• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 33
  • 6
  • 4
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 58
  • 58
  • 15
  • 9
  • 9
  • 9
  • 8
  • 7
  • 6
  • 6
  • 6
  • 5
  • 5
  • 5
  • 5
  • 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.
31

Functions of the cholinergic system in the morbidities associated with Alzheimer's disease and the further evaluation of tools for the molecular imaging of this system

Quinlivan, Mitchell. January 2007 (has links)
Thesis (Ph. D.)--University of Sydney, 2007. / Cotutelle thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Discipline of Pharmacology, Faculty of Medicine, University of Sydney and to the Doctoral School: Santé, Sciences et Technologies, University of Tours (France). Title from title screen (viewed Sept. 21, 2007). Includes bibliography. Also issued in print.
32

Frequency domain fluorescent molecular tomography and molecular probes for small animal imaging

Kujala, Naresh Gandhi, Yu, Ping, January 2009 (has links)
Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 26, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Dr. Ping Yu. Vita. Includes bibliographical references.
33

Optical and MR Molecular Imaging Probes and Peptide-based Cellular Delivery for RNA Detection in Living Cells

Nitin, Nitin. January 2005 (has links)
Thesis (Ph. D.)--Biomedical Engineering, Georgia Institute of Technology, 2006. / Dr. X. Hu, Committee Member ; Dr. Al Merrill, Committee Member ; Dr. Niren Murthy, Committee Member ; Dr. Gang Bao, Committee Chair ; Dr. Nicholas Hud, Committee Member. Includes bibliographical references.
34

Rapid and Cost-effective Virus Detection Methods using Molecular Sensors and Nano-devices

January 2016 (has links)
abstract: Accurate virus detection is important for diagnosis in a timely manner to facilitate rapid interventions and treatments. RNA viruses affect an extensive amount of the world’s population, particularly in tropical countries where emerging infectious agents often arise. Current diagnostic methods have three main problems: they are time consuming, typically not field-portable, and expensive. My research goal is to develop rapid, field-portable and cost sensitive diagnostic methods for RNA viruses. Herein, two different approaches to detect RNA viruses were proposed: Conjugated gold nanoparticles for detection of viral particles or virus-specific antibodies by monitoring changes in their optical properties, and Tentacle Probes coupled with qPCR for detection and differentiation of closely-related viral strains. The first approach was divided into two projects: the study and characterization of the gold nanoparticle-antibody system for detection of virus particles using dynamic light scattering (DLS) and UV-Vis spectrophotometry, and development of a detection method for antibodies using static light scattering (SLS) and antigen-conjugated gold nanoparticles. Bovine serum albumin (BSA) conjugated gold nanoparticles could successfully detect BSA-specific antibodies in vitro, and protein E from Dengue Virus serotype 2 conjugated gold nanoparticles could detect Dengue-specific antibodies, both in vitro and in serum samples. This method is more accurate than currently used detection methods such as dot blots. The second approach uses Tentacle Probes, which are modified molecular beacons, to detect with high specificity two different strains of Lymphocytic Choriomeningitis Virus (LCMV), Armstrong and Clone-13, which differ in only one nucleotide at the target sequence. We successfully designed and use Tentacle Probes for detection of both strains of LCMV, in vitro and in serum from infected mice. Moreover, detection of as little as 10% of Clone-13 strain was possible when diluted in 90% Armstrong strain. This approach enables the detection of different strains of virus even within a mixed quasispecies and may be important for improving intervention strategies for reducing disease. The detection methods provide rapid detection of viruses, including viral strains within mixed populations, and should enhance our ability in providing early responses to emerging infectious diseases due to RNA viruses including Zika or Dengue virus. / Dissertation/Thesis / Doctoral Dissertation Biochemistry 2016
35

Development of a novel in situ CPRG-based biosensor and bioprobe for monitoring coliform β-D-Galactosidase in water polluted by faecal matter

Wutor, Victor Collins January 2008 (has links)
The ultimate objective of this work was to develop a real-time method for detecting and monitoring β-D-galactosidase as a suitable indicator of the potential presence of total coliform bacteria in water environments. Preliminary comparison of the chromogenic substrate, chlorophenol red β-D-galactopyranoside and the fluorogenic substrate, MuGAL, revealed unreliable results with the fluorogenic technique due to interference from compounds commonly found in environmental water samples. Thus, the chromogenic assay was further explored. Hydrolysis of the chromogenic substrate chlorophenol red β-D-galactopyranoside by β-D-galactosidase to yield chlorophenol red was the basis of this assay. Fundamental studies with chlorophenol red β-Dgalactopyranoside showed that β-D-galactosidase occurs extracellularly and in low concentrations in the polluted water environment. A direct correlation between enzyme activity and an increase in environmental water sample volume, as well as enzyme activity with total coliform colony forming unit counts were observed. Spectrophotometric detection was achieved within a maximum period of 24 h with a limit of detection level of 1 colony forming unit 100 ml[superscript -1]. This enzyme also exhibited physical and kinetic properties different from those of the pure commercially available β-D-galactosidase. Cell permeabilisation was not required for releasing enzymes into the extracellular environment. PEG 20 000 offered the best option for concentrating β-D-galactosidase. The source of β-D-galactosidase in the polluted environmental water samples was confirmed as Escherichia coli through SDS-PAGE, tryptic mapping and MALDI-TOF, thus justifying the further use of this method for detecting and/or monitoring total coliforms. Several compounds and metal ions commonly found in environmental water samples (as well as those used in water treatment processes) did have an effect on β-D-galactosidase. All the divalent cations except Mg [superscript 2+], at the concentrations studied, inhibited the relative activity of β-D-galactosidase in both commercial β-D-galactosidase and environmental samples. Immobilisation of chlorophenol red β-D-galactopyranoside onto a solid support material for the development of a strip bioprobe was unsuccessful, even though the nylon support material yielded some positive results. A monthly (seasonal) variation in β-Dgalactosidase activity from the environmental water samples was observed, with the highest activity coinciding with the highest monthly temperatures. Electro-oxidative detection and/or monitoring of chlorophenol red was possible. Chlorophenol red detection was linear over a wide range of concentrations (0.001-0.01 μg ml[superscript -1]). Interference by chlorophenol red β-D-galactopyranoside in the reduction window affected analysis. A range of phthalocyanine metal complexes were studied in an attempt to reduce fouling and/or increase the sensitivity of the biosensor. The selected phthalocyanine metal complexes were generally sensitive to changes in pH with a reduction in sensitivity from acidic pH to alkaline pH. The tetrasulphonated phthalocyanine metal complex of copper was, however, more stable with a minimum change of sensitivity. The phthalocyanine metal complexes were generally stable to changes in temperature. While only two consecutive scans were possible with the unmodified glassy carbon electrode, 77 consecutive scans were performed successfully with the CuPc-modified glassy carbon electrode. Among the phthalocyanine metal complexes studied, the CuPc-modified glassy carbon electrode therefore provided excellent results for the development of a biosensor. The CuPc modified-glassy carbon electrode detected 1 colony forming unit 100 ml[superscript -1] in 15 minutes, while the plain unmodified glassy carbon electrode required 6 hours to detect the equivalent number of colony forming units. CoPc, ZnPc and CuTSPc required 2, 2.25 and 1.75 h, respectively, to detect the same numbers of colony forming units. The CuPcmodified glassy carbon electrode detected 40 colony forming units 100 ml[superscript -1] instantly. In general, a direct correlation between colony forming units and current generated in the sensor was observed (R2=0.92). A higher correlation coefficient of 0.99 for 0-30 coliform colony forming units 100 ml[superscript -1] was determined. Current was detected in some water samples which did not show any colony forming units on the media, probably due to the phenomenon of viable but non-culturable bacteria, which is the major disadvantage encountered in the use of media for detecting indicator microorganisms. This novel biosensor therefore presents a very robust and sensitive technique for the detection and/or monitoring of coliform bacterial activity in water.
36

Développement de sondes moléculaires appliquées à l’étude de la biosynthèse des flavonoïdes / Molecular probes development for Flavonoid biosynthesis studying

Carrié, Hélène 20 December 2013 (has links)
Les flavonoïdes sont des substances naturelles connues pour leurs propriétés anti-inflammatoires, anti-cancéreuses ou anti-virales chez l'homme. Chez les végétaux, ils participent notamment à leur protection vis-à-vis d'organismes pathogènes. La voie de biosynthèse des flavonoïdes est l'une des plus étudiées chez les plantes et notamment chez la vigne : Vitis vinifera. Cependant, la ou les enzymes impliquées dans les dernières étapes de biosynthèse conduisant aux anthocyanes et aux proanthocyanidines restent, à ce jour, peu ou pas connues. L’étude que nous proposons a pour but de concevoir des sondes moléculaires d’affinité susceptibles d’interagir avec une ou plusieurs enzymes impliquées dans ces dernières étapes de biosynthèse. Ces sondes, basées sur la technologie émergeante de protéomique chimique : « Activity- and affininity Based Protein Profiling » (ABPP), ont été validées à l’aide d’une enzyme modèle : la leucoanthocyanidine dioxygénase (LDOX). Elles ont ensuite été appliquées à des extraits complexes de protéines issus de Vitis vinifera. / Flavonoids are natural substances known for their anti-inflammatory, anti-cancerous and anti-virals properties in humans. In plants, they are one of the molecules responsible for fighting pathogens. The flavonoid biosynthesis pathway as been greatly studied in plants, especially in that of the grapevine: Vitis vinifera. However, detailed studies of the exact function of the enzymes involved in the last steps of the biosynthesis of anthocyanins and proanthocyanidins remains largely lacking.The study that we propose is to synthesize molecular probes designed to specifically interact with enzymes involved in the last stages of flavonoids biosynthesis. Our probes, based on the emerging chemical proteomic technology, activity- and affinity based protein profiling (ABPP), were validated with a model enzyme: leucoanthocyanidin dioxygenase (LDOX). After which, they were used with complex protein mixtures from Vitis vinifera.
37

Applications of Stimulated Raman Scattering Microscopy: from Label-free to Molecular Probes

Miao, Yupeng January 2021 (has links)
The newly emerging Stimulated Raman Scattering (SRS) Microscopy has been proved to be a powerful tool in biomedical research. This advanced imaging platform offers high spatiotemporal resolution and chemical specificity, which greatly empowers the label-free biomedical imaging and small molecule metabolite tracing. Throughout the research introduced in this thesis, we focus on the exploration of more applications of SRS microscopy beyond aforementioned. Particularly, this new expedition involves more chemistry and answered two major questions: what SRS can do for chemistry and what chemistry can do for SRS. Chapter 1 introduces the basics of SRS microscopy, such as the physical fundamentals and start-of-art instrumentations. Besides, this chapter discusses the design principles of vibrational reporters through a chemistry view. Chapter 2 introduces one of the major progresses of SRS microscopy beyond biomedical study. We use SRS microscopy to study the ion transportation and concentration polarization phenomena in lithium metal batteries (LMBs), with a strong focus in solid-state polymer electrolyte. A self-induced phase separation process over lithium metal electrode is observed and correlated with local lithium ion concentrations, which inspires a protection mechanism for durable LMB design. Chapter 3 discusses the use of SRS microscopy for in-vivo drug tracing in mammalian cells. A novel alkyne tag is incorporated into bio-engineered natural depsi-peptides and serves as Raman reporter. The mode-of-action of the labeled drug is visualized with SRS microscopy. Chapter 4 heavily focuses on the development of synthetic molecular probes for super-multiplexed optical imaging. We systematically synthesize a library of molecular probes based on 9-cyanopyronin, and their Raman features are characterized to build a model that correlates photophysical properties with structures. The Raman shifts of probes can be tuned with high precision. The multiplexing capability of the new library is demonstrated in labeling fixed and living cell samples.
38

<strong>THE DEVELOPMENT OF A MOLECULAR PROBE CAPABLE OF IDENTIFYING NATURAL PRODUCTS CONTAINING FURAN MOIETIES</strong>

Alyssa September Eggly (16640802) 08 August 2023 (has links)
<p>Natural products, along with natural product derivatives, are known to be at the root of the development of many pharmaceuticals, oftentimes showing unique bioactivity against interesting targets. Specifically, natural products containing furans show activity against a variety of diseases including fungal infections, and cancers. It is hypothesized that unknown natural products containing furans could show more potent or other biological activities. However, it is challenging to discover and isolate these small molecules from cell supernatant. The work described herein showcases the development of a molecular probe that can covalently attach to furan moieties via a [4 + 2] Diels-Alder cycloaddition, making them easily identifiable on liquid chromatography mass spectroscopy (LC-MS). The molecular probe, which undergoes this reaction with a variety of furans, was designed with both a UV-tag and a mass tag to enable easy identification. The probe has been tested with a variety of purified furans, including natural products, methylenomycin furan (MMF) hormones, and MMF derivatives. Moreover, work has begun to test the molecular probe in cell supernatants. </p>
39

Probing the molecular recognition of a DNA-RNA hybrid duplex

Wheelhouse, Richard T., Garbett, N.C., Buurma, N.J., Chaires, J.B. 2010 March 1929 (has links)
Yes / Curiouser and curiouser! A biarylpyrimidine ligand (see picture: N blue, H cyan, S yellow) shows a marked structure and sequence selectivity for the poly(dA)⋅poly(rU) hybrid duplex. An intercalative binding site was discovered where the ligand occupies a surprising ten base pairs. A strong correlation between hybrid duplex and DNA triplex binding indicates new directions for ligand design.
40

Development of advanced cross conjugated systems and applications in ratiometric sensing: altering the electronic properties of cruciforms and poly(para-phenyleneethynylene)s to elicit differing reactivity and response

Davey, Evan Andrew 13 May 2012 (has links)
This research serves as a meticulous examination into cross-conjugated materials and how alterations of the frontier molecular orbitals can be utilized for applications in "chemical tongue" organic sensing devices. With conjugated materials being used in the development of new sensory devices for detection of metals, bacteria, and chemical warfare agents, the field of organic sensing is growing faster than ever. The purpose of this dissertation is to provide a precedence for the synthesis of new cross-conjugated compounds and outline potential applications of these materials as chemical sensors and molecular probes.

Page generated in 0.32 seconds