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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Identifikation von Lungentumoren aus der Atemluft von Patienten durch Einsatz einer massenspektroskopisch-basierten Messmethode / Breath Analysis for non-invasive Lung Cancer Diagnostic

Kolmer, Veronika January 2014 (has links) (PDF)
Lungenkrebs ist die führende Todesursache unter den Krebstodesfällen. Vor allem in späten Stadien diagnostizierter Lungenkrebs ist schwer zu behandeln und mit einer schlechten Prognose vergesellschaftet. Daher ist es wünschenswert, die Tumorerkrankung möglichst früh zu diagnostizieren und idealerweise in einem Screening-Test finden zu können. In der hier vorliegenden Studie wollten wir die Frage klären, ob ein von der Firma Sony neu entwickeltes Messverfahren SonyNose-G2_SN8 für die Untersuchung von Atemluft und für die Diagnose von Lungentumoren geeignet ist. Für die Studie wurden Atemproben von insgesamt 124 Probanden gesammelt, davon 65 gesunde Studienteilnehmer, 43 Patienten mit histologisch gesichertem Lungenkrebs, 10 Patienten mit COPD und 6 Studienteilnehmern mit nicht lungenkrebsspezifischen Raumforderungen. Die Atemproben wurden innerhalb von 20 Minuten nach Probennahme analysiert. Als Referenz zur getesteten Atemprobe wurde ein Luftgemisch aus gereinigter Luft mit 50%-iger Luftfeuchtigkeit verwendet. Technisch handelt es sich bei der Auswertung um eine gaschromathographische Prüfmethode. Außerdem wurden zusätzliche Atemproben von den Patienten bzw. Probanden gesammelt, um diese mittels GC-MS-Messungen auf ihre volatilen organischen Bestandteile hin zu überprüfen. In den GC-MS-Untersuchungen der Atemproben konnten 263 verschiedene chemische Verbindungen identifiziert werden. Davon konnten 20 Substanzen ermittelt werden, die sich signifikant zwischen der Gruppe „Gesund“ und der Gruppe „Lungenkrebs“ unterschieden. Diese Substanzen könnten sich folglich als Marker für den Lungenkrebs eignen. Weitere Untersuchungen sind zur Überprüfung dieser Hypothese jedoch erforderlich. Nicht zuletzt aufgrund von Problemen mit der Stabilität einzelner Sensoren, war es mit der SonyNose-G2_SN8 nicht möglich, zwischen Lungenkrebs-Patienten, Patienten mit COPD und gesunden Probanden zu unterscheiden. Das getestete Gerät eignet sich also nicht für das Lungenkrebs-Screening im klinischen Einsatz. Auch nach der hier vorliegenden Untersuchung bleibt offen, ob Analyseverfahren zur Atemluftdiagnostik als Screening-Methode zur Früherkennung von Lungenkrebs grundsätzlich geeignet sind. Der Einsatz der gaschromatographischen-massenspektrometrischen Untersuchungsmethode ist für die Routinediagnostik derzeit noch zu zeitaufwendig und zu teuer. Die Identifikation möglicher krebsspezifischer volatiler organischer Verbindungen in der Atemluft von Patienten bleibt für die Forschung weiterhin eine offene und vielversprechende Thematik. / Lung cancer (LC) is the leading cause of cancer death worldwide. Results of therapeutic interventions are not satisfying because the disease is diagnosed in an advanced stage in more than 50% of the patients. Early diagnosis is limited by the fact that the disease usually develops asymptomatically and no screening methods are available. Previous studies have shown correlations between the chemical composition of the exhaled breath of an individual and the presence of LC. The Sony Materials Science Laboratory developed the "electronic nose" SonyNose-G2_SN8 for breath analysis that was tested in a clinical study to evaluate its suitability for LC diagnosis. The SonyNose was tested in a prospective clinical study (proof of concept study). The study was approved by the Etics committee of the University of Tuebingen [project 010/2012BO1). Breath samples from patients with COPD or suspected LC and from healthy individuals were collected. Inclusion criteria were males and females, aged 18-80 yrs, and signed informed consent. Exclusion criteria were suspected or confirmed malignant disease other than lung cancer, previous thoracic surgery and any medical interventions at the chest or the airways within the preceding 14 days. The study participants were classified into four groups: Group A- healthy; Group B-lung cancer; Group C-COPD; Group D-non malignant pulmonary nodule. The decision whether a patient was assigned to the cancer group B was made on the basis of histology of a tumour biopsy or the resected tumour after breath sample analysis. Breath samples were collected in gas sampling bulbs ("gas mouse") provided by Sony. Two gas mice were obtained per person. Reference bulbs were filled with a standardized gas. Additionally, cylindrical glass tubes that have been applied in a successful previous study of Prof. Walles were used for breath sampling. The gas mice were analyzed within 20 min at the Schillerhoehe Hospital using the SonyNose. The glass tubes were stored up and analyzed by gas-chromatography and mass spectrometry (GC-MS) at the Sony Materials Science Laboratory. Altogether, 124 participants were enrolled: 65 healthy individuals (group A), 43 patients with histologically confirmed LC (group B), 10 patients with COPD (group C) and 6 patients with non malignant pulmonary nodules. Breath sample analysis using the SonyNose revealed an instability of the sensor array. Some sensors had to be replaced in the course of the experiments. Intra-individual controls that were performed by testing the same patient repeatedly showed a very high intra-individual variation of the sensor signal and a very low reproducibility. GC-MS analysis were performed in only 27 individuals, because the R&D agreement was cancelled in the course of the study (Group A:9; Group B:11; Group C:1; Group D:6). In the analyzed breath samples, 263 different compounds were identified. In Group B 20 compounds showed a different distribution pattern than in other groups. Of these, 6 have been described as LC associated in previous studies. The small number of tested individuals restricts a conclusive assessment of the generated data. The SonyNose-G2_SN8 is not suitable for a clinical breath sample analysis in the technical configuration tested in our study. GC-MS measurements revealed 20 potential candidates for LC specific markers in the breath of patients. However, the small number of tested individuals limits the validity of our analysis.
12

Jämförelse av metoder för peroxidbestämningar i bränslen : A comparison of methods for determination of peroxide content in fuel

Ly, Becky January 2010 (has links)
<p>New energy resources that can replace petroleum diesel are needed and biodiesel may be an excellent substitute. During storage and use, biodiesel can oxidize and form peroxides, leading to degradation of the fuel. It is therefore important to determine the peroxide content of the fuel. In this thesis the triphenylphosphine method, which involves GC-MS analysis has been compared to the standard iodometric method which involves titration with sodium thiosulfate. Working standards were made to see how well the iodometric method worked and also in order to make a calibration curve in GC-MS. Aged samples were then analyzed. The results showed that both methods gave good linearity and repeatability with limits of detection (LOD) and quantification (LOQ) of 0,06 mM and 0 17-0,65 mM respectively. However, the iodometric method seemed more circumstantial since it needed a lot of solvents and different reagents. The triphenylphosphine method was on contrary very simple to use and did not require too much preparation work. The latter also showed better reproducibility. In conclusions, both methods can be used in evaluating the peroxide content of biodiesel, but the triphenylphosphine method has the advantages of higher simplicity and better reproducibility.</p>
13

Compound specific and enantioselective determination of 2- and 3-hydroxy fatty acids in food

Jenske, Ramona January 2009 (has links)
Zugl.: Hohenheim, Univ., Diss., 2009
14

Shale characterization using TGA, Py-GC-MS, and NMR

Gips, Jameson Parker 03 February 2015 (has links)
Many of the current analytical techniques originally developed to characterize conventional reservoir rocks and fluid cannot adequately measure shale and source rocks. An example of this is Retort, where it is not feasible to get sufficient fluid from source rock to make useful measurements. The primary interest of this thesis is the exploration of other analytical techniques, two of which are previously unused in the oil and gas industry. These are Thermal Gravimetric Analysis (TGA), Pyrolysis-Gas Chromatography-Mass Spectrometry (Py-GC-MS), and Nuclear Magnetic Resonance (NMR). The techniques proposed offer valuable insight into the properties of the rock. TGA gives accurate weight of a sample as temperature is increased, Py-GC-MS is useful for identifying exact molecules in vaporized fluid, and NMR can be used to characterize viscosity and hydrocarbon chain length. The methods using these techniques can be utilized to further confirm mineralogy of a sample, identify the fluid constituents and quantify their weight, analyze changes in a sample between two different states, and calculate the free fluid saturations of oil and gas in shales. Procedures and results for each of these are presented in this thesis to show methodology and give the reader an idea of its useful applications. / text
15

Development and Validation of a Novel Assay to Quantify D-Limonene in Human Adipose Biopsies

Miller, Jessica Anne January 2007 (has links)
d-Limonene is a lipid-soluble bioactive food component found in citrus peel. It has demonstrated strong chemopreventive effects in rodent mammary, gastric, skin, liver, and lung cancers and is correlated with a significantly reduced risk for human squamous cell skin carcinoma. Because d-limonene is fat-soluble, it may have enhanced chemopreventive activity in fatty tissues such as breast. No previous methodology to quantify d-limonene in the adipose had been developed which significantly limited d-limonene tissue distribution research. For this research, an assay to extract d-limonene from adipose tissue and quantify with GC/MS was developed and validated. Linear calibration curves were established over the range of 0.0-2,526 ng d-limonene. Extraction recovery was 80%. Satisfactory within day precision (RSD 6.75 to 9.56%) and accuracy (% difference of 2-4%) were achieved. This sensitive, accurate, and precise assay to quantify d-limonene in adipose can be used for future human or animal fatty tissue deposition studies.
16

Development of a Method for GC/MS Analysis of PAHs and Alkylated PAHs for Use in Characterization and Source Identification of PAH Contaminated Sites

Vestlund, Hanne January 2014 (has links)
Polycyclic aromatic hydrocarbons (PAHs) are toxic and carcinogenic environmental contaminants originating from different sources; petrogenic, pyrogenic or biogenic. Depending on the source of contamination there will be different ratios of PAHs and the effects on the environment will differ. Petrogenic sources will be higher in concentration of alkyl substituted PAHs (APAHs) while pyrogenic sources will be higher in parent PAHs. In the present study a GC/MS method was developed to separate and calibrate PAHs, dibenzothiophenes and alkyl substituted PAHs in a mix containing 49 standards. The method was able to differentiate between PAHs and APAHs with the same mass number; up to six different compounds with the same mass number was separated. The developed method was used to analyse six different soil samples from various contamination sites. PAHs, APAHs and dibenzothiophenes were identified and quantified in all samples. In order to establish the source of contamination, the distribution pattern, the ratio between different PAHs, and the ratio between APAHs and parent PAHs were used. There was a higher ratio of APAHs/PAHs and a lower ratio between the parent PAHs in the soil samples from sites contaminated with oils compared to the other samples, indicating petrogenic source. / Polycykliska aromatiska kolväten (PAH) är giftiga och cancerframkallande miljögifter som härstammar från olika källor; petrogena, pyrogena eller biogena. Olika föroreningskällor kommer att ha olika förhållanden av PAH och effekterna på miljön kommer att skilja. Petrogena källor innehåller högre koncentrationer av alkylsubstituerade PAH (APAH) medan pyrogena källor kommer att ha högre koncentration av PAH. I denna studie har en GC/MS-metod utvecklats för att separera och kalibrera PAH, dibensotiofener och alkylsubstituerade PAH i en blandning innehållande 49 standarder. Metoden kunde skilja mellan PAH och alkylsubstituerade PAH med samma masstal; upp till sex olika föreningar med samma masstal särskildes. Den utvecklade metoden användes för att analysera sex olika jordprover från olika föroreningsplatser. PAH, APAH och dibensotiofener identifierades och kvantifieras i samtliga prover. För att fastställa föroreningskällan användes fördelningsmönstret för APAH och PAH, förhållandet mellan olika PAH och ration mellan APAH och PAH. Det fanns en högre kvot APAH/PAH i jordprover från områden som var förorenade med olja, vilket indikerar på petrogena föroreningskällor.
17

Identifizierung und Quantifizierung von Verbindungen mit östrogener Wirkung im Abwasser

Spengler, Peter. January 2001 (has links)
Stuttgart, Univ., Diss., 2001.
18

Entwicklung und Anwendung von Methoden zur Erfassung von Pyrrolizidinalkaloiden in Honig und Pollen

Kempf, Michael January 2009 (has links)
Würzburg, Univ., Diss., 2009. / Zsfassung in engl. Sprache.
19

Amino acid analysis in biological fluids by GC-MS

Kaspar, Hannelore January 2009 (has links)
Regensburg, Univ, Diss., 2009.
20

Identifizierung und Quantifizierung von Verbindungen mit östrogener Wirkung im Abwasser

Spengler, Peter. Unknown Date (has links) (PDF)
Universiẗat, Diss., 2001--Stuttgart.

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