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- All Subjects: psychology
- All Subjects: Biomedical Engineering
- Genre: Doctoral Dissertation
- Creators: Arizona State University
- Member of: Theses and Dissertations
Description
Family adaptation to child developmental disability is a dynamic transactional process that has yet to be tested in a longitudinal, rigorous fashion. In addition, although children with developmental delays frequently have behavior problems, not enough research has examined possible underlying mechanisms in the relation between child developmental delay, adaptation and behavior problems. In the current study, factor analysis examined how best to conceptualize the construct of family adaptation to developmental delay. Also, longitudinal growth curve modeling tested models in which child behavior problems mediated the relation between developmental risk and indices of family adaptation. Participants included 130 typically developing children and their families (Mental Development Index [MDI] > 85) and 104 children with developmental delays and their families (MDI < 85). Data were collected yearly between the ages of three and eight as part of a multi-site, longitudinal investigation examining the interrelations among children's developmental status, family processes, and the emergence of child psychopathology. Results of the current study indicated that adaptation is best conceptualized as a multi-index construct. Different aspects of adaptation changed in unique ways over time, with some facets of adaptation remaining stable while others fluctuated. Child internalizing and externalizing behavior problems were found to decrease over time for both children with developmental delays and typically developing children. Child behavior problems were also found to mediate the relation between developmental risk and family adaptation for over half of the mediation pathways. Significant mediation results indicated that children with developmental delays showed higher early levels of behavior problems, which in turn was associated with more maladaptive adaptation. These findings provide further evidence that families of children with developmental delays experience both positive and more challenging changes in their families over time. This study implies important next steps for research and clinical practice in the area of developmental disability.
ContributorsPedersen y Arbona, Anita (Author) / Crnic, Keith A (Thesis advisor) / Sandler, Irwin (Committee member) / Lemery, Kathryn (Committee member) / Enders, Craig (Committee member) / Arizona State University (Publisher)
Created2011
Description
An emerging body of literature suggests that humans likely have multiple threat avoidance systems that enable us to detect and avoid threats in our environment, such as disease threats and physical safety threats. These systems are presumed to be domain-specific, each handling one class of potential threats, and previous research generally supports this assumption. Previous research has not, however, directly tested the domain-specificity of disease avoidance and self-protection by showing that activating one threat management system does not lead to responses consistent only with a different threat management system. Here, the domain- specificity of the disease avoidance and self-protection systems is directly tested using the lexical decision task, a measure of stereotype accessibility, and the implicit association test. Results, although inconclusive, more strongly support a series of domain-specific threat management systems than a single, domain- general system
ContributorsAnderson, Uriah Steven (Author) / Kenrick, Douglas T. (Thesis advisor) / Shiota, Michelle N. (Committee member) / Neuberg, Steven L. (Committee member) / Becker, David V (Committee member) / Arizona State University (Publisher)
Created2011
Description
A dual-channel directional digital hearing aid (DHA) front-end using a fully differential difference amplifier (FDDA) based Microphone interface circuit (MIC) for a capacitive Micro Electro Mechanical Systems (MEMS) microphones and an adaptive-power analog font end (AFE) is presented. The Microphone interface circuit based on FDDA converts the capacitance variations into voltage signal, achieves a noise of 32 dB SPL (sound pressure level) and an SNR of 72 dB, additionally it also performs single to differential conversion allowing for fully differential analog signal chain. The analog front-end consists of 40dB VGA and a power scalable continuous time sigma delta ADC, with 68dB SNR dissipating 67u¬W from a 1.2V supply. The ADC implements a self calibrating feedback DAC, for calibrating the 2nd order non-linearity. The VGA and power scalable ADC is fabricated on 0.25 um CMOS TSMC process. The dual channels of the DHA are precisely matched and achieve about 0.5dB gain mismatch, resulting in greater than 5dB directivity index. This will enable a highly integrated and low power DHA
ContributorsNaqvi, Syed Roomi (Author) / Kiaei, Sayfe (Thesis advisor) / Bakkaloglu, Bertan (Committee member) / Chae, Junseok (Committee member) / Barnby, Hugh (Committee member) / Aberle, James T., 1961- (Committee member) / Arizona State University (Publisher)
Created2011
Description
Demand for biosensor research applications is growing steadily. According to a new report by Frost & Sullivan, the biosensor market is expected to reach $14.42 billion by 2016. Clinical diagnostic applications continue to be the largest market for biosensors, and this demand is likely to continue through 2016 and beyond. Biosensor technology for use in clinical diagnostics, however, requires translational research that moves bench science and theoretical knowledge toward marketable products. Despite the high volume of academic research to date, only a handful of biomedical devices have become viable commercial applications. Academic research must increase its focus on practical uses for biosensors. This dissertation is an example of this increased focus, and discusses work to advance microfluidic-based protein biosensor technologies for practical use in clinical diagnostics. Four areas of work are discussed: The first involved work to develop reusable/reconfigurable biosensors that are useful in applications like biochemical science and analytical chemistry that require detailed sensor calibration. This work resulted in a prototype sensor and an in-situ electrochemical surface regeneration technique that can be used to produce microfluidic-based reusable biosensors. The second area of work looked at non-specific adsorption (NSA) of biomolecules, which is a persistent challenge in conventional microfluidic biosensors. The results of this work produced design methods that reduce the NSA. The third area of work involved a novel microfluidic sensing platform that was designed to detect target biomarkers using competitive protein adsorption. This technique uses physical adsorption of proteins to a surface rather than complex and time-consuming immobilization procedures. This method enabled us to selectively detect a thyroid cancer biomarker, thyroglobulin, in a controlled-proteins cocktail and a cardiovascular biomarker, fibrinogen, in undiluted human serum. The fourth area of work involved expanding the technique to produce a unique protein identification method; Pattern-recognition. A sample mixture of proteins generates a distinctive composite pattern upon interaction with a sensing platform consisting of multiple surfaces whereby each surface consists of a distinct type of protein pre-adsorbed on the surface. The utility of the "pattern-recognition" sensing mechanism was then verified via recognition of a particular biomarker, C-reactive protein, in the cocktail sample mixture.
ContributorsChoi, Seokheun (Author) / Chae, Junseok (Thesis advisor) / Tao, Nongjian (Committee member) / Yu, Hongyu (Committee member) / Forzani, Erica (Committee member) / Arizona State University (Publisher)
Created2011
Description
Alzheimer's Disease (AD) is a debilitating neurodegenerative disease. The disease leads to dementia and loss of cognitive functions and affects about 4.5 million people in the United States. It is the 7th leading cause of death and is a huge financial burden on the healthcare industry. There are no means of diagnosing the disease before neurodegeneration is significant and sadly there is no cure that controls its progression. The protein beta-amyloid or Aâ plays an important role in the progression of the disease. It is formed from the cleavage of the Amyloid Precursor Protein by two enzymes - â and ã-secretases and is found in the plaques that are deposits found in Alzheimer brains. This work describes the generation of therapeutics based on inhibition of the cleavage by â-secretase. Using in-vitro recombinant antibody display libraries to screen for single chain variable fragment (scFv) antibodies; this work describes the isolation and characterization of scFv that target the â-secretase cleavage site on APP. This approach is especially relevant since non-specific inhibition of the enzyme may have undesirable effects since the enzyme has been shown to have other important substrates. The scFv iBSEC1 successfully recognized APP, reduced â-secretase cleavage of APP and reduced Aâ levels in a cell model of Alzheimer's Disease. This work then describes the first application of bispecific antibody therapeutics to Alzheimer's Disease. iBSEC1 scFv was combined with a proteolytic scFv that enhances the "good" pathway (á-secretase cleavage) that results in alternative cleavage of APP to generate the bispecific tandem scFv - DIA10D. DIA10D reduced APP cleavage by â-secretase and steered it towards the "good" pathway thus increasing the generation of the fragment sAPPá which is neuroprotective. Finally, treatment with iBSEC1 is evaluated for reduced oxidative stress, which is observed in cells over expressing APP when they are exposed to stress. Recombinant antibody based therapeutics like scFv have several advantages since they retain the high specificity of the antibodies but are safer since they lack the constant region and are smaller, potentially facilitating easier delivery to the brain
ContributorsBoddapati, Shanta (Author) / Sierks, Michael (Thesis advisor) / Arizona State University (Publisher)
Created2011
Description
When people pick up the phone to call a telephone quitline, they are taking an important step towards changing their smoking behavior. The current study investigated the role of a critical cognition in the cessation process--self-efficacy. Self-efficacy is thought to be influential in behavior change processes including those involved in the challenging process of stopping tobacco use. By applying basic principles of self-efficacy theory to smokers utilizing a telephone quitline, this study advanced our understanding of the nature of self-efficacy in a "real-world" cessation setting. Participants received between one and four intervention calls aimed at supporting them through their quit attempt. Concurrent with the initiation of this study, three items (confidence, stress, and urges) were added to the standard telephone protocol and assessed at each call. Two principal sets of hypotheses were tested using a combination of ANCOVAs and multiple regression analyses. The first set of hypotheses explored how self-efficacy and changes in self-efficacy within individuals were associated with cessation outcomes. Most research has found a positive linear relation between self-efficacy and quit outcomes, but this study tested the possibility that excessively high self-efficacy may actually reflect an overconfidence bias, and in some cases be negatively related to cessation outcomes. The second set of hypotheses addressed several smoking-related factors expected to affect self-efficacy. As predicted, higher baseline self-efficacy and increases in self-efficacy were associated with higher rates of quitting. However, contrary to predictions, there was no evidence that overconfidence led to diminished cessation success. Finally, as predicted, shorter duration of quit attempts, shorter time to relapse, and stronger urges all were associated with lower self-efficacy. In conclusion, understanding how self-efficacy and changes in self-efficacy affect and are affected by cessation outcomes is useful for informing both future research and current quitline intervention procedures.
ContributorsGoesling, Jenna (Author) / Barrera, Manuel (Thesis advisor) / Shiota, Lani (Committee member) / Enders, Craig (Committee member) / Presson, Clark (Committee member) / Arizona State University (Publisher)
Created2011
Description
In this work, a novel method is developed for making nano- and micro- fibrous hydrogels capable of preventing the rejection of implanted materials. This is achieved by either (1) mimicking the native cellular environment, to exert fine control over the cellular response or (2) acting as a protective barrier, to camouflage the foreign nature of a material and evade recognition by the immune system. Comprehensive characterization and in vitro studies described here provide a foundation for developing substrates for use in clinical applications. Hydrogel dextran and poly(acrylic acid) (PAA) fibers are formed via electrospinning, in sizes ranging from nanometers to microns in diameter. While "as-electrospun" fibers are continuous in length, sonication is used to fragment fibers into short fiber "bristles" and generate nano- and micro- fibrous surface coatings over a wide range of topographies. Dex-PAA fibrous surfaces are chemically modified, and then optimized and characterized for non-fouling and ECM-mimetic properties. The non-fouling nature of fibers is verified, and cell culture studies show differential responses dependent upon chemical, topographical and mechanical properties. Dex-PAA fibers are advantageously unique in that (1) a fine degree of control is possible over three significant parameters critical for modifying cellular response: topography, chemistry and mechanical properties, over a range emulating that of native cellular environments, (2) the innate nature of the material is non-fouling, providing an inert background for adding back specific bioactive functionality, and (3) the fibers can be applied as a surface coating or comprise the scaffold itself. This is the first reported work of dex-PAA hydrogel fibers formed via electrospinning and thermal cross-linking, and unique to this method, no toxic solvents or cross-linking agents are needed to create hydrogels or for surface attachment. This is also the first reported work of using sonication to fragment electrospun hydrogel fibers, and in which surface coatings were made via simple electrostatic interaction and dehydration. These versatile features enable fibrous surface coatings to be applied to virtually any material. Results of this research broadly impact the design of biomaterials which contact cells in the body by directing the consequent cell-material interaction.
ContributorsLouie, Katherine BoYook (Author) / Massia, Stephen P (Thesis advisor) / Bennett, Kevin (Committee member) / Garcia, Antonio (Committee member) / Pauken, Christine (Committee member) / Vernon, Brent (Committee member) / Arizona State University (Publisher)
Created2011
Description
Intuitive decision making refers to decision making based on situational pattern recognition, which happens without deliberation. It is a fast and effortless process that occurs without complete awareness. Moreover, it is believed that implicit learning is one means by which a foundation for intuitive decision making is developed. Accordingly, the present study investigated several factors that affect implicit learning and the development of intuitive decision making in a simulated real-world environment: (1) simple versus complex situational patterns; (2) the diversity of the patterns to which an individual is exposed; (3) the underlying mechanisms. The results showed that simple patterns led to higher levels of implicit learning and intuitive decision-making accuracy than complex patterns; increased diversity enhanced implicit learning and intuitive decision-making accuracy; and an embodied mechanism, labeling, contributes to the development of intuitive decision making in a simulated real-world environment. The results suggest that simulated real-world environments can provide the basis for training intuitive decision making, that diversity is influential in the process of training intuitive decision making, and that labeling contributes to the development of intuitive decision making. These results are interpreted in the context of applied situations such as military applications involving remotely piloted aircraft.
ContributorsCovas-Smith, Christine Marie (Author) / Cooke, Nancy J. (Thesis advisor) / Patterson, Robert (Committee member) / Glenberg, Arthur (Committee member) / Homa, Donald (Committee member) / Arizona State University (Publisher)
Created2011
Description
Biological membranes are critical to cell sustainability by selectively permeating polar molecules into the intracellular space and providing protection to the interior organelles. Biomimetic membranes (model cell membranes) are often used to fundamentally study the lipid bilayer backbone structure of the biological membrane. Lipid bilayer membranes are often supported using inorganic materials in an effort to improve membrane stability and for application to novel biosensing platforms. Published literature has shown that a variety of dense inorganic materials with various surface properties have been investigated for the study of biomimetic membranes. However, literature does not adequately address the effect of porous materials or supports with varying macroscopic geometries on lipid bilayer membrane behavior. The objective of this dissertation is to present a fundamental study on the synthesis of lipid bilayer membranes supported by novel inorganic supports in an effort to expand the number of available supports for biosensing technology. There are two fundamental areas covered including: (1) synthesis of lipid bilayer membranes on porous inorganic materials and (2) synthesis and characterization of cylindrically supported lipid bilayer membranes. The lipid bilayer membrane formation behavior on various porous supports was studied via direct mass adsorption using a quartz crystal microbalance. Experimental results demonstrate significantly different membrane formation behaviors on the porous inorganic supports. A lipid bilayer membrane structure was formed only on SiO2 based surfaces (dense SiO2 and silicalite, basic conditions) and gamma-alumina (acidic conditions). Vesicle monolayer adsorption was observed on gamma-alumina (basic conditions), and yttria stabilized zirconia (YSZ) of varying roughness. Parameters such as buffer pH, surface chemistry and surface roughness were found to have a significant impact on the vesicle adsorption kinetics. Experimental and modeling work was conducted to study formation and characterization of cylindrically supported lipid bilayer membranes. A novel sensing technique (long-period fiber grating refractometry) was utilized to measure the formation mechanism of lipid bilayer membranes on an optical fiber. It was found that the membrane formation kinetics on the fiber was similar to its planar SiO2 counterpart. Fluorescence measurements verified membrane transport behavior and found that characterization artifacts affected the measured transport behavior.
ContributorsEggen, Carrie (Author) / Lin, Jerry Y.S. (Thesis advisor) / Dai, Lenore (Committee member) / Rege, Kaushal (Committee member) / Thornton, Trevor (Committee member) / Vogt, Bryan (Committee member) / Arizona State University (Publisher)
Created2011
Description
In the present research, two interventions were developed to increase sun protection in young women. The purpose of the study was to compare the effects of intervention content eliciting strong emotional responses to visual images depicting photoaging and skin cancer, specifically fear and disgust, coupled with a message of self-efficacy and benefits of sun protection (the F intervention) with an intervention that did not contain an emotional arousal component (the E intervention). Further, these two intervention conditions were compared to a control condition that contained an emotional arousal component that elicited emotion unrelated to the threat of skin cancer or photoaging (the C control condition). A longitudinal study design was employed, to examine the effects of condition immediately following the intervention, and to examine sun protection behavior 2 weeks after the intervention. A total of 352 undergraduate women at Arizona State University were randomly assigned to one of the three conditions (F n = 148, E n = 73, C n = 131). Several psychosocial constructs, including benefits of sun protection, susceptibility to and severity of photoaging and sun exposure, self-efficacy beliefs of making sun protection a daily habit, and barriers to sun protection were measured before and immediately following the intervention. Sun protection behavior was measured two weeks later. Those in the full intervention reported higher self-efficacy and severity of photoaging at immediate posttest than those in the efficacy only and control conditions. The fit of several path models was tested to explore underlying mechanisms by which the intervention affected sun protection behavior. Experienced emotion, specifically fear and disgust, predicted susceptibility and severity, which in turn predicted anticipated regret of failing to use sun protection. The relationship between this overall threat component (experienced emotion, susceptibility, severity, and anticipated regret) and intentions to engage in sun protection behavior was mediated by benefits. The present research provided evidence of the effectiveness of threat specific emotional arousal coupled with a self-efficacy and benefits message in interventions to increase sun protection. Further, this research provided additional support for the inclusion of both experienced and anticipated emotion in models of health behavior.
ContributorsMoser, Stephanie E (Author) / Aiken, Leona S. (Thesis advisor) / Shiota, Michelle N. (Committee member) / Kwan, Sau (Committee member) / Castro, Felipe (Committee member) / Arizona State University (Publisher)
Created2011