.90,12.9] and intestinal parasitic infections [AOR = 1.45, 95%CI(1.23, 5. 27] were predictors of IDA.Iron deficiency anemia is a moderate public health problem in the study site. Dietary deficiencies and intestinal parasitic infections were

alpha,beta-unsaturated 2-acyl imidazoles as a practical class of dienophiles for the DNA-Based catalytic asymmetric diels-alder reaction in water

NARCIS (Netherlands)

Boersma, A.J.; Feringa, B.L.; Roelfes, G.

2007-01-01

alpha,beta-Unsaturated 2-acyl imidazoles are a novel and practical class of dienophiles for the DNA-based catalytic asymmetric Diels-Alder reaction in water. The Diels-Alder products are obtained with very high diastereoselectivities and enantioselectivities in the range of 83-98%. The catalytic

Comparative and non-comparative studies of the efficacy and tolerance of tioconazole cream 1% versus another imidazole and/or placebo in neonates and infants with candidal diaper rash and/or impetigo.

Science.gov (United States)

Gibbs, D L; Kashin, P; Jevons, S

1987-01-01

Eleven open multicentre studies were conducted to evaluate the efficacy of tioconazole cream 1% as a treatment for diaper rash with or without fungal (Candida) involvement, or impetigo in neonates and infants. In the dermal candidiasis/diaper rash group, 320 patients had either tioconazole (n = 220), a comparative imidazole (n = 43), or vehicle cream (n = 57) applied to the affected area twice daily. Twenty-one impetigo patients had only tioconazole cream 1% applied three times daily to lesions. The overall cure rate (patients with both clinical and mycological cure) at the end of treatment for tioconazole treated patients was 78%, for the comparative imidazole group it was 76% and for vehicle cream it was 39%. At the long-term follow-up evaluation approximately 6 weeks after treatment for patients with diaper rash, the overall cure rate was about the same in both tioconazole- and comparative imidazole-treated patients (87% and 90%, respectively), and 14% in patients using vehicle cream. Side-effects were coincident with disease symptoms and consisted primarily of erythema localized to the treatment area; they occurred in 5.4% (13/241) of the patients who received tioconazole and in 21% (9/43) of the patients who received comparative imidazole (econazole or miconazole). No side-effects were reported in this open study for the 57 patients who used vehicle cream. The results of these studies show that tioconazole cream 1% is safe and effective for the treatment of neonates and infants with dermal candidiasis, diaper rash and impetigo.

Iron absorption in relation to iron status

International Nuclear Information System (INIS)

Magnusson, B.; Bjoern-Rasmussen, E.; Hallberg, L.; Rossander, L.

1981-01-01

The absorption from a 3 mg dose of ferrous iron was measured in 250 male subjects. The absorption was related to the log concentration of serum ferritin in 186 subjects of whom 99 were regular blood donors (r= -0.76), and to bone marrow haemosiderin grading in 52 subjects with varying iron status. The purpose was to try and establish a percentage absorption from such a dose that is representative of subjects who are borderline iron deficient. This information is necessary for food iron absorption studies in order (1) to calculate the absorption of iron from the diet at a given iron status and (2) compare the absorption of iron from different meals studied in different groups of subjects by different investigarors. The results suggest that an absorption of about 40% of a 3 mg reference dose of ferrous iron is given in a fasting state, roughly corresponds to the absorption in borderline-iron-deficient subjects. The results indicate that this 40% absorption value corresponds to a serum ferritin level of 30 μg/l and that food iron absorption in a group of subjects should be expressed preferably as the absorption corresponding to a reference-dose absorption of 45%, or possibly a serum ferritin level of 30 μg/l. (author)

A novel poly(propylene-co-imidazole) based biofuel cell: System optimization and operation for energy generation

Energy Technology Data Exchange (ETDEWEB)

Kilic, Muhammet Samet [Department of Chemistry, Bulent Ecevit University, 67100 Zonguldak (Turkey); Korkut, Seyda, E-mail: s.korkut@beun.edu.tr [Department of Environmental Engineering, Bulent Ecevit University, 67100 Zonguldak (Turkey); Hazer, Baki [Department of Chemistry, Bulent Ecevit University, 67100 Zonguldak (Turkey)

2015-02-01

This study describes the construction of an enzymatic fuel cell comprised of novel gold nanoparticles embedded poly(propylene-co-imidazole) coated anode and cathode. Working electrode fabrication steps and operational conditions for the fuel cell have been optimized to get enhanced power output. Electrical generation capacity of the optimized cell was tested by using the municipal wastewater sample. The enzymatic fuel cell system reached to maximum power density with 1 μg and 8 μg of polymer quantity and bilirubin oxidase on electrode surface, respectively. The maximum power output was calculated to be 5 μW cm{sup −2} at + 0.56 V (vs. Ag/AgCl) in phosphate buffer (pH 7.4, 100 mM, 20 °C) by the addition of 15 mM of glucose as a fuel source. The optimized enzymatic fuel cell generated a power density of 0.46 μW cm{sup −2} for the municipal wastewater sample. Poly(propylene-co-imidazole) was easily used for a fuel cell system owing to its metallic nanoparticle content. The developed fuel cell will play a significant role for energy conversion by using glucose readily found in wastewater and in vivo mediums. - Highlights: • Gold nanoparticles provided faster electron transfer in the circuit. • The maximum power density of 5 μW cm{sup −2} was generated at + 0.56 V cell potential. • The cell can be easily operated for in vivo mediums.

2-(2-Hydroxyphenyl)imidazole-based four-coordinate organoboron compounds with efficient deep blue photoluminescence and electroluminescence.

Science.gov (United States)

Zhang, Zhenyu; Zhang, Zuolun; Zhang, Hongyu; Wang, Yue

2017-12-19

Two new four-coordinate organoboron compounds with 2-(2-hydroxyphenyl)imidazole derivatives as the chelating ligands have been synthesized. They possess high thermal stability and are able to form an amorphous glass state. Crystallographic analyses indicate that the differences in ligand structure cause the change of ππ stacking character. The CH 2 Cl 2 solutions and thin films of these compounds display bright blue emission, and these compounds have appropriate HOMO and LUMO energy levels for carrier injection in OLEDs. By utilizing the good thermal and luminescent properties, as well as the proper frontier orbital energy levels, bright non-doped OLEDs with a simple structure have been realized. Notably, these simple devices show deep blue electroluminescence with the Commission Internationale de l'Éclairage (CIE) coordinate of ca. (0.16, 0.08), which is close to the CIE coordinate of (0.14, 0.08) for standard blue defined by the National Television System Committee. In addition, one of the devices exhibits good performance, showing brightness, current efficiency, power efficiency and external quantum efficiency up to 2692 cd m -2 , 2.50 cd A -1 , 1.81 lm W -1 and 3.63%, respectively. This study not only provides good deep-blue emitting OLED materials that are rarely achieved by using four-coordinate organoboron compounds, but also allows a deeper understanding of the structure-property relationship of 2-(2-hydroxyphenyl)imidazole-based boron complexes, which benefits the further structural design of this type of material.

Efficient Low-pH Iron Removal by a Microbial Iron Oxide Mound Ecosystem at Scalp Level Run.

Science.gov (United States)

Grettenberger, Christen L; Pearce, Alexandra R; Bibby, Kyle J; Jones, Daniel S; Burgos, William D; Macalady, Jennifer L

2017-04-01

Acid mine drainage (AMD) is a major environmental problem affecting tens of thousands of kilometers of waterways worldwide. Passive bioremediation of AMD relies on microbial communities to oxidize and remove iron from the system; however, iron oxidation rates in AMD environments are highly variable among sites. At Scalp Level Run (Cambria County, PA), first-order iron oxidation rates are 10 times greater than at other coal-associated iron mounds in the Appalachians. We examined the bacterial community at Scalp Level Run to determine whether a unique community is responsible for the rapid iron oxidation rate. Despite strong geochemical gradients, including a >10-fold change in the concentration of ferrous iron from 57.3 mg/liter at the emergence to 2.5 mg/liter at the base of the coal tailings pile, the bacterial community composition was nearly constant with distance from the spring outflow. Scalp Level Run contains many of the same taxa present in other AMD sites, but the community is dominated by two strains of Ferrovum myxofaciens , a species that is associated with high rates of Fe(II) oxidation in laboratory studies. IMPORTANCE Acid mine drainage pollutes more than 19,300 km of rivers and streams and 72,000 ha of lakes worldwide. Remediation is frequently ineffective and costly, upwards of $100 billion globally and nearly $5 billion in Pennsylvania alone. Microbial Fe(II) oxidation is more efficient than abiotic Fe(II) oxidation at low pH (P. C. Singer and W. Stumm, Science 167:1121-1123, 1970, https://doi.org/10.1126/science.167.3921.1121). Therefore, AMD bioremediation could harness microbial Fe(II) oxidation to fuel more-cost-effective treatments. Advances will require a deeper understanding of the ecology of Fe(II)-oxidizing microbial communities and the factors that control their distribution and rates of Fe(II) oxidation. We investigated bacterial communities that inhabit an AMD site with rapid Fe(II) oxidation and found that they were dominated by two

An iron-57 Moessbauer spectroscopic study of titania-supported iron- and iron-iridium catalysts

International Nuclear Information System (INIS)

Berry, F.J.; Jobson, S.

1992-01-01

57 Fe Moessbauer spectroscopy shows that titania-supported iron is reduced by treatment in hydrogen at significantly lower temperatures than corresponding silica- and alumina-supported catalysts. The metallic iron formed under hydrogen at 600deg C is partially converted to carbide by treatment in carbon monoxide and hydrogen. In contrast to its alumina- and silica-supported counterparts, the remainder of the titania-supported iron is unchanged by this gaseous mixture. The 57 Fe Moessbauer spectra of EXAFS show that iron and iridium in the titania-supported iron-iridium catalysts are reduced in hydrogen at even lower temperatures and, after treatment at 600deg C, are predominantly present as the iron-iridium alloy. The treatment of these reduced catalysts in carbon monoxide and hydrogen is shown by Moessbauer spectroscopy and EXAFS to induce the segregation of iron from the iron-iridium alloy and its conversion to iron oxide. (orig.)

Individual differences influence two-digit number processing, but not their analog magnitude processing: a large-scale online study.

Science.gov (United States)

Huber, Stefan; Nuerk, Hans-Christoph; Reips, Ulf-Dietrich; Soltanlou, Mojtaba

2017-12-23

Symbolic magnitude comparison is one of the most well-studied cognitive processes in research on numerical cognition. However, while the cognitive mechanisms of symbolic magnitude processing have been intensively studied, previous studies have paid less attention to individual differences influencing symbolic magnitude comparison. Employing a two-digit number comparison task in an online setting, we replicated previous effects, including the distance effect, the unit-decade compatibility effect, and the effect of cognitive control on the adaptation to filler items, in a large-scale study in 452 adults. Additionally, we observed that the most influential individual differences were participants' first language, time spent playing computer games and gender, followed by reported alcohol consumption, age and mathematical ability. Participants who used a first language with a left-to-right reading/writing direction were faster than those who read and wrote in the right-to-left direction. Reported playing time for computer games was correlated with faster reaction times. Female participants showed slower reaction times and a larger unit-decade compatibility effect than male participants. Participants who reported never consuming alcohol showed overall slower response times than others. Older participants were slower, but more accurate. Finally, higher grades in mathematics were associated with faster reaction times. We conclude that typical experiments on numerical cognition that employ a keyboard as an input device can also be run in an online setting. Moreover, while individual differences have no influence on domain-specific magnitude processing-apart from age, which increases the decade distance effect-they generally influence performance on a two-digit number comparison task.

Distance protection of multiple-circuit shared tower transmission lines with different voltages

DEFF Research Database (Denmark)

Silva, Filipe Miguel Faria da; Bak, Claus Leth

2017-01-01

Multiple-circuit transmission lines combining different voltage levels in one tower present extra challenges when setting a protection philosophy, as faults between voltage levels are possible. This study presents a detailed theoretical analysis of such combined faults, including the development...... of a formula for estimating the magnitude of the short-circuit current. It is demonstrated that if the faulted phase from the higher voltage level leads the faulted phase from the lower voltage level, a distance relay at the higher voltage level sees the fault in the forward direction, whereas a distance relay...

Moment Magnitudes and Local Magnitudes for Small Earthquakes: Implications for Ground-Motion Prediction and b-values

Science.gov (United States)

Baltay, A.; Hanks, T. C.; Vernon, F.

2016-12-01

We illustrate two essential consequences of the systematic difference between moment magnitude and local magnitude for small earthquakes, illuminating the underlying earthquake physics. Moment magnitude, M 2/3 log M0, is uniformly valid for all earthquake sizes [Hanks and Kanamori, 1979]. However, the relationship between local magnitude ML and moment is itself magnitude dependent. For moderate events, 3> fmax. Just as importantly, if this relation is overlooked, prediction of large-magnitude ground motion from small earthquakes will be misguided. We also consider the effect of this magnitude scale difference on b-value. The oft-cited b-value of 1 should hold for small magnitudes, given M. Use of ML necessitates b=2/3 for the same data set; use of mixed, or unknown, magnitudes complicates the matter further. This is of particular import when estimating the rate of large earthquakes when one has limited data on their recurrence, as is the case for induced earthquakes in the central US.

FEASIBILITY OF MEASURING IRON IN VIVO USING FAST 14 MEV NEUTRONS.

Energy Technology Data Exchange (ETDEWEB)

WIELOPOLSKI, L.

2005-05-01

In this short report, I reassess the feasibility of measuring iron in vivo in the liver and heart of thalassemia patients undergoing chelation therapy. Despite the multiplicity of analytical methods for analyzing iron, only two, magnetic resonance imaging, and magnetic susceptibility, are suitable for in vivo applications, and these are limited to the liver because of the heart's beat. Previously, a nuclear method, gamma-resonance scattering, offered a quantitative measure of iron in these organs; however, it was abandoned because it necessitated a nuclear reactor to produce the radioactive source. I reviewed and reassessed the status of two alternative nuclear methods, based on iron spectroscopy of gamma rays induced by fast neutron inelastic scattering and delayed activation in iron. Both are quantitative methods with high specificity for iron and adequate penetrating power to measure it in organs sited deep within the human body. My experiments demonstrated that both modalities met the stated qualitative objectives to measure iron. However, neutron dosimetry revealed that the intensity of the neutron radiation field was too weak to reliably assess the minimum detection limits, and to allow quantitative extrapolations to measurements in people. A review of the literature, included in this report, showed that these findings agree qualitatively with the published results, although the doses reported were about three orders-of-magnitude higher than those I used. Reviewing the limitations of the present work, steps were outlined for overcoming some of the shortcomings. Due to a dearth of valid quantitative alternatives for determining iron in vivo, I conclude that nuclear methods remain the only viable option. However, from the lessons learned, further systematic work is required before embarking on clinical studies.

Right idea, wrong magnitude system.

Science.gov (United States)

Lourenco, Stella F; Aulet, Lauren S; Ayzenberg, Vladislav; Cheung, Chi-Ngai; Holmes, Kevin J

2017-01-01

Leibovich et al. claim that number representations are non-existent early in life and that the associations between number and continuous magnitudes reside in stimulus confounds. We challenge both claims - positing, instead, that number is represented independently of continuous magnitudes already in infancy, but is nonetheless more deeply connected to other magnitudes through adulthood than acknowledged by the "sense of magnitude" theory.

Diffusion Coefficient in the Zinc Coating Shaped on the Surface of Cast Iron and Steel Alloys

Directory of Open Access Journals (Sweden)

Kopyciński D.

2015-06-01

Full Text Available The article presents the method to assess the diffusion coefficient D in the sub-layer of intermetallic phases formed during hot-dip galvanizing “Armco” iron and ductile cast iron EN-GJS-500-7. Hot-dip galvanizing is one of the most popular forms of long-term protection of Fe-C alloys against corrosion. The process for producing a protective layer of sufficient quality is closely related to diffusion of atoms of zinc and iron. The simulation consist in performed a hot-dip galvanizing in laboratory condition above Fe-C alloys, in the Department of Engineering of Cast Alloys and Composites. Galvanizing time ranged from 15 to 300 seconds. Then metallographic specimens were prepared, intermetallic layers were measured and diffusion coefficient (D were calculated. It was found that the diffusion coefficient obtained during hot-dip galvanizing “Armco” iron and zinc is about two orders of magnitude less than the coefficient obtained on ductile cast iron EN-GJS-500-7.

Historical revision of the exposure magnitude and the dosimetric magnitudes used in radiological protection; Revision historica de la magnitud exposicion y las magnitudes dosimetricas empleadas en proteccion radiologica

Energy Technology Data Exchange (ETDEWEB)

Gonzalez J, F. [UNAM, Facultad de Ciencias, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Alvarez R, J. T., E-mail: trinidad.alvarez@inin.gob.mx [ININ, Departamento de Metrologia de Radiaciones Ionizantes, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

2014-10-15

In this work a historical revision of the exposure magnitude development and their roentgen unit (1905 - 2011) is made, noting that it had their origin in the electric methods for the detection of the ionizing radiation in the period of 1895 at 1937. However, the ionization is not who better characterizes the physical, chemical and biological effects of the ionizing radiations, but is the energy deposited by this radiation in the interest bodies, which led historically to the development of dosimetric magnitudes in energy terms like they are: the absorbed dose D (1950), the kerma K (1958) and the equivalent dose H (1962). These dosimetric magnitudes culminated with the definition of the effective equivalent dose or effective dose which is not measurable and should be considered with the operative magnitudes ICRU: H environmental equivalent dose and/or H directional equivalent dose, which can be determined by means of a conversion coefficient that is applied to the exposure, kerma in air, fluence, etc. (Author)

A new class of analogues of the bifunctional radiosensitizer alpha-(1-aziridinylmethyl)-2-nitro-1H-imidazole-1-ethanol (RSU 1069): The cycloalkylaziridines

International Nuclear Information System (INIS)

Suto, M.J.; Stier, M.A.; Werbel, L.M.; Arundel-Suto, C.M.; Leopold, W.R.; Elliott, W.E.; Sebolt-Leopold, J.S.

1991-01-01

A series of compounds related to alpha-(1-aziridinylmethyl)-2-nitro-1H-imidazole-1-ethanol (RSU 1069, 1) were synthesized and evaluated as selective hypoxic cell cytotoxic agents and as radiosensitizers. The aziridine moiety was replaced with a number of other potential alkylating groups including cycloalkylaziridines and azetidines. The data indicated that modification of the aziridine of 1 resulted in a substantial decrease in the ability of the compounds to selectively kill hypoxic cells. However, these modifications did not affect the compounds' in vitro radiosensitizing activity since many of the derivatives were as potent as 1. All of the compounds that were evaluated in vivo were less toxic than 1, and several members of this series had significant activity. The best compound was trans-alpha-[[(4-bromotetrahydro-2H-pyran-3-yl) amino]methyl]-2-nitro-1H-imidazole-1-ethanol (18), which, due to its activity and log P value, is a candidate for additional in vivo studies

Absolute Nuv magnitudes of Gaia DR1 astrometric stars and a search for hot companions in nearby systems

Science.gov (United States)

Makarov, V. V.

2017-10-01

Accurate parallaxes from Gaia DR1 (TGAS) are combined with GALEX visual Nuv magnitudes to produce absolute Mnuv magnitudes and an ultraviolet HR diagram for a large sample of astrometric stars. A functional fit is derived of the lower envelope main sequence of the nearest 1403 stars (distance Pleiades, or, most likely, tight interacting binaries of the BY Dra-type. A separate collection of 40 stars with precise trigonometric parallaxes and Nuv-G colors bluer than 2 mag is presented. It includes several known novae, white dwarfs, and binaries with hot subdwarf (sdOB) components, but most remain unexplored.

Zeolitic Imidazolate Framework-8 (ZIF-8) Membranes for Kr/Xe Separation

Energy Technology Data Exchange (ETDEWEB)

Wu, Ting; Feng, Xuhui; Elsaidi, Sameh K.; Thallapally, Praveen K.; Carreon, Moises A.

2017-01-30

Herein, we demonstrate that a prototypical type of metal organic framework, zeolitic imidazolate framework-8 (ZIF-8), in membrane form, can effectively separate Kr/Xe gas mixtures at industrially relevant compositions. The best membranes separated Kr/Xe mixtures with average Kr permeances as high as 1.5 × 10^-8 ± 0.2 mol/m² s Pa and average separation selectivities of 14.2 ± 1.9 for molar feed compositions corresponding to Kr/Xe ratio encountered typically in air. Molecular sieving, competitive adsorption, and differences in diffusivities were identified as the prevailing separation mechanisms. These membranes potentially represent a less-energy-intensive alternative to cryogenic distillation, which is the benchmark technology used to separate this challenging gas mixture. To our best knowledge, this is the first example of any metal organic membrane composition displaying separation ability for Kr/Xe gas mixtures.

Presence, distribution, and diversity of iron-oxidizing bacteria at a landfill leachate-impacted groundwater surface water interface

DEFF Research Database (Denmark)

Yu, R.; Gan, P.; Mackay, A.A.

2010-01-01

) were dominated by members of the Bradyrhizobiaceae and Comamonadaceae; clones from the deeper sediments were phylogenetically more diverse, dominated by members of the Rhodocyclaceae. The iron deposition profiles indicated that active iron oxidation occurred only within the near-to-surface GSI......We examined the presence of iron-oxidizing bacteria (IOB) at a groundwater surface water interface (GSI) impacted by reduced groundwater originating as leachate from an upgradient landfill. IOB enrichments and quantifications were obtained, at high vertical resolution, by an iron/oxygen opposing...... site mirrored the IOB distribution. Clone libraries from two separate IOB enrichments indicated a stratified IOB community with clear differences at short vertical distances. Alpha- and Betaproteobacteria were the dominant phylotypes. Clones from the near-surface sediment (1-2 cm below ground surface...

X-ray absorption spectroscopic studies of the dinuclear iron center in methane monooxygenase and the sulfure and chlorine centers in photographic materials

Energy Technology Data Exchange (ETDEWEB)

DeWitt, J.G.

1992-12-01

The dinuclear iron center of the hydroxylase component of soluble methane monooxygenase (MMO) from Methylococcus capsulatus and Methylosinus trichosporiwn has been studied by X-ray absorption spectroscopy. Analysis of the Fe K-edge EXAFS revealed that the first shell coordination of the Fe(HI)Fe(IH) oxidized state of the hydroxylase from M. capsulatus consists of approximately 6 N and 0 atoms at an average distance of 2.04 [Angstrom]. The Fe-Fe distance was determined to be 3.4 [Angstrom]. No evidence for the presence of a short oxo bridge in the iron center of the oxidized hydroxylase was found, suggesting that the active site of MMO is significantly different from the active sites of the dinuclear iron proteins hemery and ribonucleotide reductase. In addition, the results of the first shell fits suggest that there are more oxygen than nitrogen donor ligands.

X-ray absorption spectroscopic studies of the dinuclear iron center in methane monooxygenase and the sulfure and chlorine centers in photographic materials

Energy Technology Data Exchange (ETDEWEB)

DeWitt, Jane G. [Stanford Univ., CA (United States)

1992-12-01

The dinuclear iron center of the hydroxylase component of soluble methane monooxygenase (MMO) from Methylococcus capsulatus and Methylosinus trichosporiwn has been studied by X-ray absorption spectroscopy. Analysis of the Fe K-edge EXAFS revealed that the first shell coordination of the Fe(HI)Fe(IH) oxidized state of the hydroxylase from M. capsulatus consists of approximately 6 N and 0 atoms at an average distance of 2.04 Å. The Fe-Fe distance was determined to be 3.4 Å. No evidence for the presence of a short oxo bridge in the iron center of the oxidized hydroxylase was found, suggesting that the active site of MMO is significantly different from the active sites of the dinuclear iron proteins hemery and ribonucleotide reductase. In addition, the results of the first shell fits suggest that there are more oxygen than nitrogen donor ligands.

The moment magnitude Mw and the energy magnitude Me: common roots and differences

OpenAIRE

2010-01-01

Abstract Starting from the classical empirical magnitude-energy relationships, in this article, the derivation of the modern scales for moment magnitude Mw and energy magnitude Me is outlined and critically discussed. The formulas for Mw and Me calculation are presented in a way that reveals, besides the contributions of the physically defined measurement parameters seismic moment M0 and radiated seismic energy ES, the role of the constants in the classical Gutenberg?Richter magnit...

Mrg: A Magnitude Scale for 1 s Rayleigh Waves at Local Distances with Focus on Yield Estimation

Science.gov (United States)

2016-08-23

definition for filtering Rg near 1 s period at distances between 2-100 km. We used the new formula to estimate MRg for 39 small (37 ≤ Y ≤ 12,270 kg TNT...the Butterworth filter order (Russell, 2006). Filter Definition . To estimate the time-domain amplitude of Rg, we filter the time series with a 2nd... phenomenology experiments, including the Arizona Source Phenomenology Experiment (AZ-SPE), Bighorn Active Seismic Experiment (BASE), the HUMMING ALBATROS

Novel fluorescent pH sensor based on coumarin with piperazine and imidazole substituents.

Science.gov (United States)

Saleh, Na'il; Al-Soud, Yaseen A; Nau, Werner M

2008-12-01

A new coumarin derivative containing piperazine and imidazole moieties is reported as a fluorophore for hydrogen ions sensing. The fluorescence enhancement of the studied sensor with an increase in hydrogen ions concentration is based on the hindering of photoinduced electron transfer from the piperazinyl amine and the imidazolyl amine to the coumarin fluorophore by protonation. The presented sensor has a novel design of fluorophore-spacer-receptor(1)-receptor(2) format, which is proposed to sense two ranges of pH (from 2.5 to 5.5) and (from 10 to 12) instead of sensing one pH range. A model compound, in which the piperazinyl ring is absent, was synthesized as well to confirm the novel pH sensing of the proposed sensor.

Carbon dioxide selective adsorption within a highly stable mixed-ligand Zeolitic Imidazolate Framework

KAUST Repository

Huang, Lin

2014-08-01

A new mixed-ligand Zeolitic Imidazolate Framework Zn4(2-mbIm) 3(bIm)5·4H2O (named JUC-160, 2-mbIm = 2-methylbenzimidazole, bIm = benzimidazole and JUC = Jilin University China) was synthesized with a solvothermal reaction of Zn(NO3) 2·6H2O, bIm and 2-mbIm in DMF solution at 180 °C. Topological analysis indicated that JUC-160 has a zeolite GIS (gismondine) topology. Study of the gas adsorption and thermal and chemical stability of JUC-160 demonstrated its selective adsorption property for carbon dioxide, high thermal stability, and remarkable chemical resistance to boiling alkaline water and organic solvent for up to one week. © 2014 Elsevier B.V.

Design, Synthesis, Antibacterial and Antifungal Activity of Novel 2-[(E-2-aryl-1-ethenyl]-3-(2-sulfanyl-1H-benzo[d]imidazole-5-yl-3,4- dihydro-4-quinolinones

Directory of Open Access Journals (Sweden)

Anisetti Ravinder Nath

2012-01-01

Full Text Available The novel 2-[(E-2-aryl-1-ethenyl]-3-(2-sulfanyl-1H-benzo[d]imidazole-5-yl-3,4- dihydro-4-quinolinones (4a-j analogs were synthesized by Knoevenagel condensation of a solution of 2-methyl-3-(2-sulfanyl-1H-benzo[d]imidazole-5-yl-3,4-dihydro-4-quinazolinone (3 with aromatic aldehyde in presence of catalytic amount of piperidine. Compounds (4a-j showed significant biological activity against all the standard strains. All the synthesized compounds were characterized on the basis of their IR, 1H NMR, MASS spectroscopic data and elemental analyses. All the compounds have been tested for antimicrobial and antifungal activity by the cup-plate method.

Higher iron bioavailability of a human-like collagen iron complex.

Science.gov (United States)

Zhu, Chenhui; Yang, Fan; Fan, Daidi; Wang, Ya; Yu, Yuanyuan

2017-07-01

Iron deficiency remains a public health problem around the world due to low iron intake and/or bioavailability. FeSO 4 , ferrous succinate, and ferrous glycinate chelate are rich in iron but have poor bioavailability. To solve the problem of iron deficiency, following previous research studies, a thiolated human-like collagen-ironcomplex supplement with a high iron content was prepared in an anaerobic workstation. In addition, cell viability tests were evaluated after conducting an MTT assay, and a quantitative analysis of the thiolated human-like collagen-iron digesta samples was performed using the SDS-PAGE method coupled with gel filtration chromatography. The iron bioavailability was assessed using Caco-2 cell monolayers and iron-deficiency anemia mice models. The results showed that (1) one mole of thiolated human-like collagen-iron possessed approximately 35.34 moles of iron; (2) thiolated human-like collagen-iron did not exhibit cytotoxity and (3) thiolated human-like collagen- iron digesta samples had higher bioavailability than other iron supplements, including FeSO 4 , ferrous succinate, ferrous glycine chelate and thiolated human-like collagen-Fe iron. Finally, the iron bioavailability was significantly enhanced by vitamin C. These results indicated that thiolated human-like collagen-iron is a promising iron supplement for use in the future.

Zeolitic imidazolate framework membranes and methods of making and using same for separation of c2- and c3+ hydrocarbons and separation of propylene and propane mixtures

KAUST Repository

Lai, Zhiping

2012-12-06

Certain embodiments are directed to processes for fabrication of zeolitic imidazolate framework (ZIF) membranes. These ZIF membranes can be used in separating C2-hydrocarbons from C3+ hydrocarbons and propylene/propane mixtures.

Zeolitic imidazolate framework membranes and methods of making and using same for separation of c2- and c3+ hydrocarbons and separation of propylene and propane mixtures

KAUST Repository

Lai, Zhiping; Pan, Yichang

2012-01-01

Certain embodiments are directed to processes for fabrication of zeolitic imidazolate framework (ZIF) membranes. These ZIF membranes can be used in separating C2-hydrocarbons from C3+ hydrocarbons and propylene/propane mixtures.

Catalytic constructive deoxygenation of lignin-derived phenols: new C-C bond formation processes from imidazole-sulfonates and ether cleavage reactions.

Science.gov (United States)

Leckie, Stuart M; Harkness, Gavin J; Clarke, Matthew L

2014-10-09

As part of a programme aimed at exploiting lignin as a chemical feedstock for less oxygenated fine chemicals, several catalytic C-C bond forming reactions utilising guaiacol imidazole sulfonate are demonstrated. These include the cross-coupling of a Grignard, a non-toxic cyanide source, a benzoxazole, and nitromethane. A modified Meyers reaction is used to accomplish a second constructive deoxygenation on a benzoxazole functionalised anisole.

Impact of the natural Fe-fertilization on the magnitude, stoichiometry and efficiency of particulate biogenic silica, nitrogen and iron export fluxes

Science.gov (United States)

Lemaitre, N.; Planquette, H.; Dehairs, F.; van der Merwe, P.; Bowie, A. R.; Trull, T. W.; Laurenceau-Cornec, E. C.; Davies, D.; Bollinger, C.; Le Goff, M.; Grossteffan, E.; Planchon, F.

2016-11-01

The Kerguelen Plateau is characterized by a naturally Fe-fertilized phytoplankton bloom that extends more than 1000 km downstream in the Antarctic Circumpolar Current. During the KEOPS2 study, in austral spring, we measured particulate nitrogen (PN), biogenic silica (BSi) and particulate iron (PFe) export fluxes in order to investigate how the natural fertilization impacts the stoichiometry and the magnitude of export fluxes and therefore the efficiency of the biological carbon pump. At 9 stations, we estimated elemental export fluxes based on element concentration to 234Th activity ratios for particulate material collected with in-situ pumps and 234Th export fluxes (Planchon et al., 2015). This study revealed that the natural Fe-fertilization increased export fluxes but to variable degrees. Export fluxes for the bloom impacted area were compared with those of a high-nutrient, low-chlorophyll (HNLC), low-productive reference site located to the south-west of Kerguelen and which had the lowest BSi and PFe export fluxes (2.55 mmol BSi m-2 d-1 and 1.92 μmol PFem-2 d-1) and amongst the lowest PN export flux (0.73 mmol PN m-2 d-1). The impact of the Fe fertilization was the greatest within a meander of the polar front (PF), to the east of Kerguelen, with fluxes reaching 1.26 mmol PN m-2 d-1; 20.4 mmol BSi m-2 d-1 and 22.4 μmol PFe m-2 d-1. A highly productive site above the Kerguelen Plateau, on the contrary, was less impacted by the fertilization with export fluxes reaching 0.72 mmol PN m-2 d-1; 4.50 mmol BSi m-2 d-1 and 21.4 μmol PFe m-2 d-1. Our results suggest that ecosystem features (i.e. type of diatom community) could play an important role in setting the magnitude of export fluxes of these elements. Indeed, for the PF meander, the moderate productivity was sustained by the presence of large and strongly silicified diatom species while at the higher productivity sites, smaller and slightly silicified diatoms dominated. Interestingly, our results suggest that

THE IMPACT OF CONTAMINATED RR LYRAE/GLOBULAR CLUSTER PHOTOMETRY ON THE DISTANCE SCALE

Energy Technology Data Exchange (ETDEWEB)

Majaess, D.; Turner, D.; Lane, D. [Department of Astronomy and Physics, Saint Mary' s University, Halifax, NS B3H 3C3 (Canada); Gieren, W., E-mail: dmajaess@ap.smu.ca [Departamento de Astronomia, Universidad de Concepcion, Casilla 160-C, CL Concepcion (Chile)

2012-06-10

RR Lyrae variables and the stellar constituents of globular clusters are employed to establish the cosmic distance scale and age of the universe. However, photometry for RR Lyrae variables in the globular clusters M3, M15, M54, M92, NGC 2419, and NGC 6441 exhibit a dependence on the clustercentric distance. For example, variables and stars positioned near the crowded high-surface brightness cores of the clusters may suffer from photometric contamination, which invariably affects a suite of inferred parameters (e.g., distance, color excess, absolute magnitude, etc.). The impetus for this study is to mitigate the propagation of systematic uncertainties by increasing awareness of the pernicious impact of contaminated and radial-dependent photometry.

Aerogel Antennas Communications Study Using Error Vector Magnitude Measurements

Science.gov (United States)

Miranda, Felix A.; Mueller, Carl H.; Meador, Mary Ann B.

2014-01-01

This presentation discusses an aerogel antennas communication study using error vector magnitude (EVM) measurements. The study was performed using 2x4 element polyimide (PI) aerogel-based phased arrays designed for operation at 5 GHz as transmit (Tx) and receive (Rx) antennas separated by a line of sight (LOS) distance of 8.5 meters. The results of the EVM measurements demonstrate that polyimide aerogel antennas work appropriately to support digital communication links with typically used modulation schemes such as QPSK and 4 DQPSK. As such, PI aerogel antennas with higher gain, larger bandwidth and lower mass than typically used microwave laminates could be suitable to enable aerospace-to- ground communication links with enough channel capacity to support voice, data and video links from CubeSats, unmanned air vehicles (UAV), and commercial aircraft.

Aerogel Antennas Communications Study Using Error Vector Magnitude Measurements

Science.gov (United States)

Miranda, Felix A.; Mueller, Carl H.; Meador, Mary Ann B.

2014-01-01

This paper discusses an aerogel antennas communication study using error vector magnitude (EVM) measurements. The study was performed using 4x2 element polyimide (PI) aerogel-based phased arrays designed for operation at 5 GHz as transmit (Tx) and receive (Rx) antennas separated by a line of sight (LOS) distance of 8.5 meters. The results of the EVM measurements demonstrate that polyimide aerogel antennas work appropriately to support digital communication links with typically used modulation schemes such as QPSK and pi/4 DQPSK. As such, PI aerogel antennas with higher gain, larger bandwidth and lower mass than typically used microwave laminates could be suitable to enable aerospace-to-ground communication links with enough channel capacity to support voice, data and video links from cubesats, unmanned air vehicles (UAV), and commercial aircraft.

Moment magnitude scale

Energy Technology Data Exchange (ETDEWEB)

Hanks, T.C.; Kanamori, H.

1979-05-10

The nearly conincident forms of the relations between seismic moment M/sub o/ and the magnitudes M/sub L/, M/sub s/, and M/sub w/ imply a moment magnitude scale M=2/3 log M/sub o/-10.7 which is uniformly valid for 3< or approx. =M/sub L/< or approx. = 7, 5 < or approx. =M/sub s/< or approx. =7 1/2 and M/sub w/> or approx. = 7 1/2.

Novel decavanadate cluster complexes [H2V10O28][LH]4·nH2O (L = Imidazole, n = 2 or 2-methylimidazole, n = 0): Preparation, characterization and genotoxic studies

Science.gov (United States)

Siddiqi, Zafar A.; Anjuli; Sharma, Prashant K.; Shahid, M.; Khalid, Mohd.; Siddique, Armeen; Kumar, Sarvendra

2012-12-01

The title complexes were obtained from the reaction of VOSO4 with imidazole or 2-methyl imidazole in presence of adipic acid/iminodiacetic acid. X-ray crystallographic investigations on [H2V10O28](2-MeImzH)4 (2) revealed a strong interaction between decavanadate anion and the protonated ligand moieties as counter cations to stabilize the crystal motif resulting in a high symmetry 2D sheet network. The cyclic voltammetry of (2) suggested formation of a quasi-reversible redox (VV/IV) couple in the solution. The genotoxic studies employing single cell gel electrophoresis (comet assay) confirmed the non-toxic nature of the compounds.

Iron

Science.gov (United States)

Iron is a mineral that our bodies need for many functions. For example, iron is part of hemoglobin, a protein which carries ... It helps our muscles store and use oxygen. Iron is also part of many other proteins and ...

A cascade of iron-containing proteins governs the genetic iron starvation response to promote iron uptake and inhibit iron storage in fission yeast.

Directory of Open Access Journals (Sweden)

Javier Encinar del Dedo

2015-03-01

Full Text Available Iron is an essential cofactor, but it is also toxic at high levels. In Schizosaccharomyces pombe, the sensor glutaredoxin Grx4 guides the activity of the repressors Php4 and Fep1 to mediate a complex transcriptional response to iron deprivation: activation of Php4 and inactivation of Fep1 leads to inhibition of iron usage/storage, and to promotion of iron import, respectively. However, the molecular events ruling the activity of this double-branched pathway remained elusive. We show here that Grx4 incorporates a glutathione-containing iron-sulfur cluster, alone or forming a heterodimer with the BolA-like protein Fra2. Our genetic study demonstrates that Grx4-Fra2, but not Fep1 nor Php4, participates not only in iron starvation signaling but also in iron-related aerobic metabolism. Iron-containing Grx4 binds and inactivates the Php4 repressor; upon iron deprivation, the cluster in Grx4 is probably disassembled, the proteins dissociate, and Php4 accumulates at the nucleus and represses iron consumption genes. Fep1 is also an iron-containing protein, and the tightly bound iron is required for transcriptional repression. Our data suggest that the cluster-containing Grx4-Fra2 heterodimer constitutively binds to Fep1, and upon iron deprivation the disassembly of the iron cluster between Grx4 and Fra2 promotes reverse metal transfer from Fep1 to Grx4-Fra2, and de-repression of iron-import genes. Our genetic and biochemical study demonstrates that the glutaredoxin Grx4 independently governs the Php4 and Fep1 repressors through metal transfer. Whereas iron loss from Grx4 seems to be sufficient to release Php4 and allow its nuclear accumulation, total or partial disassembly of the Grx4-Fra2 cluster actively participates in iron-containing Fep1 activation by sequestering its iron and decreasing its interaction with promoters.

Long-distance electron transfer by cable bacteria in aquifer sediments

DEFF Research Database (Denmark)

Müller, Hubert; Bosch, Julian; Griebler, Christian

2016-01-01

recycling of sulfate by electron transfer over 1–2-cm distance. Sediments were taken from a hydrocarbon-contaminated aquifer, amended with iron sulfide and saturated with water, leaving the sediment surface exposed to air. Steep geochemical gradients developed in the upper 3 cm, showing a spatial separation...... recently been discovered in marine sediments to couple spatially separated redox half reactions over centimeter scales. Here we provide primary evidence that such sulfur-oxidizing cable bacteria can also be found at oxic–anoxic interfaces in aquifer sediments, where they provide a means for the direct...

Dietary iron intake, iron status, and gestational diabetes.

Science.gov (United States)

Zhang, Cuilin; Rawal, Shristi

2017-12-01

Pregnant women are particularly vulnerable to iron deficiency and related adverse pregnancy outcomes and, as such, are routinely recommended for iron supplementation. Emerging evidence from both animal and population-based studies, however, has raised potential concerns because significant associations have been observed between greater iron stores and disturbances in glucose metabolism, including increased risk of type 2 diabetes among nonpregnant individuals. Yet, the evidence is uncertain regarding the role of iron in the development of gestational diabetes mellitus (GDM), a common pregnancy complication which has short-term and long-term adverse health ramifications for both women and their children. In this review, we critically and systematically evaluate available data examining the risk of GDM associated with dietary iron, iron supplementation, and iron status as measured by blood concentrations of several indicators. We also discuss major methodologic concerns regarding the available epidemiologic studies on iron and GDM. © 2017 American Society for Nutrition.

Studies on the pathogenesis in iron deficiency anemia Part 1. Urinary iron excretion in iron deficiency anemia patients and rats in various iron states

OpenAIRE

中西,徳彦

1991-01-01

In the "iron excretion test" , urinary iron excretion after injection of saccharated iron oxide has been reported to be accelerated in relapsing idiopathic iron deficiency anemia. To determine the relevance of urinary iron excretion to clinical factors other than iron metabolism, 15 clinical parameters were evaluated. The serum creatinine level was positively and the serum albumin level was negatively correlated with urinary iron excretion, showing coefficients of r＝0.97,－0.86 respectively, a...

Antifungal activity of tioconazole (UK-20,349), a new imidazole derivative.

Science.gov (United States)

Jevons, S; Gymer, G E; Brammer, K W; Cox, D A; Leeming, M R

1979-04-01

Tioconazole (UK-20,349), a new antifungal imidazole derivative, was compared with miconazole for activity in vitro against Candida spp., Torulopsis glabrata, Cryptococcus neoformans, Aspergillus spp., and dermatophyte fungi (Trichophyton spp. and Microsporum spp.). Tioconazole was more active than miconazole against all the fungal species examined except Aspergillus, against which both agents showed similar activity. Both tioconazole and miconazole inhibited the growth of all fungi examined at concentrations well below their quoted minimum inhibitory concentrations. Their activity against fungi in vivo was investigated in mice infected systemically with Candida albicans. Both agents significantly reduced the numbers of viable Candida cells recoverable from the kidneys of infected animals, with tioconazole producing a generally more marked reduction. After administration of a single oral dose (25 mg/kg) to beagle dogs or white mice, higher and more sustained circulating levels of bioactive drug were detectable of tioconazole than of miconazole. These observations suggest that tioconazole may have potential in the treatment of both superficial and systemic mycoses in humans.

CALIBRATION OF THE MEARTH PHOTOMETRIC SYSTEM: OPTICAL MAGNITUDES AND PHOTOMETRIC METALLICITY ESTIMATES FOR 1802 NEARBY M-DWARFS

International Nuclear Information System (INIS)

Dittmann, Jason A.; Irwin, Jonathan M.; Charbonneau, David; Newton, Elisabeth R.

2016-01-01

The MEarth Project is a photometric survey systematically searching the smallest stars near the Sun for transiting rocky planets. Since 2008, MEarth has taken approximately two million images of 1844 stars suspected to be mid-to-late M dwarfs. We have augmented this survey by taking nightly exposures of photometric standard stars and have utilized this data to photometrically calibrate the MEarth system, identify photometric nights, and obtain an optical magnitude with 1.5% precision for each M dwarf system. Each optical magnitude is an average over many years of data, and therefore should be largely immune to stellar variability and flaring. We combine this with trigonometric distance measurements, spectroscopic metallicity measurements, and 2MASS infrared magnitude measurements in order to derive a color–magnitude–metallicity relation across the mid-to-late M dwarf spectral sequence that can reproduce spectroscopic metallicity determinations to a precision of 0.1 dex. We release optical magnitudes and metallicity estimates for 1567 M dwarfs, many of which did not have an accurate determination of either prior to this work. For an additional 277 stars without a trigonometric parallax, we provide an estimate of the distance, assuming solar neighborhood metallicity. We find that the median metallicity for a volume-limited sample of stars within 20 pc of the Sun is [Fe/H] = −0.03 ± 0.008, and that 29/565 of these stars have a metallicity of [Fe/H] = −0.5 or lower, similar to the low-metallicity distribution of nearby G dwarfs. When combined with the results of ongoing and future planet surveys targeting these objects, the metallicity estimates presented here will be important for assessing the significance of any putative planet–metallicity correlation

CALIBRATION OF THE MEARTH PHOTOMETRIC SYSTEM: OPTICAL MAGNITUDES AND PHOTOMETRIC METALLICITY ESTIMATES FOR 1802 NEARBY M-DWARFS

Energy Technology Data Exchange (ETDEWEB)

Dittmann, Jason A.; Irwin, Jonathan M.; Charbonneau, David; Newton, Elisabeth R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States)

2016-02-20

The MEarth Project is a photometric survey systematically searching the smallest stars near the Sun for transiting rocky planets. Since 2008, MEarth has taken approximately two million images of 1844 stars suspected to be mid-to-late M dwarfs. We have augmented this survey by taking nightly exposures of photometric standard stars and have utilized this data to photometrically calibrate the MEarth system, identify photometric nights, and obtain an optical magnitude with 1.5% precision for each M dwarf system. Each optical magnitude is an average over many years of data, and therefore should be largely immune to stellar variability and flaring. We combine this with trigonometric distance measurements, spectroscopic metallicity measurements, and 2MASS infrared magnitude measurements in order to derive a color–magnitude–metallicity relation across the mid-to-late M dwarf spectral sequence that can reproduce spectroscopic metallicity determinations to a precision of 0.1 dex. We release optical magnitudes and metallicity estimates for 1567 M dwarfs, many of which did not have an accurate determination of either prior to this work. For an additional 277 stars without a trigonometric parallax, we provide an estimate of the distance, assuming solar neighborhood metallicity. We find that the median metallicity for a volume-limited sample of stars within 20 pc of the Sun is [Fe/H] = −0.03 ± 0.008, and that 29/565 of these stars have a metallicity of [Fe/H] = −0.5 or lower, similar to the low-metallicity distribution of nearby G dwarfs. When combined with the results of ongoing and future planet surveys targeting these objects, the metallicity estimates presented here will be important for assessing the significance of any putative planet–metallicity correlation.

Conversion of Local and Surface-Wave Magnitudes to Moment Magnitude for Earthquakes in the Chinese Mainland

Science.gov (United States)

Li, X.; Gao, M.

2017-12-01

The magnitude of an earthquake is one of its basic parameters and is a measure of its scale. It plays a significant role in seismology and earthquake engineering research, particularly in the calculations of the seismic rate and b value in earthquake prediction and seismic hazard analysis. However, several current types of magnitudes used in seismology research, such as local magnitude (ML), surface wave magnitude (MS), and body-wave magnitude (MB), have a common limitation, which is the magnitude saturation phenomenon. Fortunately, the problem of magnitude saturation was solved by a formula for calculating the seismic moment magnitude (MW) based on the seismic moment, which describes the seismic source strength. Now the moment magnitude is very commonly used in seismology research. However, in China, the earthquake scale is primarily based on local and surface-wave magnitudes. In the present work, we studied the empirical relationships between moment magnitude (MW) and local magnitude (ML) as well as surface wave magnitude (MS) in the Chinese Mainland. The China Earthquake Networks Center (CENC) ML catalog, China Seismograph Network (CSN) MS catalog, ANSS Comprehensive Earthquake Catalog (ComCat), and Global Centroid Moment Tensor (GCMT) are adopted to regress the relationships using the orthogonal regression method. The obtained relationships are as follows: MW=0.64+0.87MS; MW=1.16+0.75ML. Therefore, in China, if the moment magnitude of an earthquake is not reported by any agency in the world, we can use the equations mentioned above for converting ML to MW and MS to MW. These relationships are very important, because they will allow the China earthquake catalogs to be used more effectively for seismic hazard analysis, earthquake prediction, and other seismology research. We also computed the relationships of and (where Mo is the seismic moment) by linear regression using the Global Centroid Moment Tensor. The obtained relationships are as follows: logMo=18

Moment Magnitude discussion in Austria

Science.gov (United States)

Weginger, Stefan; Jia, Yan; Hausmann, Helmut; Lenhardt, Wolfgang

2017-04-01

We implemented and tested the Moment Magnitude estimation „dbmw" from the University of Trieste in our Antelope near real-time System. It is used to get a fast Moment Magnitude solutions and Ground Motion Parameter (PGA, PGV, PSA 0.3, PSA 1.0 and PSA 3.0) to calculate Shake and Interactive maps. A Moment Magnitude Catalogue was generated and compared with the Austrian Earthquake Catalogue and all available Magnitude solution of the neighbouring agencies. Relations of Mw to Ml and Ground Motion to Intensity are presented.

Iron from Zealandic bog iron ore -

DEFF Research Database (Denmark)

Lyngstrøm, Henriette Syrach

2011-01-01

og geologiske materiale, metallurgiske analyser og eksperimentel arkæologiske forsøg - konturerne af en jernproduktion med udgangspunkt i den sjællandske myremalm. The frequent application by archaeologists of Werner Christensen’s distribution map for the occurrence of bog iron ore in Denmark (1966...... are sketched of iron production based on bog iron ore from Zealand....

Response to parenteral iron therapy distinguish unexplained refractory iron deficiency anemia from iron-refractory iron deficiency anemia.

Science.gov (United States)

Akin, M; Sarbay, H; Guler, S; Balci, Y I; Polat, A

2016-04-01

We evaluated that response to parenteral iron therapy could be helpful in distinguishing the types of iron deficiency anemia. This study analyzed responses to IV iron sucrose therapy of 15 children with unexplained refractory iron deficiency anemia (URIDA). We compared the results at diagnosis, 6 weeks and 6 months after the therapy. Results were compared with responses of 11 patients' results with iron-refractory iron deficiency anemia (IRIDA) from our previous study. Six weeks after the start of treatment, ferritin, MCV, MCH and Hb values were in normal range in 10 patients. The increase in Hb, MCH, MCV, and ferritin values ranged 2.6-3.5 g/dL, 1.7-4.2 pg, 2-9 fL, and 13-25 ng/mL, respectively. In five patients, Hb, MCH, and MCV mean (range) values [11.2 g/dL (11-12.2), 24.5 pg (24-25.6), and 67 fL (65-70)] were nearly normal but ferritin mean (range) values [9.8 ng/mL (8-11)] were below normal. Six weeks after the start of treatment, Hb, MCH, MCV and ferritin values of patients with IRIDA were increased. The increase in Hb, MCH, MCV, and ferritin values ranged 0.8-2.7 g/dL, 1.7-4.2 pg, 2-9 fL, and 13-25 ng/mL, respectively. IRIDA is only partially responsive to parenteral iron supplementation. In conclusion, this study demonstrated that the response to intravenous iron therapy for the URIDA cases improved blood parameters more effectively than hereditary IRIDA. Response to parenteral iron therapy would be helpful to distinguish unexplained refractory IDA from hereditary IRIDA for clinicians who do not have access to hepcidin or TMPRS6 mutation analysis. © 2016 John Wiley & Sons Ltd.

Moment Magnitude Calibration for the Eastern Mediterranean Region from Broadband Regional Coda Envelopes

Energy Technology Data Exchange (ETDEWEB)

Mayeda, K; Eken, T; Hofstetter, A; Turkelli, N; O' Boyle, J; Orgulu, G; Gok, R

2003-07-17

estimates for events that were too small either to be reliably waveform modeled or to be seen at far-regional and teleseismic distances. In general coda-derived magnitudes are roughly a factor of 3 to 5 more stable than traditional regional magnitudes that use the direct-phases such as P{sub g} and L{sub g}. This appears to be a universal observation for all regions where the coda methodology has been applied.

Scaling Relations of Local Magnitude versus Moment Magnitude for Sequences of Similar Earthquakes in Switzerland

KAUST Repository

Bethmann, F.

2011-03-22

Theoretical considerations and empirical regressions show that, in the magnitude range between 3 and 5, local magnitude, ML, and moment magnitude, Mw, scale 1:1. Previous studies suggest that for smaller magnitudes this 1:1 scaling breaks down. However, the scatter between ML and Mw at small magnitudes is usually large and the resulting scaling relations are therefore uncertain. In an attempt to reduce these uncertainties, we first analyze the ML versus Mw relation based on 195 events, induced by the stimulation of a geothermal reservoir below the city of Basel, Switzerland. Values of ML range from 0.7 to 3.4. From these data we derive a scaling of ML ~ 1:5Mw over the given magnitude range. We then compare peak Wood-Anderson amplitudes to the low-frequency plateau of the displacement spectra for six sequences of similar earthquakes in Switzerland in the range of 0:5 ≤ ML ≤ 4:1. Because effects due to the radiation pattern and to the propagation path between source and receiver are nearly identical at a particular station for all events in a given sequence, the scatter in the data is substantially reduced. Again we obtain a scaling equivalent to ML ~ 1:5Mw. Based on simulations using synthetic source time functions for different magnitudes and Q values estimated from spectral ratios between downhole and surface recordings, we conclude that the observed scaling can be explained by attenuation and scattering along the path. Other effects that could explain the observed magnitude scaling, such as a possible systematic increase of stress drop or rupture velocity with moment magnitude, are masked by attenuation along the path.

Iron isomaltoside 1000: a new intravenous iron for treating iron deficiency in chronic kidney disease

DEFF Research Database (Denmark)

Wikström, Björn; Bhandari, Sunil; Barany, Peter

2011-01-01

Patients with chronic kidney disease (CKD) often suffer from iron deficiency anemia necessitating treatment with intravenous iron. This study was designed to assess the safety of iron isomaltoside 1000 (Monofer) in CKD patients. The secondary objective was to assess its effect on iron deficiency...... anemia....

The Effect Of Local Coal And Smelting Sponge Iron On Iron Content Of Pig Iron

Science.gov (United States)

Oediyani, Soesaptri; Juwita Sari, Pramita; Hadi P, Djoko

2018-03-01

The new regulation on mineral resources was announced by Ministry of Energy and Mineral resources (ESDM) of Indonesia at 2014 which it called Permen ESDM No 1/2014. Therefore, this research was conducted to add the value of local iron ores by using smelting technology. The objective of the research is to produce pig iron that meet the requirement of the new regulation of mineral resources such as 90% Fe. First, iron ores and coal mixed together with lime as a flux, then smelted in a Electric Arc Furnace at 1800°C. The process variables are (1; 1.25; 1.5; 1.75; 2.0) and the composition of coal (0.8%, 1.6%, 3.0%). The type of coal that used in this research was bituminous coal from Kalimantan and also the iron ores from Kalimantan. The products of the smelting technology are Pig iron and slag. Both pig iron and slag then analyzed by SEM-EDS to measure the iron content. The result shows that the maximum iron content on pig iron is about 95.04% meanwhile the minimum iron content on slag is about 3.66%. This result achieved at 1.6% coal and 2.0.

Iron biomineralization by anaerobic neutrophilic iron-oxidizing bacteria

DEFF Research Database (Denmark)

Miot, Jennyfer; Benzerara, Karim; Morin, Guillaume

2009-01-01

Minerals formed by bio-oxidation of ferrous iron (Fe(II)) at neutral pH, their association with bacterial ultrastructures as well as their impact on the metabolism of iron-oxidizing bacteria remain poorly understood. Here, we investigated iron biomineralization by the anaerobic nitrate-dependent ......Minerals formed by bio-oxidation of ferrous iron (Fe(II)) at neutral pH, their association with bacterial ultrastructures as well as their impact on the metabolism of iron-oxidizing bacteria remain poorly understood. Here, we investigated iron biomineralization by the anaerobic nitrate...... precipitation in the periplasm (in a few tens of minutes), followed by the formation of surface-bound globules. Moreover, we frequently observed an asymmetric mineral thickening at the cell poles. In parallel, the evolution of iron oxidation was quantified by STXM: iron both contained in the bacteria...... and in the extracellular precipitates reached complete oxidation within 6 days. While a progressive oxidation of Fe in the bacteria and in the medium could be observed, spatial redox (oxido-reduction state) heterogeneities were detected at the cell poles and in the extracellular precipitates after 1 day. All...

ESTIMATION OF DISTANCES TO STARS WITH STELLAR PARAMETERS FROM LAMOST

Energy Technology Data Exchange (ETDEWEB)

Carlin, Jeffrey L.; Newberg, Heidi Jo [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Liu, Chao; Deng, Licai; Li, Guangwei; Luo, A-Li; Wu, Yue; Yang, Ming; Zhang, Haotong [Key Lab of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Beers, Timothy C. [Department of Physics and JINA: Joint Institute for Nuclear Astrophysics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Chen, Li; Hou, Jinliang; Smith, Martin C. [Shanghai Astronomical Observatory, 80 Nandan Road, Shanghai 200030 (China); Guhathakurta, Puragra [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Hou, Yonghui [Nanjing Institute of Astronomical Optics and Technology, National Astronomical Observatories, Chinese Academy of Sciences, Nanjing 210042 (China); Lépine, Sébastien [Department of Physics and Astronomy, Georgia State University, 25 Park Place, Suite 605, Atlanta, GA 30303 (United States); Yanny, Brian [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Zheng, Zheng, E-mail: jeffreylcarlin@gmail.com [Department of Physics and Astronomy, University of Utah, UT 84112 (United States)

2015-07-15

We present a method to estimate distances to stars with spectroscopically derived stellar parameters. The technique is a Bayesian approach with likelihood estimated via comparison of measured parameters to a grid of stellar isochrones, and returns a posterior probability density function for each star’s absolute magnitude. This technique is tailored specifically to data from the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) survey. Because LAMOST obtains roughly 3000 stellar spectra simultaneously within each ∼5° diameter “plate” that is observed, we can use the stellar parameters of the observed stars to account for the stellar luminosity function and target selection effects. This removes biasing assumptions about the underlying populations, both due to predictions of the luminosity function from stellar evolution modeling, and from Galactic models of stellar populations along each line of sight. Using calibration data of stars with known distances and stellar parameters, we show that our method recovers distances for most stars within ∼20%, but with some systematic overestimation of distances to halo giants. We apply our code to the LAMOST database, and show that the current precision of LAMOST stellar parameters permits measurements of distances with ∼40% error bars. This precision should improve as the LAMOST data pipelines continue to be refined.

Nanoscale structure and atomic disorder in the iron-based chalcogenides

Directory of Open Access Journals (Sweden)

Naurang Lal Saini

2013-01-01

Full Text Available The multiband iron-based superconductors have layered structure with a phase diagram characterized by a complex interplay of charge, spin and lattice excitations, with nanoscale atomic structure playing a key role in their fundamental electronic properties. In this paper, we briefly review nanoscale structure and atomic disorder in iron-based chalcogenide superconductors. We focus on the Fe(Se,S1−xTex (11-type and K0.8Fe1.6Se2 (122-type systems, discussing their local structure obtained by extended x-ray absorption fine structure. Local structure studies on the Fe(Se,S1−xTex system reveal clear nanoscale phase separation characterized by coexisting components of different atomic configurations, similar to the case of random alloys. In fact, the Fe–Se/S and Fe–Te distances in the ternary Fe(Se,S1−xTex are found to be closer to the respective distances in the binary FeSe/FeS and FeTe systems, showing significant divergence of the local structure from the average one. The observed features are characteristic of ternary random alloys, indicating breaking of the local symmetry in these materials. On the other hand, K0.8Fe1.6Se2 is known for phase separation in an iron-vacancy ordered phase and an in-plane compressed lattice phase. The local structure of these 122-type chalcogenides shows that this system is characterized by a large local disorder. Indeed, the experiments suggest a nanoscale glassy phase in K0.8Fe1.6Se2, with the superconductivity being similar to the granular materials. While the 11-type structure has no spacer layer, the 122-type structure contains intercalated atoms unlike the 1111-type REFeAsO (RE = rare earth oxypnictides, having well-defined REO spacer layers. It is clear that the interlayer atomic correlations in these iron-based superconducting structures play an important role in structural stability as well as superconductivity and magnetism.

46 CFR 56.60-10 - Cast iron and malleable iron.

Science.gov (United States)

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Cast iron and malleable iron. 56.60-10 Section 56.60-10... APPURTENANCES Materials § 56.60-10 Cast iron and malleable iron. (a) The low ductility of cast iron and malleable iron should be recognized and the use of these metals where shock loading may occur should be...

The efficacy of support vector machines (SVM) in robust determination of earthquake early warning magnitudes in central Japan

Science.gov (United States)

Reddy, Ramakrushna; Nair, Rajesh R.

2013-10-01

This work deals with a methodology applied to seismic early warning systems which are designed to provide real-time estimation of the magnitude of an event. We will reappraise the work of Simons et al. (2006), who on the basis of wavelet approach predicted a magnitude error of ±1. We will verify and improve upon the methodology of Simons et al. (2006) by applying an SVM statistical learning machine on the time-scale wavelet decomposition methods. We used the data of 108 events in central Japan with magnitude ranging from 3 to 7.4 recorded at KiK-net network stations, for a source-receiver distance of up to 150 km during the period 1998-2011. We applied a wavelet transform on the seismogram data and calculating scale-dependent threshold wavelet coefficients. These coefficients were then classified into low magnitude and high magnitude events by constructing a maximum margin hyperplane between the two classes, which forms the essence of SVMs. Further, the classified events from both the classes were picked up and linear regressions were plotted to determine the relationship between wavelet coefficient magnitude and earthquake magnitude, which in turn helped us to estimate the earthquake magnitude of an event given its threshold wavelet coefficient. At wavelet scale number 7, we predicted the earthquake magnitude of an event within 2.7 seconds. This means that a magnitude determination is available within 2.7 s after the initial onset of the P-wave. These results shed light on the application of SVM as a way to choose the optimal regression function to estimate the magnitude from a few seconds of an incoming seismogram. This would improve the approaches from Simons et al. (2006) which use an average of the two regression functions to estimate the magnitude.

Statistical parallaxes and the fundamental distance scale

International Nuclear Information System (INIS)

Clube, S.V.M.; Dawe, J.A.

1980-01-01

The statistical parallax technique of Paper I is used to derive an absolute magnitude of = 1.0 +- 0.25 mag for the set of 59 high ΔS RR Lyrae stars of Clube and Jones. Taken in conjunction with the kinematical properties of RR Lyrae variables and other field stars, this magnitude leads to the following values for the principal galactic constants: R 0 = approximately 7 +- 1 kpc, A = approximately 16 +- 3 km s -1 kpc -1 , B = approximately -20 +- 5 km s -1 kpc -1 and theta 0 = approximately 250 +- 40 km s -1 . The technique is also applied to Wielen's set of 45 Cepheids and no correction of the galactic Cepheid distance scale based on cluster members is found to be necessary. These sets of results are consistent if, as has been shown elsewhere, the kinematic model used to analyse the motions of young stars takes account of radial motions in the Galaxy. The distances to the Magellanic Clouds given by RR Lyraes and Cepheids are in conflict however. Although the evidence suggesting a general similarity of halo RR Lyraes in our Galaxy and the Magellanic Clouds is not absolutely conclusive, it is suggested that the conflict may be resolved by use of a colour term in the P-L-C relation for Cepheids which is much less than that adopted by Sandage and Tammann. The conclusions are in general accord with recent proposals seeking to increase the Hubble constant to around 80 km s -1 Mpc -1 . (author)

A tailored biocatalyst achieved by the rational anchoring of imidazole groups on a natural polymer: furnishing a potential artificial nuclease by sustainable materials engineering.

Science.gov (United States)

Ferreira, José G L; Grein-Iankovski, Aline; Oliveira, Marco A S; Simas-Tosin, Fernanda F; Riegel-Vidotti, Izabel C; Orth, Elisa S

2015-04-11

Foreseeing the development of artificial enzymes by sustainable materials engineering, we rationally anchored reactive imidazole groups on gum arabic, a natural biocompatible polymer. The tailored biocatalyst GAIMZ demonstrated catalytic activity (>10(5)-fold) in dephosphorylation reactions with recyclable features and was effective in cleaving plasmid DNA, comprising a potential artificial nuclease.

Quantification of body iron and iron absorption in the REDS-II Donor Iron Status Evaluation (RISE) study.

Science.gov (United States)

Kiss, Joseph E; Birch, Rebecca J; Steele, Whitney R; Wright, David J; Cable, Ritchard G

2017-07-01

Repeated blood donation alters the iron balance of blood donors. We quantified these effects by analyzing changes in body iron as well as calculating iron absorbed per day for donors enrolled in a prospective study. For 1308 donors who completed a final study visit, we calculated total body iron at the enrollment and final visits and the change in total body iron over the course of the study. Taking into account iron lost from blood donations during the study and obligate losses, we also calculated the average amount of iron absorbed per day. First-time/reactivated donors at enrollment had iron stores comparable to previous general population estimates. Repeat donors had greater donation intensity and greater mean iron losses than first-time/reactivated donors, yet they had little change in total body iron over the study period, whereas first-time/reactivated donors had an average 35% drop. There was higher estimated iron absorption in the repeat donors (men: 4.49 mg/day [95% confidence interval [CI], 4.41-4.58 mg/day]; women: 3.75 mg/day [95% CI, 3.67-3.84 mg/day]) compared with estimated iron absorption in first-time/reactivated donors (men: 2.89 mg/day [95% CI, 2.75-3.04 mg/day]; women: 2.76 mg/day [95% CI, 2.64-2.87 mg/day]). The threshold for negative estimated iron stores (below "0" mg/kg stores) was correlated with the development of anemia at a plasma ferritin value of 10 ng/mL. These analyses provide quantitative data on changes in estimated total body iron for a broad spectrum of blood donors. In contrast to using ferritin alone, this model allows assessment of the iron content of red blood cells and the degree of both iron surplus and depletion over time. © 2017 AABB.

Very Large Distance Education Systems: The Case of China. ZIFF Papiere 94.

Science.gov (United States)

Keegan, Desmond

One answer to the magnitude of the world education crisis is the provision of very large education systems, capable of enrolling 100,000 students or more. The largest distance system is the Dianda or Chinese Radio and Television University (CRTVU) system. Dianda is best described as a network of one central open university that does not enroll…

The impact of fish and the commercial marine harvest on the ocean iron cycle.

Directory of Open Access Journals (Sweden)

Allison R Moreno

Full Text Available Although iron is the fourth most abundant element in the Earth's crust, bioavailable iron limits marine primary production in about one third of the ocean. This lack of iron availability has implications in climate change because the removal of carbon dioxide from the atmosphere by phytoplankton requires iron. Using literature values for global fish biomass estimates, and elemental composition data we estimate that fish biota store between 0.7-7 × 10(11 g of iron. Additionally, the global fish population recycles through excretion between 0.4-1.5 × 10(12 g of iron per year, which is of a similar magnitude as major recognized sources of iron (e.g. dust, sediments, ice sheet melting. In terms of biological impact this iron could be superior to dust inputs due to the distributed deposition and to the greater solubility of fecal pellets compared to inorganic minerals. To estimate a loss term due to anthropogenic activity the total commercial catch for 1950 to 2010 was obtained from the Food and Agriculture Organization of the United Nations. Marine catch data were separated by taxa. High and low end values for elemental composition were obtained for each taxonomic category from the literature and used to calculate iron per mass of total harvest over time. The marine commercial catch is estimated to have removed 1-6 × 10(9 g of iron in 1950, the lowest values on record. There is an annual increase to 0.7-3 × 10(10 g in 1996, which declines to 0.6-2 × 10(10 g in 2010. While small compared to the total iron terms in the cycle, these could have compounding effects on distribution and concentration patterns globally over time. These storage, recycling, and export terms of biotic iron are not currently included in ocean iron mass balance calculations. These data suggest that fish and anthropogenic activity should be included in global oceanic iron cycles.

The accuracy of geometries for iron porphyrin complexes from density functional theory

DEFF Research Database (Denmark)

Rydberg, Patrik Åke Anders; Olsen, Lars

2009-01-01

functionals is evaluated with regard to how they reproduce experimental structures. Seven different functionals (BP86, PBE, PBE0, TPSS, TPSSH, B3LYP, and B97-D) are used to study eight different iron porphyrin complexes. The results show that the TPSSH, PBE0, and TPSS functionals give the best results...... (absolute bond distance deviations of 0.015-0.016 A), but the geometries are well-reproduced by all functionals except B3LYP. We also test four different basis sets of double-zeta quality, and we find that a combination of double-zeta basis set of Schafer et al. on the iron atom and the 6-31G* basis set...

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... Research Home / < Back To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer en español Iron-deficiency ... iron-deficiency anemia. Blood tests to screen for iron-deficiency anemia To screen for iron-deficiency anemia, your doctor ...

49 CFR 192.373 - Service lines: Cast iron and ductile iron.

Science.gov (United States)

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Service lines: Cast iron and ductile iron. 192.373... Regulators, and Service Lines § 192.373 Service lines: Cast iron and ductile iron. (a) Cast or ductile iron... cast iron pipe or ductile iron pipe is installed for use as a service line, the part of the service...

The Carnegie-Chicago Hubble Program. I. An Independent Approach to the Extragalactic Distance Scale Using Only Population II Distance Indicators

Science.gov (United States)

Beaton, Rachael L.; Freedman, Wendy L.; Madore, Barry F.; Bono, Giuseppe; Carlson, Erika K.; Clementini, Gisella; Durbin, Meredith J.; Garofalo, Alessia; Hatt, Dylan; Jang, In Sung; Kollmeier, Juna A.; Lee, Myung Gyoon; Monson, Andrew J.; Rich, Jeffrey A.; Scowcroft, Victoria; Seibert, Mark; Sturch, Laura; Yang, Soung-Chul

2016-12-01

We present an overview of the Carnegie-Chicago Hubble Program, an ongoing program to obtain a 3% measurement of the Hubble constant (H 0) using alternative methods to the traditional Cepheid distance scale. We aim to establish a completely independent route to H 0 using RR Lyrae variables, the tip of the red giant branch (TRGB), and Type Ia supernovae (SNe Ia). This alternative distance ladder can be applied to galaxies of any Hubble type, of any inclination, and, using old stars in low-density environments, is robust to the degenerate effects of metallicity and interstellar extinction. Given the relatively small number of SNe Ia host galaxies with independently measured distances, these properties provide a great systematic advantage in the measurement of H 0 via the distance ladder. Initially, the accuracy of our value of H 0 will be set by the five Galactic RR Lyrae calibrators with Hubble Space Telescope Fine-Guidance Sensor parallaxes. With Gaia, both the RR Lyrae zero-point and TRGB method will be independently calibrated, the former with at least an order of magnitude more calibrators and the latter directly through parallax measurement of tip red giants. As the first end-to-end “distance ladder” completely independent of both Cepheid variables and the Large Magellanic Cloud, this path to H 0 will allow for the high-precision comparison at each rung of the traditional distance ladder that is necessary to understand tensions between this and other routes to H 0. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs #13472 and #13691.

Spectroscopic investigation of Bovine Liver Catalase interactions with a novel phen-imidazole derivative of platinum.

Science.gov (United States)

Ghobadi, Roohollah; Divsalar, Adeleh; Harifi-Mood, Ali Reza; Saboury, Ali Akbar

2018-02-01

Successful clinical experience of using cisplatin and its derivatives in cancer therapy has encouraged scientists to synthesize new metal complexes with the aim of interacting with special targets such as proteins In this regard, biological effects of [Pt(FIP)(Phen)](NO 3 ) 2 compound which contains a novel phen-imidazole ligand, FIP, was investigated on bovine liver catalase (BLC) structure and function. Various spectroscopic methods such as UV-visible, fluorescence, and circular dichroism (CD) were applied at two temperatures 25 and 37°C for kinetics and structural studies. As a consequence, the enzymatic activity decreased slightly with increasing the platinum compound's concentration up to 30 μM and then remained constant at near 80% after this concentration. On the other hand, the fluorescence quenching measurements revealed that despite slight changes in activity, catalase experiences notable alterations in three-dimensional environment around the chromophores of the enzyme structure with increasing platinum complex concentration. Moreover, quenching data showed that BLC has two binding sites for Pt complex and hydrogen bonding interactions play a major role in the binding process. Furthermore, CD spectroscopy data showed that Pt(II) complex induces significant decrease in α-helix content of the secondary structure of BLC, but notable increase in random coil proportion accompanying a slight decrease in β-sheet content. All in all, hydrogen bonding interactions which are mainly involved in the binding process of the novel phen-imidazole compound to BLC significantly alter the protein structure but slightly change its function. This might be a promising outcome for chemotherapists and medicinal chemists to investigate in vivo properties of this novel metal complex with significant binding tendency to a macromolecule in the low concentrations without decreasing its intrinsic function.

Effect of the number of iron oxide nanoparticle layers on the magnetic properties of nanocomposite LbL assemblies

International Nuclear Information System (INIS)

Dincer, Ilker; Tozkoparan, Onur; German, Sergey V.; Markin, Alexey V.; Yildirim, Oguz; Khomutov, Gennady B.; Gorin, Dmitry A.; Venig, Sergey B.; Elerman, Yalcin

2012-01-01

Aqueous colloidal suspension of iron oxide nanoparticles has been synthesized. Z-potential of iron oxide nanoparticles stabilized by citric acid was −35±3 mV. Iron oxide nanoparticles have been characterized by the light scattering method and transmission electron microscopy. The polyelectrolyte/iron oxide nanoparticle thin films with different numbers of iron oxide nanoparticle layers have been prepared on the surface of silicon substrates via the layer-by-layer assembly technique. The physical properties and chemical composition of nanocomposite thin films have been studied by atomic force microscopy, magnetic force microscopy, magnetization measurements, Raman spectroscopy. Using the analysis of experimental data it was established, that the magnetic properties of nanocomposite films depended on the number of iron oxide nanoparticle layers, the size of iron oxide nanoparticle aggregates, the distance between aggregates, and the chemical composition of iron oxide nanoparticles embedded into the nanocomposite films. The magnetic permeability of nanocomposite coatings has been calculated. The magnetic permeability values depend on the number of iron oxide nanoparticle layers in nanocomposite film. - Highlights: ► The magnetic properties of nanocomposite films depended on the number of iron oxide nanoparticle layers. ► The iron oxide nanoparticle phase in nanocomposite coatings is a mixture of magnetite and maghemite phases. ► The magnetite and maghemite phases depend on a number of iron oxide nanoparticle layers because the iron oxide nanoparticles are oxidized from magnetite to maghemite.

Investigation on relationship between epicentral distance and growth curve of initial P-wave propagating in local heterogeneous media for earthquake early warning system

Science.gov (United States)

Okamoto, Kyosuke; Tsuno, Seiji

2015-10-01

In the earthquake early warning (EEW) system, the epicenter location and magnitude of earthquakes are estimated using the amplitude growth rate of initial P-waves. It has been empirically pointed out that the growth rate becomes smaller as epicentral distance becomes far regardless of the magnitude of earthquakes. So, the epicentral distance can be estimated from the growth rate using this empirical relationship. However, the growth rates calculated from different earthquakes at the same epicentral distance mark considerably different values from each other. Sometimes the growth rates of earthquakes having the same epicentral distance vary by 104 times. Qualitatively, it has been considered that the gap in the growth rates is due to differences in the local heterogeneities that the P-waves propagate through. In this study, we demonstrate theoretically how local heterogeneities in the subsurface disturb the relationship between the growth rate and the epicentral distance. Firstly, we calculate seismic scattered waves in a heterogeneous medium. First-ordered PP, PS, SP, and SS scatterings are considered. The correlation distance of the heterogeneities and fractional fluctuation of elastic parameters control the heterogeneous conditions for the calculation. From the synthesized waves, the growth rate of the initial P-wave is obtained. As a result, we find that a parameter (in this study, correlation distance) controlling heterogeneities plays a key role in the magnitude of the fluctuation of the growth rate. Then, we calculate the regional correlation distances in Japan that can account for the fluctuation of the growth rate of real earthquakes from 1997 to 2011 observed by K-NET and KiK-net. As a result, the spatial distribution of the correlation distance shows locality. So, it is revealed that the growth rates fluctuate according to the locality. When this local fluctuation is taken into account, the accuracy of the estimation of epicentral distances from initial P

Comparative study of efficacy, tolerability and compliance of oral iron preparations (iron edetate, iron polymatose complex) and intramuscular iron sorbitol in iron deficiency anaemia in children

International Nuclear Information System (INIS)

Afzal, M.; Qureshi, S.M.; Lutafullah, M.

2009-01-01

To compare the efficacy, tolerability and compliance of oral iron preparations(iron edetate and Iron polymaltose complex) with each other and with intramuscular iron sorbitol in iron deficiency anaemia in children. A Randomized Controlled Trial (RCT) was carried out at the Paediatric Department of Combined Military Hospital (CMH) from January 2006 to December 2007. In total 146 children, up to 12 years age having haemoglobin (Hb%) less than 8 gm% were included. They were randomly distributed into three groups. Group A(64 cases) received oral sodium iron edetate (SIE), Group B (40 cases) received oral iron polymaltose complex (IPC) and group C (42 cases) received intramuscular iron sorbitol (IS) in recommended dosages. Rise in Hb%>10 gm% was kept as desired target. Maximum duration of treatment planned was 2 weeks for parenteral iron (group C) and 12 weeks for oral iron (groups A and B). Haematological parameters- Hb%, mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC) were measured at induction followed at 2 weeks, 4 weeks, 8 weeks and 12 weeks after start of treatment. Compliance and drop out rates were determined on each visit. Data was analyzed using SPSS version 10. ANOVA was used to analyze difference in rise in Hb% at various intervals. Statistically significant increase in mean Hb%, MCV, MCHC after 02 weeks was observed in group C (IS). Rise in these parameters became significant in group A (SIE) and B (IPC) after 04 weeks. Persistent rise was observed in oral groups at 08 and 12 weeks. Rise in Hb% was much faster in group C (IS). It took 2 weeks to achieve mean Hb% > 10 gm% and compliance rate was 40.5%, while to achieve same target, duration required was 8 weeks in group A (SIE) and 12 weeks in group B (IPC) and compliance rate was 39% and 30% respectively. Adverse effects were much more common with group A (SIE) as compared to other two groups. Intramuscular iron sorbitol is a reliable and

Extreme value distribution of earthquake magnitude

Science.gov (United States)

Zi, Jun Gan; Tung, C. C.

1983-07-01

Probability distribution of maximum earthquake magnitude is first derived for an unspecified probability distribution of earthquake magnitude. A model for energy release of large earthquakes, similar to that of Adler-Lomnitz and Lomnitz, is introduced from which the probability distribution of earthquake magnitude is obtained. An extensive set of world data for shallow earthquakes, covering the period from 1904 to 1980, is used to determine the parameters of the probability distribution of maximum earthquake magnitude. Because of the special form of probability distribution of earthquake magnitude, a simple iterative scheme is devised to facilitate the estimation of these parameters by the method of least-squares. The agreement between the empirical and derived probability distributions of maximum earthquake magnitude is excellent.

Adolescents with Developmental Dyscalculia Do Not Have a Generalized Magnitude Deficit - Processing of Discrete and Continuous Magnitudes.

Science.gov (United States)

McCaskey, Ursina; von Aster, Michael; O'Gorman Tuura, Ruth; Kucian, Karin

2017-01-01

The link between number and space has been discussed in the literature for some time, resulting in the theory that number, space and time might be part of a generalized magnitude system. To date, several behavioral and neuroimaging findings support the notion of a generalized magnitude system, although contradictory results showing a partial overlap or separate magnitude systems are also found. The possible existence of a generalized magnitude processing area leads to the question how individuals with developmental dyscalculia (DD), known for deficits in numerical-arithmetical abilities, process magnitudes. By means of neuropsychological tests and functional magnetic resonance imaging (fMRI) we aimed to examine the relationship between number and space in typical and atypical development. Participants were 16 adolescents with DD (14.1 years) and 14 typically developing (TD) peers (13.8 years). In the fMRI paradigm participants had to perform discrete (arrays of dots) and continuous magnitude (angles) comparisons as well as a mental rotation task. In the neuropsychological tests, adolescents with dyscalculia performed significantly worse in numerical and complex visuo-spatial tasks. However, they showed similar results to TD peers when making discrete and continuous magnitude decisions during the neuropsychological tests and the fMRI paradigm. A conjunction analysis of the fMRI data revealed commonly activated higher order visual (inferior and middle occipital gyrus) and parietal (inferior and superior parietal lobe) magnitude areas for the discrete and continuous magnitude tasks. Moreover, no differences were found when contrasting both magnitude processing conditions, favoring the possibility of a generalized magnitude system. Group comparisons further revealed that dyscalculic subjects showed increased activation in domain general regions, whilst TD peers activate domain specific areas to a greater extent. In conclusion, our results point to the existence of a

Results of the First American Prospective Study of Intravenous Iron in Oral Iron-Intolerant Iron-Deficient Gravidas.

Science.gov (United States)

Auerbach, Michael; James, Stephanie E; Nicoletti, Melissa; Lenowitz, Steven; London, Nicola; Bahrain, Huzefa F; Derman, Richard; Smith, Samuel

2017-12-01

Anemia affects up to 42% of gravidas. Neonatal iron deficiency is associated with low birth weight, delayed growth and development, and increased cognitive and behavioral abnormalities. While oral iron is convenient, up to 70% report significant gastrointestinal toxicity. Intravenous iron formulations allowing replacement in one visit with favorable side-effect profiles decrease rates of anemia with improved hemoglobin responses and maternal fetal outcomes. Seventy-four oral iron-intolerant, second- and third-trimester iron-deficient gravidas were questioned for oral iron intolerance and treated with intravenous iron. All received 1000 mg of low-molecular-weight iron dextran in 250 mL normal saline. Fifteen minutes after a test dose, the remainder was infused over the balance of 1 hour. Subjects were called at 1, 2, and 7 days to assess delayed reactions. Four weeks postinfusion or postpartum, hemoglobin levels and iron parameters were measured. Paired t test was used for hemoglobin and iron; 58/73 women were questioned about interval growth and development of their babies. Seventy-three of 74 enrolled subjects completed treatment. Sixty had paired pre- and posttreatment data. The mean pre- and posthemoglobin concentrations were 9.7 and 10.8 g/dL (P iron deficiency anemia. Intravenous iron has less toxicity and is more effective, supporting moving it closer to frontline therapy. Copyright © 2017 Elsevier Inc. All rights reserved.

Studying Irony Detection Beyond Ironic Criticism: Let's Include Ironic Praise

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Richard Bruntsch

2017-04-01

Full Text Available Studies of irony detection have commonly used ironic criticisms (i.e., mock positive evaluation of negative circumstances as stimulus materials. Another basic type of verbal irony, ironic praise (i.e., mock negative evaluation of positive circumstances is largely absent from studies on individuals' aptitude to detect verbal irony. However, it can be argued that ironic praise needs to be considered in order to investigate the detection of irony in the variety of its facets. To explore whether the detection ironic praise has a benefit beyond ironic criticism, three studies were conducted. In Study 1, an instrument (Test of Verbal Irony Detection Aptitude; TOVIDA was constructed and its factorial structure was tested using N = 311 subjects. The TOVIDA contains 26 scenario-based items and contains two scales for the detection of ironic criticism vs. ironic praise. To validate the measurement method, the two scales of the TOVIDA were experimentally evaluated with N = 154 subjects in Study 2. In Study 3, N = 183 subjects were tested to explore personality and ability correlates of the two TOVIDA scales. Results indicate that the co-variance between the ironic TOVIDA items was organized by two inter-correlated but distinct factors: one representing ironic praise detection aptitude and one representing ironic criticism detection aptitude. Experimental validation showed that the TOVIDA items truly contain irony and that item scores reflect irony detection. Trait bad mood and benevolent humor (as a facet of the sense of humor were found as joint correlates for both ironic criticism and ironic praise detection scores. In contrast, intelligence, trait cheerfulness, and corrective humor were found as unique correlates of ironic praise detection scores, even when statistically controlling for the aptitude to detect ironic criticism. Our results indicate that the aptitude to detect ironic praise can be seen as distinct from the aptitude to detect ironic

Reactivity of Hydroxy and Amino Derivatives of 2-Phenyl-1H-imidazoline and 2-Phenyl-1H-imidazole toward Isocyanates: Synthesis of Appropriate Carbamates and Ureas

Czech Academy of Sciences Publication Activity Database

Pařík, P.; Jansa, J.; Holešová, S.; Marek, Aleš; Klimešová, V.

2013-01-01

Roč. 50, č. 4 (2013), s. 903-910 ISSN 0022-152X Grant - others:GA ČR(CZ) GA205/08/0869 Institutional support: RVO:61388963 Keywords : elevated-temperature * hydrolysis * imidazoles * alkylation Subject RIV: CC - Organic Chemistry Impact factor: 0.873, year: 2013

Biological applications of zinc imidazole framework through protein encapsulation

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Pawan Kumar

2015-12-01

Full Text Available Abstract The robustness of biomolecules is always a significant challenge in the application of biostorage in biotechnology or pharmaceutical research. To learn more about biostorage in porous materials, we investigated the feasibility of using zeolite imidazolate framework (ZIF-8 with respect to protein encapsulation. Here, bovine serum albumin (BSA was selected as a model protein for encapsulation with the synthesis of ZIF-8 using water as a media. ZIF-8 exhibited excellent protein adsorption capacity through successive adsorption of free BSA with the formation of hollow crystals. The loading of protein in ZIF-8 crystals is affected by the molecular weight due to diffusion-limited permeation inside the crystals and also by the affinity of the protein to the pendent group on the ZIF-8 surface. The polar nature of BSA not only supported adsorption on the solid surface, but also enhanced the affinity of crystal spheres through weak coordination interactions with the ZIF-8 framework. The novel approach tested in this study was therefore successful in achieving protein encapsulation with porous, biocompatible, and decomposable microcrystalline ZIF-8. The presence of both BSA and FITC–BSA in ZIF-8 was confirmed consistently by spectroscopy as well as optical and electron microscopy.

Absorption of medicamental iron and iron from food

International Nuclear Information System (INIS)

Reizenstein, P.; Carlmark, B.; Ehn, L.; Forsberg, K.; Hoeglund, S.; Terpstra, T.

1976-01-01

Methods are reviewed for the measurement of iron absorption. The chemical balance method has been almost entirely supplanted by radioisotope methods, which include notably whole-body counting and measurement of incorporation of radioiron into red cells. A survey is also given of the various conditions that influence iron absorption, including chemical form of iron, amount of iron, accompanying diet. Absorption tests must be conducted under relevant conditions. (author)

The Cognitive Estimation Task Is Nonunitary: Evidence for Multiple Magnitude Representation Mechanisms Among Normative and ADHD College Students

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Sarit Ashkenazi

2017-02-01

Full Text Available There is a current debate on whether the cognitive system has a shared representation for all magnitudes or whether there are unique representations. To investigate this question, we used the Biber cognitive estimation task. In this task, participants were asked to provide estimates for questions such as, “How many sticks of spaghetti are in a package?” The task uses different estimation categories (e.g., time, numerical quantity, distance, and weight to look at real-life magnitude representations. Experiment 1 assessed (N = 95 a Hebrew version of the Biber Cognitive Estimation Task and found that different estimation categories had different relations, for example, weight, time, and distance shared variance, but numerical estimation did not. We suggest that numerical estimation does not require the use of measurement in units, hence, it represents a more “pure” numerical estimation. Experiment 2 found that different factors explain individual abilities in different estimation categories. For example, numerical estimation was predicted by preverbal innate quantity understanding (approximate number sense and working memory, whereas time estimations were supported by IQ. These results demonstrate that cognitive estimation is not a unified construct.

Iron-Deficiency Anemia

Science.gov (United States)

... To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer en español Iron-deficiency ... anemia. Blood tests to screen for iron-deficiency anemia To screen for iron-deficiency anemia, your doctor ...

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... risk for iron-deficiency anemia, including: Vegetarian or vegan eating patterns. Not eating enough iron-rich foods, ... iron-fortified foods that have iron added. Vegetarian diets can provide enough iron if you choose nonmeat ...

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer en español Iron-deficiency anemia is a ... address the cause of your iron deficiency, such as any underlying bleeding. If undiagnosed or untreated, iron- ...

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer en español Iron-deficiency ... anemia. Blood tests to screen for iron-deficiency anemia To screen for iron-deficiency anemia, your doctor ...

Magnitude and Correlates of Low Birth Weight at Term in Rural Wardha, Central India

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Kumar V

2016-05-01

Full Text Available Introduction: Birth weight is one of the most important determinant of the neonatal and infant survival. The goal of reducing low birth weight incidence by at least one third between 2000 and 2010 was one of the major goals in ‘A World Fit for Children’. The prevention of low birth weight is a public health priority, particularly in developing countries with high magnitude. Knowledge regarding magnitude and correlates help prevent the condition. Hence, the present study was carried out to study the magnitude and the correlates of low birth weight. Methodology: Two hundred and six newborn babies were recruited on a birth cohort from two Primary Health Centres (PHC of Wardha district to study growth in first year of life. Here, we present the baseline analysis of 172 children who were born full term to study the correlates of low birth weight babies born full term. The children were recruited within first week of their birth. Data was collected on socio-demographic profile, birth history, and maternal characteristics. Proportion of low birth weight was expressed in percentage along with 95% confidence interval. Univariate and multivariate logistic regression was used to study the correlates. Findings are expressed in odds ratios with their 95% confidence intervals. Results: The magnitude of low birth weight at term was found to be 33.1% (95% CI: 26.4%-40.4%. On univariate analysis, significant correlates of low birth weight were consumption of less than 50 iron-folic acid tables and being born to than mother. On multivariate analysis, the significant correlates were female sex of child (OR=2.856, being born to thin mother (OR=5.320, consumption of less than 50 tablets (OR=4.648, and complications of pregnancy (OR=2.917. Conclusions: The magnitude of low birth weight is very high and modifiable correlates of low birth weight are nutritional status of mother, lower consumption of IFA tablets and complications of pregnancy.

Magnitudes and Moment-Duration Scaling of Low-Frequency Earthquakes Beneath Southern Vancouver Island

Science.gov (United States)

Bostock, M. G.; Thomas, A.; Rubin, A. M.; Savard, G.; Chuang, L. Y.

2015-12-01

We employ 130 low-frequency-earthquake (LFE) templates representing tremor sources on the plate boundary below southern Vancouver Island to examine LFE magnitudes. Each template is assembled from 100's to 1000's of individual LFEs, representing over 300,000 independent detections from major episodic-tremor-and- slip (ETS) events between 2003 and 2013. Template displacement waveforms for direct P- and S-waves at near epicentral distances are remarkably simple at many stations, approaching the zero-phase, single pulse expected for a point dislocation source in a homogeneous medium. High spatio-temporal precision of template match-filtered detections facilitates precise alignment of individual LFE detections and analysis of waveforms. Upon correction for 1-D geometrical spreading, attenuation, free-surface magnification and radiation pattern, we solve a large, sparse linear system for 3-D path corrections and LFE magnitudes for all detections corresponding to a single ETS template. The spatio-temporal distribution of magnitudes indicates that typically half the total moment release occurs within the first 12-24 hours of LFE activity during an ETS episode when tidal sensitity is low. The remainder is released in bursts over several days, particularly as spatially extensive RTRs, during which tidal sensitivity is high. RTR's are characterized by large magnitude LFEs, and are most strongly expressed in the updip portions of the ETS transition zone and less organized at downdip levels. LFE magnitude-frequency relations are better described by power-law than exponential distributions although they exhibit very high b-values ≥ 6. We examine LFE moment-duration scaling by generating templates using detections for limiting magnitude ranges MW<1.5, MW≥ 2.0. LFE duration displays a weaker dependence upon moment than expected for self-similarity, suggesting that LFE asperities are limited in dimension and that moment variation is dominated by slip. This behaviour implies

Electric properties and fabrication of IMI-O LB films containing the imidazole group

CERN Document Server

Yoo, S Y; Kwon, Y S; Park, J C

1999-01-01

We fabricated an IMI-O polymer containing an imidazole group that could form a complex structure between the monolayer and the metal ions at the air-water interface. Also, the monolayer behavior at the air-water interface and the electrical properties of metal-complexed Langmuir-Blodgett (LB) films were investigated by using Brewster angle microscopy (BAM) and current-voltage(I-V) measurements. The difference in the BAM images between the pure water and the aqueous metal ions is attributed to the interactions of the copolymers with the metal ions at the interface and the consequent change of the monolayer organization. In the I-V characteristics, the current for LB films with different metal ion depended on the quantity of the metal-ion complexed with the LB film due to the interaction between the metal ion and the IMI-O polymer.

Investigation of the Linker Swing Motion in the Zeolitic Imidazolate Framework ZIF-90

KAUST Repository

Zheng, Bin

2018-03-13

The linker swing motion in the zeolitic imidazolate framework ZIF-90 is investigated by density functional theory (DFT) calculation, molecular dynamics (MD) and grand-canonical Monte Carlo (GCMC) simulations. The relation between the terminal aldehyde group rotation and the linker swing motion is revealed. The extremely high activation energy of the linker swing motion in ZIF-90 can be attributed to the asymmetric geometry and electron distribution of aldehyde groups. The change in the gate structure resulting from the linker rotation is used to understand the guest adsorption in ZIF-90. This study shows that it is possible to tune the linker swing motion and then the properties of ZIF-90 by manipulating the terminal group rotation. The results highlight the importance of considering the internal freedom effects to correctly describe the linker swing motion and the flexibility of metal-organic frameworks (MOFs).

Serum iron and total iron binding capacity levels among the abo ...

African Journals Online (AJOL)

Iron deficiency anaemia is a common tropical disease. Iron plays a very important role in the human body. The understanding of the different blood groups ability to retain iron in their system can give an insight into their ability to handle the disease Iron deficiency anaemia. Serum Iron, Total Iron Binding Capacity (TIBC) and ...

Zinc deficiency-induced iron accumulation, a consequence of alterations in iron regulatory protein-binding activity, iron transporters, and iron storage proteins.

Science.gov (United States)

Niles, Brad J; Clegg, Michael S; Hanna, Lynn A; Chou, Susan S; Momma, Tony Y; Hong, Heeok; Keen, Carl L

2008-02-22

One consequence of zinc deficiency is an elevation in cell and tissue iron concentrations. To examine the mechanism(s) underlying this phenomenon, Swiss 3T3 cells were cultured in zinc-deficient (D, 0.5 microM zinc), zinc-supplemented (S, 50 microM zinc), or control (C, 4 microM zinc) media. After 24 h of culture, cells in the D group were characterized by a 50% decrease in intracellular zinc and a 35% increase in intracellular iron relative to cells in the S and C groups. The increase in cellular iron was associated with increased transferrin receptor 1 protein and mRNA levels and increased ferritin light chain expression. The divalent metal transporter 1(+)iron-responsive element isoform mRNA was decreased during zinc deficiency-induced iron accumulation. Examination of zinc-deficient cells revealed increased binding of iron regulatory protein 2 (IRP2) and decreased binding of IRP1 to a consensus iron-responsive element. The increased IRP2-binding activity in zinc-deficient cells coincided with an increased level of IRP2 protein. The accumulation of IRP2 protein was independent of zinc deficiency-induced intracellular nitric oxide production but was attenuated by the addition of the antioxidant N-acetylcysteine or ascorbate to the D medium. These data support the concept that zinc deficiency can result in alterations in iron transporter, storage, and regulatory proteins, which facilitate iron accumulation.

2D→3D polycatenated and 3D→3D interpenetrated metal–organic frameworks constructed from thiophene-2,5-dicarboxylate and rigid bis(imidazole) ligands

Energy Technology Data Exchange (ETDEWEB)

Erer, Hakan [Department of Chemistry, Faculty of Arts and Sciences, Eskişehir Osmangazi University, 26480 Eskişehir (Turkey); Yeşilel, Okan Zafer, E-mail: yesilel@ogu.edu.tr [Department of Chemistry, Faculty of Arts and Sciences, Eskişehir Osmangazi University, 26480 Eskişehir (Turkey); Arıcı, Mürsel [Department of Chemistry, Faculty of Arts and Sciences, Eskişehir Osmangazi University, 26480 Eskişehir (Turkey); Keskin, Seda [Department of Chemical and Biological Engineering, Koç University, İstanbul (Turkey); Büyükgüngör, Orhan [Department of Physics, Faculty of Arts and Sciences, Ondokuz Mayıs University, 55139 Samsun (Turkey)

2014-02-15

Hydrothermal reactions of rigid 1,4-bis(imidazol-1-yl)benzene (dib) and 1,4-bis(imidazol-1-yl)-2,5-dimethylbenzene (dimb) with deprotonated thiophene-2,5-dicarboxylic acid (H{sub 2}tdc) in the presence of Zn(II) and Cd(II) salts in H{sub 2}O produced three new metal–organic frameworks, namely, [Zn(µ-tdc)(H{sub 2}O)(µ-dib)]{sub n} (1), [Cd(µ-tdc)(H{sub 2}O)(µ-dib)]{sub n} (2), and ([Cd{sub 2}(µ{sub 3}-tdc){sub 2}(µ-dimb){sub 2}]·(H{sub 2}O)){sub n}(3). These MOFs were characterized by FT-IR spectroscopy, elemental, thermal (TG, DTA, DTG and DSC), and single-crystal X-ray diffraction analyses. Isomorphous complexes 1 and 2 reveal polycatenated 2D+2D→3D framework based on an undulated (4,4)-sql layer. Complex 3 exhibits a new 4-fold interpenetrating 3D framework with the point symbol of 6{sup 6}. Molecular simulations were used to assess the potentials of the complexes for H{sub 2} storage application. Moreover, these coordination polymers exhibit blue fluorescent emission bands in the solid state at room temperature. - Graphical abstract: In this study, hydrothermal reactions of rigid 1,4-bis(imidazol-1-yl)benzene (dib) and 1,4-bis(imidazol-1-yl)-2,5-dimethylbenzene (dimb) with deprotonated thiophene-2,5-dicarboxylic acid (H{sub 2}tdc) in the presence of Zn(II) and Cd(II) salts in H{sub 2}O produced three new metal–organic frameworks. Isomorphous complexes 1 and 2 reveal polycatenated 2D+2D→3D framework based on an undulated (4,4)-sql layer. Complex 3 exhibits a new 4-fold interpenetrating 3D framework with the point symbol of 6{sup 6}. Molecular simulations were used to assess the potentials of the complexes for H{sub 2} storage application. These coordination polymers exhibit blue fluorescent emission bands in the solid state at room temperature. Display Omitted - Highlights: • Complexes 1 and 2 display polycatenated 2D+2D→3D framework. • Complex 3 exhibits a new 4-fold interpenetrating 3D framework. • Complex 1 adsorbs the highest amount of

Iron content and solubility in dust from high-alpine snow along a north-south transect of High Asia

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Guangjian Wu

2012-04-01

Full Text Available This study describes the dissolved and insoluble iron fraction of dust (mineral aerosol in high-alpine snow samples collected along a north-south transect across High Asia (Eastern Tien Shan, Qilian Shan, and Southern Tibetan Plateau. This dust provides the basic chemical properties of mid- and high-level tropospheric Asian dust that can supply the limiting iron nutrient for phytoplankton growth in the North Pacific. The iron content in Asian dust averages 4.95% in Eastern Tien Shan, 3.38–5.41% along Qilian Shan and 3.85% in the Southern Tibetan Plateau. The iron fractional solubility averages about 0.25% in Eastern Tien Shan, 0.05–2% along Qilian Shan and 1.5% in the Southern Tibetan Plateau. Among the controlling factors that can affect iron solubility in Asian dust, such as dust composition and particle grain size, acidity seems to be the most significant and can increase the iron solubility by one or two orders of magnitude with acidification of pH=0.66. Our results reveal that iron solubility of dust in the remote downwind sites is higher than that in high-alpine snow, confirming the strong pH-dependence of iron solubility, and indicating that Asian dust shows a large variation in iron solubility on a regional scale.

Mammalian iron metabolism and its control by iron regulatory proteins☆

Science.gov (United States)

Anderson, Cole P.; Shen, Lacy; Eisenstein, Richard S.; Leibold, Elizabeth A.

2013-01-01

Cellular iron homeostasis is maintained by iron regulatory proteins 1 and 2 (IRP1 and IRP2). IRPs bind to iron-responsive elements (IREs) located in the untranslated regions of mRNAs encoding protein involved in iron uptake, storage, utilization and export. Over the past decade, significant progress has been made in understanding how IRPs are regulated by iron-dependent and iron-independent mechanisms and the pathological consequences of IRP2 deficiency in mice. The identification of novel IREs involved in diverse cellular pathways has revealed that the IRP–IRE network extends to processes other than iron homeostasis. A mechanistic understanding of IRP regulation will likely yield important insights into the basis of disorders of iron metabolism. This article is part of a Special Issue entitled: Cell Biology of Metals. PMID:22610083

The Araucaria Project: The Distance to the Fornax Dwarf Galaxy from Near-infrared Photometry of RR Lyrae Stars

Science.gov (United States)

Karczmarek, Paulina; Pietrzyński, Grzegorz; Górski, Marek; Gieren, Wolfgang; Bersier, David

2017-12-01

We have obtained single-phase near-infrared (NIR) magnitudes in the J and K bands for 77 RR Lyrae (RRL) stars in the Fornax Dwarf Spheroidal Galaxy. We have used different theoretical and empirical NIR period-luminosity-metallicity calibrations for RRL stars to derive their absolute magnitudes, and found a true, reddening-corrected distance modulus of 20.818+/- 0.015{{(statistical)}}+/- 0.116{{(systematic)}} mag. This value is in excellent agreement with the results obtained within the Araucaria Project from the NIR photometry of red clump stars (20.858 ± 0.013 mag), the tip of the red giant branch (20.84+/- 0.04+/- 0.14 mag), as well as with other independent distance determinations to this galaxy. The effect of metallicity and reddening is substantially reduced in the NIR domain, making this method a robust tool for accurate distance determination at the 5% level. This precision is expected to reach the level of 3% once the zero points of distance calibrations are refined thanks to the Gaia mission. NIR period-luminosity-metallicity relations of RRL stars are particularly useful for distance determinations to galaxies and globular clusters up to 300 kpc, that lack young standard candles, like Cepheids. Based on data collected with the VLT/HAWK-I instrument at ESO Paranal Observatory, Chile, as a part of programme 082.D-0123(B).

Iron-binding haemerythrin RING ubiquitin ligases regulate plant iron responses and accumulation

Science.gov (United States)

Kobayashi, Takanori; Nagasaka, Seiji; Senoura, Takeshi; Itai, Reiko Nakanishi; Nakanishi, Hiromi; Nishizawa, Naoko K.

2013-01-01

Iron is essential for most living organisms. Plants transcriptionally induce genes involved in iron acquisition under conditions of low iron availability, but the nature of the deficiency signal and its sensors are unknown. Here we report the identification of new iron regulators in rice, designated Oryza sativa Haemerythrin motif-containing Really Interesting New Gene (RING)- and Zinc-finger protein 1 (OsHRZ1) and OsHRZ2. OsHRZ1, OsHRZ2 and their Arabidopsis homologue BRUTUS bind iron and zinc, and possess ubiquitination activity. OsHRZ1 and OsHRZ2 are susceptible to degradation in roots irrespective of iron conditions. OsHRZ-knockdown plants exhibit substantial tolerance to iron deficiency, and accumulate more iron in their shoots and grains irrespective of soil iron conditions. The expression of iron deficiency-inducible genes involved in iron utilization is enhanced in OsHRZ-knockdown plants, mostly under iron-sufficient conditions. These results suggest that OsHRZ1 and OsHRZ2 are iron-binding sensors that negatively regulate iron acquisition under conditions of iron sufficiency. PMID:24253678

Extracting phosphoric iron under laboratorial conditions smelting bog iron ores

International Nuclear Information System (INIS)

Török, B; Thiele, A

2013-01-01

In recent years it has been indicated by archaeometric investigations that phosphoric-iron (P-iron, low carbon steel with 0,5-1,5wt% P), which is an unknown and unused kind of steel in the modern industry, was widely used in different parts of the world in medieval times. In this study we try to explore the role of phosphorus in the arhaeometallurgy of iron and answer some questions regarding the smelting bog iron ores with high P-content. XRF analyses were performed on bog iron ores collected in Somogy county. Smelting experiments were carried out on bog iron ores using a laboratory model built on the basis of previously conducted reconstructed smelting experiments in copies of excavated furnaces. The effect of technological parameters on P-content of the resulted iron bloom was studied. OM and SEM-EDS analyses were carried out on the extracted iron and slag samples. On the basis of the material analyses it can be stated that P-iron is usually extracted but the P-content is highly affected by technological parameters. Typical microstructures of P-iron and of slag could also be identified. It could also be established that arsenic usually solved in high content in iron as well

Iron Therapy in Patients with Heart Failure and Iron Deficiency: Review of Iron Preparations for Practitioners.

Science.gov (United States)

Drozd, Marcin; Jankowska, Ewa A; Banasiak, Waldemar; Ponikowski, Piotr

2017-06-01

In patients with heart failure (HF), iron deficiency (ID) correlates with decreased exercise capacity and poor health-related quality of life, and predicts worse outcomes. Both absolute (depleted iron stores) and functional (where iron is unavailable for dedicated tissues) ID can be easily evaluated in patients with HF using standard laboratory tests (assessment of serum ferritin and transferrin saturation). Intravenous iron therapy in iron-deficient patients with HF and reduced ejection fraction has been shown to alleviate HF symptoms and improve exercise capacity and quality of life. In this paper, we provide information on how to diagnose ID in HF. Further we discuss pros and cons of different iron preparations and discuss the results of major trials implementing iron supplementation in HF patients, in order to provide practical guidance for clinicians on how to manage ID in patients with HF.

Siderophore-mediated iron trafficking in humans is regulated by iron

Science.gov (United States)

Liu, Zhuoming; Lanford, Robert; Mueller, Sebastian; Gerhard, Glenn S.; Luscieti, Sara; Sanchez, Mayka; Devireddy, L.

2013-01-01

Siderophores are best known as small iron binding molecules that facilitate microbial iron transport. In our previous study we identified a siderophore-like molecule in mammalian cells and found that its biogenesis is evolutionarily conserved. A member of the short chain dehydrogenase family of reductases, 3-OH butyrate dehydrogenase (BDH2) catalyzes a rate-limiting step in the biogenesis of the mammalian siderophore. We have shown that depletion of the mammalian siderophore by inhibiting expression of bdh2 results in abnormal accumulation of cellular iron and mitochondrial iron deficiency. These observations suggest that the mammalian siderophore is a critical regulator of cellular iron homeostasis and facilitates mitochondrial iron import. By utilizing bioinformatics, we identified an iron-responsive element (IRE; a stem-loop structure that regulates genes expression post-transcriptionally upon binding to iron regulatory proteins or IRPs) in the 3′-untranslated region (3′-UTR) of the human BDH2 (hBDH2) gene. In cultured cells as well as in patient samples we now demonstrate that the IRE confers iron-dependent regulation on hBDH2 and binds IRPs in RNA electrophoretic mobility shift assays. In addition, we show that the hBDH2 IRE associates with IRPs in cells and that abrogation of IRPs by RNAi eliminates the iron-dependent regulation of hBDH2 mRNA. The key physiologic implication is that iron-mediated post-transcriptional regulation of hBDH2 controls mitochondrial iron homeostasis in human cells. These observations provide a new and an unanticipated mechanism by which iron regulates its intracellular trafficking. PMID:22527885

SYNTHESIS AND STUDY OF ANTIOXIDANT ACTIVITY OF [(1-ARYL-5-FORMYL-1H-IMIDAZOLE-4-ILTHIO]PROPIONIC ACIDS

Directory of Open Access Journals (Sweden)

A. O. Palamar

2014-12-01

Full Text Available Introduction. Derivatives of imidazole belong to the promising group of compounds for antioxidant activity study, due to the series of recent publications. This is defined by special features of their structure, specific reactivity and significant potential of pharmacological action. Earlier during process of looking for new antioxidants we studied significant amount of imidazole derivatives, among which the [(1-aryl-5-formylimidazole-4-ilthio]acetic acids structurally modified by the formyl group and thioacetic acid fragment, are especially worth noting. The purpose of the study. Synthesis of [(1-aryl-5-formylimidazole-4-ilthio]propionic acids and comparison of their antioxidant effect with [(1-aryl-5-formylimidazole-4-ilthio]acetic acids with to identify prospects of in-depth study of the most active compounds as antioxidants. Materials and methods. The method based on interaction of available 4-chloro-5-formylimidazoles with thiopropionic acid was proposed for the synthesis of [(1-aryl-5-formylimidazole-4-ilthio]propionic acids. The reaction takes place in ethanol in presence of potassium hydroxide and leads to the target compounds with yields of 81-86%. The study of antioxidant activity of synthesized compounds was conducted in vitro by speed inhibition value of rats’ liver endogenous lipids ascorbate-dependent peroxide oxidation. It was determined by concentration of one of the final products of free radical oxidation of lipids (FROL – maleic aldehyde (MA in the investigated sample. Concentrations of synthesized compounds were chosen within concentrations which were studied for thiotriazolin (manufactured by corporation “Arterium”, Ukraine, solution for injection, 25 mg/ml. The results of the study and their discussion. Preparative method for the synthesis of [(1-aryl-5-formylimidazole-4-ilthio]propionic acids has been designed. Imidazolylthiopropionic acids have been synthesized; they are crystalline compounds, of light

New insights into iron deficiency and iron deficiency anemia.

Science.gov (United States)

Camaschella, Clara

2017-07-01

Recent advances in iron metabolism have stimulated new interest in iron deficiency (ID) and its anemia (IDA), common conditions worldwide. Absolute ID/IDA, i.e. the decrease of total body iron, is easily diagnosed based on decreased levels of serum ferritin and transferrin saturation. Relative lack of iron in specific organs/tissues, and IDA in the context of inflammatory disorders, are diagnosed based on arbitrary cut offs of ferritin and transferrin saturation and/or marker combination (as the soluble transferrin receptor/ferritin index) in an appropriate clinical context. Most ID patients are candidate to traditional treatment with oral iron salts, while high hepcidin levels block their absorption in inflammatory disorders. New iron preparations and new treatment modalities are available: high-dose intravenous iron compounds are becoming popular and indications to their use are increasing, although long-term side effects remain to be evaluated. Copyright © 2017 Elsevier Ltd. All rights reserved.

Iron absorption studies

International Nuclear Information System (INIS)

Ekenved, G.

1976-01-01

The main objective of the present work was to study iron absorption from different iron preparations in different types of subjects and under varying therapeutic conditions. The studies were performed with different radioiron isotope techniques and with a serum iron technique. The preparations used were solutions of ferrous sulphate and rapidly-disintegrating tablets containing ferrous sulphate, ferrous fumarate and ferrous carbonate and a slow-release ferrous sulphate tablet of an insoluble matrix type (Duroferon Durules). The serum iron method was evaluated and good correlation was found between the serum iron response and the total amount of iron absorbed after an oral dose of iron given in solution or in tablet form. New technique for studying the in-vivo release properties of tablets was presented. Iron tablets labelled with a radio-isotope were given to healthy subjects. The decline of the radioactivity in the tablets was followed by a profile scanning technique applied to different types of iron tablets. The release of iron from the two types of tablets was shown to be slower in vivo than in vitro. It was found that co-administration of antacids and iron tablets led to a marked reduction in the iron absorption and that these drugs should not be administered sumultaneously. A standardized meal markedly decreased the absorbability of iron from iron tablets. The influence of the meal was more marked with rapidly-disintegrating than with slow-release ferrous sulphate tablets. The absorption from rapidly-disintegrating and slow-release ferrous sulphate tablets was compared under practical clinical conditions during an extended treatment period. The studies were performed in healthy subjects, blood donors and patients with iron deficiency anaemia and it was found that the absorption of iron from the slow-release tablets was significantly better than from the rapidly-disintegrating tablets in all three groups of subjects. (author)