753 resultados para Uppsala universitet.


Relevância:

30.00% 30.00%

Publicador:

Resumo:

The Uppsala school of Axel Hägerström can be said to have been the last genuinely Swedish philosophical movement. On the other hand, the Swedish analytic tradition is often said to have its roots in Hägerström s thought. This work examines the transformation from Uppsala philosophy to analytic philosophy from an actor-based historical perspective. The aim is to describe how a group of younger scholars (Ingemar Hedenius, Konrad Marc-Wogau, Anders Wedberg, Alf Ross, Herbert Tingsten, Gunnar Myrdal) colonised the legacy of Hägerström and Uppsala philosophy, and faced the challenges they met in trying to reconcile this legacy with the changing philosophical and political currents of the 1930s and 40s. Following Quentin Skinner, the texts are analysed as moves or speech acts in a particular historical context. The thesis consists of five previously published case studies and an introduction. The first study describes how the image of Hägerström as the father of the Swedish analytic tradition was created by a particular faction of younger Uppsala philosophers who (re-) presented the Hägerströmian philosophy as a parallel movement to logical empiricism. The second study examines the confrontations between Uppsala philosophy and logical empiricism in both the editorial board and in the pages of Sweden s leading philosophical journal Theoria. The third study focuses on how the younger generation redescribed Hägerströmian legal philosophical ideas (Scandinavian Legal Realism), while the fourth study discusses how they responded to the accusations of a connection between Hägerström s value nihilistic theory and totalitarianism. Finally, the fifth study examines how the Swedish social scientist and Social Democratic intellectual Gunnar Myrdal tried to reconcile value nihilism with a strong political programme for social reform. The contribution of this thesis to the field consists mainly in a re-evaluation of the role of Uppsala philosophy in the history of Swedish philosophy. From this perspective the Uppsala School was less a collection of certain definite philosophical ideas than an intellectual legacy that was the subject of fierce struggles. Its theories and ideas were redescribed in various ways by individual actors with different philosophical and political intentions.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This Master's thesis examines two opposite nationalistic discourses on the revolution of Zanzibar. Chama cha Mapinduzi (CCM), the party in power since the 1964 revolution defends its revolutionary and "African" heritage in the current multi-party system. New nationalists, including among others the main opposition party Civic United Front (CUF), question both the 1964 revolution and the post-revolution period and blame CCM for empty promises, corruption and ethnic discrimination. This study analyzes the role of a significant historical event in the creation of nationalistic ideology and national identity. The 1964 revolution forms the nucleus of various debates related to the history of Zanzibar: slavery, colonialism, racial discrimination and political violence. Representations of these Social constructivist principles form the basis of this study, and central concepts in the theoretical framework are nationalism, national identity, ethnicity and race. I use critical discourse analysis as my research method, lean on the work by Teun A. van Dijk and Norman Fairclough as the most significant researchers in this field. I examine particularly the ways in which linguistic methods, such as stereotypes and metaphors are used to form in- and out-groups ("us" vs. "others"). My material, both in Swahili and English, was collected mainly in Tanzania in the fall of 2007 and from online sources in the spring of 2009. It includes publications by the Zanzibari government between the years of 1964-2000 (12), official speeches for the Revolution Day or the Union Day (12), articles from Tanzanian newspapers from the 1990s until the year of 2009 (15), memoirs and political pamphlets (10), blog posts and opinion pieces from four different websites (8), and interviews or personal communication in Zanzibar, Dar es Salaam and Uppsala (8). Nationalistic rhetoric often creates enemy images by using binary good-bad oppositions. Both discourses in this study build identities on the basis of "otherness" and exclusion, with the intent of emphasizing the particularity of the own group and excluding "evilness" outside the own reference group. These opposite views on the 1964 revolution as the main axis of the history of Zanzibar build different portraits of the nation and Zanzibari-ness (Uzanzibari). CCM still relies on the pre-revolutionary enemy images of Arabs as selfish rulers and cruel slave traders. For CCM, Zanzibar is primarily an "African" nation and a part of Tanzania which is threatened by "Arabs", the outsiders. In contrast, the new nationalists stress the long history of Zanzibar as multi-racial, cosmopolitan and formerly independent country which has its own, separate culture and identity from mainland Tanzanians. Heshima, honour/respect, one of the basic values of Swahili culture, occupies a central role in both discourses: the main party emphasizes that the revolution returned "heshima" to the Zanzibari Africans after centuries of humiliation, whereas the new nationalists claim that ever since the revolution all "non-Africans" have been humiliated and lost their "heshima". According to the new nationalists, true Zanzibari values which include tolerance and harmony between different "races" were lost when the "foreign" revolutionaries arrived from the mainland. Consequently, they see the 1964 revolution as Tanganyikan colonialism which began with the help of Western countries, and maintain that this "colonialism" still continues in the violent multi-party elections.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The antinociceptive properties of oxycodone and its metabolites were studied in models of thermal and mechanical nociception and in the spinal nerve ligation (SNL) model of neuropathic pain in rats. Oxycodone induced potent antinociception after subcutaneous (s.c.) administration in all models of nociception used in rats compared with morphine, methadone and its enantiomers. In the SNL model of neuropathic pain in rats, oxycodone produced dose dependent antinociception after s.c. administration. The antinociceptive effects of s.c. oxycodone were antagonized by naloxone but not by nor-binaltorphimine (Nor-BNI) a selective κ-opioid receptor antagonist indicating that the antinociceptive properties of oxycodone are predominantly μ-opioid receptor-mediated. The antinociceptive activity of oxymorphone, noroxycodone, and noroxymorphone, oxidative metabolites of oxycodone, were studied to determine their role in the oxycodone-induced antinociception in the rat. Of the metabolites of oxycodone s.c. administration of oxymorphone produced potent thermal and mechanical antinociception. Noroxycodone had a poor antinociceptive effect and noroxymorphone was inactive. Oxycodone produced naloxone-reversible antinociception after intrathecal (i.t) administration with a poor potency compared with morphine and oxymorphone. This seems to be related to the low efficacy and potency of oxycodone to stimulate μ-opioid receptor activation in the spinal cord in μ-opioid receptor agonist-stimulated (GTP)γ[S] autoradiography, compared with morphine and oxymorphone. All metabolites studied were more potent than oxycodone after i.t. administration. I.t. noroxymorphone induced a significantly longer lasting antinociceptive effect compared with the other drugs studied. The role of cytochrome P450 (CYP) 2D6-mediated metabolites on the analgesic activity of oxycodone in humans was studied by blocking the CYP2D6-mediated metabolism of oxycodone with paroxetine. Paroxetine co-administration had no effect on the analgesic effect of oxycodone compared with placebo in chronic pain patients, indicating that oxycodone-induced analgesia and adverse-effects are not dependent of the CYP2D6-mediated metabolism in humans. Although oxycodone has many pharmacologically active metabolites, they seem to have an insignificant role in oxycodone-induced antinociception in humans and rats.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this paper both documentary and natural proxy data have been used to improve the accuracy of palaeoclimatic knowledge in Finland since the 18th century. Early meteorological observations from Turku (1748-1800) were analyzed first as a potential source of climate variability. The reliability of the calculated mean temperatures was evaluated by comparing them with those of contemporary temperature records from Stockholm, St. Petersburg and Uppsala. The resulting monthly, seasonal and yearly mean temperatures from 1748 to 1800 were compared with the present day mean values (1961-1990): the comparison suggests that the winters of the period 1749-1800 were 0.8 ºC colder than today, while the summers were 0.4 ºC warmer. Over the same period, springs were 0.9 ºC and autumns 0.1 ºC colder than today. Despite their uncertainties when compared with modern meteorological data, early temperature measurements offer direct and daily information about the weather for all months of the year, in contrast with other proxies. Secondly, early meteorological observations from Tornio (1737-1749) and Ylitornio (1792-1838) were used to study the temporal behaviour of the climate-tree growth relationship during the past three centuries in northern Finland. Analyses showed that the correlations between ring widths and mid-summer (July) temperatures did not vary significantly as a function of time. Early (June) and late summer (August) mean temperatures were secondary to mid-summer temperatures in controlling the radial growth. According the dataset used, there was no clear signature of temporally reduced sensitivity of Scots pine ring widths to mid-summer temperatures over the periods of early and modern meteorological observations. Thirdly, plant phenological data with tree-rings from south-west Finland since 1750 were examined as a palaeoclimate indicator. The information from the fragmentary, partly overlapping, partly nonsystematically biased plant phenological records of 14 different phenomena were combined into one continuous time series of phenological indices. The indices were found to be reliable indicators of the February to June temperature variations. In contrast, there was no correlation between the phenological indices and the precipitation data. Moreover, the correlations between the studied tree-rings and spring temperatures varied as a function of time and hence, their use in palaeoclimate reconstruction is questionable. The use of present tree-ring datasets for palaeoclimate purposes may become possible after the application of more sophisticated calibration methods. Climate variability since the 18th century is perhaps best seen in the fourth paper study of the multiproxy spring temperature reconstruction of south-west Finland. With the help of transfer functions, an attempt has been made to utilize both documentary and natural proxies. The reconstruction was verified with statistics showing a high degree of validity between the reconstructed and observed temperatures. According to the proxies and modern meteorological observations from Turku, springs have become warmer and have featured a warming trend since around the 1850s. Over the period of 1750 to around 1850, springs featured larger multidecadal low-frequency variability, as well as a smaller range of annual temperature variations. The coldest springtimes occurred around the 1840s and 1850s and the first decade of the 19th century. Particularly warm periods occurred in the 1760s, 1790s, 1820s, 1930s, 1970s and from 1987 onwards, although in this period cold springs occurred, such as the springs of 1994 and 1996. On the basis of the available material, long-term temperature changes have been related to changes in the atmospheric circulation, such as the North Atlantic Oscillation (February-June).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Can war be justified? Expressions of opinions by the general assemblies of the World Council of Churches on the question of war as a method of settling conflicts. The purpose of this study is to describe and analyse the expressions of opinions recorded in the documents of the general assemblies of the WCC during the Cold War period from 1948 to 1983 on the use of war as a method of settling international and national conflicts. The main sources are the official reports of the WCC´s assemblies during the years 1948 to 1983. This study divides the discussions into three periods. The first period (1949-1968) is dominated by the pressures arising from the Second World War. Experiences of the war led the assemblies of the WCC to the conclusion that modern warfare as a method of settling conflicts should be rejected. Modern war was contrary to God´s purposes and the whole meaning of creation, said the assembly. Although the WCC rejected modern war, it left open the possibility of conflict where principles of just war may be practised. The question of war was also linked to the state and its function, which led to the need to create a politically neutral doctrine for the socio-ethical thinking of churches and of the WCC itself. The doctrine was formulated using the words "responsible society". The question of war and socio-ethical thinking were on the WCC`s agenda throughout the first period. Another issue that had an influence on the first period was the increasing role of Third World countries. This new dimension also brought new aspects to the question of war and violence. The second period (1968-1975) presented greater challenges to the WCC, especially in traditional western countries. The Third World, political activity in the socialist world and ideas of revolution were discussed. The WCC`s fourth Assembly in Uppsala was challenged by these new ideas of revolution. The old doctrine of "responsible society" was seen by many participants as unsuitable in the modern world, especially for Third World countries. The situation of a world governed by armaments, causing social and economic disruption, was felt by churches to be problematic. The peace movement gathered pace and attention. There was pressure to see armed forces as an option on the way to a new world order. The idea of a just war was challenged by that of just revolution. These ideas of revolution did not receive support from the Uppsala Assembly, but they pressured the WCC to reconsider its socio-ethical thinking. Revolution was seen as a possibility, but only when it could be peaceful. In the Nairobi Assembly the theme of just, participatory and sustainable society provided yet another viewpoint, dealing with the life of the world and its problems as a whole. The third period (1975-1983) introduced a new, alternative doctrine the "JPIC Process", justice, peace and the integrity of creation for social thinking in the WCC. The WCC no longer wanted to discuss war or poverty as separate questions, but wanted to combine all aspects of life to see the impact of an arms-governed world on humankind. Thus, during the last period, discussions focused on socio-ethical questions, where war and violence were only parts of a larger problem. Through the new JPIC Process, the WCC`s Assembly in Vancouver looked for a new world, one without violence, in all aspects of life. Despite differing opinions in socio-ethical thinking, the churches in the WCC agreed that modern warfare cannot be regarded as acceptable or just. The old idea of a "just war" still had a place, but it was not seen by all as a valid principle. As a result the WCC viewed war as a final solution to be employed when all other methods had failed. Such a war would have to secure peace and justice for all. In the discussions there was a strong political east-west divide, and, during the last two decades, a north-south divide as well. The effect of the Cold War was obvious. In the background to the theological positions were two main concepts namely the idea of God´s activity in man´s history through the so-called regiments and, the concept of the Kingdom of God on Earth.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Cyclosporine is an immunosuppressant drug with a narrow therapeutic index and large variability in pharmacokinetics. To improve cyclosporine dose individualization in children, we used population pharmacokinetic modeling to study the effects of developmental, clinical, and genetic factors on cyclosporine pharmacokinetics in altogether 176 subjects (age range: 0.36–20.2 years) before and up to 16 years after renal transplantation. Pre-transplantation test doses of cyclosporine were given intravenously (3 mg/kg) and orally (10 mg/kg), on separate occasions, followed by blood sampling for 24 hours (n=175). After transplantation, in a total of 137 patients, cyclosporine concentration was quantified at trough, two hours post-dose, or with dose-interval curves. One-hundred-four of the studied patients were genotyped for 17 putatively functionally significant sequence variations in the ABCB1, SLCO1B1, ABCC2, CYP3A4, CYP3A5, and NR1I2 genes. Pharmacokinetic modeling was performed with the nonlinear mixed effects modeling computer program, NONMEM. A 3-compartment population pharmacokinetic model with first order absorption without lag-time was used to describe the data. The most important covariate affecting systemic clearance and distribution volume was allometrically scaled body weight i.e. body weight**3/4 for clearance and absolute body weight for volume of distribution. The clearance adjusted by absolute body weight declined with age and pre-pubertal children (< 8 years) had an approximately 25% higher clearance/body weight (L/h/kg) than did older children. Adjustment of clearance for allometric body weight removed its relationship to age after the first year of life. This finding is consistent with a gradual reduction in relative liver size towards adult values, and a relatively constant CYP3A content in the liver from about 6–12 months of age to adulthood. The other significant covariates affecting cyclosporine clearance and volume of distribution were hematocrit, plasma cholesterol, and serum creatinine, explaining up to 20%–30% of inter-individual differences before transplantation. After transplantation, their predictive role was smaller, as the variations in hematocrit, plasma cholesterol, and serum creatinine were also smaller. Before transplantation, no clinical or demographic covariates were found to affect oral bioavailability, and no systematic age-related changes in oral bioavailability were observed. After transplantation, older children receiving cyclosporine twice daily as the gelatine capsule microemulsion formulation had an about 1.25–1.3 times higher bioavailability than did the younger children receiving the liquid microemulsion formulation thrice daily. Moreover, cyclosporine oral bioavailability increased over 1.5-fold in the first month after transplantation, returning thereafter gradually to its initial value in 1–1.5 years. The largest cyclosporine doses were administered in the first 3–6 months after transplantation, and thereafter the single doses of cyclosporine were often smaller than 3 mg/kg. Thus, the results suggest that cyclosporine displays dose-dependent, saturable pre-systemic metabolism even at low single doses, whereas complete saturation of CYP3A4 and MDR1 (P-glycoprotein) renders cyclosporine pharmacokinetics dose-linear at higher doses. No significant associations were found between genetic polymorphisms and cyclosporine pharmacokinetics before transplantation in the whole population for which genetic data was available (n=104). However, in children older than eight years (n=22), heterozygous and homozygous carriers of the ABCB1 c.2677T or c.1236T alleles had an about 1.3 times or 1.6 times higher oral bioavailability, respectively, than did non-carriers. After transplantation, none of the ABCB1 SNPs or any other SNPs were found to be associated with cyclosporine clearance or oral bioavailability in the whole population, in the patients older than eight years, or in the patients younger than eight years. In the whole population, in those patients carrying the NR1I2 g.-25385C–g.-24381A–g.-205_-200GAGAAG–g.7635G–g.8055C haplotype, however, the bioavailability of cyclosporine was about one tenth lower, per allele, than in non-carriers. This effect was significant also in a subgroup of patients older than eight years. Furthermore, in patients carrying the NR1I2 g.-25385C–g.-24381A–g.-205_-200GAGAAG–g.7635G–g.8055T haplotype, the bioavailability was almost one fifth higher, per allele, than in non-carriers. It may be possible to improve individualization of cyclosporine dosing in children by accounting for the effects of developmental factors (body weight, liver size), time after transplantation, and cyclosporine dosing frequency/formulation. Further studies are required on the predictive value of genotyping for individualization of cyclosporine dosing in children.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Aims: To gain insight on the immunological processes behind cow’s milk allergy (CMA) and the development of oral tolerance. To furthermore investigate the associations of HLA II and filaggrin genotypes with humoral responses to early oral antigens. Methods: The study population was from a cohort of 6209 healthy, full-term infants who in a double-blind randomized trial received supplementary feeding at maternity hospitals (mean duration 4 days): cow’s milk (CM) formula, extensively hydrolyzed whey formula or donor breast milk. Infants who developed CM associated symptoms that subsided during elimination diet (n=223) underwent an open oral CM challenge (at mean age 7 months). The challenge was negative in 112, and in 111 it confirmed CMA, which was IgE-mediated in 83. Patients with CMA were followed until recovery, and 94 of them participated in a follow-up study at age 8-9 years. We investigated serum samples at diagnosis (mean age 7 months, n=111), one year later (19 months, n=101) and at follow-up (8.6 years, n=85). At follow-up, also 76 children randomly selected from the original cohort and without CM associated symptoms were included. We measured CM specific IgE levels with UniCAP (Phadia, Uppsala, Sweden), and β-lactoglobulin, α-casein and ovalbumin specific IgA, IgG1, IgG4 and IgG levels with enzyme-linked immunosorbent assay in sera. We applied a microarray based immunoassay to measure the binding of IgE, IgG4 and IgA serum antibodies to sequential epitopes derived from five major CM proteins at the three time points in 11 patients with active IgE-mediated CMA at age 8-9 years and in 12 patients who had recovered from IgE-mediated CMA by age 3 years. We used bioinformatic methods to analyze the microarray data. We studied T cell expression profile in peripheral blood mononuclear cell (PBMC) samples from 57 children aged 5-12 years (median 8.3): 16 with active CMA, 20 who had recovered from CMA by age 3 years, 21 non-atopic control subjects. Following in vitro β-lactoglobulin stimulation, we measured the mRNA expression in PBMCs of 12 T-cell markers (T-bet, GATA-3, IFN-γ, CTLA4, IL-10, IL-16, TGF-β, FOXP3, Nfat-C2, TIM3, TIM4, STIM-1) with quantitative real time polymerase chain reaction, and the protein expression of CD4, CD25, CD127, FoxP3 with flow cytometry. To optimally distinguish the three study groups, we performed artificial neural networks with exhaustive search for all marker combinations. For genetic associations with specific humoral responses, we analyzed 14 HLA class II haplotypes, the PTPN22 1858 SNP (R620W allele) and 5 known filaggrin null mutations from blood samples of 87 patients with CMA and 76 control subjects (age 8.0-9.3 years). Results: High IgG and IgG4 levels to β-lactoglobulin and α-casein were associated with the HLA (DR15)-DQB1*0602 haplotype in patients with CMA, but not in control subjects. Conversely, (DR1/10)-DQB1*0501 was associated with lower IgG and IgG4 levels to these CM antigens, and to ovalbumin, most significantly among control subjects. Infants with IgE-mediated CMA had lower β -lactoglobulin and α-casein specific IgG1, IgG4 and IgG levels (p<0.05) at diagnosis than infants with non-IgE-mediated CMA or control subjects. When CMA persisted beyond age 8 years, CM specific IgE levels were higher at all three time points investigated and IgE epitope binding pattern remained stable (p<0.001) compared with recovery from CMA by age 3 years. Patients with persisting CMA at 8-9 years had lower serum IgA levels to β-lactoglobulin at diagnosis (p=0.01), and lower IgG4 levels to β-lactoglobulin (p=0.04) and α-casein (p=0.05) at follow-up compared with patients who recovered by age 3 years. In early recovery, signal of IgG4 epitope binding increased while that of IgE decreased over time, and binding patterns of IgE and IgG4 overlapped. In T cell expression profile in response to β –lactoglobulin, the combination of markers FoxP3, Nfat-C2, IL-16, GATA-3 distinguished patients with persisting CMA most accurately from patients who had become tolerant and from non-atopic subjects. FoxP3 expression at both RNA and protein level was higher in children with CMA compared with non-atopic children. Conclusions: Genetic factors (the HLA II genotype) are associated with humoral responses to early food allergens. High CM specific IgE levels predict persistence of CMA. Development of tolerance is associated with higher specific IgA and IgG4 levels and lower specific IgE levels, with decreased CM epitope binding by IgE and concurrent increase in corresponding epitope binding by IgG4. Both Th2 and Treg pathways are activated upon CM antigen stimulation in patients with CMA. In the clinical management of CMA, HLA II or filaggrin genotyping are not applicable, whereas the measurement of CM specific antibodies may assist in estimating the prognosis.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Activation of midbrain dopamine systems is thought to be critically involved in the addictive properties of abused substances. Drugs of abuse increase dopamine release in the nucleus accumbens and dorsal striatum, which are the target areas of mesolimbic and nigrostriatal dopamine pathways, respectively. Dopamine release in the nucleus accumbens is thought to mediate the attribution of incentive salience to rewards, and dorsal striatal dopamine release is involved in habit formation. In addition, changes in the function of prefrontal cortex (PFC), the target area of mesocortical dopamine pathway, may skew information processing and memory formation such that the addict pays an abnormal amount of attention to drug-related cues. In this study, we wanted to explore how long-term forced oral nicotine exposure or the lack of catechol-O-methyltransferase (COMT), one of the dopamine metabolizing enzymes, would affect the functioning of these pathways. We also wanted to find out how the forced nicotine exposure or the lack of COMT would affect the consumption of nicotine, alcohol, or cocaine. First, we studied the effect of forced chronic nicotine exposure on the sensitivity of dopamine D2-like autoreceptors in microdialysis and locomotor activity experiments. We found that the sensitivity of these receptors was unchanged after forced oral nicotine exposure, although an increase in the sensitivity was observed in mice treated with intermittent nicotine injections twice daily for 10 days. Thus, the effect of nicotine treatment on dopamine autoreceptor sensitivity depends on the route, frequency, and time course of drug administration. Second, we investigated whether the forced oral nicotine exposure would affect the reinforcing properties of nicotine injections. The chronic nicotine exposure did not significantly affect the development of conditioned place preference to nicotine. In the intravenous self-administration paradigm, however, the nicotine-exposed animals self-administered nicotine at a lower unit dose than the control animals, indicating that their sensitivity to the reinforcing effects of nicotine was enhanced. Next, we wanted to study whether the Comt gene knock-out animals would be a suitable model to study alcohol and cocaine consumption or addiction. Although previous work had shown male Comt knock-out mice to be less sensitive to the locomotor-activating effects of cocaine, the present study found that the lack of COMT did not affect the consumption of cocaine solutions or the development of cocaine-induced place preference. However, the present work did find that male Comt knock-out mice, but not female knock-out mice, consumed ethanol more avidly than their wild-type littermates. This finding suggests that COMT may be one of the factors, albeit not a primary one, contributing to the risk of alcoholism. Last, we explored the effect of COMT deficiency on dorsal striatal, accumbal, and prefrontal cortical dopamine metabolism under no-net-flux conditions and under levodopa load in freely-moving mice. The lack of COMT did not affect the extracellular dopamine concentrations under baseline conditions in any of the brain areas studied. In the prefrontal cortex, the dopamine levels remained high for a prolonged time after levodopa treatment in male, but not female, Comt knock-out mice. COMT deficiency induced accumulation of 3,4-dihydroxyphenylacetic acid, which increased further under levodopa load. Homovanillic acid was not detectable in Comt knock-out animals either under baseline conditions or after levodopa treatment. Taken together, the present results show that although forced chronic oral nicotine exposure affects the reinforcing properties of self-administered nicotine, it is not an addiction model itself. COMT seems to play a minor role in dopamine metabolism and in the development of addiction under baseline conditions, indicating that dopamine function in the brain is well-protected from perturbation. However, the role of COMT becomes more important when the dopaminergic system is challenged, such as by pharmacological manipulation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The surface properties of solid state pharmaceutics are of critical importance. Processing modifies the surfaces and effects surface roughness, which influences the performance of the final dosage form in many different levels. Surface roughness has an effect on, e.g., the properties of powders, tablet compression and tablet coating. The overall goal of this research was to understand the surface structures of pharmaceutical surfaces. In this context the specific purpose was to compare four different analysing techniques (optical microscopy, scanning electron microscopy, laser profilometry and atomic force microscopy) in various pharmaceutical applications where the surfaces have quite different roughness scale. This was done by comparing the image and roughness analysing techniques using powder compacts, coated tablets and crystal surfaces as model surfaces. It was found that optical microscopy was still a very efficient technique, as it yielded information that SEM and AFM imaging are not able to provide. Roughness measurements complemented the image data and gave quantitative information about height differences. AFM roughness data represents the roughness of only a small part of the surface and therefore needs other methods like laser profilometer are needed to provide a larger scale description of the surface. The new developed roughness analysing method visualised surface roughness by giving detailed roughness maps, which showed local variations in surface roughness values. The method was able to provide a picture of the surface heterogeneity and the scale of the roughness. In the coating study, the laser profilometer results showed that the increase in surface roughness was largest during the first 30 minutes of coating when the surface was not yet fully covered with coating. The SEM images and the dispersive X-ray analysis results showed that the surface was fully covered with coating within 15 to 30 minutes. The combination of the different measurement techniques made it possible to follow the change of surface roughness and development of polymer coating. The optical imaging techniques gave a good overview of processes affecting the whole crystal surface, but they lacked the resolution to see small nanometer scale processes. AFM was used to visualize the nanoscale effects of cleaving and reveal the full surface heterogeneity, which underlies the optical imaging. Ethanol washing changed small (nanoscale) structure to some extent, but the effect of ethanol washing on the larger scale was small. Water washing caused total reformation of the surface structure at all levels.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Miniaturization of analytical instrumentation is attracting growing interest in response to the explosive demand for rapid, yet sensitive analytical methods and low-cost, highly automated instruments for pharmaceutical and bioanalyses and environmental monitoring. Microfabrication technology in particular, has enabled fabrication of low-cost microdevices with a high degree of integrated functions, such as sample preparation, chemical reaction, separation, and detection, on a single microchip. These miniaturized total chemical analysis systems (microTAS or lab-on-a-chip) can also be arrayed for parallel analyses in order to accelerate the sample throughput. Other motivations include reduced sample consumption and waste production as well as increased speed of analysis. One of the most promising hyphenated techniques in analytical chemistry is the combination of a microfluidic separation chip and mass spectrometer (MS). In this work, the emerging polymer microfabrication techniques, ultraviolet lithography in particular, were exploited to develop a capillary electrophoresis (CE) separation chip which incorporates a monolithically integrated electrospray ionization (ESI) emitter for efficient coupling with MS. An epoxy photoresist SU-8 was adopted as structural material and characterized with respect to its physicochemical properties relevant to chip-based CE and ESI/MS, namely surface charge, surface interactions, heat transfer, and solvent compatibility. As a result, SU-8 was found to be a favorable material to substitute for the more commonly used glass and silicon in microfluidic applications. In addition, an infrared (IR) thermography was introduced as direct, non-intrusive method to examine the heat transfer and thermal gradients during microchip-CE. The IR data was validated through numerical modeling. The analytical performance of SU-8-based microchips was established for qualitative and quantitative CE-ESI/MS analysis of small drug compounds, peptides, and proteins. The CE separation efficiency was found to be similar to that of commercial glass microchips and conventional CE systems. Typical analysis times were only 30-90 s per sample indicating feasibility for high-throughput analysis. Moreover, a mass detection limit at the low-attomole level, as low as 10E+5 molecules, was achieved utilizing MS detection. The SU-8 microchips developed in this work could also be mass produced at low cost and with nearly identical performance from chip to chip. Until this work, the attempts to combine CE separation with ESI in a chip-based system, amenable to batch fabrication and capable of high, reproducible analytical performance, have not been successful. Thus, the CE-ESI chip developed in this work is a substantial step toward lab-on-a-chip technology.