56 research outputs found
ALL FIBER STRAIN SENSOR BASED ON THE LASER SELF-MIXING EFFECT
No full textWe present the development of a no-contact sensor based on the laser-self-mixing effect for the simultaneous measurement of the linear and angular (yaw and pitch) degrees-of-freedom of the motion of a moving stage. The sensor is made up of three laser diodes with integrated monitor photodiodes and a plane mirror target. The measurement principle is described and a series of experiments is performed to test the proposed method by direct comparison with a reference meter system. Finally, the sensor is tested under complex displacement to validate the feasibility of simultaneous measurements of more than one degree-of-freedom. The proposed technique makes the system easier to align with respect to the traditional interferometric systems and no further optical elements are required in the laser head except for the laser chip and its integrated photodiode, thus providing an effective compact and low-cost motion control system
The role of gut microbiota in Parkinson's disease
No full textParkinson’s disease (PD) is a neurodegenerative disorder characterized by motor
dysfunction. Non-motor symptoms including gastrointestinal (GI) dysfunction and mood
disorders (such as depression) are also particularly common. GI symptoms include constipation,
and PD patients display altered gut microbiota composition. Evidence in animal models points
towards a potential causal role for the microbiota in mediating PD pathology. However, the
constipation, medication use, and lifestyle habits of PD patients can also be expected to change
microbiota composition. In this thesis, I explore the role of the gut microbiota in PD, in terms of
the degree that it is shaped by the disease state and its ability to mediate disease symptoms.
Using a transgenic mouse model of PD that displays motor deficits, GI dysfunction, and
behavioral alterations, I assessed how broad alterations to the gut microbiota impacted the motor
and non-motor phenotype. I found that both depletion of the microbiota through antibiotics, and
a shift towards a healthy wild-type mouse microbiota, had a minimal impact on the PD-like
symptoms. This suggested that the PD-like transgenic state of this model may drive the disease
phenotype to a greater extent than the microbiota. Similarly, I demonstrated that the decreased
abundance of Lachnospiraceae and decreased abundance of Ruminococcaceae and Oscillospira
observed in PD patients may be a result of constipation by treating PD mice with laxatives that
reversed these shifts. Lachnospiraceae abundance was also found to be decreased by treatment of this model with the PD medications L-DOPA and carbidopa.
Conversely, different antibiotic treatment regimens were able to shift the microbial
community and alter GI transit time in PD mice. Specific bacterial taxa, such as Lachnospiraceae
(Ruminococcus), were associated with transit time – indicating a potential to treat PD
constipation via the microbiota. Furthermore, treatment of PD mice with PD medications had a beneficial effect on constipation and depression-like behavior, potentially through increasing the
abundance of Turicibacter and promoting butyrate production.
This thesis demonstrates that certain PD-associated microbiota alterations may be a result
of slowed GI transit or the presence of medications. However, specific shifts to the gut
microbiota may in turn mediate non-motor symptoms in PD.Medicine, Faculty ofBiochemistry and Molecular Biology, Department ofGraduat
Linear, Nonlinear, and Distributed-Parameter Observers Used for (Renewable) Energy Processes and Systems—An Overview
No full textFull- and reduced-order observers have been used in many engineering applications, particularly for energy systems. Applications of observers to energy systems are twofold: (1) the use of observed variables of dynamic systems for the purpose of feedback control and (2) the use of observers in their own right to observe (estimate) state variables of particular energy processes and systems. In addition to the classical Luenberger-type observers, we will review some papers on functional, fractional, and disturbance observers, as well as sliding-mode observers used for energy systems. Observers have been applied to energy systems in both continuous and discrete time domains and in both deterministic and stochastic problem formulations to observe (estimate) state variables over either finite or infinite time (steady-state) intervals. This overview paper will provide a detailed overview of observers used for linear and linearized mathematical models of energy systems and review the most important and most recent papers on the use of observers for nonlinear lumped (concentrated)-parameter systems. The emphasis will be on applications of observers to renewable energy systems, such as fuel cells, batteries, solar cells, and wind turbines. In addition, we will present recent research results on the use of observers for distributed-parameter systems and comment on their actual and potential applications in energy processes and systems. Due to the large number of papers that have been published on this topic, we will concentrate our attention mostly on papers published in high-quality journals in recent years, mostly in the past decade
Integrated Circuits and Logic Operations Based on Single-Layer MoS2 (vol 5, pg 9934, 2011)
No full textIE
Addendum: Small-signal amplifier based on single-layer MoS2 [Appl. Phys. Lett. 101, 043103 (2012)]
No full text
- …
