| 1. |
- Rahman, Aminur, 1984-
(author)
-
Bioremediation of Toxic Metals for Protecting Human Health and the Ecosystem
- 2016
-
Doctoral thesis (other academic/artistic)abstract
- Heavy metal pollutants, discharged into the ecosystem as waste by anthropogenic activities, contaminate drinking water for millions of people and animals in many regions of the world. Long term exposure to these metals, leads to several lethal diseases like cancer, keratosis, gangrene, diabetes, cardio- vascular disorders, etc. Therefore, removal of these pollutants from soil, water and environment is of great importance for human welfare. One of the possible eco-friendly solutions to this problem is the use of microorganisms that can accumulate the heavy metals from the contaminated sources, hence reducing the pollutant contents to a safe level.In this thesis an arsenic resistant bacterium Lysinibacillus sphaericus B1-CDA, a chromium resistant bacterium Enterobacter cloacae B2-DHA and a nickel resistant bacterium Lysinibacillus sp. BA2 were isolated and studied. The minimum inhibitory concentration values of these isolates are 500 mM sodium arsenate, 5.5 mM potassium chromate and 9 mM nickel chloride, respectively. The time of flight-secondary ion mass spectrometry and inductively coupled plasma-mass spectroscopy analyses revealed that after 120 h of exposure, the intracellular accumulation of arsenic in B1-CDA and chromium in B2-DHA were 5.0 mg/g dwt and 320 μg/g dwt of cell biomass, respectively. However, the arsenic and chromium contents in the liquid medium were reduced to 50% and 81%, respectively. The adsorption values of BA2 when exposed to nickel for 6 h were 238.04 mg of Ni(II) per gram of dead biomass indicating BA2 can reduce nickel content in the solution to 53.89%. Scanning electron micrograph depicted the effect of these metals on cellular morphology of the isolates. The genetic composition of B1-CDA and B2-DHA were studied in detail by sequencing of whole genomes. All genes of B1-CDA and B2-DHA predicted to be associated with resistance to heavy metals were annotated.The findings in this study accentuate the significance of these bacteria in removing toxic metals from the contaminated sources. The genetic mechanisms of these isolates in absorbing and thus removing toxic metals could be used as vehicles to cope with metal toxicity of the contaminated effluents discharged to the nature by industries and other human activities.
|
|
| 2. |
- Carlsson, Jessica, 1984-
(author)
-
Identification of miRNA expression profiles for diagnosis and prognosis of prostate cancer
- 2012
-
Doctoral thesis (other academic/artistic)abstract
- Cancer of the prostate (CaP) is the most common malignancy diagnosed in men in the Western society. During the last years, prostate specific antigen (PSA) has been used as a biomarker for CaP, although a high PSA value is not specific for CaP. Thus, there is an urgent need for new and improved diagnostic markers for CaP.In this thesis, the aim was to find a miRNA signature for diagnosis of CaP and to elucidate if differences in behavior between transition zone and peripheral zone tumors are reflected in miRNA expression. One of the major findings is anexpression signature based on nine miRNAs that with high accuracy (85%) could classify normal and malignant tissues from the transition zone of the prostate. The results furthermore show that the major differences in miRNA expression are found between normal and malignant tissues, rather than between the different zones. In addition, tumors arising in the peripheral zone have fewer changes in miRNA expression compared to tumors in the transition zone, indicating that the peripheral zone is more prone to tumor development compared to the transition zone of the prostate.A crucial step in pre-processing of expression data, in order to differentiate true biological changes, is the normalization step. Therefore, an additional aim of this thesis was to compare different normalization methods for qPCR array data in miRNA expression experiments. The results show that data-driven methods based on quantile normalization performs the best. The results also show that in smaller miRNA expression studies, only investigating a few miRNAs, RNU24 is the most suitable endogenous control gene for normalization.Taken together, the results in this thesis show the importance of miRNAs and the possibility of their future use as biomarkers in the field of prostate cancer.
|
|
| 3. |
- Trenta, Cristina, Associate professor, docent, 1967-
(author)
-
VAT in peer-to-peer content distribution : towards a tax proposal for decentralized networks
- 2013
-
Doctoral thesis (other academic/artistic)abstract
- Peer-to-peer (P2P) is just the most prominent among a number of new technologies and social phenomena which allow easy searching, downloading, and sharing of resources online.P2P networks are increasingly becoming an important medium for the exchange of digital information, in both legitimate and illegitimate scenarios. New business models are prefigured, pioneered, and fostered by early adopters and innovative companies, but the disruptive, personal, many-to-many model P2P enables has largely framed it also as a threat to the media and content industries as a whole. All digital or digitizable media products, software, films and music in particular, whose distribution models have been overlaid by the new, different and largely unorthodox technologically-driven social dynamics of large-scale sharing face an unprecedented challenge, an interesting opportunity, and the risk of legal double-standards. Taxation is a particularly critical element, with vast repercussions on the development of a mature, profitable market.But do P2P transactions fall within the field of consumption taxation? Should they? Will they in the foreseeable future? What benefits businesses enterprises, the international community, the EU and national tax authorities might achieve by considering them fully integrated with the different VAT systems? What fiscal, and hence economic, consequences might result from classifying a file-sharing operation as liable of consumption taxation for all players involved? Would this create a new market and foster economic growth?The status quo for digital and media supplies using P2P technologies will be analyzed in detail within the framing of an interdisciplinary approach. Challenges and opportunities will be assessed through the lenses of consumption taxation and copyright law, and measured against the two foundational powers of a state, the power to apply taxation and the power to punish unlawful action.P2P networks and technologies are going to play a critical role in the distribution of digital content. Whether as a convenient, alternative, economically-sound channel to distribute content through, or as a legal wasteland, remains to be seen. Hopefully, this book will help the conversation along
|
|
