The reactions of 2,5-dimethoxytetrahydrofuran and 2,6-dimethoxytetrahydropyran with halotrimethylsilanes have unexpectedly given 1,4-dichloro-1,4-dimethoxybutane and 1,5-dihalo-1,5-dimethoxypentane, respectively. Some features of this reaction were investigated and a mechanism was proposed. / It was shown that 1,4-dichloro-1,4-dimethoxybutane was a mild reagent for the conversion of primary amine and amide to the corresponding N-alkyl and N-acyl pyrroles, respectively. As part of these applications, 2-(2-formylpyrrol-1-yl)-4-methylpentanoic acid, a compound isolated from flue-cured tobacco, was synthesized. / The use of acylpyrroles as active acylating agents was investigated. The preparation of (alpha)-substituted derivatives from ethyl 2-(1-pyrrolyl)acetate was achieved by using lithium hexamethyldisilazide as base. / As part of a synthetic study directed toward Nonactin, the bicyclic enol form 152 and keto form 153 were obtained by the reaction of 1-methoxyl-1,3-bis(Trimethylsiloxy)-1,3-pentadiene with 2,5-dimethoxytetrahydrofuran. The configurations at C-4 were determined with the aid of 200 MHz ('1)H nmr decoupled spectra. / A new rearrangement of (alpha)-acyloxy esters into 2-hydroxy-3-keto esters was observed.

No description available.

Zugl.: München, Univ., Diss., 2009

No description available.

I uppsatsen redovisas en studie som gjorts om ett multiplikationsprojekt, som går under namnet Multiplikationsklubben, vilket genomförs av lärare på två skolor i Mellansverige. Projektet syftar till en större måluppfyllelse i matematik genom en bättre automatiserad multiplikationstabell hos eleverna i grundskolans tidiga år. I studien granskas bakgrund, motiv och mål med Multiplikationsklubben. Elevers och lärares olika uppfattningar om multiplikation och tabellkunskaper samt syn på vad multiplikation innebär jämförs med de uppfattningar som olika forskare uttrycker i litteraturen. Genom intervjuer med två lärare och tolv elever på en av skolorna som deltar i Multiplikationsklubben analyseras projektet mot bakgrund av forskning i ämnet. Många av de uppfattningar och idéer som elever och lärare uttrycker återfinns i tidigare studier samt i populärvetenskaplig litteratur inom ämnet, t.ex. att en automatiserad multiplikationstabell hos eleven är grunden inom mycket av matematiken. En annan uppfattning är den att en automatiserad multiplikationstabell kan nås genom förståelse för tabellen och en variation i multiplikationsträningen vilket generar en motivation hos eleven i träningen. Studiens resultat visar att förståelsen för tabellen kan uppnås via en praktisk multiplikationsträning genom multiplikationsspel och ett klossbyggande som strävar mot en konkretisering av multiplikations-tabellen. Multiplikationsprojektet syftar till att lyfta matematiken och nå en högre måluppfyllelse hos eleverna genom en mer motiverande undervisning.

Self-regulated learning (SRL) and higher-order thinking (metacognitive processes) are important in education because they contribute to effective learning and improved academic performance. These processes may be facilitated by the implementation of computer technology in the classroom. This research project examined the use of computer technology among elementary school students and possible effects on self-regulated learning and metacognitive processes, including the ability to plan, monitor, evaluate one’s own work, and apply specific learning strategies. Two main research questions were investigated: (1) Do elementary school students demonstrate SRL metacognitive processes when they use computers and paper-pencil for reading-relating tasks, and what are the key SRL metacognitive processes? (2) Are there differences in SRL metacognitive processes between computer-based and paper-pencil reading tasks in elementary grades? Recruitment of students occurred at the local school district’s after-school programs. A total of 52 students from Grades 2-5 consented to participate in two conditions, a computer-based and a paper-pencil reading task, each lasting approximately 30 minutes. Observations, ratings, and semi-structured interviews were conducted. The quantitative portion included descriptive and correlational statistics. Differences in SLR metacognitive constructs between conditions and between grades were explored. Inferential statistics employed a 2 x 4 (condition-by-grade) mixed-model Analysis of Variance and follow-up tests. The qualitative portion included primary analytic strategies, thematic analysis, and triangulation across data sources. The results indicated that metacognitive self-regulated learning skills were present in students of primary grades. There were no differences between grades or between conditions for most regulation of cognition constructs except for control and evaluation practices. Among knowledge of cognition constructs, conditional knowledge was higher in the paper than in the computer reading assignment across grades. The qualitative findings corroborated the quantitative results. Students in primary grades demonstrated SRL metacognitive processes, and these were more common in the paper than in the computer condition. These findings are explained by the familiarity with the reading medium, the integration of multimedia and verbal cues, the speed for corrective actions, and the use of prior knowledge. These important insights can contribute to improved academic performance and higher order thinking among young students. The results also suggest that students can benefit from focused instruction to perform transfer of knowledge between the two reading formats - computer and paper.

The work concerns to structural characterization of two important proteins of 2'-5' oligoadenylate pathway participating in an immune response of organism to a viral infection. Studied proteins were ankyrin domain of mouse RNase L, the C-terminal part of human phosphodiesterase 12 and the complete human phosphodiesterase 12. The proteins were characterized by Raman spectroscopy, infrared spectroscopy, electronic circular dichroism, dynamic light scattering and in addition by two non-spectroscopic methods- differential calorimetry and electrophoresis. For each protein the secondary structures, thermal stability, weight of oligomers and generally a basic characterization by above mentioned methods were provided.

Two cellular innate responses, the dsRNA protein kinase (PKR) pathway and the 2'-5' oligoadenylate synthetase (OAS)/RNase L pathway, are activated by dsRNAs produced by viruses and reduce translation of host and viral mRNAs. PKR activation results in eIF2a phosphorylation. As a consequence of eIF2a phosphorylation, stress granules (SGs) are formed by the aggregation of stalled SG proteins with pre-initiation complexes and mRNA. West Nile virus (WNV) infections do not induce eIF2a phosphorylation despite upregulation of PKR mRNA and protein suggesting an active suppression of PKR activation. Assessment of the mechanism of suppression of PKR activation in WNV-infected cells indicated that WNV infections do not induce PKR phosphorylation so that active suppression is not required. In contrast to infections with "natural" strains of WNV, infections with the chimeric W956 infectious clone (IC) virus efficiently induce SGs in infected cells. After two serial passages, the IC virus generated a mutant (IC-P) that does not induce SGs efficiently but does induce the formation of NS3 granules that persist throughout the infection. This mutant was characterized. 2'-5' oligoadenylate synthetases (OAS) are activated by viral dsRNA to produce 2-5A oligos that activate RNase L to digest viral and cellular RNAs. Resistance to flavivirus-induced disease in mice is conferred by the full-length 2'-5' oligoadenylate synthetase 1b (Oas1b) protein. Oas1b is an inactive synthetase that is able to suppress the in vitro synthetase activity of the active synthetase Oas1a. The ability of Oas1b to inhibit Oas1a synthetase activity in vivo and to form a heteromeric complex with Oas1a was investigated. Oas1b suppressed 2-5A production in vivo. Oas1a and Oas1b overexpressed in mammalian cells co-immunoprecipitated indicating the formation of heteromeric complexes by these proteins. Unlike mice, humans encode a single OAS1 gene that generates alternatively spliced transcripts encoding different isoforms. Synthetase activity has previously been reported for only three of the isoforms. The in vitro synthetase activity of additional OAS1 isoforms was analyzed. All tested isoforms synthesized higher order 2-5A oligos. However, p44A only produced 2-5A dimers which inhibit RNase L.

No description available.

Les colorants organiques du proche infrarouge présentent un intérêt majeur dans différent secteurs technologiques. Les travaux présentés dans cette thèse portent sur le développement de ce type de chromophores à partir d’unités quinones possédant une conjugaison électronique particulière : les 2,5-diamino-1,4-benzoquinone-diimines (DABQDI). De nouvelles DABQDI ont pu être synthétisées et leur utilisation comme ligand a notamment permis d’obtenir des complexes absorbant du domaine visible jusqu’à celui du proche infrarouge. Ces unités DABQDI ont également pu être incorporées au sein de macrocycles, analogues de porphyrines, appelés azacalixphyrines, capables d’absorber la lumière jusqu’à 1000 nm. / Near infrared dyes play a significant role in various technological sectors. The present PhD manuscript concerns the development of such chromophores built on quinone units that have a particular electronic delocalization: the 2,5-diamino-1,4-benzoquinone-diimines (DABQDI). New DABQDI have been synthesized and their use as ligand can provide complexes absorbing from the visible to the near infrared domain. DABQDI units were also incorporated in macrocycles, analogous of porphyrins, called azacalixphyrins, able to absorb light up to 1000 nm.