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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.
481

Tabako gaminių ženklinimo politikos analizė / Tobacco labeling policy analysis

Dacytė, Asta 03 June 2014 (has links)
Magistro baigiamajame darbe išanalizuota tabako gaminių ženklinimo politika, jos pokyčių svarba ir įtaka tabako vartojimo paplitimo mažinimui. Pirmoje dalyje išskiriama tabako daroma žala sveikatai ir aptariama PSO strategija „Sveikata visiems XXI a.“, Tabako kontrolės pagrindų konvencija bei Tabako gaminių direktyva. Antroje dalyje nagrinėjama tabako gaminių kontrolės ir įgyvendinimo politika Lietuvoje. Šioje dalyje pabrėžiama tabako kontrolės politikos sistema, išskiriant svarbiausias vyriausybės programas ir įstatymus, kontrabandos prevencijos ir akcizų didinimo svarbą šalies ekonomikai bei sveikatos sektoriui. Trečioje dalyje kalbama apie tabako gaminių ženklinimo svarbą, aptariami ženklinimo būdai Lietuvoje ir kitose šalyse, išsakoma gamintojų pozicija. Ketvirtoje dalyje pateikiama kokybinio tyrimo metodika, analizė ir apibendrinimas. Darbas užbaigiamas pateikiant išvadas ir rekomendacijas, kaip būtų galima tobulinti tabako gaminių ženklinimo politiką Lietuvoje. / Master's thesis analyzed tobacco labeling policy, the importance of it’s changes and the impact of reducing the prevalence of tobacco use. The first part identifies the tobaccorelated harm to health and discusses the WHO strategy "Health for all XXIst century ", Framework Convention on Tobacco Control and Tobacco Products Directive. The second part analyzed tobacco control policy implementation in Lithuania. It highlights tobacco control policy framework, highlighting the most important government programs and laws, smuggling prevention and excise increase importance for the national economy and the health sector. The third part presents importance of the labeling of tobacco products, discusses methods of labeling in Lithuania and other countries, conveys producers’ position. The fourth part is based on analysis and generalization. The thesis is completed by the findings and recommendations on how to improve the labeling of tobacco policy in Lithuania.
482

Development and Applications of Chemical Labeling Protocols for Protein-Ligand Binding Analysis Using Bottom-Up Proteomics

Xu, Ying January 2011 (has links)
<p>Proteins fold into well-defined three-dimensional structures to carry out their biological functions which involve non-covalent interactions with other cellular molecules. Knowledge about the thermodynamic properties of proteins and protein-ligand complexes is essential for answering fundamental biological questions and drug or biomarker discovery. Recently, chemical labeling strategies have been combined with mass spectrometry methods to generate thermodynamic information about protein folding and ligand binding interactions. The work in this thesis is focused on the development and application of two such chemical labeling protocols coupled with mass spectrometry including one termed, SUPREX (stability of unpurified proteins from rates of H/D exchange), and one termed SPROX (stability of proteins from rates of oxidation). The work described in this thesis is divided into two parts. The first part involves the application of SUPREX to the thermodynamic analysis of a protein folding chaperone, Hsp33, and its interaction with unfolded protein substrates. The second part involves the development of a new chemical labeling protocol that can be used to make protein folding and ligand binding measurements on the proteomic scale. </p><p>In the first part of this work, the SUPREX technique was used to study the binding interaction between the molecular chaperone Hsp33 and four different unfolded protein substrates including citrate synthase, lactate dehydrogenase, malate dehydrogenase, and aldolase. The results of the studies, which were performed at the intact protein level, suggest that the cooperativity of the Hsp33 folding/unfolding reaction increases upon binding with denatured protein substrates. This is consistent with the burial of significant hydrophobic surface area in Hsp33 when it interacts with its substrate proteins. The SUPREX derived Kd-values for Hsp33 complexes with four different substrates were also found to be all within a range of 3-300 nM. The interaction between Hsp33 and one of its substrates, citrate synthase (CS), was characterized at a higher structural resolution by using the SUPREX technique in combination with a protease digestion protocol. Using this protocol, the thermodynamic properties for both Hsp33 and CS were evaluated at different stages of binding, including reduced Hsp33 (inactive form), oxidized Hsp33 (active form), followed by native CS and finally of Hsp33ox -CS complexes before and after reduction with DTT. The results suggest that Hsp33 binds unfolded proteins that still have a significant amount of residual higher- order structure. Structural rearrangements of the substrate protein appear to occur upon reduction of the Hsp33-substrate complexes, which may facilitate the transfer of the substrate protein to other protein folding chaperone systems. </p><p>In the second part of this dissertation, a mass spectrometry-based covalent labeling protocol, which relies on the amidination rate of globally protected protein amine groups, was designed and applied to the thermodynamic analysis of several eight protein samples including: six purified proteins (ubiquitin, BCAII, RNaseA, 4OT, and lysozyme with, and without GlcNAc), a five-protein mixture comprised of ubiquitin, BCAII, RNaseA, Cytochome C, and lysozyme, and a yeast cell lysate. The results demonstrate that in ideal cases the folding free energies of proteins and the dissociation constants of protein-ligand complexes can be accurately evaluated using the protocol. Also demonstrated is the new method's compatibility with three different mass spectrometry-based readouts including an intact protein readout using MALDI, a gel-based proteomics readout using MALDI, and an LC-MS-based proteomics readout using isobaric mass tags. The results of the cell lysate sample analysis highlight the complementarity of the labeling protocol to other chemical modification strategies that have been recently developed to make thermodynamic measurements of protein folding and stability on the proteomic scale.</p> / Dissertation
483

Miljömärkningar och medvetenhet : En studie om unga vuxnas medvetenhet kring miljömärkningar / Environmental labels and awareness : A study on awareness of young adults on environmental labels

Mester Pirttijärvi, Josefin January 2014 (has links)
Dagens samhälle är präglat av materialism och dagens konsumtionsmönster är ohållbara ur miljömässig synpunkt. Konsumtionen skapar därmed miljöproblem och ett viktigt styrmedel för att göra den mer hållbar är miljömärkning. Miljömärkta produkter produceras på ett miljöansvarigt sätt utan kemiska bekämpningsmedel och gödsel som är skadliga för både människa och miljö. Syftet med denna studie var att undersöka den nuvarande medvetenheten kring miljömärkningar hos unga vuxna på Möckelngymnasiet. Metoden för studien var enkätutdelning till skolklasser som går sista året på gymnasiet. Utfallet av undersökningen visar att medvetenheten kring miljömärkningar är stor hos respondenterna och att respondenterna känner igen många av miljömärkningarna. Allmän kunskap om människans miljöpåverkan och om konsumentansvar visas i de flesta fallen vara knutna till val av miljömärkta produkter. En anledning till att köpa miljömärkta produkter är ansvarskänsla, vilket tyder på ekologiskt medborgarskap hos respondenterna. En anledning till att inte köpa miljömärkta produkter är för högt pris, vilket visar att det kan vara kontextuella faktorer som gör att vissa respondenter inte köper miljömärkta produkter. / Today’s society is characterized by materialism and today’s consumption patterns are unsustainable from an environmental point of view. The consumption is thus creating environmental problems and an important instrument to make it more sustainable is environmental labeling. Environmental labeled products are being produced in an environmental responsible manner without chemical pesticides or manure that both are harmful for humans and the environment. The purpose of this study was to examine the current state of awareness on environmental labels of young adults in a high school called Möckelngymnasiet. The method of the study was to do a survey research in classes with final year high school students. The outcome of the survey shows that the awareness on environmental labels is high among the respondents and that the respondents recognize many of the environmental labels. General knowledge on human’s environmental impact and on responsibility of consumers is shown to in most cases be linked to buying environmental labeled products. One reason to buy environmental labeled products is a sense of responsibility, which indicates on ecological citizenship among the respondents. One reason to not buy environmental labeled products is too high price, which shows that contextual factors can lead to that some respondents not buying environmental labeled products.
484

Imaging Microvascular Changes Associated with Neurological Diseases

Chugh, Brige 21 August 2012 (has links)
Microvascular lesions of the brain are observed in numerous pathological conditions including Alzheimer's disease (AD). Regional patterns of microvascular abnormality can be characterized using current neuroimaging technologies. When applied to mouse models of human disease, these technologies reveal cerebral vascular patterns and help uncover genotype-to-phenotype relationships. This thesis focuses on the development and testing of techniques for measuring two perfusion-related metrics in mouse brain regions, namely, cerebral blood volume (CBV) and cerebral blood flow (CBF) using micro-computed tomography (micro-CT) and arterial spin labeling (ASL), respectively. The main developments for measurement of CBV have included: refinements to micro-CT specimen preparation; registration of micro-CT images to an MRI anatomical brain atlas; and masking of major vessels to calculate small-vessel CBV (sv-CBV). The development of this micro-CT technique provided reference values of CBV over neuroanatomical brain regions in wildtype mice. A separate study was conducted to assess regional sv-CBV in a mouse model of AD; this study was motivated by the prevalence of microvascular lesions in patients who suffer from AD. Significant regional differences in sv-CBV were found between AD-afflicted mice and controls. The main developments for measurement of CBF have included: design and implementation of accurate ASL slice positioning and optimization of inversion efficiency parameters. The development of this ASL technique provided reference values of CBF over neuroanatomical brain regions in wildtype mice. These techniques for measuring CBV and CBF over mouse brain regions could lead to improved characterization of vascularity in models of neurological diseases.
485

Imaging Microvascular Changes Associated with Neurological Diseases

Chugh, Brige 21 August 2012 (has links)
Microvascular lesions of the brain are observed in numerous pathological conditions including Alzheimer's disease (AD). Regional patterns of microvascular abnormality can be characterized using current neuroimaging technologies. When applied to mouse models of human disease, these technologies reveal cerebral vascular patterns and help uncover genotype-to-phenotype relationships. This thesis focuses on the development and testing of techniques for measuring two perfusion-related metrics in mouse brain regions, namely, cerebral blood volume (CBV) and cerebral blood flow (CBF) using micro-computed tomography (micro-CT) and arterial spin labeling (ASL), respectively. The main developments for measurement of CBV have included: refinements to micro-CT specimen preparation; registration of micro-CT images to an MRI anatomical brain atlas; and masking of major vessels to calculate small-vessel CBV (sv-CBV). The development of this micro-CT technique provided reference values of CBV over neuroanatomical brain regions in wildtype mice. A separate study was conducted to assess regional sv-CBV in a mouse model of AD; this study was motivated by the prevalence of microvascular lesions in patients who suffer from AD. Significant regional differences in sv-CBV were found between AD-afflicted mice and controls. The main developments for measurement of CBF have included: design and implementation of accurate ASL slice positioning and optimization of inversion efficiency parameters. The development of this ASL technique provided reference values of CBF over neuroanatomical brain regions in wildtype mice. These techniques for measuring CBV and CBF over mouse brain regions could lead to improved characterization of vascularity in models of neurological diseases.
486

Image Retrieval Based On Region Classification

Ozcanli-ozbay, Ozge Can 01 June 2004 (has links) (PDF)
In this thesis, a Content Based Image Retrieval (CBIR) system to query the objects in an image database is proposed. Images are represented as collections of regions after being segmented with Normalized Cuts algorithm. MPEG-7 content descriptors are used to encode regions in a 239-dimensional feature space. User of the proposed CBIR system decides which objects to query and labels exemplar regions to train the system using a graphical interface. Fuzzy ARTMAP algorithm is used to learn the mapping between feature vectors and binary coded class identification numbers. Preliminary recognition experiments prove the power of fuzzy ARTMAP as a region classifier. After training, features of all regions in the database are extracted and classified. Simple index files enabling fast access to all regions from a given class are prepared to be used in the querying phase. To retrieve images containing a particular object, user opens an image and selects a query region together with a label in the graphical interface of our system. Then the system ranks all regions in the indexed set of the query class with respect to their L2 (Euclidean) distance to the query region and displays resulting images. During retrieval experiments, comparable class precisions with respect to exhaustive searching of the database are maintained which demonstrates e ectiveness of the classifier in narrowing down the search space.
487

Photochemical and Photophysical Studies of Synthetic Derivatives of the Green Fluorescent Protein Chromophore

Dong, Jian 07 July 2008 (has links)
We have synthesized dimethyl derivatives of the GFP chromophore (p-HOBDI) and several of its derivatives, and their photochemistry and photophysics were investigated using various steady-state and time-resolved techniques as follows. We first consider the effect of the £]-barrel on the optical properties of the GFP chromophore (p-HOBDI) experimentally by selective variation of the protonation state of chromophores and different solvents. Each of these forms shows a complex solvatochromic behavior and is governed by both polar and acid/base properties of the solvents. In contrast to their solution behavior, some O-alkyl GFP chromophore (alkoxy-BDI) derivatives exhibit large fluorescent enhancement in the solid state. The color of the crystalline BDI is tuned by substituent-mediated crystal packing, showing the potential applications in optoelectronic devices. Using femtosecond polarization-sensitive infrared (IR) spectrosceopy of the C=O stretching mode of the HOBDI, we have then discovered a near complete twisting around the ethylenic bridge between the phenolate and imidazolidinone groups upon electronic excitation. Cis/trans isomerization induced by the rotation around the bridge is thought to be responsible for the behavior of blinking in fluorescent protein; however, the mechanism of the thermal reverse isomerization is more problematic. Thus we synthesized BDI derivatives with decreasing para-donating ability, HO, CH3O, CH3, H, and Cl, and used a Hammett plot for the rate study. With a positive â value, we conceived, for the first time, a novel nucleophilic addition/elimination mechanism. Finally, the GFP chromophore falls into the general category of hydroxyarene photoacids, which exhibit high excited-state acidities but neutral ground states. A hydroxyl substituent at the meta position shows enhanced charge transfer and greater acidity in the excited state. As a result, we have demonstrated that the fast quenching of the excited state by internal conversion to the ground state is much slower in meta- than in para-HOBDI derivatives. This allows studies of this ultrafast intermolecular ESPT that competes with isomerization. The photoinduced dynamics of the meta isomer of GFP chromophore was further investigated using femtosecond transient absorption and fluorescence upconversion spectroscopies.
488

Biomaterials for Promoting Self-Healing of Bone Tissue

Piskounova, Sonya January 2011 (has links)
The present work addresses poor bone/implant integration and severe bone defects. In both conditions external stimuli is required for new bone to form. A multilayered functional implant coating, comprised of an inner layer of crystalline titanium dioxide (TiO2) and an outer layer of hydroxyapatite (HAP), loaded with bone morphogenetic protein-2 (BMP-2), was proposed as a tool for providing both improved initial bone formation and long-term osseointegration. The in vitro characterization of the implant coatings showed that TiO2 and HAP were more favorable for cell viability, cell morphology and initial cell differentiation, compared to native titanium oxide. Furthermore, significantly higher cell differentiation was observed on surfaces with BMP-2, indicating that a simple soaking process can be used for incorporating bioactive molecules. Moreover, the results suggest that there could be a direct interaction between BMP-2 and HAP, which prolongs the retention of the growth factor, improving its therapeutic effect. For treating severe bone defects a strategy involving BMP-2 delivery from hyaluronan hydrogels was explored. The hydrogels were prepared from two reactive polymers – an aldehyde-modified hyaluronan and a hydrazide-modified poly(vinyl alcohol). Upon mixing, the two components formed a chemically crosslinked hydrogel. In this work the mixing of the hydrogel components was optimized by rheological measurements. Furthermore, an appropriate buffer was selected for in vitro experiments by studying the swelling of hydrogels in PBS and in cell culture medium. A detection method, based on radioactive labeling of BMP-2 with 125I was used to monitor growth factor release both in vitro and in vivo. The results showed a biphasic release profile of BMP-2, where approximately 16 %  and 3 % of the growth factor remained inside the hydrogel after 4 weeks in vitro and in vivo, respectively. The initial fast release phase corresponded to the early ectopic bone formation observed 8 d after injection of the hydrogel formulation in the thigh muscle of rats. The hydrogel formulation could be improved by incorporation of HAP powder into the hydrogel formulation. Furthermore, bone formation could be increased by pre-incubation of the premixed hydrogel components inside the syringe prior to injection. Crushed hydrogels were also observed to induce more bone formation compared to solid hydrogels, when implanted subcutaneously in rats. This was thought to be due to increased surface area of the hydrogel, which allowed for improved cell infiltration.
489

Tracer development and PET studies : labeled proinsulin C-peptide and an EGFR-TK inhibitor /

Fredriksson, Anna, January 2002 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2002. / Härtill 6 uppsatser.
490

Part-based recognition of 3-D objects with application to shape modeling in hearing aid manufacturing

Zouhar, Alexander 12 January 2016 (has links) (PDF)
In order to meet the needs of people with hearing loss today hearing aids are custom designed. Increasingly accurate 3-D scanning technology has contributed to the transition from conventional production scenarios to software based processes. Nonetheless, there is a tremendous amount of manual work involved to transform an input 3-D surface mesh of the outer ear into a final hearing aid shape. This manual work is often cumbersome and requires lots of experience which is why automatic solutions are of high practical relevance. This work is concerned with the recognition of 3-D surface meshes of ear implants. In particular we present a semantic part-labeling framework which significantly outperforms existing approaches for this task. We make at least three contributions which may also be found useful for other classes of 3-D meshes. Firstly, we validate the discriminative performance of several local descriptors and show that the majority of them performs poorly on our data except for 3-D shape contexts. The reason for this is that many local descriptor schemas are not rich enough to capture subtle variations in form of bends which is typical for organic shapes. Secondly, based on the observation that the left and the right outer ear of an individual look very similar we raised the question how similar the ear shapes among arbitrary individuals are? In this work, we define a notion of distance between ear shapes as building block of a non-parametric shape model of the ear to better handle the anatomical variability in ear implant labeling. Thirdly, we introduce a conditional random field model with a variety of label priors to facilitate the semantic part-labeling of 3-D meshes of ear implants. In particular we introduce the concept of a global parametric transition prior to enforce transition boundaries between adjacent object parts with an a priori known parametric form. In this way we were able to overcome the issue of inadequate geometric cues (e.g., ridges, bumps, concavities) as natural indicators for the presence of part boundaries. The last part of this work offers an outlook to possible extensions of our methods, in particular the development of 3-D descriptors that are fast to compute whilst at the same time rich enough to capture the characteristic differences between objects residing in the same class.

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