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  • Rahikainen, Jenni (Helsingin yliopisto, 2013)
    Lignin, a major non-carbohydrate polymer in lignocellulosic plant biomass, restricts the action of hydrolytic enzymes in the enzymatic hydrolysis of lignocellulosic feedstocks. Non-productive enzyme adsorption onto lignin is a major inhibitory mechanism, which results in decreased hydrolysis rates and yields and difficulties in enzyme recycling. The mechanisms of non-productive binding are poorly understood; therefore, in this thesis, enzyme-lignin interactions were studied using isolated lignins from steam pretreated and non-treated spruce and wheat straw as well as monocomponent cellulases with different modular structures and temperature stabilities. The origin of the isolated lignin had an undisputable effect on non-productive binding. Ultrathin lignin films, prepared from steam pretreated and non-treated lignin preparations, were employed in QCM adsorption studies in which Trichoderma reesei Cel7A (TrCel7A) was found to bind more onto lignin isolated from steam pretreated biomass than onto lignin isolated from non-treated lignocellulosic biomass. Botanical differences in lignin chemistry had only a minor effect on nonproductive binding when enzyme binding to non-treated wheat straw and spruce lignin was compared. Increase in temperature was found to increase the inhibitory effect arising from non-productive enzyme binding to lignin. Different enzymes were shown to have a characteristic temperature at which the inhibition emerged. Thermostable enzymes were the most lignin-tolerant at high temperatures, suggesting that in addition to the surface properties of an enzyme, non-productive binding onto lignin may be influenced by stability of the enzyme structure. In addition, for lignin-bound T. reesei cellulases, increase in temperature resulted in loss of catalytic activity and tighter binding, suggesting that at high temperature enzyme binding to lignin was probably coupled to conformational changes in the protein folding. With TrCel7A, carbohydrate-binding module (CBM) was found to increase nonproductive adsorption to lignin. The Talaromyces emersonii Cel7A catalytic module was linked to a CBM from TrCel7A, giving rise to a fusion enzyme TeCel7A-CBM1. Despite a similar CBM, TeCel7A-CBM adsorbed significantly less to lignin than TrCel7A, indicating that the catalytic module (TeCel7A) had a strong contribution to the low binding. Probably, the contribution of CBM or catalytic core module in non-productive binding varies between different enzymes, and the role of the CBM is not always dominant. To date, very little attention has been paid to the role of electrostatic interactions in lignin-binding. In this work, binding of Melanocarpus albomyces Cel45A endoglucanase onto lignin was found to be very dependent on pH, suggesting that electrostatic interactions were involved in the binding. At high pH, significantly less non-productive binding occurred, probably due to increasing electrostatic repulsion between negatively charged enzymes and lignin. Modification of the charged chemical groups in enzymes or lignin may be a viable strategy to reduce nonproductive enzyme binding in the hydrolysis of lignocellulosic substrates.
  • Hiltunen, Miia (Helsingin yliopisto, 2013)
    Cellulose is the most abundant renewable natural polymer, with many attractive physical and chemical properties including hydrophilicity, biodegradability and biocompatibility. However, its effective use as bio-based material is limited due to its insolubility in water and organic solvents, as well as due to difficult processability. The main objective of this research was to utilize the new controlled/living free radical polymerization (CRP) methods in the modifications of various cellulosic materials, yielding new water-soluble cellulose based graft copolymers (cellulose-g-copolymers) with a uniform molecular structures. The recent developments in CRP methods have enabled the tailoring of macromolecules with sophisticated architectures including block, graft and star structures with predetermined molecular weights, terminal functionalities, and narrow molecular weight distributions. Modification by graft copolymerization using CRP methods provides one of the best ways to combine the advantages of both natural cellulose and synthetic polymers and therefore affect the properties of the cellulose derivatives. The cellulose-g-copolymers have various potential applications over a wide range of areas, such as sensor matrices, recognition devices, selective membranes, organic-inorganic complex materials, and bioactive and biocompatible materials. In this study novel water-soluble cellulose-g-copolymers were successfully synthesized via CRP methods (RAFT and ATRP/SET-LRP). In addition to unmodified cellulose (softwood dissolving pulp), cellulose ethers (carboxymethyl cellulose (CMC) and ethyl hydroxyethyl cellulose (EHEC)) were also used as starting materials i.e. as backbones for the cellulose-g-copolymers. Homogeneous reaction conditions were used to confirm as uniform structure of the graft copolymers as possible. The influence of the side chain length and the grafting density on the aqueous solution and thermal properties of the graft copolymers were studied.
  • R. Labafzadeh, Sara (Helsingin yliopisto, 2015)
    Worldwide research is focused on the use of renewable and biodegradable raw materials due to the limited existing quantities of fossil supplies and the environmental degradation caused by global warming. Cellulose, derived from natural resources such as wood, annual plants and microbes, represents the most abundant renewable polymeric material on earth. Due to its low cost and functional versatility, cellulose has been a key feedstock for the production of chemicals with various properties and applications over the past century. It has found a wide range of applications in food, printing, cosmetics, pharmacy, therapeutics, paper making and in the textile industry. This partly crystalline polymer has not yet reached its full application potential due to its essential insolubility in most common solvents. Many investigations focus on the development of novel media for efficient and economically feasible functionalization of cellulose. The chemical modification of cellulose overcomes this obstacle and offers considerable opportunities for preparing cellulose-based polymeric materials. The modification could adjust the properties of the macromolecule for different purposes and meet the environmental requirements by using green reagents and recyclable solvent systems. Synthesis of new cellulose-based polymers and their thorough characterization and increasing the usefulness of cellulose by altering its properties have been of growing research interest for the past few years. The objective of this research was to investigate new paths for the preparation of cellulose-based materials with a variety of structural features to obtain advanced materials suitable for different applications. Most of the research has focused purely on the synthesis of cellulose derivatives in new and economically feasible solvent systems, but it also has general relevance for the material properties of the obtained derivatives. Also, the potential application of synthesized cellulose derivatives as barrier films for packaging was investigated. Highly substituted cellulose esters, carbamates and carbonates were prepared using various recyclable reaction solvents. Biomaterials with the potential for use in the packaging sector should provide high mechanical properties, in addition to good barrier properties for oxygen and water vapour. Some derivatives showed good barrier properties being promising for packaging application.
  • Granström, Mari (Helsingin yliopisto, 2009)
    Even though cellulose is the most abundant polymer on Earth, its utilisation has some limitations regarding its efficient use in the production of bio-based materials. It is quite clear from statistics that only a relatively small fraction of cellulose is used for the production of commodity materials and chemicals. This fact was the driving force in our research into understanding, designing, synthesising and finding new alternative applications for this well-known but underused biomaterial. This thesis focuses on the developing advanced materials and products from cellulose by using novel approaches. The aim of this study was to investigate and explore the versatility of cellulose as a starting material for the synthesis of cellulose-based materials, to introduce new synthetic methods for cellulose modification, and to widen the already existing synthetic approaches. Due to the insolubility of cellulose in organic solvents and in water, ionic liquids were applied extensively as the reaction media in the modification reactions. Cellulose derivatives were designed and fine-tuned to obtain desired properties. This was done by altering the inherent hydrogen bond network by introducing different substituents. These substituents either prevented spontaneous formation of hydrogen bonding completely or created new interactions between the cellulose chains. This enabled spontaneous self-assembly leading to supramolecular structures. It was also demonstrated that the material properties of cellulose can be modified even those molecules with a low degree of substitution when highly hydrophobic films and aerogels were prepared from fatty acid derivatives of nanocellulose. Development towards advanced cellulose-based materials was demostrated by synthesising chlorophyllcellulose derivatives that showed potential in photocurrent generation systems. In addition, liquid crystalline cellulose derivatives prepared in this study, showed to function as UV-absorbers in paper.
  • Kuutti, Lauri (Helsingin yliopisto, 2013)
    Despite the similarity of their structural basic units, cellulose- and starch-based materials behave differently in many industrial applications. In this thesis, the structure and properties of these polysaccharides and their selected derivatives were studied by means of five comprehensive examples. In the first investigation, highly crystalline cellulose was identified from Valonia macrophysa vesicles by atomic force microscopy. The role of water as a possible modifier on the surface of cellulose was found to be very important. The monoclinic phases were found on the cellulose surfaces with a lateral resolution of about 4 Å, indicating that water molecules cannot penetrate and thus disturb the surface structure of monoclinic cellulose. On the other hand, the absence of triclinic phases was explained by the used measuring geometry without liquid cell. The ageing of metastable oat and barley thermoplastic starch films was followed by frictional imaging. As a consequence of the ageing, the films lose some of their mechanical properties. In the oat films, glycerol used as a plasticiser diffused from the starch-glycerol-water matrix to the surface of thermoplastic starch, resulting in areas with low friction. In the case of barley starch films, the ageing first resulted in short range reorientation of polymers and finally slow crystallization of amylopectin branches. Solution precipitation techniques were applied to produce ideally spherical starch ester particles (with a diameter about half the wavelength of visible light), suitable for fillers in paper coatings in the third study. Particles assume their shape and size spontaneously when solvated starch polymer is mixed with non-solvent, due to the free mobility of the modified starch chains. Starch pigment has improved affinity to paper surface and it can be used as such or mixed with other pigments to enhance the optical or printing properties of paper. Starch-based pigmenting materials with improved optical performance were prepared in the laboratory by the complexation approach. Analytical results indicated that the complexation of carboxymethyl starch and inorganics strongly depends on the carboxymethyl group in the starch-based hybrid pigmented materials. The formed insoluble hybrids were mostly amorphous and the crystalline contribution of the inorganic component was not evident. The resulting precipitates exhibited composite structures. Finally, three starch-based and two cellulose-based polymers were selected for flocculation and filtration tests. In shearless dewatering conditions, the retention and dewatering properties of the starch-based polymers were similar to those of commercial polyacrylamide-based polymers. The flow studies in higher shear conditions showed that with the studied dosages the starch-based polymers could not reach the flocculation levels needed to maintain sufficient retention properties. The performance of the cellulose-based polymers as flocculating agents was less efficient. The reasons for the more limited performance of the polysaccharide-based flocculants were too low molecular weight and the charge density distribution. Better understanding of how to improve the hydrodynamic properties of bio-based polymers will be essential when planning new bio-based flocculants. The deeper understanding of the relationships between the desired structures and properties of polysaccharides helps to utilize them more effectively. In this way it is possible to obtain better bio-based and environmentally sustainable products in the competition with the current products based on conventional petrochemistry.
  • Holopainen, Juha (Helsingin yliopisto, 2001)
  • Linko-Parvinen, Anna-Maria (Helsingin yliopisto, 2006)
    Several studies link the consumption of whole-grain products to a lowered risk of chronic diseases, such as certain types of cancer, type II diabetes, and cardiovascular diseases. However, the final conclusions of the exact protective mechanisms remain unclear, partly due to a lack of a suitable biomarker for the whole-grain cereals intake. Alkylresorcinols (AR) are phenolic lipids abundant in the outer parts of wheat and rye grains usually with homologues of C15:0- C25:0 alkyl chains, and are suggested to function as whole-grain biomarkers. Mammalian lignan enterolactone has also previously been studied as a potential whole-grain biomarker. In the present work a quantified gas chromatography-mass spectrometry method for the analysis of AR in plasma, erythrocytes, and lipoproteins was developed. The method was used to determine human and pig plasma AR concentrations after the intake of whole-grain wheat and rye products compared to low-fibre wheat bread diets to assess the usability of AR as biomarkers of whole-grain intake. AR plasma concentrations were compared to serum ENL concentrations. AR absorption and elimination kinetics were investigated in a pig model. AR occurrence in human erythrocyte membranes and plasma lipoproteins were determined, and the distribution of AR in blood was evaluated. Plasma AR seem to be absorbed via the lymphatic system from the small intestine, like many other lipophilic compounds. Their apparent elimination half-life is relatively short and is similar to that of tocopherols, which have a similar chemical structure. Plasma AR concentrations increased significantly after a one- to eight-week intake of whole-grain wheat and further on with whole-grain rye bread. The concentrations were also higher after habitual Finnish diet compared to diet with low-fibre bread. Inter-individual variation after a one-week intake of the same amount of bread was high, but the mean plasma AR concentrations increased with increasing AR intake. AR are incorporated into erythrocyte membranes and plasma lipoproteins, and VLDL and HDL were the main AR carriers in human plasma. Based on these studies, plasma AR could function as specific biomarkers of dietary whole-grain products. AR are exclusively found in whole-grains and are more suitable as specific biomarkers of whole-grain intake than previously investigated mammalian lignan enterolactone, that is formed from several plants other than cereals in the diet. Plasma AR C17:0/C21:0 -ratio could distinguish whether whole-grain products in the diet are mainly wheat or rye. AR could be used in epidemiological studies to determine whole-grain intake and to better assess the role of whole-grains in disease prevention.
  • Hannikainen, Heikki (2013)
    Background and purpose: Cerebral venous thrombosis (CVT) is a rare, but serious disease, commonly occurring in young to middle‐aged women. It is not yet known whether sinus size and shape confers a risk for thrombosis and whether clot size is correlated with recanalization rates, and because there is no established method for measuring sinus or clot size, we decided to develop one. Patients and methods: CVT patients with 3‐D magnetic resonance imaging done early for diagnosis and follow‐up imaging around 6 months or later were recruited. Age and sexmatched (1:2) control subjects were patients with various benign headache problems who underwent 3D MRI for excluding CVT or other acute structural disease. All major sinuses were measured in size (area and diameter). All detected clots underwent similar measurement (volume, area and length). Measurements were done with Osirix‐software. Results: 25 CVT patients (17 females and 8 males) and 50 control subjects were measured. Volume of the thrombus was either dissolved or reduced in all except one case. Sinus area in CVT patients in follow‐up imaging was slightly smaller compared to healthy subjects ( P=0.052‐0.170). Thrombus volumes were bigger (P=0.009) but also dissolved more effectively in women, with no difference in sex‐groups in follow‐up imaging. Residual clot volume was bigger in older patients (P=0.007). Other factors did not strongly correlate with thrombus volume. Measurement reproducibility with two individual investigators was good, with best interrater correlation of over 95% in volume measures. Conclusions: This is the first attempt in establishing a volumetric measurement of cerebral sinuses and clots. The methodology may help in estimating probability of recanalization and in trials with interventions such as local thrombolysis and thrombectomy.
  • Hannikainen, Heikki (2014)
    Background and purpose: Cerebral venous thrombosis (CVT) is a rare, but serious disease, commonly occurring in young to middle‐aged women. It is not yet known whether sinus size and shape confers a risk for thrombosis and whether clot size is correlated with recanalization rates, and because there is no established method for measuring sinus or clot size, we decided to develop one. Patients and methods: CVT patients with 3‐D magnetic resonance imaging done early for diagnosis and follow‐up imaging around 6 months or later were recruited. Age and sexmatched (1:2) control subjects were patients with various benign headache problems who underwent 3D MRI for excluding CVT or other acute structural disease. All major sinuses were measured in size (area and diameter). All detected clots underwent similar measurement (volume, area and length). Measurements were done with Osirix‐software. Results: 25 CVT patients (17 females and 8 males) and 50 control subjects were measured. Volume of the thrombus was either dissolved or reduced in all except one case. Sinus area in CVT patients in follow‐up imaging was slightly smaller compared to healthy subjects ( P=0.052‐0.170). Thrombus volumes were bigger (P=0.009) but also dissolved more effectively in women, with no difference in sex‐groups in follow‐up imaging. Residual clot volume was bigger in older patients (P=0.007). Other factors did not strongly correlate with thrombus volume. Measurement reproducibility with two individual investigators was good, with best interrater correlation of over 95% in volume measures. Conclusions: This is the first attempt in establishing a volumetric measurement of cerebral sinuses and clots. The methodology may help in estimating probability of recanalization and in trials with interventions such as local thrombolysis and thrombectomy.
  • Nikkilä, Heikki (Helsingin yliopisto, 2000)
  • Constantin, Camelia (Helsingin yliopisto, 2008)
    B. cereus is one of the most frequent occurring bacteria in foods . It produces several heat-labile enterotoxins and one stable non-protein toxin, cereulide (emetic), which may be pre-formed in food. Cereulide is a heat stable peptide whose structure and mechanism of action were in the past decade elucidated. Until this work, the detection of cereulide was done by biological assays. With my mentors, I developed the first quantitative chemical assay for cereulide. The assay is based on liquid chromatography (HPLC) combined with ion trap mass spectrometry and the calibration is done with valinomycin and purified cereulide. To detect and quantitate valinomycin and cereulide, their [NH4+] adducts, m/z 1128.9 and m/z 1171 respectively, were used. This was a breakthrough in the cereulide research and became a very powerful tool of investigation. This tool made it possible to prove for the first time that the toxin produced by B. cereus in heat-treated food caused human illness. Until this thesis work (Paper II), cereulide producing B. cereus strains were believed to represent a homogenous group of clonal strains. The cereulide producing strains investigated in those studies originated mostly from food poisoning incidents. We used strains of many origins and analyzed them using a polyphasic approach. We found that the cereulide producing B. cereus strains are genetically and biologically more diverse than assumed in earlier studies. The strains diverge in the adenylate kinase (adk) gene (two sequence types), in ribopatterns obtained with EcoRI and PvuII (three patterns), tyrosin decomposition, haemolysis and lecithine hydrolysis (two phenotypes). Our study was the first demonstration of diversity within the cereulide producing strains of B. cereus. To manage the risk for cereulide production in food, understanding is needed on factors that may upregulate cereulide production in a given food matrix and the environmental factors affecting it. As a contribution towards this direction, we adjusted the growth environment and measured the cereulide production by strains selected for diversity. The temperature range where cereulide is produced was narrower than that for growth for most of the producer strains. Most cereulide was by most strains produced at room temperature (20 - 23ºC). Exceptions to this were two faecal isolates which produced the same amount of cereulide from 23 ºC up until 39ºC. We also found that at 37º C the choice of growth media for cereulide production differed from that at the room temperature. The food composition and temperature may thus be a key for understanding cereulide production in foods as well as in the gut. We investigated the contents of [K+], [Na+] and amino acids of six growth media. Statistical evaluation indicated a significant positive correlation between the ratio [K+]:[Na+] and the production of cereulide, but only when the concentrations of glycine and [Na+] were constant. Of the amino acids only glycine correlated positively with high cereulide production. Glycine is used worldwide as food additive (E 640), flavor modifier, humectant, acidity regulator, and is permitted in the European Union countries, with no regulatory quantitative limitation, in most types of foods. B. subtilis group members are endospore-forming bacteria ubiquitous in the environment, similar to B. cereus in this respect. Bacillus species other than B. cereus have only sporadically been identified as causative agents of food-borne illnesses. We found (Paper IV) that food-borne isolates of B. subtilis and B. mojavensis produced amylosin. It is possible that amylosin was the agent responsible for the food-borne illness, since no other toxic substance was found in the strains. This is the first report on amylosin production by strains isolated from food. We found that the temperature requirement for amylosin production was higher for the B. subtilis strain F 2564/96, a mesophilic producer, than for B. mojavensis strains eela 2293 and B 31, psychrotolerant producers. We also found that an atmosphere with low oxygen did not prevent the production of amylosin. Ready-to-eat foods packaged in micro-aerophilic atmosphere and/or stored at temperatures above 10 °C, may thus pose a risk when toxigenic strains of B. subtilis or B. mojavensis are present.
  • Honkasalo, Julia (Helsingin yliopisto, 2006)
    Epistemological foundationalism has for centuries attempted to unify all scientific inquiry into the context of one grand science, the first philosophy. One of the most important tasks of this tradition has been to ground all knowledge on absolutely certain foundations. In this master s thesis I ask the following question: To what extent and under what conditions is it possible to achieve absolute certainty in the sense of the attempts of Cartesian foundationalism? By examining how the 20th century philosophers, Edmund Husserl (1859-1938), Hannah Arendt (1906-1975) and Maurice Merleau-Ponty (1908-1961) interpret the epistemological methodology of René Descartes, I claim that the Cartesian achievement of absolute certainty rests on the implicit presupposition of an epistemologically prior form of faith in the world and trust (pistis) in other conscious beings. I show that knowledge is possible only within the context of a common world that is inhabited by several conscious beings that share a common linguistic system. This threefold element is shown to be the bedrock condition for any kind of philosophical inquiry. The main literature sources for this thesis are The Life of the Mind by Hannah Arendt, Le Visible et l invisible by Maurice Merleau-Ponty, Meditationes de Prima Philosophiae by René Descartes and Erfahrung und Urteil by Edmund Husserl.
  • Kirjavainen, Mirja (Helsingin yliopisto, 2010)
    Class II division 1 malocclusion occurs in 3.5 to 13 percent of 7 12 year-old children. It is the most common reason for orthodontic treatment in Finland. Correction is most commonly performed using headgear treatment. The aim of this study was to investigate the effects of cervical headgear treatment on dentition, facial skeletal and soft tissue growth, and upper airway structure, in children. 65 schoolchildren, 36 boys and 29 girls were studied. At the onset of treatment a mean age was 9.3 (range 6.6 12.4) years. All the children were consequently referred to an orthodontist because of Class II division 1 malocclusion. The included children had protrusive maxilla and an overjet of more than 2mm (3 to 11 mm). The children were treated with a Kloehn-type cervical headgear as the only appliance until Class I first molar relationships were achieved. The essential features of the headgear were cervical strong pulling forces, a long upward bent outer bow, and an expanded inner bow. Dental casts and lateral and posteroanterior cephalograms were taken before and after the treatment. The results were compared to a historical, cross-sectional Finnish cohort or to historical, age- and sex-matched normal Class I controls. The Class I first molar relationships were achieved in all the treated children. The mean treatment time was 1.7 (range 0.3-3.1) years. Phase 2 treatments were needed in 52% of the children, most often because of excess overjet or overbite. The treatment decreased maxillary protrusion by inhibiting alveolar forward growth, while the rest of the maxilla and mandible followed normal growth. The palate rotated anteriorly downward. The expansion of the inner bow of the headgear induced widening of the maxilla, nasal cavity, and the upper and lower dental arches. Class II malocclusion was associated with narrower oro- and hypopharyngeal space than in the Class I normal controls. The treatment increased the retropalatal airway space, while the rest of the airway remained unaffected. The facial profile improved esthetically, while the facial convexity decreased. Facial soft tissues masked the facial skeletal convexity, and the soft tissue changes were smaller than skeletal changes. In conclusion, the headgear treatment with the expanded inner bow may be used as an easy and simple method for Class II correction in growing children.
  • Metso, Tiina (Helsingin yliopisto, 2013)
    Cervicocerebral artery dissection (CeAD) is one of the leading causes of ischemic stroke in the young and middle-aged adults. The pathophysiology of CeAD is poorly understood. CeAD patients probably have a constitutional, partly genetic weakness of the vessel wall, which predisposes to tears in the connective tissue within the vascular wall in occurrence of environmental triggers of the disease, such as acute infection, migraine, or minor trauma. For this thesis project, we collected a register of all consecutive CeAD patients treated at the Helsinki University Central Hospital, Finland, between 1994 and 2008. In the first part of the thesis, we studied 103 patients with intracranial artery dissections (IAD). IADs could be divided into 2 distinct groups: i) non-aneurysmatic IADs presenting without subarachnoid hemorrhage that are associated with favorable outcomes and safe anticoagulant therapy, and ii) aneurysmatic IADs, characterized by subarachnoid hemorrhage and poorer prognosis. Secondly, we evaluated characteristics, prognostic factors and vascular risk factors in 301 CeAD patients. We found association of CeAD with male sex, and possible association with smoking and migraine, especially migraine with aura. Stroke severity and recent infection were associated with poorer outcome. The three other publications for the thesis were part of the CADISP project (Cervical Artery Dissection and Ischemic Stroke Patients), an international consortium focusing on research on CeAD. For the clinical part of CADISP, 983 patients with CeAD, 658 patients with ischemic stroke due to causes other than dissection, and 1170 healthy control subjects were included in 8 countries and 18 centers. In the CADISP cohort, vascular risk factors were less frequent in CeAD patients compared with young patients with a non-CeAD ischemic stroke. In comparison with healthy controls, hypercholesterolemia, obesity, and overweight were less frequent in CeAD patients, whereas CeAD patients had more hypertension. This suggests that hypertension may be a risk factor for CeAD. Finally, migraine was more common in CeAD patients with stroke than in patients with ischemic stroke due to a cause other than CeAD. We detected no excess of ischemic strokes, specific arterial distribution or other clinical or prognostic features characteristic to migraineous CeAD patients compared to those without migraine.
  • Zhang, Liangying (1999)
    The recently continuing proliferation of regional Preferential Trade Agreements (PTAs) and the glowing trend of emerging tri-bloc (Europe, America, Asia) raise the concern that the regional trade arrangements may challenge the world trading system embodied in the General Agreement on Tariff and Trade (GATT) and World Trade Organisation (WTO). In response to this background, this thesis reviews both the old and new key theoretical contributions on PTAs. The emphasis is put on the new one, which addresses the direct effect of regional arrangement on multilateral process. Basic international trade theory and policy, terminology and background are provided at the beginning to facilitate reading. While the paper does not attempt to put normative judgement on PTAs, it does call for more effort on multilateral process in the conclusion. Among the old literature, this paper reviews the classical work of Viner. Viner had a doubt on the welfare improvement Customs Union by raising the concept of trade diversion and trade creation. His model implies that unambiguous gain can only be obtained when the partner countries are the sole source of import even in the initial equilibrium. Among the recent literature, this paper reviews the analyses from the viewpoint of 'new political economy' which view trade policy as being determined by lobbying of the concentrated interest groups. Two models, Grossman-Helpman's and Krishna's, are introduced. Grossman-Helpman's small union model, which takes a specific factor model with n+1 goods in a political economy framework, addresses the incentive for the government to conclude a Free Trade Area, and reaches conclusion that free trade agreement could more likely be reached when it affords enhanced protection. Krishna's Cournot oligopoly model uses a similar framework of Grossman and Helpman's, however examines further the direction relation between the regional arrangement and multilateral process besides the incentive, and concludes the trade-diversion incentive and harmful effect of regional trade agreement on multilateral trade liberalisation.
  • Joas, Markus (2014)
    The Finnish forest industries are going through heavy adjustments as especially the western world is moving towards a more digitalized model where the amount of paper and pulp consumed is diminishing. It is obvious that the whole industry is in need for new solutions. These new solutions and innovations can be found from the field of bioenergy. Finland is rich with forest-based raw material which can provide a long-term and local source of energy. In the future this will be of primary importance as the prices of the non-renewable energy sources will climb higher as the deposits of the fossil fuels dry up. The usage of the renewable energy sources are also very important in order to prevent the global climate change and to achieve the goals regulated for Finland in the Kyoto Protocol and the European RES-E directive. This Master’s Thesis takes a look at the current state and the future trends of the Finnish wood pellet industries. The domestic wood-based pellet industries are studied with a concise literature review and a SWOT analysis based on the earlier literature. The analysis is linked to the future expectations and current retailer perspectives with a survey conducted between June and October 2013. The sample consists of 39 low, medium and high sales volume wood pellet manufacturers and retailers whom mostly do only domestic pellet trading business. Most of the strengths of the domestic wood-based pellet industries are related to different kinds of ecological aspects or different kinds of raw material related issues. In the future especially the prices of the raw materials, prices of other energy sources and prices of the end-product will be in a crucial role. Most of the survey participants underlined the significance of the governmental acts concerning the future of the whole business in Finland: a favorable taxing policy and different subsidies can make Finland truly a greener economy but this have not happened yet, much due to the unfavorable domestic politics. According to the survey respondents, in the future the demand of wood-based pellet services, especially tailored and ready-to-use services from maintenance to deliveries are going to increase.
  • Hätönen, Katja (Helsingin yliopisto, 2014)
    Glycaemic response to carbohydrate-containing foods is a combination of glucose absorption, endogenous glucose production, and tissue glucose uptake. After a carbohydrate-containing meal, blood glucose rises, which stimulates insulin secretion. The different amount and type of carbohydrates influence postprandial glucose and insulin responses differently. The concept of the glycaemic index (GI) was developed to rank carbohydrates according to their effect on blood glucose levels. Food with a low GI value is considered beneficial in maintaining optimal blood glucose due to smaller incremental increase in blood glucose than food with a high GI value. Foods characterized by a low GI therefore have been found to induce benefits on several risk markers related to type 2 diabetes and cardiovascular disease. The concept of the GI was originally developed as a tool for individuals with diabetes in choosing the most beneficial carbohydrate-rich foods regarding blood glucose responses. To assess the extent to which eaten food raises insulin levels, the concept of the insulinaemic index (II) was launched. The calculation of II values is performed similarly to GI values. The concept of GI has been widely studied and debated in the scientific literature. The main aim of this thesis was to investigate the effect of methodological choices on measured glucose and insulin responses, especially on GI values. To achieve these goals, five different postprandial studies were conducted in healthy individuals and in individuals with impaired glucose tolerance. Capillary and venous blood samples were collected up to 2-3 h postprandially and the incremental area under the curve (IAUC), GIs, and IIs were calculated. In the first study, the effects of methodological choices on measured glycaemic response and GI values were determined. Comparisons were done between blood sampling type (capillary vs. venous blood samples), type of reference food (white bread vs. glucose solution), and how many times the reference food should be repeated. Results revealed that the variation was smaller when capillary samples were used, performing the reference food test twice is sufficient, and to achieve better accuracy the glucose solution should be used as the reference food. In the second study, the effects of coffee on postprandial glucose and insulin responses were determined. Coffee as such does not modify the glucose and insulin responses of a carbohydrate food. Coffee had no marked effect on GI values. In the third study, the effects of subjects physiological characteristics, namely glucose tolerance and overweight, on postprandial glucose and insulin responses were examined. Both overweight and impaired glucose tolerance increased glycaemic and insulinaemic responses to the tested meals and the reference food. As a consequence, physiological characteristics did not affect the measured GI values. In the fourth study, the effects of other macronutrients, namely fat and protein, on glycaemic responses to a starchy food were examined. Both fat and protein have an independent decreasing effect on glycaemia, and as a consequence, GI values diminished. Insulin responses to the meals were also measured. Adding protein to the mashed potato-based meals considerably enhanced insulin responses to the meal. In the fifth study, the effects of alcohol on postprandial glucose and insulin responses were determined. Alcohol was found to increase postprandial glucose and insulin responses, probably through acutely increased insulin resistance. In addition, high GI values were measured for both beer and non-alcoholic beer. This should be taken into account when GI databases are compiled for epidemiologic studies. In summary, several factors affect measured GI values, highlighting that different methodological choices should be carefully considered. The use of recent international standards, for measuring GI values is highly recommended, and GI values measured prior to the standard should be interpreted and utilized with caution. To increase the reliability of GI measurements in the future, GI should be measured in combination with II measurements.