No / Isogenic mutants of Streptococcus mutans LT11, deficient in the production of the wall-associated protein antigens A and B, were generated by recombinant DNA technology. The hydrophobicity, adherence, and aggregation of the mutants were compared with those of the parent strain. These studies indicated that hydrophobicity, adherence, and saliva- or sucrose-induced aggregation were unaltered in the A- mutant but that hydrophobicity and adherence to saliva-coated hydroxylapatite were greatly reduced in the B- mutant whilst sucrose-dependent adherence and aggregation were increased. To determine whether these changes correlated with changes in the mutated gene product alone, the levels of a number of cell wall antigens were determined in each of the mutants. The loss of antigen A resulted in significantly reduced levels of wall-associated lipoteichoic acid, and loss of antigen B resulted in reductions in both antigen A and lipoteichoic acid. Data presented here thus suggest that changes in the expression of one wall antigen can have a dramatic effect on the levels of others.

Historic preservation commissions are required to review proposals of infill within historic districts. Often, this process is viewed as something that stifles an architect. What can an architect to do to both comply with the preservationists wishes and fulfill their clients desires to have an innovative new construction? An architect must look past the prescribed ways of satisfying preservation commissions requirements and fully interpret the process. / Master of Architecture

the richmond local arts museum is a vehicle to investigate a thesis concentrated on correcting the identity of a place that is lost in history. an intentional interruption to the "historic" context of richmond will transform the city. richmond's connection to the civil war will soon be diluted, as it will quickly gain recognition for its progressive actions, through the emergence of a new art and architecture. / Master of Architecture

The rapid pace of industrial growth in South Korea over the last few decades has radically altered the way people live. As the population began to shift from the countryside to the city to pursue a better life by working in manufacturing and services in lieu of agriculture, the dense urban condition began to arise as a result of this endless influx. There had been neither the time nor the technology available to take account of the occupants' comfort. Moreover, after the Korean war in 1950, many families were split apart and this caused the longing to accommodate a family together to become stronger than ever. Since the 1970's, mass production has greatly increased the availability of housing in terms of the quantity, not quality. Most new housing for the lower middle class was built as small spaces without much opportunity to enjoy interacting with neighbors or the outdoors. This study was initiated to explore the potentials of habitable spaces and to understand the importance of bringing neighborhood life back and the chance to experience nature within the constraints imposed by a limited space. As a response to the analysis of the relationship between existing housing and the city, a design element is proposed; a wall that transforms itself from a feature in an individual living space to the neighborhood and to a facet of a city. Also this study includes the investigation of different ideas and examples of using small space efficiently. / Master of Architecture

In order to predict the strength of shear wall with cold-formed steel framing members, analytical models were reviewed. Multiple analytical models were studied, as well as twenty-one connection tests were performed. The connection tests consist of 50-ksi cold-formed steel framing track, different fastening configurations, and different sheathing thicknesses (1/8" and 1/2"). No.12 screw resulted in the highest peak load of all fastening configurations, while the rivet connection had the lowest peak load. In addition, failure modes were observed after conducting the connection tests including shear in fastening, screw pullout, and bearing in the sheathing. However, only the rivet and No.10 screw fastening configurations were used in the prediction analysis of the shear wall by the elastic model. Six shear wall tests were conducted on both panels (1/2"and 1/8" thickness). After doing the comparison between the experimental and the elastic model, the percentage difference for the 1/8" and the 1/2" polymer composite panels (3''along the edge and 6''along the chord stud), was very small. It was 6.2% for the 1/8" and 2.96% for the 1/2" panels. This means the analytical model can predict the shear wall peak load. However, the percentage difference was slightly higher being 7.4% for the 1/2" polymer composite panels with 6" along the perimeter with the 12" at the chord stud. After comparing the experimental values to the predicted value of shear walls, it was concluded that this model is the most appropriate analytical method for predicting the shear wall capacity framed with cold-formed steel sheathed with polymer composite panels. Many of these configurations were used in a prototype shelter that was constructed and built at the structural testing laboratory at the University of North Texas.

L'objet de cette thèse est l'étude de la « Muraille Servienne », monument fondamental pour l’investigation et la compréhension de l’Époque archaïque. Cette recherche est principalement née de la nécessité de localiser et, en même temps, de dater le plus ancien circuit des remparts de la Rome antique. Il s’agit, en effet, d’un sujet qui est encore aujourd’hui très controversé. Ce travail a permis d’obtenir des données qui confirment l'existence de l’enceinte urbaine au VIe s. av. J.-C., conformément aux sources antiques, selon lesquelles la première enceinte de Rome fut construit par le roi Servius Tullius (578-535 av. J.-C.). La fortification de l’Époque royale présente à peu près la même extension que celle républicaine (IVe s. av. J.-C. ); ce cas fut jugé inacceptable par plusieurs experts et fut souvent utilisé comme preuve pour réfuter l'existence d'une muraille continue au VIe s. av. J.-C. : ce qui reviendrait presque à nier le développement de « La grande Roma dei Tarquini » / The aim of this research is to investigate the “Servian Wall”, a fundamental monument for the study and the comprehension of the Archaic Age. The main target of this analysis is to recognize and, at the same time, to attribute a date to the earliest city-wall of Rome. Effectively, there are still several questions and unsolved problems related to these topics. This dissertation confirms the existence of the circuit walls of Rome in the VIth BC, in accordance with literary sources: the earliest city-wall, indeed, is traditionally attributed to the king Servius Tullius (578-535 BC) by ancient authors. The extension of the archaic fortification almost corresponded to those of the Republican walls (IVth century BC); this matter is considered unacceptable by different scholars, who usually exploited it as an evidence to refute the existence of a circuit wall during the VIth BC.: a theory that would deny, indirectly, the well-known development of the so called “Grande Roma dei Tarquini” / Questo lavoro è iniziato sulla base di ricerche storico-archeologicheche svolgo su Roma Antica, in special modo nel periodo compreso fra l’EtàArcaica e il primo secolo della Repubblica. Le ricerche e le scopertearcheologiche degli ultimi decenni hanno modificato radicalmente il quadrodelle conoscenze relative a questo periodo, e il presente lavoro intendeapprofondire lo studio della più antica cinta di Roma. La storia di Roma è,infatti, anche quella delle sue mura: come linea tangibile che racchiude lacittà in uno spazio predeterminato e sacralizzato, fatto che condiziona i limitidella città stessa, determinando conseguenze non solo puramente praticheed utilitarie, ma anche religiose ed istituzionali.Tale ricerca è nata principalmente da una necessità: quella diindividuare e al tempo stesso datare la prima cinta dell’Urbs. Questiargomenti, infatti, costituiscono ancora oggi un tema dibattuto, e nondefinitivamente risolto. Fra gli studiosi che si sono occupati dell’argomento, ineffetti, molti affermano l’esistenza di un circuito murario arcaico,coerentemente con quanto tramandato dalle fonti letterarie, che insistonosulla costruzione di un’opera di una cinta attribuita ai Tarquini, ed inparticolare a Servio Tullio; sarebbe questa la prima cinta di Roma, che i restiin tufo locale (cappellaccio) potranno confermare. Viceversa altri studiosinegano una fortificazione arcaica, e costoro fanno risalire la prima cinta diRoma al IV secolo a.C., unanimemente riconosciuta nei tratti in blocchi digrotta oscura, un materiale che prende il nome dalle cave di estrazione,presso la località di Grotta Oscura, situata a Nord di Roma. Anche aquest’ultima cerchia si attribuisce il nome di “Mura serviane” (pur essendo dietà repubblicana), poiché in passato veniva assimilata all’opera di Servio196Tullio citata dalle fonti, e la tradizione di questa denominazione si mantieneanche oggi.Il lavoro che qui presento “MURUS SERVII. La fase arcaica delle muradi Roma”, intende considerare l’esistenza di una cinta di età regia, in accordocon la tradizione letteraria, attraverso la documentazione di tutti i reperti incappellaccio a questa riferibili. L’approccio metodologico prevede l’analisi elo studio di tali resti, contemporaneamente all’esame delle fonti letterarie e ditutta la documentazione storico-archeologica, al fine di cercare di risolvere inmaniera definitiva la questione della datazione, e per proporre unaricostruzione del circuito murario in Età arcaica.I tratti di mura in cappellaccio sono stati studiati in manierasistematica, attraverso l’analisi dei dati disponibili: archeologici, topografici,storici e letterari; fonti d’archivio, carte archeologiche e altri tipi didocumentazione; fotografie, disegni, manoscritti etc.; esame in situ nel casodi resti accessibili.

Plants colonised land 460 million years ago and charophytes represent the closest living relatives of land plants. The ability to live on land may depend on the presence of certain cell wall polysaccharides such as xyloglucan, a hemicellulose exclusively found in land plants (Popper and Fry, 2003). The cell walls of charophytes are poorly characterised. The aim of this project was to use biochemical techniques to characterise the cell wall polysaccharides of charophytic algae in relation to early land plant phylogeny. Hydrolysis of Coleochaete scutata and Chara vulgaris cell walls in 2 M trifluoroacetic acid yielded predominantly GalA, Gal, Glc and Man residues and also some Ara, Xyl and traces of Fuc and Rha. In addition, hydrolysis of Chara pectin revealed an abundance of an unusual monosaccharide, 3-O-methyl-D-galactose, which was structurally identified by a series of 1-D and 2D NMR spectroscopy by COSY, TOCSY, NOESY and HSQC. 3-O-Methyl-D-galactose is more commonly found in lycophyte cell walls where its presence has been suggested to be related to lycophytes’ evolutionarily isolated position (Popper et al., 2001). The newly discovered presence of 3-O-methyl-D-galactose in charophyte pectin suggests that this polymer may be more complex than previously thought. Coleochaete and Chara hemicellulose extracts were fractionated by anion-exchange chromatography into five classes. A strongly anionic fraction from Chara hemicellulose was found to be rich in Glc, Xyl, Gal and Fuc suggestive of a xyloglucan-like polysaccharide. However, XEG was unable to produce diagnostic xyloglucan oligosaccharides in either Coleochaete or Chara hemicelluloses. Xylanase and mannanase digestion of Coleochaete and Chara hemicelluloses gave xylan- and mannan-oligosaccharides. Furthermore, lichenase digestion of Coleochaete hemicellulose yielded an unusual octasaccharide composed of approximately equimolar xylose and glucose. My work has shown that charophyte cell walls are a source of undiscovered monosaccharides and potentially novel pectic and hemicellulosic domains which may have important functions in enabling the successful colonisation of land by plants.

El presente trabajo de investigación tiene como objetivo ejecutar el diseño del pique inclinado en 30° como proyecto para la profundización de la Veta Julie 2 en la Unidad Santa María de la Cía. Minera Poderosa S.A. con la finalidad de extraer las reservas de mineral existentes en los niveles inferiores. Actualmente el método de explotación empleado es Long Wall (variante del Open Stoping), y la extracción de mineral y desmonte en los niveles inferiores se realiza mediante el uso del winche. El sistema de extracción consistirá principalmente en ejecutar un pique inclinado para transportar material de mineral o desmonte en su totalidad desde el nivel inferior a ejecutar Nv. 2660 hacia el Nv. 2410 por donde será evacuado todo el material usando locomotora y carros mineros hacia la superficie, utilizando el izaje con winche. La ejecución de la construcción será de acuerdo al diseño del pique inclinado, el ciclo de trabajo del izaje y el cálculo de la capacidad del motor del winche eléctrico requerido, para el transporte se determina de acuerdo a las especificaciones técnicas del motor de las locomotoras a utilizar y la construcción de las estaciones del pique de acuerdo al diseño en interior mina. Las actividades de izaje y transporte, el planeamiento operativo de la mina en la construcción del pique inclinado con la finalidad de extraer es la otra etapa, asignando los recursos necesarios de acuerdo a la secuencia de los ciclos de trabajo en las actividades a ejecutar. Asimismo, se desarrolla el planeamiento de infraestructura del pique inclinado con fines de extracción de acuerdo a un cronograma de actividad, costos de operación y de capital.

Tieback walls are typically design based on predetermined pressure distribution; however, these pressures were proposed based on performance of excavations. For retaining walls used in slope remediation, the application of these pressures might not be adequate; the construction procedure; therefore, a different response of the wall is expected. This document, presents the performance of two tieback walls installed in a shale stratum. Monitored responses is correlated with construction activities; these activates implied excavation and backfilling in both of the tieback walls. In addition, this research shows a numerical procedure to evaluate the anchor capacity based on the t- z approach. Finally, this study introduces an empirical method to estimate lateral wall deformation profiles and internal bending moments along a retaining wall installed in a clay stratum.

The aim of this thesis is three-fold: i) to investigate the performance of both the Eulerian-Lagrangian model and the Eulerian-Eulerian model to simulate the turbulent gas-particle flow; ii) to investigate the indoor airflows and contaminant particle flows using the Eulerian-Lagrangian model; iii) to develop and validate particle-wall collision models and a wall roughness model for the Eulerian-Lagrangian model and to utilize these models to investigate the effects of wall roughness on the particle flows. Firstly, the Eulerian-Lagrangian model in the software package FLUENT (FLUENT Inc.) and the Eulerian-Eulerian model in an in-house research code were employed to simulate the gas-particle flows. The validation against the measurement for two-phase flow over backward facing step and in a 90-degree bend revealed that both CFD approaches provide reasonably good prediction for both the gas and particle phases. Then, the Eulerian-Lagrangian model was employed to investigate the indoor airflows and contaminant particle concentration in two geometrically different rooms. For the first room configuration, the performances of three turbulence models for simulating indoor airflow were evaluated and validated against the measured air phase velocity data. All the three turbulence models provided good prediction of the air phase velocity, while the Large Eddy Simulation (LES) model base on the Renormalization Group theory (RNG) provided the best agreement with the measurements. As well, the RNG LES model is able to provide the instantaneous air velocity and turbulence that are required for the evaluation and design of the ventilation system. In the other two-zone ventilated room configuration, contaminant particle concentration decay within the room was simulated and validated against the experimental data using the RNG LES model together with the Lagrangian model. The numerical results revealed that the particle-wall coll ision model has a considerable effect on the particle concentration prediction in the room. This research culminates with the development and implementation of particle-wall collision models and a stochastic wall roughness model in the Eulerian-Lagrangian model. This Eulerian-Lagrangian model was therefore used to simulate the gas-particle flow over an in-line tube bank. The numerical predictions showed that the wall roughness has a considerable effect by altering the rebounding behaviours of the large particles and consequently affecting the particles motion downstream along the in-line tube bank and particle impact frequency on the tubes. Also, the results demonstrated that for the large particles the particle phase velocity fluctuations are not influenced by the gas-phase fluctuations, but are predominantly determined by the particle-wall collision. For small particles, the influence of particle-wall collisions on the particle fluctuations can be neglected. Then, the effects of wall roughness on the gas-particle flow in a two-dimensional 90-degree bend were investigated. It was found that the wa ll roughness considerably altered the rebounding behaviours of particles by significantly reducing the 'particle free zone' and smoothing the particle number density profiles. The particle mean velocities were reduced and the particle fluctuating velocities were increased when taking into consideration the wall roughness, since the wall roughness produced greater randomness in the particle rebound velocities and trajectories.