Water Below the Falls, NIagara, U.S.A.

The description of the image reads "(16) Looking at the tumbling, foaming waters, below the Falls, Niagara, U.S.A."

Rapids Above the Falls Looking at Goat Island, Niagara, U.S.A.

The description reads "(14) The rolling, tumbling "Rapids" above the Falls - along Riverside Drive, looking toward Goat Island, - Niagara, U.S.A.".

Ice and Snow, Niagara Falls, U.S.A.

The description of the image reads "514-a-A fairy-land of ice and snow, Niagara Falls, U.S.A.".

Ice Mountain Niagara Falls, U.S.A.

The description of the image reads "No. 65 - The great ice mountain and American Falls, Niagara".

Progress and Challenges in Animal Handling and Slaughter in the U.S.

The article discusses the McDonald's Corporation audit and the ways to improve the handling of livestock on the way to slaughter.

Special Orders No. 18 of the Office U.S. Army Hospital, Camp Parole

Special Orders No. 18 of the Office U.S. Army Hospital, Camp Parole, near Annapolis, MD., March 14, 1865 to W.K. Cleveland assigning him to duty as pathologist and consulting surgeon for the hospital. This is signed by W. Stewart, Surgeon U.S. Vol’s, in charge, March 14, 1865.

DFT Studies of the Organocatalytic Aldol Reaction and a Frustrated Lewis Pair

The computational study, and in particular the density functional theory (DFT) study of the organocatalytic α-chlorination-aldol reaction and the chiral backbone Frustrated Lewis Pair (FLP) system served as a valuable tool for experimental purposes. This thesis describes methods to consider different transition states of the proline- catalyzed α-chlorination aldol reaction to determine the reasonable transition state in the reaction between the enamine and α-chloro aldehydes. Moreover, the novel intramolecular Frustrated Lewis pair based on a chiral backbone for the asymmetric hydrogenation of imines and enamines was designed and the ability of hydrogen splitting by this new FLP system was examined by computational modeling and calculating the hydrogen activation energy barrier.

Mirroring Enzymes: The Role of H-Bonding In HQuin-BAM Catalyzed Asymmetric Aza-Henry Reactions: A DFT Study into the Reactivity, Mechanism, and Origins of Selectivity

The exact mechanistic understanding of various organocatalytic systems in asymmetric reactions such as Henry and aza-Henry transformations is important for developing and designing new synthetic organocatalysts. The focus of this dissertation will be on the use of density functional theory (DFT) for studying the asymmetric aza-Henry reaction. The first part of the thesis is a detailed mechanistic investigation of a poorly understood chiral bis(amidine) (BAM) Brønsted acid catalyzed aza-Henry reaction between nitromethane and N-Boc phenylaldimine. The catalyst, in addition to acting as a Brønsted base, serves to simultaneously activate both the electrophile and the nucleophile through dual H-bonding during C-C bond formation and is thus essential for both reaction rate and selectivity. Analysis of the H-bonding interactions revealed that there was a strong preference for the formation of a homonuclear positive charge-assisted H-bond, which in turn governed the relative orientation of substrate binding. Attracted by this well-defined mechanistic investigation, the other important aspect of my PhD research addressed a detailed theoretical analysis accounting for the observed selectivity in diastereoselective versions of this reaction. A detailed inspection of the stereodetermining C-C bond forming transition states for monoalkylated nitronate addition to a range of electronically different aldimines, revealed that the origins of stereoselectivity were controlled by a delicate balance of different factors such as steric, orbital interactions, and the extent of distortion in the catalyst and substrates. The structural analysis of different substituted transition states established an interesting dependency on matching the shape and size of the catalyst (host molecule) and substrates (guest molecules) upon binding, both being key factors governing selectivity, in essence, offering an analogy to positive cooperative binding effect of catalytic enzymes and substrates in Nature. In addition, both intra-molecular (intra-host) and inter-molecular (host-guest, guest-guest) stabilizing interactions play a key role to the high π-facial selectivity. The application of dispersion-corrected functionals (i.e., ωB97X-D and B3LYP-D3) was essential for accurately modeling these stabilizing interactions, indicating the importance of dispersion effects in enantioselectivity. As a brief prelude to more extensive future studies, the influence of a triflate counterion on both reactivity and selectivity in this reaction was also addressed.

Cave of the Winds, Goat Island, U.S.A.

Cave of the Winds, Goat Island, U.S.A. This is touted as the only place on the globe where rainbows form an entire circle. Geo. W. Wright is listed as the lessee. 30 cm. x 14 cm. newsprint. There is a slight wearing away of the edges. This does not affect text, n.d.

Ferry at the Falls, Niagara Falls, U.S.A.

Ferry at the Falls, Niagara Falls, U.S.A. with Geo. W. Sims at the ferry on the American shore, 31 cm. x 18 cm., May 1851.

La Facultad de Enfermería de la U.A.N.L. desde sus orígenes a la actualidad 1915-1990 : 75 años de presencia de la enfermería en el estado de Nuevo León, una visión panorámica

Tesis (Maestría en Educación Superior) UANL

Sociocultura del adolescente u autocuidado en la prevención del sida.

Tesis (Maestría en Enfermería con Especialidad en Materno Infantil Pediátrica) UANL

Identificación de posibles células del sistema A.P.U.D. en placentas humanas normales a término

Tesis (Maestría en Ciencias con Especialidad en Fisiología Médica) UANL

Los recursos humanos y los servicios de las bibliotecas universitarias : el bibliotecario y algunos servicios de las bibliotecas de las facultades de la U.A.N.L.

Tesis (Maestría en Bibliotecología) UANL

Perfil del supervisor del taller que prefieren los estudiantes de la Facultad de Trabajo Social de la U.A.N.L.

Tesis (Maestría en Trabajo Social) UANL