Phenolics of the Inner Bark of Silver Birch: Characterization and Intraspecific Variation

This thesis describes work related to the in-depth characterization of the phenolic compounds of silver birch (Betula pendula) inner bark. Phenolic compounds are the most ubiquitous class of plant secondary compounds. The unifying feature of this structurally diverse group is an aromatic ring containing at least one hydroxyl group. Due to the structural diversity, phenolics have various roles in the plant defense against biotic and abiotic stresses. In addition, they can confer several health-promoting properties to humans. Furthermore, the structural diversity of this class of compounds causes challenges for their analysis. The study species in the present work, silver birch, is economically the most important hard wood species in northern Europe. Its inner bark contains a high level of phenolic compounds and it has shown one of the strongest antioxidant activities among 92 Finnish plant materials. The literature review surveys the diversity and organ specific distribution of phenolic compounds in silver birch as well as the proposed ecological functions of phenolic compounds in nature. In addition, the basis for the characterization of phenolics by mass spectrometry (MS), nuclear magnetic resonance spectroscopy (NMR), and circular dichroism spectroscopy (CD) are reviewed. The objective of the experimental work was to extract, purify, characterize, and quantify the inner bark phenolic compounds. Overall 36 compounds were characterized by MS and ultraviolet spectroscopy (UV). 24 compounds were isolated and their structures confirmed by NMR and CD spectroscopy. Five novel natural compounds were identified. Special emphasis was placed on the establishment of a method for the characterization of proanthocyanidins (PAs). Hydrophilic interaction liquid chromatography (HILIC) was utilized because of its high resolution power and predictable elution order of oligomeric and polymeric PAs according to an increasing degree of polymerization. The combination of HILIC and high-resolution MS detection allowed the identification of procyanidin (PC) polymers up to the degree of polymerization of 22. In addition, a series of oligomeric and polymeric PC monoxylosides were observed for the first time in nature. Season and genotype influenced the quantities of the main inner bark phenolics, yet qualitative differences were not observed. However, manual wounding of the inner bark induced the production of ellagitannins (ETs) in the wounded tissues, i.e. callus. Since ETs were not detected in the intact inner bark, this finding may reflect the capacity of silver birch to exploit ellagitannins in its defense.

Customer Research on a Group of European Book Publishers: Trends, Modes of Operation and Decision-Making Processes

Työn päätarkoitus oli tuottaa Stora Enson käyttöön tietoa kirjakustantajista, yhdestä yrityksen asiakassegmentistä. Yritys oli kiinnostunut useista asioista, jotka koskivat asiakkaita ja heidän mielipiteitään. Tarkoitus on, että Stora Enso voi käyttää tutkimuksella koottua tietoa oman toimintansa suunnittelun tukena. Kerätty sekundääritieto esittelee eurooppalaisen kirjakustantamisen nykytilaa ja tulevaisuutta sekä teorioita, jotka tukevat tutkittuja aihealueita. Primääritieto kerättiin henkilökohtaisilla haastatteluilla. Otanta koostui kymmenestä kirjakustantajasta, jotka toimivat Suomessa sekä Stora Enson päämarkkina-alueilla. Tutkimus tarjoaa päivitetyn kuvauksen kirjakustantamisesta. Haastateltavien mielipiteet alan trendeistä olivat yhteneviä yleisen mielipiteen kanssa, eikä suuria mielipide-eroavaisuuksia havaittu. Kustantajien toimintatapoja ja päätöksentekoprosesseja voidaan kuvata monimutkaisiksi, koska useat asiat vaikuttavat kirjan syntyyn ja paperin ostoprosessiin. Lisäksi tutkimus esittelee haastateltavien mielipiteitä paperin merkityksestä heidän liiketoiminnassaan.

Stabilization of the ionic form of weak acid cation exchange resins

Weak acid cation exchange (WAC) resins are used in the chromatographic separation of betaine from vinasse, a by-product of sugar industry. The ionic form of the resin determines the elution time of betaine. When a WAC-resin is in hydrogen form, the retention time of betaine is the longest and betaine elutes as the last component of vi-nasse from the chromatographic column. If the feed solution contains salts and its pH is not acidic enough to keep the resin undissociated, the ionic form of the hydrogen form resin starts to alter. Vinasse contains salts and its pH is around 5, it also contains weak acids. To keep the metal ion content (Na/H ratio) of the resin low enough to ensure successful separation of betaine, acid has to be added to either eluent (water) or vinasse. The aim of the present work was to examine by laboratory experiments which option requires less acid. Also the retention mechanism of betaine was investigated by measuring retention volumes of acetic acid and choline in different Na/H ratios of the resin. It was found that the resulting ionic form of the resin is the same regardless of whether the regeneration acid is added to the eluent or the feed solution (vinasse). Be-sides the salt concentration and the pH of vinasse, also the concentration of weak acids in the feed affects the resulting ionic form of the resin. The more buffering capacity vinasse has, the more acid is required to keep the ionic form of the resin desired. Vinasse was found to be quite strong buffer solution, which means relatively high amounts of acid are required to prevent the Na/H ratio from increasing too much. It is known that the retention volume of betaine decreases significantly, when the Na/H ratio increases. This is assumed to occur, because the amount of hydrogen bonds between the carboxylic groups of betaine and the resin decreases. Same behavior was not found with acetic acid. Choline has the same molecular structure as betaine, but instead of carboxylic group it has hydroxide group. The retention volume of choline increased as the Na/H ratio of the resin increased, because of the ion exchange reaction between choline cation and dissociated carboxylic group of the resin. Since the retention behavior of choline on the resin is opposite to the behavior of be-taine, the strong affinity of betaine towards hydrogen form WAC-resin has to be based on its carboxylic group. It is probable that the quaternary ammonium groups also affect the behavior of the carboxylic groups of betaine, causing them to form hydrogen bonds with the carboxylic groups of the resin.

Immobilization of Burkholderia cepacia Lipase: Kinetic Resolution in Organic Solvents, Ionic Liquids and in Their Mixtures

Immobilization of Burkholderia cepacia Lipase: Kinetic Resolution in Organic Solvents, Ionic Liquids and in Their Mixtures Biocatalysis opens the door to green and sustainable processes in synthetic chemistry allowing the preparation of single enantiomers, since the enzymes are chiral and accordingly able to catalyze chemical reactions under mild conditions. Immobilization of enzymes enhances process robustness, often stabilizes and activates the enzyme, and enables reuse of the same enzyme preparation in multiple cycles. Although hundreds of variations of immobilization methods exist, there is no universal method to yield the highly active, selective and stable enzyme catalysts. Therefore, new methods need to be developed to obtain suitable catalysts for different substrates and reaction environments. Lipases are the most widely used enzymes in synthetic organic chemistry. The literature part together with the experimental part of this thesis discusses of the effects of immobilization methods mostly used to enhance lipase activity, stability and enantioselectivity. Moreover, the use of lipases in the kinetic resolution of secondary alcohols in organic solvents and in ionic liquids is discussed. The experimental work consists of the studies of immobilization of Burkholderia cepacia lipase (lipase PS) using three different methods: encapsulation in sol-gels, cross-linked enzyme aggregates (CLEAs) and supported ionic liquids enzyme catalysts (SILEs). In addition, adsorption of lipase PS on celite was studied to compare the results obtained with sol-gels, CLEAs and SILEs. The effects of immobilization on enzyme activity, enantioselectivity and hydrolysis side reactions were studied in kinetic resolution of three secondary alcohols in organic solvents, in ionic liquids (ILs), and in their mixtures. Lipase PS sol-gels were shown to be active and stable catalysts in organic solvents and solvent:IL mixtures. CLEAs and SILEs were highly active and enantioselective in organic solvents. Sol-gels and SILEs were reusable in several cycles. Hydrolysis side reaction was suppressed in the presence of sol-gels and CLEAs.

Understanding and improving quality of secondary school education : conceptions among teachers in Tanzania

Temat för studien handlar om gymnasielärares uppfattningar om kvalitet och om hur kvalitet kan utvecklas i gymnasieutbildningen in Tanzania. Studien är till sin karaktär kvalitativ och består av utprövade semistrukturerade intervjuer med sammanlagt trettio lärare som arbetar i fyra gymnasieskolor både i urbana och rurala miljöer. Lärarna har varierande arbetserfarenhet och undervisar i olika ämnen. Huvudfokus har gällt identifieringen av variationer i lärares uppfattningar om kvalitet. På basen av två forskningsfrågor avslöjar analysen uppfattningar av hur lärare förstår och önskar utveckla kvaliteten på gymnasieutbildningen. Resultaten visar att lärare förstår kvaliteten på utbildningen i sina skolor som försök att möta skolans och samhällets mål, som individuella prestationer och förmågor som att inneha kompetenser och som att möta utmaningar inom utbildning, Identifierade uppfattningar var baserade på lärarnas personliga kunskap, arbetsmiljön och varierande omständigheter som rådde i deras skolor. Uppfattningar om en förbättring av kvaliteten i gymnasieutbildningen innefattade utveckling av lärares motivation, skolmiljön, arbetet i klassrum, kvaliteten på lärares kunskaper och färdigheter och undervisningsmaterial. Ambitionen bakom studien ar att erbjuda en plattform för strategier för att förbättra kvaliteten på gymnasieutbildningen. Resultaten strävar till att ge en fördjupad insikt i uppfattningar hos en utvald grupp av lärare som arbetar under samma villkor inom gymnasieskolor I Tanzania. Av den här anledningen är den genererade kunskapen därför relevant för att belysa lärares uppfattningar även utanför den studerade gruppen av respondenter.

Towards optimal fractionation of lignocellulosic biomass using switchable ionic liquids

En ny familj av reversibla (switchable) joniska vätskor (SIL) innehållande 1,8-diazobicyklo-[5.4.0]-undek-7-en (DBU), en molekyl innehållande en eller flera hydroxyl- grupper (t.ex. glycerol) och en sur gas (CO2, SO2) syntetiserades via en enkel procedur samt karakteriserades. [DBU][karbonat] eller [sulfonat] bildades ur en respektive icke-jonisk blandning av en molekylär, organisk polyol (eller ennan molekyl innehållande en OH-grupp) och en amidinbas under bubblandet av en sur gas. Därtill kunde den joniska vätskan omvandlas tillbaka till sina beståndsdelar med hjälp av att upphetta och/eller bubbla en inert gas såsom kväve genom vätskan. SIL- strukturerna kartlades med bl.a. NMR- och FTIR- spektroskopi. Omvandlingen från lågpolära (molekylära) vätskor till högpolära joniska vätskor (SIL) bekräftades även genom att observera förändringar i deras fysikaliska egenskaper, såsom viskositet och färg. Nedbrytningstemperaturerna hos SILs bestämdes med hjälp av termogravimetrisk analys (TGA) som antydde att nedbrytningstemperaturen hos de syntetiserade föreningarna log mellan 50 och 200oC. De nya joniska vätskorna uppvisade högre nedbrytningstemperaturer jämfört med i litteraturen tidigare förekommande exempel och kunde därför tillämpas på flera ändamål. Därtill, reversibla (switchable) joniska vätskor uppbyggda av bl.a. alkoholer, antingen hexanol eller butanol, och CO2 samt en amidin (DBU) användes vid upplösning och fraktionering av ved. Joniska vätskor syntetiserade ur glycerol och sura gaser tillsammans med amidiner användes även för fraktionering av andra lignocellulosor såsom färsk björk (Betula pendula). Björkflis utsattes för behandling, för en period på en till fem dagar vid 100oC och under atmosfäriskt tryck. Alla syntetiserade joniska vätskor visade sig vara relativt neutrala i avseende på upplösning och avlägsnandet av lignin. Slutligen, optimala fraktioneringprocessbetingelser för ved med reversibla joniska vätskor kartlades. Fraktionering av vedbiomassa med dessa joniska vätskor uppvisade sig att vara en selektiv och effektiv metod för extraktion av olika komponenter från lignocellulosa. Den olösta fraktionen hos en vedflis, närmast cellulosa, fibrillerades. -------------------------------------------------------------------------------------------------------------------- Tässä työssä kehitettiin perhe uuden tyyppisiä, reversiibeleitä (switchable) ioninesteitä ( SIL ) joka koostuvat orgaanisesta super-emäksestä kuten 1,8- diatsabisyklo [ 5.4.0] undek- 7-eeni (DBU ) ja yhden tai useampia hydroksyyliryhmiä sisältältävästä molekyylistä (esim. glyseroli) ja happamasta kaasusta (CO2 , SO2) yksinkertaisen menetelmän avulla. [DBU] [ karbonaatti] tai [sulfonaatti] syntetisoitiin kunkin lähtöaineen seoksista kuplittamalla seosta happamalla kaasulla jolloin eksoterminen reaktio tapahtui ja ioninen neste syntyi. Ioniset nesteet voitiin palauttaa takaisin lähtöaineseokseksi kuumentamalla ja/tai kuplittamalla neutraalia kaasua (esim. typpi) seoksen läpi. SIL rakenteet määritettiin ja niiden ominaisuudet kartoitettiin eri menetelmillä, mukaan lukien NMR- ja FTIR -spektroskopia. Ionisen, korkeapoläärisen nesteen syntyminen todennettiin myös viskositeettimittauksilla ja värinmuutoksilla käyttäen hyväksi polariteetti-indikaattoria (Nile red). Myös hajoamislämpötilat määritettiin termogravimetrisellä analyysillä (TGA) ja todettiin että syntetisoitujen yhdisteiden hajoamislämpötila oli välillä 50 ja 200oC . Näiden uusien reversiibeleiden ioninesteiden hajoamisämpötilat olivat korkeammat verrattuna kirjallisuudessa aikaisemmin mainittuihin esimerkkeihin joten niitä voidaan soveltaa useisiin tarkoituksiin. Myös ioninesteitä jotka sisälsivät primäärejä alkoholeja rakennusaineina syntetisoitiin ja hyödynnettiin puun fraktioinnissa. Männyn ja kuusen lisäksi tuoreita koivulastuja onnistuttiin fraktioimaan miedoissa olosuhteissa. Kaikkien syntetisoitujen ioninesteiden todettiin olevan suhteellisen neutraaleja ligniinin liuotuksen suhteen. Vielä, optimaaliset fraktiointiolosuhteet määritettiin ryhmälle reversiibeleitä ioninesteitä ja näiden uudenlaisten ioninesteiden todettiin olevan tehokkaita puun ja muiden lignoselluloosien eri fraktioiden liuotuksessa. Liukenematon osa puulastua joka oli lähinnä selluloosaa fibrilloitui.

Studies in selectivity of lipases in preparation of cyanohydrins, sugar conjugates and secondary alcohols

Biocatalysis can be applied in organic synthetic chemistry to counter challenges posed by increased demands towards chemo-, regio- and stereoselectivity, not forgetting the need for greener chemistry. During the last 30 years, biocatalysis with the use of enzymes as chiral catalysts has become more common in chemistry laboratories and industrial processes. In this thesis, the use of lipases as versatile biocatalysts in the acylation of alcohols is examined both in the light of literature examples and four original publications. In the first part of the work presented in this thesis lipases were utilized in two examples concerning secondary alcohols. First, the kinetic resolution of heterocyclic aromatic secondary alcohols through transesterification was thoroughly examined including the studies of competing hydrolysis and esterification reactions. In another example, lipases were utilized in the formation of a dynamic systemic resolution (DSR) process which in turn was used as a developmental tool in the optimization of the dynamic kinetic resolution (DKR) of five heterocyclic aromatic cyanohydrins in one pot for the preparation of cyanohydrin esters as single enantiomers. In the second part of the work, the regio- and stereoselectivity of lipases was used to form sugar conjugates of glyceric and β-amino acids. The primary hydroxyl groups of methyl α-D-galacto-, -gluco- and -mannopyranosides were now acylated trough lipasecatalyzed transesterification and enantioselective lipase-catalyzed ring-opening of β- lactams, respectively.