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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

Molecular regulation of universal stress proteins in environmentally mediated schistosomiasis parasites

Mbah, Andreas Nji 24 April 2014 (has links)
Human schistosomiasis popularly known as bilharzias in many regions of Africa is a freshwater snail-transmitted disease caused by parasitic flatworms known as schistosomes. The growth and development of schistosomes typically requires developmental stages in multiple hosts and transmission stages in freshwater. These life cycle environments present a plethora of stressors. Certain gene families including heat shock proteins (HSPs/Hsps) and universal stress proteins (USPs) help schistosomes to respond to unfavourable conditions. The availability of genomes sequences information for Schistosoma japonicum, Schistosoma mansoni and Schistosoma haematobium provide unique research resources to apply bioinformatics analysis of its associated USPs to predict regulatory features from sequence analysis. The objectives of the research were to (i) Infer the biochemical and environmental regulation of universal stress proteins of Schistosoma species; (ii) Identify biological function relevant protein sequence and structure features for prioritized universal stress proteins from Schistosoma species; (iii) Determine the distinctive structural features of a predicted regulator of Schistosoma adenylate cyclase activity that has possible influence on the functioning of universal stress proteins. The findings revealed that (i) schistosomes USPs are hydrophilic and very reactive in the water environment or in aqueous phase, which seems adaptive with their immediate environment and developmental stages; (ii) The functions of Smp_076400 and Sjp_0058490 (Q86DW2) are regulated by conserved binding site residues and metallic ions ligands (Ca2+, Mg2+ and Zn2+), particularly Ca2+ predicted to bind to both USPs; (iii) The S. mansoni life cycle and stress resistance pathway protein (Smp_059340.1) is regulated by Ser53, Thr188, Gly210 and Asp207 residues. The overall scope has highlighted the role of bioinformatics in predicting exploitable regulatory features of schistosome universal stress proteins and biological pathways that might lead to identification of putative functional biomarkers of common environmental diseases. The findings of this research can be applicable to other areas of environmental health and environmental genomics. / Environmental Sciences / (D. Litt et Phil. (Environmental Sciences)
12

Complex Models of Genetic and Environmental Influences on Human Cognition. Implications for Functional Psychoses / Modelos complejos de las influencias genéticas y ambientales en la cognición humana. Implicaciones para las psicosis funcionales

Goldberg, Ximena 18 June 2012 (has links)
The general construct of human cognition implies a series of mental processes by means of which human interpret and consequently act on the world that surrounds them (Sternberg y Mio, 2009). During the last decades, the recognition of human diversity and psychological variability among individuals has encouraged challenging questions addressing inter-individual differences that make each subject unique in terms of their cognitive performance (Baddeley, 2003; Botvinick, 2008). In particular, quantitative genetic studies show that both genetic variability and environmental factors are involved in the phenotypic expression of cognitive functions (Plomin, 2011). However, the mechanisms by which genes and exposure to environmental influences may contribute to the observed variability are not yet clear. The study of the origins of inter-individual differences in cognition is strongly associated with the ontogenic development of the human brain (Tau, 2010). As a consequence, cognitive alterations are considered a central trait in those mental disorders where neurodevelopmental alterations are assumed to exist, such as schizophrenia. This disease, which affects around 1% of the world’s population, is one of the main causes of years lost due to disability (WHO, 2004), while cognitive alterations in these patients explain about 20%-60% of the variance in measures of outcome (Green, 2004). The aetiological model of neurodevelopment in schizophrenia proposes that this disease might be the expression of neurobiological compromise that could begin early in the lifespan, even before the onset of the clinical symptoms (van Os, 2009). However, and despite the scientific efforts invested in the elucidation of its aetiological underpinnings, the heterogeneous presentation of the disease has prevented a deeper comprehension of these mechanisms. Are all cognitive domains heritable? Are there long-term consequences on cognition for the early exposure to environmental impact? What is the association between genetic variability and cognitive vulnerability? Can we identify specific neurobiological pathways in the expression of the cognitive alterations of patients with schizophrenia? These questions are explored in the present thesis through the analyses of twins- and family-based samples, which constitute powerful designs to study the effects of genetic and environmental variability on human cognition. In the six chapters of results that are the body of this thesis, complex models are proposed that aim at representing the mechanisms involved in the origin of cognitive variability at the population level. The findings included indicate that this variability could be the result of the relative contribution of genetic determination and environmental modelling, which could vary in different cognitive functions following ontogenic mechanisms of neurodevelopment. Specifically, results are reported on the influences of childhood maltreatment and socioeconomic status as environmental stressors, as well as Val158Met functional polymorphism of COMT gene as a genetic factor. The aetiological implications of the study of these processes are extended to the field of mental disorders, as the results may indicate that the cognitive variability present among patients with schizophrenia could support a model of developmental compromise in this disease. Accordingly, the effects of genetic and environmental influences on behaviour may underlie the heterogeneous expression of this highly disabling mental disorder. To sum up, the phenotypic diversity of schizophrenia and human cognition, far from representing an obstacle, lays the foundations for complex models of these traits that may feed an increasing understanding of their aetiology (Belsky, 2011). These findings highlight the putative role of neurobiological liability traits in crucial aspects of clinical practice. Risk factors might be identified that could be included as potential guidelines in the assessment and management of need-adapted treatments (Leiftker, 2009). Moreover, liability traits might operate as markers in preventive interventions for targeting individuals at risk of developing particular forms of the disease (Keshavan, 2011). / El constructo general de cognición humana involucra una serie de procesos mentales por medio de los cuales los individuos perciben, interpretan y, en consecuencia, actúan sobre la realidad que los rodea y sobre sus pares (Sternberg y Mio, 2009). En los últimos años, el reconocimiento de la diversidad humana y la variabilidad de los rasgos psicológicos entre los individuos ha promovido preguntas acerca de las diferencias inter-individuales que hacen a cada sujeto único en términos de cognición (Baddeley, 2003; Botvinick, 2008). En particular, los estudios de genética cuantitativa demuestran que tanto la variabilidad genética como los factores ambientales podrían estar involucrados en la expresión fenotípica de las funciones cognitivas (Plomin, 2011). Sin embargo, aún no son claros los mecanismos específicos por medio de los cuales los genes y el ambiente contribuyen a esta variabilidad. Las alteraciones cognitivas son un rasgo central en enfermedades mentales donde se presume que existen alteraciones del neurodesarrollo, como lo es la esquizofrenia. El modelo etiológico del neurodesarrollo de la esquizofrenia propone que esta enfermedad se expresaría como consecuencia de alteraciones neurobiológicas que iniciarían en una época temprana de la vida, incluso antes del desencadenamiento de los síntomas clínicos (van Os, 2009). No obstante, la presentación heterogénea de la enfermedad ha dificultado una comprensión más clara de los mecanismos involucrados en su manifestación. ¿Son todas las funciones cognitivas igualmente heredables? ¿Tienen los factores ambientales tempranos consecuencias a largo plazo sobre la cognición? ¿Cuál es la relación entre variabilidad genética y vulnerabilidad cognitiva? ¿Existen vías neurobiológicas específicas para la manifestación de las alteraciones cognitivas en pacientes con esquizofrenia? Estas preguntas se exploran en la presente tesis a partir de análisis basados en muestras de gemelos y en grupos familiares, que constituyen una manera metodológicamente potente de estudiar los efectos de la variabilidad genética y ambiental sobre la cognición humana. En este sentido, la diversidad fenotípica de la esquizofrenia y la cognición humana, lejos de representar un obstáculo para la investigación de su etiología, sienta las bases de modelos complejos que podrían fomentar una comprensión cada vez más completa de los mecanismos de vulnerabilidad y resiliencia posiblemente involucrados en su origen (Belsky, 2011).
13

Oxidative stress induced by different stressors and its impact on resistance of spring barley (Hordeum vulgare L.) / Skirtingų veiksnių sukeliamas oksidacinis stresas ir jo įtaka vasarinių miežių (Hordeum vulgare L.) atsparumui

Kacienė, Giedrė 23 May 2014 (has links)
Oxidative stress, described as an imbalance between the concentration of reactive oxygen species (ROS) and antioxidants, is one of the most important mechanisms of stressors’ action on plants. On the other hand, similar plants’ response to different stress factors and oxidative stress induced increase in the activity of antioxidative enzymes triggers plants’ adaptation to the particular stressor, as well as cross-adaptation to different stress factors. The aim of the dissertation research is to investigate the impact of different stress factors (ozone, UV-B radiation, drought and heavy metals) on growth and intensity of oxidative stress of spring barley, and to estimate the role of oxidative stress and antioxidative system on plants resistance and cross-adaptation to different stress factors. It was detected, that oxidative stress is the major cause of plant’s growth reduction induced by similar stress factors (heavy metals), whereas the specific impact of stressors is low. When plants are exposed to different stressors (drought, ozone, UV-B radiation, heavy metals Cd and Cu), the impact of their specific action increases, however, oxidative stress remains the major reason of plants’ growth reduction. The increase in antioxidative protection and the reduction in the intensity of oxidative stress is the reason of plant adaptation to the stressors with strong oxidative features (Cu and ozone); whereas cross-adaptation to the stressors with lower oxidative potential (Cd and UV-B... [to full text] / Vienas iš pagrindinių daugumos stresorių neigiamo poveikio augalams mechanizmų yra oksidacinis stresas – disbalansas tarp aktyvių deguonies junginių (ADJ) ir antioksidantų koncentracijos bei aktyvumo pokyčių ląstelėje. Kita vertus, panaši augalų reakcija į skirtingų veiksnių poveikį bei oksidacinio streso sužadintas antioksidacinių fermentų aktyvumo padidėjimas gali lemti augalų prisitaikymą ir padidėjusį jų atsparumą ne tik tam pačiam, bet ir kitiems nepalankiems veiksniams, t. y. kryžminę adaptaciją. Disertacijos tyrimų tikslas – ištirti skirtingų savo prigimtimi streso veiksnių (ozono, UV-B spinduliuotės, sausros ir sunkiųjų metalų) poveikį vasarinių miežių augimui ir oksidacinio streso stiprumui ir įvertinti oksidacinio streso bei antioksidacinės sistemos įtaką augalų atsparumui skirtingų stresorių poveikiui ir kryžminės adaptacijos formavimuisi. Nustatyta, kad skirtingų tos pačios grupės veiksnių (sunkiųjų metalų) sukeltas oksidacinis stresas labiausiai lemia miežių augimo depresiją, o savitasis atskirų veiksnių poveikis yra nežymus. Veikiant skirtingos prigimties aplinkos veiksniams (sausrai, ozonui, UV-B spinduliuotei, sunkiesiems metalams) savitojo jų poveikio įtaka miežių augimui sustiprėja, tačiau oksidacinio streso poveikis vis tiek lieka stipriausias. Antioksidacinės sistemos aktyvumo padidėjimas ir oksidacinio streso susilpnėjimas lemia miežių kryžminę adaptaciją stipriomis oksidacinėmis savybėmis pasižyminčių aplinkos veiksnių poveikiui (variui ir ozonui), o... [toliau žr. visą tekstą]
14

Skirtingų veiksnių sukeliamas oksidacinis stresas ir jo įtaka vasarinių miežių (Hordeum vulgare L.) atsparumui / Oxidative stress induced by different stressors and its impact on resistance of spring barley (Hordeum vulgare L.)

Kacienė, Giedrė 23 May 2014 (has links)
Vienas iš pagrindinių daugumos stresorių neigiamo poveikio augalams mechanizmų yra oksidacinis stresas – disbalansas tarp aktyvių deguonies junginių (ADJ) ir antioksidantų koncentracijos bei aktyvumo pokyčių ląstelėje. Kita vertus, panaši augalų reakcija į skirtingų veiksnių poveikį bei oksidacinio streso sužadintas antioksidacinių fermentų aktyvumo padidėjimas gali lemti augalų prisitaikymą ir padidėjusį jų atsparumą ne tik tam pačiam, bet ir kitiems nepalankiems veiksniams, t. y. kryžminę adaptaciją. Disertacijos tyrimų tikslas – ištirti skirtingų savo prigimtimi streso veiksnių (ozono, UV-B spinduliuotės, sausros ir sunkiųjų metalų) poveikį vasarinių miežių augimui ir oksidacinio streso stiprumui ir įvertinti oksidacinio streso bei antioksidacinės sistemos įtaką augalų atsparumui skirtingų stresorių poveikiui ir kryžminės adaptacijos formavimuisi. Nustatyta, kad skirtingų tos pačios grupės veiksnių (sunkiųjų metalų) sukeltas oksidacinis stresas labiausiai lemia miežių augimo depresiją, o savitasis atskirų veiksnių poveikis yra nežymus. Veikiant skirtingos prigimties aplinkos veiksniams (sausrai, ozonui, UV-B spinduliuotei, sunkiesiems metalams) savitojo jų poveikio įtaka miežių augimui sustiprėja, tačiau oksidacinio streso poveikis vis tiek lieka stipriausias. Antioksidacinės sistemos aktyvumo padidėjimas ir oksidacinio streso susilpnėjimas lemia miežių kryžminę adaptaciją stipriomis oksidacinėmis savybėmis pasižyminčių aplinkos veiksnių poveikiui (variui ir ozonui), o... [toliau žr. visą tekstą] / Oxidative stress, described as an imbalance between the concentration of reactive oxygen species (ROS) and antioxidants, is one of the most important mechanisms of stressors’ action on plants. On the other hand, similar plants’ response to different stress factors and oxidative stress induced increase in the activity of antioxidative enzymes triggers plants’ adaptation to the particular stressor, as well as cross-adaptation to different stress factors. The aim of the dissertation research is to investigate the impact of different stress factors (ozone, UV-B radiation, drought and heavy metals) on growth and intensity of oxidative stress of spring barley, and to estimate the role of oxidative stress and antioxidative system on plants resistance and cross-adaptation to different stress factors. It was detected, that oxidative stress is the major cause of plant’s growth reduction induced by similar stress factors (heavy metals), whereas the specific impact of stressors is low. When plants are exposed to different stressors (drought, ozone, UV-B radiation, heavy metals Cd and Cu), the impact of their specific action increases, however, oxidative stress remains the major reason of plants’ growth reduction. The increase in antioxidative protection and the reduction in the intensity of oxidative stress is the reason of plant adaptation to the stressors with strong oxidative features (Cu and ozone); whereas cross-adaptation to the stressors with lower oxidative potential (Cd and UV-B... [to full text]
15

Molecular regulation of universal stress proteins in environmentally mediated schistosomiasis parasites

Mbah, Andreas Nji 24 April 2014 (has links)
Human schistosomiasis popularly known as bilharzias in many regions of Africa is a freshwater snail-transmitted disease caused by parasitic flatworms known as schistosomes. The growth and development of schistosomes typically requires developmental stages in multiple hosts and transmission stages in freshwater. These life cycle environments present a plethora of stressors. Certain gene families including heat shock proteins (HSPs/Hsps) and universal stress proteins (USPs) help schistosomes to respond to unfavourable conditions. The availability of genomes sequences information for Schistosoma japonicum, Schistosoma mansoni and Schistosoma haematobium provide unique research resources to apply bioinformatics analysis of its associated USPs to predict regulatory features from sequence analysis. The objectives of the research were to (i) Infer the biochemical and environmental regulation of universal stress proteins of Schistosoma species; (ii) Identify biological function relevant protein sequence and structure features for prioritized universal stress proteins from Schistosoma species; (iii) Determine the distinctive structural features of a predicted regulator of Schistosoma adenylate cyclase activity that has possible influence on the functioning of universal stress proteins. The findings revealed that (i) schistosomes USPs are hydrophilic and very reactive in the water environment or in aqueous phase, which seems adaptive with their immediate environment and developmental stages; (ii) The functions of Smp_076400 and Sjp_0058490 (Q86DW2) are regulated by conserved binding site residues and metallic ions ligands (Ca2+, Mg2+ and Zn2+), particularly Ca2+ predicted to bind to both USPs; (iii) The S. mansoni life cycle and stress resistance pathway protein (Smp_059340.1) is regulated by Ser53, Thr188, Gly210 and Asp207 residues. The overall scope has highlighted the role of bioinformatics in predicting exploitable regulatory features of schistosome universal stress proteins and biological pathways that might lead to identification of putative functional biomarkers of common environmental diseases. The findings of this research can be applicable to other areas of environmental health and environmental genomics. / Environmental Sciences / (D. Litt et Phil. (Environmental Sciences)
16

Healthy and pleasant commuting in cities / Exploring cyclists’ and pedestrians’ personal exposure, wellbeing and protective practices on-the-move

Marquart, Heike 08 June 2023 (has links)
In dieser Doktorarbeit wurde untersucht, welche Faktoren Wohlbefinden, wahrgenommene Gesundheit und Mobilitätspraktiken von Radfahrenden und Fußgänger:innen während des Unterwegsseins beeinflussen. Ziel war es, die persönliche Exposition gegenüber Feinstaub und Lärm unterwegs zu messen und diese der individuell wahrgenommenen Belastung gegenüberzustellen. Zudem wurden weitere Faktoren, die das Wohlbefinden beeinflussen, untersucht. Die Arbeit beleuchtet überdies, wie über gesunde und angenehme Mobilität informiert werden könnte. Zuerst wurden mobile qualitative Interviews (Go-/Ride-Alongs) durchgeführt und mit tragbaren Sensoren zur Messung von Feinstaub und Lärm ergänzt. Der situative Kontext, die sensorische Wahrnehmung und soziale Aspekte beeinflussen, ob das Unterwegsseins in der Stadt als gesund und angenehm empfunden wird. Diese Faktoren können in vergleichsweise als hoch belastend gemessenen Situationen ausgleichend wirken. Weiterhin wurden Informationsmöglichkeiten für eine gesunde Mobilität in der Stadt exploriert. Ein Literaturreview hat aufgezeigt, dass Gesundheitsthemen wenig Berücksichtigung in Forschung zu Mobilitäts-Apps finden. Daran anschließend wurden Fokusgruppen durchgeführt. Es wurde ermittelt, wie gesunde und angenehme Routen kommuniziert werden können. Hier könnendas Vorhandensein von Routenalternativen und Bewältigungsstrategien ein Gefühl von Selbstwirksamkeit geben. Es wurde eine „pleasant routing app“ vorgeschlagen, die angenehme und gesunde Routenaspekte integriert. Um die Attraktivität des Fahrradfahrens und zu Fuß Gehens zu steigern, sollten Erfahrungen, Wahrnehmungen und Praktiken von Radfahrenden und Fußgänger:innen berücksichtigt werden. Letztendlich kann somit aktive Mobilität ihr Potenzial entfalten und zu einer lebenswerten, gesunden und umweltfreundlichen Stadt beitragen. / This thesis investigates factors influencing cyclists’ and pedestrians’ health and wellbeing on-the-move. Moreover, the possibilities of smartphone apps for supporting a healthy and pleasant trip are investigated. The scope of this thesis is to combine the topic healthy and pleasant mobility with possibilities of mobility apps. First, the thesis explores how cyclists and pedestrians perceive their personal exposure towards air pollution and noise as well as other factors influencing commuting experience and wellbeing on-the-move. This is contrasted to actual measured particulate matter and noise. Qualitative interviews on-the-move (‘go-/ride-alongs’) are complemented by wearable sensors measuring particulate matter and noise. The results show discrepancies as well as coherences between perceived and measured exposure. The situational context, sensory awareness (e.g. water views) and social cues (e.g. seeing other people) are important for a perceived pleasant commute, even in polluted areas. Second, this thesis identifies how far health impacting factors are considered in research using mobility apps to identify their possibilities for supporting a healthy commute. A literature review reveals that research applying mobility apps is lacking the consideration of health topics and it is proposed to integrate health topics in mobility app development. Following these findings, the thesis investigates communication options to inform about a healthy and pleasant commute. Focus groups were applied showing that information should include feasible coping strategies and increase self-efficacy. Pleasant trip characteristics could be included in a healthy mobility app. If active mode users’ experiences, perceptions and practices are considered, cycling and walking can become more attractive and more people are encouraged to cycle or walk. Hence, active modes can unfold their potential for supporting the transformation towards liveable, healthy and environmentally friendly cities.
17

Analysis of environmental stressors on ecosystems of Xuan Thuy National Park, Vietnam: Research paper

Haneji, Choshin, Amemiya, Takashi, Itoh, Kiminori, Mochida, Yukira, Hoang, Thi Thanh Nhan, Pham, Van Cu 19 August 2015 (has links)
Above-ground biomass was allometrically estimated to quantify the amount of mangrove species in selected quadrats of Xuan Thuy National Park. Physicochemical properties of surrounding waters and soils were measured and treated stochastically by correlational analysis with estimated biomass values. Correlation results suggested that qualities of surrounding waters and soils are not the principal inhibitors of mangrove growth in Xuan Thuy. The available historical records infer that the main factor of mangrove loss in the past lay on land reclamation for shrimp aquaculture. In addition, results of correlation analysis showed geographical coincidence of mangrove fragmentation with influence area of water channeling used for aquaculture activities. Furthermore, the distribution of anomalous values of metals concentration was corresponding with anthropological activities associated to clam aquaculture and sand extraction. Based on the aforementioned analysis and the information on anthropological activities in the buffer zone of Xuan Thuy, were provided basic information on inherent environmental stressors of ecosystems in Xuan Thuy National Park. / Sinh khối trên mặt đất đã được ước tính theo phương pháp tương quan sinh trưởng để đưa ra số lượng các loài đước trong các mẫu vuông được lựa chọn tại Vườn quốc gia Xuân Thủy. Các đặc tính hóa-lí của những vùng nước và đất xung quanh đã được đo đạc và xử lí ngẫu nhiên bằng cách phân tích tương quan với những giá trị sinh khối ước tính. Kết quả tương quan cho thấy rằng chất lượng nước và đất xung quanh không phải là những thước đo chính cho tốc độ phát triển cây đước ở Xuân Thủy. Những ghi chép cũ đã kết luận rằng việc sử dụng đất để nuôi tôm là tác nhân chính dẫn tới suy giảm loài đước trong quá khứ. Bên cạnh đó, kết quả phân tích tương quan cho thấy sựtrùng hợp về mặt địa lý giữa sự phân mảnh của loài đước và những vùng nước bị ảnh hưởng do việc nuôi trồng thủy sản. Hơn nữa, sự phân bố bất thường của các giá trị đo mức độ tập trung kim loại cũng tương ứng với các hoạt động nuôi trồng thủy sản và khai thác cát của con người. Những phân tích nêu trên và nghiên cứu về hoạt động của con người tại vùng đệm của Xuân Thủy sẽ cung cấp những thông tin cơ bản về những mối đe dọa môi trường hệ sinh thái tại Vườn Quốc Gia Xuân Thủy.
18

Short-Time Temporal Changes of CH4 Fluxes in Different Tropical Tree Species : In-situ research regarding methane emissions from inundation-adapted Amazonian tree species in Jardim Botânico do Rio de Janeiro.

Athley, Emelie January 2023 (has links)
Methane (CH4) is guaranteed to affect climate change and is essential in rising temperatures. Scientists have known for over two decades that wetlands emit CH4 to such an extent that it affects our climate. Tropical trees that grow in wetlands tend to emit or act as a conduit of CH4, to the extent that it has a negative environmental impact. However, until this study, no one has examined whether wetland species growing in another environment have the same effects. Hence, this thesis aimed to collect data from wetland-adapted tropical trees in a non-wetland environment, namely the Botanical Garden in Rio de Janeiro. The results showed a difference in the sampling height of the stem, namely that a decrease in emission is seen with an increased height. All the species except one (Pseudobombax munguba) showed both assimilation and emission from the day-to-day measurements of CH4, which speaks for the trees acting both as a sink and a source of CH4. This suggests that the species are more robust than the environmental stressors in a non-wetland environment. Previous studies have found that increased CH4 emissions can be seen with different meteorological parameters. The results presented in this thesis show the opposite, that some species tend to emit less or assimilate more CH4 during days with increased rainfall, humidity, and temperature.

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