Browsing by Title

Kasvillisuus emittoi biogeenisia haihtuvia yhdisteitä. Niitä hapettaa ilmakehässä erityisesti O3-, OH- ja NO3-radikaalit. Osa hapetustuotteista on heikosti haihtuvia, jolloin ne voivat osallistua sekundäärisen orgaanisen aerosolin (SOA) muodostukseen. Koska aerosolihiukkaset toimivat mm. pilvipisaroiden tiivistymisytiminä, on näillä suuri vaikutus ilmastoon. Hapetustuotteisiin ja niiden haihtuvuuksiin vaikuttavat myös muut ilmakehän reaktiiviset yhdisteet, kuten esimerkiksi typen oksidit (NOx). Syklisen biogeenisen yhdisteen otsonihapetus on yksi reaktioista, jossa muodostuu tehokkaasti reaktiivisia peroksiradikaaleja (RO2). Nämä voivat nopean autoksidaatioprosessin kautta saavuttaa korkeita happilukuja. Peroksiradikaalit reagoivat myös muiden radikaalien tai toisten peroksiradikaalien kanssa. Reaktioketjut päättyvät lopulta pysyvämpien tuotteiden muodostumiseen. Muodostuneista hyvin hapettuneista orgaanisista molekyyleistä (HOM) osa on monomeerejä ja osa kahdesta monomeeristä koostuvia suurempia dimeerejä. Kun ympäristössä on typen oksideja, myös organonitraatteja muodostuu. Tässä työssä tarkastellaan syklohekseenin hapettumisesta syntyviä tuotteita. Syklohekseeni on yksinkertainen syklinen hiilivety (C6H10), jolla on endosyklinen kaksoissidos. Sellainen perusrakenne on yhteinen myös monille ilmakehässä esiintyville monimutkaisemmille biogeenisille yhdisteille kuten esimerkiksi α-pineenille. Tutkimus tehtiin teflonkammiossa ja hapettimena käytettiin otsonia, joka on tärkeä ilmakehässä vuorokauden ympäri vaikuttava hapetin. Kammiossa tehtiin myös NOx- ja siemenaerosolikokeita, jotta voitaisiin tarkastella typen oksidien vaikutusta sekä tuotteiden haihtuvuuksia. Tätä tutkielmaa varten prosessoitiin CI-APi-TOF -massaspektrometrillä mitattua raakadataa. Analysoinnissa hyödynnettiin sen lisäksi myös muuta valmiiksi prosessoitua dataa. CI-APi-TOF -raakadata prosessoitiin TofTools-spektrianalyysityökalulla, joka pyörii Matlab-ohjelmassa. Myös muu analyysi tehtiin Matlab R2016:lla. Siemenkokeissa heikoimmin haihtuvat yhdisteet tiivistyivät tehokkaasti siemenaerosolin pinnalle. Haihtuvuutta heikentävien tekijöiden havaittiin olevan suuri massa, sekä suuri happiluku. Lukuun ottamatta organonitraatteja, yhdisteiden haihtuvuus laski selkeästi suurin piirtein massavälillä 225-250 Th ja happiluvusta 7. Organonitraatit olivat sen sijaan haihtuvampia kuin muut lähimassaiset yhdisteet (haihtuvuuden lasku n. 250-300 Th). NOx lisäsi keskimääräistä haihtuvuutta myös siten, että sen reaktioissa muodostui enemmän haihtuvampia monomeerejä, samalla kun heikosti haihtuvien dimeerien muodostuminen väheni. Tämä viittaa siihen, että NOx voi heikentää SOA:n kasvua syklohekseenin kaltaisten yhdisteiden hapettumisesta.

Symbolisk integrering innebär att hitta den obestämda integralen till en given funktion f, dvs. att hitta en sådan funktion g att g(x) = ∈t f(x) dx. Den här avhandlingen behandlar det specialfall där integranden f är en rationell funktion, vilket betyder att f kan skrivas som kvoten av två polynom. I kapitel 2 introduceras den grundläggande algebra som vi behöver. I kapitel 3 stiftar vi bekantskap med Euklides algoritm för att hitta den största gemensamma delaren, samt utvecklar algoritmer för lösning av diofantiska ekvationer och uppdelning i partialbråk. I kapitel 4 definierar vi resultanten av två polynom. Kapitel 5 behandlar kvadratfri faktorisering av polynom, och vi bevisar Yuns algoritm för kvadratfri faktorisering. I kapitel 6 tar vi in differentialalgebraiska begrepp och använder hermitesk reduktion för att skriva om integralen av en godtycklig rationell funktion i en rationell och en logaritmisk del. I kapitel 7 inför vi logaritmiska och algebraiska utvidgningar och beräknar den logaritmiska delen av integralen med Rothstein-Tragers metod. Resultaten sammanfattas i en deterministisk algoritm för symbolisk integrering av rationella funktioner.

RFID technology emerged as the promising technology for its ease of use and implementation in the ubiquitous computing world. RFID is deployed widely in various applications that use automatic identification and processing for information retrieval. The primary components of an RFID system are the RFID tag (active and passive), the reader and the back-end server (database). Cost is the main factor that drove RFID tags to its immense utilization in which passive tags dominate in today's widely deployed RFID practice. Passive tags are low cost RFID tags conjoined to several consumer products (like clothes, smart cards and devices, courier, container, etc) for the purpose of unique identification. Readers on the other hand act as a source to track and record the passive RFID tag's activities (like modifications, updates and authentication). Due to the rapid growth of RFID practice in the past few years, measures for consumer privacy and security has been researched. The uncertainties that arise with the passive RFID tags are handling of user's private information (like name, ID, house address, credit card number, health statement, etc) which are posed to considerable threat from the adversary. Passive tags are inexpensive and contain less overhead and are considered good performers and consequently lack in providing security and privacy. Lightweight cryptography is an area of cryptography developed for low cost resourced environment. Mutual authentication is defined as the process of verifying an authorized tag and a reader (reader and server respectively) by an agreed algorithm to mutually prove their legitimacy with each other. Adversary is a third party who tries to hear the ongoing communication between the tag and the reader (reader and server respectively) anonymously. In this thesis, symmetric lightweight ciphers like Present and Grain are introduced as mutual authentication protocols to rescue the privacy aspects and properties of the RFID tags. These ciphers are simple, faster and suitable to implement within the passive RFID network and reasonably lay a foundation for the preservation of privacy and security of the RFID system. Lightweight ciphers use hash functions, pseudo random generators, SP networks and linear feedback shift registers to randomize data while mutual authentication scheme uses lightweight ciphers to manage authorize the legitimacy of every device in the RFID network.

Suurimassaisia synteettisiä polymeerejä käytetään mitä erilaisimmissa prosesseissa eri teollisuuden aloilla, esimerkiksi vedenkäsittelyyn liittyvissä applikaatioissa. Tällaisten suurimassaisten polymeerien (10 – 20 miljoonaa g/mol) analysointi ja kvantitatiivinen määritys esimerkiksi vesinäytteistä on usein ongelmallista ja monesti mahdotonta polymeeriliuoksen suuren viskositeetin ja huonon erottumisen vuoksi etenkin nestekromatografisilla menetelmillä. Tämän tutkielman tavoitteena oli kehittää uusi kapillaarielektroforeettinen, kvantitatiivinen analyysimenetelmä suurimassaisten polymeerien analysointiin nestekromatografisten menetelmien rinnalle. Tutkielman kirjallisessa osassa kartoitetaan synteettisten polymeerien ominaisuuksia ja kapillaarielektroforeesin mahdollisuuksia suurten polymeerien karakterisoinnissa. Synteettisten polymeerien erottumisprosessi kapillaarielektroforeesissa poikkeaa pienten yhdisteiden erottumisesta ja voi perustua esimerkiksi molekyylin varaustiheyteen tai haaroittumiseen. Menetelmällä voidaan saada tietoa esimerkiksi polymeerimolekyylin lohkorakenteesta tai misellisestä rakenteesta. Lisäksi kapillaarielektroforeesilla voidaan määrittää polymeerien pitoisuuksia kvantitatiivisesti. Kapillaarigeelieketroforeesia voidaan puolestaan käyttää esimerkiksi polymeerin moolimassan ja –jakauman määrittämiseen. Tutkielman kokeellisessa osassa kehitettiin kapillaarielektroforeettinen määritysmenetelmä lineaariselle Kemirassa valmistetulle satunnais-kopolymeerille (AMD-ko-AA), jonka varaustiheys oli 58 mol-%. Lisäksi tutkittiin mahdollisuutta analysoida pinta-aktiivisia aineita samasta vesinäytteestä ja samalla menetelmällä. Pinta-aktiivisen aineen mallikemikaalina käytettiin kaupallista natriumdodekyylibentseenisulfonaattia. Polymeerin suuren moolimassan vuoksi se hajotettiin ennen analyysiä kapillaariviskometrilla. Alustavissa testeissä CE:llä kummallekin mallikemikaalille etsittiin soveltuva elektrolyyttiliuos. Jatkotestit tehtiin kaupallisella boraattipuskurilla ja menetelmä optimoitiin kapillaarielektroforeettisten parametrien osalta. Optimoinnin jälkeen menetelmälle tehtiin suppea validointi käytettävissä olleen laiteajan puitteissa. Lopuksi kehitetyllä menetelmällä analysoitiin prosessivesiä ja niistä määritettiin sekä polymeeri- että surfaktanttipitoisuus.

Self-assembled structures of poly(2-isopropyl-2-oxazoline) (PiPOx) and poly(L-lactide) (PLLA) block copolymers in water were studied by dynamic light scattering (DLS) and UV-VIS spectroscopy (UV-VIS). The block copolymers were prepared by azide-alkyne cycloaddition between PiPOx and PLLA homopolymers. The homopolymers were prepared via ring-opening polymerization (ROP) techniques. The kinetics of the cationic ROP of PiPOx was investigated. The self-assembled structures were prepared via four different methods: nanoprecipitation, solvent exchange, dialysis, and thin film rehydration. Self-assembled structures prepared from solvent exchange and dialysis had larger hydrodynamic radii than particles prepared from nanoprecipitation, due to a slower change in solvent quality. According to the Rg/Rh values, spherical structures were formed after nanoprecipitation. When the particles were heated to 50 °C, a sphere-to-rod transition took place. Self-assembled structures prepared via solvent exchange exhibited thermo-responsiveness when the PiPOx block was long enough. Surprisingly, the small structures prepared via nanoprecipitation did not show any thermo-responsiveness.

In this master’s thesis, linear zwitterionic poly(ethylene imine) methyl-carboxylates (l-PEI-MCs) were synthesized through a four-step synthesis. The synthesis started with the polymerization of 2-ethyl-2-oxazoline (EtOx) monomers into poly(2-ethyl-2-oxazoline) (PEtOx) homopolymers with polymerization degree of 50 and 100. Living cationic ring-opening polymerization (LCROP) enabled a good control over the molecular weights. Subsequently, the side chains of PEtOxs were cleaved off by acidic hydrolysis. This resulted in linear poly(ethylene imine)s (l-PEIs) bearing a secondary amine group in repeating units of the polymer chain. These amine units were then functionalized with methyl-carboxylate moieties by first introducing tert-butyl ester functionalities to l-PEI chains, and subsequently cleaving off the tert-butyl groups. The final polymer is a polyzwitterion, featuring both an anionic carboxylate and a cationic tertiary amine group within a single repeating unit. Polymers produced in each step were characterized via 1H-NMR and FT-IR spectroscopy and their thermal properties were analyzed by differential scanning calorimetry (DSC). The molecular weights and dispersities (Ð) of PEtOx polymers were additionally estimated by gel permeation chromatography (GPC). Via 1H-NMR, the degree of polymerization for PEtOxs and the hydrolysis degree for l-PEIs were determined. FT-IR gave a further insight into the structures of polymers, successfully confirming the ester functionality of modified l-PEI. The disappearance of the tert-butyl proton signal in 1H-NMR spectrum after deprotection verified the successful removal of tert-butyl groups, resulting in the final product with methyl-carboxylate functionalities. By DSC, different thermal transitions, i.e., glass transition (Tg), melting (Tm) and crystallization (Tc), were observed, and the effects of molar mass and polymer modifications on these transitions were being investigated. The state of the art explores the literature regarding synthesis and properties of poly(2-oxazoline)s (POx), poly(ethylene imine)s (PEIs), and polyzwitterions. The theory behind living cationic ring-opening polymerization of 2-oxazolines and acidic hydrolysis of POxs is described. Different post-polymerization modification strategies to functionalize PEIs are being discussed. In addition, possible applications for each of these polymer classes are shortly outlined.

Prostate cancer is the most common cancer in male population in the western world. In Finland around 5000 men are diagnosed with it every year. Most patients are diagnosed with localized prostate cancer, when the prognosis is good: the relative 5-year survival is over 90%. The metastasized form of prostate cancer can be considered fatal, since the 5-year survival rate for patients with metastases in distant organs is about 29%. Early diagnosis and clear and definite understanding of patient's tumor profile are fundamental parts of optimized treatment of prostate cancer. Proliferation and antiapoptotic characteristics of prostate cancer tissue is caused by altered androgen receptor signaling. Many treatment forms of prostate cancer are concentrating on inhibiting this signaling pathway. Furthermore expression of androgen receptors is increased in prostate cancer tissue compared to healthy tissue. These factors corroborate that androgen receptor is a good candidate for targeting and imaging prostate cancer. With positron emission tomography tracers it is possible to quantitatively detect receptors in vivo. Selective androgen receptor modulators are class of drug molecules that alter androgen receptor activity. They have high affinity to androgen receptor. The aim of this master's thesis was to produce a fluorine-18 and/or iodine-131 labelled selective androgen receptor modulator derivative that could be used for imaging androgen receptor lesions in metastatic prostate cancer. Two different selective androgen receptor modulators were investigated. The second one, a 4-(pyrrolidin-1-yl) benzonitrile derivative was labelled successfully with iodine-131. Its binding to androgen receptor was tentatively shown with LnCapAR cell line. The radiolabelled compound showed binding to androgen receptor with IC50 value of 0.1903 nM.

The opening segments give a summary of the history of catalysis in general and of frustrated Lewis pairs in particular, where both intra- and intermolecular types are discussed. In addition, the essences of the mechanisms of action of frustrated Lewis pairs are discussed, covering electric field, electron transfer and radical-type mechanisms. There is also a discussion on the activity of frustrated Lewis pairs towards dehydrogenation reactions, in which lies the main scope of this thesis. The background and intended parameters of the experimental aspects of this work are initially defined in the thesis scope, along with the practical considerations concerning the reagents, equipment, and special conditions for synthetic procedures also detailed here. The intention was to attempt to elucidate the extent of the impact of different factors, in this case solvent, Lewis acidity, Lewis basicity, and irradiation by blue LED, on dehydrogenation of various N-substituted pyrrolidine substrates. The subsequent section describes the synthetic procedures used for attempted syntheses of the amino-borane ligands. Not all syntheses of the desired ligands were successful, but there was enough success and enough pre-generated material to proceed to the next stage. Due to use of blue LED causing various potential radical side reactions, it was thought appropriate to describe the behaviour of both the sample and substrate blanks under irradiation, as well as the intended reactions during the screening process. Screening provided preliminary data on reaction determining factors, such as solvent, Lewis acidity of the catalyst, and substrate structure. Despite the relative difficulty and time-consuming nature of the catalyst syntheses, some interesting new modes of reactivity appear to be accessible, which may be worth investigating more in the future.

In this thesis, synthesis and solution properties of the polyampholyte poly(acrylic acid)-b-poly[(vinylbenzyl)trimethylammonium chloride], PAA-PVBTMA-Cl, were investigated in aqueous solutions. First, the diblock copolymer was synthesized via RAFT polymerization where poly(acrylic acid), PAA was used as a chain transfer agent (CTA). In addition, the homopolymer poly[(vinylbenzyl)trimethylammonium chloride], PVBTMA-Cl, was synthesized via RAFT polymerization to compare the solution properties with the block copolymer. Molar masses of the polymers were determined using several methods such as NMR, UV-Vis spectroscopy and SEC. The experimental molar masses were close to theoretical values and block ratio in diblock copolymer from NMR was 30% of AA and 70% of VBTMA-Cl. Furthermore, the solution properties of the polyampholyte were studied under external stimuli such as pH and temperature. UCST type of behaviour was observed for aqueous PAA-PVBTMA-Cl solutions when the hydrophobic trifluoromethanesulfonate (OTf) anion was introduced. In addition, self-assembly of the diblock copolymer was confirmed by zeta potential measurements in different pH conditions. The expected reverse of the micelle structure with changing pH was not observed. However, aqueous PAA-PVBTMA-Cl showed UCST behaviour and micellization induced by the hydrophobic counterion.

It is quite rare to find 6-substituted pyrimidines in nature due to the difficulty involved in directly introducing a substituent to the 6-position whereas other synthetic analogues of naturally occurring nucleosides like 5-substituted derivatives are more common. The aim was to synthesize 3',5'-O,O-bis(tert-butyldimethylsilyl)-6-phenyl-2'-deoxyuridine by carrying out a direct nucleophilic substitution of 3',5'-O,O-bis(tert-butyldimethylsilyl)-6-cyano-2'-deoxyuridine with the Grignard reagent: phenyl magnesium bromide in the presence of zinc (II) chloride catalyst. The first step was silylation of commercially available 2'-deoxyuridine and subsequent bromination at the 5-position to give 3',5'-O,O-bis(tert-butyldimethylsilyl)-5-bromo-2'-deoxyuridine. This was reacted with the nucleophile KCN to yield a product with the cyano substitute at the 6-position via intramolecular nucleophilic substitution. The final step was to introduce an aryl substituent to the 6-position to yield the target molecule.