Background The inducible Cre-lox system is a valuable tool to study gene function in a spatial and time restricted fashion in mouse models. This strategy relies on the limited background activity of the modified Cre recombinase (CreER) in the absence of its inducer, the competitive estrogen receptor ligand, tamoxifen. The RIP-CreER mouse (Tg (Ins2-cre/Esr1) 1Dam) is among the few available β-cell specific CreER mouse lines and thus it has been often used to manipulate gene expression in the insulin-producing cells of the endocrine pancreas. Principal Findings Here, we report the detection of tamoxifen-independent Cre activity as early as 2 months of age in RIP-CreER mice crossed with three distinct reporter strains. Significance Evidence of Cre-mediated recombination of floxed alleles even in the absence of tamoxifen administration should warrant cautious use of this mouse for the study of pancreatic β-cells.

Appropriate reactions toward emotional stimuli depend on the distribution of prefrontal attentional resources. In mid-adolescence, prefrontal top-down control systems are less engaged, while subcortical bottom-up emotional systems are more engaged. We used functional magnetic resonance imaging to follow the neural development of attentional distribution, i.e. attending versus ignoring emotional stimuli, in adolescence. 144 healthy adolescents were studied longitudinally at age 14 and 16 while performing a perceptual discrimination task. Participants viewed two pairs of stimuli – one emotional, one abstract – and reported on one pair whether the items were the same or different, while ignoring the other pair. Hence, two experimental conditions were created: 'attending emotion/ignoring abstract' and 'ignoring emotion/attending abstract'. Emotional valence varied between negative, positive, and neutral. Across conditions, reaction times and error rates decreased and activation in the anterior cingulate and inferior frontal gyrus increased from age 14 to 16. In contrast, subcortical regions showed no developmental effect. Activation of the anterior insula increased across ages for attending positive and ignoring negative emotions. Results suggest an ongoing development of prefrontal top-down resources elicited by emotional attention from age 14 to 16 while activity of subcortical regions representing bottom-up processing remains stable.

International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California / An orbiting sensor module, designed by The Johns Hopkins University Applied Physics Laboratory (JHU/APL), performed a number of significant Strategic Defense Initiative (SDI) Delta 181 program experiments. These experiments required on-orbit command and monitor operations involving a worldwide network of ground facilities. A major component was the sensor module command center (SMCC), which was designed and integrated by JHU/APL. The SMCC, located at Cape Canaveral Air Force Station (CCAFS), connected to a network of Eastern Test Range, Air Force Satellite Control Network (AFSCN), Kennedy Space Center, and Western Test Range assets. The complex nature of the mission presented numerous challenges to the design, integration, and operation of the SMCC. This paper presents a functional overview of SMCC design as well as unique aspects of supporting ground network telemetry and command operation.

The present study reconstructs psychological, linguistic and ontological aspects of Mullā Ṣadrā’s philosophy in the light of Brentano’s theory of intentionality. Brentano used intentionality as a psychological term to denote the ‘mental’ as opposed to the ‘natural’. Later, with Meinong, intentionality took an ontological commitment to assenting that ‘there are things that do not exist’. The chapters that discuss Ṣadrā’s philosophy reflect the two aspects with an investigation for the production process of intentional objects and an investigation of the status of these objects in ontology. The main aim of the research is to give an internalist and monist account for the nature of intentionality demonstrating an alternative approach to the concepts of existence and the soul. Ontologically, there is only one reality (existence) and nothing is left outside it. Accordingly, intentional objects are mental beings that are at a lower level of existence (wujūd ẓillī). The principles behind the monist ontology are: first, the gradational ontology (tashkīk) that all things are determined beings (mutamayyiz) and they are manifestations of a single reality at different levels of intensity (mutashakkik), and, second, the simplicity principle (basīṭ al-ḥaqīqa) in which existence is a simple reality that comprehends all beings whilst being the principle of multiplicity at the same time. Accordingly intentional objects are a level of existence, and share same reality. Epistemologically, all knowledge processes including external senses are regarded as internal processes in which the causal effect of the extra-mental object is reduced to being an accidental preparatory tool and faculties for the soul. Perception is always completed with the touch of imagination and the real object of perception is internally created. The soul is not the receiver of forms, but is the active agent. Moreover, the soul undergoes substantial change as the objects are being produced. The soul is then not a container of forms. It is rather the case that the forms themselves construct the soul. The last point is that knowledge is a mode of existence. This mode of being (knowledge) indeed is the very existence of the human soul. In this explanation, the soul is neither material nor immaterial per se: the soul starts her journey as a material substance and becomes more delicate and immaterial through her journey. The soul’s journey is made possible with the preparatory role of the processes of perception. Intentionality is soul’s action of creating mental forms. The products are identical to soul since soul and knowledge are identical. Consequently, intentional objects are dependent on the soul in their presence and creation.

Main objective of this study is to design a compliant mechanism with high frequency and high mechanical amplification ratio to be used for amplifying the stroke of a piezostack actuator. In this thesis, first of all, related literature is investigated and then alternative conceptual designs are established utilizing the mechanisms found in literature survey. Once best conceptual design is selected, detailed design of this mechanism is done. For detailed design of the compliant mechanism, topology optimization method is used in this study. To design the mechanism, first a design domain is defined and then a finite element model of the design domain is prepared to be used in topology optimization runs. After running the topology optimization model by using TOSCA with ANSYS, results are imported to ANSYS, where final performance of the mechanism design is checked. After finalizing design of the mechanism, it is produced and its performance is tested through experiments.

Main objective of this study is to design a compliant mechanism with high frequency and high mechanical amplification ratio to be used for amplifying the stroke of a piezostack actuator. In this thesis, first of all, related literature is investigated and then alternative conceptual designs are established utilizing the mechanisms found in literature survey. Once best conceptual design is selected, detailed design of this mechanism is done. For detailed design of the compliant mechanism, topology optimization method is used in this study. To design the mechanism, first a design domain is defined and then a finite element model of the design domain is prepared to be used in topology optimization runs. After running the topology optimization model by using TOSCA with ANSYS, results are imported to ANSYS, where final performance of the mechanism design is checked. After finalizing design of the mechanism, it is produced and its performance is tested through experiments.

In this study, application of computational fluid dynamics to ground vehicle aerodynamics was investigated. Two types of vehicle models namely, Ahmed Body and MIRA Notchback Body and their scaled models were used. A commercial software &quot / Fluent&quot / was used and the effects of implementing different turbulence models with wall functions were observed. As a result, an appropriate turbulence model was selected to use in the study. The drag forces, surface pressure distributions and wake formations were investigated in simulation of various test cases available in the literature. The study was extended to simulate the aerodynamics of the vehicles in close-following situation. The results were then compared with available wind tunnel test data.

In this thesis, design of a car door window regulator is presented. This design comprises a mechanism in order that the car door window makes a specified translational motion. First, conceptual design is carried out to obtain the best suitable concept for the design and best suitable concept comes out to be a scissor mechanism. Afterwards, detailed design of the chosen concept is given. In the detail design stage, kinematic synthesis of the mechanism is performed basically using the Cardan motion. Lastly, implementation of the design on a car door is described.

Recent investigations in nanotechnology show that carbon nanotubes (CNT) have one of the most significant mechanical, electrical and optical properties. Interactions between those areas like electrical, optical and mechanical properties are also very promising in both research and industrial fields. Those unique characteristics are built by mainly the atomistic structure of the carbon nanotubes. In this thesis, the effects of vacant atoms on single walled carbon nanotubes (SWCNT) are investigated using matrix stiffness method. In order to use this technique a linkage between structural mechanics and molecular mechanics is established. A code has been developed to construct the SWCNT with the desired chirality, extracting the vacant atoms with the corresponding atomic bonds between the neighbor nodes and calculating the effect of those vacancies on its vibrational properties. A finite element software is also utilized for validation of the code and results. In order to investigate the convergence of the effect of those vacant nodes a numerous number of analyses have been carried out with randomly positioned vacant atoms. Also consecutive vacant nodes have been positioned in order to investigate the effect on the structural properties through the length of a CNT. In addition to those, as a case study, the reduction in Young&#039 / s modulus property because of the vacancies has also been investigated and the effects are tabulated in the report. It is concluded in this study that the any amount of vacant atoms have substantial effect on modal frequencies and Young&#039 / s modulus. Chirality and the position of the vacancies are the main parameters determining the structural properties of a CNT.

This thesis study addresses the problem of overconstraint via introduction of conformal polyhedral linkages comprising revolute joints only and investigation of special geometric properties for the mobility of such overconstrained linkages. These linkages are of particular interest as deployable structures. First, planar case is issued and conditions for assembling irregular conformal polygonal linkages composed of regular and angulated scissor elements are derived. These planar assemblies are implemented into faces of polyhedral shapes and radially intersecting planes to obtain two different kind of polyhedral linkages. Rest of the thesis work relates to spatial linkages. Identical isosceles Bennett loops are assembled to obtain regular polygonal linkages and many such linkages are assembled to form polyhedral linkages. Then, Fulleroid-like linkages are presented. After these seemingly independent linkage types, Jitterbug-like linkages are introduced. Based on some observations on present linkages in the literature a definition for Jitterbug-like linkages is given first, and then a set of critical properties of these linkages are revealed. This special type of polyhedral linkages is further classified as being homothetic and non-homothetic, and geometric conditions to obtain mobile homothetic Jitterbug-like polyhedral linkages are investigated. Homohedral linkages, linkages with polyhedral supports with 3- and 4-valent vertices only, tangential polyhedral linkages are detailed as special cases and the degenerate case where all faces are coplanar is discussed. Two types of modifications on Jitterbug-like linkages are presented by addition of links on the faces and radial planes of Jitterbug-like linkages. Finally, a special class of Jitterbug-like linkages - modified Wren platforms are introduced as potential deployable structures.