7 resultados para Google Analytics
em Helda - Digital Repository of University of Helsinki
Resumo:
This thesis describes current and past n-in-one methods and presents three early experimental studies using mass spectrometry and the triple quadrupole instrument on the application of n-in-one in drug discovery. N-in-one strategy pools and mix samples in drug discovery prior to measurement or analysis. This allows the most promising compounds to be rapidly identified and then analysed. Nowadays properties of drugs are characterised earlier and in parallel with pharmacological efficacy. Studies presented here use in vitro methods as caco-2 cells and immobilized artificial membrane chromatography for drug absorption and lipophilicity measurements. The high sensitivity and selectivity of liquid chromatography mass spectrometry are especially important for new analytical methods using n-in-one. In the first study, the fragmentation patterns of ten nitrophenoxy benzoate compounds, serial homology, were characterised and the presence of the compounds was determined in a combinatorial library. The influence of one or two nitro substituents and the alkyl chain length of methyl to pentyl on collision-induced fragmentation was studied, and interesting structurefragmentation relationships were detected. Two nitro group compounds increased fragmentation compared to one nitro group, whereas less fragmentation was noted in molecules with a longer alkyl chain. The most abundant product ions were nitrophenoxy ions, which were also tested in the precursor ion screening of the combinatorial library. In the second study, the immobilized artificial membrane chromatographic method was transferred from ultraviolet detection to mass spectrometric analysis and a new method was developed. Mass spectra were scanned and the chromatographic retention of compounds was analysed using extract ion chromatograms. When changing detectors and buffers and including n-in-one in the method, the results showed good correlation. Finally, the results demonstrated that mass spectrometric detection with gradient elution can provide a rapid and convenient n-in-one method for ranking the lipophilic properties of several structurally diverse compounds simultaneously. In the final study, a new method was developed for caco-2 samples. Compounds were separated by liquid chromatography and quantified by selected reaction monitoring using mass spectrometry. This method was used for caco-2 samples, where absorption of ten chemically and physiologically different compounds was screened using both single and nin- one approaches. These three studies used mass spectrometry for compound identification, method transfer and quantitation in the area of mixture analysis. Different mass spectrometric scanning modes for the triple quadrupole instrument were used in each method. Early drug discovery with n-in-one is area where mass spectrometric analysis, its possibilities and proper use, is especially important.
Resumo:
The feasibility of different modern analytical techniques for the mass spectrometric detection of anabolic androgenic steroids (AAS) in human urine was examined in order to enhance the prevalent analytics and to find reasonable strategies for effective sports drug testing. A comparative study of the sensitivity and specificity between gas chromatography (GC) combined with low (LRMS) and high resolution mass spectrometry (HRMS) in screening of AAS was carried out with four metabolites of methandienone. Measurements were done in selected ion monitoring mode with HRMS using a mass resolution of 5000. With HRMS the detection limits were considerably lower than with LRMS, enabling detection of steroids at low 0.2-0.5 ng/ml levels. However, also with HRMS, the biological background hampered the detection of some steroids. The applicability of liquid-phase microextraction (LPME) was studied with metabolites of fluoxymesterone, 4-chlorodehydromethyltestosterone, stanozolol and danazol. Factors affecting the extraction process were studied and a novel LPME method with in-fiber silylation was developed and validated for GC/MS analysis of the danazol metabolite. The method allowed precise, selective and sensitive analysis of the metabolite and enabled simultaneous filtration, extraction, enrichment and derivatization of the analyte from urine without any other steps in sample preparation. Liquid chromatographic/tandem mass spectrometric (LC/MS/MS) methods utilizing electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) were developed and applied for detection of oxandrolone and metabolites of stanozolol and 4-chlorodehydromethyltestosterone in urine. All methods exhibited high sensitivity and specificity. ESI showed, however, the best applicability, and a LC/ESI-MS/MS method for routine screening of nine 17-alkyl-substituted AAS was thus developed enabling fast and precise measurement of all analytes with detection limits below 2 ng/ml. The potential of chemometrics to resolve complex GC/MS data was demonstrated with samples prepared for AAS screening. Acquired full scan spectral data (m/z 40-700) were processed by the OSCAR algorithm (Optimization by Stepwise Constraints of Alternating Regression). The deconvolution process was able to dig out from a GC/MS run more than the double number of components as compared with the number of visible chromatographic peaks. Severely overlapping components, as well as components hidden in the chromatographic background could be isolated successfully. All studied techniques proved to be useful analytical tools to improve detection of AAS in urine. Superiority of different procedures is, however, compound-dependent and different techniques complement each other.
Resumo:
High quality of platelet analytics requires specialized knowledge and skills. It was applied to analyze platelet activation and aggregation responses in a prospective controlled study of patients with Finnish type of amyloidosis. The 20 patients with AGel amyloidosis displayed a delayed and more profound platelet shape change than healthy siblings and healthy volunteers, which may be related to altered fragmentation of mutated gelsolin during platelet activation. Alterations in platelet shape change have not been reported in association with platelet disorders. In the rare Bernard-Soulier syndrome with Asn45Ser mutation of glycoprotein (GP) IX, the diagnostic defect in the expression of GPIb-IX-V complex was characterized in seven Finnish patients, also an internationally exceptionally large patient series. When measuring thrombopoietin in serial samples of amniotic fluid and cord blood of 15 pregnant women with confirmed or suspected fetal alloimmune thrombocytopenia, the lower limit of detection could be extended. The results approved that thrombopoietin is present already in amniotic fluid. The application of various non-invasive means for diagnosing thrombocytopenia (TP) revealed that techniques for estimating the proportion of young, i.e. large platelets, such as direct measurement of reticulated platelets and the mean platelet size, would be useful for evaluating platelet kinetics in a given patient. Due to different kinetics between thrombopoietin and increase of young platelets in circulation, these measurements may have most predictive value when measured from simultaneous samples. Platelet autoantibodies were present not only in isolated autoimmune TP but also in patients without TP where disappearance of platelets might be compensated by increased production. The autoantibodies may also persist after TP has been cured. Simultaneous demonstration of increased young platelets (or increased mean platelet volume) in peripheral blood and the presence of platelet associated IgG specificities to major glycoproteins (GPIb-IX and GPIIb-IIIa) may be considered diagnostic for autoimmune TP. Measurement of a soluble marker as a sign of thrombin activation and proceeding deterioration of platelet components was applied to analyze the alterations under several stress factors (storage, transportation and lack of continuous shaking under controlled conditions) of platelet products. The GPV measured as a soluble factor in platelet storage medium showed good correlation with an array of other measurements commonly applied in characterization of stored platelets. The benefits of measuring soluble analyte in a quantitative assay were evident.
Kansanterveysongelman synty : Tuberkuloosi ja terveyden hallinta Suomessa ennen toista maailmansotaa
Resumo:
The study focuses on the emergence of tuberculosis as a public health problem and the development of the various methods to counteract it in Finland before the introduction of efficient methods of treatment in the 1940s and 50s. It covers a time period from year 1882 when the tuberculosis bacterium was identified to the 1930s when the early formation of tuberculosis work became established in Finland. During this time there occurred important changes in medicine, public health thinking and methods of personal health care that have been referred to as the bacteriological revolution. The study places tuberculosis prevention in this context and shows how the tuberculosis problem affected the government of health on all these three dimensions. The study is based on foucauldian analytics of government, which is supplemented with perspectives from contemporary science and technology studies. In addition, it utilises a broad array of work in medical history. The central research materials consist of medical journals, official programs and documents on tuberculosis policy, and health education texts. The general conclusions of the study are twofold. Firstly, the ensemble of tuberculosis work was formed from historically diverse and often conflicting elements. The identification of the pathogen was only the first step in the establishment of tuberculosis as a major public health problem. Important were also the attention of the science of hygiene and statistical reasoning that dominated public health thinking in the late 19th century. Furthermore, the adoption of the bacteriological tuberculosis doctrine in medicine, public health work and health education was profoundly influenced by previous understanding of the nature of the illness, of medical work, of the prevention of contagious diseases, and of personal health care. Also the two central institutions of tuberculosis work, sanatorium and dispensary, have heterogeneous origins and multifarious functions. Secondly, bacteriology represented in this study by tuberculosis remodelled medical knowledge and practices, the targets and methods of public health policy, and the doctrine of personal health care. Tuberculosis provided a strong argument for specific causes (if not cures) as well as laboratory methods in medicine. Tuberculosis prevention contributed substantially to the development whereby a comprehensive responsibility for the health of the population and public health work was added to the agenda of the state. Health advice on tuberculosis and other contagious diseases used dangerous bacteria to motivate personal health care and redefined it as protecting oneself from the attacks of external pathogens and strengthening oneself against their effects. Thus, tuberculosis work is one important root for the contemporary public concern for the health of the population and the imperative of personal health care.
Resumo:
Introduction. We estimate the total yearly volume of peer-reviewed scientific journal articles published world-wide as well as the share of these articles available openly on the Web either directly or as copies in e-print repositories. Method. We rely on data from two commercial databases (ISI and Ulrich's Periodicals Directory) supplemented by sampling and Google searches. Analysis. A central issue is the finding that ISI-indexed journals publish far more articles per year (111) than non ISI-indexed journals (26), which means that the total figure we obtain is much lower than many earlier estimates. Our method of analysing the number of repository copies (green open access) differs from several earlier studies which have studied the number of copies in identified repositories, since we start from a random sample of articles and then test if copies can be found by a Web search engine. Results. We estimate that in 2006 the total number of articles published was approximately 1,350,000. Of this number 4.6% became immediately openly available and an additional 3.5% after an embargo period of, typically, one year. Furthermore, usable copies of 11.3% could be found in subject-specific or institutional repositories or on the home pages of the authors. Conclusions. We believe our results are the most reliable so far published and, therefore, should be useful in the on-going debate about Open Access among both academics and science policy makers. The method is replicable and also lends itself to longitudinal studies in the future.
Resumo:
The thesis aims at investigating the local dimension of the EU cohesion policy through the utilization of an alternative approach, which aims at the analysis of discourse and structures of power. The concrete case under analysis is the Interreg IV programme “Alpenrhein-Bodensee-Hochrhein”, which is conducted in the border region between Germany, Switzerland, Austria and the principality of Liechtenstein. The main research question is stated as such: What governmental rationalities can be found at work in the field of EU cross-border cooperation programmes? How is directive action and cooperation envisioned? How coherent are the different rationalities, which are found at work? The theoretical framework is based on a Foucaultian understanding of power and discourse and utilizes the notion of governmentalities as a way to de-stabilize the understanding of directive action and in order to highlight the dispersed and heterogeneous nature of governmental activity. The approach is situated within the general field of research on the European Union connected to basic conceptualisations such as the nature of power, the role of discourse and modes of subjectification. An approach termed “analytics of government”, based on the work of researchers like Mitchell Dean is introduced as the basic framework for the analysis. Four dimensions (visiblities, subjectivities, techniques/practices, problematisations) are presented as a set of tools with which governmental regimes of practices can be analysed. The empirical part of the thesis starts out with a discussion of the general framework of the European Union's cohesion policy and places the Interreg IV Alpenrhein-Bodensee-Hochrhein programme in this general context. The main analysis is based on eleven interviews which were conducted with different individuals, participating in the programme on different levels. The selection of interview partners aimed at maximising heterogeneity through including individuals from all parts of the programme region, obtaining different functions within the programme. The analysis reveals interesting aspects pertaining to the implementation and routine aspects of work within initiatives conducted under the heading of the EU cohesion policy. The central aspects of an Interreg IV Alpenrhein-Bodensee-Hochrhein – governmentality are sketched out. This includes a positive perception of the work atmosphere, administrative/professional characterisation of the selves and a de-politicization of the programme. Characteristic is the experience of tensions by interview partners and the use of discoursive strategies to resolve them. Negative perceptions play an important role for the specific governmental rationality. The thesis contributes to a better understanding of the local dimension of the European Union cohesion policy and questions established ways of thinking about governmental activity. It provides an insight into the working of power mechanisms in the constitution of fields of discourse and points out matters of practical importance as well as subsequent research questions.
Resumo:
Tämän pro gradu- tutkielman tavoitteena oli löytää kuluttajien palvelukokemukseen vaikuttavat tekijät lastenvaatteiden- ja tarvikkeiden -verkkokaupassa. Empiirinen tutkimus lähestyi aihetta netnografian avulla. Aineistoksi tähän tutkielmaan valittiin sosiaalisen median keskustelut. Tutkimuksen teoreettinen osa muodostui kolmesta aiheesta: verkko-ostamisesta ja palvelun laadusta, sosiaalisesta mediasta sekä word-of-mouth-viestinnästä. Verkko-ostamisessa käsiteltiin ostamisen eri vaiheet, kuluttajien motivaatiot verkosta ostamiseen, sekä siihen liittyvät riskit ja tarkasteltiin sähköisen palvelun laatua. Sosiaalinen media-luku kertoi sosiaalisen median käytöstä sekä eri medioista. Word-of-mouth-viestintä esitteli perinteisen word-of-mouth-viestinnän lisäksi sähköisen WOM-viestinnän ulottuvuudet. Empiirinen tutkimus oli laadullinen ja se toteutettiin netnografisesti. Netnografia on etnografiaan perustuva menetelmä, jota käytetään internet-aineistoissa. Aineiston analysoinnissa käytettiin teemoittelua. Aihetta lähestyttiin faktanäkökulmasta, eli tutkimuksessa oltiin kiinnostuneita niistä tosiasioista joita keskustelijat kertoivat. Aineisto kerättiin perhe-aiheisten lehtien keskustelupalstoilta sekä blogeista Google-haun avulla. Sosiaalisen median keskustelut valittiin aineistoksi, koska niistä uskottiin saatavan kaikkein totuudenmukaisinta tietoa, johon tutkijan kysymyksen asettelu ei vaikuta. Spontaanit keskustelut antavat erilaista tietoa kuin suoran kysymyksen vastaukset. Tutkimuksen tuloksena löytyi seitsemän teemaa, joita keskusteluissa käsiteltiin. Nämä ovat toimitus, palvelu, palautus ja normalisointi, ulkoasu ja toimivuus, hinta, maksaminen sekä tuotteet ja valikoima. Sen sijaan teorian pohjalta odotettavissa olleet turvallisuus ja yksityisyys eivät tulleet aineistosta lainkaan esiin. Erityisen huonona palveluna asiakkaat pitivät varastosaldojen paikkansapitämättömyyttä, hitaita toimituksia sekä epäystävällistä palvelua. Hyvää palvelua olivat nopeat toimitukset sekä yksilöllinen palvelu ja reklamaatioiden hyvä hoito.