| 1. |
- Lynch, S.A., et al.
(författare)
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Toward silicon-based lasers for terahertz sources
- 2006
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - 1077-260X .- 1558-4542. ; 12:6, s. 1570-1577
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Tidskriftsartikel (refereegranskat)abstract
- Producing an electrically pumped silicon-based laser at terahertz frequencies is gaining increased attention these days. This paper reviews the recent advances in the search for a silicon-based terahertz laser. Topics covered include resonant tunneling in p-type Si/SiGe, terahertz intersubband electroluminescence from quantum cascade structures, intersubband lifetime measurements in Si/SiGe quantum wells, enhanced optical guiding using buried suicide layers, and the potential for exploiting common impurity dopants in silicon such as boron and phosphorus to realize a terahertz laser. © 2006 IEEE.
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| 2. |
- Dickinson, Paul A, et al.
(författare)
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Clinical relevance of dissolution testing in quality by design
- 2008
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Ingår i: AAPS Journal. - : Springer Science and Business Media LLC. - 1550-7416. ; 10:2, s. 380-390
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Forskningsöversikt (refereegranskat)abstract
- Quality by design (QbD) has recently been introduced in pharmaceutical product development in a regulatory context and the process of implementing such concepts in the drug approval process is presently on-going. This has the potential to allow for a more flexible regulatory approach based on understanding and optimisation of how design of a product and its manufacturing process may affect product quality. Thus, adding restrictions to manufacturing beyond what can be motivated by clinical quality brings no benefits but only additional costs. This leads to a challenge for biopharmaceutical scientists to link clinical product performance to critical manufacturing attributes. In vitro dissolution testing is clearly a key tool for this purpose and the present bioequivalence guidelines and biopharmaceutical classification system (BCS) provides a platform for regulatory applications of in vitro dissolution as a marker for consistency in clinical outcomes. However, the application of these concepts might need to be further developed in the context of QbD to take advantage of the higher level of understanding that is implied and displayed in regulatory documentation utilising QbD concepts. Aspects that should be considered include identification of rate limiting steps in the absorption process that can be linked to pharmacokinetic variables and used for prediction of bioavailability variables, in vivo relevance of in vitro dissolution test conditions and performance/interpretation of specific bioavailability studies on critical formulation/process variables. This article will give some examples and suggestions how clinical relevance of dissolution testing can be achieved in the context of QbD derived from a specific case study for a BCS II compound.
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| 3. |
- Gürer, D., et al.
(författare)
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Women in Computing
- 2009
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Ingår i: Wiley Encyclopedia of Computer Science and Engineering. - Hoboken, NJ, USA : John Wiley & Sons. - 9780470050118 ; , s. 3099-3122
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Johannesson, Hanna, et al.
(författare)
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Concerted evolution in the rpeats of an immunomodulating cell surface protein, SOWgp, of the human pathogenic fungi Coccidioides immitis and C. posadasii.
- 2005
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Ingår i: Genetics.
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Tidskriftsartikel (refereegranskat)abstract
- Genome dynamics that allow pathogens to escape host immune responses are fundamental to our understanding of host-pathogen interactions. Here we present the first population-based study of the process of concerted evolution in the repetitive domain of a protein-coding gene. This gene, SOWgp, encodes the immunodominant protein in the parasitic phase of the human pathogenic fungi Coccidioides immitis and C. posadasii. We sequenced the entire gene from strains representing the geographic ranges of the two Coccidioides species. By using phylogenetic and genetic distance analyses we discovered that the repetitive part of SOWgp evolves by concerted evolution, predominantly by the mechanism of unequal crossing over. We implemented a mathematical model originally developed for multigene families to estimate the rate of homogenization and recombination of the repetitive array, and the results indicate that the pattern of concerted evolution is a result of homogenization of repeat units proceeding at a rate close to the nucleotide point mutation rate. The release of the SOWgp molecules by the pathogen during proliferation may mislead the host: we speculate that the pathogen benefits from concerted evolution of repeated domains in SOWgp by an enhanced ability to misdirect the host’s immune system.
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| 5. |
- Johannesson, Henrik, et al.
(författare)
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Phase-specific gene expression underlying morphological adaptations of the dimorphic human pathogenic fungus, Coccidioides posadasii
- 2006
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Ingår i: Fungal Genetics and Biology. - : Elsevier BV. - 1087-1845 .- 1096-0937. ; 43:8, s. 545-559
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Tidskriftsartikel (refereegranskat)abstract
- Coccidioides posadasii is a dimorphic fungal pathogen that grows as a Wlamentous saprobe in the soil and as endosporulating spheruleswithin the host. To identify genes speciWc to the pathogenic phase of Co. posadasii, we carried out a large-scale study of gene expression intwo isolates of the species. From the sequenced Co. posadasii genome, we chose 1000 open reading frames to construct a 70-mer microarray.RNA was recovered from both isolates at three life-cycle phases: hyphae, presegmented spherules, and spherules releasing endospores.Comparative hybridizations were conducted in a circuit design, permitting comparison between both isolates at all three life-cyclephases, and among all life-cycle phases for each isolate. By using this approach, we identiWed 92 genes that were diVerentially expressedbetween pathogenic and saprobic phases in both fungal isolates, and 43 genes with consistent diVerential expression between the two parasiticdevelopmental phases. Genes with elevated expression in the pathogenic phases of both isolates included a number of genes thatwere involved in the response to environmental stress as well as in the metabolism of lipids. The latter observation is in agreement withprevious studies demonstrating that spherules contain a higher proportion of lipids than saprobic phase tissue. Intriguingly, we discoveredstatistically signiWcant and divergent levels of gene expression between the two isolates proWled for 64 genes. The results suggest thatincorporating more than one isolate in the experimental design oVers a means of categorizing the large collection of candidate genes thattranscriptional proWling typically identiWes into those that are strain-speciWc and those that characterize the entire species.
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| 6. |
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| 7. |
- Zhao, Ming, et al.
(författare)
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Low-temperature molecular beam epitaxy growth of Si/SiGe THz quantum cascade structures on virtual substrates
- 2006
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090. ; 508:1-2, s. 24-28
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Tidskriftsartikel (refereegranskat)abstract
- Si/SiGe quantum cascade structures containing superlattice up to 100 periods have been grown on SiGe virtual substrates by using solid-source molecular beam epitaxy at low temperature. The surface morphology and structural properties of the grown samples were characterized using various experimental techniques. It has been concluded that the structures were completely symmetrically strained with high crystalline quality, precise layer parameters, and excellent reproducibility. Electroluminescence was observed with peaked intensity at 3 THz at both 4 and 40 K, which agrees very well with expected interwell intersubband transition according to the design.
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| 8. |
- Zhao, Ming, et al.
(författare)
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Molecular beam epitaxy growth of Si/SiGe bound-to-continuum quantum cascade structures for THz emission
- 2008
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 517:1, s. 34-37
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Tidskriftsartikel (refereegranskat)abstract
- A Si/SiGe bound-to-continuum quantum cascade design for THz emission was grown using solid-source molecular beam epitaxy on Si0.8Ge0.2 virtual substrates. The growth parameters were carefully studied and several samples with different boron doping concentrations were grown at optimized conditions. Extensive material characterizations revealed a high crystalline quality of the grown structures with an excellent growth control. Layer undulations resulting from a nonuniform strain field, introduced by high doping concentration, were observed. The device characterizations suggested that a modification on the design was needed in order to enhance the THz emission.
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