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Vertaisverkot ovat osoittautuneet hyvin suosituiksi kiinteässä Internetissä. Akateemisesta näkökulmasta mielenkiintoista on, että matkapuhelinverkkoa varten suunniteltuja vertaisverkkoja ei vielä ole. Tässä diplomityössä käymme aluksi läpi mobiilivertaisverkosta tehtyjä tutkimuksia. Tämän jälkeen kuvaamme uudenlaista lähestymistapaa, joka käyttää SIP (Session Initiation Protocol) -protokollaa vertaisverkon merkinantosanomien kuljettamiseen. Tästä lähestymistavasta, joka tarjoaa useita etuja, käytämme nimeä P2P-over-SIP. Seuraavaksi kuvaamme mobiilivertaisverkosta tehdyn toteutuksen. Erityisesti kuvaamme tekemämme supersolmun ohjelmistototeutuksen, jonka avulla puolikeskitetty järjestämätön arkkitehtuuri muodostuu. Testaamme toteutusta oikeudenmukaisissa skenaarioissa ja tuloksia analysoimalla teemme päätelmiä arkkitehtuurin soveltuvuudesta laajempaan käyttöön. Lopuksi pohdimme aiheeseen liittyviä kehitysmahdollisuuksia.
The heterogeneously catalyzed reductive amination of phenolics from lignin is considered an attractive sustainable route for the synthesis of primary or high-order aromatic and aliphatic amines. Here, the reductive amination of phenol with cyclohexylamine was studied, and insights into the role of the catalyst support, metal nanoparticle sizes, and acidic properties were provided. Bulk and surface characterization, IR experiments, and kinetic measurements were performed, and their results were correlated with the catalytic performance and the content of Lewis acid sites (Pd/Al2O3 > Pd/C > Pd/SiO2). The Lewis acid sites in the support and those formed by H2 spillover assisted phenol hydrogenation and C=N bond activation, enhancing the formation of secondary amines (selectivity >90%). The Pd coordination in the particles strongly affected the catalytic activity, indicating that phenol amination is a structure-sensitive reaction. The turnover frequency vs. dispersion profiles combined with the site distributionsin the Pd particles (edge, corner, and terraces) indicate that low-coordination sites favor phenol amination, which was confirmed via diffuse reflectance infrared spectroscopy with Fourier transform and high-resolution transmission electron microscopy. This study could contribute to the upcycling of fresh and recycled lignin fractions to produce aromatic and aliphatic amines.
Abstract Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.