Studying Electrophoretic Separations Using Cholate Micelles: Effects Of Ph, Temperature, And Composition

Micelle-forming bile salts have previously been shown to be effective pseudo-stationary phases for separating the chiral isomers of binaphthyl compounds with micellar electrokinetic capillary chromatography (MEKC). Here, cholate micelles are systematically investigated via electrophoretic separations and NMR using R, S-1, 1¿- binaphthyl- 2, 2¿-diylhydrogenphosphate (BNDHP) as a model chiral analyte. The pH, temperature, and concentration of BNDHP were systematically varied while monitoring the chiral resolution obtained with MEKC and the chemical shift of various protons in NMR. NMR data for each proton on BNDHP is monitored as a function of cholate concentration: as cholate monomers begin to aggregate and the analyte molecules begin to sample the micelle aggregate we observe changes in the cholate methyl and S-BNDHP proton chemical shifts. From such NMR data, the apparent CMC of cholate at pH 12 is found to be about 13-14 mM, but this value decreases at higher pH, suggesting that more extreme pHs may give rise to more effective separations. In general, CMCs increase with temperature indicating that one may be able to obtain better separations at lower temperatures. S-BNDHP concentrations ranging from 50 ¿M to 400 ¿M (pH 12.8) gave rise to apparent cholate CMC values from 10 mM to 8 mM, respectively, indicating that S-BNDHP, the chiral analyte molecule, may play an active role in stabilizing cholate aggregates. In all, these data show that NMR can be used to systematically investigate a complex multi-variable landscape of potential optimizations of chiral separations.

Effects Of The Flash Welding Process On Mechanical And Microstructural Properties Of Structural Steel Joints Assessed Using Dest

ASTM A529 carbon¿manganese steel angle specimens were joined by flash butt welding and the effects of varying process parameter settings on the resulting welds were investigated. The weld metal and heat affected zones were examined and tested using tensile testing, ultrasonic scanning, Rockwell hardness testing, optical microscopy, and scanning electron microscopy with energy dispersive spectroscopy in order to quantify the effect of process variables on weld quality. Statistical analysis of experimental tensile and ultrasonic scanning data highlighted the sensitivity of weld strength and the presence of weld zone inclusions and interfacial defects to the process factors of upset current, flashing time duration, and upset dimension. Subsequent microstructural analysis revealed various phases within the weld and heat affected zone, including acicular ferrite, Widmanstätten or side-plate ferrite, and grain boundary ferrite. Inspection of the fracture surfaces of multiple tensile specimens, with scanning electron microscopy, displayed evidence of brittle cleavage fracture within the weld zone for certain factor combinations. Test results also indicated that hardness was increased in the weld zone for all specimens, which can be attributed to the extensive deformation of the upset operation. The significance of weld process factor levels on microstructure, fracture characteristics, and weld zone strength was analyzed. The relationships between significant flash welding process variables and weld quality metrics as applied to ASTM A529-Grade 50 steel angle were formalized in empirical process models.

Metacommunity Dynamics Of Benthic Macroinvertebrates In A Large River

Metacommunity ecology focuses on the interaction between local communities and is inherently linked to dispersal as a result. Within this framework, communities are structured by a combination of in-site responses to the immediate environment (species sorting), stochasticity (patch dynamics), and connections to other communities via distance between communities and dispersal (neutrality), and source-sink dynamics (mass effects; see Chapter 1 for a detailed description of metacommunity theory, the study site, and macroinvertebrate communities found). In Chapter 2 I describe spatial scale of study and dispersal ability as both have the ability to influence the degree to which communities interact. However, little is known about how these factors influence the importance of all metacommunity dynamics. I compared dispersal mode of immature aquatic insects and dispersal ability of winged adults across multiple spatial scales in a large river. The strongest drivers of river communities were patch dynamics, followed by species sorting, then neutrality. Active dispersers during aquatic lifestages on average exhibited lower patch dynamics, higher species sorting, and significant mass effects compared to passive dispersers. Active and strong dispersers also had a scale-independent influence of neutrality, while neutrality was stronger at broader spatial scale for passive and weak dispersers. These results indicate as dispersal ability increases patch dynamics decreases, species sorting increases, and neutrality should decrease. The perceived influence of neutrality may also be dependent on spatial scale and dispersal ability. In Chapter 3 I describe how river benthic macroinvertebrate communities may influence tributary invertebrate communities via adult flight and tributaries may influence mainstem communities via immature drift. This relationship may also depend on relative mainstem and tributary size, as well as abiotic tributary influence on mainstem habitat. To investigate the interaction between a larger river and tributary I sampled mainstem benthic invertebrate communities and quantified habitat of a 7th order river (West Branch Susquehanna River) above and below a 5th order tributary confluence, as well as 0.95-3.2 km upstream in the tributary. Non-metric multidimensional scaling showed similar patterns of clustering between sampling locations for both habitat characteristics and invertebrate communities. In addition, mainstem river communities and habitat directly downstream of the tributary confluence cluster tightly together, intermediate between tributary and mid-channel river samples. In Bray-Curtis dissimilarity comparisons between tributary and mainstem river communities the furthest upstream tributary communities were least similar to river communities. Middle tributary samples were also closest by Euclidean distance to the upstream mainstem riffle and exhibited higher similarity to mid-channel samples than the furthest downstream tributary communities. My results indicate river and tributary benthic invertebrate communities may interact and likely result in direct and indirect mass effects of a tributary on the downstream mainstem community by invertebrate drift and habitat restructuring via material delivery from the tributary. I also showed likely direct effects of adult dispersal from the river and oviposition in proximal tributary locations where Euclidian, rather than river, distance may be more important in determining river-tributary interactions.

The Expression Of Motor Planning In Squirrel Monkeys (Saimiri sciureus) And Brown Capuchins (Cebus apella)

Multiple recent studies provide evidence that both human and nonhuman primates possess motor planning abilities. I tested for the demonstration of motor planning in two previously untested primate species through two experiments. In the first experiment, I compared the extent to which squirrel monkeys (Saimiri sciureus) and brown capuchins (Cebus apella) plan their movements in a grasping task. Individuals were presented with an inverted cup that required being turned and held upright in order to extract a food reward from the inside of the cup. This task was most efficiently solved by using an initially awkward inverted grasp that affords a comfortable hand and arm orientation at the end of the movement (known as end-state comfort). While certain individuals from both species exhibited end-state comfort, many of the capuchins never demonstrated this type of motor planning. Furthermore, the squirrel monkeys used the efficient grasp significantly more than the capuchins. In the second experiment, I presented the capuchins with another grasping task to test if they would express motor planning abilities in a different context. Here, the capuchins were offered a dowel that was baited on either the left or right end. A radial grasp with the thumb pointing towards the baited end was considered to be the most efficient grasp because it afforded a comfortable final position. The capuchins switched hands and used an overhand radial grasp on the dowel significantly more often than not, thus demonstrating motor planning in this task. The grasps typically utilized by these two closely related species differ considerably in that capuchins are capable of exercising precision grips, whereas squirrel monkeys are limited to whole-handed power grips. Moreover, unlike capuchins, squirrel monkeys are not particularly dexterous nor are they capable of precise manipulative actions. It is therefore more beneficial for squirrel monkeys to plan their movements efficiently because they are less capable of compensating for inappropriate initial grasps. Due to the appreciable variability in the expression of motor planning skills across species, I proposed that morphological constraints might explain the observed discrepancies in movement planning among different primate species.

Ontologies and Methods for Interoperability of Engineering Analysis Models (EAMS) in an E-Design Environment

ABSTRACT ONTOLOGIES AND METHODS FOR INTEROPERABILITY OF ENGINEERING ANALYSIS MODELS (EAMS) IN AN E-DESIGN ENVIRONMENT SEPTEMBER 2007 NEELIMA KANURI, B.S., BIRLA INSTITUTE OF TECHNOLOGY AND SCIENCES PILANI INDIA M.S., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Ian Grosse Interoperability is the ability of two or more systems to exchange and reuse information efficiently. This thesis presents new techniques for interoperating engineering tools using ontologies as the basis for representing, visualizing, reasoning about, and securely exchanging abstract engineering knowledge between software systems. The specific engineering domain that is the primary focus of this report is the modeling knowledge associated with the development of engineering analysis models (EAMs). This abstract modeling knowledge has been used to support integration of analysis and optimization tools in iSIGHT FD , a commercial engineering environment. ANSYS , a commercial FEA tool, has been wrapped as an analysis service available inside of iSIGHT-FD. Engineering analysis modeling (EAM) ontology has been developed and instantiated to form a knowledge base for representing analysis modeling knowledge. The instances of the knowledge base are the analysis models of real world applications. To illustrate how abstract modeling knowledge can be exploited for useful purposes, a cantilever I-Beam design optimization problem has been used as a test bed proof-of-concept application. Two distinct finite element models of the I-beam are available to analyze a given beam design- a beam-element finite element model with potentially lower accuracy but significantly reduced computational costs and a high fidelity, high cost, shell-element finite element model. The goal is to obtain an optimized I-beam design at minimum computational expense. An intelligent KB tool was developed and implemented in FiPER . This tool reasons about the modeling knowledge to intelligently shift between the beam and the shell element models during an optimization process to select the best analysis model for a given optimization design state. In addition to improved interoperability and design optimization, methods are developed and presented that demonstrate the ability to operate on ontological knowledge bases to perform important engineering tasks. One such method is the automatic technical report generation method which converts the modeling knowledge associated with an analysis model to a flat technical report. The second method is a secure knowledge sharing method which allocates permissions to portions of knowledge to control knowledge access and sharing. Both the methods acting together enable recipient specific fine grain controlled knowledge viewing and sharing in an engineering workflow integration environment, such as iSIGHT-FD. These methods together play a very efficient role in reducing the large scale inefficiencies existing in current product design and development cycles due to poor knowledge sharing and reuse between people and software engineering tools. This work is a significant advance in both understanding and application of integration of knowledge in a distributed engineering design framework.

Effects of Externally Applied, Cyclical, Low Magnitude Forces on Orthodontic Tooth Movement in Rats

Orthodontic tooth movement requires external orthodontic forces to be converted to cellular signals that result in the coordinated removal of bone on one side of the tooth (compression side) by osteoclasts, and the formation of new bone by osteoblasts on the other side (tension side). The length of orthodontic treatment can take several years, leading to problems of caries, periodontal disease, root resorption, and patient dissatisfaction. It appears that the velocity of tooth movement is largely dependent on the rate of alveolar bone remodeling. Pharmacological approaches to increase the rate of tooth movement are limited due to patient discomfort, severe root resorption, and drug-induced side effects. Recently, externally applied, cyclical, low magnitude forces (CLMF) have been shown to cause an increase in the bone mineral density of long bones, and in the growth of craniofacial structures in a variety of animal models. In addition, CLMF is well tolerated by the patient and produces no known adverse effects. However, its application in orthodontic tooth movement has not been specifically determined. Since factors that increase alveolar bone remodeling enhance the rate of orthodontic tooth movement, we hypothesized that externally applied, cyclical, low magnitude forces (CLMF) will increase the rate of orthodontic tooth movement. In order to test this hypothesis we used an in vivo rat orthodontic tooth movement model. Our specific aims were: Specific Aim 1: To develop an in vivo rat model for tooth movement. We developed a tooth movement model based upon two established rodent models (Ren and Yoshimatsu et al, See Figure 1.). The amount of variation of tooth movement in rats exposed to 25-60 g of mesial force activated viii from the first molar to the incisor for 4 weeks was calculated. Specific Aim 2: To determine the frequency dose response of externally applied, cyclical, low magnitude forces (CLMF) for maximal tooth movement and osteoclast numbers. Our working hypothesis for this aim was that the amount of tooth movement would be dose dependent on the frequency of application of the CLMF. In order to test this working hypothesis, we varied the frequency of the CLMF from 30, 60, 100, and 200 Hz, 0.4N, two times per week, for 10 minutes for 4 weeks, and measured the amount of tooth movement. We also looked at the number of osteoclasts for the different frequencies; we hypothesized an increase in osteoclasts for the dose respnse of different frequencies. Specific Aim 3: To determine the effects of externally applied, cyclical, low magnitude forces (CLMF) on PDL proliferation. Our working hypothesis for this aim was that PDL proliferation would increase with CLMF. In order to test this hypothesis we compared CLMF (30 Hz, 0.4N, two times per week, for 10 minutes for 4 weeks) performed on the left side (experimental side), to the non-CLMF side, on the right (control side). This was an experimental study with 24 rats in total. The experimental group contained fifteen (15) rats in total, and they all received a spring plus a different frequency of CLMF. Three (3) received a spring and CLMF at 30 Hz, 0.4N for 10 minutes. Six (6) received a spring and CLMF at 60 Hz, 0.4N for 10 minutes. Three (3) received a spring and CLMF at 100 Hz, 0.4N for 10 minutes. Three (3) received a spring and CLMF at 200 Hz, 0.4N for 10 minutes. The control group contained six (6) rats, and received only a spring. An additional ix three (3) rats received CLMF (30 Hz, 0.4N, two times per week, for 10 minutes for 4 weeks) only, with no spring, and were used only for histological purposes. Rats were subjected to the application of orthodontic force from their maxillary left first molar to their left central incisor. In addition some of the rats received externally applied, cyclical, low magnitude force (CLMF) on their maxillary left first molar. micro-CT was used to measure the amount of orthodontic tooth movement. The distance between the maxillary first and second molars, at the most mesial point of the second molar and the most distal point of the first molar (1M-2M distance) were used to evaluate the distance of tooth movement. Immunohistochemistry was performed with TRAP staining and BrdU quantification. Externally applied, cyclical, low magnitude forces (CLMF) do appear to have an effect on the rate, while not significant, of orthodontic tooth movement in rats. It appears that lower CLMF decreases the rate of tooth movement, while higher CLMF increases the rate of tooth movement. Future studies with larger sample sizes are needed to clarify this issue. CLMF does not appear to affect the proliferation in PDL cells, and has no effect on the number of osteoclasts.

The Perceived Prognosis of Endodontic Treatment and Implant Therapy Among Dental Practitioners

Little data concerning the perceived success of implant therapy in comparison with endodontic treatment exists. While the criteria used to measure the outcome of each modality are not the same, it is not clear if this is appreciated by practicing dentists. The purpose of the study was to evaluate the perceived outcome of implant therapy in comparison to endodontic treatment. A 23 question Web-based survey was distributed to 648 dentists who matriculated from the University of Connecticut School Of Dental Medicine over the past 30 years. The response rate was 47%. Sixty-seven percent of respondents were general dentists. Forty-nine percent of respondents did not know different criteria exist in the literature and are used to evaluate implant and root canal treatment. Fifty-four percent of dentists felt the prognosis of implant therapy was the same as or better than endodontic treatment of teeth with vital pulps. Thirty percent of responders thought root canal treatment of teeth with necrotic pulp was superior to implants and only 16% thought retreatment was preferable. Treatment planning for implant placement vs. retreatment of a restorable tooth was 46% and 32%, respectively. A third of the respondents felt that the role of endodontics will decline in the future. Dentists’ primary source of information regarding implant therapy was continuing education; however, their primary source of information regarding endodontic treatment was their dental program. Dentists felt the prognosis of implant therapy was as good or superior to endodontic treatment of teeth with vital, necrotic or previously treated pulps.