984 resultados para RARE EARTHS COMPLEXES
Resumo:
Cat Scratch Disease (CSD) is an infectious disorder which appears after cat scratching particularly in children and adolescents. Bartonella henselae is the etiologic agent more frequently involved. There are only a few recent reports demonstrating the disease after transplantation, although the illness is not infrequent in immunologically competent people. Indeed CSD in transplant receptors has only been recently emphasized in the literature and it was concluded that fever and lymphadenopathy in patients who had been exposed to cats should prompt clinicians to maintain a suspicion for the infection. In this report CSD infecting a renal transplanted adolescent complaining of headache, blurred vision and fever, presenting a cat scratching lesion in the right arm, with a bilateral painful cervical lymphadenopathy was related. He also presented indirect immunofluorescency identifying that the two subtype's titles of Bartonella-henselae and quintana- were elevated. Treatment with doxicicline e rifampicin was introduced and the patient became asymptomatic in about 3 weeks.
Resumo:
Herpes simplex -virus 1 (HSV-1) ja ihmisen papilloomavirus (HPV) infektoivat suun epiteelisoluja. Useimmissa tapauksissa näiden virusten infektio on kliinisesti oireeton. Suun limakalvojen oireeton HPV-infektio on aikuisilla yleinen, ja valtaosa näistä infektioista ovat ohimeneviä ja vain pieni osa johtaa krooniseen HPV-infektioon. Krooninen HPV-infektio lisää riskiä epiteelisolujen transformoitumiseen kohti syöpäsolua. HPV infektio ei ole yksinään riittävä aiheuttamaan syöpäsolun, vaan siihen tarvitaan myös muita riskitekijöitä.. Muut infektiot, kuten esimerkiksi HSV-1-infektio saattaa olla yksi näistä riskitekijöistä. Tämän syventävän opinnäytetyön tutkimuksen tavoitteena oli selvittää HSV-1-infektion esiintymistä naisten suun limakalvonäytteissä kuuden vuoden seurannassa. Toinen tavoitteemme oli selvittää HSV-1 ja HPV -yhteisinfektion esiintymistä suun epiteelisoluissa, erityisesti naisilla joilla havaittiin suun krooninen HPV-infektio. Tämä tutkimus on osa kuusivuotista seurantatutkimusta (Finnish Family HPV -tutkimus), joka suunniteltiin selvittämään HPV-infektioiden dynamiikkaa ja riskitekijöitä 329 suomalaisperheessä. Suun limakalvoilta otettiin harjausnäyte ennen synnytystä ja kuusi kertaa synnytyksen jälkeen kuuden vuoden aikana. Näytteistä eristettyä DNA:ta oli saatavilla riittävästi HSV-1-analyysiä varten yhteensä 304 naiselta (keski-ikä 25.6 vuotta). Kaikkiaan tutkittavia näytteitä oli 1,873, joista HSV-1:n esiintyminen tutkittiin käyttäen kvantitatiivista PCR:ää. Lisäksi epävarmat PCR-tulokset varmistettiin PCR-tuotteen Southern Blot hybridisaatiolla. HSV-1 tuloksia verrattiin aikaisemmin saatuihin HPV-tuloksiin. Suun limakalvonäytteistä 2.2% oli HSV-1-positiivisia ja 19.6% oli HPV-positiivisia. Yhteensä 11.8%:lla äideistä suunäyte oli HSV-1-DNA -positiivinen ainakin kerran seurannan aikana. HSV-1 ja HPV -yhteisinfektio löydettiin vain neljältä äidiltä. Suurin osa äideistä, jotka olivat HSV-1-positiivisia ennen syntymää, pysyivät HSV-1-positiivisina myös synnytyksen jälkeen. Kolmella naisella todettiin persistentti HPV-16 infektio ja kahdella heistä oli samanaikainen HSV-1 infektio. Tuloksemme osoittaa, että HSV-1:n ja HPV:n esiintyminen yhtä aikaa nuorten naisten suun limakalvolla on harvinaista. On suositeltavaa, että yhteisinfektion omaavia äitejä seurataan myös tulevaisuudessa, sillä HSV-1-infektio saattaa olla yksi riskitekijä suun limakalvon malignissa muutoksessa kroonisen HPV-infektion yhteydessä.
Resumo:
Metal-ion-mediated base-pairing of nucleic acids has attracted considerable attention during the past decade, since it offers means to expand the genetic code by artificial base-pairs, to create predesigned molecular architecture by metal-ion-mediated inter- or intra-strand cross-links, or to convert double stranded DNA to a nano-scale wire. Such applications largely depend on the presence of a modified nucleobase in both strands engaged in the duplex formation. Hybridization of metal-ion-binding oligonucleotide analogs with natural nucleic acid sequences has received much less attention in spite of obvious applications. While the natural oligonucleotides hybridize with high selectivity, their affinity for complementary sequences is inadequate for a number of applications. In the case of DNA, for example, more than 10 consecutive Watson-Crick base pairs are required for a stable duplex at room temperature, making targeting of sequences shorter than this challenging. For example, many types of cancer exhibit distinctive profiles of oncogenic miRNA, the diagnostics of which is, however, difficult owing to the presence of only short single stranded loop structures. Metallo-oligonucleotides, with their superior affinity towards their natural complements, would offer a way to overcome the low stability of short duplexes. In this study a number of metal-ion-binding surrogate nucleosides were prepared and their interaction with nucleoside 5´-monophosphates (NMPs) has been investigated by 1H NMR spectroscopy. To find metal ion complexes that could discriminate between natural nucleobases upon double helix formation, glycol nucleic acid (GNA) sequences carrying a PdII ion with vacant coordination sites at a predetermined position were synthesized and their affinity to complementary as well as mismatched counterparts quantified by UV-melting measurements.
Resumo:
En haut des pages, son des caractères difficiles des classiques ; renseignements géographiques, administratifs, etc. ; formules de prières, d'adresses, etc. En bas des pages, dictionnaire par ordre analogique d'expressions complexes avec explication. Auteur : Xu San xing Yi wu, de Hui jun.3 + 3 livres.
Resumo:
We study the phonon dispersion, cohesive and thermal properties of raxe gas solids Ne, Ar, Kr, and Xe, using a variety of potentials obtained from different approaches; such as, fitting to crystal properties, purely ab initio calculations for molecules and dimers or ab initio calculations for solid crystalline phase, a combination of ab initio calculations and fitting to either gas phase data or sohd state properties. We explore whether potentials derived with a certain approaxih have any obvious benefit over the others in reproducing the solid state properties. In particular, we study phonon dispersion, isothermal ajid adiabatic bulk moduli, thermal expansion, and elastic (shear) constants as a function of temperatiue. Anharmonic effects on thermal expansion, specific heat, and bulk moduli have been studied using A^ perturbation theory in the high temperature limit using the neaxest-neighbor central force (nncf) model as developed by Shukla and MacDonald [4]. In our study, we find that potentials based on fitting to the crystal properties have some advantage, particularly for Kr and Xe, in terms of reproducing the thermodynamic properties over an extended range of temperatiures, but agreement with the phonon frequencies with the measured values is not guaranteed. For the lighter element Ne, the LJ potential which is based on fitting to the gas phase data produces best results for the thermodynamic properties; however, the Eggenberger potential for Ne, where the potential is based on combining ab initio quantum chemical calculations and molecular dynamics simulations, produces results that have better agreement with the measured dispersion, and elastic (shear) values. For At, the Morse-type potential, which is based on M0ller-Plesset perturbation theory to fourth order (MP4) ab initio calculations, yields the best results for the thermodynamic properties, elastic (shear) constants, and the phonon dispersion curves.
Resumo:
The objective of this thesis was to demonstrate the potential of fast atom bombardment mass spectrometry (FABMS) as a probe of condensed phase systems and its possible uses for the study of hydrogen bonding. FABMS was used to study three different systems. The first study was aimed at investigating the selectivity of the ligand tris(3,6-dioxaheptyl) amine (tdoha) for the alkali metal cations. FABMS results correlated well with infrared and nmr data. Systems where a crown ether competed with tdoha for a given alkali metal cation were also investigated by fast atom bombardment. The results were found to correlate with the cation affinity of tdoha and the ability of the crown ether to bind the cation. In the second and third studies, H-bonded systems were investigated. The imidazole-electron donor complexes were investigated and FABMS results showed the expected H-bond strength of the respective complexes. The effects of concentration, liquid matrix, water content, deuterium exchange, and pre-ionization of the complex were also investigated. In the third system investigated, the abundance of the diphenyl sulfone-ammonium salt complexes (presumably H-bonded) in the FABMS spectrum were found to correlate with qualitative considerations such as steric hindrance and strength of ion pairs.
Resumo:
The Lennard-Jones Devonshire 1 (LJD) single particle theory for liquids is extended and applied to the anharmonic solid in a high temperature limit. The exact free energy for the crystal is expressed as a convergent series of terms involving larger and larger sets of contiguous particles called cell-clusters. The motions of all the particles within cell-clusters are correlated to each other and lead to non-trivial integrals of orders 3, 6, 9, ... 3N. For the first time the six dimensional integral has been calculated to high accuracy using a Lennard-Jones (6-12) pair interaction between nearest neighbours only for the f.c.c. lattice. The thermodynamic properties predicted by this model agree well with experimental results for solid Xenon.
Resumo:
We have calculated the thermodynamic properties of monatomic fcc crystals from the high temperature limit of the Helmholtz free energy. This equation of state included the static and vibrational energy components. The latter contribution was calculated to order A4 of perturbation theory, for a range of crystal volumes, in which a nearest neighbour central force model was used. We have calculated the lattice constant, the coefficient of volume expansion, the specific heat at constant volume and at constant pressure, the adiabatic and the isothermal bulk modulus, and the Gruneisen parameter, for two of the rare gas solids, Xe and Kr, and for the fcc metals Cu, Ag, Au, Al, and Pb. The LennardJones and the Morse potential were each used to represent the atomic interactions for the rare gas solids, and only the Morse potential was used for the fcc metals. The thermodynamic properties obtained from the A4 equation of state with the Lennard-Jones potential, seem to be in reasonable agreement with experiment for temperatures up to about threequarters of the melting temperature. However, for the higher temperatures, the results are less than satisfactory. For Xe and Kr, the thermodynamic properties calculated from the A2 equation of state with the Morse potential, are qualitatively similar to the A 2 results obtained with the Lennard-Jones potential, however, the properties obtained from the A4 equation of state are in good agreement with experiment, since the contribution from the A4 terms seem to be small. The lattice contribution to the thermal properties of the fcc metals was calculated from the A4 equation of state, and these results produced a slight improvement over the properties calculated from the A2 equation of state. In order to compare the calculated specific heats and bulk moduli results with experiment~ the electronic contribution to thermal properties was taken into account~ by using the free electron model. We found that the results varied significantly with the value chosen for the number of free electrons per atom.
Resumo:
A number of metal complexes containing the ligand 5,5,7,12,12,14-hexamethyl-l,4,8,11-tetra-azatetradecane were synthesized and analyzed using electron impact (EI) and fast atom bombardment (FAB). The FAB mass spectra were obtained in positive and negative ion mode. FAB in the positive ion mode proved to be the most successful technique for the identification of these compounds. In the majority of cases the spectra obtained using positive ion FAB were structurally informative, although not all showed molecular (M+) or quasimolecular ([M+H]+) ions. The fragmentations observed were characteristic of the ligands, and were interpreted based on the chemistry of these compounds.
Resumo:
In order to investigate the use of Fast Atom Bombardment Mass Spectrometry (FAB-MS) as a tool for structural characterization, two groups of complexes are analyzed. The first group is a set of ruthenium(II) coordination complexes containing bidentate polypyridyl ligands. The positive and negative ion FAB-MS spectra are found to be sufficient to allow for an almost complete characterization of the central metal atom, the ligands and the counter anions contained in the intact complex. An unusual observation of mUltiply charged ions in the positive ion FAB-MS spectra (i.e. [RUL 3 ]2+) is explained to be as a result of the oxidative quenching of the excited state of the doubly charged ion by the matrix, 3-nitrobenzyl alcohol. An analysis of a mixture shows that the technique is a good one for identifying components therein. A group of triptycene and related complexes containing Group V elements is also analyzed by FAB-MS and the results. in terms of relative abundances of fragment ions, are found to be consistent with known metal-carbon bond strengths.
Resumo:
Solid complexes of pyridoxine with Mn(II) , Cd(II) and Zn(II) have been isolated, as well as compounds containing Cu(II), Ni(II), Co(III), Cd(II) and Zn(II), and pyridoxamine in various protonated forms. Infrared spectra provide evidence for protonation at the pyridine nitrogen site in the complexes, but not in the neutral vitamins and the complexes of anionic pyridoxamine. Thus the complexed vitamins are in zwitterionic forms, with chelation probably occurring through the phenolate oxygen and either the amino or the hydroxy group at the 4' position.