Alien Registration- Cullinan, Catherine A. (Portland, Cumberland County)

https://digitalmaine.com/alien_docs/25102/thumbnail.jp

Alien Registration- Cullinan, Catherine A. (Portland, Cumberland County)

https://digitalmaine.com/alien_docs/25102/thumbnail.jp

Primary Blast Traumatic Brain Injury in the Rat: Relating Diffusion Tensor Imaging and Behavior

The incidence of traumatic brain injury (TBI) among military personnel is at its highest point in U.S. history. Experimental animal models of blast have provided a wealth of insight into blast injury. The mechanisms of neurotrauma caused by blast, however, are still under debate. Specifically, it is unclear whether the blast shockwave in the absence of head motion is sufficient to induce brain trauma. In this study, the consequences of blast injury were investigated in a rat model of primary blast TBI. Animals were exposed to blast shockwaves with peak reflected overpressures of either 100 or 450 kPa (39 and 110 kPa incident pressure, respectively) and subsequently underwent a battery of behavioral tests. Diffusion tensor imaging (DTI), a promising method to detect blast injury in humans, was performed on fixed brains to detect and visualize the spatial dependence of blast injury. Blast TBI caused significant deficits in memory function as evidenced by the Morris Water Maze, but limited emotional deficits as evidenced by the Open Field Test and Elevated Plus Maze. Fractional anisotropy, a metric derived from DTI, revealed significant brain abnormalities in blast-exposed animals. A significant relationship between memory deficits and brain microstructure was evident in the hippocampus, consistent with its role in memory function. The results provide fundamental insight into the neurological consequences of blast TBI, including the evolution of injury during the sub-acute phase and the spatially dependent pattern of injury. The relationship between memory dysfunction and microstructural brain abnormalities may provide insight into the persistent cognitive difficulties experienced by soldiers exposed to blast neurotrauma and may be important to guide therapeutic and rehabilitative efforts

Knowledge practices in design: The role of visual representations as 'epistemic objects'

We use a detailed study of the knowledge work around visual representations to draw attention to the multidimensional nature of `objects'. Objects are variously described in the literatures as relatively stable or in flux; as abstract or concrete; and as used within or across practices. We clarify these dimensions, drawing on and extending the literature on boundary objects, and connecting it with work on epistemic and technical objects. In particular, we highlight the epistemic role of objects, using our observations of knowledge work on an architectural design project to show how, in this setting, visual representations are characterized by a `lack' or incompleteness that precipitates unfolding. The conceptual design of a building involves a wide range of technical, social and aesthetic forms of knowledge that need to be developed and aligned. We explore how visual representations are used, and how these are meaningful to different stakeholders, eliciting their distinct contributions. As the project evolves and the drawings change, new issues and needs for knowledge work arise. These objects have an `unfolding ontology' and are constantly in flux, rather than fully formed. We discuss the implications for wider understandings of objects in organizations and for how knowledge work is achieved in practice

A new spirometry-based algorithm to predict occupational pulmonary restrictive impairment

Background Spirometry is often included in workplace-based respiratory surveillance programmes but its performance in the identification of restrictive lung disease is poor, especially when the prevalence of this condition is low in the tested population. Aims To improve the specificity (Sp) and positive predictive value (PPV) of current spirometry-based algorithms in the diagnosis of restrictive pulmonary impairment in the workplace and to reduce the proportion of false positives findings and, as a result, unnecessary referrals for lung volume measurements. Methods We re-analysed two studies of hospital patients, respectively used to derive and validate a recommended spirometry-based algorithm [forced vital capacity (FVC) < 85% predicted and forced expiratory volume in 1 s (FEV1)/FVC > 55%] for the recognition of restrictive pulmonary impairment. We used true lung restrictive cases as a reference standard in 2×2 contingency tables to estimate sensitivity (Sn), Sp and PPV and negative predictive values for each diagnostic cut-off. We simulated a working population aged <65 years and with a disease prevalence ranging 1–10% and compared our best algorithm with those previously reported using receiver operating characteristic curves. Results There were 376 patients available from the two studies for inclusion. Our best algorithm (FVC < 70% predicted and FEV1/FVC ≥ 70%) achieved the highest Sp (96%) and PPV (67 and 15% for a disease prevalence of 10 and 1%, respectively) with the lowest proportion of false positives (4%); its high Sn (71%) predicted the highest proportion of correctly classified restrictive cases (91%). Conclusions Our new spirometry-based algorithm may be adopted to accurately exclude pulmonary restriction and to possibly reduce unnecessary lung volume testing in an occupational health setting

Adapted digital music players for individuals with severe impairments

This is the peer reviewed version of the following article: Saunders, M. D., Questad, K. A., Cullinan, T. B., & Saunders, R. R. (2011). Adapted Digital Music Players for Individuals with Severe Impairments. Behavioral Interventions : Theory & Practice in Residential & Community-Based Clinical Programs, 26(2), 10.1002/bin.327. http://doi.org/10.1002/bin.327, which has been published in final form at doi.org/10.1002/bin.327. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-ArchivingPortable music production devices, such as radios, cassette players and MP3 players have characteristics that make them less than ideal for teaching the cause-and-effect relationships that would enable children and adults with severe impairments to control them independently and appropriately. Even when adapted for control with adaptive switches, the relationship between switch closure and on-off operation results in contingency characteristics that can inhibit learning. Some solutions to these problems are described, and for those individuals who can learn with complex contingencies, some promising products are reviewed

Control of carbon nanotube stiffness via tunable fabrication process parameters that determine CNT geometry

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (leaves 122-126).This paper presents tunable process parameters that may be used to control the geometry of multi-walled carbon nanotubes (MWCNTs). The results may be used to grow MWCNTs with desired stiffness properties. This is important to devices that rely on the compliance of MWCNTs in order to achieve specific performance requirements, e.g. deflection or stiffness. Examples of these types of devices include relays, resonators and flexural bearings for small-scale actuators. It is necessary to control the stiffness of these mechanisms because the force, stroke, and device bandwidth depend upon the stiffness of the constituent MWCNTs. For a given length MWCNT, the stiffness is controlled by the MWCNT diameter and the number of walls in the MWCNT. Herein we present a growth model that was generated via statistical and experimental analysis. The diameter and number of walls are controlled by adjusting several growth parameters temperature, catalyst film thickness, and hydrocarbon concentration. The model is then used to design a growth process for specific applications. The results of these growths show that the geometry of the CNTs can be accurately controlled to within 6% of the desired geometry. Based on the measured geometries, it was estimated that the stiffness and natural frequency can be accurately controlled to within 1.5% of the desired values.y Michael A. Cullinan.S.M

Design and fabrication of precision carbon nanotube-based flexural transducers

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student submitted PDF version of thesis.Includes bibliographical references (p. 179-197).As mechanical devices move towards the nanoscale, smaller and more sensitive force and displacement sensors need to be developed. Currently, many biological, materials science, and nanomanufacturing applications could benefit from multi-axis micro- and nanoscale sensors with fine force and displacement resolutions. Unfortunately, such systems do not yet exist due to the limitations of traditional sensing techniques and fabrication procedures. Carbon nanotube-based (CNT) piezoresistive transducers offer the potential to overcome many of these limitations. Previous research has shown the potential for the use of CNTs in high resolution micro- and nanoscale sensing devices due to the high gauge factor and inherent size of CNTs. However, a better understanding of CNT-based piezoresistive sensors is needed in order to be able to design and engineer CNT-based sensor systems to take advantage of this potential. The purpose of this thesis is to take CNT-based strain sensors from the single element test structures that have been fabricated and turn them into precision sensor systems that can be used in micro- and nanoscale force and displacement transducers. In order to achieve this purpose and engineer high resolution CNT-based sensor systems, the design and manufacturing methods used to create CNT-based piezoresistive sensors were investigated. At the system level, a noise model was developed in order to be able to optimize the design of the sensor system. At the element level, a link was established between the structure of the CNT and its gauge factor using a theoretical model developed from quantum mechanics. This model was confirmed experimentally using CNT-based piezoresistive sensors integrated into a microfabricated test structure. At the device level, noise mitigation techniques including annealing and the use of a protective ceramic coating were investigated in order to reduce the noise in the sensor. From these investigations, best practices for the design and manufacturing of CNT-based piezoresistive sensors were established. Using these best practices, it is possible to increase the performance of CNT-based piezoresistive sensor systems by more than three orders of magnitude. These best practices were implemented in the design and fabrication of a multi-axis force sensor used to measure the adhesion force of an array of cells to the different material's surfaces for the development of biomedical implants. This force sensor is capable of measuring forces in the z-axis as well as torques in the [theta]x and [theta]y axis. The range and resolution of the force sensor were determined to be 84 [mu]N and 5.6 nN, respectively. This corresponds to a dynamic range of 83 dB, which closely matches the dynamic range predicted by the system noise model used to design the sensor. The accuracy of the force sensor is better than 1% over the device's full range.by Michael A. Cullinan.Ph.D

Integrable Deformations from Twistor Space

Integrable field theories in two dimensions are known to originate as defect theories of 4d Chern-Simons and as symmetry reductions of the 4d anti-self-dual Yang-Mills equations. Based on ideas of Costello, it has been proposed in work of Bittleston and Skinner that these two approaches can be unified starting from holomorphic Chern-Simons in 6 dimensions. We provide the first complete description of this diamond of integrable theories for a family of deformed sigma models, going beyond the Dirichlet boundary conditions that have been considered thus far. Starting from 6d holomorphic Chern-Simons theory on twistor space with a particular meromorphic 3-form $\Omega$, we construct the defect theory to find a novel 4d integrable field theory, whose equations of motion can be recast as the 4d anti-self-dual Yang-Mills equations. Symmetry reducing, we find a multi-parameter 2d integrable model, which specialises to the $\lambda$-deformation at a certain point in parameter space. The same model is recovered by first symmetry reducing, to give 4d Chern-Simons with generalised boundary conditions, and then constructing the defect theory.Comment: 38 pages, 1 figur

Occupational allergy to fruit flies (Drosophila melanogaster) in laboratory workers

OBJECTIVES: Drosophila melanogaster (the 'fruit fly') is commonly used in genetic research, but there is only one report of IgE-associated allergy in exposed workers. 4 newly identified cases prompted us to examine the extent of this problem in a university laboratory. Our aim in this study is to determine the prevalence and determinants of sensitisation to fruit flies in a population of exposed workers. METHODS: In a cross-sectional study, we surveyed 286 employees working in a department carrying out research involving D. melanogaster. Sensitisation was assessed by specific IgE measurement in serum and examined in relation to symptoms and to estimated exposure to fruit flies. RESULTS: The overall prevalence of specific sensitisation was 6% with a clear relationship to increasing frequency/intensity of exposure (p trend<0.001). Work-related eye/nose, chest or skin symptoms were reported by substantial proportions of participants but for most of these there was no evidence of specific sensitisation to fruit fly. The overall prevalence of any work-related symptoms and sensitisation was 2.4%, rising to 7.1% in those working in high exposure groups. CONCLUSIONS: We were able to demonstrate, for the first time, a clear exposure-response relationship between fruit fly exposure and specific sensitisation. Facilities housing fruit flies should carefully consider methods to reduce exposure levels in the workplace