| 1. |
- Larsson, AL, et al.
(författare)
-
Optical absorption of Li-intercalated polycrystalline tungsten oxide films : comparison to large polaron theory
- 2003
-
Ingår i: Solid State Ionics. - : Elsevier. - 0167-2738 .- 1872-7689. ; 165:1-4, s. 35-41
-
Tidskriftsartikel (refereegranskat)abstract
- Thin films of polycrystalline tungsten trioxide were manufactured using DC magnetron sputtering. Films of different thickness were deposited onto glass substrates coated with indium tin oxide (ITO). The crystallinity was confirmed by X-ray diffraction, and the grain size was found to be 30 nm. Li ions and electrons were intercalated into the sample using a three-electrode setup. The samples were submitted to optical characterization by spectrophotometry, in the visible and infrared ranges. The optical spectra were recorded at different intercalation states, and the absorption of the films was obtained. At low intercalation levels, a pronounced absorption peak was observed to be centered at a wavelength of 1.8 mum. Upon intercalation, the inserted electrons enter the conduction band, but due to a strong electron-phonon interaction, they are believed to form localized polarons. Calculations of optical absorption by large polaron theory were carried out and the position of the observed peak was in good agreement with the theory. A crossover from dielectric (low reflectance and clear phonon absorption bands) to metallic (high infrared reflectance) occurred at a Li intercalation level of around 0.05-0.15 Li/W. This may be due to overlap of the polaron states. (C) 2003 Elsevier B.V All rights reserved.
|
|
| 2. |
- Magnusson, Magnus, et al.
(författare)
-
Spatial and temporal variation of hantavirus bank vole infection in managed forest landscapes
- 2015
-
Ingår i: Ecosphere. - 2150-8925 .- 2150-8925. ; 6:9
-
Tidskriftsartikel (refereegranskat)abstract
- Zoonoses are major contributors to emerging infectious diseases globally. Hemorrhagic fever with renal syndrome (HFRS) is a zoonosis caused by rodent-borne hantaviruses. In Europe, Puumala hantavirus (PUUV) carried and shed by the bank vole (Myodes glareolus), is the most common cause of HFRS. We explore the relationship of PUUV infection in bank voles, as measured by PUUV antibody detection, with habitat and landscape scale properties during two successive vole cycles in boreal Sweden. Our analysis revealed that PUUV infection in the population was not uniform between cycles and across different landscapes. The mean density index of PUUV antibody positive and negative bank voles were highest in old forest, second highest in cut-over forest (approx. 0-30 years old) and lowest on mires. Most importantly, old forest was the core habitat, where PUUV antibody positive bank voles were found through the low density phase and the transition between successive vole cycles. In spring, occurrence of antibody positive voles was negatively related to the proportion of cut-over forest in the surrounding landscape, suggesting that large scale human induced land-use change altered the occurrence of PUUV infection in voles which has not been shown before. Dependence of PUUV infection on habitat and landscape structure, and the variation in infection load within and between cycles are of importance for human risk assessment.
|
|
| 3. |
- Niklasson, Bo, et al.
(författare)
-
Association of zoonotic Ljungan virus with intrauterine fetal deaths
- 2007
-
Ingår i: Birth defects research. Clinical and molecular teratology. - : Wiley. - 1542-0752 .- 1542-0760. ; 79, s. 488-493
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: It has recently been shown that Ljungan virus (LV) is associated with disease in its wild rodent reservoir. In addition, it has been demonstrated that LV causes malformations and perinatal death in a mouse model. The question was therefore raised whether LV is a zoonotic agent in humans. METHODS: Population fluctuations of native rodents in Sweden were compared to the incidence of intrauterine fetal deaths (IUFDs) using the Swedish national hospitalization database. Formalin-fixed tissues from cases of IUFD were investigated using LV-specific immunohistochemistry. RESULTS: Variation in the incidence of IU-FDs closely tracked the fluctuations in native rodent populations. LV was detected in the brain tissue in 4 of 10 cases of IUFDs investigated by immunochemistry. LV was also detected in the placenta in 5 of the 10 IUFD cases, but in none of 20 placentas from normal pregnancies. CONCLUSIONS: LV may play an important role in IUFDs.
|
|
| 4. |
- Niklasson, Bo, et al.
(författare)
-
Diabetes and myocarditis in voles and lemmings at cyclic peak densities--induced by Ljungan virus?
- 2006
-
Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 150:1, s. 1-7
-
Tidskriftsartikel (refereegranskat)abstract
- Although it is well-documented from theoretical studies that pathogens have the capacity to generate cycles, the occurrence and role of pathogens and disease have been poorly empirically studied in cyclic voles and lemmings. In screening for the occurrence of disease in cyclic vole and lemming populations, we found that a high proportion of live-trapped Clethrionomys glareolus, C. rufocanus, Microtus agrestis and Lemmus lemmus at high collective peak density, shortly before the decline, suffered from diabetes or myocarditis in northern Scandinavia. A high frequency of animals had abnormal blood glucose (BG) levels at the time of trapping (5-33%). In contrast, C. rufocanus individuals tested at a much lower overall density, and at an earlier stage relative to the decline in the following cycle, showed normal BG concentrations. However, a high proportion (43%) of a sample of these individuals kept in captivity developed clinical diabetes within five weeks, as determined by BG levels and a glucose tolerance test performed at that later time. A new picornavirus isolated from the rodents, Ljungan virus (LV), was assumed to cause the diseases, as LV-induced diabetes and myocarditis, as well as encephalitis and fetal deaths, were observed in laboratory mice. We hypothesize that LV infection significantly affects morbidity and mortality rates in the wild, either directly or indirectly, by predisposing the rodents to predation, and is at least involved in causing the regular, rapid population declines of these cyclic voles and lemmings. Increased stress at peak densities is thought to be an important trigger for the development of disease, as the occurrence of disease in laboratory mice has been found to be triggered by introducing stress to LV-infected animals.
|
|
| 5. |
- Ekström, Jens-Ola, et al.
(författare)
-
Replication of Ljungan virus in cell culture : the genomic 5'-end, infectious cDNA clones and host cell response to viral infections
- 2007
-
Ingår i: Virus Research. - : Elsevier BV. - 0168-1702 .- 1872-7492. ; 130:1-2, s. 129-139
-
Tidskriftsartikel (refereegranskat)abstract
- Ljungan virus (LV) is a picornavirus recently isolated from bank voles (Clethrionomys glareolus). The previously uncharacterised 5'-end sequence of the LV genome was determined. Infectious cDNA clones were constructed of the wild type LV prototype strain 87-012 and of the cytolytically replicating cell culture adapted variant 87-012G. Virus generated from cDNA clones showed identical growth characteristics as uncloned virus stocks. Cell culture adapted LV, 87-012G, showed a clear cytopathic effect (CPE) at 3-4 days post-infection (p.i.). Virus titers, determined by plaque titration, increased however only within the first 18h p.i. Replication of LV (+) strand RNA was determined by real-time PCR and corresponded in time with increasing titers. In contrast, the amounts of the replication intermediate, the (-) strand, continued to increase until the cells showed CPE. This indicates separate controlling mechanisms for replication of LV (+) and (-) genome strands. Replication was also monitored by immunofluorescence (IF) staining. IF staining of both prototype 87-012 and the CPE causing 87-012G showed groups of 5-25 infected cells at 48h p.i., suggesting a, for picornaviruses, not previously described direct cell-to-cell transmission.
|
|
| 6. |
- Gräns, Albin, 1979, et al.
(författare)
-
Stunning fish with CO2 or electricity: contradictory results on behavioural and physiological stress responses
- 2016
-
Ingår i: Animal. - 1751-7311 .- 1751-732X. ; 10:2, s. 294-301
-
Tidskriftsartikel (refereegranskat)abstract
- Studies that address fi sh welfare before slaughter have concluded that many of the traditional systems used to stun fi sh including CO 2 narcosis are unacceptable as they cause avoidable stress before death. One system recommended as a better alternative is electrical stunning, however, the welfare aspects of this method are not yet fully understood. To assess welfare in aquaculture both behavioural and physiological measurements have been used, but few studies have examined the relationship between these variables. In an on-site study aversive behaviours and several physiological stress indicators, including plasma levels of cortisol and ions as well as blood physiological variables, were compared in Arctic char ( Salvelinus alpinus ) stunned with CO 2 or electricity. Exposure to water saturated with CO 2 triggered aversive struggling and escape responses for several minutes before immobilization, whereas in fi sh exposed to an electric current immobilization was close to instant. On average, it took 5 min for the fi sh to recover from electrical stunning, whereas fi sh stunned with CO 2 did not recover. Despite this, the electrically stunned fi sh had more than double the plasma levels of cortisol compared with fi sh stunned with CO 2 . This result is surprising considering that the behavioural reactions were much more pronounced following CO 2 exposure. These contradictory results are discussed with regard to animal welfare and stress physiological responses. The present results emphasise the importance of using an integrative and interdisciplinary approach and to include both behavioural and physiological stress indicators in order to make accurate welfare assessments of fish in aquaculture.
|
|
| 7. |
|
|
| 8. |
- Niklasson, Mia, et al.
(författare)
-
Mesenchymal transition and increased therapy resistance of glioblastoma cells is related to astrocyte reactivity
- 2019
-
Ingår i: Journal of Pathology. - : WILEY. - 0022-3417 .- 1096-9896. ; 249:3, s. 295-307
-
Tidskriftsartikel (refereegranskat)abstract
- Grade IV astrocytoma/glioblastoma multiforme (GBM) is essentially incurable, partly due to its heterogenous nature, demonstrated even within the glioma-initiating cell (GIC) population. Increased therapy resistance of GICs is coupled to transition into a mesenchymal (MES) cell state. The GBM MES molecular signature displays a pronounced inflammatory character and its expression vary within and between tumors. Herein, we investigate how MES transition of GBM cells relates to inflammatory responses of normal astroglia. In response to CNS insults astrocytes enter a reactive cell state and participate in directing neuroinflammation and subsequent healing processes. We found that the MES signature show strong resemblance to gene programs induced in reactive astrocytes. Likewise, astrocyte reactivity gene signatures were enriched in therapy-resistant MES-like GIC clones. Variable expression of astrocyte reactivity related genes also largely defined intratumoral GBM cell heterogeneity at the single-cell level and strongly correlated with our previously defined therapy-resistance signature (based on linked molecular and functional characterization of GIC clones). In line with this, therapy-resistant MES-like GIC secreted immunoregulatory and tissue repair related proteins characteristic of astrocyte reactivity. Moreover, sensitive GIC clones could be made reactive through long-term exposure to the proinflammatory cytokine interleukin 1 beta (IL1 beta). IL1 beta induced a slow MES transition, increased therapy resistance, and a shift in DNA methylation profile towards that of resistant clones, which confirmed a slow reprogramming process. In summary, GICs enter through MES transition a reactive-astrocyte-like cell state, connected to therapy resistance. Thus, from a biological point of view, MES GICs would preferably be called 'reactive GICs'. The ability of GBM cells to mimic astroglial reactivity contextualizes the immunomodulatory and microenvironment reshaping abilities of GBM cells that generate a tumor-promoting milieu. This insight will be important to guide the development of future sensitizing therapies targeting treatment-resistant relapse-driving cell populations as well as enhancing the efficiency of immunotherapies in GBM. (c) 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
|
|
| 9. |
- Nix, W Allan, et al.
(författare)
-
Detection of all known parechoviruses by real-time PCR.
- 2008
-
Ingår i: Journal of clinical microbiology. - 1098-660X. ; 46:8, s. 2519-24
-
Tidskriftsartikel (refereegranskat)abstract
- The Parechovirus genus of the Picornaviridae family contains two species, Human parechovirus (HPeV) and Ljungan virus (LV). The HPeVs (including the former echoviruses 22 and 23, now HPeV type 1 (HPeV1) and HPeV2, respectively) cause a wide spectrum of disease, including aseptic meningitis, gastroenteritis, encephalitis, acute respiratory illness, and neonatal sepsis-like disease. The LVs were isolated from bank voles in Sweden during a search for an infectious agent linked to fatal myocarditis cases in humans. Because of the decline in use of cell culture and neutralization to investigate enterovirus-like disease, very few laboratories currently have the capability to test for parechoviruses. We have developed a real-time reverse transcription-PCR (RT-PCR) assay for detection of all known members of the genus Parechovirus. The assay targets the conserved regions in the 5' nontranslated region (5'NTR) of the parechovirus genome and can detect both HPeVs and LVs, unlike other published parechovirus 5' NTR assays, which only detect known HPeVs or only LVs. HPeV and LV can be differentiated by sequencing the 5'NTR real-time RT-PCR amplicon, when needed. The assay is approximately 100 times more sensitive than cell culture and may be used to test original clinical specimens. The availability of a broad-specificity PCR method should facilitate the detection of new human parechoviruses, as well as new parechoviruses in other mammalian species, and provide an opportunity to investigate the role of these viruses in human and animal disease.
|
|
| 10. |
- Samsioe, Annika, et al.
(författare)
-
Intrauterine death, fetal malformation, and delayed pregnancy in Ljungan virus-infected mice
- 2006
-
Ingår i: Birth defects research. Part B. Developmental and reproductice toxicology. - : Wiley. - 1542-9733 .- 1542-9741. ; 77:4, s. 251-256
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: A picornavirus (Ljunganvirus [LV]) has recently been associated with disease during pregnancy in its natural rodent reservoir and in humans. A study of laboratory mice infected under controlled conditions was therefore undertaken. METHODS: CD-1 female mice were infected gestational day two and subjected to varying regimes of stress. RESULTS: LV infection in combination with stress resulted in uterine resorptions, malformations, and neonatal death. A short delay in time to first pregnancy and births was observed in pairs infected in utero. CONCLUSIONS: LV is found in different species of native animals in both Europe and the United States and human epidemiological evidence connects LV and human reproduction, while the observations here indicate that LV is responsible for reproductive problems in a laboratory mouse model. The current findings suggest that the hypothesis that LV also causes disease in pregnant women and their offspring deserves further study.
|
|
