Sample records for adamantane

  1. 70th Anniversary of the First Synthesis of Adamantane

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    Škorić, I.


    Full Text Available As part of the celebration of the International Year of Chemistry - 2011, the 70th anniversary of the first adamantane synthesis was marked in Zagreb. This article addresses the retrospect of the synthesis of adamantane by Prelog, as well as presents a review of the research in adamantane chemistry in Zagreb from 1971 to the present day. Some research results of the application of the adamantane molecule in other systems were also described, e.g. adamantane crown ethers, dipyrromethanes and bisureas, as well as photochemistry of adamantylphthalimides and photochemical preparation of adamantane quinone methides.

  2. Radiation-chemical alkylation of olefines with adamantane

    International Nuclear Information System (INIS)

    Podkhalyuzin, A.T.; Vikulin, V.V.; Morozov, V.A.; Nazarova, M.P.; Vereshchinskii, I.V.


    Radiation-chemical alkylation of C 2 to C 4 olefines with adamantane was studied in gas phase at temperatures 270 to 430 0 C. The main reaction product is monoalkyladamantane. The reaction proceeds by a free radical chain mechanism. The effective activation energy is of the order of 8 to 10 kcal/mole. Thermal alkylation was carried out for comparison and the contribution of the thermal component to the radiation-thermal process was estimated. Liquid phase alkylation of hexafluoropropylene with adamantane was studied in the presence of solvents. Under various conditions mono- and di-substituted adamantanes are produced containing fluorine in end groups. These compounds were converted to corresponding fluoroalkenyladamantanes by dehydrofluorination. The kinetic parameters were calculated and physical-chemical data concerning some of the resulting products were determined. (author)

  3. Genetic relation of adamantanes from extracts and semicoking tars of lignites with the initial biological material

    Energy Technology Data Exchange (ETDEWEB)

    Platonov, V.V.; Shvykin, A.Y.; Proskuryakov, V.A.; Podshibyakin, S.I. [Lev Tolstoi State Pedagogical University, Tula (Russian Federation)


    A genetic relation was revealed of adamantanes from extracts and semicoking tars of lignites with the relic terpenoid and steroid compounds. Probable pathways are suggested for transformation of the initial natural structures into adamantanes. The qualitative and quantitative compositions of adamantanes from crude oil and coal are compared.

  4. Structure of N'-(adamantan-2-ylidene) benzohydrazide, a potential ...

    Indian Academy of Sciences (India)

    ... a potential antibacterial agent, in solution: Molecular dynamics simulations, quantum chemical calculations and Ultraviolet–visible spectroscopy studies ... N '-(adamantan-2-ylidene)benzohydrazide; UV-Vis spectrum; molecular dynamics simulations; DFT calculations; multi-reference perturbation theory calculations; ...

  5. Solubilities of adamantane and diamantane in pressurized hot water

    Czech Academy of Sciences Publication Activity Database

    Karásek, Pavel; Planeta, Josef; Roth, Michal


    Roč. 53, č. 2 (2008), s. 816-819 ISSN 0021-9568 R&D Projects: GA ČR GA203/07/0886; GA ČR GA203/08/1465; GA ČR GA203/08/1536 Institutional research plan: CEZ:AV0Z40310501 Keywords : aqueous solubility * adamantane * diamantane Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.063, year: 2008

  6. Adamantan, ugradbena jedinica u makrocikličkim sustavima

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    Vujasinović, I.


    Full Text Available Part of our investigation was directed to the synthesis of novel macrocyclic polyethers, which contain polycyclic cage molecule, incorporated into the macrocyclic framework or attached as a side chain. We have prepared a series of adamantane-functionalized oxa-, aza- and thia-crown ethers, and studied their complexation abilities by alkali or transition metal picrate extraction experiments or by electrospray ionization mass spectrometry. In the homogeneous methanol/chloroform solutions as well as, in the extractions of metals from aqueous solution by macrocycles in chloroform, it was found that the type of heteroatom (O, N, S and presence the adamantanesubstituents, influence the metal selectivity as well as the overall lipophilicity of the macrocyclic ligand.

  7. Structure of radicals produced by γ radiolysis. Part 4. Adamantane matrices doped with various 5-membered heterocyclic molecules

    International Nuclear Information System (INIS)

    Winters, D.L.; Ling, A.C.


    The effects of γ-radiolysis at room temperature on adamantane and adamantane-d 16 matrices doped with 5-membered heterocyclic molecules has been examined by X-band electron spin resonance (esr) spectrometry. Radical structures formed from heterocyclic solute molecules are discussed and tentative assignments made. Discussion of possible radical structures derived from selected heterocyclic compounds is included, but unambiguous assignmens of structure cannot be made for these compounds from the esr data obtained. It was noted that perdeuterated adamantane matrices provided superior resolution for esr spectra derived from radicals with a delocalized spin center such as allyl or allenyl species. (author)

  8. Using crystal structure prediction to rationalize the hydration propensities of substituted adamantane hydrochloride salts. (United States)

    Mohamed, Sharmarke; Karothu, Durga Prasad; Naumov, Panče


    The crystal energy landscapes of the salts of two rigid pharmaceutically active molecules reveal that the experimental structure of amantadine hydrochloride is the most stable structure with the majority of low-energy structures adopting a chain hydrogen-bond motif and packings that do not have solvent accessible voids. By contrast, memantine hydrochloride which differs in the substitution of two methyl groups on the adamantane ring has a crystal energy landscape where all structures within 10 kJ mol(-1) of the global minimum have solvent-accessible voids ranging from 3 to 14% of the unit-cell volume including the lattice energy minimum that was calculated after removing water from the hydrated memantine hydrochloride salt structure. The success in using crystal structure prediction (CSP) to rationalize the different hydration propensities of these substituted adamantane hydrochloride salts allowed us to extend the model to predict under blind test conditions the experimental crystal structures of the previously uncharacterized 1-(methylamino)adamantane base and its corresponding hydrochloride salt. Although the crystal structure of 1-(methylamino)adamantane was correctly predicted as the second ranked structure on the static lattice energy landscape, the crystallization of a Z' = 3 structure of 1-(methylamino)adamantane hydrochloride reveals the limits of applying CSP when the contents of the crystallographic asymmetric unit are unknown.

  9. Synthesis, structural and vibrational properties of 1-(adamantane-1-carbonyl)-3-halophenyl thioureas (United States)

    Saeed, Aamer; Erben, Mauricio F.; Bolte, Michael


    1-(Adamantane-1-carbonyl)-3-(2,4-dichlorophenyl)thiourea (1) and 1-(adamantane-1-carbonyl)-3-(2-bromo-4,6-difluorophenyl)thiourea (2) were synthesized by the reaction of adamantane-1-carbonyl chloride with ammonium thiocyanate to afford the adamantane-1-carbonylisothiocyanate in situ followed by treatment with suitable halogenated anilines. The structures of the products were established by elemental analyses, Fourier transform infrared spectroscopy (FTIR), 1H, 13C nuclear magnetic resonance (NMR), mass spectroscopy and single crystal X-ray diffraction study. Bond lengths and angles show the usual values. All of three condensed cyclohexane rings of the adamantane residues adopt the usual chair conformation. The molecular conformation of 1 and 2 is stabilized by an intramolecular (Nsbnd H⋯Odbnd C) hydrogen bond which forms a pseudo-six-membered ring. Structural features have been complemented with the joint analysis of the FTIR and FT-Raman spectra along with quantum chemical calculations at the B3LYP/6-311++G** level.

  10. Novel adamantane-bearing anilines and properties of their supramolecular complexes with b-cyclodextrin

    Czech Academy of Sciences Publication Activity Database

    Vícha, R.; Rouchal, M.; Kozubková, Z.; Kuřitka, I.; Marek, R.; Branná, P.; Čmelík, Richard


    Roč. 23, č. 10 (2011), s. 663-677 ISSN 1061-0278 Institutional research plan: CEZ:AV0Z40310501 Keywords : adamantane * cyclodextrin s * host–guest systems Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.145, year: 2011

  11. The Vacancy Formation Energy in Crystalline Adamantane Determined by Positron Annihilation Techniques

    DEFF Research Database (Denmark)

    Lightbody, D.; Sherwood, J. N.; Eldrup, Morten Mostgaard


    The injection of positrons into crystalline adamantane results in the formation of positronium (Ps). At temperatures T> 400 K the mean lifetime of the long-lived ortho-positronium exhibits a sigmoidal increase with temperature characteristic of the trapping of this species in thermally created de...

  12. Calculation of dipole polarizability derivatives of adamantane and their use in electron scattering computations

    DEFF Research Database (Denmark)

    Sauer, Stephan P. A.; Paidarová, Ivana; Čársky, Petr


    that the polarizability tensor is necessary to correct long-range behavior of DFT functionals used in electron-molecule scattering calculations. The impact of such a long-range correction is demonstrated on elastic and vibrationally inelastic electron collisions with adamantane, a molecule representing a large polyatomic...

  13. Adamantane-based amphiphiles (ADAs) for membrane protein study: importance of a detergent hydrophobic group in membrane protein solubilisation. (United States)

    Chae, Pil Seok; Bae, Hyoung Eun; Das, Manabendra


    We prepared adamantane-containing amphiphiles and evaluated them using a large membrane protein complex in terms of protein solubilisation and stabilization efficacy. These agents were superior to conventional detergents, especially in terms of the membrane protein solubilisation efficiency, implying a new detergent structure-property relationship.

  14. Reaction or organomagnesium compounds of the adamantane series with carbonyl compounds

    International Nuclear Information System (INIS)

    Yurchenko, A.G.; Fedorenko, T.V.


    In the transformations of organomagnesium compounds of the adamantane series involving aldehydes, ketones, esters, and acid chlorides the nature of the reaction products and their yields are determined by the steric hindrances at the reaction centers of the organomagnesium and carbonyl compounds and by the ease of homolysis of the C-H bonds of the carbonyl reagent. The retardation of the faster addition of the Grignard reagent at the carbonyl group as a result of steric hindrances permits homolytic removal of a hydrogen atom from the carbonyl compound by the adamantyl radical. The PMR spectra were measured on a Tesla BS-487C spectrometer at 80 MHz in carbon tetrachloride with the substances at concentrations of 5-20% and with TMS as internal standard. The IR spectra were obtained in carbon tetrachloride on a UR-10 spectrophotometer

  15. Adamantane-bearing benzylamines and benzylamides: novel building blocks for supramolecular systems with finely tuned binding properties towards β-cyclodextrin

    Czech Academy of Sciences Publication Activity Database

    Rouchal, M.; Matelová, A.; de Carvalho, F. P.; Bernat, R.; Grbić, D.; Kuřitka, I.; Babinský, M.; Marek, R.; Čmelík, Richard; Vícha, R.


    Roč. 25, č. 6 (2013), s. 349-361 ISSN 1061-0278 Institutional support: RVO:68081715 Keywords : host-guest system * cyclodextrin s * adamantane Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.132, year: 2013

  16. Adamantane-bearing benzylamines and benzylamides: novel building blocks for supramolecular systems with finely tuned binding properties towards β-cyclodextrin

    Czech Academy of Sciences Publication Activity Database

    Rouchal, M.; Matelová, A.; de Carvalho, F. P.; Bernat, R.; Grbić, D.; Kuřitka, I.; Babinský, M.; Marek, R.; Čmelík, Richard; Vícha, R.


    Roč. 25, č. 6 (2013), s. 349-361 ISSN 1061-0278 Institutional support: RVO:68081715 Keywords : host-guest system * cyclodextrins * adamantane Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.132, year: 2013

  17. Adamantane and Neuraminidase resistant influenza A/H3N2 isolated in Iran from 2005 to 2013

    Directory of Open Access Journals (Sweden)

    Jila Yavarian


    Conclusion: This study showed circulating A/H3N2 viruses was resistant to adaman-tanes but susceptible to neuraminidase inhibitors. The national data analyzed in this re-search may help increase knowledge about influenza virus antiviral drug resistance, which is a global public health concern. The authors suggested continuing this study and also the investigation of antiviral drug resistance of influenza A/H1N1 and B viruses.

  18. EPR and optical spectroscopic studies of neutral free radicals in an adamantane matrix

    International Nuclear Information System (INIS)

    Jordan, J.E.


    Recent work in our laboratory has demonstrated that neutral free radicals produced by x-irradiation and trapped in adamantane exhibit exceedingly long lifetimes because of the lack of rapid diffusion in the solid matrix. This observation and the fact that samples can be pressed into pellets with high optical transparency in the visible and near uv regions of the spectrum suggested to us that this unique matrix might be used for studying the optical properties of free radicals. The results of a wide variety of experiments of this type are described in this thesis. These include experiments in which secondary free radicals are produced by photoinduced decomposition of primary free radicals by selective irradiation with visible light, the observation of strong optical absorption spectra of free radicals at room temperature using a Cary 14 spectrophotometer, the finding that certain free radicals exhibit strong, visible fluorescence when irradiated with uv light, and the discovery that the absorption intensity of multiplicity-forbidden transition in singlet and doublet state species is enhanced relative to spin-allowed transitions by at least three orders of magnitude. An analysis of these results in terms of molecular orbital theory is given, and experiments designed to obtain the epr spectra of electronically-excited states of free radicals are described

  19. Synthesis and Electroluminescent Properties of Julolidine-π-Juloidine Type Materials with the Bulky Adamantane Groups

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kum Hee; Yoon, Seung Soo [Sungkyunkwan Univ., Suwon (Korea, Republic of); Lee, Seok Jae; Kim, Young Kwan [Hongik Univ., Seoul (Korea, Republic of)


    A main problem of red emitting material, which contributes to their low EL performances, is the concentration quenching due to the effective self aggregation and the consequent formation of excimers. To avoid this drawback and thus improve the EL properties of red fluorescent OLED devices, many synthetic efforts have been conducted to develop new emitting materials with the structural motifs to suppress self-aggregation by the weakening intermolecular attractive interactions. Particularly, the introduction of bulky moieties in the emitters would provide the steric hindrance between emitting materials in solid state devices and thus reduce the self-aggregation. Nevertheless, EL performances of red materials still need to be improved for the practical applications. In conclusion, we designed and synthesized three julolidine-π-juloidine type emitting materials (1-3) with the bulky adamantane groups. To study their electroluminescent properties, the multilayered OLED devices with the structure of ITO/NPB (40 nm)/ADN : 1-3 (x%) (20 nm)/Alq{sub 3} (40 nm)/Liq (2 nm)/Al were fabricated. All devices using emitters 1-3 showed the efficient emissions, in which their EL performances depend on the structure of emitters sensitively. Particularly, a device using emitter 3 exhibited the efficient orange-red emission with the luminous and power efficiencies of 4.79 cd/A and 1.76 lm/W at 20 mA/cm{sup 2}, respectively. The CIE coordinates of this device was (0.57, 0.42) at 7.0 V.

  20. Control the wettability of poly(n-isopropylacrylamide-co-1-adamantan-1-ylmethyl acrylate) modified surfaces: the more Ada, the bigger impact? (United States)

    Shi, Xiu-Juan; Chen, Gao-Jian; Wang, Yan-Wei; Yuan, Lin; Zhang, Qiang; Haddleton, David M; Chen, Hong


    Surface-initiated SET-LRP was used to synthesize polymer brush containing N-isopropylacrylamide and adamantyl acrylate using Cu(I)Cl/Me6-TREN as precursor catalyst and isopropanol/H2O as solvent. Different reaction conditions were explored to investigate the influence of different parameters (reaction time, catalyst concentration, monomer concentration) on the polymerization. Copolymers with variable 1-adamantan-1-ylmethyl acrylate (Ada) content and comparable thickness were synthesized onto silicon surfaces. Furthermore, the hydrophilic and bioactive molecule β-cyclodextrin-(mannose)7 (CDm) was synthesized and complexed with adamantane via host-guest interaction. The effect of adamantane alone and the effect of CDm together with adamantane on the wettability and thermoresponsive property of surface were investigated in detail. Experimental and molecular structure analysis showed that Ada at certain content together with CDm has the greatest impact on surface wettability. When Ada content was high (20%), copolymer-CDm surfaces showed almost no CDm complexed with Ada as the result of steric hindrance.


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    V. M. Odyntsova


    Full Text Available The concentration of glucose in the blood is one of the integral indicators of the internal environment that reflects the metabolism of carbohydrates, proteins and fats in the body. Glucose is a key component of human metabolism. The level of blood sugar is one of the most important controlled constants of body that defines homeostasis and displays the status of carbohydrate metabolism. Low blood sugar (hypoglycemia is a dangerous condition when blood glucose is critically low. The aim of research. The aim of our study was pharmacological screening of the effects of the newly synthesized salts of 2-(5-adamantane-1-yl-4-R-1,2,4-tirazol-3-yltioacetic acids on glucose blood level in experimental animals. Materials and methods. The compounds have been synthesized at the Department of Inorganic Chemistry and Toxicology of Zaporozhye State Medical University (the Head of the chair, Professor Panasenko O.I.. Blood glucose levels of saults of2-(5-adamantane-1-yl-4-R-1,2,4-tirazol-3-yltioacetic acids in rats have been evaluated by intraperitoneal glucose tolerance test (IGTT. IGTT was reproduced by glucose load on animals in a dose of 2 g / kg of rat’s body weight. White nonlinear rats weighing 160-230 g were involved in experiments. Animals were divided into 13 groups of 7 animals in each group: the 1st is intact one; the 2nd is control one with glycemia (untreated, the 3rd group of the animals received glibenclamide in the dose of 1 mg / kg; the groups 3-13 received 1,2,4-triazole derivatives. The compounds were dissolved in purified water at the rate of 1 ml per 100 g of animals’ weight and were injected intraperitoneally. Glucose content in blood has been measured by glucosidase method using glucometer «Accu Chek Active» in 30 minutes from the load moment. The research results have been processed by modern statistical methods of analysis on a personal computer using a standard software package Microsoft Office 2010 (Microsoft Excel and

  2. Controlled gelation kinetics of cucurbit[7]uril-adamantane cross-linked supramolecular hydrogels with competing guest molecules (United States)

    Chen, Hao; Hou, Shengzhen; Ma, Haili; Li, Xu; Tan, Yebang


    Gelation kinetics of hydrogels is closely linked to many applications such as the development of injectable and printable hydrogels. However, the control of gelation kinetics without compromising the structure and other properties of the hydrogels, remains a challenge. Here, we demonstrate a method to control the gelation kinetics of cucurbit[7]uril-adamantane (CB[7]-AD) cross-linked supramolecular hydrogels by using competing guest molecules. The association between CB[7] and AD moieties on the polymer backbone was impeded by pre-occupying the CB[7] cavity with competing guest molecules. By using various guest molecules and concentrations, the gelation of the hydrogels could be varied from seconds to hours. The strong interaction of CB[7]-AD pair endue the hydrogels good mechanical properties and stability. Moreover, the binding of functionalized guest molecules of CB[7] moieties offers a facile approach for tailoring of the hydrogels’ scaffold. Combined with hydrogel injection and printing technology, this method offers an approach for the development of hydrogels with advanced temporal and spatial complexity.

  3. Synthesis, physical-chemical properties of 2-((5-(adamantan-1-yl-4-R-4H-1,2,4-triazole-3-ylthioacetic acid esters

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    V. M. Odyntsova


    Full Text Available The nitrogen-containing heterocyclic systems from the class of 1,2,4-triazole derivatives, which exhibit wide range of actions, occupy special place among the variety of heterocyclic compounds. Derived biologically active substances are actively introduced into practice as new original and effective drugs. We were interested in esters of 2-((5-(adamantan-1-yl-4-R-4H-1,2,4-triazole-3-ylthioacetic acids, which exhibit high biological activity and can be intermediates for the synthesis of amides, hydrazides, ylidenderivatives of corresponding acids. The aim of this work is the synthesis of new esters of 2-((5-(adamantan-1-yl-4-R-4H-1,2,4-triazole-3-ylthioacetic acids and the establishment of their physical-chemical properties. Materials and methods. Melting point was determined by open capillary method on the device OptiMelt MPA100. The elemental composition of the synthesized compounds was determined on the universal analyzer ElementarVario ЕL cube (CHNS (standard – sulfanilamide. 1H NMR spectra were recorded on spectrometer Varian Mercury VX-200 (1H, 200 MHz in the solvent dimethyl sulfoxide-d6 (tetramethylsilane internal standard and decoded using a program ADVASP(tm Analyzer program (Umatek International Inc.. Chromato-mass-spectral studies were performed on hazarding chromatograph Agilent 1260 Infinity HPLC equipped with mass spectrometer Agilent 6120 (ionization electro-spray (ESI. The results and discussion. Synthesis of 11 new compounds, namely esters of 2-((5-(adamantan-1-yl-4-R-4H-1,2,4-triazole-3-ylthioacetic acids was carried out by two methods. According to the A method the alkylation of previously synthesized 3-(adamantan-1-yl-1H-1,2,4-triazole-5-thiol was performed with the use of corresponding methyl ester of 2-chloroacetic acid and the presence of equivalent amount of sodium hydroxide. The B method involves the etherification of 2-((5-(adamantan-1-yl-4-R-4H-1,2,4-triazole-3-ylthioacetic acid with the use of methyl, ethyl, i

  4. In depth analysis on the binding sites of adamantane derivatives in HCV (hepatitis C virus p7 channel based on the NMR structure.

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    Qi-Shi Du

    Full Text Available BACKGROUND: The recently solved solution structure of HCV (hepatitis C virus p7 ion channel provides a solid structure basis for drug design against HCV infection. In the p7 channel the ligand amantadine (or rimantadine was determined in a hydrophobic pocket. However the pharmocophore (-NH2 of the ligand was not assigned a specific binding site. RESULTS: The possible binding sites for amino group of adamantane derivatives is studied based on the NMR structure of p7 channel using QM calculation and molecular modeling. In the hydrophobic cavity and nearby three possible binding sites are proposed: His17, Phe20, and Trp21. The ligand binding energies at the three binding sites are studied using high level QM method CCSD(T/6-311+G(d,p and AutoDock calculations, and the interaction details are analyzed. The potential application of the binding sites for rational inhibitor design are discussed. CONCLUSIONS: Some useful viewpoints are concluded as follows. (1 The amino group (-NH2 of adamantane derivatives is protonated (-NH3+, and the positively charged cation may form cation-π interactions with aromatic amino acids. (2 The aromatic amino acids (His17, Phe20, and Trp21 are the possible binding sites for the protonated amino group (-NH3+ of adamantane derivatives, and the cation-π bond energies are 3 to 5 times stronger than the energies of common hydrogen bonds. (3 The higher inhibition potent of rimantadine than amantadine probably because of its higher pKa value (pKa = 10.40 and the higher positive charge in the amino group. The potential application of p7 channel structure for inhibitor design is discussed.

  5. Oxidative alkylation of azoles. 6. Generation of active alkylating agents at oxidation of 1-iodo- and 1-bromo-adamantane by 3-nitro-1-chloro-1,2,4-triazole and chlorine

    International Nuclear Information System (INIS)

    Tsypin, V.G.; Pevzner, M.S.


    Reactions of N-chloro-triazole with iodo-adamantane were carried out in chloroform at 15-20 Deg C with varied excess of iodine-derivative, up to 200 mol. %. 1-chloro-adamantane, 1-iodo-adamantane, adamantanol-1,3-nitro-1,2,4-triazole, 1-(1-adamantyl)-5-nitro-1,2,4-triazole, 1-(1-adamantyl)-3-nitro-1,2,4-triazole, I 2 , ICl and non-identification impurities are discovered in the reaction mass. Dosing of iodo-derivatives in the excess of oxidative gave rise to separation of I 2 , which was then as a reductant in the reaction with N-chloro-triazole. On further dosing of iodo-derivative steady iodine coloring appeared and unsubstituted triazole was the main product of the reaction. It is supposed that using chlorine for oxidation of iodo-derivative trends to formation of unstable intermediate AdICl 2 [ru

  6. Self-healing pH-sensitive poly[(methyl vinyl ether)-alt-(maleic acid)]-based supramolecular hydrogels formed by inclusion complexation between cyclodextrin and adamantane. (United States)

    Ma, Xiaoe; Zhou, Naizhen; Zhang, Tianzhu; Hu, Wanjun; Gu, Ning


    Self-healing materials are of interest for drug delivery, cell and gene therapy, tissue engineering, and other biomedical applications. In this work, on the base of biocompatible polymer poly(methyl vinyl ether-alt-maleic acid) (P(MVE-alt-MA)), host polymer β-cyclodextrin-grafted P(MVE-alt-MA) (P(MVE-alt-MA)-g-β-CD) and guest polymer adamantane-grafted P(MVE-alt-MA) (P(MVE-alt-MA)-g-Ad) were first prepared. Then through taking advantage of the traditional host-guest interaction of β-cyclodextrin and adamantane, a novel self-healing pH-sensitive physical P(MVE-alt-MA)-g-β-CD/P(MVE-alt-MA)-g-Ad supramolecular hydrogels were obtained after simply mixing the aqueous solution of host polymer and guest polymer. This kind of supramolecular hydrogels not only possess pH-sensitivity, but also possess the ability to repair themselves after being damaged. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Characterization of isolated 1-aza-adamantan-4-one (C9H13NO) from microwave, millimeter-wave and infrared spectroscopy supported by electronic structure calculations (United States)

    Pirali, O.; Goubet, M.; Boudon, V.; D'Accolti, L.; Fusco, C.; Annese, C.


    We have synthesized 1-aza-adamantan-4-one (C9H13NO) starting from commercial 1,4-cyclohexanedionemonoethylene acetal and tosylmethylisocianide, following a procedure already described in the literature. The high degree of sample purity was demonstrated by gas chromatography and mass spectrometric measurements and its structure evidenced by 1H and 13C NMR spectroscopy. Among numerous interests in physical chemistry, this target molecule is of high relevance for mechanistic evaluation and the synthesis of novel pharmaceutical compounds. We present a thorough spectroscopic study of this molecule by gas phase vibrational and rotational spectroscopy. Accurate vibrational frequencies have been determined from infrared and far-infrared spectra. The pure rotational spectrum of the molecule has been recorded both by cavity-based Fourier transform microwave spectroscopy in the 2-20 GHz region by supersonically expanding the vapor pressure of the warm sample and by room-temperature absorption spectroscopy in the 140-220 GHz range. Accurate sets of rotational and centrifugal distortion parameters of 1-aza-adamantan-4-one in its ground state and in five vibrationally excited states have been derived from these measurements and compared to accurate quantum chemical calculations. The hyperfine parameters have been discussed in terms of molecular structure around the nitrogen quadrupole nucleus.

  8. Implanted muon spin spectroscopy on 2-O-adamantane: a model system that mimics the liquid[Formula: see text]glasslike transitions. (United States)

    Romanini, M; Tamarit, J L; Pardo, L C; Bermejo, F J; Fernandez-Perea, R; Pratt, F L


    The transition taking place between two metastable phases in 2-O-adamantane, namely the [Formula: see text] cubic, rotator phase and the lower temperature P2 1 /c, Z  =  4 substitutionally disordered crystal is studied by means of muon spin rotation and relaxation techniques. Measurements carried out under zero, weak transverse and longitudinal fields reveal a temperature dependence of the relaxation parameters strikingly similar to those exhibited by structural glass[Formula: see text]liquid transitions (Bermejo et al 2004 Phys. Rev. B 70 214202; Cabrillo et al 2003 Phys. Rev. B 67 184201). The observed behaviour manifests itself as a square root singularity in the relaxation rates pointing towards some critical temperature which for amorphous systems is located some tens of degrees above that shown as the characteristic transition temperature if studied by thermodynamic means. The implications of such findings in the context of current theoretical approaches concerning the canonical liquid-glass transition are discussed.

  9. 2 : 2 Fe(III): ligand and "adamantane core" 4 : 2 Fe(III): ligand (hydr)oxo complexes of an acyclic ditopic ligand

    DEFF Research Database (Denmark)

    Ghiladi, Morten; Larsen, Frank B.; McKenzie, Christine J.


    crystalline platelets. The Fe4O6 core of 2 shows an adamantane-like structure: The six bridging oxygen atoms are provided by the two phenolato groups of the two bpbp(-) ligands, two bridging oxo groups and two bridging hydroxo groups. The hydroxo and oxo ligands could be distinguished on the basis of Fe - O......-ray structure of the dinuclear complex [{( Hbpbp) Fe(mu-OH)}(2)](ClO4)(4) center dot 2C(3)H(6)O ( 1 center dot 2C(3)H(6)O) shows that only one of the metal-binding cavities of each ligand is occupied by an iron( III) atom and two [Fe(Hbpbp)](3+) units are linked together by two hydroxo bridging groups to form...... a [ Fe(III) -(mu-OH)](2) rhomb structure with Fe center dot center dot center dot Fe = 3.109(1) angstrom. The non-coordinated tertiary amine of Hbpbp is protonated. Magnetic susceptibility measurements show a well-behaved weak antiferromagnetic coupling between the two Fe( III) atoms, J =- 8 cm(-1...

  10. New ultrahigh affinity host-guest complexes of cucurbit[7]uril with bicyclo[2.2.2]octane and adamantane guests: thermodynamic analysis and evaluation of M2 affinity calculations. (United States)

    Moghaddam, Sarvin; Yang, Cheng; Rekharsky, Mikhail; Ko, Young Ho; Kim, Kimoon; Inoue, Yoshihisa; Gilson, Michael K


    A dicationic ferrocene derivative has previously been shown to bind cucurbit[7]uril (CB[7]) in water with ultrahigh affinity (ΔG(o) = -21 kcal/mol). Here, we describe new compounds that bind aqueous CB[7] equally well, validating our prior suggestion that they, too, would be ultrahigh affinity CB[7] guests. The present guests, which are based upon either a bicyclo[2.2.2]octane or adamantane core, have no metal atoms, so these results also confirm that the remarkably high affinities of the ferrocene-based guest need not be attributed to metal-specific interactions. Because we used the M2 method to compute the affinities of several of the new host-guest systems prior to synthesizing them, the present results also provide for the first blinded evaluation of this computational method. The blinded calculations agree reasonably well with experiment and successfully reproduce the observation that the new adamantane-based guests achieve extremely high affinities, despite the fact that they position a cationic substituent at only one electronegative portal of the CB[7] host. However, there are also significant deviations from experiment, and these lead to the correction of a procedural error and an instructive evaluation of the sensitivity of the calculations to physically reasonable variations in molecular energy parameters. The new experimental and computational results presented here bear on the physical mechanisms of molecular recognition, the accuracy of the M2 method, and the usefulness of host-guest systems as test-beds for computational methods.

  11. Synthesis and Solution Properties of Adamantane Containing Quaternary Ammonium Salt-type Cationic Surfactants: Hydrocarbon-based, Fluorocarbonbased and Bola-type. (United States)

    Yoshimura, Tomokazu; Okada, Mari; Matsuoka, Keisuke


    Quaternary ammonium salt-type cationic surfactants with an adamantyl group (hydrocarbon-type; C n AdAB, fluorocarbon-type; C m F C 3 AdAB, bola-type; Ad-s-Ad, where n, m and s represent hydrocarbon chain lengths of 8-16, fluorocarbon chain lengths of 4-8, and spacer chain length of 10-12) were synthesized via quaternization of N, N-dimethylaminoadamantane and n-alkyl bromide or 1, n-dibromoalkane. Conductivity and surface tension were measured to characterize the solution properties of the synthesized adamantyl group-containing cationic surfactants. In addition, the effects of hydrocarbon and fluorocarbon chain lengths and spacer chain length between headgroups on the measured properties were evaluated by comparison with those of conventional cationic surfactants. The critical micelle concentration (CMC) of C n AdAB and Ad-s-Ad was 2/5 of that for the corresponding conventional surfactants C n TAB and bola-type surfactants with similar number of carbons in the alkyl or alkylene chain; this was because of the increased hydrophobicity due to the adamantyl group. A linear relationship between the logarithm of CMC and the hydrocarbon chain length for C n AdAB was observed, as well as for C n TAB. The slope of the linear correlation for both surfactants was almost the same, indicating that the adamantyl group does not affect the CMC with variations in the hydrocarbon chain length. Similar to conventional surfactants C n TAB, the hydrocarbon-type C n AdAB is highly efficient in reducing the surface tension of water, despite the large occupied area per molecule resulting from the relatively bulky structure of the adamantane skeleton. On the other hand, the bola-type Ad-s-Ad resulted in increased surface tension compared to C n AdAB, indicating that the curved chain between adamantyl groups leads to poor adsorption and orientation at the air-water interface.

  12. Synthesis, physical and chemical properties, antihypoxic activity of some 5-[((5-(adamantane-1-yl-4-R-4H-1,2,4-triazole-3-ylthiomethyl]-N-R1-1,3,4-thiadiazole-2-amines and 5-[((5-(adamantane-1-yl-4-R-4H-1,2,4-triazole-3-ylthiomethyl]-4-R1-4H-1,2,4-t

    Directory of Open Access Journals (Sweden)

    V. M. Odyntsova


    Full Text Available Today, an increase of natural and technogenic situations leads to the disorders of the central nervous system, functional-metabolic processes, vascular diseases, in particular, acute cerebral blood flow disorders. In addition, the changes occurring on the molecular and cellular levels are in the basis of the functional violations of individual systems and the organism as a whole. Hypoxia not only complicates the disease course, but in most cases, determines its outcome. The important role in the fight against hypoxia belongs to antioxidants, which improve the circulating oxygen utilization by the body, reduce its need for the organs and tissues, which is not only expedient but necessary for the treatment of many acute and chronic pathological processes. So, the frequency of the hypoxic states and a wide range of factors causing them determine the relevance of new ways and methods finding to overcome the oxygen deficiency. The aim of this work is the purposeful search of some 5-[((5-(adamantane-1-yl-4-R-4H-1,2,4-triazole-3-ylthiomethyl]-N-R1-1,3,4-thiadiazole-2-amines and 5-[((5-(adamantane-1-yl-4-R-4H-1,2,4-triazole-3-ylthiomethyl]-4-R1-4H-1,2,4-triazole-3-thiols, the study of their physical and chemical properties and pharmacological screening of the antihypoxic activity of the obtained compounds. Materials and methods. The study of physical and chemical properties was conducted on certified and licensed modern equipment. Antihypoxic activity was studied during the modeling process of hypoxia with hypercapnia. Mexidol was used as a comparison drug in studies at a dose of 100 mg/kg. Results. As the result of the study, it was found that the synthesized compounds and the comparison drug influenced on rats’ life span differently. Compounds, the antihypoxic activity of which exceeded control have been discovered, and others’ were at the level of Mexidol. A number of compounds showed a somewhat less activity in comparison with control, and two

  13. Surveillance of adamantane resistance among influenza A H3 viruses isolated in Argentina between 2001 and 2007 Vigilancia de la resistencia a los adamantanos entre los virus influenza A H3 aislados en Argentina entre 2001 y 2007

    Directory of Open Access Journals (Sweden)

    A. Pontoriero


    Full Text Available A dramatic rise in the frequency of resistance to adamantane drugs by influenza A H3 viruses, associated with a single amino acid replacement in the viral matrix M2 protein, has occurred in multiple countries worldwide in recent years. We investigated the frequency of adamantane-resistant influenza A H3 viruses in Argentina during the period 2001- 2007. We used reverse transcription followed by polymerase chain reaction. The obtained products were sequenced for the detection of mutations of the M2 gene relevant to the resistance phenotypes. The HA1 sequences of the sensitive and resistant strains were also analyzed to clarify whether they had any relevance to the resistant mutations. Twenty out of 55 (36% strains were identified with the resistance-conferring substitution at amino acid 31 (Serine 31 Asparagine. No resistant viruses were detected between 2001 and 2005. All strains isolated in 2006 and four out of five isolates from 2007 were resistant. None of the patients had received previous treatment with amantadine and/or rimantadine. The HA1 analysis showed that there were only two changes (Serine193 Phenylalanine and Aspartic acid 225 Asparagine present in the strains with the M2 substitution at position 31. Our data indicate that since 2006 there has been a significant increase of adamantane-resistant influenza A H3 viruses, which raises concern over the spread of these viruses in Argentina.En los últimos años, se ha detectado un aumento de virus influenza A H3 resistentes a los adamantanos en distintos países, asociados mayoritariamente con el reemplazo de un único aminoácido de la proteína matriz M2. Se investigó la frecuencia de virus influenza A H3 resistentes a los adamantanos en Argentina entre 2001 y 2007. Se utilizó la transcripción reversa seguida de la reacción en cadena de la polimerasa y de la técnica de secuencia directa para la detección de mutaciones en el gen que codifica para la proteína M2, relevantes para

  14. Electrophysiological study, biodistribution in mice, and preliminary PET evaluation in a rhesus monkey of 1-amino-3-[18F]fluoromethyl-5-methyl-adamantane (18F-MEM): a potential radioligand for mapping the NMDA-receptor complex. (United States)

    Samnick, S; Ametamey, S; Leenders, K L; Vontobel, P; Quack, G; Parsons, C G; Neu, H; Schubiger, P A


    The effect of the fluorinated memantine derivative and NMDA receptor antagonist, 1-amino-3-fluoromethyl-5-methyl-adamantane (19F-MEM), at the NMDA receptor ion channel was studied by patch clamp recording. The results showed that 19F-MEM is a moderate NMDA receptor channel blocker. A procedure for the routine preparation of the 18F-labelled analog 18F-MEM has been developed using a two-step reaction sequence. This involves the no-carrier-added nucleophilic radiofluorination of 1-[N-(tert-butyloxy)carbamoyl]-3-(toluenesulfonyloxy)methyl- 5-methyl-adamantane and the subsequent cleavage of the BOC-protecting group using aqueous HCI. The 18F-MEM was obtained in 22 +/- 7% radiochemical yield (decay-corrected to EOB) in a total synthesis time including HPLC purification of 90 min. A biodistribution study after i.v. injection of 18F-MEM in mice showed a fast clearance of radioactivity from blood and relatively high initial uptake in the kidney and in the lung, which gradually decreased with time. The brain uptake was high (up to 3.6% ID/g, 60 min postinjection) with increasing brain-blood ratios: 2.40, 5.10, 6.33, and 9.27 at 5, 30, 60, and 120 min, respectively. The regional accumulation of the radioactivity in the mouse brain was consistent with the known distribution of the PCP recognition site. Preliminary PET evaluation of the radiotracer in a rhesus monkey demonstrated good uptake and prolonged retention in the brain, with a plateau from 35 min onwards p.i. in the NMDA receptor-rich regions (frontal cortex, striata, and temporal cortex). Delineation of the hippocampus, a region known to contain a high density of NMDA receptors, was not possible owing to the resolution of the PET tomograph. The regional brain uptake of 18F-MEM was changed by memantine and by a pharmacological dose of (+)-MK-801, indicating competition for the same binding sites. In a preliminary experiment, haloperidol, a dopamine D2 and sigma receptor antagonist, decreased the binding of 18F

  15. Structural and spectroscopic characterization of a novel potential anti-inflammatory agent 3-(adamantan-1-yl)-4-ethyl-1H-1,2,4-triazole-5(4H)thione by first principle calculations. (United States)

    Al-Tamimi, Abdul-Malek S; El-Emam, Ali A; Al-Deeb, Omar A; Prasad, Onkar; Pathak, Shilendra K; Srivastava, Ruchi; Sinha, Leena


    A comprehensive investigation on the molecular structure, electronic properties and vibrational spectra of the 3-(adamantan-1-yl)-4-ethyl-1H-1,2,4-triazole-5(4H)thione, a novel potential anti-inflammatory agent has been done with the hope that the results of present study may be helpful in the prediction of its mechanism of biological activity. The experimentally observed spectral data (FT-IR and FT-Raman) of the title compound was compared with the spectral data obtained by DFT/B3LYP method. The (1)H nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by the Gauge Including Atomic Orbital method and compared with experimental results. The molecular properties like dipole moment, polarizability, first static hyperpolarizability, the molecular electrostatic potential surface, contour map have been calculated to get a better insight of the properties of the title molecule. Natural bond orbital (NBO) analysis has been applied to study stability of the molecule arising from charge delocalization. UV-Vis spectrum of the title compound was also recorded and the electronic properties, such as Frontier orbitals and band gap energies were calculated by TD-DFT approach. Global and local reactivity descriptors have been computed to predict reactivity and reactive sites on the molecule. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Calculation of dipole polarizability derivatives of adamantane and their use in electron scattering computations

    Czech Academy of Sciences Publication Activity Database

    Sauer, S. P. A.; Paidarová, Ivana; Čársky, Petr; Čurík, Roman


    Roč. 70, č. 5 (2016), č. článku 105. ISSN 1434-6060 R&D Projects: GA MŠk LD14088 Grant - others:COST(XE) CM1301 Institutional support: RVO:61388955 Keywords : DENSITY-FUNCTIONAL-THEORY * COUPLED-CLUSTER CALCULATIONS * FREQUENCY-DEPENDENT POLARIZABILITIES Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.288, year: 2016

  17. Crystal structure of 2-(adamantan-1-yl-5-(4-bromophenyl-1,3,4-oxadiazole

    Directory of Open Access Journals (Sweden)

    Nourah Z. Alzoman


    Full Text Available In the title molecule, C18H19BrN2O, the benzene ring is inclined to the oxadiazole ring by 10.44 (8°. In the crystal, C—H...π interactions link the molecules in a head-to-tail fashion, forming chains extending along the c-axis direction. The chains are further connected by π–π stacking interactions, with centroid–centroid distances of 3.6385 (7 Å, forming layers parallel to the bc plane.

  18. Adamantane substitutions: a path to high-performing, soluble, versatile and sustainable organic semiconducting materials

    Czech Academy of Sciences Publication Activity Database

    Kovalenko, A.; Yumusak, C.; Heinrichová, P.; Stříteský, S.; Fekete, Ladislav; Vala, M.; Weiter, M.; Sariciftci, N. S.; Krajčovič, J.


    Roč. 5, č. 19 (2017), s. 4716-4723 ISSN 2050-7526 R&D Projects: GA MŠk LO1409; GA MŠk LM2015088 Institutional support: RVO:68378271 Keywords : field-effect transistors * side-chain * solar-cells * conjugated polymers * charge-transport * small molecules * photovoltaics * efficient * pigments Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 5.256, year: 2016

  19. CCDC 961393: Experimental Crystal Structure Determination : 3-(Adamantan-1-yl)-1-mesityl-1H-imidazol-3-ium chloride monohydrate

    KAUST Repository

    Queval, Pierre


    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  20. CCDC 992440: Experimental Crystal Structure Determination : hydrido-((1,2-phenylenebis(methylene))bis(bis(adamantan-1-yl)phosphine))-triphenylphosphine-palladium(ii) trifluoromethanesulfonate methanol solvate

    KAUST Repository

    Christl, Josefine T.


    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  1. CCDC 1024807: Experimental Crystal Structure Determination : 1,3-bis(Adamantan-1-yl)-1,3-dihydro-2H-imidazole-2-selenone

    KAUST Repository

    Vummaleti, Sai V. C.


    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  2. Insights from investigating the interactions of adamantane-based drugs with the M2 proton channel from the H1N1 swine virus

    International Nuclear Information System (INIS)

    Wang, Jing-Fang; Wei, Dong-Qing; Chou, Kuo-Chen


    The M2 proton channel is one of indispensable components for the influenza A virus that plays a vital role in its life cycle and hence is an important target for drug design against the virus. In view of this, the three-dimensional structure of the H1N1-M2 channel was developed based on the primary sequence taken from a patient recently infected by the H1N1 (swine flu) virus. With an explicit water-membrane environment, molecular docking studies were performed for amantadine and rimantadine, the two commercial drugs generally used to treat influenza A infection. It was found that their binding affinity to the H1N1-M2 channel is significantly lower than that to the H5N1-M2 channel, fully consistent with the recent report that the H1N1 swine virus was resistant to the two drugs. The findings and the relevant analysis reported here might provide useful structural insights for developing effective drugs against the new swine flu virus.

  3. 2 : 2 Fe(III): ligand and "adamantane core" 4 : 2 Fe(III): ligand (hydr)oxo complexes of an acyclic ditopic ligand

    DEFF Research Database (Denmark)

    Ghiladi, Morten; Larsen, Frank B.; McKenzie, Christine J.


    bond lengths of the two different octahedral iron sites: Fe -mu-OH, 1.953( 5), 2.013( 5) angstrom and Fe-mu-O, 1.803( 5), 1.802( 5) angstrom. The difference in ligand environment is too small for allowing Mossbauer spectroscopy to distinguish between the two crystallographically independent Fe sites...

  4. Inhibition of soluble epoxide hydrolase by cis-4-[4-(3-adamantan-1-ylureido)cyclohexyl-oxy]benzoic acid exhibits antihypertensive and cardioprotective actions in transgenic rats with angiotensin II-dependent hypertension

    Czech Academy of Sciences Publication Activity Database

    Neckář, Jan; Kopkan, L.; Husková, Z.; Kolář, František; Papoušek, František; Kramer, H. J.; Hwang, S.H.; Hammock, B.D.; Imig, J. D.; Malý, J.; Netuka, I.; Ošťádal, Bohuslav; Červenka, L.


    Roč. 122, č. 11 (2012), s. 513-525 ISSN 0143-5221 R&D Projects: GA AV ČR(CZ) IAAX01110901; GA AV ČR(CZ) KAN200520703; GA MŠk(CZ) 1M0510 Institutional research plan: CEZ:AV0Z50110509 Keywords : hypertension * angiotensin II * kidney * epoxyeicosatrienoic acids * soluble epoxide hydrolase inhibitor * myocardial ischemia/reperfusion injury Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 4.859, year: 2012

  5. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    type of interaction between C-H groups of adamantane and cloud of benzene is found as the important attraction for complex formation. The study also reveals that the methylene (-CH2) and methine (-CH) groups of adamantane interact with benzene resulting in different geometrical structures. And it is found that the ...

  6. The role of CH $\\ldots $ interaction in the stabilization of benzene ...

    Indian Academy of Sciences (India)

    type of interaction between C-H groups of adamantane and cloud of benzene is found as the important attraction for complex formation. The study also reveals that the methylene (-CH2) and methine (-CH) groups of adamantane interact with benzene resulting in different geometrical structures. And it is found that the ...

  7. J Chandrasekhar

    Indian Academy of Sciences (India)

    71 Feature Article. Molecule of the Month Adamantane - A Plastic Piece of Diamond ... 1997 pp 29-37 Series Article. Use of Isotopes for Studying Reaction Mechanisms Distinguishing between Single Minima and Rapidly Equilibrating Structures.

  8. computation of the stability constants for the inclusion complexes of

    African Journals Online (AJOL)

    PrF MU

    CD) with various adamantane derivatives (ADA), namely the amantadinium (AM), rimantadinium (RIM), and memantinium (MEM) cations have been determined by UV-Vis spectrophotometry. All experiments have been performed at a pH of 1.7 ...

  9. 3-Hydroxyadamantane-1-acetic acid

    Directory of Open Access Journals (Sweden)

    Yun-Long Feng


    Full Text Available The crystal structure of the title adamantane derivative, C12H18O3, has been determined by X-ray diffraction. The structure is stabilized by intermolecular O—H...O hydrogen bonds, forming a chain.

  10. Exploring a pocket for polycycloaliphatic groups in the CXCR3 receptor with the aid of a modular synthetic strategy. (United States)

    Wijtmans, Maikel; Verzijl, Dennis; van Dam, Cindy M E; Bosch, Leontien; Smit, Martine J; Leurs, Rob; de Esch, Iwan J P


    A CXCR3 pocket capable of accommodating polycycloaliphatics was explored using a modular synthetic strategy. The systematic studies reveal that the tricyclic 2-adamantane and bicyclic (iso)bornyl group are efficiently recognized by CXCR3.

  11. Molecule of the Month -66 ...

    Indian Academy of Sciences (India)

    Molecule of the Month. Adamantane - A Plastic Piece of Diamond. J Chandrasekhar is with the Department of. Organic Chemistry, Indian. Institute of Science,. Banga1ore. (1). The challenging goal of making other substances with all the properties of diamond continues to be pursued, with some success. J Chandrasekhar.

  12. Molecule of the Month

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 16; Issue 12. Molecule of the Month - Adamantane - A Plastic Piece of Diamond. J Chandrasekhar. Volume 16 Issue 12 December 2011 pp 1232-1237. Fulltext. Click here to view fulltext PDF. Permanent link:

  13. Radiation chemistry of plastic crystals. Annual progress report, November 1, 1975--October 31, 1976

    International Nuclear Information System (INIS)

    Klingen, T.J.


    Results of research on synthesis and plastic crystallinity of adamantane derivatives are presented. Results of electo-optical studies are included along with results of 1-phenyl-o-carborane radiolysis, co-polymerization of o-carborane, and 1-vinyl-o-carborane

  14. Glycosphingolipid synthesis inhibitor AMP-DNM lowers plasma cholesterol levels by promoting fecal cholesterol excretion without inhibiting cholesterol absorption

    NARCIS (Netherlands)

    Vrins, Carlos L. J.; Bietrix, Florence; Lombardo, Elisa; van Roomen, Cindy P. A. A.; Ottenhoff, Roelof; Overkleeft, Herman S.; Aerts, Johannes M.


    Inhibition of glycosphingolipid synthesis with iminosugar N-(5'-adamantane-1'-yl-methoxy)-pentyl-1-deoxynojirimycin (AMP-DNM) increases fecal neutral sterol output in mice. To investigate which pathways were involved in this increase, C57BI/6J mice were treated with AMP-DNM and/or ezetimibe. Fecal

  15. Total Synthesis of Plukenetione A (United States)

    Zhang, Qiang; Mitasev, Branko; Qi, Ji; Porco, John A.


    We describe an alkylative dearomatization/acid-mediated adamantane annulation sequence which allows facile access to type A polyprenylated acylphloroglucinol (PPAP) natural products including plukenetione A. Introduction of the 2-methyl-1-propenyl moiety was achieved via stereodivergent SN2 and SN1 cyclizations of allylic alcohol substrates. PMID:20843036

  16. Electrophilic reactions at single bonds. Ionic chlorination of hydrocarbons catalyzed by silica gel

    International Nuclear Information System (INIS)

    Gonzalez, A.G.; La Fuente, G. de; Trujillo, J.


    Chlorination of adamantane, bicyclo(3.3.1)nonane, bicyclo(2.2.2)octane, bicyclo(3.2.1)octane, norbornane and 2,5-dimethylhexane, absorbed on silica gel with chlorine, was studied. High yield of ionic chlorination at bridgehead carbon was achieved with the less-strained hydrocarbons. (author)

  17. Resonance – Journal of Science Education | News

    Indian Academy of Sciences (India)

    What's New in Computers? Will the Computer Become the World Chess Champion? K S R Anjaneyulu · More Details Fulltext PDF. pp 66-71 Feature Article. Molecule of the Month Adamantane - A Plastic Piece of Diamond · J Chandrasekhar · More Details Fulltext PDF. pp 72-74 Classroom. The Concept of Experiment in ...

  18. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    adamantan-2-ylidene)benzohydrazide followed by the quantum chemical calculations at the DFT level of theory have identified four stable conformers of this potential antibacterial agent in solution: one “central” cis- and three (“central”, “left” and “right”) ...

  19. Author Details

    African Journals Online (AJOL)

    Vashi, PR. Vol 54 (2001) - Articles Stability Constants of the Inclusion Complexes of ß-Cyclodextrin with Various Adamantane Derivatives. A UV-Vis Study Abstract PDF. ISSN: 0379-4350. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

  20. Author Details

    African Journals Online (AJOL)

    Application of Artificial Neural Networks for Analysis of Highly Overlapped and Disturbed Differential Pulse Polarographic Peaks in the Region of Hydrogen Evolution Abstract PDF · Vol 54 (2001) - Articles Stability Constants of the Inclusion Complexes of ß-Cyclodextrin with Various Adamantane Derivatives. A UV-Vis Study


    Calcined vanadium phosphorus oxide (VPO) prepared by an organic route is found to be an efficient catalyst for the oxidation of various alkanes such as cyclopentane, cyclohexane, n-hexane, cycloheptane, cyclooctane, cyclodecane and adamantane in acetonitrile solvent using the env...

  2. Fluorine-18 radiolabelling, biodistribution studies and preliminary pet evaluation of a new memantine derivative for imaging the NMDA receptor

    NARCIS (Netherlands)

    Ametamey, SM; Samnick, S; Leenders, KL; Vontobel, P; Quack, G; Parsons, CG; Schubiger, PA


    A synthetic method has been established for preparing [F-18]1-amino-3-fluoromethyl-5-methyl-adamantane ([F-18]AFA). Biodistrubution of the radiotracer; in mice showed high brain uptake. The peak uptake (3.78 I.D/g organ) for the brain occurred at 30 min after injection. Accumulation of radioactivity

  3. alexander m andrianov

    Indian Academy of Sciences (India)

    ALEXANDER M ANDRIANOV. Articles written in Journal of Chemical Sciences. Volume 128 Issue 12 December 2016 pp 1933-1942 Regular Article. Structure of N'-(adamantan-2-ylidene)benzohydrazide, a potential antibacterial agent, in solution: Molecular dynamics simulations, quantum chemical calculations and ...

  4. Molecule of the Month

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 9. Molecule of the Month Adamantane - A Plastic Piece of Diamond. J Chandrasekhar. Feature Article Volume 1 Issue 9 September 1996 pp 66-71. Fulltext. Click here to view fulltext PDF. Permanent link:

  5. Molecular dynamics simulation

    Indian Academy of Sciences (India)

    positively modulates the therapeutic index of many compounds.1,2 Derivatives of adamantane are known for their antiviral activity against Influenza A3 5 and ..... Abdul-Malek S. Al-Tamimi and Ali A. El-Emam would like to extend their appreciation to the Deanship of. Scientific Research at King Saud University for fund-.


    Indian Academy of Sciences (India)

    ACrab in the Lab that Identified High and Low. Tides in the Sea Two Miles Away. (8) 778 (RF). A Letter to a Young Friend (12) 1110 (RF). A short biography of Israel Moiseevich Gelfand. (2) 104 (AIB). Acrocarpus fraxinifolius (1) (FT). Adamantane (12) 1232 (GA). Adansonia digitata L. (2) (FT). Additor (3) 220 (GA). Aerosols ...

  7. Generation of liquid crystallinity from a Td-symmetry central unit. (United States)

    Sayed, Sayed Mir; Lin, Bao-Ping; Yang, Hong


    A series of new columnar liquid crystals containing an adamantane central unit with its four bridgehead positions partially or fully decorated with different numbers (1-4) of 3,4,5-tris(dodecyloxy)phenyl carbamoyl groups were designed and investigated carefully to explore the structure-property correlations. The molecular structures and mesomorphic properties of the DLCs were characterized by (1)H-NMR, (13)C-NMR, IR, UV-vis, POM, DSC and XRD. It was found that the mesophase symmetry and thermal stability were extremely dependent on the structures of the adamantane derivatives. No mesophase was observed for the 1-adamantanecarboxylic acid derivative ADLC1, while two different mesophases were observed for ADLC2, a 1,3-disubstituted derivative functionalized with two 3,4,5-tris(dodecyloxy)phenyl carbamoyl groups at two symmetric bridgehead positions. At lower temperature ADLC2 exhibited a rectangular columnar phase, which switched to a square columnar phase possessing a wide temperature range. Similarly, a hexagonal columnar mesophase was observed for the bridgehead trisubstituted adamantane molecule ADLC3. Interestingly, the fully bridgehead-functionalized 1,3,5,7-tetrasubstituted adamantane compound ADLC4 completely lost liquid crystallinity.

  8. Stability Constants of the Inclusion Complexes of ß-Cyclodextrin with ...

    African Journals Online (AJOL)

    The stability constants for the inclusion complexes of ß-cyclodextrin (ß-CD) with various adamantane derivatives (ADA), namely the amantadinium (AM), rimantadinium (RIM), and memantinium (MEM) cations have been determined by UV-Vis spectrophotometry. All experiments have been performed at a pH of 1.7 and 25 º ...

  9. NMR studies of liquids and disordered solids at high pressure. [Pulsed and high-pressure techniques

    Energy Technology Data Exchange (ETDEWEB)

    Fury, Michael Andrew [Univ. of Illinois, Urbana-Champaign, IL (United States)


    Molecular reorientation and translation in molecular liquids was studied. A dominant premise in these studies was that, except in strongly hydrogen-bonded systems such as water, the dynamics of a liquid may be considered to be a series of impulsive collisions. Details of the behavior would be dominated by the shape and size of the molecules under constant packing conditions. The second area of effort was in the plastic crystalline solid phase of two globular molecules, adamantane and cyclohexane. The NMR technique was used in these studies to measure self-diffusion coefficients and spin-lattice relaxation times. The applicability of pulsed NMR techniques to the study of the kinetics of order--disorder phase transitions in solid adamantane was demonstrated.

  10. symm-Tetramethylenecyclooctane: en route to polyspirocycles. (United States)

    Averina, Elena B; Sedenkova, Kseniya N; Bakhtin, Stanislav G; Grishin, Yuri K; Kutateladze, Andrei G; Roznyatovsky, Vitaly A; Rybakov, Victor B; Butov, Gennady M; Kuznetsova, Tamara S; Zefirov, Nikolay S


    A straightforward gram-scale synthesis of 1,3,5,7-tetrakis(methylidene)cyclooctane (TMCO) from commercial adamantane-1,3-dicarboxylic acid has been developed. TMCO exhibits high reactivity toward a number of carbenes and epoxidizing reagents, undergoing multiple cyclopropanations, dihalocyclopropanations, or epoxidations of four double bonds to yield polyspirocyclic products. Stereochemical features of polyspirocyclopropanated compounds have been thoroughly examined in experimental (NMR) and theoretical (DFT) studies. Comprehensive stereochemical assignment of TMCO adducts with dihalocarbenes and spiroepoxy products was achieved. The conditions of the formation of 1-methyl-3,7-bis(methylidene)bicyclo[3.3.1]nonane from the adamantane derivative were optimized, and diadducts of this diene with dihalocarbenes were isolated and characterized.

  11. 2-(1-Adamantyl-1-(3-aminophenylethanol

    Directory of Open Access Journals (Sweden)

    Michal Rouchal


    Full Text Available In the crystal structure of the title compound, C18H25NO, molecules are linked via O—H...N hydrogen bonds, forming chains parallel to the c axis. Additional weak N—H...O interactions stabilize the crystal packing. The adamantane cage consists of three fused cyclohexane rings in almost ideal chair conformations, with C—C—C angles in the range 107.9 (10–111.3 (11°.

  12. A Nexus between Theory and Experiment: Non-Empirical Quantum Mechanical Computational Methodology Applied to Cucurbit[n]urilGuest Binding Interactions

    Czech Academy of Sciences Publication Activity Database

    Hostaš, Jiří; Sigwalt, D.; Šekutor, M.; Ajani, Haresh; Dubecký, M.; Řezáč, Jan; Zavalij, P. Y.; Cao, L.; Wohlschlager, Ch.; Mlinaric-Majerski, K.; Isaacs, L.; Glaser, R.; Hobza, Pavel


    Roč. 22, č. 48 (2016), s. 17226-17238 ISSN 0947-6539 R&D Projects: GA ČR(CZ) GBP208/12/G016 Institutional support: RVO:61388963 Keywords : adamantane-/diamantane-skeleton guests * biomimetic complexes * BLYP-D3 quantum mechanical calculations * cucurbit[n]uril * host-guest complexes * primary ammonium loops Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.317, year: 2016

  13. 1H Cramps Based on Trev (United States)

    Buszko, M. L.; Bronnimann, C. E.; Maciel, G. E.

    Line-narrowing effects of the 1H TREV-8 pulse sequence applied to solids rotating at the magic angle have been examined. Polycrystalline samples of adipic, malonic, and fumaric acids, adamantane, a barley seed, and a pyridine-saturated coal sample were examined. The TREV-based 1H CRAMPS technique is seen to provide reasonably effective line narrowing for both "soft" solids (adamantane) and rigid solids (carboxylic acids), enabling 1H chemical-shift fine structure to be observed. For adamantane, the 1H linewidth is reduced from about 13 kHz (static) to 40 Hz (CRAMPS) at a 840 Hz MAS rate and a pulse spacing (τ) of 7.8 μs. The line-narrowing efficiency increases for larger τ values, but does not approach the efficiency of BR-24. However, unlike the case for BR-24 or other multiple-pulse line-narrowing sequences based on the formation of solid echoes, the line-narrowing efficiency of TREV-8 is sustained for large offsets; this feature, along with a relatively large bandwidth, may be an important factor when the sequence is implemented in 19F CRAMPS and in solid-sample imaging studies. TREV-CRAMPS may also be useful for samples in which the somewhat inferior line-narrowing behavior may be masked by line-broadening effects not based on homonuclear dipolar interactions.

  14. pH-Sensitive Micelles Based on Star Copolymer Ad-(PCL-b-PDEAEMA-b-PPEGMA4 for Controlled Drug Delivery

    Directory of Open Access Journals (Sweden)

    Huiyan Yang


    Full Text Available Enhancing drug loading efficacy and stability of polymeric micelles remains a grand challenge. Here we develop adamantane-based star copolymers adamantane-[poly(ε-caprolactone-b-poly(2-(diethylaminoethyl methacrylate-b-poly(poly(ethylene glycol methyl ether methacrylate]4 (Ad-(PCL-b-PDEAEMA-b-PPEGMA4 and their self-assembled micelles for controlled drug delivery. Results show that the polymers have excellent stability in solution with low critical micelle concentration (CMC (0.0025–0.0034 mg/mL and the apparent base dissociation constant (pKb of the polymers is from 5.31 to 6.05. Dynamic light scattering analysis exhibits the great environmental response capability of the pH-sensitive micelles according to particle sizes and zeta potentials. With the synergy effect of the adamantane and hydrophobic block, the micelles display the high Doxorubicin (DOX loading efficacy (up to 22.4%. The DOX release study shows that the micelles are capable of controlled release for drug. This work indicates the Ad-(PCL-b-PDEAEMA-b-PPEGMA4 micelles may provide new guidelines for drug control and release system in overcoming cancer treatment.

  15. Host-Guest Complexes of Cyclodextrins and Nanodiamonds as a Strong Non-Covalent Binding Motif for Self-Assembled Nanomaterials. (United States)

    Schibilla, Frauke; Voskuhl, Jens; Fokina, Natalie A; Dahl, Jeremy E P; Schreiner, Peter R; Ravoo, Bart Jan


    We report the inclusion of carboxy- and amine-substituted molecular nanodiamonds (NDs) adamantane, diamantane, and triamantane by β-cyclodextrin and γ-cyclodextrin (β-CD and γ-CD), which have particularly well-suited hydrophobicity and symmetry for an optimal fit of the host and guest molecules. We studied the host-guest interactions in detail and generally observed 1:1 association of the NDs with the larger γ-CD cavity, but observed 1:2 association for the largest ND in the series (triamantane) with β-CD. We found higher binding affinities for carboxy-substituted NDs than for amine-substituted NDs. Additionally, cyclodextrin vesicles (CDVs) were decorated with d-mannose by using adamantane, diamantane, and triamantane as non-covalent anchors, and the resulting vesicles were compared with the lectin concanavalin A in agglutination experiments. Agglutination was directly correlated to the host-guest association: adamantane showed lower agglutination than di- or triamantane with β-CDV and almost no agglutination with γ-CDV, whereas high agglutination was observed for di- and triamantane with γ-CDV. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Ordered phases of encapsulated diamondoids into carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Legoas, S B [Departamento de Fisica, CCT, Universidade Federal de Roraima, 69304-000, Boa Vista, Roraima (Brazil); Dos Santos, R P B; Troche, K S; Galvao, D S [Instituto de Fisica ' Gleb Wataghin' , Universidade Estadual de Campinas, 13083-970, Campinas, Sao Paulo (Brazil); Coluci, V R, E-mail: [Faculdade de Tecnologia, Universidade Estadual de Campinas, 13484-332, Limeira, Sao Paulo (Brazil)


    Diamondoids are hydrogen-terminated nanosized diamond fragments that are present in petroleum crude oil at low concentrations. These fragments are found as oligomers of the smallest diamondoid, adamantane (C{sub 10}H{sub 16}). Due to their small size, diamondoids can be encapsulated into carbon nanotubes to form linear arrangements. We have investigated the encapsulation of diamondoids into single walled carbon nanotubes with diameters between 1.0 and 2.2 nm using fully atomistic simulations. We performed classical molecular dynamics and energy minimizations calculations to determine the most stable configurations. We observed molecular ordered phases (e.g. double, triple, 4- and 5-stranded helices) for the encapsulation of adamantane, diamantane, and dihydroxy diamantane. Our results also indicate that the functionalization of diamantane with hydroxyl groups can lead to an improvement on the molecular packing factor when compared to non-functionalized compounds. Comparisons to hard-sphere models revealed differences, especially when more asymmetrical diamondoids were considered. For larger diamondoids (i.e., adamantane tetramers), we have not observed long-range ordering but only a tendency to form incomplete helical structures. Our calculations predict that thermally stable (at least up to room temperature) complex ordered phases of diamondoids can be formed through encapsulation into carbon nanotubes.

  17. Towards double-functionalized small diamondoids: selective electronic band-gap tuning

    International Nuclear Information System (INIS)

    Adhikari, Bibek; Fyta, Maria


    Diamondoids are nanoscale diamond-like cage structures with hydrogen terminations, which can occur in various sizes and with a diverse type of modifications. In this work, we focus on the structural alterations and the effect of doping and functionalization on the electronic properties of diamondoids, from the smallest adamantane to heptamantane. The results are based on quantum mechanical calculations. We perform a self-consistent study, starting with doping the smallest diamondoid, adamantane. Boron, nitrogen, silicon, oxygen, and phosphorus are chosen as dopants at sites which have been previously optimized and are also consistent with the literature. At a next step, an amine- and a thiol- group are separately used to functionalize the adamantane molecule. We mainly focus on a double functionalization of diamondoids up to heptamantane using both these atomic groups. The effect of isomeration in the case of tetramantane is also studied. We discuss the higher efficiency of a double-functionalization compared to doping or a single-functionalization of diamondoids in tuning the electronic properties, such as the electronic band-gap, of modified small diamondoids in view of their novel nanotechnological applications. (paper)

  18. Inhibitors of the influenza A virus M2 proton channel discovered using a high-throughput yeast growth restoration assay.

    Directory of Open Access Journals (Sweden)

    Aruna D Balgi

    Full Text Available The M2 proton channel of the influenza A virus is the target of the anti-influenza drugs amantadine and rimantadine. The effectiveness of these drugs has been dramatically limited by the rapid spread of drug resistant mutations, mainly at sites S31N, V27A and L26F in the pore of the channel. Despite progress in designing inhibitors of V27A and L26F M2, there are currently no drugs targeting these mutated channels in clinical trials. Progress in developing new drugs has been hampered by the lack of a robust assay with sufficient throughput for discovery of new active chemotypes among chemical libraries and sufficient sensitivity to provide the SAR data essential for their improvement and development as drugs. In this study we adapted a yeast growth restoration assay, in which expression of the M2 channel inhibits yeast growth and exposure to an M2 channel inhibitor restores growth, into a robust and sensitive high-throughput screen for M2 channel inhibitors. A screen of over 250,000 pure chemicals and semi-purified fractions from natural extracts identified 21 active compounds comprising amantadine, rimantadine, 13 related adamantanes and 6 non-adamantanes. Of the non-adamantanes, hexamethylene amiloride and a triazine derivative represented new M2 inhibitory chemotypes that also showed antiviral activity in a plaque reduction assay. Of particular interest is the fact that the triazine derivative was not sufficiently potent for detection as an inhibitor in the traditional two electrode voltage clamp assay for M2 channel activity, but its discovery in the yeast assay led to testing of analogues of which one was as potent as amantadine.

  19. Reaction mechanisms of ruthenium tetroxide mediated oxidations of organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Froehaug, Astrid Elisabeth


    This thesis reports a study of the mechanism of ruthenium tetroxide mediated oxidations of saturated hydrocarbons, ethers, alkenes and alcohols. Several methods were used. The RuO{sub 4}-mediated oxidations of adamantane and cis-decalin were studied in CCl{sub 4}-CH{sub 3}CN-H{sub 2}O and in acetone-water. The rate of reaction was found to be moderately influenced by the polarity of the solvent. Solvent properties other than the polarity were also found to influence the reaction rates. From the oxidations of adamantane and adamantane-1,3,5,7-d{sub 4} two primary kinetic deuterium isotope effects were found. These were comparable with the deuterium isotope effects found for the analogous oxidations of cis-decalin and cis-decalin-d{sub 18}. The results seem to exclude both a one step hydride abstraction reaction mechanism and a one step concerted mechanism, as well as a scheme where two such mechanisms compete. The observations may be explained by a two step reaction mechanism consisting of a pre-equilibrium with formation of a substrate-RuO{sub 4} complex followed by a concerted rate determining reaction. The RuO{sub 4}-mediated oxidation of ethers was of kinetic second order with a small enthalpy of activation and a large negative entropy of activation. Oxidation of cyclopropylmethyl methyl ether gave methyl cyclopropanecarboxylate, no rearranged products were observed. On RuO{sub 4} oxidations in CCl{sub 4} with NaIO{sub 4} as stoichiometric oxidant, no chlorinated products were observed. Several observations not in agreement with a hydride or a hydrogen abstraction mechanism may be explained by assuming that the reaction proceeds by either a concerted reaction or by a reversible oxidative addition of the ether to RuO{sub 4} followed by a slow concerted step. 228 refs., 9 figs., 27 tabs.

  20. Superstructures of fluorescent cyclodextrin via click-reaction

    Directory of Open Access Journals (Sweden)

    Arkadius Maciollek


    Full Text Available Mono-(6-azido-6-deoxy-β-cyclodextrin (CD was covalently attached to an alkyne-modified 5-methyl-2-(pyridin-2-ylthiazol-4-ol yielding a fluorophore containing CD in a click-type reaction. Intermolecular complexes were formed by poly(host–guest-interactions. The supramolecular structures were characterized by 1H NMR-ROESY spectroscopy, dynamic light scattering, UV–vis spectroscopy, fluorescence spectroscopy, and asymmetric flow field-flow fractionation. By adding potassium adamantane-1-carboxylate, the thiazol dye is displaced from the CD-cavity and the elongated noncovalent polymeric structures collapse.

  1. Preparation methods and properties of allylboranes

    International Nuclear Information System (INIS)

    Mikhajlov, B.M.


    The methods of synthesis and chemical properties of allylboron compounds of different types are considered as well as the application in organic chemistry, for example, for synthesis of 1-boroadamantane and adamantane compounds. PMR study of triallylborane reveals permanent allyl rearrangement. The paper describes the ability to complex formation, reactions with organometal compounds and some other agents, reactions with diborane and tetraalkyldiboranes, reactions with carbonyl compounds and nitriles, reactions with compounds containing activated double carbon-carbon bond, reactions with acetylene compounds, and reaction with allene compounds

  2. [Characteristics of antiischemic and nootropic properties of ademol in a rat model of acute brain ischemia]. (United States)

    Khodakivs'kyĭ, O A


    In experiments with the rat model of acute disorder of encephalic circulation (bilateral carotid occlusion) it was found that introduction of derivate of adamantan 1-adamantiloxy-3-morfolino-2 propanol (under conventional name ademol) in the dose 2 mg/kg intraabdominal in treatment regimen (in an hour after reconstruction of insult and further 1 time every 24 hours during 21 days) was accompanied by a recovery of mnemotropic properties and is more effective than cytikolin, resulting in a decreased lethality and neurological deficiency in acute and recovery periods of insults. The data received proved the usefulness of development of ademol based cerebroprotective remedy.

  3. Evaluation of experimental data for wax and diamondoids solubility in gaseous systems

    DEFF Research Database (Denmark)

    Mohammadi, Amir H.; Gharagheizi, Farhad; Eslamimanesh, Ali


    The Leverage statistical approach is herein applied for evaluation of experimental data of the paraffin waxes/diamondoids solubility in gaseous systems. The calculation steps of this algorithm consist of determination of the statistical Hat matrix, sketching the Williams Plot, and calculation......-Santiago and Teja correlations are used to calculate/estimate the solubility of paraffin waxes (including n-C24H50 to n-C33H68) and diamondoids (adamantane and diamantane) in carbon dioxide/ethane gases, respectively. It can be interpreted from the obtained results that the applied equations for calculation...

  4. 4-(1-Adamantylmethyl-N-(2-chloro-9-isopropyl-9H-purin-6-ylaniline

    Directory of Open Access Journals (Sweden)

    Michal Rouchal


    Full Text Available The asymmetric unit of the title compound, C25H30ClN5, consists of two molecules with slightly different geometrical parameters. The dihedral angles between the purine and benzene rings are 39.54 (5 and 23.69 (5° in the two molecules. The adamantane cages consist of three fused cyclohexane rings in classical chair conformations, with C—C—C angles in the range 108 (2–111 (2°. In the crystal, molecules are linked into dimers via two N—H...N hydrogen bonds.

  5. 4-(1-Adamantylmeth-yl)-N-(2-chloro-9-isopropyl-9H-purin-6-yl)aniline. (United States)

    Rouchal, Michal; Nečas, Marek; Vícha, Robert


    The asymmetric unit of the title compound, C(25)H(30)ClN(5), consists of two mol-ecules with slightly different geometrical parameters. The dihedral angles between the purine and benzene rings are 39.54 (5) and 23.69 (5)° in the two mol-ecules. The adamantane cages consist of three fused cyclo-hexane rings in classical chair conformations, with C-C-C angles in the range 108 (2)-111 (2)°. In the crystal, mol-ecules are linked into dimers via two N-H⋯N hydrogen bonds.

  6. Computer simulation of a phosphorescent probe inside β -cyclodextrin matrices (United States)

    Odinokov, Alexey; Alfimov, Mikhail


    Molecular dynamics simulations of the different self-assembled structures based on the β -cyclodextrin and adamantane were performed. The line shift and non-uniform broadening of the T1 →S0 transition of naphthalene molecule inserted into these structures were calculated. It was found that line width is mainly governed by the nearest-neighbor environment. The most important factor was the existence of the typical "sandwich" structural pattern. The main findings provide a way to the rational design of new materials for nanophotonics.

  7. Patterns in influenza antiviral medication use before and during the 2009 H1N1 pandemic, Vaccine Safety Datalink Project, 2000-2010. (United States)

    Greene, Sharon K; Shay, David K; Yin, Ruihua; McCarthy, Natalie L; Baxter, Roger; Jackson, Michael L; Jacobsen, Steven J; Nordin, James D; Irving, Stephanie A; Naleway, Allison L; Glanz, Jason M; Lieu, Tracy A


    U.S. recommendations for using influenza antiviral medications changed in response to viral resistance (to reduce adamantane use) and during the 2009 H1N1 pandemic (to focus on protecting high-risk patients). Little information is available on clinician adherence to these recommendations. We characterized population-based outpatient antiviral medication usage, including diagnosis and testing practices, before and during the pandemic. Eight medical care organizations in the Vaccine Safety Datalink Project provided data on influenza antiviral medication dispensings from January 2000 through June 2010. Dispensing rates were explored in relation to changes in recommendations and influenza diagnosis and laboratory testing frequencies. Factors associated with oseltamivir dispensings in pandemic versus pre-pandemic periods were identified using multivariable logistic regression. Antiviral use changed coincident with recommendations to avoid adamantanes in 2006, to use alternatives to oseltamivir in 2008, and to use oseltamivir during the pandemic. Of 38,019 oseltamivir dispensings during the pandemic, 31% were to patients not assigned an influenza diagnosis, and 97% were to patients not tested for influenza. Oseltamivir was more likely to be dispensed in pandemic versus pre-pandemic periods to patients change antiviral prescribing based on resistance and to focus on high-risk patients during the pandemic. Medications were commonly dispensed to patients without influenza diagnoses and tests, suggesting that antiviral dispensings may offer useful supplemental data for monitoring influenza incidence. © 2012 Blackwell Publishing Ltd.

  8. Flotation Assembly of Large-Area Ultrathin MWCNT Nanofilms for Construction of Bioelectrodes

    Directory of Open Access Journals (Sweden)

    Andrew J. Gross


    Full Text Available We report a simple, versatile, and rapid method for the fabrication of optically-transparent large-area carbon nanotube (CNT films via flotation assembly. After solvent-induced assembly, floating films were transferred to a flat supporting substrate to form conductive and transparent CNT film electrodes. The resulting electrodes, with uniform 40 ± 20 nm multi-walled CNT (MWCNT layers, were characterized by electrochemical and microscopy methods. The flotation method does not require specialized thin-film instrumentation and avoids the need for surfactants and pre-oxidized CNTs which can hamper electrochemical performance. A proof-of-concept nanostructured bioelectrode demonstrating high sensitivity for glucose was developed with an electropolymerized poly(pyrene-adamantane layer for host–guest immobilization of active β-cyclodextrin tagged GOx enzymes. The polymer provides pyrene groups for cross-linking to CNTs and pendant adamantane groups for binding the β-cyclodextrin groups of the tagged enzyme. This demonstration offers a new approach for the preparation of stable and transparent CNT film electrodes with attractive electrochemical properties towards future photobio- and bio-electrochemical fuel cells, electrochemical sensors, and electroanalysis.

  9. View at Croatian Chemistry through Meetings of Croatian

    Directory of Open Access Journals (Sweden)

    Trinajstić, N.


    Full Text Available The 20th Croatian meeting of chemists and chemical engineers was a proper occasion to consider the past meetings and their role in the development of Croatian chemistry and chemical engineering last 40 years, because these meetings reflect to a large extent the state of these sciences in Croatia. The circumstances that lead to establishment of the Croatian meetings of chemists and chemical engineers and the role of Professor Marijan Laaan (1919-1981 who started these meetings by organizing the first one are described. He also organized the second and the seventh meeting. All persons who chaired these meetings are mentioned, as well as all the lecturers who won the Nobel Prize in chemistry. Especially emphasized is the participation of Vladimir Prelog (1906-1998 since the twentieth meeting was dedicated to him and to Leopold Ružička (1887-1976 - two excellent Croatian chemists who for their first-class research in organic chemistry won the Nobel Prize (Ružička in 1939 and Prelog 1975. The places where the meetings were held are listed. The structure of the meetings when the change of the meetings' title happened is delineated and the representation of various branches of chemistry according to the number of contributions is discussed. Similarly, the Croatian institutions according to the number ofcontributions of their staff-members and the contributors with the highest number of communications at each meeting are pointed out. Emphasized is the international character of these meetings and the countries from which the participants came are listed. Finally, only one contribution is discussed in detail - the report by Kata Mlinarić-Majerski and Zdenko Majerski on the preparation of [3.1.1]propellane inserted in the structure of adamantane. Adamantane chemistry in Croatia started with the first ever adamantane synthesis in 1941, when Prelog and Seiwerth prepared this cage hydrocarbon and is still going strong due to efforts by Kata Mlinaria

  10. Cyclodextrin-Based [1]Rotaxanes on Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Yanli Zhao


    Full Text Available Transformation of mechanically interlocked molecules (e.g., rotaxanes and catenanes into nanoscale materials or devices is an important step towards their real applications. In our current work, an azobenzene-modified β-cyclodextrin (β-CD derivative that can form a self-inclusion complex in aqueous solution was prepared. The self-included β-CD derivative was then functionalized onto a gold nanoparticle (AuNP surface via a ligand-exchange reaction in aqueous solution, leading to the formation of AuNP-[1]rotaxane hybrids. Corresponding non-self-included β-CD derivative functionalized AuNPs were also developed in a DMF/H2O mixture solution for control experiments. These hybrids were fully characterized by UV-vis and circular dichroism spectroscopies, together with transmission electron microscopy (TEM. The competitive binding behavior of the hybrids with an adamantane dimer was investigated.

  11. Small organic compounds enhance antigen loading of class II major histocompatibility complex proteins by targeting the polymorphic P1 pocket

    DEFF Research Database (Denmark)

    Höpner, Sabine; Dickhaut, Katharina; Hofstätter, Maria


    immune responses by catalyzing the peptide loading of human class II MHC molecules HLA-DR. Here we show now that they achieve this by interacting with a defined binding site of the HLA-DR peptide receptor. Screening of a compound library revealed a set of adamantane derivatives that strongly accelerated...... the peptide loading rate. The effect was evident only for an allelic subset and strictly correlated with the presence of glycine at the dimorphic position beta86 of the HLA-DR molecule. The residue forms the floor of the conserved pocket P1, located in the peptide binding site of MHC molecule. Apparently......-susceptible" MHC molecules. As catalysts of antigen loading, compounds targeting P1 may be useful molecular tools to amplify the immune response. The observation, however, that the ligand repertoire can be affected through polymorphic sites form the outside may also imply that environmental factors could induce...

  12. Diamond-like nanoparticles influence on flavonoids transport: molecular modelling (United States)

    Plastun, Inna L.; Agandeeva, Ksenia E.; Bokarev, Andrey N.; Zenkin, Nikita S.


    Intermolecular interaction of diamond-like nanoparticles and flavonoids is investigated by numerical simulation. Using molecular modelling by the density functional theory method, we analyze hydrogen bonds formation and their influence on IR - spectra and structure of molecular complex which is formed due to interaction between flavonoids and nanodiamonds surrounded with carboxylic groups. Enriched adamantane (1,3,5,7 - adamantanetetracarboxylic acid) is used as an example of diamond-like nanoparticles. Intermolecular forces and structure of hydrogen bonds are investigated. IR - spectra and structure parameters of quercetin - adamantanetetracarboxylic acid molecular complex are obtained by numerical simulation using the Gaussian software complex. Received data coincide well with experimental results. Intermolecular interactions and hydrogen bonding structure in the obtained molecular complex are examined. Possibilities of flavonoids interaction with DNA at the molecular level are also considered.

  13. Cyclodextrin-containing layer-by-layer films and microcapsules: Synthesis and applications

    Directory of Open Access Journals (Sweden)

    Uichi Akiba


    Full Text Available This article reviews the synthesis and applications of cyclodextrin (CD-containing layer-by-layer (LbL films and microcapsules. CD-containing LbL films and microcapsules have been synthesized through the electrostatic interactions between charged CDs and polyelectrolytes or the formation of host–guest complexes. In the former strategy, sulfonated and carboxylated CDs are often combined with oppositely charged polyelectrolytes. In contrast, in the latter strategy, CD-bearing polymers and guest-modified polymers are used as components of LbL assembly. Typical guest molecules include adamantane, ferrocene, and azobenzene derivatives. Electrochemical biosensors have been constructed by coating the surface of electrodes with CD-containing LbL films. In addition, CD-containing LbL assemblies are used as scaffolds for constructing drug delivery systems, in which hydrophobic, poorly soluble drugs are loaded on the film through host–guest complexation.

  14. Gas-phase reactions of cationic vanadium-phosphorus oxide clusters with C2H(x) (x=4, 6): a DFT-based analysis of reactivity patterns. (United States)

    Dietl, Nicolas; Zhang, Xinhao; van der Linde, Christian; Beyer, Martin K; Schlangen, Maria; Schwarz, Helmut


    The reactivities of the adamantane-like heteronuclear vanadium-phosphorus oxygen cluster ions [V(x)P(4-x)O(10)](.+) (x=0, 2-4) towards hydrocarbons strongly depend on the V/P ratio of the clusters. Possible mechanisms for the gas-phase reactions of these heteronuclear cations with ethene and ethane have been elucidated by means of DFT-based calculations; homolytic C-H bond activation constitutes the initial step, and for all systems the P-O(.) unit of the clusters serves as the reactive site. More complex oxidation processes, such as oxygen-atom transfer to, or oxidative dehydrogenation of the hydrocarbons require the presence of a vanadium atom to provide the electronic prerequisites which are necessary to bring about the 2e(-) reduction of the cationic clusters. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Gas-Phase Reactions of Cationic Vanadium-Phosphorus Oxide Clusters with C2Hx (x=4, 6): A DFT-Based Analysis of Reactivity Patterns (United States)

    Dietl, Nicolas; Zhang, Xinhao; van der Linde, Christian; Beyer, Martin K; Schlangen, Maria; Schwarz, Helmut


    The reactivities of the adamantane-like heteronuclear vanadium-phosphorus oxygen cluster ions [VxP4−xO10].+ (x=0, 2–4) towards hydrocarbons strongly depend on the V/P ratio of the clusters. Possible mechanisms for the gas-phase reactions of these heteronuclear cations with ethene and ethane have been elucidated by means of DFT-based calculations; homolytic C–H bond activation constitutes the initial step, and for all systems the P–O. unit of the clusters serves as the reactive site. More complex oxidation processes, such as oxygen-atom transfer to, or oxidative dehydrogenation of the hydrocarbons require the presence of a vanadium atom to provide the electronic prerequisites which are necessary to bring about the 2e− reduction of the cationic clusters. PMID:23322620

  16. Synthesis of higher diamondoids by pulsed laser ablation plasmas in supercritical CO2 (United States)

    Nakahara, Sho; Stauss, Sven; Kato, Toru; Sasaki, Takehiko; Terashima, Kazuo


    Pulsed laser ablation (wavelength 532 nm; fluence 18 J/cm2; pulse width 7 ns; repetition rate 10 Hz) of highly oriented pyrolytic graphite was conducted in adamantane-dissolved supercritical CO2 with and without cyclohexane as a cosolvent. Micro-Raman spectroscopy of the products revealed the presence of hydrocarbons possessing sp3-hybridized carbons similar to diamond structures. The synthesis of diamantane and other possible diamondoids consisting of up to 12 cages was confirmed by gas chromatography-mass spectrometry. Furthermore, gas chromatography-mass spectrometry measurements of samples before and after pyrolysis treatment indicate the synthesis of the most compact decamantane, namely, superadamantane. It is thought that oxidant species originating from CO2 during pulsed laser ablation might lead to the selective dissociation of C-H bonds, enabling the synthesis of low H/C ratio molecules. Therefore, laser ablation in supercritical CO2 is proposed as a practical method for synthesizing diamondoids.

  17. Non-Competitive NMDA Receptor Antagonist Hemantane Reduces Ethanol Consumption in Long-Term Alcohol Experienced Rats. (United States)

    Kolik, L G; Nadorova, A V; Seredenin, S B


    Activity of hemantane, an amino adamantane derivative, exhibiting the properties of lowaffinity non-competitive NMDA receptor antagonist, was evaluated in experimental in vivo models of alcoholism. Hemantane had no effects on the formation and manifestation of behavioral sensitization to ethanol in DBA/2 mice. Under conditions of free choice between 10% ethanol and water, hemantane (20 mg/kg/day for 14 days, intraperitoneally) significantly reduced the daily ethanol intake in random-bred male rats with formed alcohol motivation (>4 g/kg of ethanol). During modelling of withdrawal syndrome, hemantane administered intraperitoneally in doses of 5-20 mg/kg dose-dependently attenuated alcohol-deprivation effect after acute withdrawal with no effects on protracted abstinence. It was found that hemantane suppressed alcohol drinking behavior in long-term ethanol experienced rats and attenuated alcohol-seeking behavior after acute withdrawal.

  18. Molecular and phylogenetic analysis of matrix gene of avian influenza viruses isolated from wild birds and live bird markets in the USA. (United States)

    Chander, Yogesh; Jindal, Naresh; Sreevatsan, Srinand; Stallknecht, David E; Goyal, Sagar M


    Wild birds are the natural hosts for influenza A viruses (IAVs) and provide a niche for the maintenance of this virus. This study was undertaken to analyze nucleotide sequences of the matrix (M) gene of AIVs isolated from wild birds and live bird markets (LBMs) to index the changes occurring in this gene. M-gene of 229 avian influenza virus (AIV) isolates obtained from wild birds and LBMs was amplified and sequenced. Full-length sequences (∼900 nt.) thus obtained were analyzed to identify changes that may be associated with resistance to adamantanes. Phylogenetic analysis of all sequences was performed using clustalw, and evolutionary distances were calculated by maximum composite likelihood method using mega (ver. 5.0) software. Twenty-seven different viral subtypes were represented with H3N8 being the most dominant subtype in wild birds and H7N2 being the predominant subtype among isolates from LBMs. Phylogenetic analysis of the M-gene showed a high degree of nucleotide sequence identity with US isolates of AIVs but not with those of Asian or European lineages. While none of the isolates from wild birds had any antiviral resistance-associated mutations, 17 LBM isolates carried polymorphisms known to cause reduced susceptibility to antiviral drugs (adamantanes). Of these 17 isolates, 16 had S31N change and one isolate had V27A mutation. These results indicate independent evolution of M-gene in the absence of any antiviral drugs leading to mutations causing resistance indicating the need for continued active surveillance of AIVs. © 2012 John Wiley & Sons Ltd.

  19. pH-dependent binding of guests in the cavity of a polyhedral coordination cage: reversible uptake and release of drug molecules. (United States)

    Cullen, William; Turega, Simon; Hunter, Christopher A; Ward, Michael D


    A range of organic molecules with acidic or basic groups exhibit strong pH-dependent binding inside the cavity of a polyhedral coordination cage. Guest binding in aqueous solution is dominated by a hydrophobic contribution which is compensated by stronger solvation when the guests become cationic (by protonation) or anionic (by deprotonation). The Parkinson's drug 1-amino-adamantane ('amantadine') binds with an association constant of 10 4 M -1 in the neutral form (pH greater than 11), but the stability of the complex is reduced by three orders of magnitude when the guest is protonated at lower pH. Monitoring the uptake of the guests into the cage cavity was facilitated by the large upfield shift for the 1 H NMR signals of bound guests due to the paramagnetism of the host. Although the association constants are generally lower, guests of biological significance such as aspirin and nicotine show similar behaviour, with a substantial difference between neutral (strongly binding) and charged (weakly binding) forms, irrespective of the sign of the charged species. pH-dependent binding was observed for a range of guests with different functional groups (primary and tertiary amines, pyridine, imidazole and carboxylic acids), so that the pH-swing can be tuned anywhere in the range of 3.5-11. The structure of the adamantane-1-carboxylic acid complex was determined by X-ray crystallography: the oxygen atoms of the guest form CH···O hydrogen bonds with one of two equivalent pockets on the internal surface of the host. Reversible uptake and release of guests as a function of pH offers interesting possibilities in any application where controlled release of a molecule following an external stimulus is required.

  20. Reinvestigation of a Ru(2)-incorporated polyoxometalate dioxygenase precatalyst, "[WZnRu(2)(III)(H(2)O)(OH)(ZnW(9)O(34))(2)](11-)": evidence for marginal, (United States)

    Morris, Aimee M; Anderson, Oren P; Finke, Richard G


    A 1997 Nature paper (Nature 1997, 388, 353-355) and subsequent 1998 J. Am. Chem. Soc. paper (J. Am. Chem. Soc. 1998, 120, 11969-11976) reported that a putative Ru(2)-substituted polyoxoanion, "[WZnRu(2)(III)(H(2)O)(OH)(ZnW(9)O(34))(2)](11-)", (1), is an all inorganic dioxygenase able to incorporate one O(2) into two adamantane CH bonds to yield 2 equiv of 1-adamantanol as the primary product. In a subsequent 2005 Inorg. Chem. publication (Inorg. Chem. 2005, 44, 4175-4188), strong evidence was provided that the putative dioxygenase chemistry is, instead, the result of classic autoxidation catalysis. That research raised the question of whether the reported Ru(2) precatalyst, 1, was pure or even if it contained two Ru atoms, since Ru is known to be difficult to substitute into polyoxoanion structures (Nomiya, K.; Torii, H.; Nomura, K.; Sato, Y. J. Chem. Soc. Dalton Trans. 2001, 1506-1521). After our research group had contact with three other groups who also had difficulties reproducing the reported synthesis and composition of 1, we decided to re-examine 1 in some detail. Herein we provide evidence that the claimed 1 actually appears to be the parent polyoxoanion [WZn(3)(H(2)O)(2)(ZnW(9)O(34))(2)](12-) with small amounts of Ru (adamantane oxidation oxygen uptake and product determination studies. Also re-examined herein are the two previously reported crystal structures of 1 that appear to be very similar to the structure of the parent polyoxoanion, [WZn(3)(H(2)O)(2)(ZnW(9)O(34))(2)](12-). Furthermore, we report that trace Ru alone

  1. Epidemiological and virological characteristics of influenza viruses circulating in Cambodia from 2009 to 2011.

    Directory of Open Access Journals (Sweden)

    Srey Viseth Horm

    Full Text Available The Cambodian National Influenza Center (NIC monitored and characterized circulating influenza strains from 2009 to 2011.Sentinel and study sites collected nasopharyngeal specimens for diagnostic detection, virus isolation, antigenic characterization, sequencing and antiviral susceptibility analysis from patients who fulfilled case definitions for influenza-like illness, acute lower respiratory infections and event-based surveillance. Each year in Cambodia, influenza viruses were detected mainly from June to November, during the rainy season. Antigenic analysis show that A/H1N1pdm09 isolates belonged to the A/California/7/2009-like group. Circulating A/H3N2 strains were A/Brisbane/10/2007-like in 2009 before drifting to A/Perth/16/2009-like in 2010 and 2011. The Cambodian influenza B isolates from 2009 to 2011 all belonged to the B/Victoria lineage represented by the vaccine strains B/Brisbane/60/2008 and B/Malaysia/2506/2004. Sequences of the M2 gene obtained from representative 2009-2011 A/H3N2 and A/H1N1pdm09 strains all contained the S31N mutation associated with adamantanes resistance except for one A/H1N1pdm09 strain isolated in 2011 that lacked this mutation. No reduction in the susceptibility to neuraminidase inhibitors was observed among the influenza viruses circulating from 2009 to 2011. Phylogenetic analysis revealed that A/H3N2 strains clustered each year to a distinct group while most A/H1N1pdm09 isolates belonged to the S203T clade.In Cambodia, from 2009 to 2011, influenza activity occurred throughout the year with peak seasonality during the rainy season from June to November. Seasonal influenza epidemics were due to multiple genetically distinct viruses, even though all of the isolates were antigenically similar to the reference vaccine strains. The drug susceptibility profile of Cambodian influenza strains revealed that neuraminidase inhibitors would be the drug of choice for influenza treatment and chemoprophylaxis in Cambodia

  2. On the large σ-hyperconjugation in alkanes and alkenes. (United States)

    Wu, Judy I-Chia; Wang, Changwei; McKee, William Chadwick; Schleyer, Paul von Ragué; Wu, Wei; Mo, Yirong


    The conventional view that the σCC and σCH bonds in alkanes and unsaturated hydrocarbons are so highly localized that their non-steric interactions are negligible is scrutinized by the block-localized wavefunction (BLW) method. Even molecules considered conventionally to be "strain free" and "unperturbed" have surprisingly large and quite significant total σ-BLW-delocalization energies (DEs) due to their geminal and vicinal hyperconjugative interactions. Thus, the computed BLW-DEs (in kcal mol(-1)) for the antiperiplanar conformations of the n-alkanes (C(N)H(2N+2), N = 1-10) range from 11.6 for ethane to 82.2 for n-decane and are 50.9 for cyclohexane and 91.0 for adamantane. Although σ-electron delocalization in unsaturated hydrocarbons usually is ignored, the σ-BLW-DEs (in kcal mol(-1)) are substantial, as exemplified by D2h ethylene (9.0), triplet D2d ethylene (16.4), allene (19.3), butadiene (19.0), hexatriene (28.3), benzene (28.1), and cyclobutadiene (21.1). While each individual geminal and vicinal hyperconjugative interaction between hydrocarbon σ-bonding and σ-antibonding orbitals tends to be smaller than an individual π conjugative interaction (e.g., 10.2 kcal mol(-1) in anti-1,3-butadiene, the presence of many σ-hyperconjugative interactions (e.g., a total of 12 in anti-1,3-butadiene, see text), result in substantial total σ-stabilization energies (e.g., 19.0 kcal mol(-1) for butadiene), which may surpass those from the π interactions. Although large in magnitude, σ-electron delocalization energies often are obscured by cancellation when two hydrocarbons are compared. Rather than being strain-free, cyclohexane, adamantane, and diamantane suffer from their increasing number of intramolecular 1,4-C…C repulsions resulting in elongated C-C bond lengths and reduced σ-hyperconjugation, compared to the (skew-free) antiperiplanar n-alkane conformers. Instead of being inconsequential, σ-bond interactions are important and merit consideration.

  3. Epidemiological and Virological Characteristics of Influenza Viruses Circulating in Cambodia from 2009 to 2011 (United States)

    Ly, Sovann; Heng, Seng; Vong, Sirenda; Kitsutani, Paul; Ieng, Vannra; Tarantola, Arnaud; Ly, Sowath; Sar, Borann; Chea, Nora; Sokhal, Buth; Barr, Ian; Kelso, Anne; Horwood, Paul F.; Timmermans, Ans; Hurt, Aeron; Lon, Chanthap; Saunders, David; Ung, Sam An; Asgari, Nima; Roces, Maria Concepcion; Touch, Sok; Komadina, Naomi; Buchy, Philippe


    Background The Cambodian National Influenza Center (NIC) monitored and characterized circulating influenza strains from 2009 to 2011. Methodology/Principal Findings Sentinel and study sites collected nasopharyngeal specimens for diagnostic detection, virus isolation, antigenic characterization, sequencing and antiviral susceptibility analysis from patients who fulfilled case definitions for influenza-like illness, acute lower respiratory infections and event-based surveillance. Each year in Cambodia, influenza viruses were detected mainly from June to November, during the rainy season. Antigenic analysis show that A/H1N1pdm09 isolates belonged to the A/California/7/2009-like group. Circulating A/H3N2 strains were A/Brisbane/10/2007-like in 2009 before drifting to A/Perth/16/2009-like in 2010 and 2011. The Cambodian influenza B isolates from 2009 to 2011 all belonged to the B/Victoria lineage represented by the vaccine strains B/Brisbane/60/2008 and B/Malaysia/2506/2004. Sequences of the M2 gene obtained from representative 2009–2011 A/H3N2 and A/H1N1pdm09 strains all contained the S31N mutation associated with adamantanes resistance except for one A/H1N1pdm09 strain isolated in 2011 that lacked this mutation. No reduction in the susceptibility to neuraminidase inhibitors was observed among the influenza viruses circulating from 2009 to 2011. Phylogenetic analysis revealed that A/H3N2 strains clustered each year to a distinct group while most A/H1N1pdm09 isolates belonged to the S203T clade. Conclusions/Significance In Cambodia, from 2009 to 2011, influenza activity occurred throughout the year with peak seasonality during the rainy season from June to November. Seasonal influenza epidemics were due to multiple genetically distinct viruses, even though all of the isolates were antigenically similar to the reference vaccine strains. The drug susceptibility profile of Cambodian influenza strains revealed that neuraminidase inhibitors would be the drug of choice for

  4. Mesostructured Metal Germanium Sulfide and Selenide Materials Based on the Tetrahedral [Ge 4S 10] 4- and [Ge 4Se 10] 4- Units: Surfactant Templated Three-Dimensional Disordered Frameworks Perforated with Worm Holes (United States)

    Wachhold, Michael; Kasthuri Rangan, K.; Lei, Ming; Thorpe, M. F.; Billinge, Simon J. L.; Petkov, Valeri; Heising, Joy; Kanatzidis, Mercouri G.


    The polymerization of [Ge4S10]4- and [Ge4Se10]4- unit clusters with the divalent metal ions Zn2+, Cd2+, Hg2+, Ni2+, and Co2+ in the presence of various surfactant cations leads to novel mesostructured phases. The surfactants are the quaternary ammonium salts C12H25NMe3Br, C14H29NMe3Br, C16H33NMe3Br, and C18H37NMe3Br, which play the role of templates, helping to assemble a three-dimensional mesostructured metal-germanium chalcogenide framework. These materials are stoichiometric in nature and have the formula of (R-NMe3)2[MGe4Q10] (Q=S, Se). The local atomic structure was probed by X-ray diffuse scattering and pair distribution function analysis methods and indicates that the adamantane clusters stay intact while the linking metal atoms possess a tetrahedral coordination environment. A model can be derived, from the comparison of measured and simulated X-ray powder diffraction patterns, describing the structure as an amorphous three-dimensional framework consisting of adamantane [Ge4Q10]4- units that are bridged by tetrahedral coordinated M2+ cations. The network structures used in the simulations were derived from corresponding disordered structures developed for amorphous silicon. The frameworks in (R-NMe3)2[MGe4Q10] are perforated with worm hole-like tunnels, occupied by the surfactant cations, which show no long-range order. This motif is supported by transmission electron microscopy images of these materials. The pore sizes of these channels were estimated to lie in the range of 20-30 Å, depending on the appointed surfactant cation length. The framework wall thickness of ca. 10 Å is thereby independent from the surfactant molecules used. Up to 80% of the surfactant molecules can be removed by thermal degradation under vacuum without loss of mesostructural integrity. Physical, chemical, and spectroscopic properties of these materials are discussed.

  5. Carbon and deuterium nuclear magnetic resonance in solids

    Energy Technology Data Exchange (ETDEWEB)

    Shattuck, Thomas Wayne [Univ. of California, Berkeley, CA (United States)


    In Chapter I we present the results on a study of cross polarization dynamics, between protons and carbon-13 in adamantane, by the direct observation of the dilute, carbon-13, spins. These dynamics are an important consideration in the efficiency of proton enhancement double-resonance techniques and they also provide good experimental models for statistical theories of cross relaxation. In order to test these theories we present a comparison of the experimental and theoretical proton dipolar fluctuation correlation time τc, which is experimentally 110 ± 15 μsec and theoretically 122 μsec for adamantane. These double resonance considerations provide the background for extensions to deuterium and double quantum effects discussed in Chapter II. In Chapter II an approach to high resolution nmr of deuterium in solids is described. The m = 1 → -1 transition is excited by a double quantum process and the decay of coherence Q(τ) is monitored. Fourier transformation yields a deuterium spectrum devoid of quadrupole splittings and broadening. If the deuterium nuclei are dilute and the protons are spin decoupled, the double-quantum spectrum is a high resolution one and yields information on the deuterium chemical shifts Δω. The relationship Q(τ) ~ cos 2Δωτ is checked and the technique is applied to a single crystal of oxalic acid dihydrate enriched to ~ 10% in deuterium. The carboxyl and the water deuterium shifts are indeed resolved and the anisotropy of the carboxyl shielding tensor is estimated to be Δσ = 32 ± 3 ppm. A complete theoretical analysis is presented. The extension of cross relaxation techniques, both direct and indirect, to proton-deuterium double resonance is also described. The m = 1 → -1 double quantum transition and the m = ± 1 → 0 single quantum transitions may all be polarized and we present the derivation of the Hartmann-Hahn cross polarization conditions for each case. In addition the dynamics of the double quantum process

  6. Multidrug resistant 2009 A/H1N1 influenza clinical isolate with a neuraminidase I223R mutation retains its virulence and transmissibility in ferrets.

    Directory of Open Access Journals (Sweden)

    Erhard van der Vries


    Full Text Available Only two classes of antiviral drugs, neuraminidase inhibitors and adamantanes, are approved for prophylaxis and therapy against influenza virus infections. A major concern is that influenza virus becomes resistant to these antiviral drugs and spreads in the human population. The 2009 pandemic A/H1N1 influenza virus is naturally resistant to adamantanes. Recently a novel neuraminidase I223R mutation was identified in an A/H1N1 virus showing cross-resistance to the neuraminidase inhibitors oseltamivir, zanamivir and peramivir. However, the ability of this virus to cause disease and spread in the human population is unknown. Therefore, this clinical isolate (NL/2631-R223 was compared with a well-characterized reference virus (NL/602. In vitro experiments showed that NL/2631-I223R replicated as well as NL/602 in MDCK cells. In a ferret pathogenesis model, body weight loss was similar in animals inoculated with NL/2631-R223 or NL/602. In addition, pulmonary lesions were similar at day 4 post inoculation. However, at day 7 post inoculation, NL/2631-R223 caused milder pulmonary lesions and degree of alveolitis than NL/602. This indicated that the mutant virus was less pathogenic. Both NL/2631-R223 and a recombinant virus with a single I223R change (recNL/602-I223R, transmitted among ferrets by aerosols, despite observed attenuation of recNL/602-I223R in vitro. In conclusion, the I223R mutated virus isolate has comparable replicative ability and transmissibility, but lower pathogenicity than the reference virus based on these in vivo studies. This implies that the 2009 pandemic influenza A/H1N1 virus subtype with an isoleucine to arginine change at position 223 in the neuraminidase has the potential to spread in the human population. It is important to be vigilant for this mutation in influenza surveillance and to continue efforts to increase the arsenal of antiviral drugs to combat influenza.

  7. Octahedral [Pd6L8]12+Metallosupramolecular Cages: Synthesis, Structures and Guest-Encapsulation Studies. (United States)

    Kim, Tae Y; Digal, Lori; Gardiner, Michael G; Lucas, Nigel T; Crowley, James D


    Four planar tripyridyl ligands (L tripy ), 1,3,5-tris(pyridin-3-ylethynyl)benzene 1 a, 1,3,5-tris[4-(3-pyridyl)phenyl]benzene 2 a, and the hexyloxy chain functionalized derivatives 1,3,5-tris[(3-hexyloxy-5-pyridyl)ethynyl]benzene 1 b, and 1,3,5-tris[4-(3-hexyloxy-5-pyridyl)phenyl]benzene 2 b, were synthesized and used to generate a family of [Pd 6 (L tripy ) 8 ](BF 4 ) 12 octahedral cages (L tripy =1 a, b or 2 a, b). The ligands and cages were characterized using a combination of 1 H, 13 C, and DOSY nuclear magnetic resonance (NMR) spectroscopy, high resolution electrospray mass spectrometry (HR-ESI-MS), infrared (IR) spectroscopy, elemental analysis, and in three cases, X-ray crystallography. The molecular recognition properties of the cages with neutral and anionic guests were examined, in dimethyl sulfoxide (DMSO), using NMR spectroscopy, mass spectrometry and molecular modeling. No binding was observed with simple aliphatic and aromatic guest molecules. However, anionic sulfonates were found to interact with the octahedral cages and the binding interaction was size selective. The smaller [Pd 6 (1 a, b) 8 ] 12+ cages were able to interact with three p-toluenesulfonate guest molecules while the larger [Pd 6 (2 a, b) 8 ] 12+ systems could host four of the anionic guest molecules. To probe the importance of the hydrophobic effect, a mixed water-DMSO (1:1) solvent system was used to reexamine the binding of the neutral organic guests adamantane, anthracene, pyrene and 1,8-naphthalimide within the cages. In this solvent system all the guests except adamantane were observed to bind within the cavities of the cages. NMR spectroscopy and molecular modeling indicated that the cages bind multiple copies of the individual guests (between 3-6 guest molecules per cage). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Magnetic resonance as a structural probe of a uranium (VI) sol-gel process

    International Nuclear Information System (INIS)

    King, C.M.; Thompson, M.C.; Buchanan, B.R.; King, R.B.; Garber, A.R.


    NMR investigations on the ORNL process for sol-gel synthesis of microspherical nuclear fuel (UO 2 ), has been useful in sorting out the chemical mechanism in the sol-gel steps. 13 C, 15 N, and 1 H NMR studies on the HMTA gelation agent (Hexamethylene tetramine, C 6 H l2 N 4 ) has revealed near quantitative stability of this adamantane-like compound in the sol-Gel process, contrary to its historical role as an ammonia source for gelation from the worldwide technical literature. 17 0 NMR of uranyl (UO 2 ++ ) hydrolysis fragments produced in colloidal sols has revealed the selective formation of a uranyl trimer, [(UO 2 ) 3 (μ 3 -O)(μ 2 -OH) 3 ] + , induced by basic hydrolysis with the HMTA gelation agent. Spectroscopic results show that trimer condensation occurs during sol-gel processing leading to layered polyanionic hydrous uranium oxides in which HMTAH + is occluded as an ''intercalation'' cation. Subsequent sol-gel processing of microspheres by ammonia washing results in in-situ ion exchange and formation of a layered hydrous ammonium uranate with a proposed structural formula of (NH 4 ) 2 [(UO 2 ) 8 O 4 (OH) 10 ] · 8H 2 0. This compound is the precursor to sintered U0 2 ceramic fuel

  9. Drug Delivery and Nanoformulations for the Cardiovascular System. (United States)

    Geldenhuys, W J; Khayat, M T; Yun, J; Nayeem, M A


    Therapeutic delivery to the cardiovascular system may play an important role in the successful treatment of a variety of disease state, including atherosclerosis, ischemic-reperfusion injury and other types of microvascular diseases including hypertension. In this review we evaluate the different options available for the development of suitable delivery systems that include the delivery of small organic compounds [adenosin A 2A receptor agonist (CGS 21680), CYP-epoxygenases inhibitor (N-(methylsulfonyl)-2-(2-propynyloxy)-benzenehexanamide, trans-4-[4-(3-adamantan-1-ylureido)cyclohexyloxy] benzoic acid), soluble epoxide hydrolase inhibitor (N-methylsulfonyl-12,12-dibromododec-11-enamide), PPARγ agonist (rosiglitazone) and PPARγ antagonist (T0070907)], nanoparticles, peptides, and siRNA to the cardiovascular system. Effective formulations of nanoproducts have significant potential to overcome physiological barriers and improve therapeutic outcomes in patients. As per the literature covering targeted delivery to the cardiovascular system, we found that this area is still at infancy stage, as compare to the more mature fields of tumor cancer or brain delivery (e.g. blood-brain barrier permeability) with fewer publications focused on the targeted drug delivery technologies. Additionally, we show how pharmacology needs to be well understood when considering the cardiovascular system. Therefore, we discussed in this review various receptors agonists, antagonists, activators and inhibitors which will have effects on cardiovascular system.

  10. Preventing drug resistance in severe influenza (United States)

    Dobrovolny, Hana; Deecke, Lucas


    Severe, long-lasting influenza infections are often caused by new strains of influenza. The long duration of these infections leads to an increased opportunity for the emergence of drug resistant mutants. This is particularly problematic for new strains of influenza since there is often no vaccine, so drug treatment is the first line of defense. One strategy for trying to minimize drug resistance is to apply periodic treatment. During treatment the wild-type virus decreases, but resistant virus might increase; when there is no treatment, wild-type virus will hopefully out-compete the resistant virus, driving down the number of resistant virus. We combine a mathematical model of severe influenza with a model of drug resistance to study emergence of drug resistance during a long-lasting infection. We apply periodic treatment with two types of antivirals: neuraminidase inhibitors, which block release of virions; and adamantanes, which block replication of virions. We compare the efficacy of the two drugs in reducing emergence of drug resistant mutants and examine the effect of treatment frequency on the emergence of drug resistant mutants.

  11. Diamondoid Hydrocarbons as Maturity Indicators for Condensates from Southern Indus Basin, Pakistan

    Directory of Open Access Journals (Sweden)

    Shagufta Nasir


    Full Text Available Diamondoid hydrocarbons have been examined in condensates reservoired in the Southern Indus Basin using GC-MS. Bulk properties reveal that samples are waxy and low sulfur with the exception of Pakhro and Gopang which are nonwaxy. TIC show bimodal distribution of n-alkanes along with high abundance of C20+ n-alkanes indicating substantial contribution of terrigeneous OM in these samples. CPI close to one is consistent with mature nature of oils. The samples show two ranges of Pr/Ph ratios. Those within the range of 2.2–2.7 reflect marine depositional settings for OM while others with Pr/Ph >3 may have originated from terrestrial OM deposited under marine oxic conditions. The cross plot of Pr/n-C17 versus Ph/n-C18 indicate type III kerogen as main source of OM deposited under marine to marine oxic conditions. The values of diamondoid based maturity parameters, like methyladamantane index 54.1–75.8% and methyldiamantane index 34.9–56.3% indicate high level of thermal maturity corresponding to vitrinite reflectance 1.1–1.6%. No biodegradation is observed in any of these samples as shown by methyladamantanes/adamantane 3.99–5.52 and methyldiamantanes/diamantane 2.16–2.99 and supported by high values of API gravity (45.13°–60.02° and absence of UCM.

  12. Complex and surprising VOC chemistry in oil and gas producing regions: H3O+ CIMS results from the SONGNEX 2015 aircraft mission (United States)

    Koss, A.; Yuan, B.; Warneke, C.; Gilman, J.; Lerner, B. M.; Veres, P. R.; Eilerman, S. J.; Peischl, J.; Wild, R. J.; Brown, S. S.; Thompson, C. R.; Ryerson, T. B.; Hanisco, T. F.; Wolfe, G. M.; St Clair, J. M.; Thayer, M. P.; Keutsch, F. N.; Murphy, S. M.; De Gouw, J. A.


    VOCs emitted from oil and natural gas extraction operations can significantly affect local and regional air quality. During the SONGNEX 2015 mission aboard NOAA's P3 Orion aircraft, which surveyed a number of major oil and gas producing regions in the United States, VOCs and several inorganic compounds were characterized using high-resolution time-of-flight H3O+ CIMS (similar to PTR-ToF). Here we present an overview and comparison of air toxics in nine basins, and a more detailed view of VOCs in the Permian Basin (TX/NM). In many basins, mixing ratios of aromatics were frequently as high as those measured downwind of large urban areas. High concentrations of methanol were also consistently observed. Hydrogen sulfide (H2S) was observed in a limited number of locations, and we suggest some likely sources. The Permian basin had the highest overall concentrations of measured VOCs. Several unexpected and underreported species were also detected, including aromatic and cycloalkane oxidation products, nitrogen heterocycles, and potentially a diamondoid compound (adamantane). This work highlights the challenges of interpreting PTR-MS data in oil and gas-producing regions, and suggests that there may be VOCs in these regions important to atmospheric chemistry that are not currently measurement targets.

  13. Crystal structure of CuFeInSe{sub 3} from X-ray powder diffraction data

    Energy Technology Data Exchange (ETDEWEB)

    Mora, Asiloe J.; Delgado, Gerzon E. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Grima-Gallardo, Pedro [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela)


    The crystal structure of the adamantane compound CuFeInSe{sub 3}, belonging to the system (CuInSe{sub 2}){sub 1-x}(FeSe){sub x} with x=0.5, was analyzed using X-ray powder diffraction data. Several model structures were derived from the structure of the selenium rich phase CuInSe{sub 2.3} by permuting the cations in the available Wyckoff positions. The refinement of the best model by the Rietveld method in the tetragonal space group P anti 42c (N 112), Z=1, with unit cell parameters a=5.7762(2) Aa, c=11.5982(7) Aa and V=386.97(3) Aa{sup 3} led to R{sub p}=8.0%, R{sub wp}=9.6%, R{sub exp}=6.2% and {chi}{sup 2}=1.7 for 134 independent reflections. The model that best fitted the diffraction data has the following atomic distribution: Cu in Wyckoff site 2f; Fe in Wyckoff site 2d; In in Wyckoff site 2b and 1/3Cu, 1/3Fe, 1/3In in Wyckoff site 2f; Se in Wyckoff site 8n. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Composition of the Essential Oil of Aristolochia Manshurientsis Kom (United States)

    Zhao, Xiuhong; Xin, Guang; Zhao, Lichun; Xiao, Zhigang; Xue, Bai


    This study demonstrated the chemical constituents of the essential oil of Aristolochia manshurientsis Kom and improved the essential oil efficiency by the enzyme-assisted extraction followed by hydrodistillation. The essential oils of Aristolochia manshurientsis Kom acquired by hydrodistillation after the solvent extraction with and without the assistance of cellulase have been investigated by gas chromatography/Mass spectrometry (GC-MS). The predominant constituents of both types of essential oils are camphene, 1,7,7-trimethyl-bicyclo [2.2.1] hept-2-yl acetate, 1,6-dimethyl-4-(1-methylethyl) naphthalene, caryophyllene oxide, borneol, and (-)-Spathulenol. The enzyme-assisted extraction not only increased extracting efficiency of the essential oil from 4.93% to 9.36%, but also facilitated the extraction of additional eight compounds such as 2-methano(-6,6-dimethyl) bicycle [3.1.1] hept-2-ene, (+)--terpineol and 1-propyl-3-(propen-1-yl) adamantane, which were not identified from the non-enzyme extraction sample.

  15. [Fe(III)(F(20)-tpp)Cl] is an effective catalyst for nitrene transfer reactions and amination of saturated hydrocarbons with sulfonyl and aryl azides as nitrogen source under thermal and microwave-assisted conditions. (United States)

    Liu, Yungen; Che, Chi-Ming


    [Fe(III)(F(20)-tpp)Cl] (F(20)-tpp=meso-tetrakis(pentafluorophenyl)porphyrinato dianion) is an effective catalyst for imido/nitrene insertion reactions using sulfonyl and aryl azides as nitrogen source. Under thermal conditions, aziridination of aryl and alkyl alkenes (16 examples, 60-95 % yields), sulfimidation of sulfides (11 examples, 76-96 % yields), allylic amidation/amination of α-methylstyrenes (15 examples, 68-83 % yields), and amination of saturated C--H bonds including that of cycloalkanes and adamantane (eight examples, 64-80 % yields) can be accomplished by using 2 mol % [Fe(III)(F(20)-tpp)Cl] as catalyst. Under microwave irradiation conditions, the reaction time of aziridination (four examples), allylic amination (five examples), sulfimidation (two examples), and amination of saturated C--H bonds (three examples) can be reduced by up to 16-fold (24-48 versus 1.5-6 h) without significantly affecting the product yield and substrate conversion.

  16. Massively parallel and linear-scaling algorithm for second-order Møller-Plesset perturbation theory applied to the study of supramolecular wires (United States)

    Kjærgaard, Thomas; Baudin, Pablo; Bykov, Dmytro; Eriksen, Janus Juul; Ettenhuber, Patrick; Kristensen, Kasper; Larkin, Jeff; Liakh, Dmitry; Pawłowski, Filip; Vose, Aaron; Wang, Yang Min; Jørgensen, Poul


    We present a scalable cross-platform hybrid MPI/OpenMP/OpenACC implementation of the Divide-Expand-Consolidate (DEC) formalism with portable performance on heterogeneous HPC architectures. The Divide-Expand-Consolidate formalism is designed to reduce the steep computational scaling of conventional many-body methods employed in electronic structure theory to linear scaling, while providing a simple mechanism for controlling the error introduced by this approximation. Our massively parallel implementation of this general scheme has three levels of parallelism, being a hybrid of the loosely coupled task-based parallelization approach and the conventional MPI +X programming model, where X is either OpenMP or OpenACC. We demonstrate strong and weak scalability of this implementation on heterogeneous HPC systems, namely on the GPU-based Cray XK7 Titan supercomputer at the Oak Ridge National Laboratory. Using the "resolution of the identity second-order Møller-Plesset perturbation theory" (RI-MP2) as the physical model for simulating correlated electron motion, the linear-scaling DEC implementation is applied to 1-aza-adamantane-trione (AAT) supramolecular wires containing up to 40 monomers (2440 atoms, 6800 correlated electrons, 24 440 basis functions and 91 280 auxiliary functions). This represents the largest molecular system treated at the MP2 level of theory, demonstrating an efficient removal of the scaling wall pertinent to conventional quantum many-body methods.

  17. A 3D Covalent Organic Framework with Exceptionally High Iodine Capture Capability. (United States)

    Wang, Chang; Wang, Yu; Ge, Rile; Song, Xuedan; Xing, Xueqing; Jiang, Qike; Lu, Hui; Hao, Ce; Guo, Xinwen; Gao, Yanan; Jiang, Donglin


    Using porous materials to cope with environmental issues is promising but remains a challenge especially for removing the radioactive vapor wastes in fission because of harsh adsorption conditions. Here we report a new, stable covalent organic framework (COF) as a porous platform for removing iodine vapor-a major radioactive fission waste. The three-dimensional COF consists of a diamond topology knotted by adamantane units, creates ordered one-dimensional pores and are highly porous. The COF enables the removal of iodine vapor via charge transfer complex formation with the pore walls to achieve exceptional capacity. Moreover, the 3D COF is "soft" to trigger structural fitting to iodine while retaining connectivity and enables cycle use for many times while retaining high uptake capacity. These results set a new benchmark for fission waste removal and suggest the great potential of COFs as a designable porous material for challenging world-threatening pollution issues. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Optical Properties of Single- and Double-Functionalized Small Diamondoids. (United States)

    Sarap, Chandra Shekar; Adhikari, Bibek; Meng, Sheng; Uhlig, Frank; Fyta, Maria


    The rational control of the electronic and optical properties of small functionalized diamond-like molecules, the diamondoids, is the focus of this work. Specifically, we investigate the single- and double- functionalization of the lower diamondoids, adamantane, diamantane, and triamantane with -NH 2 and -SH groups and extend the study to N-heterocyclic carbene (NHC) functionalization. On the basis of electronic structure calculations, we predict a significant change in the optical properties of these functionalized diamondoids. Our computations reveal that -NH 2 functionalized diamondoids show UV photoluminescence similar to ideal diamondoids while -SH substituted diamondoids hinder the UV photoluminescence due to the labile nature of the S-H bond in the first excited state. This study also unveils that the UV photoluminescence nature of -NH 2 diamondoids is quenched upon additional functionalization with the -SH group. The double-functionalized derivative can, thus, serve as a sensitive probe for biomolecule binding and sensing environmental changes. The preserved intrinsic properties of the NHC and the ideal diamondoid in NHC-functionalized-diamondoids suggests its utilization in diamondoid-based self-assembled monolayers (SAM), whose UV-photoluminescent signal would be determined entirely by the functionalized diamondoids. Our study aims to pave the path for tuning the properties of diamondoids through a selective choice of the type and number of functional groups. This will aid the realization of optoelectronic devices involving, for example, large-area SAM layers or diamondoid-functionalized electrodes.

  19. Enhancing Moisture and Water Resistance in Perovskite Solar Cells by Encapsulation with Ultrathin Plasma Polymers. (United States)

    Idígoras, Jesús; Aparicio, Francisco J; Contreras-Bernal, Lidia; Ramos-Terrón, Susana; Alcaire, María; Sánchez-Valencia, Juan Ramón; Borras, Ana; Barranco, Ángel; Anta, Juan A


    A compromise between high power conversion efficiency and long-term stability of hybrid organic-inorganic metal halide perovskite solar cells is necessary for their outdoor photovoltaic application and commercialization. Herein, a method to improve the stability of perovskite solar cells under water and moisture exposure consisting of the encapsulation of the cell with an ultrathin plasma polymer is reported. The deposition of the polymer is carried out at room temperature by the remote plasma vacuum deposition of adamantane powder. This encapsulation method does not affect the photovoltaic performance of the tested devices and is virtually compatible with any device configuration independent of the chemical composition. After 30 days under ambient conditions with a relative humidity (RH) in the range of 35-60%, the absorbance of encapsulated perovskite films remains practically unaltered. The deterioration in the photovoltaic performance of the corresponding encapsulated devices also becomes significantly delayed with respect to devices without encapsulation when vented continuously with very humid air (RH > 85%). More impressively, when encapsulated solar devices were immersed in liquid water, the photovoltaic performance was not affected at least within the first 60 s. In fact, it has been possible to measure the power conversion efficiency of encapsulated devices under operation in water. The proposed method opens up a new promising strategy to develop stable photovoltaic and photocatalytic perovskite devices.

  20. Osmotic stress regulates the strength and kinetics of sugar binding to the maltoporin channel. (United States)

    Gurnev, Philip A; Harries, Daniel; Parsegian, V Adrian; Bezrukov, Sergey M


    We study the effect of osmotic stress, exerted by salts, on carbohydrate binding to the sugar-specific bacterial channel maltoporin. When the channel is reconstituted into planar lipid bilayers, single events of its occlusion by sugar are seen as transient interruptions in the flow of small ions. We find that, for most salts, changes in the free energy of maltoporin-sugar binding vary linearly with solution osmotic pressure. Such a change in binding with solution osmolarity indicates that for each salt a constant number of salt-excluding water molecules is released upon sugar-maltoporin association at all salt concentrations. We find that larger numbers of water molecules are released upon binding of the cyclic carbohydrate β-cyclodextrin (CD) than upon binding of the corresponding linear homologue maltoheptaose (m7). Remarkably, the extent to which salts affect the binding constants and rates depends sensitively on the type of salt; dehydration in solutions of different anions corresponds to the Hofmeister series. In sodium sulfate solutions, CD and m7 respectively release about 120 and 35 salt-excluding water molecules; in sodium chloride solutions, 35 and 15 waters. No water release is observed with sodium bromide. Finally, by adding adamantane, known to form an inclusion complex with CD, we can infer that CD not only dehydrates but also undergoes a conformational change upon binding to the channel. As a practical outcome, our results also demonstrate how osmotic stress can improve single-molecule detection of different solutes using protein-based nanopores.

  1. 1H Solid-State NMR Imaging by TREV-CRAMPS (United States)

    Buszko, M. L.; Maciel, G. E.

    A proton NMR imaging experiment based on line narrowing by TREV-CRAMPS with a time-dependent magnetic field gradient has been demonstrated on a solid adamantane phantom. With the magnetic field gradient applied as 16 μs pulses in the windows of the RF pulse sequence, a spatial resolution of about 100 μm is experimentally achieved (based on linewidth and gradient strength), with a digital resolution of 40 μm, qualitatively similar to what is achieved in liquid-sample NMR imaging. The technique benefits from a favorable time average of the magnetic field gradient, relatively wide windows between the magic-echo sandwiches, and the good off-resonance line-narrowing characteristics of the TREV technique. High-resolution chemical-shift information is retained and hence potentially attainable. The low MAS rate, compared to what is used in imaging experiments in which MAS is the only line-narrowing procedure used, may be of importance if one wishes to apply 1H NMR imaging to certain types of samples, e.g., biological tissue.

  2. Design and Construction of a Smart Targeting Drug Delivery System Based on Phototriggered Competition of Host-Guest Interaction. (United States)

    Zhao, Dan; Yi, Xiaoqing; Yuan, Gongdao; Zhuo, Renxi; Li, Feng


    A smart targeting drug delivery nanocarrier is successfully constructed based on phototriggered competition of host-guest interaction. The targeting motif, i.e., biotin is first concealed by β-cyclodextrin (β-CD) via host-guest interaction. When the nanoparticles are exposed to UV light, the cleavage of photosensitive groups results in the exposure of adamantane (Ad) groups initially located in the interior of nanoassemblies, and β-CDs capped on biotin ligands can be replaced by Ad because of the higher binding constant between Ad and β-CD than that between biotin and β-CD. The competition of host-guest interaction leads to the recovery of targeting capacity of biotin ligands on the nanocarriers. By virtue of photoregulation, the nanocarriers exhibit controllable ligand-receptor recognition, which is proved by flow cytometry, laser confocal microscopy, and cytotoxicity assay. This strategy has a potential to improve the selectivity and safety of targeting drug delivery systems. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Spectroscopic study of the reaction of silver atoms with CO in a rotating cryostat

    Energy Technology Data Exchange (ETDEWEB)

    Chenier, J.H.B.; Hampson, C.A.; Howard, J.A.; Mile, B.


    Reactions of /sup 107/Ag atoms with CO have been studied in inert hydrocarbon matrices in a rotating cryostat at cryogenic temperatures by EPR and FTIR spectroscopies. AgCO, bent Ag(CO)/sub 2/ two conformers of Ag(CO)/sub 3/, and cluster carbonyls Ag/sub n/(CO)/sub x/, where n greater than or equal to 5, are formed in adamantane. Magnetic parameters are reported for these silver carbonyls. IR spectra show the presence of a range of carbon monoxide complexes with single Ag atoms and Ag clusters, but the considerable overlapping of the bands from all these species precludes assignment other than that at 1952 cm/sup -1/ to planar Ag(CO)/sub 3/. In cyclohexane unambiguous EPR or FTIR evidence for mononuclear AG carbonyls is not obtained, but there are strong complex features in both spectra from a range of Ag cluster carbonyls AG/sub n/(CO)/sub x/ with n = 2-7.

  4. Binding Cellulose and Chitosan via Intermolecular Inclusion Interaction: Synthesis and Characterisation of Gel

    Directory of Open Access Journals (Sweden)

    Jiufang Duan


    Full Text Available A novel cellulose-chitosan gel was successfully prepared in three steps: (1 ferrocene- (Fc- cellulose with degrees of substitution (DS of 0.5 wt% was synthesised by ferrocenecarboxylic acid and cellulose within dimethylacetamide/lithium chloride (DMAc/LiCl; (2 the β-cyclodextrin (β-CD groups were introduced onto the chitosan chains by reacting chitosan with epichlorohydrin in dimethyl sulphoxide and a DS of 0.35 wt%; (3 thus, the cellulose-chitosan gel was obtained via an intermolecular inclusion interaction of Fc-cellulose and β-CD-chitosan in DMA/LiCl, that is, by an intermolecular inclusion interaction, between the Fc groups of cellulose and the β-CD groups on the chitosan backbone at room temperature. The successful synthesis of Fc-cellulose and β-CD-chitosan was characterised by 13C-NMR spectroscopy. The gel based on β-CD-chitosan and Fc-cellulose was formed under mild conditions which can engender autonomous healing between cut surfaces after 24 hours: the gel cannot self-heal while the cut surfaces were coated with a solution of a competitive guest (adamantane acid. The cellulose-chitosan complex made by this method underwent self-healing. Therefore, this study provided a novel method of expanding the application of chitosan by binding it with another polymer.

  5. Advances in the Development of PET Ligands Targeting Histone Deacetylases for the Assessment of Neurodegenerative Diseases

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    Tetsuro Tago


    Full Text Available Epigenetic alterations of gene expression have emerged as a key factor in several neurodegenerative diseases. In particular, inhibitors targeting histone deacetylases (HDACs, which are enzymes responsible for deacetylation of histones and other proteins, show therapeutic effects in animal neurodegenerative disease models. However, the details of the interaction between changes in HDAC levels in the brain and disease progression remain unknown. In this review, we focus on recent advances in development of radioligands for HDAC imaging in the brain with positron emission tomography (PET. We summarize the results of radiosynthesis and biological evaluation of the HDAC ligands to identify their successful results and challenges. Since 2006, several small molecules that are radiolabeled with a radioisotope such as carbon-11 or fluorine-18 have been developed and evaluated using various assays including in vitro HDAC binding assays and PET imaging in rodents and non-human primates. Although most compounds do not readily cross the blood-brain barrier, adamantane-conjugated radioligands tend to show good brain uptake. Until now, only one HDAC radioligand has been tested clinically in a brain PET study. Further PET imaging studies to clarify age-related and disease-related changes in HDACs in disease models and humans will increase our understanding of the roles of HDACs in neurodegenerative diseases.

  6. Experimental infection of H5N1 HPAI in BALB/c mice

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    Ignatyev George M


    Full Text Available Abstract Background In 2005 huge epizooty of H5N1 HPAI occurred in Russia. It had been clear that territory of Russia becoming endemic for H5N1 HPAI. In 2006 several outbreaks have occurred. To develop new vaccines and antiviral therapies, animal models had to be investigated. We choose highly pathogenic strain for these studies. Results A/duck/Tuva/01/06 belongs to Quinghai-like group viruses. Molecular markers – cleavage site, K627 in PB2 characterize this virus as highly pathogenic. This data was confirmed by direct pathogenic tests: IVPI = 3.0, MLD50 = 1,4Log10EID50. Also molecular analysis showed sensivity of the virus to adamantanes and neuraminidase inhibitors. Serological analysis showed wide cross-reactivity of this virus with sera produced to H5N1 HPAI viruses isolated earlier in South-East Asia. Mean time to death of infected animals was 8,19+/-0,18 days. First time acute delayed hemorrhagic syndrome was observed in mice lethal model. Hypercytokinemia was determined by elevated sera levels of IFN-gamma, IL-6, IL-10. Conclusion Assuming all obtained data we can conclude that basic model parameters were characterized and virus A/duck/Tuva/01/06 can be used to evaluate anti-influenza vaccines and therapeutics.

  7. Pharmaceuticals that contain polycyclic hydrocarbon scaffolds. (United States)

    Stockdale, Tegan P; Williams, Craig M


    Numerous variations on structural motifs exist within pharmaceutical compounds that have entered the clinic. These variations have amounted over many decades based on years of drug development associated with screening natural products and de novo synthetic systems. Caged (or bridged) bicyclic structural elements offer a variety of diverse features, encompassing three-dimensional shape, and assorted pharmacokinetic properties. This review highlights approximately 20 all carbon cage containing pharmaceuticals, ranging in structure from bicyclo[2.2.1] through to adamantane, including some in the top-selling pharmaceutical bracket. Although, a wide variety of human diseases, illnesses and conditions are treated with drugs containing the bicyclic motif, a common feature is that many of these lipophilic systems display CNS and/or neurological activity. In addition, to an extensive overview of the history and biology associated with each drug, a survey of synthetic methods used to construct these entities is presented. An analysis section compares natural products to synthetics in drug discovery, and entertains the classical caged hydrocarbon systems potentially missing from the clinic. Lastly, this unprecedented review is highly pertinent at a time when big pharma is desperately trying to escape flatland drugs.

  8. Near-Edge X-ray Absorption Fine Structure Spectroscopy of Diamondoid Thiol Monolayers on Gold

    Energy Technology Data Exchange (ETDEWEB)

    Willey, T M; Fabbri, J; Lee, J I; Schreiner, P; Fokin, A A; Tkachenko, B A; Fokina, N A; Dahl, J; Carlson, B; Vance, A L; Yang, W; Terminello, L J; van Buuren, T; Melosh, N


    Diamondoids, hydrocarbon molecules with cubic-diamond-cage structures, have unique properties with potential value for nanotechnology. The availability and ability to selectively functionalize this special class of nanodiamond materials opens new possibilities for surface-modification, for high-efficiency field emitters in molecular electronics, as seed crystals for diamond growth, or as robust mechanical coatings. The properties of self-assembled monolayers (SAMs) of diamondoids are thus of fundamental interest for a variety of emerging applications. This paper presents the effects of thiol substitution position and polymantane order on diamondoid SAMs on gold using near-edge X-ray absorption fine structure spectroscopy (NEXAFS) and X-ray photoelectron spectroscopy (XPS). A framework to determine both molecular tilt and twist through NEXAFS is presented and reveals highly ordered diamondoid SAMs, with the molecular orientation controlled by the thiol location. C 1s and S 2p binding energies are lower in adamantane thiol than alkane thiols on gold by 0.67 {+-} 0.05 eV and 0.16 {+-} 0.04 eV respectively. These binding energies vary with diamondoid monolayer structure and thiol substitution position, consistent with different amounts of steric strain and electronic interaction with the substrate. This work demonstrates control over the assembly, in particular the orientational and electronic structure, providing a flexible design of surface properties with this exciting new class of diamond clusters.

  9. Nanodiamonds in sugar rings: an experimental and theoretical investigation of cyclodextrin-nanodiamond inclusion complexes. (United States)

    Voskuhl, Jens; Waller, Mark; Bandaru, Sateesh; Tkachenko, Boryslav A; Fregonese, Carlo; Wibbeling, Birgit; Schreiner, Peter R; Ravoo, Bart Jan


    We report on the noncovalent interactions of nanodiamond carboxylic acids derived from adamantane, diamantane, and triamantane with β- and γ-cyclodextrins. The water solubility of the nanodiamonds was increased by attaching an aromatic dicarboxylic acid via peptide coupling. Isothermal titration calorimetry experiments were performed to determine the thermodynamic parameters (K(a), ΔH, ΔG and ΔS) for the host-guest inclusion. The stoichiometry of the complexes is invariably 1:1. It was found that K(a), ΔG and ΔH of inclusion increase for larger nanodiamonds. ΔS is generally positive, in particular for the largest nanodiamonds. β-Cyclodextrin binds all nanodiamonds, γ-cyclodextrin clearly prefers the most bulky nanodiamonds. The interaction of 9-triamantane carboxylic acid shows one of the strongest complexation constants towards γ-cyclodextrin ever reported, K(a) = 5.0 × 10(5) M(-1). In order to gain some insight into the possible structural basis of these inclusion complexes we performed density functional calculations at the B97-D3/def2-TZVPP level of theory.

  10. Oseltamivir-resistant pandemic (H1N12009 in Yemen - case report

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    Al-Kohlani Abdulhakeem


    Full Text Available Abstract Background During the influenza season of 2007-08, oseltamivir-resistant influenza A (H1N1 viruses emerged in several countries in Europe, North America, and Asia. Despite substantial prevalence of oseltamivir-resistant viruses, few data are available on the clinical profile of subjects infected with these viruses. Objectives: to describe the first oseltamivir-resistant (H1N1 influenza virus pandemic 2009 from the Eastern Mediterranean Region including Yemen and to determine the evidence by clinical presentation of children infected with these oseltamivir - resistant viruses. Methodology History, physical examination and laboratory investigations including Complete Blood Count, chest x-ray, blood cultures, CSF examination, LFTs, RFTs, blood for sugar, H1N1 test and oseltamivir resistance test. Results Nasal swabs indicated positivity on both H1N1 test and the RNP gene (Human R Nase P gene that serves as internal positive control for Human RNA. Both clinical specimens presented the mutation S31N in the M2 gene associated with resistance to adamantanes and H274Y in NA gene associated with resistance to oseltamivir. This was the first diagnosed case of resistance to oseltamivir in Yemen and also it is the first reported case of oseltamivir resistance virus in the Eastern Mediterranean Region. Conclusion The pattern of resistance found in the oseltamivir resistant isolate collected from Yemen is the same as has been reported elsewhere in other WHO regions. Clinical description and outcomes are not different from what is described elsewhere.

  11. Osmotic stress regulates the strength and kinetics of sugar binding to the maltoporin channel

    International Nuclear Information System (INIS)

    Gurnev, Philip A; Bezrukov, Sergey M; Harries, Daniel; Adrian Parsegian, V


    We study the effect of osmotic stress, exerted by salts, on carbohydrate binding to the sugar-specific bacterial channel maltoporin. When the channel is reconstituted into planar lipid bilayers, single events of its occlusion by sugar are seen as transient interruptions in the flow of small ions. We find that, for most salts, changes in the free energy of maltoporin-sugar binding vary linearly with solution osmotic pressure. Such a change in binding with solution osmolarity indicates that for each salt a constant number of salt-excluding water molecules is released upon sugar-maltoporin association at all salt concentrations. We find that larger numbers of water molecules are released upon binding of the cyclic carbohydrate β-cyclodextrin (CD) than upon binding of the corresponding linear homologue maltoheptaose (m7). Remarkably, the extent to which salts affect the binding constants and rates depends sensitively on the type of salt; dehydration in solutions of different anions corresponds to the Hofmeister series. In sodium sulfate solutions, CD and m7 respectively release about 120 and 35 salt-excluding water molecules; in sodium chloride solutions, 35 and 15 waters. No water release is observed with sodium bromide. Finally, by adding adamantane, known to form an inclusion complex with CD, we can infer that CD not only dehydrates but also undergoes a conformational change upon binding to the channel. As a practical outcome, our results also demonstrate how osmotic stress can improve single-molecule detection of different solutes using protein-based nanopores.

  12. 2-(1-Adamant-yl)-1-{4-[(2-chloro-9-isopropyl-9H-purin-6-yl)amino-meth-yl]phen-yl}ethanone. (United States)

    Rouchal, Michal; Nečas, Marek; de Carvalho, Fabiana Pires; Vícha, Robert


    The structure of the title compound, C(27)H(32)ClN(5)O, consists of two crystallographically independent conformers differing slightly in all geometric parameters. Both contain nearly planar purine and benzene ring systems [maximum deviations of 0.046 (3) and 0.005 (2) Å, respectively], the dihedral angles between them being 76.44 (6) and 82.39 (6)°, and an adamantane cage consisting of three fused cyclo-hexane rings in almost ideal chair conformations, with C-C-C angles in the range 108.7 (2)-110.6 (2)°. The carbonyl plane and the benzene ring are almost coplanar [dihedral angles of 6.43 (9) and 0.64 (8)° in the two conformers]. The crystal structure is stabilized by inter-molecular N-H⋯N inter-actions that link adjacent mol-ecules into dimers and by some non-bonding contacts of the C-H⋯Cl type.

  13. 2-(1-Adamantyl-1-{4-[(2-chloro-9-isopropyl-9H-purin-6-ylaminomethyl]phenyl}ethanone

    Directory of Open Access Journals (Sweden)

    Robert Vícha


    Full Text Available The structure of the title compound, C27H32ClN5O, consists of two crystallographically independent conformers differing slightly in all geometric parameters. Both contain nearly planar purine and benzene ring systems [maximum deviations of 0.046 (3 and 0.005 (2 Å, respectively], the dihedral angles between them being 76.44 (6 and 82.39 (6°, and an adamantane cage consisting of three fused cyclohexane rings in almost ideal chair conformations, with C—C—C angles in the range 108.7 (2–110.6 (2°. The carbonyl plane and the benzene ring are almost coplanar [dihedral angles of 6.43 (9 and 0.64 (8° in the two conformers]. The crystal structure is stabilized by intermolecular N—H...N interactions that link adjacent molecules into dimers and by some non-bonding contacts of the C—H...Cl type.

  14. Observations of VOC emissions and photochemical products over US oil- and gas-producing regions using high-resolution H3O+ CIMS (PTR-ToF-MS

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    A. Koss


    Full Text Available VOCs related to oil and gas extraction operations in the United States were measured by H3O+ chemical ionization time-of-flight mass spectrometry (H3O+ ToF-CIMS/PTR-ToF-MS from aircraft during the Shale Oil and Natural Gas Nexus (SONGNEX campaign in March–April 2015. This work presents an overview of major VOC species measured in nine oil- and gas-producing regions, and a more detailed analysis of H3O+ ToF-CIMS measurements in the Permian Basin within Texas and New Mexico. Mass spectra are dominated by small photochemically produced oxygenates and compounds typically found in crude oil: aromatics, cyclic alkanes, and alkanes. Mixing ratios of aromatics were frequently as high as those measured downwind of large urban areas. In the Permian, the H3O+ ToF-CIMS measured a number of underexplored or previously unreported species, including aromatic and cycloalkane oxidation products, nitrogen heterocycles including pyrrole (C4H5N and pyrroline (C4H7N, H2S, and a diamondoid (adamantane or unusual monoterpene. We additionally assess the specificity of a number of ion masses resulting from H3O+ ion chemistry previously reported in the literature, including several new or alternate interpretations.

  15. Observations of VOC emissions and photochemical products over US oil- and gas-producing regions using high-resolution H3O+ CIMS (PTR-ToF-MS) (United States)

    Koss, Abigail; Yuan, Bin; Warneke, Carsten; Gilman, Jessica B.; Lerner, Brian M.; Veres, Patrick R.; Peischl, Jeff; Eilerman, Scott; Wild, Rob; Brown, Steven S.; Thompson, Chelsea R.; Ryerson, Thomas; Hanisco, Thomas; Wolfe, Glenn M.; St. Clair, Jason M.; Thayer, Mitchell; Keutsch, Frank N.; Murphy, Shane; de Gouw, Joost


    VOCs related to oil and gas extraction operations in the United States were measured by H3O+ chemical ionization time-of-flight mass spectrometry (H3O+ ToF-CIMS/PTR-ToF-MS) from aircraft during the Shale Oil and Natural Gas Nexus (SONGNEX) campaign in March-April 2015. This work presents an overview of major VOC species measured in nine oil- and gas-producing regions, and a more detailed analysis of H3O+ ToF-CIMS measurements in the Permian Basin within Texas and New Mexico. Mass spectra are dominated by small photochemically produced oxygenates and compounds typically found in crude oil: aromatics, cyclic alkanes, and alkanes. Mixing ratios of aromatics were frequently as high as those measured downwind of large urban areas. In the Permian, the H3O+ ToF-CIMS measured a number of underexplored or previously unreported species, including aromatic and cycloalkane oxidation products, nitrogen heterocycles including pyrrole (C4H5N) and pyrroline (C4H7N), H2S, and a diamondoid (adamantane) or unusual monoterpene. We additionally assess the specificity of a number of ion masses resulting from H3O+ ion chemistry previously reported in the literature, including several new or alternate interpretations.

  16. Osmotic stress regulates the strength and kinetics of sugar binding to the maltoporin channel (United States)

    Gurnev, Philip A.; Harries, Daniel; Parsegian, V. Adrian; Bezrukov, Sergey M.


    We study the effect of osmotic stress, exerted by salts, on carbohydrate binding to the sugar-specific bacterial channel maltoporin. When the channel is reconstituted into planar lipid bilayers, single events of its occlusion by sugar are seen as transient interruptions in the flow of small ions. We find that, for most salts, changes in the free energy of maltoporin-sugar binding vary linearly with solution osmotic pressure. Such a change in binding with solution osmolarity indicates that for each salt a constant number of salt-excluding water molecules is released upon sugar-maltoporin association at all salt concentrations. We find that larger numbers of water molecules are released upon binding of the cyclic carbohydrate β-cyclodextrin (CD) than upon binding of the corresponding linear homologue maltoheptaose (m7). Remarkably, the extent to which salts affect the binding constants and rates depends sensitively on the type of salt; dehydration in solutions of different anions corresponds to the Hofmeister series. In sodium sulfate solutions, CD and m7 respectively release about 120 and 35 salt-excluding water molecules; in sodium chloride solutions, 35 and 15 waters. No water release is observed with sodium bromide. Finally, by adding adamantane, known to form an inclusion complex with CD, we can infer that CD not only dehydrates but also undergoes a conformational change upon binding to the channel. As a practical outcome, our results also demonstrate how osmotic stress can improve single-molecule detection of different solutes using protein-based nanopores.

  17. Synthesis and characterization of an amphiphilic cyclodextrin, a micelle with two recognition sites. (United States)

    Silva, O Fernando; Fernández, Mariana A; Pennie, Sarah L; Gil, Roberto R; de Rossi, Rita H


    A cyclodextrin derivative (Mod-CD) was synthesized through the monoesterification of beta-cyclodextrin (beta-CD) with 3-((E)-dec-2-enyl)-dihydrofuran-2,5-dione. The compound is an interesting surfactant that can form large aggregates not only through the interaction of the hydrophobic tails as in common amphiphilic compounds but also through the inclusion of the alkenyl chain into the cavity of another Mod-CD molecule. The self-inclusion of the chain in the cavity of cyclodextrin as well as the intermolecular inclusion was demonstrated by 1H NMR measurements that were able to detect methyl groups in three different environments. Besides, in the aggregates of Mod-CD, the cavity is available to interact with external guests such as phenolphthalein, 1-amino adamantane, and Prodan. Phenolphthalein has the same binding constant with Mod-CD and beta-CD, but the equilibrium constant for the interaction with Prodan is about 2 times larger for Mod-CD than for beta-CD. The latter result is attributed to the fact that this probe interacts with the micelle in two binding sites: the cavity of the cyclodextrin and the apolar heart of the micelle as evidenced by the spectrofluorimetric behavior of Prodan in solutions containing different concentrations of Mod-CD.

  18. A Robust Open Framework Formed by Decavanadate Clusters and Copper(II) Complexes of Macrocyclic Polyamines: Permanent Microporosity and Catalytic Oxidation of Cycloalkanes. (United States)

    Martín-Caballero, Jagoba; San José Wéry, Ana; Reinoso, Santiago; Artetxe, Beñat; San Felices, Leire; El Bakkali, Bouchra; Trautwein, Guido; Alcañiz-Monge, Juan; Vilas, José Luis; Gutiérrez-Zorrilla, Juan M


    The first decavanadate-based microporous hybrid, namely, [Cu(cyclam)][{Cu(cyclam)}2(V10O28)]·10H2O (1, cyclam = 1,4,8,11-tetraazacyclotetradecane) was prepared by reaction of (VO3)(-) anions and {Cu(cyclam)}(2+) complexes in NaCl (aq) at pH 4.6-4.7 and characterized by elemental analyses, thermogravimetry, and X-ray diffraction (powder, single-crystal) techniques. Compound 1 exhibits a POMOF-like supramolecular open-framework built of covalent decavanadate/metalorganic layers with square-like voids, the stacking of which is aided by interlamellar cementing complexes and generates water-filled channels with approximate cross sections of 10.4 × 8.8 Å(2). The framework is robust enough to remain virtually unaltered upon thermal evacuation of all water molecules of hydration, as demonstrated through single-crystal X-ray diffraction studies on the anhydrous phase 1a. This permanent microporosity renders interesting functionality to 1, such as selective adsorption of CO2 over N2 and remarkable activity as heterogeneous catalyst toward the H2O2-based oxidation of the highly-stable, tricyclic alkane adamantane.

  19. Synthesis and Antimicrobial Activity of N′-Heteroarylidene-1-adamantylcarbohydrazides and (±-2-(1-Adamantyl-4-acetyl-5-[5-(4-substituted phenyl-3-isoxazolyl]-1,3,4-oxadiazolines

    Directory of Open Access Journals (Sweden)

    Abdul-Malek S. Al-Tamimi


    Full Text Available The reaction of adamantane-1-carbohydrazide (1 with heterocyclic aldehydes, namely 5-(4-chlorophenylisoxazole-3-carboxaldehyde (2a, 5-(4-methylphenylisoxazole-3-carboxaldehyde (2b, 5-(4-methoxyphenylisoxazole-3-carboxaldehyde (2c, 1H-imidazole-2-carboxaldehyde and 2-butyl-4-chloro-1H-imidazole-5-carboxaldehyde, in ethanol, yielded the corresponding N′-heteroarylidene-1-adamantylcarbohydrazides 3a, 3b, 3c, 4 and 5, respectively, in good yields. The 4-acetyl-1,3,4-oxadiazoline analogues 6a‑c were prepared in 48–55% yields by heating their corresponding N′-heteroarylidene-1-adamantylcarbohydrazides 3a–c with acetic anhydride for two hours. Compounds 3a–c, 4, 5 and 6a–c were tested for in vitro activities against a panel of Gram-positive and Gram-negative bacteria and the yeast-like pathogenic fungus Candida albicans. Compounds 4 and 5 displayed potent broad-spectrum antimicrobial activity, while compounds 3a–c showed good activity against the Gram-positive bacteria.

  20. Conformational analysis of the EPR spectra of cyclohexenyl radical and some of its alkyl derivatives

    International Nuclear Information System (INIS)

    de Tannoux, N.M.


    Electron paramagnetic resonance spectra have been obtained for radicals produced by x-irradiation of cyclohexene and various alkyl-substituted cyclohexenes trapped in an adamantane matrix. Temperature variations of these spectra permits determination of the enthalpy and entropy of activation for interconversion between the conformations. For cyclohexenyl radical, the enthalpy of activation is 6.81 +- 0.58 kcal/mole and the entropy of activation is -0.04 +- 2.38 e.u. Methyl substitution on C 1 gives a radical with activation parameters similar to the parent radical. Methyl groups attached to C 5 increase the activation parameters significantly. On the basis of these observations, it is suggested the cyclohexenyl radicals exist in two conformations of the same energy which are of the ''envelope'' type, with C 1 , C 2 , C 3 , C 4 , and C 6 coplanar. A model involving a planar transition state for the interconversion process is proposed which accounts for most of the experimental results

  1. Through-Space Paramagnetic NMR Effects in Host-Guest Complexes: Potential Ruthenium(III) Metallodrugs with Macrocyclic Carriers. (United States)

    Chyba, Jan; Novák, Martin; Munzarová, Petra; Novotný, Jan; Marek, Radek


    The potential of paramagnetic ruthenium(III) compounds for use as anticancer metallodrugs has been investigated extensively during the past several decades. However, the means by which these ruthenium compounds are transported and distributed in living bodies remain relatively unexplored. In this work, we prepared several novel ruthenium(III) compounds with the general structure Na + [ trans-Ru III Cl 4 (DMSO)(L)] - (DMSO = dimethyl sulfoxide), where L stands for pyridine or imidazole linked with adamantane, a hydrophobic chemophore. The supramolecular interactions of these compounds with macrocyclic carriers of the cyclodextrin (CD) and cucurbit[ n]uril (CB) families were investigated by NMR spectroscopy, X-ray diffraction analysis, isothermal titration calorimetry, and relativistic DFT methods. The long-range hyperfine NMR effects of the paramagnetic guest on the host macrocycle are related to the distance between them and their relative orientation in the host-guest complex. The CD and CB macrocyclic carriers being studied in this account can be attached to a vector that attracts the drug-carrier system to a specific biological target and our investigation thus introduces a new possibility in the field of targeted delivery of anticancer metallodrugs based on ruthenium(III) compounds.

  2. Nickel(II) complexes of pentadentate N5 ligands as catalysts for alkane hydroxylation by using m-CPBA as oxidant: a combined experimental and computational study. (United States)

    Sankaralingam, Muniyandi; Balamurugan, Mani; Palaniandavar, Mallayan; Vadivelu, Prabha; Suresh, Cherumuttathu H


    energy to the high-spin state. The lower catalytic activity of complex 5 is mainly due to the formation of thermodynamically less accessible m-CPBA-coordinated precursor of [Ni(II) (L5)(OOCOC(6)H(4)Cl)](+) (5 a). Adamantane is oxidized to 1-adamantanol, 2-adamantanol, and 2-adamantanone (3°/2°, 10.6-11.5), and cumene is selectively oxidized to 2-phenyl-2-propanol. The incorporation of sterically hindering pyridylmethyl and quinolylmethyl donor ligands around the Ni(II) leads to a high 3°/2° bond selectivity for adamantane oxidation, which is in contrast to the lower cyclohexane oxidation activities of the complexes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Interaction of blood coagulation factor Va with phospholipid vesicles examined by using lipophilic photoreagents

    International Nuclear Information System (INIS)

    Krieg, U.C.; Isaacs, B.S.; Yemul, S.S.; Esmon, C.T.; Bayley, H.; Johnson, A.E.


    Two different lipophilic photoreagents, [ 3 H]adamantane diazirine and 3-(trifluoromethyl)-3-(m-[ 125 I]iodophenyl)diazirine (TID), have been utilized to examine the interactions of blood coagulation factor Va with calcium, prothrombin, factor Xa, and, in particular, phospholipid vesicles. With each of these structurally dissimilar reagents, the extent of photolabeling of factor Va was greater when the protein was bound to a membrane surface than when it was free in solution. Specifically, the covalent photoreaction with Vl, the smaller subunit of factor Va, was 2-fold higher in the presence of phosphatidylcholine/phosphatidylserine (PC/PS, 3:1) vesicles, to which factor Va binds, than in the presence of 100% PC vesicles, to which the protein does not bind. However, the magnitude of the PC/PS-dependent photolabeling was much less than has been observed previously with integral membrane proteins. It therefore appears that the binding of factor Va to the membrane surface exposes Vl to the lipid core of the bilayer, but that only a small portion of the Vl polypeptide is exposed to, or embedded in, the bilayer core. Addition of either prothrombin or active-site-blocked factor Xa to PC/PS-bound factor Va had little effect on the photolabeling of Vl with TID, but reduced substantially the covalent labeling of Vh, the larger subunit of factor Va. This indicates that prothrombin and factor Xa each cover nonpolar surfaces on Vh when the macromolecules associate on the PC/PS surface. It therefore seems likely that the formation of the prothrombinase complex involves a direct interaction between Vh and factor Xa and between Vh and prothrombin.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Diamondoid diacids ('O4' species) in oil sands process-affected water. (United States)

    Lengger, Sabine K; Scarlett, Alan G; West, Charles E; Rowland, Steven J


    As a by-product of oil sands extraction, large volumes of oil sands process water (OSPW) are generated, which are contaminated with a large range of water-soluble organic compounds. The acids are thought to be derived from hydrocarbons via natural biodegradation pathways such as α- and β-oxidation of alkyl substituents, which could produce mono- and diacids, for example. However, while several monoacids ('O2' species) have been identified, the presence of diacids (i.e. 'O4' species) has only been deduced from results obtained via Fourier transform infrared (FTIR) spectroscopy, Fourier transform ion cyclotron resonance high-resolution mass spectrometry (FTICR-HRMS) and nuclear magnetic resonance ((1)H-NMR) spectroscopy and the structures have never been confirmed. An extract of an OSPW from a Canadian tailings pond was analysed and the retention times and the electron ionization mass spectra of some analytes were compared with those of bis-methyl esters of authentic diacids by gas chromatography × gas chromatography/time-of-flight mass spectrometry (GCxGC/TOFMS) in nominal and accurate mass configurations. Two diamondoid diacids (3-carboxymethyladamantane-1-carboxylic acid and adamantane-1,3-dicarboxylic acid) were firmly identified as their bis-methyl esters by retention time and mass spectral matching and several other structural isomers were more tentatively assigned. Diacids have substantially increased polarity over the hydrocarbon and monoacid species from which they probably derive: as late members of biodegradation processes they may be useful indicators of weathering and ageing, not only of OSPW, but potentially of crude oil residues more generally. Structures of O4 species in OSPW have been identified. This confirms pathways of microbial biodegradation, which were only postulated previously, and may be a further indication that remediation of OSPW toxicity can occur by natural microbial action. The presence and abundance of these diacids might

  5. Injectable, NIR/pH-Responsive Nanocomposite Hydrogel as Long-Acting Implant for Chemophotothermal Synergistic Cancer Therapy. (United States)

    Xu, Xiaoyu; Huang, Ziyuan; Huang, Zeqian; Zhang, Xuefei; He, Siyu; Sun, Xiaoqi; Shen, Yifeng; Yan, Mina; Zhao, Chunshun


    In this study, gold nanorods (GNRs) were incorporated into the hydrogel networks formed by the copolymerization of N-isopropylacrylamide (NIPAm) and methacrylated poly-β-cyclodextrin (MPCD)-based macromer to fabricate an injectable and near-infrared (NIR)/pH-responsive poly(NIPAm-co-MPCD)/GNRs nanocomposite hydrogel, which could serve as a long-acting implant for chemophotothermal synergistic cancer therapy. The nanocomposite hydrogel showed superior mechanical and swelling properties, gelation characteristics, and excellent NIR-responsive property. A hydrophobic acid-labile adamantane-modified doxorubicin (AD-DOX) prodrug was loaded into the hydrogel efficiently by host-guest interaction. The nanocomposite hydrogel exhibited a manner of sustained drug release and could sustain the slow and steady release of DOX for more than 1 month. The pH-responsive release of DOX from the nanocomposite hydrogel was observed owing to the cleavage of acid-labile hydrazone bond between DOX and the adamantyl group in acidic environment. NIR irradiation could accelerate the release of DOX from the networks, which was controlled by the collapse of the hydrogel networks induced by photothermal effect of GNRs. The in vitro cytotoxicity test demonstrated the excellent biocompatibility and photothermal effect of the nanocomposite hydrogel. Moreover, the in situ-forming hydrogel showed promising tissue biocompatibility in the mouse model study. The in vivo antitumor test demonstrated the capacity of the nanocomposite hydrogel for chemophotothermal synergistic therapy with reduced adverse effects owing to the prolonged drug retention in the tumor region and efficient photothermal effect. Therefore, this injectable and NIR/pH-responsive nanocomposite hydrogel exhibited great potential as a long term drug delivery platform for chemophotothermal synergistic cancer therapy.

  6. Microfabricated inserts for magic angle coil spinning (MACS wireless NMR spectroscopy.

    Directory of Open Access Journals (Sweden)

    Vlad Badilita

    Full Text Available This article describes the development and testing of the first automatically microfabricated probes to be used in conjunction with the magic angle coil spinning (MACS NMR technique. NMR spectroscopy is a versatile technique for a large range of applications, but its intrinsically low sensitivity poses significant difficulties in analyzing mass- and volume-limited samples. The combination of microfabrication technology and MACS addresses several well-known NMR issues in a concerted manner for the first time: (i reproducible wafer-scale fabrication of the first-in-kind on-chip LC microresonator for inductive coupling of the NMR signal and reliable exploitation of MACS capabilities; (ii improving the sensitivity and the spectral resolution by simultaneous spinning the detection microcoil together with the sample at the "magic angle" of 54.74° with respect to the direction of the magnetic field (magic angle spinning - MAS, accompanied by the wireless signal transmission between the microcoil and the primary circuit of the NMR spectrometer; (iii given the high spinning rates (tens of kHz involved in the MAS methodology, the microfabricated inserts exhibit a clear kinematic advantage over their previously demonstrated counterparts due to the inherent capability to produce small radius cylindrical geometries, thus tremendously reducing the mechanical stress and tearing forces on the sample. In order to demonstrate the versatility of the microfabrication technology, we have designed MACS probes for various Larmor frequencies (194, 500 and 700 MHz testing several samples such as water, Drosophila pupae, adamantane solid and LiCl at different magic angle spinning speeds.

  7. Practical aspects of Lee Goldburg based CRAMPS techniques for high-resolution 1H NMR spectroscopy in solids: Implementation and applications (United States)

    Coelho, Cristina; Rocha, João; Madhu, P. K.; Mafra, Luís


    Elucidating the local environment of the hydrogen atoms is an important problem in materials science. Because 1H spectra in solid-state nuclear magnetic resonance (NMR) suffer from low resolution due to homogeneous broadening, even under magic-angle spinning (MAS), information of chemical interest may only be obtained using certain high-resolution 1H MAS techniques. 1H Lee-Goldburg (LG) CRAMPS (Combined Rotation And Multiple-Pulse Spectroscopy) methods are particularly well suited for studying inorganic-organic hybrid materials, rich in 1H nuclei. However, setting up CRAMPS experiments is time-consuming and not entirely trivial, facts that have discouraged their widespread use by materials scientists. To change this status quo, here we describe and discuss some important aspects of the experimental implementation of CRAMPS techniques based on LG decoupling schemes, such as FSLG (Frequency Switched), and windowed and windowless PMLG (Phase Modulated). In particular, we discuss the influence on the quality of the 1H NMR spectra of the different parameters at play, for example LG (Lee-Goldburg) pulses, radio-frequency ( rf) phase, frequency switching, and pulse imperfections, using glycine and adamantane as model compounds. The efficiency and robustness of the different LG-decoupling schemes is then illustrated on the following materials: organo-phosphorus ligand, N-(phosphonomethyl)iminodiacetic acid [H 4pmida] [I], and inorganic-organic hybrid materials (C 4H 12N 2)[Ge 2(pmida) 2OH 2]·4H 2O [II] and (C 2H 5NH 3)[Ti(H 1.5PO 4)(PO 4)] 2·H 2O [III].

  8. CG/MS quantitation of diamondoid compounds in crude oils and petroleum products

    International Nuclear Information System (INIS)

    Yang, C.; Wang, Z.D.; Hollebone, B.P.; Fingas, M.; Peng, X.; Landriault, M.


    Diamondoids are a class of saturated hydrocarbons that consist of 3-dimensionally fused cyclohexane rings. Diamondoid compounds in petroleum are the result of carbonium ion rearrangements of cyclic precursors on clay superacids in the source rock during oil generation. They are considered to be a problem due to their deposition during production of reservoir fluids and transportation of natural gas, gas condensates and light crude oils. At high concentrations, and with changes in pressure and temperature, diamondoid compounds can segregate out of reservoir fluids during production. Environmental scientists have considered fingerprinting the diamondoid hydrocarbons as a forensic method for oil spill studies. Since diamondoid compounds are thermodynamically stable, they have potential applications in oil-source correlation and differentiation for cases where traditional biomarker terpanes and steranes are absent because of environmental weathering or refining of petroleum products. Although there is increased awareness of possible use of diamondoid compounds for source identification, there is no systematic approach for using these compounds. Quantitative surveys of the abundances of diamondoids are not available. Therefore, this study developed a reliable analytical method for quantitative diamondoid analysis. Gas chromatography/mass spectrometry (GC/MS) was used to quantitatively determine diamondoid compounds (adamantane, diamantane and their alkylated homologues) in 14 fresh crude oils and 23 refined petroleum products, including light and mid-range distillate fuels, residual fuels and lubricating oils collected from different sources. Results were compared with 2 types of biomarker compounds in oil saturated hydrocarbon fractions. Several diagnostic ratios of diamondoids were developed based on their concentrations. Their potential use for forensic oil spill source identification was evaluated. 24 refs., 8 tabs., 4 figs

  9. Enhancement of tumour-specific immune responses in vivo by 'MHC loading-enhancer' (MLE.

    Directory of Open Access Journals (Sweden)

    Katharina Dickhaut

    Full Text Available BACKGROUND: Class II MHC molecules (MHC II are cell surface receptors displaying short protein fragments for the surveillance by CD4+ T cells. Antigens therefore have to be loaded onto this receptor in order to induce productive immune responses. On the cell surface, most MHC II molecules are either occupied by ligands or their binding cleft has been blocked by the acquisition of a non-receptive state. Direct loading with antigens, as required during peptide vaccinations, is therefore hindered. PRINCIPAL FINDINGS: Here we show, that the in vivo response of CD4+ T cells can be improved, when the antigens are administered together with 'MHC-loading enhancer' (MLE. MLE are small catalytic compounds able to open up the MHC binding site by triggering ligand-release and stabilizing the receptive state. Their enhancing effect on the immune response was demonstrated here with an antigen from the influenza virus and tumour associated antigens (TAA derived from the NY-ESO-1 protein. The application of these antigens in combination with adamantane ethanol (AdEtOH, an MLE compound active on human HLA-DR molecules, significantly increased the frequency of antigen-specific CD4+ T cells in mice transgenic for the human MHC II molecule. Notably, the effect was evident only with the MLE-susceptible HLA-DR molecule and not with murine MHC II molecules non-susceptible for the catalytic effect of the MLE. CONCLUSION: MLE can specifically increase the potency of a vaccine by facilitating the efficient transfer of the antigen onto the MHC molecule. They may therefore open a new way to improve vaccination efficacy and tumour-immunotherapy.

  10. Tunable biomimetic chalcogels with Fe4S4 cores and [Sn(n)S(2n+2)](4-)(n = 1, 2, 4) building blocks for solar fuel catalysis. (United States)

    Shim, Yurina; Yuhas, Benjamin D; Dyar, Scott M; Smeigh, Amanda L; Douvalis, Alexios P; Wasielewski, Michael R; Kanatzidis, Mercouri G


    Biology sustains itself by converting solar energy in a series of reactions between light harvesting components, electron transfer pathways, and redox-active centers. As an artificial system mimicking such solar energy conversion, porous chalcogenide aerogels (chalcogels) encompass the above components into a common architecture. We present here the ability to tune the redox properties of chalcogel frameworks containing biological Fe(4)S(4) clusters. We have investigated the effects of [Sn(n)S(2n+2)](4-) linking blocks ([SnS(4)](4-), [Sn(2)S(6)](4-), [Sn(4)S(10)](4-)) on the electrochemical and electrocatalytic properties of the chalcogels, as well as on the photophysical properties of incorporated light-harvesting dyes, tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)(3)(2+)). The various thiostannate linking blocks do not alter significantly the chalcogel surface area (90-310 m(2)/g) or the local environment around the Fe(4)S(4) clusters as indicated by (57)Fe Mössbauer spectroscopy. However, the varying charge density of the linking blocks greatly affects the reduction potential of the Fe(4)S(4) cluster and the electronic interaction between the clusters. We find that when the Fe(4)S(4) clusters are bridged with the adamantane [Sn(4)S(10)](4-) linking blocks, the electrochemical reduction of CS(2) and the photochemical production of hydrogen are enhanced. The ability to tune the redox properties of biomimetic chalcogels presents a novel avenue to control the function of multifunctional chalcogels for a wide range of electrochemical or photochemical processes relevant to solar fuels.

  11. Electric discharge microplasmas generated in highly fluctuating fluids: Characteristics and application to the synthesis of molecular diamond (United States)

    Stauss, Sven


    Plasma-based fabrication of novel nanomaterials and nanostructures is paramount for the development of next-generation electronic devices and for green energy applications. In particular, controlling the interactions between plasmas and materials interfaces, and the plasma fluctuations are crucial for further development of plasma-based processes and bottom-up growth of nanomaterials. Discharge microplasmas generated in supercritical fluids represent a special class of high-pressure plasmas, where fluctuations on the molecular scale influence the discharge properties and the possible bottom-up growth of nanomaterials. In the first part of the talk, we will discuss an anomaly observed for microplasmas generated near the critical point, a local decrease in the breakdown voltage, which has been observed for both molecular and monoatomic gases. This anomalous behavior is suggested to be caused by the concomitant decrease of the ionization potential due to the formation of clusters near the critical point, and the formation of extended electron mean free paths induced by the high-density fluctuation near the critical point. We will also show that when generating microplasma discharges close to the critical point, that the high-density fluctuation of the supercritical fluid persists. In the second part of the presentation, we will first introduce the basic properties of diamondoids and their potential for application in many different fields - biotechnology, medicine, opto- and nanoelectronics - before discussing their synthesis by microplasmas generated inside both conventional batch-type and continuous flow reactors, using the smallest diamondoid, adamantane, as a precursor and seed. Finally we show that one possible growth mechanism of larger diamondoids from smaller ones consists in the repeated abstraction of hydrogen terminations and the addition of methyl radicals. Supported financially in part by Grant No. 23760688 and Grant No. 21110002 from the Ministry of

  12. Soluble epoxide hydrolase inhibition improves coronary endothelial function and prevents the development of cardiac alterations in obese insulin-resistant mice. (United States)

    Roche, Clothilde; Besnier, Marie; Cassel, Roméo; Harouki, Najah; Coquerel, David; Guerrot, Dominique; Nicol, Lionel; Loizon, Emmanuelle; Remy-Jouet, Isabelle; Morisseau, Christophe; Mulder, Paul; Ouvrard-Pascaud, Antoine; Madec, Anne-Marie; Richard, Vincent; Bellien, Jeremy


    This study addressed the hypothesis that inhibiting the soluble epoxide hydrolase (sEH)-mediated degradation of epoxy-fatty acids, notably epoxyeicosatrienoic acids, has an additional impact against cardiovascular damage in insulin resistance, beyond its previously demonstrated beneficial effect on glucose homeostasis. The cardiovascular and metabolic effects of the sEH inhibitor trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid (t-AUCB; 10 mg/l in drinking water) were compared with those of the sulfonylurea glibenclamide (80 mg/l), both administered for 8 wk in FVB mice subjected to a high-fat diet (HFD; 60% fat) for 16 wk. Mice on control chow diet (10% fat) and nontreated HFD mice served as controls. Glibenclamide and t-AUCB similarly prevented the increased fasting glycemia in HFD mice, but only t-AUCB improved glucose tolerance and decreased gluconeogenesis, without modifying weight gain. Moreover, t-AUCB reduced adipose tissue inflammation, plasma free fatty acids, and LDL cholesterol and prevented hepatic steatosis. Furthermore, only the sEH inhibitor improved endothelium-dependent relaxations to acetylcholine, assessed by myography in isolated coronary arteries. This improvement was related to a restoration of epoxyeicosatrienoic acid and nitric oxide pathways, as shown by the increased inhibitory effects of the nitric oxide synthase and cytochrome P-450 epoxygenase inhibitors l-NA and MSPPOH on these relaxations. Moreover, t-AUCB decreased cardiac hypertrophy, fibrosis, and inflammation and improved diastolic function, as demonstrated by the increased E/A ratio (echocardiography) and decreased slope of the end-diastolic pressure-volume relation (invasive hemodynamics). These results demonstrate that sEH inhibition improves coronary endothelial function and prevents cardiac remodeling and diastolic dysfunction in obese insulin-resistant mice. Copyright © 2015 the American Physiological Society.

  13. Selective C-H Bond Oxidation Catalyzed by the Fe-bTAML Complex: Mechanistic Implications. (United States)

    Ghosh, Munmun; Pattanayak, Santanu; Dhar, Basab B; Singh, Kundan K; Panda, Chakadola; Sen Gupta, Sayam


    Nonheme iron complexes bearing tetradentate N-atom-donor ligands with cis labile sites show great promise for chemoselective aliphatic C-H hydroxylation. However, several challenges still limit their widespread application. We report a mechanism-guided development of a peroxidase mimicking iron complex based on the bTAML macrocyclic ligand framework (Fe-bTAML: biuret-modified tetraamido macrocyclic ligand) as a catalyst to perform selective oxidation of unactivated 3° bonds with unprecedented regioselectivity (3°:2° of 110:1 for adamantane oxidation), high stereoretention (99%), and turnover numbers (TONs) up to 300 using mCPBA as the oxidant. Ligand decomposition pathways involving acid-induced demetalation were identified, and this led to the development of more robust and efficient Fe-bTAML complexes that catalyzed chemoselective C-H oxidation. Mechanistic studies, which include correlation of the product formed with the Fe V (O) reactive intermediates generated during the reaction, indicate that the major pathway involves the cleavage of C-H bonds by Fe V (O). When these oxidations were performed in the presence of air, the yield of the oxidized product doubled, but the stereoretention remained unchanged. On the basis of 18 O labeling and other mechanistic studies, we propose a mechanism that involves the dual activation of mCPBA and O 2 by Fe-bTAML, leading to formation of the Fe V (O) intermediate. This high-valent iron oxo remains the active intermediate for most of the reaction, resulting in high regio- and stereoselectivity during product formation.

  14. Molecular epidemiology of influenza A/H3N2 viruses circulating in Uganda.

    Directory of Open Access Journals (Sweden)

    Denis K Byarugaba

    Full Text Available The increasing availability of complete influenza virus genomes is deepening our understanding of influenza evolutionary dynamics and facilitating the selection of vaccine strains. However, only one complete African influenza virus sequence is available in the public domain. Here we present a complete genome analysis of 59 influenza A/H3N2 viruses isolated from humans in Uganda during the 2008 and 2009 season. Isolates were recovered from hospital-based sentinel surveillance for influenza-like illnesses and their whole genome sequenced. The viruses circulating during these two seasons clearly differed from each other phylogenetically. They showed a slow evolution away from the 2009/10 recommended vaccine strain (A/Brisbane/10/07, instead clustering with the 2010/11 recommended vaccine strain (A/Perth/16/09 in the A/Victoria/208/09 clade, as observed in other global regions. All of the isolates carried the adamantane resistance marker S31N in the M2 gene and carried several markers of enhanced transmission; as expected, none carried any marker of neuraminidase inhibitor resistance. The hemagglutinin gene of the 2009 isolates differed from that of the 2008 isolates in antigenic sites A, B, D, and to a lesser extent, C and E indicating evidence of an early phylogenetic shift from the 2008 to 2009 viruses. The internal genes of the 2009 isolates were similar to those of one 2008 isolate, A/Uganda/MUWRP-050/2008. Another 2008 isolate had a truncated PB1-F2 protein. Whole genome sequencing can enhance surveillance of future seasonal changes in the viral genome which is crucial to ensure that selected vaccine strains are protective against the strains circulating in Eastern Africa. This data provides an important baseline for this surveillance. Overall the influenza virus activity in Uganda appears to mirror that observed in other regions of the southern hemisphere.

  15. Detailed NMR investigation of cyclodextrin-perfluorinated surfactant interactions in aqueous media

    Energy Technology Data Exchange (ETDEWEB)

    Weiss-Errico, Mary Jo; O’Shea, Kevin E., E-mail:


    Highlights: • Perfluorochemicals (PFCs) are strongly encapsulated by cyclodextrins (CDs). • Competition studies confirm strong CD:PFC host-guest interactions. • {sup 19}F NMR Spectroscopy demonstrates association constants up to 10{sup 5} M{sup −1}. • Position of CD along PFC chain is elucidated from NMR results. • CD:PFC complex is not disturbed under a variety of water quality conditions. - Abstract: Perfluorochemicals (PFCs) are contaminants of serious concern because of their toxicological properties, widespread presence in drinking water sources, and incredible stability in the environment. To assess the potential application of α-, β-, and γ-cyclodextrins for PFC remediation, we investigated their complexation with linear fluorinated carboxylic acids, sulfonates, and a sulfonamide with carbon backbones ranging from C4-C9. {sup 19}F Nuclear Magnetic Resonance (NMR) spectroscopy studies demonstrated β-CD formed the strongest complexes with these PFCs. The polar head group had a modest influence, but for PFCs with backbones longer than six carbons, strong association constants are observed for 1:1 (K{sub 1:1} ∼ 10{sup 5} M{sup −1}) and 2:1 (K{sub 2:1} ∼ 10{sup 3} M{sup −1}) β-CD:PFC complexes. Excess β-CD can be used to complex 99.5% of the longer chain PFCs. Competition studies with adamantane-carboxylic acid and phenol confirmed the nature and persistence of the β-CD:PFC complex. Detailed analyses of the individual NMR chemical shifts and Job plots indicate the favored positions of the β-CD along the PFC chain. Solution pH, ionic strength, and the presence of humic acid have modest influence on the β-CD:PFC complexes. The strong encapsulation of PFCs by β-CD under a variety of water quality conditions demonstrates the tremendous potential of CD-based materials for the environmental remediation of PFCs.

  16. X-ray Inducible Luminescence and Singlet Oxygen Sensitization by an Octahedral Molybdenum Cluster Compound: A New Class of Nanoscintillators. (United States)

    Kirakci, Kaplan; Kubát, Pavel; Fejfarová, Karla; Martinčík, Jiří; Nikl, Martin; Lang, Kamil


    Newly synthesized octahedral molybdenum cluster compound (n-Bu4N)2[Mo6I8(OOC-1-adamantane)6] revealed uncharted features applicable for the development of X-ray inducible luminescent materials and sensitizers of singlet oxygen, O2((1)Δg). The compound exhibits a red-NIR luminescence in the solid state and in solution (e.g., quantum yield of 0.76 in tetrahydrofuran) upon excitation by UV-vis light. The luminescence originating from the excited triplet states is quenched by molecular oxygen to produce O2((1)Δg) with a high quantum yield. Irradiation of the compound by X-rays generated a radioluminescence with the same emission spectrum as that obtained by UV-vis excitation. It proves the formation of the same excited triplet states regardless of the excitation source. By virtue of the described behavior, the compound is suggested as an efficient sensitizer of O2((1)Δg) upon X-ray excitation. The luminescence and radioluminescence properties were maintained upon embedding the compound in polystyrene films. In addition, polystyrene induced an enhancement of the radioluminescence intensity via energy transfer from the scintillating polymeric matrix. Sulfonated polystyrene nanofibers were used for the preparation of nanoparticles which form stable dispersions in water, while keeping intact the luminescence properties of the embedded compound over a long time period. Due to their small size and high oxygen diffusivity, these nanoparticles are suitable carriers of sensitizers of O2((1)Δg). The presented results define a new class of nanoscintillators with promising properties for X-ray inducible photodynamic therapy.

  17. Proteasomal degradation of sphingosine kinase 1 and inhibition of dihydroceramide desaturase by the sphingosine kinase inhibitors, SKi or ABC294640, induces growth arrest in androgen-independent LNCaP-AI prostate cancer cells. (United States)

    McNaughton, Melissa; Pitman, Melissa; Pitson, Stuart M; Pyne, Nigel J; Pyne, Susan


    Sphingosine kinases (two isoforms termed SK1 and SK2) catalyse the formation of the bioactive lipid sphingosine 1-phosphate. We demonstrate here that the SK2 inhibitor, ABC294640 (3-(4-chlorophenyl)-adamantane-1-carboxylic acid (pyridin-4-ylmethyl)amide) or the SK1/SK2 inhibitor, SKi (2-(p-hydroxyanilino)-4-(p-chlorophenyl)thiazole)) induce the proteasomal degradation of SK1a (Mr = 42 kDa) and inhibit DNA synthesis in androgen-independent LNCaP-AI prostate cancer cells. These effects are recapitulated by the dihydroceramide desaturase (Des1) inhibitor, fenretinide. Moreover, SKi or ABC294640 reduce Des1 activity in Jurkat cells and ABC294640 induces the proteasomal degradation of Des1 (Mr = 38 kDa) in LNCaP-AI prostate cancer cells. Furthermore, SKi or ABC294640 or fenretinide increase the expression of the senescence markers, p53 and p21 in LNCaP-AI prostate cancer cells. The siRNA knockdown of SK1 or SK2 failed to increase p53 and p21 expression, but the former did reduce DNA synthesis in LNCaP-AI prostate cancer cells. Moreover, N-acetylcysteine (reactive oxygen species scavenger) blocked the SK inhibitor-induced increase in p21 and p53 expression but had no effect on the proteasomal degradation of SK1a. In addition, siRNA knockdown of Des1 increased p53 expression while a combination of Des1/SK1 siRNA increased the expression of p21. Therefore, Des1 and SK1 participate in regulating LNCaP-AI prostate cancer cell growth and this involves p53/p21-dependent and -independent pathways. Therefore, we propose targeting androgen-independent prostate cancer cells with compounds that affect Des1/SK1 to modulate both de novo and sphingolipid rheostat pathways in order to induce growth arrest.

  18. Soluble epoxide hydrolase inhibition and gene deletion are protective against myocardial ischemia-reperfusion injury in vivo. (United States)

    Motoki, Atsuko; Merkel, Matthias J; Packwood, William H; Cao, Zhiping; Liu, Lijuan; Iliff, Jeffrey; Alkayed, Nabil J; Van Winkle, Donna M


    Soluble epoxide hydrolase (sEH) metabolizes epoxyeicosatrienoic acids (EETs) to dihydroxyeicosatrienoic acids. EETs are formed from arachidonic acid during myocardial ischemia and play a protective role against ischemic cell death. Deletion of sEH has been shown to be protective against myocardial ischemia in the isolated heart preparation. We tested the hypothesis that sEH inactivation by targeted gene deletion or pharmacological inhibition reduces infarct size (I) after regional myocardial ischemia-reperfusion injury in vivo. Male C57BL\\6J wild-type or sEH knockout mice were subjected to 40 min of left coronary artery (LCA) occlusion and 2 h of reperfusion. Wild-type mice were injected intraperitoneally with 12-(3-adamantan-1-yl-ureido)-dodecanoic acid butyl ester (AUDA-BE), a sEH inhibitor, 30 min before LCA occlusion or during ischemia 10 min before reperfusion. 14,15-EET, the main substrate for sEH, was administered intravenously 15 min before LCA occlusion or during ischemia 5 min before reperfusion. The EET antagonist 14,15-epoxyeicosa-5(Z)-enoic acid (EEZE) was given intravenously 15 min before reperfusion. Area at risk (AAR) and I were assessed using fluorescent microspheres and triphenyltetrazolium chloride, and I was expressed as I/AAR. I was significantly reduced in animals treated with AUDA-BE or 14,15-EET, independent of the time of administration. The cardioprotective effect of AUDA-BE was abolished by the EET antagonist 14,15-EEZE. Immunohistochemistry revealed abundant sEH protein expression in left ventricular tissue. Strategies to increase 14,15-EET, including sEH inactivation, may represent a novel therapeutic approach for cardioprotection against myocardial ischemia-reperfusion injury.

  19. Genetic Characterization of H1N1 and H1N2 Influenza A Viruses Circulating in Ontario Pigs in 2012 (United States)

    Grgić, Helena; Costa, Marcio; Friendship, Robert M.; Carman, Susy; Nagy, Éva; Poljak, Zvonimir


    The objective of this study was to characterize H1N1 and H1N2 influenza A virus isolates detected during outbreaks of respiratory disease in pig herds in Ontario (Canada) in 2012. Six influenza viruses were included in analysis using full genome sequencing based on the 454 platform. In five H1N1 isolates, all eight segments were genetically related to 2009 pandemic virus (A(H1N1)pdm09). One H1N2 isolate had hemagglutinin (HA), polymerase A (PA) and non-structural (NS) genes closely related to A(H1N1)pdm09, and neuraminidase (NA), matrix (M), polymerase B1 (PB1), polymerase B2 (PB2), and nucleoprotein (NP) genes originating from a triple-reassortant H3N2 virus (tr H3N2). The HA gene of five Ontario H1 isolates exhibited high identity of 99% with the human A(H1N1)pdm09 [A/Mexico/InDRE4487/09] from Mexico, while one Ontario H1N1 isolate had only 96.9% identity with this Mexican virus. Each of the five Ontario H1N1 viruses had between one and four amino acid (aa) changes within five antigenic sites, while one Ontario H1N2 virus had two aa changes within two antigenic sites. Such aa changes in antigenic sites could have an effect on antibody recognition and ultimately have implications for immunization practices. According to aa sequence analysis of the M2 protein, Ontario H1N1 and H1N2 viruses can be expected to offer resistance to adamantane derivatives, but not to neuraminidase inhibitors. PMID:26030614

  20. Synthesis, antimicrobial, and anti-inflammatory activity, of novel S-substituted and N-substituted 5-(1-adamantyl-1,2,4-triazole-3-thiols

    Directory of Open Access Journals (Sweden)

    Al-Abdullah ES


    Full Text Available Ebtehal S Al-Abdullah,1 Hanadi H Asiri,1 Siham Lahsasni,2 Elsayed E Habib,3 Tarek M Ibrahim,4 Ali A El-Emam1 1Department of Pharmaceutical Chemistry, College of Pharmacy, 2Department of Chemistry, College of Sciences, King Saud University, Riyadh, 3Department of Pharmaceutics and Pharmaceutical Technology, College of Pharmacy, Taibah University, Medinah, Saudi Arabia; 4Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Mansoura, Mansoura, Egypt Abstract: The reaction of 5-(1-adamantyl-4-phenyl-1,2,4-triazoline-3-thione (compound 5 with formaldehyde and 1-substituted piperazines yielded the corresponding N-Mannich bases 6a–f. The reaction of 5-(1-adamantyl-4-methyl-1,2,4-triazoline-3-thione 8 with various 2-aminoethyl chloride yielded separable mixtures of the S-(2-aminoethyl 9a–d and the N-(2-aminoethyl 10a–d derivatives. The reaction of compound 5 with 1-bromo-2-methoxyethane, various aryl methyl halides, and ethyl bromoacetate solely yielded the S-substituted products 11, 12a–d, and 13. The new compounds were tested for activity against a panel of Gram-positive and Gram-negative bacteria and the pathogenic fungus Candida albicans. Compounds 6b, 6c, 6d, 6e, 6f, 10b, 10c, 10d, 12c, 12d, 12e, 13, and 14 displayed potent antibacterial activity. Meanwhile, compounds 13 and 14 produced good dose-dependent anti-inflammatory activity against carrageenan-induced paw edema in rats. Keywords: adamantane derivatives, 1,2,4-triazoles, N-Mannich bases, antimicrobial activity, anti-inflammatory activity

  1. Experimental quantification of decoherence via the Loschmidt echo in a many spin system with scaled dipolar Hamiltonians

    Energy Technology Data Exchange (ETDEWEB)

    Buljubasich, Lisandro; Dente, Axel D.; Levstein, Patricia R.; Chattah, Ana K.; Pastawski, Horacio M. [Instituto de Física Enrique Gaviola (IFEG-CONICET), Córdoba 5000 (Argentina); Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba 5000 (Argentina); Sánchez, Claudia M. [Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba 5000 (Argentina)


    We performed Loschmidt echo nuclear magnetic resonance experiments to study decoherence under a scaled dipolar Hamiltonian by means of a symmetrical time-reversal pulse sequence denominated Proportionally Refocused Loschmidt (PRL) echo. The many-spin system represented by the protons in polycrystalline adamantane evolves through two steps of evolution characterized by the secular part of the dipolar Hamiltonian, scaled down with a factor |k| and opposite signs. The scaling factor can be varied continuously from 0 to 1/2, giving access to a range of complexity in the dynamics. The experimental results for the Loschmidt echoes showed a spreading of the decay rates that correlate directly to the scaling factors |k|, giving evidence that the decoherence is partially governed by the coherent dynamics. The average Hamiltonian theory was applied to give an insight into the spin dynamics during the pulse sequence. The calculations were performed for every single radio frequency block in contrast to the most widely used form. The first order of the average Hamiltonian numerically computed for an 8-spin system showed decay rates that progressively decrease as the secular dipolar Hamiltonian becomes weaker. Notably, the first order Hamiltonian term neglected by conventional calculations yielded an explanation for the ordering of the experimental decoherence rates. However, there is a strong overall decoherence observed in the experiments which is not reflected by the theoretical results. The fact that the non-inverted terms do not account for this effect is a challenging topic. A number of experiments to further explore the relation of the complete Hamiltonian with this dominant decoherence rate are proposed.

  2. Trace analysis of total naphthenic acids in aqueous environmental matrices by liquid chromatography/mass spectrometry-quadrupole time of flight mass spectrometry direct injection. (United States)

    Brunswick, Pamela; Shang, Dayue; van Aggelen, Graham; Hindle, Ralph; Hewitt, L Mark; Frank, Richard A; Haberl, Maxine; Kim, Marcus


    and a quantitative assay of an adamantane carboxylic acid is reported. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

  3. Tuning the conversion of cyclohexane into cyclohexanol/one by molecular dioxygen, protons and reducing agents at a single non-porphyrinic iron centre and chemical versatility of the tris(2-pyridylmethyl)amine TPAFe(II)Cl2 complex in mild oxidation chemistry. (United States)

    Jaafar, Hassen; Vileno, Bertrand; Thibon, Aurore; Mandon, Dominique


    We report that the oxygen sensitivity of some Fe(II) complexes with tripodal ligands can be used, with benefit, in the oxidation of cyclohexane under mild conditions. Depending on the solvent, two very different reaction pathways are involved, which share the coordination of O(2) to the metal as the common initial step. We have synthesized a series of α-chlorinated tripods in the tris(2-pyridylmethyl)amine series Cl(n)TPA (n = 1-3) and fully characterized the corresponding FeX(2) complexes (X = Cl, CF(3)SO(3)). The single-crystal X-ray structure analyses of the FeCl(2) complexes are reported. In CH(3)CN, the FeCl(2) complexes react smoothly with O(2), whereas the Fe(CF(3)SO(3))(2) complexes are non-sensitive. In CH(3)CN, the reaction of the oxygen-sensitive Cl(n)TPAFeCl(2) (n = 0-3) with O(2), acetic acid and zinc amalgam, in the presence of cyclohexane, affords a mixture of cyclohexanol/one in an ≈ ol/one ratio of 3.1 and a selectivity of the C3°/C2° in the adamantane conversion that is consistent with a metal-oxo based oxidation. Limited efficiency (≈ 2 TON) was observed for the parent TPAFeCl(2) complex and Cl(1)TPAFeCl(2), whereas both other complexes turned out to be poorly active. The TPAFeCl(2) complex was used to address mechanistic questions: when the reaction was carried out in pyridine, the ol/one ratio shifted to 0.15 while efficiency was improved by 7-fold. In pyridine and in the presence of a spin trap (DMPO), the radical-based character of the reaction was definitely established, by contrast with acetonitrile, where no oxygenated radicals were detected. Thus, the reactivity differences arise from involvement of two distinct active species. The dichotomous radical/biomimetic pathway is discussed to interpret these results.

  4. H5N1 surveillance in migratory birds in Java, Indonesia. (United States)

    Stoops, Arthur C; Barbara, Katie A; Indrawan, Mochamad; Ibrahim, Ima N; Petrus, Wicaksana B; Wijaya, Susan; Farzeli, Arik; Antonjaya, Ungke; Sin, Lim W; Hidayatullah, N; Kristanto, Ige; Tampubolon, A M; Purnama, S; Supriatna, Adam; Burgess, Timothy H; Williams, Maya; Putnam, Shannon D; Tobias, Steve; Blair, Patrick J


    We sought to elucidate the role of migratory birds in transmission of H5N1 in an enzoonotic area. Resident, captive, and migratory birds were sampled at five sites in Java, Indonesia. Mist nets were used to trap birds. Birds were identified to species. RNA was extracted from swabs and reverse transcriptase polymerase chain reaction (RT-PCR) conducted for the HA and M genes of H5N1. Antibodies were detected by enzyme-linked immunosorbent assay and hemagglutination inhibition test. Between October 2006 and September 2007, a total of 4,067 captive, resident, and migratory birds comprising 98 species in 23 genera were sampled. The most commonly collected birds were the common sandpiper (6% of total), striated heron (3%), and the domestic chicken (14%). The overall prevalence of H5N1 antibodies was 5.3%. A significantly higher percentage of captive birds (16.1%) showed antibody evidence of H5N1 exposure when compared to migratory or resident birds. The greatest number of seropositive birds in each category were Muschovy duck (captive), striated heron (resident), and the Pacific golden plover (migratory). Seven apparently well captive birds yielded molecular evidence of H5N1 infection. Following amplification, the HA, NA, and M genes were analyzed. Phylogenetic analysis of the HA gene showed that the isolates were 97% similar to EU124153.1 A/chicken/West Java/Garut May 2006, an isolate obtained in a similar region of West Java. While no known markers of neuraminidase inhibitor resistance were found within the NA gene, M segment analysis revealed the V27A mutation known to confer resistance to adamantanes. Our results demonstrate moderate serologic evidence of H5N1 infection in captive birds, sampled in five sites in Java, Indonesia, but only occasional infection in resident and migratory birds. These data imply that in an enzoonotic region of Indonesia the role of migratory birds in transmission of H5N1 is limited.

  5. Adsorption properties of cross-linked cellulose-epichlorohydrin polymers in aqueous solution. (United States)

    Udoetok, Inimfon A; Dimmick, Raquel M; Wilson, Lee D; Headley, John V


    Cellulose was cross-linked with epichlorohydrin (EP) at variable levels (CLE-0.5, CLE-2 and CLE-4), where CLE-i denotes the cellulose to EP mole ratios. The cross-linked products were characterized by TGA and FT-IR spectroscopy, pH at the point of zero charge (pHpzc), water swelling, and dye-adsorption methods employing two types of dyes [phenolphthalein (phth) and p-nitrophenol (PNP)]. The characterization methods provide evidence of cross-linking of cellulose in accordance with variations in surface area, PZC, available surface hydroxyl groups, and thermal stability when compared against pristine cellulose. The pHpzc of the sorbent materials was ∼ 6.5 indicating a negative surface charge occurs above pHpzc. The cross-linked polymers possess greater swelling properties relative to pristine cellulose. Detailed adsorption studies were carried out at pH 9 for cellulose and CLE-i with five types single component carboxylate anions [2-hexyldecanoic acid (S1), trans-4-pentylcyclohexanecarboxylic acid (S2), 2-dicyclohexylacetic acid (S3), adamantane carboxylic acid (S4), and cyclohexane carboxylic acid (S5)] at 295 K. The uptake properties of PNP with cellulose and CLE-i were also compared at pH 5 and 9, respectively. CLE-2 had the highest uptake of PNP (Qm=1.22 × 10(-1)mmol/g, pH 9) and S1 (Qm=4.27 mg/g) while cellulose and CLE-4 had the strongest binding affinity (1.43 L/mmol and 5.90 × 10(-2)L/mg), respectively. Uptake of PNP by CLE-0.5 at pH 5 (Q m=5.30 × 10(-2)mmol/g) was higher than uptake at pH 9 (Qm=3.11 × 10(-2)mmol/g). Sorption of CLE-4 with S1, S2 and S3 showed that relative uptake of the surrogates had the following order: S3>S2>S1, where S2 had the strongest binding affinity to CLE-i. CLE-2 had the highest sorption capacity towards Si in an equimolar mixture with evidence of molecular selective uptake. At pH 9, low uptake was mainly related to electrostatic repulsion between the negatively charged sorbent surface and the carboxylate head groups of Si

  6. Chemical and electrochemical oxidation of small organic molecules (United States)

    Smart, Marshall C.

    generated as the major products in good to excellent yields. The oxidation of other organic substrates was also investigated using urea-hydrogen peroxide as an oxidation reagent, including cyclohexylamine, 1-adamantaneamine, and adamantane.

  7. High-Resolution Infrared Spectroscopy of Cubane, C_8H_8 (United States)

    Boudon, Vincent; Pirali, Olivier; Gruet, Sébastien; D'accolti, Lucia; Fusco, Caterina; Annese, Cosimo


    Carbon-cage molecules have generated a considerable interest from both experimental and theoretical point of views. We recently performed a high-resolution study of adamantane (C10H16), the smallest hydrocarbon cage belonging to the diamandoid family. There exist another family of hydrocarbon cages with additional interesting chemical properties: the so-called Platonic hydrocarbons that comprise dodecahedrane (C20H20) and cubane (C_8H_8). Both possess C-C bond angles that deviate from the tetrahedral angle (109.8°) of the sp^3 hybridized form of carbon. This generates a considerable strain in the molecule. Cubane itself has the highest density of all hydrocarbons (1.29 g/cm^3). This makes it able to store larges amounts of energy, although the molecule is fully stable. Up to now, only one high-resolution study of cubane has been performed on a few bands [2]. We report here a new wide-range high-resolution study of the infrared spectrum of cubane. The sample was synthesized in Bari upon decarboxylation of 1,4-cubanedicarboxylic acid thanks to the improved synthesis of literature [3]; its {}1H and 13C NMR, FTIR, and mass spectrometry agreed with reported data [4]. Several spectra have been recorded at the AILES beamline of the SOLEIL French synchrotron facility. They cover the 800 to 3100 cm-1 region. Besides the three infrared-active fundamentals (ν10, ν11 and ν12), we could record many combination bands, all of them displaying a well-resolved octahedral rotational structure. We present here a preliminary analysis of some of the recorded bands, performed thanks the SPVIEW and XTDS software, based on the tensrorial formalism developed in the Dijon group [5]. [1] O. Pirali, V. Boudon, J. Oomens, M. Vervloet, J. Chem. Phys., 136, 024310 (2012). [2] A. S. Pine, A. G. Maki, A. G. Robiette, B. J. Krohn, J. K. G. Watson, Th. Urbanek, J. Am. Chem. Soc., 106, 891-897 (1984). [3] P. E. Eaton, N. Nordari, J. Tsanaktsidis, P. S. Upadhyaya, Synthesis, 1, 501, (1995). [4] E

  8. Electrochemical properties and lithium ion solvation behavior of sulfone-ester mixed electrolytes for high-voltage rechargeable lithium cells (United States)

    Watanabe, Yuu; Kinoshita, Shin-ichi; Wada, Satoshi; Hoshino, Keiji; Morimoto, Hideyuki; Tobishima, Shin-ichi


    Sulfone-ester mixed solvent electrolytes were examined for 5 V-class high-voltage rechargeable lithium cells. As the base-electrolyte, sulfolane (SL)-ethyl acetate (EA) (1:1 mixing volume ratio) containing 1 M LiBF4 solute was investigated. Electrolyte conductivity, electrochemical stability, Li+ ion solvation behavior and cycleability of lithium electrode were evaluated. 13C NMR measurement results suggest that Li+ ions are solvated with both SL and EA. Charge-discharge cycling efficiency of lithium anode in SL-EA electrolytes was poor, being due to its poor tolerance for reduction. To improve lithium charge-discharge cycling efficiency in SL-EA electrolytes, following three trials were carried out: (i) improvement of the cathodic stability of electrolyte solutions by change in polarization through modification of solvent structure; isopropyl methyl sulfone and methyl isobutyrate were investigated as alternative SL and EA, respectively, (ii) suppression of the reaction between lithium and electrolyte solutions by addition of low reactivity surfactants of cycloalkanes (decalin and adamantane) or triethylene glycol derivatives (triglyme, 1,8-bis(tert-butyldimethylsilyloxy)-3,6-dioxaoctane and triethylene glycol di(methanesulfonate)) into SL-EA electrolytes, and (iii) change in surface film by addition of surface film formation agent of vinylene carbonate (VC) into SL-EA electrolytes. These trials made lithium cycling behavior better. Lithium cycling efficiency tended to increase with a decrease in overpotential. VC addition was most effective for improvement of lithium cycling efficiency among these additives. Stable surface film is formed on lithium anode by adding VC and the resistance between anode/electrolyte interfaces showed a constant value with an increase in cycle number. When the electrolyte solutions without VC, the interfacial resistance increased with an increase in cycle number. VC addition to SL-EA was effective not only for Li/LiCoO2 cell with charge

  9. Soluble epoxide hydrolase inhibitors might prevent ischemic arrhythmias via microRNA-1 repression in primary neonatal mouse ventricular myocytes. (United States)

    Liu, Qiong; Zhao, Xuan; Peng, Ran; Wang, Mi; Zhao, Wang; Gui, Ya-Jun; Liao, Cai-Xiu; Xu, Dan-Yan


    Ischemic arrhythmias are the main causes of sudden cardiac death. It has been reported that soluble epoxide hydrolase inhibitors (sEHis) could prevent arrhythmias; however, the underlying molecular mechanisms remain unclear. In recent years, the proarrhythmic role of microRNA-1 (miR-1) has been investigated. This study aimed to elucidate whether sEHis prevented ischemic arrhythmias by suppressing miR-1. The primary neonatal mouse ventricular myocyte model of miR-1 overexpression was established by incubating with agonist microONTM mmu-miR-1a-3p agomir (DAEDstain TM Dye) (agomiR-1). The sEHi, trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid (t-AUCB), was administered following miR-1 overexpression. Quantitative real-time PCR (qPCR) and western blotting were used to test alterations in the expression of miR-1 and its target mRNAs GJA1 and KCNJ2 and their respective encoded proteins connexin 43 (Cx43) and the K + channel subunit (Kir2.1). The whole-cell patch-clamp technique was used to record the alterations of the inward rectifying K + current (I K1 ). Compared with the control group, miR-1 levels were significantly increased in the agomiR-1 group (p < 0.05), which suggested the successful construction of the miR-1 overexpression model. Compared with the control group, the levels of GJA1 and KCNJ2 mRNAs and Cx43 and Kir2.1 proteins in the agomiR-1 group were significantly decreased, and I K1 was significantly impaired (all p < 0.05). The miR-1 levels were dose-dependently decreased by t-AUCB, whereas t-AUCB dose-dependently increased the levels of GJA1 and KCNJ2 mRNAs and Cx43 and Kir2.1 proteins. Furthermore, t-AUCB restored the impaired I K1 (all p < 0.05). In conclusion, the sEHi t-AUCB has the ability to down-regulate proarrhythmic miR-1 and up-regulate its target genes and proteins, eventually restoring I K1 .

  10. Supramolecular Nanoparticles for Molecular Diagnostics and Therapeutics (United States)

    Chen, Kuan-Ju

    Over the past decades, significant efforts have been devoted to explore the use of various nanoparticle-based systems in the field of nanomedicine, including molecular imaging and therapy. Supramolecular synthetic approaches have attracted lots of attention due to their flexibility, convenience, and modularity for producing nanoparticles. In this dissertation, the developmental story of our size-controllable supramolecular nanoparticles (SNPs) will be discussed, as well as their use in specific biomedical applications. To achieve the self-assembly of SNPs, the well-characterized molecular recognition system (i.e., cyclodextrin/adamantane recognition) was employed. The resulting SNPs, which were assembled from three molecular building blocks, possess incredible stability in various physiological conditions, reversible size-controllability and dynamic disassembly that were exploited for various in vitro and in vivo applications. An advantage of using the supramolecular approach is that it enables the convenient incorporation of functional ligands onto SNP surface that confers functionality ( e.g., targeting, cell penetration) to SNPs. We utilized SNPs for molecular imaging such as magnetic resonance imaging (MRI) and positron emission tomography (PET) by introducing reporter systems (i.e., radio-isotopes, MR contrast agents, and fluorophores) into SNPs. On the other hand, the incorporation of various payloads, including drugs, genes and proteins, into SNPs showed improved delivery performance and enhanced therapeutic efficacy for these therapeutic agents. Leveraging the powers of (i) a combinatorial synthetic approach based on supramolecular assembly and (ii) a digital microreactor, a rapid developmental pathway was developed that is capable of screening SNP candidates for the ideal structural and functional properties that deliver optimal performance. Moreover, SNP-based theranostic delivery systems that combine reporter systems and therapeutic payloads into a

  11. Genomic signature-based identification of influenza A viruses using RT-PCR/electro-spray ionization mass spectrometry (ESI-MS technology.

    Directory of Open Access Journals (Sweden)

    Varough M Deyde

    Full Text Available BACKGROUND: The emergence and rapid spread of the 2009 H1N1 pandemic influenza A virus (H1N1pdm in humans highlights the importance of enhancing the capability of existing influenza surveillance systems with tools for rapid identification of emerging and re-emerging viruses. One of the new approaches is the RT-PCR electrospray ionization mass spectrometry (RT-PCR/ESI-MS technology, which is based on analysis of base composition (BC of RT-PCR amplicons from influenza "core" genes. Combination of the BC signatures represents a "genomic print" of an influenza A virus. METHODOLOGY/PRINCIPAL FINDINGS: Here, 757 samples collected between 2006 and 2009 were tested, including 302 seasonal H1N1, 171 H3N2, 7 swine triple reassortants, and 277 H1N1pdm viruses. Of the 277 H1N1pdm samples, 209 were clinical specimens (throat, nasal and nasopharyngeal swabs, nasal washes, blood and sputum. BC signatures for the clinical specimen from one of the first cases of the 2009 pandemic, A/California/04/2009, confirmed it as an unusual, previously unrecognized influenza A virus, with "core" genes related to viruses of avian, human and swine origins. Subsequent analysis of additional 276 H1N1pdm samples revealed that they shared the genomic print of A/California/04/2009, which differed from those of North American swine triple reassortant viruses, seasonal H1N1 and H3N2 and other viruses tested. Moreover, this assay allowed distinction between "core" genes of co-circulating groups of seasonal H1N1, such as clades 2B, 2C, and their reassortants with dual antiviral resistance to adamantanes and oseltamivir. CONCLUSIONS/SIGNIFICANCE: The RT-PCR/ESI-MS assay is a broad range influenza identification tool that can be used directly on clinical specimens for rapid and accurate detection of influenza virus genes. The assay differentiates the H1N1pdm from seasonal and other nonhuman hosts viruses. Although not a diagnostic tool, this assay demonstrates its usefulness and

  12. Exploring the binding nature of pyrrolidine pocket-dependent interactions in the polo-box domain of polo-like kinase 1.

    Directory of Open Access Journals (Sweden)

    Ravichandran N Murugan

    Full Text Available BACKGROUND: Over the years, a great deal of effort has been focused on the design and synthesis of potent, linear peptide inhibitors targeting the polo-like kinase 1 (Plk1, which is critically involved in multiple mitotic processes and has been established as an adverse prognostic marker for tumor patients. Plk1 localizes to its intracellular anchoring sites via its polo-box domain, and inhibiting the Plk1 polo-box domain has been considered as an approach to circumvent the specificity problems associated with inhibiting the conserved adenosine triphosphate-binding pocket. The polo-box domain consists of two different binding regions, such as the unique, broader pyrrolidine-binding pocket and the conserved, narrow, Tyr-rich hydrophobic channel, among the three Plk polo-box domains (Plks 1-3, respectively. Therefore, the studies that provide insights into the binding nature of the unique, broader pyrrolidine-binding pocket might lead to the development of selective Plk1-inhibitory compounds. METHODOLOGY/PRINCIPAL FINDINGS: In an attempt to retain the monospecificity by targeting the unique, broader pyrrolidine-binding pocket, here, for the first time, a systematic approach was undertaken to examine the structure-activity relationship of N-terminal-truncated PLHSpTM derivatives, to apply a site-directed ligand approach using bulky aromatic and non-aromatic systems, and to characterize the binding nature of these analogues using X-ray crystallographic studies. We have identified a new mode of binding interactions, having improved binding affinity and retaining the Plk1 polo-box domain specificity, at the pyrrolidine-binding pocket. Furthermore, our data revealed that the pyrrolidine-binding pocket was very specific to recognize a short and bulky hydrophobic ligand like adamantane, whereas the Tyr-rich hydrophobic channel was specific with lengthy and small hydrophobic groups. CONCLUSION/SIGNIFICANCE: The progress made using our site

  13. Antiviral drug profile of human influenza A & B viruses circulating in India: 2004-2011

    Directory of Open Access Journals (Sweden)

    V A Potdar


    Full Text Available Background & objectives: Recent influenza antiviral resistance studies in South East Asia, Europe and the United States reveal adamantane and neuraminidase inhibitor (NAIs resistance. This study was undertaken to evaluate antiviral resistance in influenza viruses isolated from various parts of India, during 2004 to 2011. Methods: Influenza viruses were analyzed genetically for known resistance markers by M2 and NA gene sequencing. Influenza A/H1N1 (n=206, A/H3N2 (n=371 viruses for amantadine resistance and A/H1N1 (n=206, A/H3N2 (n=272 and type B (n=326 for oseltamivir resistance were sequenced. Pandemic (H1N1 (n= 493 isolates were tested for H274Y mutation by real time reverse transcription (rRT-PCR. Randomly selected resistant and sensitive influenza A/H1N1 and A/H3N2 viruses were confirmed by phenotypic assay. Results: Serine to asparagine (S3IN mutation was detected in six isolates of 2007-2008.One dual-resistant A/H1N1 was detected for the first time in India with leucine to phenylalanine (L26F mutation in M2 gene and H274Y mutation in NA gene. A/H3N2 viruses showed an increase in resistance to amantadine from 22.5 per cent in 2005 to 100 per cent in 2008 onwards with S3IN mutation. Fifty of the 61 (82% A/H1N1 viruses tested in 2008-2009 were oseltamivir resistant with H274Y mutation, while all A/H3N2, pandemic A/H1N1 and type B isolates remained sensitive. Genetic results were also confirmed by phenotypic analysis of randomly selected 50 resistant A/H1N1 and 40 sensitive A/H3N2 isolates. Interpretation & conclusions: Emergence of influenza viruses resistant to amantadine and oseltamivir in spite of negligible usage of antivirals emphasizes the need for continuous monitoring of antiviral resistance.

  14. Magnetic-particle-based, ultrasensitive chemiluminescence enzyme immunoassay for free prostate-specific antigen

    International Nuclear Information System (INIS)

    Liu, Ruping; Wang, Cheng; Jiang, Quan; Zhang, Wei; Yue, Zhao; Liu, Guohua


    Graphical abstract: -- Highlights: •A low-cost and rapid assay for f-PSA in serum was developed using MMP-based CLEIA. •f-PSA detection: 0.1–30 ng mL −1 concentration range; 0.1 ng mL −1 detection limit. •The proposed method showed high sensitivity, good reproducibility and stability. •The strategy showed great potential in the fabrication of MMP-based f-PSA test kits. -- Abstract: We report a magnetic-particle (MMP)-based chemiluminescence enzyme immunoassay (CLEIA) for free prostate-specific antigen (f-PSA) in human serum. In this method, the f-PSA is sandwiched between the anti-PSA antibody coated MMPs and alkaline phosphatase (ALP)-labeled anti-f-PSA antibody. The signal produced by the emitted photons from the chemiluminescent substrate (4-methoxy-4-(3-phosphatephenyl)-spiro-(1,2-dioxetane-3,2′-adamantane)) is directly proportional to the amount of f-PSA in a sample. The present MMP-based assay can detect f-PSA in the range of 0.1–30 ng mL −1 with the detection limit of 0.1 ng mL −1 . The linear detection range could match the concentration range within the “diagnostic gray zone” of serum f-PSA levels (4–10 ng mL −1 ). The detection limit was sufficient for measuring clinically relevant f-PSA levels (>4 ng mL −1 ). Furthermore, the method was highly selective; it was unaffected by cross-reaction with human glandular kallikrein-2, a kallikrein-like serine protease that is 80% similar to f-PSA. The proposed method was finally applied to determine f-PSA in 40 samples of human sera. Results obtained using the method showed high correlation with those obtained using a commercially available microplate CLEIA kit (correlation coefficient, 0.9821). This strategy shows great potential application in the fabrication of diagnostic kits for determining f-PSA in serum

  15. Magnetic-particle-based, ultrasensitive chemiluminescence enzyme immunoassay for free prostate-specific antigen

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ruping [College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300071 (China); Wang, Cheng [College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300071 (China); Department of Mechanical Engineering, Columbia University, New York 10027 (United States); Jiang, Quan [Institute of Material Science and Engineering, Wuhan University of Technology, Wuhan 430070 (China); Zhang, Wei; Yue, Zhao [College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300071 (China); Liu, Guohua, E-mail: [College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300071 (China)


    Graphical abstract: -- Highlights: •A low-cost and rapid assay for f-PSA in serum was developed using MMP-based CLEIA. •f-PSA detection: 0.1–30 ng mL{sup −1} concentration range; 0.1 ng mL{sup −1} detection limit. •The proposed method showed high sensitivity, good reproducibility and stability. •The strategy showed great potential in the fabrication of MMP-based f-PSA test kits. -- Abstract: We report a magnetic-particle (MMP)-based chemiluminescence enzyme immunoassay (CLEIA) for free prostate-specific antigen (f-PSA) in human serum. In this method, the f-PSA is sandwiched between the anti-PSA antibody coated MMPs and alkaline phosphatase (ALP)-labeled anti-f-PSA antibody. The signal produced by the emitted photons from the chemiluminescent substrate (4-methoxy-4-(3-phosphatephenyl)-spiro-(1,2-dioxetane-3,2′-adamantane)) is directly proportional to the amount of f-PSA in a sample. The present MMP-based assay can detect f-PSA in the range of 0.1–30 ng mL{sup −1} with the detection limit of 0.1 ng mL{sup −1}. The linear detection range could match the concentration range within the “diagnostic gray zone” of serum f-PSA levels (4–10 ng mL{sup −1}). The detection limit was sufficient for measuring clinically relevant f-PSA levels (>4 ng mL{sup −1}). Furthermore, the method was highly selective; it was unaffected by cross-reaction with human glandular kallikrein-2, a kallikrein-like serine protease that is 80% similar to f-PSA. The proposed method was finally applied to determine f-PSA in 40 samples of human sera. Results obtained using the method showed high correlation with those obtained using a commercially available microplate CLEIA kit (correlation coefficient, 0.9821). This strategy shows great potential application in the fabrication of diagnostic kits for determining f-PSA in serum.

  16. Organic halide electroreduction on silver

    Energy Technology Data Exchange (ETDEWEB)

    Fiori, G.; Mussini, P.; Rondinini, S.; Vertova, A. [Milan Univ., Milan (Italy). Dept. of Physical Chemistry and Electrochemistry


    Silver, whose extraordinary electrolytically properties for organic halide reduction have been recently evidenced, has been used as cathode material for systematic preparative electrolyses in membrane-divided cells. To better elucidate the substrate role on the remarkable positive shift of reduction potentials, and on the cage effect i. e. the promotion of intermolecular reaction on adsorbed intermediates, three halide substrate patterns are here compared in terms of both voltammetric characterization and preparative electroreduction products: aliphatic halides (adamantanes), aromatic halides (phenols) and anomeric glycosyl halides. The preparative electroreductions result mainly in dimerization in the case of glycosyl halides, in H {yields} Br substitution in the case of bromophenols, in dimerization + substitution in the case of haloadamantanes. The product analysis, both at the end of the reaction and at intermediate times, allows discussing the reaction pathways in terms of intermediate stability and of active surface accessibility. The possibility of complete dehalogenation on a wider substrate variety with remarkably lower energy consumption and almost quantitative current yields makes the process potentially very interesting for environmental purposes. [Italian] L'argento, di cui sono state recentemente evidenziate straordinarie proprieta' elettrocatalitiche per la riduzione degli alogenuri organici, e' stato utilizzato come materiale catodico per sistematiche elettrolisi preparative in celle a membrana. Per mettere in risalto il ruolo del substrato organico sul notevole anticipo del potenziale di riduzione e sull'effetto gabbia, ovvero la promozione di reazioni intermolecolari su intermedi adsorbiti, vengono qui confrontate, in termini sia di caratterizzazione voltammetrica sia di prodotti di elettroriduzioni preparative, tre tipologie di alogenuri: alifatici (adamantani), aromatici (fenoli) e glicosidici. Le elettroriduzioni preparative

  17. Monitoring and Manipulating Motions of Single Molecules/Nanoparticles (United States)

    Chen, Fang

    -nanometer pores in theory. We then experimentally studied nanoparticles diffusing on membrane filters containing 200 nm polyethyleneglycol- or C18-modified pores. Using STED microscopy, we resolved for the first time how small particles are retained by the pores. Trapping by the pore entrances rather than adsorption is responsible for the retention. Further studies on C18-modified pores showed consistency in Gibbs free energy about the retention process. In addition, in order to understand how nanoparticles interact with the surface when they are forced to be on, or very close to, the surface, we studied nanosecond rotation dynamics of gold nanorods with one end attached on the surface. We found that the nanorod motion is dominated by van der Waals interaction-induced immobilization rather Brownian rotational diffusion as previously thought. The actual rotation, during which the nanorod transits from one immobilized state to the other, slows down by 50 times. The second part of the research is the collaboration with Tour's group in Rice University. The ultimate goal is to use light to drive a motorized nanocar at ambient conditions. To fulfill this goal, we first studied the moving kinetics of adamantane-wheeled nanocars on hydroxylated and PEG-modified surfaces using single molecule fluorescence microscopy. We found that nanocars' diffusion slows down on solid surface over time, which is possibly caused by the increased hydrophobicity of the substrate surface due to the adsorbates from the air. A sticky-spots model was proposed to explain the observed slowing down. To find out whether a light-activatable motor works when it is incorporated into a nanocar, we carefully designed a series of molecules containing a regular motor, a slow motor, a nonunidirectional motor, and no motor. We found that a fast unidirectional rotating motor enhanced the diffusion of the molecule in solution upon UV-illumination. Detailed analysis suggested that the unimolecular submersible nanomachine (USN

  18. NMR study of ligand exchange and electron self-exchange between oxo-centered trinuclear clusters [Fe3(μ3-O)(μ-O2CR)6(4-R'py)3](+/0). (United States)

    Novitchi, Ghenadie; Helm, Lothar; Anson, Christopher; Powell, Annie K; Merbach, André E


    The syntheses, single crystal X-ray structures, and magnetic properties of the homometallic μ₃-oxo trinuclear clusters [Fe₃(μ₃-O)(μ-O₂CCH₃)₆(4-Phpy)₃](ClO₄) (1) and [Fe₃(μ₃-O)(μ-O₂CAd)₆(4-Mepy)₃](NO₃) (2) are reported (Ad = adamantane). The persistence of the trinuclear structure within 1 and 2 in CD₂Cl₂ and C₂D₂Cl₄ solutions in the temperature range 190-390 K is demonstrated by ¹H NMR. An equilibrium between the mixed pyridine clusters [Fe₃(μ₃-O)(μ-O₂CAd)₆(4-Mepy)(3-x)(4-Phpy)(x)](NO₃) (x = 0, 1, 2, 3) with a close to statistical distribution of these species is observed in CD₂Cl₂ solutions. Variable-temperature NMR line-broadening made it possible to quantify the coordinated/free 4-Rpy exchanges at the iron centers of 1 and 2: k(ex)²⁹⁸ = 6.5 ± 1.3 × 10⁻¹ s⁻¹, ΔH(‡) = 89.47 ± 2 kJ mol⁻¹, and ΔS(‡) = +51.8 ± 6 J K⁻¹ mol⁻¹ for 1 and k(ex)²⁹⁸ = 3.4 ± 0.5 × 10⁻¹ s⁻¹, ΔH(‡) = 91.13 ± 2 kJ mol⁻¹, and ΔS(‡) = +51.9 ± 5 J K⁻¹ mol⁻¹ for 2. A limiting D mechanism is assigned for these ligand exchange reactions on the basis of first-order rate laws and positive and large entropies of activation. The exchange rates are 4 orders of magnitude slower than those observed for the ligand exchange on the reduced heterovalent cluster [Fe(III)₂Fe(II)(μ₃-O)(μ-O₂CCH₃)₆(4-Phpy)₃] (3). In 3, the intramolecular Fe(III)/Fe(II) electron exchange is too fast to be observed. At low temperatures, the 1/3 intermolecular second-order electron self-exchange reaction is faster than the 4-Phpy ligand exchange reactions on these two clusters, suggesting an outer-sphere mechanism: k₂²⁹⁸ = 72.4 ± 1.0 × 103 M⁻¹ s⁻¹, ΔH(‡) = 18.18 ± 0.3 kJ mol⁻¹, and ΔS(‡) = -90.88 ± 1.0 J K⁻¹ mol⁻¹. The [Fe₃(μ₃-O)(μ-O₂CCH₃)₆(4-Phpy)₃](+/0) electron self-exchange reaction is compared with the more than 3 orders of magnitude faster [Ru

  19. Design, synthesis, and characterization of new phosphazene related materials, and study the structure property correlations (United States)

    Tian, Zhicheng

    various gelation rates depending on the polymer structures and the concentrations. The rheological measurements of the supramolecular hydrogels indicate a fast gelation process and flowable character under a large stain. Chapter 4 outlines the preparation of a number of amphiphilic diblock copolymers based on poly[bis(trifluoroethoxy)phosphazene] (TFE) as the hydrophobic block and poly(dimethylaminoethylmethacrylate) (PDMAEMA) as the hydrophilic block. The TFE block was synthesized first by the controlled living cationic polymerization of a phosphoranimine, followed by replacement of all the chlorine atoms using sodium trifluoroethoxide. To allow for the growth of the PDMAEMA block, 3-azidopropyl-2-bromo-2-methylpropanoate, an atom transfer radical polymerization (ATRP) initiator, was grafted onto the endcap of the TFE block via the 'click' reaction followed by the ATRP of 2-(dimethylamino)ethyl methacrylate (DMAEMA). Chapter 5 is a report on the design and assembly of polyphosphazene materials based on the non-covalent "host--guest" interactions either at the terminus of the polymeric main-chains or the pendant side-chains. The supramolecular interaction at the main chain terminus was used to produce amphiphilic palm-tree like pseudo-block copolymers via host-guest interactions between an adamantane end-functionalized polyphosphazene and a 4-armed beta-cyclodextrin (beta-CD) initiated poly[poly(ethylene glycol) methyl ether methacylate] branched-star type polymer. The formation of micelles of the obtained amphiphiles was analyzed by fluorescence technique, dynamic light scattering, transmission electron microscopy, and atomic force microscopy. Chapter 6 is an investigation of the influence of bulky fluoroalkoxy side groups on the properties of polyphosphazenes. A new series of mixed-substituent high polymeric poly(fluoroalkoxyphosphazenes) containing trifluoroethoxy and branched fluoroalkoxy side groups was synthesized and characterized by NMR and GPC methods. These

  20. PREFACE: IUMRS-ICA 2008 Symposium, Sessions 'X. Applications of Synchrotron Radiation and Neutron Beam to Soft Matter Science' and 'Y. Frontier of Polymeric Nano-Soft-Materials - Precision Polymer Synthesis, Self-assembling and Their Functionalization' (United States)

    Takahara, Atsushi; Kawahara, Seiichi


    aimed to provide recent advances in polymer synthesis, self-assembling processes and morphologies, and functionalization of nano-soft-materials in order to initiate mutual and collaborative research interest that is essential to develop revolutionarily new nano-soft-materials in the decades ahead. Four Keynote lectures, 15 invited talks and 30 posters presented important new discoveries in polymeric nano-soft-materials, precision polymer synthesis, self-assembling and their functionalization. As for the precision polymer synthesis, the latest results were provided for studies on synthesis of polyrotaxane with movable graft chains, organic-inorganic hybridization of polymers, supra-molecular coordination assembly of conjugated polymers, precision polymerization of adamantane-containing monomers, production of high density polymer brush and synthesis of rod coil type polymer. The state-of-the-art results were introduced for the formation of nano-helical-structure of block copolymer containing asymmetric carbon atoms, self-assembling of block copolymers under the electric field, self-assembling of liquid crystalline elastomers, preparation of nano cylinder template films and mesoscopic simulation of phase transition of polymers and so forth. Moreover, recent advantages of three-dimensional electron microtomography and scanning force microscopy were proposed for analyses of nano-structures and properties of polymeric multi-component systems. Syntheses, properties and functions of slide-ring-gel, organic-inorganic hybrid hydrogels, hydrogel nano-particles, liquid-crystalline gels, the self-oscillating gels, and double network gels attracted participants' attention. Modifications of naturally occurring polymeric materials with supercritical carbon dioxide were introduced as a novel technology. Some of the attractive topics are presented in this issue. We are grateful to all the speakers and participants for valuable contributions and active discussions. Organizing committee

  1. Vladimir Prelog i Zavod za organsku kemiju

    Directory of Open Access Journals (Sweden)

    Jakopčić, K.


    -operation from the small but prosperous pharmaceutical company "Kaštel" in Zagreb. On behalf of the agreement, Prelog and his department obtained funds to fit up the laboratory and to start very prosperous research in the synthesis and studies of pharmaceutically interesting compounds. With his assistants, students and other collaborators, Prelog started research of cinchona bark alkaloids, preferentially oriented to the synthesis of quinine. For example, Prelog's method of double intramolecular alkylation to synthetize the quinuclidine moiety of quinine was patented by "Kaštel". With R. Seiwerth he developed the first useful synthesis of adamantane. Prelog's group started research in the field of sulphonamides and commercial success of "Streptazole" stimulated the development of the research laboratories within "Kaštel". The collaboration in the research continued in fields of other chemotherapeutics, analeptics, spasmolitics, barbiturates etc. Within the period 1935-1941, Prelog published 48 scientific papers and 8 patents. In less than seven years, his results enormously influenced the entire organic chemistry in Zagreb till nowadays. Under the confused and uncertain circumstances caused by the beginning of World War II, Prelog left Zagreb in 1941 and continued his extraordinary scientific career at the ETH in Zürich.During the war (1942-1945 the tuition and the Department were run by Dr. Rativoj Seiwerth, former collaborator and first assistant to V. Prelog. In almost unbelievable conditions, the young assistant, then assistant professor (since January 1943, R. Seiwerth fully succeeded in continuing most activities founded by Professor Prelog. After the war (1945, R. Seiwerth was forced to resign. Nevertheless, soon after R. Seiwerth continued his research work, firstly in the Institute for Industrial Research in Zagreb (1946-1952, and later in the Research Institute of "Pliva" in Zagreb. He retired in 1980.In post-war conditions (1945/46, the activity of the Technical