108 research outputs found
Patent litigation issues
Patent Issues Relative to Life Sciences R&D - Moving from Discovery in Academia to Commercialization PanelJoe Mahoney addressed issues of patent law and patent infringement, citing several examples from the pharmaceutical industry
Design of quantum dot electroabsorption modulators for next-generation data and telecommunications
The work presented in this thesis investigates the characterisation and optimisation of InAs quantum dots for the purpose of electro-absorption modulators. The modulator is a crucial component of the next generation of integrated circuits using photonics for lower power-consumption and faster data transfer speeds.
Initial studies measuring the quantum confined Stark effect in undoped and p-modulation doped InAs QD stacks highlighted an enhanced red-shift and increase in ground state absorption strength in the p-doped structure due to carrier blocking effects. The potential modulation performance was quantified with a standard figure of merit. The figure of merit, defined as the change in absorption for a given voltage swing over the absorption at 1V showed that the p-doped QD stacks had an improvement of as much as four times that of the undoped QD when applying a 9V swing between 21 to 100 degrees Celsius. The same level of improvement was observed in the p-doped sample using a 4V swing at -73 degrees Celsius. This suggests the suitability of p-doped QDs for modulation in high or low temperature environments.
Further optimisation of the QD electro-absorption modulator was carried out using various simulation techniques. Schrodinger-Poisson models were used to get initial agreements between the model and the aforementioned measurement results. This model was then used to adjust various aspects of the QD stack to determine the optimum configuration for the modulator. The optimal configuration was found to use 7 QD layers, with a stepped doping profile within the p and n-cladding. This configuration led to an estimated 20 percent improvement in RC-bandwidth whilst having a negligible effect on the QCSE of the stack. This will enable high performance, low power consumption modulators for next generation data-communications. A brief study into using total-internal reflection (TIR) mirrors to couple light from the QD III-V stacks to Silicon waveguides was carried out. The work showed potential for efficient, compact coupling of the light. Simulations produced using 3D FDTD found that the optimised system involved using 45 degree angled reflectors for both the active and passive sections. The effect misalignment of the TIR's in both the x and y-axis on coupling performance showed a reasonable degree of tolerance when considering accuracy of typical fabrication techniques to both the overlap and relative confinement within the QD core compared to the expected TE mode profile
Visual-Somatosensory Integration and Quantitative Gait Performance in Aging
Background: The ability to integrate information across sensory modalities is an integral aspect of mobility. Yet, the association between visual-somatosensory (VS) integration and gait performance has not been well-established in aging.Methods: A total of 333 healthy older adults (mean age 76.53 ± 6.22; 53% female) participated in a visual-somatosensory simple reaction time task and underwent quantitative gait assessment using an instrumented walkway. Magnitude of VS integration was assessed using probability models, and then categorized into four integration classifications (superior, good, poor, or deficient). Associations of VS integration with three independent gait factors (Pace, Rhythm, and Variability derived by factor analysis method) were tested at cross-section using linear regression analyses. Given overlaps in neural circuitry necessary for both multisensory integration and goal-directed locomotion, we hypothesized that VS integration would be significantly associated with pace but not rhythm which is a more automatic process controlled mainly through brainstem and spinal networks.Results: In keeping with our hypothesis, magnitude of VS integration was a strong predictor of pace (β = 0.12, p < 0.05) but not rhythm (β = −0.01, p = 0.83) in fully-adjusted models. While there was a trend for the association of magnitude of VS integration with variability (β = −0.11, p = 0.051), post-hoc testing of individual gait variables that loaded highest on the variability factor revealed that stride length variability (β = −0.13, p = 0.03) and not swing time variability (β = −0.08, p = 0.15) was significantly associated with magnitude of VS integration. Of the cohort, 29% had superior, 26% had good, 29% had poor, and 16% had deficient VS integration effects.Conclusions: Worse VS integration in aging is associated with worse spatial but not temporal aspects of gait performance
The evolution of mild parkinsonian signs in aging
The progression of mild parkinsonian signs in the absence of idiopathic Parkinson's disease in aging is unclear. This study aims to identify predictors of the evolution of mild parkinsonian signs in non-dementedolder adults. Two hundred ten participants (76.25±7.10years, 57% women) were assessed at baseline and 1-year follow-up. Mild parkinsonian signs were defined as the presence of bradykinesia, rigidity and/or rest tremor. Depending upon the presence of these features at baseline and follow-up, participants were divided into one of four groups (no, transient, persistent or new-onset mild parkinsonian signs). Physical function was assessed using gait velocity. Ninety-five participants presented with mild parkinsonian signs at baseline. At 1-year follow-up, 59 demonstrated persistent mild parkinsonian signs, while 36 recovered (i.e., transient). Participants with persistent mild parkinsonian signs were older (79.66±7.15 vs. 75.81±7.37years, p=0.01) and evidenced slower gait velocity (90.41±21.46 vs. 109.92±24.32cm/s, p<0.01) compared to those with transient mild parkinsonian signs. Gait velocity predicted persistence of mild parkinsonian signs, even after adjustments (OR: 0.96, 95% CI: 0.94-0.98). Fifty-five participants demonstrated new-onset of mild parkinsonian signs. In comparison to participants without mild parkinsonian signs, presence of cardiovascular but not cerebrovascular disease at baseline was associated with new-onset mild parkinsonian signs. Our study reveals that gait velocity was the main predictor of persistent mild parkinsonian signs, whereas cardiovascular disease was associated with new-onset mild parkinsonian signs. These findings suggest a vascular mechanism for the onset of mild parkinsonian signs and a different mechanism, possibly neurodegenerative, for the persistence of mild parkinsonian signs
Social Integration and the Mental Health of Black Adolescents
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106936/1/cdev12182.pd
Techniques for Rehabilitating Pavements Without Overlays - A Systems Analysis Vol. 2 Appendixes
DOT-FH-11-9142The objective of the study was to determine the feasibility of a variety of innovative techniques for rehabilitating pavements without using thick overlays and to develop these techniques to the point where they could be implemented. A total of 39 potential techniques were identified. To determine their feasibility a systems decision analysis computer program was developed which utilizes utility theory to simultaneously consider 17 different decision criteria under four main attributes (Cost, Performance, Energy and Impact). Using this utility decision analysis program, a total of 19 techniques demonstrated the capability of solving certain problems better than currently used techniques. Included in the 19 promising techniques are a) use of rejuvenating agents for flexible pavements, b) horizontally-bored sleeper slab and joint restoration for rigid pavements, c) precast joint assemblies for rigid pavements. d) change the location of lane markings, and e) reworked surface of flexible pavement. For other specific problems the program indicated presently used techniques are better than any of the potential techniques. And finally. the program I revealed that 15 potential techniques did not show any promise at this time. Suggestions for further development, implementation and research have been made
Visual-somatosensory integration (VSI) as a novel marker of Alzheimer’s disease: A comprehensive overview of the VSI study
Identification of novel, non-invasive, non-cognitive based markers of Alzheimer’s disease (AD) and related dementias are a global priority. Growing evidence suggests that Alzheimer’s pathology manifests in sensory association areas well before appearing in neural regions involved in higher-order cognitive functions, such as memory. Previous investigations have not comprehensively examined the interplay of sensory, cognitive, and motor dysfunction with relation to AD progression. The ability to successfully integrate multisensory information across multiple sensory modalities is a vital aspect of everyday functioning and mobility. Our research suggests that multisensory integration, specifically visual-somatosensory integration (VSI), could be used as a novel marker for preclinical AD given previously reported associations with important motor (balance, gait, and falls) and cognitive (attention) outcomes in aging. While the adverse effect of dementia and cognitive impairment on the relationship between multisensory functioning and motor outcomes has been highlighted, the underlying functional and neuroanatomical networks are still unknown. In what follows we detail the protocol for our study, named The VSI Study, which is strategically designed to determine whether preclinical AD is associated with neural disruptions in subcortical and cortical areas that concurrently modulate multisensory, cognitive, and motor functions resulting in mobility decline. In this longitudinal observational study, a total of 208 community-dwelling older adults with and without preclinical AD will be recruited and monitored yearly. Our experimental design affords assessment of multisensory integration as a new behavioral marker for preclinical AD; identification of functional neural networks involved in the intersection of sensory, motor, and cognitive functioning; and determination of the impact of early AD on future mobility declines, including incident falls. Results of The VSI Study will guide future development of innovative multisensory-based interventions aimed at preventing disability and optimizing independence in pathological aging
2022 Summary of Special Pavement Test Sections
WSDOT continued to collect rutting/wear and smoothness information on a number of completed studies. This report summarizes those studies. \u2022 Open Graded Friction Courses: OGFC-AR on I-405 was more susceptible to wear than either OGFC-SBS or HMA matching the pattern seen in the I-5 and SR-520 quieter pavement test sections. \u2022 Concrete Performance and Wear. The I-82 next generation concrete surface (NGCS) sections are showing slightly more wear than the adjacent diamond ground PCC pavement after nine years of traffic. The longitudinal tining section on I-90 is currently showing slightly more wear than the adjacent diamond ground concrete; however, the difference is insignificant given the higher traffic on the longitudinal tined section. The wear on the I-90 polyester polymer concrete is similar but slightly higher than wear in the adjacent diamond ground concrete after seven years of traffic. The higher design flexural strength mixes for the SR-395 SPS-2 rigid pavement sections were the most resistant to studded tire wear. PCC paved on permeable asphalt treated base or dense graded aggregate base exhibited the best performance over lean concrete base. The I-90 Argonne to Sullivan Road project results have some similarities to the sections on SR-395. The I-90Lanes 1 and 3 (which had lower traffic) results are similar but a bit higher than the wear rates associated with the lower strength sections on SR-395. For the high traffic I-90 Lane 2, the range is higher due to the higher studded tire traffic. The findings in this report continue to influence policy decisions that are documented in WSDOT\u2019s Pavement Policy
Does cognitive training improve mobility, enhance cognition, and promote neural activation?
A close inter-relationship between mobility and cognition is reported in older adults, with improvements in gait performance noticeable after cognitive remediation in frail individuals. The aim of this study was to evaluate the efficacy of computerized cognitive training (CCT) on mobility in healthy, independently living older adults, and to determine whether CCT is associated with changes in neural activation for mobility-related brain processes. Using a randomized single-blind control design, sixty-three non-demented adults age 60 y and older (mean age = 67 y76% female, mean Montreal Cognitive Assessment [MoCA] score = 27) were recruited from a local Senior Activity Center. Participants were randomly assigned to either a 2-month CCT program (8 weeks, 3x/week, 40 min/session) or a wait-list control group. Primary outcome was self-selected gait speed during single- and dual-task walking. Secondary outcome was executive function on Trail Making Test (TMT), Part B. Neural activity was assessed via electroencephalography/event-related potentials (EEG/ERPs) targeting lower-limb performance. Results from a linear mixed effect model, adjusted for baseline MoCA score, age, gender, and study completion revealed that compared to controls, CCT improved gait speed during the dual-task (p = 0.008) but not during the single-task walking condition (p = 0.057). CCT also improved executive function (p = 0.024). Further, shorter foot reaction time responses (p = 0.019) were found with enhanced neural activation over sensorimotor areas, with shorter ERP latencies during the P2 component (p = 0.008) and enhanced motor responses (p = 0.009) also evident in the CCT group after the intervention. Overall, the electrophysiological findings suggest possible neural adaptations that could explain improvements in mobility and executive functions associated with CCT in healthy older adults
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