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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
641

Composite RCS frame systems: construction and peformance

Steele, John Phillip 30 September 2004 (has links)
The objective of this research program is to further evaluate the performance and constructability of reinforced concrete (RC) column-steel beam-slab systems (RCS) for use in low- to mid-rise space frame buildings located in regions of high wind loads and/or moderate seismicity. To better understand these systems, two full scale RCS cruciform specimens were tested under bidirectional quasi-static reversed cyclic loading. The experimental portion of this research program included the construction and testing of two full-scale cruciform specimens with identical overall dimensions but with different joint detailing. The two joint details evaluated were joint cover plates and face bearing plates with localized transverse ties. The construction process was recorded in detail and related to actual field construction practices. The specimens were tested experimentally in quasi-static reversed cyclic loading in both orthogonal loading directions while a constant axial force was applied to the column, to simulate the wind loads in a subassembly of a prototype building. To compliment the experimental work, nonlinear analyses were performed to evaluate the specimen strength and hysteretic degradation parameters for RCS systems. In addition, current recommendations in the literature on the design of RCS joints were used to estimate specimen joint strength and were compared with the experimental findings.
642

Identifying Target Genes related to Respiratory Network Dysfunction in a Mouse Model for the Rett Syndrome

Vogelgesang, Steffen 19 November 2012 (has links)
Das Rett Syndrom (RTT) gehört zu den tiefgreifenden Entwicklungsstörungen des Gehirns von dem fast ausschließlich Mädchen betroffen sind (ICD-10, F84.10). Ursächlich für die Pathogenese sind Mutationen im X-chromsomalen MECP2-Gen, welches für den Transkriptionsfaktor Methyl-CpG binding protein 2 (MeCP2) kodiert. Unterschiedliche neurologische Symptome treten zwischen 6 und 18 Monaten nach der Geburt auf, wobei schwere Rhythmussstörungen der Atmung für ein Viertel plötzlicher Todesfälle bei Rett-Patientinnen verantwortlich gemacht werden. Der neuronale Atmungsrhythmus bei Säugern wird in verschieden Regionen des ponto-medullären Hirnstammes generiert, wobei der Prä-Bötzinger Komplex als essentiell für die Rhythmogenese der Atmung angesehen wird. Mittels Genexpressionsstudien in der Ventralen Respiratorischen Gruppe (VRG), die den Prä-Bötzinger-Komplex einschließt, zeigte sich eine massiv erhöhte, pathologische Expression des Serotoninrezeptor 5B sowohl auf mRNA-, als auch auf Proteinebene bei MeCP2-defizienten Mäusen zum postnatalen Entwicklungstag P40. Der Serotoninrezeptor 5B (5-HTR5B) gehört zur Klasse der G-Protein-gekoppelten Rezeptoren. Durch detaillierte Analysen des 5-HTR5B-Proteins konnte eine natürliche Trunkierung des Rezeptors nachgewiesen werden. Des Weiteren wurde eine ungewöhnliche intrazelluläre Lokalisierung in Membranen von vesikulären und tubulären Kompartimenten beobachtet. Trotz dieser ungewöhnlichen Eigenschaften besitzt der Rezeptor weiterhin die Fähigkeit, das inhibitorische G-Protein Gαi3 konstitutiv zu aktivieren und somit den Anstieg von cAMP zu verhindern. Durch genetisches Ausschalten des 5-HTR5B Proteins (knockout) konnte gezeigt werden, dass die durch 5-HTR5B-verminderte cAMP-Konzentration in der VRG ursächlich für den gestörten Atmungsrhythmus MeCP2-defizienter Mäuse ist. Die sich aus diesen Ergebnissen ableitende pharmakologische Strategie, die cAMP Konzentration zu erhöhen, führte zu einem deutlich verbesserten Atmungsrhythmus. Die Ergebnisse dieser Arbeit implizieren neue Therapieansätze zur Behandlung der Atmungs-störungen von Rett-Patienten.
643

THE IMPACT OF A CYCLIC FEEDING REGIME ON THE EXPRESSION OF GENES INVOLVED IN APPETITE REGULATION AND LIPID METABOLISM IN RAINBOW TROUT (ONCORHYNCHUS MYKISS)

Richardson, Cameron 21 December 2011 (has links)
The purpose of this study was to investigate whether a cyclic feeding regime alters growth, lipid content and the expression of genes involved in appetite regulation and lipid metabolism in rainbow trout (Onchorynchus mykiss). Progeny from two lots of diallel crosses were raised under a daily fed control or a cyclic feeding regime containing alternating reduced and compensatory rations. Although the cyclic feeding regime did not improve overall growth, there was some degree of compensatory growth seen during re-alimentation, and the reduced ration led to sustained reductions in condition factor and muscle fat content. Appetite-regulating genes showed little or no differences in expression between feeding regimes. However, the lipid metabolism genes involved in fatty acid synthesis and muscle lipid uptake showed differences in expression during reduced and compensatory ration. This study helps to clarify optimal cyclic feeding regimes in order to enhance growth characteristics preferential to the fish culture industry. / NSERC Strategic Grant, OMAFRA
644

Design and Implementation of a Low-Power SAR-ADC with Flexible Sample-Rate and Internal Calibration

Lindeberg, Johan January 2014 (has links)
The objective of this Master's thesis was to design and implement a low power Analog to Digital Converter (ADC) used for sensor measurements. In the complete measurement unit, in which the ADC is part of, different sensors will be measured. One set of these sensors are three strain gauges with weak output signals which are to be pre-amplified before being converted. The focus of the application for the ADC has been these sensors as they were considered a limiting factor. The report describes theory for the algorithmic and incremental converter as well as a hybrid converter utilizing both of the two converter structures. All converters are based on one operational amplifier and they operate in repetitive fashions to obtain power efficient designs on a small chip area although at low conversion rates. Two converters have been designed and implemented to different degrees of completeness. One is a 13 bit algorithmic (or cyclic) converter which uses a switching scheme to reduce the problem of capacitor mismatch. This converter was implemented at transistor level and evaluated separately and to some extent also with sub-components. The second converter is a hybrid converter using both the operation of the algorithmic and incremental converter to obtain 16 bits of resolution while still having a fairly high sample rate.
645

Optimization, adaptation and application of protein misfolding cyclic amplification to detection of prions in blood plasma

Braithwaite, Shannon Lynn Unknown Date
No description available.
646

Preparation of para-disubstituted benzenes, formation of optically pure cyclic amines by intramolecular conjugate displacement and total synthesis of marinopyrrole B

Cheng, Ping Unknown Date
No description available.
647

Welding of light gauge infill panels for steel plate shear walls

Neilson, David Andrew Hunter Unknown Date
No description available.
648

The effects of cyclic guanosine 3', 5'-monophosphate analog on protein accumulation in adult rat cardiomyocytes in vitro /

Li, Ying, 1972, Mar. 31- January 2007 (has links)
Cyclic guanosine 3', 5'-monophosphate (cGMP) has recently emerged as an endogenous regulator for controlling or reversing cardiac hypertrophy. Increased protein accumulation is a key feature of cardiac hypertrophy; thus, our study investigates the effects of a cGMP analog on protein accumulation in primary culture of adult rat cardiomyocytes and dissects out the mechanisms involved. We confirmed that a cGMP analog, 8-bromo-cGMP, inhibits phenylephrine (PE)-increased accumulation of newly synthesized proteins in cultured adult rat ventricular cardiomyocytes. Firstly, we have obtained data showing that 8-bromo-cGMP does not inhibit phosphorylation of S6K1 by PE during short time treatment (10 min to 2 h), but blocks phosphorylation of S6K1 by PE at 6 h; moreover this blocking effect is completely abolished by phosphatase inhibitor Tautomycin. Then, we have demonstrated that PE and cGMP induce sustained and transient increased phosphorylation of ERK, respectively. Moreover, cGMP inhibits PE-induced phosphorylation of ERK during long term treatment (3 and 6h). We have also shown that 8-bromo-cGMP inhibits ROS generation induced by PE. Other effects of PE that could be related to hypertrophy (i.e. increased concentration of upstream binding factor mRNA and decreased concentration of the mRNAs of Atrogin and muscle specific RING finger) were not abolished by 8-bromo-cGMP. We conclude that cGMP analog blocks protein accumulation by inhibiting the sustained phosphorylation of S6K1 via the activation of phosphatases.
649

Area Efficient ADC for Low Frequency Application

Sami, Abdul Wahab January 2014 (has links)
Analog to digital converters (ADCs) are the fundamental building blocks in communication systems. The need to design ADCs, which are area and/or power efficient, has been common. Various ADC architectures, constrained by resolution capabilities, can be used for this purpose. The cyclic algorithmic architecture of ADC with moderate number of bits comes out to be probably best choice for the minimum area implementation. In this thesis a cyclic ADC is designed using CMOS 65 nm technology. The ADC high-level model is thoroughly explored and its functional blocks are modelled to attain the best possible performance. In particular, the nonlinearities which affect the cyclic/algorithmic converter are discussed. This ADC has been designed for built-in-self-testing (BiST) on a chip. It is only functional during the testing phase, so power dissipation is not a constraint while designing it. As it is supposed to be integrated as an extra circuitry on a chip, its area really matters. The ADC is designed as 10-bit fully differential switch-capacitor (SC) circuit using 65nm CMOS process with 1.2V power supply. A two stage Operational Transconductance Amplifier (OTA) is used in this design to provide sufficient voltage gain. The first stage is a telescopic OTA whereas the second is a common source amplifier. The bottom plate sampling is used to minimize the charge injection effect which is present in the switches.
650

Behaviour of Self Consolidating Steel Fiber Reinforced Concrete Beams Under Reversed Cyclic Loading

Aghniaey, Nima 07 February 2013 (has links)
Concrete is a very weak and brittle material in tension. It has been shown in previous researches that the addition of steel fibers to a concrete matrix can improve this behavior. The ability of fibers to control and redistribute stresses after cracking results in a number of improvements in the structural behaviour of concrete. A review of existing literature shows that the addition of steel fibers enhances concrete’s tensile resistance, crack control properties, ductility and damage tolerance. In beams, fibers can transform brittle shear response into a flexural response and promote ductility, thereby allowing for a full or partial replacement of traditional shear reinforcement. The enhanced shear capacity, ductility and damage tolerance of Steel Fiber Reinforced Concrete (SFRC) can also potentially be used to relax seismic detailing requirements in frames by partially replacing the required transverse reinforcement in the plastic hinge regions of RC beams. One of the drawbacks associated with SFRC is that the addition of steel fibers to a traditional concrete mix at high fiber contents can result in workability problems. The combined use of Self-Consolidating Concrete (SCC) and fibers can solve this problem and facilitate placement for a wider range of structural applications. Although several studies have been conducted on the behaviour of SFRC beams subjected to monotonic loading, there is limited research on the behaviour of SFRC beams under cyclic or reverse-cyclic loading. This thesis presents the results of an experimental and analytical study conducted on nine SFRC beam specimens tested under load reversals. The main objective of this research program was to investigate the effect of fibers on structural behaviour and to examine the ability of steel fibers to replace transverse reinforcement. The experimental and analytical results show that use of fibers results in several improvements in behaviour, including enhanced damage tolerance and post-peak ductility. The results also show that steel fibers can potentially be used to allow for a reduction of transverse reinforcement in beams, however further research is required.

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