Dissertations / Theses on the topic 'Volatile Biomarkers'
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Parekh, Bhavin. "Volatile biomarkers of blood glucose." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609459.
Full textJohnson, Emmanuel Uche. "Volatile organic compounds: novel potential biomarkers in bladder cancer diagnosis." Thesis, University of Bristol, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.681344.
Full textBond, A. "An investigation of volatile organic compounds as biomarkers for gastrointestinal neoplasia." Thesis, University of Liverpool, 2017. http://livrepository.liverpool.ac.uk/3006172/.
Full textCosta, Carina Filipa Pedrosa da. "Volatile exometabolone analysis of Aspergillus niger and search for molecular biomarkers pattern." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/14864.
Full textFungal infections have greatly increased in risk populations, namely in immunocompromised patients, probabily because the diagnosis of fungal infections is delayed. Microbial metabolomics arises as a powerful feature screening the metabolites produced by microorganisms. It provides information regarding the state of biological organisms which can be used as a diagnostic tool for diseases through fungal metabolites pattern. Thus, this research aimed to in-depth study of the Aspergillus niger exometabolome, in order to establish a targeted metabolomic pattern that characterizes A. niger. A methodology based on headspace-solid phase microextraction combined with comprehensive two-dimensional gas chromatography coupled to mass spectrometry with a high resolution time of flight analyser (HS-SPME/GC×GC-ToFMS) was used. A. niger exometabolome was analysed in different growth conditions: temperature (25 and 37 °C), incubation time (3 and 5 days), and culture medium (solid and liquid medium). A. niger exometabolome included 430 metabolites, distributed over several chemical families, being the major ones alcohols, aldehydes, esters, hydrocarbons, ketones and terpenoids. Differences among volatile metabolites produced under different growth conditions were observed, being the major relative abundance determined for 5 days of growth, at 25 °C, using solid medium. These results indicated the high complexity of A. niger exometabolome. A subset of 44 metabolites, which were present in all previously tested growth conditions, was defined as the A. niger targeted metabolomic pattern. This pattern may be used in detection of fungal infections by this specie and be further exploited to fungal infections diagnosis. Furthermore, this subset of metabolites was compared with samples of Candida albicans (yeast) and Penicillium chrysogenum (filamentous fungi), and Partial Least Squares Discriminant Analysis (PLS-DA) was applied. The results clearly showed that this metabolites subset allowed the distinction between these microorganisms. In order to validate the PLS-DA model, permutation test was applied, and a statistically significant model for 44 metabolites was obtained with a predictive Q2 capability of 0.70 for A. niger. When the subset of compounds were reduced to 16 (obtained by Variables Importance in Projection (VIP) parameter), the obtained model had a predictive Q2 capability of 0.86 for A. niger, which was significantly higher, being more robust than the previous. The decrease of 44 to 16 metabolites, reduced the require analysis time and the conditions used were similar to the conditions used in clinical context, (solid medium, at 25 °C and ca. 1 week). However, in this study was possible to reduce the time for 3 days. In conclusion, these 44 volatile molecular biomarkers could be useful for diagnosis of fungal infections, and they can even be further exploited in clinical context.
As infeções fúngicas têm aumentado bastante em populações de risco, nomeadamente em pacientes imunocomprometidos, provavelmente devido a atrasos no diagnóstico das infeções fúngicas. A metabolómica microbiana surge como um poderoso recurso de triagem dos metabolitos produzidos por microrganismos. Esta fornece informações sobre o estado de organismos biológicos, que podem ser usados como uma ferramenta de diagnóstico para infeções fúngicas através de um padrão de metabolitos fúngicos. Assim, este trabalho teve como objetivo estudar em profundidade o exometaboloma de Aspergillus niger, a fim de estabelecer um padrão metobolómico alvo que caracterize o A. niger. Foi usada uma metodologia baseada em microextração em fase sólida no espaço de cabeça combinada com cromatografia de gás bidimensional abrangente acoplada a espectrometria de massa por tempo de voo (HS-SPME / GC×GC-ToFMS). O exometaboloma de A. niger foi analisado em diferentes condições de crescimento: temperatura (25 e 37 °C), tempo de incubação (3 e 5 dias) e meio de cultura (meio sólido e líquido). O exometaboloma do A. niger incluiu 430 metabolitos, distribuídos em várias famílias químicas, sendo os mais importantes os álcoois, aldeídos, ésteres, cetonas, hidrocarbonetos e terpenos. Observaram-se diferenças entre os metabolitos voláteis produzidos em diferentes condições de crescimento, sendo a maior abundância relativa determinada para os 5 dias de crescimento, a 25 °C, utilizando meio sólido. Estes resultados indicaram a alta complexidade do exometaboloma do A. niger. Um subconjunto de 44 metabolitos, que estavam presentes em todas as condições de crescimento testadas, foi definido como um padrão metabolómico alvo para o A. niger. Este padrão pode ser usado na deteção de infeções fúngicas por esta espécie e ser futuramente explorado para diagnóstico de infeções fúngicas. Além disso, este subconjunto de metabolitos foi comparado com amostras de Candida albicans (levedura) e Penicillium chrysogenum (fungo filamentoso), e a análise discriminante com método dos mínimos quadrados parciais (PLS-DA) foi aplicada. Os resultados mostraram claramente que este subconjunto de metabolitos permitiu distinguir estes microrganismos. Para validar o modelo do PLS-DA, o teste das permutações foi aplicado, e um modelo estatísticamente significante para os 44 metabolitos foi obtido com uma capacidade preditiva Q2 de 0.70 para o A. niger. Quando o subconjunto de compostos foi reduzido para 16 (obtidos pelo parâmetro Importância da Variável na Projeção (VIP)), o modelo obtido teve uma capacidade preditiva Q2 de 0.86 para o A. niger, que foi significantemente superior, sendo mais robusto que o anterior. A diminuição de 44 para 16 metabolitos, reduziu o tempo de análise necessário e as condições utilizadas foram semelhantes às condições utilizadas em contexto clínico, (meio sólido e 25 °C e aproximadamente 1 semana). No entanto, neste estudo, foi possível reduzir o tempo para 3 dias. Em conclusão, estes 44 biomarcadores moleculares voláteis poderão ser úteis para o diagnóstico de infeções fúngicas, e podem ser explorados em contexto clínico.
Ahmed, Iftikhar. "Diagnostic potential of volatile organic compounds as faecal biomarkers in inflammatory bowel disease." Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555660.
Full textTurner, Matthew A. "Boundaries in volatile organic compounds in human breath." Thesis, Loughborough University, 2016. https://dspace.lboro.ac.uk/2134/20274.
Full textJayasena, Demuni Hiruni. "Diagnostic potential of volatile organic compounds and lactoferrin as biomarkers in inflammatory bowel disease." Thesis, University of Bristol, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.617931.
Full textSchmidt, K. "In vitro analysis of volatile organic compounds in search of potential biomarkers of lung cancer." Thesis, University of Salford, 2016. http://usir.salford.ac.uk/40237/.
Full textChippendale, Thomas W. E. "Volatile biomarkers emitted by cell cultures : headspace analysis using selected ion flow tube mass spectrometry, SIFT-MS." Thesis, Keele University, 2012. http://eprints.keele.ac.uk/3724/.
Full textColόn, Crespo Lauren J. "Determination of Human Scent Biomarkers for Race, Ethnicity and Gender." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2442.
Full textKusano, Maiko. "Comparison of Medical and Forensic Profiling Potential of Volatile Biomarkers from Different Biological Specimens from Individuals and Across Populations." FIU Digital Commons, 2010. http://digitalcommons.fiu.edu/etd/307.
Full textNahan, Keaton. "Principal Component Analysis Approach for Determination of Stroke Protein Biomarkers and Modified Atmospheric Pressure Chemical Ionization Source Development for Volatile Analyses." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1491817651627161.
Full textSahlberg, Bo. "Indoor Environment in Dwellings and Sick Building Syndrome (SBS) : Longitudinal Studies." Doctoral thesis, Uppsala universitet, Arbets- och miljömedicin, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-172769.
Full textSchwaiblmair, Michaela Hedwig [Verfasser], and Tobias [Akademischer Betreuer] Fink. "Volatile Biomarker in der Ausatemluft während systemischer Inflammation / Michaela Hedwig Schwaiblmair ; Betreuer: Tobias Fink." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2019. http://d-nb.info/1201346754/34.
Full textDavis, Philip R. N. "The Investigation of Human Scent from Epileptic Patients for the Identification of a Biomarker for Epileptic Seizures." FIU Digital Commons, 2017. https://digitalcommons.fiu.edu/etd/3520.
Full textSchallschmidt, Kristin. "Biomarker in Atemluft." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2017. http://dx.doi.org/10.18452/17800.
Full textA non-invasive breath test for lung cancer detection would be favorable but knowledge on lung cancer specific substances is required. This work aims at the identification of potential lung cancer biomarkers in breath. Volatile organic compounds (VOC) were chosen as targets and a SPME-GC-MS method was developed to analyze the VOC profiles of model systems and real samples. Three lung adenocarcinoma cell lines were investigated in-vitro. The VOC analysis, carried out with 3 different sampling strategies, was influenced by the VOC background of the used disposable culture vessels. Changes in the VOC profiles of cell lines compared to cell-free culture media were obvious: 1-propanol was released by the tumor cells whereas the content of some aldehydes was diminished. The similarity of this model system with real breath samples of lung cancer patients was seen to be insignificant. Consequently, these cell cultures were not suitable for biomarker identification. A gaseous model consisting of humidified synthetic air was developed. It was fortified with 24 target VOC (alkanes, aromatics and oxygenated species) as well as 3 matrix compounds (isoprene, acetone and 2-propanol) dominating patients’ VOC profiles in breath. This model was used for the quality assured quantitative VOC analysis in real breath samples. In cooperation with two hospitals 37 single mixed expiratory breath samples from lung cancer patients and 23 from healthy controls were collected. Applying 1-butanol as an univariate biomarker patients and controls were discriminated with a sensitivity of 92% and a specificity of 78%. Linear discriminant analysis displayed a set of 4 VOC (1-butanol, 2-butanone, 2-pentanone, n-hexanal) with similar sensitivity but higher specificity of 87%. However, these potential biomarkers might rather be a consequence of illness in general.
Grigsby, Claude Curtis. "A Comprehensive Tool and Analytical Pathway for Differential Molecular Profiling and Biomarker Discovery." Wright State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=wright1387540709.
Full textPemassani, Jhansi Kalyani. "Stress responses to wood and wood-derived volatiles using the yeast Saccharomyces cerevisiae as a model system for biological monitoring /." Göttingen : Cuvillier, 2007. http://d-nb.info/985452501/04.
Full textAlzabadi, Hamzeh. "Biomarkers of evaluation of complex environmental exposure : exposure assessment of sewage workers to genotoxicants." Thesis, Nancy 1, 2010. http://www.theses.fr/2010NAN10008/document.
Full textSewage workers are exposed to a wide variety of mixtures of chemicals many were shown to be genotoxicants or carcinogens. The aim of this cross sectional study was to explore integrated biomarkers of exposure and of early effects among sewage workers in order to better assess their carcinogenic risk (Paper I-protocol). Paper II, describes the validation step performed prior to choose the cellular line that meet our objectives. Over 10 months and on weekly basis, we, a) assessed the personal exposure of sewage (n=34) and office (n=30) workers (control group) to polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) in the air of workplaces, b) evaluated the genotoxicity of organic urine extracts by in vitro comet and micronucleus assays on Hep G2 cells, c) assessed the DNA oxidative stress by the 24h urinary 8 oxo 2' deoxyguanosine (8 oxodG) (Paper III). The tests showed greater genotoxicity in the urine extracts of sewage workers (P<0.001). The 24hr urinary 8 oxodG mean level in sewage workers was higher (nonsignificant, P=0.28) than office workers and its mean values were associated (P=0.04) with working years in sewage system. Workplace air concentrations of PAHs and VOCs were elevated in sewage compared to office workplaces (P<0.01) and resulted in an increased lifetime cancer risk using toxicity equivalent factors and inhalation unit risk of cancer. In conclusion, the applied integrated and non-specific urinary biomarkers show that sewage workers experience exposure to multiple genotoxicants at the workplace. It is not possible to simply link our results with the increased cancer risk in sewage workers
Gregis, Geoffrey. "Etude et réalisation d'un système miniaturisé pour l'analyse de composés organiques volatils considérés comme des marqueurs chimiques du cancer du poumon." Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCE008/document.
Full textThe main goal of this research is to develop a miniaturized diagnostic equipment in order to identify some volatile organic compounds present in exhaled breath and referred as lung cancer biomarkers. The main scientific and technical obstacles of this project are linked to the very low concentrations of these chemical compounds and the presence of high concentrations of H2O and CO2 naturally present in exhaled breath. To address these issues, we suggest to use a SnO2-based gas sensor combined with a micro-preconcentrator and a chromatographic micro-column in order to engineer a low detection limit system. First, some specific adsorbents have been characterized with a view to concentrate chemical biomarkers trough the micro-preconcentrator. In accordance with research findings, two types of zeolites (DaY and NaY) and one type carbonaceous microspheres (W5) have been selected. Then micro-preconcentrators and chromatographic micro-columns have been developed on silicon wafers by using clean room facilities. The last step of this study was to evaluate the performances of the analytical device. After determining optimal elution and pre-concentration conditions of each VOCs, the miniaturized system achieved the analysis of an artificial breath constituted of toluene (24 ppb), 1-propanol (21 ppb) and o-xylene in presence of high concentrations of water vapors and carbon dioxide
Ghosson, Hikmat. "Development of a novel universal proxy to assess the environmental fate and impact of complex (bio)pesticides by Mass Spectrometry-based Metabolomics." Electronic Thesis or Diss., Perpignan, 2020. http://www.theses.fr/2020PERP0029.
Full textDespite the ecological and sanitary awareness, worldwide consumption of pesticides is increasing. As these chemical products represent several adverse effects on human health and environment, measures should be taken in order to limit their impacts. Biocontrol products are proposed as an alternative solution of the synthetic products. In fact, these “biopesticides” are presumed to be less harmful and relatively less persistent. However, this a priori must be examined and strict risk assessment of those new substances should be considered.The development of biocontrol solutions proceeds first of all through the proposed protocols to study their activity and their environmental fate and impact. Currently, half-life (DT50) is used in order to evaluate the environmental fate of synthetic pesticides. However, DT50 approach gives only information about pesticides' persistence in the environment, but no indications concerning the formation of degradation products or its impact on biodiversity are provided. Furthermore, biocontrol products are complex (bio)chemical mixes. The DT50 is not applicable for such complex products. Therefore, novel analytical approaches should be considered in order to overcome these difficulties.A novel approach based on meta-metabolomics and Mass Spectrometry; the “Environmental Metabolic Footprinting” (EMF), was recently introduced. It affords a novel universal and integrative proxy; the “resilience time”, dedicated to assess the environmental fate and impact of complex (bio)pesticides in environmental matrices (e.g. soil, sediment). Nonetheless, the development of such Mass Spectrometry-based untargeted meta-metabolomics approach needs to be in-depth studied. Several tasks should be addressed: 1) performant extraction protocols and GC/LC-(HR)MS-based analytical methods should be set up, 2) suitable data processing and chemometric tools should be developed to deal with the complexity of the generated datasets, 3) the impact of xenometabolome complexity on MS-based analyses should be assessed, and 4) the study of the volatile residues should be considered and thus needs new analytical methodologies to be developed.The work was carried out following 3 main axes. The first axis addressed 1) the development of extraction protocols and LC-HRMS methods to analyze both pesticides xenometabolites and soil endometabolites, and 2) the development of a novel chemometric approach to assess the extraction performance. Novel extraction protocols have been proven optimal for the EMF, and the chemometric approach was thus validated. The second axis assessed the impact of xenometabolome complexity on the determination of environmental biomarkers. Ion suppression was revealed and thus a pragmatic strategy has been developed to overcome its influence. The third axis aimed to set-up a novel methodology in order to analyze the volatile residues of complex pesticides. HS-SPME-GC-MS analyses were coupled to chemometrics in order to perform kinetics studies and to follow the transformation of the volatile residues. The chemometric workflow proved its reliability to explain pesticide’s transformation and novel xenometabolites and by-products were identified.In conclusion, significant advances were carried to the EMF. It has been consolidated for laboratory and field applications that must be investigated in order to improve the proxy and to validate it as a reliable approach for pesticides risk evaluation
Simon, Melinda Grace. "Methodological improvements for detection of volatile and non-volatile breath biomarkers." Diss., 2009. http://proquest.umi.com/pqdweb?did=1917137421&sid=1&Fmt=2&clientId=48051&RQT=309&VName=PQD.
Full text"Comprehensive Analysis of Volatile Biomarkers for Female Fertility." Master's thesis, 2018. http://hdl.handle.net/2286/R.I.49379.
Full textDissertation/Thesis
Masters Thesis Biomedical Engineering 2018
Vij, Shitiz. "Development of Chemiresistor Based Nanosensors to Detect Volatile Cancer Biomarkers." Thesis, 2019. http://hdl.handle.net/1805/18943.
Full textResearchers have shown links between various hydrocarbons and carbonyl compounds and diseases, such as cancer using exhaled breath analysis through gas chromatography/mass spectroscopy (GC/MS) analysis of volatile organic compounds (VOCs). Trained canines can detect these VOCs and can differentiate a patient suffering from cancer from a healthy control patient. In this project, an attempt has been made to develop highly sensitive sensors for the detection of low concentrations of aldehyde VOCs, such as nonanal, using conductive polymer composites (CPCs) and functionalized gold nanoparticles (f-GNPs). Facile methods have been used to enhance the sensitivity and cross-selectivity of the fabricated sensors towards nonanal. Interdigitated electrodes (IDEs) are fabricated through a photolithography process. Sensors of PEI/carbon black (CB) composite were developed via spin-coating of the material followed by the heat treatment process. Sensors of 1-Mercapto-(triethylene glycol) methyl ether functionalized GNPs are developed via drop-casting of nanomaterial and f-GNP/PEI sensors are fabricated by spin casting PEI film on top of f-GNPs. Fourier Transform Infrared (FTIR) analysis, X-Ray Diffraction (XRD) analysis, contact angle measurement, and Field Emission Scanning Electron Microscopy (FESEM) analysis was conducted to characterize the fabricated devices. The fabricated sensors have been tested with a low concentration of nonanal, nonanone, dodecane, and 1-octanol in dry air. Multiple sensors are fabricated to ensure sensors reproducibility. The sensors have been exposed repeatedly to the targeting VOC toxiv assess the repeatability of the sensors. PEI/CB sensor degradation was studied over a period of 36 days. The fabricated PEI/CB film could detect (1-80 ppm) of nonanal with higher selectivity, than the f-GNPs. The sensor0s sensitivity to nonanal was over fourteen times higher than 2-nonanone, 1-octanol, and dodecane. This shows the high selectivity of the fabricated sensor toward nonanal. In addition, the proposed sensor maintained its sensitivity to nonanal over time showing minimal degradation. The sensor response to nonanal at a relative humidity (RH) of 50% and 85% dropped less than 13% and 32% respectively. The Response of f-GNP sensors to nonanal (400 ppb - 15 ppm), dodecane (5 - 15 ppm), 1-octanol (5 - 15 ppm), and 2-nonanone (5 - 15 ppm) presented a sensitivity (∆R=R0) of 0.217%, 0.08%, 0.192% and 0.182% per ppm of the VOCs respectively. Despite the high sensitivity to the targeting VOCs, the fabricated sensors were damaged in an environment with relative humidity (RH) at 45%. A thin layer of PEI over the film was developed to ensure the sensor could tolerate longtime exposure to water vapor in an environment with RH up to 85% and enhance the sensor selectivity towards nonanal. The f-GNP/PEI sensors with nonanal (400 ppb- 15 ppm), dodecane (100 -200 ppm), 1-octanol (5 - 15 ppm) and 2-nonanone (5 - 15 ppm) presented sensitivity (∆R=R0) of 0.21%, 0.017%, 0.0438% and 0.0035% per ppm of the VOCs respectively.
2021-04-24
pei-jen, tsai, and 蔡佩真. "Exploration for the Biomarkers of Volatile Organic Compounds in Office Building." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/37190566390296711916.
Full text國立成功大學
環境醫學研究所
89
Most people spend the majority of their time in indoor environment as the modern society becomes industrialized. Consequently, the application of new building materials, and air conditioning systems has increased. In addition, the function and use of indoor environments has become even more diverse. All the above factors have, in part, contributed to the rising quantities and varieties of volatile organic compounds (VOCs) identified indoors. It is therefore important to better characterize these common indoor VOCs, and establish the analysis method of VOCs in air and blood of low concentrations. Moreover, questionnaire have been applied to determine the overall health status and prevalence of sick building syndrome (SBS) in office workers. The results suggest that SBS were frequently observed in office workers of our investigation. Most of them reported that symptoms associated with eyes, nose, or central nervous system improved when they were away from work, and office workers in business district reported greater frequency and severity than in industrial district. The most common symptom was sensory irritation in eyes, nose, or throat. This study also established the analytical method for VOCs in air and blood of low concentration using ATD-400, GC/MS and purge-and-trap concentrator, GC/FID/ECD. The R2 of standard curve of benzene, toluene, ethylbenzene, m-/p-xylene, o-xylene could be up to 0.995, and the method detection limit, accuracy and precision were in good control as well. Environmental sampling in an office building and biological monitoring for its staff was performed afterwards. The result reveals that contaminant level was low in that building and the concentration of serum VOCs were also correspondingly low. In addition, the serum VOCs appeared to be an ideal way to reflect the real outside exposure when the indoor exposure in low. The serum VOCs would therefore considered a relatively good biomarker to estimate the low level condition of outside environment.
Shih, Bo-Ren, and 施柏任. "Exposure to volatile organic compounds (VOCs) and urinary biomarkers in residents living near an industrial area." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/81943150036578044471.
Full text國立陽明大學
環境與職業衛生研究所
100
Background/objectives In recent years, there has been a sustainable increase of industrial and science parks due to the economic development of Taiwan. Volatile organic compounds (VOCs), such as benzene and toluene, are emitted during the industrial manufacturing process. When the emission of VOCs is not well-treated by various control devices, it leads to a contaminated environmental quality near the industrial park and causes adverse effects on residents. The objective of this study is two-fold: (1) to measure the urinary metabolite levels and VOCs levels via personal and environmental sampling and (2) further assess the relationships between exposure to VOCs levels and various respiratory symptoms among residents living near industrial areas. Our study will be a reference for the controlled emission of VOCs from industrial areas. Materials and methods The exposure group was selected as two elementary schools’ students and their parents living nearby industrial and science parks in Nantun District of Taichung. The control group was chosen from another site, which does not have an industrial park—in the Eastern District of Taichung. We measured each participant in the two groups, measuring repertory symptoms using a structured questionnaire, measuring VOCs levels by personal passive samplers, and measuring urinary hippuric acid (HA) and cotinine via UV and HPLC. Respiratory symptoms in schoolchildren and their parents were assessed using a questionnaire from American Thoracic Society (ATS). Results The VOC concentrations by personal sampling in the exposure group were significantly higher than those in the control group. Average levels for exposure group in students were 6.01 ppb in benzene, 21.96 ppb in toluene, and 34.74 ppb in total VOCs, significant higher than those of the control group: 2.47 ppb in benzene, 12.22 ppb in toluene, and 25.27 ppb in total VOCs. In addition, the average levels of parents in the exposure group were 7.06 ppb in benzene, 33.63 ppb in toluene, 0.7 ppb in ethylbenzene, and 50.74 ppb in total VOCs, higher than the control group parents, which were 3.21 ppb in benzene, 17.72 ppb in toluene, N.D. in ethylbenzene, and 33.14 ppb in total VOCs. The urinary hippuric acid concentrations in the exposure group were also higher. Average levels for the exposure group’s students and their parents were 642.62 and 682.04 mg/g cre. higher than 627.1 and 599.86 mg/g cre. in the control group, but there was no significant difference in the two groups. The VOCs concentrations by personal sampling were significant positive correlations with outdoor VOCs concentrations, which the exposure group in students was found correlation coefficient (r) is 0.616 in benzene, 0.413 in xylene and 0.571 in total VOCs, respectively. The personal sampling for parents in exposure group had significant moderate positive correlation with outdoor toluene concentrations (r = 0.419). The personal sampling for students in the control group was correlated with outdoor levels of benzene (r = 0.891), toluene (r = 0.615), xylene (r = 0.713), total VOCs (r = 0.734), however, only found in total VOCs concentrations (r = 0.65, p < 0.05) in the control group of parents. The significant correlations between personal sampling of VOCs and concentrations of biological monitoring were found among students and their parents. Levels of benzene, xylene and total VOCs significant positively correlated with urinary hippuric acid concentrations in the exposure group (r = 0.557, 0.433, and 0.552, respectively). It were similar trends in the control group were significant positive correlation (r = 0.713, 0.804, and 0.734, respectively). Using multiple linear regressions adjusted for covariates, of urinary HA levels for students and their parent in the exposure group were 46.755 mg/g cre. and 34.632 mg/g cre. higher than the control group, but there were no significant difference in the two groups. Using multiple logistic regression adjusted for covariates, the risk suffering from cough and children and their parent in the exposure group were 1.57 and 1.25 times higher than in the control group, but there were no significant difference in the two groups. Conclusion Residents living near Taichung industrial park were found high VOCs levels in indoor and outdoor air, and personal exposure to VOCs concentrations explained by the emission from various sources of industries. In addition, people exposed to long-term VOCs from emitting from industrial or science park causes high risk of respiratory symptoms among schoolchildren and residents. Therefore, the environmental authorities should continually reduce emissions of VOCs and other pollutants sources in industrial and science parks, and to establish the isolation zone between communities and industrial parks in order to reduce adverse effects among residents living near industrial area.
Traguedo, Ana Patrícia Imaginário. "Theoretical and experimental approaches towards the non-invasive and selective detection of microbial pathogens." Master's thesis, 2016. http://hdl.handle.net/10362/101006.
Full textMcNeal, Karen Sue. "Understanding complex Earth systems: volatile metabolites as microbial ecosystem proxies and student conceptual model development of coastal eutrophication." 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1321.
Full textChingChen and 陳婧. "Black carbon biomarker and degradation:insight from semi-volatile." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/g2dnn7.
Full text國立成功大學
地球科學系
107
Black carbon plays an important role in the global carbon cycle. Black carbon is composed of a variety of mostly incompletely-combusted products from biomass or fossil fuel. Normally considered chemically recalcitrant, black carbon may be stabilized within the natural environments for a long time, through interfacial chemical complexation of surface functional groups and minerals, and subsequent physical protection. This study is to investigate the molecular characteristics and the long-term fate of black carbon through degradation in natural environment and lab-mimicking condition. Using synchrotron-based X-ray near-edge absorption spectroscopy and high resolution time-of flight (TOF) mass spectrometry, we study the chemical structure and properties of semi-volatile compounds from black carbon made at different temperatures and from different biomass sources. We aim to seek a biomarker for the ill-defined black carbon, and probe the chemistry and functionality of small degradation products in the form of semi-volatile compounds over time. A lower level of oxidation and lower proportion was found for the semi-volatile compounds from black carbon made at higher-temperature (700C). For black carbon samples made at high temperature (700C) and buried in soil for six years, signal of biological degradation was observed. Anaerobic degradation happened to black carbon made at both low (500C) and high temperatures (700C) within the bioreactor. Chemical complexation and mineral coating was observed on the interface of black carbon and short-range-order minerals. A biomarker was found in all black carbon samples as V-type lignin component (MW166&168, C9H10O3&C8H8O4). The degradation products and path of black carbon are suggested similar to lignin. Our research provided insight on the molecular characteristics and degradation of black carbon, and contribute to the understanding of its long term fate, stabilization and functionality in the natural environment.
Pospíšilová, Veronika. "Identifikace a kvantifikace biomarkerů chorob zažívacího traktu pomocí hmotnostní spektrometrie." Master's thesis, 2014. http://www.nusl.cz/ntk/nusl-331989.
Full textAndrade, Beatriz Sousa de. "Analysis of skin volatiles using a PDMS membrane and HS-SPME/GC-MS methodology to unveil putative biomarkers for neurodegenerative diseases." Master's thesis, 2021. http://hdl.handle.net/10400.13/3147.
Full textNeurodegenerative diseases (NDDs) are a heterogeneous group of disorders characterized by progressive degeneration of structure and function of the central or peripheral nervous system. Among NDDs, Alzheimer's and Parkinson's diseases are the most prevalent and their incidence is increasing concomitantly with average life expectancy. While there aren’t yet reliable biomarkers (BMs) for most NDDs, their diagnosis relies essentially on the clinical symptoms. However, neurodegeneration begins long before the patient experiences any symptoms. Therefore, there is an obvious interest in the early diagnosis of NDDs. This would allow the anticipation of the treatment and mitigation of the negative effects of neurodegeneration. The characterization of volatile organic metabolites (VOMs) composition of human biofluids is being explored as a promising and non-invasive tool to unveil BMs for the diagnosis of human diseases and infections. The VOMs profiles can provide important metabolic information, particularly about metabolic changes caused by different clinical conditions, including NDDs. In this context, the aim of this work was to develop a technique using polidimetilsiloxane (PDMS) membranes and a method of headspace solid phase microextraction (HS-SPME) followed by gas chromatography coupled to mass spectrometry (GC-MS) analysis to discover possible BMs for NDDs. The developed method allowed us to identify 82 VOMs – 67 in the arm, 68 in the ear and 69 in the nape of control subjects. However, it would be necessary to analyse a larger group of subjectsto improve the technique and obtain more robust data before introducing the NDDs patients sampling. This work suggests that the analysis of volatomic profiles of the skin can be an important approach to identify potential volatile BMs for NDDs. Ultimately, this can be a seamless tool for the identification of putative volatile BMs of different NDDs with a great potential to integrate in point-of-care testing (POCT) devices for the clinical environment.
Marchand, Axelle. "Évaluation et modélisation de l’impact de la coexposition de composés organiques volatils sur l’excrétion de leurs biomarqueurs urinaires." Thèse, 2014. http://hdl.handle.net/1866/12109.
Full textEvaluation of volatile organic compounds (VOC) exposure commonly resorts to urinary metabolite analyses, assuming that no interaction occur between coexposed chemicals. However, previous studies have reported competitive inhibition between toluene (TOL), ethylbenzene (EBZ) and m-xylene (XYL). Chloroform, which is also metabolized by CYP2E1, is also often found in human biomonitoring samples along with the mentioned VOCs. The goal of the present study was to evaluate if chloroform (CHL) can interact with previous VOC and to evaluate those interactions at the urinary biomarker excretion level for corresponding metabolites, namely o-cresol, mandelic acid and m-methylhippuric acid for TOL, EBZ and XYL respectively. To obtain human data, five male volunteers were exposed by inhalation to different VOC combinations (single and binary or quaternary mixtures) where concentration of each chemical was equal to 1/4 or 1/8 of the threshold limit value (TLV) for 6h. Exhaled air blood and urine samples were collected. These data were then compared with existing physiologically based pharmacokinetic (PBPK) model predictions for adjustment for urinary excretion. Some differences were observed between single and mixed exposures but they may be mainly related to volunteer replacements throughout experiments. Vmax values for EBZ and CHL were optimized to better fit blood data. Except for EBZ model, all urinary excretion parameters were taken from the literature. Models adapted in the present study adequately simulated experimental data.