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  • Nordman, Nina (Helsingin yliopisto, 2015)
    Analytical microsystems are attractive in modern bioanalysis where sample amounts often are low and fast analyses are required. Microsystems also provide the prospect of integrating several functional elements on a single platform. The aim of this work was to develop analytical microsystems for fast analysis of bio- and drug molecules. For this, microchips with separation- and injection channels and monolithically integrated electrospray ionization (ESI) emitter were fabricated of epoxy photoresist SU-8 by photolithography and adhesive bonding. For peptide mass fingerprinting and protein sequencing characteristic tryptic peptides were fast and easily separated and detected by microchip capillary electrophoresis (MCE)-ESI/mass spectrometry (MS). Additionally, protein identification based on tandem MS fragmentation data of a single tryptic peptide was achieved. Finally, this rapid (total analysis time below ten minutes) microchip method permitted analysis of human muscle cell lysates. For online coupling of microchip capillary isoelectric focusing (cIEF) to ESI/MS a bilateral sheath flow interface or a two-dimensional separation unit was integrated on-chip. Rapid focusing of peptides by their isoelectric points (pI) was achieved without pretreatment of the SU-8 surface. After focusing the peptides were electrokinetically mobilized toward ESI/MS. The two-dimensional chip design enabled unique separation selectivity for peptides based on both pI values and intrinsic electrophoretic mobilities by multiplex-cIEF-transient-isotachophoresis. Rapid metabolic profiling was demonstrated from urine after intake of tramadol or paracetamol. Both phase I- and II metabolites were separated and detected by MCE-ESI/MS within 35 s. In addition, Michaelis-Menten kinetics was successfully determined for the CYP450-mediated oxidation of bufuralol to 1-hydroxybufuralol. Sample preconcentration (pretreatment) was integrated on-chip by solid-phase extraction (SPE) and liquid-phase microextraction (LPME). For SPE, a monolith zone was firmly anchored at the injection cross of the MCE-ESI/MS microchip by laser induced photopolymerization. The monolith was selective toward hydrophobic and hydrophilic sample molecules and enrichment factors as high as 23-fold was achieved with a loading time as short as 25 s. In addition, LPME was easily downscaled to low volume applications and offered selectivity in the analysis of phase I metabolites compared to SPE. In contrast to previous research in the same field this work offers bioanalysis with several on-chip integrated steps (preconcentration, injection, separation, and analysis) without considerably increasing the short analysis times characteristic of microchip assays.
  • Sallisalmi, Marko (Helsingin yliopisto, 2013)
    The study was a prospective observational and methodological study performed among thirty-six critically-ill patients and twenty-six healthy controls subjects in 2008-2012 in two Finnish intensive care units. In critically-ill patients the blood flow among the microcirculation becomes disturbed, which predisposes the patients to multiple organ failure and death. The endothelial glycocalyx layer, which is formed on the vascular surface of endothelial cells is implicated in microcirculatory events in animal studies, but the data among critically-ill patients is scarce and based on laboratory samples only. The viscosity of plasma determines shearing forces of blood, and thus, the shear induced excretion of nitric oxide by the endothelial cells, i.e. mechanosensing. In animal models, increased plasma viscosity is associated with increased microvascular flow. Futhermore, the technology of microvascular and glycocalyx research in humans is under development. The evidence of molecular mechanisms and causal relation between endothelial glycocalyx damage and microcvascular disturbance in critically-ill patients is lacking. The feasibility and reliability of a standardized technical quality analysis for video images obtained from human sublingual microcirculation was tested in the first part of the study. By analysis of a novel previously unvalidated set of technical criteria by two independent investigators, only 31% of the analyzed 240 video images qualified techically for further use in clinical studies. In the second part of the study, a semi-automatic computer algorithm was created and validated for the measurement of glycocalyx layer thickness. Use of the semi-automatic algorithm in microcirculatory video images obtained from human oral cavity diminished the coefficient of variation of measured glycocalyx layer thickness from 7.2% - 9.8% in manual measurements to 4.3% - 5.8% in the semi-automatic measurements. Two separate hypothesis were tested in the third and fourth parts of the study. A hypothesis that activation of vascular adhesion protein-1, a novel adhesion epitope and enzyme, coincides with shedding of the glycocalyx in sepsis, was supported. The second hypothesis, that the shedding of the endothelial glycocalyx layer in sepsis leads to increased plasma viscosity, was rejected. Contrary to the study hypothesis the viscosity of plasma in patients with sepsis was not increased, but was lower than controls values for four days. Ex vivo it was evident that the type of fluid therapy administered during the course of early treatment among critically-ill patients determines plasma viscosity and, thus, the shearing properies of blood in the microcirculation.
  • Teye, Frederick Kwame (Helsingin yliopisto, 2008)
    The aim of this thesis was to develop measurement techniques and systems for measuring air quality and to provide information about air quality conditions and the amount of gaseous emissions from semi-insulated and uninsulated dairy buildings in Finland and Estonia. Specialization and intensification in livestock farming, such as in dairy production, is usually accompanied by an increase in concentrated environmental emissions. In addition to high moisture, the presence of dust and corrosive gases, and widely varying gas concentrations in dairy buildings, Finland and Estonia experience winter temperatures reaching below -40 ºC and summer temperatures above +30 ºC. The adaptation of new technologies for long-term air quality monitoring and measurement remains relatively uncommon in dairy buildings because the construction and maintenance of accurate monitoring systems for long-term use are too expensive for the average dairy farmer to afford. Though the documentation of accurate air quality measurement systems intended mainly for research purposes have been made in the past, standardised methods and the documentation of affordable systems and simple methods for performing air quality and emissions measurements in dairy buildings are unavailable. In this study, we built three measurement systems: 1) a Stationary system with integrated affordable sensors for on-site measurements, 2) a Wireless system with affordable sensors for off-site measurements, and 3) a Mobile system consisting of expensive and accurate sensors for measuring air quality. In addition to assessing existing methods, we developed simplified methods for measuring ventilation and emission rates in dairy buildings. The three measurement systems were successfully used to measure air quality in uninsulated, semi-insulated, and fully-insulated dairy buildings between the years 2005 and 2007. When carefully calibrated, the affordable sensors in the systems gave reasonably accurate readings. The spatial air quality survey showed high variation in microclimate conditions in the dairy buildings measured. The average indoor air concentration for carbon dioxide was 950 ppm, for ammonia 5 ppm, for methane 48 ppm, for relative humidity 70%, and for inside air velocity 0.2 m/s. The average winter and summer indoor temperatures during the measurement period were -7º C and +24 ºC for the uninsulated, +3 ºC and +20 ºC for the semi-insulated and +10 ºC and +25 ºC for the fully-insulated dairy buildings. The measurement results showed that the uninsulated dairy buildings had lower indoor gas concentrations and emissions compared to fully insulated buildings. Although occasionally exceeded, the ventilation rates and average indoor air quality in the dairy buildings were largely within recommended limits. We assessed the traditional heat balance, moisture balance, carbon dioxide balance and direct airflow methods for estimating ventilation rates. The direct velocity measurement for the estimation of ventilation rate proved to be impractical for naturally ventilated buildings. Two methods were developed for estimating ventilation rates. The first method is applicable in buildings in which the ventilation can be stopped or completely closed. The second method is useful in naturally ventilated buildings with large openings and high ventilation rates where spatial gas concentrations are heterogeneously distributed. The two traditional methods (carbon dioxide and methane balances), and two newly developed methods (theoretical modelling using Fick s law and boundary layer theory, and the recirculation flux-chamber technique) were used to estimate ammonia emissions from the dairy buildings. Using the traditional carbon dioxide balance method, ammonia emissions per cow from the dairy buildings ranged from 7 g day-1 to 35 g day-1, and methane emissions per cow ranged from 96 g day-1 to 348 g day-1. The developed methods proved to be as equally accurate as the traditional methods. Variation between the mean emissions estimated with the traditional and the developed methods was less than 20%. The developed modelling procedure provided sound framework for examining the impact of production systems on ammonia emissions in dairy buildings.
  • Nokso-Koivisto, Inka (2014)
    The microcosm-macrocosm analogy – the idea of man as a miniature of the surrounding reality or part of it – is a prevailing theme in Rasail Ikhwan as-Safa. This study examines the analogy primarily in this encyclopaedia completed during the tenth century and compares the views presented in it to those in certain other texts from the ninth to the thirteenth centuries: Sirr al-khaliqa, some texts attributed to Jabir ibn Hayyan, some Sufi writings of al-Ghazali (d. 1111), Suhrawardi (d. 1191) and Ibn Arabi (d. 1240), and al-Qazwini’s (d. 1283) Ajaib al-makhluqat. The aim is to explore the influence of microcosmism on the idea of man in these texts and to define the position of the Rasail in the development of the topic in mediaeval Islamic thought. Rudolf Allers’s classification of microcosmism is used as the main conceptual framework in this analysis. All Allers’s six varieties of the analogy receive various interpretations in the Islamic tradition. This study also proposes a threefold approach to the examination of microcosmism. Firstly, the analogy appears as a human-specific feature defining the cosmological position of the human species. In this form, microcosmism is used in all of the studied texts and often the role of the human being as an intermediate being in the universe is in focus. Secondly, attitudes towards the corporeal aspect of man are approached through the use of the analogy. In this form, the idea is closely related to the scientific worldview and sometimes the meaning given to the analogy can only be understood within the frames of a scientific theory. Thirdly, the normative aspect is included in the analogy and it is used in descriptions of epistemological and ethical ideals. Especially Sufi thinkers elaborate this form of the analogy and it is also in the key position of microcosmism in the Rasail. Microcosmism in the Rasail is a synthesis of various forms of the analogy developed earlier in the Islamic tradition and it anticipates many ideas that only become central in the later texts. Obvious thematic similarities between the texts can be found, but transmission of particular elements of microcosmism is possible to trace in only a few cases. For instance, some comparisons of the Rasail between the human body and the surrounding reality seem to be transmitted – directly or indirectly – even to the latest texts of the corpus.
  • Uddin, Mohammad Jasim (Helsingin yliopisto, 2013)
    This dissertation seeks to shed light on microcredit policies and practices, and attempts to contribute to the understanding of how microcredit relates to the lives of the borrowers in rural Bangladesh. More specifically, this study delves into whether the group-based micro-loans that are channeled through women facilitate social capital, reconstruct gender relations and provide a way out of poverty at the village level in Bangladesh. The empirical data of this study was collected from 151 married women microcredit borrowers of two project areas of the Grameen Bank (GB) and two project areas of the Bangladesh Rural Advancement Committee (BRAC) in the Sylhet District, Bangladesh where both the GB and the BRAC have been operating micro-loans over a period of several years. The ethnographic description relates to the questions of how NGOs use neoliberal policies and credit on the one hand, and also how local people appropriate credit on the other hand. I have endeavoured to contribute to understanding the focuses of microcredit initiatives within the context of Foucault s disciplinary power (1977) and governmentality (1978, 1979, 1988) against the background of neoliberalism. I stress the power relations, implications of enforced institutional discipline of microcredit organizations, and vulnerability of microcredit borrowers. By applying Scott s notions of hidden resistance (1990) and weapons of the weak (1985), I have focused on how microcredit borrowers criticize rules of programmes and procedures out of earshot and out of sight of the officials of the NGOs. Following the entitlement approach detailed by Sen (1981, 1987, 1999) I have also addressed the mechanism whereby poor people take credit year after year and get further mired in debt. Fundamentally, the objective of this study has rotated around some complex questions: To what extent microcredit programmes, a product of neoliberalism and the capitalist world system, intersect and connect with the local women borrowers to facilitate social capital, women s empowerment and poverty alleviation in rural Bangladesh? Does the group lending tenet really work, or is it only a process of getting access to credit for the borrowers or does it fulfil a governing strategy of microcredit organizations to the borrowers in accordance with the market rationality? Are women microcredit borrowers really rational economic actors who invest credit themselves at the local level? Is credit through women a policy of women s empowerment or a project of covert regulative practice? Are the microcredit borrowers undergoing the win-win situation of increased financial outcomes and enhanced well-being that microcredit programmes have pledged to offer? My work draws attention to what microcredit NGOs aim to change, and the techniques they apply. My study is an analysis of what microcredit initiatives fail to do: mobilize social capital, reconstruct gender relations, and alleviate poverty. The study argues that microcredit can be regard as a form of governmentality that is exercised via a generalised control over people s behaviour and over their beliefs, and by spreading the values of entrepreneurship with the market as the solver of all ills. Whilst the much lauded microcredit organizations (such as GB, BRAC) push neoliberal ideologies onto rural borrowers, they have failed because many borrowers cannot yield sufficient profit and or use credit for the purposes for which it is supposed to be used for. The package of training and consciousness raising lessons that originally went alongside the GB or BRAC microcredit programme is now missing from their rural operations. Therefore, ensuring a win-win situation that microcredit originally promised has been failed. Microcredit organizations reinforce pre-existing kinship and gender structures, and there has been a wide scale mission creep, which has turned micro-lending NGOs into money-lending businesses or installment collecting organizations.
  • Verho, Jouko (Helsingfors universitet, 2008)
    This dissertation consists of four essays studying topics in empirical labour economics. The first essay evaluates the impact of an unemployment benefit reform in Finland. In 2003, the benefit level was increased in Finland for workers with long employment histories. The average benefit increase was 15% for the first 150 days of the unemployment spell. This study evaluates the effect of the benefit increase on the duration of unemployment by comparing the changes in the re-employment hazard profiles among the unemployed who became eligible for the increased benefits to the changes in a comparison group whose benefit structure remained unchanged. According to the results benefit increase reduced the re-employment hazards by on average 16%. The effect is largest at the beginning of the unemployment spell and disappears after the eligibility period for the increased benefits expires. The second essay analyses the long-term costs of unemployment in Finland by focusing on the deep recession period of 1991 - 1993. The number of plant closures increased sharply during the recession and the unemployment rate rose by more than 13 percentage points. In the analysis, prime working-age men who face unemployment due to plant closure are matched to those who remained employed during the recession. The effect of being unemployed during the recession is estimated for a 6 year follow-up period. In 1999, the unemployed individuals suffer a 25% loss in annual earnings, 10% reduction in employment and 14% wage scar. The third essay focuses on the recession of the early 1990s that caused a serious unemployment problem in Finland. This study analyses the determinants of unemployment duration using individual data from 1987 to 2000. Duration until employment is modelled using a proportional hazard model with piecewise constant baseline hazard. The main focus is on the relative contribution of compositional variation and macroeconomic conditions to unemployment duration. According to the results, the aggregate outflow effect dominates and the observed compositional variation implies only a small increasing trend in the average duration during the recession period. The last essay studies the effect of business cycle on the incidence of workplace accidents. Individual data covering Swedish inhospital care 1997 - 2005 is linked to the population database. These data allow studying if changes in the composition of workers or strategic worker behaviour are driving the cyclicality of accidents. The results show that the incidence of workplace accidents increases during economic upturns but only in specific subgroups. Some evidence is found that compositional changes in labour force may contribute to cyclicality for women. In the male population, on the other hand, only the less severe accidents are cyclical which would be consistent with strategic worker behaviour.
  • Razzauti Sanfeliu, Maria (Helsingin yliopisto, 2012)
    Puumala hantavirus (PUUV) is a zoonotic virus that in humans causes nephropathia epidemica (NE) in humans, a mild form of haemorrhagic fever with renal syndrome. An average of 10 000 cases are reported annually in Europe, many of which occur in Fennoscandia. The incidence of NE is connected to the distribution and population density of the the bank vole (Myodes glareolus), the main virus host. In Fennoscandia, high incidences of NE occur at 3-4 year intervals due to the characteristic population cycles of this woodland rodent. This study aimed to gain a better understanding of PUUV microevolution by examining genetic features of the virus in several bank vole populations of Finland and Latvia. Genetic variation in PUUV circulating in a bank vole population at Konnevesi in Central Finland was examined and monitored over five-years throughout a complete bank vole cycle, including two peak-phases in 2005 and 2008 and two population declines in 2006 and 2009 (i.e., viral bottlenecks). Altogether, 1369 bank voles were captured and 26.3% were detected PUUV-infected. Partial sequences of the three viral genome segments (Small, Medium and Large) were inspected from 365 PUUV genomes. Genetic diversity was 6.2% for the S segment, 4.8% for the M segment, and a surprisingly high 10.1% for the L segment. Each genome segment had accumulated mutations as a separate gene pool. The majority of nucleotide substitutions were synonymous and most of the deduced amino acid substitutions were conservative, suggesting a strong stabilizing selection operating at the protein level. Genetic markers found along the genome segments allowed for the recognition of two genogroups of PUUV co-circulating in the host population. Even though, one of the genogroups presented higher genetic diversity, no signs of completion were observed between them. Nearly 80% the variants exhibited a transient existence, and frequently occurring variants were integrated by most abundant segment genotypes suggesting a viral mutational robustness. A substantial portion (19.1%) of genomes appeared to be reassorted, with S and M typically being exchanged. Reassorted variants did not outcompete parental variants and were commonly transient. Reassortment was seasonal, occurring more frequently in autumn when recent infection risk increases. An imperceptible intra-genogroup reassortment could contribute to the steady state of the viral population, counteracting the effects of Muller s ratchet. Co-circulation and interaction of two distinct PUUV lineages (Finnish and North-Scandinavian) was monitored in a bank vole population at Pallasjärvi in Northern Finland. To date, seven genetic lineages have been detected, all of which exhibit geographic structure within the host distribution. Here, we present new evidence of two lineages circulating in the same bank vole phylogroup (Ural clade). Genetic diversity within each PUUV lineage was modest (up to 1.7%) and most substitutions were synonymous. However, genetic differences between the two lineages were as high as 18.9%. Phylogenetic analyses revealed that these distinct lineages naturally reassort with a frequency comparable to that genogroups circulating at Konnevesi, i.e., 32%. In contrast to Konnevesi, only M segment was exchanged between PUUV lineages at Pallasjärvi. Two distinct PUUV lineages were also found to co-circulate in Latvia. One (Russian) has been previously described and the other awaits formal description. The novel Latvian lineage is considerably divergent from other PUUV lineages and several amino acid markers made it easily distinguishable. Phylogenetic analysis suggested an independent evolutionary history for the segments of Latvian lineage. Similar to Pallasjärvi, both Russian and Latvian lineages were found in a single bank vole phylogroup (Carpathian clade), confirming earlier observations that PUUV lineages are not limited to a single host phylogroup.
  • Heino, Antti (Helsingin yliopisto, 2010)
    Milk microfiltration (0.05-0.2 um) is a membrane separation technique which divides milk components into casein-enriched and native whey fractions. Hitherto the effect of intensive microfiltration including a diafiltration step for both cheese and whey processing has not been studied. The microfiltration performance of skimmed milk was studied with polymeric and ceramic MF membranes. The changes caused by decreased concentration of milk lactose, whey protein and ash content for cheese milk quality and ripening were studied. The effects of cheese milk modification on the milk coagulation properties, cheese recovery yield, cheese composition, ripening and sensory quality as well as on the whey recovery yield and composition by microfiltration were studied. The functional properties of whey protein concentrate from native whey were studied and the detailed composition of whey protein concentrate powders made from cheese wheys after cheese milk pretreatments such as high temperature heat treatment (HH), microfiltration (MF) and ultrafiltration (UF) were compared. The studied polymeric spiral wound microfiltration membranes had 38.5% lower energy consumption, 30.1% higher retention of whey proteins to milk retentate and 81.9% lower permeate flux values compared to ceramic membranes. All studied microfiltration membranes were able to separate main whey proteins from skimmed milk. The optimal lactose content of Emmental cheese milk exceeded 3.2% and reduction of whey proteins and ash content of cheese milk with high concentration factor (CF) values increased the rate of cheese ripening. Reduction of whey protein content in cheese milk increased the concentration of caseinomacropeptide (CMP) of total proteins in cheese whey. Reduction of milk whey protein, lactose and ash content reduces milk rennet clotting time and increased the firmness of the coagulum. Cheese yield calculated from raw milk to cheese was lower with microfiltrated milks due to native whey production. Amounts of a-lactalbumin (a-LA) and b-lactoglobulin (b-LG) were significantly higher in the reference whey, indicating that HH, MF and UF milk pretreatments decrease the amounts of these valuable whey proteins in whey. Even low CF values in milk microfiltration (CF 1.4) reduced nutritional value of cheese whey. From the point of view of utilization of milk components it would be beneficial if the amount of native whey and the CMP content of cheese whey could be maximized. Whey protein concentrate powders made of native whey had excellent functional properties and their detailed amino acid composition differed from those of cheese whey protein concentrate powders.
  • Islam, K M Zahidul (Helsingin yliopisto, 2011)
    The objectives of this study were to make a detailed and systematic empirical analysis of microfinance borrowers and non-borrowers in Bangladesh and also examine how efficiency measures are influenced by the access to agricultural microfinance. In the empirical analysis, this study used both parametric and non-parametric frontier approaches to investigate differences in efficiency estimates between microfinance borrowers and non-borrowers. This thesis, based on five articles, applied data obtained from a survey of 360 farm households from north-central and north-western regions in Bangladesh. The methods used in this investigation involve stochastic frontier (SFA) and data envelopment analysis (DEA) in addition to sample selectivity and limited dependent variable models. In article I, technical efficiency (TE) estimation and identification of its determinants were performed by applying an extended Cobb-Douglas stochastic frontier production function. The results show that farm households had a mean TE of 83% with lower TE scores for the non-borrowers of agricultural microfinance. Addressing institutional policies regarding the consolidation of individual plots into farm units, ensuring access to microfinance, extension education for the farmers with longer farming experience are suggested to improve the TE of the farmers. In article II, the objective was to assess the effects of access to microfinance on household production and cost efficiency (CE) and to determine the efficiency differences between the microfinance participating and non-participating farms. In addition, a non-discretionary DEA model was applied to capture directly the influence of microfinance on farm households production and CE. The results suggested that under both pooled DEA models and non-discretionary DEA models, farmers with access to microfinance were significantly more efficient than their non-borrowing counterparts. Results also revealed that land fragmentation, family size, household wealth, on farm-training and off farm income share are the main determinants of inefficiency after effectively correcting for sample selection bias. In article III, the TE of traditional variety (TV) and high-yielding-variety (HYV) rice producers were estimated in addition to investigating the determinants of adoption rate of HYV rice. Furthermore, the role of TE as a potential determinant to explain the differences of adoption rate of HYV rice among the farmers was assessed. The results indicated that in spite of its much higher yield potential, HYV rice production was associated with lower TE and had a greater variability in yield. It was also found that TE had a significant positive influence on the adoption rates of HYV rice. In article IV, we estimated profit efficiency (PE) and profit-loss between microfinance borrowers and non-borrowers by a sample selection framework, which provided a general framework for testing and taking into account the sample selection in the stochastic (profit) frontier function analysis. After effectively correcting for selectivity bias, the mean PE of the microfinance borrowers and non-borrowers were estimated at 68% and 52% respectively. This suggested that a considerable share of profits were lost due to profit inefficiencies in rice production. The results also demonstrated that access to microfinance contributes significantly to increasing PE and reducing profit-loss per hectare land. In article V, the effects of credit constraints on TE, allocative efficiency (AE) and CE were assessed while adequately controlling for sample selection bias. The confidence intervals were determined by the bootstrap method for both samples. The results indicated that differences in average efficiency scores of credit constrained and unconstrained farms were not statistically significant although the average efficiencies tended to be higher in the group of unconstrained farms. After effectively correcting for selectivity bias, household experience, number of dependents, off-farm income, farm size, access to on farm training and yearly savings were found to be the main determinants of inefficiencies. In general, the results of the study revealed the existence substantial technical, allocative, economic inefficiencies and also considerable profit inefficiencies. The results of the study suggested the need to streamline agricultural microfinance by the microfinance institutions (MFIs), donor agencies and government at all tiers. Moreover, formulating policies that ensure greater access to agricultural microfinance to the smallholder farmers on a sustainable basis in the study areas to enhance productivity and efficiency has been recommended. Key Words: Technical, allocative, economic efficiency, DEA, Non-discretionary DEA, selection bias, bootstrapping, microfinance, Bangladesh.
  • Pessi, Jenni (2013)
    Polymer microspheres hold great potential as oral drug delivery system for therapeutic proteins. Microspheres prepared with biocompatible and biodegredable polymers have been extensively studied, since the oral delivery of therapeutic proteins is challenging due to the conditions in the GI-tract. The aims of this research were to apply microfluidics on polymeric microsphere preparation process, to determine what kind of formulations are suitable for this technology, to establish a controlled preparation process that produces advanced particles and to create a template for oral protein drug delivery. With microfluidic fabrication it is possible to gain control over the process and content of each droplet. However, finding suitable formulations for microfluidics is demanding. In this study, biphasic flow was employed to successfully produce double (W/O/W) emulsion droplets with ultra thin shells. Once the process and formulation variables were optimized constant droplet production was achieved. Flow rates used were 500 μl/h in the inner and in the middle phase and 2500 μl/h in the outer phase, respectively. Two formulations were selected for further characterization: 5 % poly(vinyl alcohol) in water in the outer phase, 3 % polycaprolactone in ethyl acetate in the middle phase and either 10 % or 20 % poly(vinyl alcohol) and polyethylenglycol (1:4) in water in the inner phase. All the particles were found to be intact and contain the inner phase, as verified by confocal microscopy. Further, the particles were monodisperse and non-porous, as observed by scanning electron microscopy. Particle size was found to be around 20-40 μm, variation in the particle size within one batch was small and the particles were stable up to 4 weeks. The encapsulation efficiency of the particles was remarkable; as high as 85 % loading of the model compound, bovine serum albumin. Particles released 30 % of their content within 48 hours. In conlusion, developing functional formulations for micfoluidic technology was possible, the microparticles encapsulated the model protein extremely well and all in all microfluidic technology had a lot of potential for droplet manufacturing for pharmaceutical applications.
  • Markkanen, Tiina (Helsingin yliopisto, 2004)
  • Ylä-Kotola, Tuija (Helsingin yliopisto, 2008)
    Microneurovascular free muscle transfer with cross-over nerve grafts in facial reanimation Loss of facial symmetry and mimetic function as seen in facial paralysis has an enormous impact on the psychosocial conditions of the patients. Patients with severe long-term facial paralysis are often reanimated with a two-stage procedure combining cross-facial nerve grafting, and 6 to 8 months later with microneurovascular (MNV) muscle transfer. In this thesis, we recorded the long-term results of MNV surgery in facial paralysis and observed the possible contributing factors to final functional and aesthetic outcome after this procedure. Twenty-seven out of forty patients operated on were interviewed, and the functional outcome was graded. Magnetic resonance imaging (MRI) of MNV muscle flaps was done, and nerve graft samples (n=37) were obtained in second stage of the operation and muscle biopsies (n=18) were taken during secondary operations.. The structure of MNV muscles and nerve grafts was evaluated using histological and immunohistochemical methods ( Ki-67, anti-myosin fast, S-100, NF-200, CD-31, p75NGFR, VEGF, Flt-1, Flk-1). Statistical analysis was performed. In our studies, we found that almost two-thirds of the patients achieved good result in facial reanimation. The longer the follow-up time after muscle transfer the weaker was the muscle function. A majority of the patients (78%) defined their quality of life improved after surgery. In MRI study, the free MNV flaps were significantly smaller than originally. A correlation was found between good functional outcome and normal muscle structure in MRI. In muscle biopsies, the mean muscle fiber diameter was diminished to 40% compared to control values. Proliferative activity of satellite cells was seen in 60% of the samples and it tended to decline with an increase of follow-up time. All samples showed intramuscular innervation. Severe muscle atrophy correlated with prolonged intraoperative ischaemia. The good long-term functional outcome correlated with dominance of fast fibers in muscle grafts. In nerve grafts, the mean number of viable axons amounted to 38% of that in control samples. The grafted nerves characterized by fibrosis and regenerated axons were thinner than in control samples although they were well vascularized. A longer time between cross facial nerve grafting and biopsy sampling correlated with a higher number of viable axons. P75Nerve Growth Factor Receptor (p75NGFR) was expressed in every nerve graft sample. The expression of p75NGFR was lower in older than in younger patients. A high expression of p75NGFR was often seen with better function of the transplanted muscle. In grafted nerve Vascular Endothelial Growth Factor (VEGF) and its receptors were expressed in nervous tissue. In conclusion, most of the patients achieved good result in facial reanimation and were satisfied with the functional outcome. The mimic function was poorer in patients with longer follow-up time. MRI can be used to evaluate the structure of the microneurovascular muscle flaps. Regeneration of the muscle flaps was still going on many years after the transplantation and reinnervation was seen in all muscle samples. Grafted nerves were characterized by fibrosis and fewer, thinner axons compared to control nerves although they were well vascularized. P75NGFR and VEGF were expressed in human nerve grafts with higher intensity than in control nerves which is described for the first time.
  • Falck, Ghita (Helsingin yliopisto, 2014)
    The formation of micronuclei (MN) in peripheral blood lymphocytes represents one of the earliest cytogenetic effects of exposure to genotoxic carcinogens. An increased frequency of MN and of other cytogenetic alterations, such as chromosomal aberrations and sister chromatid exchanges, in a well-controlled study of occupationally exposed people, is usually considered a strong indication of exposure to genotoxic carcinogens, requiring improvements in protective measures. Such considerations are further supported by epidemiological studies, suggesting that a high frequency of chromosomal aberrations and MN is predictive of an increased risk of cancer. This study was performed to obtain comprehensive information about the suitability of the lymphocyte micronucleus assay (MN assay) in examining the effects of occupational exposure to genotoxic carcinogens. MN, defined as small, additional nuclei, are formed in mitosis from acentric chromosomal fragments or chromosomes that lag behind in anaphase and eventually fail to be included in either of the daughter nuclei. The primary objectives of this dissertation were to clarify factors affecting the mechanistic origin of MN and to assess the influence of some methodological aspects in the MN assay. The differentiation of MN harbouring fragments from those containing whole chromosomes was considered a main goal, in order to estimate whether these two classes of MN should be analyzed separately. Methodologically, the influence of cell culture time and the use of the cytokinesis-block method on the frequency and contents of MN were assessed, as well as the possibility to analyze MN in vivo from uncultured T-lymphocytes. In addition, the suitability of bromodeoxyuridine (BrdU) labeling as an alternative method to the cytokinesis-block technique was investigated in greenhouse workers occupationally exposed to pesticides. Furthermore, some genetic polymorphisms (GSTM1, GSTT1 and NAT2) were also studied in the greenhouse workers to reveal their possible role as modifiers of individual response to the occupational exposure. Finally, mechanistic aspects concerning the formation of MN from chromosomes and fragments lagging behind in anaphase, with a special reference to the X chromosome, were assessed. By using pancentromeric fluorescence in situ hybridization (FISH), considerable proportions of MN were found to contain whole chromosomes or chromatids. The frequency of this type of MN was both age- and culture-time-dependent. Micronucleus analysis using the anti-BrdU staining technique showed that the pesticide-exposed greenhouse workers, in particular exposed smokers, had a higher micronucleus frequency than their respective controls. Subjects with the GSTM1 positive and NAT2 fast acetylator genotypes had higher frequencies of MN, but this effect was not related to the pesticide exposure. Comparison of the proportion of various types of MN in cultured and uncultured T-lymphocytes of women, using a pancentromeric and a centromeric X-chromosome specific DNA probe, indicated that in vivo MN in T-lymphocytes primarily consist of whole chromosomes, especially the X-chromosome. In general, the X chromosome was highly over-represented in female MN, and cell culture further increased the frequency of X-chromosome-positive MN. The high micronucleation of the X-chromosome appeared to be due to its frequent lagging behind in anaphase. Reciprocal chromosome gain and loss in lymphocytes was more common for the X-chromosome both in men and women than for the Y-chromosome in men. The results of this dissertation strongly suggest that, when MN are used as a biomarker of human genotoxic effects, the recognition of the contents of MN is of utmost importance and is expected to improve the specificity and sensitivity of the assay. Furthermore, the direct analysis of MN in uncultured peripheral T lymphocytes, combined with centromeric FISH, may provide a new possibility for the assessment of chromosome breakage and numerical chromosome alterations occurring in vivo.
  • Nissilä, Teemu (Helsingin yliopisto, 2011)
    This dissertation deals with the design, fabrication, and applications of microscale electrospray ionization chips for mass spectrometry. The microchip consists of microchannel, which leads to a sharp electrospray tip. Microchannel contain micropillars that facilitate a powerful capillary action in the channels. The capillary action delivers the liquid sample to the electrospray tip, which sprays the liquid sample to gas phase ions that can be analyzed with mass spectrometry. The microchip uses a high voltage, which can be utilized as a valve between the microchip and mass spectrometry. The microchips can be used in various applications, such as for analyses of drugs, proteins, peptides, or metabolites. The microchip works without pumps for liquid transfer, is usable for rapid analyses, and is sensitive. The characteristics of performance of the single microchips are studied and a rotating multitip version of the microchips are designed and fabricated. It is possible to use the microchip also as a microreactor and reaction products can be detected online with mass spectrometry. This property can be utilized for protein identification for example. Proteins can be digested enzymatically on-chip and reaction products, which are in this case peptides, can be detected with mass spectrometry. Because reactions occur faster in a microscale due to shorter diffusion lengths, the amount of protein can be very low, which is a benefit of the method. The microchip is well suited to surface activated reactions because of a high surface-to-volume ratio due to a dense micropillar array. For example, titanium dioxide nanolayer on the micropillar array combined with UV radiation produces photocatalytic reactions which can be used for mimicking drug metabolism biotransformation reactions. Rapid mimicking with the microchip eases the detection of possibly toxic compounds in preclinical research and therefore could speed up the research of new drugs. A micropillar array chip can also be utilized in the fabrication of liquid chromatographic columns. Precisely ordered micropillar arrays offer a very homogenous column, where separation of compounds has been demonstrated by using both laser induced fluorescence and mass spectrometry. Because of small dimensions on the microchip, the integrated microchip based liquid chromatography electrospray microchip is especially well suited to low sample concentrations. Overall, this work demonstrates that the designed and fabricated silicon/glass three dimensionally sharp electrospray tip is unique and facilitates stable ion spray for mass spectrometry.
  • Mosakhani, Neda (Helsingin yliopisto, 2013)
    Recently, discovery of microRNA has provided new insights into cancer research, revealing the role of miRNAs in various biological processes, and evidence shows that their deregulation in many cancers has prognostic and predictive significance. Although specific miRNAs have been discovered in the malignancies studied in this thesis: colorectal cancer (CRC), giant cell tumor of bone (GCTB), acute lymphoblastic leukemia (ALL), and acute myeloid leukemia (AML), very little still is known about the association of miRNAs with progression and their response to treatment. By applying novel microarray techniques, we profiled miRNA expression in CRC, GCTB, ALL and, AML. In the study focusing on primary tumors of 60 metastatic CRC (mCRC) patients, we detected BRAF mutations in 5 and KRAS mutations in 15 cases. In addition to 46 altered miRNAs in mCRC patients with and without KRAS mutation vs. normal colon tissue, we observed an miRNA signature associated with KRAS status when we compared 15 patients with mutant KRAS with 40 patients without this mutation. Four differentially expressed miRNAs, over-expressed miR-92a, miR-127-3p, miR-486-5p, and under-expressed miR-378, were evident in the mutated KRAS group vs. wild-type KRAS group. In another study on CRC, miRNA profiling in primary tumors of 33 mCRC patients with wild-type BRAF and KRAS allowed identification of miRNAs related to their response to anti-EGFR monoclonal antibody treatment. We found up-regulated miR-31* and down-regulated miR-592 in progressive disease (PD) compared to that in disease control (DC). Evaluation of mRNA levels of SLC26A3 and ATN1, drug-related genes and of miR-31* target genes showed their lower level of expression in PD vs. DC. Moreover, correlation between overall survival and miRNA expression assessed by two approaches, cluster analysis and the Cox proportional hazard regression model, revealed two common miRNAs, miR-140-3p and miR-1224-5p, to be related to survival in both analyses. As for the study of the metastatic and non-metastatic GCTBs, we found 12 miRNAs as being differentially expressed (miR-136, miR-513a-5p, miR-494, miR-224, miR-542-5p). Expression levels of eight genes such as NFIB, TNC, and FLRT2 correlated inversely with miRNA results. The expression levels of miR-136 and its target gene, NFIB, were verified by use of qRT-PCR. The level of NFIB protein also was higher in metastatic than in non-metastatic GCTBs. Further, we tested the protein expression level of NFIB in an independent validation cohort of 74 primary archival GCTB specimens to assess the power of NFIB as a prognostic marker. Immunodetection showed a higher frequency of NFIB over-expression in primary tumors that developed metastases than in the disease-free group. Moreover, we studied the miRNA expression profiles of primary tumors of 90 bone marrow core biopsies of ALL patients, including 11 patients with paired samples at diagnosis and at relapse. We found a set of miRNAs (miR-1281, miR-1225-3p, miR-877*, miR-423-5p, miR-29c) significantly related to survival (q less than 0.05). Further validation of miR-423-5p expression by qRT-PCR confirmed microarray analysis results and showed a direct correlation with survival. In comparisons between the diagnosis-relapse pairs, expression of miR-654-5p and miR-431 between the two groups significantly differed, and these miRNAs were down-regulated in relapse samples. Comparison of miRNA profiling of 15 chemorefractory and 18 chemosensitive AML patients showed that the differentially expressed miRNAs were miR-363, miR-532-5p, and 342-3p, all of which were over-expressed in chemorefractory vs. chemosensitive patients. Verification by use of qRT-PCR of both miR-363 and miR-532-5p revealed similar results as with microarray. The miR-363 target genes RGS17 and HIPK3 both have been associated with drug response. These studies provide new information about genomic changes involved in progression and resistance to treatment in various types of cancer, and also highlight the power of applying genomic-wide array screening techniques in malignancies. The novel findings in these studies may serve as a useful resource for future studies and aid in development of novel therapeutic targets to increase the survival rates of cancer patients.
  • Veija, Tuukka (2014)
    Introduction: Merkel cell carcinoma (MCC) is a rare neuroendocrine cancer of the skin that has a strong propensity to relapse and metastasize. Exposure to ultraviolet radiation and immunosuppression contribute to MCC. Merkel cell polyomavirus (MCV) is detected in 70% to 80% of MCC tumors, but the significance of MCV infection is not yet understood. MicroRNAs (miRNA) have been reported to associate with many types of cancer, and miRNA profiles of other cancers with a virus etiology have been defined. The aim of this study was to compare the expression of five miRNAs, miR-34a, miR-30a, miR-1539, miR-142-3p and miR-181d in formalin fixed paraffin embedded MCC tumor samples according to MCV status using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Materials and methods: Sufficient RNA was extracted from 26 tumor samples and from control skin sample using the miRNeasy FFPE Kit (QIAGEN, Valencia, CA, USA). Reverse transcription of the RNA was done using the miScript II RT Kit (50) (QIAGEN). QRT-PCR was executed with miScript SYBR Green PCR Kit (QIAGEN).and LightCycler 480 instrument (Roche Diagnostics GmbH, Mannheim, Germany). Student’s t-test and Mann-Whitney U-test were used to evaluate differences in miRNA expression. Results: We found a statistically significant underexpression of mir-34a in MCV-negative tumors compared to MCV-positives. The other four miRNAs studied did not show significant expression differences according to MCV-status. There was no statistically significant difference in miRNA expression according to tumor location or metastasizing. Conclusion: The difference in miRNA expression according to MCV-status suggests distinct pathogenesis of the tumors. The role of underexpressed miR-34a in MCV-negative tumor pathogenesis remains unclear but it might be consequential in the tumorigenesis of MCV-negative tumors.
  • Zhou, Meng (2012)
    Nowadays, microsimulation method has been introduced to different fields, such as Social Science, Medicine research and Economic study. This method evaluates the effects of the proposed interventions or policies before they are implemented in the real world. In this article, I concentrate on microsimulation method used in Social Science by firstly explaining two main streams in microsimulation world, Static approach and Dynamic approach, in them, how statistical models are used are carefully explained by giving examples in Dynamic approach. In the following section, a Norwegian case is studied, this case gives the typical example of how the dynamic microsimulation used in the labor force and child care research, the effects of four different reform options are measured in this study. In the last section, the empirical study of a Finnish static microsimulation model-JUTTA is carried out. The uncertainty of JUTTA is assessed and one of its sub model called Toimtuki (income-related supplementary benefit) is detected to have space to be more accurate. In order to do so, two statistical models- Linear Regression model and Two-Stage Least Squares (2SLS) model are applied to it. From their results and diagnostics, we could conclude that both the Linear Regression and 2SLS successfully improves the accuracy of TOIMTUKI to some extent. Key Words: Static microsimulation, Dynamic microsimulation, JUTTA, assessment, 2SLS
  • Grenfell, Russell John (2011)
    A comparison of microsite occupancy and the spatial structure of regeneration in three areas of late-successional Norway spruce dominated forest. Pallas-Ylläs is understood to have been influenced only by small-scale disturbance; Dvina-Pinega has had sporadic larger-scale disturbances; Kazkim has been affected by fire. All spruce and birch trees with diameter at breast height (DBH) ≥10 cm were mapped in five stands on 40 m x 400 m transects, and those with DBH < 10 cm on 2 or 4 m x 400 m subplots. Microsite type was inventoried at 1m intervals along the centre line and for each tree with DBH < 10 cm. At all study areas small seedlings (h < 0.3 m, DBH < 10 cm) preferentially occupied disturbed microsites. In contrast, spruce saplings (h ≥ 1.3 m, DBH <10 cm) at all study areas showed less, or no, preference. At Pallas-Ylläs spruce seedlings (h < 1.3 m, DBH < 10 cm) and saplings (h ≥ 1.3 m, DBH < 10 cm) exhibited spatial correlation at scales from 32-52 m. At Dvina-Pinega saplings of both spruce and birch exhibited spatial correlation at scales from 32-81 m. At Kazkim spatial correlation of seedlings and saplings of both species was exhibited over variable distances. No spatial cross-correlation was found between overstorey basal area (DBH ≥ 10 cm) and regeneration (h ≥ 1.3 m, DBH < 10 cm) at any study area. The results confirm the importance of disturbed microsites for seedling establishment, but suggest that undisturbed microsites may sometimes be more advantageous for long-term tree survival. The regeneration gap concept may not be useful in describing the regeneration dynamics of late-successional boreal forests.
  • Marjamaa, Johan (Helsingin yliopisto, 2009)
    The rupture of a cerebral artery aneurysm causes a devastating subarachnoid hemorrhage (SAH), with a mortality of almost 50% during the first month. Each year, 8-11/100 000 people suffer from aneurysmal SAH in Western countries, but the number is twice as high in Finland and Japan. The disease is most common among those of working age, the mean age at rupture being 50-55 years. Unruptured cerebral aneurysms are found in 2-6% of the population, but knowledge about the true risk of rupture is limited. The vast majority of aneurysms should be considered rupture-prone, and treatment for these patients is warranted. Both unruptured and ruptured aneurysms can be treated by either microsurgical clipping or endovascular embolization. In a standard microsurgical procedure, the neck of the aneurysm is closed by a metal clip, sealing off the aneurysm from the circulation. Endovascular embolization is performed by packing the aneurysm from the inside of the vessel lumen with detachable platinum coils. Coiling is associated with slightly lower morbidity and mortality than microsurgery, but the long-term results of microsurgically treated aneurysms are better. Endovascular treatment methods are constantly being developed further in order to achieve better long-term results. New coils and novel embolic agents need to be tested in a variety of animal models before they can be used in humans. In this study, we developed an experimental rat aneurysm model and showed its suitability for testing endovascular devices. We optimized noninvasive MRI sequences at 4.7 Tesla for follow-up of coiled experimental aneurysms and for volumetric measurement of aneurysm neck remnants. We used this model to compare platinum coils with polyglycolic-polylactic acid (PGLA) -coated coils, and showed the benefits of the latter in this model. The experimental aneurysm model and the imaging methods also gave insight into the mechanisms involved in aneurysm formation, and the model can be used in the development of novel imaging techniques. This model is affordable, easily reproducible, reliable, and suitable for MRI follow-up. It is also suitable for endovascular treatment, and it evades spontaneous occlusion.
  • Microtia 
    Suutarla, Samuli (Helsingin yliopisto, 2014)
    Microtia is a congenital malformation that is characterized by variation in severity and its association with other anomalies. Microtia may be a clinical sign of certain syndromes. A typical microtia patient has such a visible malformation that reconstructive surgery of the auricle is desired. In addition to the malformed auricle, both the ear canal and middle ear are usually anomalous causing considerable hearing impairment. This thesis identifies the characteristics of microtia in the Finnish population and detects the existence of familial (hereditary) microtia in Finland. The first learning curve study of reconstructive surgery for microtia is presented. In addition, we have studied the association between auricular malformations and orofacial clefts. The study population for phenotypic characterization consisted of 190 patients referred for reconstruction of the auricle. Of this population, 109 patients were involved in the hereditary study. The learning curve study is based on 51 microtia reconstructions. The study of auricular malformations and clefts includes 100 patients. These studies show that the characteristics of microtia in Finland are for the most part similar to other populations, but there is a high variation in prevalences in different populations. The overall global prevalence is around 2.1/10 000 births compared to 4.3/10 000 in Finland. The proportion of familial microtia in the Finnish population is over 20% and the mode of inheritance seems to be autosomal dominant with incomplete penetrance. The learning curve for microtia reconstruction is long and this finding strongly suggests national centralization of treatment. Microtia seems to be the most common ear malformation in cleft patients. The prevalence of microtia increases as the severity of cleft lip increases. This trend was not present in patients with cleft palate only. Improvement in surgical techniques, the development of biocompatible reconstructive materials, and advances in audiological equipment and diagnostic imaging have improved the ways that a patient with microtia is examined and treated.