http://idea.library.drexel.edu/handle/1860/1 Search the Channel search http://idea.library.drexel.edu/simple-search http://idea.library.drexel.edu/handle/1860/2879 Title: Understanding the lived experience of adult blood and marrow transplant patients in isolation via an art making task and verbal interview <br/> <br/>Authors: Adcock, Carrie <br/> <br/>Abstract: Blood and marrow transplants are becoming more widely used to treat a variety of diseases. Because the number of individuals that are receiving transplants is expanding, it is important to increase knowledge of what the patients may experience. Two blood and marrow transplant patients in isolation consented to participate in the study. Both participants were female and were within the age range of 18 to 70. Moustakas’ phenomenological research method was used to investigate the overall experience of the participants. Data collection consisted of two parts: non-verbal (an art making task) and verbal (an in-depth verbal interview). The study found that adult blood and marrow transplant patients in isolation are challenged mentally and physically. The artwork of the participants was analyzed the common themes found were: isolation/loneliness, anxiety, confinement, depression, need for control, dependence, isolation of affect frustration, transplant. The transcribed interviews of the participants were analyzed. Revised themes of the participants’ experiences were as follows: transformation of self, feelings of invasion, anxieties about protective confinement, and loss of autonomy and acceptance of dependence. Both patients were able to use the artwork as a non-verbal way of communicating their experience, as well as a reference tool during the verbal interview. The artwork appeared to be an effective tool to the patient to describe their experience. The findings of this study may be used as an educational tool for medical staff, mental health staff, and blood and marrow transplant patients. The findings may increase empathy and understanding for adult blood and marrow transplant patients in isolation. Finally, the results could encourage future research. http://idea.library.drexel.edu/handle/1860/2878 Title: Synthesis of polylactide with varying molecular weight and aliphatic content: effect on moisture sorption <br/> <br/>Authors: Singh, Vishesh M. <br/> <br/>Abstract: Polylactide (PLA) is a bio-based, biodegradable polymer which is derived from lactic acid and has numerous potential applications, some of which are limited by its moisture barrier and thermal properties. Prior studies have been inconsistent about how moisture sorption in PLA varies with crystallinity and molecular weight. This research is a systematic study of how moisture sorption in PLA depends on molecular weight and aliphatic content via end group modification. PLA with varying aliphatic content is achieved by initiating ring opening polymerization of Llactide with different long chain aliphatic alcohols. Molecular weight was controlled by varying the ratio of L-lactide monomer to alcohol (C16 Palmityl, C10 Decyl, C4 Butyl) initiator and triethylaluminum was used as a catalyst for precise control over molecular weight. PLA with different molecular weights and with varying end groups were synthesized and characterized by GPC, DSC, and NMR. Moisture sorption in PLA was measured with a quartz crystal microbalance (QCM). QCM experiments revealedthat both molecular weight and aliphatic content contribute to sorption properties of PLA. http://idea.library.drexel.edu/handle/1860/2877 Title: New preterm infant growth curves influence of gender and race on birth size <br/> <br/>Authors: Groveman, Sue A. <br/> <br/>Abstract: Background Adequate fetal and postnatal growth is crucial to the health of infants and significant to their future adult health. Preterm infant growth curves are used in the assessment of fetal and postnatal growth. Current growth curves, such as the Lubchenc curves, are limited by older homogenous data sets, smaller sample sizes, varying age ranges, combined-gender curves and/or disparate data sources. Evaluation of these curves was needed to determine whether a new set of curves with updated high-risk percentile classification cutoffs for preterm infants was needed. The presence of birth size differences between genders and racial groups also was important to identify and explore. Methods In the first specific aim, smoothed growth curves were created for males and females for weight, length and head circumference using a large data set (Pediatrix Medical Group). The original data included 391,681 infants (56% male; 52% white, 23% Hispanic, 15% black, 10% other) ranging from 22 to 42 weeks gestation. Infants of nonsingleton pregnancies or with ambiguous gender, congenital anomalies or physiologically improbable growth measurements were excluded. The curves were fit to the data using the LMS method. The goodness-of-fit was assessed using worm plots, z-scores, and visual inspection. The curves were validated through the evaluation of z-scores anddistribution of infants between the high-risk percentile-for-age classifications. The new curves were compared to the Lubchenco curves visually, at selected points, and via the percentages of small-for-gestational-age (SGA) and large-for-gestational-age (LGA) infants. The second specific aim investigated size differences between males and females and among racial groups. Gender differences in birth size were compared via ANOVAs, overlaid curves, specific points on the new Pediatrix curves, and distribution of infants between the high-risk percentile-for-age classifications. Racial differences in birth size were compared via ANOVAs, z-score comparisons, distribution of infants between the high-risk percentile-for-age classifications, and odds ratios. Several maternal characteristics were examined to explain the differences found in birth size by racial group (logistic regression). The sickness level of the infants was investigated to help explain group differences. Results For the first specific aim, the new Pediatrix percentiles were found to have smaller measurements than the Lubchenco curves until about 30 weeks, were somewhat similar between about 30 and 36 weeks, and were larger after 36 weeks. Overall the Lubchenco curves misclassified 15% of males and 10% of females as SGA, appropriatefor- gestational age (AGA), or LGA according to the new Pediatrix curves. For the second specific aim, males were found to be significantly larger than females in weight, length, and head circumference. A higher percentage of black infants were born earlier and were significantly smaller than Hispanic and white infants. Relative to the medians, depending on gestational age, the z-scores of black infants placed up to19 percentiles below white infants. At 32-41 weeks, black infants had two to three times the risk of white infants of being born SGA. Controlling for race, preeclampsia/eclampsia was a consistent predictor of SGA for weight, length and head circumference at all age groups and smoking was a predictor for infants born at 32-41 weeks. The prevalence of being sick (APGAR at 1 minute < 3) at birth was greater in black infants and those classified as SGA for weight. Conclusions Accurate preterm growth curves are crucial to the assessment of growth status and therefore are vital to the health of infants. This study found strong evidence for the replacement of the Lubchenco growth curves with contemporary gender-specific curves. This study also found significant differences in birth size (weight, length, and head circumference) between male and female infants and among the racial groups that warrant further investigation. http://idea.library.drexel.edu/handle/1860/2875 Title: Engineering a multifunctional scaffold for spinal cord repair <br/> <br/>Authors: Comolli, Noelle Kristine <br/> <br/>Abstract: Spinal cord injury (SCI) affects approximately 10,000 individuals in the United States every year. SCI occurs most commonly in young adults, leaving them seriously disabled for the remainder of their lives. Several potentially useful therapeutic strategies have emerged over the last decade including the use of scaffolds and bridges, delivery of neurotrophic factors, other therapeutic peptides and use of marrow stromal cells to promote neuronal regeneration and functional recovery. However, none of the current strategies have shown enough effect to move to clinical trials and no major efforts have been undertaken to test a combination of these strategies, which can potentially be synergistic, and lead to greater therapeutic effect. Therefore, a need exists to develop a multifunctional construct which can integrate multiple, promising therapeutic strategies. We propose to develop a novel, injectable scaffold containing stem cells (either adult messenchymal lineage or fetal neural lineage) and neurotrophic factors. The polymeric scaffold is a branched copolymer of poly (N-isopropylacrilamide) and poly(ethylene glycol) (PNIPAAm-PEG), which exhibits a phase transition typically between 29-320C. We hypothesize that localized, sustained, simultaneous delivery of multiple therapeutic proteins into the CNS along with an injectable polymeric-cellular scaffold creates a synergistic effect by synchronously modulating the injured environment and activating different signaling pathways. The delivery of nuerotrophic factors (specifically, NT-3 and BDNF) can be controlled by encapsulating them within biodegradable microparticles made from poly-lactic acid (PLA). By engineering this injectable hydrogel and cellular based scaffold to mimic the host tissues we can create a novel platform technology with applications in treatment of SCI and other tissue engineering applications. http://idea.library.drexel.edu/handle/1860/2874 Title: Do principles-based accounting standards matter? Evidence from the adoption of IFRS in China <br/> <br/>Authors: Hong, Yongtao <br/> <br/>Abstract: This paper compares measures of accounting quality for 654 firms that previously used rules-based Chinese GAAP and have transitioned into principles-based International Financial Reporting Standards (IFRS) adopted in China. In particular, I examine whether principles-based standards are associated with less real earnings management, less comparability, a higher variance of change in net income, a higher ratio of change in net income to change in cash flows, a significantly lower negative correlation between accruals and cash flows, more discretionary accruals, higher informative earnings about future cash flows and higher value relevance of accounting amounts than rules-based standards. The latter accounting regime fosters more check box or compliance mentality, provides more detailed implementation guidance, emphasizes more form over substance and deploys accounting treatments not based on recognizable principles compared to the principles-based standards. These differences between the two accounting regimes re likely to affect accounting quality. In an attempt to improve the quality of financial reporting in the post-Enron era, Section 108 of the Sarbanes-Oxley Act of 2002 instructs the Securities and Exchange Commission (SEC) to conduct studies on the characteristics of rules-based and principles-based standards. This request suggests that results of my study might have implications in U.S. and other countries transitioning from rules-based to principles-based IFRS. http://idea.library.drexel.edu/handle/1860/2873 Title: A parallel controller implementation for dynamic resource allocation in virtualized computing environment <br/> <br/>Authors: Ahmad, Shahab <br/> <br/>Abstract: The ability to dynamically allocate system resources in a large scale distributed system is highly desirable. Dynamically allocating system resources can significantly reduce under-utilization of system resources and reduce the power consumed by the servers. Since typical enterprise computing systems consist of hundreds of servers, it is almost impossible to manually reconfigure each system parameter for optimal performance. Prior work has shown that by posing the dynamic resource provisioning problem as one of sequential optimization, we can dynamically allocate system resources for optimal performance in a dynamic operating environment. However, a single threaded implementation of this control technique does not scale well with increasing system size. Therefore, this thesis develops a parallel controller implementation for dynamic resource allocation using the OpenMP interface. We analyze the performance of this controller in a virtualized computing environment, and show that dynamic resource allocation can lead to an average of 30% savings in energy consumption, over an uncontrolled system. Parallelizing the controller also significantly reduces its execution time overhead, by as much as 263%, a compared to single threaded implementation. http://idea.library.drexel.edu/handle/1860/2872 Title: A service-based web portal for integrated reverse engineering and program comprehension <br/> <br/>Authors: Mongan, William M. <br/> <br/>Abstract: REportal is a web-based reverse engineering portal web site that provides developers with access to a suite of reverse engineering and program comprehension tools via a web browser. REportal was designed to simplify system maintenance by supporting the addition and upgrading of tools without involving the end user. However, the software tools and server technologies used became deprecated so quickly that it was not possible to take full advantage of the architectural vision. Using a service-oriented architecture, we abstract the process ow of the system from the underlying tools, enabling a wizard-style method of adding services to the system, and simplifying maintenance through automation. This new architecture enables easy installation, deployment, and service management from the user's perspective, and easy service addition and portal maintenance from the developer's perspective. We conducted a case study involving the addition of a legacy tool to the portal as a service, and a description of the usability bene ts of a web-based portal that integrates several features for software analysis. http://idea.library.drexel.edu/handle/1860/2866 Title: Roles, expectations, and influence: high-risk behaviors among groups of emerging adults <br/> <br/>Authors: Woodson, Jennifer Christi <br/> <br/>Abstract: This study investigated the differences between younger and older college students with respect to perceptions of engaging in high-risk group behaviors. The sample consisted of 106 college students fiom Drexel University. Overall, the results did not confirm the hypotheses and revealed that (1) younger students did not report significantly higher levels of willingness to engage in high-risk behaviors compared to older students; (2) older students did not report significantly higher levels of expected risk in high-risk behaviors compared to younger students; (3) older students did not report significantly lower levels of expected benefits in high-risk behaviors compared to younger students; and (4) older students did not report significantly lower levels of expected involvement in high-risk behaviors when compared to younger students. This study supplements previous research on perceptions of expected high-risk behavior, and the present analyses revealed trends that lend support to the hypotheses. http://idea.library.drexel.edu/handle/1860/2865 Title: GPU-accelerated deformable registration of cone-beam CT images: design and implementation in the compute unified device architecture <br/> <br/>Authors: Jain, Nakul <br/> <br/>Abstract: This thesis describes a stream-processing model for the demons deformable registration algorithm, suitable for use on a graphics processing unit (GPU). The streaming version of the demons algorithm is developed using the Compute Unified Device Architecture (CUDA) and executed on NVidia‘s 8800 GTS GPU. Performance results using cone-beam CT data of a preserved swine lung indicate that the GPU-based implementation achieves a substantial speedup of 60 times when compared to an optimized reference implementation on a 2.8 GHz Intel processor. In addition, the accuracy of the GPU-based implementation was found to be excellent, with an RMS difference of less than 0.1 mm when compared with the reference implementation. http://idea.library.drexel.edu/handle/1860/2864 Title: Locomotion of magnetic objects in fluids <br/> <br/>Authors: Bhat, Shubham K. <br/> <br/>Abstract: Manipulation of magnetic objects in fluids is a promising technology for many applications including targeted drug delivery, sorting and analysis of biological objects. Most prior work employed magnetic field gradients achieving limited control over assembly and manipulation of magnetic and non-magnetic micro-particles. However, many important questions related to magnetic manipulation technology remain open. One such issue is the controllability of positioning multiple objects during manipulation. Positioning controllability of even the simplest system such as a pair of spherical beads seems to have been largely ignored. The main goal of this thesis is to begin addressing the question of controllability of multiple magnetic objects during their manipulation. Although the ultimate applications may involve many multiple objects, only two spherical linearly magnetizable beads are considered in this thesis in order to identify important issues and potential problems. As a first step, the manipulation problem is formulated using only magnetic interactions between the beads and their interactions with a simple source of external field gradient, while neglecting hydrodynamic interactions between the beads. Newtonian behavior of the fluid is assumed and effects of boundaries are also ignored. Such a model is typical in magnetic separation literature. It is demonstrated theoretically that positions of the beads are locally controllable (in a linearized system) by using uniform field as the input only when the beads are sufficiently close to each other. This analysis clearly demonstrates that magnetic interactions between the different objects is not necessarily a nuisance, but could in fact help to control the system. It also reveals that controllability is possible only in close proximity to a source of gradient. Placing the beads in close proximity to a source of gradient is not possible in many applications such as magnetically guided drug delivery. To circumvent difficulties with the gradients, the possibility of locomotion of the bead-pair system using only uniform magnetic field as the input is considered. The advantage of such a strategy is that the external magnetic field delivers energy for the movements of the beads but no net force. The inspiration for this comes from the motility of living organisms such as leukocytes and bacteria. It is known from previous work on swimming of living and artificial swimmers that hydrodynamic interactions play a critical role. For this reason, movement of beads subject to both, magnetic and hydrodynamic interactions is considered in the second part of this thesis. Using a simple model of hydrodynamic interactions, it is demonstrated theoretically that the beads can move as a pair in any desired direction and their final positions are completely controllable using only uniform magnetic field. Subsequently, the thesis focuses on experimental demonstrations of locomotion of a pair of beads using two different types of experimental set-ups. In one, the magnetic beads are suspended in a non-magnetic fluid using thin threads. In the other, a pair of non-magnetic beads is suspended in a magnetic fluid (ferrofluid). Locomotion is demonstrated experimentally in both test-beds. In fact, it is also shown that in the second system, where the beads are suspended magnetically, the direction and magnitude of locomotion agrees quantitatively with the proposed theoretical model. Thus, the main novel and useful contribution of this thesis is that it demonstrates using both, theoretical analysis and experimental validation, that positions of beads in a pair can be controlled to a significant extent using only uniform magnetic fields. On the one hand, this suggests future strategies by which positioning of more than two objects could possibly be magnetically guided and controlled. On the other, the work carried out in this thesis is likely to find direct applications even if it proves difficult to control more than two objects. One of the most exciting of such applications involves movements of two objects inside the body for the purpose of delivery of drugs, therapies, minimally invasive surgeries and others. Although the work carried out in this thesis is only the beginning for such medical applications, the results obtained so far offer a significant hope of success.