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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.
261

Determination of metal in rice flour and plastic by slurrysampling electrothermal vaporization inductively coupled plasmamass spectrometry

Li, Po-Chien 07 July 2003 (has links)
Ultrasonic slurry sampling electrothermal vaporization dynamic reaction cellTM inductively coupled plasma mass spectrometry (USS-ETV-DRC-ICP-MS) has been applied to determine Cr, Cu, Cd, Hg and Pb in several rice samples. The influences of instrument operating conditions and slurry preparation on the ion signals were reported. Ascorbic acid was used as the modifier to enhance the ion signals. The background ions at the chromium masses were reduced in intensity significantly by using 0.4 ml min-1 NH3 as reaction cell gas in the dynamic reaction cell (DRC) while a q value of 0.6 was used. Since the sensitivities of Cr, Cu, Cd, Hg and Pb in rice flour slurry and aqueous solution were quite different, standard addition and isotope dilution methods were used for the determination of Cr, Cu, Cd, Hg and Pb in these rice samples. This method has been applied to the determination of Cr, Cu, Cd, Hg and Pb in NIST SRM 1568a rice flour reference material and two rice samples purchased from the market. The analysis results of the reference material agreed with the certified values. The results for the rice samples for which no reference values were available were also found to be in good agreement between isotope dilution method and standard addition method. The method detection limits estimated from standard addition curves were about 0.44, 1.7, 0.4, 0.53 and 0.69 ng g-1 for Cr, Cu, Cd, Hg and Pb, respectively, in original rice flour.Ultrasonic slurry sampling electrothermal vaporization dynamic reaction cellTM inductively coupled plasma mass spectrometry (USS-ETV-DRC-ICP-MS) has been applied to the determination of Cr, Cd and Pb in several plastic samples. The influences of instrument operating conditions and slurry preparation on the ion signals were investigated. NH4NO3 was used as the modifier to enhance the ion signals. The background ions at the chromium masses were reduced in intensity significantly by using NH3 as reaction cell gas in the DRC. Standard addition method and isotope dilution method were used for the determination of Cr, Cd and Pb in these plastic samples. This method was applied to the determination of Cr, Cd and Pb in two polystyrene and a polyvinyl chloride samples. The analysis results were found to be in good agreement between isotope dilution method and standard addition method. Furthermore, we digested these samples and analyzed the digested sample solutions by ultrasonic nebulization DRC ICP-MS. The analysis results were close to the isotope dilution and standard addition results. The precision between sample replicates was better than 3% with USS-ETV-DRC-ICP-MS method. The method detection limits estimated from standard addition curves were about 6.2-9.2, 1.1-1.6 and 8.4-11 ng g-1 for Cr, Cd and Pb, respectively, in original plastic samples.
262

A comparative study of HPr proteins from extremophilic organisms

Syed Ali, Abbas Razvi 12 April 2006 (has links)
A thermodynamic study of five homologous HPr proteins derived from organisms inhabiting diverse environments has been undertaken. The aim of this study was to further our understanding of protein stabilization in extremes of environment. Two of the proteins were derived from moderate thermophiles (Streptococcus thermophilus and Bacillus staerothermophilus) and two from haloalkaliphilic organisms (Bacillus halodurans and Oceanobacillus iheyensis); these proteins were compared with HPr from the mesophile Bacillus subtilus. Genes for three of these homologous HPr proteins were for the first time cloned from their respective organisms into expression vectors and they were over-expressed and purified in Escherichia coli. Stability measurements were performed on these proteins under a variety of solution conditions (varying pH, salinity and temperature) by thermal and solvent induced denaturation experiments. Stability curves were determined for every homologue and these reveal very similar conformational stability for these homologues at their habitat temperatures. The BstHPr homologue is the most thermostable and also has the highest G25; the stability of other homologues was ranked as Bst>Bh>St>Bs>OiHPr. Other key thermodynamic parameters, like Cp, have been estimated for all the homologues and it was found that these values are identical within errors of estimation. Also, it was found that the values of TS are very similar for these homologues. Together these observations allow us to propose a thermodynamic mechanism toward achieving higher Tm. The crystal structures of the BstHPr and a single tryptophan-containing variant (BstF29W) of this homologue are also reported here. Also reported is a domain-swapped dimeric structure for the BstF29W variant, together with a detailed investigation into the solution oligomeric nature of this protein. The crystal structure of BstHPr is analyzed to enumerate various stabilizating interactions like hydrogen bonds and salt-bridges and these were compared with those for the mesophilic homologue BsHPr. Finally, an analysis of sequence alignments together with structural information for these homologues has allowed design of numerous variants of both Bs and BstHPr. A detailed thermodynamic study of these variants is presented in an attempt to understand the origins of the differences in stability of the HPr homologues.
263

Multimedia eller inte multimedia, det är frågan.

Blomquist, Ann-Charlotte, Aggerstam, Helena January 2009 (has links)
<p>Is it possible, and suitable, to use multimedia in classic literature studies at Swedish upper secondary school? What alternatives are there?  Is there any foundation in the curriculum for an expanded conception of text as in multimedia?  Will the conception literacy support use of multimedia in classic literature studies, and in what ways? How do we generally look upon the definition text, is it only printed letters, or something more? To get an answer to the questions we decided to examine a number of theories, Gardner’s theory about the different intelligences, the conception literacy and the expanded text concept. In these three theories we took our starting-point for the following work. The main subjects became two interactive sights on Internet and one CD-ROM, all containing classic literature. Our previous knowledge in this subject field was very meager.  This work has given us an opportunity to discover some of the multimedia that is available, and the result we have come to is that multimedia absolutely belongs in studies of classic literature as well as in other subjects. We think it is necessary to pay attention to multimedia in the future education, because of the text flow in the society. Text flow is much more than just printed letters, for example web sites with further more experiences such as pictures/paintings and music, which makes a comprehensive picture. As we see it, this conclusion has support in the theories.</p>
264

Interaktivreklamfilm-en CD-ROM-produktion för Alding Webshop Maker / Interactive commercial : a CD-ROM demonstration for Alding Webshop Maker

Petersson, Jonas January 2002 (has links)
<p>Denna rapport visar hur en reklamfilm för en specifik produkt har utvecklats, i form av en CD-ROM-produktion. Företaget Alding AB har efterfrågat reklamfilmen för sin produkt Alding Webshop Maker 1.3. </p><p>Flera olika programvaror har använts vid genomförandet, varav ljudredigeringsprogrammet Sonic Foundry Sound Forge 5.0 och bildredigeringsprogrammet Adobe Photoshop 5.5 hör till de mest frekvent använda. Med hjälp av programmet Macromedia Director 7.0 har sammanställningen av reklamfilmen utförts. Rapporten behandlar de olika problem som uppstått under arbetets gång samt hur de har kunnat undanröjas. </p><p>Efter färdigställandet av CD-ROM-produktionen började Alding AB att använda den. På detta sätt fick de ytterligare en kanal varigenom de kan sprida information om Alding Webshop Maker 1.3. Den enkla och informativa reklamfilmen gör att presumtiva kunder får upp ögonen för produkten.</p>
265

Synthetic CD40L mimetics Biological effects and potential applications in immunotherapy /

Wieckowski, Sébastien Fournel, Sylvie. Guichard, Gilles. January 2008 (has links) (PDF)
Thèse de octorat : Aspects moléculaires et cellulaires de la biologie. Immunologie : Strasbourg 1 : 2007. / Thèse soutenue sur un ensemble de travaux. Titre provenant de l'écran-titre. Notes bibliogr.
266

CD22 regulates B cell fate via two signaling domains within its cytoplasmic tail /

Otipoby, Kevin L., January 2000 (has links)
Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 89-105).
267

Predicting ion adsorption onto the iron hydroxide goethite in single and multi-solute systems

Mangold, Jeremiah Edward 03 March 2014 (has links)
Surface complexation models (SCMs) have proven to be a useful tool in predicting ion adsorption at the mineral – water interface. In particular, previous research has shown that the Diffuse Layer Model (DLM), Constant Capacitance Model (CCM), and Triple Layer Model (TLM), are all capable of predicting ion adsorption in relatively simple single solute systems. To better simulate the environmental conditions experienced by groundwater sources present in the Earth’s subsurface, experimental adsorption studies have been conducted for more complex multi-solute systems. Under these conditions, SCMs have not proven to be reliable in consistently predicting ion adsorption behavior for the adsorbates of interest. This inability of these SCMs to predict ion adsorption for more complex, multi-solute systems is thought to stem from the variable site density (NS) values utilized in these models. In this research, a methodology was developed for characterizing mineral surface heterogeneity that allows for the different site density values predicted from crystallography, microscopic imaging, tritium exchange, surface saturation data, and surface charging data to all be explained using a single unified theory. This methodology was applied to a goethite mineral sample used in performing batch adsorption studies in single and bi-solute systems with Cd(II), Pb(II), and Se(IV). The adsorption behavior of these adsorbates onto the goethite sample was successfully predicted using the Charge Distribution Multi-Site Complexation (CD-MUSIC) Model and surface complexes consistent with spectroscopic data and computational molecular modeling simulations. A second, separate modeling study was performed using CD-MUSIC to predict Hg(II) adsorption onto different goethite samples of varying size and crystal morphology in single and multi-solute systems. In this study, site density values were predicted for the mineral samples studied utilizing a linear relationship observed for goethite between specific surface area and proton reactive site density. The CD-MUSIC model proved successful in predicting Hg(II) adsorption over all conditions studied while employing only surface complexes consistent with molecular scale analyses. In addition, a novel method for quantifying carbonate’s presence in experimental systems was developed. / text
268

Application of soluble CD14 and a trivalent vaccine to prevent mastitis caused by Escherichia coli and Staphylococcus aureus

Lee, Jai-Wei, 1970- January 2003 (has links)
Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) are the most prevalent pathogens to induce mastitis. The pathogenesis of infections induced by E. coli is sophisticatedly modulated by lipopolysaccharide (LPS), LPS binding protein, membrane CD14 (mCD14), and soluble CD14 (sCD14). In the first study, administration of recombinant bovine sCD14 (rbosCDl4) significantly reduced the fatality of LPS challenged mice and the severity of mouse mastitis in terms of clinical signs, bacterial load, and TNF-alpha production. Before investigating the potential of this strategy in dairy cows, endogenous sCD14 in milk was characterized. Based on the data of 396 quarters, the milk concentration of sCD14 was 6.67 +/- 0.44 mug/ml. The stages of lactation affected the concentration of sCD14 in milk, which was higher in transitional milk (0--4 days postpartum). Milk sCD14 also increased during an intramammary LPS challenge, which paralleled with SCC increase. The protective effect of sCD14 on bovine E. coli mastitis was then investigated. It was shown that rbosCDl4 sensitized the mammary gland to recruit leukocytes in response to LPS. To prove that the early recruitment of leukocytes plays a role in preventing intramammary E. coli infections, E. coli mastitis was induced in 9 dairy cows with or without 100 mug rbosCD14. Quarters challenged with E. coli plus rbosCD14 had a more rapid recruitment of neutrophils, a faster clearance of bacteria, reduced concentrations of TNF-alpha and IL-8 in milk, and reduced clinical symptoms than quarters injected with saline. / For S. aureus mastitis, a newly designed trivalent whole-cell vaccine being composed of the most dominant serotypes (T5, T8, and T336) was evaluated. The vaccine was immunized with or without either one of the two adjuvants, aluminum hydroxide (ALUM) and Freund's incomplete adjuvant (FICA). The vaccine, with or without the presence of adjuvants, increased antigen-specific IgG1, IgG2, but not IgM, in serum. However, all formulations only had limited effects on lymphocyte subsets, interferon (IFN)-gamma mRNA expression, and neutrophil phagocytosis in comparison with the control. / Taken together, the results indicated that increasing the concentration of sCD14 in milk might be a potential strategy to prevent or reduce severity of E. coli mastitis. On the other hand, both ALUM and FICA did not augment the immune responses when formulated with trivalent vaccine. A more immunostimulatory adjuvant will be required to improve the efficacy of the novel trivalent vaccine against S. aureus mastitis.
269

Nuclear Structure Study of Cd-110 through Internal Conversion Electrons

Jigmeddorj, Badamsambuu 24 August 2012 (has links)
For many years, Cd-110 has been considered the classic example of a vibrational nucleus within both the Collective Model and the Interacting Boson Model (IBM). As a vibrational nucleus, Cd-110 exhibits multi-phonon states. Recent studies on other cadmium isotopes have shown a breakdown of vibrational motion at the three-phonon level. The latest study on Cd-112 suggests that some of these excitations may instead result from intruder bands. The study through internal conversion electrons is important to investigate intruder structures in Cd-110, using the enhanced E0 transitions between intruder states and spherical phonon states as a signature. The nuclear structure of Cd-110 has been studied with In-110 beta decay through internal conversion electrons performed at TRIUMF using the 8pi spectrometer. The level scheme of Cd-110 through internal conversion electron transitions was constructed using the electron-gamma coincidence matrix. The sub-shell ratios and multipolarities are determined and compared with the evaluated data set. The absolute internal conversion coefficients for some mixed transitions were determined using an internal calibration efficiency for Si(Li) detector and relative efficiency for HPGe detector. The 396 keV and 708 keV E0 transitions have been observed between intruder and spherical phonon states. The E0 transition strength of 0.115(71) was determined for 708.21 keV line.
270

Evaluation of a science laboratory safety CD-ROM [electronic resource]

Walters, David Clyde, University of Lethbridge. Faculty of Education January 1995 (has links)
Educational compact discs or CD-ROM's are appearing more frequently in the classroom. An educational science laboratory safety CD was developed at the University of Lethbridge in 1994. This case study is an evaluation of the U. of L. safety CD to determine how well the disc facilitates independent, student directed learning. The study involved forty four High School students at Matthew Halton Community School in Pincher Creek, Alberta. The students used the CD in Biology and Chemistry classes. The survey included observations, questionnaire, and interviews to solicit student reaction to the disc. Students agreed that the CD was easy to use and that it was well suited for independent learning. They also made suggestions for further improvements. / 1 compact disk ; 4 3/4 in.

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