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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.
61

Experimental Investigation and Mathematical Modelling Of Mechanical Properties Of Shooks And Finger Jointed Timber

How, Seok Sean January 2015 (has links)
The issue on variability of mechanical properties within wood has found to be increasingly prominent in recent years. On the other hand, it is known that uniformity of wood properties is essential in quality control in the timber manufacturing such as manufacturing of Glued Laminated (Glulam) timber. The AS/NZS 1328 P2 specified that the overall mechanical properties of Glulam timber can be estimated based on the MOE of the finger jointed laminates and the arrangement of the corresponding laminates. In relating to the above standard, optimisation in the arrangement of shooks’ location along the finger jointed laminate will enable determination of the overall MOE of laminates, as well as optimise the utilisation of feedstocks. In this study, a deterministic model was developed in relating the local shook’s modulus of elasticity (MOE) with the overall MOE of the corresponding finger jointed timber based on the principle of the Moment of Curvature. The projected overall MOE is calculated as a function of lengths and MOEs of individual shooks in the finger joint timber. The effect of shooks’ location can also be determined from the model. Numerical derivation of the model was addressed and the analyses of the relationships between the local shook MOEs, the overall MOE, and bending strength (MOR) were assessed. Experimental results showed that the model can effectively predicts the overall MOE, particularly on shook combinations with random and large standard deviations in shook MOEs. The errors of the predictive model were ranged from -8.17% to +0.81%. Results from the assessment on the relationships between the overall MOE and bending MOR indicated that wood failure in the combinations of small standard deviations shook MOEs was most likely to occur at the weakest point, however, wood failures may not necessarily occur in the shook with the lowest MOE in the asymmetrical MOE arrangements. This also applies to the finger jointed timber with combinations of shooks with large standard deviations for local MOEs. In addition, the relationship between dynamic MOE of shooks and the static bending overall MOE were assessed. A linear regression has been suggested for the adjusted shooks dynamic MOE at 36 mm thickness. The predictability of the model could further improve when the shook MOEs were sorted according to sawing pattern and the proposed model for quarter sawn is suggested. Lastly, economic analysis was performed based on the models available in literature and the developed model in this study. Models reported in the literature including the arithmetic mean model and model based on the shook’s minimum MOE. The results from economic analysis showed that the study’s model was most cost effective in predicting the cost of shooks based on the predicted overall finger jointed MOE using the model as compare to the arithmetic mean and the minimum shook MOE method. In conclusion, the proposed model has demonstrated to be unique, simple, effective and robust in predictive applications.
62

Highly Active Zinc Finger Nucleases by Extended Modular Assembly

Bhakta, Mital Subhash January 2012 (has links)
C2H2-zinc fingers (ZFs) are commonly found in transcription factors that code for nearly 3% of gene products in the human genome. ZF proteins are commonly involved in gene regulation during development, cell differentiation, and tumor suppression. Each "finger" is a domain composed of approximately 30 amino acids. Since the discovery of these domains over 25 years ago, several groups have contributed to the structural and biochemical knowledge to understand their DNA-binding properties. Taking advantage of the simplicity of manipulating the DNA-binding potential of a ZF, the technology has now evolved to make sequence-specific Zinc Finger Nucleases (ZFNs), Artificial Transcription Factors (ATFs), Zinc Finger Recombinases, and DNA detection tools. ZFPs have been used for various applications, ranging from regulating genes by ZF-ATFs to manipulating genomes in diverse organisms. ZFNs have remarkably revolutionized the field of genome engineering. ZFN-modified T-cells have now advanced into human clinical trials for cell-based therapies as a treatment against HIV. Despite the advances in the ZFN technology, one of the challenges in the field is obtaining effective ZFNs using publicly available tools. The traditional method of synthesizing custom ZF arrays was using modular assembly (MA). In this method, preselected ZFs from publicly available one-finger archives can be assembled modularly to make long arrays. MA of ZFNs provides a rapid method to create proteins that can recognize a broad spectrum of DNA sequences. However, three- and four-finger arrays often fail to produce active nucleases. The low success rate of MA ZF arrays was attributed to the fact that they suffer from finger-finger incompatibility referred to as context-dependent effects. However, we hypothesized that the low affinity of MA arrays was the limiting factor. The work presented in this dissertation describes our efforts at addressing these fundamental methodological challenges. We developed the Extended Modular Assembly method that overcomes the limitations of both the previous Modular Assembly. We performed a systematic investigation of number and composition of modules on ZFN activity and analyzed ZFN specificity both in vitro and in vivo. Our current experiments apply the ZFNs produced by our method to study the role of genetic variation in human disease.
63

A Comparison of Non-Destructive Techniques to Discover Defect Finger Joints in Furniture

Björnberg, Jonatan January 2014 (has links)
The aim of this study has been to investigate the possibilities to identify lack of glue in finger joints by checking different non-destructive techniques. Specifically, this study puts emphasis on finding a method suitable for an automated and fast industry production line of home furnishing products. The methods investigated are of three main varieties: Sound/vibration Thermography Tomography The most promising method was the high-power ultrasound thermography. This method is fast and reliable, but more research is needed. It is necessary to find out if the thermography waves can penetrate deep enough. Another possible method is computed tomography. This method can take a lot of time, but the speed of scanning depends on the accuracy demanded. / Uppgiften har varit att granska möjligheterna att identifiera bristfälliga trälimningar eller helt avsaknad av lim i fingerskarvar med hjälp av olika metoder som inte förstör materialet, NDT (non-destructive testing). Undersökningen syftar speciellt till att finna en metod som är anpassad till ett effektivt produktionsflöde i industrin. Det måste där med vara en metod som med stor snabbhet kan hitta eventuella fel på produkterna. De metoder som mer omfattande har granskats är ljud/vibration, termografi och tomografi. Den metod som visat sig mest lovande är high-power ultrasound thermography. Tester måste dock utföras för att säkerställa att metoden är passande för ändamålet. Framför allt om de termografiska vågorna tränger in tillräckligt djupt. En annan möjlighet är datortomografi. Denna metod kan vara tidskrävande, men skanningshastigheten beror på hur noggrant mätresultat som erfordras. Här finns också en säkerhetsaspekt som måste beaktas, eftersom röntgenstrålar används.
64

Characterisation of endogenous KRAB zinc finger proteins

Crawford, Catherine January 2009 (has links)
The Krüppel-associated box (KRAB) zinc finger protein (ZFP) genes comprise one of the largest gene families in the mammalian genome, encoding transcription factors with an N-terminal KRAB domain and C-terminal zinc fingers. The KRAB domain interacts with a co-repressor protein, KAP-1, which can recruit various factors causing transcriptional repression of genes to which KRAB ZFPs bind. Little is currently known about the gene targets of the ~400 human and mouse KRAB ZFPs. Many KRAB ZFPs interact with factors other than KAP-1. To identify proteins that may interact with one particular KRAB ZFP, Zfp647, I previously carried out a yeast two-hybrid screen using the full-length Zfp647 sequence and a mouse embryonic cDNA library. I have now tested the interactions from this screen for their specificity for Zfp647. I show that Zfp647 can interact with itself and at least 20 other KRAB ZFPs through their zinc finger domains, and have confirmed the Zfp647 self-interaction by in vitro co-immunoprecipitation. In my yeast two-hybrid screen, Zfp647 bound to KAP-1 as well as another related protein, ARD1/Trim23. Zfp647 also interacts with proteins that function in ubiquitylation. I have found evidence to suggest that Zfp647 may also interact with proteins encoding jumonji domains both by yeast two-hybrid assay and by co-immunoprecipitation from NIH/3T3 cell extracts. We have previously found that Zfp647 localises to non-heterochromatic nuclear foci in differentiated ES cells, which also contain KAP-1 and HP1, and which lie adjacent to PML nuclear bodies in a high proportion of cells. I have found that these foci are also visible in pMEFs, but not NIH/3T3 tissue culture cells. Immunofluorescence studies with antibodies against proteins from the yeast twohybrid screen have not shown any significant co-localisation with Zfp647. KAP-1 is sumoylated ex vivo, as are two human KRAB ZFPs. Because Zfp647 lies adjacent to PML nuclear bodies and can associate with proteins involved in posttranslational modification, I tested whether Zfp647 is also modified. I characterised a sheep _-Zfp647 antibody previously created in the lab and have shown that it detects Zfp647 by western blot, but not by immunofluorescence. I show that treatment of NIH/3T3 cells with NEM, which prevents the removal of protein modifications, leads to the appearance of higher molecular weight forms of Zfp647. Modification of Zfp647 is not dependent on KAP-1, which is known to function as a SUMO E3 ligase. Attempts to classify the modification as either ubiquitin, SUMO or NEDD8 have suggested that Zfp647 may be mono-ubquitylated. The larger modified forms of Zfp647 are present in both NIH/3T3 and ES cells. Interestingly, I found that the modification profile of the protein changes over the course of ES cell differentiation, during which time Zfp647 relocalises to punctate nuclear foci; thus Zfp647 modification may be involved in this process.
65

NMR Study of Structure and Orientation of S4-S5 Linker Peptides from Shaw Related Potassium Ion Channels in Micelles and Binding of ZNF29R Protein to HIV RREIIBTR RNA

Qu, Xiaoguang 28 May 2009 (has links)
Potassium ion channels play a key role in the generation and propagation of action potentials. The S4-S5 linker peptide (L45) is believed to be responsible for the anesthetic/alcohol response of voltage-gated K+ channels. We investigated this region to define the structural basis of 1-alkanol binding site in dShaw2 K+ channel. L45 peptides derived from dShaw2 and hKv3.4 K+ channel, which, if part of the complete channel, demonstrate different sensitivity to 1-alcohols. Specifically, dShaw2 is alcohol sensitive and hKv3.4 is alcohol resistant. Structural analysis of L45 with NMR and CD suggested a direct correlation between alpha-helicity and the inhibition of dShaw2 channel by 1-butanol. We used CD and NMR to determine the structure of L45 peptides in micelles and vesicles. We measured spin-lattice relaxation time (T1) and determined the location and surface accessibility of L45 in micelles. These experiments confirm that L45 of dShaw2 adopts an α-helical conformation, partially buried in the membrane and parallel to the surface. The binding and accumulation of rev proteins to an internal loop of RRE (rev responsive element) of unspliced mRNA precursors is a key step of propagation of human immunodeficiency (HIV) virus. Molecules that interfere with this process can be expected to show anti-HIV activity. Our work is based on an assumption that zinc fingers could compete with rev proteins, therefore impeding the life cycle of HIV and stopping its infection. We studied the influence of different cations, anions, and the concentration of salts and osmolytes on the binding affinity with Polyacrylamide Gel Electrophoresis (PAGE) and Isothermal Titration Calorimetry (ITC). We conclude that the types of anions and/or cations and their concentrations affect the enthalpy and entropy of the binding interacitons. Using a gel assay, we confirm that there are three products in RNA-Protein reaction, and both EDTA and salts (and their concentrations) in the gel or samples interfere with RNA-protein complex mobility.
66

Genetic dissection of nitric oxide signalling network in plant defence response

Yin, Minghui January 2014 (has links)
Following pathogen recognition, nitric oxide (NO) is rapidly produced in plants, this small molecule has emerged as a key signal in plant defence responses. S-nitrosylation is the major route of NO signal transduction in plants, a redox-based modification by addition of an NO moiety on cysteine thiol to form an S-nitrosothiol (SNO). S-nitrosoglutathione reductase (GSNOR) regulates cellular levels of S-nitrosylation and displays a key role in regulating the plant defence response. In this context, NO is important to orchestrate both defence gene expression and the hypersensitive response (HR) during attempted microbial infection. However, how the plant immune system recognizes NO and how NO level could elicit plant defence responses are poorly understood. The Arabidopsis thaliana (Arabidopsis) mutant NO overproducing 1 (nox1) was employed to characterize how NO level elicits defence dynamics. In response to microbial infection, resistance (R) gene-mediated defence and basal resistance were found to be compromised in the nox1 mutant relative to wild type Col-0 plants. Interestingly, nox1 mutant exhibit similar levels of HR and pathogen susceptibility to the GSNOR loss-of-function mutant atgsnor1-3. This phenomenon suggests that NO might regulate defence responses via GSNOR-mediated S-nitrosylation. Therefore, the nox1 atgsnor1-3 double mutant was generated and characterized to clarify this hypothesis. Accelerated HR and increased pathogen susceptibility are shown in the double mutant, which implies that increased NO mediated by nox1 and elevated SNOs resulting from atgsnor1-3, are additive with respect to the plant defence response. To identify genes responsible for NO perception, forward genetic screens were developed to identify Arabidopsis mutants with abnormal NO recognition. NO marker genes for genetic screens were identified from both lab and open source microarray data. Two genes, At3g28740 and At1g76600 were selected and experimentally confirmed to be strongly induced by NO. Transgenic Arabidopsis plants were generated carrying a NO reporter cassette, which consist of a luciferase reporter gene (LUC) driven by the promoter of NO marker gene. This forward genetic approach might be a powerful tool to identify genes integral to NO signal transduction. Three C2H2 zinc finger transcription factors (ZnTFs) ZAT7, ZAT8 and ZAT12 were identified as being rapidly and strongly induced by NO donors, which could be modulators of redox/NO-dependent signalling pathway. T-DNA insertion mutants within these ZnTFs have been identified. Basal resistance against Pseudomonas syringae pv tomato (Pst) DC3000 is compromised in all single knockout lines. Therefore, the full characterisation of defence phenotype of these mutants would be necessary to explore the role of these TFs in the plant defence. Furthermore, zat8 mutant is more sensitive to nitrosative stress when compared to wild type Col-0. This suggests that ZAT8 may be involved in protecting plants against nitrosative stress. However, the molecular mechanisms that underpin this function remain to be determined. In conclusion, NO and SNOs might regulate plant disease resistance via distinct pathways. Our work has also established NO-reporter lines to identify genes responsible for NO perception. In addition, three NO-induced ZnTFs have been identified that participate in regulation of basal resistance, which might unveil aspects of NO signalling related to the regulation of transcription.
67

Daktyloskopie - historie, současnost a budoucnost / Fingerprinting - Past, Present and Future

Semera, Lukáš January 2015 (has links)
FINGERPRINTING - PAST, PRESENT AND FUTURE The objective of this thesis is to present the forensic fingerprinting as a scientific method which, although in comparison with other forensic sciences being one of the oldest, is not out-dated at all, quite to the contrary - it presents an ever-changing and continuously developing field of science. The objective is approached through three distinctive and yet intertwined chapters corresponding with the title of the thesis - past, present and future of the fingerprinting. They are also designed, at least in part, to capture this constant forward motion. Accordingly, the first chapter aims to describe briefly scientific roots of the method, the way it drew in its beginnings from various scientific discoveries, inspired by the rise of Darwinism. Particular emphasis is put on the description of the formulation and empirical confirmation of three physiological laws of fingerprinting that even today serve as its grounds. The second chapter deals with and tries to describe the current state of knowledge and particular methods used in detection, development and preservation of fingerprints, especially latent ones. To do this it seems to be necessary to describe briefly the anatomy and physiology of friction ridge skin, as it enables to fully comprehend the way in...
68

Vliv polohy paže na testování síly flexorů prstů u sportovních lezců / Effect of arm position on finger flexor strength measurement in sport climbers

Kodejška, Jan January 2014 (has links)
Title: Effect of arm position on finger flexor strength in sport climbers Objectives: The main purpose of this study was to assess the effect of arm position on finger flexor strength in sport climbers. Methods: Twenty-one women (age 24,5 ± 2,7 years, body weight 59,5 ± 8,3 kg, height 166,4 ± 6 cm) and twenty-five men (age 26,9 ± 5,3 years, body weight 71,7 ± 7,7 kg, height 177,2 ± 5,3 cm) volunteered to be a part of the study. The RP performance varied from the 3rd to 10th degree UIAA (Union International des Assocoation d'Alpinisme) scale. A specially manufactured tool was used to measure the finger flexor force with different positions of an arm. During the study, measurements were taken as the arm was adjusted into four different positions: Handgrip (0ř shoulder and elbow in full extension), Flexion90 (90ř shoulder flexion and external rotation of 45ř and the elbow in 90ř flexion supported by a board), Flexion130 (the arm 130ř abduction and elbow flexion 50ř) and Flexion180 (180ř shoulder flexion and elbow in full extension). The open grip was used for all positions, except for the Handgrip position where the thumb was in opposition. Results: The highest relation between the relative strength and RP climbing performance was found in the Flexion130 (r = 0,81) in women and in Flexion180 (r =...
69

Efekt dvou typů aktivního odpočinku na opakovaný izometrický výkon flexorů prstů / Effect of two active recovery methods on repeated bouts of finger flexor isometric performance

Psohlavec, Lukáš January 2016 (has links)
Title: Effect of two active recovery methods on repeated bout of finger flexors isometric performance. Goals: Compare two methods of active recovery - global and local, during repeated isometric performance and learn the difference between active and passive recovery. Method: Ten recreational athletes in average age 30,4 ± 5,9 years performed in a random cross-over desing 3 sessions with 3 repeated isometric intermittent contraction. The effect of active global recovery, active local recovery and passive recovery between repetions was monitored. Results: More effective type of recovery was active recovery. There was no difference between both active recovery methods. Performed decrease in active global recovery was activleast effective method of recovery was passive recovery. Decrease in the time in active global recovery was 21,7s (29,77%) and in active local recovery 20,8s (30,1%). The least effective was passive recovery. There was decrease 24,6s (35,34%). Key words: recovery, active recovery, local recovery, finger flexors, interrmitent, isometric contraction.
70

Fadiga em emendas dentadas em madeira laminada colada / not available

Macêdo, Alcebíades Negrão 28 June 2000 (has links)
O objetivo deste trabalho é o estudo da resistência e rigidez das emendas dentadas à fadiga na tração com as finalidades de propor uma metodologia de ensaio e estimar um coeficiente redução da resistência à fadiga na tração das emendas dentadas em relação a madeira maciça, contribuindo para a caracterização destas ligações. Foram utilizadas duas espécies de madeira, Pinus caribea hondurensis e Eucalyptus grandis, e dois tipos de adesivos sendo um industrial à base de fenol-resorcinol e um poliuretano à base de resina de mamona desenvolvido no Instituto de Química de São Carlos. Foram realizados ensaios cíclicos para três níveis de freqüência (1 Hz, 5 Hz e 9 Hz) e três níveis de tensão (90%, 75% e 60% da resistência) a uma relação R = 0,1. Com base nos resultados foram propostos coeficientes de redução de resistência à fadiga da emenda dentada em relação à madeira maciça e verificar que não há variação significativa da rigidez em função do número de ciclos. / The aims of this work is the study of the fatigue strength and stiffness of the finger joints in tension, in order to propose an experimental methodology and to determine a strength reduction coefficient, in relation to solid wood, contributing to the characterization of these joints. Two wood species, Pinus caribea hondurensis and Eucalyptus grandis, and two adhesives types were used, being an industrial one phenol-resorcinol based and a poliuretane castor oil resin based, developed at the lnstitute of Chemistry of São Carlos. Cyclical tests were accomplished in three frequency levels (1 Hz, 5 Hz and 9 Hz) and three tension levels (90%, 75% and 60% of the strength) to a relationship R = 0,1. Based on the results, it were proposed strength reduction coefficients in relation to solid wood, for finger joints under fatigue in tension, and to concluded that there is no significant variation in stiffness with the cycle numbers.

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