2 resultados para Foam-mat

em Academic Archive On-line (Stockholm University


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Denna studie undersöker sociala mediers påverkan på människor med fokus på mat och hälsa. Med hjälp av en kvantitativ enkätstudie har vi undersökt hur och på vilket sätt de sociala medierna spelar in i hur människor äter. Fokus ligger på vilket medie människor i åldern 18 år och uppåt väljer för att få inspiration till hälsosam mat, i vilken grad sociala medier förändrat människors medvetenhet och intresse kring hälsa och mat samt huruvida den här påverkan upplevs som positiv (inspirerande) eller negativ (stress/förvirring). Resultatet visar att de sociala medierna inte tagit över som inspirationskälla då de traditionella medierna, så som tidskrifter, TV och böcker, visade sig vara vanligast för att inspireras och skaffa sig inspiration kring mat. De sociala medierna fungerar snarare som ett komplement och har större popularitet hos den yngre generationen. Vidare visar studien att sociala medier delvis bidragit till att öka medvetenhet och intresse kring mat och hälsa. Majoriteten angav att de snarare inspireras än känner stress/förvirring till de hälsobudskap kring mat som florerar på sociala medier och studien visade ett tydligt mönster att kvinnor är både mer negativt och positivt påverkade än männen.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The major part of this thesis concerns the development of catalytic methodologies based on palladium nanoparticles immobilized on aminopropyl-functionalized siliceous mesocellular foam (Pd0-AmP-MCF). The catalytic activity of the precursor to the nanocatalyst, PdII-AmP-MCF is also covered by this work. In the first part the application of Pd0-AmP-MCF in Suzuki-Miyaura cross-coupling reactions and transfer hydrogenation of alkenes under microwave irradiation is described. Excellent reactivity was observed and a broad range of substrates were tolerated for both transformations. The Pd0-AmP-MCF exhibited high recyclability as well as low metal leaching in both cases. The aim of the second part was to evaluate the catalytic efficiency of the closely related PdII-AmP-MCF for cycloisomerization of various acetylenic acids. The catalyst was able to promote formation of lactones under mild conditions using catalyst loadings of 0.3 - 0.5 mol% at temperatures of up to 50 oC in the presence of Et3N. By adding 1,4-benzoquinone to the reaction, the catalyst could be recycled four times without any observable decrease in the activity. The selective arylation of indoles at the C-2 position using Pd-AmP-MCF and symmetric diaryliodonium salts is presented in the third part. These studies revealed that Pd0-AmP-MCF was more effective than PdII-AmP-MCF for this transformation. Variously substituted indoles as well as diaryliodonium salts were tolerated, giving arylated indoles in high yields within 15 h at 20 - 50 oC in H2O. Only very small amounts of Pd leaching were observed and in this case the catalyst exhibited moderate recyclability. The final part of the thesis describes the selective hydrogenation of the C=C in different α,β-unsaturated systems. The double bond was efficiently hydrogenated in high yields both under batch and continuous-flow conditions. High recyclability and low metal leaching were observed in both cases.