| 1. |
- Algesten, Grete, et al.
(författare)
-
Organic carbon budget for the Gulf of Bothnia
- 2006
-
Ingår i: Journal of Marine Systems. - : Elsevier BV. - 0924-7963 .- 1879-1573. ; 63:3-4, s. 155-161
-
Tidskriftsartikel (refereegranskat)abstract
- We calculated input of organic carbon to the unproductive, brackish water basin of the Gulf of Bothnia from rivers, point sources and the atmosphere. We also calculated the net exchange of organic carbon between the Gulf of Bothnia and the adjacent marine system, the Baltic Proper. We compared the input with sinks for organic carbon; permanent incorporation in sediments and mineralization and subsequent evasion of CO2 to the atmosphere. The major fluxes were riverine input (1500 Gg C year(-1)), exchange with the Baltic Proper (depending on which of several possible DOC concentration differences between the basins that was used in the calculation, the flux varied between an outflow of 466 and an input of 950 Gg C year(-1)), sediment burial (1100 Gg C year) and evasion to the atmosphere (3610 Gg C year(-1)). The largest single net flux was the emission of CO2 to the atmosphere, mainly caused by bacterial mineralization of organic carbon. Input and output did not match in our budget which we ascribe uncertainties in the calculation of the exchange of organic carbon between the Gulf of Bothnia and the Baltic Proper, and the fact that CO2 emission, which in our calculation represented 1 year (2002) may have been overestimated in comparison with long-term means. We conclude that net heterotrophy of the Gulf of Bothnia was due to input of organic carbon from both the catchment and from the Baltic Proper and that the future degree of net heterotrophy will be sensible to both catchment export of organic carbon and to the ongoing eutrophication of the Baltic Proper.
|
|
| 2. |
- Dicksved, Johan, et al.
(författare)
-
Molecular analysis of the gut microbiota of identical twins with Crohn's disease
- 2008
-
Ingår i: The ISME Journal. - : Nature Publishing Group. - 1751-7362 .- 1751-7370. ; 2:7, s. 716-727
-
Tidskriftsartikel (refereegranskat)abstract
- Increasing evidence suggests that a combination of host genetics and the composition of the gut microbiota are important for development of Crohn's disease (CD). Our aim was to study identical twins with CD to determine microbial factors independent of host genetics. Fecal samples were studied from 10 monozygotic twin pairs with CD (discordant n=6 and concordant n=4) and 8 healthy twin pairs. DNA was extracted, 16S rRNA genes were PCR amplified and T-RFLP fingerprints generated using general bacterial and Bacteroides group-specific primers. The microbial communities were also profiled based on their percentage G+C contents. Bacteroides 16S rRNA genes were cloned and sequenced from a subset of the samples. The bacterial diversity in each sample and similarity indices between samples were estimated based on the T-RFLP data using a combination of statistical approaches. Healthy individuals had a significantly higher bacterial diversity compared to individuals with CD. The fecal microbial communities were more similar between healthy twins than between twins with CD, especially when these were discordant for the disease. The microbial community profiles of individuals with ileal CD were significantly different from healthy individuals and those with colonic CD. Also, CD individuals had a lower relative abundance of B. uniformis and higher relative abundances of B. ovatus and B. vulgatus. Our results suggest that genetics and/or environmental exposure during childhood, in part, determine the gut microbial composition. However, CD is associated with dramatic changes in the gut microbiota and this was particularly evident for individuals with ileal CD.
|
|
| 3. |
- Dicksved, Johan, et al.
(författare)
-
Molecular characterization of the stomach microbiota in patients with gastric cancer and in controls
- 2009
-
Ingår i: Journal of Medical Microbiology. - : Microbiology Society. - 0022-2615 .- 1473-5644. ; 58:4, s. 509-516
-
Tidskriftsartikel (refereegranskat)abstract
- Persistent infection of the gastric mucosa by Helicobacter pylori can initiate an inflammatory cascade that progresses into atrophic gastritis, a condition associated with reduced capacity for secretion of gastric acid and an increased risk of developing gastric cancer. The role of H. pylori as an initiator of inflammation is evident but the mechanism for development into gastric cancer has not yet been proven. A reduced capacity for gastric acid secretion allows survival and proliferation of other microbes that normally are killed by the acidic environment. It has been postulated that some of these species may be involved in the development of gastric cancer; however, their identities are poorly defined. In this study, the gastric microbiota from ten patients with gastric cancer was characterized and compared with that from five dyspeptic controls using the molecular profiling approach terminal restriction fragment length polymorphism (T-RFLP), in combination with 16S rRNA gene cloning and sequencing. T-RFLP analysis revealed a complex bacterial community in the cancer patients that was not significantly different from that in the controls. Sequencing of 140 clones revealed 102 phylotypes, with representatives from five bacterial phyla (Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria and Fusobacteria). The data revealed a relatively low abundance of H. pylori and showed that the gastric cancer microbiota was instead dominated by different species of the genera Streptococcus, Lactobacillus, Veillonella and Prevotella. The respective role of these species in development of gastric cancer remains to be determined.
|
|
| 4. |
- Gunnarsson, Rebeqa, et al.
(författare)
-
Screening for copy-number alterations and loss of heterozygosity in chronic lymphocytic leukemia-A comparative study of four differently designed, high resolution microarray platforms
- 2008
-
Ingår i: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257 .- 1098-2264. ; 93, s. 0536-0536
-
Tidskriftsartikel (refereegranskat)abstract
- Screening for gene copy-number alterations (CNAs) has improved by applying genome-wide microarrays, where SNP arrays also allow analysis of loss of heterozygozity (LOH). We here analyzed 10 chronic lymphocytic leukemia (CLL) samples using four different high-resolution platforms: BAC arrays (32K), oligonucleotide arrays (185K, Agilent), and two SNP arrays (250K, Affymetrix and 317K, Illumina). Cross-platform comparison revealed 29 concordantly detected CNAs, including known recurrent alterations, which confirmed that all platforms are powerful tools when screening for large aberrations. However, detection of 32 additional regions present in 2-3 platforms illustrated a discrepancy in detection of small CNAs, which often involved reported copy-number variations. LOH analysis using dChip revealed concordance of mainly large regions, but showed numerous, small nonoverlapping regions and LOH escaping detection. Evaluation of baseline variation and copy-number ratio response showed the best performance for the Agilent platform and confirmed the robustness of BAC arrays. Accordingly, these platforms demonstrated a higher degree of platform-specific CNAs. The SNP arrays displayed higher technical variation, although this was compensated by high density of elements. Affymetrix detected a higher degree of CNAs compared to Illumina, while the latter showed a lower noise level and higher detection rate in the LOH analysis. Large-scale studies of genomic aberrations are now feasible, but new tools for LOH analysis are requested.
|
|
| 5. |
|
|
| 6. |
- Jansson, Johan, 1974-, et al.
(författare)
-
Constructing Scandinavian design : Cyclical clusters in global circuits
- 2009
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper explores the notion that the ‘origins’ of cultural products are built up in a dialectical relationship between the products of a cultural cluster and its place. Traditionally, research on cultural agglomerations has posited direct links between products and place: Hollywood films, Paris fashion, Italian design. It has been thought that regional and industrial success can be at least partly explained by mutual reinforcing effects: the industry adds to the local/regional brand and vice versa. This view, we suggest, is too one dimensional to explain the ‘origins’ of cultural products or to explain how origins embed a place. In particular, we suggest that understandings of connections between cultural products and place must be put in the context of the role ‘cyclical clusters’ in global circuits have in the ongoing constitution and reconstitution of spatial identifiers and brands. The paper uses the example of ‘Scandinavian Design’ which in its 50 year history has become an important identifier and brand used by design, architecture and fashion consumers and industries around the world to imbue cultural products and firms with various intangible values. The paper uses the example to show that: (i) industrial narratives can be crucial to producing imagined geographies of cultural production; and (ii) that such narratives of place have complex geographies that should be understood less in terms of their roots in that place than in terms of their roots in discursive fields played out through cyclical clusters in global circuits. The paper concludes by suggesting that we must go beyond thinking about cultural products ‘origins’ in terms of place-based constructs and instead think about how spatial narratives are constructed in global circuits of overlapping spaces that are timed and arranged in such a way that spaces can be reproduced, reenacted and renewed over time.
|
|
| 7. |
- Jansson, Johan
(författare)
-
Inside the internet industry : The importance of proximity in accessing knowledge in the agglomeration of internet firms in Stockholm
- 2008
-
Ingår i: European Planning Studies. - : Informa UK Limited. - 0965-4313 .- 1469-5944. ; 16:2, s. 211-228
-
Tidskriftsartikel (refereegranskat)abstract
- This paper deals with the question of agglomeration of economic of activities and the internet industry in Stockholm, Sweden. The paper discusses the importance of proximity, especially in the knowledge transmission, and uses a theoretical framework of localized and tacit knowledge. The empirical findings suggests that firms within the internet industry are located in close proximity to each other because of the importance of dense informal interpersonal networks, that facilitate the search for new customers and collaborators. The findings also stress the importance of proximity in creating these dense networks and being in the right place at the right time.
|
|
| 8. |
- Jansson, Johan, 1974-
(författare)
-
Internetbranschen i Stockholms innerstad : En studie av agglomerationsfördelar, sociala nätverksrelationer och informationsflöden
- 2005
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with questions concerning spatial agglomeration of economic activities. The object of study is the Internet industry in central Stockholm. Through the use of statistical data and an interview study the Internet industry is described, measured, and analyzed through theories concerning agglomerations, social network relations, and knowledge and information flows. These theories are interpreted through five agglomeration themes related to the role of customers, subcontractors and partners, competitors, financing, and labour market, respec-tively.The research has recognized the importance of proximity to create and maintain social networks, and to spread information and knowledge, especially tacit knowledge. The thesis also shows how social networks, and information and knowledge flows have an essential role in all the five agglomeration themes that are analyzed. The results of this analysis show that the proximity to customers is the most important factor for the location of the Internet indus-try. Also, the local labour market and access to suppliers and partners are important factors. Competitors and rivals have a role to play when it comes to the diffusion of knowledge and information, although its importance as a location factor is hard to estimate. The analysis of the firms’ financing demonstrate that this factor hardly has been of crucial importance for the location of the Internet industry, but access to (venture) capital might have been of indirect importance for the location and the pace of the development of the Internet industry.
|
|
| 9. |
|
|
| 10. |
- Johansson, Magnus, 1976-, et al.
(författare)
-
Prolactin treatment improves engraftment and function of transplanted pancreatic islets
- 2009
-
Ingår i: Endocrinology. - : The Endocrine Society. - 0013-7227 .- 1945-7170. ; 150:4, s. 1646-1653
-
Tidskriftsartikel (refereegranskat)abstract
- Transplantation of pancreatic islets is clinically used to treat type 1 diabetes, but requires multiple donors. Previous experimental studies have demonstrated that transplanted islets have a low blood vessel density, which leads to a hypoxic microenvironment. The present study tested the hypothesis that experimental prolactin pretreatment, a substance which seems to stimulate angiogenesis in endogenous islets, would increase graft blood vessel density, thereby improving transplantation outcome. Pancreatic islets from C57BL/6 mice were incubated with prolactin (500 ng/ml) or vehicle during the last 24 h of culture before syngeneic transplantation beneath the renal capsule, or recipients were injected with prolactin or vehicle for the first 7 days after transplantation. One month post-transplantation, graft vascular density, blood flow, oxygen tension, endocrine volume and function was evaluated. Also human islets were incubated with prolactin or vehicle before experimental transplantation and investigated for vascular engraftment. Vascular engraftment of syngeneically transplanted mouse islets was improved by both in vivo and in vitro prolactin pretreatment. Moreover, prolactin pretreatment in vitro of islets used for transplantation improved recovery from diabetes in a minimal islet mass model. Interestingly, also human islets subjected to prolactin treatment before experimental transplantation demonstrated improved revascularization, blood perfusion and oxygen tension when evaluated one month post-transplantation. We conclude that prolactin may improve engraftment of transplanted pancreatic islets. The protocol with pretreatment of islets ex vivo could minimize the risk of side effects when used in the clinical setting.
|
|
