ESI-MS[n] of anticancer pt[iv] organoamido complexes and their interactions with DNA-model compounds /

The general solution behaviour and" the major fragmentation pathways of the anticanceractive PtIV coordination complexes, trans, trans, cis, cis-[PtCIOH{N(pFC6F4) CH2h(pY)2] (1), trans, cis, cis-[Pt(OH)2{N(p-FC6F4)CH2h(Py)2] (2), trans, cis, cis-[Pt(OH)2{N(p-HC6F4)CH2h(Py)2] (3), trans, trans, cis, cis-[PtCIOH{N(pHC6F4) CH2h(Py)2] (4), and trans, trans, cis, cis-[PtOH(OCH3){N(p-HC6F4)CH2h(PY)2] (5) (Py = pyridine) have been deduced by positive-ion tandem-in-time ESI-MS. Overall, the acquired full-scan, positive-ion ESI-MS spectra of 2, 3, and 5 were characterized by the presence of relatively low-intensity [M+Nar and [M+Kt mass spectral peaks, whereas those of 1 and 4 were dominated by extremely intense [M+Hr peaks. Complexes 2 and 3 were also noted to form [2M+Ht and [2M+Nat dilneric cations. The source of Na + and K+ ions is believed to be the sample, the solvent systems used or the transport line carrying the sample solutions into the ES ion source. Further, the fragmentation pathway of all complexes studied was found to be almost identical with concurrent loss of py and H20 molecules, loss of a {N(p-YC6F4)CH2} (Y = F, H) group and/or concomitant release of the latter group and a py ligand being the most conunon. The photochemical degradation behaviour of 1 and 2 was also investigated using either fluorescent or ultraviolet light and some products of that degradation were positively identified. Altogether, light irradiation of solutions of both complexes resulted in cation cationisation, reductive-elimination, ligand-release, ligand-exchange and ligand-addition reactions. Finally, positive- and negative-ion ESI-MSn spectra of 5' -GMP, guanosine, inosine and products of their reactions with 1, 2,3, and 4 were also recorded. On the whole, full-scan ESI-MS spectra of the pure nucleobases revealed the presence of cationic and anionic species that are highly reflective of both their solution ionic composition and their propensity t9 form polymeric clusters. Analyses of mass spectra acquired from their reaction solutions with the aforementioned platinum complexes indicated very slow kinetics. However, all complexes investigated formed, to various degrees, Pt-nucleobase adducts with guanosine and inosine, but not with 5'-GMP. The products included species having coordination numbers of III, IV, V, and VI, among which the first-time· observed, coordinatively saturated, jive-coordinate PtlI-nucleobase complexes were of most interest. The latter complexes are presumably stabilized by 7tback- donation involving the filled d orbitals of the PtII centre and the empty pz· orbital of MeCN. All products, whose peaks appeared inlull-scan ESI-MS spectra, are believed to represent solution species rather than artifacts of gas-phase processes. Finally, negativeion ESI-MSn spectra recorded in reaction solutions of 1 and 4 with guanosine and of the latter complex with inosine revealed the negative-ion-ESI-MS first-time observed, noncovalent, nucleoside-chloride adducts, with the source of chloride anion being complexes 1 and 4 theillselves. In contrast, no such adducts were observed to form with Na25'-GMP or its protonated fonn. Few suggestions are offered for the possible cause(s) behind the absence of such adduct ions.

Gas chromatographic electron capture negative ionization mass spectrometric (GC/ECNI/MS) determination of unique fluorinated compounds in the sediments of Lake Ontario and the effect of high-boiling alcohols (as injection solvents) on chromatographic behaviour of polycyclic aromatic hydrocarbons in gas chromatography

Part I - Fluorinated Compounds A method has been developed for the extraction, concentration, and determination of two unique fluorinated compounds from the sediments of Lake Ontario. These compounds originated from a common industrial landfill, and have been carried to Lake Ontario by the Niagara River. Sediment samples from the Mississauga basin of Lake Ontario have been evaluated for these compounds and a depositional trend was established. The sediments were extracted by accelerated solvent extraction (ASE) and then underwent clean-up, fractionation, solvent exchange, and were concentrated by reduction under nitrogen gas. The concentrated extracts were analyzed by gas chromatography - electron capture negative ionization - mass spectrometry. The depositional profile determined here is reflective of the operation of the landfill and shows that these compounds are still found at concentrations well above background levels. These increased levels have been attributed to physical disturbances of previously deposited contaminated sediments, and probable continued leaching from the dumpsite. Part II - Polycyclic Aromatic Hydrocarbons Gas chromatography/mass spectrometry is the most common method for the determination of polycyclic aromatic hydrocarbons (PAHs) from various matrices. Mass discrimination of high-boiling compounds in gas chromatographic methods is well known. The use of high-boiling injection solvents shows substantial increase in the response of late-eluting peaks. These solvents have an increased efficiently in the transfer of solutes from the injector to the analytical column. The effect of I-butanol, I-pentanol, cyclopentanol, I-hexanol, toluene and n-octane, as injection solvents, was studied. Higher-boiling solvents yield increased response for all PAHs. I -Hexanol is the best solvent, in terms of P AH response, but in this solvent P AHs were more susceptible to chromatographic problems such as peak splitting and tailing. Toluene was found to be the most forgiving solvent in terms of peak symmetry and response. It offered the smallest discrepancies in response, and symmetry over a wide range of initial column temperatures.

Las propuestas metodológicas más representativas en la filosofía de la ciencia del siglo XX.

Tesis (Maestría en Ciencias) UANL

Estudio comparativo de los métodos más utilizados para la evaluación del impacto ambiental.

Tesis (Maestría en Ciencias con Especialidad en Ingeniería Ambiental) UANL

Identificación y análisis de las enfermedades más comúnes que sepresentan en los empleados de atención al público (cajeros), en algunas sucursales bancarias de Monterrey, N.L. y su relación con factores de riesgo de trabajo que ahí existen

Tesis (Maestría en Salud Pública con Especialidad en Salud en el Trabajo) UANL

Elección de las condiciones más adecuadas para la obtención de extractos de plantas superiores con actividad sobre una cepa de Staphylococcus aureus resistente

Tesis (Maestría en Ciencias con Orientación Terminal en Química Biomédica) UANL

Desarrollo y estandarización de un método para detección y cuantificación de las bacterias más frecuentes causantes de neumonía asociada a ventilador

Tesis (Maestría en Ciencias con Orientación en Microbiología Médica) U.A.N.L. Facultad de Medicina.

Análisis comparativo de los aspectos más relevantes del derecho laboral de México, Estados Unidos y Canadá por Aideé del Carmen García Arzabala

Tesis (Maestría en Derecho Laboral) U. A. N. L.

Identificar los factores de riesgo más impactantes que intervienen en la incidencia de infecciones respiratorias agudas en los niños y niñas durante su primer año de vida Héctor Martínez Alday, Haydee Lozano Gómez [e] Ileana Carolina Urdiales González.

Tesis ( Maestría en Salud Pública) U.A.N.L.

El perfil del egresado de ingeniero administrador de sistemas de la FIME-UANL para ser más competitivo por Adriana Lombardo Coronado

Tesis (Maestro en Ciencias de la Administración con Especialidad en Relaciones Industriales) U.A.N.L.

El CAADI: un instrumento más en la enseñanza del idioma inglés por Pura Rodríguez Rodríguez

Tesis (Maestro en Formación y Capacitación de Recursos Humanos) U.A.N.L.

Estudio de la temperatura de transformación Ms y microestructura en un acero inoxidable martensítico con 0.12%C mediante análisis térmico.

Tesis (Maestría en Ciencias de la Ingeniería Mecánica con Especialidad en Materiales) UANL, 2010.

Originalidad e hibridación en Amor es más laberinto. Comedia escrita por Sor Juana Inés de la Cruz y Juan de Guevara en 1689.

Tesis (Maestría en Ciencias con Especialidad en Lengua y en Literatura) UANL, 2012.

La ciudad universitaria de Nuevo León : más allá de los muros

UANL

Determinantes de la anticoncepción : el caso de las mujeres casadas o unidas que no desean más hijos

UANL